/Navigation-Module-for-TDPS

The navigation module for the smart vehicle project. The hardware used for this code is OpenMV H7 plus.

Primary LanguagePython

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
}