JP5232177B2 - 作動装置を能動的および受動的に作動させる対立する流体制御システム - Google Patents

作動装置を能動的および受動的に作動させる対立する流体制御システム Download PDF

Info

Publication number
JP5232177B2
JP5232177B2 JP2009551856A JP2009551856A JP5232177B2 JP 5232177 B2 JP5232177 B2 JP 5232177B2 JP 2009551856 A JP2009551856 A JP 2009551856A JP 2009551856 A JP2009551856 A JP 2009551856A JP 5232177 B2 JP5232177 B2 JP 5232177B2
Authority
JP
Japan
Prior art keywords
pressure
load
return
spool
fluid
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.)
Expired - Fee Related
Application number
JP2009551856A
Other languages
English (en)
Japanese (ja)
Other versions
JP2010520418A5 (enExample
JP2010520418A (ja
Inventor
ヤコブセン,スティーヴン・シー
オリビエ,マーク
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.)
Raytheon Co
Original Assignee
Raytheon Co
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 Raytheon Co filed Critical Raytheon Co
Publication of JP2010520418A publication Critical patent/JP2010520418A/ja
Publication of JP2010520418A5 publication Critical patent/JP2010520418A5/ja
Application granted granted Critical
Publication of JP5232177B2 publication Critical patent/JP5232177B2/ja
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/04Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F15B13/0401Valve members; Fluid interconnections therefor
    • F15B13/0402Valve members; Fluid interconnections therefor for linearly sliding valves, e.g. spool valves
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/006Hydraulic "Wheatstone bridge" circuits, i.e. with four nodes, P-A-T-B, and on-off or proportional valves in each link
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00Circuits for servomotor systems
    • F15B2211/30Directional control
    • F15B2211/305Directional control characterised by the type of valves
    • F15B2211/3056Assemblies of multiple valves
    • F15B2211/30565Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00Circuits for servomotor systems
    • F15B2211/30Directional control
    • F15B2211/305Directional control characterised by the type of valves
    • F15B2211/3056Assemblies of multiple valves
    • F15B2211/30565Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve
    • F15B2211/30575Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve in a Wheatstone Bridge arrangement (also half bridges)
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00Circuits for servomotor systems
    • F15B2211/30Directional control
    • F15B2211/32Directional control characterised by the type of actuation
    • F15B2211/329Directional control characterised by the type of actuation actuated by fluid pressure
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00Circuits for servomotor systems
    • F15B2211/30Directional control
    • F15B2211/35Directional control combined with flow control
    • F15B2211/351Flow control by regulating means in feed line, i.e. meter-in control
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00Circuits for servomotor systems
    • F15B2211/70Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051Linear output members
    • F15B2211/7053Double-acting output members

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Fluid-Driven Valves (AREA)
  • Multiple-Way Valves (AREA)
JP2009551856A 2007-02-28 2008-02-28 作動装置を能動的および受動的に作動させる対立する流体制御システム Expired - Fee Related JP5232177B2 (ja)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US90424507P 2007-02-28 2007-02-28
US60/904,245 2007-02-28
PCT/US2008/055347 WO2008106611A1 (en) 2007-02-28 2008-02-28 Antagonistic fluid control system for active and passive actuator operation

Publications (3)

Publication Number Publication Date
JP2010520418A JP2010520418A (ja) 2010-06-10
JP2010520418A5 JP2010520418A5 (enExample) 2011-04-28
JP5232177B2 true JP5232177B2 (ja) 2013-07-10

Family

ID=39473304

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2009551856A Expired - Fee Related JP5232177B2 (ja) 2007-02-28 2008-02-28 作動装置を能動的および受動的に作動させる対立する流体制御システム

Country Status (4)

Country Link
US (1) US8061261B2 (enExample)
EP (1) EP2122185A1 (enExample)
JP (1) JP5232177B2 (enExample)
WO (1) WO2008106611A1 (enExample)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5460335B2 (ja) 2007-02-28 2014-04-02 レイセオン カンパニー 選択的に起動可能な作動装置を有する流体制御システム
DE102012017714A1 (de) * 2012-09-07 2014-03-13 Hoerbiger Automatisierungstechnik Holding Gmbh Geregelte Proportional-Dreiwegeventileinheit
FI128135B (fi) * 2017-10-20 2019-10-31 Pneumaxpert Oy Oskillointisylinterijärjestely
US12392361B1 (en) 2024-04-29 2025-08-19 Hamilton Sunstrand Corporation Cross-bleed safety mechanism for a linear hydraulic actuator

