EP0251603A2 - Actionneur hydraulique commandé par servo-soupape - Google Patents

Actionneur hydraulique commandé par servo-soupape Download PDF

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Publication number
EP0251603A2
EP0251603A2 EP87305491A EP87305491A EP0251603A2 EP 0251603 A2 EP0251603 A2 EP 0251603A2 EP 87305491 A EP87305491 A EP 87305491A EP 87305491 A EP87305491 A EP 87305491A EP 0251603 A2 EP0251603 A2 EP 0251603A2
Authority
EP
European Patent Office
Prior art keywords
servovalve
hydraulic
actuator
feedback signal
hydraulic system
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP87305491A
Other languages
German (de)
English (en)
Other versions
EP0251603A3 (fr
Inventor
David Allen Williams
Peter Godfrey Wright
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Group Lotus PLC
Original Assignee
Group Lotus PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Group Lotus PLC filed Critical Group Lotus PLC
Publication of EP0251603A2 publication Critical patent/EP0251603A2/fr
Publication of EP0251603A3 publication Critical patent/EP0251603A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/16—Special measures for feedback, e.g. by a follow-up device

Definitions

  • the invention relates to an hydraulic system in which an hydraulic actuator is controlled by a servovalve.
  • the present invention provides, in an hydraulic system having an actuator controlled by a servovalve, means responsive to the actuator movement or to a variable related thereto to provide a feedback signal to the servovalve.
  • the feedback signal can be derived from fluid flow associated with the actuator movement and can be either electrical or hydraulic.
  • the invention can thus provide a system in which an electric feedback signal derived from fluid flow between an electrohydraulic servovalve and an hydraulic actuator, which may be a double acting hydraulic actuator, is fed back to the control of the servovalve, through circuitry by which the signal is modified if required.
  • the feedback signal can instead be an hydraulic signal, which may again be derived from fluid flow between a servovalve and the hydraulic actuator, and which can be applied to the servovalve directly.
  • a restriction can be placed in the fluid flow line and the pressure differential across it can be sensed.
  • the feedback signal can be constituted by the pressure differential as such or by an electrical signal developed from it by suitable transducer means.
  • the invention thus provides simple and convenient means for linearizing actuator velocity relative to a command current signal.
  • the inherent stabilizing effect obtained is of value particularly but not exclusively in active suspension systems for vehicles for example road vehicles.
  • the servovalve apparatus schematically shown in Figure 1 comprises a double-acting hydraulic actuator 1 controlled by an electrohydraulic servovalve 10.
  • the actuator 1 is indicated simply as a piston 2 movable within a cylinder 4 and having piston rods 5 extending from the piston outwardly through the cylinder end walls to provide a mechanical output.
  • the hydraulic actuator may be incorporated for example in an active vehicle suspension system as described in WO 84/02886 and may have a structure as described in WO 85/01919, both of which are incorporated herein by reference.
  • the servovalve 10 comprises a valve spool 11 slidable axially within a cylinder 12 provided with two pressure fluid inlet ports 14 communicating with a source 16 of oil or other hydraulic fluid and longitudinally spaced apart on opposite sides of a central return port 15 leading back to the source.
  • An outlet port 17 is located between each of the inlet ports 14 and the return port 15 and communicates by way of an hydraulic line 19 with a respective end of the actuator cylinder 4.
  • the servovalve spool 11 has three spaced valve portions connected by stem portions and shaped and dimensioned so that the position of the actuator piston 2 is controlled in dependence on the spool.
  • the position of the spool 11 can be adjusted by any suitable means. As shown, the spool position is controlled by fluid pressure from the fluid pressure source 16 or another such source applied to the outer ends of the spool under control of a torque motor 20 with mechanical spool position feedback by way of a spring wire 21.
  • the torque motor 20 is under control of control system circuitry or logic 25 which may be an analogue, digital or hybrid system and which provides a valve drive current proportional to the required actuator velocity.
  • the actual velocity response of the actuator 1 depends on such factors as its loading, upon the fluid pressure within the system, on friction, and compliance between the servovalve 10 and the piston 2. It is desirable to linearise the actuator velocity relative to the demand current and in accordance with the invention, provision is made for a velocity feedback signal to the servovalve 10, realized in the present embodiment in the form of an electric signal applied to the torque motor 20.
  • a restriction or orifice 30 is provided in one or other of the lines 19 between the servovalve 10 and the actuator 1, so that a pressure differential is generated across it during movement of the hydraulic fluid, which pressure differential is proportional to the square of the fluid velocity, with a sign dependent on the direction of flow.
  • the pressure differential is sensed by pressure transducers 31, exposed to the fluid pressures at opposed sides of the orifice 30 by way of side tube connections 32.
  • the transducer outputs representing the pressure differential are treated by suitable circuitry or logic, which may be incorporated in the control system circuitry 25, so as to generate a control signal for the torque motor 20 which is proportional to the velocity, whereby an inherently stabilizing control effect for the servovalve is achieved.
  • modified servovalve 50 has chambers 51 formed at respective ends of a servovalve cylinder 52, in which are slidingly received working pistons 56 on end extensions of the valve spool 55.
  • the side tube connections 32 extend from opposed sides of the orifice 30 to these chambers 51.
  • the apparatus of Figure 2 is thus an hydraulic analogue of the electrical apparatus described with reference to Figure 1, and does not need the transducers 31 of that apparatus or the related circuitry.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Servomotors (AREA)
  • Fluid-Pressure Circuits (AREA)
EP87305491A 1986-06-24 1987-06-22 Actionneur hydraulique commandé par servo-soupape Withdrawn EP0251603A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8615427 1986-06-24
GB868615427A GB8615427D0 (en) 1986-06-24 1986-06-24 Servovalves

