Adjustable constant-force clamping jaw based on torsion quasi-zero stiffness

Abstract

The adjustable constant-force clamping jaw comprises a torsion input shaft, a torsion output shaft, a constant-force output mechanism and a force adjusting mechanism, the torsion input shaft is in transmission connection with the output end of a first motor, and the torsion output shaft is rotationally connected to the end, away from the torsion output shaft, of an outer frame; the torsion input shaft and the torsion output shaft rotate coaxially, the two ends of the constant force output mechanism are connected with the torsion input shaft and the torsion output shaft correspondingly, the constant force output mechanism is used for flexibly connecting the torsion input shaft and the torsion output shaft and outputting constant torsion to the torsion output shaft, and the force adjusting mechanism is connected with the torsion input shaft. And the force adjusting mechanism is rotationally connected with the torsion output shaft, and the force adjusting mechanism is used for adjusting the torsion output to the torsion input shaft by the constant force output mechanism, and through the technical scheme, the problem that in the prior art, a constant force clamping jaw is difficult to clamp through set clamping force is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of motor clamps, and in particular to an adjustable constant-force clamp based on torsional quasi-zero stiffness. Background Art

[0002] In industrial production, clamping mechanisms can simulate the grasping and releasing actions of human hands, and are widely used in machine tool clamping, robot end effectors, and precision machining. However, since the clamping mechanism cannot accurately control the clamping force, it may cause certain damage to the clamped object. Based on this, research on constant-force grippers has been conducted to clamp objects by outputting constant pressure.

[0003] Traditional constant force grippers are mostly controlled by hydraulic, air source or other pressure or voice coil motors. Constant force grippers driven by hydraulic, air source or other pressure often have the disadvantage of difficulty in regulating the clamping force, while constant force grippers that use a voice coil motor to drive the grippers for clamping use a pressure sensor to provide feedback on the clamping force, which has a feedback lag and can easily cause damage to the clamped object. It can be seen that the current constant force grippers still have some shortcomings, namely, it is difficult to accurately output the set clamping force to the object when clamping the object, which makes the overall robustness of the system low. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In view of the deficiencies of the prior art, the present invention provides an adjustable constant force clamp based on torsional quasi-zero stiffness to solve the problem in the prior art that the constant force clamp is difficult to clamp with a set clamping force as mentioned in the background art.

[0006] (2) Technical solution

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] Preferably, an adjustable constant force clamp based on torsional quasi-zero stiffness comprises an external frame, a motor 1 and a clamping mechanism, wherein the motor 1 is fixedly mounted on the external frame, the clamping mechanism is arranged on an end of the external frame away from the motor 1, and further comprises a torque input shaft, a torque output shaft, a constant force output mechanism and a force adjustment mechanism, the torque input shaft is rotatably connected to the external frame, the torque input shaft is transmission-connected to the output end of the motor 1, the torque output shaft is rotatably connected to an end of the external frame away from the torque output shaft, and the torque output The shaft is connected to the clamping mechanism, the torque input shaft and the torque output shaft rotate coaxially, the two ends of the constant force output mechanism are respectively connected to the torque input shaft and the torque output shaft, the constant force output mechanism is used to flexibly connect the torque input shaft and the torque output shaft, and output a constant torque to the torque output shaft, the force adjustment mechanism is connected to the torque input shaft, the force adjustment mechanism is rotatably connected to the torque output shaft, and the force adjustment mechanism is used to adjust the torque output by the constant force output mechanism to the torque input shaft.

[0009] Furthermore, the constant force output mechanism includes an outer ring magnetic frame, an inner ring magnetic frame and a support sleeve, the outer ring magnetic frame is fixedly connected to the torque input shaft, the outer ring magnetic frame is arranged in a circular shape, a plurality of outer ring magnets are arranged on the outer ring magnetic frame, the inner ring magnetic frame is fixedly connected to the torque output shaft, the inner ring magnetic frame is arranged in a ring shape, the inner ring magnetic frame extends into the outer ring magnetic frame, a plurality of inner ring magnets are arranged on the inner ring magnetic frame, the support sleeve is fixedly connected to the center of the outer ring magnetic frame, the support sleeve passes through the inner ring magnetic frame, and the support sleeve is rotatably connected to the torque output shaft.

