Underwater propeller swing motion simulation experiment device and swing amplitude adjusting method thereof

Abstract

The invention relates to an underwater propeller swing motion simulation experiment device and a swing amplitude adjusting method thereof, the underwater propeller swing motion simulation experiment device comprises an experiment pool, the experiment pool is provided with a pool frame and a cross beam, and the cross beam is provided with a swing device through a fastener; comprising a top seat, a top shaft is installed below the top seat through a bearing in a supporting mode, the top shaft is sleeved with an outer shaft, a left rotating frame and a right rotating frame are installed at the two ends of the outer shaft through fasteners respectively, a pitching inertia adjusting module is fixed to the bottom of the outer shaft, and middle plates are fixed to the bottoms of the left rotating frame and the right rotating frame at the same time; a bearing base is arranged below the middle plate, a groove is formed in the upper portion of the middle plate, a pair of crossed roller bearings is installed in the groove, the lower middle portion of the connecting middle shaft is installed on the inner sides of the crossed roller bearings, the upper portion of the connecting middle shaft is fixed to the bottom face of the middle plate, and the bearing base and the connecting middle shaft can rotate relative to each other. A yawing inertia adjusting module is fixedly installed below the bearing base, and the yawing inertia adjusting module and the bearing base are perpendicular to each other in the spatial position. The structure is simple, control is sensitive, and energy utilization rate is high.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater propellers, in particular to an underwater propeller swing motion simulation experimental device and a swing amplitude adjustment method thereof. Background Art

[0002] An underwater propeller is a power device that generates thrust through rotating blades, enabling underwater equipment to move through the water. Underwater propellers are widely designed and applied, and their operating principles and structures vary depending on the application scenario. Underwater propellers used in underwater robots offer many advantages, including high efficiency, precise control, strong adaptability, and versatility. These advantages have led to their widespread application in fields such as oil and gas extraction, submarine cable laying, and ocean exploration and scientific research. During navigation, underwater robots are affected by external disturbances such as water currents, eddies, water pressure, and salinity, as well as internal factors, causing them to experience oscillatory motions such as pitch and bow roll, which in turn cause the underwater propeller to oscillate. To evaluate the stability and reliability of underwater propellers under oscillatory motion, a oscillatory motion simulation experimental device for underwater propellers is required.

[0003] For example, publication number CN117232881A discloses an underwater propeller multi-posture motion simulation experimental device and experimental method. In the disclosed experimental device, the first driving member controls the forward and backward movement of the underwater propeller, the supporting trolley controls the left and right movement of the underwater propeller, and the second driving motor controls the rotational movement of the underwater propeller; the servo adjusts the tilt angle of the underwater propeller by controlling the tilt angle of the electric push rod, and cooperates with the forward and backward movement, left and right movement, and rotation to form a simulation of the underwater propeller multi-posture motion.

[0004] For example, publication number CN113982809B discloses a turbine roll / pitch simulation experimental device and its control method. It uses a mechanical device to control the simulation experiment, which can more accurately and completely simulate high-frequency interference such as waves and turbulence. Different driving mechanisms are used to simulate the roll / pitch motion respectively, which is conducive to achieving the optimal distribution of driving force.

[0005] Both devices can realize the swinging motion of the underwater propeller. The motion of each degree of freedom of the two devices is driven by the corresponding electric motor. In the process of the electric motors of the two devices driving the corresponding mechanisms to swing the underwater propellers, the underwater propellers also rely on the rotation of their own blades to generate corresponding thrust. The driving force of the electric motor interacts with the thrust of the underwater propeller, which not only affects the swinging motion, but also easily causes damage to the experimental device, and at the same time, causes energy waste. In addition, the patent "A hydraulic turbine roll / pitch simulation experimental device and its control method" sets a torsion spring series mechanism, and adjusts the overall torsional stiffness of the mechanism by controlling the effectiveness and failure of each torsion spring in the mechanism, thereby achieving a resonance effect and effectively reducing the maximum driving force during the swinging process. However, the torsion spring series mechanism is relatively complex and can only achieve discrete adjustment of the torsional stiffness. Summary of the Invention

[0006] In view of the shortcomings of the above-mentioned existing production technology, the applicant provides an underwater thruster swing motion simulation experimental device and a swing amplitude adjustment method thereof, so that the device has a simple structure, sensitive control and high energy utilization rate.

[0007] The technical solutions adopted in the present invention are as follows:

[0008] An underwater propeller swing motion simulation experimental device includes an experimental water pool, the experimental water pool includes a water pool frame, a crossbeam is provided on the water pool frame, and a swing device is installed on the crossbeam through a fastener;

[0009] The structure of the swing device is as follows: it includes a top seat, a top shaft is installed under the top seat through a bearing support, an outer shaft is sleeved on the outside of the top shaft, the left rotating frame and the right rotating frame are respectively installed on both ends of the outer shaft through fasteners, the bottom of the outer shaft is fixed with a pitch inertia adjustment module, the bottom of the left rotating frame and the right rotating frame are fixed with an intermediate plate at the same time, a bearing base is provided under the intermediate plate, a groove is provided above the bearing base, a pair of cross roller bearings are installed in the groove, the middle and lower part of the connecting middle shaft is installed on the inner side of the cross roller bearing, the upper part of the connecting middle shaft is fixed to the bottom surface of the intermediate plate, and the bearing base and the connecting middle shaft can rotate with each other;

[0010] A bow inertia adjustment module is fixedly installed below the bearing base, and the bow inertia adjustment module and the pitch inertia adjustment module are perpendicular to each other in space.

