This example shows a closed-loop actuator that consists of a proportional 4-way directional valve driving a double-acting hydraulic cylinder. The cylinder drives a load consisting of a mass, viscous and Coulomb friction, constant force, and a spring. The actuator is powered by a variable-displacement, pressure-compensated pump, driven by a constant velocity motor. Pipelines between the valve, cylinder, pump, and the tank are modeled using the Hydraulic Pipeline blocks.
The plots below show the pressures in the cylinder and the position of the piston.
The plots below show the pressure provided by the pump and the position of the spool in the 4-Way Valve. As the spool position changes the load on the pump increases, causing fluctuations in the pressure at the output of the pump.