Team 19 Final Report

THE FLORIDA A&M UNIVERSITY - FLORIDA STATE UNIVERSITY

COLLEGE OF ENGINEERING

FALL DESIGN PACKAGE

ME Team #19 / EE Team #10:The HEXCAVATOR Project

By

ALEKS FEDORIWDUNCAN HALDANE

ARTHUR PACKMICHAEL PEARSE

CARLOS RUIZ

A Senior Design Project submitted to theDepartment of Mechanical Engineering &

Department of Electrical & Computer Engineering

Submitted:December 7, 2010

Degree Awarded:Spring Semester, 2011

TABLE OF CONTENTS

List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

1 Introduction 11.1 Systems Engineering Approach . . . . . . . . . . . . . . . . . . . . . . . . . 1

2 Design Concepts 32.1 Locomotion Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.1.2 Tracked Locomotion . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.1.3 Wheeled Locomotion . . . . . . . . . . . . . . . . . . . . . . . . . . . 52.1.4 Legged Locomotion . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.2 Chassis and Integration Concepts . . . . . . . . . . . . . . . . . . . . . . . . 62.2.1 ABS Chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.2.2 Steel Tubing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.2.3 Aluminum Tubing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.2.4 Titanium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.3 Excavation Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.3.2 Bucket Chain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.3.3 Bucket Wheel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.4 Offloading Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.4.2 Power Screw System . . . . . . . . . . . . . . . . . . . . . . . . . . . 102.4.3 Pulley System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102.4.4 Linear Actuator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.5 Controller Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132.6 Telerobotic Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132.7 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152.8 Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3 Final Design 173.1 Locomotion Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183.2 Chassis Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213.3 Excavation and Offloading Design . . . . . . . . . . . . . . . . . . . . . . . 213.4 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

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4 Acknowledgments 24

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

A Appendix 26A.1 Part Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26A.2 Data Sheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38A.3 Competition Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

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LIST OF FIGURES

1.1 : A team from the 2010 Lunabotics competition tuning up their robot beforecompetition [1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 : Needs Analysis Flow Diagram for the HEXCAVATOR Project . . . . . . . 2

2.1 The LT2 Treaded Robot [2] . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2.2 The RHex Robot [3] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.3 The first version of the Edubot robot implemented an ABS chassis [4] . . . . 7

2.4 Prototype This’ All-terrain vehicle struggling to lift its heavy chassis. [5] . . 7

2.5 : The Lockheed SR-71A Blackbird is composed of 93% titanium alloy. [6] . . 8

2.6 : Bucket Chain Excavator [7] . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.7 : Bucket wheel Excavator [8] . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.8 : Power Screw System [9] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.9 : Pulley System [10] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.10 : Linear Actuator [11] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.11 : LM3S9B96 Development Kit [12] . . . . . . . . . . . . . . . . . . . . . . . 14

2.12 : WiFly Serial Communication Module [13] . . . . . . . . . . . . . . . . . . . 15

3.1 : Final Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.2 : The SLIP Model of the RHex [14] . . . . . . . . . . . . . . . . . . . . . . . 18

3.3 : The Buehler Clock [14] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

3.4 : The Pseudo-Rigid Body Model [15] . . . . . . . . . . . . . . . . . . . . . . 20

3.5 : FEM Analysis of the RHex leg . . . . . . . . . . . . . . . . . . . . . . . . . 20

3.6 : FEA Simulation of the chassis undergoing vertical side loading . . . . . . . 21

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3.7 : Main Power Supply Circuit Diagram . . . . . . . . . . . . . . . . . . . . . 22

3.8 : MCU Circuit Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

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ABSTRACT

In May 2011, the National Aeronautics and Space Administration (NASA) will be hosting itssecond annual Lunabotics Mining Competition. The goal of an entry into the competitionis to design a robot that will result in innovative ideas and solutions that could shapethe future of lunar and extra-planetary missions performed by NASA. The project teamconsists of undergraduate and graduate students from Florida A & M University and FloridaState University majoring in Electrical, Computer and Mechanical Engineering. The team’smission is to design and build a robot that can excavate at least 10 kilograms (kg) of regolith(lunar soil) and transfer it to a container within 15 minutes. The robot will be competingin a box containing eight tons of simulated regolith. The innovative design of our lunarexcavator will be based on a hexapedal walking platform. The design also incorporates abucket-chain excavator, a bucket operated via pulley system for storage and unloading ofregolith, and various components for control. Along with the fabrication of a lunar miningrobot, the team will perform community outreach for K-12 grade students in the areasof Science, Technology, Engineering, and Math (STEM) at both schools and communityevents. The total amount of funds raised to date is $14,280. The current projected budget is$21.255. Any denomination or material(s) donated will go directly towards the constructionof the robot and community outreach.

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CHAPTER 1

INTRODUCTION

This year, the Florida A M University-Florida State University College of Engineering iscontinuing its interdisciplinary collaboration between the Electrical/Computer Engineeringand the Mechanical Engineering Departments for their Senior Design Projects. The goalof the project is to expose senior students to the concepts of design, project management,engineering team organization, and professionalism. Five undergraduate students from bothuniversities have been selected to participate in this project, as well as five graduate studentsfor advising and construction assistance. The requirements of the Lunar Regolith ExcavatorStudent Competition are as follows: design a robot capable of excavating 10 kg of regolithin 15 minutes while weighing less than 80 kg. This robot must be able to fit in a box thatis 1.5 meters long, 0.75 meters wide, and 2 meters high.

Figure 1.1: : A team from the 2010 Lunabotics competition tuning up their robotbefore competition [1]

The team is tasked with creating a robot capable of meeting and exceeding all require-ments set forth by NASA for the competition. As the students are designing, constructing,synthesizing and analyzing their robot, they will perform community outreach for K-12grade students in the areas of Science, Technology, Engineering, and Math (STEM). Mostrecently, the team has assisted in coaching and teaching the students of Maclay School’sLego Robotics Club as they prepare for their own competitions.

1.1 Systems Engineering Approach

The design team will be applying the systems engineering approach to the developmentof the robotic platform. The approach of incorporating a multidisciplinary engineering teamis the first step toward successful systems engineering. Subsystems of the project have been

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identified as Excavation Unloading Subsystems, Locomotion Subsystems, Chassis Integra-tion Subsystems, Power Subsystems, Micro-Controller Communications Subsystems, andControl Subsystems. These subsystems cover the required functions of the platform and allsolutions will be integrated into a single functional body.

The needs analysis flow diagram represents the needs of the customer, the project, andidentifies specific elements and interfaces to address the needs. Figure 1.2 outlines theneeds analysis for the HEXCAVATOR Project including a basis for the individual systems,interfaces within the systems, and the overall goals of the project (requirements).

The system requirements were identified by the customer, in this case they representthe rules outlined by NASA for the competition. The requirements were broken downinto specific goals that the robot needed to accomplish. These goals included traversinga large area, excavation of regolith, regolith transport, obstable avoidance, power storageand regulation, information relay, signal processing, and many more. Once the goals wereidentified, they were grouped based on similarity and purpose. These groups were thenidentified as the specific subsystems of the HEXCAVATOR Project Robot and representthe categories necessary to fulfill all customer requirements.

Figure 1.2: : Needs Analysis Flow Diagram for the HEXCAVATOR Project

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CHAPTER 2

DESIGN CONCEPTS

2.1 Locomotion Concepts

2.1.1 Introduction

The lunar surface significantly increases the difficulty of locomotion experienced byvehicles traversing it. The NASA Lunar Regolith Competition has created the ’Lunarena’for the lunar excavators to compete in. The Lunarena is a 3.88m x 7.38 m box filled witha lunar regolith simulant called Black Point-1 (BP-1). BP-1 consists of ground volcanicash and soil and this material presented the biggest problem for last year’s competitors.Sand was a common practice substrate for teams competing in last year’s competition.The tracked locomotion subsystem developed by last year’s team, The ARTEMIS Project,performed admirably in sand, which was their testing substrate. However, when theyoperated their robot in the lunar regolith simulant, they experienced immediate difficultieswith locomotion. These difficulties were so advanced that the robot lost functionality beforeit traversed more than a meter. Robots also have to traverse around or over rocks 30 cmin diameter and craters of a similar size. One of our first activities as a group was to watchas many videos of the last year’s competition robots as we could find. We saw that thelocomotion difficulties experienced by last year’s team were not unique to their robot. Fromwatching these videos, we developed and evaluated several locomotion concepts.