[0011] As a further improvement of the above technical solution:

[0012] The cross section of the top seat is a "π"-shaped structure.

[0013] The left bearing and the right bearing are respectively placed in the two holes below the top seat. The top shaft and the top seat are connected through the left bearing and the right bearing so that the top shaft and the top seat can rotate relative to each other. The left shaft uses a retaining ring to axially position the left bearing, and the right shaft uses a retaining ring to axially position the right bearing.

[0014] The cross section of the outer shaft is a transverse I-shaped structure.

[0015] The bearing base is a rectangular parallelepiped structure.

[0016] A torsion spring is installed between the intermediate plate and the bearing base.

[0017] The structure of the pitch inertia adjustment module is as follows: it includes a pitch screw, and there is a shaft at each end of the pitch screw, the shaft length of the left end is greater than that of the right end, the leftmost side of the shaft at the left end is used to connect with the pitch coupling, and the shaft at the right end is only connected to the pitch right end cover; the pitch screw is installed with a pitch left mass block and a pitch right mass block of the same structure, and also includes a pitch screw base, the bottom of the pitch screw base is fixed with a pitch slide rail, and the pitch left mass block and the pitch right mass block slide along the pitch slide rail; the left end of the pitch coupling is connected to the motor shaft, the pitch motor is fixed to the leftmost end of the pitch screw base by a fastener, and the pitch right end cover is fixed to the rightmost end of the pitch screw base by a fastener.

[0018] The pitch screw is provided with two sections of threads with the same shape and size and opposite directions.

[0019] The structure of the bow inertia adjustment module is as follows: it includes a bow screw base and a bow screw, a bow slide rail is installed on the bottom surface of the bow screw base, the bow screw has two sections of threads with the same shape and size and opposite directions, the bow motor is fixed on the leftmost end of the bow screw base, and the bow right end cover is fixed on the rightmost end of the bow screw base; the right end of the left bow nut passes through the middle part of the left bow mass block, and the left end of the right bow nut passes through the middle part of the right bow mass block, the left bow nut and the right bow nut are respectively installed on the two sections of threads in opposite directions of the bow screw and are symmetrical about the intersection of the two sections of reverse threads, and the left bow mass block and the right bow mass block match the bow slide rail.

[0020] A method for adjusting the swing amplitude of an underwater propeller swing motion simulation experimental device includes the following operating procedures:

[0021] Step 1: Set the pitch angle θ1 according to the experimental requirements, express the pitch angular velocity and pitch angular acceleration, and then obtain the differential equation of the underwater robot's pitch drive based on the pitch force analysis, and then calculate the required torque for the underwater robot's pitch.

[0022] Step 2: According to J1ω1 2-m1gl1=0, adjust the pitch and swing inertia of the underwater robot. Assume that the pitch left mass block and the pitch right mass block are initially located in the center of their respective strokes, and the distance from the vertical line of the swing device is r 10 , the pitching inertia of the underwater robot at this time is J 10 After the positions of the pitch left mass block and the pitch right mass block are synchronously adjusted, the distance from the vertical line of the swing device is r1, which represents the pitch swing inertia J1 of the underwater robot. Find r1;

[0023] Step 3: According to the mapping relationship between the underwater propeller thrust T and the underwater propeller speed ω0, the propeller speed ω0 is calculated, and the propeller is controlled to run at the speed ω0;

[0024] Step 4: Calculate the gyroscopic torque M2 generated by the underwater propeller motor and blade components during rotation;

[0025] Step 5: Based on the calculation result M2 in the fourth step and the frequency retention characteristics of the linear system, let the bow swing angle θ2 be expressed as the bow swing angular velocity and angular acceleration, and then perform bow swing force analysis. According to the differential equation of the underwater robot's bow swing drive, the underwater robot's bow swing amplitude A2 and yaw balance angle θ when the underwater robot's bow swing amplitude reaches its maximum value can be calculated. 20 ;

[0026] Step 6: The torque required for the underwater robot's bow swing reaches the minimum value, and the underwater robot's bow swing inertia is adjusted. Assume that the bow left mass block and the bow right mass block are initially located at the center of their respective strokes, and the distance from the vertical line of the swing device is r 20 At this time, the bow swing inertia of the underwater robot is J 20 After the positions of the left bow mass block and the right bow mass block are synchronously adjusted, the distance from the perpendicular line of the swing device is r2, which can be expressed as the bow swing inertia J2 of the underwater robot, and r2 can be calculated.

