wheel torque control produces stuttering movement


i am trying to use the blender game engine to make a virtual environment for a two-wheeled robot. the robot can be controlled by adjusting the torque to each of the wheels. i have been looking around the interwebs, but couldnt find any similar scenarios. in case i overlooked something, it would be great if you could point me there. currently the key allocation for controlling the robot is as follows:

‘q’ applies positive torque to the left wheel

‘a’ applies negative torque to the left wheel

‘w’ applies positive torque to the right wheel

‘s’ applies negative torque to the right wheel

i am trying not to use actuators (please correct me, in case i am mixing up terminology) because i am quite familiar with python and want to put as much as possible into the script. i am also deliberately trying to control the robot by rotation of the wheels instead of translational force applied to the whole vehicle, because i intend to make it physically as accurate as possible.

initially the vehicle moves quite as expected, but playing around for a while it gets stuck as if there were obstacles. but there are none. and i dont think its the edges of the cylindical wheels.

the blender file is attached to this post. it would be great if someone could have a look and help me out with my first approach to the bge.

thanks in advance!


robot.blend (359 KB)

Motion actuator control has bug, try Lining it up on z for rotation axis, only an issue with 6dof I think

thanks for the answer! i am not using 6dof, however, but the hinge joint. i figured that would be best for modelling axes. maybe i was wrong, because this guy http://www.davidwhodo.com/2011/08/accurate-vehicle-simulation-in-blendermorse/ got a lot better results using rigid bodies (i am using dynamic ones) and 6dof instead of hinge joints. ill give it a try later on and post the results.

ok, i got it. i had to remove the collision bounds of the wheels. seems a little odd to me, as collision with the floor is necessary. but anyhow: works.