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WO2000058565A1 - Systeme de position libre du godet - Google Patents

Systeme de position libre du godet Download PDF

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Publication number
WO2000058565A1
WO2000058565A1 PCT/US2000/008146 US0008146W WO0058565A1 WO 2000058565 A1 WO2000058565 A1 WO 2000058565A1 US 0008146 W US0008146 W US 0008146W WO 0058565 A1 WO0058565 A1 WO 0058565A1
Authority
WO
WIPO (PCT)
Prior art keywords
physical quality
operable
signal
pressure
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.)
Ceased
Application number
PCT/US2000/008146
Other languages
English (en)
Inventor
David J. Rocke
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.)
Caterpillar Inc
Original Assignee
Caterpillar 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 Caterpillar Inc filed Critical Caterpillar Inc
Publication of WO2000058565A1 publication Critical patent/WO2000058565A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/2025—Particular purposes of control systems not otherwise provided for
    • E02F9/2029—Controlling the position of implements in function of its load, e.g. modifying the attitude of implements in accordance to vehicle speed
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
    • E02F3/36—Component parts
    • E02F3/42—Drives for dippers, buckets, dipper-arms or bucket-arms
    • E02F3/43—Control of dipper or bucket position; Control of sequence of drive operations
    • E02F3/431—Control of dipper or bucket position; Control of sequence of drive operations for bucket-arms, front-end loaders, dumpers or the like
    • E02F3/432—Control of dipper or bucket position; Control of sequence of drive operations for bucket-arms, front-end loaders, dumpers or the like for keeping the bucket in a predetermined position or attitude

