Closed-Loop Actuator with Variable-Displacement Pressure-Compensated Pump

Open Model

This example demonstrates closed-loop control of a hydraulic actuator position. The model uses a 4-way directional valve to control the position of a double-acting hydraulic actuator. The actuator acts against a load, which the model represents with blocks that model mass, viscous damping, Coulomb friction, constant force, and spring. The actuator is powered by a variable-displacement, pressure-compensated pump, which is driven by a motor. Pipe (IL) blocks model the pipelines between the valve, cylinder, pump, and tank.

Model

Simulation Results from Scopes

Simulation Results from Simscape Logging

The plots below show the pressures in the cylinder and the position of the piston.

The plots below show the pressure differential created by the pump, pump displacement, and the position of the spool in the 4-way valve. The pressure value is well controlled under 6.6 MPa, which is the sum of the set pressure differential of 6 MPa and the pressure regulation range of 0.6 MPa. The pump displacement is negatively proportional to the pressure differential, which prevents excessive pressure at the pump outlet.

See Also