Patent Publication Number: US-8116950-B2

Title: Machine system and operating method for compacting a work area

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to systems and strategies for compaction of material, and relates more particularly to assigning different compaction targets to different regions of a work area based on a varying compaction response of material therein. 
     BACKGROUND 
     Many construction, road building and other activities utilize compactor machines to compact material such as soil, asphalt, etc. and increase the density of the material for load bearing purposes. Compaction is also used for reducing material volume, as in the case of landfill trash. Conventional wisdom is to pass a compactor uniformly across a work area until the work material has been increased in density to a sufficient degree. While a uniform coverage approach is simple and straightforward, it has certain drawbacks. 
     Material within different regions of a work area will often tend to compact non-uniformly. In other words, for a given number of passes with a compactor there may be variation in the relative increase in density of the material among different regions of a work area. As a result, where uniform coverage is used certain areas may be under-compacted, certain areas may be over-compacted or the project may require an excessive amount of time. Expenses associated with operating construction machinery such as compactors can therefore often be high due to wasted effort by the compactor machine and necessary remediation where compaction does not occur as intended. In recent years, a variety of strategies have been proposed for improving compactor efficiency, such as systems which measure the density of compacted material and other strategies where the response of material to compaction in real time is monitored. While certain of these techniques have shown promise, there remains room for improvement. 
     It is common at construction sites for compaction specifications to be provided to a construction manager or contractor. In particular, a relative compaction state or minimum compaction value, minimum number of compactor passes, and other factors may be specified. There may be a number of different ways in which a work area can be compacted to satisfy the compaction specifications. For example, the entire work area might be compacted to within 90% of a specified minimum compaction value. Alternatively, a portion of the work area could be compacted to 100% of the specified minimum compaction value, whereas another portion might be compacted to a lesser degree of compaction. Still other combinations of compaction minimum value, compactor coverage, etc., can be imagined, and to a certain extent the manner in which specifications are met may be based on agreements between the contractor and the client. Department of Transportation agencies also commonly specify certain compaction state and/or compactor coverage requirements. 
     As mentioned above, improved sensing and control strategies have been proposed for operating compaction machinery in recent years, but still exhibit certain shortcomings. One problem in particular is that known systems often do not take into account the possibility of meeting compaction specifications by selecting one of multiple possible ways in which a machine system can be operated or navigated to compact a work area. In other words, while known systems might allow compaction of a work area to satisfy specifications more efficiently than relying simply on uniform coverage or operator judgment, these known strategies do not actually provide for calculation or estimation of the most efficient way to do so. Commonly owned U.S. patent application Ser. No. 11/517,065 to Congdon et al, filed Sep. 7, 2006, for example, discloses a concept where aberrant compaction response of a material is detected. The strategy of Congdon et al. promises significant efficiency improvements, as fruitless work on aberrantly responding material is avoided, but is not specifically directed to compacting non-aberrant material in an efficient manner. 
     The present disclosure is directed to one or more of the problems or shortcomings set forth above. 
     SUMMARY 
     In one aspect, a method of operating a machine system for compacting a work area includes a step of receiving electronic data indicative of a varying compaction response of material within a work area, and a step of linking the electronic data with location data for the work area. The method further includes a step of assigning each one of at least two different compaction targets to a different region of the work area, in response to linking the electronic data with location data. 
     In another aspect, a machine system includes a compactor having a frame and at least one compacting element coupled with the frame, and a sensing system configured to output signals including electronic data indicative of a varying response of material within a work area to interaction of the compactor therewith. The machine system further includes an electronic control unit coupled with the sensing system and configured to link the electronic data with location data for the work area, the electronic control unit being further configured to assign each one of at least two different compaction targets to different regions of the work area responsive to linking the electronic data with the location data. 
