WO2014201131A1

WO2014201131A1 - Method and apparatus for computing payload weight

Info

Publication number: WO2014201131A1
Application number: PCT/US2014/041937
Authority: WO
Inventors: Pierre Barriol; Frederic HEBRARD DE VEYRINAS
Original assignee: Caterpillar Inc.
Priority date: 2013-06-11
Filing date: 2014-06-11
Publication date: 2014-12-18
Also published as: GB201310375D0; GB2515033A

Abstract

A method of computing payload weight in a payload carrier is disclosed. The payload carrier may be movably supported on a construction vehicle. The method may comprise the steps of measuring raise rate of an empty lift; loading the payload carrier with a payload; measuring raise rate of the loaded lift; comparing the raise rate of the empty lift to the raise rate of the loaded lift; and computing payload weight.

Description

METHOD AND APPARATUS FOR COMPUTING PAYLOAD WEIGHT

Technical Field

This disclosure relates generally to vehicles having an articulated arm for transferring payload material and, more particularly, to a method and apparatus for computing and indicating the weight of the payload material being transferred.

Background

Construction vehicles may be used to transfer payload material, such as aggregate construction or mining material. The payload material may be moved, from one place, such as a pile of stored material, to another, such as a truck used for hauling the material to another location.

The construction vehicles may be typically loaders, excavators or telehandlers, which are wheeled or tracked vehicles having an articulated arm with an excavation or a loading tool. The construction vehicles may include hydraulics or other mechanisms for raising, lowering and tilting the tool. The articulated arm may be hydraulically controlled and may follow a modifiable trajectory. The tool such as a bucket or lifting fork, may also be hydraulically controlled in an angular position.

The construction vehicles may be stationary and also capable of moving payload material. Generally, a loader may be any vehicle capable of using a bucket or other appropriate payload carrier to transport payload material.

Information relating to the payload material, including the desired type and amount of payload material may need to be communicated to the operators of the loaders. Payload material weight measurement may be a desirable information for improving hauling operation productivity and safety.

US20100161184 discloses an apparatus for determining the weight of a payload in a bucket of a machine where the bucket is attached to a chassis of the machine by a linkage. The apparatus comprises an energy storage device for storing potential energy of the bucket, payload, and linkage when the bucket is moved from a first suspended position to a second suspended position. A mechanism provides physical data corresponding to a physical change in the energy storage device caused by storage of the potential energy and a processor calculates the weight of the payload using the physical data.

The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of the prior art system.

Brief Summary of the Invention

In a first aspect, the present disclosure describes a method of computing payload weight in a payload carrier movably supported on a construction vehicle, the method comprising the steps of: measuring raise rate of an empty lift; loading the payload carrier with a payload; measuring raise rate of the loaded lift; comparing the raise rate of the empty lift to the raise rate of the loaded lift; and computing payload weight.

In a second aspect, the present disclosure describes a method of assessing safety of a payload weight in a payload carrier movably supported on a construction vehicle, the method comprising the steps of: performing the method of computing payload weight; and emitting a warning when the height of the loaded payload carrier exceeds a predetermined height for a respective payload weight.

Brief Description of the Drawings

The foregoing and other features and advantages of the present disclosure will be more fully understood from the following description of various embodiments, when read together with the accompanying drawings, in which:

Fig. 1 is a side view of a construction vehicle according to the present disclosure; and

Fig. 2 is a flow chart for the estimation of payload weight according to the present disclosure. Detailed Description

This disclosure generally relates to payload weight estimation in a construction vehicle. FIG. 1 shows the construction vehicle 10 as a track-type loader. Although a track type loader is disclosed, the present disclosure may be applicable to construction vehicles such as wheeled type loaders, and other vehicles having similar loading implements.

The construction vehicle 10 includes a vehicle portion 12 connected with an implement portion 14. Implement portion 14 may have a payload carrier 16. Payload carrier 16 may be a bucket, lift forks or a tool that may be used to lift and transport a load, for example a grapple or a truss hook. Payload carrier 16 may be located on the front side or the rear side of the vehicle portion 12.