Family Cites Families (87)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US204828A (en) 1878-06-11 Improvement
US2861550A (en) 1952-10-28 1958-11-25 Westinghouse Electric Corp Hydraulic power control valve
FR1104952A (fr) 1954-05-19 1955-11-25 Rech Etudes Production Sarl Moteur à fluide, sans jeu
DE1053462B (de) 1958-02-13 1959-03-26 Wagner & Co Werkzeugmaschinenf OElhydraulische Blechbiegepresse fuer lange Traeger u. dgl.
GB997756A (en) 1964-06-22 1965-07-07 Daimler Benz Ag Improvements relating to hydraulic servo devices on motor vehicles
FR1524697A (fr) * 1966-07-06 1968-05-10 Hydraulic Unit Specialities Co Mécanisme de soupape de commande
US3583422A (en) 1967-10-19 1971-06-08 Zahnradfabrik Friedrichshafen Valve construction for controlled pressure buildup in fluid-operated brake or clutch
DE1916266A1 (de) 1968-05-21 1970-10-08 Bbc Brown Boveri & Cie Elektrohydraulisches Stellgeraet
GB1214947A (en) 1968-08-17 1970-12-09 Girling Ltd Fluid pressure control valve
US3566919A (en) 1969-01-24 1971-03-02 Pneumo Dynamics Corp Hydraulic servo valve with pressure feedback
GB1245662A (en) 1969-03-31 1971-09-08 Aida Tekkosho Kk An article transfer apparatus
BE789975A (fr) 1971-10-12 1973-02-01 Sanders Associates Inc Valve de controle de pression et de debit
JPS5252260Y2 (enExample) * 1972-03-21 1977-11-28
DE2242022C3 (de) 1972-08-26 1980-11-20 Integral Hydraulik & Co, 4000 Duesseldorf Druckmittelfolgesteuerung für Servolenkungen o.dgl
US4069843A (en) 1973-04-02 1978-01-24 International Harvester Company Clutch cylinder circuit and charging valve therefor
US3894712A (en) 1973-07-06 1975-07-15 Parker Hannifin Corp Excess flow servo valve
JPS5060615A (enExample) 1973-09-28 1975-05-24
US3882551A (en) 1974-01-09 1975-05-13 Battelle Memorial Institute Artificial muscle
US4067357A (en) 1974-06-14 1978-01-10 Herion-Werke Kg Pilot-operated directional control valve
DE2642804C2 (de) 1976-09-23 1982-12-23 Daimler-Benz Ag, 7000 Stuttgart Automatisches Gangwechselgetriebe mit einem Sekundär-Servokraftgenerator für die Notversorgung von mit Servokraft arbeitenden Aggregaten der Getriebesteuerung und -schaltung
DE2654366C2 (de) 1976-12-01 1984-08-23 Gebr. Claas, 4834 Harsewinkel Hydroventileinrichtung
DE2710001A1 (de) 1977-03-08 1978-09-14 Daimler Benz Ag Druckentlastungsventil fuer den arbeitsdruck einer servolenkung
US4211147A (en) 1977-06-30 1980-07-08 International Business Machines Corporation Servo-control valve for a linear hydraulic motor
US4131130A (en) 1977-07-18 1978-12-26 Sperry Rand Corporation Pneumatic pressure control valve
US4142612A (en) 1977-09-21 1979-03-06 General Motors Corporation Servo motor with differential pressure controlled and actuated release valve
US4203465A (en) 1979-03-27 1980-05-20 General Motors Corporation Precision pressure control valve
WO1981000600A1 (en) 1979-08-30 1981-03-05 Caterpillar Tractor Co Lock valve with variable length piston and hydraulic system for a work implement using the same
US4348159A (en) 1980-01-07 1982-09-07 Rexnord Inc. Convertible pump servo-valve control
US4362018A (en) 1980-06-12 1982-12-07 Kobe Steel, Ltd. Hydraulic rotation control circuit
JPS57144344A (en) 1981-03-02 1982-09-06 Hitachi Constr Mach Co Ltd Flushing valve
DE3114437C2 (de) 1981-04-09 1989-10-12 Mannesmann Rexroth GmbH, 8770 Lohr Druckregelventil
US4422293A (en) 1981-06-12 1983-12-27 The Bendix Corporation Closed-center hydraulic servo apparatus
ZA825477B (en) 1981-08-21 1983-06-29 Sperry Corp Hydraulic control system
AU565950B2 (en) 1982-01-16 1987-10-01 Ebara Corporation Pressure control valve and oil supply device using said valve
FR2525292B1 (fr) * 1982-04-19 1986-12-19 Chatelin Jacques Servo-moteur hydraulique
US4602481A (en) 1983-09-26 1986-07-29 The Boeing Company Fluid actuator for binary selection of output force
US4714459A (en) 1985-12-23 1987-12-22 Cordis Corporation Three stage intracranial pressure control valve
FR2593265B1 (fr) 1986-01-17 1988-04-22 Rexroth Sigma Distributeur de fluide hydraulique sous pression
US4674539A (en) 1986-02-20 1987-06-23 Sloate Harry M Rotary servo valve
US4657042A (en) 1986-04-07 1987-04-14 Snap-Tite, Inc. Pressure modulation device for hydraulic systems
GB2192941B (en) * 1986-07-25 1990-10-03 Rolls Royce Plc A variable area aircraft air intake
JP2662950B2 (ja) 1986-12-17 1997-10-15 富士重工業株式会社 油圧制御装置
