Introduction to Electro-hydraulic Proportional and Servo

Transcription

Introduction to Electro-hydraulic
Proportional and Servo Valves
1
Servo
Valves
Proportional Valves
Mobile bankable
Style, Threaded
Cartrdige Style
NFPA Mounting
Without Spool
Position
Feedback
NFPA Mounting
With Spool
Position
Feedback
Servo
Performance,
Closed Loop
Valves with Spool
Position Feedback
Servo Valves
With either
Mechanical or
Electrical
Feedback (spool
position).
Parker Models
Pulsar VP,
VPLs.
D*FWs, D*FTs’
D*FXs’
D*FP
D*FHs
D*1FH
BDs’
DYs’
SEs’
Mechanical
Construction
(spool shift)
Electro-Hydraulic
Pilot,
Mechanical
(spring) Return
Electromagnetic
Force,
Mechanical
(spring) Return
Electromagnetic
Force,
Mechanical
(spring) Return
Electromagnetic
Force, Mechanical
(spring) Return
Torque Motor Pilot
Control
Balance PSI spool
Control
Hysteresis
3…..7%
3…7%
0.03…..1%
0.1….5%
0.1…..0.5%
Frequency
Response
< 10 Hz
10…50 Hz
10….70 Hz
50...150 Hz
100…200 Hz
Center Lap
Condition
Overlap 5…20%
Zero Overlap
Zero Overlap
Operating
Pressures Limits
(Drop across
metering edge).
1000…2000 PSI
1000…3000 PSI
None
Closed Loop
Position & Force
Closed Loop
Position & Force
Applications
2
Open Loop Control
Low End Closed
Loop Position
Meter Out Circuit
P to A
B to T
T
Free flow into the “cap” end
Metered Flow out the “head”
end.
3
P
A
T
B
Meter Out Circuit
P to B
A to T
T
Free flow into the “cap” end
Metered Flow out the “head”
end.
4
P
A
T
B
Electrohydraulic Valves
P to A
B to T
T
Shift Spool slightly to create
metering Orifice
5
P
A
T
B
Servo
Valves
Proportional Valves
Mobile bankable
Style, Threaded
Cartridge Style
NFPA Mounting
Without Spool
Position
Feedback
NFPA Mounting
With Spool
Position
Feedback
Servo
Performance,
Closed Loop
Valves with Spool
Position Feedback
Servo Valves
With either
Mechanical or
Electrical
Feedback (spool
position).
Parker Models
Pulsar VP,
VPLs.
D*FWs, D*FTs’
D*FXs’
D*FP
D*FHs
D*1FH
BDs’
DYs’
SEs’
Mechanical
Construction
(spool shift)
Electro-Hydraulic
Pilot,
Mechanical
(spring) Return
Electromagnetic
Force,
Mechanical
(spring) Return
Electromagnetic
Force,
Mechanical
(spring) Return
Electromagnetic
Force, Mechanical
(spring) Return
Torque Motor Pilot
Control
Balance PSI spool
Control
Hysteresis
3…..7%
3…7%
0.03…..1%
0.1….5%
0.1…..0.5%
Frequency
Response
< 10 Hz
10…50 Hz
10….70 Hz
50...150 Hz
100…200 Hz
Center Lap
Condition
Overlap 5…20%
Zero Overlap
Zero Overlap
Operating
Pressures Limits
(Drop across
metering edge).
