A thrust experimental device of a gravity center position adjustable underwater propeller and an experimental method thereof

Abstract

The application discloses a thrust test device of a gravity center position adjustable underwater propeller, which comprises a test pool, a rotating arm assembly for driving the underwater propeller to rotate circumferentially in the test pool and a thrust test device. The thrust test device comprises a horizontal sliding force measuring platform and a gravity center adjusting mechanism. The horizontal sliding force measuring platform is used for measuring the horizontal thrust of the underwater propeller, and a roller moves along a sliding rail on a baffle of the horizontal sliding platform. The gravity center adjusting mechanism comprises a first screw rod sliding platform and a second screw rod sliding platform which are perpendicular to each other. The underwater propeller adjusts the position relative to the horizontal sliding force measuring platform through the first screw rod sliding platform and the second screw rod sliding platform. The underwater propeller makes circumferential motion in the test pool. The rotating motion mode can generate less turbulence during the test, so that the test process is less disturbed and more stable. The position of the gravity center of the underwater propeller in the measuring device is adjusted, which is favorable for reducing the error interval of the thrust measurement result and improving the measurement precision.

Description

Technical Field

[0001] This invention relates to an underwater thrust test apparatus, specifically to an underwater thrust test apparatus and test method for an underwater thruster with an adjustable center of gravity. Background Technology

[0002] Underwater robots are playing an increasingly important role in marine science, deep-sea exploration, and underwater engineering. As the core power component of underwater robots, underwater thrusters are crucial for propelling them to perform tasks in underwater environments. Their thrust performance directly affects the robot's speed, maneuverability, and stability and flexibility in complex underwater environments. Thrust testing devices are important tools for evaluating the thrust performance of underwater thrusters.

[0003] In the prior art, for example, Chinese patent application number 202221571516.8 discloses a propeller thruster testing device. This device transmits the thrust of the thruster along the slide rail direction to a tension / compression sensor for measurement via a slide rail platform. Another example is Chinese patent application number 201910560149.8, which discloses an underwater biomimetic thruster testing platform. This platform uses a pair of intersecting slide rails to measure the magnitude of the thrust of the underwater thruster in the horizontal and vertical directions. In both of these testing devices, the sensor readings directly reflect the thrust of the thruster along the slide rail direction at different speeds, directly using the sensor readings as the thrust without additional calculation. However, the testing device itself has a fixed position and cannot measure the thrust during movement. For example, in the Chinese patent application with application number 201820344124.5, the pusher is fixed below the slider and moves linearly along the guide rail to squeeze the pressure sensor. This device can simulate the water flow when the pusher moves forward and measure the thrust of the pusher when it moves. However, since the device uses a linear guide rail, the pusher still needs to move smoothly for a period of time after reaching the target speed, so it is difficult to reduce the size of the measuring device. Summary of the Invention

[0004] Purpose of the invention: To address the above problems, the present invention provides a thrust experimental device for an underwater thruster with an adjustable center of gravity position, which reduces measurement errors by offsetting the additional torque generated by the thruster's motion through center of gravity shift.

[0005] The present invention also provides an experimental method for testing the thrust of the above-mentioned underwater thruster.

[0006] Technical Solution: To solve the above problems, the present invention employs a thrust testing device for an underwater thruster with an adjustable center of gravity, comprising a test pool, a rotary arm assembly that drives the underwater thruster to rotate circumferentially in the test pool, and a thrust testing device disposed between the rotary arm assembly and the underwater thruster. The thrust testing device includes a horizontal sliding force measuring platform and a center of gravity adjustment mechanism. The horizontal sliding force measuring platform includes a horizontal sliding upper baffle connected to the rotary arm assembly, a slide rail disposed on the horizontal sliding upper baffle, a horizontal sliding lower baffle, a roller disposed on the horizontal sliding lower baffle, and a tension / compression sensor disposed between the horizontal sliding upper baffle and the horizontal sliding lower baffle. The roller moves along the slide rail on the horizontal sliding upper baffle, and the slide rail extends along the thrust direction of the underwater thruster.

[0007] The center of gravity adjustment mechanism includes a first lead screw slide and a second lead screw slide. Both the first and second lead screw slides include a slide base plate, a lead screw mounted on the slide base plate, a lead screw slide drive motor for driving the lead screw to rotate, and a slider threadedly connected to the lead screw. The slide base plate of the first lead screw slide is fixedly connected to a horizontal slide lower baffle, and the slide base plate of the second lead screw slide is fixedly connected to the slider of the first lead screw slide. The slider of the second lead screw slide is fixedly connected to an underwater thruster. The extension directions of the lead screws of the first and second lead screw slides are perpendicular to each other.

[0008] Furthermore, the thrust testing device also includes an angle adjustment device, which includes a rotating platform connecting plate connected to the rotating arm assembly, a rotating platform base fixedly connected to the rotating platform connecting plate, a rotating worktable cooperating with the rotating platform base, a locking ring sleeved on the outside of the rotating worktable, a locking seat, and a locking screw threaded onto the locking seat. The rotating platform base and the rotating worktable rotate relative to each other. The rotating worktable is fixedly connected to a baffle on a horizontal slide. The thrust direction of the underwater thruster is adjusted by rotating the rotating worktable. The end of the locking screw abuts against the outer ring of the rotating worktable. The locking screw is positioned on the rotating platform base. Tightening the locking screw fixes the locking ring, the rotating platform base, and the rotating worktable.

