Patent Application
20140324302
This patent disclosure relates generally to payload hauling machines, and, more particularly to methods of estimating the mass of carried by a payload hauling machine.
Hauling machines are utilized in various industries to transport a payload from one location to another. In order to operate such machines efficiently, it is desirable to carry an optimally sized payload. Loading a machine to less than full capacity may result excess costs associated with unnecessary runs and the acceleration of maintenance schedules. Overloading a machine may result in increased wear and costly maintenance.
Numerous methods have been proposed for determining the mass of payloads in hauling machines. While physically weighing a machine on a scale and then deducting the weight of the machine itself may be a reliable method of measuring a payload, such an arrangement is not practical in large machines. Moreover, physically weighing a machine is generally not possible in the field.
European Patent Application Publication 0 356 067 to Kirby discloses a method of calculating the mass of a vehicle utilizing the equation weight is equal to force divided by acceleration, that is, W=f/a, adjusted based upon calculations utilized to obtain the values for force and acceleration. Kirby proposes the measurement of acceleration based upon an inertial accelerometer, by measurements associated with a braking mechanism, or by the deformation or twisting of a drive train member measured by magnetic markers mounted a propeller shaft of a road vehicle. The twisting of the shaft results in a delay between signals from the markers, wherein the time interval is proportional to the accelerating force. Kirby further proposes that force be determined from a sensor arrangement in conjunction with a time signal from a speedometer arrangement wherein the machine is traveling on a level ground at a constant acceleration between two speeds. Kirby indicates that resulting constants in the calculation may be evaluated in a known weight machine and eliminated by calibration such that weight of the vehicle may be calculated using the above equation.
The disclosure describes, in one aspect, a method, implemented by a programmable controller in a hauling machine having moveable ground engaging elements and a bed. The method estimates a payload contained in the bed during forward movement of the machine. The method includes determining whether the machine is at a steady acceleration and grade, estimating transmission torque, calculating axle torque at at least one of the ground engaging elements, calculating force at said ground engaging element, determining the acceleration of the machine, calculating mass of the machine with the payload, adjusting the calculated mass of the machine with the payload based upon an estimated machine mass and rolling resistance, and providing an estimate of the mass of the payload.
The disclosure describes, in another aspect, a non-transitory computer- readable medium including computer-executable instructions facilitating performing a method, implemented by a programmable controller, of estimating a payload contained in a bed of a hauling machine having moveable ground engaging elements during forward movement of the machine. The method includes determining whether the machine is at a steady acceleration and grade, estimating transmission torque, calculating axle torque at at least one of the ground engaging elements, calculating force at said ground engaging element, determining the acceleration of the machine, calculating mass of the machine with the payload, adjusting the calculated mass of the machine with the payload based upon an estimated machine mass and rolling resistance, and providing dynamic payload estimate.
The disclosure describes, in yet another aspect, a hauling machine having a plurality of moveable ground engaging elements, a bed adapted to carry a payload, a transmission adapted to operate in a plurality of gears, an accelerometer adapted to indicate current operational status of the machine, and a programmable controller. The programmable controller is configured by computer-executable instructions to estimate a mass of a payload contained in the bed during forward movement of the machine using a set of parameters including: operational status of the transmission, length of time in the current gear, grade, throttle position, currently machine acceleration operational status, parameters of at least one ground engaging element, empty machine mass, and estimated rolling resistance.
While the appended claims set forth the features of the present invention with particularity, the invention and its advantages are best understood from the following detailed description taken in conjunction with the accompanying drawings, of which:
This disclosure relates to hauling machines and the determination of the mass of a carried payload.
Referring to
The rear frame portion 106 supports a bed 130. In the illustrated machine 100, the bed 130 may be selectively pivoted between a load position (illustrated) and an unload position (shown in phantom) by one or more hoist cylinders 132 in response to commands from operator hoist control 134 (see
The machine 100 may include additional operator controls, such as a throttle 136, and a transmission gear control 138 by which an operator may choose a particular gear from a given selection of gears (see
The controls and sensors provide signals indicative of the respective control or sensed feature to a programmable controller 156. During operation of the machine 100, the controller 156 may be configured to receive and process information relating to operation of the machine 100 and to provide a determination of the mass of a payload 133 carried by the machine 100 during dynamic operation by methods described with regard to
The controller 156 may include a processor (not shown) and a memory component (not shown). The processor may be microprocessors or other processors as known in the art. In some embodiments, the processor may be made up of multiple processors. Instructions associated with the methods described may be read into, incorporated into a computer readable medium, such as the memory component, or provided to an external processor. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions. Thus, embodiments are not limited to any specific combination of hardware circuitry and software.
