TECHNICAL FIELD

[0001] The present disclosure relates to forestry machines. In particular, the present disclosure relates to a forwarder shuttle for use in forestry operations.

BACKGROUND

[0002] Conventional forestry operations comprise steps of felling trees and harvesting logs, collecting the logs and transporting the logs to an unloading location wherefrom they are shipped (e.g. by truck or train) to a processing plant for further processing.

[0003] A representative example of a forestry operation comprises a number of forestry machines carrying out these forestry operations. A harvester may operate to fell trees and process logs with a processing head, and deposit the logs onto the ground. A forwarder typically having a log grapple on a crane may then collect these logs and place them into a log loading compartment of the forwarder for transporting the logs to the unloading location. Then, at the unloading location, the forwarder’s crane may unload the logs from the forwarder and sort the logs into separate piles on the basis of type, quality, etc.

[0004] It is desirable to optimise the efficiency of forestry operations, which may involve maximising an amount of harvested logs in a working day, and maximising the quality thereof.

[0005] In recent times, the environmental restrictions on forestry operations have been enhanced, which can negatively impact the efficiency of forestry operations.

[0006] A further environmental consideration in forestry operations is the so-called ‘ground impact’ of the forestry machines carrying out the forestry operations. The ground impact is the amount of displaced ground (earth and mud) resulting from the driving of the forestry machines. Forestry machines can weigh in excess of 20 tonnes, and can carry a load of logs exceeding a further 15 tonnes. Thus, the ground impact of forestry operations can be great.

[0007] A majority of the ground impact may be caused by the driving of forwarders back and forth from the harvester during the forestry operations being fully loaded with logs. Thus, there is a desire to improve the design of forwarders to reduce the overall environmental impact of a forestry operation.

[0008] The weight of forwarders may be reduced by not including a log grapple crane on the forwarder and instead equipping the harvester with an interchangeable processing head such that the harvester can equip a log grapple to load logs onto the forwarder. [0009] Furthermore, the efficiency of the forestry operations may be further improved by adding more forwarders to the operation such that the harvester always has a forwarder available for loading.

SUMMARY OF INVENTION

[0010] According to an aspect of the present disclosure, there is provided a self-driving log forwarder shuttle system, comprising a self-driving log forwarder shuttle and a mobile charging station.

[0011] The self-driving log forwarding shuttle comprises an electrical energy storage, a log loading compartment for receiving harvested logs, a traction arrangement powered by the electrical energy storage and configured to drive the shuttle, and a controller connected to the traction arrangement and configured to control the driving of the shuttle.

[0012] The electrical energy storage may be one or a bank of batteries, capacitors and/or the like configured to be charged or discharged via connection to an electrical energy generator or an electrical load, respectively.

[0013] The log loading compartment may be a cage-like holder constituting an upper platform of the forwarder shuttle, configured to receive logs and then retain them during a driving of the shuttle. The log loading compartment may be configured as a series of upwardly extending arms delimiting a holding pen for logs laid in a same orientation, as with conventional forwarder forestry machines.

[0014] The mobile charging station comprises a fuel reservoir, an electrical energy generator fuelled by a fuel from the fuel reservoir, and a traction arrangement configured to drive the mobile charging station, which may be powered by the electrical energy generator.

[0015] The traction arrangement may comprise wheels, a continuous track or some combination thereof. Forestry sites may contain challenging terrain such as felled trees, boulders, highly irregular topologies, water-logged tracks, etc. Thus, it is preferable for the traction arrangement to be configured for all-terrain driving, whilst being easily reparable in case of damage during operation, and for the traction arrangement to have a high surface area relative to its size to reduce ground impact of the shuttle.

[0016] According to this aspect of the present invention, the shuttle and mobile charging station each comprise a respective electrical coupling configured to mutually couple, thereby enabling charging of the electrical energy storage of the shuttle by the electrical energy generator of the mobile charging station.

[0017] By providing a mobile charging station as part of the self-driving log forwarder shuttle system, having an electrical energy generator and a traction arrangement for moving the mobile charging station, the shuttles in the system may be charged in various places, such as different places throughout the forestry site, using the same fuel source in the mobile charging station. Thus, the mobile charging station can be driven to the forestry site and therearound in a manner that allows for charging of the self-driving log forwarder shuttles whilst they are conducting forestry operations in the forestry site.

[0018] For example, the mobile charging station may be driven to a log harvesting location wherein one or more shuttles is having harvested logs loaded thereon. That is, a harvester forestry machine may be felling trees as part of a forestry operation and directly loading said harvested logs into the log loading compartment of the shuttle at a same time that the mobile charging station is charging the shuttle.

[0019] As a consequence, the shuttles do not need to carry electrical energy storages that are large enough to last throughout the entire forestry operation (e.g. throughout the entire working day of taking harvested logs from a harvesting location to an unloading location). Thus, the weight of the self-driving log forwarder shuttles is significantly reduced. Therefore, the ground impact on the driving paths caused by the driving of the shuttles is consequently reduced. Hence, the overall environmental impact of the forestry operation that the self-driving log forwarder shuttle system is a part of is reduced.

