Post on 17-Mar-2018
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 591
Dr. Monika IvantysynovaMAHA Professor Fluid Power Systems
Design and Modeling of Fluid Power SystemsME 597/ABE 591 - Lecture 13
MAHA Fluid Power Research CenterPurdue University
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© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5912
Displacement Controlled Systems
- Design and modeling of electrohydraulic pump control system
- Displacement controlled linear actuator
- Secondary controlled actuator
- Displacement controlled rotary actuator
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5913
Swash plate control system
Electrohydraulic swash plate control system
Servovalve
Adjustment cylinder
r C
F
Xcom
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5914
Swash plate moment MSx
f(pi) instantaneous cylinder pressure
pe
Case pressure pe
Qr
QSB
QSK
QSGIT AT
Real profile π
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5915
Swash plate moment MSx
Δp = 300 barn = 2000 rpm
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5916
Influence of the Valve Plate Design
Vi = 100 %Δp = 100 barn = 2000 rpm
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5917
Swash Plate Control Mechanism
r c
ß
ß
r cConnecting rod joint
Connecting rod less
Sliding motion
or
B
C
(1)
(2)
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5918
FS=FN
FNSi
FSzi
FSyi
Swash Plate Bearing Design Examples
must be carried by swash plate bearing
FSy
FSz
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 5919
Swash Plate Bearing – Design Examples
Swash plate
Shaft axis
Swash plate
Shaft axis
z
y
must be carried by swash plate bearing
x
z
In case of variable displacement pumps veryoften radial bearings are used
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59110
Swash Plate Bearing – DesignExamples
Swash plate bearings
Control cylinder
Mechanical feedback
Swash plate
Control valve
Charge pump
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59111
Design of swash plate control system
r C
xxmax
Swash plate control cylinder
FpA pB
m… moveable mass
d… coefficient of viscous friction
c… spring constant
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59112
Design of swash plate control system
Selection of control valve
QA QB
pA pB
p0
pnomSV=70 bar
Valve size:
Required flow rate:
1 2d
y
Q=QA=QB
F
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59113
Design of swash plate control system
Main design requirements:
Low power
High bandwidth
Min time tmin for ß=0 to ß=ßmax (20 ms up to 200 ms)
Maximal flow rate
ti
Frequency response
Servovalve input current
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59114
Design of swash plate control system
Pressure required to realized necessary acceleration
Pressure required for velocity
Maximal value
Maximal value Qnom
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59115
Design of swash plate control system
Supply pressure p0
Swash plate moment MSx
Effective piston area of control cylinder
Servovalve or proportional valve size
Response time, adjusting time Q
Swash plate controller
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59116
Mobile Robots
Advanced Energy Saving Actuator Technology
New Valveless Rotary Actuator
Successfully testedon laboratory test rig
Displacement controlledactuator
Controller
Controller
Machine Control
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59117
Advanced Energy Saving Actuator Technology
Pump control instead valve control
New Linear Actuator
Eng x
u
Controller
What are the advantages ?
Better Utilization of Primary Energy
Energy Recovery
Easier to Control
System Simplification
Less weight & space
Less fuel consumption
Displacement controlled actuator
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59118
Displacement controlled actuator
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59119
New linear actuator with single road cylinder
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59120
Displacement controlled rotary actuator
Controller
Motor Module
Pump control
Engine
Pump module
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59121
Possible applications?
Steering System
Stabilizer – roll control
Vehicle Suspension System – active damping control
Power Split Drive Technology using Hydrostatic Transmission
Cabriolet Roof Actuation and others
Systems with linear or rotary actuator movement
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59122
FSV
DCVU x
U p
Front Rear
U p
Active roll stabilizationValve controlled system
Today
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59123
Active roll stabilizationAlternative Solution
FSV
FrontRear
Pump Control Pump Control
Fuel savings by valveless actuator technology
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59124
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EHA with fixed displacement pump
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59125
EHA with variable displacement pump
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59126
Requires constant pressure supplySecondary controlled actuator
p0
pA pB
QA QBA
φxQLi
F
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59127
Secondary controlled actuator
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59128© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 591
Secondary controlled actuator
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© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59129
Hydraulic actuator principles
© Dr. Monika Ivantysynova Design and Modeling of Fluid PowerSystems, ME 597/ABE 59130
Proportional valve
Servovalve
LS- valve
Hydraulic actuator principles