A wavelet-based multi-resolution PID controller

This paper presents a novel controller based on multi-resolution decomposition using wavelets. The controller is similar to a Proportional-Integral-Derivative controller in principle and application. The output from a motion control system represents the cumulative effect of uncertainties such as measurement noise, frictional variation and external torque disturbances, which manifest at different scales. The wavelet is used to decompose the error signal into signals at different scales. These signals are then used to compensate for the uncertainties in the plant. Through hardware results on a motion control system this controller is shown to perform better than a PID in terms of its ability to provide smooth control signal, better disturbance and noise rejection.