LQG Control of Load-Sensing Electro-hydraulic Servo System

The article presents the design, implementation and experimental investigation of linear-quadratic Gaussian controller for load-sensing electro-hydraulic servo system, which is applicable to power steering system of modern mobile machines. In previous studies, the authors have investigated the workability and control performance of the electro-hydraulic power steering (EHPS) system without load-sensing function, which is powered by a fixed displacement pump and an external priority valve. The possibility to develop EHPS with higher energy efficiency motivates the authors to begin series of studies of embedded control systems for load-sensing EHPS, in which the performance strongly depend on the embedded controller. In contrast to the EHPS studied in previous works, this system uses feedback on the piston position of the steering cylinder and on the position of the proportional valve (measured by LVDT). In addition the flow rate is measured but it is not directly involved in the control task. It allows to perform an energy analysis of the entire electrohydraulic steering system.