     In still another aspect, a machine control system includes an electronic control unit configured to receive signals including electronic data indicative of a varying response of material within a work area to interaction of a compactor therewith, the electronic control unit being further configured to receive location data for the work area and to link the electronic data with the location data and responsively assign each one of at least two different compaction targets to different regions of the work area. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side diagrammatic view of a machine system according to one embodiment; 
         FIG. 2  is a hypothetical data display scenario using a display of the machine system of  FIG. 1 ; 
         FIG. 3  is another hypothetical data display scenario using a display of the machine system of  FIG. 1 ; 
         FIG. 4  is another hypothetical data display scenario using a display of the machine system shown in  FIG. 1 ; 
         FIG. 5  is yet another hypothetical data display scenario utilizing the display of the machine system shown in  FIG. 1 ; and 
         FIG. 6  is a flowchart illustrating an example control process according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , there is shown a machine system  8  for use in compacting a work area. Machine system  8  may include a compactor  10  having a frame with a front frame unit  13  and a back frame unit  12 . Compactor  10  may further include an operator cab  18  having therein an operator input device such as a steering wheel  20  or similar control device for controlling a travel direction of compactor  10 . A position or location signal receiver  24  may be mounted on one of frame units  12  and  13 , and configured to receive position signals from a signal transmitter such as a global positioning satellite(s), or another system such as a ground based laser positioning system. Compactor  10  may further include a control system  28  configured to control various aspects of compactor operation, further described herein. Compactor  10  may also include a sensing system  22  having at least one sensor  26  configured to output sensor data signals or “sensor data” indicative of a compaction response of a material with which compactor  10  is interacting, also further described herein. Control system  28  may further include an electronic control unit  30  which receives data inputs from sensing system  22  and utilizes the data inputs to plan or control compactor navigation within a work area to enable operation of machine system  8  in an efficient manner, as will be further apparent from the following description. 
     Sensing system  22  may be in communication with electronic control unit  30  via a communication line  31 . Receiver  24  may communicate with electronic control unit  30  via another communication line  33 . A display  50  including an input device  52  mounted thereon or integral therewith, or positioned separately from display  50 , may be located at operator cab  18  and coupled with electronic control unit  30  via yet another communication line  53 . In one embodiment, compactor  10  may include a steering system  44  having at least one actuator  46  such as a hydraulic actuator controlled via a control valve  48 , and configured to adjust an articulation angle between front frame unit  13  and back frame unit  12  at an articulation joint  42 . Compactor  10  is shown in the context of a double drum compactor having a front compacting drum  16  mounted to front frame unit  13 , and a back compacting drum  14  mounted to back frame unit  12 , however, it should be appreciated that other embodiments are contemplated wherein compactor  10  includes only one compacting drum, such as a front compacting drum and includes tires in place of a back compacting drum. In still other embodiments, rather than conventional compacting drums, pad foot or sheep&#39;s foot style compacting elements might be used, such as for a landfill trash compactor. Multiple front drums and/or multiple back drums may also be used. Steering/travel direction of compactor  10  may be controlled via an operator manipulating steering wheel  20 . In other embodiments, compactor  10  might be an autonomous machine where electronic control unit  30  is configured via software and/or hardware control to operate steering system  44  via computer generated control signals. Another communication line  45  connects electronic control unit  30  with control valve  48 , or an actuator thereof. Other manual or automated features such as a vibratory apparatus (not shown) might be associated with one or both of front and back drums  16  and  14 . It should further be appreciated that, while communications between and among components of compactor  10  are described as utilizing communication “lines,” wireless communication might be used. Further, compactor  10  could communicate wirelessly with a control station or the like, and control system  28  might be positioned remotely in some embodiments. 
     As mentioned above, sensor  26  may be configured to sense values indicative of a compaction response of material with which compactor  10  interacts. In other words, sensor  26  may be configured to monitor a parameter during operating compactor  10  which is indicative of a change or lack of change in relative compaction of a material such as soil, gravel, concrete, asphalt, landfill trash and mixtures thereof, etc., as compactor  10  is moved over the material within a work area. Sensor  26  may be a single sensor, or a set of sensors, configured to sense a relative rolling resistance of compactor  10  as it moves within a work area. Rolling resistance sensed via sensor  26  may indicate relative compaction of material across which compactor  10  is moved. A change in rolling resistance from one compactor pass to another can be used to calculate, estimate or infer a compaction response of material. Changes in another compaction parameter such as density may also be understood to define a compaction response of material with which compactor  10  interacts. The present disclosure should be understood as contemplating any known means for determining a compaction state of material with which compactor  10  interacts, or a change in compaction state from one pass via compactor  10  to another. In the embodiment shown, sensing system  22 , position signal receiver  24  and control system  28 , as well as display  50  and input device  52  are all resident on compactor  10 . It should be appreciated, however, that in other embodiments certain or all of these components/systems might be located remotely from compactor  10 . For instance, electronic control unit  30  might be located at a work site management center or control station, and receiver  24  and sensing system  22  located on an autonomous drone in wireless communication with electronic control unit  30 . 
