一类输入受限非线性系统动态面控制方法研究

Dynamic Surface Control for a Class of Nonlinear Systems with Input Constraints

针对一类输人受限严反馈非线性系统,提出了一种动态面跟踪控制方法。利用双曲正切函数和辅助控制信号对系统非线性模型进行等价变换,解决了饱和函数的非光滑性给控制设计带来的问题。引入一个参数时变的非线性辅助方程,结合方程提出一种能克服输入受限问题的动态面控制方法。利用动态面技术解决了反推控制设计过程中存在的"微分爆炸"问题。通过Lyapunov稳定性理论证明闭环系统的所有状态一致最终有界且跟踪误差能收敛到任意小。通过超低空空投下滑阶段算例验证了方法的有效性。

An dynamic surface tracking control method is proposed for a class of strict-feedback systems with input constraints.A model with input constraints characteristic is developed using a hyperbolic tangent function,which overcomes the difficulty from the non-smooth nonlinearity of saturation function in control design.A nonlinear auxiliary equation with parameters being time-varying is introduced,and a corresponding dynamic surface control method is then designed based on this model to solve the problem of input constraints.The＇explosion of complex＇problem existing in backstepping method is avoided using the dynamic surface technique.Based on Lyapunov stability theory,we prove that all the signals of the closed-loop system are uniformly ultimately bounded,and the tracking error can converge to a small neighborhood of the origin.Simulation results of ultra-low-altitude airdrop process are presented to demonstrate the effectiveness of this method.