2.1.2 Tracked Locomotion

In theory tracked systems offer the highest traction and maneuverability. The flatsurface of the tread creates a very high power to surface contact ratio. The tracked systemsimplemented in last year used a differential drive steering system that allowed for simplecontrol scheme of the robot while allowing for very high maneuverability. These reasonsmake tracked locomotion a very attractive option for all walks of off-road vehicles. Thischoice of locomotion was entirely justified for last year’s team because of the demonstratedpracticality of treaded locomotion as shown by robots similar to Figure ??. They used validdecision making criteria to select this method of locomotion, but the competition presentedunforeseen difficulties. The very fine texture of the regolith clogged the drive sprockets andimmobilized the tracks in a short period of time. Other treaded entries at the competitionexperienced similar difficulties.

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Figure 2.1: The LT2 Treaded Robot [2]

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2.1.3 Wheeled Locomotion

The other main method used at last year’s competition was wheeled locomotion. Therules stipulate that all main systems must be able to be used in a lunar environment. Thismeans that any part of the robot, such as a wheel, must be able to be used in a vacuum.Therefore any sort of inflatable or foam filled wheel is not allowed by the competition rules.The main difficulty that wheeled robots had in last year’s competition was traversing theobstacles placed by the NASA officials. For traversing obstacles, it is desirable to havelarge wheels. Because these wheels cannot be inflatable, large wheels would be unreason-ably heavy. This is why most of the teams at last year’s competition chose small wheels.The main drawbacks of wheeled locomotion are reduced maneuverability as compared totracked locomotion and reduced capability for traversing obstacles. One notable exampleof the drawbacks of wheeled locomotion from last year was Carnegie Mellon’s entry to thecompetition. They were the favorite to win the competition last year with a budget ofover $60,000. However, the judges placed the obstacles just right so that their wheeledrobot could not clear them. Almost all of the wheeled robots at last year’s competitionexperienced issues with low ground clearance.

2.1.4 Legged Locomotion

After discussing the results of last year’s competition with the members of the ARTEMISProject and examining the successes and failures of last year’s teams, we examined a newmethod of locomotion. Legged robotic locomotion offers distinct advantages over othermethods when a robot is operating in rough unknown terrain. The RHex, shown in Fig-ure ?? is a hexapedal running and walking robotic platform. It is the fastest running robotin rough terrain and a very large base of knowledge already exists for robust walking gaitsdesigned for stability in rough terrain. The ’C’ shaped legs of the RHex robot offer discretepoint of contact which allows for traversal of obstacles which are taller than the robot it-self. The legged mode of locomotion is also impervious to the dust related complicationsthat sabotaged the robots in last year’s competition. The ’C’ leg is not affected by dustclogging, and these legs give the robot a high ground clearance while keeping the weightof the locomotion appendage low. There are also several drawbacks of legged locomotion.The complexity of the control scheme is greatly increased and like wheeled locomotion, itis not as maneuverable as differentially steered tracked locomotion.

Legged locomotion was selected as the motion strategy for this robot. This system willbe the most complex at the competition and will involve the most testing to get working.However, by working out the complex issues associated with developing a robot capable oflegged locomotion, a robust system will be developed that should be a competitive entryat this competition. By facilitating the ease of locomotion, strategies can be developedfor traversing the obstacle field multiple times, a capability that was lacking in last year’sentries. Also, the legged nature of the platform allows for unique mobility by manipulatingthe legs in any number of different modes.

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Figure 2.2: The RHex Robot [3]

2.2 Chassis and Integration Concepts

2.2.1 ABS Chassis

ABS plastic is extremely lightweight compared to any metal, easy machinable, easy toobtain, and very affordable. It is these qualities that made ABS an initially attractiveoption, especially with weight being a major factor within the competition. A chassis madeout of ABS was used on an educational version of RHex known as Edubot and can be seenin Figure 2.3. This chassis could be made rather quickly at a low cost, but unfortunatelyABS is not only a lightweight but also a low strength material and could prove to be a riskif the robot were to fall or hit an obstacle.

2.2.2 Steel Tubing

Steel is a proven high strength material that would be able to handle the forces andstresses applied on the robot if it were to misstep or run into an obstacle. Steel has beenused before for a similar application because of its high strength. The application whichis being referred to is a Discovery television program known as Prototype This!. On oneepisode they were given the task to build a larger version of RHex which a person would beable to ride in. The material chosen for their chassis was steel tubing, unfortunately theyran into problems later on with the chassis be too heavy. With the heavier than expectedchassis, the motors were not able to supply enough power to lift the overweight robot seenin Figure 2.4.

2.2.3 Aluminum Tubing

Aluminum is widely used for many different applications due to its high strength-to-weight ratio, machinability, low cost, and availability in numerous shapes, sizes and tempers.

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Figure 2.3: The first version of the Edubot robot implemented an ABS chassis [4]

Figure 2.4: Prototype This’ All-terrain vehicle struggling to lift its heavy chassis. [5]

While not as strong as steel, its low density means that a chassis made out of aluminumwould be much lighter. Like the steel tubing, the aluminum would be used to create aframe in which the motors, gearboxes, electronics and batteries would be held securely. Abaseplate of aluminum would also be used in order to heat sink the batteries, electronics,and motors in order to avoid overheating any of the components.

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2.2.4 Titanium

Titanium was considered after the idea of using the material to build the chassis wasbrought to the team’s attention at the Mechanical Engineering Advisory Board (MEAC)Presentation. Titanium is another metal with an amazing strength-to-weight ratio, mostcommonly used on aircrafts, such as the SR-71A Blackbird Figure 2.5. After researchingwhat size and alloy of titanium tubing would be needed it was discovered that the overallweight of the chassis could be reduced though at a much greater financial cost compared tothe other concepts.

Figure 2.5: : The Lockheed SR-71A Blackbird is composed of 93% titanium alloy. [6]

2.3 Excavation Concepts

2.3.1 Introduction

As this project is the second attempt at the Lunabotics competition, the entries inthe previous competition were used as a reference when selecting efficient excavation de-signs. Initially all possible excavation designs were considered including: bucket chains,bulldozer, clamshell buckets, auger and bucket wheel. Through discussion with membersof the ARTEMIS design team who were present at the competition several of the designconcepts were immediately discarded due to impracticality and gross inefficiency. Afterdiscarding the unreasonable designs the bucket chain, and bucket wheel were the primarysystems being considered.

2.3.2 Bucket Chain

A bucket chain shown in Figure 2.6combines the excavation and transportation of thecollected material into one motion. A series of scoops are placed on a rotating chain system.As the system rotates the scoops collect material and transport it to a collection bin. Thisdirect transport of material reduces the amount wasted in transport over other systemssuch as a conveyor belt. Unfortunately, a larger amount of friction is encountered dueto the resistance of multiple buckets excavating and higher inertial values for the systemto begin rotating from a stopped position. This increase in force requires that the chainand supporting framework be stronger than a typical conveyor system, usually resulting inincreased weight.

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Figure 2.6: : Bucket Chain Excavator [7]

2.3.3 Bucket Wheel

A bucket wheel system, shown in Figure 2.7 is primarily used in very large scale mining.A large hollow wheel rotates with bucket attachments on the circumference. As the wheelrotates the buckets collect material and upon reaching the top of the wheel the materialis deposited onto a conveyor system which travels within the boom which supports androtates the wheel about the stationary track platform. Though a high rate of excavationcan be achieved with this system, it is difficult to time the excavation and conveyor systemsto minimize the amount of lost material while maintaining high energy efficiency.

Due to the nature of our locomotive platform, it is important to maintain balance withinthe system. A bucket wheel large enough to reach the surface of the regolith and excavatewithout compromising the strength of the frame would be prohibitively expensive and add aconsiderable amount of weight beyond the center of balance for the robot. Also, the natureof the supports for a bucket wheel system generally requires a system of counter weights toprevent tipping. Since weight is a dominating constraint for the robot’s design, this is nota viable option for excavation.

2.4 Offloading Concepts

2.4.1 Introduction

As with the excavation system, the designs for the offloading of regolith are primarilybased on the systems which were proven effective at the previous Lunabotics challenge.In order for a design to work on the walking platform it must have a minimal weightimpact and power consumption of its components while providing the required functionality

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Figure 2.7: : Bucket wheel Excavator [8]

and efficiency to operate successfully. The designs which were decided upon for furtherconsideration were the power screw, pulley and linear actuator.

2.4.2 Power Screw System

The power screw system, shown in Figure 2.8 consists of a threaded shaft upon whicha bearing block is fitted. As the shaft rotates the block is translated along the length ofthe shaft. This system is very light weight and requires very little torque from the motor tomove even while under load. This lift system is also able to move the collected regolith overthe lip of the collection bucket quite easily. However, due to the harmonic motion inducedby the robot as it travels across the course, it is possible that the screw and supporting rodscould be bent which would prevent the system from functioning properly. The screw itselfis made out of threaded steel which will add to the weight of the system.

