ZHU Hong-tai1，YUN Chao1，ZHOU Wen-ming2

（1. School of Mechanical Engineering and Automation，Beihang University，Beijing 100191，China；

2. Muyang Co., Ltd., Yangzhou 225000，China）

Abstract：Aiming at designing a grinding robot，the workspace of which must meet with the size of the workpiece，a 3P3R structure was put forward. Robot’s workspace was determined by many factors such as the structure parameters and the relative positions of gringding robot and the belt grinder. The structure parameter calculation and dexterous were studied. First，the calculation about the 3P3R grinding manipulator was presented which was based on the twist theory.Simplified model of the workpiece to be machined and previous work based on the actual situation of the reference process was summarized，the concept of a virtual ball was proposed. The kinematic model was made. Second，the size of the grinding manipulator was determined by a given workpiece. The belt grinder's position with respect to the robot base was optimized，additionally，the detailed derivation of the formula and the optimization flow chart were presented. Meanwhile，the simulation about the dexterous grinding space was verified by Monte Carlo method，and a software implementation based

on Matlab platform was made. Finally，the result indicate that the backward calculation of the manipulator structural parameters and optimized algorithm is not only stable and practical，can also be referred in the structural design of other types of manipulators.

Key words：3P3R; grinding robot；kinematics analysis；structural parameters optimization