This document summarizes a project to design and implement a speedometer and speed controller for radio-controlled cars. Hall-effect sensors are used to measure wheel speed and provide feedback to a PID controller, which regulates motor speed to match desired speed inputs. The system was validated using displacement and position data from experiments. Future work will integrate steering feedback control and onboard motion planning.
1 of 15
Download to read offline
More Related Content
CERS presentation
1. Design and Implementation of a Speedometer
and Speed Controller for Radio-controller Cars
Zhenyuan Yuan (Jack)
Department of Electrical Engineering, University Park
Co-author: Nurali Virani
Supervisor: Dr. Minghui Zhu
This work is supported by Networked Robotic Systems Laboratory, University Park, from Department of
Mechanical and Nuclear Engineering.
CERS 2016 Presentation
2. The future of autonomous driving
Google, Bosch, Audi, TESLA etc.
Onboard motion planning
Real 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])
3. Motion planning research
Path generated by motion planning
algorithm as a series of checkpoints
We assume that the path is given.
Path following control is the objective of
this project.
[1] https://i.ytimg.com/vi/P8nOupnKZts/maxresdefault.jpg
Typical motion plan (source: [1])
Path:
Checkpoints:
4. Why do we use Radio-controlled (RC) Cars?
Well-suited
for testing in lab
environment
[1]: http://www.redcatracing.com/IMG_7527.jpg
Obeys car
dynamics
Lacks the speed
monitoring system
5. Objective of the project
This project is focusing on the speed
control by building a speed
monitoring and regulation system
Existing 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
Speed control
Steering
control
6. Control system block diagram
OUTPUTINPUT System
feedback
Disturbance
Controller
Sensing
System
PID CONTROLLER
Hall-effect sensors
7. From control input to actuation
Speed 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])
PWM MOVE
Bluetooth
communication
from user
Desired
Speed
8. Sensing system
Hall-effect sensor working principle
The 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
9. 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])
10. 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
14. Completed milestone:
The combination of Hall-effect
sensor and PID controller provides
effective speed monitoring and
regulation.
Future milestone:
Steering feedback control
Onboard motion planning
The road ahead
#2: Present the work have done with Nurali, under supervision of
Design and implement a speed monitoring and regulation system for radio-controlled car
#3: Recent research on autonomous car
Onboard motion planning, plan path, parking, lane switching
Capability of following, achieve autonomy
#4: In our lab, motion planning algorithm, research topic
For example in the figure, path is planned as a series check points that the car needs to follow
Validate motion planning algorithm, experiment with the lowest cost and the simplest infrastructure
Choose RC car, cost effective and obeys simple car dynamics
#5: Validation on small-scale embedded platforms
Obey simple car dynamics
Easily implemented in our lab experiment
But lack of speed control system, thats why we need to build a speed monitoring and regulation system
#6: Path following control is composed of speed control and steering control
There are existing method for speed control, such as .(indoor GPS)
Neither of these is applicable due to the environmental constraint in our lab.
#7: User input, controller generates command, system output, sensing system measures and feedback , adjusts output to match input
Disturbances, factors affect the output
To be more specific
Subsystem of the project, address in the coming slides
#8: System of the car
Input desired speed to Arduino
Digital signal (PWM) to motor driver
#9: Sensing system
Hall-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.
#10: Applying this functionality
Hall-effect sensor mounted
Frequency of analog signal passed down to the arduino
#11: Sensors signal is measured by oscilloscope
Square, Speed vs. frequency, period vs. revolution speed (Arduino)
#12: Functionality of the sensors is tested by experiment.
Room equipped with motion capture system, provides accurate position data.
Collect speed data from Hall-effect sensor
Record position data from motion capture sysem
Transform to displacement data, bring to comparison
Align pretty well, effective speedometer
#13: 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 for
Modify the output according to the feedback from sensors
Shown on the figure, , applied to error, to maintain at desired speed output regardless of
#14: Demonstration of PID control
Maintain the car running at desired speed
#15: As shown in the demonstration
One of the two parts of path following is done, way to the second part
Onboard motion planning using embedded onboard computer is the parallel process.
Video of current project, follow the path without large deviation
#16: This is the project
Thank you for listening
Questions?