2.4.3 Pulley System

The pulley system, shown in Figure 2.9 uses a supporting frame for the pulley tackleand simultaneously acts as a guide rail for the collection bucket. Though slightly tallerthan the power screw system the pulley requires that the bucket be directly beneath thepulley reel. To accomplish this, a cross beam is implemented which reduces the amountof sway in the support beams during locomotion. Using a tubular frame the weight canbe reduced while maintaining the structural stability of the system since the loading isprimarily compressive.

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Figure 2.8: : Power Screw System [9]

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Figure 2.9: : Pulley System [10]

2.4.4 Linear Actuator

Linear actuators, shown in Figure 2.10 are a simple design and would require little powerfrom the electrical system. They use several different methods from hydraulics, pneumaticsand screw systems to extend a piston to the desired position. Unfortunately they do nothave the range of motion required to reach the collection bin from the top of the robot.Also as this is a timed competition, the slow rate at which they are able to extend makesthem less suitable for this application.

Figure 2.10: : Linear Actuator [11]

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2.5 Controller Concepts

A robot is only as good as its controller. A controller is a device with micro-componentsused for various tasks and calculations. These tasks are used to read in data from sensorsand transmit certain information tell motors and relevant parts to operate as desired. Theresmany different options to chose from to perform the necessary operations. Firstly there areFPGAs. FPGA are not necessarily microcontroller but can perform the same functionsfor specified devices, such as cell phones or robots. The FPGA is purely hardware drivenincluding its language, VHDL. VHDL stands for VHSIC hardware description languagewhile VHISC stands for very high seed integrated circuits. Because theres no software theycan perform certain operations with incredible speed. The development FPGA boardstypically contain many I/O pins, and would be excellent at dealing with low-level systemsof the robot. The downside to such a device is the hardware language is far more difficult toprogram compared to a software language such as C++. Debugging can be quite difficultand many lines of code are implemented for relatively simple algorithms. The pins are notstandard I/O and the worst factor is the board must be reprogrammed whenever poweredoff. Next are microcontrollers. Microcontrollers are categorized by their bus size, suchas 8-bit, 16-bit, or 32-bit microcontrollers. 8-bit microcontrollers are typically used forrobot control in the industry. Their 8-bit format keeps them simple yet efficient in robotoperations. One option was the PIC processor. They are easy to initialize pins and set-up pin assignments, but are relatively slow. At about 16MHz its far from the fastestmicrocontroller. The 32 bit microcontrollers are far more complicated yet allow for muchmore options. 32-bit development kits are like small computers, in a sense. They have built-in LCD screens, USB ports, Ethernet ports, serial ports, and many GPIOs. This seems likea much better match for the desired robot. And the Ethernet port allows for easy accessfor wireless communication. The FPGA is ruled out immediately. It seems far too complexto implement an FPGA in such a complex robot. The programming and set-up would bepainstaking. The PIC processor is a fine microcontroller. Its very easy to initialize desiredpin functions and also has a huge community for support when assistance is needed. But itstoo slow compared to todays standards. A microcontroller with many PWMs is necessarydue to the hexapedal design. Six separate legs must be controlled independently along withmotors for excavation. The Texas Instruments LM3S9B96 Stellaris family development kit.It appears to be the best board for the job.

2.6 Telerobotic Interface

The robot needs to have a wireless control system. When deciding of the wirelesssystem, one must keep in mind of the 2s delay both ways on the line and the maximumbandwidth of 1Mb/s. This delay is provided by a computer provided at the contest whichruns an emulated wide area network. The robot then must have a way of connecting tothis network and somehow communicate with the operator on a computer on the other sideof the network. The chosen board contains a Ethernet port along with multiple GPIOsthat can serve as a serial communicator. This allows for multiple options. A serial-basedwireless device could be used to connect the MCU to NASAs wireless network. Anotheroption is simply hacking a router and connecting it to the Ethernet port of the MCU. The

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Figure 2.11: : LM3S9B96 Development Kit [12]

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problem with the router is its power consumption. The amount of power required to runthe router is monstrous compared to the serial-based wireless device. This provides thereasoning behind using the WiFly wireless serial interface device.

Figure 2.12: : WiFly Serial Communication Module [13]

Now to communicate with the wifly is another task that must be handled. Because thechosen wireless device is serial, our wireless output must be treated as a serial device. Toachieve this a laptop with the robots specific GUI will connect to NASAs wireless networkVIA router. A virtual-serial port must be created to simulate a direct serial connectionwith the WiFly. So the laptop connects to a router which then connects to NASAs wirelessnetwork, which then connects to the WiFly device with an emulated 2s delay.

2.7 Power Supply

The function of the power supply system is to a desired energizing current, accordingto a reference current signal, to a load or group of load elements in the most efficientand dependable method. Depending on specific circumstances, a power regulation systemcan be engineered with different objectives in mind. Some of the most important factorsconsidered during the design process of a power system circuit include; cost of manufacture,dependability, weight and mass. Numerous variants come into consideration when designing

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a power circuit for components that require different power requirements. The challengecomes with implementing the correct power source adequately to each component in themost efficient manner. In order to satisfy the power requirements of our robot two 37 Vsources connected in parallel will be implemented in our power circuit to provide sufficientpower to our Motors excavation system. Originally the team intended to implement aswitching regulator to step down the voltage in order to comply with the MCU requirementsince it requires a much lower voltage. However when I approached our senior advisorwith the design in mind, it was recommended to separate the MCU to a dedicated powersource. The reason for this is that switching regulators are not very dependable and asingle spike could cause the MCU to reset during operation which could potentially ruinour performance. One of the initial decisions that were covered during the design portionof the power regulation system was the battery source. A large set of options were availablehowever our specifications narrowed it down to three types of batteries: Lithium-Ion :Lightweight, comparatively expensive, fast charge with zero memory effect. Lead Acid :Large and heavy, comparatively inexpensive, high current output. Lithium-polymer -Similarto Lithium-Ion with higher current output but less energy density. The optimal choice forweight minimization is to use lithium-polymer or lithium- Ion Batteries. Although cost isour greatest limiting factor at the time it was essential in order to qualify that we meet theweight requirement. Therefore we selected a lithium-polymer battery that only weighs 5lb,we plan to include two in our design.

2.8 Sensors

We plan to implement sensors throughout robot to provide the robotic device with themeans of making automatic decisions within their environment. In order to accomplish thisgoal the robotic device is going to require a collection of sensors. Without sensors, a robotcould not detect respond to changes within their environment making it unadoptable. Asensor is a device that measures physical quantities and converts it into a signal which canbe read by an observer or by an instrument.

Types of Sensorso Position, angle, displacement, distance, speed, accelerationo Acoustic, sound, vibrationo Navigation instrumentso Optical, light, imagingo Proximity, presenceo Electric current, magnetic, radio, voltageo Pressure, force, density, levelAll of these components will assist the operator for better maneuvering, as well to collect

data to record performance specifications using these sensors. Telerobotic operators will beable to observe the Lunarena through fixed overhead cameras on the Lunarena throughmonitors that will be provided by NASA in the Mission Control Room.

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CHAPTER 3

FINAL DESIGN

The final design for the Hexcavator centers around a hexapedal running and walking base.Mounted on top of this base is the excavation hardware. We use a modified bucket chainexcavation system that swivels forward when excavating. The regolith will be offloadedusing a pulley lift system. The electronics will be mounted directly to the base frame.

Figure 3.1: : Final Design

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3.1 Locomotion Design

To preclude some of the complications associated with developing a robot that usesa legged mode of locomotion, we implemented dynamic scaling to determine the maindimensions of our robot. We scaled the original RHex robot up to 60 kg for our purposes.This dimension defined all other relations of the robot, such as the length and stiffness ofits legs and the dimensions of the frame. From these dimensions, we were able to specifywhich power transmission components were required for our locomotion system. The RHexuses an alternating tripod gait as its main method of locomotion, as shown in Figure ?? .Dynamic scaling placed the diameter of the semi-circular legs for the large RHex at 29.7cm. To determine the continuous torque required for the motor, we used the peak torque ofthe predicted gait as a conservative overestimate. Additional conservatism was introducedmy assuming the mass of the robot to be 70 kg instead of the dynamically scaled 60 kgand by assuming a large leg touchdown angle of 40 degrees. The required torque of eachmotor is therefore found to be 43.7 Nm for a static case. In order to account for dynamicparameters, this torque was scaled up to 70 Nm peak. The dynamically scaled speed of therobot puts the stride frequency at 1.46 Hz.

