SE548323C2

SE548323C2 - A system for controlling a payload from air comprising a winch

Info

Publication number: SE548323C2
Application number: SE2450974A
Authority: SE
Inventors: August Tynong; Theodor Mihel
Original assignee: Airforestry Ab
Priority date: 2024-09-30
Filing date: 2024-09-30
Publication date: 2026-05-26
Also published as: WO2026071964A1; SE2450974A1

Abstract

The present disclosure relates to a system (10) for remotely and/or autonomously controlling a payload from air, the system (10) comprising a remotely and/or autonomously controlled unmanned aerial vehicle (100), UAV, a remotely and/or autonomously controlled payload (105) comprising a winch (200), the winch (200) comprising a cable tensioner (203), a cable drive motor (300) configured to synchronously drive a first drum (201) and a second drum (202), and a cable (400) connecting the UAV (100) to the payload (105), the cable (400) having a first part (400a) connected to the UAV (100), wherein the cable (400) is configured to pass through the first drum (201) and the second drum (202) and subsequently pass through the cable tensioner (203), wherein the cable tensioner (203) is configured to maintain tension on a second part (400b) of the cable (400), wherein the first and second parts (400a, 400b) of the cable are laterally separated.

Description

[0001] (0001) The present invention relates generally to systems for remotely and/or autonomously controlling a payload from air, and specifically to such a system comprising an unmanned aerial vehicle connected by cable to a payload.

[0003] Background art

[0004] (0002) Traditionally, forestry operations concerning plants and trees, e.g., harvesting, watering, sowing, sampling, and the like, have been conducted by persons and equipment based on the ground. In earlier times, from the early twentieth century and going back to the early nineteenth century, little consideration was given to the state of the forest or to the eco-system within the forest. Logging was done on a massive scale to keep up with the demand caused by the industrial revolution and the subsequent expansion of human life at the time.

[0006] (0003) Many locations are extremely difficult to reach by land, even with the use of heavy equipment such as bulldozers, and forestry operations in such locations are expensive. Sometimes it may be desirable to perform a forestry operation without disturbing surrounding plants or trees.

[0008] (0004) Systems comprising to unmanned aerial vehicle interconnected with various remotely and/or autonomously controlled payloads, are known to perform the above tasks. However, further improvements to increase the reliability of these systems during operation in forested terrain are needed.

[0010] Summary of invention

[0011] (0005) It is therefore an object of the present disclosure to provide system for remotely and/or autonomously controlling a payload from air to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages.

[0012] (0006) This object is achieved by means of the subject matter of the independent claims of the present disclosure, wherein further aspects of the present disclosure are incorporated in the dependent claims.

[0014] (0007) According to a first aspect of the present disclosure it is provided a system for remotely and/or autonomously controlling a payload from air, the system comprising: a remotely and/or autonomously controlled unmanned aerial vehicle, UAV, a remotely and/or autonomously controlled payload comprising a winch, the winch comprising a cable tensioner, a cable drive motor configured to synchronously drive a first drum and a second drum, and a cable connecting the UAV to the payload, the cable having a first part connected to the UAV, wherein the cable is configured to pass through the first drum and the second drum and subsequently pass through the cable tensioner, wherein the cable tensioner is configured to maintain tension on a second part of the cable, wherein the first and second parts of the cable are laterally separated.

[0016] (0008) By configuring the system such that the cable connecting the UAV to the payload is configured to be tensioned at its second part, the cable can only be protracted or retracted when a load is applied, thus avoiding any risks of entanglement of the cable outside of winch. Thereby, an increase reliability of the system during operation is achieved.

[0018] (0009) In various embodiments of the present disclosure the cable tensioner comprises a first wheel and a second wheel for the cable to pass through, and a cable tensioning motor arranged to drive the first wheel and/or second wheel to provide tension on the second part of the cable.

[0020] (0010) The advantage of these embodiments is that an effective arrangement to provide tension on the second part of the cable is provided.