1000…2000 PSI
1000…3000 PSI
None
Closed Loop
Position & Force
Closed Loop
Position & Force
Applications
6
Open Loop Control
Low End Closed
Loop Position
Sectional Valves
VPL Series
C2
C1
Limiter
Compensator
P
7
T
Sectional Valves
VPL Series
Pulsar
Solenoid
Cyl. Relief
Anti-Cav. Check
C1
Pressure
Limiter
Manual
Override
Flow
Limiters
Optional
L.S. Port
8
Individual
Compensator
C2
Pressure
Limiter
Sectional Valves
VPL Series (C1 Energized)
9
VPL Main Spool
8 Flow Rates (1.3, 2.5, 4, 7, 11, 17, 24, 30 GPM)
OCM
VOC
CC
Spool
Meter-In Lands
Marking
Ex. 524
Centering Spring
200 or 350 PSI
Meter-Out Lands
Detent & Friction-Lock also Available
10
Regenative
Options
Compensation, VPL
Series
• Pressure compensation maintains a constant flow
regardless of pump pressure, load pressure, or any other
load in the system
• This means when running multiple sections at the same
time, there will be no change in speed
Standard Spool / Springs for
complete flow range
11
VPL Compensator
Components
3 Sizes
of Shims
(.003” .008” .025”)
12
Servo
Valves
Proportional Valves
Mobile bankable
Style, Threaded
Cartridge Style
NFPA Mounting
Without Spool
Position
Feedback
NFPA Mounting
With Spool
Position
Feedback
Servo
Performance,
Closed Loop
Valves with Spool
Position Feedback
Servo Valves
With either
Mechanical or
Electrical
Feedback (spool
position).
Parker Models
Pulsar VP,
VPLs.
D*FWs, D*FTs’
D*FXs’
D*FP
D*FHs
D*1FH
BDs’
DYs’
SEs’
Mechanical
Construction
(spool shift)
Electro-Hydraulic
Pilot,
Mechanical
(spring) Return
Electromagnetic
Force,
Mechanical
(spring) Return
Electromagnetic
Force,
Mechanical
(spring) Return
Electromagnetic
Force, Mechanical
(spring) Return
Torque Motor Pilot
Control
Balance PSI spool
Control
Hysteresis
3…..7%
3…7%
0.03…..1%
0.1….5%
0.1…..0.5%
Frequency
Response
< 10 Hz
10…50 Hz
10….70 Hz
50...150 Hz
100…200 Hz
Center Lap
Condition
Overlap 5…20%
Zero Overlap
Zero Overlap
Operating
Pressures Limits
(Drop across
metering edge).
1000…2000 PSI
1000…3000 PSI
None
Closed Loop
Position & Force
Closed Loop
Position & Force
Applications
13
Open Loop Control
Low End Closed
Loop Position
How does it Work?
(No Spool Feedback)
“Integrated Electronics”
(PWD Amplifier)
Solenoid “B”
Solenoid “A”
“Command Signal” based upon a % of Maximum. Typically 0 to +/- 10 VDC.
Amplifier converts Voltage (Command) into proportional Current (Typically
0..2.1 Amps).
Variable DC current into solenoid assembly produces Electromagnetic Force,
proportional to current applied.
By matching Opposition Spring Force to Solenoid Force, Proportional Spool
Movement is obtained.
14
How does it Work?
Proportional Solenoid Construction
Frame
Winding
Plunger
(armature)
Push pin
15
How does it Work?
Solenoid Operation
.5 VDC 50%
.
16
Proportional Valve Spool
Designs
V-Notch Spool
C-Notch Spool
17
FLOW AREA %
Proportional Valve Spool
Designs
P-A-B-T = 145 PSI
100
90
80
70
60
50
40
30
20
10
0
FLOW AREA %
0
40
60
SPOOL SHIFT, %
8
100
8
100
P-A-B-T = 145 PSI
100
90
80
70
60
50
40
30
20
10
0
0
18
20
20
40
60
SPOOL SHIFT, %
V-Notch - Bleed Center
bleed notch
primary
metering
notch
19
Proportional Valve Deadband
Ps
T
A
20
T
B
Positive Overlap + Spring Force
+ Q
+ I
Mechanical Spool
Overlap (Deadband)
21
Deadband Eliminator
100 KΩ
100 KΩ
100 KΩ
+
Vin
100 KΩ
+
+s
+ DBE
100 KΩ
−s
− DBE
+ VCC
22
− VCC
100 KΩ
+
Vout
Deadband Compensation
+ Q
+ I
Deadband
Compensation
23
Deadband Compensation
+ Q
+ I
Deadband Over
Compensated
24
Valve Drivers (Open Loop) On Board
Integrated Electronics
25
Integrated Electronics (Pot adjustments)
Ramp Pots
Max Pots
MIN Pots
26
Integrated Electronics (PC Adjustments)
Digital Onboard Electronics
D1FB*0 OBE
27
Deadband Eliminator P to A flow Path
Ps
T
A
28
T
B
Deadband Eliminator (P to B flow Path)
Ps
T
A
29
T
B
Servo
Valves
Proportional Valves
Mobile bankable
Style, Threaded
Cartrdige Style
NFPA Mounting
Without Spool
Position
Feedback
NFPA Mounting
With Spool
Position
Feedback
Servo
Performance,
Closed Loop
Valves with Spool
Position Feedback
Servo Valves
With either
Mechanical or
Electrical
Feedback (spool
position).
