基于海流观测的欠驱动AUV自适应反演滑模轨迹跟踪  

Adaptive Backstepping Sliding Mode for Underactuated AUV Trajectory Tracking Based on Ocean Current Observer

作　　者：刘丽萍 王红燕 Liu Liping;Wang Hongyan(School of Electrical and Information Engineering,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学电气自动化与信息工程学院,天津300072

出　　处：《天津大学学报（自然科学与工程技术版）》2020年第7期745-753,共9页Journal of Tianjin University：Science and Technology

基　　金：国家自然科学基金资助项目(61773279);天津市科技计划资助项目(19YFHBQY00040).

摘　　要：欠驱动自主水下航行器AUV在定深的海域中航行,其模型水动力参数存在不确定性,同时还遭受海流等外来因素干扰,对欠驱动AUV的轨迹跟踪精确带来极大的挑战.本文研究海流环境中欠驱动AUV水平方向上的轨迹跟踪控制问题,通过定义固定坐标系和随体坐标系间的转化关系,将海流速度引入欠驱动AUV运动学和动力学方程,建立海流环境中欠驱动AUV的运动学模型和动力学模型;结合期望轨迹得到欠驱动AUV的轨迹跟踪误差方程.在控制器的设计过程中引入自适应率,得到AUV水平面轨迹跟踪的自适应反演滑模轨迹跟踪控制器(ABSMC),同时为降低海流因素对AUV航行轨迹带来的偏差,设计海流观测器对环境中海流速度进行估计.仿真结果表明,该控制器可实现对由水动力参数不确定和外界时变干扰共同组成的系统总不确定性的估计,并弥补传统反演滑模控制理论中需要精确的模型参数和扰动信息的不足,且海流观测器可提升AUV轨迹跟踪的精度.在理论上证明了由海流观测器和轨迹跟踪控制器共同组成的AUV级联控制系统为全局渐进稳定;仿真对比结果显示所提出的基于海流观测的自适应反演滑模控制器能够克服欠驱动AUV模型中水动力参数不确定性、海流干扰及其他未知干扰的影响,跟踪性能优于基于海流观测的反演轨迹跟踪控制器(BTC).The hydrodynamic parameters are uncertain when the underactuated autonomous underwater vehicle(AUV)sails with a certain depth in the ocean,and the underactuated AUV is also disturbed by external disturbances such as ocean currents. It poses a major challenge to trajectory tracking accuracy. This paper studies the trajectory tracking control problem of underactuated AUV in the horizontal plane under the ocean current environment. The current velocity is applied to the kinematics and dynamics equation by specifying the transformation relationship between an inertial reference frame and a body-fixed reference frame,and then the kinematic model and dynamic model of underactuated AUV with current can be calculated. The trajectory tracking error equation can be obtained in conjunction with the desired trajectory. The adaptive backstepping sliding mode controller(AB-SMC)for AUV horizontal trajectory tracking is designed by adding an adaptive rate. Moreover,an ocean current observer is devised to measure the ocean current velocity to reduce the navigation trajectory deviation of the actual AUV trajectory. The simulation results show that AB-SMC realizes the estimation of total uncertainties consisting of hydrodynamic parameters uncertainties and external time-varying disturbances and make up for the shortage of the precise model parameter and disturbance information in traditional backstepping sliding mode controy theory. And the ocean current observer can improve the tracking accuracy of the underactuated AUV. Theoretically,the whole AUV cascade control system consisting of AB-SMC and the ocean current observer is globally asymptotically stable. The simulation comparison diagrams show that the proposed AB-SMC based on ocean current observer can resolve the effects of hydrodynamic parameter uncertainty,ocean current disturbances,and other unknown disturbances. Furthermore,its tracking efficiency is better than the ocean current observer-based backstepping trajectory tracking controller(BTTC).

关 键 词：自主水下航行器 轨迹跟踪 自适应反演滑模控制 海流观测器 

分 类 号：TP242.6[自动化与计算机技术—检测技术与自动化装置]