65米射电望远镜副面调整控制系统设计与控制策略研究

发布时间：2018-01-18 08:01

本文关键词：65米射电望远镜副面调整控制系统设计与控制策略研究　出处：《燕山大学》2014年博士论文　论文类型：学位论文

【摘要】：65米射电望远镜采用Stewart型并联机构对副面位姿进行调整,以实现指向误差修正和馈源转换。针对如何提高调整机构的稳定性、准确性和快速性,设计了调整机构的控制系统并对控制策略进行了深入的理论分析和实验研究,主要内容如下：分析系统广义坐标与动平台以及驱动分支速度、加速度的映射关系,计算各构件的偏速度和偏角速度。通过对基座运动引起的各构件速度、加速度进行分析,得到基座运动引起的各构件惯性力。采用具有高实时性特点的Kane方法分别对基座固定和运动情况下的调整机构进行动力学建模,采用数值分析和Adams软件仿真的方法,对上述两种情况下系统动力学性能进行对比分析。在PID反馈控制基础上,设计能够实现速度、加速度和粘性摩擦力补偿的前馈补偿器,并对其工作原理和稳定性进行了分析。建立驱动分支动力学模型,通过S曲线跟踪响应对控制系统性能进行验证。使用Simulink和SimMechanics分别建立调整机构的多轴运动控制系统和机构模型,通过圆轨迹动态跟踪对控制系统的跟踪精度进行了仿真分析。提出调整机构姿态精度监测方法并给出误差超差判别公式。通过对磁尺回零和回零传感器回零的原理进行分析,提出利用磁尺和回零传感器相互校正实现零点重建的方法,并对零点重建精度进行实验分析。根据机构自由度数大于任务自由度数的特点,提出基于冗余自由度的调整机构容错策略,并分析容错后机构的工作空间。提出不规则工作空间边界的数字化识别方法,以扩大机构的工作范围。通过对调整机构功能需求分析,采用模块化思想设计包含伺服驱动单元、直线运动单元、低压控制单元和运动控制单元的电气控制系统。通过COM组件技术、ActiveX控件技术和动态链接库技术设计调整机构的软件系统,并利用CUDA并行计算技术进行调整机构轨迹规划,大大提高系统的实时性。建立Client/Server网络控制结构,通过TCP/IP协议实现调整系统的远程控制。参考国标GB/T1741.2-2000中数控机床重复定位精度检测和评定方法,提出一种包含耦合重复定位精度的并联机构重复定位精度测量和评定方法,并使用激光跟踪仪对机构的重复定位精度进行测量分析。且对驱动分支和调整机构的动态跟踪精度分别进行测试和分析,对基于冗余自由度的调整机构容错策略的可行性进行实验验证。
[Abstract]:The Stewart parallel mechanism is used to adjust the position and pose of the sub-plane for the 65m radio telescope to correct the pointing error and to convert the feed. The stability, accuracy and rapidity of the adjustment mechanism are improved in the light of how to improve the stability, accuracy and rapidity of the adjustment mechanism. The control system of the adjusting mechanism is designed and the control strategy is analyzed theoretically and experimentally. The main contents are as follows: The mapping relationship between the generalized coordinates of the system and the moving platform as well as the velocity and acceleration of the driving branch is analyzed. The partial velocity and the angular velocity of each component are calculated. The velocity and acceleration of each component caused by the motion of the base are analyzed. The inertial force of each component caused by the motion of the base is obtained. The Kane method with high real-time characteristics is used to model the dynamic model of the adjusting mechanism under the fixed and moving conditions of the base respectively. By using numerical analysis and Adams software simulation, the dynamic performance of the system is compared and analyzed. On the basis of PID feedback control, a feedforward compensator is designed to compensate for velocity, acceleration and viscous friction. The principle and stability of the feedforward compensator are analyzed, and the dynamic model of driving branch is established. The performance of the control system is verified by the S-curve tracking response. The multi-axis motion control system and the mechanism model of the adjusting mechanism are established by using Simulink and SimMechanics, respectively. The tracking accuracy of the control system is simulated and analyzed by circle trajectory dynamic tracking. In this paper, the attitude accuracy monitoring method of adjusting mechanism is put forward, and the discriminant formula of error overshoot is given. The principle of zero return of magnetic ruler and zero return sensor is analyzed. A method of 00:00 reconstruction using magnetic ruler and zero return sensor is proposed, and the precision of 00:00 reconstruction is analyzed experimentally. According to the characteristics that the degree of freedom of mechanism is greater than the number of freedom of task. A fault-tolerant strategy based on redundant degrees of freedom is proposed, and the workspace of the mechanism after fault tolerance is analyzed. A digital recognition method of irregular workspace boundary is proposed to enlarge the working range of the mechanism. By analyzing the functional requirements of the adjusting mechanism, the modular design includes servo drive unit and linear motion unit. The electric control system of low voltage control unit and motion control unit. The software system of adjusting mechanism is designed by COM component technology and dynamic link library technology. The CUDA parallel computing technology is used to adjust the mechanism trajectory planning, which greatly improves the real-time performance of the system. The Client/Server network control structure is established. The remote control of adjusting system is realized by TCP/IP protocol. Refer to the national standard GB/T1741.2-2000 NC machine tool repeated positioning accuracy detection and evaluation method. A method for measuring and evaluating the accuracy of repeated positioning of parallel mechanism is presented. The laser tracker is used to measure and analyze the accuracy of the repeated positioning of the mechanism, and the dynamic tracking accuracy of the driving branch and the adjusting mechanism are tested and analyzed respectively. The feasibility of the fault-tolerant strategy of the adjustment mechanism based on redundant degrees of freedom is verified experimentally.
【学位授予单位】：燕山大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TH751;TP273

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