S22: TBD

Project Title

THE BEST DRIVER

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Abstract

Our goal for this project is to use knowledge we gathered from lectures to design, implement, and test a self-driving RC car using a Controller Area Network (CAN) bus for controller communication. The project involves FreeRTOS and utilizes periodic tasks (running at 1Hz, 10Hz, and 100Hz) to gather, process, and display data from various embedded modules.

Introduction

The project was divided into 5 modules:

• Sensor
• Motor
• Geo Controller
• Driver/LCD Controller
• Web Application

Team Members & Responsibilities

Gitlab Project Link - [1]

• Sensor
  • Jasdip Sekhon
  • Brian Ho
  • Justin Stokes

• Motor
  • Justin Stokes
  • Isaac Wahhab

• Geographical
  • Brian Ho
  • William Hernandez
  • Jasdip Sekhon

• Driver Logic & LCD & LED Ring
  • William Hernandez
  • Billy Lai
  • Isaac Wahhab

• Web Application & Communication Bridge Controller
  • Isaac Wahhab
  • Billy Lai

• Testing Team
  • The Best Driver Team

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Schedule

Week#	Start Date	End Date	Task	Status
1	02/15/2022	02/21/2022	Discussed sensors for prototyping, and reviewed previous projects.	Completed
2	02/22/2022	02/28/2022	Ordered Parts	Completed
3	03/01/2022	03/07/2022	Looking at potential options for additional sensors	Completed
4	03/08/2022	03/14/2022	Learning to use CAN BUSMASTER	Completed
5	03/15/2022	03/21/2022	Made prototype for project .dbc file	Completed
6	03/22/2022	03/28/2022	Discuss and learn how to use Eagle for PCB fabrication Modify projects/lpc40xx_shared_sconscripts to separate each node's periodic_callbacks files	Completed
7	03/29/2022	04/04/2022	Parts testing and prototyping Configure and integrate LSM303 as 3-D compass Initialize and configure GPS module Configure and test ultrasonic sensors	Completed
8	04/05/2022	04/11/2022	List hardware requirements for the PCB fabrication Start research on web application for interfacing with RC car Finalize GPS and sensor testing Verify sensor I2C addresses Debug GPS configuration and interfacing to acquire a GPS lock	Completed
9	04/12/2022	04/18/2022	PCB Design and meeting to validate design Design and review PCB prototype Get GEO messages and SENSOR messages to the DRIVER node Continue web application research Find a viable framework and IDE for development Test RC car interfacing Verify wheel control motor on the RC car (can move forward and reverse at various speeds) Verify steering control motor on the RC car (can steer left and right) Integrate GPS and sensors on the same CAN bus using different nodes Ultrasonic sensors tested and integrated with SENSOR node Integrate ESP32 to BRIDGE node Milestones: Detect an obstacle and command the RC car motor to stop	Completed
10	04/19/2022	04/25/2022	Order first PCB prototype Have a prototype for the web application Test BRIDGE node receiving data from web application Test interacting with the RC car wirelessly Test RC car wheel control from wireless control Test RC car steering control from wireless control Test LCD peripheral and output debug messages Configure and command LCD display Interface with wheel encoder Initial attempt to mount plexi-glass and boards to RC car MIA management for DRIVER node Verify consistent and reliable sensor values	Completed
11	04/26/2022	05/02/2022	Receive PCB from distributor Create a mount on the RC car to contain all the hardware Solder parts to PCB Fix unit tests for DRIVER, SENSOR, GEO, MOTOR nodes Integrate sensor values with driver logic Update motor steering on obstacles detected Update motor speed on obstacles detected Test PWM for RC car steering and motor movement Update DBC file for DRIVER_TO_MOTOR steering values (update from [-2, 2] steering range) Maintain GPS lock Verify GPGGA message is parsed correctly Validate GPS coordinates from GPS module GPS lock indication LED Finalize LCD display information Display current compass heading Display desired direction heading Display distance to destination MIA handling GEO handles GPS DESTINATION LOCATION MIA DRIVER handles SENSOR MIA and GEO STATUS MIA MOTOR handles DRIVER_TO_MOTOR_COMMAND message MIA	Completed
12	05/03/2022	05/09/2022	Handle Invalid NODE operation GEO compass with invalid i2c read_byte() GPS not locked, GPGGA message with invalid data SENSOR/BRIDGE with Wi-Fi bridge down Add LCD debug menu to replace analyzing BusMaster messages and remove printf() calls Clean up hardware Wire wrapping, mounting, sensor placements Power SJTwo Boards and peripheral from RC car battery using a buck converter Stabilize compass readings by callibrating LSM303 Test ESPs for Wi-Fi communication Test RPM wheel encoder sensor Mount wheel encoder to RC car Add RPM calculation code Verify RPM values are accurate Brainstorm collision logic for RC controller Handle case for stair obstacle Handle sensor data Ring LED interfacing Light up an LED for compass heading Light up an LED for destination heading	Completed
13	05/10/2022	05/16/2022	Test collision logic for RC controller Ensure external LED lights up when DRIVER logic is taking collision logic branch instead of driving towards destination Finalize the collision logic Validate SENSOR node Use ESP32 Wi-Fi modules to send destination location to SENSOR/BRIDGE node Test sensor readings given new sensor placements Validate GEO node Stabilize compass readings and ensure North, East, South, and West headings are accurate Validate destination_heading calculation Validate distance_to_destination calculation Verify specific GPS coordinates for waypoint locations at the parking garage Validate DRIVER node MIA handling for messages from GEO node and SENSOR node Validate MOTOR node Verify appropriate PWM signals are applied to RC car motor/steering on receiving motor commands from DRIVER node Update LCD screen to display debug information from DRIVER node Display current location and destination location Display RPM of wheels Design and implement waypoints algorithm to handle ramp (deadzone) on 6th floor of North Garage Turn off LED0-LED3 on all nodes after periodic_callbacks__initialize() function Use this feature to visually observe if the LEDs flash red during testing to indicate if a board is resetting unexpectedly	Completed
14	05/17/2022	05/25/2022	Finalize and test Ring LED Add North indication on ring LED Add party mode when destination is reached Checkpoint test: rotate the car in a 360 and verify the North LED indicator always points North Integrate and test waypoints algorithm Update mobile application Send destination coordinates to SENSOR node Expose debug messages to SENSOR node and then relay info to web app Emergency stop from web app Integrated headlights and taillights Headlights are always on Taillights are constantly on when the car is idle Taillights are flashing when car is reversing Integrate RPM in MOTOR node to adjust PWM for motor speed Reverse logic in DRIVER node when front sensors cannot be avoided Web app connected indication LED Adjust DRIVER_TO_MOTOR steer values to create smooth steering Final testing of full project Verify the SENSOR/BRIDGE node receives data from web application Verify the GEO node receives GPS destination from SENSOR/BRIDGE node Verify the DRIVER node receives GEO status messages Verify the DRIVER node receives SENSOR messages Verify the MOTOR node sends DBG command messages Verify waypoints algorithm by avoiding ramp area on 6th floor of North Garage Verify obstacle detection and reverse logic Finalize wiki report Video for Proj Wiki	Completed