The vehicle portion 12 may have a chassis 18 that serves as a supporting frame for the vehicle portion 12. The chassis 18 may support various structures and components of the vehicle portion 12. Chassis 18 may either, directly or indirectly, support the engine, body panels and hydraulic system. The chassis 18 may also support continuous tracks 20 on opposite lateral sides thereof. Vehicle portion 12 may include a cab 22 supported on the chassis 18. Cab 22 may be an enclosed structure having windows 25.

The implement portion 14 may comprise a pair of parallel lift arms 24. In an embodiment, the payload carrier 16 may be attached to the vehicle portion 12 through the implement portion 14 that comprises the pair of lift arms 24. The lift arms 24 may extend between a rear portion of the payload carrier 16 to a position on the vehicle portion 12, such as at a location immediately in front of the cab 22. Lift arms 24 may be connected to the vehicle portion 12 by a pair of pivots at lift arm pivot points 32.

In an embodiment, the implement portion 14 may have a single lift arm 24 as in a telehandler or a loader having a boom box lift arm. In an embodiment, the payload carrier 16 may be attached to the vehicle portion 12 through the implement portion 14 that comprises a single lift arm 24. The lift arm 24 may extend between a rear portion of the payload carrier 16 to a position on the vehicle portion 12, such as at a location immediately in front of the cab 22. Lift arm 24 may be connected to the vehicle portion 12 by a pivot at a single lift arm pivot point 32.

A pair of lift arms 24 may be driven by a pair of respective lift cylinders 26. For each lift arm 24, a lift cylinder 26 may be pivotally attached to the vehicle portion 12 below the pair of lift arm pivot points 32. The lift cylinders 26 may be pivotally attached at lift cylinder pivot points 42 on the vehicle portion 12. The lift cylinder 26 may be pivotally attached to the lift arm 24 by a pivot at a pivot point 31 between the payload carrier 16 and a location of attachment of the lift arm 24 to the vehicle portion 12.

In the following disclosure references to lift arms 24 may be applicable to a single lift arm 24 with the required modification. For example, a single lift arm 24 may be driven by a single lift cylinder 26.

In an embodiment, the lift cylinder 26 may be a hydraulic cylinder having a rod 27 movably enclosed in a casing 29. The rod 27 may be able to extend from or retract into the casing 29 so as to pivot the respective lift arm 24 about the respective lift arm pivot points 32 on the vehicle portion 12. Each lift arm 24 may be rotated about the lift arm pivot point 32 relative to the vehicle portion 12 by the respective lift cylinder 26. The rotation of the lift arms 24 may move the payload carrier 16 thereby raising or lowering the payload carrier 16. The payload carrier 16 may be rotated as lift arm 24 is rotated. In general, any actuator or other mechanism capable of lifting the lift arms 24 may be used as an alternative to or in addition to the lift cylinders 26.

In an embodiment, the payload carrier 16 may further have a linear movement with construction vehicles 10 such as a telehandler. The payload carrier 16 may be moved in a linear direction when the lift arm 16 is being extended or retracted. Payload carrier 16 may have an additional linear movement while being raised or lowered.

Payload carrier 16 may be pivotally connected to lift arms 24 through pivot pins at payload carrier pivot points 28. The payload carrier 16 may be rotated about the pair of payload carrier pivot points 28. The payload carrier 16 may be pivotally movable between a dump position and a fully racked back position.

In an embodiment, payload carrier 16 may be additionally connected to the lift arms 24 through a tilt linkage 33, which determines the angular position of the payload carrier 16 relative to the vehicle portion 12 and/ or the lift arms 24. The tilt linkage 33 may have a major tilt arm 35 and a minor tilt arm (not shown). Major tilt arm 35 may be an elongate structure rotatably connected at a middle portion to a first cross member (not shown) extending horizontally between corresponding middle portions of the lift arms 24. The cross member may be rotatably connected to the lift arms 24.

