Research On The Key Technology Of Anti-Collision System Of Numerical Control Equipment

NC(Numerical Control)machining and measuring equipment has been widely used in advanced manufacturing technology and scientific research,especially in the automotive industry,machinery manufacturing industry,aerospace industry and other important areas.Its application is more and more extensive.With the "Made in China 2025" being proposed,NC machining and measurement need to be more intelligent and automated,to avoid collision accidents,intelligent selection of appropriate machining or measurement path.In this paper,the coordinate measuring machine as the numerical control equipment platform is for key technology research of anti-collision system.But related technology can be applied to other similar numerical control equipment,not limited to the coordinate measuring machine.Traditional coordinate measuring machine testing requires manual operation,which requires a lot of manpower costs,and manual operation detection efficiency is relatively low,a large number of repetitive monotonous works will make people because of fatigue and operation error.So to improve the anti-collision capability of NC equipment system has become an urgent problem to be solved.In order to improve the anti-collision ability of the coordinate measuring machine and realize the intelligent detection,the main contents are as follows:1.The anti-collision system of NC equipment is studied.Based on the actual and virtual two spaces anti-collision system is realized.The operation to be performed in the actual space is simulated in the virtual space,safe operations are planned,and finally which are sent to the actual space to perform.2.For the conventional mechanical parts,a method of identifying the position and orientation is proposed,and a new visual system is designed.The position and orientation of conventional workpiece is recognized by the characteristics of the round hole,corner point and straight line segment.For the free-form surface workpiece,this paper proposes a position and orientation recognition method based on T-spline unified model.Firstly,the surface point cloud of the free surface workpiece is sampled according to the designed visual system,and then the point cloud of the design model is generated according to the T-spline surface of the workpiece.Finally,the position and orientation of the workpiece is determined by the point cloud registration.The overall error of recognizing the position and orientation are less than 1mm.3.For the application of large or multiple mechanical parts,a local path planning method based on improved ant colony algorithm is proposed.The improved ant colony algorithm combined with the artificial potential field increases the repulsive force between the moving equipment and the obstacle and the gravitational force between the moving equipment and the target point.It improves the ability to find the optimal path of ant colony algorithm at a good convergence rate,to avoid the occurrence of a collision accident.The number of algorithm iterations reduce from 80-90 to 20-30.4.For the larger workpiece,an overall path planning method based on the improved ant colony algorithm with the shortest time is proposed.At the same time,a ball model for calculating the azimuth of the probe is proposed.The overall path planning method can better find the shortest consuming-time detection path.The ball model can intelligently calculate the contact orientation of the probe when the hiding point is detected.