Development of a dual-mode electro-hydrostatic actuator with serial-parallel hybrid configured piezoelectric pumps

Smart materials-based electro-hydrostatic actuator (EHA) plays an important role in the power-by-wire technology for the next generation of more electric aircraft. However, the output flow of a smart materials-based EHA is relatively low to narrow down its practical applications. To address this issue, a piezoelectric material-based dual-mode electro-hydrostatic actuator (DMEHA) is proposed in this work. The output flow can be improved by adopting two piezoelectric pumps without sacrificing the carrying capacity. In addition, a hybrid serial and parallel configuration for the two pumps is realized for the adaptability of different actuation requirements. Mathematical modeling and parameter identification are conducted and presented in detail for the designers. A physical prototype is fabricated and a series of experiments are carried out to investigate its characteristics. Results indicated that the DMEHA achieves a maximum output flow of 1.17 l min⁻¹ at 360 Hz under the serial mode and the blocking load up to 40 kg. The corresponding maximum output flow in the parallel mode can reach 1.96 l min⁻¹ at 420 Hz, and the blocking load is 20 kg.