[0010] Furthermore, a gap is left between the inner ring magnet and the outer ring magnet, the inner ring magnet and the outer ring magnet are both arranged in a fan shape, the inner ring magnet and the outer ring magnet correspond to each other, and multiple inner ring magnets and multiple outer ring magnets are respectively arranged in a circle on the inner ring magnetic frame and the outer ring magnetic frame.

[0011] As a further solution of the present application, the force adjustment mechanism includes a positive stiffness spring, a lower support plate and a torsion assembly. The positive stiffness spring is fixedly connected to the torque input shaft, the positive stiffness spring is sleeved on the outer ring magnetic frame, the lower support plate is rotatably connected to one end of the inner ring magnetic frame close to the torque output shaft, the end of the positive stiffness spring away from the torque input shaft is fixedly connected to the lower support plate, and the torsion assembly is arranged on the side of the lower support plate away from the positive stiffness spring, and the torsion assembly is used to drive the positive stiffness spring to twist.

[0012] As a further solution of the present application, the torsion assembly includes a worm gear, motor 2 and a worm, the worm gear is fixedly mounted on the torque output shaft, multiple motors 2 are provided, and multiple motors 2 are fixedly mounted on the lower support plate, and multiple motors 2 are arranged in a circle, multiple worms are provided, and multiple worms are rotatably connected to the lower support plate, each worm is transmission-connected to the output end of one motor 2, and multiple worms are engaged with the worm gear.

[0013] As a preferred technical solution of the present application, when the output end of the second motor drives the worm to rotate, the lower support plate and the inner ring magnetic frame can rotate relative to each other, the output end of the second motor can rotate forward and reverse, and the lower support plate can rotate clockwise and counterclockwise.

[0014] It should also be noted that, after the clamping mechanism clamps the object, the inner ring magnetic frame and the lower supporting plate stop rotating, and the outer ring magnetic frame can rotate relative to the inner ring magnetic frame.

[0015] (3) Beneficial effects

[0016] Compared with the prior art, the present invention provides an adjustable constant force clamp based on torsional quasi-zero stiffness, which has the following beneficial effects:

[0017] In the present invention, by setting a constant force output mechanism, flexible clamping force output can be performed, avoiding damage caused by the rigid connection of the clamping jaws when a large clamping force is applied to the object. By setting a force adjustment mechanism, in cooperation with the constant force output mechanism, a range of stable output clamping force is achieved, which facilitates the determination of the constant force size, and thus allows for accurate clamping force determination, avoiding a large deviation between the output clamping force and the set clamping force. Therefore, compared with the existing constant force clamping jaws, the adjustable constant force clamping jaw based on torsional quasi-zero stiffness can perform simple clamping force adjustment, and at the same time, the adjustment range is larger, and the clamping force can be finely adjusted, which is suitable for clamping in a variety of scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the overall structure of a preferred embodiment of the present application;

[0019] Figure 2 This is a schematic cross-sectional view of a torque input shaft in a preferred embodiment of the present application;

[0020] Figure 3 This is a schematic cross-sectional view of the torque input shaft, the positive stiffness spring, and the lower support plate in a preferred embodiment of the present application;

[0021] Figure 4 This is a schematic cross-sectional view of a positive stiffness spring, an inner magnetic frame, and an outer magnetic frame in a preferred embodiment of the present application;

[0022] Figure 5 This is a schematic cross-sectional view of the inner and outer magnetic rings in a preferred embodiment of the present application;

[0023] Figure 6 This is a schematic diagram of the overall structure from another perspective of a preferred embodiment of the present application;

[0024] Figure 7 A schematic diagram of the polarization direction of a magnet in a preferred embodiment of the present application;

[0025] Figure 8 Schematic diagram of a force-displacement curve of a positive stiffness spring when the initial torsion angle is zero in a preferred embodiment of the present application;

[0026] Figure 9 This is a schematic diagram of a force-displacement curve when the initial torsion angle of the positive stiffness spring is 10 degrees in a preferred embodiment of the present application.

