曲轴连杆颈圆度在线测量机构设计与运动分析

Design of roundness online measuring mechanism for crankshaft connecting rod neck and analysis on its kinematics

曲轴随动磨削时,连杆颈的偏心旋转运动导致其中心位置不断变化,使得常规方法无法直接用于目标连杆颈圆度测量。为解决这一难题,文中提出了一种采用机械臂与V形测量机构相结合的设计方案,将V形块作为机械臂末端执行器,通过控制机械臂改变测量机构位置,抵消因连杆颈偏心转动导致的位置变化,实现连杆颈的圆度在线测量。基于D-H法,对所设计的曲轴连杆颈圆度在线测量机构的正逆运动方程进行了推导与分析,并通过Simulink软件验证推导运动方程的正确性。最后,采用图形法分析了机构工作空间,结果表明:所设计的机构完全满足使用要求。

When the crankshaft is subject to follower grinding,its center position changes constantly because of the eccentric rotational motion of the connecting rod neck;as a result,the conventional method can’t be used directly for roundness measurement of the connecting rod neck.In this article,in order to solve this problem,a scheme which combines a manipulator arm and a V-shaped measuring mechanism is proposed.The V-shaped block is used as the manipulator arm’s end actuator;the manipulator arm is controlled to change the measuring mechanism’s position,and the change in the position caused by the eccentric rotation of the connecting rod neck is offset;thus,the connecting rod neck is subject to online measurement.Then,with the help of the D-H method,the forward-and-inverse motion equations of the roundness online measuring mechanism for the crankshaft connecting rod neck are derived.Simulink is used to verify that the motion equations are correct.Finally,the analysis is conducted on the mechanism’s working space by means of the graphical method.The results show that this mechanism fully meets the requirements of utilization.