Error Modeling, Measurement And Real-time Compensation Of A 10 Meters Heavy Duty CNC Vertical Lathe

In this dissertation, the study focuses on a 10 meters heavy duty CNC vertical lathe. As the main finishing equipment in mechanical factory of GE CRC, this machine tool exists two main error sources greatly impact the machining accuracy: integrated tilt coursed by ram and beam, the table lift. Based on the systematic and scientific theories, an online software measurement system is explored, a new error modeling method is put forward, and the corresponding compensation solutions and methods are proposed. The content of this dissertation include the followings:1. The thesis firstly introduces the main parts of error compensation, and makes a review of the research history and present status of the error compensation, modeling and measuring. Finally, the main research procedures and contents are determined as: machine tool error synthesis modeling, error measurement, thermal error modeling and analysis.2. Analyze the main kinematical structure of machine tool and describe its topological structure by multi-body system kinematics theory. In addition, set the coordinate system and each error element, and then establish error synthesis model contained the geometric and thermal errors, so the theory basis for implementing machine tools error compensation and building monitoring platform is provided.3. According to the concrete structure and stress between the ram and beam, analyze the reason of the integrated tilt and develop an online precision measurement system which could be able to effectively overcome the on-site interference. Meanwhile, analyze the reason of the chuck-table rise and a temperature data acquisition system is established. By the way, the on-site test status is introduced so that the accuracy and stability of the system is verified.4. Put forward a new thermal error modeling method based on combining of the ridge regression and RBF network to solve the temperature variable co-linearity problem. Compared by radial basis neural network modeling method, the advantage of the optimization model is proved.5. Based on the analysis of external coordinate excursion function and the implementation of the strategy, error compensation control system of CNC vertical lathe is given, and then Effectively improve the processing precision.