Small soft robotic fish tail fin thrust measuring device

Abstract

The utility model relates to a small soft robotic fish tail fin thrust measuring device, which is characterized in that the upper end of a swing rod is hinged with a mounting frame and rotates around the Y direction, a tension sensor is arranged on one side of the mounting frame and is connected with the swing rod through a stay wire, and a soft driver is hinged with the lower end of the swing rod and rotates around the Z direction; a robotic fish tail fin is arranged at the rear end of the soft driver; a hinge frame is arranged at the lower end of the swing rod, a hinge seat is arranged at the front end of the soft driver, the front end of the hinge seat is rotationally connected with the hinge frame through a hinge shaft, the hinge shaft is arranged at the center of a limiting disc, limiting pin holes are evenly distributed in the circumferential edge of the limiting disc, and limiting pins for limiting the swing angle of the hinge seat are inserted into two of the limiting pin holes. The robot fish tail fin is driven by the soft driver to periodically swing around the lower end of the swing rod, thrust generated by the robot fish tail fin can drive the swing rod to rotate and pull the pull wire, and therefore thrust measurement of the robot fish tail fin can be achieved through the tension sensor connected with the pull wire.

Description

Technical Field

[0001] The utility model relates to the technical field of underwater soft robot swimming thrust measurement, in particular to a small soft robot tail fin thrust measurement device. Background Art

[0002] Underwater swimming robots play an important role in underwater tracking, hydrological monitoring, seabed inspection and other fields. Underwater swimming robots are mainly driven by the swing of the fish tail. For example, patents such as CN111572742A and CN218534616U disclose mechanical fish tail structures. However, the above structures are purely mechanical structures and their structural composition is relatively complex. There are also soft mechanical fish tail structures in the existing technology, such as those disclosed in patents such as CN116552763A and CN116464685B. As for the mechanical fish tail, the swimming characteristics of the underwater robot are closely related to the thrust generated by the periodic swing of the fish tail. Therefore, accurately measuring the thrust of the robot under different working conditions is crucial for optimizing the robot body structure design and precisely controlling the robot's swimming behavior.

[0003] However, existing technologies for measuring the thrust of underwater robots while swimming mostly fix the robot's head or body on a vertical axis, then connect the vertical axis to a six-axis force sensor and measure the thrust of the soft robot under fixed constraints. This thrust measurement method limits the fluctuations of the robot's head and front body, so it is significantly different from the actual situation when the robot swims, and its measurement accuracy needs to be further improved. Utility Model Content

[0004] The purpose of the utility model is to provide a small soft robotic fish tail fin thrust measurement device, which drives the robotic fish tail fin to swing around the lower end of the swing rod and periodically around the Z direction to simulate the robot swimming through a soft driver, and the thrust generated by the robotic fish tail fin will drive the swing rod to rotate around the Y direction and pull the pull wire, so that the thrust of the robotic fish tail fin can be measured by using a tension sensor connected to the pull wire.

[0005] The purpose of this utility model is achieved through the following technical solutions:

[0006] A small soft robot fish tail fin thrust measuring device includes a mounting frame, a swing arm, a soft driver, a pull wire and a tension sensor, wherein the upper end of the swing arm is hinged to the mounting frame and rotates around the Y direction, a vertical beam is provided at the end of the mounting frame, and a tension sensor is provided on the vertical beam, the tension sensor is connected to the swing arm through a pull wire, the soft driver is hinged to the lower end of the swing arm and rotates around the Z direction, and a robot fish tail fin is provided at the rear end of the soft driver; the lower end of the swing arm is provided with an articulated frame, the front end of the soft driver is provided with an articulated seat, and the front end of the articulated seat is rotatably connected to the articulated frame through an articulated shaft, the articulated shaft is provided at the center of a limit plate, and the circumferential edge of the limit plate is evenly distributed with limit pin holes, limit pins are inserted into any two limit pin holes, and two limit pins are provided on both sides of the articulated seat.

