Design of shifting strategy for capacity adjustment device of power reflux hydraulic transmission systems based on working condition identification

The performance of a wheel loader (WL) can be improved with the application of a power reflux hydraulic transmission system (PRHTS) with a capacity adjustment device (CA-device). However, due to CA-device’s unique working principle, the traditional shifting strategy is not suitable for CA-device. Apply traditional shifting strategy to CA-device will result in frequent or incorrect shifting. In order to solve this problem, this paper proposes applying the working condition identification to the CA-device shifting strategy. Combining the working principle of PRHTS with CA-device and the analysis of WL V-condition, the requirement for the working condition identification algorithm of the CA-device shifting strategy is obtained, and a working condition identification algorithm for WL V-condition is designed. Simulation results show that applying the working condition identification algorithm to the CA-device shifting strategy can avoid frequent shifts and incorrect shifts. A hardware-in-the-loop platform is built to verify the real-time performance of the shifting strategy. Results show that the proposed shifting strategy exhibits a satisfactory level of real-time performance.