Control For Actuator Hysteresis Contrained Systems Based On New Quantizers

Control theory is dealing with more complex plants,and the plants are with stronger nonlinearity and uncertainty.On the other hand,to persue higher precision,piezoelectric actuators and magnetostrictive actuators with hysteresis nonlinearities are introduced into industrial production systems and detection equipments.Meanwhile,networked control systems has been widely exploited due to their characteristics of modularity,decentralization and information management centralization.However,when the networked control is introduced to the highprecision systems with hysteresis actuators,a series of problems will be encountered.First,the quantization mechanism introduced by networked control system to reduce communication burden bring in quantization errors.Second,the existence of actuator hysteresis makes it impossible for the state observer to obtain the signals that act on the plant to estimate the states of the system.Worse,under the action of of high-frequence components induced by quantization,the hysteresis cannot maintain its shape and deforms,which leads to unpredictable changes of signal that act on the plant and finally degrades the system performance and causes instability.Therefore,this work focus on issue of quantized control of uncertain nonlinear systems with hysteretic actuactors under state feedback and output feedback condition.This work consists of two part,namely,the state feedback control scheme and the output feedback control scheme.1)The state feedback control scheme for uncertain nonliear systems with hysteretic actuactor is developed.A new filter-connected quantizer is proposed to resolve the confict between quantization and hysteresis by eliminating the high-frequency components in the transmitted signal and constraining the communication rate at the same time.Based on the backstepping technique and the online approximation capability of fuzzy logic systems,a new control strategy is provided for control design,and a new adaptive strategy is given for the adaptive high-cut filter in the filter-connected quantizer.2)Investigate the output feedback control scheme for uncertain nonlinear systems with actuator hysteresis and input quantization.Under the condition of output feedback,the veiling of unknown hysteresis that obstruct the state estimation is another challenging issue,in addition to the conflict between quantization and hysteresis.To resolve these problems,a feedback based quantizer with feedback mechanism and new adaptive strategy is proposed.The feedback based quantizer solves the veiling and conflict,but the systems are still strongly couple with hysteresis and become more complex with the feedback based quantizer.Thus,a new ouput feedback control scheme involving a new output feedback control design strategy is designed.It is strictly proved that under the action of the new quantizers and control schemes,the tracking errors converge to an adjustable neibourhood of zero and all the signals in the closedloop systems are semi-globally uniformly altimately bounded.By a series of simulation experiments and comparision experiements,the effectiveness and advantage of the proposed schemes are verified and illustrated.