US20050084387A1 - Control system for hydrostatic pump - Google Patents

Control system for hydrostatic pump Download PDF

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Publication number
US20050084387A1
US20050084387A1 US10/686,369 US68636903A US2005084387A1 US 20050084387 A1 US20050084387 A1 US 20050084387A1 US 68636903 A US68636903 A US 68636903A US 2005084387 A1 US2005084387 A1 US 2005084387A1
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US
United States
Prior art keywords
swashplate
microprocessor
pressure control
control system
signal
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.)
Abandoned
Application number
US10/686,369
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English (en)
Inventor
Craig Klocke
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.)
Danfoss Power Solutions Inc
Original Assignee
Sauer Danfoss Inc
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 Sauer Danfoss Inc filed Critical Sauer Danfoss Inc
Priority to US10/686,369 priority Critical patent/US20050084387A1/en
Assigned to SAUER-DANFOSS INC. reassignment SAUER-DANFOSS INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KLOCKE, CRAIG C.
Priority to DE102004050132A priority patent/DE102004050132A1/de
Priority to JP2004299471A priority patent/JP2005121020A/ja
Priority to CN200410085544.9A priority patent/CN1607333A/zh
Publication of US20050084387A1 publication Critical patent/US20050084387A1/en
Abandoned legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
    • F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F04B1/26—Control
    • F04B1/30—Control of machines or pumps with rotary cylinder blocks
    • F04B1/32—Control of machines or pumps with rotary cylinder blocks by varying the relative positions of a swash plate and a cylinder block
    • F04B1/324—Control of machines or pumps with rotary cylinder blocks by varying the relative positions of a swash plate and a cylinder block by changing the inclination of the swash plate
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/06—Control using electricity
    • F04B49/065—Control using electricity and making use of computers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B2201/00—Pump parameters
    • F04B2201/12—Parameters of driving or driven means
    • F04B2201/1205—Position of a non-rotating inclined plate
    • F04B2201/12051—Angular position

