基于改进L_1自适应的姿态控制研究

An Improved L_1 Adaptive Control for Attitude Regulation

针对含匹配不确定性和时变干扰的多变量耦合系统,提出改进L1自适应控制,并进行控制系统闭环分析.针对常规解耦中积分型闭环系统的临界稳定问题,在常规解耦之后附加反馈控制,从而构成同时保证系统解耦性和稳定性的线性解耦控制.解耦后,系统表示为由若干含匹配不确定性和时变输入干扰的无耦合子系统组成.针对各子系统中不确定性和干扰问题,采用L1自适应控制以保证系统的鲁棒性.此外,为避免控制量的瞬时大幅值和大变化率,设计参考信号变换方式,即参考信号中的阶跃跳变部分用正弦信号替代.最后,将所设计改进L1自适应控制应用于飞行器姿态调节中,并通过Matlab数值仿真对所设计的姿态控制系统进行测试和验证,结果表明所设计控制算法和姿态控制系统可行有效.

A class of multivariable linear system with coupling effect,matched uncertainty and time-varying interference was investigated,for which a new improved L1 adaptive control was proposed.Firstly,the linear decoupling control was developed for problem of coupling effect.Compared to traditional decoupling control whose closed-loop system was in a critical stable state,the proposed decoupling control guarantees both decoupling and stability.Secondly,after decoupling control,the controlled system can be divided into several decoupled subsystems with matched uncertainty and time-varying disturbances.L1 adaptive control was then utilized to cope with the uncertainty and interference,which actually ensures robustness of closed-loop system.Moreover,step signal or square-wave signal will be replaced with a differentiable signal to avoid the extremely large transient amplitude or oscillation of control input.Finally,the attitude control problem was addressed with the proposed control law,and simulation results indicate that the improved L1 adaptive control is effective and efficient.