Biomimetic Crab

Team P11029: William Dwyer Joseph Mead Shaynae Moore Casey O’Connell

Agenda• Background

• BOM, CS Needs, ENG Specs

• Final Design Decisions• Deviations, Controls

• Materials and Manufacturing• Results• Future Work• Conclusions

Background/Review of NeedsRev #1.3

Engr. Spec. #

Customer Needs (description) System Importance

CS1 Device must use McKibben muscle technology Claw 5

CS2 Device must function underwaterUmbilical Cord Claw

Aesthetics5

CS3 Pinchers perform and mimic a crab’s pinching movement Claw 5

CS4 Crab’s wrist performs and mimics flexion and extension Claw 5

CS5 Must have thorough documentation Documentation 5

CS6 Single, unified umbilical cord attachment Umbilical Cord 3

CS7 Device gives overall impression of a crab Aesthetics 3

CS8Functionality of the device must be enabled through a

control system Control Interface3

CS9 Claws must operate independently of each other Claw 1

CS10 Pinching speed must be greater than wrist speed Claw 1

Background/Review of SpecsEngr.

Spec. # Specification (description) System Customer Specification

Unit of Measure

Marginal Value

Target Value

Comments/Status

ES1 length of umbilical cord Umbilical cord Single unified umbilical cord attachment ft 6 8 Long enough to reach bottom of tank

ES2 diameter of umbilical cord Umbilical cord Single unified umbilical cord attachment in < 2.5 <2.0 Depends on the # of airlines

ES3 flexibility of umbilical cord Umbilical cord Single unified umbilical cord attachment yes/no no yes Is it flexible enough to allow for movement of crab?

ES4 # of airlines in umbilical cord bundle Umbilical cord Single unified umbilical cord attachment # 10 7 Depends on whether robot walks or not

ES5 input pressure of McKibben Muscles Claw Device uses McKibben muscle technology Device must function underwater psi 40 60

ES6 output force of McKibben Muscles Claw

Device uses McKibben muscle technology Device must function underwater Pincher performs and mimics a crab's pinching movement. lb 5 10 Enough force to oppose resistance and move quickly

ES7 length of McKibben Muscles Claw

Device uses McKibben muscle technology Device must function underwater Pincher performs and mimics a crab's pinching movement. in 4 7 Length will vary based on range of positions

ES8 speed/velocity of pincher ClawSpeed must be greater than wrist speed Pincher performs and mimics a crab's pinching movement. cycles/min 60 80 1 cycle = open & close

ES9 range of motion of flexion Claw Crab's wrist preforms and mimics flexion and extension. degrees 45 90 angular displacement

ES10 speed/velocity of wrist movement ClawSpeed must be less than pincher speed Device gives overall impression of crab. cycles/min < pincher 30 1 cycle is moving from neutral to full deflection one way

ES11 incremements of motion ClawFunctionality of device must be enabled through a control system Device gives overall impression of a crab degrees 90 45 1 displacement in flexion or extension

ES12 height of chassis from ground surface. Body / Chassis Device gives overall impression of crab in -- --

ES13 weight of crab Body / Chassis Device gives overall impression of crab lb -- --

ES14 width of crab abdomen Body / Chassis Device gives overall impression of crab in -- --

ES15 height of legs Body / Chassis Device gives overall impression of crab in -- --

ES16 length of crab body Body / Chassis Device gives overall impression of crab in 8 10 Length specified to accommodate muscle length

ES17 # of legs Body / Chassis Device gives overall impression of crab # 3 4 Model has 3 sets of legs + set of claws and flippers

ES18 portability Body / Chassis Functionality of the device must be enabled through a control system yes/no yes yes Can it be moved from place to place easily by Dr. Lamkin Kennard ?

ES19 USERS MANUAL (assembly & operation)

Documentation / Control Interface

Must have thorough Documentation Functionality of the Device must be used through a control system time (hr) 1.25 hrs 1

ES20 USERS MANUAL (maintain & storage)

Documentation / Control Interface Must have thorough Documentation Functionality of the Device must be used through a control systemtime (min) 30 15

ES21 DECISION MAKING PROCESS (organized compilation)

Documentation / Control Interface Must have thorough Documentation Functionality of the Device must be used through a control systemyes/no yes yes

ES22 User interface to control device

Documentation / Control Interface

Functionality of the device must be enabled through a control system Claws must operate independently of each other # Commands 12 10

B.O.MItem Discription Size Quantity Related Component Vendor/Acquisition Method Cost

