brucebesch-introelectrohydraulic

7/14/2019 BruceBesch-IntroElectrohydraulic

1/96

Introduction to Electro-hydraulic

Proportional and Servo Valves

1


2/96

Servo Valves

With either

Mechanical or

Electrical

Feedback (spool

position).

Servo

Performance,

Closed Loop

Valves with Spool

Position Feedback

NFPA Mounting

With Spool

Position

Feedback

NFPA Mounting

Without Spool

Position

Feedback

Mobile bankable

Style, Threaded

Cartrdige Style

BDsDYs

SEs

D*FPD*FHs

D*1FH

D*FXsD*FWs, D*FTsPulsar VP,VPLs.

Parker Models

Closed Loop

Position & Force

Closed Loop

Position & Force

Low End Closed

Loop Position

Open Loop ControlApplications

None10003000 PSI10002000 PSIOperating

Pressures Limits

(Drop across

metering edge).

Zero OverlapZero OverlapOverlap 520%Center Lap

Condition

100200 Hz50...150 Hz10.70 Hz1050 Hz< 10 HzFrequency

Response

0.1..0.5%0.1.5%0.03..1%37%3..7%Hysteresis

Torque Motor Pilot

Control

Balance PSI spool

Control

Electromagnetic

Force, Mechanical

(spring) Return

Electromagnetic

Force,

Mechanical

(spring) Return

Electromagnetic

Force,

Mechanical

(spring) Return

Electro-Hydraulic

Pilot,

Mechanical

(spring) Return

Mechanical

Construction

(spool shift)

Servo

ValvesProportional Valves

2


3/96

Meter Out Circuit

Free flow into the cap endMetered Flow out the head

end.

PT T

A B

P to A

B to T

3


4/96

Meter Out Circuit

Free flow into the cap endMetered Flow out the head

end.

PT T

A B

P to B

A to T

4


5/96

Electrohydraulic Valves

PT T

Shift Spool slightly to createmetering Orifice

P to A

B to T

A B

5


6/96

Servo Valves

With either

Mechanical or

Electrical

Feedback (spool

position).

Servo

Performance,

Closed Loop

Valves with Spool

Position Feedback

NFPA Mounting

With Spool

Position

Feedback

NFPA Mounting

Without Spool

Position

Feedback

Mobile bankable

Style, Threaded

Cartridge Style

BDsDYs

SEs

D*FPD*FHs

D*1FH


Parker Models

Closed Loop

Position & Force

Closed Loop

Position & Force

Low End Closed

Loop Position



Pressures Limits

(Drop across

metering edge).


Condition


Response

0.1..0.5%0.1.5%0.03..1%37%3..7%Hysteresis

Torque Motor Pilot

Control

Balance PSI spool

Control

Electromagnetic

Force, Mechanical

(spring) Return

Electromagnetic

Force,

Mechanical

(spring) Return

Electromagnetic

Force,

Mechanical

(spring) Return

Electro-Hydraulic

Pilot,

Mechanical

(spring) Return

Mechanical

Construction

(spool shift)

Servo


6


7/96

1C2C

PT

Limiter

Compensator

Sectional ValvesSectional Valves

VPL SeriesVPL Series

7


8/96

Optional

L.S. Port

C2

Pressure

Limiter

Flow

Limiters

Anti-Cav. CheckCyl. ReliefPulsar

Solenoid

Manual

Override

Individual

Compensator

C1

Pressure

Limiter


VPL SeriesVPL Series

8


9/96


VPL SeriesVPL Series (C1 Energized)

9


10/96

VPL Main Spool8 Flow Rates (1.3, 2.5, 4, 7, 11, 17, 24, 30 GPM)

Centering Spring

Meter-In Lands

Meter-Out Lands

OCM

VOC

CC

200 or 350 PSI

Detent & Friction-Lock also Available

SpoolMarking

Ex. 524

Regenative

Options

10


11/96

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


12/96

VPL Compensator

Components

3 Sizes

of Shims

(.003 .008 .025 )

12


13/96

Servo Valves

With either

Mechanical or

Electrical

Feedback (spool

position).

