摘要
针对传统滑模趋近律中的抖振现象、收敛速度慢等不足,提出一种新型变指数幂次趋近律。该趋近律通过使用变指数幂次项,实现了在系统趋近过程中根据不同阶段进行自适应调节的功能,大幅提高了系统的收敛速度,并具有全局有限时间收敛特性。当系统存在模型不确定型和外部有界扰动时,滑模变量可在有限时间内收敛到边界层宽度为1左右的稳态误差界内,且该稳态误差小于现有的双幂次趋近律、快速幂次趋近律和多幂次趋近律等方法的结果。仿真算例验证了所提出趋近律的有效性和优越性。
A variable power reaching law for sliding mode control is proposed aiming at reducing the chattering phenomenon in traditional sliding mode control methods and speeding up the convergence speed.The proposed reaching law adjusts the convergence process adaptively by using a variable power term, so that the system has an obviously faster convergence and has no chattering phenomenon, and it also has the characteristic of global finite-time convergence. It is proved that, for a class of bounded external disturbance,the sliding mode variable converges to a preset steady-state error with the boundary layer width of about 1 within finite time, and the value of the steady-state error is less than the existed reaching laws such as double power reaching law, the fast power reaching law, and so on. Simulation results are given, which demonstrate the validity and superiority of the proposed method.
引文
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