[0027] The beneficial effects of the present invention are as follows:

[0028] The present invention has a compact and reasonable structure and is easy to operate. It uses the thrust generated by the rotation of the underwater propeller's own blades to drive the experimental device to pitch and swing, and uses the gyroscopic torque generated by the rotation of the underwater propeller's own motor, blades and other components to drive the experimental device to swing. The experimental device itself has no power drive mechanism. The present invention fully utilizes the force generated by the underwater propeller, which not only tests its power performance but also drives the experimental device to swing, thereby improving energy utilization. At the same time, it also avoids the interaction between the driving force of the motor and the thrust of the underwater propeller in the known experimental device, thereby protecting the experimental device. In the known method, the resonance effect is achieved by adjusting the torsional stiffness. The patent of the present invention uses the method of adjusting the moment of inertia to achieve the resonance effect, and uses two sets of ball screw modules to adjust the moment of inertia of the device, which can achieve continuous adjustment of the moment of inertia, and has high adjustment efficiency and accuracy. The structure is also relatively simple, easy to build and operate, and convenient to adjust and control.

[0029] The swing amplitude adjustment method of the present invention can maximize the swing motion amplitude under the same thrust conditions of the underwater propeller. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the overall structure of the present invention.

[0031] Figure 2 A schematic structural diagram of the swing device of the present invention.

[0032] Figure 3 A sectional view of the right side view of the swing device of the present invention.

[0033] Figure 4 A sectional view of the upper half of the main view of the present invention.

[0034] Figure 5 A cross-sectional view of the front view of the middle part of the present invention.

[0035] Figure 6 A comparative schematic diagram of the propeller installation forms of the underwater propeller of the present invention.

[0036] Figure 7 Schematic diagram of the pitch and swing force analysis of the present invention.

[0037] Figure 8a Schematic diagram of the bow swing force analysis of the present invention (left).

[0038] Figure 8b Schematic diagram of the bow swing force analysis of the present invention (right).

[0039] Including: 1. Experimental pool; 2. Swing device; 3. Middle plate;

[0040] 11. Pool frame; 12. Beam;

[0041] 201. Top seat; 202. Pitch inertia adjustment module; 203. Yawing inertia adjustment module; 204. Torsion spring; 205. Top shaft; 206. Outer shaft; 207. Retaining ring for left shaft; 208. Retaining ring for right shaft; 209. Left bearing; 210. Right bearing; 211. Crossed roller bearing; 212. Left turret; 213. Right turret; 214. Bearing base; 215. Rear robot mounting frame; 216. Front robot mounting frame; 217. Underwater robot; 218. Underwater thruster; 219. Connecting shaft;

[0042] 31. Pitch motor; 32. Pitch coupling; 33. Pitch left mass block; 34. Pitch right mass block; 35. Pitch left nut; 36. Pitch right nut; 37. Pitch rail;

[0043] 40. Pitch screw; 41. Pitch left end cover; 42. Pitch right end cover; 43. Pitch screw base;

[0044] 51. Bow motor; 52. Bow coupling; 53. Left bow mass block; 54. Right bow mass block; 55. Left bow nut; 56. Right bow nut; 57. Bow slide rail;

[0045] 60. Bow crank screw; 61. Bow crank left end cover; 62. Bow crank right end cover; 63. Bow crank screw base. DETAILED DESCRIPTION

[0046] The specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0047] like Figure 1-8b As shown, the underwater propeller swing motion simulation experimental device of this embodiment includes an experimental pool 1, the experimental pool 1 includes a pool frame 11, a crossbeam 12 is provided on the pool frame 11, and a swing device 2 is installed on the crossbeam 12 through fasteners;

[0048] The structure of the swing device 2 is as follows: it includes a top seat 201, a top shaft 205 is installed below the top seat 201 through a bearing support, an outer shaft 206 is sleeved on the outside of the top shaft 205, and the left rotating frame 212 and the right rotating frame 213 are respectively installed at both ends of the outer shaft 206 by fasteners, the bottom of the outer shaft 206 is fixed with the pitch inertia adjustment module 202, and the bottoms of the left rotating frame 212 and the right rotating frame 213 are fixed with the middle plate 3 at the same time, a bearing base 214 is provided below the middle plate 3, a groove is provided above the bearing base 214, a pair of cross roller bearings 211 are installed in the groove, the middle and lower part of the connecting middle shaft 219 is installed on the inner side of the cross roller bearing 211, the upper part of the connecting middle shaft 219 is fixed to the bottom surface of the middle plate 3, and the bearing base 214 and the connecting middle shaft 219 can rotate with each other;

[0049] A yaw inertia adjustment module 203 is fixedly installed below the bearing base 214 . The yaw inertia adjustment module 203 and the pitch inertia adjustment module 202 are perpendicular to each other in space.

[0050] The cross section of the top seat 201 is a “π”-shaped structure.

[0051] A left bearing 209 and a right bearing 210 are placed inside the two holes below the top seat 201 respectively. The top shaft 205 is connected to the top seat 201 through the left bearing 209 and the right bearing 210, so that the top shaft 205 and the top seat 201 can rotate relative to each other. The left shaft uses a retaining ring 207 to axially position the left bearing 209, and the right shaft uses a retaining ring 208 to axially position the right bearing 210.