US4774976A (en) 1987-09-23 1988-10-04 Applied Power Inc. Modulating hydraulic pressure control valve and assembly method therefor
JPH0168982U (enExample) 1987-10-26 1989-05-08
JPH0241874U (enExample) 1988-09-14 1990-03-22
JPH0454352Y2 (enExample) 1989-08-29 1992-12-21
US4941508A (en) 1989-12-28 1990-07-17 Dana Corporation Force balanced hydraulic spool valve
GB2240609B (en) 1990-02-02 1993-11-24 Ferranti Int Plc Fluid control valve
US5011180A (en) 1990-02-02 1991-04-30 The University Of British Columbia Digital suspension system
US5103866A (en) 1991-02-22 1992-04-14 Foster Raymond K Poppet valve and valve assemblies utilizing same
JPH0599316A (ja) 1991-10-07 1993-04-20 Toyota Motor Corp 自動変速機の変速制御装置
US5282460A (en) 1992-01-06 1994-02-01 Joyce Ann Boldt Three axis mechanical joint for a power assist device
US5317953A (en) 1992-05-26 1994-06-07 Earth Tool Corporation Neutral-centering valve control system
GB9211898D0 (en) 1992-06-05 1992-07-15 Vickers Systems Ltd Two-stage hydraulic valves
WO1994010457A1 (en) 1992-10-30 1994-05-11 Bw/Ip International, Inc. Pressure control valve for a hydraulic actuator
JPH06249210A (ja) * 1993-02-26 1994-09-06 Mitsubishi Heavy Ind Ltd 油圧機器同調制御装置
US5499320A (en) 1993-03-24 1996-03-12 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Extended task space control for robotic manipulators
JPH0777275A (ja) 1993-09-08 1995-03-20 Jatco Corp 自動変速機の油圧制御装置
DE4447543C2 (de) 1994-06-28 1997-04-17 Daimler Benz Ag Servoventilanordnung
JP3293455B2 (ja) 1996-04-04 2002-06-17 アイシン・エィ・ダブリュ株式会社 自動変速機の制御装置
JPH09287654A (ja) 1996-04-19 1997-11-04 Aisin Aw Co Ltd 自動変速機の制御装置
US5872893A (en) 1996-07-25 1999-02-16 Honda Giken Kogyo Kabushiki Kaisha Gait generation system of legged mobile robot
JP3047821B2 (ja) 1996-08-29 2000-06-05 双葉電子工業株式会社 模型用エンジンの燃料加圧制御弁
KR100470318B1 (ko) 1997-06-11 2005-07-01 고요 세이코 가부시키가이샤 동력보조스티어링기어용서보밸브
US6067892A (en) 1998-03-18 2000-05-30 Erickson; Joel R. Artificial muscle actuator assembly
US6269733B1 (en) 1999-04-30 2001-08-07 Dennis K. Reust Force servo actuator with asymmetric nonlinear differential hydraulic force feedback
JP3615702B2 (ja) 1999-11-25 2005-02-02 ソニー株式会社 脚式移動ロボットの動作制御装置及び動作制御方法、並びに、脚式移動ロボット
DE10104101A1 (de) 2000-02-10 2001-08-16 Luk Lamellen & Kupplungsbau Drucksteuerventil
DE10006141A1 (de) * 2000-02-11 2001-09-06 Zf Lenksysteme Gmbh Elektrohydraulische Steuervorrichtung
DE10019254C2 (de) 2000-04-18 2002-04-25 Brueninghaus Hydromatik Gmbh Drucksteuerventil
JP4178736B2 (ja) * 2000-08-30 2008-11-12 株式会社デンソー テーブル送りシステム
US6467264B1 (en) * 2001-05-02 2002-10-22 Husco International, Inc. Hydraulic circuit with a return line metering valve and method of operation
US7153242B2 (en) 2001-05-24 2006-12-26 Amit Goffer Gait-locomotor apparatus
JP4188607B2 (ja) 2001-06-27 2008-11-26 本田技研工業株式会社 二足歩行移動体の床反力推定方法及び二足歩行移動体の関節モーメント推定方法
US7217247B2 (en) 2002-09-23 2007-05-15 Honda Giken Kogyo Kabushiki Kaisha Gravity compensation method in a human assist system and a human assist system with gravity compensation control
JP3674778B2 (ja) 2001-09-27 2005-07-20 本田技研工業株式会社 脚式移動ロボットの脚体関節アシスト装置
JP3569764B2 (ja) 2001-11-19 2004-09-29 独立行政法人 科学技術振興機構 二脚歩行式移動装置およびその歩行制御装置並びに歩行制御方法
US6966882B2 (en) 2002-11-25 2005-11-22 Tibion Corporation Active muscle assistance device and method
US7308848B2 (en) * 2004-12-02 2007-12-18 Sarcos Investments Lc Pressure control valve having intrinsic feedback system
US7284471B2 (en) 2004-12-02 2007-10-23 Sarcos Investments Lc Pressure control valve having intrinsic mechanical feedback system
US20060249315A1 (en) 2005-03-31 2006-11-09 Massachusetts Institute Of Technology Artificial human limbs and joints employing actuators, springs, and variable-damper elements
US7313463B2 (en) 2005-03-31 2007-12-25 Massachusetts Institute Of Technology Biomimetic motion and balance controllers for use in prosthetics, orthotics and robotics
JP4595727B2 (ja) 2005-07-22 2010-12-08 ソニー株式会社 外力推定システム及び外力推定方法、並びにコンピュータ・プログラム
DE102005037619B4 (de) * 2005-08-09 2020-07-09 Brueninghaus Hydromatik Gmbh Regelventileinheit mit Wechselanschlag
US7190141B1 (en) 2006-01-27 2007-03-13 Villanova University Exoskeletal device for rehabilitation
US7409825B2 (en) 2006-08-02 2008-08-12 Husco International, Inc. Hydraulic system with a cylinder isolation valve
JP5460335B2 (ja) 2007-02-28 2014-04-02 レイセオン カンパニー 選択的に起動可能な作動装置を有する流体制御システム

