System and method for assigning electric machines

Abstract

A system for assigning electric vehicles, wherein the system includes a plurality of electric vehicles, each of the electric vehicles being provided with a battery system, each of the electric vehicles being provided with a regenerative recharging system arranged to recharge the battery system as the electric vehicle travels downhill, and a control system which is arranged to account for downhill routes in determining assignments of the electric vehicles.

Description

[0001] SYSTEM AND METHOD FOR ASSIGNING ELECTRIC MACHINES

[0002] Field of the Invention

[0003] The present invention relates generally to a system and method for assigning electric machines and, more particularly, but not exclusively, to a system and method for route planning optimisation of electric haul trucks at a mine site.

[0004] Background to the Invention

[0005] It is known to use electric haul vehicles at a mine site, however the applicant has identified that, with existing systems, there are inefficiencies in the way in which the electric haul vehicles are recharged. More specifically, the applicant has identified that existing systems may recharge electric haul vehicles prematurely which leads to inefficiencies as there may not be full utilisation of the vehicle battery life. Also, existing systems for task allocation of electric haul vehicles may have inefficiencies from the vehicles not being fully utilised in a productive sense, for example when vehicles are stopped in a queue and / or in traffic.

[0006] Examples of the present invention seek to provide an improved system and method for assigning electric vehicles which obviate or at least alleviate one or more disadvantages of existing electric vehicle systems, or which at least provide a useful alternative.

[0007] Summary of the Invention

[0008] In accordance with one aspect of the present invention, there is provided a method of assigning electric haul vehicles, wherein the method includes the steps of assigning the electric haul vehicles to productive tasks, and accounting for energy use of the electric haul vehicles.

[0009] In accordance with another aspect of the present invention, there is provided a method of assigning electric vehicles, wherein the method includes the steps of providing each of the electric vehicles with a battery system, providing each of the electric vehicles with a regenerative recharging system, arranging the regenerative recharging system to recharge the battery system as the electric vehicle travels downhill, and accounting for downhill routes in determining assignments of the electric vehicles.

[0010] In accordance with another aspect of the present invention, there is provided a system for assigning electric vehicles, wherein the system includes a plurality of electric vehicles, each of the electric vehicles being provided with a battery system, each of the electric vehicles being provided with a regenerative recharging system arranged to recharge the battery system as the electric vehicle travels downhill, and a control system which is arranged to account for downhill routes in determining assignments of the electric vehicles.

[0011] Preferably, the system includes a mine site and the electric vehicles are electric haul vehicles for carting bulk material across said mine site. More preferably, the system includes at least one charging station for charging the electric vehicles. Even more preferably, the system includes a plurality of charging stations for charging the electrical vehicles.

[0012] In a preferred form, the control system accounts for unproductive statuses of the electric vehicles in determining assignments of the electrical vehicles to optimise productivity of the mine site. More preferably, the control system accounts for unproductive statuses including travel of an electric vehicle to a charging station, travel of an electric vehicle from a charging station, and charging of an electrical vehicle at a charging station.

[0013] Preferably, the control system automatically assigns the electric vehicles to productive tasks. More preferably, the control system automatically assigns the electric vehicles to productive tasks such that charging of the electric vehicles is planned.

[0014] More preferably, the control system automatically assigns the electric vehicles to productive tasks such that slope of terrain of the mine site and downhill regenerative recharging of the electric vehicles are accounted for in calculating estimated recharge time of the electric vehicles.

[0015] Preferably, the control system automatically assigns the electric vehicles to productive tasks accounting for consumption of energy from the battery system.

[0016] In a preferred form, the control system automatically assigns the electric vehicles to productive tasks including optimisation of a speed target of each electric vehicle based on energy use. More preferably, the control system may vary a speed target of an electrical vehicle over a route.

[0017] Preferably, the control system automatically assigns the electric vehicles to productive tasks to maximise productivity of the system.

[0018] It is preferred that each electric vehicle is provided with a battery control module for reporting a charge level of the battery system of the electric vehicle to the control system.

[0019] Preferably, the control system is a central control system.

[0020] In a preferred form, the control system sends an electric vehicle to a recharging station based on proximity of the electric vehicle relative to the recharging station in combination with the recharging station being available.

[0021] Preferably, the control system automatically plans a route of an electric vehicle based on slope of terrain of the mine site.