[0009] Furthermore, the angle adjustment device also includes a left-turn fine-tuning screw, a right-turn fine-tuning screw, and a fine-tuning support. The left-turn and right-turn fine-tuning screws are threadedly connected to both sides of the fine-tuning support. The adjusting end of the locking screw is located between the left-turn and right-turn fine-tuning screws, and the left-turn and right-turn fine-tuning screws are located on both sides of the adjusting end of the locking screw. Adjusting the left-turn and right-turn fine-tuning screws allows for fine-tuning of the rotary table through the locking screw.

[0010] Furthermore, the slide rail set on the baffle of the horizontal slide platform includes I-beams on both sides of the bottom surface of the baffle of the horizontal slide platform and an inner baffle of the horizontal slide platform located in the middle of the bottom surface of the baffle of the horizontal slide platform. Roller bases are set on both sides of the lower baffle of the horizontal slide platform, and a plurality of first roller groups are set on the roller bases. The first roller group includes two rollers symmetrically arranged. The roller axes of the two rollers of the first roller group are parallel to the plane of the baffle of the horizontal slide platform. The base plate of the I-beam is located between the two rollers of the first roller group, and the two rollers of the first roller group move along the I-beam. A plurality of second roller groups are set in the middle of the lower baffle of the horizontal slide platform. The second roller group includes two rollers symmetrically arranged. The roller axes of the two rollers of the second roller group are perpendicular to the plane of the baffle of the horizontal slide platform and parallel to the plane of the inner baffle of the horizontal slide platform. The inner baffle of the horizontal slide platform is located between the two rollers of the second roller group, and the two rollers of the second roller group move along the inner baffle of the horizontal slide platform.

[0011] Furthermore, the first lead screw slide and the second lead screw slide also include an adjusting slide rail fixedly connected to the slide base plate, an adjusting slider that slides relative to the adjusting slide rail, and a slider support plate fixedly connected to the adjusting slider, wherein the slider and the slider support plate are fixedly connected.

[0012] Furthermore, the rotating arm assembly includes a column extending vertically upward from the center of the test pool, a lower hinge rotatably connected to the column, a crossbeam hinged to the lower hinge, an internal gear positioned at the end of the crossbeam, and an internal gear drive motor that drives the internal gear to rotate. An external gear meshing with the internal gear is arranged circumferentially around the test pool. The internal gear drive motor is fixedly connected to the crossbeam and drives the crossbeam to rotate around the column by driving the internal gear to rotate. The thrust testing device is connected to the crossbeam.

[0013] Furthermore, a cantilever support frame is provided around the test pool, and a third roller group is provided at the end of the crossbeam. The third roller group includes a symmetrically arranged upper cantilever roller and a lower cantilever roller. The roller axes of the upper and lower cantilever rollers are parallel to the extension direction of the crossbeam. The upper top plate of the cantilever support frame is located between the upper and lower cantilever rollers, and the upper and lower cantilever rollers move along the cantilever support frame.

[0014] The present invention also employs an experimental method for the above-mentioned thrust experimental apparatus, comprising the following steps:

[0015] Step 1: Determine the test parameters, including the propeller rotation speed of the underwater thruster, the angular velocity of the underwater thruster in the test pool, and the angle between the thrust direction and the velocity direction of the underwater thruster;

[0016] Step 2: Determine the center of gravity of the underwater thruster in the thrust testing device based on the test parameters;

[0017] Step 3: Adjust the center of gravity of the underwater thruster in the thrust testing device;

[0018] Step 4: Conduct the test according to the test parameters.

[0019] Furthermore, the formula for calculating the center of gravity position of the underwater thruster in the thrust testing device is as follows:

[0020]

[0021] Among them, X g Y is the distance from the center of gravity of the underwater thruster along the X-axis to the center of the horizontal sliding force measuring platform. g Let Ω be the distance from the center of gravity of the underwater thruster along the Y-axis to the center of the horizontal sliding force measuring platform, Ω be the angular velocity of the underwater thruster in the test pool, R be the horizontal distance from the center of gravity of the underwater thruster to its fixed point, H be the distance from the center of gravity of the underwater thruster along the Z-axis to the center of the horizontal sliding force measuring platform, θ be the angle between the thrust direction and the velocity direction of the underwater thruster, B be the distance from the point of application of the supporting force on the horizontal sliding force measuring platform along the Y-axis to the center of the horizontal sliding force measuring platform, A be the distance from the point of application of the supporting force on the horizontal sliding force measuring platform along the X-axis to the center of the horizontal sliding force measuring platform, g be the acceleration due to gravity, and J be the acceleration due to gravity. Z Let ω be the moment of inertia of the propeller rotor about the Z-axis, ω be the rotational speed of the underwater propeller blades, m be the mass of the underwater propeller, and F be the thrust of the underwater propeller.