[0052] The cross section of the outer shaft 206 is a transverse I-shaped structure.

[0053] The bearing base 214 is a rectangular parallelepiped structure.

[0054] A torsion spring 204 is installed between the middle plate 3 and the bearing base 214 .

[0055] The structure of the pitch inertia adjustment module 202 is as follows: it includes a pitch screw 40, and the left and right ends of the pitch screw 40 respectively have a shaft, the shaft length of the left end is greater than the shaft length of the right end, the leftmost side of the shaft at the left end is used to connect with the pitch coupling 32, and the shaft at the right end is only connected to the pitch right end cover 42; the pitch screw 40 is equipped with a pitch left mass block 33 and a pitch right mass block 34 with the same structure, and also includes a pitch screw base 43, and the bottom of the pitch screw base 43 is fixed with a pitch slide rail 37, and the pitch left mass block 33 and the pitch right mass block 34 slide along the pitch slide rail 37; the left end of the pitch coupling 32 is connected to the motor shaft, the pitch motor 31 is fixed to the leftmost end of the pitch screw base 43 by fasteners, and the pitch right end cover 42 is fixed to the rightmost end of the pitch screw base 43 by fasteners.

[0056] The pitch screw 40 is provided with two sections of threads with the same shape and size but opposite directions.

[0057] The structure of the bow inertia adjustment module 203 is as follows: it includes a bow screw base 63 and a bow screw 60. The bottom surface of the bow screw base 63 is installed with a bow slide rail 57. The bow screw 60 has two sections of threads with the same shape and size and opposite directions. The bow motor 51 is fixed to the leftmost end of the bow screw base 63, and the bow right end cover 62 is fixed to the rightmost end of the bow screw base 63; the bow left screw The right end of the nut 55 passes through the middle part of the left bow mass block 53, and the left end of the right bow nut 56 passes through the middle part of the right bow mass block 54. The left bow nut 55 and the right bow nut 56 are respectively installed on two sections of opposite threads of the bow screw 60 and are symmetrical about the intersection of the two sections of reverse threads. The left bow mass block 53 and the right bow mass block 54 are matched with the bow slide rail 57.

[0058] The swing amplitude adjustment method includes the following steps:

[0059] Step 1: Set the pitch angle θ1 according to the experimental requirements, express the pitch angular velocity and pitch angular acceleration, and then obtain the differential equation of the underwater robot's pitch drive based on the pitch force analysis, and then calculate the required torque for the underwater robot's pitch.

[0060] Step 2: According to J1ω1 2 -m1gl1=0, adjust the pitch and swing inertia of the underwater robot. Assume that the pitch left mass block and the pitch right mass block are initially located in the center of their respective strokes, and the distance from the vertical line of the swing device is r 10 , the pitching inertia of the underwater robot at this time is J 10 After the positions of the pitch left mass block and the pitch right mass block are synchronously adjusted, the distance from the vertical line of the swing device is r1, which represents the pitch swing inertia J1 of the underwater robot. Find r1;

[0061] Step 3: According to the mapping relationship between the underwater propeller thrust T and the underwater propeller speed ω0, the propeller speed ω0 is calculated, and the propeller is controlled to run at the speed ω0;

[0062] Step 4: Calculate the gyroscopic torque M2 generated by the underwater propeller motor and blade components during rotation;

[0063] Step 5: Based on the calculation result M2 in the fourth step and the frequency retention characteristics of the linear system, let the bow swing angle θ2 be expressed as the bow swing angular velocity and angular acceleration, and then perform bow swing force analysis. According to the differential equation of the underwater robot's bow swing drive, the underwater robot's bow swing amplitude A2 and yaw balance angle θ when the underwater robot's bow swing amplitude reaches its maximum value can be calculated. 20 ;

[0064] Step 6: The torque required for the underwater robot's bow swing reaches the minimum value, and the underwater robot's bow swing inertia is adjusted. Assume that the bow left mass block and the bow right mass block are initially located at the center of their respective strokes, and the distance from the vertical line of the swing device is r 20 At this time, the bow swing inertia of the underwater robot is J 20 After the positions of the left bow mass block and the right bow mass block are synchronously adjusted, the distance from the perpendicular line of the swing device is r2, which can be expressed as the bow swing inertia J2 of the underwater robot, and r2 can be calculated.

[0065] Depend on Figure 1 As shown, the specific structure and functions of an underwater propeller swing motion simulation experimental device in this embodiment are as follows:

[0066] It mainly consists of an experimental water pool 1 and a swing device 2.

[0067] The swing device 2 is fixedly connected to the crossbeam 12 of the experimental water pool 1 by bolts.

[0068] The experimental water pool 1 is mainly composed of a water pool frame 11 and a crossbeam 12 .

[0069] The crossbeam 12 is fixed on the top of the pool frame 11 by bolts.