Figure 3.2: : The SLIP Model of the RHex [14]

From these specifications we determined that the motor we needed was a Maxon RE65geared down 50:1. This motor was selected because it has the highest power density ofall motors that we found, and the Maxon brand has been shown in the STRIDe Lab toperform robustly outside its specification range. Even though this motor has the highestpower density out of all the motors, we needed even more power out of it. We will berunning our motors at 36V to get the power that we need to move this robot. The currentdraw from each motor operating at these conditions is 35A. This will reduce the lifespan ofmost motors, but the Maxon motors have shown extraordinary durability when run at morethan twice the recommended voltage in the STRIDe Lab. Due to the space constraints ofthe competition, we need to use right angle gearboxes. We found the lightest and mostcompact right angle gearbox capable of tolerating the torque loads that we will be inflictingon it is the UTR006 from Thomson Micron. A datasheet for the gearbox and one for themotor can be found in the appendix. The RHex implements a control scheme for runningand walking locomotion called The Buehler Clock which is shown in Figure ??. The BuehlerClock consists of a slow stepping phase while the leg is touching the ground as representedby the section of the graph with the lower slope. This slow stepping phase is followed bya quick resetting phase, denoted by the higher slope on the graph. The four parameters

18

governing this clock, the liftoff and touchdown angles and the time taken for each section,determine the locomotion performance of the robot.

Figure 3.3: : The Buehler Clock [14]

In order to precisely control the position, velocity and acceleration of the leg, we need touse a position sensor. The Maxon encoder that comes attached to the motor is more thansufficient for this purpose. Reading encoders is a very intensive process from an electronicsperspective. Considering this, we have chosen a motor driver that can implement closedloop PID control of our motors by reading an encoder. The Roboteq HDC2450 is a motorcontroller capable of controlling two motors at once while simultaneously reading theirencoder values. It can provide 100A to each motor at 50V, power specifications well in theclear of our uses. The microcontroller interfaces with these motor controllers through serialRS-232 communication. By using this communication, we can read the current sensors thatare integrated into the controller, as well as the internal temperature of the controller andthe current state of each leg. This information will prove crucial for fine tuning our gaitparameters safely when we begin testing. When analyzing the RHex, its legs are treated asequivalent linear springs. The stiffness of these springs is found from dynamic scaling. Thestiffness of the legs is the largest determinant for the locomotion performance of the robot.The scaled stiffness for each leg is 15,905 N/m. By implementing a reduced order modelcalled the Pseudo-Rigid Body Model, shown in Figure ??, we can determine the requireddimensions of the composite legs for the RHex. These legs will be made from 12k IM-7Carbon Fiber with a vinyl ester matrix. Material testing for this composite has put theelastic modulus around 70 GPa. The width of the legs was set at the highest possible valueof nine cm each to increase traction. By modeling the leg as an equivalent structure of rigidbeams with flexure joints, the thickness required for the leg is predicted to be 5.18mm.

To confirm this prediction, we used a FEM simulation with a fixed upper section of theleg and a vertical 1kN load on the tip of the leg. The maximum vertical deflection, shownin Figure ?? was 65.93mm, giving an equivalent stiffness of 15,167 N/m, an error of only4.6

19

Figure 3.4: : The Pseudo-Rigid Body Model [15]

Figure 3.5: : FEM Analysis of the RHex leg

20

3.2 Chassis Design

The final design of the chassis uses Aluminum 6063 three-quarter inch square tubingand quarter inch plate. The projected mass of the subsystem is 5.3 kilograms and will allowfor the gearbox output shaft to connect directly to each leg. As shown in Figure ??, aFinal Element Analysis Simulation of the chassis shows a maximum deflection of one (1)centimeter upon impacting a force twice the mass of the robot itself.

Figure 3.6: : FEA Simulation of the chassis undergoing vertical side loading

The chassis itself widens at the middle in order to properly mount the middle motorswithout having to extend the output shaft of the gearbox. This design also gives way tomore space within the center of the chassis for electronics and batteries. Finally, a carbonfiber shell will be placed around the chassis in order to prevent any regolith from interferingwith any electrical or mechanical components enclosed. The support frame of the regolithunloading subsystem will be mounted directly to the chassis while the excavation subsystemwill be attached to the carbon fiber shell.

3.3 Excavation and Offloading Design

In order to incorporate an excavation system onto our locomotion platform, the systemmust be tailored so that it is able to function properly without compromising the balanceand structural strength of the system frame. In order to accomplish this, a four-bar linkagewill be used as the mount for the bucket chain system. This will allow the bucket chainto move forward while the robot is traversing the course. By shifting the system forwardthe center of gravity is lowered closer to that of the platform itself which helps to minimizetipping and also allows for the unloading of the collected regolith. During the collectionprocess the weight of the excavator will apply pressure to the point at which it contactsthe surface of the regolith. As the regolith is collected and the surface is lowered relative

21

to the rest of the course, the weight of the system will automatically adjust the contactpoint to remain on the surface so that the volume of regolith and the rate at which it iscollected will remain uniform through out the process. Once the excavation system reachesthe compacted layer of the course which it will most likely be unable to penetrate; the entirerobot will shift forward slightly to a new area and collection can resume. This process willbe repeated until the bucket is full, at which point the robot will be returned to the startingarea to begin offloading the regolith.

3.4 Power Supply

This design consist of two 37 V batteries connected in parallel with an according emer-gency stop button which is a competition requirement. The first 3 Driver motor controllerswill operate the locomotion of the robot and the last one is to power the excavation system.We incorporated fuses to protect our electronics. As a safety measure, the MCU will runoff a separate source to prevent the potential reset if it was to be integrated in the mainsystem. The micro-controller has an output voltage of 5V that will be utilized to power thesensors.

Figure 3.7: : Main Power Supply Circuit Diagram

22

Figure 3.8: : MCU Circuit Diagram

23

CHAPTER 4

ACKNOWLEDGMENTS

The members of the HEXCAVATOR Project would like to thank all of the sponsors thatare helping make this project possible. Our funding is coming from a ESMD Space Grantfrom NASA and a generous donation from Northrup Grumman. We would also like tothank all of the manufacturers who have given us significant discounts: Thomson Micron,Maxon Motors, Texas Instruments, and Roboteq. We would also like to thank the STRIDeLab for the donation of working space and manufacturing equipment as well as invaluabletechnical assistance.

24

BIBLIOGRAPHY

[1] NASA. Nasa announces first lunabotics competition winners@ONLINE, June 2010.(document), 1.1

[2] Compact rugged light weight custom robots, 2010. (document), 2.1

[3] Clark J.E. Jun, J. Dynamic stability of variable stiffness running. (document), 2.2

[4] Kevin Galloway. Kevin galloway archive edubot@ONLINE, December 2010. (docu-ment), 2.3

[5] Discovery Communications. Prototype this: Six-legged atv@ONLINE, November 2008.(document), 2.4

[6] Patricia Korzec. Aircraft: Lockheed sr-71a blackbird@ONLINE, September 2010. (doc-ument), 2.5

[7] U.S. Navy. Equipment operator, basic, 1994. (document), 2.6

[8] Bucket wheel excavator, 1999. (document), 2.7

[9] Designs, 2009. (document), 2.8

[10] Mechanics: Work and simple machines. (document), 2.9

[11] Compact linear actuator, 2010. (document), 2.10

[12] Dk-lm3s9b96 development kit, 2010. (document), 2.11

[13] Wifly 802.11b serial module - roving networks, 2010. (document), 2.12

[14] J. Seipel and P. Holmes. A simple model for clock-actuated legged locomotion. (doc-ument), 3.2, 3.3

[15] Intro to compliant mechanisms, 2010. (document), 3.4

25

APPENDIX A

APPENDIX

A.1 Part Drawings

26

80

110

R8

55

40

15.9

2

30.9

2 30.9

215

.92

R2.8

6.35

PA

RT

NA

ME

:M

OTO

R M

OU

NT

PR

OJE

CT

NA

ME

HE

XC

AV

ATO

RD

RA

WN

BY

:W

ILLI

AM

FE

DO

RIW

DA

TE:

12/5

/10

0.75

0S

CA

LE

15

38

537691

48

104.

1

R17.

643

R7

R2.5

R2.5 R4

.5

5

DR

W :

She

et: 1

of 1

R

EV

: 0

DATE

:12/

7/10

By:Du

ncan H

aldan

e

PR

OJE

CT:

HE

XC

AV

ATO

R

PA

RT:

Mot

or A

dapt

er

1.00

0S

CA

LE

1538

53

76

69.3

42

76 R28

R2.5

15

1823

31.8

99

7.5

11.2

23

18.2

88

DR

W :

She

et: 1

of 1

R

EV

: 0

DATE

:12/

6/20

10By

:Dunca

n Hald

ane

PR

OJE

CT:

HE

XC

AV

ATO

R

PA

RT:

Gea

rbox

Ada

pter

1.00

0S

CA

LE

0,50

0S

CA

LE

0,75

0S

CA

LE

A.2 Data Sheets

38

Operating Range Comments

Continuous operationIn observation of above listed thermal resistance(lines 17 and 18) the maximum permissible windingtemperature will be reached during continuousoperation at 25°C ambient.= Thermal limit.