[0022] (0011) In various example embodiments the cable tensioning motor may be configured to operate such that the tension on the second part of the cable is maintained constant during a lifting operation and a lowering operation.

[0023] (0012) The advantage of these embodiments is that a reliable arrangement to maintain tension on the second part is provided.

[0025] (0013) In various example embodiments of the present disclosure the cable tensioning motor may be communicatively connected to the cable drive motor.

[0027] (0014) The advantage of these embodiments is that the arrangement is that tension on the second part of the cable is maintained in an energy efficient manner.

[0029] (0015) In various example embodiments of the present disclosure the cable tensioning motor may be arranged to drive the first wheel and wherein the second wheel may be passively driven.

[0031] (0016) The advantage of these embodiments is that the cable is guided in an effective manner.

[0033] (0017) In various example embodiments of the present disclosure the winch may comprise a drive belt arranged such that the cable drive motor can synchronously drive the drums.

[0035] (0018) The advantage of these embodiments is that an economical arrangement to drive the winch is provided.

[0037] (0019) In various example embodiments of the present disclosure the cable drive motor may comprise a first motor configured to drive the first drum and a second motor configured to drive second drum, wherein the motors are synchronously driven.

[0039] (0020) The advantage of these embodiments is the winch achieves increased modularity.

[0041] (0021) In various example embodiments of the present disclosure the system may further comprise a cable receiving device to receive a slack part of the cable having passed through the cable tensioner.

[0042] (0022) The advantage of these embodiments is that no loose part of the cable is interfering at any point during operation.

[0044] (0023) In various example embodiments of the present disclosure the cable receiving device may comprise a cable receiving basket.

[0046] (0024) The advantage of these embodiments is a that no loose part of the cable is interfering at any point during operation.

[0048] (0025) In various example embodiments of the present wherein the cable may be configured to be at least partially wound about the first drum and the second drum a predetermined number of windings.

[0050] (0026) The advantage of these embodiments is that the winch may be adjusted to various payloads.

[0052] (0027) In various example embodiments of the present disclosure the predetermined number of windings may be 2-5, preferably 3.

[0054] (0028) The advantage of these embodiments is that the winch may be adjusted to various payloads.

[0056] (0029) In various example embodiments of the present disclosure the payload may comprise a plurality of winches, preferably three winches.

[0058] (0030) The advantage of these embodiments is that loads of the system may distributed in an improved manner.

[0060] (0031) In various example embodiments, the payload may be a remotely and/or autonomously controlled harvesting tool.

[0062] (0032) The advantage of these embodiments is that the system may efficiently harvest trees from air in a remote and/or autonomous manner.

[0064] (0033) Further advantages with and features of the invention will be apparent from the following detailed description of preferred embodiments.

[0065] (0034) A more complete understanding of the abovementioned and other features and advantages of the present invention will be apparent from the following detailed description of preferred embodiments in conjunction with the appended drawings, wherein:

[0067] Figure 1 depicts a schematic illustration of a system for remotely and/or autonomously controlling a payload from air according to various example embodiments of the present disclosure.

[0069] Figure 2 depicts an isometric view of a winch according to various example embodiments of the present disclosure.

[0071] Figure 3 depicts an isometric view of a winch according to various example embodiments of the present disclosure.

[0073] Figure 4 depicts a schematic view of a system 10 for remotely and/or autonomously controlling a payload from air according to various example embodiments of the present disclosure during a lifting operation.

[0075] Figure 5 depicts a schematic view of a system 10 for remotely and/or autonomously controlling a payload from air according to various example embodiments of the present disclosure during a lowering operation.

[0077] Description of embodiments

[0078] (0035) The invention is not limited only to the embodiments described above and shown in the drawings, which primarily have an illustrative and exemplifying purpose. This patent application is intended to cover all adjustments and variants of the preferred embodiments described herein; thus, the present invention is defined by the wording of the appended claims and the equivalents thereof. Thus, the apparatus and system may be modified in all kinds of ways within the scope of the appended claims.