[0022] Beneficial Effects: Compared with existing technologies, the significant advantage of this invention is that the underwater thruster moves circumferentially in the test pool, and the rotational motion generates less turbulence during testing, resulting in less interference and greater stability. Adjusting the position of the underwater thruster's center of gravity within the measuring device helps reduce the error range of the thrust measurement results, improving measurement accuracy. Using an internal meshing gear as the drive mechanism allows for a longer power arm and better force transmission, enabling the testing device to quickly reach the preset speed. The angle adjustment device adjusts the test angle between the thrust direction and the velocity direction of the thruster. The locking ring provides support and stabilizes the testing device, the locking screw makes angle adjustment convenient, and the fine-tuning screw makes angle adjustment more precise. Attached Figure Description

[0023] Figure 1 A schematic diagram of the overall structure of the thrust experimental device of the present invention;

[0024] Figure 2 A schematic diagram of the thrust testing device connected to the underwater thruster in this invention;

[0025] Figure 3 Front view of the angle adjustment device in this invention;

[0026] Figure 4 for Figure 3 Sectional view at point AA;

[0027] Figure 5 Left view of the horizontal sliding force measuring stage in this invention;

[0028] Figure 6 Front view of the horizontal sliding force measuring stage in this invention;

[0029] Figure 7 for Figure 6 Sectional view at point GG;

[0030] Figure 8 Axonometric view of the frame on the horizontal sliding force measuring platform in this invention;

[0031] Figure 9 Axonometric view of the lower frame of the horizontal sliding force measuring table in this invention;

[0032] Figure 10 Front view of the center of gravity adjustment device in this invention;

[0033] Figure 11 for Figure 10 Sectional view at point BB;

[0034] Figure 12 Front view of the thrust testing device in this invention;

[0035] Figure 13 for Figure 12 Sectional view at point DD;

[0036] Figure 14 A cross-sectional view of the connection between the test tank and the rotating arm assembly in this invention;

[0037] Figure 15 for Figure 14 Enlarged schematic diagram of partial view I in the middle;

[0038] Figure 16 for Figure 14 Enlarged schematic diagram of partial view III;

[0039] Figure 17 This is a motion diagram of the thrust experimental device of the present invention;

[0040] Figure 18 This is a schematic diagram of the forces acting on the thruster in this invention;

[0041] Figure 19 This is a front view of the force diagram of the thrust testing device in this invention;

[0042] Figure 20 This is a left view of the force diagram of the thrust testing device in this invention;

[0043] Figure 21 This is a top view of the force diagram of the thrust testing device in this invention;

[0044] Figure 22 This is a schematic diagram of the horizontal forces acting on the horizontal sliding force measuring platform in this invention;

[0045] Figure 23 This is a schematic diagram of the motion of the underwater thruster after deflection angle in this invention;

[0046] Figure 24 This is a schematic diagram of the horizontal forces acting on the underwater thruster after its deflection angle in this invention.

[0047] Figure 25 This is an isometric view of the experimental apparatus of the present invention after removing the automatic center of gravity adjustment device;

[0048] Figure 26 This is an isometric view of the experimental apparatus of the present invention after the automatic center of gravity adjustment device has been removed. Detailed Implementation

[0049] Example 1

[0050] like Figure 1 As shown, this embodiment of a thrust testing device for an adjustable-center-of-gravity underwater thruster includes a test pool 74, a rotary arm assembly 71 that drives the underwater thruster 73 to rotate circumferentially in the test pool, and a thrust testing device 72 disposed between the rotary arm assembly and the underwater thruster 73. The underwater thruster 73 is installed below the thrust testing device 72, and the thrust testing device 72 is installed on the crossbeam of the rotary arm assembly 71. The rotary arm assembly 71 drives the thrust testing device 72 and the underwater thruster 73 to perform continuous circumferential motion within the test pool 74.

[0051] like Figure 2 As shown, the thrust testing device 72 mainly consists of an angle adjustment device 75, a horizontal sliding force measuring platform 76, and a center of gravity adjustment mechanism 77. The angle adjustment device 75 can adjust the angle between the direction of motion of the thruster 73 and the direction of thrust. The horizontal sliding force measuring platform 76 can measure the thrust of the underwater thruster 73 in the horizontal direction. The center of gravity adjustment mechanism 77 can adjust the position of the center of gravity of the horizontal thruster 73 within the horizontal sliding force measuring platform.

[0052] like Figure 3 and 4As shown, the rotating platform connecting plate 16 of the angle adjustment device 75 is connected to the crossbeam 48 by bolts. The rotating platform base 17 has countersunk holes at its four corners, which are fixed to the rotating platform connecting plate 16 by bolts. The inner ring of the rotating platform base 17 mates with the outer ring of the inner baffle 33 of the horizontal slide. Bolts are used to pass through the countersunk holes of the connecting plate 64 and fix it to the inner baffle 33 of the horizontal slide. A fixing boss is provided on the outside of the rotating body of the inner baffle 33 of the horizontal slide. The rotating platform base 17 is sleeved on the outside of the rotating body and located between the rotating body and the fixing boss. The locking ring 62 is sleeved on the outside of the fixing boss of the inner baffle 33 of the horizontal slide. The inner ring of the locking ring 62 and the outer ring of the fixing boss of the inner baffle 33 of the horizontal slide rotate relative to each other. The locking seat 18 is fixed to the locking ring 62 by bolts. The side of the locking ring 62 has a hole with internal threads. The locking screw 19 is threaded to the locking seat 18. The end of the locking screw 19 passes through the inner ring 62. After the hole is closed, the inner baffle 33 of the horizontal slide is fixed to the outer ring of the boss. After loosening the locking screw 19, the inner baffle 33 of the horizontal slide and the rotating platform base 17 can rotate relative to each other. Tighten the locking screw 19 to fix the locking screw 19 and the rotating worktable 33. The left-turning fine adjustment screw 20 and the right-turning fine adjustment screw 21 fixed on the rotating platform base 17 can abut against the left and right sides of the locking seat 18 to fix the rotating platform base 17 and the rotating worktable 33. By adjusting the left-turning fine adjustment screw 20 and the right-turning fine adjustment screw 21, the angle of the locking seat 18 relative to the horizontal rotating platform base 17 can be finely adjusted, thereby finely adjusting the angle between the rotating worktable 33 and the rotating platform base 17. The upper baffle 25 of the horizontal slide and the rotating worktable 33 are fixed together by bolts.

