An autonomous industrial transportation system

Abstract

An autonomous industrial transportation system comprising a modular track system (S) comprising a plurality of track tile modules (1) arranged in connection to each other for providing a driving track structure (2). The autonomous industrial transportation system further comprises a plurality of self-driving wheeled transport vehicles (V) arranged on the driving track structure (2) and having an electric propulsion system and an electric energy storage (14), wherein the driving track structure (2) is configured for guiding wheels (W) of the transport vehicles (V). The autonomous industrial transportation system further comprises a plurality of shared charging stations (C1, C2) arranged for enabling charging of the electric energy storage (14) of the transport vehicles (V), wherein the total number of shared charging stations (C1, C2) is less than the total number of transport vehicles (V), and wherein all of said transport vehicles (V) have access to and can be charged by any of said shared charging stations (C1, C2). The autonomous industrial transportation system further comprises a control system (17) in communication with the plurality of transport vehicles (V), wherein the control system (17) is configured to control the transport vehicles (V) to maintain a target number (N2) of the transport vehicles (V) in charging state at the charging stations (C1, C2) during operation of the autonomous industrial transportation system.

Description

[0001] AN AUTONOMOUS INDUSTRIAL TRANSPORTATION SYSTEM

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to an autonomous industrial transportation system, and a method for controlling charging of plurality of self-driving wheeled transport vehicles of an autonomous industrial transportation system .

[0004] The autonomous industrial transportation system comprises a modular track system comprising a plurality of track tile modules, a plurality of self-driving wheeled transport vehicles, and a plurality of shared charging stations. The self-driving wheeled transport vehicles are also known as Autonomous mobile robots (AMR’s).

[0005] BACKGROUND

[0006] Transportation systems with self-driving wheeled transport vehicles are commonly used in different applications where there is a need for transporting objects or other goods between different transporting destinations. Such systems may for example be used in manufacturing facilities for transporting parts or products between workstations, and for transporting products to and from packaging stations. Other application areas may for example be in warehouses fortransporting goods or objects to different storage locations. The autonomous mobile robots are commonly arranged as driverless self-propelled transport vehicles providing automated material flows. Such driverless transport vehicles are generally guided by track systems, inductive conductors, or optical markings on the floor. However, freely navigating transport vehicles can also be used, where the vehicles are equipped with navigation devices for orientation on a transport surface.

[0007] T rack based transportation systems are used for an efficient guiding of the self-driving wheeled transport vehicles. However, current transportation systems are often complex in design and non-flexible in construction.

[0008] In addition, the charging process for charging the electrical battery of each transport vehicle requires not only a significant space for the charging stations, in particular when the autonomous industrial transportation system includes a large number of individual transport vehicles, but also a high investment cost for the acquisition and installation of the charging stations.

[0009] There is thus a need for an improved autonomous industrial transportation system that provides a robust, flexible and reliable modular track system, in combination with a more flexible and cost-efficient charging process.

[0010] SUMMARY

[0011] An object of the present disclosure is to provide an autonomous industrial transportation system where the previously mentioned problems are avoided. This object is at least partly achieved by the features of the independent claims.

[0012] According to a first aspect of the present disclosure, there is provided an autonomous industrial transportation system.

[0013] Preferably, the autonomous industrial transportation system comprises a modular track system, preferably comprising a plurality of track tile modules arranged in connection to each other for providing a driving track structure.

[0014] Preferably, the autonomous industrial transportation system comprises a plurality of self-driving wheeled transport vehicles arranged on the driving track structure and having an electric propulsion system and an electric energy storage.

[0015] Preferably, the driving track structure is configured for guiding wheels of the transport vehicles.

[0016] Preferably, the autonomous industrial transportation system comprises a plurality of shared charging stations arranged for enabling charging of the electric energy storage of the transport vehicles.

[0017] Preferably, the total number of shared charging stations is less than the total number of transport vehicles.

[0018] Preferably, all of said transport vehicles have access to and can be charged by any of said shared charging stations. Preferably, the autonomous industrial transportation system comprises a control system in communication with the plurality of transport vehicles.

[0019] Preferably, the control system is configured to control the transport vehicles to maintain a target number N2 of the transport vehicles in charging state at the charging stations during operation of the autonomous industrial transportation system.

[0020] In this way, the track tile modules with the driving track structure provide a robust, flexible and reliable modular track system, and the new charging strategy having a target number of transport vehicles in charging state enables significantly reduced number of charging stations, such that a more flexible and cost-efficient autonomous industrial transportation system is provided.

[0021] Further advantages are achieved by implementing one or several of the features of the dependent claims.

[0022] In some example embodiments, that may be combined with any one or more of the above-described embodiments, a minimum number of shared charging stations is not less than the target number N2.

[0023] In some example embodiments, that may be combined with any one or more of the above-described embodiments, the control system is configured to determine the target number N2 based on: a charging power of each of the plurality of shared charging stations and collective power consumption of all operational transport vehicles; and / or a collective charging state of all transport vehicles or of all operational transport vehicles (V).

[0024] In some example embodiments, that may be combined with any one or more of the above-described embodiments, the target number N2 is less than 30%, specifically less than 20%, of the total number of transport vehicles or of all operational transport vehicles (V).

[0025] In some example embodiments, that may be combined with any one or more of the above-described embodiments, the target number N2 is an integer value within a

[0026] P vehicle x N'l range determined by equation N2 = — - x C, wherein P_vehicle is electrical

[0027] P_charger power level of each self-driving wheeled transport vehicle; N1 is total number of operational transport vehicles; P_charger is the electrical charging power level of each individual charging station; and C is a constant in the range of 0.5 -2, specifically in the range of 1.0 - 1.5.

[0028] In some example embodiments, that may be combined with any one or more of the above-described embodiments, the control system is configured to prioritize keeping the target number N2 of transport vehicles in charging state at the charging stations during operation of the autonomous industrial transportation system, over processing of incoming / pending transport assignments.

[0029] In some example embodiments, that may be combined with any one or more of the above-described embodiments, the control system is configured to select next transport vehicle to be charged at any of the charging stations based on one or more of the following parameters: state of charge of the electric energy storage of the transport vehicles; remaining operating time of the transport vehicles; remaining driving length of the transport vehicles; location of the transport vehicles; driving length of the transport vehicles to a charging station; driving time of the transport vehicles to a charging station; transport vehicle charging urgency level.

[0030] In some example embodiments, that may be combined with any one or more of the above-described embodiments, the control system is configured to control the transport vehicles, such that the transport vehicle selected to be charged next, will be assigned to drive to the nearest available charging station

[0031] In some example embodiments, that may be combined with any one or more of the above-described embodiments, the control system is configured to initiate change of transport vehicle, at a charging station, based on one or more of the following events and / or parameters: when the currently charged vehicle at the charging station has a state of charge at or above a predetermined level; when the transport vehicle to be charged next has a state of charge below a predetermined level; when remaining operating time of the transport vehicle to be charged next is below a predetermined level; when remaining driving length of the transport vehicle to be charged next is below a predetermined level; when charging urgency index of the transport vehicle to be charged next is above a predetermined level; when a predetermined number or percentage of all transport vehicles has a state of charge or remaining operating time or remaining driving length below a predetermined charge level or a charging urgency level above a predetermined level. In some example embodiments, that may be combined with any one or more of the above-described embodiments, the control system is configured to, after a change of transport vehicle at a certain charging station has been initiated, control the transport vehicle currently located at the charging station to depart from the charging station based on: the position of the transport vehicle to be charged next; or the remaining driving length of the transport vehicle to be charged next to an available charging station; or the remaining driving time of the transport vehicle to be charged next to an available charging station.

[0032] In some example embodiments, that may be combined with any one or more of the above-described embodiments, each of the shared charging stations include a charging connector, and wherein each of the transport vehicles include corresponding charging connector that is adapted to be connected to the charging connector of the charging station for enabling charging of the electric energy storage of the transport vehicle.

[0033] In some example embodiments, that may be combined with any one or more of the above-described embodiments, the control system is configured for assigning the task of driving to a charging station in a state when the transport vehicle is not carrying any cargo.

[0034] In some example embodiments, that may be combined with any one or more of the above-described embodiments, some or all of the charging stations are located: in region of the transport route network where the transport vehicles normally do not carry any cargo, and / or in region of the transport route network that corresponds to a high traffic region.

[0035] In some example embodiments, that may be combined with any one or more of the above-described embodiments, a total number of charging stations is less than 50%, specifically less than 30%, of a total number of transport vehicles.

[0036] In some example embodiments, that may be combined with any one or more of the above-described embodiments, each of the charging stations is rigidly attached to a track tile module, or the autonomous industrial transportation system comprises one or more dedicated charging track tile modules that are different from the track tile modules that are forming the driving track, and wherein each of the charging stations are located on, and fastened to, a charging track tile module. The disclosure also relates to a method for controlling charging of plurality of selfdriving wheeled transport vehicles of an autonomous industrial transportation system.

