二自由度串联机械臂与简易手抓力控制研究

发布时间：2018-07-18 15:36

【摘要】：机械臂迫切要求适用于非结构化环境接触任务,与机械臂紧密相关的机械手抓也迫切要求灵巧抓取。本文围绕机械手抓抓取任务的安全牢稳和成本等问题,以及机械臂接触任务的柔顺和安全等问题,分别对基于虚拟力传感器的简易手抓力控制,以及二自由度串联机械臂力跟踪阻抗控制和力估计避碰控制进行了研究。首先,论文通过对课题的分析认识到:课题研究对象的共性是机械手抓和机械臂同为连杆机构,其运动、动力学建模方式相同;常见的简易机械手抓对称部分为平行四连杆机构,其实际自由度退化为一,可以施加简单的控制方式;基于力觉传感器的机械手抓成本昂贵,可以通过其他易测变量间接估计作用力;常见的机械臂接触任务需要同时满足不同方向的力控制和位置控制效果。依据以上认识将论文开展分为三个部分:机械手抓和机械臂的运动学、动力学模型建立基础;基于虚拟力传感器的简易手抓切换PID力控制;二自由度串联机械臂不同方向的力跟踪阻抗控制和力估计避碰控制。其次,论文针对课题开展的三个部分开展了以下具体研究内容:第一部分包括:二自由度串联机械臂的正、逆运动学和轨迹规划;简易手抓的运动学约束;运动-静力学二元性原则;连杆机构动力学模型。第二部分包括:简易手抓的关节空间开链动力学模型;依据运动-静力学二元性原则建立关节空间闭链动力学模型;驱动关节干扰力矩估计;依据虚位移原理估计夹持力。第三部分包括:机械臂动力学模型;逆动力学位置控制;位置内环阻抗控制;x轴方向力跟踪阻抗控制;y轴方向力估计避碰控制。最后,MATLAB-Adams仿真实验结果表明论文研究内容解决了机械手抓和机械臂的两类问题:一是基于虚拟力传感器的简易手抓力控制,解决了抓取任务的安全牢稳和成本等问题;二是不同方向的力跟踪阻抗控制和力估计避碰控制的结合,系统地解决了机械臂接触任务的柔顺、安全问题。
[Abstract]:Manipulators are required to be applied to unstructured contact tasks, and manipulators which are closely related to the manipulators also need dexterous grabbing. This paper focuses on the problems of the safety, stability and cost of the grasping task of the manipulator, as well as the flexibility and safety of the robot arm contact task, and respectively controls the simple hand grip force based on the virtual force sensor. The impedance control and force estimation control of two degrees of freedom series mechanical arm are studied. First of all, through the analysis of the subject, it is recognized that the common character of the research object is that the manipulator and the manipulator are the same linkage mechanism, and their motion and dynamics modeling methods are the same; The common simple manipulator gripping symmetry part is parallel four-bar linkage mechanism, its actual degree of freedom is reduced to one, can apply simple control mode, the manipulator based on force sensor is expensive, The force can be estimated indirectly by other easily measured variables, and the common contact task of manipulator needs to satisfy the effect of force control and position control in different directions at the same time. According to the above understanding, the thesis is divided into three parts: kinematics and dynamics model of manipulator and manipulator, pid force control based on virtual force sensor. Force tracking impedance control and force estimation collision avoidance control for two DOF series manipulator in different directions. Secondly, the following specific research contents are carried out in the three parts: the first part includes: forward and inverse kinematics and trajectory planning of two-degree-of-freedom series manipulator, kinematics constraints of simple hand grip, and so on. Kinematics-statics binary principle; dynamic model of linkage mechanism. The second part includes: the joint space open chain dynamics model of simple hand grip; the dynamic model of joint space closed chain based on the principle of kinematics and statics; the estimation of disturbance moment of driving joint; and the estimation of clamping force based on virtual displacement principle. The third part includes: dynamic model of manipulator, position control of inverse dynamics, impedance control of position inner loop, x axis force tracking impedance control and y axis force estimation and collision avoidance control. Finally, the simulation results of MATLAB Adams show that two kinds of problems have been solved in this paper: one is simple hand grip control based on virtual force sensor, and the other is the security, stability and cost of grasping task. The other is the combination of force tracking impedance control and force estimation collision avoidance control in different directions to solve the problem of compliance and safety of manipulator contact task systematically.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP241

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