[0079] (0036) Figure 1 depicts a schematic illustration of a system 10 for remotely and/or autonomously controlling a payload from air according to various example embodiments of the present disclosure. The system 10 may comprise a remotely and/or autonomously controlled unmanned aerial vehicle, UAV, 100. The UAV 100 can be considered as a forestry forwarder. The system 10 may further comprise a remotely and/or autonomously controlled payload 150. In all example embodiments, the payload 150 may be any forestry tool used for various forestry operations which may be carried be said UAV 100. In various example embodiments the payload 150 may be a remotely controlled harvesting tool 150. In various example embodiments the payload 150 may be an autonomously controlled harvesting tool 150. In various example embodiments the payload 150 may be a remotely and autonomously controlled harvesting tool. The harvesting tool 150 may be provided with means for delimbing, cutting and holding a tree, or combinations thereof. In various example embodiments the payload 150 may comprise means for at least watering, sowing, sampling, or to delivering a parcel from air, or combinations thereof.

[0081] (0037) In figure 1, said UAV 100 is carrying said remotely and/or autonomously payload 150 on its way to perform a forestry operation, here depicted as harvesting at least a portion of a tree 135, e.g. in a forest. The UAV 100 may be remotely controlled by a base station 120 and/or autonomously controlled and optionally communicating with base station 120. The base station 120 may be a stationary unit or a mobile unit. The base station 120 may, when remotely controlled, be operated by at least one human being, whereas, when autonomously controlled, be a base station 120 with programmed software algorithms used for supporting the autonomous UAV and/or the means configured for harvesting at least a portion of a tree. The base station 120 may be a stationary unit or a mobile unit.

[0083] (0038) An autonomous payload 150 configured for harvesting at least a portion of a tree said means is able to operate without being controlled directly by humans whereas in a remotely controlled payload 150 is able to be operated from a remote distance controlled directly by humans. In various example embodiment said payload 150 and said UAV 100 are remotely controlled. In various example embodiment said payload 150 and said UAV 100 are autonomously controlled. In various example embodiments said payload 150 is remotely controlled and said UAV 100 is autonomously controlled. In various example embodiments said payload 150 is autonomously controlled and said UAV 100 is remotely controlled.

[0084] (0039) The UAV 100 and the autonomously and/or remotely controlled payload 150 may be communicating with each other via one or more of WiFi, Bluetooth, radio communication, telecommunication (3G, 4G, 5G), optical fibre and/or electrical wire. Depending on the distance and/or communication quality between the UAV 100 and/or the autonomously and/or remotely controlled payload 150 the communication may change from one type of communication to another.

[0086] (0040) The autonomously and/or remotely controlled payload 150 may comprise various means for harvesting and/or delimbing a tree. In various example embodiments said the payload 150 may be configured for gripping/attaching itself to the trunk of the tree and/or for moving up and down along the trunk of the tree, e.g., the movement may be performed by at least one electrically driven wheel travelling on said tree trunk. In various example embodiments at least one wheel may be electrically driven for enabling movement up and down said tree trunk and at least one other wheel is arranged for friction reduction during said movement. In various example embodiments at least to wheels are configured to attach, secure and move said means configured to harvesting at least a portion of a tree.

[0087] Delimbing may be performed by one or a plurality of cutting means, snapping means, and/or shearing means. The cutting means may be by cutting chains and/or by rotary cutting disks. The cutting may be performed by a straight movement along said trunk of said means configured for harvesting at least a portion of a tree and/or by a serpentine movement along the trunk by said means configured for harvesting at least a portion of a tree.