     Sensing relative rolling resistance may be a practical implementation strategy for determining an energy transfer between compactor  10  and the material being compacted. Energy transfer has been shown to relate to a change in relative compaction when material is worked via compactor  10 , which in turn indicates the material&#39;s compaction response. In one embodiment, electronic control unit  30  may be coupled with a computer readable memory  35 , and may include a memory writing device configured to record rolling resistance data or other compaction response related data thereon, as compactor  10  is passed across a given region of a work area. For example, gross driveline energy output of compactor  10  may be determined, internal losses of compactor  10  subtracted, and the portion of energy expended that relates to an inclination of the surface in a particular region of interest also subtracted. This calculation will allow a determination of the net energy expended to compact material during a measured time or travel distance of compactor  10 . This data is otherwise known as “net compaction energy.” Net compaction energy is indicative of work material compaction response, in particular net compaction energy is negatively correlated with compaction response. Thus, as used herein “indicative of” should not be construed to necessarily mean proportional to or positively correlated with, etc. These data may be recorded on memory  35  for reference in planning subsequent compactor interaction. A suitable apparatus and method for the process of determining rolling resistance of compactor  10  in this general manner, and hence net compaction energy is taught in U.S. Pat. No. 6,188,942 to Corcoran et al. By tracking machine position via the receipt of position signals with receiver  24 , electronic control unit  30  can link compaction response data with position or location data for a work area to allow a varying compaction response of material within a work area to be mapped. Various other means exist for directly or indirectly determining net compaction energy imparted to material via compactor  10 . Certain of these means are identified in copending and commonly owned U.S. patent application Ser. No. 11/517,065, filed Sep. 7, 2006. 
     As mentioned above, machine system  8  may be operated to compact material within a work area in an efficient manner. It is contemplated that machine system  8  may be used such that compaction specifications are met by way of fewer passes via compactor  10 , and in less time than state of the art designs. To this end, control system  28  may be uniquely configured via software and/or hardware control to plan and optionally control operation of compactor  10 , and potentially other machines (not shown) of machine system  8 , for compacting a particular work area to specifications. Computer readable memory  35  may store a compactor interaction planning algorithm for controlling various aspects of interaction between compactor  10  and material within a work area. The planning algorithm may include computer executable code, and electronic control unit  30  may execute the planning algorithm via executing the computer executable code. The term “interaction” as used herein in connection with compactor  10  and material within a work area should be understood to include such factors as compactor speed, compactor travel direction, vibratory output state where vibratory apparatuses are used, number of compactor passes over a particular work area, and still other factors such as orientation of compactor drums  16  and  14  relative to surface features such as seams between different types or grades of material. Electronic control unit  30  may be configured in particular via executing the compactor interaction planning algorithm to determine a compactor interaction plan for compacting a work area. In one embodiment, display  50  is controllably coupled with electronic control unit  30  and is configured to display a map of a work area, and also configured to display at least one of, a compactor coverage of the work area, a compaction response of material within the work area and a compactor interaction plan such as a planned compactor travel path for moving compactor  10  within the work area. Computer readable memory  35 , which may include RAM, ROM, flash memory or any other type of computer readable memory, may also be configured to store compaction specification criteria thereon, the significance of which will be apparent from the following description. In one embodiment, input device  52  may be used for inputting compaction specification criteria which are recorded on computer readable memory  35  via electronic control unit  30 . 
     The operating and compactor interaction planning capabilities of machine system  8  are made possible in part via the unique software and hardware elements of compactor  10 , and in particular control system  28  and sensing system  22 . In one embodiment, operating machine system  8  according to the present disclosure may include receiving electronic data indicative of a varying compaction response of material within a work area. In other words, electronic data may be received by electronic control unit  30 , for example via sensing system  22 , which is indicative of a compaction response of material in each of a plurality of different regions of the work area, the compaction response exhibiting variation among the different regions. Operating machine system  8  may further include linking the electronic data with location data for the work area. For example, position signals received via receiver  24  may be associated with the electronic data indicative of compaction response, allowing determination of compaction response or trends in compaction response for each of a plurality of different regions of the work area. In response to linking the electronic data with location data, electronic control unit  30  may assign each one of at least two different compaction targets to different regions of the work area, as further described herein. 