Servo

Performance,

Closed Loop

Valves with Spool

Position Feedback

NFPA Mounting

With Spool

Position

Feedback

NFPA Mounting

Without Spool

Position

Feedback

Mobile bankable

Style, Threaded

Cartridge Style

BDsDYs

SEs

D*FPD*FHs

D*1FH


Parker Models

Closed Loop

Position & Force

Closed Loop

Position & Force

Low End Closed

Loop Position



Pressures Limits

(Drop across

metering edge).


Condition


Response

0.1..0.5%0.1.5%0.03..1%37%3..7%Hysteresis

Torque Motor Pilot

Control

Balance PSI spool

Control

Electromagnetic

Force, Mechanical

(spring) Return

Electromagnetic

Force,

Mechanical

(spring) Return

Electromagnetic

Force,

Mechanical

(spring) Return

Electro-Hydraulic

Pilot,

Mechanical

(spring) Return

Mechanical

Construction

(spool shift)

Servo


13


14/96

How does it Work? (No Spool Feedback)

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.

Solenoid A

Solenoid B

Integrated Electronics

(PWD Amplifier)

14


15/96

WindingWinding

PlungerPlunger

(armature)(armature)

Push pinPush pin

FrameFrame

How does it Work?Proportional Solenoid Construction

15


16/96

How does it Work?Solenoid Operation

.

.5 VDC 50%

16


17/96

C Notch Spool

V-Notch Spool

Proportional Valve Spool

Designs

17


18/96

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 8 100

SPOOL SHIFT, %

FLOWAR

EA%

0

10

20

3040

50

60

70

80

90

100

0 20 40 60 8 100SPOOL SHIFT, %

FLOW

AREA%

P-A-B-T = 145 PSI

P-A-B-T = 145 PSI

Proportional Valve Spool

Designs

18


19/96

V-Notch - Bleed Center

bleed notch

primary

meteringnotch

19


20/96

Proportional Valve DeadbandPs

A B

T T

20


21/96

Mechanical Spool

Overlap (Deadband)

+ Q

I+-

Positive Overlap + Spring Force

21


22/96

Deadband Eliminator

-

+

K100

Vout

inV-+

K100

K100

-

+

K100

DBE+

K100

DBE

K100

CCV+

CCV

ss+

22


23/96

Deadband

Compensation

+ Q

I+

-

Deadband Compensation

23


24/96

Deadband Over

Compensated

+ Q

I+

-

Deadband Compensation

24


25/96

Valve Drivers (Open Loop) On Board

Integrated Electronics

25


26/96

Ramp Pots

Max Pots

MIN Pots

Valve Drivers (Open Loop) On BoardIntegrated Electronics (Pot adjustments)

26


27/96

Digital Onboard Electronics

D1FB*0 OBE

Valve Drivers (Open Loop) On Board

Integrated Electronics (PC Adjustments)

27


28/96

Deadband Eliminator P to A flow PathPs

A B

T T

28


29/96

Deadband Eliminator (P to B flow Path)Ps

A B

T T

29


30/96

Servo ValvesWith either

Mechanical or

Electrical

Feedback (spool

position).

ServoPerformance,

Closed Loop

Valves with Spool

Position Feedback

NFPA MountingWith Spool

Position

Feedback

NFPA MountingWithout Spool

Position

Feedback

Mobile bankableStyle, Threaded

Cartrdige Style

BDs

DYs

SEs

D*FH

D*FMs

D*1FH

D*FXsD*FWs, D*FTsPulsar VP,

VPLs.DF**, ERVs

Parker Models

Closed Loop

Position & Force

Closed Loop

Position & Force

Low End Closed

Loop Position



Pressures Limits

(Drop across

metering edge).


Condition


Response

0.1..0.5%0.1.5%0.03..1%37%3..7%Hysteresis

Torque Motor Pilot

Control

Balance PSI spool

Control

Electromagnetic

Force, Mechanical

(spring) Return

Electromagnetic

Force,

Mechanical

(spring) Return

Electromagnetic

Force,

Mechanical

(spring) Return

Electro-Hydraulic

Pilot,

Mechanical

(spring) Return

Mechanical

Construction

(spool shift)

Servo


30


31/96

Spool Feedback, How does it Work?