A tilt cylinder 30 or other actuator may be provided to actuate the angular position of the payload carrier 16. Tilt cylinder 30 may connect an upper end of the major tilt arm 35 to a second cross member (not shown) that extends between the lift arms 24 adjacent the lift arm pivot points 32. The tilt cylinder 30 may be a hydraulic actuator having a rod 37 movably enclosed in an enclosure 39. The rod 37 may be able to extend from or retract into the enclosure 39 so as to rotate the major tilt arm 35 about the connection to the first cross member. The end of the major tilt arm 35, opposite the end connected to the tilt cylinder 30, may be connected to the payload carrier 16 through the minor tilt arm. The minor tilt arm may be an elongate structure having a tilt pivotal connection 38 to a rear portion of the payload carrier 16. In an embodiment, the tilt pivotal connection 38 may be located above the payload carrier pivot points 28. In an embodiment, the tilt cylinder 30 may extend so that, through the tilt linkage 33, the payload carrier 16 may rotate in an anticlockwise direction about the payload carrier pivot pins 28. The lower front edge 40 of the payload carrier 16 may rotate upwardly relative to vehicle portion 12. The tilt cylinder 30 may retract so that, through the tilt linkage 33, the payload carrier 16 may rotate in a clockwise direction about the payload carrier pivot pins 28. The lower front edge 40 of the payload carrier 16 may rotate downwardly relative to vehicle portion 12.

Payload carrier 16 may be made from metal and may have a substantially concave enclosure with a payload carrier opening 34 located away from the vehicle portion 12. In an embodiment, payload carrier 16 may comprise two parts movable relative to each other. In general, payload carrier 16 may have any shape capable of holding and lifting a payload.

A sensor device 36 may be positioned on the construction vehicle 10 for measuring raise rate of the implement portion 14. Sensor device 36 may be positioned on the vehicle portion 12. Sensor device 36 may be positioned on the articulated components of the construction vehicle 10. Sensor device 36 may be positioned on the implement portion 14. The sensor device 36 may be positioned on at least one lift arm 24 or the payload carrier 16. At least one sensor device 36 may be provided to measure raise rate of an empty lift and raise rate of a loaded lift. An empty lift may be defined as the rise of the implement portion 14 or components thereof without a payload. A loaded lift may be defined as the rise of the implement portion 14 or components thereof with a payload. The payload may be any material contained in the payload carrier 16. The raise rate may be defined as the time taken for the implement portion 14 to perform either an empty lift or a loaded lift. In an embodiment, a plurality of sensor devices 36 may be provided to measure raise rate of an empty lift and raise rate of a loaded lift.

In an embodiment, a plurality of sensor devices 36 may be positioned on the construction vehicle 10 for measuring raise rate of the implement portion 14 or components thereof. In an embodiment, sensor devices 36 may positioned on the vehicle portion 12 and/ or the implement portion 14. Sensor devices 36 may be positioned on a lift arm 24 and/ or the payload carrier 16. With respect to forgoing embodiments, the sensor devices 36 may be, in addition, positioned on both lift arms 24.

The sensor device 36 may transmit data through a wireless signal, for example via a radio signal or an infrared signal. The wireless signal may be preferably effected in a very short transmission time. The transmission time can be mutually synchronised for a plurality of sensor devices 36.

The sensor devices 36 may be powered by a power source, for example a battery. The power source may comprise energy harvesting technologies, for example a solar panel or harvesting energy from machine vibrations and stored in a battery. In an embodiment, sensor device 36 may be powered through a direct wiring from machine electrical power. An auxiliary power source may be provided as a backup power source. The auxiliary power source may be a battery.

Sensor device 36 may be provided with attachment members (not shown) for fixing onto construction vehicle 10. The attachment members may hold the sensor device 36 against the surface of the vehicle portion 12 or the implement portion 14. The attachment members may enable removable attachment of the sensor device 36. Each sensor device 36 may be independent and may be mounted in a manner that is independent of any other equipment on the receiving support surface.

