Design and Implementation of a Speedometer and Speed Controller for Radio-controller Cars

Design and Implementation of a Speedometer and Speed Controller for Radio-controller Cars

Zhenyuan Yuan (Jack)Department of Electrical Engineering, University ParkCo-author: Nurali ViraniSupervisor: Dr. Minghui Zhu

This work is supported by Networked Robotic Systems Laboratory, University Park, from Department of Mechanical and Nuclear Engineering.

CERS 2016 Presentation

Present the work have done with Nurali, under supervision of Design and implement a speed monitoring and regulation system for radio-controlled car1

The future of autonomous drivingGoogle, Bosch, Audi, TESLA etc.Onboard motion planningReal time path following[1]http://o.aolcdn.com/hss/storage/midas/2b607a78e759755e5ec7beca39ef3149/201287542/google-self-driving-car-complete-prototype.jpg[2] http://images.hgmsites.net/hug/bosch-autonomous-car-technology_100417251_h.jpg[3] http://www.electronicproducts.com/uploadedImages/Electromechanical_Components/Motors_and_Controllers/fajb_tesla_lounge_02_feb2014.jpg

Googles autonomous car (source:[1])

Boschs autonomous car (source: [2])

TESLAs autonomous car model (source: [3])

Recent research on autonomous carOnboard motion planning, plan path, parking, lane switchingCapability of following, achieve autonomy2

Motion planning researchPath generated by motion planning algorithm as a series of checkpointsWe assume that the path is given.Path following control is the objective of this project.

[1] https://i.ytimg.com/vi/P8nOupnKZts/maxresdefault.jpgTypical motion plan (source: [1])Path: Checkpoints:

In our lab, motion planning algorithm, research topicFor example in the figure, path is planned as a series check points that the car needs to followValidate motion planning algorithm, experiment with the lowest cost and the simplest infrastructureChoose RC car, cost effective and obeys simple car dynamics3

Why do we use Radio-controlled (RC) Cars?

Well-suited for testing in lab environment [1]: http://www.redcatracing.com/IMG_7527.jpgObeys car dynamicsLacks the speed monitoring system

Validation on small-scale embedded platformsObey simple car dynamicsEasily implemented in our lab experimentBut lack of speed control system, thats why we need to build a speed monitoring and regulation system4

Objective of the projectThis project is focusing on the speed control by building a speed monitoring and regulation systemExisting method: Camera as visual odometry [1] Real-time Kinematic Global Position System (RTK-GPS) [2][1] Navid Nourani-Vatani, Jonathan Roberts, and Mandiam V Srinivasan. Practical visual odometry for car-like vehicles. In Robotics and Automation, 2009. ICRA09. IEEE International Conference on, pages 35513557. IEEE, 2009.[2] Chang Boon Low and Danwei Wang. Integrated estimation for wheeled mobile robot posture, velocities, and wheel skidding perturbations. In Robotics and Automation, 2007 IEEE International Conference on, pages 23552360. IEEE, 2007.

Path following control is composed of speed control and steering controlThere are existing method for speed control, such as .(indoor GPS)Neither of these is applicable due to the environmental constraint in our lab.

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Control system block diagramOUTPUTINPUT System

feedbackDisturbanceControllerSensing System

PID CONTROLLER

Hall-effect sensors

User input, controller generates command, system output, sensing system measures and feedback , adjusts output to match inputDisturbances, factors affect the outputTo be more specificSubsystem of the project, address in the coming slides6

From control input to actuationSpeed command actuation[1] https://hackadaycom.files.wordpress.com/2015/12/arduino-uno-wifi.png[2] http://www.robotshop.com/media/files/images/monster-motor-controller-shield-arduino-large.jpg

INPUT

Arduino Uno (source: [1])

Motor Driver (source: [2])PWMMOVEBluetooth communicationfrom userDesiredSpeed

System of the carInput desired speed to ArduinoDigital signal (PWM) to motor driver7

Sensing systemHall-effect sensor working principleThe voltage difference across an electric conductor transverse to the flow current due to the orthogonal magnetic field

Hall-effect sensor working principle (source: [1])[1] http://www.electronics-tutorials.ws/electromagnetism/mag26.gif

Hall-effect sensor

Sensing systemHall-effect (Left Hand Rule)For Hall-effect sensor, applying this principle, it will have different voltage outputs corresponding to the detection of different magnetic pole.8

Setting up the Hall-effect Sensors[1] Ali Pearlman. Car differential, retrieved from http://web.mit.edu/2.972/www/reports/differential/differential-1.gif.

Hall-effect sensors setup (source: [1])

Applying this functionalityHall-effect sensor mountedFrequency of analog signal passed down to the arduino9

Oscilloscope (source: [1])Hall-effect sensor output signal

Hall-effect sensor output captured by oscilloscope when the wheels run at 100 cm/s.

Hall-effect sensor output captured by oscilloscope when the wheels run at 300 cm/s.

[1] http://www.rigolna.com/images/products/DS1074B.jpg

Sensors signal is measured by oscilloscopeSquare, Speed vs. frequency, period vs. revolution speed (Arduino)10

Speedometer ValidationMethodSpeed data displacement data Position data displacement data

Result plot

Experiment environment

Functionality of the sensors is tested by experiment.Room equipped with motion capture system, provides accurate position data.Collect speed data from Hall-effect sensorRecord position data from motion capture sysemTransform to displacement data, bring to comparisonAlign pretty well, effective speedometer11

PID Controller (Proportional-Integral-Derivative)OUTPUTINPUT Disturbance (battery voltage & friction)

feedbackHall-effect sensor speedometer

+-

As the task of speed monitoring is completed by Hall-effect sensors, now I am going to introduce the speed regulation system done by PID controller.PID controller stands forModify the output according to the feedback from sensorsShown on the figure, , applied to error, to maintain at desired speed output regardless of12

Demonstration of PID controlMaintain the car running at desired speed13

Completed milestone:The combination of Hall-effect sensor and PID controller provides effective speed monitoring and regulation.

Future milestone:Steering feedback control Onboard motion planningThe road ahead

As shown in the demonstrationOne of the two parts of path following is done, way to the second partOnboard motion planning using embedded onboard computer is the parallel process.Video of current project, follow the path without large deviation14

Thank You

This is the project Thank you for listeningQuestions?15