The Research Of The Chatter Analysis And Vibration Suppression Strategies In Deep Hole Drilling

In the process of deep hole drilling, generally there are three forms of vibration: freevibration and forced vibration and self-excited vibration. By eliminating the externalexcitation source, or other methods can suppress or even eliminate the free vibration andforced vibration, but it is hard to find an effective method to suppress the self-excitedvibration (chatter) generation. Chatter will not only reduce production efficiency and reducethe life of the tool and machine, but also endanger the health of the operator. So the study ofthe chatter have some practical significance.MR fluid is a new intelligent material, which can magnetorheological effect occurs underthe applied magnetic field, in milliseconds between the solid-liquid two-state transformation.In an additional magnetic field, its viscosity, yield stress and shear modulus dramaticallyincreases in the millisecond units. After the magnetic field disappears, the MR fluid can berestored to its original state instantaneously. So MRF has good application prospect invibration control.For the chatter problem in deep hole drilling, we propose to suppress the chatter by usingthe MRF. Firstly, analyzing the chatter generated mechanism in metal cutting process, theregenerative chatter is proved to be the the most important mechanism of self-excitedvibrations and analyzed the regenerative chatter and coupling chatter in drilling process. Bystudying their dynamic model of deep hole drilling process to identify their respective criticalcondition.Secondly, studying the principle of MR fluid material, the mechanism of MRF effect andthe design principle of MRF damper, we design a MRF damper used in the deep hole machine,and get the dynamic model and dynamic equation. And then, simulated the dynamic equationby Simulink components of Matlab, the result shows that the MRF damper has goodsuppression to chatter. Finally, a damping control algorithm based on BP neural network PID is designed tomake a better control of the vibration of the deep hole drilling using MR damper. Thisalgorithm, taking advantage of the on-line study ability of BP neural network, can adjust andoptimize the parameters of PID constantly, which makes the vibration control of the deep holedrilling and MR damper system have very strong self-adaptive capacity and robustness.