The Movement Error Compensation Strategy Research And Its Experiment Verification Of The Metamorphic Cutting Machine

In the manufacturing process of ship,cutting holes which is of large diameter intersects on complex-surface is a key technology and an important factor which restrict China’s modernization of shipbuilding.Traditional processing step,such as artificial loft,manual cutting and post polishing,cannot meet the requirements of shipbuilding,not only for the reason of cumbersome,but also low precision.Therefore,a better way to solve these problems is of great significance to improve China’s shipbuilding quality,and to shorten the gap between the advanced worlds level.After studying a great numbers of researches of related advanced process technologies at home and abroad,and under the require of specific design,the structure scheme of a five degrees freedom flame cutting machine based on the metamorphic principle was proposed in this paper.Then,the works of mechanical structure,transmission type,system’s control scheme were finished,and the problem of big openings,variable posture and changing track in large complex-surface cutting is solved.At the same time,master-slave synchronization control technology was taken to solve this problem of collaborative movement between multiple freedoms after analyzing the load conditions of each freedom and the characteristics of different synchronous control technique.At last,the validity of the master-slave synchronization control in improvement of the synchronization accuracy was verified,with the complement of comparative analysis of the synchronization control error based on the end closed-loop agency of the machine.For some mathematical problem of the cutting process based on the structure and control system of the metamorphic cutting machine,mathematical analysis of the cutting path,cutting thickness,motion between freedoms and the motion regular pattern between active structural components was completed.Meanwhile,in order to make it easier in error modeling,the cutting machine’s configuration in five different states were analyzed,and we consolidated the five different states into three basic configurations: straight cutting configuration,beveling configuration and attitude change configuration.With the analysis of the structure error and drive chain error sources of the cutting machine,modeling work of the structure error at three configurations were finished,and at the same time,the model is under screw theory and the minor joint space errors were ignored.Finally,the simulation analysis of the structure error at straight,downhill and uphill cut with MATLAB was completed,and the structure error’s theoretical value of the cutting machine was obtained.Considering the problem of multiple correlations between variables and small sample size exist among the Least-Squares,the structure error was compensated by using Partial Least-Squares method based on the structure error model of the metamorphic cutting machine and the feed forward error compensation method,The derivation of the posture error model was completed after brief introduction of Partial Least-Squares method,then got the error compensation flowchart and designed the error compensation algorithm based on Partial Least-Squares method.Finally taking the downhill cut as an example,the simulation analysis of the error compensation effect with MATLAB was completed,and the results show the effectiveness of the compensation method.With the use of the XPC Rapid Control Prototyping method,we design the software and hardware of the metamorphic cutting prototype.After the running test,the correctness of the cutting machine’s principle was verified and a theoretical reference for the manufacture of the actual cutting machine was provided.