【作者】 齐雪；

【导师】 张利军；

【作者基本信息】 哈尔滨工程大学 ， 系统工程， 2012， 博士

【摘要】 自主水下机器人(AUV)运动控制系统是一个受外界扰动强,且具有强非线性、耦合性、欠驱动性、不确定性的动态系统。因此,AUV运动控制问题属于典型的非线性系统控制理论的研究范畴。研究AUV运动系统的非线性控制问题具有重要的理论价值和现实意义。为此,本文基于自适应鲁棒非线性控制理论,探讨AUV运动系统的非线性控制问题,旨在提高AUV运动系统的动态品质。本文在系统地分析了AUV控制系统非线性动态模型的基础上,分别研究了单个AUV路径跟踪问题和多AUVs分散式编队协调控制问题,具体研究工作如下：第一,对AUV定深运动进行研究,建立了定深运动非完整模型,提出了基于反步法的自适应输出反馈控制器,该控制器在AUV缺少垂直推进器而只配备主推进器和水平舵的情况下,能够满足定深控制精度。由于控制器将反步法与神经网络和自适应律结合起来,能够补偿AUV运动系统中参数不确定性和非线性部分,因而对有界的外部扰动具有较强的鲁棒性。第二,针对近水面航行的AUV路径跟踪控制问题进行研究,在载体坐标系下建立AUV路径跟踪误差动力学模型,提出了基于神经网络的自适应输出反馈控制器。该控制方法克服了带波频干扰的系统输出信号进入控制环节所造成的驱动装置的破坏和燃料的浪费,同时还克服了过多测量装置带来的测量误差和测量噪声。该控制方法不需要精确的系统模型,对于系统内部参数变化、不确定性以及外部干扰具有很强的鲁棒性。第三,针对AUV路径跟踪控制问题,引入Serret-Frenet坐标系,并在此坐标系下建立路径跟踪误差动力学模型,提出了非线性鲁棒自适应控制器。该控制方法在保证闭环系统稳定性的同时,还充分考虑了AUV动态系统中存在的参数摄动值问题。通过设计鲁棒自适应律,从而有效补偿未知参数摄动值部分,提高了路径跟踪精度。通过采用视线角导航,使AUV根据目标点的变化而改变操舵行为,从而加快了AUV收敛到期望路径的速度。第四,在单个AUV路径跟踪的基础上研究了多AUVs编队协调控制问题。基于Lyapunov稳定性理论和图论知识提出了分散式编队协调控制器。该控制方法不仅适用于通讯畅通的多AUVs编队控制,还适用于存在通讯缺失和通讯时滞的多AUVs编队控制。针对存在通讯缺失和通讯时滞的编队协调控制问题,分析了整个系统上通讯缺失和通讯时滞的影响,给出了协调误差动态系统稳定的条件。最后通过理论证明和仿真结果表明所提出的控制方法的有效性。更多还原

【Abstract】 Autonomous underwater vehicle (AUV)’s dynamic system has strong external disturbances, nonlinearity, coupling feature, underactuated and a large number of uncertainties in water coefficients. Therefore, the control of AUV belongs to a class of typical nonlinear control research category. The research of AUV’s nonlinear control problem has important significance both in theory and practice. Therefore, based on the nonlinear adaptive robust control theory, this paper discusses the problem of nonlinear control of AUV to improve dynamic quality of AUV’s system. Based on the nonlinear system of AUV, this paper discuss the path following control of single AUV and distributed formation control of muti-AUVs, the research work are as follows:Firstly, for the problem of an AUV deep-set motion control, a nonholonomic motion model is set up and an adaptive output feedback controller based on backstepping technique is proposed. The precision of deep-set motion can be satisfied by the controller in lack of vertical thrusters and only with main thruster and level rudders. In addition, backstepping technique combinated with neural network adaptive laws not only can compensate the nonlinear part and the uncertainty parameters of the AUV, but also can make the controller robust to the external disturbance.Secondly, the path following control of AUV moving in shallow water area is discussed. In the body coordinate frame, the path following error dynamics of AUV in set up and an adaptive output feedback controller based on neural network is proposed. The significant disturbance due to wave motion will be introduced into the measurable output signals and will influence the actual position and attitude of AUV. If the wave disturbance enter into the control loop, it will cause increase of the output control, reduction of the control accuracy, waste of fuel and wear of actuators in serious situation. According to this problem, the proposed controller can filter out the disturbance from the output signals and make them unable to enter control loop. This control method does not need the accurate model of system. Simulation experiment results show that the proposed controller has good adaptability for viscous damping coefficients and unknown nonlinear structure and strong robustness for uncertain additional quality and changing disturbance.Thirdly, for the path following control of AUV, the Serret-Frenet coordinate frame is introduced. In the Serret-Frenet coordinate frame, the path following error dynamics of AUV in set up and a nonlinear robust adaptive controller is proposed. The control method not only can stabilize the closed-loop system, but also fully considered the parameters’ time-varying properties which cause the difference between the nominal value and the actual value of the parameters in AUV’s dynamic system. The difference is called parameter perturbation value. The control accuracy will be improved by the proposed robust adaptive control law which is used to compensate parameters’perturbation. By introducing the line-of-sight (LOS) angle, the movement behavior of AUV can be changed according to the target. The AUV can move to the path fast by the LOS navigation.Finally, based on the path following control of a single AUV, the formation coordinated control of muti-AUVs is studied in this paper. The proposed control method based on the Lyapunov stability theory and graph theory. The control method is not only applicable to communication unimpeded, but also applicable to communication failures and delays on the performance of the overall AUV formation. The impact of communication failures and delays on the overall system performance is analyzed. Conditions are derived under which the cooperation errors dynamics is stable. Finally, the theoretic proof and simulation results show that the proposed control method is effective on formation coordinated control of muti-AUVs.更多还原