[0020] Furthermore, the shuttles do not need to return to a static or (semi-)permanent charging location which may be far from the ongoing forestry operation in order to replenish their charge. Instead, the mobile charging station can be co-ordinated and navigated in such a way that the shuttles are charged during the course of the forestry operations carried out by the shuttle system (e.g. during loading and/or unloading of logs onto or from the log loading compartment). Put another way, the shuttles according to the present aspect are charged ‘on the job’. Hence, interruptions to the forestry operations are reduced and/or a fewer number of shuttles are required to carry out the forestry operations at a required pace. Thus, the efficiency of the forestry operations is greatly enhanced.

[0021] In some examples, the mobile charging station may be part of a forestry machine such as a harvester. In such examples, the harvester acting as the mobile charging station may be the same harvester that is harvesting logs and loading logs directly onto the shuttle at a same time as charging the shuttle. Such an arrangement may advantageously ensure that the shuttles can be charged whilst they are being loaded with logs at the harvesting site.

[0022] In some conventional examples, in order to ensure that a harvester is not required to stop felling and processing logs, the forwarder may not always accompany the harvester, and during the times the forwarder is not available, logs are placed onto the ground for later collection.

[0023] However, by directly loading the shuttles of the present invention with logs during their charging, a work efficiency of the forestry operations can be improved, as it is not required to lift the logs off of the ground again, which can take unnecessary time. Energy efficiency of the operations may also be improved, as the logs do not need to be lifted again to be brought onto the shuttles.

[0024] Additionally or alternatively, the mobile charging station may be part of an unloading crane configured to unload logs from the log loading compartment, e.g. at an unloading location. Thus, the shutles may be charged at a same time as having logs unloaded therefrom. Loading and unloading of logs to and from the shutle are times when the shutles are typically not moving or only slowly moving, thus allowing an easy maintenance of an electrical coupling between the shutle and the mobile charging station.

[0025] In some examples, the controller may be further configured to control the driving of the shutle based on a driving path. The driving path may be a set of directions from an origin to a destination, a series of navigation points, a set of driving instructions, or some other representation of a path through a forestry site that enables the self-driving shutle to navigate along said path through the forestry site.

[0026] The driving path may be determined by the controller itself, i.e. locally. For example, the shutle may further comprise one or more navigation sensors connected to the controller, the navigation sensors being configured to collect information about the driving environment around the shutle. Then, the controller may be configured to control the driving of the shutle based on the collected information from the one or more navigation sensors.

[0027] The navigation sensors may be RGB camera(s), stereo camera(s), LIDAR (light detection and ranging) sensor(s), infrared camera(s) and/or some other form of sensor configured to collect information suitable for assisting in the navigation of the shutle.

[0028] The collected information may include detected objects, distances, path identifiers or markers, heat signatures, and/or some other information that may inform the navigation of the self-driving shutle along the driving path through the forestry site. The controller may further comprise means for processing, and may apply one or more artificial intelligence (Al) or machine learning (ML) techniques to the collected information in order to determine a driving path entirely locally without requiring any remote control or intervention from a human operator.

[0029] The driving path may be dynamically determined in this way, in such a way that the controller determines a driving path and navigates along said driving path substantially contemporaneously. This allows the self-driving shutle to respond to a changing forestry environment during the course of forestry operations, which can be impacted by weather, path degradation (i.e., a path can become too worn or waterlogged to reliably navigate down) and the like without manual intervention.

[0030] In some examples, the driving path may be provided to the controller from an external device such as a computing device in another piece of machinery in the forestry site, a remote computing environment, or some other computing environment having hardware and/or software configured to determine a driving path for one or more of the shutles.

[0031] The external device may have access to a collated database of information about the forestry site, which may be provided in advance (e.g. by human operators or autonomous monitoring systems) or gathered in real time. For example, the forestry site may have a forestry monitoring system monitoring the forestry site and feeding information to a computing device and determine driving path decisions for one or more of the shuttles based on the collected information about the forestry site.

[0032] The external device may, in some examples, be comprised in the mobile charging station or in a same piece of machine that the mobile charging station is comprised within. For example, the external device may be a harvester, e.g. a same harvester that loads logs onto the shuttle and/or charges the shuttle.

[0033] In such examples, the driving path (i.e. information representative thereof) may be provided to the controller of the shuttle at a same time as charging. Thus, the transfer can be carried out using short-range wireless communications or wired connections which may be connected at a same time as charging, or even via the same coupling. Therefore, the shuttle may not need to be configured for long range wireless communications, which may further reduce the weight of the shuttle as a transmitter may not be required. Furthermore, forestry sites can be relatively remote and therefore poorly covered by communications networks such as 3G/4G/5G networks etc.

[0034] The external device may be entirely remote from the forestry site in some examples. For example, the external device may be realised as part of a cloud computing server environment. In such an arrangement, the external device may be configured for long distance data communications, e.g. by having a transmitter configured to transmit the driving path to the controller of the shuttle. Alternatively, the external device may transmit the driving path to another forestry machine such as the harvester or unloading crane, which is configured to subsequently forward or relay the driving path to the shuttle via short-range wireless or wired communications.

