基于非线性干扰观测器的无人平台有限时间镇定控制

Finite Time Stabilization of Unmanned Platform Based on Nonlinear Disturbance Observer

研究了存在模型不确定性和外界干扰工况下的非完全对称无人平台有限时间镇定控制问题.考虑模型参数矩阵的非对角线元素存在非零项,仅通过一次微分同胚变换即将原模型化为级联系统形式,简化了计算步骤;基于此级联系统借助终端滑模和反步控制方法设计了有限时间收敛控制器,解决了传统反步滑模控制器收敛速度缓慢的问题;通过引入1阶低通滤波器,对镇定控制器结构进行了优化,避免了执行器陷入"饱和";基于非线性干扰观测器对外界干扰及系统不确定性进行平滑估计和补偿,无需明确知道估计误差的上界即有效提高了控制器的鲁棒性.最后基于Lyapunov理论证明了闭环系统具有均方意义稳定性并进行了数值仿真,仿真结果验证了控制器的有效性和鲁棒性.

The finite time stabilization was discussed for an incomplete symmetry unmanned platform under a model perturbation and environmental disturbance condition.Due to the nondiagonal inertia and damping matrices existing in the original model,the investigated model was converted into two cascade subsystems with the global diffeomorphism transformation just for once to simplify the process of calculations.For these subsystems,a finite time convergence controller was developed based on a terminal sliding mode and back-stepping technique to improve the robustness and convergence speed.Introducing a first order low-pass filter,the composedness controller was optimized to prevent the saturation of the actuator.A new nonlinear disturbance observer was designed to estimate and compensate the perturbations and disturbances for the improvement of the controller＇s robustness without the definite boundaries of the estimation errors.Finally,the system was proved to be mean-square stable based on the Lyapunov theorem.The simulation results validate the effectiveness and robustness of the proposed controller.