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Parts List & Cost

Item#	Part Desciption	Vendor	Qty	Cost
1	RC Car	Redcat Racing [2]	1	$139.00
2	SJTwo Boards	SJTwo Boards On Amazon [3]	4	$200.00
3	CAN Transceivers (SN65HVD230)	Waveshare [4]	4	$40.00
4	LSM303 Triple-Axis Accelerometer and Magnetometer	Adafruit [5]	1	$15.00
5	Venus GPS with SMA Connector	SparkFun [6]	1
6	URM09 Ultrasonic Sensors	DFRobot Gravity [7]	4	$52.00
7	PCB	JLCPCB [8]	1	$5.00
8	Plexiglass		1
9	APA102 Ring LED	Sparkfun [9]	1	$11.50
10	LEDs for obstacle detection, GPS lock status, and web app lock status		6
11	Rotary Encoder & Wheel Set	[10]	2	$10.99
12	Set of Headlights and taillights	eBay [11]	1	$3.99
13	Logic Level Converters	Sparkfun [12]	1	$3.50
14	Buck Converters		1

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Printed Circuit Board

<Picture and information, including links to your PCB>

We designed and implemented two PCBs: CAN Bus PCB and RC Car PCB.

CAN Bus PCB Schematic

CAN Bus PCB Board

RC Car PCB Schematic

RC Car PCB Board

CAN Communication

<Talk about your message IDs or communication strategy, such as periodic transmission, MIA management etc.>

Our message IDs are arranged with priority given to the nodes in the following order: DRIVER, SENSOR, GEO, MOTOR.

We decided to give 32 message IDs to each node and to separate the nodes' message IDs accordingly.