[0089] (0041) In various example embodiments the UAV 100 may comprise a power unit (not shown) for powering said UAV 100 and payload 150. The power from said power unit in said UAV 100 may be delivered to the payload 150 via at least one power cable (not shown). The power unit may be an electric motor and/or an internal combustion engine (not shown). In various example embodiments said UAV 150 may comprise at least a first power unit for powering said UAV 100 and the payload 150 may comprise at least a second power unit for powering the payload. The power unit in said UAV 100 may be electrical and/or an internal combustion engine. The power unit the payload 150 may be electrical and/or an internal combustion engine.

[0091] (0042) Turning back to figure 1, the system 10 may comprise a cable 400 connecting the UAV 100 to the payload 150. The payload 150 may further comprise a winch 200. The winch 200 enables the payload 150 to lowered relative to the UAV 100 during operation by retraction or extension of the cable 400. The cable 400 may be a spectra or Dyneema cord, a Kevlar cable, or a stainless steel wire rope, or the like.

[0093] (0043) Figure 1 only serves as schematic of the systems 10 described herein. As such, details of the winch 200 will be described in relation to figures 2 and 3 below. In various example embodiments the payload 150 may comprise a plurality of winches 200, e.g., three winches 200. Each winch 200 may also be known as a capstan winch.

[0095] (0044) Turning now to figure 2, an isometric view of a winch 200 according to various example embodiments of the present disclosure is depicted. As mentioned, the payload 150 may comprise the winch 200. In other words, the winch 200 may be arranged on the payload 150. The winch 200 described herein relies on friction between parts of the winch 200 and the cable 400, as will be elucidated throughout the present disclosure. In other words, the winch 200 may also be known as a capstan or a capstan winch.

[0097] (0045) Figure 2 depicts a winch 200 comprising a first drum 201 and a second drum 202 which the cable 400 is configured to pass through. In figure 2, the passing through of cable 400 in regard to the first drum 201 and second drum 202 is depicted as follows. First, the cable 400 extends from the UAV 100 (the UAV 100 is in itself not shown in figure 2) and is wound least partially around the first drum 201. Subsequently, the cable 400 passes on to be partially wound around the second drum 202. Further subsequently, the cable 400 yet again passes on and is wound partially around the first drum 201. Finally, the cable 400 passes towards the cable tensioner 203, in other words the cable 400 has now passed through the drum arrangement of the first drum 201 and the second drum 202. The described manner of which the cable 400 passes through the first drum 201 and the second drum 202 is interpreted in this context as one winding.

[0099] (0046) In various example embodiments, the cable 400 is configured to be wound about the first drum 201 and the second drum 202 a predetermined number of windings. In other words, it follows that the cable 400, could be wound around the first drum 201 and second drum 202 another time before passing through towards the cable tensioner 203. Principally, an increased number of windings cause further frictional forces of the winch 200, which may be suitable depending on the weight of the payloads 150 and/or the number of winches 200 used in the systems 10 described herein.

[0101] (0047) The weight of the payload 150 may be up to 300 kg, but may be several hundreds of kg. However, the number of windings may also depend on the relative distances between the first drum 201 and the second drum 202. A longer distance between the first drum 201 and second drum 202 increases the length the cable 400 passing through the drums 201, 202. It should be appreciated the skilled person may consider combinations of relative distances between the drums 201, 202 and the number of windings according to needs. It should also be appreciated that the windings are predetermined - during operation of the winch, the number of windings around the first drum 201 and a second drum 202 stay constant.

[0102] Further, the diameter of each drum 201, 202 may be the same or different. In principle a higher drum diameter increases the frictional force of the cable 400 passing through the drums 201, 202.

[0104] (0048) The first drum 201 and the second drum 202 may in various example embodiments be provided with flanges to ensure even winding in-case of a plurality of predetermined windings. The flanges may for example be a thread with a predetermined pitch. This may ensure no windings of the cable 400 stack on top of each other. In figure 2, the first drum 201 is illustrated with flanges, whereas the second drum 202 is not. However, this should be appreciated as an example embodiment, and both drums 201, 202 may comprise flanges, or neither. It is appreciated that more complex arrangements with several more drums, e.g. a third drum (not shown) may operate under the same principles as illustrated herein.