[0027] In the figure: 1. External frame; 2. Motor 1; 3. Torque input shaft; 4. Torque output shaft; 5. Outer ring magnetic frame; 6. Outer ring magnet; 7. Inner ring magnetic frame; 8. Inner ring magnet; 9. Support sleeve; 10. Positive stiffness spring; 11. Lower support plate; 12. Worm gear; 13. Motor 2; 14. Worm; 15. Slide rail; 16. Gear; 17. Rack; 18. Clamp. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] See also Figures 1 to 9Preferably, an adjustable constant force clamp based on torsional quasi-zero stiffness includes an external frame 1, a motor 2 and a clamping mechanism, wherein the motor 2 is fixedly mounted on the external frame 1, and the clamping mechanism is arranged on an end of the external frame 1 away from the motor 2, and further includes a torque input shaft 3, a torque output shaft 4, a constant force output mechanism and a force adjustment mechanism, the torque input shaft 3 is rotatably connected to the external frame 1, the torque input shaft 3 is transmission-connected to the output end of the motor 2, the torque output shaft 4 is rotatably connected to the end of the external frame 1 away from the torque output shaft 4, the torque output shaft 4 is connected to the clamping mechanism, the torque input shaft 3 and the torque output shaft 4 rotate coaxially, and the two ends of the constant force output mechanism are respectively connected to the torque input shaft 3 and the torque output The torque input shaft 3 and the torque output shaft 4 are connected, the constant force output mechanism is used to flexibly connect the torque input shaft 3 and the torque output shaft 4, and output a constant torque to the torque output shaft 4, the force adjustment mechanism is connected to the torque input shaft 3, the force adjustment mechanism is rotatably connected to the torque output shaft 4, the force adjustment mechanism is used to adjust the torque output to the torque input shaft 3 by the constant force output mechanism, the constant force output mechanism flexibly connects the torque input shaft 3 and the torque output shaft 4, the force adjustment mechanism also flexibly connects the torque input shaft 3 and the torque output shaft 4, when clamping an object, the force adjustment mechanism can increase or decrease the torque output by the constant force output mechanism to the torque output shaft 4, thereby adjusting the clamping force of the clamping jaw 18.

[0030] See also Figures 1 to 5 Furthermore, the constant force output mechanism includes an outer ring magnetic frame 5, an inner ring magnetic frame 7 and a support sleeve 9. The outer ring magnetic frame 5 is fixedly connected to the torque input shaft 3. The outer ring magnetic frame 5 is set to a circle. A plurality of outer ring magnets 6 are arranged on the outer ring magnetic frame 5. The inner ring magnetic frame 7 is fixedly connected to the torque output shaft 4. The inner ring magnetic frame 7 is set to a ring. The inner ring magnetic frame 7 extends into the outer ring magnetic frame 5. A plurality of inner ring magnets 8 are arranged on the inner ring magnetic frame 7. The support sleeve 9 is fixedly connected to the center of the outer ring magnetic frame 5. The support sleeve 9 passes through the inner ring magnetic frame 7. The support sleeve 9 is rotatably connected to the torque output shaft 4. The output end of the motor 2 drives the torque input shaft 3 to rotate, and the torque input shaft 3 drives the outer ring magnetic frame 5 to rotate. The outer ring magnetic frame 5 drives the inner ring magnetic frame 7 to rotate through the magnetic attraction and repulsion between the inner ring magnet 8 and the outer ring magnet 6, and the outer ring magnetic frame 5 and the inner ring magnetic frame 7 are kept coaxial and non-contact in rotation through the support sleeve 9.

