Machine system operation and control strategy for material supply and placement

A method of operating machine system includes receiving expected material placement data for a paving machine and comparing the expected material placement data with actual material placement data. The method further includes outputting a signal based on the comparison, and commanding replenishing material from a supply machine to the second supply volume responsive to the signal. A paving control system for a paving system includes a computer readable memory configured to store expected material placement data, a receiver configured to receive actual material placement data and a data processor configured to output a control signal to a supply machine to controllably replenish material to an external material supply volume for the paving system in a manner responsive to comparing the expected material placement data with the actual material replacement data.

TECHNICAL FIELD

The present disclosure relates generally to machine system operating and control strategies for supplying and placing material at a work site, and relates more particularly to controlling replenishing a material supply volume for the machine system responsive to a comparison between expected material placement data and actual material placement data.

BACKGROUND

In construction, road building and other industries, machine systems are often used to controllably place material to be used as a supporting substrate. In the context of paving roads, parking lots, etc., a paving machine is typically used to deposit and preliminarily compact a paving material which is later treated via one or more compacting machines to render a relatively hard, smooth traffic-bearing surface. A conventional paving machine includes a material storage hopper, a conveyor to transport material within the paving machine and a material placement mechanism such as a screed apparatus which controls a thickness and width of paving material deposited onto a work surface. For most jobs, the storage capacity of the hopper is insufficient to store all the paving material which will be placed by the paving machine. It is thus typically necessary to resupply the paving machine with material to be deposited such as asphalt, concrete or aggregate materials, periodically or continuously during operation.

To this end, many paving systems include supply machines which deposit material ahead of a paving machine on a surface to be paved. The paving machine may be equipped with or accompanied by a mechanism for loading the hopper with the material placed on the surface. One known system utilizes a mechanism known as a windrow elevator to elevate paving material deposited onto the surface in a windrow into the hopper of the paving machine. In other strategies, a machine known generally in the art as a material transfer vehicle will pick up loads of paving material deposited at a work site and shuttle the paving material to one or more paving machines, more or less on an as-needed basis.

It is generally desirable to avoid interruptions in paving material supply, but also generally desirable to avoid oversupplying paving material. In other words, to operate a paving system as efficiently as possible it is generally desirable to control the rate of supplying/resupplying paving material to a paving machine to avoid situations where paving progress stops because the machine runs out of material, and also to avoid situations where excess material is supplied. If excess material is supplied, then the storage capacity of the paving machine hopper may be exceeded. It may then be necessary to manually shovel excess material out of the paving machine hopper or remove material from a windrow to avoid overwhelming the paving machine and causing system down time. Likewise, it is typically desirable to avoid idling the paving machine by inadvertently halting material supply.

For the reasons explained above, it will be readily apparent that providing a consistent and accurate supply of paving material to a paving machine can be critical if paving is to progress at a theoretical optimum efficiency. In many instances, a paving machine operator or other personnel will be responsible for ordering the resupply of paving material to the paving machine. Paving material may be ordered based on visual observation of the material supply available, experience and, to a large extent, guesswork. In one conventional system, workers on the ground manually control depositing of paving material onto a work surface ahead of the paving machine. One problem with manual control strategies is that the personnel responsible for controlling a location and/or quantity of paving material deposited onto the work surface may not be capable of controlling the discharge amount or location of paving material with sufficient precision as to time, location or quantity to avoid oversupply or undersupply. Moreover, personnel responsible for controlling delivery and deposition of paving material on the work surface may not be privy to the actual volume of material needed, much less aberrations or changes in the rate of paving of the paving machine or the amount of material the paving machine is putting down. For example, during operation a paving machine may change paving width and paving thickness regularly. While an observer may make basic assumptions as to the rate at which paving material is being placed by the paving machine or a quantity of material required to pave a particular stretch of road, for instance, visual observation and experience are often insufficient to accurately determine how much material should be laid down ahead of a paving machine for pick-up. These and other confounding factors tend to compromise the efforts of even skilled site managers and machine operators to run a paving system at optimum efficiency.

United States Patent Application No. 2006/0002762 to Crampton is directed to a method and apparatus for spreading aggregate and road building materials onto a surface in relation to speed of a spreading machine. Crampton teaches a spreader assembly for controlled delivery of aggregate materials from a hopper to a surface. Crampton recognizes that some aspects of road quality can relate to depositing a measured and/or uniform amount of material. However, while Crampton may be suited to a certain type of machine system or paving strategy, Crampton is not concerned with nor applicable to supplying material for subsequent placement with a paving machine. Moreover, Crampton does not recognize the need or advantages to communicating certain types of data among machines of a complex system.

