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
Google’s autonomous car
(source:[1])
Bosch’s autonomous car
(source: [2])
TESLA’s 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. ICRA’09. IEEE International Conference on, pages 3551–3557.
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
2355–2360. 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

11. Speedometer Validation
Method
• Speed data  displacement
data
• Position data  displacement
data
Result plot
Experiment environment

12. PID Controller (Proportional-Integral-
Derivative)
OUTPUTINPUT
Disturbance (battery voltage & friction)
feedback
Hall-effect sensor
speedometer
Σ
P 𝐾 𝑝 𝑒(𝑡)
I 𝐾𝑖∫ 𝑒 𝑡 𝑑𝑡
D
𝐾 𝑑 𝑑𝑒 𝑡
𝑑𝑡
+
-
𝑒 𝑡 = 𝑣 𝑚𝑒𝑎𝑢𝑟𝑒𝑑 𝑡 − 𝑣 𝑑𝑒𝑠𝑖𝑟𝑒𝑑(𝑡)

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

15. Thank You 