[0031] See also Figures 3 to 7Furthermore, a gap is left between the inner ring magnet 8 and the outer ring magnet 6. The inner ring magnet 8 and the outer ring magnet 6 are both arranged in a fan shape. The inner ring magnet 8 corresponds to the outer ring magnet 6. Multiple inner ring magnets 8 and multiple outer ring magnets 6 are respectively arranged in a circular manner on the inner ring magnetic frame 7 and the outer ring magnetic frame 5. In this embodiment, there are eight inner ring magnets 8 and sixteen outer ring magnets 6, all of which are arranged at equal intervals in the circle. Each inner ring magnet 8 corresponds to two outer ring magnets 6, and the two outer ring magnets 6 form a group. The polarization directions of the inner ring magnets 8 and the outer ring magnets 6 are divided into two directions facing the circle. The polarization directions of adjacent inner ring magnets 8 are opposite, and the polarization directions of adjacent groups of outer ring magnets 6 are opposite. The inner ring magnets 8 with their polarization directions facing the center of the circle correspond to the outer ring magnets 6 with their polarization directions away from the center of the circle, so that each inner ring magnet 8 and each corresponding group of outer ring magnets 6 maintain an attractive state, and there is a repulsive force between the phase-shifted magnets, forming a magnetic spring between the inner ring magnetic frame 7 and the outer ring magnetic frame 5. When the outer ring magnetic frame 5 rotates, the outer ring magnets 6 pull the corresponding inner ring magnets 8 through the magnetic attraction, and through the magnetic repulsion. The force pushes the inner ring magnet 8 on the side of the corresponding inner ring magnet 8, which in turn causes the inner ring magnetic frame 7 to rotate when the outer ring magnetic frame 5 rotates, and because there is no rigid connection between the inner ring magnetic frame 7 and the outer ring magnetic frame 5, the supporting sleeve 9 only maintains the axial distance between the inner ring magnetic frame 7 and the outer ring magnetic frame 5, and the rotation of the inner ring magnetic frame 7 is subject to the flexible connection of the outer ring magnetic frame 5. It can be seen from the above explanation of the principle of the flexible connection between the inner ring magnetic frame 7 and the outer ring magnetic frame 5 that at the same time, when the inner ring magnet 8 cannot rotate due to external force, the outer ring magnet 6 still keeps rotating, and the inner ring magnetic frame 7 It will gradually rotate relative to the outer ring magnetic frame 5. Through experiments, we found that as the relative torsion angle between the inner ring magnetic frame 7 and the outer ring magnetic frame 5 gradually increases, the torque generated by the outer ring magnetic frame 5 increases linearly. When the torsion angle is too large, the torque decreases linearly and then returns to the torque when the torsion angle is 0 degrees. At this time, there is a misalignment between the inner ring magnet 8 and the outer ring magnet 6. Since the torque output by the magnetic spring is fluctuating, it is difficult to accurately judge when the torque provided is the required torque. Therefore, a stable and settable torque range is required to facilitate stable constant force output.

[0032] See also Figures 3 to 7As the torsion angle increases, the torque generated by the inner ring magnetic frame 7 and the outer ring magnetic frame 5 increases periodically, then decreases and then increases again, while the torque output by the positive stiffness spring 10 after torsion is linear. After the positive stiffness spring 10 is twisted clockwise, the positive stiffness spring 10 outputs a counterclockwise torque. After the positive stiffness spring 10 is twisted in the rotation direction of the outer ring magnetic frame 5, the positive stiffness spring 10 outputs a torque in the opposite direction of the rotation of the outer ring magnetic frame 5. After the positive stiffness spring 10 is twisted in the opposite direction of the rotation of the outer ring magnetic frame 5, the positive stiffness spring 10 outputs a torque in the rotation direction of the outer ring magnetic frame 5, and then applies a torque in the opposite and same directions as the rotation direction of the torque output shaft 4 to the lower support plate 11 to reduce and increase the torque output by the torque output shaft 4 to the gear 16, thereby adjusting the torque.

[0033] See also Figures 1 to 6 As a further solution of the present application, the force adjustment mechanism includes a positive stiffness spring 10, a lower support plate 11 and a torsion assembly. The positive stiffness spring 10 is fixedly connected to the torque input shaft 3, the positive stiffness spring 10 is sleeved on the outer ring magnetic frame 5, and the lower support plate 11 is rotatably connected to one end of the inner ring magnetic frame 7 close to the torque output shaft 4. The end of the positive stiffness spring 10 away from the torque input shaft 3 is fixedly connected to the lower support plate 11, and the torsion assembly is arranged on the side of the lower support plate 11 away from the positive stiffness spring 10. The torsion assembly is used to drive the positive stiffness spring 10 to twist. The torsion assembly can drive the lower part of the positive stiffness spring 10 to twist. When the torque input shaft 3 does not rotate, the torsion of the lower part of the positive stiffness spring 10 will increase the elastic potential energy inside the spring. When the rotation stops, the positive stiffness spring 10 will release the torsion in the opposite direction of rotation, pushing the lower support plate 11 and the torque input shaft 3 to rotate relative to each other in the opposite direction to when the positive stiffness spring 10 is twisted.