[0106] (0049) As seen further in figure 2, the winch 200 may comprise a cable drive motor 300. The cable drive motor 300 may e.g. comprise a suitable motor, e.g. an electrical motor. The cable drive motor 300 may be configured to synchronously drive a first drum 201 and a second drum 202. There are various example embodiments for synchronously driving the drums 201, 202. As illustrated in figure 2, the winch 200 may e.g., comprise a drive belt 303 arranged such that the cable drive motor 300 can synchronously drive the drums 201, 202. It may also be possible that the drums 201, 202 may be synchronously driven via a gearing mechanism. It follows that only one of the drums 201, 202 is drivably connected to the cable drive motor an output shaft of a motor of the cable drive motor 300, whereas the other drum is driven indirectly via the drive belt 303. In figure, the first drum 201 is shown to be driven directly by the cable drive motor 300 while the second drum 202 is indirectly driven via the drive belt 303, but the relationship could be vice versa.

[0108] (0050) Turning to figure 3, in an example embodiment the cable drive motor 300 may comprise a first motor 301 configured to drive the first drum 201 and a second motor 302 configured to drive second drum 202, and wherein the motors 301, 302 may be synchronously driven. For these embodiments, the first motor 301 and the second motor 303 may be communicating with each other via one or more of WiFi, Bluetooth, radio communication, telecommunication (3G, 4G, 5G), optical fibre and/or electrical wire.

[0110] (0051) As seen in figures 2 and 3, in various example embodiments, the winch 200 may further comprise a cable receiving device 500 to receive a slack part 400c of the cable 400 having passed through the cable tensioner 203. In various example embodiments, wherein the cable receiving device 500 comprises a cable receiving basket. The slack part 400c of the cable 400 may therefore self-organize within the cable receiving device, e.g. the cable receiving basket. A cable receiving basket may be a suitable metal container attached to the payload 150 or the winch 200. In various example embodiments the cable receiving device 500 comprises a cable receiving drum (not shown). In such embodiments, there is no loose slack part 400c of the cable 400. It is appreciated that if a cable receiving drum is used, it is optional to also provide a cable receiving basket for further protection of the cable. In various example embodiments the cable receiving basket may be configured as a basket shape (i.e., cuboid), i.e., with an opening area as large as its bottom base area.

[0112] (0052) In various example embodiments, the cable receiving basket may be shaped triangularly, or frustoconically such that the opening area of the basket is smaller than the base area. Such basket shapes may improve self-organizing of the cable 400 within the cable receiving basket.

[0114] (0053) Furthermore, the winch 200 may comprise a cable tensioner 203. As understood from following the extension of the cable 400 through the drums 201, 202 as explained above, the cable 400 having passed through said drums 201, 202 subsequently pass through the cable tensioner 203. The cable tensioner 203 may be configured to maintain tension on a second part 400b of the cable 400, wherein the first and second parts 400a, 400b of the cable are laterally separated. In other words, the first and second parts 400a, 400b of the cable are distinct parts of the cable 400.

[0116] (0054) Generally, the cable tensioner 203 may be configured to, during a lifting operation, actively or passively provide a small braking force relative to the drive of the drums 201, 202 such as the cable 400 may be slowed down.

[0118] (0055) In various example embodiments, such as shown in figure 2, the cable tensioner 203 may comprise a first wheel 204 and a second wheel 205 and a cable tensioning motor 206. Each wheel 204, 205 may be provided with teeth. One example is shown in figure 2, the first wheel 204 is illustrated with teeth whereas the second wheel 205 is provided with a guide track and no teeth.

[0120] (0056) In various example embodiments it is also possible that the cable tensioner 203 may be passively driven by the cable drive motor 300 via a drive belt (not shown) drivingly connecting the cable tensioner 203 and the cable drive motor 300.

