Patent Publication Number: US-2023142590-A1

Title: Robotic lawn mowers

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to U.S. Provisional Patent Application 63/278,079 filed on Nov. 10, 2021, the disclosure of which is incorporated by reference herein in its entirety. 
    
    
     FIELD 
     The present disclosure relates generally to robotic lawn mowers, and more particularly to communication between and amongst a plurality of robotic lawn mowers 
     BACKGROUND 
     Traditionally, lawn mowing was performed by a human operator. The operator moved a lawn mowing machine around a work area. Over time, it has become common to replace the human operator with a robotic lawn mower. Robotic lawn mowers are capable of mowing operations largely without the intervention of operators. In this regard, they reduce time and cost associated with mowing. However, robotic lawn mowers are limited in their mowing capacity as they generally lack effective communication for operating in a group. 
     Accordingly, improved mowing systems which utilize a plurality of robotic lawn mowers would be desired in the art. In particular, mowing systems which allow a plurality of robotic lawn mowers to effectively communicate with one another would be advantageous. 
     SUMMARY 
     Aspects and advantages of the present disclosure will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the technology. 
     In accordance with one embodiment, a method of operating a mowing system is provided. The method includes mowing within a work area, wherein mowing is performed by a robotic lawn mower, and wherein the work area comprises a plurality of base stations each configured to charge the robotic lawn mower; and determining when to charge the robotic lawn mower in view of a current charge level and a current location of the robotic lawn mower. 
     In accordance with one embodiment, a method of operating a mowing system is provided. The method includes mowing within a work area, wherein mowing is performed by a plurality of robotic lawn mowers, and wherein the work area comprises a plurality of base stations each configured to charge the plurality of robotic lawn mowers; and determining when to charge at least one of the plurality of robotic lawn mowers in view of a current charge level and a current location of the at least one of the plurality of robotic lawn mowers, and further in view of a current occupancy of each of the plurality of base stations. 
     In accordance with one embodiment, a method of operating a mowing system is provided. The method includes mowing within a work area using a work plan, wherein mowing is performed by a robotic lawn mower, and wherein the work area comprises a plurality of base stations each configured to charge the robotic lawn mower; determining when to charge the robotic lawn mower in view of a current charge level and a current location of the robotic lawn mower; determining energy consumption of the robotic lawn mower using the work plan; and informing future determinations of when to charge the robotic lawn mower in view of the determined energy consumption of the robotic lawn mower using the work plan. 
     These and other features, aspects and advantages of the present disclosure will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the technology and, together with the description, serve to explain the principles of the technology. 
     Other aspects of the embodiments will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure of the present disclosure, including the best mode of making and using the present systems and methods, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: 
         FIG.  1    is a perspective view of a robotic lawn mower in accordance with an exemplary embodiment of the present disclosure; 
         FIG.  2    is a perspective view of a mowing system including the robotic lawn mower and a base station in accordance with an exemplary embodiment of the present disclosure; 
         FIG.  3    is a schematic of a work area including a plurality of zones in accordance with an exemplary embodiment of the present disclosure; 
         FIG.  4    is a schematic of a work area including a plurality of zones in accordance with an exemplary embodiment of the present disclosure; 
         FIG.  5    is a schematic view of a work area including a robotic lawn mower operating on a work path and a plurality of base stations in accordance with an exemplary embodiment of the present disclosure; 
         FIG.  6    is a flow chart of a method of operating a mowing system in accordance with an exemplary embodiment of the present disclosure; and 
         FIG.  7    is a flow chart of a method of operating a mowing system in accordance with an exemplary embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference now will be made in detail to embodiments of the present disclosure, one or more examples of which are illustrated in the drawings. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations. Moreover, each example is provided by way of explanation, rather than limitation of, the technology. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present technology without departing from the scope or spirit of the claimed technology. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. It should be understood that although certain drawings illustrate hardware and software located within particular devices, these depictions are for illustrative purposes only. Functionality described herein as being performed by one component may be performed by multiple components in a distributed manner. Likewise, functionality performed by multiple components may be consolidated and performed by a single component. In some embodiments, the illustrated components may be combined or divided into separate software, firmware and/or hardware. For example, instead of being located within and performed by a single electronic processor, logic and processing may be distributed among multiple electronic processors. Regardless of how they are combined or divided, hardware and software components may be located on the same computing device or may be distributed among different computing devices connected by one or more networks or other suitable communication links. Similarly, a component described as performing particular functionality may also perform additional functionality not described herein. For example, a device or structure that is “configured” in a certain way is configured in at least that way but may also be configured in ways that are not explicitly listed. 
