Gain tuning

• Check your kp and kv gains.
• Most likely, your kv gain is too low. Keep increasing till the controller stabilizes.

Numerical Instabilities

• Near singularities, operational space control can become ill conditioned (the task-space mass matrix loses rank).
• The standard task controller detects this using an svd and constrains control to an orthogonal null space.
• You may re-implement the standard operational point controller if you want and make the svd defaults more/less sensitive.
• If you analyze the svd thresholds for some robot, please do email Samir about your results.

Robot disappears

• Most likely the robot was getting massive input actuation forces
• It accelerates to inf, and the simulator can't render it anyway
• Remember, rotation does not wrap around in scl. Ie. 2pi != 0