Parker Models
Pulsar VP,
VPLs.
DF**, ERVs
D*FWs, D*FTs’
D*FXs’
D*FH
D*FMs
D*1FH
BDs’
DYs’
SEs’
Mechanical
Construction
(spool shift)
Electro-Hydraulic
Pilot,
Mechanical
(spring) Return
Electromagnetic
Force,
Mechanical
(spring) Return
Electromagnetic
Force,
Mechanical
(spring) Return
Electromagnetic
Force, Mechanical
(spring) Return
Torque Motor Pilot
Control
Balance PSI spool
Control
Hysteresis
3…..7%
3…7%
0.03…..1%
0.1….5%
0.1…..0.5%
Frequency
Response
< 10 Hz
10…50 Hz
10….70 Hz
50...150 Hz
100…200 Hz
Center Lap
Condition
Overlap 5…20%
Zero Overlap
Zero Overlap
Operating
Pressures Limits
(Drop across
metering edge).
1000…2000 PSI
1000…3000 PSI
None
Closed Loop
Position & Force
Closed Loop
Position & Force
Applications
30
Open Loop Control
Low End Closed
Loop Position
Spool Feedback, How does it Work?
Spool Position LVDT
“Integrated Electronics”
(PWD Amplifier)
Solenoid “B”
Solenoid “A”
•Same basic operation as non-feedback valves, but
“outcome” is measured and corrected to match desired
result.
•“Closing the Loop”.
31
Spool Feedback Device
Linear Variable Differential Transformer
Input
V DC
Oscillator
Primary
Spool
Core
Secondary
Output
V DC
Demodulator
32
Secondary
L.V.D.T.s
33
Spool Feedback Devices
(Electrical Schematic-Integrated
Electronics)
Disturbances
adj
CMD +
Error
I
F
A
FB LVDT
34
X
Internal Closed Loop
Force
u s
Command
Signal
Valve position feedback
35
Sample Application
36
Kv Sizing
37
Non-Symmetrical Spools
38
Sample Application, Number 2
39
Non-Symmetrical Spools
(P-A-B-T = 145 PSI)
10
7.5
Flow Rate, GPM
5
2.5
0
-10
-7.5
-5
-2.5
0
-2.5
2.5
-5
-7.5
-10
Valve Command, Volts
40
5
7.5
10
Common Procedure
The manufacturer can choose to take a
standard 10gpm valve with normally 4 notches
on each land and only cut two notches in the
land that will be connected to the small area of
the cylinder.
3 notches instead of 4
4 notches instead of 6
2 notches instead of 6…
41
Non-symmetrical Spools
P
T
A
1.7 holes
A
.85holes
B
PS
1.7 holes
42
.85holes
T
B
Sample Application No. 2 with NonSymmetrical Spool
43
Flow Force Effects Proportional
Valves
Flow
∆X
44
Flow Force Performance
Operating Limits
Curves show Valve
Performance over
entire Pressure
Range
45
Servo
Valves
Proportional Valves
Mobile bankable
Style, Threaded
Cartrdige Style
NFPA Mounting
Without Spool
Position
Feedback
NFPA Mounting
With Spool
Position
Feedback
Servo
Performance,
Closed Loop
Valves with Spool
Position Feedback
Servo Valves
With either
Mechanical or
Electrical
Feedback (spool
position).
