An energy-saving control strategy with load sensing for electro-hydraulic servo systems

Abstract

The electro-hydraulic servo system (EHSS) usually demonstrates a lower efficiency in comparison to other available actuation methods. Thus, an energy-saving control strategy based on a load-sensing structure is developed in this study to improve the system efficiency of EHSS. The presented controller employs variable supply pressure control (VSPC) to reduce the pressure loss across the valve. Unlike the existing VSPC, a load-sensing structure that consists of a load-sensing pump, a proportional relief valve (PRV), and a throttle valve is proposed. Therefore, the overflow loss can also be decreased. Additionally, an adaptive backstepping sliding mode control is presented for the purpose of position tracking. Compared with the fixed displacement system, the proposed method is capable of saving 62.5 % and 90 % energy for the harmonic reference tests and multi-step reference tests, respectively, during the task of position tracking.