Solenoid ASolenoid B

Spool Position LVDT Integrated Electronics

(PWD Amplifier)

Same basic operation as non-feedback valves, but

outcome is measured and corrected to match desiredresult.

Closing the Loop.

31


32/96

Spool Feedback DeviceLinear Variable Differential Transformer

Primary

Secondary Secondary

Oscillator

Demodulator

Input

Output

Core

V DC

V DC

Spool

32


33/96

L.V.D.T.s

33


34/96

LVDT

CMD + Error I F

X

FB-

A

Disturbances

adj

Spool Feedback Devices(Electrical Schematic-IntegratedElectronics)

34


35/96

Command

Signal

u s

Valve position feedback

Force

Internal Closed Loop

35


36/96

Sample Application

36


37/96

Kv Sizing

37


38/96

Non-Symmetrical Spools

38


39/96

Sample Application, Number 2

39


40/96

(P-A-B-T = 145 PSI)

-10

-7.5

-5

-2.5

0

2.5

5

7.5

10

-10 -7.5 -5 -2.5 0 2.5 5 7.5 10

Valve Command, Volts

FlowR

ate,

GPM

Non-Symmetrical Spools

40


41/96

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 62 notches instead of 6

41


42/96

Non-symmetrical Spools

holes7.1

holes85.holes7.1

holes85.

SP

A B

P T

A B

T

42


43/96

Sample Application No. 2 with Non-

Symmetrical Spool

43


44/96

Flow

X

Flow Force Effects Proportional

Valves

44


45/96

Flow Force Performance

Operating Limits

Curves show Valve

Performance over

entire Pressure

Range

45

ServoP ti l V l


46/96


Mechanical or

Electrical

Feedback (spool

position).

ServoPerformance,

Closed Loop

Valves with Spool

Position Feedback


Position

Feedback


Position

Feedback


Cartrdige Style

BDs

DYsSEs

D*FH

D*FMsD*1FH


VPLs.DF**, ERVs

Parker Models

Closed Loop

Position & Force

Closed Loop

Position & Force

Low End Closed

Loop Position



Pressures Limits

(Drop across

metering edge).


Condition


Response

0.1..0.5%0.1.5%0.03..1%37%3..7%Hysteresis

Torque Motor Pilot

Control

Balance PSI spool

Control

Electromagnetic

Force, Mechanical

(spring) Return

Electromagnetic

Force,

Mechanical

(spring) Return

Electromagnetic

Force,

Mechanical

(spring) Return

Electro-Hydraulic

Pilot,

Mechanical

(spring) Return

Mechanical

Construction

(spool shift)


46


47/96

D1FP (NG6) valve as pilot valve for D*1FP

integrated driveelectronics

Voice Coil Drive VCD

valve body

spool-sleeve

assembly

spring assembly

fail-safe position

VCDMilestone for High

Performance Valves

47


48/96

Parker Voice Coil Drive (VCD) technology for

highest precisionpermanent

magnet

coil

carriage housing

integrated feedback

system

pushpin

VCDMilestone for

High Performance Valves

48

VCD Mil f Hi h


49/96

VCD principle, moved coil in magnetic field

Fo= B. I . l

-Fo X

Fo

B = magnetic flux density

I = electrical current

l = wire length (winding)

N S

winding

permanent magnet

iron (magnetic)

non-magnetic material

X


Performance Valves

49

VCD Mil t f Hi h


50/96

Characteristics of force in comparison

F[N]

x [mm]

F [N]

x [mm]0 0conventional solenoid

force dependent of stroke


Performance Valves

Voice Coil Drive

force independent of stroke

50

S S l id/V i C il V l


51/96

Ps

A B

T T

HousingSleeve

Servo Solenoid/Voice Coil Valves

No DeadbandLine to Line LapOr Axis Cut

51

S l d Sl A t


52/96

Spool and Sleeve Arrangement

52

Spool Lap Conditions


53/96


(Positive) Overlap

Zerolap

(Negative) Underlap

53



54/96


(Positive) Overlap Zerolap

U = 40% U = 40%

U = 20% U = 20%

U = 0% U = 0%

54

Flow windows


55/96

Flow windows

Standard Symmetrical Laps

Knick Servo Cuts

55

Servo



56/96


Mechanical or

Electrical

Feedback (spool

position).