[0007] The articulated seat includes a connecting sleeve and an articulated disc, wherein the connecting sleeve is fixedly connected to the front end of the soft driver, the articulated disc is inserted into the articulated frame and is rotatably connected to the articulated frame through the articulated shaft, and a first bearing is provided in the articulated disc and is sleeved on the articulated shaft.

[0008] The circumferential edge of the limiting disk is evenly distributed with scale lines.

[0009] A tensioning bracket is provided on the side of the swing rod away from the tension sensor, and a wire tensioning assembly is provided on the tensioning bracket.

[0010] The wire tensioning assembly includes an inner nut, an outer ring and a stud, wherein the stud is threadedly inserted into the tensioning bracket, the inner nut is threadedly sleeved on the stud, and the outer ring is sleeved on the inner nut and connected to the wire.

[0011] A wire guide sleeve for the wire to pass through is provided on the side of the swing rod close to the tension sensor.

[0012] A hinge block is provided on the lower side of the mounting frame, and the upper end of the swing rod is rotatably connected to the hinge block through a swing hinge shaft, wherein a second bearing is provided in the hinge block and sleeved on the swing hinge shaft.

[0013] The mounting frame is L-shaped, and a fixing seat is provided at one end of a horizontal beam of the mounting frame, and the vertical beam is vertically provided at the other end.

[0014] The soft drive is cylindrical, and drive units are provided on both sides of the soft drive to wrap the internal spring. The drive unit includes multiple layers of unit dielectric films stacked from the inside to the outside, wherein unit electrodes are provided on the remaining layers of unit dielectric films except the innermost and outermost layers. Voltage is applied alternately to the drive units on both sides of the soft drive.

[0015] The advantages and positive effects of this utility model are:

[0016] 1. The utility model uses a soft driver to drive the robotic fish tail fin to swing around the lower end of the swing rod and periodically around the Z direction to simulate the robot swimming. The thrust generated by the robotic fish tail fin drives the swing rod to rotate around the Y direction and pull the pull wire, so that the thrust of the robotic fish tail fin can be measured using a tension sensor connected to the pull wire. The entire device is simple, easy to assemble and disassemble, and easy to use.

[0017] 2. The utility model is provided with a limit plate at the lower end of the swing rod, and the limit plate is provided with a limit pin for limiting the rotation angle of the hinge seat connected to the front end of the soft driver. This can not only limit the deflection of the robot fish tail fin due to the slight difference in the bending angles on both sides during the swinging process, but also realize different forms of measurement. When the two limit pins are inserted into the two limit pin holes closest to the hinge seat, they become fixed constraints. This situation is the traditional thrust measurement method. After pulling out both limit pins, the utility model can perform unconstrained thrust measurement of the robot fish tail fin.

[0018] 3. The utility model utilizes the wire tensioning assembly on the swing arm to adjust the tension of the wire to meet the measurement needs, and the wire tensioning assembly can first achieve rough adjustment of the height by screwing the stud, and then screwing the outer ring to drive the inner nut to achieve precise adjustment of the height. The rotation of the outer ring can also adjust the position of the head end of the wire, thereby ensuring that the tension of the wire meets the measurement requirements, and the wire tensioning assembly has a simple structure, low cost and is easy to install.

[0019] 4. The soft driver of the present invention is a dielectric elastomer soft driver, and the driving units on both sides of the soft driver are independently powered on and controlled and realize left-right alternating periodic bending motion through alternating voltage excitation, which can well simulate the left-right swinging of the robot fish tail fin. At the same time, the soft driver is a columnar structure, which is convenient for connecting with the hinge seat at the front end and the robot fish tail fin at the rear end, and is also convenient for achieving angle control. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a three-dimensional schematic diagram of the device of the utility model.

[0021] Figure 2 for Figure 1 The main view of the utility model,

[0022] Figure 3 for Figure 1 The structural cross-section view at A in the middle,

[0023] Figure 4 for Figure 1A partial enlarged view of the middle tension wire and tension sensor.