[0034] See also Figures 1 to 4As a further solution of the present application, the torsion assembly includes a worm gear 12, a motor 2 13 and a worm 14. The worm gear 12 is fixedly mounted on the torque output shaft 4. There are multiple motors 2 13, and multiple motors 2 13 are fixedly mounted on the lower support plate 11. Multiple motors 2 13 are arranged in a circle. There are multiple worm gears 14, and multiple worm gears 14 are rotatably connected to the lower support plate 11. Each worm gear 14 is transmission-connected to the output end of a motor 2 13, and multiple worm gears 14 are meshed with the worm gear 12. In this embodiment, there are two motors 2 13 and two worm gears 14. When the output end of the motor 2 13 drives the worm gear 14 to rotate, the worm gear 14 drives the worm gear 1 2 rotates, causing the torque output shaft 4 and the lower supporting plate 11 to rotate relative to each other. At this time, due to the magnetism between the inner ring magnetic frame 7 and the outer ring magnetic frame 5, a magnetic spring is formed. When the worm gear 12 and the inner ring magnetic frame 7 are twisted, the magnetic spring and the positive stiffness spring 10 are twisted in opposite directions, causing the inner ring magnetic frame 7 and the lower supporting plate 11 to twist in opposite directions at the same time. The twisting angles are not necessarily the same, but the torques are the same. At this time, by twisting the lower supporting plate 11 by a certain angle in advance, the torque output shaft 4 is subjected to a torque in the rotation direction or the opposite direction by the positive stiffness spring 10 during clamping, thereby adjusting the torque output by the constant force output mechanism to achieve the effect of adjusting the clamping force.

[0035] See also Figures 1 to 6 As the preferred technical solution of the present application, when the output end of motor 2 13 drives the worm 14 to rotate, the lower support plate 11 and the inner ring magnetic frame 7 can rotate relative to each other. The output end of motor 2 13 can rotate forward and flip, and the lower support plate 11 can rotate clockwise and counterclockwise. Looking from bottom to top, when the gear 16 rotates clockwise, the two clamping claws 18 slide toward each other to clamp the object, and the output shaft of motor 1 2 drives the torque input shaft 3, the outer ring magnetic frame 5, the inner ring magnetic frame 7, the lower tray and the torque output shaft 4 to rotate clockwise.

[0036] It should also be noted that, after the clamping mechanism clamps the object, the inner ring magnetic frame 7 and the lower supporting plate 11 stop rotating, and the outer ring magnetic frame 5 can rotate relative to the inner ring magnetic frame 7 .

[0037] See also Figure 6The clamping mechanism includes a slide rail 15, a gear 16, a rack 17 and a clamping jaw 18. There are two slide rails 15, which are fixedly connected to the external frame 1. The gear 16 is fixedly connected to the torque output shaft 4. The gear 16 is arranged directly on the two slide rails 15. There are two racks 17, which are slidably arranged on the two slide rails 15 respectively. The two racks 17 are respectively engaged with the gear 16 on both sides of the gear 16. The two clamping jaws 18 are respectively fixedly connected to the two racks 17. When the gear 16 rotates, it can drive the two clamping jaws 18 to move in the opposite direction. When the torque output shaft 4 drives the gear 16 to rotate so that the two clamping jaws 18 clamp the object, the two clamping jaws 18 stop moving. At this time, the constant force output mechanism and the force adjustment mechanism gradually increase the torque on the torque output shaft 4 to the set torque, thereby completing the constant force clamping of the object.

[0038] In this embodiment, the output current of motor 2 can be detected. When the current output by motor 2 is stable, the two clamping jaws 18 move at a constant speed. When the object is clamped, the two clamping jaws 18 stop sliding. At this time, the torque applied to the torque output shaft 4 by the constant force output mechanism and the force adjustment mechanism gradually increases, and the output current of motor 2 also gradually increases until the clamping jaw 18 reaches the set clamping force. At this time, the output current of motor 2 is stable and unchanged. At this time, the torque output shaft 4 can be locked, thereby fixing the clamping force of the clamping jaw 18, and clamping the object by constant force.