ServoPerformance,

Closed Loop

Valves with Spool

Position Feedback


Position

Feedback


Position

Feedback


Cartrdige Style

BDs

DYs

SEs

D*FH

D*FMs

D*1FH


VPLs.DF**, ERVs

Parker Models

Closed Loop

Position & Force

Closed Loop

Position & Force

Low End Closed

Loop Position



Pressures Limits

(Drop across

metering edge).


Condition


Response

0.1..0.5%0.1.5%0.03..1%37%3..7%Hysteresis

Torque Motor Pilot

Control

Balance PSI spool

Control

Electromagnetic

Force, Mechanical

(spring) Return

Electromagnetic

Force,

Mechanical

(spring) Return

Electromagnetic

Force,

Mechanical

(spring) Return

Electro-Hydraulic

Pilot,

Mechanical

(spring) Return

Mechanical

Construction

(spool shift)

Valves

56

Servo Valve Double Flapper Design


57/96


Torque Motor

Spool & Sleeve

Assembly

Feedback Spring

57

S V l


58/96


Flexure Tube

N

S

N

S

FrameCoil Coil

Flapper

Armature

Feedback Spring

and Ball/Ruby

Nozzle

58

Servo Valve Principles of Operation


59/96

N

S

N

S

PP

P P

RR

A B

Servo Valve - Principles of Operation

Valve at Null

59



60/96

N

S

N

S

P

P P

R

A B

P R

(-)

(+)


Valve With Current Applied

60

Flow Forces Not an Issue with Servo


61/96

Flow Forces Not an Issue with Servo

Valves

61

Servo s Performances


62/96

Servo s Performances

62

Symbology


63/96

Proportional Directional Valve

u s

Proportional Valve with Spool

Feedback

u s

Servo Performance Proportional Valve

Symbology

Servo Valve

63


64/96

Terminologies

64

Pressure Gain


65/96

80% rise

2% command

40% pressure change

1% command change

Pressure Gain

65

Hysteresis


66/96

y

%ofFullOpenFlow

Input Signal

Mechanical

Spool

Overlap: the

DeadbandIncreasing Flow

from Valve

Decreasing Flow

from Valve

Hysteresis

0%

10%

20%

30%

40%

50%

60%

70%80%

90%

100%

1 2 3 4 5 6 7 8 9 10

66

Repeatability


67/96

p y

%ofFullOpenFlow

Input Signal

IncreasingFlow

Only

Repeatability

0%

10%

20%

30%

40%

50%

60%

70%80%

90%

100%

1 2 3 4 5 6 7 8 9 10

67

Valve Frequency


68/96

q y

Two methods: frequency response, step

response (well use frequency response)

offset

bias

CMD

Q

Bias or one sided

CMD

Q

Thru center

68

Valve Frequency Response


69/96

CMD

FB

0 Phase Lag

Valve

90 Phase Lag

The input frequency which creates a phase lag of 90 is the

defining characteristics of a valve and is referred to as

bandwidth

90 Phase Lag = cycle

Valve Frequency Response

69

Frequency Response


70/96

q y p

To measure the response of a control

valve, a sinusoidal varying input signal isapplied, 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 valvebecomes less able to follow the input

signal precisely

70

Frequency Response


71/96

The output starts to lag behind the input,

then the valve is not able to reach themaximum output position before the input

signal reverses

The lag between the input and output isknown as phase lag

The reduced output apparent at higherfrequencies is known as attenuation

71

Valve Frequency


72/96

Frequency response (sine wave) to make catalog data

72

Servo



73/96

Servo Valves

With either

Mechanical or

Electrical

Feedback (spool

position).

Servo

Performance,

Closed Loop

Valves with Spool

Position Feedback

NFPA Mounting

With Spool

Position

Feedback

NFPA Mounting

Without Spool

Position

Feedback

Mobile bankable

Style, Threaded

Cartrdige Style

BDs

DYsSEs

D*FH

D*FMsD*1FH


VPLs.DF**, ERVs

Parker Models

Closed Loop

Position & Force

Closed Loop

Position & Force

Low End Closed

Loop Position



Pressures Limits

(Drop across

metering edge).