SUMMARY

In one aspect, a method of operating a machine system includes a step of receiving expected material placement data for a paving machine, the paving machine being adapted to receive material from a first supply volume external to the paving machine, transfer the material through a second supply volume internal to the paving machine and to place the material on a work surface via a material placing mechanism of the paving machine. The method further includes the steps of receiving actual material placement data for the paving machine, and outputting a signal based on a comparison between the expected material placement data and the actual material placement data. The method still further includes a step of commanding replenishing material from a supply machine to the second supply volume responsive to the signal.

In another aspect, a machine system includes a paving machine having a frame, a plurality of ground engaging elements, a hopper, a conveying mechanism and a material placing mechanism. The material placing mechanism is adapted to receive a material from the hopper via the conveying mechanism for placing the material on a work surface. The paving machine further includes an internal material supply volume for the machine system defined in part by the hopper and in part by the conveying mechanism. The machine system further includes a control system having a computer readable memory configured to store expected material placement data for the paving machine, and a receiver configured to receive actual material placement data for the paving machine. The control system further includes a data processor coupled with a computer readable memory and with the receiver. The data processor is configured to compare the expected material placement data with the actual material placement data, and further configured to output a supply machine control signal to control replenishing material via a supply machine to an external material supply volume for the paving system in a manner responsive to comparing the expected material placement data with the actual material placement data.

In still another aspect, a paving control system for a paving system includes a computer readable memory configured to store expected material placement data indicative of expected material placement by a paving machine, and a receiver configured to receive actual material placement data for the paving machine. The paving control system further includes a data processor coupled with the computer readable memory and with the receiver, the data processor being configured to compare the expected material placement data with the actual material placement data. The data processor is further configured to output a control signal to a supply machine to controllably replenish material to an external material supply volume for the paving system in a manner responsive to comparing the expected material placement data with the actual material placement data.

DETAILED DESCRIPTION

Referring toFIG. 1, there is shown a paving system10according to one embodiment. Paving system10is shown as it might appear at one stage of paving a work surface “S” with a mat of paving material “Z” via a paving machine12. Paving machine12is illustrated loading material from a windrow W1during paving. A first section of surface S has been paved with mat Z as shown, and a subsequent section is yet to be paved. Also shown inFIG. 1are a plurality of supply machines of machine system10, including a first supply machine60aand a second supply machine60b. Each of supply machines60aand60bmay include a frame62a,62b, and a set of ground engaging elements64a,64b, mounted to frame62a,62b. Each of supply machines60aand60bmay further include a material storage container66a,66bfor storing and transporting a material such as a paving material about a work site for supplying to one or more paving machines of paving system10. Supply machine60ais shown storing an on-board material load M1whereas supply machine60bstores a relatively smaller on-board material load M2. In one embodiment, supply machines60aand60bmay be used to periodically supply a paving material to work surface S for pick-up via paving machine12, and eventual use in paving mat Z. Supply machines60aand60bmay also periodically travel to an asphalt plant to obtain additional paving material as needed. InFIG. 1, a first windrow start location P1and a second windrow start location P2are shown. In one embodiment, start location P1represents a preliminarily planned windrow start location corresponding to a preliminary material supply/delivery plan for machine system10. Start location P2represents a different, or updated, start location which may be selected if the initially planned start location P1is determined to be inappropriate. The significance of start locations P1and P2will be further apparent from the following description. Rather than depositing material in a windrow for pick-up by paving machine10, in certain embodiments the teachings set forth herein may also be applied to strategies using one or more material transfer vehicles to supply paving machine12, and such other paving machines as might be a part of machine system10. As further described herein, by gathering certain data and communicating among the various machines of machine system10, paving machine12will be capable of paving mat Z while reducing any risk of halting operation due to interrupted or excessive material supply.