     Thus, it is intended that the present disclosure covers such modifications and variations as come within the scope of the appended claims and their equivalents. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts. 
     As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. The terms “coupled,” “fixed,” “attached to,” and the like refer to both direct coupling, fixing, or attaching, as well as indirect coupling, fixing, or attaching through one or more intermediate components or features, unless otherwise specified herein. As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive—or and not to an exclusive—or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present). 
     Terms of approximation, such as “about,” “generally,” “approximately,” or “substantially,” include values within ten percent greater or less than the stated value. When used in the context of an angle or direction, such terms include within ten degrees greater or less than the stated angle or direction. For example, “generally vertical” includes directions within ten degrees of vertical in any direction, e.g., clockwise or counter-clockwise. 
     Benefits, other advantages, and solutions to problems are described below with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims. 
     In general, systems and methods described in accordance with one or more embodiments herein can include one or more robotic lawn mowers and a plurality of base stations. Operating protocols can be initiated which determine when the mower(s) charge and even at which of the plurality of base stations charging occurs at. In an embodiment, the determination to charge is based on both the current location of the mower and a charge level of the mower. In a more particular embodiment, the determination can be made further in view of determined distances between the mower(s) and the base stations, updated information from previous mowing operations in the work area, the current work plan, occupancy status of the base stations, or any combination thereof. These and other features of the mowing systems and methods described herein will become apparent in light of the embodiments that follow. 
     By way of non-limiting example, the principal robotic lawn mower(s) can communicate between a base station, which may be disposed at the work area, and the secondary robotic lawn mower(s), acting, e.g., like a middleman between the base station and the secondary robotic lawn mower(s); assigning action items and protocols to the secondary robotic lawn mower(s); delegating responsibilities to the secondary robotic lawn mower(s); relaying information from the secondary robotic lawn mower(s) to the base station or between secondary robotic lawn mowers; storing (or even processing) information associated with one or more of the secondary robotic lawn mower(s); handling disagreements or issues arising between multiple secondary robotic lawn mowers; observing (and optionally documenting) actions taken by the secondary robotic lawn mower(s); or the like. 
     In certain instances, the principal and secondary robotic lawn mowers can be fungible, i.e., include the same hardware and components as one another. In this regard, hierarchical assignment may be designated without deference to structural, hardware, or even software differentiation between the robotic lawn mowers. In such a manner, the principal/secondary hierarchical arrangement may be rearrangeable in response to an operational event. For example, when the principal robotic lawn mower is operating at a sub-threshold charge level, principal status can be delegated to one of the secondary robotic lawn mowers. In certain instances, this designation can be temporarily assigned until the previous principal robotic lawn mower reaches a desired charge, at which time the principal designation can revert to the previous principal robotic lawn mower. In other instances, this designation can remain until such time that the newly appointed principal robotic lawn mower requires charging or another operational event occurs. 
     Using hierarchical schemas, the mowing system can streamline operation of a plurality of robotic lawn mowers without requiring human interaction. In certain instances, machine learning may be implemented to acquire information about the mowing system and improve operational capacity. Machine learning may happen centrally, e.g., at the principal robotic lawn mower or base station, or be decentralized, e.g., split between two or more of the robotic lawn mowers or between one of the robotic lawn mowers and the base station. 
     These and other features of the mowing systems and methods described herein will become apparent in light of the embodiments that follow. 
       FIG.  1    illustrates a view of an exemplary robotic lawn mower  100  as seen in accordance with an exemplary embodiment of the present disclosure. The mower  100  is autonomous, or at least semi-autonomous. The mower  100  can be utilized within a work area to perform a work operation, such as mow grass within the work area, perform trimming operations within the work area, perform hedging operations in the work area, or the like. The mower  100  can generally include a body  102  and a walking element including, e.g., a plurality of wheels  104  coupled to the body  102 . 
