SSL_DMH7 Chassis Control

This project implements the control system for a 4-wheel omnidirectional robot using DM3519 motors.

Physical Parameters

• Robot Configuration: 4-wheel omnidirectional drive
• Wheel Radius: 26.2mm
• Robot Radius (center to wheel): 86mm
• Gear Ratio: 4:1
• Wheel Angles (measured from positive x-axis):
  • Wheel 1: ?/2 + 1.0 rad
  • Wheel 2: 3?/2 - 0.75 rad
  • Wheel 3: 3?/2 + 0.75 rad
  • Wheel 4: ?/2 - 1.0 rad

Motor Configuration

• Motor Type: DM3519
• Motor IDs:
  • ID1: 0x201
  • ID2: 0x202
  • ID3: 0x203
  • ID4: 0x204
• Current Limits:
  • Maximum Current: 3A
  • Current Deadband: 30mA
  • Current Scale: -16384 to 16384 maps to -3A to 3A
• CAN Protocol:
  • Control Frame ID: 0x200 (all motors)
  • Feedback Frame ID: 0x201-0x204 (individual motors)
  • Update Rate: 1kHz

Control Parameters

Speed Limits

• Maximum Linear Velocity: 2.0 m/s
• Maximum Angular Velocity: 4.0 rad/s
• Maximum Wheel Speed: 60.0 rad/s

PID Control

• Control Loop Rate: 1kHz (1ms)
• Velocity Deadband: 0.2 rad/s
• Output Filtering: 0.2 (low-pass coefficient)
• PID Parameters per Motor:
  • Kp: 50.0
  • Ki: 1.0
  • Kd: 6.0
• Anti-windup Limits: ±5000

Remote Control Mapping

• Channel 1: X Translation (right positive)
• Channel 2: Y Translation (forward positive)
• Channel 4: Rotation (clockwise positive)

Communication Interfaces

FDCAN Configuration

• FDCAN1: Available for expansion
• FDCAN2: Available for expansion
• FDCAN3: Motor control and feedback
  • Baud Rate: Standard CAN
  • Frame Format: Classic CAN
  • Filter: IDs 0x200-0x204

Motor Feedback Format

Each motor sends 8-byte feedback frames:

1. Rotor Angle (2 bytes): 0-8191 maps to 0-360°
2. Rotor Speed (2 bytes): RPM
3. Torque Current (2 bytes): -16384 to 16384
4. Temperature (1 byte): °C
5. Error Status (1 byte)

Safety Features

1. Signal Loss Protection:

   • All motors stop when remote signal is lost
   • Automatic recovery when signal returns

2. Current Limiting:

   • Hardware limit: 3A per motor
   • Software deadband: 30mA
   • Hysteresis in current control

3. Speed Limiting:

   • Linear velocity capped at 2 m/s
   • Angular velocity capped at 4 rad/s
   • Individual wheel speeds normalized if exceeded

Building and Flashing

Use the provided Makefile:

make -j      # Build the project with parallel jobs
make clean   # Clean build files

Dependencies

• STM32H723 MCU
• HAL Library
• DM3519 Motor Protocol