并联驱动机械腿运动学静力学性能评价及几何参数设计  

Kinematic/static performance evaluation and geometric parameter design of parallel-driving leg mechanism

作　　者：张金柱[1] 金振林[1] 张天浩 

机构地区：[1]燕山大学机械工程学院,秦皇岛066004

出　　处：《农业工程学报》2017年第21期61-69,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家重点基础研究发展计划(973计划)资助项目(2013CB035501);机械系统与振动国家重点实验室课题资助项目(MSV201506);河北省研究生创新资助项目(2016SJBS011)

摘　　要：为了拓展农业机器人的作业场合,该文对一种三自由度六足腿式机器人并联驱动机械腿机构进行了运动学静力学性能评价及几何参数优选。首先,求解了足端线速度和角速度之间的耦合关联矩阵,定义了该腿部机构的运动学性能评价指标,绘制了该指标的分布图。其次,建立了腿部机构驱动静力学模型,分别利用机械腿在重力方向的最大承载力和驱动关节的最大扭矩定义了该腿部机构在软、硬地面下的驱动静力学性能评价指标。基于线性空间理论求解了驱动机构的约束雅克比矩阵,定义了约束静力学性能评价指标,通过绘制驱动与约束静力学性能评价指标分布图揭示了该腿部机构静力学性能在工作空间内的变化规律。再次,结合各项运动学和静力学性能评价指标,利用搜索法对该腿部机构几何参数进行了多目标优选,并给出了一组较好的几何参数。优选结果表明:平行四边形铰链长连杆及连接连杆的几何参数分别为330 mm和140 mm,地面接触连杆几何参数为320 mm时,腿部机构的综合性能得到改善,具体表现为运动性能提升了5.46%,重力方向最大承载力提升了18.02%,驱动关节的最大扭矩减小了6.33%。该研究结果可为该六足机器人步态规划及控制和应用提供参考。In order to raise mechanization and automation level of agricultural operations, broaden the scope of application of agricultural robot, a novel three degree of freedom leg mechanism used in the six-legged walking robot was introduced. The kinematic and static performances of the leg mechanism were analyzed. The geometric parameters of the leg mechanism were optimized by multiple objectives. In this paper, firstly, the coupling relationship between the linear velocity and angular velocity of the foot was resolved. The kinematic performance index was defined based on the condition number of Jacobian matrix. The distribution diagram of kinematic performance index was drawn. It can be seen that kinematic performance index was small in the central area of workspace of the leg mechanism from this distribution diagram. It was shown that the kinematic performance of leg mechanism was better in the central area than other areas of workspace of the leg mechanism. Secondly, the ground surface types were summarized as hard and soft ground surfaces considering the acting generalized force types between the standing foot and the ground surface. The acting generalized forces were three-dimensional pure force when the ground surface type was hard ground. The acting generalized forces were six-dimensional force when the ground surface type was soft ground. The driving static model of the whole leg mechanism was built based on the principle of virtual work. Then according to different ground surface, the local and global static performance evaluation indices were proposed. The distribution diagrams of the local static performance evaluation indices were drawn, respectively. It can be seen that the load performance was batter in the area of y＞0 than the one in the area of y＜0 （as shown in Fig.1）. Again the closer to the boundary of workspace the leg was, the better the static transfer performance of the leg mechanism was. But, the leg mechanism needed more rough ground to provide enough friction when the standing leg was i

关 键 词：机器人 运动学 静力学分析 并联驱动腿 性能评价 参数设计 

分 类 号：TP242[自动化与计算机技术—检测技术与自动化装置]