Research On Dynamic Characteristics Of The Centrifugal Pendulum Vibration Absorber

Automobile powertrain is a complex and flexible system,the dynamic load caused by torsional vibration will affect the normal operation of powertrain and automobile ride comfort,but also accelerate parts wear and fatigue damage.Therefore,the torsional vibration control of automobile powertrain has been the research emphasis of automobile engineers.For traditional clutch driven plates,the damping spring is short and deformation is limited,so the damping effect is limited.For engine with few cylinders,the damping effect of dual mass flywheel is still limited.And limited by the high cost of production,dual mass flywheel is not universally accessible to economy vehicles.The invention of centrifugal pendulum vibration absorber provides a new solution for controlling the torsional vibration of powertrain.The centrifugal pendulum vibration absorber has good damping performance,which has been widely used in the field of aerospace.But it is seldom used in the automotive field.This thesis is based on the project of torsional vibration control of the CM3 C powertrain of front engine rear drive vehicle,which is cooperated by Automobile Engineering Research Institute of China Automotive Technology Research Center and a well-known domestic automobile enterprise.In this thesis,multi-purpose vehicle CM3 C is used as the research object,and the research on centrifugal pendulum vibration absorbers and torsional vibration control is carried out.Firstly,this thesis summarizes the research background and significance of the centrifugal pendulum vibration absorber and discusses the necessity of the study of the centrifugal pendulum vibration absorber.On the basis of analyzing and summarizing current research of the centrifugal pendulum vibration absorber and torsional vibration control of powertrain both at home and abroad,the main research content and technical route of the thesis are confirmed.Secondly,the structure of the centrifugal pendulum vibration absorber is discussed.The suitable generalized coordinate system is selected,and the general form of differential equation of the centrifugal pendulum vibration absorber is deduced by using Lagrange equation.Subsequently,the differential equations of motion under the circular trajectory are deduced.Its natural frequency expression is derived,and the mechanism of vibration reduction is analyzed.Thirdly,the basic theory of torsional vibration,the establishment of torsional vibration equivalent model of powertrain and the matching design principle of centrifugal pendulum vibration absorber are discussed.According to the simplified equivalence model and matching design principle,the software of AMESim was used to establish the torsional vibration model of CM3 C powertrain and the simulation model of centrifugal pendulum vibration absorber.The correctness of the model was verified by the real car test in chassis dynamometer.Finally,aiming at the research object CM3 C,simulation results show that the centrifugal pendulum vibration absorber can significantly reduce the torsional vibration amplitude in the range of commonly used speed.And the installation position of the centrifugal pendulum vibration absorber in the powertrain and matching quality are studied.Simulation results show that the vibration reduction effect of the centrifugal pendulum vibration absorber is better when it is mounted on the side close to the engine and the pendulum mass should be matched as much as possible when the installation space allows.