Guiding device for detecting the tension of a mooring line

Abstract

The application discloses a kind of guiding devices for detecting the tension degree of tether cable, relate to tethered unmanned aerial vehicle technical field, compact structure, high reliability, small space occupancy rate;Device is simple, strong installation adaptability, can be built-in in various ground devices, such as cable box or take-off and landing platform bottom, side direction;Avoid the uncertainty caused by manual experience adjustment motor output torque, can realize real-time monitoring cable tension condition, and provide reliable basis for autonomous dynamic adjustment cable tension degree.It avoids part of manual operation under special extreme weather, improves flight guarantee and safety.

Description

Technical Field

[0001] This invention relates to the field of tethered unmanned aerial vehicle (UAV) technology, and in particular to a guide device for detecting the tension of tethered cables. Background Technology

[0002] Tethered drones mainly consist of the drone, a power supply box, and a cable box. The drone communicates with the ground via a tethered cable. Currently, the cable delivery is not fully autonomously controllable. Often, cable tension is only determined by visually observing the cable's trajectory in the air during the drone's launch and retrieval phases. The motor's output torque is then manually adjusted to control the cable's release and retraction speed, thus regulating cable tension or slack. Therefore, significant uncertainties and potential safety issues remain during drone flight.

[0003] The existing technology mainly has the following technical problems:

[0004] 1. During the launch and recovery phases of the drone, if the cable is too slack and touches the ground or causes significant horizontal drag, it is possible to promptly identify and manually adjust the cable release and retrieval speed to tighten the cable. However, when the cable is tightened, the change in curvature is often difficult to define, and manual intervention may result in errors that could damage the optical fibers inside the cable.

[0005] 2. During the hovering phase of a drone, the motor output torque is usually preset. If strong winds are encountered and the cable tension exceeds the motor's preset value, the cable will be continuously pulled out, causing it to swing arbitrarily and creating uncontrollable safety issues.

[0006] 3. Due to force majeure factors, such as weather (smog, strong winds), it is impossible to clearly observe the cable outlet by the naked eye. In this case, it is impossible to manually adjust the cable tension. Summary of the Invention

[0007] In view of the above problems, the present invention provides a guide device for detecting the tension of a mooring cable to overcome or at least partially solve the above problems.

[0008] This invention provides the following solution:

[0009] A guide device for detecting the tension of a mooring cable, comprising:

[0010] The guiding mechanism includes a first guide roller, a second guide roller, a third guide roller, and a fourth guide roller, each of which is connected to two side plates. The outer ends of the first guide roller, the second guide roller, and the third guide roller each form a first guide surface with an arc. A channel for cable passage is formed between the first guide surface and the second guide surface.

[0011] A clamping mechanism includes a clamping roller and two linear guide rails. The two linear guide rails are horizontally arranged and connected to the two side plates in a one-to-one correspondence. The two ends of the clamping roller are respectively connected to the two linear guide rails through linear guide rail adapter blocks, so that the clamping roller can slide horizontally along the two linear guide rails. The fourth guide roller and the outer end face arc of the clamping roller form a second guide surface.

[0012] Two tension detection mechanisms are provided, each including a spring and a tension sensor. The tension sensor is connected to a sensor fixing block on the side plate. One end of the spring is connected to a non-rotatable part of the pressure roller, and the other end of the spring is connected to a spring fixing block on the side plate and cooperates with the sensitive element of the tension sensor so that the tension sensor changes its output value as the length of the spring changes.

[0013] The controller is communicatively connected to the tension sensor; the controller is used to control the cable retractor to change its working state when it is determined that the sensor output value is not within the target value range, so that the sensor output value returns to the target value range.

[0014] Preferably, the first guide roller, the second guide roller, the third guide roller, and the fourth guide roller all include the same first guide shaft and a first roller that is wrapped around the first guide shaft and can rotate around the first guide shaft; the two ends of each of the first guide shafts are respectively connected to the two side plates.

[0015] Preferably, the system further includes a set of guide wheels, which consists of two guide wheels arranged vertically and connected to the corresponding side plate via a connecting rod.

[0016] Preferably, the stop wheel includes a second guide shaft and a second roller that is wrapped around the second guide shaft and can rotate around the second guide shaft.

[0017] Preferably, the clamping mechanism further includes a fixing rod, the two ends of which are respectively connected to the two linear guide transition blocks.

[0018] Preferably, the pressing roller includes a third guide shaft and a third roller that is wrapped around the third guide shaft and can rotate about the third guide shaft.

[0019] Preferably, one end of the spring is connected to the mounting hole on the third guide shaft.