     As alluded to above, in certain instances there may be more than one way to satisfy compaction specifications. For example, compaction specifications might be met by compacting an entire work area to a uniform compaction state which is considered to be an acceptable compaction state based on a predefined compaction state specification. In other instances, compaction specifications might be satisfied by compacting a certain percentage of a work area to a relatively higher compaction state, while compacting another percentage of the work area to a relatively lower compaction state. Those skilled in the art will appreciate that a number of different plans might be established for compacting a particular work area to a state satisfying compaction specifications. Known strategies, however, by and large assume that material will respond uniformly to compactor interaction. Strategies which recognize variation in compaction response typically provide an operator or controller only with information relevant to compaction progress or identification of fault conditions. The present disclosure recognizes that multiple avenues may exist which each lead to satisfaction of compaction specifications, and enables selection of the most efficient one. By “efficient,” it is meant that the operation of compactor  10  may be planned and/or controlled such that wasted effort compacting material which responds less favorably or more slowly is avoided, whereas material responding more favorably or more rapidly is preferentially worked. Fewer passes via compactor  10 , reduced fuel consumption, reduced operator work time and other improvements may be realized by implementing the teachings set forth herein. These aspects and improvements will be more readily apparent by way of the following description of a hypothetical compaction process. 
     Referring to  FIG. 2 , there is shown display  50  in two different display states, one in the upper portion of  FIG. 2 , and one in the lower portion of  FIG. 2 . A matrix M 1  to be described later is also shown. Display  50  may include a display screen  60  which is configured to display in an operator perceptible format various types of information about a particular work area, the work area being represented in  FIG. 2  via reference letter W. A scale Z is shown displayed on display screen  60 , including different display graphics or colors corresponding to a numerical scale from 1 to 4. In the illustrated embodiment, the numerical scale corresponds to an increasing relative compaction state from number 1 to number 4. Display  50  may also include input device  52 , for example including control buttons, a power on/off switch  56  and a speaker  58  for communicating audible signals to an operator. 
     In the display state shown in the upper portion of  FIG. 2 , relative compaction state for each of a plurality of different regions of the work area is shown after one or more preliminary passes with compactor  10 . Thus, in  FIG. 2 , compactor  10  has compacted or attempted to compact the entire work area W at least once. It will be recalled that electronic control unit  30  may be configured to link location data for the work area with electronic data indicative of the varying compaction response of material within a work area. In the example shown in  FIG. 2 , the work area W is partitioned into twenty-five different cells, each having a graphic display state corresponding to a compaction state on scale Z. Greater or fewer cells could be used, in other embodiments. It may be noted that different regions of the work area, corresponding to different cells, are responding differently to compactor interaction therewith, illustrating a varying compaction response. Display  50  may include another display screen or the like, shown via reference letter X, where a percent goal achieved is shown. In other words, display screen X may be used to display to an operator what percentage of the work area has been compacted to a specified compaction state. 
     The illustration of display  50  shown in the lower portion of  FIG. 2  includes a compactor travel path P 1  through each of the cells of the work area. According to the planned travel path P 1  compactor  10 , shown as an icon on display screen  60 , is to pass across work area W uniformly. In general, operation of machine system  8  according to the present disclosure will commence with at least one, and typically two or three, passes over a work area in a uniform manner to ensure that every region of the work area is compacted at least once. Thus, execution of the compactor interaction planning algorithm via electronic control unit  30  will typically establish a uniform coverage plan or compactor travel plan within work area W for preliminary passes. As further described herein, however, once additional compaction response data is gathered, more complex and non-uniform compactor interaction plans will be established. Stated another way, the compactor interaction plan will be updated in response to additional compaction response data. Also shown in  FIG. 2  is example matrix M 1 , wherein a numerical value is assigned to each of the cells of work area W. Electronic control unit  30  may track compaction progress in each of the cells via matrices. Thus, the leftmost numeral 1 in the top row of matrix M 1  corresponds to the leftmost cell in the top row of the display map of work area W, and so on. 