Parker Models
Pulsar VP,
VPLs.
DF**, ERVs
D*FWs, D*FTs’
D*FXs’
D*FH
D*FMs
D*1FH
BDs’
DYs’
SEs’
Mechanical
Construction
(spool shift)
Electro-Hydraulic
Pilot,
Mechanical
(spring) Return
Electromagnetic
Force,
Mechanical
(spring) Return
Electromagnetic
Force,
Mechanical
(spring) Return
Electromagnetic
Force, Mechanical
(spring) Return
Torque Motor Pilot
Control
Balance PSI spool
Control
Hysteresis
3…..7%
3…7%
0.03…..1%
0.1….5%
0.1…..0.5%
Frequency
Response
< 10 Hz
10…50 Hz
10….70 Hz
50...150 Hz
100…200 Hz
Center Lap
Condition
Overlap 5…20%
Zero Overlap
Zero Overlap
Operating
Pressures Limits
(Drop across
metering edge).
1000…2000 PSI
1000…3000 PSI
None
Closed Loop
Position & Force
Closed Loop
Position & Force
Applications
46
Open Loop Control
Low End Closed
Loop Position
VCD®…Milestone for High
Performance Valves
D1FP (NG6) valve as pilot valve for D*1FP
integrated drive
electronics
Voice Coil Drive VCD®
valve body
spool-sleeve
assembly
spring assembly
fail-safe position
47
VCD®…Milestone for
High Performance Valves
Parker Voice Coil Drive (VCD®) technology for
highest precision
integrated feedback
system
pushpin
48
carriage
coil
permanent
magnet
housing
Performance Valves
VCD® principle, moved coil in magnetic field
-Fo
Β
Fo
X
−Ι
Ι
Fo = B . I . l
N S
B = magnetic flux density
I = electrical current
l = wire length (winding)
49
permanent magnet
non-magnetic material
winding
iron (magnetic)
Performance Valves
Characteristics of force in comparison
F[N]
F [N]
0
x [mm]
conventional solenoid
force dependent of stroke
50
0
x [mm]
Voice Coil Drive
force independent of stroke
Servo Solenoid/Voice Coil Valves
“Line to Line” Lap
Or “Axis Cut”
No Deadband
B
A
Sleeve
51
T
Ps
T
Housing
Spool and Sleeve Arrangement
52
Spool Lap Conditions
(Positive) Overlap
Zerolap
(Negative) Underlap
53
Spool Lap Conditions
(Positive) Overlap
Zerolap
U = 40%
U = 40%
U = 20%
U = 20%
U = 0%
U = 0%
54
Flow windows
•Standard Symmetrical Laps
•“Knick Servo Cuts”
55
Servo
Valves
Proportional Valves
Mobile bankable
Style, Threaded
Cartrdige Style
NFPA Mounting
Without Spool
Position
Feedback
NFPA Mounting
With Spool
Position
Feedback
Servo
Performance,
Closed Loop
Valves with Spool
Position Feedback
Servo Valves
With either
Mechanical or
Electrical
Feedback (spool
position).
Parker Models
Pulsar VP,
VPLs.
DF**, ERVs
D*FWs, D*FTs’
D*FXs’
D*FH
D*FMs
D*1FH
BDs’
DYs’
SEs’
Mechanical
Construction
(spool shift)
Electro-Hydraulic
Pilot,
Mechanical
(spring) Return
Electromagnetic
Force,
Mechanical
(spring) Return
Electromagnetic
Force,
Mechanical
(spring) Return
Electromagnetic
Force, Mechanical
(spring) Return
Torque Motor Pilot
Control
Balance PSI spool
Control
Hysteresis
3…..7%
3…7%
0.03…..1%
0.1….5%
0.1…..0.5%
Frequency
Response
< 10 Hz
10…50 Hz
10….70 Hz
50...150 Hz
100…200 Hz
Center Lap
Condition
Overlap 5…20%
Zero Overlap
Zero Overlap
Operating
Pressures Limits
(Drop across
metering edge).