[0024] Figure 5 for Figure 2 A partial enlarged view of the middle limit plate, soft drive, and robotic fish tail fin.

[0025] Figure 6 for Figure 5 A three-dimensional diagram of the center limit plate.

[0026] Figure 7 for Figure 2 The schematic diagram of the force arm relationship of the device of the utility model is shown in FIG.

[0027] Figure 8 for Figure 1 The structural diagram of the software driver.

[0028] Figure 9 for Figure 8 The drive unit decomposition diagram in

[0029] Figure 10 for Figure 9 Schematic diagram of the design principle of the mid-drive unit Figure 1 ,

[0030] Figure 11 for Figure 9 Schematic diagram of the design principle of the mid-drive unit Figure 2 ,

[0031] Figure 12 for Figure 8 Schematic diagram of the driving unit's action status after power is supplied.

[0032] Figure 13 for Figure 1 Schematic diagram of the thrust measurement results of the robotic fish tail fin under unconstrained conditions.

[0033] Among them, 1 is a mounting frame, 101 is a fixing seat, 102 is a vertical beam, 103 is a hinge block, 2 is a cable, 201 is a cable tensioning assembly, 2011 is an inner nut, 2012 is an outer ring, 3 is a tension sensor, 4 is a hinge seat, 401 is a connecting sleeve, 402 is a hinge plate, 4021 is a first bearing, 5 is a soft drive, 501 is a drive unit, 5011 is a unit dielectric film, 5012 is a unit electrode, 502 is Spring, 503 is the end cover, 504 is the sleeve, 6 is the machine fish tail fin, 7 is the limit plate, 701 is the limit pin, 702 is the hinge shaft, 703 is the limit pin hole, 704 is the scale line, 8 is the swing rod, 801 is the swing hinge shaft, 8011 is the second bearing, 802 is the tensioning bracket, 803 is the hinge frame, 804 is the wire guide sleeve, 9 is the stud, 901 is the nut, 10 is the electrode material, 11 is the dielectric film, and 12 is the electric field. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings.

[0035] like Figures 1 to 13 As shown, the present invention includes a mounting frame 1, a swing arm 8, a soft actuator 5, a pull wire 2, and a tension sensor 3. The upper end of the swing arm 8 is hinged to the mounting frame 1 and rotates about the Y direction. The end of the mounting frame 1 is provided with a vertical beam 102, and the vertical beam 102 is provided with a tension sensor 3. The tension sensor 3 is connected to the swing arm 8 via a pull wire 2. The soft actuator 5 is hinged to the lower end of the swing arm 8 and rotates about the Z direction. The rear end of the soft actuator 5 is provided with a robotic fish tail fin 6. When the present invention is in operation, the pull wire 2 is in a tensioned state, and the soft actuator 5 drives the robotic fish tail fin 6 to periodically swing left and right about the Z direction, generating thrust. Under the action of this thrust, the swing arm 8 tends to rotate about the Y direction, thereby pulling the pull wire 2 connected to the tension sensor 3 to achieve thrust measurement.

[0036] like Figures 1-2 and Figures 5-6 As shown, in this embodiment, the lower end of the swing rod 8 is provided with an articulated frame 803, the front end of the soft driver 5 is provided with an articulated seat 4, and the front end of the articulated seat 4 is rotatably connected to the articulated frame 803 through an articulated shaft 702, and the articulated shaft 702 is provided at the center of a limit plate 7, and as shown Figure 6 As shown, the circumferential edge of the limit plate 7 is evenly distributed with limit pin holes 703 , and any two limit pin holes 703 are inserted with limit pins 701 , and the two limit pins 701 are respectively arranged on both sides of the hinge seat 4 . The limit pin 701 is used to limit the rotation angle of the articulated seat 4, and further limit the swing angle of the soft drive 5 and the robot fish tail fin 6. This can limit the excessive deflection of the robot fish tail fin 6 due to the slight difference in the bending angles on both sides during the swinging process, thereby ensuring that the tension sensor 3 measures the thrust in the forward direction. In addition, when the two limit pins 701 are inserted into the two limit pin holes 703 closest to the articulated seat 4, they become fixed constraints. In this case, measuring the swing thrust of the robot fish tail fin 6 is a traditional thrust measurement method. After pulling out both limit pins 701, the utility model can perform unconstrained thrust measurement of the robot fish tail fin 6. Therefore, the utility model can realize a variety of measurement methods through the above-mentioned limit plate 7 and limit pin 701 structure, which improves the flexibility and scope of application of the utility model. In addition, Figure 6 As shown, in this embodiment, the circumferential edge of the limit plate 7 is evenly distributed with scale lines 704 to assist in measuring the swing angle of the front end of the soft driver 5 .