[0037] Preferably, the autonomous industrial transportation system comprises a modular track system comprising a plurality of track tile modules arranged in connection to each other for providing a driving track structure.

[0038] Preferably, the driving track structure is configured for guiding wheels of the transport vehicles.

[0039] Preferably, the method comprises controlling the transport vehicles to maintain a target number N2 of the transport vehicles in charging state at the charging stations during operation of the autonomous industrial transportation system.

[0040] Further features and advantages of the invention will become apparent when studying the appended claims and the following description. The skilled person in the art realizes that different features of the present disclosure may be combined to create embodiments other than those explicitly described hereinabove and below, without departing from the scope of the present disclosure.

[0041] BRIEF DESCRIPTION OF DRAWINGS

[0042] The autonomous industrial transportation system according to the disclosure will be described in detail in the following, with reference to the attached drawings, in which

[0043] Fig. 1a-1b show schematically a modular track system comprising a plurality of track tile modules and a transport vehicle,

[0044] Fig. 2a-2b show schematically upper and lower side of a track tile module,

[0045] Fig. 3a-3b show schematically a side view and top view of a transport vehicle having turning wheels,

[0046] Fig. 4a-4b show schematically a side view and top view of a transport vehicle having lifting wheels,

[0047] Fig. 5a-5c show schematically a sequence of the transport vehicle entering a charging state,

[0048] Fig. 6 shows schematically a modular track system having a plurality of transport vehicles and a plurality of charging stations, Fig. 7 shows schematically an example of a charging profile according to the present disclosure,

[0049] Fig. 8 shows schematically an example of prior art charging profile,

[0050] Fig. 9 shows schematically a layout of the control system together with associated parts,

[0051] Fig.10 shows schematically a layout of the control system

[0052] Fig.11 shows an example embodiment of a vehicle control system,

[0053] Fig. 12-15 show flowcharts describing various example methods for operating the control system of the industrial transportation system and vehicles.

[0054] DESCRIPTION OF EXAMPLE EMBODIMENTS

[0055] Various aspects of the disclosure will hereinafter be described in conjunction with the appended drawings to illustrate and not to limit the disclosure, wherein like designations denote like elements, and variations of the described aspects are not restricted to the specifically shown embodiments, but are applicable on other variations of the disclosure.

[0056] With reference to figure 1a and 1b, the disclosure relates to an autonomous industrial transportation system comprising a modular track system S comprising a plurality of track tile modules 1 arranged in connection to each other for providing a driving track structure 2, and at least one self-driving wheeled transport vehicle V arranged on the track tile modules 1 , wherein the driving track structure 2 is configured for guiding wheels of the at least one transport vehicle V.

[0057] Figure 1a schematically shows a perspective view of the of a modular track system S, and figure 1b shows a more detailed top view of a modular track system S. The modular track system S comprises a plurality of track tile modules 1 arranged in connection to each other. By arranging the track tile modules 1 in connection to each other, a driving track structure 2 configured for guiding wheels of a self-driving wheeled transport vehicle V is provided. The transport vehicle V is used for transporting any suitable type of object or objects between different locations of the modular track system S, such as for example between different workstations or from a workstation to a packing unit or other transportation unit. The track tile modules 1 may be installed on almost any type of rigid base structure. For example, the track tile modules 1 may be installed directly on a relatively flat ground or floor, or on an underlying base structure comprising support beams or the like. The track tile modules 1 are arranged in connection to each other and preferably attached to the base structure.

[0058] The configuration of the driving track structure 2 is enabling transportation of the transport vehicle V in a longitudinal direction DLO of the modular track system S, and in a lateral direction DLA of the modular track system S. By designing the transport vehicle V with wheels that are rotatably arranged, the transport vehicle V can alter between driving in the longitudinal direction DLO and the lateral direction DLA of the modular track system S.

[0059] The transport vehicle V may be connected to a control unit for controlling the driving operation. Alternatively or in combination, the transport vehicle V is provided with a suitable software for controlling the driving operation. It should be understood that the autonomous industrial transportation system according to the present disclosure is configured for having a plurality of transport vehicles V operated simultaneously on the modular track system, each working on completing its own individual transportation task.

[0060] The track tile modules comprise a driving track structure 2 having a grooved driving track structure 2 or a protruding driving track structure 2.

[0061] When the driving track structure 2 is provided with a grooved driving track structure 2, the grooved driving track structure 2 comprises a first pair of parallel track grooves 2a and a second pair of parallel track grooves 2b extending in a direction perpendicular to the first pair of parallel track grooves 2a in an intersecting relationship, wherein the grooved driving track structure is formed integrally in or attached to the plurality of track tile modules and configured to guide the wheels of the transport vehicle.

[0062] The grooved track structure 2 of the track tile modules 1 are forming the driving track structure 2 when the track tile modules 1 are arranged in connection to each other.

[0063] When the driving track structure 2 is provided with a protruding driving track structure 2, the protruding driving track structure 2 comprising a first pair of parallel track protrusions 2a and a second pair of parallel track protrusions 2b extending in a direction perpendicular to the first pair of parallel track protrusions 2a in an intersecting relationship, wherein the protruding driving track structure is formed integrally in or attached to the plurality of track tile modules and configured to guide the wheels of the transport vehicle. The protruding driving track structure is for example a rail structure or the like.

[0064] As indicated in figures 1a-b, the first pair of parallel track grooves 2a of the track tile modules 1 when arranged in connection to each other define first drive lanes Di for the transport vehicle V. The first drive lanes Di are configured to guide the wheels W of the transport vehicle V in the longitudinal direction DLO along first pairs of parallel track grooves 2a of track tile modules 1 arranged in connection to each other. The second pair of parallel track grooves 2b of the track tile modules 1 when arranged in connection to each other define second drive lanes D2 for the transport vehicle V. The second drive lanes D2 are configured to guide wheels W of the transport vehicle V in the lateral direction DLA along second pairs of parallel track grooves 2b of track tile modules 1 arranged in connection to each other. The arrangement with the first drive lanes Di and the second drive lanes D2 is enabling different possibilities for routing the transport vehicle V, and the drive lanes may be arranged in many different ways, depending on how the track tile modules 1 are arranged in connection to each other.

[0065] The modular track system S comprises a plurality of track tile modules 1 attached to the base structure. In the embodiment shown in figures 1a-b, the plurality of track tile modules 1 attached to the base structure are configured as tile modules having the same design, i.e. they are identical and / or manufactured by the same manufacturing tool, such as the same injection moulding tool.

[0066] With reference to figures 1a - 2a, the base structure 3 may be configured as a floor structure, or as a frame or beam system arranged for holding the plurality of track tile modules 1. The track tile modules 1 may be configured as single piece track tile modules, or the track tile modules 1 may be configured as multi-piece track tile modules comprising two or more joined track tile sub-parts 1a.

[0067] The track tile module 1 is, as described above, providing a driving track structure 2 for the self-driving wheeled transport vehicle V. As illustrated in figures 2a-b, the track tile module 1 comprises an upper side 5a intended to face upwards and a lower side 5b intended to face downwards towards the base structure 3. The grooved track structure 2 is arranged on the upper side 5a, with the first pair of parallel track grooves 2a and the second pair of parallel track grooves 2b. The second pair of parallel track grooves 2b is extending in a direction perpendicular to the first pair of parallel track grooves 2a in an intersecting relationship. The grooved track structure 2 of the track tile modules 1 are forming the driving track structure 2 with the first drive lanes Di and the second drive lanes D2 when the track tile modules 1 are arranged in connection to each other.

[0068] As illustrated in figure 2a, the track tile modules 1 have an extension in a longitudinal direction DLO and a lateral direction DLA. The longitudinal direction DLO of the track tile modules 1 when the track tile modules 1 are arranged in connection to other track tile modules 1 in the modular track system S is corresponding to the longitudinal direction DLO of the modular track system S. The lateral direction DLA of the track tile modules 1 when the track tile modules 1 are arranged in connection to other track tile modules 1 in the modular track system S is corresponding to the lateral direction DLA of the modular track system S.

[0069] Intersections I of the first pair of parallel track grooves 2a with the second pair of parallel track grooves 2b form four track groove junctions J, as shown in for example figure 2a. When wheels W of the transport vehicle V are positioned in the track groove junctions J, the transport vehicle V can change driving directions between directions along the first pair of parallel track grooves 2a in the longitudinal direction DLO of the modular track system S and the second pair of parallel track grooves 2a in the lateral direction DLA of the modular track system S.

[0070] The track tile modules 1 comprise a first longitudinal side edge 6a, a second longitudinal side edge 6b, a first lateral side edge 7a, and a second lateral side edge 7b. The first pair of parallel track grooves 2a are extending in the longitudinal direction DLO of the track tile module 1 parallel to the first longitudinal side edge 6a and the second longitudinal side edge 6b. The second pair of parallel track grooves 2b are extending in the lateral direction DLA of the track tile module 1 parallel to the first lateral side edge 7a and the second lateral side edge 7b.