1000…2000 PSI
1000…3000 PSI
None
Closed Loop
Position & Force
Closed Loop
Position & Force
Applications
56
Open Loop Control
Low End Closed
Loop Position
Servo Valve – Double Flapper Design
Torque Motor
Spool & Sleeve
Assembly
57
Feedback Spring
Servo Valve – Double Flapper Design
Armature
Frame
Coil
Coil
N
N
S
S
Flapper
Flexure Tube
Nozzle
58
Feedback Spring
and Ball/Ruby
Servo Valve - Principles of Operation
Valve at “Null”
N
N
S
S
P
P
R
P
A
59
R
P
B
Servo Valve - Principles of Operation
Valve With Current Applied
(+)
(-)
N
N
S
S
P
P
R
P
A
60
R
P
B
Flow Forces Not an Issue with Servo
Valves
61
Servo ‘s Performances
62
Symbology
Proportional Valve with Spool
Feedback
Proportional Directional Valve
u
Servo Performance Proportional Valve
u
63
s
s
Servo Valve
Terminologies
64
Pressure Gain
40% pressure change
1% command change
80% rise
2% command
65
Hysteresis
Decreasing Flow
from Valve
100%
90%
% of Full Open Flow
80%
70%
60%
Hysteresis
50%
40%
Mechanical
Spool
Overlap: the
Deadband
30%
20%
10%
Increasing Flow
from Valve
0%
1
66
2
3
4
5
Input Signal
6
7
8
9
10
Repeatability
100%
90%
Increasing
Flow
Only
% of Full Open Flow
80%
70%
60%
50%
Repeatability
40%
30%
20%
10%
0%
1
67
2
3
4
5
Input Signal
6
7
8
9
10
Valve Frequency
Two methods: frequency response, step
response (we’ll use frequency response)
Thru center
Bias or one sided
Q
Q
CMD
CMD
offset
bias
68
Valve Frequency Response
0° Phase Lag
CMD
Valve
FB
90° Phase Lag
90° Phase Lag = ¼ cycle
The input frequency which creates a phase lag of 90° is the
defining characteristics of a valve and is referred to as
bandwidth
69
Frequency Response
• To measure the response of a control
valve, a sinusoidal varying input signal is
applied, effectively switching the valve
from one working position to the other
• At a very low frequency the valve is able
to follow the demand signal closely
• As the frequency increases the valve
becomes less able to follow the input
signal precisely
70
Frequency Response
• The output starts to lag behind the input,
then the valve is not able to reach the
maximum output position before the input
signal reverses
• The lag between the input and output is
known as phase lag
• The reduced output apparent at higher
frequencies is known as attenuation
71
Valve Frequency
Frequency response (sine wave) to make catalog data
72
Servo
Valves
Proportional Valves
Mobile bankable
Style, Threaded
Cartrdige Style
NFPA Mounting
Without Spool
Position
Feedback
NFPA Mounting
With Spool
Position
Feedback
Servo
Performance,
Closed Loop
Valves with Spool
Position Feedback
Servo Valves
With either
Mechanical or
Electrical
Feedback (spool
position).
Parker Models
Pulsar VP,
VPLs.
DF**, ERVs
D*FWs, D*FTs’
D*FXs’
D*FH
D*FMs
D*1FH
BDs’
DYs’
SEs’
Mechanical
Construction
(spool shift)
Electro-Hydraulic
Pilot,
Mechanical
(spring) Return
Electromagnetic
Force,
Mechanical
(spring) Return
Electromagnetic
Force,
Mechanical
(spring) Return
Electromagnetic
Force, Mechanical
(spring) Return
Torque Motor Pilot
Control
Balance PSI spool
Control
Hysteresis
3…..7%
3…7%
0.03…..1%
0.1….5%
0.1…..0.5%
Frequency
Response
< 10 Hz
10…50 Hz
10….70 Hz
50...150 Hz
100…200 Hz
Center Lap
Condition
Overlap 5…20%
Zero Overlap
Zero Overlap
Operating
Pressures Limits
(Drop across
metering edge).