     In an embodiment, the mower  100  can further include one or more sensors  106  which can detect an aspect of the mower  100  itself or the surrounding environment. In the depicted embodiment, the sensors  106  are disposed on an outer surface of the body  102 . In another embodiment, the sensors  106  may be disposed under the body  102 . In another embodiment, the sensors  106  may be exposed, e.g., at one or more openings  108  in the body  102 . By way of non-limiting example, the sensors  106  may include one or more of visual sensors, audio sensors, touch sensors such as capacitive sensors, radar sensors, temperature sensors, or the like. 
     In an embodiment, the mower  100  can include a communication element  110 . The communication element  110  can include a wireless communication device. The communication element  110  can communicate with other wireless communication devices, such as other wireless communication devices disposed nearby, such as other wireless communication devices disposed within the work area. While depicted on an exterior portion of the mower  100 , in accordance with an embodiment, at least a portion of the communication element  110 , such as the entire communication element  110 , can be disposed at least partially within the body  102  of the mower  100 . 
       FIG.  2    depicts an exemplary embodiment of the mower  100  at a base station  112 . The base station  112  can generally include a receiving area  114  and a dock  116  which can interface with the mower  100 . In the depicted embodiment, the receiving area  114  includes a plate  118  upon which the mower  100  can reside when interfaced with the dock  116 . In other embodiments, the receiving area  114  can be a portion of a work area  120  in the surrounding environment (i.e., without the plate  118 ). 
     One or more base stations  112  can be disposed within or near the work area  120 . In certain instances, the base station(s)  112  may be disposed near a perimeter of the work area  120  to allow for electrical connectivity. 
       FIG.  3    illustrates an exemplary work area  120  including three different zones—a first zone  120 A, a second zone  120 B, and a third zone  120 C. It should be understood that the number, size and shape of the zones  120 A,  120 B, and  120 C can vary without departing from the scope of this disclosure. A first mower  100 A can be disposed in a first zone  120 A, a second mower  100 B can be disposed in a second zone  120 B, and a third mower  100 C can be disposed in a third zone  120 C. In certain instances, the first, second, and third mowers,  100 A,  100 B, and  100 C can generally remain in their respective zones and perform work operations therein. The first mower  100 A can be performing an operation, e.g., a mowing operation, while travelling along path  122 A. The second mower  100 B can be performing a same or different operation while travelling along path  122 B. The third mower  100  an also be performing a same or different operation while travelling along path  122 C. 
     A first base station  112   a  and a second base station  112   b  can be disposed at the work area  120 . The first base station  112   a  is depicted in the first zone  120 A and the second base station  112   b  is disposed outside of zones  120 A,  120 B, and  120 C but within the surrounding environment. As all three mowers  100 A,  100 B, and  100 C require energy (e.g., recharging), it will be necessary for at least the second and third mowers  100 B and  100 C to leave their respective zones  120 B and  120 C to restore energy levels, e.g., charge. Even the first mower  100 A may not necessarily charge at the base station  112 A despite the base station  112 A being disposed in the first zone  120 A with the first mower  100 A. 
       FIG.  4    illustrates another exemplary work area  120  including three zones—a first zone  120 A, a second zone  120 B, and a third zone  120 C. However, unlike the work area  120  depicted in  FIG.  3   , the work area  120  depicted in  FIG.  4    includes overlapping zones  120 A,  120 B, and  120 C. While only small portion of the zones  120 A,  120 B, and  120 C are shown overlapping, in other embodiments the degree of overlap can be substantially larger. For example, in a particular embodiment the overlap between the zones  120 A,  120 B, and  120 C can be approximately 100%, or even 100%. In an embodiment, the zones  120 A,  120 B, and  120 C can overlap at differing degrees. For instance, by way of non-limiting example, 20% of the first zone  120 A may overlap the second zone  120 B while 40% of the first zone  120 A may overlap the third zone  120 C. By way of another example, 15% of the first zone  120 A can overlap each of the second and third zones  120 B and  120 C, 10% of the second zone  120 B can overlap the first zone  120 A, and 50% of the third zone  120 C can overlap the first zone  120 A. In an embodiment, two of the zones may not overlap while two of the other zones overlap. Further scenarios are possible. 
