五轴并联机床刀具末端运动位姿自适应控制技术

高精尖领域对精密小零件的加工精度要求越来越高，五轴并联机床作为主要机械加工设备，严格控制机床刀具的运动位姿对于保证成品零件的加工精度具有极其重要的作用。在此背景下，研究一种五轴并联机床刀具末端运动位姿自适应控制技术。在五轴并联机床前方布置两个CCD 摄像头作为视觉系统，拍摄关于刀具末端的左右两张图像；在图像预处理、特征点提取与匹配等环节的基础上，求解位姿参数，包括位置三维坐标以及3个姿态数据。以刀具末端运动实际位姿为输入，利用神经网络获取与刀具末端紧密相连的五轴关节角度补偿量。利用PID控制器，通过补偿量计算位姿控制量不断纠正位姿误差，靠近理想位姿。结果表明：应用所提控制方法，与理想位姿之间的平均误差均更小，且平均误差的波动最小，三维位置坐标波动仅在-0.02~0.015、-0.01~0.02、-0.02~0.02 mm之间；横滚角、俯仰角以及方位角波动仅在-0.02°~0.03°、-0.01°~0.04°、-0.02°~0.01°之间，由此说明所提控制方法的精度更高，控制稳定性更高。

Adaptive Control Technology of Tool End Motion Pose of Five Axis Parallel Machine Tool

In advanced field,the requirements for machining accuracy of precision small parts are getting higher and higher.As main machining equipment,five axis parallel machine tool plays an extremely important role in ensuring the machining accuracy of finished parts by strictly controlling the motion posture of the tool on the machine tool.A five axis parallel machine tool end motion pose adaptive control technology was studied.Two CCD cameras were arranged in front of the five axis parallel machine tool as the vision system to capture the left and right images of the tool end.On the basis of image preprocessing,feature points extraction and matching,the pose parameters,including 3D coordinates and three pose data,were solved.Taking the actual pose of the tool end motion as the input,the five axis joint angle compensation closely connected with the tool end was obtained by using neural network.Using the PID controller,the position and attitude control quantity was calculated through the compensation quantity,and the position and attitude errors were continuously corrected,closing to the ideal position and attitude.The results show that applying the proposed control method,the average error of the ideal pose is smaller,and the fluctuation of the average error is the smallest,and the fluctuations of the 3D position coordinates are only from -0.02 mm to 0.015 mm,-0.01 mm to 0.02 mm,-0.02 mm to 0.02 mm;the rolling angle,pitch angle and azimuth angle fluctuate only between -0.02° and 0.03°,-0.01° and 0.04°,-0.02° and 0.01°,which show that the proposed control method has higher accuracy and control stability.