[0071] As a result, the second pair of parallel tracks 2b extend in a direction perpendicular to the first pair of parallel tracks 2a in an intersecting relationship. The lower side 5b comprises a plurality of integrated reinforcing ribs 12 that are enabling a stiff and durable construction of the track tile modules 1.

[0072] In the embodiment shown in figures 2a-b, the extension of the track tile modules 1 in the longitudinal direction DLO is greater than the extension of the track tile modules 1 in the lateral direction DLA. This different extension in the two directions is enabling a flexible and efficient system, where transport vehicles V of different configurations may be used. Further, the modular track system S could with this configuration of the track tile modules 1 be made efficient with respect to space needed for the system. As described above, the first pair of parallel track grooves 2a is arranged with a first track gauge G1 and the second pair of parallel track grooves 2b is arranged with a second track gauge G2, enabling formation of the driving track structure 2 when the track tile modules 1 are arranged in connection to each other. The second track gauge G2 is wider than the first track gauge G1 , as understood from for example figure 2a. The respective track gauges are adapted to the configuration of the transport vehicles and are matching distances between the wheels W of the transport vehicles V.

[0073] The track tile modules 1 comprise one or more locking arrangements 9 configured for releasably attaching the track tile modules 1 to the base structure 3. In the embodiments shown in figures 2a-b, the track tile modules 1 comprise four locking arrangements 9 arranged in each corner section of the track tile modules 1 .

[0074] The track tile module 1 also comprise alignment projections 8a and alignment recesses 8b, such that track tile modules 1 arranged next to each other are properly mutually aligned.

[0075] The transport vehicle V may have any suitable configuration, and to shift between driving in the first drive lanes Di and the second drive lanes D2, the transport vehicle V is arranged with wheels W that are rotatably arranged around a wheel axis Aw, as shown in figures 3a-b. In a first wheel position P1 , the transport vehicle V is configured for driving in the first drive lanes Di along first pairs of parallel track grooves 2a of track tile modules 1 arranged in connection to each other. In a second wheel position P2, where the wheels are rotated 90 degrees from the first position P1 , the transport vehicle V is configured for driving in the second drive lanes D2 along second pairs of parallel track grooves 2b of track tile modules 1 arranged in connection to each other. The wheels W are rotated between the first position P1 and the second position P2, when the transport vehicle is positioned on a track tile module 1 with each wheel W arranged in a corresponding track groove junction J of the track tile module 1 , such as the positions schematically shown in figures 1b and 3b. The transport vehicle V and / or the track tile modules 1 may be arranged with sensors or other suitable sensing devices for a correct positioning of the transport vehicle V on the track tile module 1 , aligning each wheel Wwith a corresponding track groove junction J.

[0076] In a first example, the transport vehicle V is driving in the longitudinal direction DLO along a first pair of parallel track grooves 2a with the wheels arranged in the first wheel position P1. To change driving direction of the transport vehicle V from driving in the longitudinal direction DLO along the first pair of parallel track grooves 2a to driving in the lateral direction DLA along a second pair of parallel track grooves 2b, the transport vehicle V is propelled in the longitudinal direction DLO and stopped at any track tile module 1 of the modular track system S suitable for changing driving direction. When the transport vehicle V is positioned on the track tile module 1 with each wheel W arranged in a corresponding track groove junction J of the track tile module 1 , as shown in figure 3b, the wheels are rotated from the first wheel position P1 to the second wheel position P2. When the wheels have been positioned in the second wheel position P2, the transport vehicle V can start driving in the lateral direction DLA along the second pair of parallel track grooves 2b.

[0077] In a second example, the transport vehicle V is driving in the lateral direction DLA along a second pair of parallel track grooves 2b with the wheels arranged in the second wheel position P2. To change driving direction of the transport vehicle V from driving in the lateral direction DLA along the second pair of parallel track grooves 2b to driving in the longitudinal direction DLO along a first pair of parallel track grooves 2a, the transport vehicle V is propelled in the lateral direction DLA and stopped at any track tile module 1 of the modular track system S suitable for changing driving direction. When the transport vehicle V is positioned on the track tile module 1 with each wheel W arranged in a corresponding track groove junction J of the track tile module 1 , as shown in figure 3b, the wheels are rotated from the second wheel position P2 to the first wheel position P1. When the wheels have been positioned in the first wheel position P1 , the transport vehicle V can start driving in the longitudinal direction DLO along the first pair of parallel track grooves 2a. Each of the transport vehicles V have an electric propulsion system and an electric energy storage. The electric propulsion system of the transport vehicle V may be an electric propulsion motor 13 drivingly connected to one or more of the wheels W, with or without an intermediate transmission unit. For example, each wheel W may be equipped with an individual electric propulsion motor 13. T urning of the wheels W may be accomplished by individual electric turning motors or a single common electrical turning motor.

[0078] The electric propulsion system may also include an electronic motor controller that is connected to the electric energy storage 14 and to the electric propulsion motor 13, and which controls the amount of electrical power to be supplied to the electric propulsion motor 13.

[0079] In an alternative configuration of the transport vehicle V shown in figure 4a-b, the transport vehicle V comprises two sets of wheels W. A first set of wheels W1 is configured for driving the transport vehicle V in the first drive lanes Di along first pairs of parallel track grooves 2a of track tile modules 1 arranged in connection to each other. A second set of wheels W2 are configured for driving the transport vehicle V in the second drive lanes D2 along second pairs of parallel track grooves 2b of track tile modules 1 arranged in connection to each other. Each of the first set of wheels W1 and second set of wheels W2 may suitably be arranged as a wheel set that could be raised and lowered relative to the transport vehicle V, as indicated in figure 4a. In a lowered position PL, the set of wheels are used for driving the transport vehicle V, and in a raised position PR, the set of wheels are deactivated from driving the vehicle, as understood from figures 4a-b. In the illustrated embodiment, the first set of wheels W1 are arranged in the lowered position PL and the second set of wheels W2 are arranged in the raised position PR, allowing the transport vehicle V to drive along the first drive lanes Di. The set of wheels are lowered and raised when the transport vehicle V is positioned on a track tile module 1 with each wheel W aligned with a corresponding pair of parallel track grooves.

[0080] Figure 5a schematically shows a section of the driving track structure 2 having a first drive lane Di extending in a first direction, and a second drive lane D2 extending in a second direction that is perpendicular to the first drive lane, and an intersection I between the first and second drive lanes. In this example embodiment, the second drive lane is merely a short track section part that ends with a first shared charging station C1. Shared herein means that it can be used by several different transport vehicles V, i.e. it is shared between several different transport vehicles V.

[0081] The first shared charging station C1 includes a charging connector 15, and the transport vehicle V include corresponding charging connector 16 that is adapted to be connected to the charging connector 15 of the first charging station C1 for enabling charging of the electric energy storage 14 of the transport vehicle V. The charging connectors 15, 16 are for example galvanic connectors, such as plug and socket connectors or similar type of non-wireless charging connectors. Alternatively, the charging connectors 15, 16 are designed for wireless charging, i.e. non-contact connectors.

[0082] Fig. 5a-5c show schematically a charging sequence for a transport vehicle V entering a charging state. In fig. 5a, the transport vehicle V drives along the first drive lane Di. The transport vehicle V has been given the task to drive to the first charging station C1 for charging of its electrical storage system. In figure 5b, the transport vehicle V has reached the intersection I, and has started to drive along the second drive lane D2 towards the first charging station C1 .

[0083] In figure 5c, the charging connector 16 of the transport vehicle V is connected to the charging connector 15 of the first charging station C1 .

[0084] The charging state of a transport vehicle V corresponds to the operating state in which the transport vehicle V is connected to the first charging station C1 via the charging connector 15 of the first charging station C1. When the transport vehicle V becomes disconnected from the charging connector 15 of the first charging station C1 , the charging state of the transport vehicle V ends.

[0085] The prior art solution of autonomous industrial transportation system having a plurality of autonomous self-driving vehicles V often involves having large number of charging stations. For example, it is not uncommon that an autonomous industrial transportation system has the same number of transport vehicles as charging stations, wherein the transport vehicles often may have so called opportunistic charging implemented. This means that each transport vehicle goes to its individual charging station as soon as no new transport task has been assigned to the transport vehicle, i.e. the transport vehicle utilizes the temporary lack of transport task for charging the battery of the transport vehicle. However, this generally requires a large space and cost for acquiring and installing all the charging stations.

[0086] Simply reducing the number of charging stations while keeping the opportunistic charging strategy is also problematic, because this may result in queues to the charging stations after a period of high transport task load, and thus to a situation in which the total available transport capacity is lower than planned.

[0087] Consequently, as described above, one of the problems to be solved by the present disclosure is to provide an autonomous industrial transportation system having a plurality of transport vehicles V and a plurality of shared charging stations, wherein the space and cost associated with acquisition and installation of the plurality of charging stations shall be significantly reduced, while keeping a certain flexibility in terms of transport capacity, such that the autonomous industrial transportation system can handle a certain variation in incoming transport tasks over time.