[0053] like Figures 5 to 9 As shown, the horizontal sliding baffle 25 of the horizontal sliding force measuring table 76 has a through hole and is fixed together with the countersunk hole on the rotary worktable 33 by bolts. A horizontal sliding baffle 2 is welded to the front and rear ends of the horizontal sliding baffle 25. A groove is opened in the center of the horizontal sliding baffle 25. The horizontal sliding inner baffle 23 is inserted into the groove of the horizontal sliding baffle 25 and welded for fastening. The plane of the horizontal sliding inner baffle 23 is perpendicular to the plane of the horizontal sliding baffle 25. I-beams 32 are set on both sides of the horizontal sliding baffle 25. The horizontal sliding inner baffle 23 is located between the two I-beams 32, and the horizontal sliding inner baffle 23 and the two I-beams 32 extend in the same direction. The horizontal sliding baffle 2 is located at both ends of the horizontal sliding inner baffle 23 and the two I-beams 32.

[0054] Bolts connect the horizontal slide lower baffle 5 to the roller base 4 through the through hole on the horizontal slide lower baffle 5 and the internal thread of the roller base 4. The roller base 4 has through holes on its edge. The roller base 4 and a pair of roller bearing seats 3 are fixed together with bolts. The roller 14 passes through the bearing of the roller bearing seat 3. The roller 14 is locked by tightening the set screw of the roller bearing seat 3. The front and rear ends of the I-beam 32 are clamped by these four sets of rollers. At this point, the horizontal slide lower baffle 5 is limited to the horizontal plane.

[0055] Two through holes are opened at both ends of the transverse roller support frame 15. One end is connected to the side through hole of the roller base 4 by bolts, and the other end is connected to the through hole on the roller bearing seat by bolts. The roller 14 is fixed on the roller bearing seat by set screws. Due to the presence of the roller 14, the inner baffle 23 of the horizontal slide is clamped in the middle, so the lower baffle 5 of the horizontal slide can only move back and forth along the axis of the I-beam 32 in the horizontal plane.

[0056] A through hole is formed in the middle of the lower baffle 5 of the horizontal slide. Bolts pass through the through hole in the lower baffle 5 and the through hole on the bottom surface of the rear baffle 29 of the tension / compression sensor to fasten them together. The protruding part of the rear baffle 29 of the tension / compression sensor has external threads, and the internal threads of the S-shaped tension / compression sensor 30 mate with the rear baffle 29 of the tension / compression sensor. The protruding part at the lower end of the front baffle 31 of the tension / compression sensor also has external threads that mate with the internal threads of the S-shaped tension / compression sensor 30. A through hole is formed on the bottom plate of the front baffle 31 of the tension / compression sensor, and a through hole is also formed in the middle of the horizontal slide baffle 2. The two are fastened together with bolts. At this time, the S-shaped tension / compression sensor 30 can withstand the tangential force between the lower baffle 5 and the upper baffle 25 of the horizontal slide.

[0057] like Figure 10 and Figure 11As shown, the center of gravity adjustment mechanism 77 includes a first lead screw slide and a second lead screw slide. Both the first and second lead screw slides include a slide base plate 6, a lead screw 28 mounted on the slide base plate 6, a lead screw slide drive motor 13 that drives the lead screw 28 to rotate, and a slider 27 threadedly connected to the lead screw. The slide base plate 6 of the first lead screw slide has a threaded hole, and bolts pass through a through hole in the lower baffle 5 of the horizontal slide and connect to the threaded hole in the slide base plate 6. The upper part of the lead screw slide side plate 7 of the lead screw slide has a countersunk hole, which is connected to the lead screw slide base plate 6 by bolts. The two ends of the lead screw 28 are supported by the lead screw slide bearing 35. The external thread of the lead screw 28 mates with the internal thread of the nut 26, allowing the nut 26 to move along the axis. The nut 26 has through holes around its perimeter, which are connected to the internal thread of the nut slider 27 via bolts. The lower surface of the slider support plate 8 has countersunk holes, and the lower surface of the nut slider 27 is fastened to it with screws. The surface of the slide rail 10 has countersunk holes, which are fixed to the slide rail frame 61 via bolts. The slide rail frame 61 and the lead screw slide base plate 6 are connected by bolts. The slider 60 mates with the slide rail 10, allowing for movement. For sliding, the upper surface of the slider 60 has a threaded hole, which can be fixed to the slider support plate 8 by bolts. The end of the lead screw 28 is connected to the main shaft of the lead screw slide drive motor 13 by a coupling 12. The lead screw slide drive motor 13 can drive the pusher to move along the axial direction of the lead screw 28. In order to realize the adjustment of the center of gravity of the pusher by moving in the horizontal plane, two pairs of lead screw slides are used to cross and are connected by the slide connecting plate 34. The upper surface of the first lead screw slide and the slider support plate 8 has a threaded hole, which is connected to the slide base plate 6 of the second lead screw slide by bolts.

