Based on the fractional order sliding mode load observer, this paper presents an antidisturbance speed control method of permanent magnet semi-direct drive transmission system for overhead manned equipment. According to the Lagrange equation, the dynamic model of semi-direct drive transmission system is established. Furthermore, the mathematical model of the permanent magnet synchronous motor (PMSM) is established based on the coordinate transformation theory. Subsequently, the fractional order sliding mode observer (FOSMO), which combines nonsingular terminal sliding mode control and fractional order theory is designed to observe the load disturbance changes in the permanent magnet semi-direct drive transmission system. Then, the concept of "active damping" is used to design the speed loop PI controller, and combined with the designed FOSMO to construct the composite speed controller. The designed composite speed controller is further improved by the anti-saturation design and parameter optimization. The results demonstrate that the designed FOSMO can precisely estimate the load disturbance on the PMSM output shaft. Additionally, the designed composite speed controller can realize stable speed control in the case of complex load disturbance, which meets the anti-disturbance speed control requirements of permanent magnet semi-direct drive transmission system, and the robustness of the control system is further improved by adding the anti-saturation link.

To make the gear better adapt to the high temperature environment, the effects of tooth surface friction and thermal deformation on the dynamic characteristics of the gear were studied. First, based on the basic theory of gear nonlinear dynamics, the backlash model is established considering the effects of thermal deformation. Then, an improved multi-degree-of-freedom nonlinear dynamic model of gears is established taking into account the effects of thermal deformation and friction. The effect of tooth surface friction and thermal deformation on the system motion state is analyzed. Finally, to better analyze the relationship between impact vibration and transmission efficiency, the percussion vibration index is introduced. Compared with the existing research, a gear multi-degree-of-freedom dynamic model is established by considering the influence of tooth surface friction and thermal deformation. The percussion vibration index is introduced as an indicator of gear running health. The research result can provide reference for the optimization and cooling of the gear transmission system.