Research On Sliding Mode Control Method And Its Application In Chaotic Synchronization Contro

The synchronization control of chaotic systems is often disturbed by external disturbances or system uncertainties.Therefore,the sliding mode control method is suitable for application in chaotic synchronization control because of its strong robustness.In order to improve the control performance of chaotic synchronization system,the improvement of the sliding mode control method is studied by combining the related theories of integral sliding mode control,terminal sliding mode control and global sliding mode control.Integral sliding mode surface is widely used in sliding mode control because it can eliminate the steady state error and improve the control accuracy.However,the traditional integral sliding mode surface will deteriorate the transient performance and even destroy the stability of the system when the initial error is large.Therefore,the integrand function in the sliding mode surface is improved,a nonlinear integral sliding mode surface that can reduce overshoot and speed up system convergence is designed.The sliding mode control law is designed and the complete synchronization and anti-synchronization control of the chaotic systems with the same structure is realized.In order to achieve the finite time convergence of the error along the sliding mode surface,the power-exponential function integral term of the error is introduced into the terminal sliding mode surface,and an improved integral terminal sliding mode surface is constructed.Aiming at the synchronization control of the chaotic systems with unknown parameters,uncertain items and external disturbances,the adaptive terminal sliding mode control law is designed,and the stability of the synchronization system is proved.The system simulation analysis is also realized.Based on the integral terminal sliding control,a global integral terminal sliding mode controller is constructed to eliminate the approaching stage of sliding mode control and improve the global robustness of the system.A new global sliding mode factor term which can converge to 0 in finite time and remain unchanged is designed,the evolution speed of the dynamic sliding mode surface is accelerated,thus the fast response of the system is improved.The simulation study of the complete synchronization control and projection synchronization control of the chaotic systems with different structures is completed.In order to make the synchronization error of secure communication system based on chaotic synchronization converge rapidly in finite time,an improved global integral terminal sliding mode surface is designed by combining the improved terminal sliding mode surface with the new global sliding mode factor.Based on the state observer theory,the synchronization control study of chaotic secure communication is realized.Simulation results show the effectiveness of the proposed method.