Definitions

  • This invention relates generally to controlling a work implement on an operating machine, and more specifically to a method and apparatus for controlling the drag pressure of the work implement.
  • Many conventional operating machines consist of a motorized chassis, such as a tractor or loader, and a hydraulically controlled work implement, such as a bucket or a blade.
  • a hydraulic cylinder or more typically a pair of hydraulic cylinders control the position and motion of the work implement.
  • the hydraulics of some operating machines include a "float" mode.
  • Float mode may be used to scrape a layer of debris off of the ground, or to locate the work implement on the ground in preparation for digging into a pile of material .
  • the hydraulic system opens hydraulic paths to and from the hydraulic cylinders, allowing for a relatively unrestricted flow of hydraulic fluid to and from the hydraulic cylinders.
  • the hydraulic cylinders no longer exert a controlling force on the work implement, and the position of the work implement freely changes as external forces are exerted on the work implement.
  • the most common example is the bucket of a loader resting on a surface of the ground. When the loader is in motion, the bucket is pushed up by rising terrain and pulled down by gravity with falling terrain, effectively "floating" on the surface of the ground.
  • the weight of a typical work implement may be considerable. Bucket weights for some heavy- equipment range from 2,800 lbs. to 50,000 lbs.
  • the weight of the work implement may press itself into the ground with a significant drag pressure, and may cause the implement to gouge into the ground, plowing it.
  • the work implement removes a layer of the ground in addition to the intended material . This is undesirable, as it unintentionally changes the surface of the ground and may decrease the volume of the work implement available for the intended payload.
  • the present invention provides methods and apparatuses for controlling the position of a work implement on an operating machine having a hydraulic cylinder coupled with the work implement and operable to move the work implement .
  • the apparatus includes a first sensor coupled with the hydraulic cylinder.
  • the first sensor measures a first physical quality exerted on the hydraulic cylinder and transmits a first signal as a function of the first physical quality exerted on the hydraulic cylinder.
  • a controller is coupled with the first sensor to receive the first signal, and to determine if a net physical quality is within a predetermined range, the net physical quality being a function of the first signal. If the net physical qualityis not within the predetermined range, the controller transmits an adjustment signal to a fluid pump system.
  • the fluid pump system pressurizes hydraulic fluid as a function of receiving the adjustment signal.
  • An actuator is coupled with the fluid pump system to receive the pressurized fluid, and changes the position of the work implement as a function of receiving the pressurized fluid.
  • Figure 1 is a functional block diagram of a float control apparatus according to one embodiment of the invention, installed on a forward portion of an operating machine.
  • Figure 2 is a side view and block diagram of one embodiment of the float control apparatus installed on a wheel loader.
  • FIG. 3 is a flowchart of a control algorithm according to one embodiment of the invention.
  • FIG. 1 is a functional block diagram of a float control apparatus 10 according to one embodiment of the invention, installed on a forward portion of an operating machine, such as a wheel loader 100.
  • the float control apparatus 10 includes a first sensor, such as a first pressure sensor 12, a second sensor, such as a second pressure sensor 14, a controller 16, an actuator, such as a hydraulic cylinder 30, coupled with a fluid pump system 18, as described below, and an input device, such as an infinitely variable dial 20.
  • a first sensor such as a first pressure sensor 12
  • a second sensor such as a second pressure sensor 14
  • a controller 16 an actuator, such as a hydraulic cylinder 30, coupled with a fluid pump system 18, as described below
  • an input device such as an infinitely variable dial 20.
  • operating machines typically use at least two pairs of hydraulic cylinders 30 to exercise a work assembly, only one of each pair is shown for purposes of simplicity. A greater or lesser number of hydraulic cylinders 30 may, of course, also be used.
  • the first and second pressure sensors 12, 14 are coupled with the hydraulic cylinder 30 having a first area 32, a second area 34, and a piston 36 having a first face 38 and a second face 40.
  • the first and second sensors respectively monitor the hydraulic pressure of a hydraulic fluid (not shown) within the first and second areas 32, 34.
  • the second area 34 surrounds a cylinder rod 56.
  • the first and second pressure sensors 12, 14 respectively transmit a first and second pressure signal corresponding to the hydraulic pressure within the respective first and second areas 32, 34.
  • the first and second sensors 12, 14 may be any of a variety of appropriate sensors that are capable of providing a signal indicative of a physical quality, such as pressure or force, including pneumatic pressure .
  • the controller 16 is coupled with the first and second pressure sensors 12, 14 to receive the first and second pressure signals.
  • the controller 16 determines a cylinder force (F cy ⁇ ) , as described below, that corresponds to a drag pressure of a bucket assembly 50.
  • the cylinder force (F cy ⁇ ) is determined as a function of the first and second pressure signals.
  • the drag pressure is the pressure that the bucket assembly 50 applies to the ground. In float mode, the drag pressure typically corresponds to the weight of, or a percentage of the weight of the bucket assembly 50.
  • the bucket assembly 50 includes a work implement, such as a bucket 52 or blade (not shown), and a lift arm 54 that is coupled with the hydraulic cylinder 30.
  • the weight of the bucket assembly 50 transmitted through the cylinder rod 56, and born by the piston 36 decreases, and vice versa.
  • the piston 36 exerts a lesser force on the hydraulic fluid within the first area 32, thereby decreasing the pressure of the hydraulic fluid within the first area 32.
  • the piston 36 exerts a greater force on the hydraulic fluid within the first area 32, increasing the pressure of the hydraulic fluid within the first area 32.
  • the precise mathematical relationship between the drag pressure of the bucket assembly 50 and the pressure within the first and second areas 32, 34 will vary with the specifications of the bucket assembly 50 and the hydraulic cylinder 30. This relationship may be approximately calculated based on the known geometries and weights, for example, or may be determined by experiment. Once determined, the relationship may be programmed into the controller 16.
  • F h2 A 2 * P 2
  • Ai is the area of the first face 38 of the piston 36 and P ⁇ is the pressure of the hydraulic fluid on the first face 38, i.e., in the first area 32
  • a 2 is the area of the second face 40 of the piston 36 and P 2 is the pressure of the hydraulic fluid in the second area 34.
  • the quantities Ai and A 2 are known from the cylinder 30 geometry, and P x and P 2 are measured with pressure sensors 12, 14. It should be noted that the quantities A x and A 2 remain constant, and therefore measuring pressures P ⁇ and P 2 is tantamount to measuring forces F ⁇ and F 2 .
  • the drag pressure of the bucket assembly 50 is a function of the force of the cylinder (F cy ⁇ ) applied to the fluid within the first area 32.
  • F cy ⁇ force of the cylinder
  • a single sensor 12 may be used instead to determine the drag pressure in the float control apparatus 10. The force exerted on the second face 40 by the fluid within the second area 34 is ignored, and therefore,
  • the float control apparatus 10 otherwise functions similarly to what is described above, and will not be repeated in the interest of brevity.
  • the drag pressure calculated using a single pressure sensor 12 will generally not be as accurate as the float control apparatus 10 having two pressure sensors 12, 14, but for small values of P 2 , the amount of deviation from the two sensor float control apparatus 10 will be low.
  • the controller 16 is operable to determine F cy ⁇ and to generate an adjustment signal when F cy ⁇ is not within a predetermined range.
