EP4311887A1 - Procédé et système de commande d'un bras d'un véhicule de travail - Google Patents

Procédé et système de commande d'un bras d'un véhicule de travail Download PDF

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Publication number
EP4311887A1
EP4311887A1 EP23187382.9A EP23187382A EP4311887A1 EP 4311887 A1 EP4311887 A1 EP 4311887A1 EP 23187382 A EP23187382 A EP 23187382A EP 4311887 A1 EP4311887 A1 EP 4311887A1
Authority
EP
European Patent Office
Prior art keywords
front axle
ground
vehicle
arm
organ
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.)
Pending
Application number
EP23187382.9A
Other languages
German (de)
English (en)
Inventor
Adriano GARRAMONE
Stefano Liberti
Andrea Gravili
Antonio Venezia
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.)
CNH Industrial Italia SpA
Original Assignee
CNH Industrial Italia SpA
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 CNH Industrial Italia SpA filed Critical CNH Industrial Italia SpA
Publication of EP4311887A1 publication Critical patent/EP4311887A1/fr
Pending legal-status Critical Current

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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
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2203—Arrangements for controlling the attitude of actuators, e.g. speed, floating function
    • 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
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2221—Control of flow rate; Load sensing arrangements

Definitions

  • the present invention relates to the field of methods and systems for controlling the arms of work vehicles.
  • the hydraulic circuit is powered by a hydraulic pump driven in rotation by a prime mover, very often an internal combustion engine.
  • the hydraulic actuators implemented for moving the users are of the double chamber type, namely a movable piston divides two closed chambers that can be fed alternately by the hydraulic pump.
  • the second chamber When a first chamber is operatively connected to the pump, the second chamber, opposite the first, is connected to a collection tank, where the excess hydraulic liquid is collected.
  • a control valve controls the selective filling of one of the two chambers of an actuator.
  • the valve is proportional, in the sense that there is a first factor of proportionality with the position of a control lever, typically a joystick, arranged in the vehicle cabin.
  • the vehicle gives the operator the opportunity to set the so-called response aggressiveness of the actuators, that is, the response speed.
  • Wheel loaders are equipped with an arm and a bucket hinged to the arm.
  • grade During ground flattening operations, generally referred to as "grading", the boom is pushed down and the bucket is rotated forward to the dump position as the vehicle rolls back.
  • the front axle of the vehicle is raised from the ground, i.e. spaced apart from the ground, and the front of the vehicle rests on the bucket, which exerts a corresponding force on the ground to be flattened.
  • the purpose of the present invention is to make the lowering of the vehicle more delicate, avoiding possible consequences for the operator's health.
  • the basic idea of the present invention is to automatically attenuate the response dynamics of the articulated organ, i.e. the aggressiveness of the actuation, in the movement of the articulated organ aimed at bringing the front axle of the vehicle to contact the ground, when it is detected that the front axle is raised from the ground. In this way, the front axle gradually comes into contact with the ground, significantly reducing the strain on the operator's musculoskeletal system.
  • the term "when” means that the reduction of aggressiveness occurs when, that is, "in response” or to the detection of the lifting of the front axle from the ground, clearly indicating a causal relationship.
  • the lifting of the front axle is due to the over-travel of the arm, then only the aggressiveness of the arm actuator is attenuated.
  • the lifting of the front axle is due only to the forward rotation of the bucket, then only the aggressiveness of the bucket actuator is attenuated.
  • the aggressiveness of both the arm and bucket actuators is attenuated at the same time.
  • the detection of the lifting of the front axle of the vehicle can be achieved in different ways. It is preferred to detect the lifting of the front axle taking into account the composition of the mutual position between the arm and the vehicle frame and of the bucket with respect to the arm.
  • the dependent claims describe preferred variants of the invention, forming an integral part of this description.
  • a work vehicle WL such as a mechanical shovel or an agricultural vehicle provided of arm and bucket, see figure 1 , preferably a wheel loader, comprises a frame F, a front axle AX1, a rear axle AX2, a prime mover E which drives in rotation a hydraulic pump P which allows to pressurize a hydraulic circuit which powers the hydraulic actuators A1, A2 for the movement of an organ B, BK comprising an arm B, having a first end hinged to the frame and a shovel or bucket BK hinged to a second end of the arm, opposite the first end of the arm.
  • a work vehicle WL such as a mechanical shovel or an agricultural vehicle provided of arm and bucket, see figure 1 , preferably a wheel loader, comprises a frame F, a front axle AX1, a rear axle AX2, a prime mover E which drives in rotation a hydraulic pump P which allows to pressurize a hydraulic circuit which powers the hydraulic actuators A1, A2 for the movement of an organ B, BK comprising an arm B,
  • Figure 2 shows an example of a simplified electro-hydraulic diagram for controlling the organ B, BK.