[0039] See also Figures 8 and 9, adjust the clamping force before clamping the object. When the torsion component drives the lower support plate 11 to rotate clockwise, the positive stiffness spring 10 applies a counterclockwise torque to the lower support plate 11. When the torsion component drives the lower support plate 11 to rotate counterclockwise, the positive stiffness spring 10 applies a clockwise torque to the lower support plate 11. Through experiments, it is found that the linear graph of the torque change of the magnetic spring and the positive stiffness spring 10 as the torsion angle changes. By customizing the parameters such as the material and diameter of the positive stiffness spring 10, the positive stiffness spring 10 can be made into a 0, is the same as the speed at which the torque decreases when the magnetic spring torsion angle is between 30 and 60 degrees. At this time, the torque of the magnetic spring and the positive stiffness spring 10 is added to form a constant torque. The torque size when the positive stiffness spring 10 is not twisted through the torsion component and reaches the constant force torque is used as the reference torque. When the torque input shaft 3 rotates, the torque output shaft 4 is driven to rotate by the two flexible connections of the magnetic spring and the positive stiffness spring 10. The clamping force is set by the torque transmitted to the torque output shaft 4. When the torque required for the clamping force is greater than the reference torque, the torsion assembly drives the lower support plate 11 to rotate counterclockwise. After the rotation stops, the positive stiffness spring 10 provides a clockwise torque to the torque output shaft 4 through the self-locking effect of the worm 14 and the worm wheel 12. When the motor drives the torque input shaft 3 to rotate, the clamping claw 18 clamps the object, and the torque output shaft 4 stops rotating. The torque input shaft 3 drives the outer ring magnetic frame 5 and the upper part of the positive stiffness spring 10 to rotate at the same time. When the torsion angle of the positive stiffness spring 10, and the inner ring magnetic frame 7 and the outer When the torsion angles between the coil magnetic frames 5 reach between 30 and 60 degrees, the torque output by the torque output shaft 4 is constant. At this time, the motor 2 detects that the output current is constant, locks the torque input shaft 3, and outputs a constant torque. When the torque required by the preset clamping force is less than the reference torque, the lower support plate 11 can be rotated clockwise, and the positive stiffness spring 10 will apply a counterclockwise torque to the torque output shaft 4. When the torsion angle reaches the constant torque output range of 30 to 60 degrees, the output torque is reduced.

[0040] Figure 8 and Figure 9 The magnetic spring in the clamping is linearly opposite to the torsion force of the positive stiffness spring 10, which is also called a negative stiffness spring. Figure 8 and Figure 9 The superimposed line of the positive and negative stiffness springs is the torque output at different torsion angles. The superimposed line of the positive and negative stiffness springs in the figure is the reference torque in the constant force range. The figure shows the output torque diagram of the positive stiffness spring 10 after adjustment when the required torque is greater than the reference torque.

[0041] In this embodiment, each rotating connection is provided with bearings, gaskets and other necessary devices known to those skilled in the art, and they will not be described in detail here.

[0042] In summary, when the adjustable constant force clamp based on torsional quasi-zero stiffness is clamping an object, the torque required by the gear 16 is calculated according to the required clamping force. When the torque is greater than the reference torque, the output end of the motor 2 13 drives the worm 14 to rotate, and the worm 14 drives the worm wheel 12 to rotate, so that the lower support plate 11 rotates counterclockwise and the inner ring magnetic frame 7 rotates clockwise. The output end of the motor 2 13 stops rotating, and the worm wheel 12 and the worm 14 form a self-locking. The output end of the motor 1 2 drives the torque input shaft 3 to rotate, and the outer ring magnetic frame 5 drives the inner ring magnetic frame 7 to rotate through the magnetic spring. When the clamping claw 18 stops moving after clamping the object, the inner ring magnetic frame 7 and the outer ring magnetic frame 5 are twisted relative to each other, and the positive stiffness spring 10 is twisted at the same time. When the twisting degree of the magnetic spring and the positive stiffness spring 10 reaches between 30 degrees and 60 degrees, the torque output from the torque output shaft 4 to the gear 16 is constant. At this time, the motor 2 detects that the output current is constant, and then locks the torque output shaft 4, and then performs constant force clamping through the torque output by the magnetic spring and the positive stiffness spring 10.

