Simulation of a Mobile Equipment Hydraulic Control System

This paper describes a simulation of a mobile equipment closed loop hydraulic position control system, performed on a digital computer using a modeling program. Features are cylinder nonsymmetry, bulk modulus varying as a function of pressure and entrained air, valve pressure/flow, and pump pressure/flow characteristics. Results indicate that the most critical parameters, based on effect on performance and difficulty in predicting their values, are damping and bulk modulus. The simulation can be readily extended to include other effects such as cylinder and load stiction and Coulomb friction, time varying externally applied loads, and valve underlap or overlap.