Coordinated motion control subjected to actuator saturation

This dissertation considers a coordinated motion control problem in the presence of actuator saturation. This problem is motivated by multi-axis contouring systems such as machining centers and robot manipulators.;For a class of single input linear systems, an anti-windup controller design methodology is proposed for the asymptotic tracking of a certain kind of reference input. The proposed controller is an internal model based controller with an anti-windup term. It is shown by Lyapunov methods that such a controller not only guarantees the asymptotic tracking of a certain specific reference input, but also reduces the performance degradation compared to the case where no anti-windup term is included in the controller. This design methodology is then extended to the case where plant uncertainty is also considered.;One fundamental problem in motion control is that the motion of multiple axes or motors must be coordinated. If the feedback controller for each axis is designed and implemented independently, performance degradation or loss of coordination is inevitable during the saturation period regardless of the presence of an anti-windup term in the controller. In this dissertation, two on-line trajectory planning algorithms with one-step preview are proposed to maintain the coordinated motion during the saturation period. By utilizing the robust anti-windup controller design for the feedback controller and the proposed on-line trajectory planning algorithm, the stability of the closed-loop system is guaranteed in the presence of actuator saturation. At the same time, motion coordination is maintained.;An extensive computer simulation study is performed to evaluate the effectiveness of the design presented in this dissertation. As motivated by high-speed/high accuracy machining, simulations are performed using the model of a Matsuura MC510-V-SS vertical machining center.