[0058] like Figure 12 and Figure 13 As shown, its angle adjustment device consists of a rotating platform base 17, a worktable, a base, a handle, a locking screw, a fine-tuning bolt, etc. When using the angle adjustment device, first loosen the locking screw 19 to release the lock, then turn the rotating handle 1 to observe the scale on the worktable. When it is about to reach the target scale, adjust the left fine-tuning screw 20 and the right fine-tuning screw 21 for fine-tuning. Finally, tighten the locking screw 19 to adjust the direction of the test pusher.

[0059] The kinematic pair of the horizontal sliding platform consists of two I-beams 23 and eight rollers 14. The rollers 14 are connected to the roller base 4 through the roller bearing seat 3, so that the lead screw slide base plate 6 can slide back and forth along the end face of the I-beams 23. The baffle 25 on the horizontal slide has a bolt hole in the center, which can be connected to the platform base 17 of the manual angle adjustment device through bolts.

[0060] The center of gravity adjustment mechanism consists of two lead screw slide base plates 6 that are crossed at 90 degrees and then fixed together with bolts. The underwater thruster is fixed to the thruster plate 9 by a column. The thruster plate has bolt holes, and the thruster and the center of gravity adjustment device are fixed together with bolts. The lower plate 5 of the horizontal sliding platform has bolt holes, and the lead screw slide base plate 6 can be fixed to it with bolts.

[0061] like Figure 14 , Figure 15 , Figure 16 As shown, the rotating arm assembly 71 includes a vertically upward extending column 59 fixed in the middle of the test water tank 74, a lower hinge 57 rotatably connected to the column 59, a crossbeam 48 hinged to the lower hinge 57, an internal gear 42 positioned at the end of the crossbeam 48, and an internal gear drive motor 50 driving the internal gear 42 to rotate. The lower end of the column 59 is welded to the surface of the column base plate 24, and the strength between the two is reinforced by welding the column sheet metal 22. The upper end surface of the column 59 has a threaded hole, and both the inner and outer rings of the column bearing 58 have threaded holes. The outer ring of the column bearing 58 is fastened to the lower hinge 57 by bolts. The lower hinge 57 and the upper hinge 55 are connected by a hinge shaft 56, so the upper hinge 55 can rotate around the lower hinge 59. Hinge 57 rotates. The right end of the upper hinge 55 and the right surface of the I-beam 54 both have through holes. The two are fastened together by bolts. The other end of the I-beam 54 is connected to the crossbeam 48 by welding. The connection strength between the two is strengthened by welding the crossbeam reinforcing rib 53. The other end of the crossbeam 48 is also connected to the cantilever plate 36 by welding. To strengthen the connection strength between the two, an internal gear motor seat 51 is added between them. The internal gear motor seat 51 has through holes around its perimeter. The crossbeam 48 has threaded holes, which can be used to connect the two by bolts. The right end of the internal gear motor seat 51 has a through hole, and the surface of the cantilever plate 36 also has through holes. The two are connected by bolts. The right end of the cantilever plate 36 has through holes that mate with the through holes of the upper cantilever roller bearing seat 37 and the lower cantilever roller bearing seat 40, respectively. The two upper cantilever roller bearing seats 37 and the lower cantilever roller bearing seat 40 are connected to the cantilever plate 36 by bolts. The shaft of the upper cantilever roller 38 passes through the bearing inner hole of the upper cantilever roller bearing seat 37 and is fixed by set screws. The lower cantilever roller 39 and the lower cantilever roller bearing seat 40 are also fixed by set screws. A cantilever support frame 41 is sandwiched between the upper cantilever roller 38 and the lower cantilever roller 39. The upper cantilever roller 38 can roll along the upper surface of the cantilever support frame 41, thereby allowing the crossbeam 48 to rotate in the horizontal plane.

[0062] The rotation of the cantilever device is achieved by a set of internally meshing gears (internal gear 42 and external gear 52) on the right side of the crossbeam. The internal gear drive motor 50 at the upper end of the crossbeam is connected to the gear shaft 49 by a key. The upper and lower ends of the gear shaft 49 pass through the inner ring of the bearing in the bearing seat 46. The lower surface of the bearing seat 46 is connected to the lower support plate 43 of the bearing seat by bolts. The lower support plate 43 of the bearing seat has a through hole on its left side. The upper and right surfaces of the bearing seat side bracket 47 have through holes respectively. The bearing seat side bracket 47 and the lower support plate 43 of the bearing seat are connected by bolts. The bearing seat side bracket 47 and the crossbeam 48 are connected by bolts. The lower surface of the external gear is supported by the flange of the column of the outer frame of the pool. The upper surface of the external gear is pressed by the lower surface of the U-shaped guide rail groove cantilever support frame 41. The cantilever support frame 41 is fixed to the outer frame of the pool 44 by set screws. The inner wall 45 of the pool is fastened to the outer frame of the pool 44 by screws.

[0063] Example 2

[0064] In this embodiment, an experimental method for a thrust experimental device includes the following steps:

[0065] Step 1: Determine the test parameters, including the propeller rotation speed of the underwater thruster, the angular velocity of the underwater thruster in the test pool, and the angle between the thrust direction and the velocity direction of the underwater thruster;

[0066] Step 2: Determine the center of gravity of the underwater thruster in the thrust testing device based on the test parameters;

[0067] Step 3: Adjust the center of gravity of the underwater thruster in the thrust testing device;

[0068] Step 4: Conduct the test according to the test parameters.

