【作者】 王亮；

【导师】 刘国海；

【作者基本信息】 江苏大学 ， 电气工程（专业学位）， 2017， 硕士

【摘要】 无人水面艇可在复杂海洋环境中执行任务,在自主侦察、监视、猎雷、救援、环境监测等方面性能卓著,近年来得到了世界各国越来越多的关注。然而,水面艇航速和装载质量的不断变化会引起模型中参数的摄动,海风、海浪和海流等环境因素给模型带来了外界干扰。参数摄动、外界干扰和建模误差共同造成了水面艇模型的不确定性,严重影响着水面艇控制系统的鲁棒性。因此,研究无人水面艇的鲁棒控制具有重要的理论价值和实际意义。本文的主要研究工作及创新性成果主要包括:针对无系统约束无人水面艇的鲁棒控制问题,提出基于复合误差(跟踪误差和估计误差)驱动扩展状态观测器的自抗扰控制器。复合误差能使控制的响应更加平滑,可在不激励高频未建模动态情况下获得较小的估计误差和跟踪误差。该扩展状态观测器同时利用了估计误差和跟踪误差来处理扰动,所以该控制是一种前馈反馈复合控制,充分利用前馈控制和反馈控制来抑制系统的扰动。通过理论分析和仿真实验说明了该控制器的鲁棒性。针对存在位置和速度约束无人水面艇的鲁棒控制问题,提出基于轨迹线性化的无人水面艇tube预测控制。该鲁棒预测控制由线性反馈控制和基于参考模型的预测控制组成,基于参考模型的预测控制使得参考轨迹收敛到期望轨迹,线性反馈控制确保水面艇真实轨迹包含在以参考轨迹为中心的小领域内。通过轨迹线性化得到线性时变的预测模型,降低非线性预测控制的计算复杂度。采用Lyapunov理论证明并通过仿真实验说明该控制器的可行性和鲁棒性。针对存在控制约束无人水面艇的鲁棒控制问题,提出基于无人水面艇非线性连续时间模型的tube预测控制。该tube预测控制由非线性反馈控制和基于连续时间模型的双模预测控制组成,基于连续时间模型的双模预测控制用来保证参考系统的渐进稳定,而非线性反馈控制可保证真实轨迹包含在以参考轨迹为中心的管子内。理论分析和仿真结果说明在保证约束的情况下,该控制器具有较好的鲁棒性能。更多还原

【Abstract】 Unmanned surface vessel(USV)can perform tasks in complex marine environments,it has obtained more and more attention all over the world for its outstanding performance in autonomous reconnaissance,surveillance,minehunting,rescue,environmental monitoring and so on.However,the continuous change of the speed and the weight of USV cause the perturbation of model parameters,sea winds,sea waves,ocean currents and other external environmental factors bring external disturbance to the model.The perturbation of model parameters,external disturbance and modeling errors cause the uncertainty of USV model,which seriously affects the robustness of the control system.Therefore,it is of great theoretical and practical significance to research the robust control of USV.The main contributions and innovative achievements are stated as follows:In order to solve the problem of robust control for USV with no system constraints,a disturbance rejection control using composite-errors-based(tracking error and estimation error)extended state observer is proposed.The composite error can improve the smoothness of control response,and it also can achieve small disturbance estimation error and small trajectory tracking error without exciting high-frequency unmolded dynamics.The extended state observer utilizes both estimation error and tracking error to deal with disturbance,so the proposed control is a feedforward feedback composite control,and makes full use of feedforward control and feedback control to suppress the system disturbance.Theoretical analysis and simulation results illustrate the robustness of the proposed control.According to the USV model with position and velocity constraints,a trajectory-linearization based tube model predictive control(MPC)is proposed.The tube MPC includes a linear feedback control and a nominal model based MPC.The nominal model based MPC makes the nominal trajectory converges to the desired trajectory,and the linear feedback control guarantees the USV’s actual trajectory being contained in a small area centered at the nominal trajectory.Using trajectory linearization gets the linear time-varying prediction model,which can reduce the computational complexity of nonlinear MPC.The feasibility and robustness of the proposed control is demonstrated by Lyapunov theory and simulation results.According to the USV model with control constraints,a nonlinear continuous time model based tube MPC is proposed.The tube MPC is composed of a nonlinear feedback control and a continuous-time model based dual-mode MPC,the continuous-time model based dual-mode MPC guarantees asymptotical stability of the nominal system,and the nonlinear feedback control can ensure the actual trajectory is contained in a tube with the nominal trajectory as the center.Theoretical analysis and simulation results show that the proposed control has better robust performance when the constraint is guaranteed.更多还原