[0037] like Figure 6As shown, in this embodiment, the articulated seat 4 includes a connecting sleeve 401 and a hinge disk 402, wherein the connecting sleeve 401 is fixedly connected to the front end of the soft drive 5, the hinge disk 402 is inserted into the articulated frame 803 and is rotatably connected to the articulated frame 803 through the articulated shaft 702, and a first bearing 4021 is provided in the articulated disk 402 and is sleeved on the articulated shaft 702 to realize the relative rotation of the articulated disk 402 and the articulated frame 803, and the limit pins 701 are arranged on both sides of the connecting sleeve 401 and limit the swing angle of the connecting sleeve 401.

[0038] like Figures 1-2 and Figure 4 As shown, in this embodiment, a tensioning bracket 802 is provided on the side of the swing rod 8 away from the tension sensor 3, and a wire tensioning assembly 201 is provided on the tensioning bracket 802. After the wire 2 passes through the swing rod 8, it is connected to the wire tensioning assembly 201 and tensioning is achieved.

[0039] like Figure 4 As shown, in this embodiment, the wire tensioning assembly 201 includes an inner nut 2011, an outer ring 2012 and a stud 9, wherein the stud 9 is threadedly inserted into the tensioning bracket 802, the inner nut 2011 is threadedly mounted on the stud 9, and the outer ring 2012 is mounted on the inner nut 2011 and connected to the wire 2. When the present invention is used, the nut 901 at the upper end of the stud 9 can be screwed to drive the stud 9 to move relative to the tensioning bracket 802 to achieve height adjustment of the stud 9, which also achieves rough adjustment of the height of the inner nut 2011 and the outer ring 2012, and then the outer ring 2012 is screwed to drive the inner nut 2011 to rotate and move along the stud 9 to achieve precise fine-tuning of the height. The rotation of the outer ring 2012 can also fine-tune the position of the head end of the pull wire 2, thereby achieving tension adjustment of the pull wire 2 and ensuring that the tension of the pull wire 2 meets the measurement requirements. The pull wire tensioning assembly 201 of the present invention has a simple structure, low cost and is easy to install.

[0040] like Figure 4 As shown, in this embodiment, the side of the swing arm 8 near the tension sensor 3 is provided with a wire guide sleeve 804 for the wire 2 to pass through. The wire guide sleeve 804 is used to ensure the horizontality of the wire 2. In addition, the tension sensor 3 is a well-known technology in the art and is a commercially available product. In this embodiment, the LSB200 model high-precision tension sensor is used.

[0041] like Figures 1 to 3 As shown, in this embodiment, a hinge block 103 is provided on the lower side of the mounting frame 1, and the upper end of the swing rod 8 is rotatably connected to the hinge block 103 through a swing hinge shaft 801, wherein Figure 3As shown, a second bearing 8011 is provided in the hinge block 103 and sleeved on the swing hinge shaft 801 to achieve relative rotation between the swing rod 8 and the hinge block 103 .

[0042] like Figure 1 As shown, in this embodiment, the mounting frame 1 is L-shaped, with a fixing seat 101 provided at one end of the horizontal beam to be fixed on the corresponding equipment or structure, and a vertical beam 102 provided perpendicularly at the other end of the horizontal beam.

