Ackermann Steering plugin's steering only mode shows opposite behaviour than expected

[sauk2]

Environment

• OS Version: Ubuntu 22.04
• Source build of gz-sim8

Description

Issue pertains to Ackermann Steering plugin's steering_only mode specifically these lines.

• Expected behavior: The inner wheel should turn more than the outer wheel during turning
• Actual behavior: The opposite takes place. (Here I have commented out the chassis visual in the SDF for better visibility)

Steps to reproduce

1. Add the following tag in the example SDF file of Ackermann Steering plugin.

  <steering_only>True</steering_only>

2. Build and source the workspace
3. Launch using the following command

  gz sim ackermann_steering.sdf

4. Publish the following

  gz topic -t "/model/vehicle_blue/steer_angle" -m gz.msgs.Double -p "data: 0.4"

Additionally comment out chassis visual for better visibility

Solution

Changing signs in these equations should suffice.

P.S. Raising a PR regarding the same