     Similar to the embodiment depicted in  FIG.  3   , the first mower  100 A is disposed in the first zone  120 A, the second mower  100 B is disposed in the second zone  120 B, and the third mower  100 C is disposed in the third zone  120 C of the work area  120 . However, given that the zones  120 A,  120 B, and  120 C overlap, the first, second, and third mowers  100 A,  100 B, and  100 C are thus operating in potentially conflicting environments where two or more of the robots might interact with one another or even collide. Hierarchical schemas may prevent these problems. 
     The mowers  100  described herein can generally operate using an energy source that becomes depleted during use. For example, in an embodiment, the mowers  100  utilize one or more energy storage units, e.g., batteries, to power a rotatable blade and propel the mower  100 . As the batteries are used, charge levels decrease. At a threshold charge, it becomes necessary to recharge the batteries in order to continue the mowing operation. Accordingly, an operating protocol for charging the mowers must be implemented. 
       FIG.  5    illustrates a schematic view of a mower  100  disposed in the work area  120  and operating in view of a work plan including a work path  122 . The work plan may also include, for example, instructions to engage or disengage the mower blade, raise, or lower the mower blade height, increase or decrease mower blade speed, increase or decrease propelling speed, the like, or any combination thereof. 
     The exemplary work path  122  depicted in  FIG.  5    includes a generally winding path that has a first path portion  123   a  disposed adjacent to the first base station  112   a  and a second path portion  123   b  disposed adjacent to the second base station  112   b.  It should be understood that the exemplary work path  122  depicted in  FIG.  5    is shown only for purpose of illustration and does not limit the shapes and configurations of the potential work paths  122  contemplated herein. 
     The first and second path portions  123   a  and  123   b  can each include locations or areas of the work path  122  that are within a range of the base stations  112   a  and  112   b,  respectively. This can include, for instance, areas along the work path  122  which are disposed within a prescribed distance of the base stations  112 , predetermined point locations along the work path  122 , predetermined areal locations along the work path  122 , or any combination thereof. By way of example, the first path portion  123   a  is shown as an aerial location defined by a distance relative to the first base station  112   a.  The portions of the work path  122  disposed within the first path portion  123   a  are shown in solid lines for understanding. The second path portion  123   b  is shown as a predetermined point location within the work area  120 . 
     When the mower  100  encounters either of the path portions  123   a  or  123   b,  a determination may be made about whether to charge the mower  100  at the associated base station  112   a  or  112   b,  respectively, or to continue along the work path  122 . In an embodiment, this determination of whether to charge at the nearby base station  112 , i.e., when to charge, is made in view of a current charge level of the mower  100 . In another embodiment, this determination is made in view of the work plan, e.g., the work path  122 . More particularly, the determination may be made in view of the distance along the work path  122  between the current location and the next path portion, e.g., path portion  123   b.  If the distance to the next path portion  123   b  is less than a threshold value such that the mower  100  can reach the second base station  112   b,  the determination may be made to pass through the first path portion  123   a  and instead move to the second path portion  123   b.  Once reaching the second path portion  123   b,  the mower  100  can either charge, or determine whether to pass through the second path portion  123   b,  instead moving to a third path portion (not illustrated). In certain instances, the third path portion (not illustrated) may even be the first path portion  123   a  as shown by the work path  122  reentering the first path portion  123   a  after passing through the second path portion  123   b.    