[0043] In this embodiment, the soft driver 5 is a dielectric elastomer soft driver, such as Figures 10-11 As shown, the conventional structure of the dielectric elastomer soft actuator is a sheet structure, which includes electrode materials 10 on the upper and lower sides and a dielectric film 11 disposed between the two layers of electrode materials 10. Figure 11 As shown, when the electrode material 10 is energized, an electric field 12 is formed and the dielectric film 11 is driven to expand in the surrounding area. The above are all well-known technologies in the art.

[0044] And as Figures 8-9 As shown, the overall design of the soft drive 5 of the present invention is a columnar structure, with drive units 501 on both sides to wrap the internal spring 502. The drive unit 501 includes multiple layers of unit dielectric films 5011 stacked from the inside to the outside, wherein, except for the innermost and outermost unit dielectric films 5011, the remaining layers of the unit dielectric films 5011 are each provided with a unit electrode 5012, as shown in FIG. Figure 12 As shown, when the unit electrodes 5012 within the drive units 501 on either side are energized, they stretch the unit dielectric film 5011, thereby bending the soft actuator 5 to one side. By independently energizing and controlling the drive units 501 on both sides of the soft actuator 5 and alternating voltage excitation, the soft actuator 5 can achieve alternating left-right periodic bending motion, thereby achieving the left-right swinging of the robotic fish tail fin 6. In this embodiment, the material of the unit dielectric film 5011 can be acrylic film VHB4910 produced by 3M, and the material of the unit electrodes 5012 can be carbon black grease 864-80G.

[0045] like Figures 8-9 As shown, in this embodiment, both ends of the soft drive 5 are provided with end caps 503 and sleeves 504, wherein the end caps 503 define the positions of both ends of the spring 502, and the corresponding ends of the end caps 503 and the drive unit 501 are both provided in the sleeves 504 on the corresponding sides to achieve fixation, and the sleeves 504 can also be connected with the Figure 6 The connecting sleeve 401 on the articulated seat 6 is connected, or connected to the robot fish tail fin 6.

[0046] In this embodiment, the robotic fish tail fin 6 is manufactured using a 3D printer and is made of VeroCyan resin.

[0047] The working principle of this utility model is:

[0048] When the present invention is used, the device can be put into the pool after being assembled, wherein the fixing seat 101 at the head end of the mounting frame 1 can be fixed on the pool wall, and before the present invention device is put in, the pull wire 2 needs to be adjusted and kept taut by the pull wire tensioning assembly 201. When the device is installed in the pool, Figure 1 As shown, after the software driver 5 is powered on and started, it will swing left and right in the Z direction, thereby driving the robot fish tail fin 6 to swing left and right periodically and generate thrust. Under the action of this thrust, the swing rod 8 will rotate around the swing hinge 801, that is, it will produce a tendency to rotate around the Y direction, so it will pull the pull wire 2 connected to the tension sensor 3 to achieve thrust measurement.

[0049] In an application example of the present invention, the driving voltage of the driving units 501 on both sides of the soft driver 5 is 5kV, the driving frequency is 1Hz, and the two limit pins 701 inserted on the limit plate 7 make the swing angle of the front end of the soft driver 5 maximum 30° to prevent the center of the robot fish tail fin 6 from deviating from the X axis during the swing process. Figure 7 As shown, the distance between the center axis of the robot fish tail fin 6 and the center axis of the swing hinge shaft 801 is L0+L1=3L0, and the distance between the center axis of the tension sensor 3 and the center axis of the swing hinge shaft 801 is L0. Therefore, the thrust of the robot fish tail fin 6 should be 1 / 3 of the tension measured by the tension sensor 3.

[0050] In another application example of the present invention, the two limit pins 701 are completely pulled out, so that the front end of the soft driver 5 is completely unconstrained, and the thrust measurement results of the robot fish tail fin 6 under no constraints are as follows: Figure 13 shown.

