考虑传动间隙的工业机器人关节刚度辨识方法

Joint stiffness identification method of industrial robot considering transmission clearance

针对工业机器人刚度辨识成本高、辨识精度提升难的问题,提出一种基于千分表并且考虑传动间隙影响的关节刚度辨识方法.首先,建立机器人运动学模型和刚度模型,对传统刚度模型进行了改进,考虑了辨识过程中传动间隙对辨识精度的影响;其次,推导了仪器精度、测量量级、辨识精度之间的关系,在此关系式的基础上确定了以千分表为测量设备的接触式测量方案;最后,根据新方法开展了IRB6700-200/2.60型工业机器人关节刚度辨识实验.实验结果表明:使用千分表进行实验且不考虑传动间隙影响的预测相对误差为17.77%,与使用激光跟踪仪的预测相对误差16.80%相当,而考虑传动间隙影响的预测相对误差为11.00%,相比两者有明显提升.

Aiming at the problems of high cost and difficult to improve the identification accuracy of industrial robot stiffness identification,a joint stiffness identification method based on dial indicator and considering the influence of transmission clearance was proposed.Firstly,the kinematics model and stiffness model of the robot were established,the traditional stiffness model was improved,and the influence of transmission clearance on the identification accuracy was considered.Secondly,the relationship among instrument accuracy,measurement magnitude and identification accuracy was deduced.Based on this relationship,the contact measurement scheme with dial indicator as measurement equipment was determined.Finally,according to the new method,the joint stiffness identification experiment of IRB6700-200/2.60 industrial robot was carried out.The experimental results show that the relative error of prediction using dial indicator without considering the influence of transmission gap is 17.77%,which is equivalent to 16.80%using laser tracker,while the relative error of prediction considering the influence of transmission gap is 11.00%.