[0022] In a preferred form, the control system automatically plans a route of an electric vehicle based on traffic flow of the electric vehicles.

[0023] Preferably, the control system sends an electric vehicle to a recharging station based on charge level of the battery system of the electric vehicle.

[0024] In accordance with another aspect of the present invention, there is provided a method of assigning battery-powered machines, wherein the method includes the steps of assigning the battery-powered machines to productive tasks, and accounting for energy use of the battery-powered machines.

[0025] In accordance with another aspect of the present invention, there is provided a system of assigning a battery-powered vehicle, wherein the system includes an autonomous electric vehicle having a battery for powering a drive system of the autonomous electric vehicle, a work site having a charging station for recharging said battery, and an off-board system for issuing commands to the autonomous electric vehicle, wherein the autonomous electric vehicle includes an on-board charge telemetry unit for communicating current charge level of the battery to the off-board system, and the off-board system is arranged to issue a recharge command to the autonomous electric vehicle in response to a charge prediction that the battery will have charge below a threshold value.

[0026] Preferably, the off-board system includes a charge level prediction module, an assignment optimiser and a charge command dispatcher, wherein the charge level prediction module communicates with the assignment optimiser to predict a charge level for particular work allocated, and wherein the charge command dispatcher issues a recharge command to the autonomous electric vehicle when the predicted charge level is below a threshold value. More preferably, the threshold value is a percentage threshold proportion of full charge.

[0027] Brief Description of the Drawing

[0028] The invention is described, by way of non-limiting example only, with reference to the accompanying drawing in which:

[0029] Figure 1 shows diagrammatically a system of task management of electric vehicles in accordance with an example of the present invention.

[0030] Detailed Description

[0031] With reference to Figure 1, there is shown a system 10 of assigning a battery-powered vehicle, wherein the system includes an autonomous electric 12 vehicle having a battery for powering a drive system of the autonomous electric vehicle 12, a work site having a charging station for recharging said battery, and an off-board system 14 for issuing commands to the autonomous electric vehicle 12. The autonomous electric vehicle 12 includes an on-board charge telemetry unit 16 for communicating current charge level of the battery to the off- board system 14. The off-board system 14 is arranged to issue a recharge command 18 to the autonomous electric vehicle 12 in response to a charge prediction that the battery will have charge below a threshold value.

[0032] As shown in Figure 1, the off-board system 14 may include a charge level prediction module 20, an assignment optimiser 22 and a charge command dispatcher 24, wherein the charge level prediction module 20 communicates with the assignment optimiser 22 to predict a charge level for particular work allocated, and wherein the charge command dispatcher 24 issues said recharge command 18 to the autonomous electric vehicle 12 when the predicted charge level is below a threshold value. The threshold value may be a percentage threshold proportion of full charge.

[0033] Accordingly, the system 10 may implement a "hard-stop" command whereby battery-operated autonomous vehicles 12 are automatically sent recharge instructions when their battery depletes to a specific level, in contrast to reliance on an operator sending a manual command. The applicant has determined that each autonomous electric vehicle (or other asset) will have a battery control module which will be able to report its current charge levels. Off-board, there may be provided a battery management system which will be able to predict charge consumption rates for particular work allocated, including taking particular routes.

[0034] In one example, the applicant has determined that it would be beneficial for there to be provided a battery-powered "green fleet" with the installation of a plurality of fast charging stations around a mine site. It is recognised by the applicant that time spent by vehicles travelling to and from a charging station, and the charging time itself, are non- effective production activities which can impact the productivity of a mine. Examples of the present invention involve an optimisation of the system which is used for assigning tasks to autonomous vehicles, such that vehicle downtime at charging stations is minimised.

[0035] In developing the above, the applicant has determined that the optimised assignment of tasks of electric vehicles may be achieved a number of ways, including one or more of the following:

[0036] Opportunistic Charging - effectively instructing vehicles to recharge when they can as opposed to waiting for a manual instruction or hard stop. The vehicles could be commanded to recharge during idle times and could be sent for top up charging when travelling between production tasks.

[0037] Examples of the present invention may plan future assignments and, even if these assignment decisions change, it is possible to plan a future recharge assignment. The "opportunistic" aspect may result in a daisy chain of assignments that result in less travel empty (empty of payload) to recharge of an electric haul truck. For example, the assignments may include go to A, go to B, go to recharge, where the travel from A to B and recharge are the shortest travel empty times / di stances.

