柔顺宏微夹持系统动态耦合力/位移的分层协同控制方法研究

In cross-scale and variable-posture manipulation tasks, the simultaneous control of the movement and the gripping force associated with the posture of the manipulated object is required. However, the macro-micro gripping system presents the electromechanical and rigid-flexible coupling properties. Therefore, the macro motion is apt to excite the elastic vibration of the compliant microgripper, and the vibration on the left and right gripping arms cannot be exactly the same. Under the application background of micro-electromechanical assembly, this project focuses on a macro-micro gripping system driven by the voice coil motor and the piezoelectric stack actuator. The nonlinear modeling and control method considering the force/displacement coupling characteristic of the system are explored. In particular, a dynamic coupling force/displacement model including the motion characteristics of the macro stage, the driving characteristics of the piezoelectric stack actuator and the flexibility of compliant mechanisms is proposed. Moreover, the dimension reduction and decomposition theories for the high-dimension system are concerned. Based on the system model, a synchronous impedance control strategy for coordinating the left and the right gripping arms and a collaborative control method to cooperative the macro stage and the compliant microgripper are developed. Finally, experiments are performed to verify the system model and the control method. Considering that the proposed system model includes the derivative elastic vibration, the control strategy synchronously regulate the left and the right gripping arms, and the control method coordinate the macro stage and the compliant microgripper, the limitations of the existing system model and the control method are avoided. In addition, this project can improve the control accuracy and stability of the macro-micro gripping system, and provide the theoretical basis for high-precision, cross-scale and variable-posture micromanipulation.

跨尺度变姿态微操作任务需要同时控制被操作对象位姿相关的运动与夹持力，然而宏微夹持系统的机电、刚柔耦合导致大范围宏运动极易激起柔顺微夹持器的弹性振动，并且左、右夹持臂上的振动也难以完全一致。本项目以微机电系统领域的微小零件装配为应用背景，探究音圈电机和压电致动器联合驱动的宏微夹持系统的非线性建模及控制方法。具体研究内容有：建立包含宏动平台运动特性、压电致动器驱动特性和柔顺机构柔性的动态耦合力/位移模型，并研究高维系统模型降维与解耦；在系统模型的基础上设计统筹左、右夹持臂相互配合的同步阻抗控制策略，设计协调宏动平台和柔顺微夹持器配合工作的分层协同控制方法；系统模型与控制方法的实验验证。通过以上研究，突破现有系统模型不涉及衍生弹性振动、现有控制策略难以同步左、右夹持臂以及难以协调宏动平台和微夹持器配合的局限性，从而提高宏微夹持系统控制精度与稳定性，为高精度、跨尺度变姿态微操作提供理论基础。

宏微夹持系统在微操作及微装配任务中发挥着极其重要的作用，但因其机电、刚柔耦合特性，大范围宏运动极易激起柔顺机构弹性振动，增加系统操控难度。本项目围绕宏微夹持系统构建、动力学建模和精密控制展开研究，旨在提高系统控制精度和稳定性。.系统构建方面：针对面向跨尺度变姿态微操作任务的宏微夹持系统，考虑其稳定性、精确性和快速性性能需求，搭建了由压电驱动器、柔顺微夹持器、多自由度运动平台、激光位移传感器和应变力传感器等构成的宏微夹持系统。.动力学建模方面：利用具有非凸和非奇对称特性的死区算子加权叠加来描述压电驱动器非对称迟滞特性，利用伪刚体模型、柔度矩阵法和有限元法建立柔顺机构变形模型，并结合拉格朗日方程得到了宏微夹持系统的整体动力学模型。迟滞模型平均误差仅为0.063微米，动力学模型辨识度为93.6%。.精密控制方面：在所建系统模型的基础上，设计基于迟滞逆模型的前馈控制器对压电驱动器进行迟滞补偿，设计PID控制、滑模变结构控制和H无穷控制对宏动平台运动和微夹持器输出位移与夹持力进行精密控制及弹性振动抑制。运动位移和夹持力跟踪误差的均方根误差可达0.067微米和0.087毫牛。宏运动引起的弹性振动幅值减少52.0%(从2.5微米减少到1.2微米)，残余振动的衰减时间缩短66.7%(从201毫秒降低到67毫秒)，验证了控制方法的有效性，提高了系统操作精度和稳定性。.项目的实施为宏微夹持系统的高精密驱动和控制技术提供了相关理论基础和有益探索，具有重要的理论意义和明确的工程应用前景，将促进我国微机电系统领域的研究和相关产业的发展，并对宏微夹持系统的实际应用起到推动作用。