[0070] like Figure 2 、 Figure 3 、 Figure 4 As shown, the swing device 2 is mainly composed of a top seat 201, a pitch inertia adjustment module 202, a bow inertia adjustment module 203, a torsion spring 204, a top shaft 205, an outer shaft 206, a retaining ring 207 for the left shaft, a retaining ring 208 for the right shaft, a left bearing 209, a right bearing 210, a cross roller bearing 211, a left rotating frame 212, a right rotating frame 213, an intermediate plate 3, a bearing base 214, a rear robot fixing frame 215, a front robot fixing frame 216, an underwater robot 217, an underwater thruster 218 and a connecting central shaft 219.

[0071] like Figure 2 、 Figure 3 、 Figure 4As shown, the two holes below the top seat 201 are respectively placed with the left bearing 209 and the right bearing 210, and the top shaft 205 is connected with the top seat 201 through the left bearing 209 and the right bearing 210, so as to enable the top shaft 205 and the top seat 201 to rotate with each other. The left shaft stop ring 207 is used to axially position the left bearing 209, and the right shaft stop ring 208 is used to axially position the right bearing 210. The outer shaft 206 is installed and fixed outside the middle of the top shaft 205, the left end of the outer shaft 206 is connected with the left rotating frame 212 through bolt fixing, the right end is connected with the right rotating frame 213 through bolt fixing, the bottom of the outer shaft 206 is a plane, and is fixedly connected with the pitch inertia adjustment module 202 through a screw. The bottom of the left rotating frame 212 and the right rotating frame 213 is installed and fixed on the middle plate 3, and is fixedly connected through a bolt.

[0072] As shown in Figure 2 , Figure 3 , Figure 4 , Figure 5 shown, the bearing base 214 is a cuboid, and a recess is formed in the top center thereof, and the cross roller bearing 211 is installed and fixed in the recess in the middle of the bearing base 214. The top of the connecting shaft 219 is fixedly installed at the middle position of the bottom of the middle plate 3 through bolt connection, and the middle and lower part of the connecting shaft 219 is installed on the inner side of the cross roller bearing 211, so as to enable the bearing base 214 and the connecting shaft 219 to rotate with each other. The torsion spring 204 is installed between the middle plate 3 and the bearing base 214, the cross roller bearing 211 and the connecting shaft 219 are located inside the torsion spring 204, the top end of the torsion spring 204 is inserted into the small hole in the bottom of the middle plate 3, and the bottom end of the torsion spring 204 is inserted into the small hole in the top of the bearing base 214.

[0073] As shown in Figure 2 , Figure 3 , Figure 4 , Figure 5As shown, the pitch inertia adjustment module 202 primarily comprises a pitch motor 31, a pitch coupling 32, a left pitch mass 33, a right pitch mass 34, a left pitch nut 35, a right pitch nut 36, a pitch guide rail 37, a pitch screw 40, a left pitch end cap 41, a right pitch end cap 42, and a pitch screw base 43. The pitch screw 40 has two threads of identical shape and size, but in opposite directions. Each end of the pitch screw 40 has a shaft, with the shaft at the left end being longer than the shaft at the right end. The leftmost portion of the shaft at the left end is used to connect to the pitch coupling 32, while the shaft at the right end is connected only to the pitch end cap 42. These two threads each account for half of the total length of the pitch screw 40. The left and right pitch masses 33 and 34 are identical in shape and structure, and the pitch guide rail 37 is secured to the shaft by screws. The left end of the pitch coupling 32 is connected to the motor shaft, and the right end is connected to the pitch screw 40. The pitch motor 31 is fixedly mounted to the leftmost end of the pitch screw base 43 by screws. The pitch right end cover 42 is also fixedly mounted to the rightmost end of the pitch screw base 43 by screws. The pitch left end cover 41 is also fixedly mounted to the pitch screw base 43 by screws. The right end of the pitch left nut 35 passes through the middle part of the pitch left mass block 33, and the left end of the pitch right nut 36 passes through the middle part of the pitch right mass block 34. The pitch left nut 35 and the pitch right nut 36 are respectively installed on two opposite sections of the pitch screw 40 and are symmetrical about the intersection of the two opposite sections of the reverse threads. The pitch left nut 35 is fixed on the left side of the pitch left mass block 33 by screws, and the pitch right nut 36 is fixed on the right side of the pitch right mass block 34 by screws. The lower grooves of the pitch left mass block 33 and the pitch right mass block 34 are just stuck on the pitch slide rail 37, and can make it slide relatively smoothly. When the pitch motor 31 rotates, it will drive the pitch screw 40 to rotate through the pitch coupling 32, so that the pitch left nut 35 and the pitch right nut 36 move in the same direction or in opposite directions, so that the pitch left mass block 33 and the pitch right mass block 34 slide in the same direction or in opposite directions along the pitch slide rail 37, thereby changing the pitch motion moment of inertia of the experimental device.