Paving machine12may further include a frame13which includes a hopper22configured to store paving material for supplying to a material placing mechanism18such as a screed assembly of paving machine12. Paving machine12may further be configured to pick up paving material from windrow W1via a windrow elevator24. Supply machines60aand60bmay each be configured to place material on work surface S in a controlled fashion to replenish windrow W1and/or start a new windrow. In one embodiment, windrow elevator24may be coupled with frame13and may extend forwardly thereof to allow paving material to be elevated from windrow W1into hopper22in a conventional manner. Windrow elevator24might include augers, conveyors or the like (not shown) for this purpose. As mentioned above, rather than using a windrow elevator24, a separate machine such as a material transfer vehicle might be used for supplying paving material from a storage location to paving machine12. In many instances, paving system10may be used for paving surface S via an asphalt material including a mixture of aggregates and petroleum products, well known in the art. In other embodiments, rather than an asphalt material, “paving” material as described herein might be an aggregate material, a concrete material for subsequent roller compaction, or still another material. It should thus be appreciated that the present disclosure is not strictly limited to paving or placing a material of any particular composition. In any event, windrow W1may include a first supply volume or “external” supply volume14and paving machine12may be configured to receive material from the first supply volume14, transfer material through a second supply volume internal to paving machine12and place the material on work surface S via material placing mechanism18.

Paving machine12may further include a plurality of ground engaging elements26such as ground engaging tracks, wheels or the like, for propelling paving machine12along work surface S. In one embodiment, material placing mechanism18may include a screed as mentioned above. Material placing mechanism18may further include a width adjustable screed having a set of screed width actuators54, and may also include a set of screed height actuators50. Paving machine12may further include a control system32whereby paving machine12monitors a variety of operating parameters of paving system10, and controls various operations of paving machine12and supply machines60aand60b, as further described herein.

Referring also toFIG. 2, there are shown additional features of paving system10and paving machine12, with paving machine12shown having progressed slightly ahead of the position depicted inFIG. 1. Supply machine60ahas been dispatched to replenish supply volume14, such as by starting a new windrow W2at windrow start location P2instead of P1, for reasons further explained herein. Paving machine12may further include a conveyor20as shown inFIG. 2adapted to convey paving material from hopper22to material placing mechanism18in a conventional manner. Hopper22and conveyor20may define at least in part a second supply volume16or “internal” supply volume, as mentioned above. Thus, supply volume14and supply volume16may together include a total amount of material presently available for use by paving machine12.

Returning toFIG. 1, it may be noted that paving machine12may be picking up and loading material continuously into hopper22so long as paving machine12is interacting with a windrow. If a paving machine is receiving material from an external supply volume such as a windrow faster than the paving machine is placing material on a surface, then material in the machine's internal supply volume will increase in quantity. Similarly, if a paving machine is placing material faster than it is receiving material, then the material in the machine's internal supply volume will decrease in quantity. If the subject paving machine continues to operate with a supply/placement disparity, then eventually its hopper will either overflow or become empty. In either case, operation is halted to remedy the situation. Paving machines are typically equipped with a sufficiently large internal supply volume that the machine can tolerate a supply/placement disparity for some time. If operation with a supply/placement disparity continues, however, the paving machine will eventually have to stop operating. By way of the automated material supply and material placement feedback mechanisms further described herein, the present disclosure may be understood as enhancing the ability of a paving machine, and an overall paving system, to accommodate supply/placement disparities. A total material supply volume presently available for use by paving machine12, including external supply volume14and internal supply volume16, will tend to be matched relatively more closely to an actual need for material than in conventional systems. Accordingly, when supply/placement disparity does occur, a paving machine such as paving machine12will tend to be more likely to have available internal supply volume to accommodate surges in material supply, surges in material placement, or reductions in material supply or material placement.

InFIG. 1, a subsection of surface S, identified via reference letter “T”, includes an enlarged width relative to other subsections of surface S. It may be expected that paving machine10will place a relatively greater amount of material in subsection T than on other sections of surface S. To accommodate an increase in material demand by paving machine10to pave the relatively wide subsection T, a portion of windrow W1is slightly enlarged beginning prior to subsection T. In a real world example, windrow W1may or may not be enlarged as shown, however, as will be further apparent from the following description, tailoring windrow height and/or width based on expected material demand and actual material usage by paving machine12is contemplated to be one practical implementation of the present disclosure. In certain instances, a windrow might change regularly in cross sectional area to accommodate expected changes in paving material demand from paving machine10. It should be appreciated, however, that the improved efficiency goals of the present disclosure may be realized without tailoring windrow size or shape, such as by controlling windrow start locations and windrow stop locations, and thusFIG. 1is purely illustrative. In the present context, windrow size or shape may be understood as a mass quantity profile of a windrow. In any event, however, it will be appreciated for reasons further described herein that machine system10and paving machine12are uniquely configured as compared to state of the art systems to efficiently and automatically control placement of material for supplying paving machine10based on expected material demand and actual material usage. This contrasts with earlier systems where experience and visual observation provided essentially the sole means for controlling material placement in a paving system.