[0069] Determining the center of gravity of the underwater thruster in the thrust testing device includes the following steps:

[0070] Step 1: As Figure 17 , Figure 18 As shown, the propeller blade rotation speed is set to ω. The propeller is suspended below the crossbeam and driven by the cantilever water tank drive motor to rotate the propeller counterclockwise around the water tank with a rotational angular velocity of Ω. After the propeller is rotated once by the test water tank, the propeller rotates once counterclockwise around the Z-axis with a rotational angular velocity equal to the rotational angular velocity of the crossbeam Ω.

[0071] Step 2: Perform force analysis on the thruster.

[0072] like Figure 18As shown, the propeller blades rotate at a speed of ω, generating a forward thrust F. The propeller rotor itself rotates at an angular velocity ω about its mass symmetry axis Y. Since the propeller rotates counterclockwise relative to the Z-axis, according to Reichai's theorem, a gyroscopic torque M will be generated. I gyro torque M I direction such as Figure 18 As shown, the gyro torque M I The size is M I =J Z ωΩ.

[0073] like Figure 19 As shown, due to the thruster rotating around the column, a centrifugal force F will be generated during the test. an If the mass of the thruster is m, and the horizontal distance between the thruster's center of gravity and the column is R, then the magnitude of the centrifugal force is F. an =Ω 2 ·R·m

[0074] like Figure 20 As shown, the thrust F generates a torque about the X-axis, and the magnitude of the torque is F·H.

[0075] like Figure 19 , Figure 20 , Figure 21 As shown, the supporting forces of the four pairs of rollers on the propeller are as follows: F a1 F a2 F a3 F a4 In the vertical direction there is F a1 +F a2 +F a3 +F a4 -mg = 0. Centrifugal force F an and F a1 F a2 A clockwise torque, F, is applied to the Y-axis. a3 F a4 If a counterclockwise torque is applied to the Y-axis, then -F an ·H-(F a1 +F a2 )·A+(F a3 +F a4 A = 0. Gyroscopic torque M I and F a2 F a4 Each generates a counterclockwise torque on the X-axis, F. a1 F a3 If a clockwise torque is applied to the X-axis, then M... I +F·H+(F a2 +F a4 )·B-(F a1 +Fa3 B = 0. Additionally, add constraint F. a1 +F a4 =F a2 +F a3 The above four equations, after transformation, yield the following system of equations:

[0076]

[0077] Solving the system of equations yields the following results:

[0078]

[0079] Tension / compression sensor reading F L = Actual thrust of the propeller F ± Frictional force between the roller and the I-beam F f Frictional force F f =μ·(|F a1 |+|F a2 |+|F a3 |+|F a4 Therefore, there is a measurement error.

[0080] Step 3: Analyze the magnitude of the measurement error.

[0081] (1) In and Under the given conditions, then F a2 <0, F a3 >0,

[0082] like Then F a1 >0, F a4 <0,

[0083] like Then F a1 <0, F a4 >0,

[0084] like Then F a1 >0, F a4 >0,

[0085]

[0086] (2) In and Under the given conditions, then F a1 >0, F a3 >0, F a4 >0,

[0087] like Then F a2 <0, at this time,

[0088] like Then F a2 >0, F f =μmg

[0089] (3) In and Under the given conditions, then F a2 <0, F a3 >0, F a4 >0,

[0090] like Then F a1 >0,

[0091] At this time, F f >μ·mg;

[0092] like Then F a1 <0,

[0093] (4) In and Under the given conditions, then F a1 >0,F a2 <0, F a3 >0,

[0094] like Then F a4 <0,

[0095] like Then F a4 >0, At this time, F f >μ·mg;

[0096] Based on the analysis of the measurement error in this step, the current measurement error is F. f ≥μ·mg.

[0097] Step 4: Determine the center of gravity of the underwater thruster in the test apparatus.

[0098] like Figure 21 , Figure 22 As shown, the center of gravity of the underwater thruster is determined to be within the test apparatus, having moved Xg along the X-axis and Yg along the Y-axis. Based on the force and torque equilibrium conditions, the following system of equations exists.

[0099]

[0100] Solving the system of equations yields the following results:

[0101]

[0102] Based on this result, the position of the underwater thruster's center of gravity within the test apparatus was adjusted as follows:

[0103]

[0104] Then there is F f =μ·mg

[0105] Comparing the results of steps 3 and 4, it can be seen that by adjusting the position of the underwater thruster's center of gravity within the measuring device, the frictional force F between the roller and the I-beam is increased. f By consistently maintaining the value at its minimum μ·mg, the error range of thrust measurement results can be reduced, thereby improving measurement accuracy.

[0106] like Figure 22 As shown, in the horizontal plane, the centrifugal force F generated during the test due to rotation... an Support force F generated by the horizontal roller a5 and F a6 If the equilibrium is achieved in the X direction, then: F an =F a5 +F a6 ,F an and F a5 It generates a clockwise torque on the Z-axis, F a6 If F produces a counterclockwise torque on the Z-axis, then: F an ·Y g +F a5 ·D=F a6 ·D+F·X g

[0107] Combining the above two equations, we can obtain the following system of equations:

[0108]

[0109] The solution yields the following results:

[0110]

[0111] To ensure that the frictional force generated by the lateral rollers does not increase during the test, F a5 and F a6 All should be greater than zero, that is Therefore, D should be increased as much as possible in order to increase X. g Y g The adjustment range.

