Research on gravity potential energy echelon recovery and speed control of industrial vehicle

This paper proposes an innovative echelon recovery scheme to address inefficiencies in conventional forklift operations, particularly the dissipation of gravitational potential energy during frequent lifting and lowering cycles. The hydraulic oil circuit, with throttling control mechanisms impacting temperature and lubrication, contributes to reduced engine efficiency. The solution involves three load-specific accumulators with predetermined initial pre-inflation pressure and volume. Dynamic models are established for the lifting cylinder, accumulator, fork, and solenoid valve. Using a model predictive control (MPC)-based hierarchical strategy, the upper decision-making layer selects the target accumulator for energy recovery, while the lower predictive control layer utilises MPC to govern fork descent speed. Simulation and experimental results demonstrate a notable 40% enhancement in energy recovery efficiency compared to traditional hydraulic systems. The hierarchical control strategy effectively limits fork descent speed fluctuation to around 10%, significantly improving both gravitational potential energy recovery rates and operational smoothness in forklift fork functionality.