Control system32may further include an electronic control unit40configured by way of software and/or hardware control to implement an operating method for machine system10according to the present disclosure. Electronic control unit40may be resident on paving machine12in one embodiment, and may include a host computer for monitoring and controlling machine system10. In another embodiment, a host computer of machine system10/control system32could be positioned on another of the machines of machine system10, or at a site management office or the like. Electronic control unit32may include a computer readable memory44such as RAM, ROM, flash memory or another suitable type of memory and a data processor42in communication with computer readable memory44. Control system32may further include a display38viewable by an operator at an operator station28and being configured to display information for controlling and/or monitoring machine system10to an operator, as further described herein. Operator station28may be one of two operator stations for paving machine12, however, only a single operator station is illustrated and described herein.

Electronic control unit40may be in communication with a set of screed control sensors of control system32, including for example screed height sensors52which are coupled with screed height actuators50. Control system32may further include additional screed control sensors such as a set of screed width sensors56coupled with screed width actuators54and in communication with electronic control unit40. Screed height sensors52and screed width sensors56may be part of a sensing system46for communicating actual material placement data to electronic control unit40. In one embodiment, sensing system46may output sensor signals to electronic control unit40which are indicative of a width and thickness of mat Z. Sensing system46might also include a speed sensor (not shown) monitoring a speed of conveyor20, a ground speed sensor (not shown) monitoring a ground speed of paving machine12or a weight sensor (not shown) monitoring a weight of material in hopper22. A history of sensor signals from sensing system46may be used to determine or estimate a quantity of material placed by paving machine12during paving mat Z and/or to determine or estimate a rate at which material is being placed by paving machine12. For example, if screed assembly18is positioned at height “X” and width “Y” for “N” seconds at a ground speed of “G” meters per second, a total quantity of material placed by paving machine12in a given length of time or a rate of placing material with paving machine12can be estimated. Monitoring some or all of the other listed parameters such as conveyor speed or material weight could also be used to calculate or further refine estimates or determinations of material placement quantity or material placement rate with paving machine12.

Control system32may further include a transmitter34configured to output control signals to other machines of paving system10such as supply machines60aand60b. Control system32may also include a receiver36configured to receive data such as paving machine position data indicative of a position of paving machine12relative to a reference position. Global or local positioning may be used. Receiver36may also be configured to receive data from other machines of paving system10such as supply machines60aand60b, as further described herein. Where electronic control unit40is resident on paving machine12, electronic control unit40may itself be considered a receiver configured to receive material placement data as described herein from sensing system46.

Each of supply machines60aand60bmay further include a sensing system68a,68bresident thereon, which is adapted to monitor various operating parameters of supply machines60aand60bsuch as on-board material quantity stored in material storage containers66a,66bvia a sensor71a,71bsuch as a weight sensor. Sensing systems68aand68bmay also each include another sensor69a,69badapted to sense a parameter indicative of a material discharge quantity when material is placed via the corresponding machine to replenish windrow W1. Each of supply machines60aand60bmay further include a control system70aand70b, respectively, which is resident thereon and configured to communicate as further described herein with control system32of paving machine12. Each control system70aand70bmay include an electronic control unit72a,72bwhich is in communication with a receiver76a,76band a transmitter74a,74b. Each sensing system68aand68bmay be adapted to communicate with the corresponding electronic control unit72aor72b, which may output signals via transmitters74aand74b, respectively, to control system32of paving machine12. In one embodiment, the outputted signals may include sensor signals which are indicative of a material quantity stored within the corresponding storage containers66aand66b. The outputted signals may also include material discharge data based on sensor input from sensing systems68aand68bwhich are indicative of a quantity of material discharged by the corresponding supply machine60a,60b, as described herein. Each of supply machines60aand60bmay also include a receiver76aand76b, respectively, adapted to receive supply machine control signals output via transmitter34of paving machine12. Receivers76aand76bmay also be configured to receive position signals indicative of a position of the corresponding supply machine60aand60b.