[0035] By carrying out calculations of driving paths in a remote external device, the computing power required on site at the forestry site is reduced. Thus, the driving paths may be improved by application of more computationally expensive Al or ML techniques.

[0036] When determining driving paths, the controller or the external device may consider the environmental impact of the forestry operations, the quality of harvested trees, the efficiency and speed of the forestry operations and/or other criteria that may be prioritised by those undertaking the forestry operations in question.

[0037] For example, if the environmental impact of the forestry operations is a priority, the ground impact of the shuttles in the shuttle system can be further reduced by distributing the shuttles amongst possible available driving paths so that a substantially even usage of each possible driving path is achieved.

[0038] If the quality of harvested trees is a priority, the straightness of trees may be measured as a metric of their quality, e.g. by the shuttles themselves or by a forestry monitoring system, such as one including unmanned aerial vehicles (UAVs), and then a driving path for a harvester and the shuttles can be determined that optimises a path through the highest quality trees. [0039] As will be appreciated, the varying conditions in a forestry site or changing priorities of the forestry operations can impact the driving path determined for the shuttles in the system. An Al system may be trained in such a way that dynamically determines a best driving path for a shuttle given all available information collected by the shuttles and/or or the wider system.

[0040] According to some examples, the self-driving log forwarding shuttle may further comprise an energy monitor for monitoring an electrical energy level of the electrical energy storage of the shuttle. The driving path may then be determined by the controller further based at least in part on the electrical energy level of the electrical energy storage.

[0041] By having the driving path of the self-driving shuttle be informed by an electrical energy level of the electrical energy storage of the shuttle, the controller of the shuttle can be configured to navigate the shuttle towards the mobile charging station in response to a determination that the electrical energy level reduces to below a minimum level. In some other examples, the mobile charging station may be navigated to the shuttle instead of the shuttle being navigated to the mobile charging station, the mobile charging station being operated by a human or being itself self-driving. [0042] To assist with such an operation, the mobile charging station may transmit or otherwise communicate its position directly or indirectly to the shuttles in the system. Thus, the controller may be configured to estimate (e.g. informed by measurements) an amount of electrical energy required in the electrical energy storage in order for the shuttle to navigate to the mobile charging station. This estimation may additionally or alternatively be carried out by the external device and may be informed by an application of Al techniques, which may further determine and consider a predicted motion of the mobile charging station, for example.

[0043] The controller (or the external device) may be further configured to calculate or estimate a travel time between two points, e.g. an origin and a destination. The origin may be a start of a driving path and the destination may be an end of the driving path. Either the origin or the destination may instead be locations at an intermediate location along a predefined driving path (i.e. a path created through the forestry site). The travel time may be used by the system to estimate a time of arrival for the shuttle at the destination.

[0044] The travel time may therefore be used, e.g. in combination with the electrical energy level in the electrical energy storage, to inform whether the driving path of the shuttle should be adjusted, for example. In some examples, the travel time may be used to estimate an arrival time of a shuttle at a harvester and this information may be sent to the harvester. Thus, the harvester may advantageously stay informed of when the next available shuttle will be arriving, and optimise harvesting operations accordingly.

[0045] According to some examples, the log loading compartment may be positionable relative to the traction arrangement. That is, the log loading compartment may be connected to the traction arrangement by one or more movable elements that enable the relative positions of the log loading compartment and the traction arrangement to be varied.

[0046] For example, the log loading compartment may be mounted on a rail, a track, or a slideable component that is subsequently connected to the traction arrangement of the shuttle. Therefore, the log loading compartment may be slideable along the shuttle. In some examples, the log loading compartment may be slideable from a shuttle to another shuttle, thus enabling a transfer of logs between shuttles via a transfer of a removeable log loading compartment having logs therein.

[0047] Additionally, or alternatively, the log loading compartment may be pivotable via a raising piston or similar raising component that lifts one end of the loading compartment above another, thus allowing the logs to be dumped out of the log loading compartment under the action of gravity.

[0048] In some examples, the log loading compartment may be rotatable relative to the traction arrangement. The rotation of the log loading compartment may be in a plane of the traction arrangement, i.e. clockwise or anticlockwise when a shuttle is viewed from above.

[0049] The position of the log loading compartment may be manually controlled by operation of controls on the shuttle itself (e.g. switches, buttons, levers, etc.), remotely controlled with an external control device (e.g. a standalone device or comprised in another machine such as a harvester), or controlled entirely locally. Thus, the controller may be further configured to control a position of the log loading compartment and such controls may either be determined by the controller itself or provided thereto from an external device.

[0050] For example, the log loading compartment may be rotated to assist in the reception of a log, by orienting the log loading compartment along an axis of the incoming log. In some examples, a harvester may communicate a position of its processing head to the shuttle being loaded and/or an orientation thereof. The harvester may send this information to the shuttle being loaded, e.g. to the controller therein. Based on this information, the controller of the shuttle may control the position of the log loading compartment to facilitate an expedient loading of the log into the log loading compartment. Additionally, or alternatively, the shuttle may utilise a sensor to detect the position and/or orientation of an incoming log.