[0038] The recharge may also be opportunistic by recharging when the recharge facility is close and has no queue, rather than when the battery levels are at critically low levels. Because queue time will be measured as part of time cost, and because it is desirable to look ahead to refuel options over a period of time (e.g. 24 hours), the applicant has determined that it may be possible to evaluate the best time to move out of a productive mode and into a refuel mode.

[0039] Elevation Change Awareness - taking into account elevation changes when assigning recharge instructions to vehicles, with batteries regenerating charge when travelling downhill. For example, this form of route planning optimisation may involve the electric vehicles being rerouted to allow them to charge the batteries by moving downhill.

[0040] It has been determined that route planning may provide several route options, where some routes are shorter by distance, some routes are shorter by time, some routes consume less energy, and some routes provide some energy gain and perhaps less net energy consumption. The assignment engine may utilise these options to determine which assignment and route are better for both now and in the context of future assignments. It is foreseen that route planning and / or vehicle selection for production activities may be impacted by route planning for recharge instructions, or vice versa.

[0041] Optimising Traffic Flow - minimising vehicle stop times at intersections by varying vehicle speeds along the route. Energy consumption of the vehicles may be reduced by reducing acceleration events. In addition, the risk of accidents can also be minimised in this way.

[0042] In the current mining setting, fuel may not be a limitation. Furthermore, where an aim is to have net zero emissions this may drive a move from diesel fuel powered haul trucks to battery-powered haul trucks which have been charged with "green" energy. With a switch to green energy at site, it is anticipated that there may not be limitless energy at all times. That is, it is anticipated that there may be energy constraints at particular points of the day, depending on supply and demand. This would require a change in ideology using machines on the ground to achieve the most production from those machines with the energy available. This could mean achieving the planned production with the minimum energy spent or, alternatively, achieving the most production with an energy budget, or something in between.

[0043] Some current mining practices do not minimise energy / fuel spent or machines utilised. It is expected that up to 30% fuel / energy may possibly be saved on the energy required to move bulk material using optimisation methods according to examples of the present invention. This saved energy may then be used in other more critical functions such as in an iron ore processing facility operation rather than switching off that operation during energy limiting times.

[0044] An indirect outcome of minimising energy spent is that machines that are not needed may be switched off. By optimising the way that a fleet of electric vehicles is used, both the fleet size and energy consumption may be reduced. It is foreseen that a significant reduction in the order of 10% smaller fleet size may be achieved using this optimisation.

[0045] Another benefit of examples of the invention may be in avoiding adverse effects on a supply chain, particularly by ensuring product is made for customers. That is, another part of the supply chain, such as other sites contributing to the same product, will rally to buffer any issues from one site not contributing the promised amount of product.

[0046] Accordingly, examples of the present invention may provide a system for assigning electric haul trucks to productive tasks, accounting for energy use. Advantageously, the applicant has developed a battery system for haul trucks that can regenerate power as the truck travels downhill, and examples of the present invention utilise that technology. Fast charging units may be placed strategically around a mine site, however travelling to and from a charge station and charging itself, are non-effective production activities that can impact the productivity of a mine. The system proposed is able to automatically assign the trucks / machines to productive tasks such that: charging activities are planned and accounted for

[0047] - the slope of the terrain is accounted for in calculating estimated recharge time, i.e. the trucks gain some charge benefit as they travel downhill the consumption of energy from the battery system is accounted for in the assignment speed target of the machine is optimised for energy use and may vary over the route

[0048] - the overall system is as productive as possible site wide energy constraints and limits are strictly met

[0049] Examples of the invention may have the benefit that the machines will not recharge too early or too late, leading to loss in productivity. Furthermore, the haulage network may as a result be more efficient with respect to fuel consumption and generation. The applicant has identified that charging too late of a machine on a mine site may create a safety hazard by forcing more humans to enter the mining zone.

[0050] Examples may enable consideration of expended energy in assignments and an ability to issue speed profiles for autonomous trucks to follow. There may also be provided the ability to optimise energy expended. Consideration may be given to the battery state on a truck in the issuing of assignments. Examples of the invention may provide the ability to optimise (i.e. daisy chain) a sequence of assignments on the way to refuel or recharge and / or the ability to have energy constraints (e.g. lower energy availability for recharge during the night shift). There may also be the ability to issue assignments to meet a plan while minimising energy consumption.

