need clearity on joint controller state message [closed]
Update: I've also noticed that under some pid setting a set point of zero still results in an error value for a continuous joint on a wheel. This should not be the case as it should already be at a neutral gravity state on flat ground.
Update: As I play with this more I see that this error value can be over or under the stated set point this seems to be a pid related issue. However I do not understand why being that both left and right motors have the same pid setting why the difference between the left and right error values.
I am having a problem or miss understanding of the Joint Controller State. I send the controller two velocities for a right and left wheel each +.05 meters per sec. The Joint Controller State message show the following. I am treating the values as velocities in meters per sec.
process_value -> pv
er -> error
sp -> set_point
[ INFO] [1380852360.412367809, 4.000000000]: pv1=[-0.023923] pv2=[0.013752]
[ INFO] [1380852360.412429679, 4.000000000]: er1=[0.073923] er2=[0.036248]
[ INFO] [1380852360.412461154, 4.000000000]: sp1=[0.050000] sp2=[0.050000]
First why are the errors different, the wheels are exactly the same and running on a flat surface in gazebo.
Second why is the error on joint-1 greater then the velocity sent and why did the actual process value go negative.
I thought the error is that part of the set point (original velocity) that was not executed. so pv1 should be 0 I would guess.