     Referring also to  FIG. 3 , there is shown a similar illustration of display  50  in another display state, where relative compaction data is displayed graphically for each of the cells of work area W, and yet another display state showing a planned compactor travel path P 2  within work area W. The display state depicted in the upper portion of  FIG. 3  corresponds to a hypothetical compaction state of material within each of the cells of work area W after a compactor pass following travel path P 1 . It will be noted that the percent achieved remains at zero, as shown in display X. A second matrix M 2  is also shown where numerical values corresponding to the updated compaction state of material within each of the cells are tracked via electronic control unit  30 . 
     It will be recalled that electronic control unit  30  will assign different compaction targets to different regions of work area W. It may also be noted that certain cells within work area W changed little, if at all, in relative compaction state after moving compactor  10  along travel path P 1 . These cells are labeled via reference letters G, Q, R, S, T and V in  FIG. 3 . Thus, at the stage depicted in  FIG. 3  electronic control unit  30  may conclude that certain cells are responding poorly, if at all, to compactor interaction. Additional attempts to compact cells G, R, S, T or V may be considered fruitless or at least require more effort and time than is desirable. Assigning each one of the different compaction targets to different regions of the work area may include assigning at least one of a compactor coverage target and a relative compaction target to the different regions of the work area. In other words, in establishing a compactor interaction plan, electronic control unit  30  may decide via executing the compactor interaction planning algorithm to specify a certain compactor coverage for a given cell, a particular relative compaction for a given cell, or both. 
     In the hypothetical example depicted in  FIG. 3 , relative compaction targets are assigned. In particular, a relatively lower relative compaction target is assigned to cells G, Q, R, S, T and V. For example, a target compaction state of 1 might be assigned to each of these cells. Thus, electronic control unit  30  has determined that, at least at the present time, no additional attempt will be made to compact cells G, Q, R, S, T and V. The more promising cells, other than cells G, Q, R, S, T and V, might be assigned a compaction target of 4. In one specific example, assigning the compaction targets might include populating a table stored on memory  35  with location coordinates for each of the cells of work area W. In  FIG. 3 , a matrix M 2  is also shown which indicates relative compaction in each one of the cells of work area W. A third matrix M 3 , illustrates a difference between matrix M 1  and matrix M 2 . The values of matrix M 1  may be subtracted from the values of matrix M 2  to generate a numerical indication of compaction response in each of the cells of the work area. It may be noted that the values in M 3  which correspond to areas P, Q, R, S, T and V are zero, as these areas showed no recent improvement. Once numerical compaction response values are determined, compaction response coordinates for each of the cells may be entered in the table. Compaction targets could then be assigned and also entered into the table, and electronic control unit could process the information stored in the table to establish or update a compactor interaction plan. 
     In one embodiment, assigning the compaction targets may be based on the distribution of cells showing the most promise for reaching an optimal compaction state, such as a compaction state of 4 on scale Z. Assigning the compaction targets could additionally or alternatively be based on a distribution of cells showing the least promise for reaching an optimal compaction state. In other words, electronic control unit  30  may determine that compaction effort should be directed within work area W based not only on how favorably material in different cells is responding, but based also on the relative locations or proximity of favorably responding and/or unfavorably responding cells. It should be noted that larger numbers in matrix M indicate a relatively larger, more favorable compaction response, and relatively smaller numbers indicate a relatively lesser, less favorable compaction response. Cells responding favorably which are located relatively close together could be assigned a compaction target equal to the optimal compaction state 4, for example. Minimal time may be required to reach compaction specifications for material in those cells not only because they appear to be responding well, but also because they can be reached without having to drive compactor  10  across the entire work area. Likewise, favorably responding cells that are relatively far from other favorably responding cells might be assigned to a lower target compaction category, since moving compactor  10  between those cells would require too much time and/or waste effort passing through unfavorably responding cells to reach the favorably responding cells. 
     Once compaction targets are assigned, electronic control unit  30  may determine a compactor travel path based on the assigned compaction targets. For example, electronic control unit  30  could determine the shortest travel path which would allow compacting material in each of the cells assigned to a target compaction state of 4. Alternatively, determining a compactor travel path may include determining a travel path that would avoid each of the cells assigned to a lower target compaction state such as a target compaction state of 1. A more complex determination might also take place, considering additional factors such as number of times compactor  10  would be turned to execute a particular path, slope in the work area, relative soil moisture, or even mat temperature in the case of asphalt compaction. 