At least one sensor device 36 may be positioned on the construction vehicle 10. Sensor device 36 may be positioned to measure the raise rate of the payload carrier 16. In an embodiment, sensor device 36 may be positioned to measure the raise rate of the lift arm 24 supporting the payload carrier 16. The sensor device 36 may be an accelerometer, a gyroscope and/or a magnetometers (IMU - Inertial Measurement Unit).

In an embodiment, a plurality of sensor devices 36 may be positioned on the construction vehicle 10 to measure the raise rate of the payload carrier 16. In an embodiment, a plurality of sensor devices 36 may be positioned on the construction vehicle 10 to measure the raise rate of the lift arm 24 supporting the payload carrier 16.

Sensor device 36 may be configured to detect the velocity such as angular velocity and/ or acceleration of the empty lift or the loaded lift of the implement portion 14. Sensor device 36 may be configured to detect the velocity and/ or acceleration of the empty lift or the loaded lift of at least one lift arm 24 and/ or the payload carrier 16.

In an embodiment, a plurality of sensor devices 36 may be provided to detect the velocity and/ or acceleration of the empty lift or the loaded lift of the implement portion 14. A plurality of sensor devices 36 may be provided to detect the velocity and/ or acceleration of the empty lift or the loaded lift of at least one lift arm 24 and/ or the payload carrier 16.

Sensor device 36 may be configured to detect the angles of at least one lift arm 24 and the payload carrier 16. In an embodiment, the angles may be computed from velocity or acceleration of the empty lift or the loaded lift of the implement portion 14. Sensor device 36 may detect the angle of at least one lift arm 24 relative to the vehicle portion 12, for example the chassis 18. Sensor device 36 may detect the angle of the payload carrier 16 relative to the vehicle portion 12, for example the chassis 18 and/ or at least one lift arm 24. The position of the lift arm 24 and/ or the payload carrier 16 may be determined from the detected angles. Detection of the angles may enable the operator to lift the payload carrier 16 flat. In an embodiment, a plurality of sensor devices 36 may be configured to detect the aforementioned angles.

A processor (not shown) may be configured to receive data from the at least one sensor device 36 and to compare the raise rate of the empty lift to the raise rate of the loaded lift for computing payload weight. In an embodiment, the processor may be configured to receive data from a plurality of sensor devices 36. In an embodiment, the payload weight may be computed on the basis of further machine inputs. Machine inputs may be parameters such as engine speed, travel speed.

In an embodiment, the length of the lift arm 24 or the raise distance may be a parameter, in particular when the lift arm 24 may be of the extendible type such as the arm of a telehandler. The length of the lift arm 24 or the raise distance may be determined by a height detector located on the lift arm 24. In an embodiment, the height of the lift arm 24 or the raise distance may be calculated by the processor on the basis of other machine inputs.

The processor may be configured to send the data relating to the estimated payload weight to a device (not shown) provided in the cab 22 for communication to the operator of the construction vehicle. The device may be a display for visual communication or a speaker for aural communication.

The data transmitted by the sensor device 36 may be processed by the processor that is positioned on the construction vehicle 10. The sensor device 36 may comprise a wireless communication module configured to send data to a wireless communication receiver (not shown) which sends the data to the processor. The processor and the wireless communication receiver may be powered by a power source provided in the cab 22. The wireless receiver may be configured to receive data via radio or infrared signal transmission.

The processor may be configured to receive data relating to the engine speed. In an embodiment, a sensor (not shown) may be positioned to monitor the engine speed. The processor may be configured to compute hydraulic power from the engine speed.

The processor may be configured to monitor for an operator input signal prior to measuring raise rate of an empty lift. In an embodiment, a sensor (not shown) may be provided to monitor for an operator input signal. The operator input signal may be a raise command.

In an embodiment, the raise command may be of an extended duration which does not include a short duration raise command such as a command for a quick raise to loosen payload material. In an embodiment, the extended raise command may be a raise command lasting for more than Is.

The processor may be configured to compare the estimated payload weight to a predetermined weight limit. The predetermined weight limit may be provided as a preprogramed data. In an embodiment, the predetermined weight limit may be pro vided as an operator input during work operations. The processor may be configured to emit a warning signal if the predetermined weight limit is exceeded by the estimated payload weight.