[0122] (0057) In various example embodiments, the cable tensioner 203 may comprise a cable tensioning motor 206. The cable tensioning motor 206 may be any suitable motor, e.g. an electrical motor and may be arranged to drive the first wheel 204 and/or second wheel 205. In figure 2, the first wheel 204 is illustrated to be driven by the cable tensioning motor 204, whereas the second wheel is passive and serves as a cable guide. As the cable 400 passing through the first wheel 204 and/or second wheel 205, tension on the second part 400b of the cable 400 may be provided and maintained by operation of the cable tensioning motor 206.

[0124] (0058) It is however possible that the cable tensioner 203 may be a purely passive arrangement with no motor. E.g. the cable tensioner 203 may comprise a passive drum (not shown) for winding of the cable 400 that is spring loaded to provide tension on the second part 400b of the cable 400. Further, the cable 400 may slide slightly when passing through the drums 201, 202 compared to the cable tensioner 203.

[0126] (0059) The cable tensioner 203 may be provided with a measuring device, such as an encoder or the like, to measure the retraction/protraction of the cable 400 more reliably. In such embodiments, the cable tensioner 203 may provide an indication of the length of a tree.

[0128] (0060) In various example wherein a drive tensioning motor 206 is present, the cable tensioning motor 206 and the cable drive motor 300 may be communicating with each other via one or more of WiFi, Bluetooth, radio communication, telecommunication (3G, 4G, 5G), optical fibre and/or electrical wire. The cable tensioning motor 206 and the cable drive motor 300 may adopt a “master-slave” relationship as known in the art, wherein the cable drive motor 300 may be configured as the master drive. It is important to note that the cable drive motor 300 may be adapted to provide sufficient force to retract and protract the cable 400 such that the payload 150 can be lowered or lifted. The cable tensioning motor may provide tension to a second part 400b of the cable 400. In various example embodiments, the cable tensioning motor 206 may be configured to operate such that the tension on the second part 400b of the cable 400 is maintained constant during a lifting operation and a lowering operation.

[0130] (0061) In various example embodiments, the cable tensioning motor 206 may arranged to operate at a higher speed than an operating speed of the cable drive motor 300. This provides excellent cable tension to the second part 400b of the cable 400. If dual synchronous motors are used in the cable drive motor 300, the sample principle applies. The various speed information of each motor/cable drive motor may be communicated via the means described herein. It is appreciated that each motor or cable drive motor mentioned may reversible such that the winch can retract or protract the cable 400 and thereby lower or lift the payload 150.

[0132] (0062) Figure 4 depicts a system 10 for remotely and/or autonomously controlling payload from air according to various example embodiments of the present disclosure in a lifting operation. In other words, a payload 150 is lifted towards a UAV 100 by retracting a cable 400 using a winch 200 as described herein. In contrast figure 5 depicts a system 10 for remotely and/or autonomously controlling a payload 150 from air according to various example embodiments of the present disclosure in a lowering operation. In other words, a payload 150 is lowered away from a UAV 100 by retracting a cable 400 using a winch 200 as described herein. Any constructional detail of the winch 200 described above and will not be repeated here.

[0134] (0063) During a lifting operation the cable drive motor 300 may operate in a reverse direction compared to a lowering operation. This may be done by reversal of e.g. at least one motor of the cable drive motor 300. It should be appreciated the force required to perform a lifting operation is larger than the force required to perform a lowering operation to the weight of the payload (e.g. 40-80kg) and gravity. For example, in embodiments wherein a cable tensioning motor 206 is present said cable tensioning motor 206 may be configured to operate at a lower speed during a lifting operation. Consequently, the cable tensioning motor 206 may be configured to operate at a higher speed during a lowering operation or to operate at a higher speed during a lowering operation. The various speed information of each motor/cable drive motor may be communicated via the means described herein, such that the cable tensioning motor 206 always applies a speed that is necessary to maintain tension on the second part 400b of the cable 400 regardless of the operation.