Publications (2)

Publication Number Publication Date
EP0251603A2 true EP0251603A2 (fr) 1988-01-07
EP0251603A3 EP0251603A3 (fr) 1989-12-06

Family

ID=10600030

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87305491A Withdrawn EP0251603A3 (fr) 1986-06-24 1987-06-22 Actionneur hydraulique commandé par servo-soupape

Country Status (5)

Country Link
EP (1) EP0251603A3 (fr)
JP (1) JPS6323006A (fr)
KR (1) KR880000705A (fr)
AU (1) AU7456087A (fr)
GB (1) GB8615427D0 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5232242A (en) * 1991-06-18 1993-08-03 Ford Motor Company Power consumption limiting means for an active suspension system
WO2012095561A2 (fr) * 2011-01-14 2012-07-19 Parker Hannifin Manufacturing Finland Oy Distributeur équipé d'une compensation de pression

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3126031A (en) * 1964-03-24 hayner
GB1335042A (en) * 1970-01-05 1973-10-24 Sperry Rand Ltd Hydraulic actuator controls
DE2447858A1 (de) * 1973-10-10 1975-04-17 Sperry Rand Ltd Vorrichtung zur steuerung einer fluessigkeitsstroemung
EP0021742A2 (fr) * 1979-06-15 1981-01-07 Sperry Corporation Dispositif de commande de vérins hydrauliques
GB2105881A (en) * 1981-08-21 1983-03-30 Sperry Corp Feedback controlled hydraulic valve system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3126031A (en) * 1964-03-24 hayner
GB1335042A (en) * 1970-01-05 1973-10-24 Sperry Rand Ltd Hydraulic actuator controls
DE2447858A1 (de) * 1973-10-10 1975-04-17 Sperry Rand Ltd Vorrichtung zur steuerung einer fluessigkeitsstroemung
EP0021742A2 (fr) * 1979-06-15 1981-01-07 Sperry Corporation Dispositif de commande de vérins hydrauliques
GB2105881A (en) * 1981-08-21 1983-03-30 Sperry Corp Feedback controlled hydraulic valve system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5232242A (en) * 1991-06-18 1993-08-03 Ford Motor Company Power consumption limiting means for an active suspension system
WO2012095561A2 (fr) * 2011-01-14 2012-07-19 Parker Hannifin Manufacturing Finland Oy Distributeur équipé d'une compensation de pression
WO2012095561A3 (fr) * 2011-01-14 2014-01-16 Parker Hannifin Manufacturing Finland Oy Distributeur équipé d'une compensation de pression
US9140274B2 (en) 2011-01-14 2015-09-22 Parker Hannifin Manufacturing Finland Oy Directional valve equipped with pressure compensation

Also Published As

Publication number Publication date
EP0251603A3 (fr) 1989-12-06
AU7456087A (en) 1988-01-07
JPS6323006A (ja) 1988-01-30
GB8615427D0 (en) 1986-07-30
KR880000705A (ko) 1988-03-28

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Inventor name: WRIGHT, PETER GODFREY

Inventor name: WILLIAMS, DAVID ALLEN