Abstract:  There was an impact problem caused by the change of clutch engagement pressure in the shift process of power transmission, therefore, a clutch engagement hierarchical control strategy based on model predictive control (MPC) was proposed. Firstly, based on MPC algorithm control, the effective slip point was calculated according to the relevant parameters, and the proportional valve pressure control curve was formed, so that the corresponding proportional valve was controlled in stages to achieve rapid response and smooth friction acceleration. Then a highorder dynamics state space based on MPC was established, the desired trajectory equation and objective function were constructed to optimize the input of the proportional valve. Finally, through the establishment of the power transmission shift model, shift control strategy and simulation, the control method was tested according to the acceleration throttle opening curve. The research results show that, comparing with the traditional PID control, the clutch engagement speed is faster by using this method, the impact degree is reduced by about half, and the slip time is reduced by 8%. Under the action of the hierarchical control strategy, it can improve the ride comfort of the whole vehicle by using the direct-drive power transmission in construction machinery.

Key words:  transmission; hierarchical control strategy; clutch; model predictive control (MPC)

WANG Yi-min, HU Jian-fei, ZHANG Wei, et al. Hierarchical control strategy of transmission in direct drive power transmission based on MPC［J］.Journal of Mechanical & Electrical Engineering, 2022,39(1):18-25.