     It will be recalled that compaction specification data may be stored on memory  35 . Assigning the different compaction targets may further include reading the stored compaction specification data. Electronic control unit  30  might read compaction specification data stating, for example, that at least 75% of a work area must be at a compaction state of 4, and no more than 10% may be at a compaction state lower than 3, and no more than 5% may be at a compaction state of 1 or lower. The compaction specification data might also specify, for example, that the entire region must be covered via compactor  10  at least once, at least 75% must be covered at least three times, and so on. These examples are of course purely illustrative. Another way to consider the data processing represented in  FIG. 3  is that electronic control unit  30  is reading compaction specification data, receiving electronic data indicative of compaction response for the different cells, then prioritizing compactor interaction with areas that appear to be responding favorably so that compaction specifications may be satisfied as efficiently as possible. The present strategy thus leverages an allowable error rate, defined by the compaction specification data, to optimize efficiency by enabling electronic control unit  30  to proactively decide which cells can be left at a compaction state that is less than an optimal compaction state, and which cells can be quickly compacted to an optimal state. Electronic control unit  30  thus calculates a pattern for differentially compacting cells which satisfies compaction specifications for the overall work area W with as little effort as possible. 
     Referring also now to  FIG. 4 , there is shown display screen  60  as it might appear displaying a compaction state for each of the cells of work area W after a third compactor pass, according to compactor travel path P 2  shown in  FIG. 3 . A matrix M 4  is also shown in  FIG. 4  which represents numerical values determined via electronic control unit  30  and indicating the relative compaction state of material in the individual cells of work area W. Also shown in  FIG. 4  is another matrix M 5 , representing the difference between the values in matrix M 3  and M 2 . In the lower illustration of display  50  in  FIG. 4  is yet another planned compactor travel path P 3 . Compactor travel path P 3  may be established based on the additional compaction response/compaction state data received during the preceding compactor pass(es) according to travel path P 2 . Thus, the compactor interaction plan may be updated after successive passes by way of travel path P 2  through selected cells of work area W. 
     It may be appreciated that the compaction state/response data tracked via electronic control unit  30 , as represented in matrices M 1-5 , can change over time. Thus, areas which might initially be thought to be responding well may turn out later to respond relatively poorly, and vice versa. Thus, preliminary response data associated with one or more preliminary compactor passes within each of the cells may be received, and a preliminary compactor interaction plan established on the basis thereof, represented by way of example in  FIG. 3 . Once additional electronic data indicative of a subsequent compaction response associated with one or more subsequent compactor passes is received for a part or all of the cells of the work area, the compactor interaction plan may be updated. In particular, electronic control unit  30  may compare the electronic data associated with or indicative of a preliminary compaction response with the additional electronic data, and update the compactor interaction plan responsive to comparing the respective data sets. Electronic control unit  30  may be thought of as progressively refining a compactor interaction plan based on the most recent data available. 
     Turning now to  FIG. 5 , there is shown work area W displayed on display screen  60  as it might appear after executing the compactor travel path P 3  shown in  FIG. 4 . It may be noted that 10 of the 25 cells of work area W have a compaction state corresponding to number 4 on scale Z. At this point, a compaction state of 4 has been achieved for approximately 40% of work area W. From the state illustrated in  FIG. 5 , compactor interaction may continue according to progressively updated compactor interaction plans, until compaction specifications are satisfied. For example, additional data may be received for subsequent passes, and the compactor interaction plan updated and executed until a compaction state of 4 for 90% of the work area is achieved. 
     INDUSTRIAL APPLICABILITY 
     Referring to  FIG. 6 , there is shown a flowchart  100  illustrating an example control process according to the present disclosure. The process of flowchart  100  may begin at step  110 , Start or initialization. From step  110 , the process may proceed to step  115  to enter compaction specification data. Compaction specification data may be specified by Department of Transportation regulations, agreed upon by a contractor and customer, etc. It is contemplated that the compaction specifications may include many different parameters, such as compaction state parameters, compactor coverage parameters, density, and combinations of these and other parameters. From step  115 , the process may proceed to step  120  to track machine position, for instance by receiving signals with receiver  24 . From step  120 , the process may proceed to step  125  wherein electronic control unit  30  receives electronic data such as sensor data from sensor  26  indicative of a varying compaction response among the different regions of the work area. Variance in compaction state of the cells in  FIGS. 2-5  represents one example of a hypothetical varying compaction response. From step  125 , the process may proceed to step  130  wherein electronic control unit  30  may output display signals to display  50  such that compactor coverage of the work area is displayed thereon. Examples such as coloring or shading cells of work area W are readily conceived. From step  130 , the process may proceed to step  135  to query whether a minimum coverage specification has been met. It will be recalled that for most compacting work a coverage criterion will be specified, such that every region of a work area is covered at least once, at least twice, etc. If the minimum coverage specification is not met, the process may return to execute steps  120 - 135  again. If yes, the process may proceed ahead to step  140 . 