	Node	Message ID Range
1	DRIVER	32 - 63
2	SENSOR	63 - 95
3	GEO	96 - 127
4	MOTOR	128 - 159

Hardware Design

<Show your CAN bus hardware design>

DBC File

Gitlab link to our master branch's DBC file

Our DBC file includes the SENSOR, DRIVER, MOTOR, and GEO nodes.

Below are the messages defined in the file:

BO_ 32 DRIVER_TO_MOTOR_CMD: 3 DRIVER
 SG_ DRIVER_TO_MOTOR_steer : 0|9@1+ (1,-180) [-180|179] "" MOTOR
 SG_ DRIVER_TO_MOTOR_speed : 9|5@1+ (1,0) [0|31] "RPM" MOTOR
 SG_ DRIVER_TO_MOTOR_current_rpm : 14|10@1+ (1,0) [0|1023] "RPM" MOTOR

BO_ 33 DRIVER_DEBUG_MSG: 1 DRIVER
 SG_ DRIVER_DEBUG_MSG_sensor_mia : 0|1@1+ (1,0) [0|0] "" DBG
 SG_ DRIVER_DEBUG_MSG_geo_mia : 1|1@1+ (1,0) [0|0] "" DBG

BO_ 64 SENSOR_TO_DRIVER_SONARS: 4 SENSOR
 SG_ SENSOR_TO_DRIVER_SONARS_front_left : 0|8@1+ (1,0) [0|0] "" DRIVER
 SG_ SENSOR_TO_DRIVER_SONARS_front_middle : 8|8@1+ (1,0) [0|0] "" DRIVER
 SG_ SENSOR_TO_DRIVER_SONARS_front_right : 16|8@1+ (1,0) [0|0] "" DRIVER
 SG_ SENSOR_TO_DRIVER_SONARS_back : 24|8@1+ (1,0) [0|0] "" DRIVER

BO_ 65 GPS_DESTINATION_LOCATION: 7 SENSOR
 SG_ GPS_DESTINATION_LOCATION_latitude : 0|28@1+ (0.000001,-134.217727) [-134.217727|134.217728] "" GEO,DRIVER
 SG_ GPS_DESTINATION_LOCATION_longitude : 28|28@1+ (0.000001,-134.217727) [-134.217728|134.217728] "" GEO,DRIVER 

BO_ 66 SENSOR_TO_DRIVER_WHEEL_ENCODER_MSG: 2 SENSOR
 SG_ SENSOR_TO_DRIVER_WHEEL_ENCODER_MSG_rpm : 0|10@1+ (1,0) [0|0] "RPM" DRIVER,DBG

BO_ 67 SENSOR_TO_DRIVER_APP_CONNECTION_MSG: 1 SENSOR
 SG_ SENSOR_TO_DRIVER_APP_CONNECTION_MSG_app_connected : 0|1@1+ (1,0) [0|0] "" DRIVER 

BO_ 96 GEO_STATUS: 5 GEO
  SG_ GEO_STATUS_compass_heading : 0|9@1+ (1,0) [0|359] "Degrees" SENSOR,DRIVER
  SG_ GEO_STATUS_destination_heading : 9|9@1+ (1,0) [0|359] "Degrees" SENSOR,DRIVER
  SG_ GEO_STATUS_distance_to_destination : 18|16@1+ (0.1,0) [0|0] "Meters" SENSOR,DRIVER

BO_ 97 GEO_DEBUG_MSG: 1 GEO
  SG_ GEO_DEBUG_MSG_lock_status : 0|1@1+ (1,0) [0|0] "" DRIVER,DBG
  SG_ GEO_DEBUG_MSG_num_satellites : 1|4@1+ (1,0) [0|15] "" DRIVER,DBG

BO_ 98 GEO_CURRENT_LOCATION_DEBUG: 7 GEO
  SG_ GEO_CURRENT_LOCATION_DEBUG_latitude : 0|28@1+ (0.000001,-134.217727) [-134.217727|134.217728] "" DRIVER,DBG
  SG_ GEO_CURRENT_LOCATION_DEBUG_longitude : 28|28@1+ (0.000001,-134.217727) [-134.217728|134.217728] "" DRIVER,DBG

BO_ 99 GEO_CURRENT_DESTINATION_LOCATION_DEBUG: 7 GEO
  SG_ GEO_CURRENT_DESTINATION_LOCATION_DEBUG_latitude : 0|28@1+ (0.000001,-134.217727) [-134.217727|134.217728] "" SENSOR,DBG
  SG_ GEO_CURRENT_DESTINATION_LOCATION_DEBUG_longitude : 28|28@1+ (0.000001,-134.217727) [-134.217728|134.217728] "" SENSOR,DBG