[0043] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An adjustable constant force clamp based on torsional quasi-zero stiffness, comprising an external frame (1), a motor (2) and a clamping mechanism, wherein the motor (2) is fixedly mounted on the external frame (1), and the clamping mechanism is arranged on an end of the external frame (1) away from the motor (2), characterized in that: Also includes: A torque input shaft (3) is rotatably connected to the external frame (1), and the torque input shaft (3) is transmission-connected to the output end of the motor 1 (2); a torque output shaft (4) rotatably connected to one end of the outer frame (1) away from the torque output shaft (4), the torque output shaft (4) being connected to the clamping mechanism, and the torque input shaft (3) and the torque output shaft (4) coaxially rotating; a constant force output mechanism, the two ends of which are respectively connected to the torque input shaft (3) and the torque output shaft (4), the constant force output mechanism being used to flexibly connect the torque input shaft (3) and the torque output shaft (4) and output a constant torque to the torque output shaft (4); A force adjustment mechanism is connected to the torque input shaft (3), and the force adjustment mechanism is rotationally connected to the torque output shaft (4). The force adjustment mechanism is used to adjust the torque outputted from the constant force output mechanism to the torque input shaft (3).

2. The adjustable constant force clamp based on torsional quasi-zero stiffness according to claim 1, characterized in that: The constant force output mechanism comprises: An outer ring magnetic frame (5) is fixedly connected to the torque input shaft (3), the outer ring magnetic frame (5) is arranged in a circular shape, and a plurality of outer ring magnets (6) are arranged on the outer ring magnetic frame (5); An inner ring magnetic frame (7) is fixedly connected to the torque output shaft (4), the inner ring magnetic frame (7) is arranged in a ring shape, the inner ring magnetic frame (7) extends into the outer ring magnetic frame (5), and a plurality of inner ring magnets (8) are arranged on the inner ring magnetic frame (7); A support sleeve (9) is fixedly connected to the center of the outer ring magnetic frame (5), the support sleeve (9) passes through the inner ring magnetic frame (7), and the support sleeve (9) is rotationally connected to the torque output shaft (4).

3. The adjustable constant force clamp based on torsional quasi-zero stiffness according to claim 2, characterized in that: A gap is left between the inner ring magnet (8) and the outer ring magnet (6), the inner ring magnet (8) and the outer ring magnet (6) are both arranged in a fan shape, the inner ring magnet (8) and the outer ring magnet (6) correspond to each other, and a plurality of the inner ring magnets (8) and a plurality of the outer ring magnets (6) are respectively arranged in a circular shape on the inner ring magnetic frame (7) and the outer ring magnetic frame (5).

4. The adjustable constant force clamp based on torsional quasi-zero stiffness according to claim 3, characterized in that: The force adjustment mechanism includes: A positive stiffness spring (10) is fixedly connected to the torque input shaft (3), and the positive stiffness spring (10) is sleeved on the outer ring magnetic frame (5); A lower supporting plate (11) is rotatably connected to one end of the inner ring magnetic frame (7) close to the torque output shaft (4), and one end of the positive stiffness spring (10) away from the torque input shaft (3) is fixedly connected to the lower supporting plate (11); A torsion assembly is arranged on a side of the lower support plate (11) away from the positive stiffness spring (10), and the torsion assembly is used to drive the positive stiffness spring (10) to torsion.

5. The adjustable constant force clamp based on torsional quasi-zero stiffness according to claim 4, characterized in that: The torsion assembly comprises: A worm gear (12) is fixedly mounted on the torque output shaft (4); There are multiple motors 2 (13), each of which is fixedly mounted on the lower support plate (11), and the multiple motors 2 (13) are arranged in a circular pattern; A plurality of worms (14) are provided, and the plurality of worms (14) are all rotatably connected to the lower support plate (11), and each of the worms (14) is transmission-connected to an output end of the second motor (13); The plurality of worms (14) are all meshed with the worm wheel (12).

6. The adjustable constant force clamp based on torsional quasi-zero stiffness according to claim 5, characterized in that: When the output end of the second motor (13) drives the worm (14) to rotate, the lower support plate (11) and the inner ring magnetic frame (7) can rotate relative to each other.

7. The adjustable constant force clamp based on torsional quasi-zero stiffness according to claim 6, characterized in that: The output end of the second motor (13) can rotate forward and reverse, and the lower support plate (11) can rotate in the clockwise direction and the counterclockwise direction.

8. The adjustable constant force clamp based on torsional quasi-zero stiffness according to claim 7, characterized in that: When the clamping mechanism clamps the object, the inner ring magnetic frame (7) and the lower support plate (11) stop rotating, and the outer ring magnetic frame (5) can rotate relative to the inner ring magnetic frame (7).

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