     At step  140 , electronic control unit  30  may link the sensor data with machine position data, such that the varying compaction response may be mapped to positions of compactor  10  at different locations in the work area. It will be recalled that the work area may be partitioned into cells, and each cell assigned a numerical value corresponding with a relative compaction thereof. Differences among these numerical values indicates a varying compaction response, and changes in the numerical values over time indicate a compaction response associated with a particular cell. Thus, linking the sensor data with location or position data may be understood as associating a numerical compaction state value with a numerical position value(s). From step  140 , the process may proceed to step  145  where electronic control unit  30  may calculate an average return and a most recent return for each of the cells of the work area. In other words, in one embodiment electronic control unit  30  can calculate an average increase in relative compaction per each compactor pass for each cell of the work area. Electronic control unit  30  may also calculate the increase in relative compaction associated with the most recent pass of compactor  10  within each individual cell of the work area. Each of these quantities may be used in establishing a compactor interaction plan for further compacting of the work area. For example, certain areas which preliminarily responded relatively well to compactor interaction may not subsequently respond particularly well to compactor interaction, and it thus might be concluded that relative compaction of those areas is maxed out. Likewise, other areas which initially showed little increase in relative compaction per each compactor pass might be responding relatively better to subsequent compactor passes, and thus could be prioritized for subsequent treatment. 
     From step  145 , the process may proceed to step  150  where electronic control unit  30  will assign different compaction targets to different regions of the work area. For instance, certain areas which have been covered the minimum number of times but respond relatively poorly to compactor interaction might be assigned a low compaction target. Other regions of the work area might be assigned a higher compaction target, where such other regions appear to be more amenable to compaction to an optimal compaction state. 
     From step  150 , the process may proceed to step  155  to determine a compactor travel path. Determining a compactor travel path is one example of determining a compactor interaction plan, as described herein. From step  155 , another round of interaction between compactor  10  and work area W may commence, via the travel path established in step  155  and the process may proceed to step  160  to again track machine position. From step  160 , the process may proceed to step  165  to receive sensor data indicative of a varying compaction response. From step  165  the process may proceed to step  170  to link the sensor data with machine position data, establishing what compaction state or compaction response state is associated with which cell(s) within work area W. From step  175  the process may proceed to step  175  to compare the linked data with the compaction specification data. In other words, in step  175 , electronic control unit  30  may compare actual compaction data, associated with position data, with a compaction specification. Thus, at step  175 , it might be queried whether, for example, at least 90% of work area W is at a compaction state 3, and no more than 5% is at a compaction state 1, etc. From step  175  the process may proceed to step  180  to query whether compaction is complete. If no, the process may return to execute steps  155 - 175  again. If yes, the process may proceed to step  185  to Finish. 
     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 modification might be made to the presently disclosed embodiments without departing from the full and fair scope and spirit of the present disclosure. For example, while the foregoing description emphasizes controlling operation of machine system  8  via commands or displayed suggestions such as compactor travel paths on display  50  to navigate compactor  10  within a work area, the present disclosure is not thereby limited. In other embodiments, rather than suggesting or commanding travel direction, compactor speed, vibratory output state, etc., might be planned via executing the compactor interaction planning algorithm. Thus, rather than commanding/suggesting specific travel paths P 1 , P 2  and P 3 , as described above, electronic control unit  30  might output display commands to display  50  such that a map of the work area indicates uniform coverage by compactor  10 , but at a non-uniform vibratory output and speed. Areas responding poorly might be passed over quickly with a vibratory apparatus of compactor  10  turned off, while more promising areas could be worked more slowly, with vibration turned on. Other aspects, features, and advantages will be apparent upon the examination of the attached drawings and appended claims.