The term “computer-readable medium” as used herein refers to any medium or combination of media that participates in providing instructions to processor for execution. Such a medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, optical or magnetic disks. Volatile media includes dynamic memory. Transmission media includes coaxial cables, copper wire and fiber optics.
Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, or any other magnetic medium, a CD-ROM, any other optical medium, punchcards, papertape, any other physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, any other memory chip or cartridge, or any other medium from which a computer or processor can read.
The memory component may include any form of computer-readable media as described above. The memory component may include multiple memory components.
The controller 156 may be a part of a control module may be enclosed in a single housing. In alternative embodiments, the control module may include a plurality of components operably connected and enclosed in a plurality of housings. In still other embodiments the control module may be located in single location or a plurality of operably connected locations including, for example, being fixedly attached to the machine 100 or remotely to the machine 100.
Turning now to
In order for the calculation of the estimated mass of the payload 133 during dynamic conditions to be valid, the machine 100 must be operating in a relatively high torque situation, and at or near a steady acceleration and grade. Referring to the strategy 300 as illustrated in
Referring to decision box 320, in order to reliably estimate the payload 133 during dynamic conditions, the controller 156 determines whether the transmission 126 is operating in a gear greater than a predetermined gear. Further, in order to ensure that the gear operation is not a transient operation, the controller 156 determines whether the transmission 126 has been maintained in that operating gear for at least a given period (see decision box 330). If either of these requirements is not satisfied, then estimation of the payload mass during dynamic conditions will not be considered reliable.
Information regarding the operation of the transmission 126 may be provided by any appropriate mechanism. For example, in some embodiments, the controller 156 directs operation of the transmission 126, including the operating gear utilized, and may include the determination of the time in a given gear. Additionally or alternatively, sensors or the like associated with the transmission 126 may provide signals indicative of the operating gear as well as time in that gear.
Referring to decision box 340, the controller 156 determines if the machine 100 is operating on a grade that is higher than a predetermined grade. By way of example only, an appropriate predetermined grade may be 6%. Grade may be determined by any appropriate mechanism. For example, a tilt sensor, inclinometer, or grade detector 150 may provide a signal indicative of the grade to the controller 156. Alternately, the grade may be calculated by any appropriate data, such as, for example, a calculation based upon a signal from an accelerometer. An estimation of the payload mass during dynamic conditions will be reliable only if the machine 100 is operating on at least a given grade.
Further, the machine 100 must be operating with the throttle in a position higher than a predetermined level in order for the estimation to be reliable. Throttle position may be determined by any appropriate mechanism. For example, a sensor may be provided, or the operator control for the throttle 136 may provide a signal indicative of the throttle position to the controller 156 from which the controller 156 may compare the throttle position to the predetermined level in order to determine if the resultant estimation of the payload mass during dynamic conditions will be reliable. An appropriate throttle position may be, for example, near full throttle.
Although not illustrated in
Turning to
As indicated in box 410, the output torque from the transmission 126 is estimated. The torque may be estimated or calculated by any appropriate method, device(s) or machine operating parameter values. For example, a dynamic estimator may utilize an engine torque signal broadcast by an engine ECM. The torque may be estimated based upon machine operating parameter values including reported engine torque, speed ratio (ratio of torque converter input to converter output), and engine speed. As indicated in box 415, the estimated torque from the transmission 126 may be filtered, applying a filter constant based upon the particulars of the machine 100 in order to obtain a signal indicative of the transmission torque.
