Patent ID: 7141946

Claim:
An apparatus for use with a motor controller that receives a command velocity and that applies voltages to drive a motor at the command velocity, the apparatus comprising: a dual inertia lost motion assembly including a motor and a load couplable to the motor, the lost motion assembly characterized by at least some lost motion between the motor and the load, the motor and load together characterized by a total assembly inertia; an acceleration error determiner for generating an acceleration error that is the difference between a derivative of the command velocity and a motor acceleration value; and a low pass acceleration error filter filtering the acceleration error and having a gain set as a percentage of the total assembly inertia, the acceleration error filter providing the filtered signal to the controller, the controller using the filtered signal to adjust the applied voltages; wherein the controller includes a velocity error filter having a velocity error time constant and wherein the acceleration error filter has an acceleration error time constant that is between two and four times the velocity error time constant.