A Way To Position Probe At Six-DOF For Detecting Surface Texture Of Ruled Surface

With the constantly development of advanced manufacturing area,higher requirements of the part quality are put forward.Actually,the part quality can be characterized as surface texture,so measuring the surface texture accurately and effectively is an important premise to develop advanced manufacturing equipment.For most parts,the needs of measuring its surface texture can be met by usual detection technology.But for complex ruled surface parts,such as blade,aerosol and impeller,which are important parts in manufacturing area,there are limitations while measuring these parts,such as not enough space,difficult positioning and so on.To solve these problems,a Six-DOF positioning system for detecting surface texture of ruled surface is proposed in this paper.And a series of efforts on the positioning of the probe at Six-DOF has been carried out in this paper.The main work of this paper is as follows:1.Based on the standard surface texture detection,the surface texture detection of ruled surface is proposed according to its profile features and side milling processing mechanism.To solve the probe positioning problem with usual detector,a Six-DOF positioning system which is used to fix transverse scanning probe for detecting the surface texture of ruled surface is proposed.And considering that there is angular deviation of the probe actual positioning orientation caused by system error,the influence of the angular deviation on detection result is analyzed2.According to the demand of positioning probe at Six-DOF,a method to position the point to be detected with human-model interaction is proposed based on the method of positioning the point through the parametric equation of the ruled surface,by establishing the correspondence between the(u,v)coordinate of the parametric equation and the UV texture coordinate using OpenGL 3D modeling technique.Through this method,the point to be detected on the ruled surface can be visually positioned,and its position and orientation coordinate can be obtained,but the point cannot be specified by user accurately.To solve this problem,a method to position the point to be detected by inputting its coordinate manually is proposed based on the first method.To realize the two methods,the algorithms of reading the model file,interactive displaying the model,picking triangular piece and picking point with ray/triangle intersection and so on are designed.3.The positioning process of the probe is designed based on the motion control mode of the positioning system to realize the probe positioning at Six-DOF.To determine the displacement of the probe from starting point to the point to be detected,the kinematic model of this system is built based on the multi-body system theory,and the inverse kinematics of this system is analyzed according to the kinematic model.The machine coordinate origin and the workpiece coordinate origin are determined by using the mark and 3D touch point sensor respectively.4.A control software is developed by VS 2010 equipped with the OpenGL port and the dynamic link library of motion control card,to realize the positioning of point to be detected on the ruled surface and the positioning detection of the probe.And the functions of the software are tested by black box test method.Then,through the control software,the specified point repeated detection experiment and the homing repeated detection experiment are carried out to verify the specified point detection accuracy of the Six-DOF positioning system.