Study on Dynamic Matching and Dynamic Characteristics of Hydrostatic Transmission System of Forklift Truck

TL;DR

This paper develops a control strategy for hydrostatic transmission systems in forklift trucks, improving acceleration, response speed, and control precision through dynamic matching and compensation mechanisms.

Contribution

It introduces a novel power matching strategy and dynamic compensation mechanism tailored for hydrostatic drive systems in forklifts, enhancing their dynamic performance and load adaptability.

Findings

Improved acceleration and response speed in forklift hydrostatic systems.

Enhanced control accuracy and load adaptability.

Validated effectiveness through multiple operating condition tests.

Abstract

In the fields of agricultural machinery, construction equipment, and special-purpose vehicles, hydrostatic transmission (HST) drive systems have witnessed a significant increase in market penetration. With the rapid development of intelligent and environmentally friendly trends, higher requirements have been imposed on HST control systems regarding operational efficiency, control accuracy, and adaptability to working conditions. This study focuses on a forklift truck drive system equipped with a dual variable-displacement pump-motor assembly. A mathematical model of the HST system was constructed, with detailed analysis of each stage during vehicle acceleration. A power matching strategy was proposed to enhance dynamic performance, whose core concept consisted of three elements: 1) correlating the driver's pedal signal with the target engine speed of the diesel engine, 2) dynamically adjusting motor displacement to maximize acceleration capability, and 3) coordinating pump displacement variations. Furthermore, a dynamic compensation mechanism for control variables was introduced to improve system responsiveness. The controller was evaluated under multiple operating conditions, with results demonstrating superior acceleration performance, rapid response, and precise control characteristics. These results validate the effectiveness of the proposed control strategy and its robust load adaptability in hydrostatic drive systems.