Adaptive Control On The Hysteresis Nonlinear Systems With Bouc-Wen Model

With the growing development of science and technology,micropositioning system has been an important part of modern advanced manufacturing technology,and its positioning accuracy has become a key factor in related fields.In the ultra precision positioning systems,the smart materials(piezoelectric,shape memory alloy,magnetostrictive materials)have high qualities which are fibre-optical communication,microelectronics manufacture.However,hysteresis existing in the smart materials would destroy the system performance.As a kind of nonlinear phenomenon,hysteresis is also a multi-valued mapping memory.It may cause static error,vibration,even worse cause the instability of the systems.It's meaningful to model the hysteresis,and design effective controller to eliminate the adverse effects caused by the hysteresis,such that the precise control could be realized.The dissertations are organized as follow:(1)Control design for uncertain hysteresis nonlinear systems with Bouc-Wen modelA prescribed performance adaptive control is proposed for the uncertain nonlinear systems with the hysteresis.First,the hysteresis phenomenon is described by the Bouc-Wen model,and the upper bound is derived.Second,the tracking error is confined to residual set by using the prescribed performance concept.The adaptive technique is used to approximate the uncertainty.And the backstepping controller could eliminate oscillation and overshoot of systems.The proposed controller can track the desired output closely and guarantee the prescribed performance.(2)Controller design for output-constrained Bouc-Wen nonlinear systems with uncertaintyFor a class of output-constrained uncertainty nonlinear systems with hysteresis,a Barrier Lyapunov Function(BLF)is constructed by the constraint interval to achieve the output-constrained conditions.The adaptive technique is used to approximate the uncertainty of the system and the backstepping controller eliminates the influence ofthe hysteresis,constraint and uncertain constants simultaneously,so the output-constraint hysteresis system is effectively controlled.(3)Controller design for Bouc-Wen nonlinear systems with unknown control directionAn adaptive backstepping control method is proposed for a class of hysteresis nonlinear systems with unknown control direction and uncertainty.Nussbaum function is used to overcome the unknown control direction,and the error transformation is used to confine the systems error into a predefined residual.An adaptive approach is employed to reduce oscillation and overshoot.All the signals in the closed-loop system are uniformly bounded and the controller ensures the transient and steady performance.