Dynamic Modeling And Performance Analysis Of Work-Bench Of Driven At Center Of Gravity

The technology of NC machining of high speed and high precision plays a very important role in the field of machining. And the feed drive of high speed is one of the key technologies to realize high speed and high precision machining. Driven at Center of Gravity (DCG) is an innovative feed drive method for machine tool, and it can increase the motion velocity and accuracy of machine tool effectively but the research on it is still in an infancy stage. In this paper, a two- axis work-bench of DCG is studied, and the parametric model of the DCG is established, the finite element method is utilized to analyze the dynamic characteristic of the work-bench. Moreover, the mechatronic integrated simulation is performed on the work-bench. Finally, the dynamic performance of the whole feed drive system is evaluated and the parameters are tuned. Specific contents include as follows:(1) The dynamic principles of DCG are analyzed and the vibration equations are acquired. The finite element modeling method of the DCG work-bench is established. Based on the dynamic equation and the finite element matrices, the vibration equations of the finite element of the DCG. work-bench are deduced, then the expression of response characteristic is further obtained.(2) By analyzing the influencing factors of dynamic characteristic of DCG feed drive system, these influencing factors are parameterized and the parametric model of work-bench of DCG is established. The mode analysis of different parameters is performed, then the relation between dynamic characteristic of the feed drive system and the structural parameters is proposed by comparison of their natural frequencies and mode shapes. The ANSYS software is utilized to perform the harmonic analysis on the model of the work-bench of DCG, thus the resonance vibration frequency and vibration characteristic of the work-bench have been gotten.(3) Based on the mechatronic integrated system simulation method, dynamic characteristic of traditional work-bench and work-bench of DCG are simulated separately. The results show that feed drive of DCG is not notably superior to traditional feed drive method when the accelerate value is not high, while in high accelerate, the dynamic characteristic of feed drive of DCG is much better than traditional feed drive system. Vibration can be restrained effectively on the work-bench of DCG, the motion accuracy is much higher than traditional feed drive method especially in the corner of the profile. (4) Dynamic performance of feed drive system of DCG is evaluated using performance criteria, and the servo parameters are tuned to optimization according to the performance criteria. The results of simulation indicate that the dynamic performance of the machine axes can be greatly improved and the bandwidth of the servo control system is much higher after the servo parameters are tuned.According to the research above, a feasible method is proposed for structure optimum design, wide bandwidth servo control and dynamic performance optimization of work-bench of DCG.