Vibration Suppression Of Cutting Tool System In Deep Hole Process By Using Independence Mode Space Control

High-precision,low-cost,and environmentally-friendly deep-hole drilling technology is an urgent need in Chinese rapidly developing new energy,military,and other key areas.Due to the complexity of the deep hole drilling technology,how to achieve precise control of the dynamic characteristics of the tool system under the premise of guaranteeing that the deep hole drilling system is not destabilized,and then processing the ideal quality of the deep hole work pieces has become the hottest research in this field.Considering the direct correlation between the roundness error of hole and vibration mode of cutting tool in deep hole machining,a novel control strategy was proposed for suppressing vibration of tool system based on independence mode characteristics.On the basis of Timoshenko finite element model,the independence state control equations of drilling tool system which included the vibration suppressing damper with variable stiffness or damping were established via modes reducing and decoupling,so that a series of physical space information of tool dynamic model can be transferred into modes state space to overcome the problems of excessive control parameters and intercoupling effect arising in traditional physical space.With the target of real-time suppressing vibration,optimal mode performance indexes were fixed as the object of destroying or suppressing modes.At the same time,mode displacement and mode acceleration in Luenberger state observer were introduced into feedback gain matrix modified by generalised pole assignment method,and consequently,"precision-strike" mode force needed by physical space can be obtained against the object of vibrating mode.Finally,a series of experimental investigations are carried out to confirm the feasible and effectiveness of the independence mode state equations of drilling tool system,and simultaneously,roundness errors of hole were calculated numerically under the different magnitude conditions of mode force.Whether experimental or computation results indicate that this method proposed in this paper will be able to be a possibility of targeted suppressing the tool vibration and controlling hole roundness error actively in deep hole drilling process.