基于冗余驱动和主动阻尼的大行程柔顺并联机构系统设计与运动控制研究

Compliant parallel manipulator (CPM) based on the distributed-compliance design is capable of achieving long stroke backlash-free motion, which has broad application prospects in fields of optical positioning, cell manipulation, precision machining. However, the inherently low stiffness and underdamping characteristics of the distributed-compliance structure makes the CPM suffer from slow response, poor anti-interference ability and easy to vibration when the work speed of the manipulator is high, which severely reduced the motion accuracy and work efficiency of the system. This proposal intends to carry out system design and motion control research on the distributed-compliance CPM to improve the overall performance of the system. The critical research issues to be investigated include: configuration design of a long stroke CPM based on redundant actuation, so as to improve the structure stiffness and response speed of the manipulator; design and performance analysis of an electromagnetic damper which acting at the end-effector of compliant parallel manipulator, so as to improve the damping characteristics of the system; dynamics coupling characteristic analysis and active damping planning of the CPM, so as to optimal the system damping by adjusting the excitation current of the damper; and high-precision closed-loop motion control algorithm for the CPM; so as to suppress the effects of structural vibration and external disturbance on the motion accuracy of the system. This research proposal is attempting to provide theoretical and technical support for the design and control of novel high-precision motion platforms, which has important theoretical significance and practical value.

基于分布式柔度结构设计的柔顺并联机构能够实现大范围无间隙的运动，在光学定位、细胞操作、精密加工等高精度运动场合具有广阔的应用前景。然而，分布式柔度结构固有的低刚度、欠阻尼特性，导致此类大行程柔顺并联机构在高速运动时呈现出响应速度慢、抗干扰能力差、结构易振动等缺点，严重降低了机构的运动精度和工作效率。本项目拟对面向高速运动的大行程柔顺并联机构开展系统设计和运动控制研究：从大行程柔顺并联机构的构型方式出发，通过引入冗余驱动支链提高机构的刚度和响应速度；设计直接作用于柔顺并联机构末端平台的主动电磁阻尼器，改善机构的阻尼特性；基于柔顺并联机构的机-电-磁耦合动力学模型研究阻尼规划算法，实现系统动态阻尼的最优配置；研究柔顺并联机构的闭环运动控制策略，抑制结构振动和外扰动对运动精度的影响。本项目的研究将极大地提高大行程柔顺并联机构工作时的精度和效率，为新型精密运动平台的设计和控制提供理论和技术支撑。

随着精密光学、生物和遗传工程、显微观测以及航空航天等领域的快速发展，要求新型的精密运动机构能够在厘米级的运动范围内提供纳米级的运动精度。柔顺并联机构通过结构的弹性变形来传递力和运动，彻底消除了运动副传动过程中的空程和机械摩擦，可以获得极高的位移分辨率和重复定位精度。然而传统大行程柔顺并联机构的低刚度、欠阻尼特性，导致其在高速运动状态下呈现出响应速度慢、调整时间长、结构易振动等缺点。. 本课题开展了基于冗余驱动和主动阻尼的大行程柔顺并联机构系统设计和运动控制研究：（1）提出了一种新型基于冗余驱动的4-PPR柔性并联机构的构型方案。该机构通过引入冗余驱动支链，提高柔性并联机构的输出刚度、降低电机的峰值力要求和电机动子质量，有利于提高柔性并联机构的响应速度。（2）搭建了4-PPR柔性并联机构的系统样机，采用结合模型信息的自抗扰控制算法对柔性并联机构进行了定位和轨迹跟踪控制实验，实验结果表明4-PPR柔性并联机构可以在±2.5mm×±2.5mm×±2.5°的范围内达到80nm的平动分辨率和0.28″的转动分辨率，轨迹跟踪误差比小于0.1%。（3）设计了主动电磁涡流阻尼器使大行程柔顺并联机构的系统阻尼能够在大范围内精确调节，开发了基于复合非线性反馈的主动阻尼控制算法，实现了高精度的定位控制。. 本课题的研究极大的提高柔顺并联机构在执行大范围高速精密操作时的效率和精度，可以为新型精密运动平台的设计提供理论和技术支撑。