     In certain instances, the mowing system described herein can operate using a plurality of mowers as described above. In accordance with an embodiment, the determination of when to charge the mower  100  can be made in view of a current occupancy status of the base station  112   a  or  112   b  disposed adjacent to the path portion  123   a  or  123   b,  respectively. By way of non-limiting example, if the mower  100  is entering the first path portion  123   a  associated with the first base station  112   a  (and the first base station  112   a  is not occupied by another mower) and has enough charge to make it to the second path portion  123   b  associated with the second base station  112   b  (and the second base station  112   b  is occupied by another mower) but the mower  100  does not have enough charge to make it to the third path portion, the mower  100  may stop at the first base station  112   a  to recharge. In certain instances, recharge at the first base station  112   a  may include a full recharge. In other instances, recharge at the second base station  112   a  may include only a partial recharge. By way of example, if the mower  100  only has 100 yards remaining on its work path  122  before completing the mowing operation and enough energy to mow only 75 yards, the time the mower  100  spends at the first base station  112   a  may be just enough to get the mower to 100 yards of mowing charge (and an optional additional safety charge amount). In this regard, the mower  100  can complete the mowing operation quicker and receive a full charge at a future base station  112  without leaving a portion of the work path  122  un-mowed for an extended duration. 
       FIG.  6    is a flow chart  600  of a method of operating a mowing system in accordance with an embodiment. The method  600  can generally include a step  602  of mowing within a work area using a robotic lawn mower. The work area includes a plurality of base stations each configured to charge the robotic lawn mower. The step  602  of mowing within the work area can be performed using a work plan. The work plan can include instructions informing aspects of operation of the mower. For instance, the instructions can inform blade height, blade speed, motor current draw, propulsion speeds, and the like. The instructions can generate a work path along which the mower travels. The mower can utilize one or more implements to stay on the work path. For example, the mower may utilize global positioning satellite (GPS) systems to navigate along the work path, e.g., using way points or the like. In certain instances, the mower can utilize a compass, an odometer, or the like which may allow the mower to maintain a preset course over a prescribed distance and adjust course as necessary to stay on the work path. 
     In certain instances, the step  602  may be performed with input from a centralized, or otherwise external, source. For example, one or more of the base stations may communicate with the mower. Alternatively, a smart device, such as a smart phone, may be operated by a user to control the mower at step  602 . For example, the user may enter a preferred navigation path or protocol which can be communicated to the mower for performing step  602 . 
     It should be noted that the location of the base stations within the work area may be preset prior to the mowing operation. The locations of the base stations may be either manually entered into the mowing system or determined using a base station location discovery protocol. In such a manner, step  602  can be performed with the relative positions of the mower and the base stations being known. 
     During mowing operations, the mower necessarily expends energy. As such, it is necessary to charge the mower. For large work areas, charging may be performed prior to completion of the mowing operation. For smaller work areas, it may be possible to complete the mowing operation on a single charge. Regardless, determining the proper charging location, e.g., base station, for charging may be necessary when the mowing system includes a plurality of base stations. In this regard, the method  600  can further include a step  604  of determining when to charge the robotic lawn mower. The step  604  may be performed in view of both a current charge level and a current location of the mower. In this regard, the decision to charge the mower is not single-factor dependent. Instead, a multi-factor determination protocol is utilized which determines not only the charge level of the mower but also the current location of the mower. If the mower is within a prescribed distance, or at a predetermined location, relative to one of the base stations and the charge level is below a certain threshold, the mower may dock with the base station to charge. If, however, the mower is not within the prescribed distance, or at the predetermined location, or if the charge level is not below the threshold, the mower may continue with the mowing operation as described at step  602 . 
     Step  604  may be performed by the mower. That is, the mower may continuously or periodically check charge level. For example, the mower may check its charge level when entering a path portion associated with a base station. As described above, the mower can then determine whether to charge at that base station. 
     Step  604  may alternatively be performed by the base station. That is, the base station may monitor the charge level of the mower. By way of example, the base station can determine the charge level of the mower when the mower enters the path portion associated with the base station. If the charge is below the threshold, the base station can instruct the mower to dock with and charge at the base station. 
     Step  604  may alternatively be performed by a combination of the mower and the base station. For instance, by way of non-limiting example, the base station can monitor the position of the mower and the mower can monitor its own charge level. The mower and base station can communicate this information therebetween and together arrive at a decision to charge or continue mowing. 
