Cable stringing system

Abstract

The present invention addresses the problem of providing a cable stringing system and a cable stringing method which make it possible, even for an unskilled person, to easily draw a cable between diameters by using an areal vehicle.　A cable stringing system according to the present invention is for stringing a cable 50 between two columns 10, and is characterized by comprising: an areal vehicle that grips one end of the cable 50 and moves from one of the columns 10 to the other; a cable feed-out device 12a that is installed in one of the columns 10 and that applies a braking force to the cable 50 which is fed out by the movement of the areal vehicle to generate desired tension in the cable 50; and an arithmetic device 40 that calculates the desired tension on the basis of the position of the areal vehicle and gives an instruction to the cable feed-out device 12a about the braking force that generates the desired tension.

Description

Cable Installation System

[0001] The present disclosure relates to a system and method for pulling a cable between spans using an air vehicle.

[0002] When pulling a cable between utility poles 10 and another utility pole 10, as shown in Figure 1, a towing rope or the like called a pulling string 51 must be connected to the tip of cable 50, and a worker 20 must pull the pulling string 51 using a pulley 11 or the like. As the span distance increases, the pulling force and work time for cable pulling work also increase, and workers 20 must be stationed not only on the pulling side but also on the cable payout side.

[0003] JP 2012-210038 A

[0004] NTT e-drone website, "Omakase e-drone," retrieved April 14, 2023

[0005] Although there is technology for pulling cables using robots or the like in narrow pipes, as in Patent Document 1, there is no established method for pulling cables outdoors. In addition, with the current work, the work becomes extremely difficult when there are obstacles such as rivers or valleys or undulating areas between utility poles, and there is an issue that requires the training of skilled workers.

[0006] FIG. 2 is a diagram illustrating the operation of pulling a cable between spans using an aircraft such as a drone, as disclosed in Non-Patent Document 1. In this operation, a cable 50 is grasped by a drone 30 equipped with a cable gripping mechanism, and the drone 30 is flown from one utility pole 10 to another, thereby enabling the cable to be pulled regardless of obstacles between the spans. However, if sufficient tension is not generated in the cable when the drone grasps the cable and flies to pay out the cable, the load on the drone will vary with each operation depending on the length of the cable being paid out. For this reason, the operation method disclosed in Non-Patent Document 1 requires the drone's propulsion output to rely on experience and intuition, and poses the problem of difficulty in stably flying the drone unless the drone is skilled.

[0007] Therefore, in order to solve the above problems, the present invention aims to provide a cable installation system and method that allows even unskilled personnel to easily lay cables between spans using an aircraft.

[0008] In order to achieve the above-mentioned object, the cable erection system of the present invention is configured to install a cable payout device having a braking mechanism that applies a brake to the payout of the cable on the utility pole on the cable payout side so that the horizontal tension generated in the cable remains constant.

[0009] Specifically, the cable installation system of the present invention is an installation system that spans a cable between two pillars, and is characterized by comprising: an aircraft that holds one end of the cable and moves from one side of the pillar to the other; a cable payout device that is installed on one of the pillars and applies a braking force to the cable that is paid out by the movement of the aircraft, thereby generating a desired tension in the cable; and a computing device that calculates the desired tension based on the position of the aircraft and instructs the cable payout device on the braking force that will result in the desired tension.

[0010] Furthermore, the cable installation method of the present invention is an installation method in which one end of the cable is held by a flying object and the flying object is moved from one of the pillars to the other to lay the cable between two pillars, and is characterized by: installing a cable payout device on one of the pillars that applies a braking force to the cable that is paid out by the movement of the flying object, thereby generating a desired tension in the cable; calculating the desired tension based on the position of the flying object; and instructing the cable payout device on the braking force that will result in the desired tension.

[0011] While the aircraft is flying, the tension of the cable can be controlled by applying a braking force to the cable being reeled out. Controlling the tension of the cable allows the aircraft to fly stably. Therefore, the present invention provides a cable installation system and method that allows even an unskilled person to easily pull a cable between spans using an aircraft.