[0088] This is solved at least partly be providing the autonomous industrial transportation system with relatively few charging stations, in combination with implementation of a new charging strategy that is targeting to continuously keep a relatively small number of transport vehicles in charging state.

[0089] In other words, the charging strategy involves targeting to keep a relatively constant number of transport vehicles in charging state over time, for the purpose of maintaining a relatively constant accumulated charge level of all transport vehicles. This has the advantage that the total number of charging stations can be reduced to a relatively low number relative to the total number of transport vehicles, while also avoiding that the entire fleet of transport vehicles are collectively getting low in charge level at the same time.

[0090] As a result, a minimum planned transport capacity is always ensured, because there is no risk for collective low charge level of a large portion of the fleet of transport vehicles V, in combination with a cost-efficient implementation due to the relatively low number of required charging stations.

[0091] An example embodiment of the autonomous industrial transportation system according to the disclosure will be described with reference to figure 6, which shows an autonomous industrial transportation system comprising a modular track system S comprising a plurality of track tile modules 1 arranged in connection to each other for providing a driving track structure 2.

[0092] The autonomous industrial transportation system further comprises a plurality of selfdriving wheeled transport vehicles V arranged on the driving track structure 2 and having an electric propulsion system 13 and an electric energy storage 14, wherein the driving track structure 2 is configured for guiding wheels W of the transport vehicles V.

[0093] The autonomous industrial transportation system further comprises a plurality of shared charging stations C1 , C2 arranged for enabling charging of the electric energy storage 14 of the transport vehicles V, wherein the total number of shared charging stations C1 , C2 is less than the total number of transport vehicles V, and wherein all of said transport vehicles V have access to and can be charged by any of said shared charging stations C1 , C2.

[0094] The autonomous industrial transportation system further comprises a control system 17 in wireless data communication with the plurality of transport vehicles V, wherein the control system 17 is configured to control the transport vehicles V to maintain a target number N2 of the transport vehicles V in charging state at the charging stations C1 , C2 during operation of the autonomous industrial transportation system.

[0095] The control system 17 may also be referred to as the main control system 17. The control system 17 is a processing control system, i.e. it comprises an electronic processing unit for executing instructions stored in a data memory.

[0096] In the example embodiment of figure 6, the implementer has selected to install two charging stations C1 , C2, and the target number N2 is set to one. This criteria is fulfilled in the time instance depicted by figure 6, because there is a single transport vehicle V in charging state, namely the transport vehicle V #6 currently connected to the first charging station C1. The symbol # herein means “Number”, i.e. V #6 refers to “Vehicle number 6”.

[0097] The transport vehicle V #6 could alternatively have been connected to the second charging station C2. The identity or location of the charging station C1 , C2 is not relevant to the charging strategy, only the number of transport vehicles V being simultaneously charged. The total number of charging stations could in the example embodiment of fig. 6 have been one, i.e. a single charging station C1 , but having a certain amount of redundancy may be useful, for example in case of malfunction or blockage of one charging station. In addition, one or a few additional charging stations enables the control system 17 to increase the target number N2 slightly if required.

[0098] Having a plurality of spread out charging stations C1 , C2 may also be beneficial in terms of reduced driving length for arriving at a free charging station C1 , C2.

[0099] The electric energy storage of the transport vehicle is for example a ultracapacitor and / or a battery, such as a Li-Ion battery, a LFP battery, or the like.

[0100] The plurality of shared charging stations are stationary and installed such that any of the transport vehicles V have access to and can autonomously drive and connect to any of the charging stations C1 , C2 for charging the electric energy storage 14, while still being located on the modular track system S.

[0101] The total number of transport vehicles N3 of an autonomous industrial transportation system is equal to the sum of the number N1 of operational transport vehicles V, i.e. number of vehicles available for performing transport tasks, and the number N of vehicles in charging state, i.e. N3=N1+N. In the example embodiment of figure 6, the parameter N1 is equal to 8, the parameter N is equal to 1 , and the parameter N3 is equal to 9.

[0102] The total number of shared charging stations, which in this example is two, is generally substantially less than the total number of transport vehicles N3, which in this example amounts to nine. The term substantially less refers herein to an arrangement, wherein the total number of charging stations are less than 50%, specifically less than 30%, of the total number N3 of transport vehicles V.

[0103] The control system may for example be implemented as software in a dedicated industrial or general computer located close to the modular track system S for being able to maintain a reliable wireless data communication with the transport vehicles V, for example via wireless LAN, industrial 5G network, wireless broadband, or the like. The control system is configured to control the transport vehicles to maintain a target number N2 of the transport vehicles in charging state at the charging stations during operation of the autonomous industrial transportation system.

[0104] The target number N2 is not necessarily always fulfilled by the control system and there may for example be small time periods having a deviation between the actual number N of transport vehicles in charging state at the charging stations C1 , C2, and the target number N2 of transport vehicles V in charging state at the charging stations C1 , C2.

[0105] For example, according to a first example embodiment of the charging strategy, the control algorithm of the control system will merely instruct a new transport vehicle to drive and connect with a suitable charging station in response to obtaining information that a transport vehicle has completed the charging phase. In other words, there may be a small time gap associated with change of transport vehicle V, in which the actual number N of transport vehicles in charging state will be smaller than the target number N2 of transport vehicles V in charging state.

[0106] This time gap may depend on parameters as the distance of the next transport vehicle to be charged to a suitable charging station C1 , C2, and whether the next transport vehicle to be charged must complete an ongoing transport task before driving to a suitable charging station C1 , C2, and whether there is free passage to the selected charging station C1 , C2 or not, etc.

[0107] In other words, the control system 17 may be deemed being configured to control the transport vehicles V to bring the actual number N of transport vehicles in charging state at the charging stations C1 , C2 towards said target number N2.

[0108] In the schematic illustration of figure 6, the transport vehicles perform repeated transport tasks involving movement of a cargo load 19 from a loading platform 20 to an unloading platform 21. The transport vehicles V receive transport tasks from the control system 17 to pick-up a cargo load 19 at the loading platform 20. This cargo load 19 is subsequently transported by the transport vehicle V over the modular track system S to an unloading platform 21 , where the cargo load 19 is removed from the transport vehicle V. The empty transport vehicle V may then drive back to the loading platform 20 for receiving a new load. The reference #7-20% indicates transport vehicle number No 7 having 20% state of charge (SOC) of the electric energy storage 14.

[0109] Some of the other transport vehicles V, such at #8 are temporarily for example parked, i.e. not moving across track tile module. The arrow indicates a moving transport vehicle V, while the lack of an arrow indicates a parked or still standing vehicle.

[0110] Figure 7 schematically illustrates the number of transport vehicles V in charging state over time for another example of the modular track system S having a certain number of transport vehicles V. The Y-axis denote the number of transport vehicles in charging state, and the X-axis denote operating time in hours of the autonomous industrial transportation system. In this example illustration, the target number N2 is kept constant and set to three. However, the actual number N of transport vehicles V being in charging state is occasionally during small time periods less than three, due to change of transport vehicle V at the charging stations.

[0111] However, when comparing the accumulated amount of time having three transport vehicles in charging state, with the accumulated amount of time not having three transport vehicles in charging state, over a any continuous time period 18, such as for example any three, four, five or six hour period, it is clear that the control system manages to keep the actual number N of transport vehicles in charging state at the charging stations equal to the target number N2 over a significant portion of the time of said time period.

[0112] For example, over a time period 18 of four hours the accumulated amount of time having three transport vehicles in charging state at the charging stations is at least 70%, and over a time period of six hours, the accumulated amount of time having three transport vehicles in charging state at the charging stations is at least 80%.

[0113] This can be compared with the same time period 18 of four hours for the prior art of figure 8, in which the accumulated amount of time having three transport vehicles in charging state at the charging stations is less than 25%.

[0114] Consequently, according to an alternative definition of the new charging strategy according to the disclosure, the control system may be configured to control the transport vehicles to maintain a fixed number of transport vehicles in charging state at the charging stations over an accumulated time of at least 70% of a continuous four hour time period 18, specifically over a continuous six hour time period. This applies during normal operation of the autonomous industrial transportation system, i.e. not during time down periods, such as nights or weekends, or the like.

[0115] As clearly visible in figure 7, the charging strategy according to the present disclosure results in a relatively constant total charging level on the fleet of transport vehicles V.

[0116] The characteristic charging profile of the charging strategy according to the present disclosure schematically illustrated in figure 7 distinguishes significantly from the characteristic charging profile of a more conventional charging strategy, such as opportunistic charging implemented in a system having the same number of charging stations and transport vehicles, as schematically illustrated in figure 8.