     In an embodiment, the method  600  can further include a step of monitoring the current location of the mower and determining a distance between the current location and at least one of the plurality of base stations. This step can be performed by either, or both, of the base station and mower. In an embodiment, determining the distance between the current location and at least one of the plurality of base stations can include determining a first distance between the current location and a first base station and determining a second distance between the current location and a second base station. In certain instances, the first and second distances can be distances as measured along the work path. In other instances, the first and second distances can be straight-line distances, i.e., shortest route distances. While the determination of when to charge described in the method  600  may be performed while keeping the mower on the work path, in some instances the mower can deviate from the work path to arrive at the base station for charging. 
     The first and second distances can be used to determine when to charge the mower. For instance, if the second distance exceeds a current capacity of the mower, the mower will charge at the first base station. If, however, the second distance does not exceed a current capacity of the mower, the mower may charge at either or both of the first and second base stations. 
     As described above, the determination to charge the mower at step  604  can be based on current charge level and location of the mower. In an embodiment, the determination at step  604  can be performed further in view of the determined distance and a current work plan of the mower. In this regard, the decision of when to charge the mower can be made with respect to a more complete understanding of the work plan. 
     In an embodiment, the mower may reserve a base station for charging after making a determination to charge. For example, if the mower decides to pass the first base station in order to charge at a second base station, the mower can reserve the second base station in advance, to prevent other mowers which may be utilized in the work area from docking with the second base station. This may be useful when the mowing system is operating with a plurality of mowers. 
     In an embodiment, the mowing system can include a plurality of mowers. The method  600  described herein can be utilized to determine charging protocols for each of the mowers. 
     In some instances, it may be helpful to update information associated with the mowing system or work area during or after completion of a mowing operation. For example, some work areas may include steep slopes that require elevated energy usage to traverse. If a mower experiences a higher-than-expected energy usage while traversing the steep slope, the determination to pass one base station for another may not be appropriate. That is, the mower may not make it to the next base station. In this regard, the mowing system can introduce a learning function whereby the mowers determine energy consumption using the work plan and inform future determinations of when to charge in view of the determined energy consumption. In such a manner, the mowers may more accurately maneuver between base stations to achieve an optimal charging protocol. 
     Grass grows at different rates based on a wide factor of environmental considerations. For instance, by way of another non-limiting example, grass growth rates may be influenced by season—e.g., temperature, sun exposure, moisture, etc. Over the course of several mowing operations, patterns relating to the energy consumption may emerge. For instance, in summer months the energy required to mow a work area may be higher than required to mow the same work area in the fall. By determining energy consumption, the mowing system can inform future determinations of when to charge. That is, for example, in summer months when current draw required to rotate the cutting blades is higher, the mower may charge at a first base station and not wait to reach a second base station which may be suitable for mowing operations in the fall when grass height is less. Similarly, the mower may decide to charge sooner in wet seasons which require greater energy to traverse the work area and greater energy to cut the grass. By storing information of energy usage, the mowing system may even be able to compare the energy usage against known energy usage rates. In this regard, the mowing system can determine initial energy usage per unit of mowing and then inform the remainder of that mowing operation based on the information associated with the initial energy usage. By way of example, if the initial energy draw is high as a result of wet conditions, the work plan can be adjusted to correspond with a previous work plan that was formed in view of previous conditions with a similar energy draw. 
     In one or more embodiments, the mowing system can map energy consumptions at different locations within the work area. In such a manner, the mowing system can inform decisions regarding when to charge the mower in view of known energy usage rates. By way of example, the work path may be adjusted to laterally traverse steep slopes rather than continuously climb and descend along the steep slopes. Similarly, areas where grass growth rates are known to be low (e.g., under trees) may utilize slower blade speed to conserve energy while areas where grass growth rates are known to be high (e.g., in open fields) may utilize higher blade speeds. By mapping the energy consumption at the different locations, these different mowing protocols can be employed. Further, these mowing protocols can be employed also in consideration of the location of the base stations for charging. 
       FIG.  7    illustrates a method  700  of operating a mowing system including a step  702  of mowing within a work area using a work plan. Mowing can be performed by a robotic lawn mower. The work area can include a plurality of base stations each configured to charge the mower. The method  700  can further include a step  704  of determining when to charge the mower in view of a current charge level and a current location of the mower. The method  700  can further include a step  706  of determining energy consumption of the mower using the work plan. The method  700  can further include a step  708  of informing future determinations of when to charge the mower in view of the determined energy consumption of the mower using the plan. 
