具有输入约束的飞机姿态L_1自适应控制

L_1 Adaptive Controller for Aircraft Attitude with Input Constraints

针对具有模型不确定性、控制舵面故障以及非线性干扰的飞机俯仰姿态控制问题,基于L1自适应方法设计增广控制器。设计合适带宽的低通滤波器,以满足控制器快速自适应要求,保证系统输入输出信号的一致性能有界。考虑伺服控制实际存在的幅值约束,推导出所设计的自适应控制系统的稳定性条件及其性能界,即忽略幅值约束时,选择足够大的自适应增益,闭环系统性能能够任意接近参考系统;考虑幅值约束时,闭环系统的性能可以通过增大自适应增益得以改善,但是不能任意接近参考系统。仿真验证了所设计的飞机姿态控制系统的有效性,结果表明控制器对有界不确定性和干扰具有鲁棒性,同时满足输入约束要求。

For the aircraft pitch attitude control with model uncertainties, control surface failure, and nonlinearity disturbance, an augmentation controller based on L1 adaptive is developed. The low-pass filter with an appropriate bandwidth is designed to meet the requirements of fast adaptation and ensuring uniformly bounded performance for both the system input and output signals. Considering the fact that the servo control system with amplitude constraints, this paper derives stability condition as well as per- formance bounds of the controller. The results show that, choosing sufficiently＇ large adaptation rate in the absence of amplitude constraints, the performance of the closed loop system can be made arbitrarily close to the L1 reference system. And the performance can be improved by increasing the adaptation rate in the presence of amplitude constraints, but cannot be arbitrarily close to the reference system due to the control deficiency. The proposed design is applied to pitch attitude control system for an aircraft. The simulation results verify robustness to bounded uncertainty and disturbances, while avoiding input saturation.