[0112] like Figure 23 and Figure 24As shown, after adjusting the manual adjustment mechanism, the thruster and the horizontal sliding force measuring platform will rotate together by an angle θ. At this time, the angle between the thruster's velocity V and the thrust F is θ. an Decompose the components sequentially along the X and Y axes to obtain component F. anX =F an ·cosθ and F anY =F an ·sinθ, such as Figure 24 As shown in F anX and F a1 F a2 The clockwise torque on the Y-axis is produced by gravity G and F. a3 F a4 It produces a counterclockwise torque on the Y-axis, therefore: -F an ·cosθ·h-(F a1 +F a2 )·A+(F a3 +F a4 )·A+mg·X g =0, such as Figure 24 As shown: M I Thrust F, F anY F a2 F a4 It will produce a counterclockwise torque on the X-axis, F a1 F a3 Gravity G will produce a clockwise torque on the X-axis, then: M I +(F+F an ·sinθ)·H+(F a2 +F a4 )·B-(F a1 +F a3 )·B-mg·Y g =0

[0113] Therefore, the following system of equations can be established:

[0114]

[0115] Solving the system of equations yields the following results:

[0116]

[0117] Tension / compression sensor reading F L = Actual thrust of the thruster F + Centripetal force component along the Y-axis F an • sinθ± the frictional force F between the roller and the I-beam f Frictional force F f =μ·(|F a1 |+|F a2 |+|F a3 |+|Fa4 |), therefore, this invention patent has F f =μ·(|F a1 |+|F a2 |+|F a3 |+|F a4 |) measurement error.

[0118] Based on this result, the position of the underwater thruster's center of gravity within the test apparatus was adjusted as follows:

[0119]

[0120] Then there is F f =μ·mg

[0121] Example 3

[0122] During the rotational motion of the thruster around the column, in addition to the influence of the thruster's own mass m, the center of gravity adjustment mechanism also has a mass m2. This mass will adversely affect the test. To solve this problem, the structure is simplified, such as... Figure 25 and Figure 26 As shown: After removing the center of gravity adjustment device, the pusher can be installed in multiple positions on the force measuring table due to a series of openings in the lower plate of the sliding force measuring table. Before starting the test, the eccentricity X is calculated from the determined rotational speed and eccentricity angle. g and Y g Installing the thruster in this position reduces test error.

Claims

1. A thrust experimental device for an underwater thruster with an adjustable center of gravity, characterized in that, The test pool (74) includes a rotating arm assembly (71) that drives the underwater thruster (73) to rotate circumferentially in the test pool, and a thrust testing device (72) set between the rotating arm assembly and the underwater thruster (73). The thrust testing device (72) includes a horizontal sliding force measuring platform (76) and a center of gravity adjustment mechanism (77). The horizontal sliding force measuring platform includes a horizontal sliding upper baffle (25) connected to the rotating arm assembly (71), a slide rail set on the horizontal sliding upper baffle (25), a horizontal sliding lower baffle (5), a roller (14) set on the horizontal sliding lower baffle (5), and a tension and compression sensor (30) set between the horizontal sliding upper baffle (25) and the horizontal sliding lower baffle (5). The roller (14) moves along the slide rail on the horizontal sliding upper baffle (25), and the slide rail extends along the thrust direction of the underwater thruster (73). The center of gravity adjustment mechanism (77) includes a first lead screw slide and a second lead screw slide. Both the first lead screw slide and the second lead screw slide include a slide base plate (6), a lead screw (28) set on the slide base plate (6), a lead screw slide drive motor (13) for driving the lead screw (28) to rotate, and a slider (27) threadedly connected to the lead screw. The slide base plate (6) of the first lead screw slide is fixedly connected to the horizontal slide lower baffle (5). The slide base plate (6) of the second lead screw slide is fixedly connected to the slider (27) of the first lead screw slide. The slider (27) of the second lead screw slide is fixedly connected to the underwater thruster (73). The extension directions of the lead screws (28) of the first lead screw slide and the second lead screw slide are perpendicular to each other. The thrust testing device (72) further includes an angle adjustment device (75), which includes a rotating platform connecting plate (16) connected to the rotating arm assembly (71), a rotating platform base (17) fixedly connected to the rotating platform connecting plate (16), a rotating worktable (33) cooperating with the rotating platform base (17), a locking ring (62) sleeved on the outside of the rotating worktable (33), a locking seat (18), and a locking screw (19) threadedly connected to the locking seat (18). The rotating platform base (17) and the rotating worktable (33) rotate relative to each other. The rotating worktable (33) is fixedly connected to the baffle (25) on the horizontal slide. The thrust direction of the underwater thruster (73) is adjusted by rotating the rotating worktable (33). The end of the locking screw (19) abuts against the outer ring of the rotating worktable (33). The locking screw (19) is positioned on the rotating platform base (17). Tightening the locking screw (19) fixes the locking ring (62), the rotating platform base (17) and the rotating worktable (33).

