Energy-saving cruise control method for heavy-duty transport vehicle based on pump-valve coordinated drive

In order to realize the dual-goal of the improvement in the cruise performance and fuel economy of the heavy-duty transport vehicle (HDTV) for the transfer of the prefabricated box-girder in the construction of high-speed railway, a pump-valve parallel coordinated drive scheme is designed on the basis of the hydrostatic drive system of the HDTV, which combines the load-sensing valve control system and hydrostatic pump control system. Furthermore, the pump-valve coordinated controller (PVC) is also proposed to ensure the cooperation of the two systems, which adopts power following control strategy to control engine speed, the pump and motor displacement respectively, thus achieving the rough adjustment of the cruise velocity. The linear quadratic regulator (LQR) based on the full-state closed-loop feedback is introduced in PVC to control the proportional direction-valve (EPDV) and compensate for the velocity errors, thus realizing the fine adjustment of cruise velocity. A semi-physical experimental test-platform for the HDTV is established to conduct contrast tests between the rule-based controller (RBC) and the proposed PVC under different operating conditions. The results indicate that the PVC effectively reduces the velocity error, the total error is decreased by 80.6% and that of the maximum error is 43.4% under empty-load conditions, and under heavy load conditions, the total error is lowered by 82.1% and that of the maximum error is 46.8%. Moreover, the PVC also brings down the fuel consumption rate of the HDTV, with a maximum reduction of 27.6% and a minimum of 11.4%.