Also Published As

Publication number Publication date
US8061261B2 (en) 2011-11-22
WO2008106611A1 (en) 2008-09-04
US20080216644A1 (en) 2008-09-11
EP2122185A1 (en) 2009-11-25
JP2010520418A (ja) 2010-06-10

Similar Documents

Publication Publication Date Title
JP5460335B2 (ja) 選択的に起動可能な作動装置を有する流体制御システム
JP5232227B2 (ja) 非対称バルブ作動構造を持つ圧力制御バルブ
US7509905B2 (en) Pressure control valve having intrinsic mechanical feedback system
JP6629229B2 (ja) 変速機制御部
JP5661085B2 (ja) 作業機械の油圧駆動装置
WO2014034510A1 (ja) アクチュエータ
JP2012527586A (ja) 移動式油圧装置、移動式油圧機械およびバルブユニットのための油圧切換機構
JP5232177B2 (ja) 作動装置を能動的および受動的に作動させる対立する流体制御システム
JP6159629B2 (ja) 流体圧制御装置
JP6788395B2 (ja) シリンダ駆動装置
JP2004353859A (ja) 建設重装備用アクチュエータ油量可変制御装置
US20060144218A1 (en) Pressure control valve having intrinsic feedback system
EP3421819B1 (en) Anti-cavitation hydraulic circuit
JP5514082B2 (ja) デッキクレーンの液圧駆動システム
CN107002716A (zh) 用于调节阀、尤其蒸汽涡轮机调节阀的伺服驱动装置和其运行方法
JP6977072B2 (ja) 切替弁、電動油圧回路及び航空機
CN100572825C (zh) 具有固有反馈系统的压力调节阀
JP2021116839A (ja) 電動油圧回路及び航空機
JP2015098936A (ja) 油圧制御弁
CN112739914B (zh) 具有用于每个致动方向的不同的泵的双作用液压致动器
JPH08135602A (ja) 方向制御弁
WO2020070936A1 (ja) ブレーキバルブ装置及びモータ装置
PL141305B1 (en) Cut-off valve in particular for hydraulic driving systems

Legal Events

Date Code Title Description
A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20110228

A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20110228

A711 Notification of change in applicant

Free format text: JAPANESE INTERMEDIATE CODE: A712

Effective date: 20110629

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20121025

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20121105

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20130131

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20130221

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20130322

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20160329

Year of fee payment: 3

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

LAPS Cancellation because of no payment of annual fees