[0051] The applicant has identified that typical assignments in a Fleet Management System (FMS) are not optimised and that there is an opportunity for more efficiency to assign tasks to give more production. As such, examples of the present invention are able to use global optimisation when assigning tasks. Moreover, "Green Fleets" have further issues owing to battery charge and opportunities for recharging. Advantageously, examples of the present invention may provide an intelligent system which is able to reduce queues at a charging station and reduce charging at sub-optimal times, for example at night time when solar energy is unavailable. With regard to the above, another aspect provides a method of assigning electric haul vehicles, wherein the method includes the steps of assigning the electric haul vehicles 12 to productive tasks, and accounting for energy use of the electric haul vehicles 12. There is also provided a method of assigning electric vehicles, wherein the method includes the steps of providing each of the electric vehicles 12 with a battery system, providing each of the electric vehicles 12 with a regenerative recharging system, arranging the regenerative recharging system to recharge the battery system as the electric vehicle 12 travels downhill, and accounting for downhill routes in determining assignments of the electric vehicles 12.

[0052] Another aspect provides a system 10 for assigning electric vehicles, wherein the system includes a plurality of electric vehicles 12, each of the electric vehicles 12 being provided with a battery system and a regenerative recharging system arranged to recharge the battery system as the electric vehicle travels downhill. A control system, which may be in the form of an off-board system 14, is arranged to account for downhill routes in determining assignments of the electric vehicles 12.

[0053] The system 10 may include a mine site and the electric vehicles 12 may be in the form of electric haul vehicles for carting bulk material across the mine site. The system 10 may include at least one charging station for charging the electric vehicles 12. The system 10 may have a plurality of charging stations for charging the electrical vehicles 12.

[0054] The control system 14 may account for unproductive statuses of the electric vehicles 12 in determining assignments of the electrical vehicles 12 to optimise productivity of the mine site. The control system 14 may account for unproductive statuses including travel of an electric vehicle 12 to a charging station, travel of an electric vehicle 12 from a charging station, and charging of an electrical vehicle 12 at a charging station.

[0055] The control system 14 may automatically assign the electric vehicles 12 to productive tasks such that charging of the electric vehicles 12 is planned. The control system 14 may also automatically assign the electric vehicles 12 to productive tasks such that slope of terrain of the mine site and downhill regenerative recharging of the electric vehicles 12 are accounted for in calculating estimated recharge time of the electric vehicles 12. Consumption of energy from the battery system may also be accounted for by the control system 14. Assignment of the electric vehicles 12 to productive tasks may include optimisation of a speed target of each electric vehicle 12 based on energy use. The control system 14 may vary the speed target of an electrical vehicle 12 over a route.

[0056] The control system 14 may automatically assign the electric vehicles 12 to productive tasks to maximise productivity of the system 10. Each electric vehicle 12 may be provided with a battery control module, with machine charge telemetry 16, for reporting a charge level of the battery system of the electric vehicle 12 to the control system 14. The control system 14 may be in the form of a centralised off-board system.

[0057] In one form, the control system 14 sends an electric vehicle 12 to a recharging station based on proximity of the electric vehicle 12 relative to the recharging station in combination with the recharging station being available. The control system 14 may automatically plan a route of an electric vehicle 12 based on slope of terrain of the mine site and / or may plan a route of an electric vehicle 12 based on traffic flow of the system 10. An electric vehicle 12 may be sent to a recharging station based on charge level of the battery system of the electric vehicle 12.

[0058] The system 10 may be used for assigning tasks to battery-powered machines other than electric vehicles, assigning the battery-powered machines to productive tasks, and accounting for energy use of the battery-powered machines.

[0059] While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

[0060] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0061] List of Reference Numerals

[0062] 10 System for assigning a battery-powered vehicle

[0063] 12 Autonomous electric vehicle

[0064] 14 Off-board system / Control system 16 On-board charge telemetry unit

[0065] 18 Recharge command

[0066] 20 Charge level prediction module

[0067] 22 Assignment optimiser

[0068] 24 Charge command dispatcher

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A method of assigning electric haul vehicles, wherein the method includes the steps of assigning the electric haul vehicles to productive tasks, and accounting for energy use of the electric haul vehicles.