[0074] like Figure 4As shown, the bow inertia adjustment module 203 is mainly composed of a bow motor 51, a bow coupling 52, a left bow mass block 53, a right bow mass block 54, a left bow nut 55, a right bow nut 56, a bow slide rail 57, a bow screw 60, a left bow end cover 61, a right bow end cover 62, and a bow screw base 63, wherein the bow screw 60 has two sections of threads with the same shape and size and opposite directions, and the left and right ends of the bow screw 60 are respectively provided with a shaft, the shaft length of the left end is greater than the shaft length of the right end, the leftmost side of the shaft at the left end is used to connect with the bow coupling 52, and the shaft at the right end is only connected with the right bow end cover 62. These two sections of thread each account for half of the total thread length of the bow screw 60. The left bow mass block 53 and the right bow mass block 54 have identical shapes and structures. The bow slide rail 57 is fixedly mounted and connected via screws. The left end of the bow coupling 52 is connected to the motor shaft, and the right end is connected to the bow screw 60. The bow motor 51 is fixedly mounted to the leftmost end of the bow screw base 63 via screws, and the right bow end cap 62 is fixedly mounted to the rightmost end of the bow screw base 63 via screws. The left bow end cap 61 is also fixedly mounted to the bow screw base 63 via screws. The right end of the left bow nut 55 passes through the middle part of the left bow mass block 53, and the left end of the right bow nut 56 passes through the middle part of the right bow mass block 54. The left bow nut 55 and the right bow nut 56 are respectively installed on two sections of opposite threads of the bow screw 60 and are symmetrical about the intersection of the two sections of reverse threads. The left bow nut 55 is fixed on the left side of the left bow mass block 53 by screws, and the right bow nut 56 is fixed on the right side of the right bow mass block 54 by screws. The lower grooves of the left bow mass block 53 and the right bow mass block 54 are just stuck on the bow slide rail 57, and can make it slide relatively smoothly. When the bow motor 51 rotates, it will drive the bow screw 60 to rotate through the bow coupling 52, so that the bow left nut 55 and the bow right nut 56 move in the same direction or in opposite directions, so that the bow left mass block 53 and the bow right mass block 54 slide in the same direction or in opposite directions along the bow slide rail 57, thereby changing the bow motion moment of inertia of the experimental device.

[0075] like Figure 2 As shown, there are two underwater thrusters 218 symmetrically mounted on the tail of the underwater robot 217. The underwater robot 217 is mounted and fixed to the bottom of the rear robot fixing frame 215 and the front robot fixing frame 216, and is fixedly connected by bolts.

[0076] The propellers of the underwater thrusters 218 are installed in the same direction, that is, they rotate in the same clockwise direction or the same counterclockwise direction. The gyroscopic moments generated by the two underwater thrusters 218 are equal in magnitude and in the same direction, and thus superimposed on each other.

[0077] like Figure 8bAs shown, the propellers of the known underwater propeller 218 are installed in a forward and reverse propeller manner, that is, one propeller rotates clockwise and the other propeller rotates counterclockwise. During the navigation of the underwater robot 217, the gyroscopic torques generated by the two propellers are equal in magnitude and opposite in direction, thereby canceling each other out. Figure 8a As shown, the propellers of the underwater thrusters 218 of this embodiment are installed in the same direction, that is, they rotate in the same clockwise direction or the same counterclockwise direction. The gyroscopic torques generated by the two underwater thrusters 218 are equal in magnitude and in the same direction, and thus superimposed on each other.

[0078] In actual work process:

[0079] The specific swing amplitude adjustment method includes the following steps:

[0080] Step 1: Set the pitching angle to θ1 according to the experimental requirements, and θ1 = A1sinω1t; where A1 is the pitching amplitude, ω1 is the pitching angular frequency, and t is the movement time. The pitching angular velocity is dθ1 / dt = A1ω1cosω1t, and the pitching angular acceleration is d 2 θ1 / dt 2 =-A1ω1 2 sinω1t;

[0081] like Figure 6 As shown in the figure, the pitching and swinging force analysis. The differential equation of the underwater robot's pitching and swinging drive is: Among them, J1 is the pitch moment of inertia of the swing device, C1 is the damping coefficient, l1 is the pitch swing radius, m1 is the overall mass of the underwater robot, g is the acceleration of gravity, and M1 is the driving torque.

[0082] Since θ1 is relatively small, this differential equation can be simplified to:

[0083] The torque required for the pitch and roll of the underwater robot is:

[0084]

[0085] in,

[0086] When J1ω1 2 When -m1gl1 = 0, the torque required for the underwater robot's pitching and swinging reaches its minimum. At this point, cosλ1 = 1, sinλ1 = 0, λ1 = 0, and M1 = A1C1ω1cos(ω1t). Under the same torque conditions, the underwater robot's pitching and swinging amplitude will reach its maximum.