[0136] (0064) It is appreciated that during operation some part of the length of the cable 400 may generally be a distance between the payload 150 and the UAV 100, whereas the rest of the length of cable 400 is situated the winch arrangement and as a slack part 400c. E.g., if the cable 400 has a length of 10 meters and the distance the payload 150 and the UAV 100 is 3 meters, then it follows those 7 meters of the cable length 400 is situated in the winch 200, where a proportion of the cable 400 is considered the slack part 400c. In another situation, e.g. where the cable 400 has a length of 10 meters and the distance the payload 150 and the UAV 100 is 5 meters, it follows that the remaining 5 meters of the cable length is situated in the winch, where a proportion of the cable is considered the slack part 400c. In the two situations illustrated, the slack part 400c may naturally be less when the payload 150 is at a longer distance from the UAV.

[0138] (0065) The person skilled in the art realized that the present disclosure by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. It should further be noted that the drawings not necessarily are to scale, and dimensions of certain features may have been exaggerated for the sake of clarity. Emphasis is instead placed upon illustrating the principle of the embodiments herein. Additionally, in the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality.

[0140] (0066) Various examples have been described. These and other examples are within the scope of the following claims.

Claims

1. A system (10) for remotely and/or autonomously controlling a payload from the air, the system (10) comprising:

- a remotely piloted and/or autonomous unmanned aerial vehicle (100), UAV,

- a remotely controlled and/or autonomously controlled payload (150) comprising a winch (200), characterized in that the winch (200) comprises a cable tensioner (203), a cable drive motor (300) configured to synchronously drive a first drum (201) and a second drum (202), and a cable (400) connecting the UAV (100) to the payload (150), wherein the cable (400) has a first portion (400a) connected to the UAV (100), wherein the cable (400) is configured to pass through the first drum (201) and the second drum (202) and then pass through the cable tensioner (203), wherein the cable tensioner (203) is configured to maintain tension on a second portion (400b) of the cable (400) and comprises a first wheel (204) and a second wheel (205) for the cable (400) to pass through, and a cable tensioning motor (206) arranged to drive the first wheel (204) and/or the second wheel (205) to provide tension on the second portion (400b) of the cable (400), wherein the first and second portions (400a, 400b) of the cable are laterally separated.

The system (10) of claim 1, wherein the cable tension motor (206) is configured to operate such that the tension on the second portion (400b) of the cable (400) is maintained constant during a lifting operation and a lowering operation.

The system (10) of claim 1 or 2, wherein the cable tension motor (206) is communicatively connected to the cable drive motor (300).

4. The system (10) according to any one of claims 1-3, wherein the cable tensioning motor is arranged to drive the first wheel (204) and wherein the second wheel (205) is passively driven.

5. The system (10) according to any one of the preceding claims, wherein the winch (300) comprises a drive belt (303) arranged so that the cable drive motor (300) can synchronously drive the drums (201, 202).

6. The system (10) according to any one of claims 1-3, wherein the cable drive motor (300) comprises a first motor (301) configured to drive the first drum (201) and a second motor (302) configured to drive the second drum (202), wherein the motors (301, 302) are driven synchronously.

7. The system (10) according to any one of the preceding claims, further comprising a cable receiving device (S00) for receiving a slack portion (400c) of the cable (400) that has passed through the cable tensioner (203).

The system (10) of claim 7, wherein the cable receiving device (500) comprises a cable receiving basket.

The system (10) of claim 7, wherein the cable receiving device (500) comprises a cable receiving drum.

The system (10) according to any one of the preceding claims, wherein the cable (400) is configured to be at least partially wound around the first drum (201) and the second drum (202) a predetermined number of turns.

11. The system (10) according to claim 10, wherein the predetermined number of windings is 2-5, preferably 3.

12. The system (10) according to any one of the preceding claims, wherein the payload (150) comprises a plurality of winches (200), preferably three winches (200).

13. The system (10) according to any one of the preceding claims, wherein the payload (150) is a remotely controlled and/or autonomously controlled harvesting tool.