Short term operationThe motor may be briefly overloaded (recurring).

Assigned power rating

n [rpm]

max

onD

Cm

otor

maxon Modular System Overview on page 16 - 21

Specifications

84 maxon DC motor May 2010 edition / subject to change

Stock programStandard programSpecial program (on request)

Order Number

RE 65 �65 mm, Graphite Brushes, 250 Watt

353294 353295 353296 353297 353298 353299 353300 353301

Motor Data (provisional)Values at nominal voltage

1 Nominal voltage V 18.0 24 36 48 60 70 70 702 No load speed rpm 3400 3950 3840 3550 3570 3340 3090 26103 No load current mA 853 797 499 328 263 181 180 1484 Nominal speed rpm 3170 3700 3620 3340 3360 3130 2880 24005 Nominal torque (max. continuous torque) mNm 423 440 581 679 718 774 776 8326 Nominal current (max. continuous current) A 9.72 8.72 7.16 5.68 4.79 3.81 3.437 Stall torque mNm 14000 16200 18000 16600 16700 15500 14100 126008 Starting current A 296 292 207 131 106 78.6 66.1 49.79 Max. efficiency % 79 82 86 87 88 89 88 88

Characteristics10 Terminal resistance � 0.0609 0.0821 0.174 0.365 0.568 0.891 1.06 1.4111 Terminal inductance mH 0.0226 0.0308 0.076 0.161 0.251 0.393 0.458 0.64312 Torque constant mNm / A 47.5 55.4 87 127 158 198 214 25313 Speed constant rpm / V 201 172 110 75.4 60.4 48.3 44.7 37.314 Speed / torque gradient rpm / mNm 0.258 0.256 0.22 0.218 0.217 0.218 0.222 0.21015 Mechanical time constant ms 3.74 3.46 3.18 3.05 3 2.97 2.97 2.9416 Rotor inertia gcm2 1380 1290 1380 1340 1320 1310 1280 1340

Thermal data17 Thermal resistance housing-ambient 1.3 K / W18 Thermal resistance winding-housing 1.85 K / W19 Thermal time constant winding 127 s20 Thermal time constant motor 960 s21 Ambient temperature -30 ... +100°C22 Max. permissible winding temperature +125°C

Mechanical data (preloaded ball bearings)23 Max. permissible speed 5500 rpm24 Axial play at axial load < 25 N 0 mm

> 25 N 0.1 mm25 Radial play 0.03 mm26 Max. axial load (dynamic) 70 N27 Max. force for press fits (static) 420 N

(static, shaft supported) 12000 N28 Max. radial loading, 15 mm from flange 350 N

Other specifications29 Number of pole pairs 230 Number of commutator segments 2631 Weight of motor 2100 g

Values listed in the table are nominal.Explanation of the figures on page 49.

Industrial version with radial shaft seal ring(resulting in increased no-load current)

2506000

1000

2000

4000

1.5 3.0 4.5 6.0

150 300 450 600

353297

750

3000

5000

Planetary Gearhead�81 mm20 - 120 NmPage 244

Encoder HEDS 5540500 Imp.,3 channelsPage 267Encoder HEDL 5540500 Imp.,3 channelsPage 269

Recommended Electronics:ADS 50/5 Page 282ADS 50/10 283ADS_E 50/5 283ADS_E 50/10 283EPOS2 50/5 305EPOS2 70/10 305Notes 18

M 1:4

Industrial VersionIP54Encoder HEDL 9140Page 272Brake AB 44Page 321End capPage 322

IndustrialVersion

www.danahermotion.com84

1 Ratios are exact, higher ratios are also available, consult factory.Tr = Rated output torque at rated speed for specific hours of life.

Tpeak = Allowable momentary peak torque for emergency stop or heavy shock loading.J = Mass moment of inertia reflected to the input shaft (including pinion assembly).

All dimensions are: mm (inch)AD** = Adapter lengthAdapter length will vary depending on motor.M.S.= Mounting SurfaceEfficiency is calculated at 100% of the rated torque.

M

ø 16 k6

(.6304/.6300)

48

(1.89)

1

(.04)

25

(.98)

18

(.71)

AD*

ø 60 g6

(2.3618/2.3611)

18

(.709)

61 SQ.

(2.40)

ø 5.6 (.22) THRU HOLES

4PL EQUALLY SPACED ON A

ø 68 (2.68) BOLT CIRCLE

61 SQ.

(2.40)

1

(.04)

109

(4.30)

78.5

(3.10)

7

(.28)

5 h9

(.1969/.1957)

M5 THREAD X

19 (.75) DEEP

N

7

(.28) M.S

.

Metric

UltraTRUE 90™ Size 60

Helical Right Angle Gearheads

Ratio1

Dimension ‘M’

mm [in]

Dimension ‘N’

mm [in]

Backlash [arc-min]

Weightkg [lb]

Efficiency

1:1 to 5:1 86 [3.38] 55 [2.18] 4 max 2,5 [5.5] 98%

8:1 to 50:1 95 [3.75] 65 [2.55] 5 max 3 [6.6] 93%

Performance Specifications

Part Number

Ratio1

10,000 Hour Life

T peakNm [in-lb]

20,000 Hour LifeJ

kg-cm2

[in-lb-sec2x10-4]

Torsional StiffnessNm/arc-min

[in-lb/arc-min]

Tr(1000 rpm)

Nm [in-lb]

Tr(3000 rpm)

Nm [in-lb]

Tr(5000 rpm)

Nm [in-lb]

Tr(1000 rpm)

Nm [in-lb]

Tr(3000 rpm)

Nm [in-lb]

Tr(5000 rpm)

Nm [in-lb ]

UTR006-001 1:1 9 [77] 8 [70] 7 [64] 28 [247] 8 [71] 7 [65] 7 [59] ,97 [8.4] 2,1 [19]

UTR006-002 2:1 19 [170] 17 [155] 16 [140] 52 [456] 18 [157] 16 [143] 15 [129] ,50 [4.3] 3,2 [29]

UTR006-003 3:1 12 [108] 11 [99] 10 [89] 39 [342] 11 [100] 10 [91] 9 [82] ,43 [3.7] 3,6 [32]

UTR006-004 4:1 9 [80] 8 [73] 7 [66] 34 [301] 8 [73] 8 [67] 7 [61] ,40 [3.4] 3,8 [34]

UTR006-005 5:1 7 [65] 7 [60] 6 [54] 26 [228] 7 [60] 6 [55] 6 [50] ,39 [3.4] 3,9 [35]

UTR006-008 8:1 51 [447] 47 [413] 45 [394] 106 [938] 49 [438] 45 [397] 38 [340] ,50 [4.4] 2,1 [18]

UTR006-010 10:1 49 [433] 45 [401] 43 [384] 102 [906] 48 [423] 44 [392] 40 [355] ,49 [4.4] 1,8 [16 ]

UTR006-012 12:1 49 [432] 45 [394] 40 [356] 109 [961] 45 [399] 41 [364] 37 [329] ,39 [3.5] 2,0 [18]

UTR006-014 14:1 46 [411] 43 [383] 42 [368] 97 [860] 45 [402] 42 [374] 41 [360] ,49 [4.4] 2,4 [22]

UTR006-015 15:1 50 [443] 47 [413] 45 [397] 105 [927] 49 [433] 46 [404] 44 [388] ,39 [3.4] 2,4 [21]

UTR006-016 16:1 36 [318] 33 [290] 30 [262] 110 [975] 33 [294] 30 [268] 27 [242] ,39 [3.5] 2,4 [22]

UTR006-020 20:1 45 [398] 41 [363] 37 [328] 106 [939] 41 [367] 38 [335] 34 [303] ,39 [3.5] 2,4 [21]

UTR006-025 25:1 37 [326] 34 [298] 30 [269] 107 [948] 34 [301] 31 [275] 28 [249] ,38 [3.4] 2,3 [21]

UTR006-028 28:1 48 [427] 45 [401] 44 [388] 100 [887] 47 [417] 44 [392] 43 [379] ,39 [3.5] 2,2 [20]

UTR006-030 30:1 30 [266] 26 [232] 25 [217] 93 [822] 28 [246] 24 [215] 23 [201] ,42 [3.7] 2,3 [20]