Each of supply machines60aand60bmay further be configured to replenish windrow W1, or deposit an additional windrow, via controllably discharging paving material from the corresponding storage container66aand66bonto work surface S. To this end, each of supply machines60aand60bmay be equipped with a material discharge control mechanism78a,78bwhich is configured to control opening, closing and position of a control gate80aand80b. Each discharge control mechanism78aand78bmay further include a gate actuator82a,82bcoupled with the corresponding gate80aand80b. A gate control sensor69aand69bmay be coupled with a corresponding gate actuator82aand82band configured to output sensor signals indicative of a position of the corresponding gate actuator82aand82b. The sensor signals output via gate control sensors69a,69bmay include material discharge quantity data as mentioned above, since a position history of gate80aand80bduring a material discharge cycle may be indicative of a material discharge quantity discharged via supply machines60aand60bwhen replenishing supply volume14. Sensor data from sensors71band71amight also comprise the material discharge data.

As discussed above, electronic control unit40may serve as a host computer for monitoring and controlling activities of machine system10. To this end, computer readable memory44may store a material supply control algorithm which includes computer executable code thereon. Electronic control unit40may be configured via data processor42to execute the material supply control algorithm to control placing material in a windrow on work surface S with one or both of supply machines60aand60bfor pick-up by or delivery to paving machine12. The material supply control algorithm may include an actual material placement term corresponding to actual material placement data received from sensing system46as described herein. The material supply control algorithm may further include a material discharge term corresponding to material discharge quantity data received from sensing systems68aand68bas described herein. The material supply control algorithm may further include a paving machine position term and a supply machine position term, corresponding to paving machine position data and supply machine position data as described herein. Electronic control unit40may be configured via data processor42to output a supply machine control signal responsive to a position of paving machine12, responsive to a position of supply machine(s)60a,60b, and responsive to comparing the actual material placement data with expected material placement data for paving machine12, as further described herein. Execution of the subject control algorithm will be further understood by way of the description of an example control process executed via electronic control unit40as set forth below.

INDUSTRIAL APPLICABILITY

Referring toFIGS. 3a-d, there is shown a flowchart100illustrating an example control process according to the present disclosure. The process of flowchart100may start at step102. From step102, the process may proceed to step104to receive site data. The site data may include data specific to a particular work site, including but not limited to an area to be paved, an average lift thickness of material to be used during paving, an approximate distance expected to exist between different paving machines operating at the work site, a distance between a work site and an asphalt plant, if applicable, etc. The site data may also include data specific to the particular paving system being used, such as a number of paving machines which will be working, machine travel/paving speeds, a number of supply machines which are available for replenishing material to the paving machines, etc. From step104, the process may proceed to step106to receive expected material placement data. In one embodiment, receiving expected material placement data may include receiving electronic data indicative of at least one of an expected material placement rate or an expected material placement quantity associated with each paving machine of machine system10. For example, the electronic data may include data indicative of an expected “X” cubic meters of paving material placed per hour, or an expected material placement quantity of “Y” total kilograms of paving material, etc. Expected material placement data will thus typically be based on mechanical attributes of a paving system such as theoretical maximum or minimum paving speeds of one or more paving machines of paving system10, and may also be based on attributes of the specific work site such as length and width of a surface to be paved, mat or lift thickness, material type, surface grade, ambient temperature, and a host of other factors known by those skilled in the art to affect a quantity of material placed by a paving machine or a rate of material placement. It should further be appreciated that the expected material placement data may be unique to paving machines of a particular configuration or paving machines operating under particular circumstances.

For instance, a paving machine placing paving material on a curving roadbed or a slope might be expected to operate at a different material placement rate than a paving machine paving a straight, level surface. Similarly, a paving machine paving a mat of a particularly wide width may place material at a different rate or at a different total quantity than a paving machine paving material in a mat of a relatively narrower width. Further still, the internal mechanisms of a paving machine such as the feed rate of conveyer20in paving machine12may affect the expected material placement data. It should thus be appreciated that expected material placement data may include a variety of material placement parameters, and may vary among paving systems. The expected material placement data may further include a calculated material placement amount and/or rate which is estimated or determined on-board paving machine12by electronic control unit40responsive to the site data. Known techniques such as mapping work surface S with a machine mounted system may be used to gather the site data which, in conjunction with data specific to the machines of paving system10as described herein, may be used to determine expected material placement quantity, rate, etc.