Definitions

  • This invention relates to a control system for a hydrostatic unit. More specifically, and without limitation, this invention relates to a control system that utilizes a dither signal incorporated with its normal input signal in order to adjust the angle of a swashplate.
  • hydrostatic transmission In the art of hydraulics, oil is pumped by mechanical hydraulic pumps for the purpose of causing a hydraulic motor to revolve, a hydraulic cylinder extend, or for other useful purposes.
  • a common aspect of many tractors, earthmoving machines, and the like is a hydrostatic transmission.
  • a hydrostatic transmission consists of a hydrostatic pump which is normally driven by an internal combustion engine, and provides a source of pressurized oil flow which causes one or more hydrostatic motors to rotate. The rotation of these one or more hydrostatic motors will cause the machine to travel forward or reverse as commanded by the drive of the machine.
  • the swashplate is a mechanism in a hydrostatic transmission that controls the fluid flow that a hydraulic pump may deliver.
  • the angle of the swashplate is determined by a hydraulic cylinder or servo system based on information that a control system or microprocessor receives.
  • a typical microprocessor uses an algorithm to determine an output signal that will adjust the swashplate to a position.
  • the pump and servo system usually do not match the resolution and accuracy of the input signal to the hydrostatic unit. This can cause the incorrect positioning of the swashplate.
  • Another object of the present invention is to use a dither signal to improve the resolution and accuracy of fluid flow (e.g. swash angle position) of the pump and/or motor in a hydrostatic control system.
  • Yet another object of the present invention is to provide a hydrostatic control system that is able to adjust a swashplate angle based on system parameters using a dithered signal.
  • the present invention is a control system that controls the angle of a swashplate.
  • the control system can be a microprocessor that receives information from a feedback sensor and setpoint sensor.
  • the microprocessor determines not only the angle of the swashplate but also a set point command. From the information received from the sensor(s), the microprocessor uses an algorithm to process the information and send out an output command signal.
  • the microprocessor can simultaneously send out a superimposed dither signal that produces a resulting signal that drives a pressure control.
  • the pressure control in turn causes a servo system to alter the angle of the swashplate.
  • FIG. 1 is an exploded view of the hydrostatic pump of this system
  • FIG. 2 is a block representation of the control system of the present invention
  • FIG. 3 is an enlarged scale portion 3 - 3 of FIG. 1 ;
  • FIG. 4 is an enlarged scale portion 4 - 4 of FIG. 1 ;
  • FIG. 5 is an enlarged scale portion 5 - 5 of FIG. 1 .
  • the control system of the present invention can be connected to the hydrostatic pump seen in FIG. 1 .
  • the hydrostatic pump 10 has a central housing 12 of a standard servo hydrostatic pump.
  • a servo piston 14 is disposed through the central housing 12 .
  • the servo piston 14 incorporates a servo screw 16 , spring guide 18 , servo spring 20 , and spring seat 22 .
  • the hydrostatic pump 10 also has a swashplate 24 .
  • Swashplate 24 is connected to a shaft feedback assembly 26 that works with the angle sensor assembly 28 to determine the angle of the swashplate 24 .
  • the swashplate 24 connects to the central housing 12 by use of a cone bearing 30 that is connected to cup bearing 32 which is then connected to a first O-ring 34 .
  • the first O-ring 34 rests against the bottom of plate adapter 36 .
  • a second O-ring 38 meshes between the plate adapter 36 and the bottom of the central housing 12 .
  • On the top of the housing is a bi-directional pressure control PCP assembly 39 having two coils. As one can appreciate from FIG. 1 this is a standard servo hydrostatic pump.
  • FIG. 2 shows in block form a typical closed loop control system can used to drive hydrostatic pump 10 .
  • the control system includes feedback sensor 40 and an operational parameter setpoint sensor 42 .
  • the setpoint sensor 42 sends a setpoint signal 44 and the feedback sensor 40 detects the angle of the swashplate 24 and sends a feedback signal 46 .
  • Both the setpoint signal 44 and the feedback signal 46 are received by a device having the capability to produce a dithered electrical control signal.
  • This device in a preferred embodiment is a microprocessor 48 as pictured; however, in alternative embodiments the device may be an electric joystick, an electric foot pedal control, or any other device that can produce a dithered output signal.
  • the microprocessor 48 then sends out a control signal 50 comprised of an average signal and a dither signal.
  • a pressure control 52 then receives the control signal 50 and creates a pressure signal 54 or 56 that is sent to a servo system 58 .
  • the servo system 58 then produces a force 60 that alters the position of swashplate 24 .
  • the feedback sensor 40 is optional as the system can improve performance in a closed loop as well as open loop mode.
  • an error signal is generated which is processed through a typical closed loop algorithm.
  • These algorithms include, but are not limited to, PID, PID plus feed forward, and KIDT1. From the output of the algorithm(s) the microprocessor 48 creates an output signal that is superimposed with a dither signal generating the resulting signal 50 that is received by pressure control 52 .
  • the pressure control 52 can be of any type, including but not limited to a flapper nozzle style pilot valve with two boost spools, a flapper nozzle style pilot valve with one boost spool, a flow control (a device that converts an electrical signal into an hydraulic signal to position the swashplate), or a plurality of pressure controls.
  • the pressure control 52 responds to the output signal and the dither to generate a dithering servo pressure. Based on this dithering servo pressure the max slew rate of the swashplate 24 is determined.
  • the pump swashplate 24 position is therefore determined by the typical force balance of the servo springs, servo pressure, pressure moments, speed moments, and other system factors.
  • the dither signal created by the microprocessor 48 can be independent or dependent of the swash angle value related by feedback sensor 40 .
  • the feedback sensor 40 and the closed loop algorithm used by the microprocessor can be any standard feedback sensor or algorithm.
  • the microprocessor 48 generates the dither signal; however, the dither signal could also be generated internally in the pressure control 52 or externally in another device.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Reciprocating Pumps (AREA)
  • Control Of Positive-Displacement Pumps (AREA)
US10/686,369 2003-10-15 2003-10-15 Control system for hydrostatic pump Abandoned US20050084387A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US10/686,369 US20050084387A1 (en) 2003-10-15 2003-10-15 Control system for hydrostatic pump
DE102004050132A DE102004050132A1 (de) 2003-10-15 2004-10-14 Steuersystem für hydrostatische Pumpe
JP2004299471A JP2005121020A (ja) 2003-10-15 2004-10-14 液圧ポンプのための制御システム
CN200410085544.9A CN1607333A (zh) 2003-10-15 2004-10-15 静压泵控制系统

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US10/686,369 US20050084387A1 (en) 2003-10-15 2003-10-15 Control system for hydrostatic pump

Publications (1)

