Hydrostatic Transmission with Shuttle Valve

This example shows a hydrostatic transmission with a shuttle valve in the control unit. The 4-way directional valve that controls the motor is actuated by a valve actuator whose input is controlled by two 2-position valves (Shuttle A Valve, Shuttle A1 Valve). The shuttle valve installed between the actuator and the 2-position valves allows the 4-way directional valve to be opened by opening either 2-position valve, and those valves are opened by signals S1 and S2. A fixed orifice is connected to the P port of the two-position valves to decrease flow consumption of the control circuit. Another fixed orifice introduces a small leak from the valve control chamber to avoid this chamber being isolated from the main flow. The motor is connected to pressure line at 1 second and 5 seconds by activating each of the two-position valves.

Model

Valve Block Subsystem

Simulation Results from Simscape Logging

The plots below show the flow rate through the motor and the control signals to valves that connect the motor to the high pressure side of the pump.