[0087] Step 2: According to J1ω1 2-m1gl1=0, adjust the pitch and swing inertia of the underwater robot to

[0088] like Figure 6 As shown, it is assumed that the pitch left mass block and the pitch right mass block are initially located at the center of their respective strokes, and the distance from the vertical line of the swing device is r 10 At this time, the pitching inertia of the underwater robot is J 10 After the positions of the left and right pitching mass blocks are adjusted synchronously, the distance from the vertical line of the swing device is r1. At this time, the pitching inertia of the underwater robot is J1 = J 10 +2m1(r1 2 -r 10 2 ).Depend on have to, That is, the distance r1 between the position of the pitch left mass block and the pitch right mass block and the vertical line of the swing device is adjusted to

[0089] Step 3: Based on the calculation result in Step 2, M1 = A1C1ω1cos(ω1t). Since the underwater robot in this embodiment has two thrusters installed at its tail, the underwater thruster thrust T is M1 = A1C1ω1cos(ω1t) = 2Tl1, which gives T = A1C1ω1cos(ω1t) / (2l1). Based on the mapping relationship between underwater thruster thrust T and underwater thruster speed ω0, the thruster speed ω0 is calculated, and the thrusters are controlled to operate at speed ω0.

[0090] Take the mapping relationship between the underwater propeller thrust T and the underwater propeller speed ω0 as T=k0ω0 as an example, where k0 is the proportional coefficient. Then we have

[0091] Step 4: Calculate the gyroscopic torque M2 generated by the underwater propeller motor, blades and other components during rotation. The calculation formula is:

[0092]

[0093] Where J0 is the moment of inertia of the underwater thruster around its own axis.

[0094] Step 5: Calculate the result according to step 4 As well as the frequency holding characteristics of the linear system, the variation law of the bow swing angle θ2 is θ2=A2sin(2ω1t)+θ 20 ; Among them, A2 is the bow swing amplitude, 2ω1 is the bow swing angular frequency, t is the movement time, θ 20 is the yaw equilibrium angle. Then the bow swing angular velocity is The angular acceleration is

[0095] like Figure 7 As shown in Figure 2, the bow swing force analysis. The differential equation of the underwater robot bow swing drive is: Among them, J2 is the bow swing moment of inertia of the swing device, C2 is the damping coefficient, and k2 is the torsional stiffness of the torsion spring.

[0096] Then we have:

[0097]

[0098] in,

[0099]

[0100] When 4J2A2ω1 2 When -k2A2=0, the torque required for the underwater robot's bow swing reaches the minimum. At this time, cosλ2=1, sinλ2=0, λ2=0, under the same torque conditions, the underwater robot's bow swing amplitude will reach the maximum value, and That is, the bow swing amplitude of the underwater robot is The yaw balance angle is

[0101] Step 6: According to 4J2A2ω1 2 -k2A2=0,that is,4J2ω1 2 -k2=0, adjust the underwater robot's bow swing inertia to

[0102] like Figure 7 As shown, it is assumed that the bow left mass block and the bow right mass block are initially located at the center of their respective strokes, and the distance from the vertical line of the swing device is r 20 At this time, the bow swing inertia of the underwater robot is J 20 After the positions of the left bow mass block and the right bow mass block are adjusted synchronously, the distance from the vertical line of the swing device is r2. At this time, the inertia of the bow swing of the underwater robot is J2 = J 20 +2m2(r2 2 -r 20 2 ).Depend on have to, That is, the distance r2 between the position of the left bow mass block and the right bow mass block and the vertical line of the swing device is adjusted to

[0103] The above description is an explanation of the present invention, not a limitation of the present invention. The scope of the present invention is defined in the claims. Any modifications may be made within the scope of protection of the present invention.

Claims

1. An underwater propeller swing motion simulation experimental device, characterized by: The experimental water pool (1) includes a water pool frame (11), a crossbeam (12) is provided on the water pool frame (11), and a swing device (2) is installed on the crossbeam (12) via fasteners; The structure of the swing device (2) is as follows: it includes a top seat (201), a top shaft (205) is installed below the top seat (201) through a bearing support, an outer shaft (206) is sleeved on the outer side of the top shaft (205), a left rotating frame (212) and a right rotating frame (213) are respectively installed at both ends of the outer shaft (206) through fasteners, and a pitch inertia adjustment module (202) is fixed at the bottom of the outer shaft (206), and the left rotating frame (212) and the right rotating frame (213) are fixed at the bottom of the outer shaft (206). An intermediate plate (3) is fixed to the bottom of the intermediate plate (3), a bearing base (214) is provided below the intermediate plate (3), a groove is provided above the bearing base (214), a pair of cross roller bearings (211) are installed in the groove, the middle and lower parts of the connecting middle shaft (219) are installed on the inner side of the cross roller bearing (211), the upper part of the connecting middle shaft (219) is fixed to the bottom surface of the intermediate plate (3), and the bearing base (214) and the connecting middle shaft (219) can rotate with each other; A bow inertia adjustment module (203) is fixedly installed below the bearing base (214), and the bow inertia adjustment module (203) and the pitch inertia adjustment module (202) are perpendicular to each other in space.

2. The underwater propeller swing motion simulation experimental device according to claim 1, characterized in that: The cross section of the top seat (201) is a "π"-shaped structure.