A method of computing payload weight in the payload carrier 16 that is movably supported on the construction vehicle 10 is herein described. The payload weight estimation may be performed according to a payload weight estimation algorithm as shown in Fig. 2. Payload weight is estimated through lifting movements of the implement portion 14.

The method of computing payload weight may involve a single lifting movement between reference points selected so as to detect and measure the raise rate of the implement portion 14 by the sensor device 36. The raise rate data obtained by the sensor device 36 may be sent to the processor which is configured to perform the payload weight estimation algorithm.

The method may comprise measuring the raise rate of an empty lift. The empty lift may be performed within a detection zone of the sensor device 36. The empty lift may be performed over a predetermined vertical distance. The empty lift may be performed over a predetermined angular distance relative to the vehicle portion 12, for example about the lift arm pivot point 32. The raise rate of the empty lift may determine the weight of the implement portion 14 when the payload carrier 16 is unloaded.

The measurement of an empty lift may be an initial calibration step. The estimation of payload weight for subsequent payload material may be performed by comparison with the initial calibration step. The raise rate of subsequent loaded lifts may be compared to the initial calibration empty lift. The calibration step may be repeated when required.

Upon completion of the calibration step the payload carrier 16 may be loaded with a payload. The payload may be payload material excavated from the ground, obtained from a stock pile or obtained from a loaded truck.

The method may further comprise measuring raise rate of the loaded lift. The loaded lift may be performed within a detection zone of the sensor device 36. The loaded lift may be performed over a predetermined vertical distance. The loaded lift may be performed over a predetermined angular distance relative to the vehicle portion 12, for example about the lift arm pivot point 32 or relative to the lift arm 24, for example about the pivot pins 28 connecting the lift arm 24 to the payload carrier 16. The estimated payload weight may be communicated to the operator through a visual display or a speaker.

The method may further comprise comparing the raise rate of the empty lift to the raise rate of the loaded lift. The data relating to the empty lift raise rate and the loaded lift raise rate may be sent to the processor. The processor may perform the comparison step and estimate the payload weight.

The method may be implemented by measuring the raise rate of the payload carrier 16. In an embodiment, the method may be implemented by measuring the raise rate of a lift arm 24 supporting the payload carrier 16. The method may involve measuring velocity or acceleration as the raise rate.

The method may further comprise the step of monitoring engine speed. Engine speed may be monitored by a sensor and the data may be sent to the processor. The processor may then compute hydraulic power from the engine speed.

The method may be implemented by monitoring for an operator input signal prior to measuring raise rate of an empty lift. The operator input signal may be a raise command.

The method may further comprise the step of comparing the estimated payload weight to a predetermined weight limit and emitting a warning signal if the predetermined weight limit is exceeded.

The method may further comprise the step of calculating the average payload weight of the payload material from a series of loaded lifts. The method may further comprise the step of calculating the cumulative payload weight of the payload material from a series of loaded lifts. The average and/ or cumulative weight may be communicated to the operator through a visual display or a speaker.

A method of assessing safety of a payload weight in a payload carrier 16 movably supported on a construction vehicle 10 may comprise at least the following steps to estimate payload weight: measuring raise rate of an empty lift; loading the payload carrier with a payload; measuring raise rate of the loaded lift; comparing the raise rate of the empty lift to the raise rate of the loaded lift; and computing payload weight. The method of assessing safety of a payload weight may further include the method steps described above with respect to payload weight estimation.

The method of assessing safety of a payload weight may further comprise the step of emitting a warning when the height of the loaded payload carrier exceeds a predetermined height for a respective payload weight. The processor may be preprogramed with data relating to various height limits for specific payload weights.

In an embodiment, the method may be implemented when the construction vehicle 10 is on an inclined plane, such as an uphill slope or a downhill slope. The construction vehicle 10 may operate on a plane tilted at an angle from the horizontal. The tilt angle of the construction vehicle 10 may be determined using sensors, for example an angle sensor that may be mounted on the chassis 18. The data relating to the tilt angle may be sent to the processor, for example by a wireless transmission. The tilt angle may be taken into account by the processor when performing the payload weight estimation algorithm.

