EH Valves

The robot arm utilizes three different types of electro-hydraulic valves, a servo valve, a proportional directional control valve and a programmable valve. The valves and hoses are fitted with quick-disconnects so that any valve can be easily used on any circuit or allow connection to a stand-alone flowmeter.

Servo and Proportional Valves:

The proportional valve is a Parker D3FXE01HCNBJ001 proportional directional control valve with a maximum flow of 5.5 gpm. The servo valve is a Parker BD760AAAN10 servo valve with a maximum flow of 10 gpm.

Programmable Valves:

The programmable valve is intended to replace a standard four-way valve with a number of independent two-way valves, in this case five. The use of a programmable valve allows the head-end and rod-end flows to be decoupled and independently controlled. The result is a very flexible valve with the ability to have flow curves programmed in software instead of built into the hardware. The result is a standard valve that can be incorporated into nearly any piece of equipment and programmed specifically for the machine as well as providing a number of unique and efficient flow configurations.

The specific two-way valves utilized are Vickers EPV 10-A-8H-12D-U-10 2-way proportional flow control valves with Vickers C-10-2 SAE8 manifolds. The valve is a solenoid-actuated cartridge-type valve with pressure compensation. The maximum rated flow of the valve is 8 gpm and the rated bandwidth of the valve at -3 dB is approximately 32 Hz with a phase lag of 67.5 deg. The valves are driven by a pulse width modulated signal produced by the Vickers EHH-AMP-702-J-20 power plugs. The PWM frequency is 1200 Hz with a dither frequency of 120 Hz. The power plugs have adjustable gain, deadband and dither currents.

The configuration of the cartridge valves is the key to the functionality of the programmable valve. Click here to see the configuration of the five cartridge valves and the implemented hardware.