As indicated at box 420, in order to calculate the torque applied at an axle 116 of wheel 112, the signal indicative of the transmission torque is multiplied by a force factor based upon transmission loss efficiency (box 425), and an axle ratio adjustment 430. The axle ratio adjustment 430 may be based upon a gear ratio to the axle 116. To determine the force (F) applied at the wheel 112 (see box 435), the torque applied at the axle 116 is divided by the radius 118 of the wheel 112 (see box 440).
An accelerometer 144 disposed at the bed 130 of the machine 100 is provides a signal indicative of acceleration in the X direction at the bed 130, that is, in the fore and aft direction. A filter constant is utilized to filter the signal from the accelerometer 144 to provide a filtered accelerometer signal (see box 445) indicative of acceleration (a).
The mass of the machine 100 including the payload 133 (box 445) is calculated by dividing the force (F) at the wheels 112 by the acceleration (a) based upon the filtered accelerometer signal (box 450). Adjustments are made to the calculated mass of the machine 100 with payload 133 (box 455) to account for the mass of the machine 100. An estimated mass of the unloaded machine 100 (box 460) is adjusted based upon estimated rolling resistance of the machine 100 and prior mass calculations (box 465) and subtracted from the estimated mass of the machine 100 including the payload 133 to provide an initial estimate of the mass of the dynamic payload 133. Other adjustments may likewise be made based upon specifics of the machine 100 and prior calculations of mass (box 470) to provide the final estimate of the mass of the dynamic payload 133 at box 475.
The strategy for estimating the dynamic mass of a payload 133 of a machine 100 may be a part of a larger strategy or integration algorithm for estimating the mass of a payload 133 of a machine 100. Turning to
More specifically, a strategy 510 for determining the mass of a carried payload 133 during dynamic conditions may be utilized to estimate the mass if it is detected at either decision box 540 or decision box 550 that the conditions exist for reliably determining a dynamic mass estimate. A strategy 300 such as is illustrated in
From the determination of a dynamic mass estimate (box 510), if emptying of the bed 130 is detected (decision box 560), the strategy 530 directed to an emptying event may be applied to determine whether the bed 130 is empty, there is no payload 133 contained in the bed 130. Conversely, if a load event is detected (decision box 570), the strategy 520 directed to a loading event may be applied to determine if a loading event is occurring.
Similarly, from the determination of a loading event by the strategy 520, if the conditions are detected for the reliable determination of a dynamic mass estimate (decision box 550), then the strategy 510 for the determination of the mass under dynamic conditions may be applied. Conversely, if an emptying event is detected (decision box 580), the strategy 530 directed to an emptying even may be applied to determine whether the bed 130 is empty.
Finally, from the determination of an emptying event by the strategy 530, if the conditions are detected for the reliable determination of a dynamic mass estimate (decision box 540), then the strategy 510 for the determination of the mass under dynamic conditions may be applied. Again, conversely, if a load event is detected (decision box 590), the strategy 520 directed to a loading event may be applied to determine if a loading event is occurring.
The integration strategy 500 of
From the information provided, individual strategies 620-623 may be applied for determining the reliability of a dynamic payload mass estimation, estimating a dynamic payload mass, emptying detection, and loading event detection. Again, an embodiment may further include any appropriate mechanism for providing an indication that all individual strategies are proceeding (box 630). From the operation of the individual strategies 620-623 along with the integration strategy (box 640) such as the integration strategy 500 illustrated in
Further, the estimated mass obtained may be utilized in the additional algorithms, as indicated by box 670, the mass correction loop. For example, an estimated mass of the machine 100 and payload 133 may be utilized in calculations and estimates related to the rolling resistance of the machine 100, as utilized in boxes 460 and 465 in the strategy illustrated in
The present disclosure is applicable to machines 100 including a bed 130 for carrying a payload 133. Embodiments of the disclosed strategy may have the ability to estimate payload mass without the use of any other weight sensors.
Some embodiments may take into account appropriate losses for one or more of the factors utilized to calculate an estimated force (F) at the wheels 105.
The strategy for calculating the mass of a dynamic payload 133 may be utilized at opportune times when the calculation will be accurate.
It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated.
The use of the terms “a” and “an” and “the” and “at least one” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context.
Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.
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 or otherwise clearly contradicted by context.