Claims

1. A small soft robotic fish tail fin thrust measurement device, characterized by: The invention comprises a mounting frame (1), a swinging rod (8), a soft driver (5), a pull wire (2) and a tension sensor (3), wherein the upper end of the swinging rod (8) is hinged to the mounting frame (1) and rotates around the Y direction, a vertical beam (102) is provided at the end of the mounting frame (1), and the tension sensor (3) is provided on the vertical beam (102), the tension sensor (3) is connected to the swinging rod (8) through the pull wire (2), the soft driver (5) is hinged to the lower end of the swinging rod (8) and rotates around the Z direction, and a mechanical fish tail fin (6) is provided at the rear end of the soft driver (5); The lower end of the swing rod (8) is provided with an articulated frame (803), the front end of the soft driver (5) is provided with an articulated seat (4), and the front end of the articulated seat (4) is rotatably connected to the articulated frame (803) through a hinge shaft (702), the hinge shaft (702) is provided at the center of a limit plate (7), and the circumferential edge of the limit plate (7) is evenly distributed with limit pin holes (703), and any two limit pin holes (703) are inserted into the limit pin holes (701), and the two limit pins (701) are respectively provided on both sides of the articulated seat (4).

2. The small-scale soft robotic fish tail fin thrust measurement device according to claim 1, characterized in that: The hinge seat (4) comprises a connecting sleeve (401) and a hinge disc (402), wherein the connecting sleeve (401) is fixedly connected to the front end of the soft driver (5), the hinge disc (402) is inserted into the hinge frame (803) and is rotatably connected to the hinge frame (803) via the hinge shaft (702), and a first bearing (4021) is provided in the hinge disc (402) and is sleeved on the hinge shaft (702).

3. The small-scale soft robotic fish tail fin thrust measurement device according to claim 1, characterized in that: The circumferential edge of the limiting plate (7) is evenly distributed with scale lines (704).

4. The small-scale soft robotic fish tail fin thrust measurement device according to claim 1, characterized in that: A tensioning bracket (802) is provided on the swing rod (8) at a side away from the tension sensor (3), and a tensioning wire tensioning assembly (201) is provided on the tensioning bracket (802).

5. The small-scale soft robotic fish tail fin thrust measurement device according to claim 4, characterized in that: The wire tensioning assembly (201) includes an inner nut (2011), an outer ring (2012) and a stud (9), wherein the stud (9) is threadedly inserted into the tensioning bracket (802), the inner nut (2011) is threadedly mounted on the stud (9), and the outer ring (2012) is mounted on the inner nut (2011) and connected to the wire (2).

6. The small-scale soft robotic fish tail fin thrust measurement device according to claim 1, characterized in that: A wire guide sleeve (804) for the wire (2) to pass through is provided on the side of the swing rod (8) close to the tension sensor (3).

7. The small-scale soft robotic fish tail fin thrust measurement device according to claim 1, characterized in that: A hinge block (103) is provided on the lower side of the mounting frame (1), and the upper end of the swing rod (8) is rotatably connected to the hinge block (103) via a swing hinge shaft (801), wherein a second bearing (8011) is provided in the hinge block (103) and sleeved on the swing hinge shaft (801).

8. The small-scale soft robotic fish tail fin thrust measurement device according to claim 1, characterized in that: The mounting frame (1) is L-shaped, and a fixing seat (101) is provided at one end of a horizontal beam of the mounting frame (1), and the vertical beam (102) is vertically provided at the other end.

9. The small-scale soft robotic fish tail fin thrust measurement device according to claim 1, characterized in that: The soft driver (5) is columnar, and drive units (501) are provided on both sides of the soft driver (5) to wrap the internal spring (502), and the drive units (501) include multiple layers of unit dielectric films (5011) stacked from the inside to the outside, wherein unit electrodes (5012) are provided on each layer of the unit dielectric films (5011) except the innermost and outermost layers, and voltages are applied alternately to the drive units (501) on both sides of the soft driver (5).

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