EP1217128A1 - Système de gestion de puissance - Google Patents

Système de gestion de puissance Download PDF

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Publication number
EP1217128A1
EP1217128A1 EP01125680A EP01125680A EP1217128A1 EP 1217128 A1 EP1217128 A1 EP 1217128A1 EP 01125680 A EP01125680 A EP 01125680A EP 01125680 A EP01125680 A EP 01125680A EP 1217128 A1 EP1217128 A1 EP 1217128A1
Authority
EP
European Patent Office
Prior art keywords
power
implement
subsystem
speed
management controller
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Withdrawn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
EP01125680A
Other languages
German (de)
English (en)
Inventor
George T. Caterpillar Inc. Chiu
Matthew A. Caterpillar Inc. Franchek
Grant A. Caterpillar Inc. Ingram
Richard G. Caterpillar Inc. Ingram
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
Priority claimed from US09/894,357 external-priority patent/US6427107B1/en
Application filed by Caterpillar Inc filed Critical Caterpillar Inc
Publication of EP1217128A1 publication Critical patent/EP1217128A1/fr
Withdrawn legal-status Critical Current

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    • 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
    • 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
    • E02F9/2058—Electric or electro-mechanical or mechanical control devices of vehicle sub-units
    • E02F9/2062—Control of propulsion units
    • E02F9/2066—Control of propulsion units of the type combustion engines