[0117] Figure 8 shows that the number of transport vehicles V in charging state varies much more over time, typically in response to the current work load. In other words, during time periods of high work load, only the transport vehicles that must be charged are in charging state, and during time periods of low work load, many of the transport vehicles entering charging state. The disadvantage of the system depicted in figure 8 is the large number of charging stations required. Furthermore, in case of a longer time period of high load, a large number of transport vehicles will have to go into charging state more or less simultaneously, thereby providing a significant drop in transport capacity. Such a drop in transport capacity will not occur in a system utilising the charging strategy of figure 7, despite requiring significant less charging stations.

[0118] The control system is configured to obtain the target number N2 representing the total number of transport vehicles targeted to be in a charging state at the plurality of shared charging stations, and subsequently control the transport vehicles to maintain said target number N2 of the transport vehicles in charging state at the charging stations during operation of the autonomous industrial transportation system.

[0119] The control system may for example obtain the target number N2 based on input from a user operating or setting up the autonomous industrial transportation system. The target number N2 may thus be a predetermined number stored in a physical data memory of the control system 17.

[0120] The control system 17 may also, or alternatively, be configured to determine the target number N2 based on a charging power of each of the plurality of shared charging stations and a collective power consumption of all operational transport vehicles, i.e. all transport vehicles not being in charging state. This is referred to herein as the energy balance method.

[0121] The energy balance method essentially states that the total charging power of all transport vehicles should be approximately equal to the total power consumption of all transport vehicles, such that the total collective charging state of all transport vehicles, or of all operational transport vehicles, remains essentially constant.

[0122] In other words, the control strategy involves determining a target number N2 of transport vehicles to be kept in charging state, such that this energy balance is essentially accomplished.

[0123] This means that the target number N2 corresponds to the minimal number of charging stations for ensuring that a collective state of charge of the entire fleet of transport vehicles V shall be maintained, and not gradually sink.

[0124] In other words, the minimum number of shared charging stations cannot be less than the target number N2, because this would be incompatible with a sustainable collective charge level of the transport vehicles.

[0125] Furthermore, the charging strategy can select a target number N2 of transport vehicles to be in charging state, such that a total charging power of the utilised charging stations is approximately equal to a total power consumption of all operating transport vehicles. This is referred to as the energy balance approach in the present disclosure, i.e. approximately keeping an energy level of all transport vehicles substantially constant.

[0126] In some example embodiments, the target number N2 is an integer value within a

[0127] P vehicle x N'l range determined by equation N2 = — - x C, wherein: P_vehicle is electrical

[0128] P_charger power level of each self-driving wheeled transport vehicle; N1 is total number of operational transport vehicles; P_charger is for example the maximal or rated electrical charging power level of each individual charging station; and C is a constant in the range of 0.5 - 2, specifically in the range of 1 .0 - 1 .5. This control system may thus determine the target number N2 when provided with information about the values of said parameters. The parameter P_vehicle, i.e. the electrical power level of each self-driving wheeled transport vehicle in Watt (Joule / second), may for example be set equal to the rated power level of the transport vehicle, or the accumulated rated power level of the electrical propulsion motors of a transport vehicle. Alternatively, the electrical power level of each self-driving wheeled transport vehicle may be derived from an average power consumption of each individual transport vehicle based on statistical data over a certain time periods, such as for example the most recent 10 min time period, most recent 1h period, most recent 24 hour period, most recent working week, month or year, or the like.

[0129] The parameter N1 is total number of operational transport vehicles, i.e. the number of transport vehicles available for performing the transport tasks. This may be inputted by user based on the character of the transport task. For example, the user may determine the required number of transport vehicle by dividing a total transport requirement, e.g. total items per time unit, with the transport capacity of each transport vehicle, e.g. vehicle items per time unit. This calculation provides a first estimate of the value of the parameter N1 .

[0130] The parameter P_charger is the electrical charging power level of each individual charging station, such as X Watt.

[0131] Finally, the parameter C is a constant in the range of 0.5 - 2, specifically in the range of 1 .0 - 1.5, and is included to compensate for small variations when determining the values of P _vehicle, N1 and P_charger. The parameter C may be set equal to 1 if no compensation is deemed necessary.

[0132] As an example, let’s assume that a new transport system is designed, wherein a total transport task appears to require 30 operational transport vehicles to handle the situation, i.e. N1=30, and that a rated power of each transport vehicle is 30 Watt, and the charging power capacity of a charging station is 300 Watt. This gives an estimated target number N2 = 30 x 30 / 300 = 3, if the parameter C is equal to 1.0. However, for having a certain safety margin, the parameter C is set to 1.3 which gives an estimated target number N2 = 30 x 30 x 1.3 / 300 = 3 x 1.3 = 3.9. The nearest upwards rounded integer is then equal to 4, i.e. target value N2 is set to 4.

[0133] That means that the implementer must acquire a total of at least 30 operational transport vehicles N1 for accomplishing the transport task, in addition to four transport vehicles N that are almost always in charging state, i.e. a total amount of 34 transport vehicles N3.

[0134] An alternative but similar solution involves determining the value of the target number

[0135] N2 within a range determined by equation N2 =

[0136] Collective power consumption of operational vehicles x C. This equation is substantially Maximal power supply of each charger identical to the equation defined above, except that parameter “collective power consumption of operational vehicles" is determined based on the collective power consumption of the entire group of operational vehicles instead of being based on the power consumption of an individual operational vehicle multiplied with the number of operational vehicles.

[0137] In general, the control system is configured to select a target number N2 of transport vehicles to be simultaneously kept in charging state, such that a total charging power of the utilised charging stations is approximately equal to a total average power consumptions of all operating transport vehicles. This is referred to as the energy balance approach in the present disclosure, i.e. keeping a collective energy level of all transport vehicles approximately or substantially constant.

[0138] Clearly, the momentary energy balance will vary over time due to current workload of individual transport vehicles, and this may be compensated for, in the short, medium or long term, by adjusting the target number N2 accordingly.

[0139] In general, the target number N2 is typically less than 30%, specifically less than 20%, of the total number N3 of transport vehicles of an autonomous industrial transportation system. Consequently, the new charging strategy enables significant reduction in number of charging stations, even when the implementer would decide to include a few extra charging stations in the autonomous industrial transportation system for enhancing operational reliability and closeness to the nearest available charging station C1 , C2 for the transport vehicles.

[0140] The target number N2 may be more or less constant over time. In some example embodiments, the target number N2 may be determined at an initial setup of the autonomous industrial transportation system, and thereafter not changed or adjusted. In other example embodiments, the initially set target number N2 may subsequently be slightly adjusted for tuning the autonomous industrial transportation system to a more optimal working process. For example, in case the initially determined target number N2 was too high, and thus results in charging of transport vehicles already having a very high state of charge, the control system 17 may be configured to adjust the target number N2 to a smaller number, at least temporary for a certain time period.

[0141] In some example embodiments, the control system 17 may also, or alternatively, be configured to determine and / or adjust the target number N2 based on a collective charging state of all transport vehicles, or of all operational transport vehicles. In other words, if the collective charging state of all transport vehicles, or of all operational transport vehicles, is high, such as for example above 75% SOC, the control system 17 may adjust the target number N2 to a lower target number N2. Similarly, if the collective charging state of all transport vehicles, or of all operational transport vehicles, is relatively low, such as for example below 30% SOC, the control system 17 may adjust the target number N2 to a higher target number N2.

[0142] Consequently, the control system may be configured to monitor the SOC of all, or the relevant, transport vehicles V and determine a collective charging state of all transport vehicles, or of all operational transport vehicles, and subsequently determine an appropriate target number N2 based on said collective charging state of all transport vehicles, or of all operational transport vehicles.

[0143] For example, the control system may reduce the target number N2 with one in the event that the collective charging state of all transport vehicles, or of all operational transport vehicles, is above a certain SOC level, such as for example 75% SOC, for a certain time period, such as for example a three hour time period. Similarly, the control system may increase the target number N2 with one in the event that the collective charging state of all transport vehicles, or of all operational transport vehicles, is below a certain SOC level, such as for example 40% SOC, for a certain time period, such as for example a three hour time period.

[0144] The term “collective charging state of all transport vehicles” or “collective charging level of all transport vehicles” herein refers for example to the state of charge (SOC) of the entire fleet of transport vehicles of the autonomous industrial transportation system. It can for example be calculated by determining an average SOC of the fleet of transport vehicles, i.e. by summing all SOC-values of the transport vehicles and then dividing by the total number of transport vehicles. The control system 17 may for example periodically request and collect SOC-values from each of the transport vehicles for keeping an updated SOC-list of the transport vehicles. It is noted that the “collective charging state of all transport vehicles” may also be determined based on another parameter that is closely related to SOC, such as for example a collective remaining operating time of all transport vehicles, or a collective remaining driving length of all transport vehicles, or simply some type of collective charging urgency level of all transport vehicles, wherein said charging urgency level of the transport vehicles is derived from or based on, directly or indirectly, the SOC of all of said transport vehicles.

[0145] The above-described charging strategy of the control system can be said to prioritize the task of keeping the number of transport vehicles in charging state constant over the task of completion of a list of transport jobs, unless the target number is adjusted based on current work load.