[0051] In some examples, the log loading compartment may be positioned relative to the traction arrangement in such a way as to optimise the balance of the shuttle and/or maintenance of the logs safely in the log loading compartment. In some occasions, the driving path (i.e. along a logging road) may be irregular, sloped, have obstructions to drive over, and the like, which may risk a displacement of logs from the log loading compartment, or a tipping or flipping of the shuttle if it becomes unbalanced.

[0052] Thus, by positioning the log loading compartment to ensure balance or stability of the shuttle, the logs in the log loading compartment can be maintained substantially level, and the reliability of the driving of the self-driving shuttle can be further improved. [0053] In some examples, the traction arrangement of the shuttle may have a mounting configured for displacement of individual elements of the traction arrangement, and the mounting may be configured to preserve contact between elements of the traction arrangement and a driving surface. Such a mounting may further improve the stability and reliability of driving of the shuttle.

[0054] The log loading compartment may be configured to be replaceably removed from the shuttle, for example by a crane arrangement or by action of some other removal arrangement comprised in the shuttle or separate therefrom. Such a removeable log loading compartment can be thought of as a ‘cassette’, which enables a shuttle to be loaded with logs, drive to an unloading location for depositing the logs, and deposit the entire loaded cassette at the unloading location.

[0055] An example operation of a self-driving log forwarder shuttle having log loading compartment configures as a cassette may be as follows. The shuttle, having an empty cassette navigates to a harvester that is felling trees and harvesting logs. The harvester may load logs directly onto the shuttle, into the log loading compartment (i.e. the cassette) until the cassette is deemed to be full (or at some determined capacity).

[0056] During loading of the shuttle, the shuttle and the harvester may be mutually coupled via respective electrical couplings such that the electrical energy storage can be charged by the electrical energy generator of the harvester - i.e. the harvester may serve as the mobile charging station in this way.

[0057] Once loaded with logs, the shuttle may navigate to an unloading location such as a side of a forestry base road, wherefrom logs can be loaded onto onward transportation such as boats, trucks or trains.

[0058] At the unloading location the shuttle may have the loaded cassette removed and left at the unloading location, and a new empty cassette replaced onto the shuttle such that the shuttle can promptly return again to the harvester for further logs.

[0059] Thus, by providing a self-driving log forwarder shuttle having a replaceably removable log loading compartment, the overall efficiency of the forestry operations may be improved. That is, harvester shuttles may not be required to wait excessively for logs to be removed therefrom, and the shuttles may return to the harvester as early as possible, thus increasing the availability of shuttles to the harvester. Therefore, there may be fewer shuttles required to carry out the forestry operations at the desired rate and efficiency.

[0060] The cassette may be removed from the shuttle by a crane arrangement such as a hook lift, a grapple or similar lifting crane configured for lifting a cassette from a shuttle and replacing a new empty cassette onto the shuttle to serve as the log loading compartment thereof.

[0061] In some examples, the crane arrangement may be a separate forestry machine, for example arranged at an unloading location where logs are expected to be unloaded from the shuttles (e.g. a side of a forestry road). [0062] Alternatively, the crane arrangement may be comprised in the shuttle. Thus, the shuttle may be configured with a crane arrangement, controlled by the controller of the shuttle, such that the shuttle can remove its own cassette and/or replace the cassette with an empty cassette. In this way, the shuttles may be advantageously self-sufficient and not be required to wait for an unloading crane to change out their cassette before they can return for further loading of logs, thus further improving the work efficiency of the forestry operations.

[0063] In some examples, the crane arrangement may be further configured to collect logs from the ground, or unload logs from the cassette/log loading compartment. Thus, if the harvester has placed logs on the ground in anticipation for the arrival of a shuttle, the shuttle may load said logs into the log loading compartment itself such that the harvester is not required to stop harvesting operations in order to load the logs into the shuttle’s log loading compartment.

[0064] According to some examples, the shuttle may be configured in such a way to track the motion of the mobile charging station whilst they are mutually coupled. That is, the controller of the shuttle may be further configured to control the driving of the shuttle to track a motion of the mobile charging station during the charging of the electrical energy storage of the shuttle, thereby maintaining said mutual coupling of the respective electrical couplings.

[0065] Therefore, the shuttle may not be dragged or pushed by a mechanical coupling, which can be difficult to engage or disengage, and can become damaged under load. Furthermore, the self- sufficiency of the shuttle is further enhanced.

[0066] Thus, as will be appreciated from the forgoing, viewed from these aspects, there is provided a forestry forwarder system having improved work efficiency and environmental impact.

[0067] Whilst the invention is susceptible to various modifications and alternative forms, specific embodiments are shown by way of example in the drawings as herein described in detail. It should be understood, however, that the detailed description herein and the drawings attached hereto are not intended to limit the invention to the particular form disclosed. Rather, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the appended claims.

[0068] Any reference to prior art documents or comparative examples in this specification is not to be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field.

[0069] As used in this specification, the words “comprise”, “comprising”, and similar words are not to be interpreted in the exclusive or exhaustive sense. In other words, they are intended to mean “including, but not limited to”.