[0020] Preferably: the controller is used to control the cable retractor to change its operating state when it determines that the sensor output value is not within the target value range, including:

[0021] When the sensor output value is determined to be outside the target value range, the output torque and / or take-up speed of the cable take-up and take-up motor are controlled to bring the sensor output value back to the target value range.

[0022] Preferably: when the sensor output value is determined to be less than the minimum value of the target value range, the control cable rewind / unwind motor is adjusted to increase the motor output torque;

[0023] When the sensor output value exceeds the maximum value of the target value range, the control cable rewind motor is adjusted to reduce the motor output torque.

[0024] Preferably: when the UAV is in recovery mode, and the sensor output value is less than the minimum value of the target value range, the cable take-up and take-off motor is controlled to increase the take-up speed; when the sensor output value exceeds the maximum value of the target value range, the cable take-up and take-off motor is controlled to increase the motor output torque.

[0025] When the drone is determined to be in a hovering state, and the output value of the sensor exceeds the maximum value of the target value range, the control cable retractor increases the output torque of the motor so that the output cable length of the encoder installed at the transmission mechanism remains unchanged.

[0026] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0027] This application provides a guiding device for detecting the tension of tethered cables. It features a compact structure, high reliability, and small space occupation. The device is simple to use and highly adaptable to installation, and can be integrated into various ground devices, such as cable boxes or the bottom and side of takeoff and landing platforms. It avoids the uncertainty caused by manually adjusting the motor output torque based on experience, enabling real-time monitoring of cable tension and providing a reliable basis for autonomous dynamic adjustment of cable tension. This eliminates some manual operations under extreme weather conditions, improving flight assurance and safety.

[0028] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of a guide device for detecting the tension of a mooring cable according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the guiding mechanism provided in an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the pressing mechanism provided in an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the tension detection mechanism provided in an embodiment of the present invention;

[0034] Figure 5 This is a force analysis diagram of the tension sensor provided in an embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of the structure of a spring in a compressed state under the action of preload, provided in an embodiment of the present invention;

[0036] Figure 7 This is a schematic diagram of the structure of a spring in an extended state under tension, provided in an embodiment of the present invention;

[0037] Figure 8 This is a schematic diagram of the spring state when the sensor output value is within the target value range, as provided in an embodiment of the present invention.

[0038] In the diagram: guide mechanism 1, first guide roller 11, second guide roller 12, third guide roller 13, fourth guide roller 14, first guide shaft 105, first roller 106, pressing mechanism 2, pressing roller 21, linear guide rail 22, linear guide rail adapter block 23, fixing rod 24, third guide shaft 205, third roller 206, tension detection mechanism 3, spring 31, tension sensor 32, sensor fixing block 33, spring fixing block 34, stop wheel 4, second guide shaft 401, second roller 402, connecting rod 41, side plate 5, cable 6. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0040] See Figure 1 This invention provides a guiding device for detecting the tension of a mooring cable, as exemplified by an embodiment of the present invention. Figure 1 As shown, the device may include:

[0041] The guiding mechanism 1 includes a first guide roller 11, a second guide roller 12, a third guide roller 13, and a fourth guide roller 14, all of which are connected to the two side plates 5. The outer ends of the first guide roller 11, the second guide roller 12, and the third guide roller 13 are arc-shaped to form a first guide surface. A channel for the cable 6 to pass through is formed between the first guide surface and the second guide surface.

[0042] The clamping mechanism 2 includes a clamping roller 21 and two linear guide rails 22. The two linear guide rails 22 are horizontally arranged and connected to the two side plates 5 respectively. The two ends of the clamping roller 21 are respectively connected to the two linear guide rails 22 through linear guide rail adapter blocks 23, so that the clamping roller 21 can slide along the two linear guide rails 22 in the horizontal direction. The fourth guide roller 14 and the outer end face arc of the clamping roller 21 form a second guide surface.

[0043] Two tension detection mechanisms 3 are provided, each including a spring 31 and a tension sensor 32. The tension sensor 32 is connected to a sensor fixing block 33 on the side plate 5. One end of the spring 31 is connected to the non-rotatable part (third guide shaft 205) of the pressure roller 21, and the other end of the spring 31 is connected to a spring fixing block 34 on the side plate 5 and is connected to the sensitive element of the tension sensor 32 so that the tension sensor 32 changes its sensor output value as the length of the spring 31 changes.

[0044] The controller is communicatively connected to the tension sensor 32; the controller is used to control the cable retractor to change its working state when it is determined that the sensor output value is not within the target value range, so that the sensor output value returns to the target value range.