The method of assessing safety of a payload weight may further comprise monitoring the tilt angle of the construction vehicle 10 and emitting the warning signal when the height of the loaded payload carrier exceeds a predetermined height for a respective payload weight at a respective tilt angle.

The skilled person would appreciate that foregoing embodiments may be modified or combined to obtain the method and apparatus of the present disclosure.

Industrial Applicability

This disclosure describes a method for computing the payload weight of payload material that is contained in the payload carrier 16. The disclosure also describes an apparatus for implementing the method of computing the payload weight of payload material contained in the payload carrier 16. The apparatus may be provided in a construction vehicle 10 such as a track loader, wheel loader or excavator.

The method and the apparatus permit the required amount of payload to be loaded onto a truck or deposited at a specific location. The present disclosure provides a method and an apparatus to estimate payload weight with accuracy and repeatability so that loading or deposit operations may be performed with efficiency through accurate truck loadings or site deposits. The method may be performed without the operator having to perform any specific command or sequence. The method may also provide efficiency of fuel and time.

Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein.

Where technical features mentioned in any claim are followed by reference signs, the reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, neither the reference signs nor their absence have any limiting effect on the technical features as described above or on the scope of any claim elements.

One skilled in the art will realise the disclosure may be embodied in other specific forms without departing from the disclosure or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting of the disclosure described herein. Scope of the invention is thus indicated by the appended claims, rather than the foregoing description, and all changes that come within the meaning and range of equivalence of the claims are therefore intended to be embraced therein.

Claims

1. A method of computing payload weight in a payload carrier (16) movably supported on a construction vehicle (10), the method comprising the steps of:

measuring raise rate of an empty lift;

loading the payload carrier (16) with a payload;

measuring raise rate of a loaded lift;

comparing the raise rate of the empty lift to the raise rate of the loaded lift; and computing payload weight.

2. The method of claim 1 wherein the raise rate of the payload carrier (16) is measured.

3. The method of claim 1 wherein the raise rate of a lift arm (24) supporting the payload carrier (16) is measured.

4. The method of claim 1 , 2 or 3 further comprising the step of monitoring engine speed.

5. The method of claim 4 comprising the step of computing hydraulic power from the engine speed.

6. The method of any one of preceding claims further comprising the step of monitoring for an operator input signal prior to measuring raise rate of an empty lift.

7. The method of claim 6 wherein the operator input signal is a raise command.

8. The method of any one of preceding claims further comprising the steps of comparing the estimated payload weight to a predetermined weight limit and emitting a warning signal if the predetermined weight limit is exceeded.

9. The method of any one of preceding claims wherein raise rate is velocity or acceleration.

10. A method of assessing safety of a payload weight in a payload earner (16) movably supported on a construction vehicle (10), the method comprising the steps of:

performing the method of computing payload weight of any one of preceding claims; and

emitting a warning when the height of the loaded payload carrier (16) exceeds a predetermined height for a respective payload weight.

11. The method of claim 10 further comprising monitoring the tilt angle of the construction vehicle (10) and emitting the warning signal when the height of the loaded payload carrier (16) exceeds a predetermined height for a respective payload weight at a respective tilt angle.

12. An apparatus for computing payload weight in a payload carrier (16) movably supported on a construction vehicle (10), the apparatus comprising:

at least one sensor device (36) to measure raise rate of an empty lift and raise rate of a loaded lift; and

a processor configured to receive data from the at least one sensor device (36) and to compare the raise rate of the empty lift to the raise rate of the loaded lift for computing payload weight.

13. The apparatus of claim 12 wherein the sensor device (36) is positioned to measure the raise rate of the payload carrier (16).

14. The apparatus of claim 12 wherein the sensor device (36) is positioned to measure the raise rate of the lift arm (24) supporting the payload carrier (16).

15. The apparatus of claim 12, 13 or 14 wherein the processor is further configured to monitor engine speed and to compute hydraulic power from the engine speed.