BRIEF DESCRIPTION OF THE DRAWINGS

[0070] One or more embodiments will be described, by way of example only, and with reference to the following figures, in which: [0071] Figure 1 shows a side view of a self-driving log forwarder shuttle, according to an embodiment;

[0072] Figure 2 shows a perspective view of a self-driving forwarder shuttle having a log loading compartment that is positionable relative to the traction arrangement, according to an embodiment; [0073] Figure 3 shows a side view of a self-driving forwarder shuttle having a log loading compartment that is replaceably removeable and a crane arrangement, according to an embodiment; [0074] Figure 4 shows an overview of example forestry operations including self-driving log forwarder shuttles;

[0075] Figure 5 shows a side view of a harvester 10, acting as a mobile charging station, coupled to three shuttles 20, wherein the shuttles 20 are coupled together in a train configuration;

[0076] Figures 6A and 6B show a side and top view, respectively, of a double shuttle arrangement for a shuttle, according to an embodiment; and

[0077] Figure 7 schematically shows a self-driving log forwarder shuttle system according to an embodiment.

DETAILED DESCRIPTION

[0078] The present invention is described in the following by way of a number of illustrative examples. It will be appreciated that these examples are provided for illustration and explanation only and are not intended to be limiting on the scope of the present invention. Instead, the scope of the present invention is to be defined by the appended claims. Furthermore, although the examples may be presented in the form of individual embodiments, it will be recognised that the invention also covers combinations of the embodiments described herein.

[0079] Figure 1 shows a side view of a self-driving log forwarder shuttle 20, according to an embodiment.

[0080] As shown in figure 1, the shuttle 20 comprises a log loading compartment 21 for receiving harvested logs, a traction arrangement 22 powered by an electrical energy storage (not shown) and configured to drive the shuttle 20, and an electrical coupling 23 for coupling to a mobile charging station thereby enabling charging of the electrical energy storage of the shuttle 20 by the mobile charging station.

[0081] In the illustrated example, the shuttle 20 further comprises a removeable log loading compartment 21 and a crane arrangement 25 for removing the log loading compartment from a bed 29 of the shuttle 20. This operation is discussed in more detail below in relation to figure 3.

[0082] The shuttle 20 may further comprise a controller (not shown) connected to the traction arrangement 22 and configured to control the driving of the shuttle. The controller may be connected via a wired or wireless connection, and the controller may be situated in the body of the shuttle 20 or remote therefrom. [0083] The traction arrangement 22 in this illustrated example is a continuous track, which may further reduce the ground impact of the shuttle 20 by spreading its weight more evenly. However, in some examples, the traction arrangement 22 may take a different form, such as a set of wheels, e.g. 4, 6, 8 or more wheels.

[0084] The traction arrangement 22 of the shuttle 20 may be powered by an electrical energy storage (not shown) such as a battery, a capacitor bank, and/or some other energy storage system. The electrical energy storage may be accessibly comprised as part of the shuttle 20 and electrically connected to the powered components of the traction arrangement 22.

[0085] The electrical energy storage is electrically connected to the electrical coupling 23 of the shuttle 20, and this electrical coupling 23 is used to enable charging of the electrical energy storage, i.e. from a mobile charging station.

[0086] In some examples, the traction arrangement 22 may be configured for regenerative charging of the electrical energy storage, such that a braking action or downhill travel of the traction arrangement 22 can be used to generate electrical energy for replenishing the charge of the electrical energy storage.

[0087] The position of the electrical coupling 23 may be configured for interfacing with the mobile charging unit under the shuttle’s 20 own action. That is, the electrical coupling 23 may be positioned such that the shuttle 20 can drive in a self-driving manner to the mobile charging station and couple with an electrical coupling thereof without requiring a human intervention to mutually couple the electrical couplings of the shuttle 20 and the mobile charging station.

[0088] The log loading compartment 21 is illustrated as comprising a series of upstanding arms proximate to an end plate, arranged to define a holding area, and a plurality of logs are shown held by the arms in the log loading compartment 21. In the illustrated example, the log loading compartment 21 is open-ended at one side and is shown as being substantially full. In some examples, the log loading compartment may have end plates at both ends or neither, and the fill level of the log loading compartment 21 may be dynamically altered according to a work efficiency requirement, an environmental assessment, and/or other static or changeable factors.

[0089] The log loading compartment 21 may be arranged on a bed 29 of the shuttle 20, which may be substantially level with an upper portion of the traction arrangement 22, or above or below, or at a changeable position (i.e. by configuring the bed 29 to be positionable), depending on the desired balance properties of the shuttle 20.

[0090] The motion of the bed 29 may further cause a motion of the electrical coupling 23, thus allowing a dynamic positioning of the electrical coupling 23 to facilitate an ease of mutual coupling between the electrical couplings of the shuttle 20 and the mobile charging station by placing them at a same relative height or position. [0091] For example, it may be desired to give the shuttle 20 a low centre of gravity. Thus, after decoupling the electrical coupling 23 from the mobile charging station, the bed 29 may be lowered to move the centre of gravity of the shuttle 20 lower and thus improve the stability of the shuttle 20. [0092] Figure 2 shows a perspective view of the shuttle 20 where the log loading compartment 21 has been positioned out of alignment with the traction arrangement 22.