From step106, the process may proceed to step108to plan material delivery times, material delivery quantities and material delivery locations based on the site data and expected material placement data. Step108may further be understood as establishing a material delivery/supply plan for replenishing first supply volume14based in part on the expected material placement data. Establishing a material delivery/supply plan may also include planning material delivery times, etc. for delivering material to additional paving machines of machine system12. In one embodiment, at or prior to step108, expected position data indicative of an expected position of one or more paving machines of paving system10and an expected position of supply machines60aand60bat certain times during paving surface S may be received. Expected positions may be based on an expected progress rate, such as expected average travel speed of paving machine12. Establishing the material delivery/supply plan may further include establishing the material delivery plan based also in part on the expected position data. It may thus be appreciated that, at step108, a variety of different plan parameters may be selected, and a plan established for which machines should be positioned at, or traveling to, what locations, at certain times, to deliver certain quantities of material. The material delivery plan may thus include one or more time terms, position terms, and material quantity terms. As will be further apparent from the following description, establishing the material delivery plan may be understood as establishing a preliminary material delivery/supply plan which is expected to be updated as paving progresses at the work site.

From step108, the process may proceed to step112to commence paving. From step112, the process may proceed to step114to track paving machine locations or positions. As explained above, in some systems multiple paving machines may be used, whereas in other systems such as paving system10a single paving machine may be used. From step114, the process may proceed to step116to track material usage by paving machine12of paving system10. In one embodiment, tracking material usage may include tracking a quantity of material which is used by paving machine12, such as a total amount of material which has been placed thereby. In other instances, tracking material usage in step116might include tracking a rate of material usage by paving machine12, and such other paving machines as may be used in paving system10. Tracking material usage may be further understood as receiving actual material placement data for paving machine12. In some instances, the actual material placement data may include electronic data indicative of a non-uniform actual material placement rate, such as might be expected in paving surface S, where paving width changes for subsection T.

From step116, the process may proceed to step118to query whether any windrow needs replenishing soon. It is assumed at this point that a windrow such as windrow W1has been previously provided prior to commencing paving. At step118, electronic control unit40may be understood as determining, based on the previously established material delivery plan, whether any paving machine of machine system10is expected to approach a predefined pick-up location or windrow start location within a predefined period of time.FIG. 1illustrates a first pick-up location P1, which was previously determined in step108. At step118electronic control unit40may be understood as determining whether actions need to be initiated to replenish paving material to paving machine12, or another paving machine. If no, the process may proceed to step122to alert a host computer, or the process could loop back to an earlier point in the control routine. If, at step118, a windrow is determined to need replenishing soon, the process may proceed to step120.

At step120, electronic control unit40may query whether supply machines such as supply machines60aand60bcan be located. If no, the process may proceed to step122to alert the host computer. If yes, the process may proceed to step124to compare the supply machine locations with planned delivery locations. From step124, the process may proceed to step126to receive material quantity data from a first supply machine such as supply machine60a. From step126, the process may proceed to step128to receive material quantity data from a second supply machine such as supply machine60b. Supply machine60amight output signals indicating it has a full material load M1, whereas supply machine60bmight output signals indicating it has only a partial material load M2. From step128, the process may proceed to step130to compare the material quantity data from supply machines60aand60bwith the plan data. In other words, at step130electronic control unit40may be determining a difference between a material quantity which is expected to be needed at a predefined location such as P1, and at a predefined time, for replenishing supply volume14, with a material quantity stored by each of supply machines60aand60b. From step130, the process may proceed to step132.

At step132, electronic control unit40may query whether there is a supply machine with sufficient material. If no, the process may proceed to step136to alert the host computer. If yes, the process may proceed to step134to query whether there is a supply machine which can arrive on time. If no, the process may proceed from step134to step136to alert the host computer. If there is a supply machine which can arrive on time at step134, the process may proceed to step138to select a supply machine. Selecting a supply machine, such as selecting one of supply machines60aand60bmay include selecting a supply machine based on the material quantity contained within the corresponding storage container62aor62b, and may also take place based on the relative proximity of the available supply machines to paving machine12. In some instances, it might be desirable to deliver material from one of supply machines60aand60b, even if the quantity of material is less than the quantity of material called for by the material delivery plan, if the respective supply machine is in close proximity to paving machine12. Similarly, a supply machine which contains an excess quantity of material, more than what is called for by the material delivery plan, might be selected if it is determined that the material supply machine could drop the excess material at a second delivery location in close proximity to the delivery location for paving machine12.

