重载工业夹持器约束建模与承载能力分析

Constraints modeling and loading capacity analysis of heavy-duty industrial grippers

针对重型工件的抓取操作问题,采用机器人抓取理论建立工件-夹持器系统的抓取模型,分析抓取模型求解中存在的静不定问题;基于准刚体模型,建立工件微分运动与接触变形之间的映射关系;分析夹持器在不同驱动形式和夹持过程中的约束特点,建立夹持器驱动关节和被动关节的力约束方程;引入关节刚度和接触刚度,建立工件-夹持器系统能量模型;采用拉格朗日乘子法建立静不定抓取力分析求解模型,给出了具有运动形式简单、约束复杂特点的一类夹持器的承载能力分析方法.以80t锻造操作机夹持器为实例进行了承载能力分析,仿真结果与实验结果相符合,验证了抓取力分析模型的正确性.

Workpiece-gripper system model was proposed for the heavy-duty manipulation using grasp robot grasp theory.From the workpiece-gripper model,the grasp forces are indeterminate.To solve indeterminate grasp force,a quasi-rigid body model was adopted to describe the relationship between the differential motion of work-piece and contact deformation.Based on the analysis of special constraints with different driven modes and grasping states,the force constraints equations were proposed for the driven joints and passive joints of gripper respectively.A potential energy model was proposed for workpiece-gripper system with the assumed joint stiffness and contact stiffness.Based on the Lagrange multiplier method,a computing method was proposed to solve the indeterminate grasp force heavy-duty gripper with simple motion but complex constraint.As an example,loading capacity analysis of 80 tons forging manipulator was carried out.Simulated and experimental results are in good agreement,which verify the correctness of the grasp analysis model.