Steering torque units for Subaru DBC signals

[martinl]

Find ratios for following signals (Nm units):

• Driver steering torque: ["Steering_Torque"]['Steer_Torque_Sensor']
• EPS steering torque: ["Steering_Torque"]['Steer_Torque_Output']

[martinl]

analyzing SSM4 logs vs screen recording may provide some hints

[jnewb1]

SSM4, in NM. Field is called "Torque Sensor Main" In cabana:

[jnewb1]

[martinl]

Nice, can you get some numeric values so we can figure out the conversion formula for dbc

[jnewb1]

Nice, can you get some numeric values so we can figure out the conversion formula for dbc

Yea I’ll try and get a combined dataset with the can data and the ssm4 logs synced up

[jnewb1]

test1.csv

Here's a csv where i synced up the ssm4 data and the can data to the best of my ability. I'm not 100% sure if "Torque Sensor" in ssm4 is torque output or driver input, but it seemed to align better with our current "Torque Sensor" values in the dbc, which would give -0.012 as the factor.

[martinl]

Thanks, I'll create opendbc and openpilot PR-s if you have not done it already

[martinl]

Looks like EPS Steer_Torque_Output already has -10 scaling factor:

  SG_ COUNTER : 8|4@1+ (1,0) [0|15] "" XXX
  SG_ Steer_Torque_Output : 13|11@1- (-10,0) [0|255] "" XXX
  SG_ Signal1 : 24|8@1+ (1,0) [0|511] "" XXX
- SG_ Steer_Torque_Sensor : 45|11@1- (-1,0) [0|255] "" XXX
+ SG_ Steer_Torque_Sensor : 45|11@1- (-0.012,0) [0|255] "Nm" XXX
  SG_ Steering_Active : 61|1@0+ (1,0) [0|1] "" XXX
  SG_ Steering_Disabled : 63|1@1+ (1,0) [0|1] "" XXX

[martinl]

https://github.com/commaai/opendbc/pull/901