EXPERIMENTAL COMPARISON OF TWO INPUT SHAPING METHODS FOR THE CONTROL OF RESONANT SYSTEMS

摘要

The paper compares two input shaping methods designed to prevent the excitation of oscilla-tory modes in resonant systems. The first method produces a control signal that is the linear combination of delayed versions of the reference input. The resulting control system is linear time-invariant but infinite-dimensional. Its transfer function has an infinite number of complex zeros, and some of them are being placed exactly at the locations of the resonant modes of the plant. In contrast, the second method is based on a pole/zero cancellation of the resonant modes using a finite-dimensional controller. Experi-mental results are presented for a system in which a DC motor is used to control the position of a flexible arm. The step response of the plant is poorly damped, but the transient response is much improved when either input shaping method is used. It is shown that a simple method can be incorporated in the second method for the automatic adjustment of the controller parameters, making it particularly attractive.