by Patrick Opdenbosch

1
EHPV Technology
Advanced Control Techniques for Electro-Hydraulic
Flow Control Valve
by Patrick Opdenbosch
Abstract The current trend in construction
machinery is to use electrically controlled
valves (solenoid valves) instead of manually
operated hydraulic valves. One of the benefits is
that these solenoid valves need not be located in
the operator cab. In addition, the employment of
these electrically driven valves facilitates
computerized control of various machine
functions. The Electro-Hydraulic Poppet Valves
(EHPV), a kind of solenoid valves, are used
herein for flow control in hydraulic machinery.
The flow control through the valve is achieved by
changing the valve restriction coefficient via a
poppet type orifice with pressure compensation
via a Pulse-Width-Modulated current. This
project will explore new algorithms and
applications via theory, simulation and operation
of the valve in Hardware In the Loop (HIL)
simulation facility currently under construction
Proportional-Integral Controller with anti-windup
Hydraulic Circuit Employed for Motor Speed Control
PWM Driver, Single EHPV Model, and Gear Motor
Model
Feedback Control Scheme
Closed-loop Responses Duty Cycle Profile
Closed-loop Response
Motor Speed Control with a Single EHPV A single
EHPV is used to control the speed of a gear
motor.The speed is set as a sine wave with zero
phase, 0.64 Hz, 500 RPM amplitude, and 2000 RPM
offset.
Actuator Displacement Control Using EHPV
Wheatstone Bridge Configuration 4 EHPVs are
used to control the displacement of a passive
actuator. The controller receives a desire
performance criterion (not shown) along with
pressure data from the upstream and downstream
portions of each valve. The controller in turn
sends PWM signals to the EHPVsare used in an
adaptive and trainable algorithm to manipulate
EHPV Mathematical Model Schematic
Non-Linear Model The non-linear mathematical
model developed for the EHPV is based on the
interaction among the Mechanical, Hydraulic, and
Electromagnetic subsystems. It also includes a
model for a Pulse-Width-Modulation driver, which
regulates and modulates the input current to the
EHPV.
(UNDER DEVELOPMENT)
EHPV Modeled 10-90 Step Response
Step Response A simulated step response (10-90
capacity) was obtained for a single EHPV. This
response is for constant pressure drop across the
valve, and varying (by PWM action) the input
current.
Sponsors HUSCO International and FPMC Center

• Advisors
• Dr. Nader Sadegh, Dr. Wayne Book

website http//www.imdl.gatech.edu/opdenbosch
Fall 2003
Email gte608g_at_prism.gatech.edu