Transcript Document

EHPV® Technology
Sponsored by HUSCO Intl. & the FPMC Center
PATRICK OPDENBOSCH
Graduate Research Assistant
NADER SADEGH Ph.D.
Mechanical Engineering Professor
WAYNE BOOK Ph.D.
Mechanical Engineering Professor
Georgia Institute of Technology
George W. Woodruff School of Mechanical Engineering
17 July 2015
AGENDA
• Valve overview.
• Principle of operation.
• Mathematical modeling.
• Simulation results.
• Non-linear controller.
• Hardware-In-the-Loop (HIL)
• Future work.
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
VALVE OVERVIEW
• Electro-Hydraulic Poppet
Valves (EHPV®) are pilot
operated valves used for
flow control in hydraulic
machinery.
• The flow control is achieved by
changing the valve restriction
coefficient via a PWM input
current acting on a pilot and a
poppet type orifice with pressure
compensation.
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
VALVE OVERVIEW
•
Bi-Directional
Capability
•
Pressure
compensation for
consistent current at
flow initiation.
•
Adequate Dynamic
Response
•
Used in wheatstone
configuration
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
VALVE OVERVIEW
Solenoid
Modulating
Spring
Armature
Pilot
COMPONENTS
Control
Pressure
Bias Spring
Pressure
Compensating
Chamber
Main
Poppet
Spring
Connection Port A
Connection Port B
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
PRINCIPLE OF OPERATION
• Forward Flow:
Pressure at port A
is higher than that
at port B.
Port A
Port B
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
PRINCIPLE OF OPERATION
• Forward Flow:
Pressure
compensating
spring acts to
balance
pilot pin
Pilot pin and
armature
displaced due to
hydraulic
imbalance
Port A
Port B
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
PRINCIPLE OF OPERATION
• Forward Flow:
Solenoid is activated
and hydraulic fluid is
drained to low
pressure side
Port A
Port B
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
PRINCIPLE OF OPERATION
• Forward Flow:
Main poppet is
displaced to a new
equilibrium
position allowing a
direct connection
between ports A
and B
Port A
Port B
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
MATHEMATICAL MODELING
• The mathematical modeling is based on the
interaction of three subsystems:
Electromagnetic
Mechanical
Hydraulic
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
MECHANICAL SYSTEM
Modulating
spring
Armature
mass
Bias
spring
Pilot pin
mass
Piston mass
Pressure
compensating
spring
Main poppet mass
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
MECHANICAL SYSTEM
• MODE 1 (closed):
Pilot
Armature
& Piston
Combined
• Pilot-Armature-Piston Dynamics:
• Main Poppet Dynamics:
Main Poppet
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
MECHANICAL SYSTEM
• MODE 2 (open):
Pilot &
Armature
Piston
Main
Poppet
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
MECHANICAL SYSTEM
• MODE 2 (open):
• Pilot-Armature Dynamics:
Pilot &
Armature
Main Poppet
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
MECHANICAL SYSTEM
• MODE 2 (open):
• Piston Dynamics:
Piston
Main Poppet
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
MECHANICAL SYSTEM
• MODE 2 (open):
Pilot &
Armature
• Main Poppet Dynamics:
Piston
Main
Poppet
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
MECHANICAL SYSTEM
• State Constraints
- Main Poppet:
- Pilot & Armature:
Pilot &
Armature
Piston
Main
Poppet
- Piston:
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G.W.W. School of Mechanical Engineering
17 July 2015
Pilot Head
Chamber
HYDRAULIC SYSTEM
Bi-Directional Capability
Control Pressure
Chamber
C2
C1
C
A
C1
C2
B
FORWARD FLOW DIAGRAM
• Forward Flow
A
C
• Reverse Flow
B
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
Pilot Head
Chamber
HYDRAULIC SYSTEM
Control Pressure
Chamber
C
A
C1
B
C2
A
C
B
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
HYDRAULIC SYSTEM
A’
A’
View A’-A’
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G.W.W. School of Mechanical Engineering
17 July 2015
Pilot Head
Chamber
HYDRAULIC SYSTEM
Control Pressure
Chamber
C
A
C1
C2
A
B
Neglecting compressibility effects:
C
B
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G.W.W. School of Mechanical Engineering
17 July 2015
ELECTRO-MAGNETIC SYSTEM
Rsol
Vsol
isol
gmax
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G.W.W. School of Mechanical Engineering
17 July 2015
ELECTRO-MAGNETIC SYSTEM
Rsol
Vsol
isol
gmax
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
ELECTRO-MAGNETIC SYSTEM
Rsol
Vsol
isol
gmax
Hysteresis
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
SIMULATION RESULTS
• EHPV® Step Response (0-90% capacity)
4
15
Step Response for EHPV
Step Response for EHPV
x 10
2.5
2
10
Displacement [mm]
Output Flow [LPM]
Pilot
Main Poppet
5
1.5
1
0.5
0
0
0.95
1
1.05
1.1
1.15
Time [sec]
1.2
1.25
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G.W.W. School of Mechanical Engineering
1.3
-0.5
0.95
1
1.05
1.1
1.15
Time [sec]
1.2
1.25
1.3
17 July 2015
NON-LINEAR CONTROLLER
Motor Speed Control:
CONTROLLER
EHPV
Pump
M
M
Load Motor
Tank
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
NON-LINEAR CONTROLLER
• Scheme:
Closed-Loop Control
+
Open-loop Control
• PI type
• Look-up table
• Generates duty cycle
for PWM driver
• Generate Kv for
given pressure
differential
• Needs control variable
measurement
feedback
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G.W.W. School of Mechanical Engineering
• Trainable/tailored
17 July 2015
NON-LINEAR CONTROLLER
• Closed-loop Control:
Reference
PI
Controller
EHPV
Load
Motor
PWM
Driver
Sampled
Error
100
0
% (Duty Cycle)
PI Controller
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
NON-LINEAR CONTROLLER
• Open-loop Control:
Controller
EHPV
Load
Motor
Converter/
PWM Driver
Look-UpTable
Controller
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
HARDWARE-IN-THE-LOOP
• The Hardware-In-the-Loop (HIL) simulation facility
located at the Intelligent Machine Dynamics
Laboratory (IMDL) will be exploited for model
validation, controller training, and control
implementation.
+12Vdc
Accumulator
Hi-press. filter
Flow meter
Pressure
transmitters
B
A
M
EHPV
Main
Pump
M
Crossover
relief valve
Pressure
relief valve
Lo-press. filter
Load
Tank
Hydraulic Circuit for Single Valve Identification
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
HARDWARE-IN-THE-LOOP
Hardware-In-the-Loop
Facility at IMDL
Hi-press. filter
P
A
T
B
M
M
Main
Pump
Load
4-EHPV®
Tank
Lo-press. filter
Pressure
transmitters
Crossover relief valves
Hydraulic Circuit for 4-Way EHPV® Control Training
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015
FUTURE WORK
1. Model validation for a single valve.
2. Model validation for 4-way directional valve arrangement.
3. Tune-up and test non-linear controller.
4. Development of Robust algorithms for tailored electronic
valve flow coefficient correction.
5. Simulation and testing of four different flow metering
modes, and study their effects.
6. Development of a trainable nonlinear controller to
compensate for inherent system non-linearities such as
hysteresis.
GEORGIA TECH
G.W.W. School of Mechanical Engineering
17 July 2015