Modeling and Analysis of Gear Shifting Process of Non-Synchronizer AMT Based on Collision Model

Abstract

In the gear shifting process of a clutchless automated mechanical transmission (AMT), the potential collision between sleeve and dog gear may increase both vehicle jerk and gear changing duration. Therefore, the gear shifting process's mechanism analysis and dynamic modeling are the essential prerequisites to improve gear shifting quality. This paper analyzes the potential collision between the sleeve and the dog gear which both with concave-convex profiles, the tooth-side chamfer considered. To model the collision process, a fast-determining collision face method based on an intersection map is proposed, and the Monte Carlo method and equivalent depth are employed to calculate the collision stiffness. Then, the stiffness-damping model of the collision process and an 8-degree-of-freedom dynamic model of the gear-shifting system are established. Finally, taking a two-speed clutchless and non-synchronizer automated mechanical transmission (NSAMT) as an example, the established dynamic model of the gear-shifting system is applied, and simulation verification is performed in Matlab/Simulink. The simulation results show that the established model can accurately reflect the changes of forces, speeds, and displacements of sleeve and dog gears during the collision and effectively reflect processes of the disengagement of the sleeve, the speed changes in active synchronization, the engagement of sleeve and gear keeping. Besides, the results also show that the tooth-side chamfer will increase the disengagement time, while it is conducive to gear keeping, and that unloading the drive motor can decrease the disengagement time due to the existence of the tooth-side chamfer.

Research on Precise Tracking Control of Gear-Shifting Actuator for Non-Synchronizer Automatic Mechanical Transmission Based on Sleeve Trajectory Planning

“…During the shifting process, a significant disparity in speed between the engaging sleeve and the gear ring to be engaged can result in prolonged shifting duration, substantial impact during shifting, and even failure to complete the shift. Recent research has extensively explored active angle alignment control as a means of synchronizing the speed of the sleeve with that of the target gear through coordinated regulation of the shift actuator and drive motor [19][20][21]. This approach aims to minimize shift time and mitigate impact during shifting [6,14,22].…”

“…Based on each stage's dynamic characteristics in the model, a gear-shifting control strategy incorporating speed active synchronization and angle active synchronization is devised to ensure precise synchronization between the sleeve and joint gear ring during gear shifts. The collision process between the sleeve and the target gear ring, considering tooth-side chamfering, was analyzed and simulated by Xiaotong Xu et al [14,21]. The collision stiffness was calculated using the Monte Carlo method and equivalent depth.…”

Analysis of possible faults and diagnostic methods of the Cartesian industrial robot

“…The main advantages of the gear train are high efficiency, compactness, and high rotational speed, which allows it to be used at high power [21][22][23]. On the other hand, the disadvantages of the gear train which reduce the scope of its application are noise, increased dynamic load, frequent need for lubrication to avoid tooth jamming and abrasion, transmission rigidity [21][22][23]. Gear drives are mainly used for two purposes [24]: force transmission between parallel shafts and conversion of translational motion into rotary motion and vice versa.…”