  • the adjustment signal indicates whether the drag pressure is too high or too low. If the drag pressure is above the predetermined range, the controller 16 transmits an adjustment signal having first characteristics, such as being a relatively high voltage, such as V cc . If the drag pressure is below the predetermined range, the controller 16 transmits an adjustment signal having second characteristics, such as being a relatively low voltage, such as ground.
  • first characteristics such as being a relatively high voltage, such as V cc .
  • second characteristics such as being a relatively low voltage, such as ground.
  • Other characteristics and/or types of adjustment signals known to those skilled in the art, such as pulse width or frequency modulation, or using a current, may also be used to denote the drag pressure being too high or low.
  • the adjustment signal may also be generated strictly as a function of the first and second pressure signals, without calculating the force of the piston 36 (F cy ⁇ ) .
  • the adjustment signal is generated when the pressure of fluid within the first area 32 is within a predetermined range and/or the pressure within the second area 34 is within another predetermined range. Again, the predetermined ranges may be determined by calculation or experiment.
  • the hydraulic pump system 18 is coupled with the controller 16 to receive the adjustment signal, and is operable to cause the hydraulic cylinder 30 to change the position of the bucket assembly 50 as a function of receiving the adjustment signal.
  • the hydraulic pump system 18 includes a tank 19, a main pump 21, a pilot pump 23, a main manifold 25 having a valve 27, and a pilot manifold 29.
  • a variety of other fluid pump and cylinder configurations known to those skilled in the art may also be used, as appropriate.
  • the functioning of hydraulic systems using hydraulic pumps and cylinders is known to those skilled in the art, and will not be discussed in the interest of brevity.
  • FIG. 2 is a side view and block diagram of one embodiment of the float control apparatus 10 installed on the wheel loader 100.
  • the wheel loader includes a conventional chassis 112, an engine 114 coupled with the chassis 112 and operable to generate a propelling force, a propulsion system 116, such as a transmission, drive shaft, and a wheel or a track, coupled with the engine to receive the propelling force and to drive the loader 100, a work implement, such as the bucket 52, coupled with the chassis 112, and the hydraulic cylinder 30 coupled with the bucket 52 and chassis 112.
  • a propulsion system 116 such as a transmission, drive shaft, and a wheel or a track
  • the percentage of the weight of the bucket assembly 50 supported by the ground may vary. For example, if the bucket 52 encounters an upslope, the weight of the bucket assembly 50 born by the ground will increase as the ground presses against the bucket 52. The additional supporting pressure from the ground will decrease the weight of the bucket assembly 50 born by the hydraulic cylinder 30, thus decreasing the pressure exerted by the weight of the bucket assembly 50 through the cylinder rod 56 on the piston 36 of the hydraulic cylinder 30. The decrease in pressure on the piston 36 is detected by the first and second pressure sensors 12, 14 and may be calculated as described above.
  • the controller 16 transmits the adjustment signal to the hydraulic pump system 18, causing the hydraulic pump system 18 to effect a fluid flow to/from the hydraulic cylinder 30 that raises the bucket assembly 50.
  • the bucket 52 encounters an upslope, the bucket 52 is automatically raised.
  • the controller 16 stops transmitting the adjustment signal, thereby stopping the upward movement of the bucket 52 in a position that causes the desired drag pressure .
  • the controller 16 transmits the adjustment signal to the hydraulic pump system 18, causing the hydraulic pump system 18 to effect a fluid flow to/from the hydraulic cylinder 30 that lowers the bucket assembly 50.
  • the bucket 52 is automatically lowered.
  • the controller 16 stops transmitting the adjustment signal, thereby stopping the downward movement of the bucket 52 in a position that causes the desired drag pressure .
  • the bucket 52 can be made to float over the surface of the ground without digging into and plowing the ground, regardless of the weight of the bucket assembly 50 or the contours of the ground. Alternately, the bucket 52 may be made to remove a layer of the ground by selecting an appropriately high drag pressure.
  • An input device such as the infinitely variable dial 20 or a multi-position switch (not shown) may be used to input a desired drag pressure to the float control apparatus 10.
  • the dial 20 transmits a desired drag pressure signal to the controller 16 as a function of the position of the dial 20.
  • the desired pressure signal may correspond to a single pressure or a range of pressures.
  • a float control apparatus 10 has a programmable, and variable drag pressure, i.e., a variable float system.
  • the desired drag pressure may also be programmed into the controller 16 during manufacturing of the controller 16, including being hard-wired or burned into a memory (not shown) .
  • an operator may place the bucket 52 in a position to cause a desired drag pressure.
  • the controller 16 reads the pressure signals from the first and second pressure sensors 12, 14. The controller calculates, as described above, a baseline pressure equal to the current force on the piston 36, and thereafter regulates the pressure to the sampled baseline pressure.
  • a button or switch (not shown) is typically coupled with the controller 16 to provide a signal indicating that the controller 16 should read the baseline pressure.
  • the hydraulic pump system is typically coupled with the controller 16 to provide a signal indicating that the controller 16 should read the baseline pressure.
  • the adjustment signal transmitted by the controller 16 has varying characteristics as a function of how far out of the predetermined range the cylinder force (F cy ⁇ ) , and therefore the drag pressure, is.
  • the adjustment signal causes the hydraulic pump system 18 to pump at a relatively low rate, moving the bucket assembly 50 at a relatively low speed.
  • the adjustment signal causes the hydraulic pump system 18 to pump at a relatively high rate, moving the bucket assembly 50 at a relatively high speed.
  • the greater the deviation from the predetermined range the faster the hydraulic pump system 18 moves the bucket assembly 50.
  • Other relationships between the extent to which the drag pressure deviates from the desired drag pressure and the speed at which the bucket assembly 50 moves are also possible.
  • a position sensor such as a rotary potentiometer 62
  • the rotary potentiometer 62 transmits a position signal as a function of the position of the piston 36 within the hydraulic cylinder 30.
  • the controller 16 is coupled with the rotary potentiometer 62 to receive the position signal. When the cylinder 30 is fully or nearly fully collapsed, the controller 16 reads this condition from the position signal, and ceases transmitting the adjustment signal causing the hydraulic pump to lower the bucket assembly 50. This prevents the hydraulic pump 16 from trying to move the cylinder 30 when the cylinder has reached a stop.
  • FIG. 3 shows a flowchart 200 of a preferred embodiment of a control algorithm, such as software control, implemented in connection with one embodiment of the invention. Those skilled in the art may easily write software code implementing the control algorithm.
  • a desired cylinder force (F cy ⁇ ) corresponding to a desired drag pressure is determined.
  • the cylinder force (F cyl ) is measured. If, as determined in block 230, the cylinder force (F cy ⁇ ) is within the range of desired forces from block 210, the process returns to block 220.
  • block 240 it is determined whether the cylinder force (F cy ⁇ ) is too high, i.e., is above the predetermined range from block 210. If so, the bucket assembly is lowered (in block 250), increasing the drag pressure. The process then returns to block 220. Because block 230 has determined that the cylinder force (F cy ⁇ ) is not within the predetermined range, if the cylinder force (F cy ⁇ ) is not above the predetermined range, then it must be below the predetermined range. Therefore, in block 260 the bucket assembly 50 is raised, decreasing the drag pressure.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Operation Control Of Excavators (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