2. The thrust experimental apparatus according to claim 1, characterized in that, The angle adjustment device (75) further includes a left-turn fine-tuning screw (20), a right-turn fine-tuning screw (21), and a fine-tuning support. The left-turn fine-tuning screw (20) and the right-turn fine-tuning screw (21) are threadedly connected to both sides of the fine-tuning support. The adjusting end of the locking screw (19) is located between the left-turn fine-tuning screw (20) and the right-turn fine-tuning screw (21). The left-turn fine-tuning screw (20) and the right-turn fine-tuning screw (21) abut against both sides of the adjusting end of the locking screw (19). Adjusting the left-turn fine-tuning screw (20) and the right-turn fine-tuning screw (21) finely adjusts the rotary table (33) through the locking screw (19).

3. The thrust experimental apparatus according to claim 1, characterized in that, The slide rail set on the baffle (25) of the horizontal slide platform includes I-beams (32) on both sides of the bottom surface of the baffle (25) of the horizontal slide platform and an inner baffle (23) of the horizontal slide platform located in the middle of the bottom surface of the baffle (25) of the horizontal slide platform. Roller bases (4) are set on both sides of the lower baffle (5) of the horizontal slide platform. Several first roller groups are set on the roller bases (4). The first roller group includes two rollers (14) symmetrically arranged. The roller axes of the two rollers of the first roller group are parallel to the plane of the baffle (25) of the horizontal slide platform. The bottom plate of the I-beams (32) Located between the two rollers of the first roller group, the two rollers of the first roller group move along the I-beam (32); several second roller groups are arranged in the middle of the lower baffle (5) of the horizontal slide, the second roller group includes two symmetrically arranged rollers (14), the roller shafts of the two rollers of the second roller group are perpendicular to the plane of the upper baffle (25) of the horizontal slide and parallel to the plane of the inner baffle (23) of the horizontal slide, the inner baffle (23) of the horizontal slide is located between the two rollers of the second roller group, and the two rollers of the second roller group move along the inner baffle (23) of the horizontal slide.

4. The thrust experimental apparatus according to claim 3, characterized in that, The tension / compression sensor (30) is an S-shaped tension / compression sensor.

5. The thrust experimental apparatus according to claim 4, characterized in that, The first lead screw slide and the second lead screw slide also include an adjusting slide rail (10) fixedly connected to the slide base plate (6), an adjusting slider (60) that slides relative to the adjusting slide rail (10), and a slider support plate (8) fixedly connected to the adjusting slider (60). The slider (27) is fixedly connected to the slider support plate (8).

6. The thrust experimental apparatus according to claim 1, characterized in that, The rotating arm assembly (71) includes a column (59) fixed in the middle of the test pool (74) extending vertically upward, a lower hinge (57) rotatably connected to the column (59), a crossbeam (48) hinged to the lower hinge (57), an internal gear (42) positioned at the end of the crossbeam (48), and an internal gear drive motor (50) that drives the internal gear (42) to rotate. The test pool (74) is circumferentially provided with an external gear (52) that meshes with the internal gear (42). The internal gear drive motor (50) is fixedly connected to the crossbeam (48). By driving the internal gear (42) to rotate, the crossbeam (48) rotates around the column (59). The thrust testing device (72) is connected to the crossbeam (48).

7. The thrust experimental apparatus according to claim 6, characterized in that, The test pool (74) is circumferentially provided with a cantilever support frame (41), and the end of the crossbeam (48) is provided with a third roller group. The third roller group includes a symmetrically arranged upper cantilever roller (38) and lower cantilever roller (39). The roller axes of the upper cantilever roller (38) and the lower cantilever roller (39) are parallel to the extension direction of the crossbeam (48). The top plate of the cantilever support frame (41) is located between the upper cantilever roller (38) and the lower cantilever roller (39). The upper cantilever roller (38) and the lower cantilever roller (39) move along the cantilever support frame (41).

8. An experimental method for the thrust experimental apparatus of claim 1, characterized in that, Includes the following steps: Step 1: Determine the test parameters, including the propeller rotation speed of the underwater thruster, the angular velocity of the underwater thruster in the test pool, and the angle between the thrust direction and the velocity direction of the underwater thruster; Step 2: Determine the center of gravity of the underwater thruster in the thrust testing device based on the test parameters; Step 3: Adjust the center of gravity of the underwater thruster in the thrust testing device; Step 4: Conduct the experiment according to the test parameters.

9. The experimental method according to claim 8, characterized in that, The formula for calculating the center of gravity position of the underwater thruster in the thrust testing device is as follows: in, Let X be the distance from the center of gravity of the underwater thruster to the center of the horizontal sliding force measuring platform along the X-axis. This is the distance from the center of gravity of the underwater thruster along the Y-axis to the center of the horizontal sliding force measuring platform. The angular velocity of the underwater thruster in the test pool. The horizontal distance from the center of gravity of the underwater thruster to a fixed point on the underwater thruster. This is the distance from the center of gravity of the underwater thruster along the Z-axis to the center of the horizontal sliding force measuring platform. The angle between the thrust direction and the velocity direction of the underwater thruster. Let be the distance along the Y-axis from the point of application of the supporting force on the horizontal sliding force measuring platform to the center of the horizontal sliding force measuring platform. Let X be the distance from the point of application of the supporting force on the horizontal sliding force measuring platform along the X-axis to the center of the horizontal sliding force measuring platform. It is the acceleration due to gravity. Let Z be the moment of inertia of the thruster rotor about the Z-axis. The rotational speed of the underwater propeller blades. For the mass of the underwater thruster, This is the thrust of the underwater propulsion device.

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