[0093] The log loading compartment 21 may be positionable relative to the traction arrangement 22 by action of one or more positioning means (not shown) such as pistons, tracks, rail, and/or any other means suitable for positioning the log loading compartment 21 (e.g. when full of logs) along a vertical, horizontal, and/or rotational axis.

[0094] The log loading compartment 21 may for example be slideably mounted on the bed 29 so as to allow a transfer of the log loading compartment 21 to a bed 29 of a neighbouring shuttle 20. As illustrated in figure 2, the log loading compartment 21 may be rotatable relative to the traction arrangement 22, which may allow for an increased ease of loading/unloading logs therein/therefrom, thus improving the work efficiency of the loading and unloading operations. The desired positioning of the log loading compartment 21 may further be determined based on a required balance or centre of gravity of the shuttle 20.

[0095] In some examples, the mobile charging station may instruct the positioning of the log loading compartment 21 (i.e., via the controller of the shuttle 20) so as to enable an ease of coupling the electrical coupling 23 with the mobile charging station.

[0096] In some further examples, a harvester (or some equivalent forestry machine) may communicate a position of its processing head when loading logs into the log loading compartment 21, such that the log loading compartment 21 may be automatically positioned, i.e. rotated, so as to align the axis of the log loading compartment 21 with the axis of the incoming log. As an alternative to having such information communicated to the shuttle 20, the shuttle 20 may instead rely on one or more on board sensors for detecting an incoming log.

[0097] Figure 3 shows a side view of a shuttle 20 removing its own log loading compartment 21 via an onboard crane arrangement 25, according to an embodiment.

[0098] The shuttle 20 may be substantially the same or similar to the shuttle 20 described in relation to figures 1 and 2, and like-numbered components may have substantially the same or similar functions as those previously described, and thus these descriptions are not repeated for the sake of conciseness.

[0099] As is illustrated in figure 3, the shuttle 20 may comprise a crane arrangement 25 for replaceably removing the log loading compartment 21 from the shuttle 20. In the following discussion, the replaceably removeable log loading compartment 21 may also be referred to as a cassette 21. [0100] Although the crane arrangement 25 is shown as being a piston and a pivoting arm rotatably coupled to the end plate of the log loading compartment 21, it will be appreciated that the crane arrangement 25 may take any suitable form. Indeed, the crane arrangement 25 may not comprise any component that is a crane or crane-like.

[0101] For example, the cassette 21 may be removed from the shuttle 20 by action of an inclining motion of the bed 29, which may cause the cassette 21 to detach and/or slide off of the bed 29 and off of the shuttle 20.

[0102] In another example, the crane arrangement 25 may comprise a dangling head that engages (i.e. hooks, grapples, magnetically attaches, etc.) an upper portion of the cassette 21 so as to lift the cassette 21 off of the shuttle 20, and thereafter move the cassette 21 to a position on the ground, another shuttle 20, or some other unloading location.

[0103] It will be appreciated that, irrespective of the means by which the crane arrangement 25 (which may be thought of generally as an unloading arrangement) removes the cassette 21, the cassette 21 being replaceable removeable may provide a number of advantages, which will become apparent when considered in the context of the forestry operations performed.

[0104] Figure 4 shown an overview of forestry operations, containing the system 1 and involving a plurality of self-driving log forwarder shuttles 20 and a mobile charging station 10, according to an embodiment.

[0105] In this particular example, the mobile charging station 10 is a harvester forestry machine, although it will be appreciated that the mobile charging station 10 may take any form suitable for performing the functions described for it herein.

[0106] The shuttles 20 may have one or more of the components as described for the shuttles 20 in any of figures 1 to 3, or greater or fewer components, depending on the implementation.

[0107] The system 1 may further comprise an unloading crane 40 at an unloading location for unloading logs from the shuttles 20 and/or cassettes 21 from the shuttles 20.

[0108] The forestry site may comprise one or more driving paths 80a, 80b (which may be collectively referred to as driving paths 80) through the forestry site, along which the shuttles 20, the harvester 10, and/or the unloading crane 40 may drive during the course of forestry operations.

[0109] The driving paths 80 may be predetermined according to monitoring information that has been gathered about the forestry site (e.g. by one or more UAVs collecting information about the forestry site). Alternatively, the driving paths 80 may be dynamically determined by the shuttles 20, UAVs, the mobile charging station 10 and/or some combination thereof.

[0110] For example, the shuttles 20 may comprise one or more navigation sensors 27 connected to the controller thereof (e.g. one controller for each shuttle 20 or one controller for many/all shuttles 20). Then, the controller may be configured to control the driving of the shuttle 20 based on the collected information from the one or more navigation sensors 27, such as object detection information (detecting the location of trees or obstacles etc.), GNSS information (e.g. a location of the mobile charging station 10 and/or unloading crane 40) and/or some other information suitable for informing the determination of the driving paths 80 through the forestry site.

[OHl] As shown in figure 4, one shuttle 20 is coupled to a harvester 10, acting as a mobile charging station. The harvester 10 has an articulated boom with a processing head attached thereto, and the harvester 10 is loading a log onto the log loading compartment 21 of a coupled shuttle 20. Thus, the shuttle 20 is being charged by the harvester 10 at a same time as having a log loaded thereon by the harvester 10.