Definitions

  • This invention relates generally to controlling power to the subsystems of a construction machine and particularly to distributing available power to the machine subsystems by using a power management controller responding to predetermined priorities and operational requirements.
  • the invention relates to the implement and drive train subsystems of a construction machine.
  • the available power typically provided by an internal combustion engine
  • the available power is mainly consumed by three major systems; namely, a power steering system, an implement control system and a power train system for propulsion.
  • a power steering system For safety reasons, it is typical for the steering system to be given first priority to available power.
  • the remaining power is available for consumption by the implement operating system and the power train system.
  • the wheel loader In operating a wheel loader to load rock in a raised hopper of a rock crusher, the wheel loader scoops up a bucket load of raw material and travels toward the hopper with the bucket relatively low in interest of visibility and machine stability.
  • some rock crusher hoppers are located on level ground, it is common practice to build a loading ramp to the hopper, the length and grade of which varies from site to site.
  • the operator raises the bucket in anticipation of dumping the load when the hopper is reached.
  • the implement operating system and the power train system are simultaneously consuming power.
  • U.S. Patent Number 6,047,545 issued 11 April 2000 to Horst Deininger for Hydrostatic Drive System discloses a lift truck power system in which a hydraulic steering system is given first priority, a hydraulic work system is given second priority and a hydrostatic drive system is given third priority.
  • This and other priority systems employed in wheel loaders give rise to the problem of excessively slow travel speed when traveling with a load of rock up a loading ramp to a rock crusher hopper and simultaneously raising the bucket in anticipation of dumping the raw material in the hopper.
  • U.S. Patent Number 5,295,353 issued 22 March 1994 to M. Ikari for a Controlling Arrangement for Travelling Work Vehicle illustrates and describes a wheel loader having a torque converter and two fixed capacity hydraulic pumps supplying pressure fluid to the valves controlling boom lift and bucket tile actuators.
  • One of the two hydraulic pumps is unloaded when the accelerator pedal is at full throttle and the engine speed is under a predetermined speed.
  • this control system provides a change in allocation of power when the engine does not increase speeds in response to a requested speed increase, the control does not provide for adjustment of the power allocations to the implement and power train subsystems based on the operator's desired commands.
  • the present invention is directed to overcoming one or more of the problems as set forth above.
  • the available power after satisfying vehicle steering requirements, is allocated to an implement subsystem and power train system.
  • the allocation of power to the implement subsystem and the power train subsystem is controlled by a power management system which is programmed to allocate a quantity of available power to the implement subsystem, such quantity falling between predetermined maximum and minimum percentages of the available power depending on the difference between desired travel speed and actual travel speed.
  • the maximum and minimum percentages of the available power allocated to the implement subsystem may be adjusted to provide efficient machine performance for particular machine work assignments. Adjustable set points are preferably provided to establish the minimum difference between the desired and the actual travel speed at which the maximum percent of available power is allocated to the implement subsystem and to establish the maximum difference in the desired and the actual travel speed at which the minimum percent of available power is allocated to the implement subsystem.
  • An on-board compute is programmed to provide a smooth change in power allocation to the implement subsystem as changes occur in the difference between requested travel speed and actual travel speed.
  • a wheel loader 11 is shown dumping rocks into a hopper 12 of a rock crusher.
  • the wheel loader 11 is equipped with an internal combustion engine 13 which drives a pair of front wheels 14, 16 and a pair of rear wheels 17, 18 through a power train subsystem 19 which includes a transmission 20.
  • the engine 13 also drives a pump 21 supplying hydraulic power to a steering subsystem 22 which includes a steering cylinder 23, and drives a variable displacement pump 24 supplying pressurized hydraulic fluid to implement lift and tilt valves, not shown, controlling a pair of cylinders 26, 27 and a tilt cylinder 28 of an implement subsystem 29.
  • variable displacement pump 24 When either of the control valves, not shown, for operating the lift and tilt cylinders 26, 27, 28, are shifted to a cylinder actuating position the variable displacement pump 24 is automatically stroked from neutral to a pressure fluid supplying condition, the displacement adjustment being dependent on the extend of the adjustment of the implement valve or valves.
  • the steering subsystem is given first priority to engine power.
  • the power left over, after satisfying the steering subsystem power requirements, is available for consumption by the implement and power train subsystems and is hereinafter referred to as calculated power available or available power.
  • a power management controller 36 on board the wheel loader 11 calculates the available power after deducting steering power being consumed and makes an allocation of the calculated power available to the implement subsystem 29. The remaining power is available for consumption by the power train subsystem 19.
  • the power management controller 36 is fed a signal such as a number indicative of the rated horse power of the engine 13 and a steering power signal, such as a number, based on desired cylinder speeds and pump pressure, which permit the power management controller 36 to calculate the power available (PA) for distribution to the implement and power train subsystems 29, 19.
  • a signal such as a number indicative of the rated horse power of the engine 13 and a steering power signal, such as a number, based on desired cylinder speeds and pump pressure, which permit the power management controller 36 to calculate the power available (PA) for distribution to the implement and power train subsystems 29, 19.
  • PA power available
  • Figure 3 shows the calculated power available divided between the implement and power train subsystems.
  • the fractional allocation ⁇ of available power to the implement subsystem 29 automatically determines the power allocation to the power train subsystem 19, represented by 1- ⁇ .
  • the power management controller 36 allocates power by changing the amount of pressurized fluid flowing to the implement subsystem control valves, not shown. This is done by the power management controller 36 changing the displacement of the variable displacement pump 24.
  • a power distribution algorithm is loaded into a computer in the power management controller 36 which programs the computer to cause the power management controller 36 to vary the allocation of power to the implement subsystem 29 in response to deficiencies in the actual travel speed as compared to the desired travel speed of the wheel loader.
  • a signal indicative of the desired travel speed is delivered to the power management controller 36 by a sensor, not shown, associated with a speed control, not shown, operated by the machine operator. For instance the sensor could sense displacement of an acceleration pedal.
  • An actual travel speed signal is delivered to the power management controller by a travel speed sensor associated with the power train subsystem 19. The travel speed sensor may sense the speed of the output shaft of the transmission of the power train subsystem 19, which is indicative of the actual travel speed of the wheel loader.
