Multi-rate And Nonlinear Control Of The Dual-stage Actuator System

As a novel mechatronic system, the dual-stage actuator (DSA) control system has drawn agreat deal of interest from researchers, and it has led to a wide range of applications in many fields.The DSA system consists of the first and the second actuator in series, which can achieve a betterperformance by delicately control the two actuators, which work on very different scales. Therefore,the DSA system shows its unique advancement and superiority in industrial applications.There are various control algorithms for DSA systems, such as PID control, predictive control,robust control etc. Each algorithm has its own pros and cons. Two new control algorithms areproposed in this thesis, of which the effectiveness is demonstrated by simulation. The outline of thisthesis is as follows:Chapter1briefly describes the background knowledge and the state of art research of DSAsystem;Chapter2summarizes the background knowledge of linear control system and digital signalprocessing, which will be used in following chapters.In chapter3, the physical model of DSA system is introduced, with focus on the compensationof the friction and disturbance for the first actuator.Chapter4presents a composite nonlinear control algorithm. First, we design PTOS to yield asmall overshoot for the primary actuator system, and composite nonlinear algorithm is designed forthe secondary actuator to reduce the overshoot, then, detailed parameter design is carried out toenhance the system performance, finally, a simulink platform is developed in this chapter.Experimental results sufficiently demonstrate the effectiveness of the mentioned algorithm.In chapter5, A multi-rate controller with friction compensation is designed to reduce thecomputational load, which will greatly improve the system’s performance. The multi-rate controllaw can decrease the computational load with a slower update rate about the primary actuator，butthe performance of the whole system is not descending. And then the simulink platform is appliedto test the influence of the ratio m and friction compensation on whole system performance.Finally, the thesis is summarized in chapter6. Some open problems are stated for futureresearch.