UTR006-035 35:1 49 [432] 46 [407] 43 [377] 101 [894] 48 [422] 44 [385] 39 [348] ,38 [3.4] 2,3 [20]

UTR006-040 40:1 31 [275] 27 [240] 25 [225] 94 [830] 29 [255] 25 [223] 24 [208] ,39 [3.5] 2,4 [22]

UTR006-050 50:1 32 [283] 28 [247] 26 [232] 94 [836] 30 [262] 26 [229] 24 [215] ,38 [3.4] 2,4 [21]

A.3 Competition Rules

41

23 November 2010 Page 1

NASA’s Lunabotics Mining Competition

2011 Rules & Rubrics

November 23, 2010

Kennedy Space Center, Florida

Introduction

NASA’s Lunabotics Mining Competition is designed to promote the development of interest in space activities and STEM (Science, Technology, Engineering, and Mathematics) fields. The competition uses excavation, a necessary first step towards extracting resources from the regolith and building bases on the moon. The unique physical properties of lunar regolith and the reduced 1/6

th gravity, vacuum

environment make excavation a difficult technical challenge. Advances in lunar regolith mining have the potential to significantly contribute to our nation’s space vision and NASA space exploration operations. The competition will be conducted by NASA at Kennedy Space Center. The teams that can use telerobotic or autonomous operation to excavate the most lunar regolith simulant within a 15-minute time limit will win the competition. The minimum excavation requirement is 10.0 kg, and the excavation hardware mass limit is 80.0 kg. Winners are eligible to receive first, second, or third place awards of $5,000, $2,500, and $1,000, respectively. Undergraduate and graduate student teams enrolled in a U.S. or international college or university are eligible to enter the Lunabotics Mining Competition. Design teams must include: at least one faculty with a college or university and two or more undergraduate or graduate students. Teams will compete in up to five categories including: on-site mining, systems engineering paper, outreach project, slide presentation (optional), and team spirit (optional). Additionally, teams can earn bonus points toward the Joe Kosmo Award for Excellence multidisciplinary teams and collaboration between a majority and U.S. minority serving institutions earn. All documents must be submitted in English. Awards include monetary scholarships, a school trophy or plaque, individual certificates, KSC launch invitations, and up to $1,500 travel expenses for each team member and one faculty advisor to participate with the NASA Desert RATS as the winners of the Joe Kosmo Award for Excellence. Award details are available at www.nasa.gov/lunabotics. The Lunabotics Mining Competition is a student competition that will be conducted in a positive professional way. So this is a reminder to be courteous in your correspondence and on-site at the competition because unprofessional behavior or unsportsmanlike conduct will not be tolerated and will be grounds for disqualification.


Game Play Rules

1) These rules and specifications may be subject to future updates by NASA at its sole discretion.

2) Teams will be required to perform 1 official competition attempt using lunar regolith simulant, Lunarena and collector provided by NASA. NASA will fill the Lunarena with compacted lunar regolith simulant that matches as closely as possible to the lunar regolith described in the Lunar Sourcebook: A User's Guide to the Moon, edited by G. H. Heiken, D. T. Vaniman, and B. M. French, copyright 1991, Cambridge University Press. NASA will randomly place 3 obstacles and create 2 craters on each side of the Lunarena. Each competition attempt will occur with 2 teams competing at the same time, 1 on each side of the Lunarena. After each competition attempt, the obstacles will be removed, the lunar regolith simulant will be returned to a compacted state, and the obstacles will be returned to the Lunarena. See the Lunarena Diagrams on page 7.

3) In the official competition attempt, the teams that acquire (and deliver into the collector container) the first, second, and third most mass by excavating lunar regolith simulant over the minimum excavation requirement (10 kg) within the time limit (15 minutes) will respectively win first, second, and third place awards. In the case of a tie, the teams will compete in a head-to-head round, where the team that acquires the most lunar regolith simulant in that round wins.

4) All excavated mass deposited in the collector during the official competition attempt will be weighed after completion of the competition attempt. Any obstacles deposited in the collector will be removed from the lunar regolith simulant collected.

5) The excavation hardware shall be placed in the randomly designated starting zones. The order of teams will be randomly chosen throughout the competition.

6) A team’s excavation hardware shall only excavate lunar regolith simulant located in that team’s respective mining zone at the opposite end of the Lunarena from the team’s starting zone. The team’s exact starting point and traversal direction will be randomly selected immediately before the competition attempt.

7) The excavation hardware is required to move across the obstacle zone to the mining zone and then move back to the collector box to deliver the simulant into the collector box. See the Lunarena Diagrams on page 7.

8) Each team is responsible for placement and removal of their excavation hardware onto the lunar regolith simulant surface. There must be 1 person per 23 kg of mass of the excavation hardware, requiring 4 people to carry the maximum allowed mass. Assistance will be provided if needed.

9) Each team is allotted a maximum of 10 minutes to place the excavation hardware in its designated starting position within the Lunarena and 5 minutes to remove the excavation hardware from the Lunarena after the 15-minute competition attempt has concluded.

10) The excavation hardware operates during the 15-minute time limit of the competition attempt. The 15-minute time limit will be reduced if a team is not ready at the team’s competition attempt start time. Time will start even if a team is still setting up their excavator after the 10 minute setup time period has elapsed. The competition attempt for both teams in the Lunarena will end at the same time.

11) The excavation hardware will end operation immediately when the power-off command is sent, as instructed by the competition judges.

12) The excavation hardware cannot be anchored to the lunar regolith simulant surface prior to the beginning of the competition attempt.

13) Each team will be permitted to repair or otherwise modify the excavation hardware after the team’s practice time. The excavation hardware will be inspected the evening before the competition takes place and quarantined until just before the team’s competition attempt. Batteries will not be quarantined and may continue to charge.


Field Rules

14) At the start of the competition attempt, the excavation hardware may not occupy any location outside the defined starting zone. At the start of each competition attempt the starting location and direction will be randomly determined.

15) The collector box top edge will be placed so that it is adjacent to the side walls of the Lunarena without a gap and the height will be approximately 1 meter from the top of the simulant surface directly below it. The collector top opening will be 1.65 meters long and .48 meters wide. See the Lunarena Diagrams on page 7. A target may be attached to the collector for navigation purposes only. This navigational aid must be attached during the setup time and removed afterwards during the removal time period. The mass of the navigational aid is included in the maximum excavation hardware mass limit of 80.0 kg and must be self-powered.

16) There will be 3 obstacles placed on top of the compressed lunar regolith simulant surface within the obstacle zone before the competition attempt is made. The placement of the obstacles will be randomly selected before the start of the competition attempt. Each obstacle will have a diameter of approximately 20 to 30 cm and an approximate mass of 7 to 10 kg. Obstacles placed in the collector will not be counted as part of the excavated mass. There will be 2 craters of varying depth and width, being no wider or deeper than 30cm. No obstacles will be intentionally buried in the simulant by NASA, however, simulant includes naturally occurring rocks.

17) Excavation hardware must operate within the Lunarena: it is not permitted to pass beyond the confines of the outside wall of the Lunarena and the collector during the competition attempt. The regolith simulant must be collected in the mining zone allocated to each team and deposited in the collector. The team may only dig in its own mining zone. The simulant must be carried from the mining zone to the collector by any means. The excavator can separate intentionally, if desired, but all parts of the excavator must be under the team’s control at all times. Any ramming of the wall may result in a safety disqualification at the discretion of the judges. A judge may disable the excavator by pushing the red emergency stop button at any time.

18) The excavation hardware must not push lunar regolith simulant up against the wall to accumulate lunar regolith simulant.

19) If the excavation hardware exposes the Lunarena bottom due to excavation, touching the bottom is permitted, but contact with the Lunarena bottom or walls cannot be used at any time as a required support to the excavation hardware. Teams should be prepared for airborne dust raised by either team during the competition attempt.

Technical Rules

20) During the competition attempt, excavation hardware is limited to autonomous and telerobotic operations only. No physical access to the excavation hardware will be allowed during the competition attempt. In addition, telerobotic operators are only allowed to use data and video originating from the excavation hardware. Visual and auditory isolation of the telerobotic operators from the excavation hardware in the Mission Control Room is required during the competition attempt. Telerobotic operators will be able to observe the Lunarena through fixed overhead cameras on the Lunarena through monitors that will be provided by NASA in the Mission Control Room. These monitors should be used for situational awareness only. The Lunarena will be outside in an enclosed tent.

21) Mass of the excavation hardware shall not exceed 80.0 kg. Subsystems on the excavator used to transmit commands/data and video to the telerobotic operators are counted towards the 80.0 kg mass limit. Equipment not on the excavator used to receive commands from and send commands to the excavation hardware for telerobotic operations is excluded from the 80.0 kg mass limit.

22) The excavation hardware must be equipped with an easily accessible red emergency stop button (kill switch) of minimum diameter 5 cm on the surface of the excavator requiring no steps to access. The emergency stop button must stop excavator motion and disable all power to the excavator with 1 push motion on the button.


23) The communications rules used for telerobotic operations follow:

A. LUNABOT WIRELESS LINK

1. Each team will provide the wireless link (access point, bridge, or wireless device) to their Lunabot a. KSC will provide an elevated network drop (Female RJ-45 Ethernet jack) in the Lunarena

that extends to the control room, where we will have a network switch for the teams to plug in their laptops

i. The network drop in the Lunarena will be elevated high enough above the edge of the regolith bed wall to provide adequate radiofrequency visibility of the competition pit.

ii. A shelf will be setup next to the network drop and located 4 to 6 feet off the ground and will be no more than 50 feet from the Lunabot. This shelf is where teams will place their Wireless Access Point (WAP) to communicate with their rover.

iii. The WAP shelves for side A and side B of the regolith pit will be no closer than 25' from each other to prevent electromagnetic interference (EMI) between the units.

b. NASA will provide a standard 110VAC outlet by the network drop. Both will be no more than 2 feet from the shelf.

c. During setup time before the match starts the teams will be responsible for setting up their access point.

2. The teams must use the USA IEEE 802.11 b/g standard for their wireless connection (WAP and rover client) Teams cannot use multiple channels for data transmission. Encryption is not required but it is highly encouraged to prevent unexpected problems with team links. a. During a match, one team will operate on channel 1 and the other team will operate on

channel 11. b. The channel assignments will be made either upon check-in or a few weeks prior to the

event. 3. Each team will be assigned an SSID that they must use for their wireless equipment.

a. SSID will be “Team_##” b. Teams shall broadcast their SSID

4. Bandwidth constraints: a. There will not be a peak bandwidth limit. b. Teams will be awarded in some way for using the least amount of total bandwidth during

the timed and NASA monitored portion of the competition. c. The communications link is required to have an average bandwidth of no more than 5

megabits per second.

B. RF & COMMUNICATIONS APPROVAL

1. There will be a communications judge’s station where each team will have approximately 15 minutes to show the judges that their Lunabot & access point is operating only on their assigned channel.

2. To successfully pass the communications judge's station a team must be able to command their Lunabot (by driving a short distance) from their Lunabot driving/control laptop through their wireless access point. The judges will verify this and use the appropriate monitoring tools to verify that the teams are operating only on their assigned channel.

3. If a team cannot demonstrate the above tasks in the allotted time, they will be disqualified from the competition.

4. Each team will have an assigned time on Monday or Tuesday to show the judges their compliance with the rules.

5. The NASA communications team will be available to help teams make sure that they are ready for the judging station on Monday and Tuesday.

6. Once the team arrives at the judge’s station, they can no longer receive assistance from the NASA communications team.

7. If a team is on the wrong channel during a match, they will be required to power down and be disqualified from that match.


C. WIRELESS DEVICE OPERATION IN THE PITS

1. Teams will not be allowed to power up their transmitters on any frequency in the pits once the practice matches begin. All teams shall have a hard-wired connection for testing in the pits.

2. There will be designated times for teams to power up their transmitters when there are no matches underway.

24) The excavation hardware must be contained within 1.5m width x .75m length x 2m height. The hardware may deploy beyond the 1.5 m x .75 m footprint after the start of the competition attempt, but may not exceed a 2 meter height. The excavation hardware may not pass beyond the confines of the outside wall of the Lunarena and the collector during the competition attempt to avoid potential interference with the surrounding tent. The team must declare the orientation of length and width to the inspection judge. Because of actual lunar hardware requirements, no ramps of any kind will be provided or allowed.

25) To ensure that the excavation hardware is usable for an actual lunar mission, the excavation hardware cannot employ any fundamental physical processes (e.g., suction or water cooling in the open lunar environment), gases, fluids or consumables that would not work in the lunar environment. For example, any dust removal from a lens or sensor must employ a physical process that would be suitable for the lunar surface. Teams may use processes that require an Earth-like environment (e.g., oxygen, water) only if the system using the processes is designed to work in a lunar environment and if such resources used by the excavation hardware are included in the mass of the excavation hardware.

26) Components (i.e. electronic and mechanical) are not required to be space qualified for the lunar vacuum, electromagnetic, and thermal environments.

27) The excavation hardware may not use any process that causes the physical or chemical properties of the lunar regolith simulant to be changed or otherwise endangers the uniformity between competition attempts.

28) The excavation hardware may not penetrate the lunar regolith simulant surface with more force than the weight of the excavation hardware before the start of the competition attempt.

29) No ordnance, projectile, far-reaching mechanism, etc. may be used (excavator must move on the lunar regolith simulant).

30) No excavation hardware can intentionally harm another team’s hardware. This includes radio jamming, denial of service to network, regolith simulant manipulation, ramming, flipping, pinning, conveyance of current, or other forms of damage as decided upon by the judges. Immediate disqualification will result if judges deem any maneuvers by a team as being offensive in nature. Erratic behavior or loss of control of the excavation hardware as determined by the judges will be cause for immediate disqualification.

31) Teams must electronically submit documentation containing a description of the excavation hardware, its operation, potential safety hazards, a diagram, and basic parts list.

32) Teams must electronically submit video documentation containing no less than 30 seconds of excavation hardware operation and at least 1 full cycle of operation. One full cycle of operations includes excavation and depositing material. This video documentation is solely for technical evaluation of the team’s excavation hardware.

Video specifications:

Formats/Containers: .avi, .mpg, .mpeg, .ogg, .mp4, .mkv, .m2t, .mov; Codecs: MPEG-1, MPEG-2, MPEG-4 (including AVC/h.264), ogg theora; Minimum frame rate: 24 fps; Minimum resolution: 320 x 240 pixels


Definitions Black Point-1 (BP-1) – A crushed lava aggregate with a natural particle size distribution similar to that of lunar soil. The aggregate will have a particle size and distribution similar to the lunar regolith as stated in the Lunar Sourcebook: A User's Guide to the Moon, edited by G. H. Heiken, D. T. Vaniman, and B. M. French, copyright 1991, Cambridge University Press. Teams are encouraged to develop or procure simulants based on lunar type of minerals and lunar regolith particle size, shape, and distribution.

Collector – A device provided by NASA for the competition attempt into which each team will deposit excavated regolith simulant. The collector will be large enough to accommodate each team’s excavated regolith simulant. The collector will be stationary and located adjacent to the Lunarena. Excavated regolith simulant mass will be measured after completion of the competition attempt. The collector mass will not be counted towards the excavated mass or the mass of the excavation hardware. The collector will be 1.65 meters long and .48 meters wide. The collector walls will rise to an elevation of approximately 1 meter above the BP-1 surface directly below the collector. See the Lunarena Diagrams on page 7.

Competition attempt – The operation of a team’s excavation hardware intended to meet all the requirements for winning the competition by performing the functional task. The duration of the competition attempt is 15-minutes.

Excavated mass – Mass of the excavated lunar regolith simulant delivered to the collector by the team’s excavation hardware during the competition attempt, measured in kilograms (kg) with official result recorded to the nearest one tenth of a kilogram (0.1 kg).

Excavation hardware – Mechanical and electrical equipment, including any batteries, gases, fluids and consumables delivered by a team to compete in the competition.

Functional task – The excavation of regolith simulant from the Lunarena by the excavation hardware and deposit from the excavation hardware into the collector box.

Minimum excavation requirement – 10.0 kg is the minimum excavated mass which must be met in order to qualify to win the competition.

Power – All power shall be provided by a system onboard the excavator. No facility power will be provided to the excavator. There are no power limitations except that the excavator must be self-powered and included in the maximum excavation hardware mass limit of 80.0 kg.

Practice time – Teams will be allowed to practice with their excavators in the Lunarena. NASA technical experts will offer feedback on real-time networking performance during practice attempts.

Reference point – A fixed location on the excavation hardware that will serve to verify the starting location and traversal of the excavation hardware within the Lunarena. An arrow on the reference point must mark the forward direction of the excavator in the starting position configuration. The judges will use this reference point and arrow to orient the excavator in the randomly selected direction and position.

Lunabot – A teleoperated robotic excavator in NASA’s Lunabotics Mining Competition.

Lunarena – An open-topped container (i.e., a box with a bottom and 4 side walls only), containing regolith simulant, within which the excavation hardware will perform the competition attempt. The inside dimensions of the each side of the Lunarena will be 7.38 meters long and 3.88 meters wide, and 1 meter in depth. A dividing wall will be in the center of the Lunarena. The Lunarena for the official practice days and competition will be provided by NASA. See the Lunarena Diagrams on page 7.

Telerobotic – Communication with and control of the excavation hardware during the competition attempt must be performed solely through the provided communications link which is required to have a total bandwidth of no more than 5.0 megabits/second on all data and video sent to and received from the excavation hardware.

Time Limit – The amount of time within which the excavation hardware must perform the functional task, set at 15 minutes; set up excavation hardware, set at 10 minutes; and removal of excavation hardware, set at 5 minutes.


Lunarena Diagrams

Lunarena Diagram (side view)

Lunarena Diagram (top view)


Lunabotics Systems Engineering Paper

Each team must submit a Systems Engineering Paper electronically in PDF by April 18, 2011. Cover page must include: team name, title of paper, full names of all team members, university name and faculty advisor’s full name. Appendices are not included in the page limitation and the judges are not obligated to consider lengthy appendices in the evaluation process. A minimum score of 15 out of 20 possible points must be achieved to qualify to win in this category. In the case of a tie, the judges will choose the winning Systems Engineering Paper. The judges’ decision is final. The team with the winning Systems Engineering Paper will receive a team plaque, individual certificates, and a $500 scholarship.

Lunabotics Systems Engineering Paper Scoring Rubric

Elements 4 3 2 1

Content:

Formatted professionally, clearly organized, correct grammar and spelling, 10 – 15 pages; 12 font size; single spaced.

Cover page

Introduction

Purpose

Sources

All five elements are clearly demonstrated

Four elements are clearly demonstrated

Three elements are clearly demonstrated

Two or less elements are clearly demonstrated

Intrinsic Merit:

Deliverables identified

Budget

Schedule

Major reviews: system requirements, preliminary design and critical design

Illustrations support the technical content





Technical Merit:

Concept of operations

System Hierarchy

Basis of design

Interfaces defined

Requirements definition

Design margins

Trade-off assessment

Risk assessment

Reliability

Verification

Requirement flow-down to validation and checkout

Use of system life cycle

One point for each element clearly demonstrated up to twelve points.


Lunabotics Outreach Project

All teams must participate in an educational outreach project. Outreach examples include actively participating in

school career days, science fairs, technology fairs, extracurricular science or robotic clubs, or setting up exhibits in

local science museums or a local library. Other ideas include organizing a program with a Boys and Girls Club, Girl

Scouts, Boy Scouts, etc. Teams are encouraged to have fun with the outreach project and share knowledge of

science, robotics and engineering with the local community.

Each team must submit a report of the Lunabotics Outreach Project electronically in PDF by April 18, 2011. Cover

page must include: team name, title of paper, full names of all team members, university name and faculty advisor’s

full name. A minimum score of 15 out of 20 possible points must be achieved to qualify to win in this category. In the

case of a tie, the judges will choose the winning outreach project. The judges’ decision is final. The team with the

winning outreach project will receive a team plaque, individual certificates, and a $500 scholarship.

Lunabotics Outreach Project Scoring Rubric

Elements 4 3 2 1

Content:

Introduction

Outreach recipient group identified

Purpose

Cover page

All four elements

are clearly

demonstrated

Three elements

are clearly

demonstrated

Two elements

are clearly

demonstrated

One element is

clearly

demonstrated

Educational Outreach:

Inspires others to learn about robotics, engineering or lunar activities

Engages others in robotics, engineering or lunar activities

Utilizes hands-on activities

All three elements are clearly demonstrated

Two elements are clearly demonstrated

One element is clearly demonstrated

No elements are clearly demonstrated

Creativity:

Inspirational

Engaging

Material corresponds to audience’s level of understanding





Illustrations and Media:

Appropriate

Demonstrates the outreach project

Pictures





Formatting and Appearance:

Correct grammar and spelling

Five-page limit (cover page and appendices excluded in page count)

Clearly organized






Lunabotics Slide Presentation

Must be submitted electronically by April 18, 2011 in PDF. The Lunabotics Slide Presentation is an optional category

in the overall competition. A cover slide must contain the team name, title of presentation, full names of all team

members, university name and faculty advisor’s full name. A minimum score of 15 out of 20 possible points must be

achieved to qualify to win in this category. In the case of a tie, the judges will choose the winning presentation. The

judges’ decision is final. The team with the winning presentation will receive a team plaque, individual certificates, and

a $500 scholarship.

Lunabotics Slide Presentation Scoring Rubric

Elements 4 3 2 1

Content:

Cover slide

Introduction

Purpose

Stand alone – presentation will be judged prior to the competition without the benefit of a presenter

Sources referenced





Technical Merit:

Final Lunabot design

Design process

Design decisions

Lunabot functionality

Safety features

Special features

All six elements are clearly demonstrated

Five elements are clearly demonstrated



Creativity:

Innovative

Inspirational

Engaging





Illustrations and Media:

Appropriate

Supports the technical content

Shows progression of project

Clearly presents design of excavator

All four elements are clearly demonstrated




Formatting and Appearance:

Proper grammar

Correct spelling

Readable

Aesthetically pleasing

All four elements are clearly demonstrated





Lunabotics Team Spirit Competition

The Lunabotics Team Spirit Competition is an optional category in the overall competition. A minimum score of 10 out

of 15 possible points must be achieved to qualify to win in this category. In the case of a tie, the judges will choose

the winning team. The judges’ decision is final. The team winning the Team Spirit Award at the Lunabotics Mining

Competition will receive a team plaque, individual certificates, and a $500 scholarship.

Lunabotics Team Spirit Competition Scoring Rubric

Elements 3 2 1

Teamwork:

Exhibits teamwork in and out of the Lunarena

Exhibits a strong sense of collaboration within the team

Supports other teams with a healthy sense of competition

All three elements are

clearly demonstrated

Two elements are


One element is


Attitude:

Exudes a positive attitude

Demonstrates an infectious energy

Motivates and encourages team



Two elements are


One element is


Creativity:

Demonstrates creativity

Wears distinctive team shirts or hats

Gives out objects of fun, such as pins, noise makers, etc.



Two elements are


One element is


Engage:

Engages audience in team spirit activities

Engages other teams in team spirit activities

Makes acquaintances with members of other teams



Two elements are


One element is


Originality:

Demonstrates originality in team activities

Displays originality in the team name

Displays originality in the team logo



Two elements are


One element is



Categories for Bonus Points

Collaboration between a majority school with a designated United States Minority Serving Institution

The collaboration between a majority school and a designated U.S. minority serving institution (MSI) must be

identified by March 7, 2011 to receive 10 bonus points. MSI student team members must be indicated on the team

roster. A list of U.S. minority serving institutions may be found at: http://www2.ed.gov/about/offices/list/ocr/edlite-

minorityinst.html. Transcripts must be electronically submitted with the team roster by March 7, 2011.

Multidisciplinary Engineering Teams

Each different science, technology, engineering or mathematics (STEM) discipline represented will count for one

bonus point up to a maximum of 10. Disciplines will be indicated on the team roster by March 7, 2011. No bonus

points will be given in this category if a team has only one discipline represented. If a member of your team is in a

STEM discipline that is not on this list, you may e-mail [email protected] to request approval of that

discipline for the competition.

Aeronautical Engineering

Aerospace Engineering

Astrobiology

Astronautical Engineering

Astronomy

Astrophysics

Atmospheric Sciences

Bacteriology

Biochemistry

Biology

Biophysics

Chemical Engineering

Chemistry

Civil Engineering

Computer Engineering

Computer Science

Electrical Engineering

Engineering Management

Environmental Engineering

Geography

Geosciences

Health Engineering

Industrial/Manufacturing Engineering

Information Technology

Materials/Metallurgical Engineering

Mathematics

Mechanical Engineering

Microbiology

Natural Resource Management

Nuclear Engineering

Oceanography

Optics

Physics

Software Engineering

Systems Engineering


Lunabotics Checklist Required Competition Elements If required elements are not received by the due dates, then you are not eligible to compete in any part of the competition (NO EXCEPTIONS).

Registration February 28, 2011

Systems Engineering Paper April 18, 2011

Outreach report April 18, 2011

Optional Competition Elements Late presentations will not be accepted as part of the presentation competition, but the team is eligible to compete in all other parts of the competition and can make a presentation on site.

Presentation April 18, 2011

Team Spirit (on-site) May 23-28, 2011

Required Documentation

Registration February 28, 2011

Team Roster including March 7, 2011 o Participant information o Transcripts (unofficial copy is acceptable) o Media Release Form

Team Picture May 3, 2011

Team Biography (250-500 words) May 3, 2011

Head Count Form May 3, 2011

Team 19 Final Report

Documents

Transcript of Team 19 Final Report