Research On Roll Angle Measurement Technology

With the continuous improvement of modern industrial processing accuracy,higher requirements have been put forward for industrial measurement technology.CMM(Coordinate Measuring Machine)is widely used due to its good flexibility and high accuracy.However,most CMM is contact measurement,with low measurement efficiency and easy to scratch the surface of parts,resulting in limited application.This thesis did research on measurement control technology based on a special three coordinate non-contact measurement system.The system used a high-precision turntable to drive the workpiece to rotate,and used photoelectric probe data and three coordinate data to calculate and obtain the radial dimensions of rotary parts.The probe motion path control planning is an important research to improve measurement efficiency and accuracy.Based on the analysis of the composition and working principle of the noncontact CMM system,this thesis investigated the motion control path planning and simulation of the system during the measurement process using ant colony algorithm.The thesis has accomplishes the following specific research.(1)Analyze the hardware composition and measurement principle of the system,establish the coordinate system,and construct the mathematical model according to the relative position relationship of the moving parts of the system,transform the three coordinate straight axis data,the turntable angle data and the laser probe data into the coordinates under the corresponding coordinate system for compound calculation,analyze the influence of the motion path control on the acquisition data during the acquisition process,and construct a three-layer structure motion control planning framework for system measurement.(2)Study the method of generating coordinate points of the part model,develop a sampling strategy,and establish the foundation for control path planning.Analyze the IGES(Initial Graphics Exchange Specification)file specification and its data format,obtain the recording methods and recording rules of IGES files for different features such as plane,cylindrical surface and free-form surface,and study the solutions for data loss,surface loss and surface judgment problems in data conversion,establish a sampling model to extract sampling points for the known model under test,and form the sampling strategy.(3)Study the motion control path model combining the raster map method and the Cartesian coordinate system method,and use the ant colony algorithm to plan the motion control path in the system measurement process.Analyze the basic principle and characteristics of ant colony algorithm.And use the control variable method to optimize and set the heuristic factor,expectation factor,pheromone residue coefficient,ant number,total pheromone,and other parameters in the ant colony algorithm,ultimately obtaining an ideal path.(4)Construct a typical geometric model of the measured part,generate sampling points,and use the ant colony algorithm to conduct simulation experiments on different rotary parts to verify the effectiveness and feasibility of the algorithm.The simulation experiments show that compared with the manual planning,the ant colony algorithm applied in this thesis is more adaptable to the measurement of different parts,shorter motion control paths,fewer round trips of the probe during movement,and a 30% improvement in measurement efficiency.the control path obtained by the ant colony algorithm is applied to measure the standard sample column,and the experimental results show that the accuracy is improved by 3μm compared with the manual planning path.