[0045] The guiding device for detecting the tension of tethered cables provided in this application embodiment can determine the cable tension and, in conjunction with the flight altitude data returned by the UAV and the cable extension length, more reliably adjust the retrieval and release of the tethered cable. Simultaneously, it has a simple and compact structure, is easy to assemble and disassemble, occupies little space, and requires no major modifications to ground equipment; it can be combined with control to achieve automatic cable adjustment, eliminating the need for manual intervention in extreme and harsh environments, thus ensuring greater flight safety. Furthermore, it has strong adaptability and can be adapted to different tethered cable extension methods.

[0046] The guiding mechanism 1 provided in this application embodiment is used to guide the cable winding and unwinding. In order to improve the smoothness of winding and unwinding, a rotatable guide roller is used for guidance. In order to facilitate the installation of the guide roller, this application embodiment can provide that the first guide roller 11, the second guide roller 12, the third guide roller 13 and the fourth guide roller 14 each include a first guide shaft 105 and a first roller 106 wrapped around the first guide shaft 105 and rotatable around the first guide shaft 105; the two ends of each of the first guide shafts 105 are respectively connected to the two side plates 5.

[0047] To prevent cable clamping between the guide rollers and the side plate 5 during the reciprocating motion of the cable exit, this embodiment of the application may also provide a baffle wheel assembly, which includes two baffle wheels 4, which are arranged vertically and connected to the corresponding side plate 5 through a connecting rod 41.

[0048] Furthermore, the guide wheel 4 includes a second guide shaft 401 and a second roller 402 that is wrapped around the second guide shaft 401 and can rotate around the second guide shaft 401.

[0049] The clamping mechanism 2 provided in this embodiment can move horizontally along the guide rail under the force of the cable, thereby transferring the force on the cable to the tension sensor 32 and realizing the detection of cable tension. To avoid a large difference in displacement between the two linear guide rails 22 during the horizontal reciprocating motion of the cable, which would affect the numerical recording deviation of the tension sensor 32, this embodiment can provide the clamping mechanism 2 further including a fixing rod 24, with each end of the fixing rod 24 connected to one of the two linear guide rail adapter blocks 23.

[0050] Furthermore, the pressing roller 21 includes a third guide shaft 205 and a third roller 206 that is wrapped around the third guide shaft 205 and can rotate around the third guide shaft 205.

[0051] To facilitate the installation and connection of the spring 31 and the pressure roller 21, this embodiment of the application can provide that one end of the spring 31 is connected to the mounting hole on the third guide shaft 205.

[0052] The controller provided in this application embodiment can control the cable retractor based on the obtained sensor output value and the working scenario of the tethered drone, so as to keep the sensor output value within the target value range, and thus keep the cable tension within a certain range.

[0053] In a specific implementation, embodiments of this application may provide that the controller, when determining that the sensor output value is not within the target value range, controls the cable retractor to change its operating state, including:

[0054] When the sensor output value is determined to be outside the target value range, the output torque and / or take-up speed of the cable take-up and take-up motor are controlled to bring the sensor output value back to the target value range.

[0055] Furthermore, when the sensor output value is determined to be less than the minimum value of the target value range, the control cable rewind motor is adjusted to increase the motor output torque;

[0056] When the sensor output value exceeds the maximum value of the target value range, the control cable rewind motor is adjusted to reduce the motor output torque.

[0057] To improve the accuracy of the adjustment, the cable take-up and drop-off motor can be adjusted according to different actual application scenarios. For example, in one implementation, this embodiment can provide the following: when the UAV is in the recovery state and the sensor output value is less than the minimum value of the target value range, the cable take-up and drop-off motor can be controlled to increase the take-up speed; when the sensor output value exceeds the maximum value of the target value range, the cable take-up and drop-off motor can be controlled to increase the motor output torque.

[0058] When the drone is determined to be in a hovering state, and the output value of the sensor exceeds the maximum value of the target value range, the control cable retractor increases the output torque of the motor so that the output cable length of the encoder installed at the transmission mechanism remains unchanged.

[0059] The following is a detailed description of the specific structure and usage of the guide device for detecting the tension of tethered cables provided in the embodiments of this application.

[0060] The guiding device for detecting the tension of a tethered cable provided in this application includes a guiding mechanism 1, a pressing mechanism 2, and a detection mechanism 3.

[0061] like Figure 2 As shown, the guide mechanism 1 provided in this application embodiment includes four rollable guide rollers: a first guide roller 11, a second guide roller 12, a third guide roller 13, and a fourth guide roller 14. Each guide roller consists of a first guide shaft 105 fixed to the side plates 5 at both ends and a first roller 106 that wraps around the first guide shaft 105.

