主被动相融合的抗冲击柔性关节及其控制研究

发布时间：2018-08-10 18:10

【摘要】：近年来,柔性关节由于具有较好的抗冲击、容易实现精确的力控制,同时负载/自重比较大,在轻型机械臂、步行机器人、机械外骨骼等领域被广泛应用。本文在“新概念智能操控载荷技术”项目的支持下,针对轻型机械臂的应用需求,提出了一种高度集成的抗冲击柔性关节,其采用串联弹性驱动技术来实现被动柔性和力矩感知功能,并在此基础上对关节开展主动柔顺控制以及抗冲击特性等研究。首先,根据设计指标要求,完成了柔性关节的总体结构设计。确定了“电机+减速器+弹性元件+负载”的设计方案,对关节内部驱动传动系统、传感系统以及失电制动器的具体结构进行了详细设计;为实现关节的被动柔性,设计了一种新型串联弹性元件,同时可以用其反馈关节力矩信息,利用Workbench软件提供的DOE试验设计法对弹性元件的形状进行了优化分析,使其刚度满足关节的设计要求;对关节内部的关键承载零件进行了强度校核。其次,建立了柔性关节的动力学模型,并完成了主要参数的辨识。通过将串联弹性元件简化为无阻尼的线性扭簧,建立了柔性关节的简化动力学模型;在动力学模型的基础上,对柔性关节的相关特性进行了理论分析。采用静加载的方式对关节刚度进行了辨识;利用遗传算法辨识得到了关节的LuGre静态摩擦模型,并提出了一种简化线性摩擦模型;通过电机控制输入量PWM值和与其对应的电机输出力矩之间的关系,计算得到了电机力矩系数。然后,研究了柔性关节的位置控制、力柔顺控制策略。针对柔性关节的位置控制,制定了PD控制策略和PD+反步法分层控制策略,并利用Simulink对两种算法进行了仿真分析;针对柔性关节的力柔顺控制,制定了力矩伺服控制策略和阻抗控制策略,利用ADAMS和Simulink对相应控制策略进行了联合仿真验证;对柔性关节进行了静态和动态冲击仿真分析。最后,搭建了柔性关节实验平台,对柔性关节进行性能实验研究。在不同负载下,通过对柔性关节进行了不同频率、不同幅值正弦信号跟踪实验,验证了位置控制算法的有效性;通过对柔性关节进行力矩跟踪实验、零力矩控制实验和扰动及碰撞实验,验证了力柔顺控制策略的有效性;通过对柔性关节进行静态和动态冲击实验,测试了关节内部弹性元件的抗冲击特性。
[Abstract]:In recent years, flexible joints have been widely used in light manipulators, walking robots, mechanical exoskeletons and other fields because of their good impact resistance, easy to achieve accurate force control and large load/deadweight ratio. A highly integrated anti-impact flexible joint is proposed, which uses series elastic drive technology to realize passive flexibility and torque sensing. On this basis, active compliance control and anti-impact characteristics of the joint are studied. Firstly, the overall structure design of the flexible joint is completed according to the requirements of design indicators. In order to realize the passive flexibility of the joint, a new series elastic element is designed, which can be used to feedback the joint torque information and the DOE provided by Workbench software. The shape of the elastic element is optimized and analyzed by the experimental design method to make its stiffness meet the design requirements of the joint. The strength of the key load-bearing parts inside the joint is checked. Secondly, the dynamic model of the flexible joint is established and the main parameters are identified. A simplified dynamic model of the flexible joint is established. Based on the dynamic model, the relevant characteristics of the flexible joint are analyzed theoretically. The torque coefficient of the motor is calculated by the relationship between the PWM value of the motor control input and the corresponding output torque of the motor. Then, the position control and force compliance control strategies of the flexible joint are studied. The algorithm is simulated and analyzed; the torque servo control strategy and impedance control strategy are formulated for the force compliance control of flexible joints; the corresponding control strategy is verified by joint simulation using ADAMS and Simulink; the static and dynamic impact simulation analysis of flexible joints is carried out. Finally, the experimental platform of flexible joints is built to control the flexibility. The performance of the joint is experimentally studied. The effectiveness of the position control algorithm is verified by sinusoidal tracking experiments with different frequencies and amplitudes under different loads. The torque tracking experiment, zero torque control experiment and disturbance and collision experiment are carried out to verify the force compliance control strategy. The validity of the flexible joint was tested by static and dynamic impact tests.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP242

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