[0012] The computing device is characterized by calculating the sag and actual cable length from the optimum tension set for the cable stretched between the pillars, the weight per unit length of the cable, and the span distance.

[0013] The computing device is characterized by calculating the flight path from the flight start position of the aircraft to the attachment position of the cable on the other side of the pillar, and the flight attitude and flight speed of the aircraft from external forces from the natural world.

[0014] The computing device is characterized by: calculating a maximum horizontal tension generated when the cable is stretched based on the payload of the aircraft and the flight path; and calculating the braking force that is smaller than the maximum horizontal tension and such that the speed of the cable being unwound from the cable unwinding device is equal to or less than the flight speed of the aircraft.

[0015] The arithmetic device of the present invention can also be realized by a computer and a program, and the program can be recorded on a recording medium or provided via a network.

[0016] The above inventions can be combined as much as possible.

[0017] The present invention can provide a cable installation system and method that allows even an unskilled person to easily lay cables between spans using an aircraft.

[0018] FIG. 1 is a diagram illustrating a conventional cable erection method. FIG. 2 is a diagram illustrating a cable erection method using an aircraft. FIG. 3 is a diagram illustrating a cable erection system according to the present invention. FIG. 4 is a diagram illustrating a cable pay-out device of the cable erection system according to the present invention. FIG. 5 is a diagram illustrating a cable receiving device of the cable erection system according to the present invention. FIG. 6 is a diagram illustrating a cable erection system according to the present invention. FIG. 7 is a diagram illustrating a cable erection method according to the present invention. FIG. 8 is a diagram illustrating a method of calculating a braking force in the cable erection method according to the present invention.

[0019] The following description of the preferred embodiments of the present invention will be given with reference to the accompanying drawings. The preferred embodiments described below are examples of the present invention, and the present invention is not limited to the preferred embodiments. In this specification and the drawings, components having the same reference numerals are intended to represent the same components.

[0020] 3 is a diagram illustrating an installation system according to this embodiment. This installation system suspends a cable 50 between two pillars 10 and is characterized by comprising: an aircraft that holds one end of the cable 50 and moves from one side of the pillars 10 to the other; a cable payout device 12a that is installed on one of the pillars 10 and applies a braking force to the cable 50 that is paid out as the aircraft moves, thereby generating a desired tension in the cable 50; and a computing device 40 that calculates the desired tension according to the position of the aircraft and instructs the cable payout device 12a on the braking force that will result in the desired tension. Note that this embodiment will be described using a drone 30 as the aircraft.

[0021] This erection system includes a cable reeling device 12a for generating tension in the cable 50 that enables stable flight of the drone. Figure 4 is a diagram illustrating the cable reeling device 12a. The cable reeling device 12a includes a pulley 12-1, a utility pole mounting member 12-2, and a brake mechanism 12-3 for adjusting the reeling speed of the cable 50. The pulley 12-1 also has sufficient friction to prevent the cable 50 from slipping on its cable contact surface, resulting in poor transmission of the braking force B from the brake mechanism 12-3 to the cable 50. Since the cable reeling device 12a is installed on the top of the utility pole 10, it has a shape and weight that allows it to be attached with a utility pole fixing band.

[0022] A cable receiving device 13 is also installed on the top of the other utility pole. Figure 5 is a diagram illustrating the cable receiving device 13. The cable receiving device 13 has a pulley 13-1 and a ratchet mechanism 13-2. The ratchet mechanism 13-2 receives the cable 50 transported by the drone 30 and prevents the cable 50 from unwinding. The pulley 13-1 has sufficient friction to prevent the cable 50 from slipping on its cable contact surface and causing unwinding. Since the cable receiving device 13 is also installed on the top of the utility pole 10, it has a shape and weight that allows it to be attached with a utility pole fixing band.

[0023] The calculation device 40 applies a predetermined horizontal tension F to the cable 50 when the drone 30 transports the cable 50 to the cable receiving device 13. ｆ The braking force B is instructed to the brake mechanism 12-3 of the cable payout device 12a so that the braking force B is generated, and the payout speed of the cable 50 is adjusted. The speed of the drone 30 can be controlled by this braking force B.

[0024] 6 is a functional block diagram illustrating the erection system of this embodiment. The drone 30 measures its own position, flight speed, and attitude using a GPS and an IMU (Inertial Measurement Unit), and notifies the calculation device 40. In addition, the operator can also view images captured by a camera mounted on the drone 30 via the calculation device 40.

[0025] As will be described later, the computing device 40 calculates the flight attitude and optimal flight path from information from the drone 30 and information on external forces from the natural world, such as wind speed. The optimal flight path is, for example, a straight line connecting the current position of the drone 30 to the flight end position. Here, the flight end position refers to the cable receiving bracket of the cable receiving device 13, the position above the cable receiving bracket, or the position below the cable receiving bracket, and is provided to the computing device 40 before the cable pulling work. The computing device 40 notifies the drone 30 of the optimal flight path.

[0026] 7 is a diagram illustrating a method for calculating the flight attitude and optimal flight path performed by the computing device 40. First, the computing device 40 calculates the optimal horizontal tension T to be applied to the cable 50 to be laid between the utility poles 10 (step S11). Specifically, the computing device 40 measures the distance S between the utility poles 10 (a design value may be input), and calculates the optimal tension T from the type of cable 50 to be laid between the utility poles 10 (cable weight W per unit length) and the distance S between the utility poles 10. Here, the optimal tension T is a tension that is equal to or less than the breaking strength of the cable at the expected maximum wind speed, and that increases the minimum ground clearance of the cable to a predetermined height.

[0027] Next, the calculation device 40 calculates the slack D and length L of the cable 50 (step S12). Specifically, using equation (1), the calculation device 40 calculates the slack D from the tension T calculated in step S11 and the weight W per unit length of the cable 50. The calculation device 40 confirms that the slack D is not below a preset minimum ground clearance. Then, the calculation device 40 calculates the length L of the cable 50 used for pulling (actual cable length) using equation (2). After step S12, by pulling out the required actual length of cable 50 from cable drum 52 in advance, it is possible to reduce errors between the various values ​​(including the flight path) calculated by the calculation device 40 and the values ​​(including the flight path) during the pulling work.

[0028] Next, the computing device 40 calculates the flight path of the drone 30 from the flight start position and flight end position of the drone 30 (step S13). The tip of the cable 50 pulled out from the cable drum 52 may be passed through the pulley 12-1 of the cable reel-out device 12a in advance and then lowered to the ground, and the tip of the cable 50 placed on the ground may be gripped by the cable gripping unit of the drone 30. Alternatively, the tip of the cable 50 may be gripped by the cable gripping unit of the drone 30 near the cable reel-out device 12a. In other words, the flight start position may be on the ground near the utility pole 10 on which the cable reel-out device 12a is installed, or may be above it (near the cable reel-out device 12a).

[0029] Furthermore, the computing device 40 can also calculate the flight attitude and speed of the drone 30 based on external forces such as wind speed on the day (step S14).

[0030] Meanwhile, the computing device 40 calculates the braking force B required for stable flight, which will be described later, and notifies the cable payout device 12a. Fig. 8 is a diagram illustrating a method for calculating the braking force B. First, the computing device 40 calculates the maximum horizontal tension T that will be the maximum when pulling the cable through, based on the maximum weight (payload) M that the drone 30 can carry and the flight path calculated above. ｆｍａｘ (Step S21). Here, the horizontal tension T ｆ This article explains:

[0031] In a static state, the cable 50 having a catenary curve shape is subjected to a horizontal tension T ０ occurs.

[0032] The payload M is the weight that can be transported vertically downward. On the other hand, the horizontal tension F ｆ is the tension applied in the flight direction of the drone 30, and the horizontal tension T ０ and the braking force B by the brake mechanism 12-3 of the cable payout device 12a, and is divided into horizontal forces. ｆ It is necessary to be larger than M>T. [Equation 4] ｆ tan θ = (T ０ +B) tan θ where θ is the flight angle of the drone 30 as shown in FIG. 9 (the angle between the horizontal and the straight line connecting the flight start position and the current position of the drone 30). ｆ T, which is the maximum value of ｆｍａｘ can be calculated.

[0033] Finally, the calculation device 40 calculates the braking force B. The horizontal tension T ０The horizontal tension T ０ Since changes depending on the position of the drone 30, the calculation device 40 may constantly acquire information from the drone 30 and change the braking force B.

[0034] The pilot flies the drone based on the calculated drone speed and optimal flight path, and when the drone passes the position of the cable receiving device 13, the pilot has the cable 50 grasped by the receiving fitting of the cable receiving device 13. After confirming that sufficient tension is applied to the cable 50, the pilot ends the drone 30's grip on the cable, enabling optimal cable pulling. Finally, the cable 50 located at the cable payout device 12a and the cable receiving device 13 is fixed to the utility pole 10, completing the pulling work.

[0035] 10: Utility pole 11: Pulley 12, 12a: Cable payout device 12-1: Pulley 12-2: Utility pole mounting member 12-3: Brake mechanism 13: Cable receiving device 13-1: Pulley 13-2: Ratchet mechanism 20: Worker 30: Drone 40: Computing device 50: Cable 51: Pulling cord 52: Cable drum

Claims

1. An installation system for spanning a cable between two pillars, comprising: an aircraft that holds one end of the cable and moves from one side of the pillar to the other; a cable payout device that is installed on one of the pillars and applies a braking force to the cable that is paid out as the aircraft moves, thereby generating a desired tension in the cable; and a calculation device that calculates the desired tension according to the position of the aircraft, and instructs the cable payout device on the braking force that will result in the desired tension.

2. The erection system according to claim 1, characterized in that the computing device calculates the sag and actual cable length from the optimal tension set for the cable stretched between the pillars, the weight per unit length of the cable, and the span distance.

3. The installation system described in claim 1, characterized in that the computing device calculates the flight path from the flight start position of the aircraft to the attachment position of the cable on the other side of the pillar, and the flight attitude and flight speed of the aircraft from external forces from the natural world.

4. The installation system described in claim 3, characterized in that the computing device calculates a maximum horizontal tension generated when erecting the cable based on the payload of the aircraft and the flight path, and calculates the braking force that is smaller than the maximum horizontal tension and such that the speed of the cable reeled out from the cable reeling device is equal to or less than the flight speed of the aircraft.

5. An installation method in which one end of a cable is held by an aircraft and the aircraft is moved from one pillar to the other to span the cable between two pillars, the installation method comprising the steps of: installing a cable payout device on one of the pillars that applies a braking force to the cable as it is paid out by the movement of the aircraft, thereby generating a desired tension in the cable; calculating the desired tension based on the position of the aircraft; and instructing the cable payout device on the braking force that will result in the desired tension.

6. The method of erection according to claim 5, characterized in that the sag and actual cable length are calculated from the optimum tension set for the cable stretched between the pillars, the weight per unit length of the cable, and the span distance.

7. The installation method described in claim 5, characterized in that the flight path from the flight start position of the flying object to the attachment position of the cable on the other side of the pillar, and the flight attitude and flight speed of the flying object are calculated from external forces from the natural world.

8. The installation method described in claim 7, characterized by: calculating a maximum horizontal tension generated when stretching the cable based on the payload of the aircraft and the flight path; and calculating the braking force which is smaller than the maximum horizontal tension and such that the speed of the cable reeled out from the cable reeling device is equal to or lower than the flight speed of the aircraft.

Images