Dynamic performance improvement of high-speed on/off valve based on pre-excitation bootstrap control

High-speed on/off valve (HSV) is the core control component of digital hydraulic system (DHS), its dynamic performance determines the response speed and control accuracy of DHS. Initial current and driving voltage are the key factors affecting the dynamic performance of the HSV. In this study, a pre-excitation bootstrap control (PEBC) method is proposed to optimize both the initial current and driving voltage of the HSV during its switching process. The initial coil current is generated by pre-excitation control (PEC), which greatly shortens the opening delay time (ODT). Moreover, the driving voltage is impacted to several times the source voltage by bootstrap control (BC) without increasing the source voltage, so that the opening moving time (OMT) is largely decreased. Through numerical and experimental studies, it is demonstrated that the proposed PEBC not only optimizes the dynamic performance of the HSV, but also guarantees its regular switching in under-voltage applications. Compared to the existing three-voltage control algorithm, the PEBC can effectively speed up the moving process of the HSV at different supply pressure, and reduce its ODT by 51.05 % (from 1.43 ms to 0.70 ms) and OMT by 6.62 % (from 1.51 ms to 1.41 ms), respectively. As a summary, the PEBC is verified as a promising and practical method to improve the dynamic performance of the HSV.