Hysteresis Sliding Mode Variable Structure Control Algorithm

System with hysteresis is under the action of reciprocating power to show non-linear nature of the changes. The existence of hysteresis will greatly affect the control performance, not only will exhibit undesirable inaccuracies or oscillations and potentially makes the system unstable.Variable structure control is a special class of nonlinear control, whose control structure is not fixed but can be changed in a dynamic process. So it not only shows a rapid response to the parameters'change and disturbance insensitive, but also has the advantage of an easy physical realization, Hence the design method based on the essence of sliding is proposed. Based on the previous research work, further research on sliding-mode control algorithm of system with hysteresis is carried out in this degree thesis. The main work of the thesis is illustrated as follows:(1)The adoption guidance of hysteresis model, design methods of controllers, architecture strategies of sliding-mode control of systems with hysteresis are surveyed separately, and the existing problems as well as research directions are indicated systematically.(2) A globe sliding mode control associated with compensating based on hysteresis observer is proposed. Prandtl-Ishlinskii (PI) model is used to model the hysteresis nonlinearity, so the system can be divided into two parts. As the precision parameters of the system's uncertain part can't be obtained, the control with hysteresis observer is designed to compensate this nonlinearity.The global stability of the system and tracking a desired trajectory to a certain precision are achieved. Simulation results attained are presented to illustrate and further validate the effectiveness of the proposed control.(3) Deal with globe adaptive Sliding Mode Control of uncertain Systems with Prandtl-Ishlinskii Hysteresis and Disturbances. By using a Prandtl-Ishlinskii model with play and stop operators and by exploring the properties of this model intuitively and mathematically,As the parameters of the system are changed during a period, the positioning accuracy of the system is limited due to the hysteretic nonlinearity. To compensate this nonlinearity, a globe adaptive sliding mode control associated with compensating is proposed .The global stability of the system and tracking a desired trajectory to a certain precision are achieved. Simulation results attained are presented to illustrate and further validate the effectiveness of the proposed control.(4)The novel design method of globe fuzzy sliding-mode control is proposed for a kind of friction unknown hystersis systeam. To mitigate the effects of hysteresis without constructing inverse hysteresis nonlinearity, Lugre mode is applied to combine with fuzzy sliding-mode control, the fuzzy rulers are given to observe hysteresis nonlinearities based on the conditions of sliding-mode control reach law. The global stability of system is proved. Simulation result shows it can track a desired trajectory in high precision.