Design And Investigation Of Open CNC System

With the continuous development of numerical control technology, the traditional numerical control system is not adapted to the tremendous changes and fierce competitions in the manufacturing industry which is developing towards the agile model and information integration model. New numerical control system, which is of stable performance, low cost and good openness, has been the hot research area all over the world.Comparing with foreign research, the structure and development tendency of open numerical control system was synthetically analyzed in this paper. Open source numerical control system EMC of the United States project OMAC was selected as the develop basis. EMC numerical control system consists of mission planning, motion control, I/O control and human-computer interface, four components. CNCAPI system was developed by using the NET technology based on EMC numerical control system. A cross-language COM structure was used to realize the core functionality of the CNCAPI system. Human- computer interface developed by C# language loaded CNCAPI system to realize the perfect combination of human-computer interaction and numerical control functions.This paper has developed a new type of tool radius compensation algorithm, which combines the advantage of B-type and C-type tool radius compensation algorithm. In this algorithm, processing block is presented by using the math idea of vector and the connection algorithm is determined by the angle between the blocks and motion types.The interpolation algorithm developed in this paper is based on the idea of Time-Slicing, which is divided into two parts:rough interpolation and fine interpolation. Higher-order speed control algorithm is used to complete acceleration and deceleration control when a sudden change of speed occurs, which prevents machine tool from vibration during working. In the stage of fine interpolation, rough interpolation points are fitted to calculate fine interpolation by using Cubic Spline. Fine interpolation points are outputted to the position control part, realizing accurate track control of machine tool.The interpolation algorithm and the tool radius compensation algorithm developed in this paper have improved the function and efficiency of the system, which meet the development of modern numerical control system toward high speed and accuracy.