BO_ 128 MOTOR_DEBUG_MSG: 3 MOTOR
 SG_ MOTOR_DEBUG_MSG_echo_steer : 0|3@1+ (1,-2) [-2|2] "" DBG
 SG_ MOTOR_DEBUG_MSG_echo_speed : 3|5@1+ (1,0) [0|31] "RPM" DBG
 SG_ MOTOR_DEBUG_MSG_echo_rpm : 8|10@1+ (1,0) [0|1023] "RPM" DBG

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Sensor ECU

Sensor Node GitLab

Hardware Design

We used 4 Gravity DFRobot URM09 ultrasonic sensors. These ultrasonic sensors are used by the RC car for the purpose of obstacle avoidance. Three sensors were placed on the front side of the RC car and one on the back. They use I2C communication to send distance data to the SJ2 microcontroller. On the SJ2 microcontroller, P0.10 was used for SDA, and P0.11 was used for SCL. The measurement range is 300cm. It takes in 3.3V supply voltage. Using the I2C driver, the registers on the ultrasonic sensors were configured and the distance was read from the specified registers in the datasheet.

Software Design

The ultrasonic sensors use the I2C driver available in the project. The implementation is done in the 10Hz periodic callback function. After writing to the control register address of the ultrasonic sensors, the distance values are read from the appropriate distance. The sensors periodically send sound waves at different times. After the distance values were read, they were sent to the driver for obstacle avoidance.

Technical Challenges

• Ultrasonic sensor interference

Since we had 3 ultrasonic sensors on the front side sending sound waves, there was interference between them. As a result, the values being read from the sensors were incorrect. To resolve this issue, instead of sending sound waves at once from all the front sensors in the periodic callbacks function, we decided to send them at different times.

• Ultrasonic sensor wiring not secure

One of the issues we faced was that the sensors would not be connected properly because the RC car was constantly being moved around. A solution was to clean up the wiring and using a PCB. Also, we would use CAN Busmaster to check which sensors were not connected.

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Motor ECU

Motor Controller GitLab

Hardware Design

The hardware design for the motor controller was determined by the hardware of the car. We knew that the cars motors were controller through an electronic speed controller(ESC) and just had to interface the SJ2 with this. The top of the receiver revealed 12 pins, in 4 rows of 3. Each row had the following according the the sticker: GND, VCC, and signal. The signal pin would be hooked up to the pins which are firmware configured to output PWM.

Software Design

Controlling the motors was done through firmware generating PWM signals. We decided to begin by hooking up the car's receiver to a Saleae Logic Analyzer to see the waveforms generated when using the remote control that came with the car. This was helpful in many ways. First, we were able to see which channel was used for the steering servo, and which was used for the actual motor. Second, we were able to see the maximum, minimum, and neutral PWM duty cycles required and the period period of the waveform. Lastly, we were able to visually see the different sequences necessary to run the motors.

Technical Challenges

< List of problems and their detailed resolutions>

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Geographical Controller

<Picture and link to Gitlab>

Software Design

<List the code modules that are being called periodically.>

Waypoints Algorithm

Technical Challenges

< List of problems and their detailed resolutions>
1. Compass calibration

   * Use magnetic field of current position
   * Use Magneto software

2. Reliable compass readings

   a. Flip the compass upside down for more accurate readings

Resources

1. GPGGA Message Definition [13]
2. LSM303DLHC Datasheet [14]
3. Venus638FLPx GPS Receiver Datasheet [15]

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Communication Bridge Controller & LCD

<Picture and link to Gitlab>

Software Design

<List the code modules that are being called periodically.>

Technical Challenges

< List of problems and their detailed resolutions>

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Master Module

<Picture and link to Gitlab>

Software Design

<List the code modules that are being called periodically.>

Technical Challenges

< List of problems and their detailed resolutions>

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Mobile Application

<Picture and link to Gitlab>

Software Design

<List the code modules that are being called periodically.>

Technical Challenges

< List of problems and their detailed resolutions>

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Conclusion

<Organized summary of the project>

<What did you learn?>

Advise for Future Students

<Bullet points and discussion>

• Add a mobile kill-switch to stop the car
  • The car may drive at high speeds and not behave as expected. It is helpful to be able to wirelessly stop the car.
• Unit test code modules to verify expected behavior
• Once your car can move, test outside on the garage.
  • Ultrasonic sensors give incorrect readings at steep angles, making testing in the hallway somewhat difficult.
  • Compass readings are also more accurate outside the building where there is less interferance.