[0062] To prevent cable jamming between the guide roller and side plate 5 during the reciprocating motion of the cable exiting the circuit, a set of guide rollers is vertically fixed to the side plate 5. Each guide roller 4 in the set consists of a second guide shaft 401, a second roller 402 surrounding the second guide shaft 401, and a connecting rod 41. There are gaps between the second guide shaft 401 and the second roller 402, and between the first guide shaft 105 and the first roller 106, to ensure that the first roller 106 can roll freely.

[0063] The cable passes through a second guide surface formed by the outer arc of the first guide roller 11, the second guide roller 12, and the third guide roller 13, and the outer arc of the fourth guide roller 14 and the pressure roller 21. The first guide roller 11, the second guide roller 12, and the third guide roller 13 restrict the approximate path of the cable 6 when it exits the cable, and the fourth guide roller 14 can, to some extent, prevent the cable from sagging if it is too slack, thus avoiding damage caused by friction between the cable and other equipment.

[0064] like Figure 3 As shown, the clamping mechanism 2 mainly consists of a clamping roller 21 and a linear guide rail 22 that provides horizontal movement. The third guide shaft 205 and the third roller 206 wrapped around it together form the clamping roller 21. The clamping roller 21 is fixed to the linear guide rail 22 via a linear guide rail adapter block 23 and can move horizontally according to the tension provided when the cable 6 is tensioned, the tension provided when the spring 31 extends or contracts, or the preload. A gap exists between the third guide shaft 205 and the third roller 206 to ensure that the third roller 206 can roll freely. The linear guide rail 22 restricts the movement trajectory of the clamping roller 21 in the horizontal direction, ensuring that the value detected by the tension sensor 32 is always horizontal, thus improving reliability. The fixing rod 24 can fix the linear guide rails 22 on both sides to move simultaneously, preventing a large difference in displacement between the two linear guide rails 22 during horizontal reciprocating motion of the cable, which would affect the value recording deviation of the tension sensor 32.

[0065] like Figure 4 As shown, the detection mechanism consists of a spring 31 and a tension sensor 32. One end of the spring 31 is connected to the side through hole of the third guide shaft 205 to synchronously sense the movement of the pressure roller 21. The other end is connected to the tension sensor 32 through a spring fixing block 34 fixed on the side plate 5. The tension sensor 32 is fixed to the side plate 5 through a sensor fixing block 33.

[0066] The controller can be set up independently or integrated into the control board of the electrical box inside the cable box.

[0067] When the system is in use, at the pressure roller 21 ( Figure 5 Perform stress analysis on the isolated cable (with the dashed box in the middle) as follows: Figure 5 As shown, when the cable tension is at a reasonable level, it should be simultaneously subjected to the spring force Fspring provided by the spring 31 during tension in the horizontal direction, and the horizontal component of the tension force (aircraft and wind resistance) on the cable, Ftension. These two forces should maintain dynamic balance, such as... Figure 8 As shown in the diagram, the sensor output value will remain within a certain stable fluctuation range.

[0068] During the drone launch and recovery phases, if the cable is in a relaxed state, the spring 31 will be in a compressed state under the preload, and the cable will be pulled to [a certain position] by the pressure roller 21. Figure 6 In the indicated state, the tension sensor 32 will send a signal to the control system because it detects zero tension, automatically increasing the motor output torque by a certain ratio to keep the sensor output value within a certain range. If the cable is too taut, it will straighten under the tension, pulling the pressure roller 21 to... Figure 7 In the indicated state, the tension sensor 32 will detect a tension value exceeding the normal tension range. After sending a signal to the control system, it will automatically reduce the motor output torque according to a certain ratio. After adjustment, the spring 31 will return to its original position. Figure 8 The state shown.

[0069] In special circumstances, during drone recovery, the drone may descend to an altitude greater than the cable length required for retrieval. At high altitudes, it can be difficult to determine the cable tension. The tension detection mechanism 3 automatically increases the retrieval speed if the sensor output value is below the normal fluctuation range. Conversely, if the sensor output value exceeds the normal fluctuation range, combined with the cable length and the drone's return altitude, it indicates strong winds during descent. In this case, the motor output torque should also be increased until the sensor value is within the normal fluctuation range. The tension detection mechanism 3 ensures that the motor output torque is not adjusted blindly, providing a correct fluctuation range after adjustment, allowing the cable to maintain normal tension at all times and preventing dangerous cable swings.

