水下运载器纵向轨迹自适应跟踪控制

Adaptive tracking control of longitudinal trajectory for underwater vehicle

针对强非线性、大俯仰角运动的水下运载器纵向运动轨迹跟踪问题提出了一类非线性自适应控制方案。首先,直接采用非线性运动模型,在控制器设计过程中引入饱和函数,通过麦克劳林展开公式避免了俯仰角为小角度的假设限制;其次,考虑到运载器非线性运动模型很难给出精确的数学描述并且实际运载器系统存在模型误差,采用在线自适应方法近似逼近其非线性模型;最后,利用Backstepping方法设计了非线性自适应控制器,并利用Lyapunov理论证明了控制系统的稳定性。半实物仿真结果表明:在考虑测量噪声和参数不确定性的情况下,该算法对给出的3种轨迹的跟踪误差均小于0.5m,俯仰舵偏均小于15°,俯仰力矩均在105N.m量级。结果验证了本文提出的控制系统鲁棒性强,满足跟踪性能要求。

For the underwater vehicle trajectory tracking with strong nonlinearity and large pitch angle movement,a class of nonlinear adaptive control schemes were proposed in this paper.Firstly,the nonlinear movement model was adopted directly,a saturation function was induced in the process of controller design,and the assumption limit that the pitch angle was a small-angle was broken through the Maclaurin expansion formula.Then,taking into account that the precise nonlinear motion model of the vehicle was difficult to establish and there were many modeling errors in the actual vehicle model,the online adaptive method was used to approximate the nonlinear model.Finally,a nonlinear adaptive controller was designed by using Backstepping method,and its stability was proved by Lyapunov’s theory.The hardware-in-the-loop simulation results show that the tracking errors of all three types of tracks given in the paper are less than 0.5 m,the pitch rudder partials are less than 15°,and the pitch moments are within 105 N·m order of magnitude in consideration of measurement noises and parameter uncertainties,These results prove that the control algorithm in this article has a strong robustness and can meet the requirement of tracking performance.