Introduction

Due to the advantages including a high power-weight ratio and high load capability, fluid power transmission technology has been used in all types of construction machinery. However, there are three typical weaknesses: low energy efficiency, insufficient compatibility, and poor controllability in conventional hydraulic control systems, such as HLS (Hydraulic Load Sensing) systems. To address the aforementioned issue, the independent metering control system (IMCS) is a prominent choice. IMCS is a general term for the system where the meter-in orifice and the meter-out orifice are independently controlled. In addition to energy efficiency, high-precision motion, and force-tracking controls can be achieved simultaneously.