【作者】 韩冰；

【导师】 赵国良；

【作者基本信息】 哈尔滨工程大学 ， 控制理论与控制工程， 2004， 博士

【摘要】 机械系统的欠驱动特性是指系统控制输入向量空间的维数小于系统广义坐标向量空间维数的情况。该系统的特点是可用维数较少的输入控制其在维数较多的广义坐标空间内的运动。对欠驱动系统的研究,不仅可以降低系统的费用及重量,而且当实际系统中出现某执行装置失灵时,可以在欠驱动的概念基础上,利用未失灵的执行装置继续对系统进行有效的控制,降低因部分元件发生故障而对系统整体性能的影响。因此,近几年对于欠驱动机械系统的控制研究得到格外关注。 本文以常规水面船舶为研究对象,指出其在特定的控制要求下,系统具有欠驱动特性,并且针对欠驱动船舶不同控制要求下的非线性控制问题进行了深入的研究。 本文利用拉格朗日能量法推导了船舶6自由度非线性运动方程。在此基础上,通过增加简化条件,获得常规船舶水平面运动方程。采用微分几何的方法证明了欠驱动船舶水平面运动系统属于二阶非完整系统;同时证明了系统是强可达的及小时间局部可控的;并从能量的角度,揭示出该系统具有无源性。 对于欠驱动船舶动力定位和自动泊位的镇定控制律设计,基于σ变换方法的思想,通过在系统中增加附加收敛控制项,控制系统的整体收敛速率,获得具有指数收敛速率的时变光滑反馈镇定律,实现了欠驱动船舶的镇定控制。该方法同样适用于经微分同胚变换后获得的二阶系统方程组。该方法克服了其它方法中控制律不连续和对系统状态存在限制条件的缺陷。 对于欠驱动船舶的直接航迹控制问题,证明了欠驱动船舶直接航迹控制系统属于微分平滑系统。采用动态扩张反馈线性化的方法,获得欠驱动船舶直接航迹控制器,实现了欠驱动船舶航迹误差和航向误差全局渐近指数镇定。该方法解除了其它方法中要求角速度持续激励的假设条件。 证明了尾部带有两个螺旋桨推进器的欠驱动气垫船的航向—侧漂综合系统是可控的,并借鉴齐次方法中设定速度场的控制思想,并结合反步法设计更多还原

【Abstract】 The underactuation of mechanical systems means that the dimension of the control vectors of systems is less than that of the configuration vector of systems. The feature of underactuated mechanical systems is that the motion of mechanical systems in configuration space can be controlled by the fewer independent control inputs than the dimension of configuration space. It implies that underactuated mechanical systems can reduce the cost and the weight of systems. Moreover, the idea of underactuation can be used to control systems in which some components are failed during operation so that the system is also be controlled by the unfailed components effectively and the influence on the system performance caused by failures of system components can be decreased. Therefore, the more and more attention has been paid on underactuated mechanical systems in recent years.The focused object is surface vessel. It is pointed out that the underactuate characteristic is emerged under special control aims. So for the different control aims, the problem on nonlinear control of the underactuated surface vessel is focused in this dissertation.The 6 degrees of freedom dynamic and kinematic nonlinear models of surface vessels are derived based on Lagrangian energy method and some assumptions, the dynamic and kinematic models of surface vessels in horizontal plane are obtained. It is proved that the motion control system of underactuated surface vessels in horizontal plane belongs to the second-order nonholonomic system. The strong accessibility and small time local controllability of the system are proved. From the energy view point, the passivity of the system is revealed.For the stabilization control law design using on the dynamic positioning and position mooring of underactuated surface vessels, based on the method of σ -process, a convergence control item is added in the original equations to control the converge rate of the whole system. A smooth time-varying feedback stabilization law with exponentially convergence rate is obtained. The aim of stabilization control of underactuated surface vessels is achieved. The method canalso be used for the second-order state equations which obtained by diffeomorphism transforming from the dynamic and kinematic models of surface vessels in horizontal plane. The proposed method is superior to the other methods which stabilized the system with discontinuous control law and some limitation on the variation of states.For the direct path tracking control of underactuated surface vessels in horizontal plane, the system is proved to be a differential flatness system. The method of dynamic extended feedback linearization is adopted. Then the control law is derived such that the tracking error and heading error with respect to the planned path could be stabilized exponentially asymptotically and globally. The method relaxes the assumption of persistent exciting in yaw rate required in other methods.The controllability of heading-drift system of underactuated hovercrafts with two aft propellers is proved. Then adopting the concept of desired speed vector field in homogeneous approach, combining the backstepping approach, a new method for hovercrafts heading-drift control law design is proposed that keeps hovercrafts heading constant as well as minimizes the lateral movement of hovercrafts.Simulation tests are carried out to illustrate the effectiveness of the proposed control laws for different control aims. At the same time, the validity of the proposed control law is verified by the simulation tests.更多还原