  • the hydraulic actuator A1 also called double action hydraulic cylinder, includes two opposing chambers: one arranged to obtain the lifting of the arm and the other to obtain the lowering of the arm.
  • the actuator A1 is controlled by a proportional control valve V1, while the actuator A2 is controlled by a proportional control valve V2.
  • V1 a proportional control valve
  • V2 a proportional control valve
  • These are preferably of the three-position type with a rest position which puts in direct connection the supply pipe connected with the hydraulic pump P to the collection tank T. Therefore, the pumped liquid is sent directly to the collection tank.
  • the hydraulic pump feeds a first chamber which brings the arm B to rise, while the second chamber, opposite to the first, is connected to the collection tank T.
  • the hydraulic pump feeds the second chamber which brings the arm to lower, while the first chamber is connected with the collection tank T.
  • each actuator is connected to a position sensor S1 and S2 respectively for the actuators A1 and A2.
  • valves V1 and V2 are proportional to a deflection of a relative JOYSTICK control lever, for example in the form of a joystick.
  • control lever is operationally connected with the processing unit CONTROL UNIT and generates an electrical signal that the processing unit processes to control the operation of the control valves V1 and V2.
  • the diagram shown in figure 2 provides for the use of open center directional valves V1 and V2, however other hydraulic diagrams can be implemented while maintaining the setting object of the present invention.
  • the processing unit is configured to control the control valves V1 and V2 according to a first factor of proportionality with the signal generated by the control lever and therefore with a deflection angle of the control lever with respect to a respective rest position.
  • the processing unit is configured to recognize a condition of detachment of the front axle AX1 from the ground SO as a function of a plurality of combinations of the positions of the actuators A1 and A2.
  • the processing unit is configured to apply a second proportionality factor lower than the first proportionality factor when it detects that the front axle is detached from the ground.
  • the second proportionality factor is applied only to the movements of the actuator (s) that causes the front axle of the vehicle to impact with the ground.
  • the actuators A1 and A2 to further move the front axle away from the ground, there is no change in the response aggressiveness of the arm and bucket.
  • the control valves V1 and V2 operate more slowly, obtaining a smoother and more gradual axle lowering.
  • the behaviour of the valves is asymmetrical.
  • the processing unit is configured to restore the behaviour of valves V1 and V2, to the conditions prior to the detection of the detachment of the front axle from the ground.
  • the reset provides that the behaviour of the valves is symmetrical according to the first proportionality factor.
  • the detachment of the front axle of the vehicle can be caused only by one between the arm and the bucket.
  • a change in the behaviour of the control valves may be expected, only of the valve relating to the component, arm or bucket, causing the detachment of the vehicle's front axle from the ground.
  • the change in the behaviour of the control valves is applied to both control valves, regardless of the component causing the detachment of the front axle AX1 of the vehicle from the ground.
  • Figure 3 shows an example of a flow chart of an example of a control method object of the present invention.
  • the method is cyclical and includes:
  • the present invention can be advantageously carried out by means of a computer program which comprises coding means for carrying out one or more steps of the method, when this program is executed on a computer. Therefore, it is intended that the scope of protection extends to said computer program and further to computer readable means comprising a recorded message, said computer readable means comprising program coding means for carrying out one or more steps of the method, when said program is run on a computer. Implementation variants of the described non-limiting example are possible, without however departing from the scope of protection of the present invention, including all the equivalent embodiments for a person skilled in the art, to the content of the claims.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Operation Control Of Excavators (AREA)
EP23187382.9A 2022-07-25 2023-07-24 Procédé et système de commande d'un bras d'un véhicule de travail Pending EP4311887A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT202200015639 2022-07-25

Publications (1)

Publication Number Publication Date
EP4311887A1 true EP4311887A1 (fr) 2024-01-31

Family

ID=83438301

Family Applications (1)

Application Number Title Priority Date Filing Date
EP23187382.9A Pending EP4311887A1 (fr) 2022-07-25 2023-07-24 Procédé et système de commande d'un bras d'un véhicule de travail

Country Status (1)

Country Link
EP (1) EP4311887A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009256891A (ja) * 2008-04-14 2009-11-05 Caterpillar Japan Ltd クレーン機能付油圧ショベル
JP2011236562A (ja) * 2010-05-06 2011-11-24 Caterpillar Sarl 作業機械のフロント制御装置
US20200407945A1 (en) * 2018-03-22 2020-12-31 Sumitomo Heavy Industries, Ltd. Excavator

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009256891A (ja) * 2008-04-14 2009-11-05 Caterpillar Japan Ltd クレーン機能付油圧ショベル
JP2011236562A (ja) * 2010-05-06 2011-11-24 Caterpillar Sarl 作業機械のフロント制御装置
US20200407945A1 (en) * 2018-03-22 2020-12-31 Sumitomo Heavy Industries, Ltd. Excavator

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