2. A method of assigning electric vehicles, wherein the method includes the steps of providing each of the electric vehicles with a battery system, providing each of the electric vehicles with a regenerative recharging system, arranging the regenerative recharging system to recharge the battery system as the electric vehicle travels downhill, and accounting for downhill routes in determining assignments of the electric vehicles.

3. A system for assigning electric vehicles, wherein the system includes a plurality of electric vehicles, each of the electric vehicles being provided with a battery system, each of the electric vehicles being provided with a regenerative recharging system arranged to recharge the battery system as the electric vehicle travels downhill, and a control system which is arranged to account for downhill routes in determining assignments of the electric vehicles.

4. A system as claimed in claim 3, wherein the system includes a mine site and the electric vehicles are electric haul vehicles for carting bulk material across said mine site.

5. A system as claimed in claim 4, wherein the system includes at least one charging station for charging the electric vehicles.

6. A system as claimed in claim 5, wherein the system includes a plurality of charging stations for charging the electrical vehicles.

7. A system as claimed in claim 6, wherein said control system accounts for unproductive statuses of the electric vehicles in determining assignments of the electrical vehicles to optimise productivity of the mine site.

8. A system as claimed in claim 7, wherein said control system accounts for unproductive statuses including travel of an electric vehicle to a charging station, travel of an electric vehicle from a charging station, and charging of an electrical vehicle at a charging station.

9. A system as claimed in any one of claims 3 to 8, wherein said control system automatically assigns the electric vehicles to productive tasks.

10. A system as claimed in claim 9, wherein said control system automatically assigns the electric vehicles to productive tasks such that charging of the electric vehicles is planned.

11. A system as claimed in claim 9 or claim 10, wherein said control system automatically assigns the electric vehicles to productive tasks such that slope of terrain of the mine site and downhill regenerative recharging of the electric vehicles are accounted for in calculating estimated recharge time of the electric vehicles.

12. A system as claimed in any one of claims 9 to 11, wherein said control system automatically assigns the electric vehicles to productive tasks accounting for consumption of energy from the battery system.

13. A system as claimed in any one of claims 9 to 12, wherein said control system automatically assigns the electric vehicles to productive tasks including optimisation of a speed target of each electric vehicle based on energy use.

14. A system as claimed in claim 13, wherein said control system may vary a speed target of an electrical vehicle over a route.

15. A system as claimed in any one of claims 9 to 14, wherein said control system automatically assigns the electric vehicles to productive tasks to maximise productivity of the system.

16. A system as claimed in any one of claims 3 to 15, wherein each electric vehicle is provided with a battery control module for reporting a charge level of the battery system of the electric vehicle to the control system.

17. A system as claimed in any one of claims 3 to 16, wherein the control system is a central control system.

18. A system as claimed in claim 5 or claim 6, wherein the control system sends an electric vehicle to a recharging station based on proximity of the electric vehicle relative to the recharging station in combination with the recharging station being available.

19. A system as claimed in claim 6, wherein the control system automatically plans a route of an electric vehicle based on slope of terrain of the mine site.

20. A system as claimed in claim 6, wherein the control system automatically plans a route of an electric vehicle based on traffic flow of the electric vehicles.

21. A system as claimed in claim 5 or claim 6, wherein the control system sends an electric vehicle to a recharging station based on charge level of the battery system of the electric vehicle.

22. A method of assigning battery-powered machines, wherein the method includes the steps of assigning the battery-powered machines to productive tasks, and accounting for energy use of the battery-powered machines.

23. A system of assigning a battery-powered vehicle, wherein the system includes an autonomous electric vehicle having a battery for powering a drive system of the autonomous electric vehicle, a work site having a charging station for recharging said battery, and an off-board system for issuing commands to the autonomous electric vehicle, wherein the autonomous electric vehicle includes an on-board charge telemetry unit for communicating current charge level of the battery to the off-board system, and the off-board system is arranged to issue a recharge command to the autonomous electric vehicle in response to a charge prediction that the battery will have charge below a threshold value.

24. A system as claimed in claim 23, wherein the off-board system includes a charge level prediction module, an assignment optimiser and a charge command dispatcher, wherein the charge level prediction module communicates with the assignment optimiser to predict a charge level for particular work allocated, and wherein the charge command dispatcher issues a recharge command to the autonomous electric vehicle when the predicted charge level is below a threshold value.

25. A system as claimed in claim 24, wherein the threshold value is a percentage threshold proportion of full charge.

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