The steering firmware is responsible for reading values from the torque sensor, sending reports on its state, and receiving steering commands and fault reports from the control CAN. When the steering firmware receives a steering command message, it will then output the commanded high and low spoof signals onto its connection to the EPAS ECU, sending it torque requests. Receiving a fault report will cause the steering module to disable.

There are three possible fault states:

• Sensor disconnect
  • The firmware will periodically check the sensors to ensure none of them read a value of zero (an indication that they have become disconnected).
  • If a sensor is detected to be disconnected, control will be disabled and a fault report will be published
• Command timeout
  • The firmware will monitor the time between receiving commands and ensure there is a steady connection to a higher level application
  • If it is determined that commands are no longer being received, control will be disabled and a fault report will be published
• Operator override
  • The firmware will monitor for a manual actuation of the steering wheel by a human operator in the event of an emergency override of OSCC control
  • If an operator override is detected, control will be disabled and a fault report will be published

All modules listen for the fault report message and disable themselves if learning of a fault in a different module.

• Receives steering commands from the API
• Receives fault reports from other modules
• Sends steering reports with current state information
• Sends fault reports on fault event

Note: Steering reports should be checked after sending steering enable command to ensure that the module received the command and enabled properly.

Note: Steering reports should be checked after sending steering disable command to ensure that the module received the command and disabled properly.

Note: Limit the rate at which you send commands onto the CAN bus to prevent overloading the bus and the processors on the modules. A rate of around 20Hz should be sufficient.

Follow the README build instructions, then run:

make steering

To upload to the Arduino:

make steering-upload