Hello Randy- Thanks for this great forum, from which I have learned a lot. I have been trying, but having a hard time tuning a skid steer rover. I am following the process of tuning speed, turn-rate, and navigation. I am not able to tune the turn rate satisfactorily. Please see my THR value graph and PIDS graph below. (Additionally, it is a bit strange that the gz (Gyro Z-axis) value only shows ~25 degrees/second, under manual mode, which means it takes over 6 seconds to do a complete turn. It seems my vehicle can complete a turn much faster than that.)
The symptom I am having is that if I set ATC_STR_FF to 0.8, which is close to PIDS.Tar, the rover overturns almost 90, or 360 degrees on that particular turn shown on the picture, before reverting back to preset course. My PIDS.Act is very much off from the PIDS.Tar as shown below.
If I set the FF to a much lower value at 0.22, which is much lower than PIDS.Tar, the rover takes multiple small turns to complete a turn with a sharper angle. (I have ATC_STR_RAT_MAX=24, WP_PIVOT_ANGLE=30, and WP_PIVOT_RATE=0.)
Additionally, I have also followed the comments from jimovonz below to calculate ATC_STR_RAT_FF. I got about 0.35 for the skid steer assuming one of the wheels turning and the other fixed. If I assume Ardurover commands two wheel to run at opposite direction, meaning the “wheel separation” referred below will be halved and I will only need 0.18 for the ATC_STR_RAT_FF parameter. I have tried those but no luck so far.
Could you please provide me some guidance? Thank you