[0146] According to some example embodiments, the target number is adjusted based on current work load. According to some other example embodiments, the target number is not adjusted based on current work load.

[0147] Figure 9 shows a schematic overview of an example layout of the control system 17, transport vehicles No.1-9 and charging stations C1 , C2 of the example layout of figure 6.

[0148] The communication lines between the control system 17 and the first and second charging stations C1 , C2 are dashed for indicating that this communication line may be omitted. There is in some example embodiment not strictly necessary that the control system 17 controls the operation of the first and second charging stations C1 , C2. They may be simply always in ready state and arranged to supply electrical power according to a predetermined charging rate when a transport vehicle connects thereto. Alternatively, there may be a direct communication between the transport vehicle V and the charging station for controlling the charging current and / or charging voltage of the charging station according to the need of each transport vehicle individually. Still more alternatively, there may be a communication between the control system 17 and the first and second charging stations C1 , C2, as indicated by the dashed lines in figure 9, thereby potentially replacing said direct communication between the transport vehicle V and the charging station, for the purpose of further reducing the cost of the transport vehicles.

[0149] Figure 10 shows a basic layout of the control system 17. The control system 17 may for example include an electronic processor 22, a data memory, 23, a transport vehicle interface 26 for enabling wireless communication between the processor 22 and transport vehicles V, a transport task input 25, and potentially a charging station interface 24.

[0150] Figure 11 shows an example embodiment of a vehicle control system 28 of an individual transport vehicle V. As mentioned above, the electric propulsion system of a transport vehicle V may include an electronic motor controller 27 that is connected to the electric energy storage 14 and to the one or more electric propulsion motors 13 of each individual transport vehicle V for control of the amount of electrical power to be supplied to the one or more electric propulsion motor 13. The electronic motor controller 27 may also be connected to vehicle steering motor(s) 29 for control of the vehicle steering as described with reference to figures 3a-b, or connected to wheel raising and lowering motors / actuator for vehicle steering as described with reference to figures 4a-b.

[0151] The vehicle control system 28 of each transport vehicles V typically also includes an electronic processing control unit 30 that is configured for controlling operation of the transport vehicle V, such as controlling navigation and driving of the vehicle, performing transport tasks, establishing data communication with the main control system 17 for providing vehicle status update and receiving work task instructions, transport tasks, etc. Consequently, electronic processing control unit 30 is connected with the electronic motor controller 27 for controlling driving the vehicle V.

[0152] Furthermore, in this example embodiment, the vehicle control system 28 further comprises a wireless data communication module 31 for establishing data communication with the transport vehicle interface 26 of the main control unit 17, thereby enabling submission of transport tasks, charging tasks, etc. from the main control unit 17 to the vehicle control system 28.

[0153] Furthermore, the vehicle control system 28 may further include a data memory 32 for storing the computer program, software, or firmware to be executed by the electronic processing control unit 30 for controlling the vehicle 1 . An addition, the vehicle control system 28 may further include a I / O interface 33 for enabling receipt and / or submission of sensor and / control signals from / to external sensors and / or actuators of the vehicle V. For example, the vehicle may include a load sensor 34 that detects when a vehicle is carrying a load, and not carrying a load.

[0154] In some example embodiments, the vehicle control system 28 may further include a Battery Management System (BMS) 35 for control of the battery charge level, battery health, battery charging, etc.

[0155] The main control system 17 may thus be configured to include a transport task scheduler, and configured for handling incoming / pending transport assignments and for assigning tasks, such as for example transport tasks, a charging task, etc., to the various transport vehicles.

[0156] Switching from a first vehicle in charging state to a second vehicle in charging state can be performed in various ways and with more or less time gap between the end of charging state of the first vehicle to the start of charging state of the second vehicle.

[0157] According to one example embodiment, the control system will select and instruct a new transport vehicle to drive and connect with a suitable charging station in response to obtaining information that a transport vehicle has completed the charging phase.

[0158] The control system may be configured to select next transport vehicle to be charged at any of the available charging stations based on state of charge (SOC) of the electric energy storage of all the transport vehicles. In other words, the control system may keep an updated list of SOC values of all transport vehicles, or make an enquiry to each transport vehicle, for the purpose of identifying the transport vehicle having the lowest state of charge, and subsequently instruct said transport vehicle to drive to the nearest available charging station.

[0159] In the example layout of figure 6, the control system would have selected transport vehicle #3, because this vehicle has the lowest SOC.

[0160] The control system would instruct transport vehicle #3 to either go directly to the for example charging station C1 , or first after having unloaded the cargo load 19 at the unloading platform 21. The control system may alternatively use another parameter that also represent some type of charging urgency level. For example, the control system may be configured to select next transport vehicle to be charged based on estimated or calculated remaining operating time of all the transport vehicles, and to select the vehicle having the shortest remaining operating time. The remaining operating time until the electric energy storage of the transport vehicles is depleted may be determined based on for example historical operating time and / or load profile. This has the advantage of taking state of heath (SOH) of the electric energy storage into account, because an electric energy storage having poor SOH tend to have shorter remaining operating time despite possibly having a larger SOC, compared with an electric energy storage having good SOH.

[0161] Similarly, the control system may rely on the estimated or calculated remaining driving length of the transport vehicles until electric energy storage of the transport vehicles is depleted, based on for example historical driving length and / or load profile. This has the advantage of taking SOH of the electric energy storage into account.

[0162] Still more alternatively, the control system may be configured to select next transport vehicle to be charged based on some kind of transport vehicle charging urgency index, but also this approach will somehow be connected to current SOC and SOH of the electric energy storages of all transport vehicles.

[0163] The control system may also take additional aspects into account when selecting next transport vehicle to be charged. For example, the control system may take the current location of the transport vehicles on the modular track system S into account. For example, if transport vehicle #3 of figure 6 would have been located far from an available charging station, the control system may have selected transport vehicle #7 instead, because transport vehicle #7 also has a relatively low SOC, and is located very close to both the first and second charging stations C1 , C2, thereby significantly reducing the time gap associated with a transport vehicle charge switch.

[0164] In addition to location, the control system may also take the loading status into account when selecting next transport vehicle to be charged, i.e. whether the transport vehicles first must unload the cargo load or not before driving and connecting with a charging station. This would shift the selection towards transport vehicle #7 in figure 6 even more, because #7 is empty and directly ready for charging, while #3 first must go unloading.

[0165] Similarly, the control system may alternatively use another parameter that also represent some type availability index for charging, instead of location. For example, the control system may be configured take calculated or estimated driving length of the transport vehicle to an available charging station, or estimated or calculated driving time of the transport vehicles to an available charging station, into account when selecting next transport vehicle to be charged.

[0166] The initiative for changing the transport vehicle at the charging station may come from the currently charged transport vehicle, or from the control system. For example, the currently charged transport vehicle may simply terminate charging at its own initiative when reaching a certain charge level, such as for example in the range of 70-80% SOC. Alternatively, the control system is configured to initiate change of transport vehicle based on certain criteria.

[0167] For example, the control system may be configured to initiate change of transport vehicle when the currently charged vehicle at the charging station has a state of charge at or above a predetermined level, such as for example in the range of 70- 80% SOC.

[0168] Alternatively, the control system may be configured to initiate change of transport vehicle when the transport vehicles to be charged next at the charging station has a state of charge below a predetermined level, such as for example below 20% SOC. In other words, the control system may order a switch in charging vehicle earlier than normally planned due to charging urgency of another vehicle.

[0169] Similarly, other urgency parameters may be used for the same reason. Hence, the control system may be configured to initiate change of transport vehicle when an estimated or calculated remaining operating time of the transport vehicle to be charged next is below a predetermined level, such as for example 30-60 min. This has the advantage of taking into account SOH of the electrical energy storage 14 of the transport vehicle to be charged next, based on for example historical operating time and / or load profile. Yet another urgency parameter is remaining driving length. Hence, the control system may be configured to initiate change of transport vehicle when an estimated or calculated remaining driving length of the transport vehicle to be charged next is below a predetermined level, such as for example about 1000 - 3000 m. This has the advantage of taking into account SOH of the electrical energy storage 14 of the transport vehicle to be charged next, based on for example historical operating time and / or load profile.

[0170] The control system may be configured to initiate change of transport vehicle when the transport vehicle to be charged next has a charging urgency index above a predetermined level.

[0171] Still more alternatively, the control system may be configured to initiate change of transport vehicle when a predetermined number or percentage of all transport vehicles has a state of charge or remaining operating time or remaining driving length below a predetermined charge level or a charging urgency level above a predetermined level. In other words, the control system may be configured to initiate change of transport vehicle when for example more than 30% of all transport vehicles has a SOC below 30% SoC, or estimated or calculated remaining driving time below 60 min, or estimated or calculated remaining driving length below 3000 m. This may trigger a charge of transport vehicle based on criteria of a set of vehicles and not only a single vehicle.

