Hail-Bopp has two CAN buses. One is the CAN bus that came with our stock vehicle, and the other we added to support the EPAS and other peripherals.
We call the former the GEM Bus, as it is the default bus that came with the Polaris GEM e6.
We call the latter the Robot Bus, as it supports our autonomous functionality.
Bitrate is 250,000 bits per second.
⚠ If a device (e.g. a CANable) connects to the GEM Bus at a rate other than 250kBps, the vehicle will shut down.
Bitrate is 500,000 bits per second.
Our Electronic Power Assisted Steering (EPAS) system is managed by an EPAS18 Ultra controller. The Ultra acts as an intermediary between other CAN devices and the actual steering motor.
The Ultra uses a 500kBps CAN connection with non-extended (11-bit) message IDs. To send a command to the EPAS using python-can, you must explicitly specify a non-extended ID.
Example:
message = can.Message(arbitration_id=0x296, data=data, is_extended_id=False)| Byte | Description |
|---|---|
| D0 | Torque (bits) |
| D1 | Motor duty (%) |
| D2 | Current (A) |
| D3 | Supply voltage (1 bit = 100mV) |
| D4 | Switch position (0 to 15) |
| D5 | Box temp (celcius) |
| D6 | Torque A (raw value in bits) |
| D7 | Torque B (raw value in bits) |
| Byte | Description |
|---|---|
| D0 | Steering angle (bits) |
| D1 | Analog Channel 1 (bits) |
| D2 | Analog Channel 2 (bits) |
| D3 | Selected map (0-5) |
| D4 | Error messages |
| D5 | Bit field of digital I/O values |
| D6 | Bit field of status flags |
| D7 | Bit field of limit flags |
Used to send out commands.
| Byte | Description |
|---|---|
| D0 | Steering map (0 = local mode, 1-5 = steering map) |
| D1 | Torque A |
| D2 | Torque B |
| D3 | Not used |
| D4 | Not used |
| D5 | Not used |
| D6 | Not used |
| D7 | Not used |
Turn slowly to the right with: MAP between 1-5 (higher is faster), torque A = 143, torque B = 112.
Message: 01 8F 70 00 00 00 00 00
$Torque_A + Torque_B = 255$