Study On Stiffness And Dynamic Characteristics Of C - Type Gantry Parallel Milling Machine

The stiffness and dynamic characteristics of parallel machine are the main factors affecting the machine accuracy and efficiency. Therefore in order to analyze the impacts of weak links which affect the machine performance, it is necessary to make study on the machine rigidity and dynamic performance. On this basis, it can provide a reference value for the optimization of the design of the machine. In this paper, based on 3-(2SPS) parallel mechanism, study the dynamic characteristics of the machine respectively from the machine stiffness and vibration characteristics.(1) In this paper, the motion analysis for the 3-(2SPS) parallel mechanism was made. It is mainly for the institution to calculate the inverse solution, calculate the Jacobian matrix; At the same time, the force analysis on branched-chain bridge was made. The force analysis of the single chain was made in its work space.(2) In this paper, it is mainly analysis the stiffness of the 3-(2SPS) parallel mechanism. firstly, analysis the stiffness of major component parts of single chain, established single branched stiffness model based on the series principle. Secondly, according to the first-order influence coefficient method combined with the principle of virtual work to establish parallel mechanism stiffness model. Combined with simulation software to analysis single chain stiffness variation with length variation of single chain. And at the same time analysis the stiffness of the parallel mechanism in its working space.(3) In this paper, it is mainly analysis the dynamic characteristic of the 3-(2SPS) parallel mechanism. The single chain vibration model based on multi-degree-of-freedom vibration theory was established. Based on this, translate it to single degree of freedom vibration model. The establishment of a mechanism vibration model combined single degree of freedom vibration model based on Alembert principle. Make simulation analysis on natural frequency of vibration of the machine. At the same time, analyzed the harmonic response under the exciting force, and then, some amplitude versus frequency curves within a certain frequency range is obtained. The frequency range is fined that machine tools should be avoided according to the simulation results.