1000…2000 PSI
1000…3000 PSI
None
Closed Loop
Position & Force
Closed Loop
Position & Force
Applications
73
Open Loop Control
Low End Closed
Loop Position
Actuators
Rotary Motion
•Position Control (Angle)
•Velocity
•Torque
Linear Motion
•Position Control
•Velocity
•Force
74
Actuators Linear Feedback Types
Magnetostrictive (M.D.T.s)
Pulse is sent down waveguide, when
hits magnet, “twist” is sensed. Time
between pulse sent to twist measured
dictates distance.
Approximately 9 microseconds = 1”
75
Actuators Linear Feedback Types
Magnetostrictive (M.D.T.s)
Analog Outputs
SSI Output
Digital Outputs
76
Valve Drivers and Motion Controllers
77
Valve Drivers (Open Loop) Off Board
Elec
Optional
Set point card
•
•
•
78
Converts “Command Signal” to
PWM signal to drive Coil.
Digital Versions (shown)
incorporate a microprocessor
with numeric settings.
Analog Versions incorporate
Trim pots for
Valve Drivers (Open Loop) Off Board
Elec
79
Valve Drivers (Closed Loop)
80
Valve Drivers (Closed Loop)
81
Motion Controllers
Actual
Position
-
Position
Error
Σ
Proportional
G ain
+
Accumulator
(Inte grator)
Targe t
Position
∆ Error
(Diffe re ntiator)
∆ Position
(Ve locity)
Targe t
G e ne rator
Command
Proce ssor
Ladde r
Logic
∆ Ve locity
(Acce le ration)
Inte gral
G ain
Diffe re ntial
G ain
Fe e d
Forward
Acce l Fe e d
Forward
Position
De adband
Eliminator
RmcWin
PLC
“Generate A Target Profile”
82
Σ
Drive
O utput
Velocity
Velocity and Accel Feed Forward
Actual
Position
-
Position
Error
Σ
Proportional
G ain
+
Accumulator
(Inte grator)
Targe t
Position
∆ Error
Target(Diffe
Velocity
re ntiator)
Target Position
∆ Position
(Ve locity)
Targe t
G e ne rator
∆ Ve locity
(Acce le ration)
Command
Proce ssor
Ladde r
Logic
Diffe re ntial
Velocity
G ain FFWD Drive Σ
Drive
O utput
Fe e d
Forward
Acce l Fe e d
Forward
De adband
Eliminator
RmcWin
Target Acceleration
83
Inte gral
G ain
Accel FFWD Drive
DRIVE
Proportional Gain ONLY
0.625” Following Error
84
Feed Forward Adjust “F” Cmd
Correct drive for
constant velocity
portion of move.
85
Position Error during
Accel/Decel
Brake
Accel FFWD corrects for
error during Accel/Decel
Boost
86
Proper Velocity and Accel Feed
forwards.
87
Real Time Plot Data
Actual
Velocity
Actual
Position
Voltage to
Servo Valve
88
Closed Loop Position System
Control Drive
Signal from the
Motion Control
Module
Metal Tubing
Valve
Manifold
Magnet
MDT
Position
Transducers
Pump
Reservoir
89
Principle of Operation Force Balance
90
Balanced Force
Fa=Pa*Area a
91
Fb=Pb*Area b
Principle of operation (cont)
Valve null = net
forces across
cylinder equal
zero
92
Closed Loop Force Control
Control Drive
Signal from the
Motion Control
Module
Metal Tubing
Valve
Manifold
Magnet
MDT
Differential
Pressure
Transducers
Pump
Reservoir
93
or
Load Cell
Balanced Force
Fa=Pa*Area a
94
Fb=Pb*Area b
Force Control
Decompression
Start Force Control
Increased Force
With different
Ramp Rate
In Position Control
Maintained
Force for X
amount of Time
95
Back into
Position Control
Thank you!
96

Introduction to Electro-hydraulic Proportional and Servo

Transcription

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