Publication Number Publication Date
US20050084387A1 true US20050084387A1 (en) 2005-04-21

Family

ID=34520749

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/686,369 Abandoned US20050084387A1 (en) 2003-10-15 2003-10-15 Control system for hydrostatic pump

Country Status (4)

Country Link
US (1) US20050084387A1 (enExample)
JP (1) JP2005121020A (enExample)
CN (1) CN1607333A (enExample)
DE (1) DE102004050132A1 (enExample)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090133951A1 (en) * 2007-11-28 2009-05-28 Caterpillar Paving Products Inc. Method for operating a hydrostatically driven vehicle
US20100150747A1 (en) * 2008-12-12 2010-06-17 Caterpillar Inc. Pump having pulsation-reducing engagement surface
WO2014096129A1 (en) * 2012-12-20 2014-06-26 Eaton Industrial IP GmbH & Co. KG Swashplate position sensor arrangement
CN104251245A (zh) * 2013-06-28 2014-12-31 伊顿公司 伺服泵控制系统及方法
WO2015017263A1 (en) * 2013-07-30 2015-02-05 Parker-Hannifin Corporation Overshoot reduction on pump controls
WO2015148002A1 (en) * 2014-03-27 2015-10-01 General Electric Company System and method for controlling an integrated pump and energy recovery system
US20150292499A1 (en) * 2014-04-14 2015-10-15 Parker-Hannifin Corporation Hydraulically controlled hydrostatic transmission
US9234532B2 (en) 2008-09-03 2016-01-12 Parker-Hannifin Corporation Velocity control of unbalanced hydraulic actuator subjected to over-center load conditions
EP3690229A1 (en) * 2019-01-31 2020-08-05 Eaton Intelligent Power Limited Displacement control with angle sensor adjustment

Citations (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US456403A (en) * 1891-07-21 Island
US4546403A (en) * 1984-03-02 1985-10-08 Ford Motor Company Solenoid switching driver with solenoid current proportional to an analog voltage
US4606313A (en) * 1980-10-09 1986-08-19 Hitachi Construction Machinery Co., Ltd. Method of and system for controlling hydraulic power system
US4747754A (en) * 1986-09-05 1988-05-31 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Variable displacement wobble plate type compressor with solenoid-operated wobble angle control unit
US4960365A (en) * 1988-12-01 1990-10-02 Daikin Industries, Ltd. Hydraulic control apparatus
US5285913A (en) * 1992-11-24 1994-02-15 H-C Industries, Inc. Closure assembly with insert liner
US5432693A (en) * 1993-04-01 1995-07-11 Ford Motor Company Digital pulse width modulator circuit with proportional dither
US5673166A (en) * 1995-05-17 1997-09-30 Caterpillar Inc. Dither magnitude control
US5947086A (en) * 1996-10-18 1999-09-07 Hitachi, Ltd. Throttle valve control apparatus
US6126405A (en) * 1996-06-17 2000-10-03 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Undulating current supplying means for the solenoid of a displacement control valve in a variable displacement compressor
US6285913B1 (en) * 1995-09-22 2001-09-04 Alfa Laval Automation Ab Method and control system for compensating for friction
US6375433B1 (en) * 2000-07-07 2002-04-23 Caterpillar Inc. Method and apparatus for controlling pump discharge pressure of a variable displacement hydraulic pump
US20020176784A1 (en) * 2001-05-16 2002-11-28 Hongliu Du Method and apparatus for controlling a variable displacement hydraulic pump
US6516235B1 (en) * 1999-05-26 2003-02-04 Toyota Jidosha Kabushiki Kaisha Control apparatus and method of control system having sliding resistance
US20030044289A1 (en) * 2001-09-06 2003-03-06 Mikio Matsuda Variable capacity compressor
US20030121500A1 (en) * 2001-12-28 2003-07-03 Hitachi Unisia Automotive, Ltd. Ignition timing control apparatus for internal combustion engine and method thereof
US6648014B1 (en) * 1999-09-01 2003-11-18 Ebara Corporation Fluid control valve and plate with filter