Abrasion-Resistant Clear Polyurethane Tubing 1/8" 25 ft Umbilical Cord McMaster-Carr $7.50Abrasion-Resistant Clear Polyurethane Tubing 1/16" 25ft Umbilical Cord McMaster-Carr $11.50

Stainless Steel Socket Head Cap Screw 4-40 Thread 1 Arm Assembly McMaster-Carr $4.00Stainless Steel Hex Nut 4-40 Thread 1 Arm Assembly McMaster-Carr $2.75Silicon Flexible Tubing 0.25" 10 ft Muscle Rubber MSC $8.50

Nickel-plated Brass Push-to-Connect 1/4" Fitting 5 Umbilical Mount McMaster-Carr $17.20Clear Polyureathane Tubing 1/16" ID 50 ft Umbilical Cord McMaster-Carr $11.50

Stainless Steel Screws Head Cap Screw 4-40 Thread 1 Body Assembly McMaster-Carr $7.50Stainless Steel Screws Flat Washer 18-8 1 Body Assembly McMaster-Carr $2.00Stainless Steel Screws Lock Washer 18-9 2 Body Assembly McMaster-Carr $0.87

316 Stainless Steel Thin Hex nut 7mm 1 Body Assembly McMaster-Carr $4.69Stainless Steel Extension Spring 1 1/4" 3/16" 1 Arm Assembly McMaster-Carr $10.02Stainles Steel Extension Spring 1 1/2" 5/16" 1 Arm Assembly McMaster-Carr $13.12

Abrasion-Resistant Clear Polyurethane Tubing 3/32" 25ft Umbilical Cord McMaster-Carr $7.50Spiral Cable Wrap 5 ft 1 Umbilical Cord RadioShack $4.99

Demonstration Kiddie Pools 3' , 5' 1 Environment Toys 'R' Us $21.98Clear Plastic Storage Container 32 Qt 1 Hardware Envelope Target $7.99

Rapid Prototype Leg Mounts Dwg 8 Leg Assembly Brinkman Lab -Rapid Prototype Leg Visor Dwg 1 Front Visor Brinkman Lab -

Gate Valves Solonids - 6 Controls Allocated by ME dept. -15 lb Fishing Line 15lb 2' Tendon Actuators Allocated by ME dept. -

2' x 2' Aluminum Sheet 1/8" Thck 1 Arm and Leg Assembly Allocated by ME dept. -Muscle Materials Various - Muscles Allocated by ME dept. -

Plastic Dowl .625" 2' Umbilical Assembly Allocated by ME dept. -Nickel Plated Brass Push-to-Connect 1/8" 12 Umbilical Assembly Allocated by ME dept. -

Velcro Adhesive 0.5" 1ft Shell Mount Allocated by ME dept. -Acrylic Mounting Bracket Dwg 1 Umbilical Mounting Bracket Allocated by ME dept. -

Acrylic Baseplate Dwg 1 Baseplate Allocated by ME dept. -Shell Custom 1 Shell Fine Line Prototyping $200.00

Total $143.61

Bill Of Materials

Final Design Deviations• Clear ShellGives the viewer a view to the mechanical aspects of our device

• Puncture to relieve air bubbles

• Fishing Wire 15lb test Line for tendons

• Gate valve solenoids

• Double bolting the forearms

• CAD Model Interface

• Brass washers to reduce friction

• Lock Washer Fittings

Final Design-ControlsLABVIEW CONTROLS• Both arms operate independently of each other.• On each hand two muscles pairing relationships can be

operated.

• Pinching can always be preformed in any wrist position

• Flexion and Extension are analog choices (one or the other)

• Pincher response is much quicker than wrist response.

Materials and ManufacturingVariety of Manufacturing Methods

• CNC• Acrylic Baseplate

• Laser Cut• Aluminum Legs• Claw Components

• Mill and Lathe• Umbilical Assembly• Mounting Bracket

• Rapid Prototyping• Brinkman Lab

• Visor & Mounting Brackets

• Fine Line Prototyping• Shell

Results – Above water

http://vimeo.com/20089892

Results - Underwater

http://vimeo.com/20089817

Future WorkSELF CONTAINED UNIT

FEEDBACK CONTROL

LOCOMOTION

COMPATABLE WITH BIOROBOTICS (EE) CLASS

ConclusionsTesting Observations

• Improved Performance in Water• Friction between the aluminum plates and clamps

appears to be lubricated and slides with ease

• Pincer cycling is faster than Wrist Cycling• Strength of springs affect resistance load.• Less mass to move in Pincher

• Repeatability Of muscles

• Useful application underwater!