Dynamic simulation of a hydromechanical transmission system during gearshifting

A power-shift clutch is one of the key components in a hydromechanical transmission system that includes torque converter, power-shift clutches, mechanical gearshift device and continuously steering mechanism, etc. During gearshifting, the output torque perturbation, which caused by the friction torque of the clutch, produces a dynamic load. The friction torque of the clutch is affected by the friction coefficient and the control oil pressure when the configuration parameters of the clutch are unchanged. The hydromechanical transmission system completes gearshift by changing different clutches. Based on the physical and the mathematical models, a dynamic simulation model was developed in the paper by using the Matlab/Simulink toolbox. It can simulate the dynamic performance effectively when two clutches change their duties (offgoing and oncoming). With the help of the simulation model, the designer can predict the performance of the production during design process. It lays a foundation for improving the configuration of a clutch and designing a control system.