一种机器人球腕的模型优化方法

Optimization method for model of robot sphere-wrist

许多机器人的共同特点是在操作臂末端安装了球腕.球腕是机器人上一个重要的独立结构,它的静态误差必然影响操作臂末端执行器的位姿精度.以机器人末端的球腕作为独立的研究对象,在静态误差分析的基础上,提出了一个评价球腕精度的综合指标.根据这一指标建立优化模型,对存在静态误差的球腕模型进行优化,从而建立新的球腕运动学模型.应用新模型进行运动学及动力学解算,可以减小机器人球腕的位姿误差,特别是减小具有较大静态误差的机器人球腕的位姿误差.通过对机器人球腕进行的局部优化,整个机器人末端执行器的运动精度将在一定程度上有所提高.

The installation of a sphere-wrist at the end of the manipulator is a common characteristic of many robots. The sphere-wrist can be regarded as an important independent structure of a manipulator. Static errors of sphere-wrist will affect the pose precision of the end effector. Taking sphere-wrist as study object, a comprehensive criterion to evaluate its precision was presented on the basis of the analysis of static errors. Using this criterion, an optimization model was constructed to rebuild the model of the sphere-wrist that had static errors, and hence a new kinematic model of the sphere-wrist was constructed. When this new model was used in the kinematic and dynamic computing, the pose error of the sphere-wrist could be reduced evidently. This optimization method will be more beneficial to a sphere-wrist with big static errors. By the partial optimization to the robot with a sphere-wrist, the kinematic accuracy of the end effector of the whole robot can be increased to some extent.