[0172] When targeting to implement an autonomous industrial transportation system having the smallest possible number of charging stations, it is relevant to keep said time gap associated with vehicle charging switches short. Consequently, according to a further example embodiment, the control system may control also the transport vehicle that is about to terminate the charging state to remain a little longer in charging state, for the purpose of allowing the subsequent transport vehicle to get close and ready for the charging process. Thereby, the time gap can be minimized, thereby enabling installation and use of a minimal amount of charging stations, for further cost savings.

[0173] Specifically, the control system may be configured to, after a change of transport vehicle has been initiated, i.e. decided that the change from a first to a second transport vehicle in charging state should occur, control the transport vehicle currently located at the charging station to depart from the charging station based on: the position of the transport vehicle to be charged next, or the remaining driving length of the transport vehicle to be charged next to an available charging station, or the remaining driving time of the transport vehicle to be charged next to an available charging station. Available charging stations here refers to all the empty charging stations, as well as the charging station from which the vehicle is about the depart. This means that the transport vehicle that is about to leave a charging station may be controlled to remain a little longer than planned because the transport vehicle to be charged next is not yet ready for a switch, and the time gap would thus be unnecessary long.

[0174] It is generally undesirable for a transport vehicle V to enter a charging state at a charging station while still carrying a cargo load 19, because this would significantly prolong the time for completing the ongoing transport task of that transport vehicle.

[0175] As a result, it would be beneficial if some or all of the charging stations are located in region of the transport route network where the transport vehicles normally do not carry any cargo, such as for example after a goods delivery point and on the way to the next goods loading point.

[0176] Alternatively, or in combination with above, it would be beneficial if some or all of the charging stations are located in region of the transport route network that corresponds to a high traffic region. Thereby, the likelihood that the transport vehicle is close to the charging station is higher, and useless driving to the charging station can be minimized.

[0177] In some example embodiments of the autonomous industrial transportation system, each of the one or more charging stations is rigidly attached to a track tile module. This ensures high operational reliability.

[0178] In some example embodiments, the autonomous industrial transportation system comprises one or more dedicated charging track tile modules that are different from the track tile modules that are forming the driving track, and wherein each of the one or more charging stations are located on, and fastened to, a charging track tile module.

[0179] With reference to figure 12, the present disclosure also relates of a method and software algorithm for controlling charging of a plurality of self-driving wheeled transport vehicles of an autonomous industrial transportation system, wherein the autonomous industrial transportation system comprises a modular track system S comprising a plurality of track tile modules 1 arranged in connection to each other for providing a driving track structure 2, wherein the driving track structure 2 is configured for guiding wheels W of the transport vehicles V.

[0180] Specifically, the flowchart of figure 12 schematically illustrates the basic steps of one example embodiment of a software algorithm for controlling operation of the control system 17 of the industrial transportation system.

[0181] The method comprises a first step S1 of controlling the transport vehicles to maintain a target number N2 of the transport vehicles in charging state at the charging stations during operation of the autonomous industrial transportation system. Thereby, the total number of charging stations can be effectively reduced for cost-saving purposes.

[0182] The autonomous industrial transportation system further comprises: a plurality of selfdriving wheeled transport vehicles arranged on the driving track structure 2 and having an electric propulsion system and an electric energy storage, wherein the driving track structure 2 is configured for guiding wheels W of the transport vehicles V; and a plurality of shared charging stations arranged for enabling charging of the electric energy storage of the transport vehicles, wherein the total number of shared charging stations is less than the total number of transport vehicles, and wherein all of said transport vehicles have access to and can be charged by any of said shared charging stations.

[0183] The method and software algorithm described above with reference to figure 12 may include an initial step SO of obtaining a target number N2 representing a total number of transport vehicles targeted to be in a charging state at the plurality of shared charging stations during operation of the autonomous industrial transportation system. The step of obtaining a target number N2 may be performed by determining a suitable target number N2 using any of the methods described hereinabove.

[0184] As described above, the method, flowchart and software algorithm for controlling the transport vehicles to maintain a target number N2 of the transport vehicles in charging state at the charging stations during operation of the autonomous industrial transportation system can be implemented in various ways. One relatively straightforward example method and algorithm for maintaining a target number N2 of the transport vehicles in charging state during operation of the autonomous industrial transportation system is described below with reference to figure 13, which starts with the initial step SO of obtaining the target number N2.

[0185] The previously described first step S1 of controlling the transport vehicles to maintain a target number N2 of the transport vehicles in charging state at the charging stations during operation of the autonomous industrial transportation system is here described in more detail and includes a substep S12 of determining the actual number of vehicles N currently in charging state, including vehicles that has received instructions to drive to a charging station and thus are on the way to a charging station.

[0186] At a subsequent substep S13, said actual number N is compared with the target number N2. If the actual number N is lower than the target number N2, i.e. N<N2, the method proceeds to a final substep S14 and an additional, i.e. a new vehicle V is instructed to drive to and connect with a charging station for initiating charging of the battery 14 for increasing the total number of vehicles at a charging station. The new vehicle may be selected based on any of the methods for selecting next vehicle to be charged described hereinabove. If the actual number N of vehicles is not lower than the target number N2, for example when N=N2 or N>N2, the method returns to substep S12 for renewed determination of the actual number of vehicles N currently in charging state.

[0187] As described above, in some implementation it may be desirable to perform a regular or irregular or periodic update of the target number N2, for adapting the target number N2 to long term variations in the transport system behaviour, or the like. Figure 14 schematically shows a flowchart and software algorithm representing an example embodiment for implementing such a method. The previously described first step S1 of controlling the transport vehicles to maintain a target number N2 of the transport vehicles in charging state at the charging stations during operation of the autonomous industrial transportation system is thus here described in more detail and includes a first substep S10 of determining whether the current target number N2 needs to be adjusted for some reason, such as for adjusting the overall charge level of the fleet of transport vehicles, or the like, as described above.

[0188] If the underlying criteria for determining an appropriate target number N2 indicates that the current target number N2 need adjustment, i.e. the evaluation is “YES” in first substep S10, the flowchart proceeds to substep S11 where a new target number N2 is determined or adopted. For example, the adjustment of the target number N2 may involve increasing the target number with one or more, or decreasing the target number with one or more. The method subsequently proceeds further to substep S12 as described with reference to figure 13.

[0189] The step of adjusting the target number N2 may be performed by determining a suitable new target number N2 using any of the methods described hereinabove. Moreover, an indication signalling need for adjustment of the target number N2 may be based on for example a change in average energy level of all transport vehicles exceeding a threshold value or being outside a predetermined range interval, or simply when a difference between the currently used target value N2 and a recalculated target value N2 based on current operating conditions differs more than a predetermined threshold level.

[0190] On the other hand, if the underlying criteria for determining an appropriate target number N2 in first substep S10 indicates that the current target number N2 does not need adjustment, i.e. the evaluation is “No” in first substep S10, the flowchart proceeds to directly to substep S12 as described with reference to figure 13.

[0191] Many further alterative control strategies for controlling operating of the control system 17 of the industrial transportation system are of course possible, as described in the present description.

[0192] Operation of the individual vehicles V may be implemented in various ways. Specifically, according to some example embodiments, each individual vehicle V may be operated with a large degree of autonomy, wherein high level transport tasks are received from the main control unit 17 and subsequently performed largely autonomously by the vehicles V.

[0193] One example embodiment of a method and software algorithm for an operating control strategy of the electronic processing control unit 30 of the vehicle control system 28 of a vehicle V is described with reference to a flowchart of figure 15, which includes a first step S20 of receiving a transport task from the main control unit 17 and performing said transport task. After finalising the transport task the vehicle checks in step S21 whether it has received a charging task, i.e. instructions for driving to and connecting with a charging station. If the answer to this check is YES the control strategy proceeds to step S22 in the flow chart. Step S22 involves for example driving to and connecting with a predetermined or selected or nearest or non-occupied charging station and stay there until instructions to leave the charging station is received from the main control unit 17, or alternatively until the State of Charge has reached a predetermined value, or the like, and subsequently proceeding to the first step S20 again, for receiving the next transport task.

[0194] However, if the answer to said check is NO, i.e. no charging instructions has been received, the control strategy may proceed directly back to the first step S20 for receiving the next transport task.

[0195] Many alterative control strategies for controlling operating of the electronic processing control unit 30 of the vehicle control system 28 are of course possible, as described in the present description. For example, the electronic processing control unit 30 of the vehicle control system 28 may simply have task list that may include both transport tasks and charging task, wherein the vehicle control system 28 is configured to process each task sequentially based on priority or receipt order, or the like.

[0196] The present disclosure has been presented above with reference to specific embodiments. However, other embodiments than the above described are possible and within the scope of the disclosure. Different method steps than those described above, performing the method by hardware or software, may be provided within the scope of the disclosure.

[0197] The methods disclosed herein may be implemented in a general purpose computer, a processor, or a processor core. Suitable processors include, by way of example, a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), and / or a state machine.