3. The underwater propeller swing motion simulation experimental device according to claim 1, characterized in that: A left bearing (209) and a right bearing (210) are respectively placed inside the two holes below the top seat (201). The top shaft (205) is connected to the top seat (201) through the left bearing (209) and the right bearing (210), so that the top shaft (205) and the top seat (201) can rotate with each other. The left shaft uses a retaining ring (207) to axially position the left bearing (209), and the right shaft uses a retaining ring (208) to axially position the right bearing (210).

4. The underwater propeller swing motion simulation experimental device according to claim 1, characterized in that: The cross section of the outer shaft (206) is a transverse I-shaped structure.

5. The underwater propeller swing motion simulation experimental device according to claim 1, characterized in that: The bearing base (214) is a rectangular parallelepiped structure.

6. The underwater propeller swing motion simulation experimental device according to claim 1, characterized in that: A torsion spring (204) is installed between the intermediate plate (3) and the bearing base (214).

7. The underwater propeller swing motion simulation experimental device according to claim 1, characterized in that: The pitch inertia adjustment module (202) comprises a pitch screw (40), wherein the left and right ends of the pitch screw (40) are provided with a shaft, the shaft length of the left end is longer than that of the right end, the leftmost side of the shaft at the left end is used to connect with the pitch coupling (32), and the shaft at the right end is only connected with the pitch right end cover (42); the pitch screw (40) is provided with a pitch left mass block (33) and a pitch right mass block (34) of the same structure, and further comprises a pitch The lead screw base (43) is fixed with a pitching slide rail (37) at the bottom of the pitching lead screw base (43), and the pitching left mass block (33) and the pitching right mass block (34) slide along the pitching slide rail (37); the left end of the pitch coupling (32) is connected to the motor shaft, the pitching motor (31) is fixed to the leftmost end of the pitching lead screw base (43) by a fastener, and the pitching right end cover (42) is fixed to the rightmost end of the pitching lead screw base (43) by a fastener.

8. The underwater propeller swing motion simulation experimental device according to claim 7, characterized in that: The pitch screw (40) is provided with two sections of threads with the same shape and size and opposite directions.

9. The underwater propeller swing motion simulation experimental device according to claim 1, characterized in that: The structure of the bow inertia adjustment module (203) is as follows: it includes a bow screw base (63) and a bow screw (60); a bow slide rail (57) is installed on the bottom surface of the bow screw base (63); the bow screw (60) has two sections of threads with the same shape and size and opposite directions; the bow motor (51) is fixed on the leftmost end of the bow screw base (63); and the bow right end cover (62) is fixed on the rightmost end of the bow screw base (63); the bow left The right end of the nut (55) passes through the middle part of the bow left mass block (53), and the left end of the bow right nut (56) passes through the middle part of the bow right mass block (54). The bow left nut (55) and the bow right nut (56) are respectively installed on two sections of opposite threads of the bow screw (60) and are symmetrical about the intersection of the two sections of opposite threads. The bow left mass block (53) and the bow right mass block (54) are matched with the bow slide rail (57).

10. A method for adjusting the swing amplitude of an underwater propeller swing motion simulation experimental device according to claim 1, characterized in that: The following operating procedures are included: Step 1: Set the pitch angle θ1 according to the experimental requirements, express the pitch angular velocity and pitch angular acceleration, and then obtain the differential equation of the underwater robot's pitch drive based on the pitch force analysis, and then calculate the required torque for the underwater robot's pitch. Step 2: According to J1ω1 2 -m1gl1=0, adjust the pitch and swing inertia of the underwater robot. Assume that the pitch left mass block and the pitch right mass block are initially located in the center of their respective strokes, and the distance from the vertical line of the swing device is r 10 , the pitching inertia of the underwater robot at this time is J 10 After the positions of the left and right pitching mass blocks are synchronously adjusted, the distance from the vertical line of the swing device is r1, which represents the pitching inertia J1 of the underwater robot. Find r1; Step 3: According to the mapping relationship between the underwater propeller thrust T and the underwater propeller speed ω0, the propeller speed ω0 is calculated, and the propeller is controlled to run at the speed ω0; Step 4: Calculate the gyroscopic torque M2 generated by the underwater propeller motor and blade components during rotation; Step 5: Based on the calculation result M2 in the fourth step and the frequency retention characteristics of the linear system, let the bow swing angle θ2 be expressed as the bow swing angular velocity and angular acceleration, and then perform bow swing force analysis. According to the differential equation of the underwater robot's bow swing drive, the underwater robot's bow swing amplitude A2 and yaw balance angle θ when the underwater robot's bow swing amplitude reaches its maximum value can be calculated. 20 ; Step 6: The torque required for the underwater robot's bow swing reaches the minimum value, and the underwater robot's bow swing inertia is adjusted. Assume that the bow left mass block and the bow right mass block are initially located at the center of their respective strokes, and the distance from the vertical line of the swing device is r 20 At this time, the bow swing inertia of the underwater robot is J 20 After the positions of the left bow mass block and the right bow mass block are synchronously adjusted, the distance from the perpendicular line of the swing device is r2, which can be expressed as the bow swing inertia J2 of the underwater robot, and r2 can be calculated.

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