[0112] As can be seen in figure 4, there is a loaded shuttle 20 returning to the unloading location via driving path 80a and an unloaded shuttle 20 navigating to the harvester 10 via driving path 80b. In some examples, the shuttles 20 may use a same driving path 80, and in other examples, the shuttles 20 may be load balanced along different driving paths 80 so as to prevent congestion of driving paths 80 and/or excessive ground impact on the driving paths 80.

[0113] Three shuttles 20 can be seen at the unloading location. From left to right, the first can be seen having logs being loaded therefrom by the unloading crane 40. This shuttle 20 may not have a cassette but may instead have a fixed log loading compartment 21. The second shuttle 20 can be seen unloading its full cassette 21 onto a ground position, which may be predetermined and assigned to it by a wider forestry monitoring system, the unloading crane 40, the harvester 10, or determined dynamically by the shuttle 20 itself, e.g. according to an assessment by one or more onboard sensors. [0114] The third (right-most) shuttle 20 can be seen collecting an empty cassette 21, for example after it has deposited its full cassette 21 at the unloading location, after which the unloading crane 40 may remove and/or sort the logs therefrom without requiring the shuttle 20 to wait for this operation to be completed. Once the shuttle 20 has unloaded its full cassette 21 and loaded a new empty cassette 21, the shuttle 20 may immediately return to the harvester 10 for a further load of logs. Thus, the work efficiency of the forestry operations may be increased.

[0115] By charging the shuttles 20 using the harvester 10, it can be seen that they may only require an electrical energy storage that is sized for a round trip from the harvester 10 to the unloading location, and back again. There may be some margin of error included in a calculation of a minimum size for the electrical energy storage. Furthermore, the unloading crane 40 may act as a further mobile charging station 10 such that the shuttles 20 can be charged during unloading as well. In such examples, the size of the electrical energy storage of the shuttles 20 may be further reduced.

[0116] By not requiring the electrical energy storage to be sized to accommodate for an entire working operation length, e.g. a whole working day, the electrical energy storage of the shuttles 20 may have an optimised (i.e. minimised) size. A reduced size of electrical energy storage may have a reduced weight. Therefore, the overall weight of the shuttles 20, as a result of the described system 1 having a mobile charging station 10 for charging the shuttles 20 during operations, may be reduced. Hence, the ground impact of the shuttles 20 on the driving paths 80 can be reduced, which improves the overall environmental impact of the forestry operations. Moreover, the use of electric shuttles 20 may reduce the emissions from shuttles 20, which may further improve the environmental impact of the forestry operations.

[0117] The mobile charging station 10 has a fuel reservoir fuelling an electrical energy generator, for example one based on an internal combustion engine. The engine may be configured to run at an optimal RPM for running the electrical energy generator so as to optimise the energy efficiency of the system 1.

[0118] Figure 5 shows a side view of a harvester 10, acting as a mobile charging station, coupled to three shuttles 20, wherein the shuttles 20 are coupled together in a train configuration.

[0119] The harvester 10 may be configured to be able to charge a plurality of interconnected shuttles 20, where one of the shuttles 20 may be connected to the harvester 10 via the electrical coupling 23. By being able to charge more than one shuttle 20, the harvester 10 allows for transport of shuttles 20 between, for example, work sites and may be able to charge the shuttles 20 during the transport. Thus, the operation of the harvester 10 and the shuttles 10 may begin as soon as the harvester 10 has reached the work site.

[0120] Further, by being able to charge more than one shuttle 20, the harvester 10 enables charging during downtime of the operation of the harvester 10, such as during the night. Thus, once operation of the harvester 10 starts the shuttles 20 may be ready for deployment. The harvester 10 is not limited to being coupled to one, two, or three shuttles 20, and may be coupled to substantially any number of shuttles 20.

[0121] The coupled shuttles 20 may also be configured to exchange electrical energy between each other. For example, the controller 26 of the shuttles 20 may be configured to monitor an electrical energy level of their respective energy storages 24 and communicate directly or indirectly (e.g. via the harvester 10) to request charging or advertise capacity for providing charging.

[0122] The connection between the shuttles 20 and the harvester 10 and between different shuttles 20 may be mechanical, e.g. via some form of clip, clamp, hook, or similar arrangement. Additionally or alternatively, the controller 26 of the shuttles 20 may be configured to track a motion of the harvester 10 and/or the other shuttles 20.

[0123] The motion of coupled machinery may be directly monitored, e.g. via sensors, or transmitted to the controller of the shuttles 20. For example, the harvester 10 may communicate its driving control intention to the shuttle(s) 20 such that their respective controllers 26 control their driving based thereon. The intention of such tracking is to preserve an electrical connection between the shuttles 20 and/or between the shuttle 20 and the harvester 10.

[0124] In some examples, a plurality of shuttles 20 may be configured in a permanently coupled state. That is, as shown in figures 6A and 6B, a shuttle 20 may be comprised of two sub-shuttles having a flexible connection 201 therebetween, similarly as having two constantly connected shuttles, having mechanical connecting means joining therebetween. Such an arrangement may be referred to as a ‘double shuttle 20’.