[0198] The methods provided herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable storage medium for execution by a general purpose computer or a processor. Examples of computer-readable storage mediums include a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs).

[0199] It will be appreciated that the above description is merely exemplary in nature and is not intended to limit the present disclosure, its application or uses. While specific examples have been described in the specification and illustrated in the drawings, it will be understood by those of ordinary skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure as defined in the claims. Furthermore, modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof.

[0200] Therefore, it is intended that the present disclosure not be limited to the particular examples illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out the teachings of the present disclosure, but that the scope of the present disclosure will include any embodiments falling within the foregoing description and the appended claims. Reference signs mentioned in the claims should not be seen as limiting the extent of the matter protected by the claims, and their sole function is to make claims easier to understand.

[0201] REFERENCE SIGNS

[0202] 1 : Track tile module 35 27: Motor controller

[0203] 2: Driving track structure 28: Vehicle control system

[0204] 2a: First pair of parallel track 29: Vehicle steering motor grooves 30: Electronic processing control

[0205] 2b: Second pair of parallel track unit grooves 40 31: Data communication module

[0206] 3: Base structure 32: Data memory

[0207] 5a: Upper side 33: I / O interface

[0208] 5b: Lower side 34: Sensor

[0209] 6a: First longitudinal side edge 35: BMS

[0210] 6b: Second longitudinal side edge 45 C1 : First charging station

[0211] 7a: First lateral side edge C2: Second charging station

[0212] 7b: Second lateral side edge D First drive lane

[0213] 8a: Protruding section D2: Second drive lane

[0214] 8b: Recessed section DLA: Lateral direction

[0215] 9: Locking arrangement 50 DLO: Longitudinal direction

[0216] 12: Reinforcing rib DVE: Vertical direction

[0217] 13: Electric propulsion motor G1: First track gauge

[0218] 14: Electric energy storage G2: Second track gauge

[0219] 15: Charging connector of charging I: Intersection station 55 J: Track groove junction

[0220] 16: Charging connector of transport N1 : Total number of operational vehicle transport vehicles

[0221] 17: Control system N2: Total number of vehicles in

[0222] 18: Time period charging state

[0223] 19: Cargo load 60 N3: Total number of transport

[0224] 20: Loading platform vehicles

[0225] 21: Unloading platform P1: First wheel position

[0226] 22: Electronic processor P2: Second wheel position

[0227] 23: Data memory S: Modular track system

[0228] 24: Charging station interface 65 V: Transport vehicle

[0229] 25: Transport task input W: Wheel

[0230] 26: Transport vehicle interface

Claims

CLAIMS1. An autonomous industrial transportation system comprising: a modular track system (S) comprising a plurality of track tile modules (1) arranged in connection to each other for providing a driving track structure (2); a plurality of self-driving wheeled transport vehicles (V) arranged on the driving track structure (2) and having an electric propulsion system and an electric energy storage (14), wherein the driving track structure (2) is configured for guiding wheels (W) of the transport vehicles (V); a plurality of shared charging stations (C1 , C2) arranged for enabling charging of the electric energy storage (14) of the transport vehicles (V), wherein the total number of shared charging stations (C1 , C2) is less than the total number of transport vehicles (V), and wherein all of said transport vehicles (V) have access to and can be charged by any of said shared charging stations (C1 , C2); and a control system (17) in communication with the plurality of transport vehicles (V), wherein the control system (17) is configured to control the transport vehicles (V) to maintain a target number (N2) of the transport vehicles (V) in charging state at the charging stations (C1 , C2) during operation of the autonomous industrial transportation system.

2. The autonomous industrial transportation system according to claim 1 , wherein a minimum number of shared charging stations (C1 , C2) is not less than the target number (N2).

3. The autonomous industrial transportation system according to any of the preceding claims, wherein the target number (N2) is an integer value within a range determined by equation N2 =p-vehlcle x N1xQ wherein:P_chargerP_vehicle is electrical power level of each self-driving wheeled transport vehicle (V);N1 is total number of operational transport vehicles (V);P_charger is electrical charging power level of each individual charging station (C2, C2); andC is a constant in the range of 0.5 - 2, specifically in the range of 1 .0 - 1 .5.

4. The autonomous industrial transportation system according to any of the preceding claims, wherein the control system (17) is configured to determine the target number (N2) based on: a charging power level of each of the plurality of shared charging stations (C1 , C2) and collective power consumption of all operational transport vehicles (V); and / or a collective charging state of all transport vehicles (V) or of all operational transport vehicles (V).

5. The autonomous industrial transportation system according to any of the preceding claims, wherein the target number (N2) is less than 30%, specifically less than 20%, of the total number of transport vehicles (V) or of all operational transport vehicles (V).

6. The autonomous industrial transportation system according to any of the preceding claims, wherein the control system (17) is configured to prioritize keeping the target number (N2) of transport vehicles (V) in charging state at the charging stations (C1 , C2) during operation of the autonomous industrial transportation system, over processing of incoming / pending transport assignments.

7. The autonomous industrial transportation system according to any of the preceding claims, wherein the control system (17) is configured to select next transport vehicle (V) to be charged at any of the charging stations (C1 , C2) based on one or more of the following parameters: state of charge of the electric energy storages (14) of the transport vehicles (V); remaining operating time of the transport vehicles (V); remaining driving length of the transport vehicles (V); location of the transport vehicles (V); driving length of the transport vehicles (V) to a charging station (S1 , S2); driving time of the transport vehicles (V) to a charging station (S1 , S2); transport vehicle charging urgency level.

8. The autonomous industrial transportation system according to any of the preceding claims, wherein the control system (17) is configured to control the transport vehicles (V), such that the transport vehicle (V) selected to be charged next, will be assigned to drive to the nearest available charging station (C1 , C2).

9. The autonomous industrial transportation system according to any of the preceding claims, wherein the control system (17) is configured to initiate change of transport vehicle (V), at a charging station (C1 , C2), based on one or more of the following events and / or parameters:- when the currently charged vehicle (V) at the charging station (C1 , C2) has a state of charge at or above a predetermined level;- when the transport vehicle (V) to be charged next has a state of charge below a predetermined level;- when remaining operating time of the transport vehicle (V) to be charged next is below a predetermined level;- when remaining driving length of the transport vehicle (V) to be charged next is below a predetermined level;- when charging urgency index of the transport vehicle (V) to be charged next is above a predetermined level;- when a predetermined number or percentage of all transport vehicles (V) has a state of charge or remaining operating time or remaining driving length below a predetermined charge level or a charging urgency level above a predetermined level.

10. The autonomous industrial transportation system according to any of the preceding claims, wherein the control system (17) is configured to, after a change of transport vehicle (V) at a certain charging station (C1 , C2) has been initiated, control the transport vehicle (V) currently located at the charging station (C1 , C2) to depart from the charging station (C1 , C2) based on: the position of the transport vehicle (V) to be charged next; or the remaining driving length of the transport vehicle (V) to be charged next to an available charging station (C1 , C2); or the remaining driving time of the transport vehicle (V) to be charged next to an available charging station (C1 , C2).

11. The autonomous industrial transportation system according to any of the preceding claims, wherein each of the shared charging stations (C1 , C2) include a charging connector (15), and wherein each of the transport vehicles (V) include corresponding charging connector (16) that is adapted to be connected to the charging connector (15) of the charging station (C1 , C2) for enabling charging of the electric energy storage (14) of the transport vehicle (V).

12. The autonomous industrial transportation system according to any of the preceding claims, wherein the control system (17) is configured for assigning the task of driving to a charging station (C1 , C2) in a state when the transport vehicle (V) is not carrying any cargo.

13. The autonomous industrial transportation system according to any of the preceding claims, wherein some or all of the charging stations (C1 , C2) are located: in region of the transport route network where the transport vehicles (V) normally do not carry any cargo, and / or in region of the transport route network that corresponds to a high traffic region.

14. The autonomous industrial transportation system according to any of the preceding claims, wherein a total number of charging stations (C1 , C2) is less than 50%, specifically less than 30%, of a total number of transport vehicles (V).

15. The autonomous industrial transportation system according to any of the preceding claims, wherein each of the charging stations (C1 , C2) is rigidly attached to a track tile module (1), or wherein the autonomous industrial transportation system comprises one or more dedicated charging track tile modules that are different from the track tile modules (1) that are forming the driving track (T), and wherein each of the charging stations (C1 , C2) are located on, and fastened to, a charging track tile module.

16. A method for controlling charging of plurality of self-driving wheeled transport vehicles (V) of an autonomous industrial transportation system, wherein the autonomous industrial transportation system comprises a modular track system (S) comprising a plurality of track tile modules (1) arranged in connection to each other for providing a driving track structure (2), wherein the driving track structure (2) is configured for guiding wheels (W) of the transport vehicles (V), wherein the method comprises controlling the transport vehicles (V) to maintain a target number (N2) of the transport vehicles (V) in charging state at the charging stations (C1 , C2) during operation of the autonomous industrial transportation system.

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