Real-Time CMAC Neural Network Control of a Piezo-Electric Actuated Toolpost With Disturbance Decoupled Observer

Abstract

Abstract The design and fabrication of a cerebellar model articulation controller (CMAC) controlled piezo-electric actuated fast tool servo has been reported [Pinsopon et al]. A capacitance type gap sensor with less than 1 nm resolution was used for position feedback. Cerebellar model articulation controller (CMAC) neural network control algorithm has been implemented parallel to the PID controller as the control scheme, and its performance was compared with the standard PID control. The CMAC control algorithm improves the tracking accuracy compared to the PID algorithm. However, the CMAC control system had a poor disturbance rejection capability as compared to the PID control system. In this research, state feedback with disturbance observer is implemented as the control scheme replacing PID controller to improve the disturbance rejection capability. CMAC control algorithm is also used in the feedforward loop to improve the tracking capability of the closed loop system.