[0125] The sub-shuttles may be connected in an articulated manner applying hydraulic cylinders 202 or other steering means that may cause pivoting around a vertical hinge 201. Additionally, the subshuttles may be able to rotate relative to each other along a longitudinal axis 203 of the shuttle 20. Such relative rotation may be limited to a suitable amount, for example 10-20 degrees.

[0126] The flexible/articulatable connection 201 may be any suitable mechanical connection for joining the sub-shuttles together to form the double shuttle 20. For example, a hinge, a ball joint, a clevis, or the like.

[0127] The steering means 202 may take any suitable form for causing a turning or steering of the double shuttle 20 by articulation about the connection 201. The steering means may be controlled by a controller of the shuttle 20.

[0128] By configuring a shuttle 20 in such a way, the ground impact of a shuttle 20 may be further reduced, as the surface area can be effectively doubled - see figure 6A showing two sets of continuous tracks, for example. Another way of considering such an arrangement would be that the traction arrangement of the double shuttle has two axles. As a consequence, the overall reduction of weight of the shuttle unit (e.g. by removing fuel, driver cab, etc.) is enhanced, and in combination with an effectively doubled surface area, the ground impact may be substantially improved.

[0129] The longer wheelbase of such a double shuttle 20 arrangement may further improve the capability of a shuttle 20 to drive across steep or otherwise uneven terrain.

[0130] Figure 7 shows a schematic diagram of a self-driving log forwarder shuttle system, comprising a self-driving log forwarder shuttle 20 and a mobile charging station 10, according to an embodiment.

[0131] The shuttle 20 may comprise an electrical energy storage 24 connected to a traction arrangement 22 which is powered thereby. The traction arrangement 22 may be controlled by a controller 26 that is connected thereto, e.g. by wired or wireless means.

[0132] In some examples, the shuttle 20 may further comprise an energy monitor 28 connected to the controller 26 for monitoring the charge level of the electrical energy storage 24. This information may be used to ensure that the shuttle 20 does not run out of charge during operations, and the controller 26 may instruct the shuttle 20 to charge at the mobile charging station 10 for a length of time (or to an energy level threshold) sufficient for the shuttle 20 to continue its operations uninterrupted by power shortages.

[0133] Such a threshold may be static or dynamic and may be determined locally or remotely from the shuttle 20, for example using an application of Al or ML techniques. The controller 26 may be further configured to calculate a travel time from a first location to a second location (e.g. from a log loading location to a log unloading location and/or vice versa), which may further factor into calculations of a threshold or length of time required for charging at the mobile charging station 10. [0134] As previously discussed, the shuttle 20 may further comprise one or more navigation sensors 27 connected to the controller 26 (e.g. via wired or wireless means), the navigation sensors 27 being configured to collect information about the driving environment around the shuttle 20. The sensors 27 may include distancing sensors such as a stereo camera arrangement or LIDAR, a temperature sensor such as an infrared camera, and/or some other sensors suitable for collecting information about the forestry environment and informing navigation decisions for the shuttle 20.

[0135] By using onboard sensors, the shuttle 20 may advantageously not be required to maintain a data connection to external devices which may otherwise be making driving path decisions for the shuttle 20.

[0136] In some examples, as previously described, the shuttle may further comprise a crane arrangement 25 or some other arrangement suitable for removing a cassette-style log loading compartment 21 and/or moving logs to or from the log loading compartment 21 of the shuttle 20. [0137] The shuttle 20 and the mobile charging station 10 each comprise respective electrical couplings 23. The mobile charging station 10 comprises a fuel reservoir 12 which fuels an electrical energy generator 13. Thus, when the electrical couplings 23 are mutually coupled 23 to each other, the electrical energy storage 24 of the shuttle 10 can be charged by the electrical energy generator 13 of the mobile charging station 10.

[0138] The mobile charging station 10 is navigable via an operation of a traction arrangement 11 comprised therein. Thus, the mobile charging station 10 can be navigated through a forestry site during forestry operations to charge shuttles 20 whilst they conduct forestry operations, as previously described.

[0139] The electrical couplings 23 may take any suitable form. For example, the electrical couplings 13 may comprise a male and female coupling for reliably mating and engaging during charging. Alternatively, the couplings 23 may comprise a substantially similar shape and construction, for example, the couplings 23 may be configured to electrically connect upon abutment thereof, thus allowing an ease of electrical connection without perfect alignment of the couplings 23. It will be appreciated that the shuttle 20 and/or the mobile charging station 10 may comprise multiple electrical couplings 23 to enable a simultaneous charging of multiple shuttles 20, for example with multiple shuttles 20 individually coupled to the mobile charging station 10 or coupled via another shuttle 20 as part of a train, as previously described.

[0140] In any event, it will be appreciated that the couplings 23 and other components can take a variety of forms whilst preserving the advantages achieved by the described system. It is not intended for the scope of protection to be defined by the specific examples of the figures. Instead, the scope of protection is defined by the appended claims.