From step138, the process may proceed to step140to query whether the selected supply machine needs to deliver at its current location. In other words, at step140electronic control unit40may be determining whether a supply machine might be in the process of or about to deliver material at its current location, and thus might not be available for replenishing material to paving machine12. If, at step140, the selected supply machine needs to deliver at its current location, the process may proceed to step142to flag the selected supply machine as unavailable, and may thenceforth return to execute steps132-140again. If the selected supply machine does not need to deliver at its current location at step140, the process may proceed to step144to output a dispatching signal to the selected supply machine. The selected supply machine may travel to the planned supply location responsive to the dispatching signal. From step144, the process may proceed to step146to query whether the windrow needs replenishing now. If no, the process may proceed to step148to idle the selected supply machine and alert the host computer. If at step146the windrow needs replenishing now, the process may proceed to step150to receive actual material placement data.

In step150, electronic control unit40may be understood as receiving actual material placement data corresponding to an actual quantity of material placed by paving machine12or an actual material placement rate of paving machine12, as described herein. From step150, the process may proceed to step152where data processor42compares the expected material placement data with the actual material placement data. From step152, the process may proceed to step154to output a signal responsive to comparing expected material placement data with the actual material placement data. In one embodiment, the signal may correspond to a difference between the expected material placement data and the actual material placement data, such as an arithmetic difference between an expected material placement quantity and an actual material placement quantity. From step154, the process may proceed to step156to query whether the planned delivery amount will overfill the hopper. If yes, the process may proceed to step160to output a plan updating signal. If no, the process may proceed to step158to query whether the planned delivery will underfill the hopper. If yes, the process may proceed to step160. If no, the process may proceed to step162. If planned material delivery of a given quantity will overfill or underfill hopper22, electronic control unit40may output a plan updating signal at step160. Outputting the plan updating signal may update the previously determined material supply control algorithm. Updating the material delivery/supply plan may include updating an originally planned delivery location and/or an originally planned delivery quantity. Updating the material delivery/supply plan may further include updating a material quantity term, a machine position term, or a material delivery time term of the material delivery/supply plan. Each of these potential actions may be understood as inhibiting overfilling or underfilling hopper22, as the case may be, since changing material delivery quantity, material delivery location or material delivery time can be used to control an amount of material which will exist in external supply volume14at any one time.

From either of step158or step160, the process may proceed to step162to output control commands from the host computer such as electronic control unit40to the selected supply machine such as supply machine60abased on the current material delivery/supply plan. Thus, at step162, electronic control unit40is calculating control commands based on the current material delivery/supply plan, whether it be the updated plan or the original, preliminary plan as discussed above. The outputted control commands may include supply machine control signals. From step162, the process may proceed to step164to actuate the material discharge mechanism of the selected supply machine responsive to the control commands. The selected supply machine, and/or control system32may be tracking supply machine location, and hence controlling material discharge responsive also to supply machine position signals. From step164, the process may proceed to step166to receive sensor feedback from the material discharge mechanism indicative of material discharge quantity. From step166, the process may proceed to step168to query whether the sensor feedback validates that the correct amount of material was delivered. If no, the process may proceed to step170to alert the host computer. From step170, the process may proceed to step172to query whether there is a need for manual intervention. If yes, the process may proceed from step172to step174to display an alert to the paving machine operator via display38, for example. If no, the process may proceed ahead to step178. If, at step168, the sensor feedback validates that the correct amount was delivered, the process may proceed to step176to output a plan validation signal. From step176, the process may proceed to step178to display an anticipated next delivery location to the supply machine operator. From step178, the process may proceed to step180to End.

Referring toFIG. 4, there is shown display38of control system32, in an example display state. Display38may include a display screen39which is configured to display graphs, illustrations, alerts, etc., to an operator of paving machine12, or to other personnel, for monitoring activities of machine system10in real time. In the example display state shown, paving machine12is shown approximately in the same relative location on surface S as that depicted inFIG. 2. It should be appreciated that the illustration of display38inFIG. 4represents one practical example of how certain data acquired and processed during executing the control algorithm described above may be communicated to an operator. Thus, while the flowchart ofFIGS. 3a-drepresents by way of example certain of the automated functions which take place during operating machine system10,FIG. 4represents incorporation of monitoring and control by a human operator. It should be appreciated, however, that in certain embodiments, the automated actions of machine system10may take place in a manner transparent to an operator, whereas in other instances such as that presently described, at least certain proposed automated actions may be considered and confirmed or rejected by an operator.

