摘要
近年来,以工业机器人为执行体的机器人磨抛由于其灵活性好、通用性强等特点正逐渐成为复杂曲面磨抛的发展趋势。在机器人磨抛加工过程中,刀具路径点常以曲面上曲率及法线方向为导向进行划分,但尚未考虑机器人实际运动姿态变化对磨抛路径光滑性产生的影响,且可能存在工件与工具干涉问题,因此难以保障最终加工精度。为此,提出了以磨抛姿态变化为约束并光顺干涉处姿态的规划方法。首先,以机器人末端磨抛姿态变化作为刀位点划分阈值,综合考虑其他非法线方向的位姿变换,减缓了刀具路径点之间的姿态变化。然后,在干涉处改变刀具姿态,并以等参数圆进行范围性光顺从而解决干涉问题。最后,综合姿态变化约束和干涉刀位点的姿态光顺,规划出一条光滑无碰撞的机器人磨抛路径。利用机器人砂带磨抛系统对航空发动机叶片进行磨抛试验,结果表明,所提规划方法的关节角速度变化平缓,刀具路径光滑性更好,磨抛后叶片轮廓度满足−0.03~+0.05 mm公差带要求,表面粗糙度由Ra>3.2μm提升至0.2472μm,验证了所提规划方法的有效性。
In recent years,robotic grinding with industrial robots as the executive body is gradually becoming the development trend of complex curved surface grinding due to its flexibility and versatility.In the process of robotic grinding,according to the curvature and normal direction on the surface,the tool path points are usually divided.However,the influence of the actual movement posture of the robot on the smoothness of the grinding path is not considered,and there may be interference between workpiece and tools.Therefore,it is difficult to guarantee the final machining accuracy.Therefore,a planning method that takes the change of the polishing posture as a constraint and smoothes the posture of the interference is proposed.Firstly,the robot's posture change are used as the threshold for dividing the tool position points,and the posture changes in other illegal line directions are considered,which slows down the posture changes.Then,interference problem is solved by changing posture at the interference point,and perform range smoothing with isoparametric circles.Finally,the posture change constraint and the posture smoothing of the interference tools are combined to plan a smooth and collision-free robot grinding and polishing path.The robotic abrasive belt grinding system is used to grinding experiments on aero-engine blades.The results show that the proposed method has smooth changes in joint angular velocity and better tool path smoothness.The contour of the blade after grinding meet−0.03~+0.05 mm tolerance zone,the surface roughness increases from Ra>3.2μm to 0.2472μm.The effectiveness of the proposed planning method is verified.
作者
罗来臻
赵欢
王辉
李祥飞
丁汉
UO Laizhen;ZHAO Huan;WANG Hui;LI Xiangfei;DING Han(State Key Laboratory of Digital Manufacturing Equipment and Technology,Huazhong University of Science and Technology,Wuhan 430074)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2022年第3期284-294,共11页
Journal of Mechanical Engineering
基金
国家自然科学基金(52188102,52090054)
湖北省自然科学基金(2020CFA077)资助项目。
关键词
机器人磨抛
刀具路径
姿态光顺
干涉
等参数圆
robotic grinding
tool path
smoothing posture
interference
isoparametric circle