Patent Citations (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US456403A (en) * 1891-07-21 Island
US4606313A (en) * 1980-10-09 1986-08-19 Hitachi Construction Machinery Co., Ltd. Method of and system for controlling hydraulic power system
US4546403A (en) * 1984-03-02 1985-10-08 Ford Motor Company Solenoid switching driver with solenoid current proportional to an analog voltage
US4747754A (en) * 1986-09-05 1988-05-31 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Variable displacement wobble plate type compressor with solenoid-operated wobble angle control unit
US4960365A (en) * 1988-12-01 1990-10-02 Daikin Industries, Ltd. Hydraulic control apparatus
US5285913A (en) * 1992-11-24 1994-02-15 H-C Industries, Inc. Closure assembly with insert liner
US5432693A (en) * 1993-04-01 1995-07-11 Ford Motor Company Digital pulse width modulator circuit with proportional dither
US5673166A (en) * 1995-05-17 1997-09-30 Caterpillar Inc. Dither magnitude control
US6285913B1 (en) * 1995-09-22 2001-09-04 Alfa Laval Automation Ab Method and control system for compensating for friction
US6126405A (en) * 1996-06-17 2000-10-03 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Undulating current supplying means for the solenoid of a displacement control valve in a variable displacement compressor
US5947086A (en) * 1996-10-18 1999-09-07 Hitachi, Ltd. Throttle valve control apparatus
US6516235B1 (en) * 1999-05-26 2003-02-04 Toyota Jidosha Kabushiki Kaisha Control apparatus and method of control system having sliding resistance
US6648014B1 (en) * 1999-09-01 2003-11-18 Ebara Corporation Fluid control valve and plate with filter
US6375433B1 (en) * 2000-07-07 2002-04-23 Caterpillar Inc. Method and apparatus for controlling pump discharge pressure of a variable displacement hydraulic pump
US20020176784A1 (en) * 2001-05-16 2002-11-28 Hongliu Du Method and apparatus for controlling a variable displacement hydraulic pump
US20030044289A1 (en) * 2001-09-06 2003-03-06 Mikio Matsuda Variable capacity compressor
US20030121500A1 (en) * 2001-12-28 2003-07-03 Hitachi Unisia Automotive, Ltd. Ignition timing control apparatus for internal combustion engine and method thereof

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090133951A1 (en) * 2007-11-28 2009-05-28 Caterpillar Paving Products Inc. Method for operating a hydrostatically driven vehicle
US8020659B2 (en) * 2007-11-28 2011-09-20 Caterpillar Paving Products Inc. Hydrostatically driven vehicle and method therefor
US9234532B2 (en) 2008-09-03 2016-01-12 Parker-Hannifin Corporation Velocity control of unbalanced hydraulic actuator subjected to over-center load conditions
US8333571B2 (en) * 2008-12-12 2012-12-18 Caterpillar Inc. Pump having pulsation-reducing engagement surface
US20100150747A1 (en) * 2008-12-12 2010-06-17 Caterpillar Inc. Pump having pulsation-reducing engagement surface
WO2014096129A1 (en) * 2012-12-20 2014-06-26 Eaton Industrial IP GmbH & Co. KG Swashplate position sensor arrangement
CN104251245A (zh) * 2013-06-28 2014-12-31 伊顿公司 伺服泵控制系统及方法
US10458403B2 (en) 2013-06-28 2019-10-29 Eaton Intelligent Power Limited Servo pump control system and method
WO2015017263A1 (en) * 2013-07-30 2015-02-05 Parker-Hannifin Corporation Overshoot reduction on pump controls
WO2015148002A1 (en) * 2014-03-27 2015-10-01 General Electric Company System and method for controlling an integrated pump and energy recovery system
US20150292499A1 (en) * 2014-04-14 2015-10-15 Parker-Hannifin Corporation Hydraulically controlled hydrostatic transmission
EP2955379A3 (en) * 2014-04-14 2016-01-20 Parker-Hannificn Corporation Hydraulically controlled hydrostatic transmission
EP3690229A1 (en) * 2019-01-31 2020-08-05 Eaton Intelligent Power Limited Displacement control with angle sensor adjustment
US11608825B2 (en) 2019-01-31 2023-03-21 Danfoss Power Solutions Ii Technology A/S Displacement control with angle sensor adjustment

Also Published As

Publication number Publication date
JP2005121020A (ja) 2005-05-12
DE102004050132A1 (de) 2005-05-25
CN1607333A (zh) 2005-04-20

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Legal Events

Date Code Title Description
AS Assignment

Owner name: SAUER-DANFOSS INC., IOWA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KLOCKE, CRAIG C.;REEL/FRAME:014932/0763

Effective date: 20031009

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION