A constant tension drag system tank test apparatus and method of operation

Abstract

A constant tension towing system pool test device and operation method, including trailer base, the trailer base is installed on the slide rail system, including slide rail and rotating shaft, the slide rail is arranged on the trailer base, the rotating shaft is installed at the right end position of the slide rail, the slide rail is fixed after rotating around the rotating shaft, the adjustment of the angle between the slide rail and the longitudinal section in the trailer is realized, the left end of the slide rail is fixed with a fixed pulley;It also includes a support rod system, including a support rod body and a roller, two rollers are arranged above the support rod body, and the support rod body is installed on the slide rail through the two rollers;It also includes a counterweight system, including a light rope, a fixed pulley, a tray and a weight, the two ends of the light rope are connected to the support rod body and the tray respectively, and the middle is turned through the fixed pulley, and the tray contains the weight;It also includes a towing system, the towing system includes a towing body, the towing body is fixed with the trailer base through a tow rope;It also includes a directional mechanism and a plurality of underwater cameras, and the test efficiency is high.

Description

Technical Field

[0001] This invention relates to the field of towing system water tank testing technology, and in particular to a towing system water tank testing device and operating method capable of applying constant tension. Background Technology

[0002] Deep-sea cable deployment and retrieval systems, as well as towed detection systems, have wide applications in engineering. During deep-sea deployment, the cable can be deflected by ocean currents, leading to reduced deployment accuracy. To make minor adjustments to the position of the underwater towed body, a propulsion system on the towed body is typically used to propel it against the current.

[0003] In the water tank test, the current research scheme of using a towed body with a propulsion device to conduct simulation tests has many drawbacks:

[0004] 1. It requires a complex propulsion system and control system;

[0005] 2. It is difficult to guarantee the direction of the thruster's thrust;

[0006] 3. Due to cost and technological limitations, propellers often cannot meet the requirements for size reduction.

[0007] Using a traction cable to provide tension to the towed body, equivalent to thrust from a propeller, is another feasible method. However, towing systems are flexible systems, and after the towed body is towed, the combined effects of hydrodynamics cause complex changes in the shape of the traction cable, making it difficult to pre-set the magnitude and angle of the traction force. While using a fixed pulley with counterweights can provide a constant tension, it cannot maintain a constant traction angle. To maintain a constant traction angle, the secured end of the traction cable needs to move automatically, typically requiring an automated lifting mechanism, as well as measurement, feedback, and closed-loop control—a complex and expensive system. No tank testing apparatus or method for dynamic traction towing systems under constant tension has been reported. Therefore, there is an urgent need for a tank testing apparatus and method that can provide constant traction force to underwater towing systems. Summary of the Invention

[0008] To address the shortcomings of existing production technologies, the applicant provides a water tank testing device and operating method for a towing system capable of applying constant tension, thereby achieving self-constant traction force under no-power conditions, simplifying the testing mechanism, reducing testing costs, and improving testing efficiency.

[0009] The technical solution adopted in this invention is as follows:

[0010] A water tank testing device for a towed system capable of applying constant tension includes a trailer base, on which a slide rail system is mounted. The slide rail system includes a slide rail and a rotating shaft. The slide rail is arranged on the trailer base, and the rotating shaft is installed at the right end of the slide rail. The slide rail rotates around the rotating shaft and then is fixed, allowing adjustment of the angle between the slide rail and the longitudinal section of the trailer. A fixed pulley is fixed at the left end of the slide rail. The device also includes a support rod system, which includes a support rod body and rollers. Two rollers are arranged above the support rod body, and the support rod body is mounted on the slide rail via the two rollers. The support rod body moves horizontally along the slide rail. Finally, the device includes a counterweight system, which includes a light rope, a fixed pulley, a tray, and weights. The two ends of the light rope are connected to the support rod body and the tray, respectively, and the rope is connected in the middle via a fixed pulley. The system includes a pulley for steering, a tray holding weights, a towing system comprising a towing body fixed to a trailer base via a towing cable, a directional mechanism, and multiple underwater cameras. The directional mechanism consists of a collar fitted onto the support rod body, a rotating shaft perpendicular to the support rod body mounted on the collar, a lifting plate connected to the head of the rotating shaft, a first gear mounted in the middle of the rotating shaft, a mounting hole in the middle of the rotating rod into which a wedge-shaped column is inserted, a pair of lifting rings welded to the rotating rod, and first and second directional ropes connected to the lifting rings respectively. The heads of both directional ropes are simultaneously knotted with a traction rope, which is connected to the towing body. A second gear is welded to the outside of the wedge-shaped column, meshing with the first gear, and a spring is installed between the second gear and the collar.

[0011] Its further technical solution lies in:

[0012] The support rod body has a slender and flat structure with a smooth surface.

[0013] The collar moves up and down along the support rod body.

[0014] The collar is made of buoyancy material to maintain zero buoyancy of the entire orientation mechanism underwater.

[0015] Both the traction rope and the directional rope are zero-buoyancy, lightweight thin ropes.

[0016] The spring, the second gear, and the wedge-shaped column are coaxial, and their axis is perpendicular to the support rod body.

[0017] The rotating rod has a long, narrow structure.

[0018] The mounting holes are cylindrical.

[0019] The diameter of the mounting hole is larger than the small circle diameter of the wedge post, but smaller than the large circle diameter of the wedge post.

[0020] A method for operating a water tank test apparatus for a towing system capable of applying constant tensile force includes the following operating steps:

[0021] S1: Setting the experimental parameters,

[0022] S1.1: Set the traction angle θ;

[0023] After pulling the rotating rod out of the wedge-shaped post, rotate it around the axis of the wedge-shaped post to adjust the angle between it and the support rod body to θ, which is the traction angle θ; then, insert the wedge-shaped post into the mounting hole to fix it in place.

[0024] Adjust the lifting plate to a horizontal position and engage gears one and two;

[0025] S1.2: Set the traction angle ψ;

[0026] Release the rotating shaft, and the slide rail will drive the support rod body, light rope, and tray to rotate around the rotating shaft by an angle ψ, thus completing the setting of another traction angle ψ;

[0027] S1.3: Set the traction force T;

[0028] Based on the magnitude of the traction force T to be applied, the weight m = Tcos(θ) / g is obtained, and a weight of m is placed on the tray.

[0029] S1.4: Set the trailer speed V;

[0030] Set the trailer speed on the trailer control terminal;

[0031] S2: Steady-state traction test:

[0032] Once the trailer speed stabilizes, the towing cable system shifts backward under the action of hydrodynamics, pulling the traction rope and thus the directional rope. When the traction rope's angle of inclination is greater than the set angle, for example, if the traction rope is tilted upward, the pulling force on the lower directional rope will be greater than that on the upper directional rope, causing the rotating rod to rotate counterclockwise. The rotating rod drives the second gear to rotate counterclockwise, causing the pre-engaged first gear to rotate clockwise. The first gear drives the lifting plate to rotate clockwise, causing it to lift forward and upward to generate an angle of attack. Under the action of the incoming flow, the lifting plate generates an upward lift force, driving the entire directional mechanism to move upward.

[0033] S3: Dynamic traction test:

[0034] A dynamic traction and towing system was tested by applying a tension force of constant magnitude and direction to simulate the thrust of a propeller.

[0035] After removing the weights, move the support rod body to the far left of the slide rail and start the trailer. As the trailer speed increases, the towing cable drifts backward, and the towing body exerts tension on the traction rope. The traction rope pulls the support rod body. Since the support rod body is not pulled by the weights, it will gradually and slowly move backward. After moving backward, the tension of the traction rope will also gradually decrease. When the towing system reaches a steady state, the tension of the traction rope is weak, and the support rod body no longer moves backward, reaching a stable state. During the process of the traction rope being stressed, the orientation mechanism will move up and down, always maintaining a constant traction angle. Finally, after the cable shape stabilizes, the inclination angle of the traction rope automatically reaches the set angle, completing the preparation work for the dynamic traction test.

[0036] A weight of m is placed on the tray. The tray is slowly pulled forward by a light rope, which in turn pulls the traction rope, which in turn moves the towed body. Due to the directional mechanism, the angle of the traction rope remains constant during the traction process. Therefore, according to the principle of force balance, the traction force is always T = mg / cos(θ). The dynamic process of the towing system is recorded by an underwater camera, and the dynamic movement of the cable and the towed body is measured by a computer image processing algorithm.

[0037] After one test is completed, the weights are removed, and the system will automatically return to its initial state under the action of hydrodynamics. Other weights can then be placed to conduct tests on other traction forces.

[0038] This enabled a traction and towing test in which both the magnitude and direction of the traction force were dynamically kept constant.

[0039] S4: Data Measurement

[0040] Three underwater cameras were placed on the side, above, and behind the towing system, respectively, to acquire images and measure the cable shape and tow body attitude.

[0041] The beneficial effects of this invention are as follows:

[0042] This invention features a compact and rational structure, and is easy to operate. Through the coordinated operation of components such as the trailer base, slide rail system, counterweight system, support rod system, towing system, and traction rope, it can automatically sense the angle deviation of the traction rope, generating hydrodynamic force to raise and lower the orientation mechanism until the traction angle is restored, thus maintaining a constant traction angle. The traction force is set using a counterweight block and a fixed pulley, and the magnitude of the traction force is maintained by the movement of the support rod. Combined with the constant angle of the traction rope, a constant traction force is ultimately achieved. The magnitude and angle of the traction force are easily adjustable, facilitating steady-state and dynamic traction tests under constant tension. This device utilizes hydrodynamic force as the driving force, achieving self-constant traction force even without power, simplifying the test mechanism, reducing test costs, and improving test efficiency.

[0043] This invention can dynamically maintain a constant magnitude and direction of traction force without requiring power input, simplifying the testing equipment, making it easy to operate, and improving testing efficiency.

[0044] This invention can perform both steady-state traction tests and dynamic traction tests, thus improving testing capabilities.

[0045] In addition to providing traction force in the longitudinal section, the present invention can also apply lateral traction force. Attached Figure Description

[0046] Figure 1 This is a general layout diagram of the experimental apparatus of the present invention.

[0047] Figure 2 This is a schematic diagram of the installation of the orientation mechanism of the present invention.

[0048] Figure 3 This is a schematic diagram of the orientation process of the present invention.

[0049] Among them: 1. Trailer base;

[0050] 2. Slide rail system;

[0051] 201. Slide rail; 202. Rotary shaft;

[0052] 3. Counterweight system;

[0053] 301. Light rope; 302. Fixed pulley; 303. Tray; 304. Weights;

[0054] 4. Support rod system;

[0055] 401. Support rod body; 402. Roller;

[0056] 5. Towing system;

[0057] 501. Towing cable; 502. Towing body;

[0058] 6. Towing rope;

[0059] 7. Underwater camera;

[0060] 8. Targeted institutions;

[0061] 801. Collar; 802. Spring; 803. Rotating shaft; 804. Gear No. 1; 805. Gear No. 2; 806. Wedge-shaped column; 807. Lifting plate; 808. Rotating rod; 809. Mounting hole; 810. Directional rope No. 1; 811. Directional rope No. 2. Detailed Implementation

[0062] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0063] like Figures 1-3 As shown, the towing system water tank test device capable of applying constant tensile force in this embodiment includes a trailer base 1, on which a slide rail system 2 is installed. The slide rail system 2 includes a slide rail 201 and a rotating shaft 202. The slide rail 201 is arranged on the trailer base 1, and the rotating shaft 202 is installed at the right end of the slide rail 201. The slide rail 201 is rotated around the rotating shaft 202 and then fixed, thereby adjusting the angle between the slide rail 201 and the longitudinal section of the trailer. A fixed pulley 302 is fixed at the left end of the slide rail 201. It also includes a support rod system. System 4, the support rod system 4 includes a support rod body 401 and rollers 402. Two rollers 402 are arranged on the top of the support rod body 401. The support rod body 401 is mounted on the slide rail 201 via the two rollers 402, and the support rod body 401 moves horizontally along the slide rail 201. It also includes a counterweight system 3, which includes a light rope 301, a fixed pulley 302, a tray 303, and weights 304. The two ends of the light rope 301 are respectively connected to the support rod body 401 and the tray 303, and the fixed pulley 402 passes through the middle. 2. The steering mechanism includes a tray 303 holding weights 304; it also includes a towing system 5, which includes a towing body 502, fixed to the trailer base 1 by a towing cable 501; it also includes a directional mechanism 8 and multiple underwater cameras 7. The directional mechanism 8 has the following structure: it includes a collar 801 fitted onto the support rod body 401, a rotating shaft 803 perpendicular to the support rod body 401 mounted on the collar 801, a lifting plate 807 connected to the head of the rotating shaft 803, and a first gear 803 mounted in the middle of the rotating shaft 803. 4. A mounting hole 809 is opened in the middle of the rotating rod 808. A wedge-shaped column 806 is inserted into the mounting hole 809. A pair of lifting rings are welded on the rotating rod 808. A first directional rope 810 and a second directional rope 811 are connected to the lifting rings respectively. The heads of the two directional ropes are tied to the traction rope 6 at the same time. The traction rope 6 is connected to the towing body 502. A second gear 805 is welded to the outside of the wedge-shaped column 806. The second gear 805 meshes with the first gear 804. A spring 802 is installed between the second gear 805 and the collar 801.

[0064] The support rod body 401 has a slender and flat structure, and the surface of the support rod body 401 is smooth.

[0065] The collar 801 moves up and down along the support rod body 401.

[0066] The collar 801 is made of buoyancy material to maintain the entire orientation mechanism 8 underwater at zero buoyancy.

[0067] Both the traction rope 6 and the directional rope are zero-buoyancy, lightweight thin ropes.

[0068] The spring 802, the second gear 805, and the wedge column 806 are coaxial, and their axis is perpendicular to the support rod body 401.

[0069] The rotating rod 808 has a long strip-shaped structure.

[0070] Mounting hole 809 is a cylindrical structure.

[0071] The diameter of the mounting hole 809 is larger than the small circle diameter of the wedge post 806, but smaller than the large circle diameter of the wedge post 806.

[0072] The specific structure and function of the towing system water tank test device capable of applying constant tensile force described in this invention are as follows:

[0073] It mainly consists of a trailer base 1, a slide rail system 2, a counterweight system 3, a support rod system 4, a towing system 5, a towing rope 6, an underwater camera 7, and a directional mechanism 8.

[0074] The slide rail system 2 is installed on the trailer base 1 and consists of a slide rail 201 and a rotating shaft 202. The rotating shaft 202 is installed at the right end of the slide rail 201. By tightening or loosening the rotating shaft 202, the slide rail 201 can rotate around the rotating shaft 202 and then be fixed, thereby adjusting the angle between the slide rail 201 and the longitudinal section of the trailer.

[0075] The counterweight system 3 consists of a lightweight rope 301, a fixed pulley 302, a tray 303, and weights 304. The lightweight rope 301 is connected at both ends to the support rod body 401 and the lightweight tray 303, respectively, and is deflected by the fixed pulley 302. The fixed pulley 302 is fixed to the left end of the slide rail 201. The tray 303 holds the weights 304.

[0076] The support rod system 4 includes a support rod body 401 and rollers 402. The support rod body 401 is slender and flat with a smooth surface and has two rollers 402 on its top. It is fixed to the slide rail 201 by the two rollers 402, and the support rod body 401 can move horizontally along the slide rail 201.

[0077] Three underwater cameras 7 are placed to the side, above and behind the towing system 5, respectively, for image acquisition to measure the attitude of the cable and tow body 502.

[0078] The orientation mechanism 8 consists of a collar 801, a spring 802, a rotating shaft 803, a gear, a wedge-shaped column 806, a lifting plate 807, a rotating rod 808, a mounting hole 809, and an orientation rope. The collar 801 is fitted onto the support rod body 401 and can move up and down. It is made of buoyancy material and maintains zero buoyancy for the entire orientation mechanism 8 underwater.

[0079] Near each end of the rotating rod 808, a lifting ring is welded, symmetrical about the middle of the rotating rod 808. A cylindrical mounting hole 809 is opened on one side of the center of the rotating rod 808 for inserting and fixing the wedge-shaped post 806. Both the traction rope 6 and the directional rope are zero-buoyancy, lightweight thin ropes. The two directional ropes (directional rope 810 and directional rope 811) are of the same length, one end connected to the two lifting rings respectively, and the other end knotted together with the traction rope 6. The other end of the traction rope 6 is connected to the towing body 502. The spring 802 is connected at both ends to the collar 801 and the second gear 805 respectively, and the wedge-shaped post 806 is welded to the other side of the second gear 805. The spring 802, the second gear 805, and the wedge-shaped post 806 are coaxial, and their axis is perpendicular to the support rod body 401. The rotating shaft 803 is mounted on the collar 801, perpendicular to the support rod body 401, and can rotate around the axis of the rotating shaft 803. The outermost part of the rotating shaft 803 is welded to the lifting plate 807, and a first gear 804 is welded to the middle of the rotating shaft 803. The first gear 804 and the second gear 805 mesh with each other. The diameter of the mounting hole 809 is larger than the small circle diameter of the wedge-shaped post 806, but smaller than the large circle diameter of the wedge-shaped post 806.

[0080] In actual work process:

[0081] First, the experimental parameters were set:

[0082] a. Set the traction angle θ (the angle between the traction rope 6 and the plumb line):

[0083] Pull the rotating rod 808 out of the wedge-shaped post 806 and rotate it around the axis of the wedge-shaped post 806 to adjust the angle between it and the support rod body 401 to θ, which is the traction angle θ. Then, insert the wedge-shaped post 806 into the mounting hole 809 to fix it.

[0084] The lifting plate 807 is adjusted to a horizontal position, and gears 804 and 805 are engaged, with both gears moving simultaneously. Gear 805 is fixedly connected to spring 802. If water flow disturbance or shaking causes the lifting plate 807 to deflect, it will drive the pair of gears to rotate. The rotation of gear 805 will cause spring 802 to twist and store torque. Once the disturbance disappears, the torque of spring 802 will cause the lifting plate 807 to return to a horizontal position. This effectively eliminates small disturbances and maintains the horizontal state of the lifting plate 807.

[0085] b. Set the traction angle ψ (the angle between the vertical plane containing the traction rope 6 and the longitudinal section of the trailer).

[0086] Release the rotating shaft 202, and the slide rail 201 will drive the support rod body 401, the wire rope, and the tray 303 to rotate around the rotating shaft 202 by an angle ψ, thus completing the setting of another traction angle ψ.

[0087] c. Set the traction force T.

[0088] Based on the magnitude of the traction force T to be applied, the weight m = Tcos(θ) / g is obtained, and a weight of m is placed on the tray 303, where g represents gravity.

[0089] d. Set the trailer speed V.

[0090] Set the trailer speed on the trailer control terminal.

[0091] Secondly, steady-state traction test:

[0092] Once the trailer speed stabilizes, the towing cable system shifts backward under hydrodynamic force, pulling the traction cable. The traction cable then pulls the directional rope. When the traction rope's angle is greater than the set angle, for example, if the traction rope is tilted upward, the tension on the lower directional rope will be greater than that on the upper directional rope, causing the rotating rod to rotate counterclockwise. Figure 3 As shown. The rotating rod drives gear 1 to rotate counterclockwise, causing the pre-engaged gear 2 to rotate clockwise. Gear 2 drives the lifting plate to rotate clockwise, causing it to lift forward and upward to generate an angle of attack. Under the action of the incoming flow, the lifting plate generates an upward lift force, driving the entire orientation mechanism to move upward.

[0093] During the upward movement, the angle between the traction rope 6 and the vertical line of the rotating rod 808 gradually decreases, and the tension difference between the traction rope 6 and the first guide rope 810 and the second guide rope 811 gradually decreases, eventually causing the lifting plate 807 to lift at a smaller angle until the traction rope 6 is perpendicular to the rotating rod 808, and the orientation mechanism 8 reaches a stable state.

[0094] When the inclination angle of the traction rope 6 is less than the set inclination angle, the same principle applies: the orientation mechanism 8 will move downwards until a constant inclination angle is reached.

[0095] Weight 304 rests on tray 303 and is held in place by a steel wire rope via pulley 302, pulling the support rod body 401. When tray 303 is stationary or moving at a constant speed relative to the trailer, the tension in the steel wire rope on the support rod body 401 is always equal to the weight of weight 303. Under the action of the orientation mechanism 8, the direction of the tension in the traction rope 6 remains constant at a set angle. The horizontal component of the tension in the traction cable 6 is balanced with the tension in the counterweight.

[0096] The tension in the traction cable is T = mg / cos(θ), and it remains constant.

[0097] When the towing speed is changed, the cable profile of the towing system changes, and the position of the towed body moves vertically and horizontally. After vertical movement, the orientation mechanism 8 automatically rises and falls to maintain a constant inclination angle of the traction cable. After horizontal movement, the traction cable pulls the support rod back and forth to maintain a constant traction force. Therefore, it is possible to conduct tests at different towing speeds in a single towing voyage, greatly improving test efficiency.

[0098] Then, dynamic traction test:

[0099] This device can apply a constant tension force in magnitude and direction to simulate the thrust of a propeller, and conduct tests on dynamic traction and towing systems.

[0100] After removing weight 304, move the support rod body 401 to the leftmost side of the slide rail 201 and start the trailer. As the trailer speed increases, the towing cable sways backward, and the towing body exerts tension on the traction rope, which pulls the support rod body 401. Since the support rod body 401 is not pulled by the weight 304, it will gradually and slowly move backward. After moving backward, the tension of the traction rope 6 will also gradually decrease. When the towing system reaches a steady state, the tension of the traction rope 6 is weak, and the support rod body 401 no longer moves backward, reaching a stable state. During the process of the traction rope 6 being subjected to force, the orientation mechanism 8 will move up and down, always maintaining a constant traction angle. Finally, after the cable shape stabilizes, the inclination angle of the traction rope 6 automatically reaches the set angle, completing the preparation work for the dynamic traction test.

[0101] A weight 304 of weight m is placed on tray 303. Tray 303 slowly pulls the support rod body 401 forward via light rope 301, which in turn pulls the traction rope 6, causing the towed body to move. Due to the action of the orientation mechanism 8, the included angle of the traction rope 6 remains constant throughout the traction process. Therefore, according to the principle of force balance, the traction force is always T = mg / cos(θ). The dynamic process of the towing system is recorded by underwater camera 7, and the dynamic movement of the cable and towed body is dynamically measured using computer image processing algorithms.

[0102] After one test is completed, the weight 304 is removed, and it will automatically return to its initial state under the action of hydrodynamic force. Other weights of weight 304 can then be placed to conduct tests on other traction forces.

[0103] This enabled a traction test in which both the magnitude and direction of the traction force were dynamically kept constant.

[0104] Finally, data measurement:

[0105] Three underwater cameras 7 are placed on the side, above and behind the towing system, respectively, for image acquisition to measure the cable shape and tow body attitude.

[0106] The above operating method allows for the convenient completion of the entire test process. By using hydrodynamics as the driving force, the traction force is kept constant even without power, simplifying the test mechanism, reducing test costs, and improving test efficiency.

[0107] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. A water tank test apparatus for a towing system capable of applying constant tensile force, characterized in that: The system includes a trailer base (1), on which a slide rail system (2) is installed. The slide rail system (2) includes a slide rail (201) and a rotating shaft (202). The slide rail (201) is arranged on the trailer base (1). The rotating shaft (202) is installed at the right end of the slide rail (201). The slide rail (201) is fixed after rotating around the rotating shaft (202) to adjust the angle between the slide rail (201) and the longitudinal section of the trailer. A fixed pulley (302) is fixed at the left end of the slide rail (201). The system also includes a support rod system (4), which includes a support rod body (401). The support rod body (401) is equipped with two rollers (402) on its upper part. The support rod body (401) is mounted on the slide rail (201) via the two rollers (402). The support rod body (401) moves horizontally along the slide rail (201). The support rod body (401) also includes a counterweight system (3), which comprises a light rope (301), a fixed pulley (302), a tray (303), and weights (304). The two ends of the light rope (301) are connected to the support rod body (401) and the tray (303) respectively, and the rope is turned via the fixed pulley (302) in the middle. The weights on the tray (303) are... The system includes a weight container (304); it also includes a towing system (5), which includes a towing body (502) fixed to a trailer base (1) via a towing cable (501); it also includes a directional mechanism (8) and multiple underwater cameras (7). The directional mechanism (8) has the following structure: it includes a collar (801) fitted onto the support rod body (401), a rotating shaft (803) perpendicular to the support rod body (401) mounted on the collar (801), a lifting plate (807) connected to the head of the rotating shaft (803), and a first gear (804) mounted in the middle of the rotating shaft (803). A mounting hole (809) is opened in the middle of the moving rod (808). A wedge-shaped column (806) is inserted into the mounting hole (809). A pair of lifting rings are welded on the rotating rod (808). A first directional rope (810) and a second directional rope (811) are connected to the lifting rings respectively. The heads of the two directional ropes are tied to the traction rope (6) at the same time. The traction rope (6) is connected to the towing body (502). A second gear (805) is welded on the outside of the wedge-shaped column (806). The second gear (805) meshes with the first gear (804). A spring (802) is installed between the second gear (805) and the collar (801).

2. The water tank test device for a towing system capable of applying constant tension as described in claim 1, characterized in that: The support rod body (401) has a slender and flat structure, and the surface of the support rod body (401) is smooth.

3. The water tank test device for a towing system capable of applying constant tension as described in claim 1, characterized in that: The collar (801) moves up and down along the support rod body (401).

4. The water tank test device for a towing system capable of applying constant tension as described in claim 1, characterized in that: The collar (801) is made of buoyancy material to maintain the entire orientation mechanism (8) underwater zero buoyancy.

5. The water tank test device for a towing system capable of applying constant tension as described in claim 1, characterized in that: Both the traction rope (6) and the directional rope are zero-buoyancy, lightweight thin ropes.

6. The water tank test device for a towing system capable of applying constant tension as described in claim 1, characterized in that: The spring (802), the second gear (805), and the wedge column (806) are coaxial, and their axis is perpendicular to the support rod body (401).

7. The water tank test device for a towing system capable of applying constant tension as described in claim 1, characterized in that: The rotating rod (808) has a long strip structure.

8. The water tank test device for a towing system capable of applying constant tension as described in claim 1, characterized in that: The mounting hole (809) is a cylindrical structure.

