I have modified the seatedhuman demo, adding a steering wheel to simulate steering and it worked well. Referring to the pedal demo, I added a pedal located in the desired position and changed the pelvis joint. When setting initial conditions, no system error occurred, but the pedal was located strangely on the back of the head so the right leg was in a strange position as well.
I wonder what caused this problem?
Many thanks for your help. It seems that I have misunderstood the reference frame of the hinge.
I will keep working on it and try more efforts to improve it.