Research on power matching of construction machinery volume throttle speed control system based on double-variable hydraulic source

Abstract

The volume throttle speed control system, known for its speed regulation accuracy and energy efficiency, is widely used in construction machinery. When combined with a double-variable hydraulic source that allows simultaneous control of motor speed and pump swashplate angle(SWA), the system gains greater flexibility but also introduces additional nonlinearities. To address this issue and enhance power matching performance, a nonlinear flow model is first developed, considering motor speed, SWA, and pump supply pressure. Based on this model, a control structure is designed that integrates a continuous sliding mode controller to improve accuracy and robustness under dynamic conditions. Second, a dynamic variable pressure margin (VPM) strategy is proposed to achieve real-time power matching. It analytically computes the target pressure margin (PM) based on a characterization factor $\lambda$ , allowing users to flexibly balance energy consumption and machine responsiveness. Using load data from a 2-ton electric excavator’s digging cycle as a benchmark, the double-variable hydraulic source with the proposed control structure showed an improvement of approximately 24.9% in control performance compared to traditional hydraulic sources. The application of the VPM strategy resulted in power matching optimizations of 23.0% and 15.3% for the double-variable and traditional hydraulic sources, respectively. These results validate the superiority of the proposed control structure and the effectiveness of the VPM strategy.