Vibration reduction in computer controlled machines

In the approach to vibration reduction presented, a robust control scheme which reduces the effects of friction and the effects of inaccuracies in its modeling is used. The method consists of the design of two loops: an inner loop that controls the position of the motor and an outer loop than controls the position of the endpoint of the carriage. A high-gain inner loop incorporates a coupling term, and is designed to make the response of the motor position much faster than the endpoint position. An input command shaping scheme is used for the outer loop to reduce the vibrations. The complete scheme was applied to a coordinate measuring machine and gave satisfactory results. The controllers designed were simple and provided fast and accurate motion of the endpoint.<>