Display38may also include a power button45, a speaker43, and a keypad41or the like. In one embodiment, display38may display information to an operator of paving machine12such as expected material placement amount via a curve “E”, an actual material placement amount via a curve “A” and an approximate paving machine position “M” relative to a start location “Q” on surface S. Based on a difference between curves E and A, display38may thus provide to an operator an approximation of a difference between an expected material placement amount or material placement rate and an actual material placement amount or material placement rate. Display38may also indicate to an operator a proximity of machine12to certain features of surface S, such as the enlarged width subsection T. Accordingly, an operator is provided a display representation of paving machine location, expected material placement quantity or rate, actual material placement quantity or rate and indications of upcoming expected changes in material placement. Display38may be coupled with electronic control unit40, and thus its display state may be continually updated.

By viewing display38as shown inFIG. 4, an operator may readily understand that paving machine12is placing less material than expected, given the difference between curves E and A. The operator will also understand that an increase in paving material supply is expected, corresponding to the increase in the mass quantity profile of windrow W1prior to enlarged subsection T of surface S. Display38may also convey to an operator an approximate proximity to a planned windrow start location P1. It will be recalled that windrow start location P1represents an initially planned windrow start location where a supply machine is to start a windrow on surface S for replenishing material to external supply volume14. Given that paving machine12is placing less material than expected, and an increase in the material supply is expected soon, an operator and/or electronic control unit40might conclude based on the display state of display38inFIG. 4, that a possibility of overfilling hopper22exists if replenishing external material supply volume14proceeds as originally planned. Specific alert signals might be communicated to display38from electronic control unit40, such as audible alerts to speaker43or visual alerts on display screen39.

It will be recalled that electronic control unit40may determine based on comparing expected material placement data with actual material placement data whether a likelihood of overfilling or underfilling hopper22exists. If, in the scenario depicted inFIG. 4, overfilling hopper22is likely to occur, electronic control unit40may decide to update the material delivery plan such that material delivery takes place at a different location than a previously planned location. It will further be recalled that execution of a material delivery/supply control algorithm as discussed above contemplates establishing a preliminary material delivery plan. In the present scenario, the original delivery location or windrow start location was planned to be at point P1. Since it appears that overfilling hopper22is likely if delivery takes place as originally planned, electronic control unit40may output a plan updating signal, updating the material delivery plan based on operation of machine system10in real time. In one embodiment, the plan updating signal may change the originally planned delivery location to a new location, corresponding to location P2as shown on display screen39. An icon such as an arrow “V” on display screen39or some other operator perceptible alert may be used to notify the operator that a new windrow start location has been selected. In one embodiment, operator confirmation of the selection of the new windrow start location may take place via inputting a confirmation command via keypad41.

Once confirmation of the updated plan and updated windrow start location is received from the operator, electronic control unit40may initiate the steps necessary to control discharging material onto surface S with a supply machine to replenish external supply volume14according to the updated plan.FIG. 2illustrates supply machine60adelivering material at the updated windrow start location P2. If underfilling hopper22were determined to be likely, the updated material delivery location might be relatively closer to paving machine12. It will further be recalled that in addition to or instead of updating material delivery locations, the material delivery quantity may be updated based on real time data. Thus, in the scenario described in connection withFIG. 4, an operator might also confirm an updated material quantity term. Other aspects of operating machine system10could also integrate monitoring and control by a human operator, such as validating a material delivery plan. For example, an operator could be provided various data via display38such as yet another curve indicating a quantity of material discharged via supply machine60a. The operator could, based on the display data, confirm that planned material delivery quantities, times, locations, etc., were reasonably close to what was actually needed, confirm that no manual intervention was required, etc. In each of these cases, confirmation or rejection of plan parameters could be used to tailor the material delivery algorithm for use in subsequent control of machine system10.

The present description is for illustrative purposes only, and should not be construed to narrow the breadth of the present disclosure in any way. Thus, those skilled in the art will appreciate that various modifications might be made to the presently disclosed embodiments without departing from the full and fair scope and spirit of the present disclosure. Other aspects, features and advantages will be apparent upon an examination of the attached drawings and appended claims.