  • the operation of the power management controller 36 is illustrated in Figure 4.
  • the power management controller 36 is only active when a power limited condition is determined by the transmission controller. In the event the wheel loader 11 is power limited, the power available (PA) for allocation is calculated. In addition, the value of ⁇ and the operator's desired implement power are calculated by the power management controller 36.
  • the implement tilt and lift levers, not shown, associated with the operator's desired lift and tilt cylinder velocities delivers a signal to the power management controller 36 which is indicative of the desired power for the implement subsystem 29. If the desired implement power is less than the power allocated to the implement subsystem 29, then the power management controller 36 will not issue an implement subsystem power command.
  • the power consumed by the implement subsystem 29 will only be reduced if the operator is demanding more power for this subsystem than the power distribution algorithm would allocate. If the operator is demanding more power for the implement subsystem 29 than is allocated to the implement subsystem 29, the power management controller 36 (which changes the stroking of the variable displacement pump 29) will reduce the operator implement commands until the power consumed by the implement subsystem 29 is equal to the power allocated to that subsystem.
  • the power management controller 36 is programmed to provide power to the implement subsystem 29 between predetermined minimum ( ⁇ min) and maximum ( ⁇ max) fractions of the available power.
  • Figure 5 shows ⁇ as a function of the transmission speed error in accordance with the before mentioned equation.
  • the ⁇ as a function of the transmission speed error in accordance with the before mentioned equation.
  • the ⁇ scheduling function has three segments. The first segment extends from zero to a ⁇ max setpoint. The second segment is a transition lying between the ⁇ max setpoint and a ⁇ min setpoint where the value of ⁇ ranges from ⁇ max to ⁇ min.
  • the third segment of the curve extends beyond the ⁇ min setpoint where ⁇ is a fixed value of ⁇ min.
  • ⁇ is a fixed value of ⁇ min.
  • the third order polynomial expression, 1 - 3x2 + 2x3 is part of the equation for the curve of Figure 5 and also the later discussed curves shown in Figures 6-9.
  • ⁇ scheduling function There are four parameters which define the ⁇ scheduling function; (1) ⁇ max, (2) ⁇ min, (3) ⁇ max setpoint, and (4) ⁇ min setpoint. Each parameter has physical meaning and can be specified based on operator perception.
  • the maximum value of ⁇ , ( ⁇ max), represents the maximum fraction of power available to the implement subsystem.
  • the parameter ⁇ max also determines the minimum fraction of power available for the power train subsystem 19.
  • ⁇ min represents the minimum fraction of power available for the implement subsystem 29 and determines the maximum fraction of power available for the power train subsystem 19.
  • the values of the parameters entered into the computer program are normally based on the transmission speed error incurred at a particular job site.
  • the smallest transmission speed error selected for a given site may also depend on the programmed values of ⁇ max and ⁇ min.
  • the largest transmission speed error selected for a given site is dependent on the values given ⁇ max and ⁇ min.
  • These parameters also affect the sensitivity of the function ⁇ .
  • the function ⁇ may become too sensitive to changes in transmission speed error when transitioning between ⁇ max ⁇ min over a short interval. In these cases, power may be distributed erratically due to fluctuations in transmission speed error. For this reason ⁇ max setpoint and ⁇ min setpoint must be chosen such that ⁇ is not significantly affected by normal fluctuations or transmission speed error.
  • Figure 8 shows the values of ⁇ with reduced ⁇ max setpoint and ⁇ min setpoint values.
  • the power management controller 36 delivers the programmed maximum fraction ( ⁇ max) of available power to the implement subsystem 29 until the absolute value of the difference between the requested (desired) and actual power train speed rises to a predetermined RPM ( ⁇ max setpoint)
  • the power management controller 36 delivers a predetermined minimum fraction ( ⁇ min) of the available power to the implement subsystem 29 upon the absolute value of the difference between the requested speed and the delivered speed exceeding a predetermined RPM.
  • Figure 7 shows the same ⁇ max and ⁇ min setpoints as used in Figure 5; however, the ⁇ max and ⁇ min values have been increased and thus the portion or fraction of available power allocated to the implement subsystem 29 has been increased, and, consequently, less power is available for the power train subsystem 19 than was available when the power management controller 36 controlled power allocation according to the curve of Figure. 5.
  • Figure 6 shows the ⁇ max and ⁇ min values adjusted up and down, respectively. As compared to Figure 5, more implement subsystem 29 power (and less power to the power train subsystem 19) is allocated in the first section of the allocation curve and less implement subsystem power 29 is allocated than in Figure 5 in the third section of the allocation curve.
  • Figure 9 shows the operating curve of power allocation to the implement subsystem 29 with the ⁇ max and ⁇ min settings the same as in Figure 5 but with changes in the ⁇ max setpoint and the ⁇ min setpoint.
  • the allocation of power ( ⁇ ) to the implement subsystem 29 begins to be reduced at a rather low ⁇ max setpoint and reduction continues to a rather high ⁇ min setpoint.
  • Figure 10 is a block diagram of the power management system of this invention in an engine powered vehicle having power consuming steering, implement and power train subsystems.
  • the power management controller herein described is programmed to allocate quantities of power to the implement power subsystem 29 between maximum and minimum fractions ( ⁇ ) of the available power dependent on the transmission speed error.
  • Transmission speed error is the absolute value of the difference between the desired speed and the actual transmission speed.
  • the chosen maximum and minimum allocations ( ⁇ max, ⁇ min) of available power to the implement subsystem 29 are input into the computer of the power management controller together with ⁇ max setpoint and ⁇ min setpoint values. These parameters are selected and input into the computer to provide efficient machine operation for a particular work function and/or particular work site. In wheel loader applications, such as loading rock in the illustrated rock crusher hopper 12, maintaining a reasonable travel speed while raising the bucket in preparation for the dumping of the raw material into the hopper, is necessary to achieve good loader productivity.
  • Each of the four parameters ( ⁇ max, ⁇ min, ⁇ max setpoint, ⁇ min set point) of the ⁇ scheduling function may be chosen and entered into the computer in response to operator preferences or feedback. These parameters allow for a customized power distribution in the construction machine for any operator and/or for any particular work site. For example, one operator may perceive excessively slow travel speed while lifting a full bucket as a power limitation. Another operator may perceive power limitation from observing slow implement responses. In either case, the parameters of the ⁇ scheduling function may be set independently for each operator such that the power limitations of the wheel loader are not readily perceivable. Furthermore, the parameters that define the function of ⁇ have physical meaning. This allows for easier tuning in the field.
  • This invention provides flexibility in the distribution of power in construction machinery based on the perception of power limited modes by any operator.
  • this power management controller is applied to wheel loaders there is an important additional benefit of reducing the cycle time required for loading and dumping operations, such as loading rock crusher hoppers.