     As described above, determining energy consumption at step  706  may allow the mower to more accurately make decisions regarding charging protocols. By informing future determinations, the mowing system can improve and optimize over time in view of energy considerations. 
     Furthermore, when a plurality of mowers are utilized together in the work area, the step  706  of determining energy consumption may be utilized to best apportion zones within the work area. 
     Further aspects of the disclosure are provided by one or more of the following embodiments: 
     Embodiment 1. A method of operating a mowing system, the method comprising: mowing within a work area, wherein mowing is performed by a robotic lawn mower, and wherein the work area comprises a plurality of base stations each configured to charge the robotic lawn mower; and determining when to charge the robotic lawn mower in view of a current charge level and a current location of the robotic lawn mower. 
     Embodiment 2. The method of any one or more of the embodiments, wherein determining when to charge is performed by the robotic lawn mower, at least one of the plurality of base stations, or a combination thereof. 
     Embodiment 3. The method of any one or more of the embodiments, further comprising monitoring the current location of the robotic lawn mower; and determining a distance between the current location and at least one of the plurality of base stations. 
     Embodiment 4. The method of any one or more of the embodiments, wherein determining when to charge is performed in view of the current charge level, the determined distance, and a current work plan of the robotic lawn mower. 
     Embodiment 5. The method of any one or more of the embodiments, wherein determining the distance is performed by determining a first distance between the current location and a first base station of the plurality of base stations and determining a second distance between the current location and a second base station of the plurality of base stations. 
     Embodiment 6. The method of any one or more of the embodiments, further comprising determining at which of the plurality of base stations to charge the robotic lawn mower in view of the determined first distance and the determined second distance. 
     Embodiment 7. The method of any one or more of the embodiments, wherein the mowing system comprises a plurality of robotic lawn mowers, and wherein the method further comprises determining when to charge each of the plurality of robotic lawn mowers in view of a current charge level and a current location of each of the plurality of robotic lawn mowers. 
     Embodiment 8. The method of any one or more of the embodiments, wherein determining when to charge each of the plurality of robotic lawn mowers is performed further in view of a current occupancy of each of the plurality of base stations. 
     Embodiment 9. The method of any one or more of the embodiments, wherein the method further comprises determining at which of the plurality of base stations to charge each of the plurality of robotic lawn mowers in view of a current occupancy of each of the plurality of base stations. 
     Embodiment 10. The method of any one or more of the embodiments, further comprising: determining energy consumption of the robotic lawn mower when mowing within the work area; and updating information associated with determining when to charge the robotic lawn mower in view of the determined energy consumption. 
     Embodiment 11. A method of operating a mowing system, the method comprising: mowing within a work area, wherein mowing is performed by a plurality of robotic lawn mowers, and wherein the work area comprises a plurality of base stations each configured to charge the plurality of robotic lawn mowers; determining when to charge at least one of the plurality of robotic lawn mowers in view of a current charge level and a current location of the at least one of the plurality of robotic lawn mowers, and further in view of a current occupancy of each of the plurality of base stations. 
     Embodiment 12. The method of any one or more of the embodiments, wherein determining when to charge is performed further in view of determined energy consumption information associated with the work area. 
     Embodiment 13. The method of any one or more of the embodiments, wherein the method further comprising: determining energy consumption of at least one of the plurality of robotic lawn mowers when mowing within the work area; and updating information associated with determining when to charge the at least one of the plurality of robotic lawn mowers in view of the determined energy consumption. 
     Embodiment 14. The method of any one or more of the embodiments, wherein the plurality of base stations and the plurality of robotic lawn mowers form a network and communicate via a communication protocol. 
     Embodiment 15. The method of any one or more of the embodiments, wherein the communication protocol comprises a Bluetooth Low Energy (BLE) protocol, a Zigbee protocol, Lange Range (LoRa) protocol, a radio-frequency protocol, or Wi-Fi. 
