Dynamic modelling and optimal design of a clutch actuator for heavy-duty automatic transmission considering flow force

Abstract With the rapid development of heavy-duty vehicles, increasing attention has been paid to the performance of high-power automatic transmission. An electro-hydraulic actuator, as a key component in automatic transmission, is crucial to the shifting quality. In this study, we develop a dynamic model of an electro-hydraulic actuator for heavy-duty vehicles, and adopt the artificial bee colony (ABC) algorithm to optimize the structural parameters to improve the ride comfort and fuel economy. First, a detailed model considering the flow force is developed to describe the motion inside the actuator based on the theory of fluid dynamics. Then the key design parameters, which affect the shifting performance significantly, are identified by combining the Bode plots and sensitivity analysis. Finally, the electro-hydraulic actuator is optimized to ensure the actual curve approximates the ideal trajectory while shortening the clutch pressure response time maximally by using the ABC algorithm. In comparison with the original parameters, the optimized design shows a major improvement in the rapid response and precise control of gear shifting. This investigation provides an efficient approach to design the structure parameters of clutch actuators to increase their shifting performance.