Design Of Disc Cam Contour Following Measuring And Control System Based On Cylindrical Coordinate System

Disc cams are commonly used in various mechanical systems such as internal combustion engines,machine tools,and automated production lines,and play a crucial role in transmission systems.Complex motion control can be achieved through the geometric shape and contour curve design of cams,so the contour measurement design of such parts is very important.The existing cam profile measurement technology is usually based on a Coordinate Measure Machine in a Cartesian coordinate system.This project is derived from a horizontal project of an enterprise.By utilizing the high efficiency characteristics of a cylindrical coordinate measuring instrument,we will simulate the motion forms of the main and follower components of a straight moving disc cam mechanism with a centripetal push rod,We will study and design a relatively complete control system for this measuring instrument to obtain follower lift data and achieve follow-up measurement of the cam profile.Firstly,starting from the research object,the contour measurement technology was analyzed and studied with the background of coordinate measurement,and the idea of reverse measurement design based on cam contour was determined.From the point of view of "inversion method",the principle of polar coordinate follow-up measurement of cam plane profile is defined,i.e.actively driving probe to follow cam to simulate follower movement.Therefore,the overall idea of the measurement scheme of "PCI bus-based motion control combined with USB data acquisition" has been determined.Secondly,the specific construction of the measurement and control system revolves around the cylindrical coordinate system measurement instruments,including five subsystems:mechanical structure,motion control,data measurement,data acquisition,and upper computer software.Improve mechanical probe assembly,analysed the influence of speed control curve and AD acquisition mode on motion control and data acquisition,and the characteristics of other key components are analyzed.Using the upper computer software system as the human-computer interaction medium,control the coordination and cooperation of various subsystems to obtain key feedback data for follow-up measurement.Research and design relevant data processing methods to obtain closed and smooth contour curve,including pre-processing of outlier removal,spline interpolation filling and filtering smoothing;The cam lift curve is obtained through cubic spline interpolation,the radius of the base circle is obtained through least square fitting,and the two-dimensional contour of the cam is obtained through non-uniform B-spline curve interpolation.And further analyze and study the identification and adjustment methods of cam phase based on the lift curve.Finally,the upper computer monitoring and control software is developed using C#language and WPF framework,which achieves a satisfactory tracking measurement effect and integrates a data processing module programmed in MATLAB.Set up the measuring and control experimental bench,take eccentric circle and the small cams on camshaft as measuring objects to obtain the lift data of follower,and then fit the relevant contour curve,which verifies the feasibility and accuracy of measurement and control principles,solutions,and data processing methods.