Dynamic Analysis Of Ball Screw Pair For Servo Mechanism And Research On Motion Failure Mechanism

The ball screw used in servo mechanism is faced with high-speed,high-frequency and overload conditions.Under this special condition,the traditional design method and analysis theory of the ball screw are no longer applicable.At the same time,due to the non maintainability of the ball screw used in aerospace,the occurrence of its motion failure will lead to the paralysis of the whole servo mechanism.Therefore,it is necessary to study the dynamic analysis and motion failure of ball screw under special working conditions.In this paper,the elastic-plastic contact model of the ball screw pair under the condition of static uniform load was established and an example was calculated.The initial yield axial load of the ball screw pair under the condition of deformation coordination was derived by genetic algorithm(GA),and the maximum static contact force of the ball under different working conditions was calculated according to the load distribution model.Then,the dynamic model of the ball in the raceway was established under the conditions of contact deformation,lubrication resistance and centrifugal force.Then,the generating conditions of the wedge effect of the ball in the raceway plane are deduced,and the change trend of contact parameters,friction coefficient and angular velocity under different working conditions is analyzed by using MATLAB software.The movement and force of the ball passing through the reverser are analyzed,and the thrust formula of the ball at different positions of the reverser is obtained.The factors that affect the thrust and the causes of the ball jamming when passing through the reverser are analyzed by combining the ADAMS simulation results.The applicable conditions of the matrix reverser are analyzed by comparing the simulation results of different reversers.Finally,a high-frequency inertial loading test-bed is designed based on PXI bus and the dynamic test of the ball screw with matrix reverser is carried out.Through the comparative analysis of the measured input torque characteristics and simulation results under different working conditions,the reason for the sudden change of the input torque is obtained,which provides the direction for the research of the jam motion failure of the ball screw.