Condition


Response

0.1..0.5%0.1.5%0.03..1%37%3..7%Hysteresis

Torque Motor Pilot

Control

Balance PSI spool

Control

Electromagnetic

Force, Mechanical

(spring) Return

Electromagnetic

Force,

Mechanical

(spring) Return

Electromagnetic

Force,

Mechanical

(spring) Return

Electro-Hydraulic

Pilot,

Mechanical

(spring) Return

Mechanical

Construction

(spool shift)

73

Actuators


74/96

Linear Motion

Position Control

Velocity

Force

Rotary Motion

Position Control (Angle)Velocity

Torque

74

Actuators Linear Feedback Types


75/96

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


76/96

Magnetostrictive (M.D.T.s)

Analog Outputs

Digital Outputs

SSI Output

76

Valve Drivers and Motion Controllers


77/96

77

Valve Drivers (Open Loop) Off Board


78/96

Elec

Converts Command Signal to

PWM signal to drive Coil.

Digital Versions (shown)

incorporate a microprocessorwith numeric settings.

Analog Versions incorporate

Trim pots for

Optional

Set point card

78

Valve Drivers (Open Loop) Off Board


79/96

Elec

79

Valve Drivers (Closed Loop)


80/96

80

Valve Drivers (Closed Loop)


81/96

81

Motion Controllers


82/96

ActualPosition

PositionError Proportional

Gain

Accumulator(Integrator)

Error(Differentiator)

IntegralGain

DifferentialGain

FeedForward

Forward

Position(Velocity)

+

-

DriveOutput

Target

Generator

Target

Position

CommandProcessor

LadderLogic RmcWin

Accel Fee dVelocity(Acceleration)

DeadbandEliminator

Velocity

Position

Generate A Target Profile

PLC

82

Velocity and Accel Feed ForwardPosition


83/96

ActualPosition

Error ProportionalGain

Accumulator(Integrator)

Error(Differentiator)

IntegralGain

Differential

Gain

FeedForward

Forward

Position(Velocity)

+

-

DriveOutput

Target

Generator

TargetPosition

CommandProcessor

LadderLogic RmcWin

Accel Fee dVelocity (Acceleration)

DeadbandEliminator

Target Position Target VelocityVelocity FFWD Drive

Target Acceleration Accel FFWD Drive

DRIVE

83

Proportional Gain ONLY


84/96

0.625 Following Error

84

Feed Forward Adjust F Cmd


85/96

Correct drive for

constant velocityportion of move.

85

Position Error during


86/96

Accel/Decel

Accel FFWD corrects for

error during Accel/Decel

Boost

Brake

86

Proper Velocity and Accel Feed

f d


87/96

forwards.

87

R l Ti Pl t D t


88/96

Real Time Plot Data

Actual

Position

Actual

Velocity

Voltage to

Servo Valve

88

Closed Loop Position SystemControl Drive

Signal from the


89/96

Reservoir

Metal Tubing

MDT

Magnet

Pump

Valve

Signal from theMotion Control

Module

Manifold

Position

Transducers

89

Principle of Operation Force Balance


90/96

90

Balanced Force


91/96

FbFb==PbPb*Area b*Area bFaFa=Pa*Area a=Pa*Area a

91

Principle of operation (cont)


92/96

Valve null = net

forces across

cylinder equal

zero

92

Closed Loop Force ControlControl Drive



93/96

Reservoir

Metal Tubing

MDT

Magnet

Pump

Valve


Module

Manifold

Differential

Pressure

Transducers

Load Cellor

93

Balanced Force


94/96

FbFb==PbPb*Area b*Area bFaFa=Pa*Area a=Pa*Area a

94

Force Control


95/96

In Position Control

Start Force Control

Maintained

Force for X

amount of Time

Increased Force

With different

Ramp Rate

Decompression

Back into

Position Control

95


96/96

Thank you!

96

brucebesch-introelectrohydraulic

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