Open CAN Protocol for AGV Chassis Integration

Due to increasing user demand for customized AGV Chassis integration, we decide to open the CAN protocol utilized by Pursuit autopilot. The CAN interface provides a reliable communication between the autopilot and the AGV Chassis, and it also permits further extension to other peripherals.

Protocol Configuration

The Pursuit autopilot supports the CAN 2.0B (extended format) protocol, which can be referred in https://www.ti.com/lit/an/sloa101b/sloa101b.pdf.

../_images/extended_can.png

The configuration for our CAN protocol is:

  • Baud rate: 500K

  • Time Segment 1 (TSEQ1): 8

  • Time Segment 2 (TSEQ2): 3

  • Synchronization Jump Width (SJW): 2

Hint

Note that we utilize the FLU frame for velocities and steering angles in the protocol, namely X (Front), Y (Left), Z (Up), and the steering angle is positive when turning left.

Messages for Ackermann Chassis

  1. Steering Control Command

    ../_images/acker_steering_ctrl_msg.png

  2. Control Feedback Command

The message shall be used together with the Steering Control Command, and it’s sent from the chassis to the autopilot.

../_images/acker_steering_ctrl_fb_msg.png

Messages for 4WS-4WD Chassis

The 4WS-4WD (Four-Wheel Steering and Four-Wheel Drive) chassis is featured with its advanced maneuverability in confined space.

  1. 4WS-4WD Control Command

    ../_images/4W4D_ctrl_cmd_msg.png

  2. 4W4D Control Feedback Command

The message shall be used together with the 4WS-4WD Control Command, and it’s sent from the chassis to the autopilot.

../_images/4W4D_ctrl_fb_msg.png