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Operation Control Of Excavators (AREA)
  • Power Steering Mechanism (AREA)
EP01125680A 2000-12-22 2001-10-26 Système de gestion de puissance Withdrawn EP1217128A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US25806000P 2000-12-22 2000-12-22
US258060P 2000-12-22
US09/894,357 US6427107B1 (en) 2001-06-28 2001-06-28 Power management system and method
US894357 2001-06-28

Publications (1)

Publication Number Publication Date
EP1217128A1 true EP1217128A1 (fr) 2002-06-26

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EP01125680A Withdrawn EP1217128A1 (fr) 2000-12-22 2001-10-26 Système de gestion de puissance

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EP (1) EP1217128A1 (fr)
JP (1) JP4060584B2 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8548713B2 (en) 2008-07-24 2013-10-01 Rolls-Royce Plc Power demand management
EP3318681A1 (fr) * 2016-11-08 2018-05-09 Guangxi LiuGong Machinery Co., Ltd. Anti-calage d' uvres hydrauliques à niveaux multiples
CN111656630A (zh) * 2018-02-07 2020-09-11 Ls电气株式会社 配电盘的监测及负载控制系统

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5214916A (en) * 1992-01-13 1993-06-01 Caterpillar Inc. Control system for a hydraulic work vehicle
US5295353A (en) 1990-06-06 1994-03-22 Kabushiki Kaisha Komatsu Seisakusho Controlling arrangement for travelling work vehicle
US5297649A (en) * 1988-08-23 1994-03-29 Shigeru Yamamoto Apparatus for controlling output from engine on crawler type tractor
US5525043A (en) 1993-12-23 1996-06-11 Caterpillar Inc. Hydraulic power control system
US5737993A (en) * 1996-06-24 1998-04-14 Caterpillar Inc. Method and apparatus for controlling an implement of a work machine
US5996701A (en) * 1997-12-19 1999-12-07 Komatsu Ltd. Control method and system for construction machine
US6047545A (en) 1997-09-24 2000-04-11 Linde Aktiengesellschaft Hydrostatic drive system

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5297649A (en) * 1988-08-23 1994-03-29 Shigeru Yamamoto Apparatus for controlling output from engine on crawler type tractor
US5295353A (en) 1990-06-06 1994-03-22 Kabushiki Kaisha Komatsu Seisakusho Controlling arrangement for travelling work vehicle
US5214916A (en) * 1992-01-13 1993-06-01 Caterpillar Inc. Control system for a hydraulic work vehicle
US5525043A (en) 1993-12-23 1996-06-11 Caterpillar Inc. Hydraulic power control system
US5737993A (en) * 1996-06-24 1998-04-14 Caterpillar Inc. Method and apparatus for controlling an implement of a work machine
US6047545A (en) 1997-09-24 2000-04-11 Linde Aktiengesellschaft Hydrostatic drive system
US5996701A (en) * 1997-12-19 1999-12-07 Komatsu Ltd. Control method and system for construction machine

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8548713B2 (en) 2008-07-24 2013-10-01 Rolls-Royce Plc Power demand management
EP3318681A1 (fr) * 2016-11-08 2018-05-09 Guangxi LiuGong Machinery Co., Ltd. Anti-calage d' uvres hydrauliques à niveaux multiples
US10619330B2 (en) 2016-11-08 2020-04-14 Guangxi Liugong Machinery Co., Ltd. Multiple level work hydraulics anti-stall
CN111656630A (zh) * 2018-02-07 2020-09-11 Ls电气株式会社 配电盘的监测及负载控制系统
CN111656630B (zh) * 2018-02-07 2022-03-22 Ls电气株式会社 配电盘的监测及负载控制系统

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Publication number Publication date
JP2002317470A (ja) 2002-10-31
JP4060584B2 (ja) 2008-03-12

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