【作者】 李兵；

【导师】 王丽梅；

【作者基本信息】 沈阳工业大学 ， 电力电子与电力传动， 2013， 博士

【摘要】 本文以国家自然科学基金资助项目“基于速度场的直接驱动XY平台任意轨迹规划与精密轮廓控制”(51175349)为背景，以永磁直线同步电机直接驱动X-Y运动平台伺服系统为研究对象，针对永磁直线同步电动机直接驱动的特点及其对伺服系统鲁棒性及轮廓性能的双重要求，提出一种基于方向场理论的X-Y平台速度规划与轮廓控制方法。首先，采用几何法构建了基于隐函式的圆形轨迹的速度场。由于圆形轨迹能够以隐函式表示，因此，采用几何法对平面内任意一点到期望轨迹的最短距离向量与切线向量分别进行计算，构建期望轨迹的速度场，为避免传统轮廓-跟踪控制方法对于时间的限制问题，消除“轨径缩减”的现象提供理论依据。分别对速度场的构建、轮廓误差的计算进行仿真分析。然后，针对NURBS参数曲线的任意性及其速度场难于构建的特殊性，提出采用方向场理论对直接驱动X-Y平台任意轨迹的初始速度进行间接规划。当初始轨迹为任意自由轨迹时，最短距离向量难以准确计算，因此，根据方向场理论，以划分网格的方式间接、离线规划期望轨迹的速度，将双轴协调控制问题转化为单轴速度控制问题。并且针对以方向场理论进行速度规划方法的正确性及有效性进行分析。在速度规划的框架之上，分别在理想控制条件下及扰动存在的两种情况下，对X-Y平台伺服系统进行传统PI控制仿真研究。最后，针对由方向场理论进行速度规划方法的特殊性及X-Y平台伺服系统易受非线性、周期性扰动及参数摄动等不确定性因素的影响，提出一种基于Lyapunov函数的改进PI扰动补偿自适应轮廓控制方法。根据Lyapunov稳定性理论，以各单轴速度误差为控制目标，设计基于Lyapunov函数的速度控制器，直接提高系统的轮廓精度。针对系统存在的负载扰动及参数摄动，采用改进PI扰动补偿自适应控制方法，实时调整扰动补偿器的控制增益，实现扰动补偿，提高系统的鲁棒性。并分别针对上述轮廓控制方法进行仿真研究。本文搭建了永磁直线电机直接驱动X-Y平台轮廓控制系统，在以方向场理论进行速度规划的基础之上，分别对传统PI控制，基于Lyapunov函数的速度控制方法(LVFC)，基于Lyapunov函数的传统PI扰动补偿方法(LVFC/PDCC)及基于Lyapunov函数的改进PI扰动补偿自适应控制方法(LVFC/IPDCAC)，在速度闭环情况下进行对比实验研究，验证了本文所提出的速度规划方法与控制策略的理论研究的有效性。更多还原

【Abstract】 The paper is supported by National Natural Science Foundation of China “TrajectoryPlanning and Accurate Contour Control based Velocity field for Direct Drive X-Y Table”(NO.51175349). In this paper, permanent magnet linear synchronous motor (PMLSM)direct drive X-Y motion table servo system is the main study object. For the characteristicof direct drive system and requirements of robustness and contour performance for theX-Y table servo system, a method that combines velocity planning and contour controlmethod based on direction field theory was proposed.Firstly, a geometric method was used to construct the velocity field for the circlecontour. For constructing the velocity field, calculate the distance vector and tangent vectorrespectively. To enhance the contour performance, avoid time restraint problem for thetraditional contour-tracking contour control method and eliminate the “radial reduction”phenomenon, a velocity planning method was adopted to transform contour-trackingbiaxial coordination control into velocity control of the single axis. Velocity fieldconstruction and contour error calculation was studied by simulation.Secondly, in order to extend velocity field to contours represented in NURBS form,the direction field method was adopted for the direct drive X-Y table velocity planning.For the line or circle contour following tasks, it is easy to find the corresponding distancevector, whereas it is not the case for the free form contour following task. For planningdesired velocity of the system and transforming biaxial coordination control into thevelocity control of single axis, a novel meshing method based on direction field was usedto construct NURBS curve velocity field. Considering the ideal control condition and theexistence of load disturbances, the traditional PI control for X-Y table contour controlsystem was studied by simulation.Last, for the influences of nonlinear, periodic disturbances and parameter changes, animproved PI disturbance compensation adaptive contour control method based onLyapunov function the direction field was proposed. Firstly, based on Lyapunov stability theorem, a velocity controller was designed based on Lyapunov function to reduce thevelocity error of the single axis. Secondly, in order to further enhance the robustperformance and improve the contour performance, an improved PI disturbancecompensation adaptive controller was used to compensation the disturbances force causedby the uncertainties of parameter changes and load disturbances of system. The abovecontrol methods were studied by simulation.Contour control system for direct drive X-Y experimental table was built. Based onthe velocity planning principle, traditional PI control method based on direction field, aLyapunov function velocity field control (LVFC), PI disturbance compensation controlbased on Lyapunov function velocity field control (LVFC/PDCC) and Improved PIdisturbance compensation adaptive control based on Lyapunov function velocity fieldcontrol (LVFC/IPDCAC) were compared in the experiments under the circumstances ofthe loop. The comparative experimental results verified the validity of velocity planningmethod and control strategies proposed in theoretical analysis and simulation.更多还原