[0070] During the drone's hovering phase, once the aircraft's return altitude information is determined, if strong winds are encountered, the cable will become taut due to wind resistance. At this time, the tension sensor 32 will output a larger value and return it to the control system. With the aircraft's altitude information determined, the motor's output torque will be automatically adjusted so that the sensor's output value is within a dynamic and stable range, thus ensuring that the output cable length of the encoder installed at the transmission mechanism remains unchanged.

[0071] In summary, the guiding device for detecting the tension of tethered cables provided in this application has a compact structure, high reliability, and small space occupation. The device is simple to use and highly adaptable to installation, and can be built into various ground devices, such as inside cable boxes or at the bottom or side of takeoff and landing platforms. It avoids the uncertainty caused by manually adjusting the motor output torque based on experience, enabling real-time monitoring of cable tension and providing a reliable basis for autonomous dynamic adjustment of cable tension. It also avoids some manual operations under special extreme weather conditions, improving flight assurance and safety.

[0072] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0073] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0074] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A guiding device for detecting the tension of a mooring cable, characterized in that, include: The guiding mechanism includes a first guide roller, a second guide roller, a third guide roller, and a fourth guide roller, each of which is connected to and cooperates with two side plates; the outer arcs of the first guide roller, the second guide roller, and the third guide roller each form a first guide surface. A clamping mechanism includes a clamping roller and two linear guide rails. The two linear guide rails are horizontally arranged and connected to the two side plates in a one-to-one correspondence. The two ends of the clamping roller are respectively connected to the two linear guide rails through linear guide rail adapter blocks, so that the clamping roller can slide along the horizontal direction of the two linear guide rails. The outer end face arc of the fourth guide roller and the clamping roller forms a second guide surface. A channel for cable passage is formed between the first guide surface and the second guide surface. Two tension detection mechanisms are provided, each including a spring and a tension sensor. The tension sensor is connected to a sensor fixing block on the side plate. One end of the spring is connected to a non-rotatable part of the pressure roller, and the other end of the spring is connected to a spring fixing block on the side plate and cooperates with the sensitive element of the tension sensor so that the tension sensor changes its output value as the length of the spring changes. A controller is communicatively connected to the tension sensor; the controller is used to control the cable retractor to change its working state when it is determined that the sensor output value is not within the target value range, so as to make the sensor output value return to the target value range. The first guide roller, the second guide roller, the third guide roller, and the fourth guide roller all include the same first guide shaft and a first roller that is wrapped around the first guide shaft and can rotate around the first guide shaft; the two ends of each of the first guide shafts are respectively connected to the two side plates. The clamping mechanism also includes a fixing rod, the two ends of which are respectively connected to the two linear guide rail adapter blocks; The pressure roller includes a third guide shaft and a third roller that is wrapped around the third guide shaft and can rotate around the third guide shaft; one end of the spring is connected to a mounting hole on the third guide shaft.

2. The guide device for detecting the tension of a mooring cable according to claim 1, characterized in that, It also includes a set of guide wheels, which consists of two guide wheels arranged vertically and connected to the corresponding side plates via connecting rods.

3. The guide device for detecting the tension of a mooring cable according to claim 2, characterized in that, The stop wheel includes a second guide shaft and a second roller that is wrapped around the second guide shaft and can rotate about the second guide shaft.

4. The guide device for detecting the tension of a mooring cable according to claim 1, characterized in that, The controller is used to control the cable retractor to change its operating state when it determines that the sensor output value is not within the target value range, including: When the sensor output value is determined to be outside the target value range, the output torque and / or take-up speed of the cable take-up and take-up motor are controlled to bring the sensor output value back to the target value range.

5. The guide device for detecting the tension of a mooring cable according to claim 4, characterized in that, When the sensor output value is determined to be less than the minimum value of the target value range, the control cable rewind / unwind motor is adjusted to increase the motor output torque; When the sensor output value exceeds the maximum value of the target value range, the control cable rewind motor is adjusted to reduce the motor output torque.

6. The guide device for detecting the tension of a mooring cable according to claim 4, characterized in that, When the drone is in recovery mode, and the sensor output value is less than the minimum value of the target value range, the cable take-up and take-off motor is controlled to increase the take-up speed; when the sensor output value exceeds the maximum value of the target value range, the cable take-up and take-off motor is controlled to increase the motor output torque. When the drone is in a hovering state and the sensor output value exceeds the maximum value of the target value range, the control cable retractor increases the motor output torque to keep the output cable length of the encoder installed at the transmission mechanism constant.

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