How the Foundation library can be used to model systems that span electrical, mechanical and hydraulic domains. In the model, a hydraulic system controls mechanical load position in response to a voltage reference demand. If the reference demand is zero, then the hydraulic actuator (and load) displacement is zero, and if the reference is +5 volts, then the displacement is 100mm.

A two-way valve acting in a closed-loop circuit together with a double-acting cylinder. The controller is represented as a continuous-time transfer function plus a transport delay. The delay allows for the computational time (one discrete time period) plus the zero-order hold (half a discrete time period) when implemented in discrete time. The model is configured for linearization so that a frequency response can be generated. To configure for faster desktop simulation, comment through the transport delay and increase the solver maximum step size.

A physical system model and controller configured for HIL testing. It is derived from example Hydraulic Actuator with Digital Position Controller, ssc_hydraulic_actuator_digital_control. The model has been configured for HIL testing by performing the following steps:

How the fluid in a custom double acting cylinder can cavitate and recover. During the repeating cycle of oscillating pressure, the absolute pressure does not get below absolute zero as the bulk modulus of the homogeneous liquid-gas mixture decreases accordingly at low pressures.