TDPS Smart Vehicle Project - Navigation Module

for the course UESTC3010: Team Design and Project Skills (TDPS)

Team 13

IMPORTANT NOTICE: THIS IS A COURSE PROJECT. ANY USES OF THE CODE THAT MIGHT CONSTITUDE PLAGIARISM FOR EITHER THIS COURSE OR ANY OTHER COURSES ARE NOT ALLOWED.

Team Members

Name	Group	Responsibility
ZHANG Keyu	Hardware	Team Leader / Hardware Group Manager
LIANG Sidi	Vision	Project Manager / Vision Group Manager
DIAN Mingqian	Control	Control Group Manager
ZHANG Yuxin	Hardware
HUANG Yukun	Hardware
LIU Yicong	Hardware
LI Chenjun	Control
LIU Yi	Control
YU Yunke	Vision
SUN Qihao	Vision

The modules contained in this repository are built by Liang Sidi and Yu Yunke.

Important Files:

• main.py
• messaging.py
• HCSR04
  • __init__.py
• Navigation
  • __init__.py
  • odometer.py

Communication protocol：

The specified parameters for UART communication to the main control board are as follows:

• Baudrate: 115200
• Bits: 8
• Parity: None
• Stop: 1

Frame Structure

The communication protocol involves the exchange of frames, each consisting of specific byte sequences. The frames convey different messages based on their content. The meanings of key byte sequences are explained below:

1. 0xCC: Acknowledgment (ACK)
2. 0xDD: Retransmission Request

Message Content Format

The actual message content is structured as follows:

1. Start Marker: 0xAA, 0x55
2. Message Length
3. Message Content (in JSON format)

Communication Sequence

Navigation Module to Master

1. Send: 0xCD
2. Receive: 0xAA, 0x55, {length of message n}, {message n}, 0xCC (if correct) or 0xDD (if incorrect)
3. Send: 0xCC (if correct) or 0xDD (if incorrect)
4. Receive: 0xAA, 0x55, {length of message m}, {message m}, 0xCC (if correct) or 0xDD (if incorrect)
5. Send: 0xCC (if correct) or 0xDD (if incorrect)
6. Repeat the sequence...

Sender	Receiver	Message Type	Byte Sequence	Note
Nav	Master	Control	0xCD	Initiates the communication
Master	Nav	Data	0xAA, 0x55, {length of message n}, {message n}	-
Nav	Master	Acknowledgment	0xCC (0xDD if incorrect)	-
Master	Nav	Data	0xAA, 0x55, {length of message m}, {message m}	-
Nav	Master	Acknowledgment	0xCC (0xDD if incorrect)	-
Master	Nav	Control	0xCD	Initiates another round of communication
Nav	Master	Data	0xAA, 0x55, {length of message n+1}, {message n+1}	-
...	...	...	...	...

Message Content (4 ~ n)

The message content, ranging from the 4th byte onward, is expected to be in JSON format. Below are examples of the expected JSON structures for the OpenMV line-following section:

OpenMV Line Following (Sent by Navigation Module)

{
  "Info_Task": 0,
  "Info_Patio": 1,
  "Info_Stage": 2,
  "Control_Angle": 45,
  "Control_Velocity": 10,
  "Control_PID": 3,
  "Control_Cam_Pitch": 1,
  "Control_Ball": 0,
  "Control_Comm": 1
}

Main Controller (Sent by Master)

{
  "Info_Encoder_A": 123.45,
  "Info_Encoder_B": 67.89,
  "Info_Encoder_C": 101.23,
  "Info_Encoder_D": 54.32,
  "Info_Cam_Pitch": 1,
  "Info_Ball": 0,
  "Info_Comm": 1
}