La présente invention concerne des procédés et dispositifs servant à commander le godet équipant une machine de chantier (100) pourvue d'un vérin hydraulique couplé au godet pour la manoeuvre de ce dernier. Un capteur mesurant une première variable physique affectant le vérin hydraulique (30) produit un signal fonction de cette variable. Un contrôleur (16) ayant reçu ce signal vérifie que cette variable nette, fonction du premier signal, reste dans une plage établie. Si ce n'est pas le cas, le contrôleur (16) émet un signal d'ajustement à un système de pompe hydraulique (18). Lorsqu'il a reçu ce signal d'ajustement, le système de pompe hydraulique (18) met en oeuvre l'actionneur servant à modifier la position du godet en fonction du signal d'ajustement reçu.
PCT/US2000/008146 1999-03-31 2000-03-28 Systeme de position libre du godet Ceased WO2000058565A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US28222699A 1999-03-31 1999-03-31
US09/282,226 1999-03-31

Publications (1)

Publication Number Publication Date
WO2000058565A1 true WO2000058565A1 (fr) 2000-10-05

Family

ID=23080577

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Application Number Title Priority Date Filing Date
PCT/US2000/008146 Ceased WO2000058565A1 (fr) 1999-03-31 2000-03-28 Systeme de position libre du godet

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WO (1) WO2000058565A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110258686A (zh) * 2019-06-28 2019-09-20 三一汽车制造有限公司 铲刀升降系统、平地机和控制方法

Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3642159A (en) * 1970-08-19 1972-02-15 Massey Ferguson Inc Earthworking vehicle
US3726428A (en) * 1971-02-04 1973-04-10 Int Harvester Co Control circuit for front end loader
DE2332544A1 (de) * 1973-06-27 1974-09-19 Frisch Gmbh Steueranlage fuer die steuerung des arbeitswerkzeuges einer erdbewegungsmaschine
US4282933A (en) * 1978-02-02 1981-08-11 Kabushiki Kaisha Komatsu Seisakusho Automatic control device for an earth working equipment
JPS5934337A (ja) * 1982-08-20 1984-02-24 Yanmar Agricult Equip Co Ltd ブルド−ザにおける押土装置の制御装置
EP0436740A1 (fr) * 1989-08-02 1991-07-17 Kabushiki Kaisha Komatsu Seisakusho Appareil de commande d'excavation lineaire dans une excavatrice hydraulique
US5065326A (en) * 1989-08-17 1991-11-12 Caterpillar, Inc. Automatic excavation control system and method
EP0532195A2 (fr) * 1991-09-13 1993-03-17 Caterpillar Inc. Procédé et appareil pour le contrôle d'un outil
US5622226A (en) * 1996-01-29 1997-04-22 Caterpillar Inc. Method for controlling bounce of a work implement
EP0785311A2 (fr) * 1996-01-16 1997-07-23 Clark Equipment Company ContrÔles électroniques dans un véhicule de changement à direction par dérapage
DE19800185A1 (de) * 1997-01-06 1998-07-09 Caterpillar Inc System und Verfahren zur automatischen Schaufelbeladung unter Verwendung von Massendurchdringungsfaktoren
US5784945A (en) * 1997-05-14 1998-07-28 Caterpillar Inc. Method and apparatus for determining a valve transform
US5784812A (en) * 1994-07-13 1998-07-28 O&K Orenstein & Koppel Ag Method of controlling the positioning of an outfit tilting cylinder mounted on the descending lift frame of movable construction machines
US5975214A (en) * 1997-01-31 1999-11-02 Komatsu, Ltd. Working machine control device for construction machinery

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3642159A (en) * 1970-08-19 1972-02-15 Massey Ferguson Inc Earthworking vehicle
US3726428A (en) * 1971-02-04 1973-04-10 Int Harvester Co Control circuit for front end loader
DE2332544A1 (de) * 1973-06-27 1974-09-19 Frisch Gmbh Steueranlage fuer die steuerung des arbeitswerkzeuges einer erdbewegungsmaschine
US4282933A (en) * 1978-02-02 1981-08-11 Kabushiki Kaisha Komatsu Seisakusho Automatic control device for an earth working equipment
JPS5934337A (ja) * 1982-08-20 1984-02-24 Yanmar Agricult Equip Co Ltd ブルド−ザにおける押土装置の制御装置
EP0436740A1 (fr) * 1989-08-02 1991-07-17 Kabushiki Kaisha Komatsu Seisakusho Appareil de commande d'excavation lineaire dans une excavatrice hydraulique
US5065326A (en) * 1989-08-17 1991-11-12 Caterpillar, Inc. Automatic excavation control system and method
EP0532195A2 (fr) * 1991-09-13 1993-03-17 Caterpillar Inc. Procédé et appareil pour le contrôle d'un outil
US5784812A (en) * 1994-07-13 1998-07-28 O&K Orenstein & Koppel Ag Method of controlling the positioning of an outfit tilting cylinder mounted on the descending lift frame of movable construction machines
EP0785311A2 (fr) * 1996-01-16 1997-07-23 Clark Equipment Company ContrÔles électroniques dans un véhicule de changement à direction par dérapage
US5622226A (en) * 1996-01-29 1997-04-22 Caterpillar Inc. Method for controlling bounce of a work implement
DE19800185A1 (de) * 1997-01-06 1998-07-09 Caterpillar Inc System und Verfahren zur automatischen Schaufelbeladung unter Verwendung von Massendurchdringungsfaktoren
US5975214A (en) * 1997-01-31 1999-11-02 Komatsu, Ltd. Working machine control device for construction machinery
US5784945A (en) * 1997-05-14 1998-07-28 Caterpillar Inc. Method and apparatus for determining a valve transform

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 008, no. 132 (M - 303) 20 June 1984 (1984-06-20) *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110258686A (zh) * 2019-06-28 2019-09-20 三一汽车制造有限公司 铲刀升降系统、平地机和控制方法
CN110258686B (zh) * 2019-06-28 2021-11-12 三一汽车制造有限公司 铲刀升降系统、平地机和控制方法

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