9. A water tank test apparatus for a towing system capable of applying constant tension as described in claim 1, characterized in that: The diameter of the mounting hole (809) is greater than the small circle diameter of the wedge post (806) and smaller than the large circle diameter of the wedge post (806).

10. A method for operating a water tank test apparatus for a towing system capable of applying constant tension as described in claim 1, characterized in that: The following steps are included: S1: Setting the experimental parameters, S1.1: Set traction angle ; After pulling the rotating rod (808) off the wedge-shaped column (806), rotate it around the axis of the wedge-shaped column (806) to adjust the angle between it and the support rod body (401). That is, the angle of traction force. Then, the wedge-shaped post (806) is inserted into the mounting hole (809) to achieve fixation; Adjust the lifting plate (807) to a horizontal position and engage the first gear (804) and the second gear (805); S1.2: Set the traction angle ; Release the rotating shaft (202), and the slide rail (201) will drive the support rod body (401), the light rope (301), and the tray (303) to rotate together around the rotating shaft (202). Angle, that is, the angle at which another traction force is completed. The settings; S1.3: Set the traction force T; The weight of the weight is determined based on the magnitude of the traction force T to be applied. And place a weight (304) of weight m on the tray (303). S1.4: Set the trailer speed V; Set the trailer speed on the trailer control terminal; S2: Steady-state traction test: Once the trailer speed stabilizes, the towing cable system shifts backward under the action of hydrodynamics, pulling the traction rope (6), which in turn pulls the directional rope. When the traction rope's inclination angle is greater than the set inclination angle, the pulling force on the directional rope below will be greater than that on the directional rope above, causing the rotating rod (808) to rotate counterclockwise. The rotating rod (808) drives the second gear (805) to rotate counterclockwise, causing the pre-engaged first gear (804) to rotate clockwise. The first gear (804) drives the lifting plate (807) to rotate clockwise, causing it to lift forward and upward to generate an angle of attack. Under the action of the incoming flow, the lifting plate (807) generates an upward lift force, driving the entire directional mechanism (8) to move upward. S3: Dynamic traction test: A dynamic traction and towing system was tested by applying a tension force of constant magnitude and direction to simulate the thrust of a propeller. After removing the weight (304), move the support rod body (401) to the leftmost side of the slide rail (201), start the trailer, and as the trailer speed increases, the towing cable drifts backward, and the towing body generates tension on the traction rope (6). The traction rope (6) pulls the support rod body (401). Since the support rod body (401) is not pulled by the weight (304), the support rod body (401) will gradually move backward slowly. After moving backward, the tension of the traction rope (6) will also gradually decrease. When the towing system (5) reaches a steady state, the tension of the traction rope (6) is weak, and the support rod body (401) will no longer move backward, reaching a stable state. During the process of the traction rope (6) being subjected to force, the orientation mechanism (8) will move up and down, always keeping the traction force angle constant. Finally, after the cable shape is stable, the inclination angle of the traction rope (6) will automatically reach the set angle, completing the preparation work for the dynamic traction test. A weight (304) of weight m is placed on the tray (303). The tray (303) slowly pulls the support rod body (401) forward via a light rope (301). The support rod body (401) pulls the traction rope (6), and the traction rope (6) pulls the towing body (502) to move. Due to the action of the orientation mechanism (8), the included angle of the traction rope remains constant during the traction process. Therefore, according to the principle of force balance, the traction force is always... The dynamic process of the towing system (5) is recorded by an underwater camera (7), and the dynamic measurement of the cable and towing body motion is performed by a computer image processing algorithm. After one test is completed, the weight (304) is removed and will automatically return to its initial state under the action of hydrodynamic force. Other weights (304) can be placed again to conduct other traction force tests. This enabled a traction and towing test in which both the magnitude and direction of the traction force were dynamically kept constant. S4: Data Measurement Three underwater cameras (7) are placed to the side, above and behind the towing system (5) respectively for image acquisition to measure cable shape and towing body attitude.

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