码垛机器人运动学分析和控制系统设计

Kinematics analysis and control system design of palletizing robot

针对一类关节坐标四自由度码垛机器人,对其机械传动结构进行分析,构建其运动学坐标体系;根据码垛生产特点,运动路径规划采用设定点位法,其中一些点位的脉冲坐标通过示教法直接确定,其余点位脉冲坐标则通过正、反运动学求解获取;为降低运动学求解复杂程度,将三维空间坐标体系的求解,先分解到两个平面坐标中单独进行,然后再加以合成;控制系统以PLC为核心,各轴驱动采用高精度交流伺服系统,通过原点回归确定各轴原点,根据目标点位实时计算各轴运动脉冲数和频率,采用绝对定位驱动方式实现机器人各轴联动;实际运行效果表明,运动学求解复杂程度的降低,提高了系统运算速度和实时性,而绝对定位方式可避免相对方式下的累积误差,从而提高了系统的运动精度。

This paper introduces the mechanical structure and control system of a kind of four DOF palletizing robot. The point-setting method is used for trajectory planning, that some points are determined through teaching method directly, the remaining points are obtained by the forward and reverse kinematics solving. PLC is used as controller in this system, each axis is driven by AC servo system, and the origin of each axis is determined by return-to-zero-point instruction. According to the target point coordinate, the driving pulse numbers and frequency of each axis are calculated in real time, the linkage of all axises is realized by the absolute positioning method, which avoids the accumulated error and improves the accuracy of motion, compared with the relative positioning method.