     Embodiment 16. The method of any one or more of the embodiments, wherein the robotic lawn mowers communicate bidirectionally with each other, and wherein each of the plurality of robotic lawn mowers is configured to: determine a command for one of the other robotic lawn mowers based on data captured by a sensor; and provide the command to the one of the other robotic lawn mowers. 
     Embodiment 17. The method of any one or more of the embodiments, wherein the robotic lawn mowers are connected to form a chain of robotic lawn mowers where data is unidirectionally transferred from one of the plurality of base stations through the chain of robotic lawn mowers. 
     Embodiment 18. The method of any one or more of the embodiments, wherein each of the plurality of base stations is configures to act as a master for each of the plurality of robotic lawn mowers, and wherein each of the plurality of robotic lawn mowers is configured to act as a slave to each of the plurality of base stations. 
     Embodiment 19. The method of any one or more of the embodiments, wherein each of the plurality of robotic lawn mowers is configured to provide sensor data and location data to the other robotic lawn mowers via the plurality of base stations. 
     Embodiment 20. The method of any one or more of the embodiments, wherein the sensor data is captured by a sensor associated with the respective one of the plurality of robotic lawn mowers, and wherein the location data captured by a geolocation device associated with the respective one of the plurality of robotic lawn mowers. 
     Embodiment 21. The method of any one or more of the embodiments, wherein each of the plurality of robotic lawn mowers is configured to: determine location data relative to at least one of the plurality of base stations, and determine, based on the location data, an optimize a path through the work area. 
     Embodiment 22. The method of any one or more of the embodiments, wherein each of the plurality of base stations is configured to relay communications through at least one of the other robotic lawn mowers to one of the plurality of robotic lawn mowers when it is out of a broadcast range of the respective base station. 
     Embodiment 23. The method of any one or more of the embodiments, wherein each of the plurality of robotic lawn mowers is configured to connect to a different one of the plurality of base stations when a malfunction in a connected on of the plurality of base stations is determined. 
     Embodiment 24. The method of any one or more of the embodiments, wherein each of the plurality of base stations comprises a geolocation device and is configured to provide respective location data to each of the plurality of robotic lawn mowers. 
     Embodiment 25. A method of operating a mowing system, the method comprising: mowing within a work area using a work plan, wherein mowing is performed by a robotic lawn mower, and wherein the work area comprises a plurality of base stations each configured to charge the robotic lawn mower; determining when to charge the robotic lawn mower in view of a current charge level and a current location of the robotic lawn mower; determining energy consumption of the robotic lawn mower using the work plan; and informing future determinations of when to charge the robotic lawn mower in view of the determined energy consumption of the robotic lawn mower using the work plan. 
     Embodiment 26. The method of any one or more of the embodiments, wherein determining energy consumption comprises mapping energy consumption at different locations within the work area. 
     Embodiment 27. The method of any one or more of the embodiments, wherein informing future determinations of when to charge is performed in view of a work path of the work plan and the mapped energy consumption along the work path. 
     Embodiment 28. The method of any one or more of the embodiments, wherein the mowing system comprises a plurality of robotic lawn mowers, and wherein the method further comprises determining at which of the plurality of base stations to charge each of the plurality of robotic lawn mowers in view of a current occupancy of each of the plurality of base stations. 
     Embodiment 29. The method of any one or more of the embodiments, wherein the method further comprises performing additional mowing within the work area, and wherein determining at which of the plurality of base stations to charge each of the plurality of robotic lawn mowers during the additional mowing is further determined in view of the informed future determination. 
     Embodiment 30. The method of any one or more of the embodiments, further comprising monitoring the current location of the robotic lawn mower; and determining a distance between the current location and at least one of the plurality of base stations. 
     Embodiment 31. The method of any one or more of the embodiments, wherein determining the distance is performed by determining a first distance between the current location and a first base station of the plurality of base stations and determining a second distance between the current location and a second base station of the plurality of base stations, and wherein the method further comprises determining at which of the plurality of base stations to charge the robotic lawn mower in view of the determined first distance and the determined second distance. 
     This written description uses examples, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. 
     Thus, embodiments described herein provide, among other things, methods of operating a mowing system. Various features and advantages are set forth in the following claims.