A self-adapting, passive source driven flexible gripper

Abstract

The application discloses a flexible clamp without power source driving for adaptive clamping, belongs to the technical field of precise device taking and placing, and has symmetrical elastic arms which are composed of three-section thin-wall plates, wherein the thin walls are provided with a first fixed block and a second fixed block which are relatively thick, and a clamping claw is fixed on the second fixed block; through deformation of a connection position of the second fixed block and the thin-wall plate, the second fixed block drives the clamping claw to open and clamp an object. The three-section thin-wall plate structure utilizes a bistable structure principle, and through torque, the three-section thin-wall plate is deformed, thereby reversibly switching between two stable states for multiple times, and can be applied to scenes such as precise microneedle sampling. Since manual needle replacement operation is avoided, the precision, quality and efficiency of sampling are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of precision device pick and place technology, and particularly to a flexible clamp for adaptive clamping without power source driving. BACKGROUND

[0002] In the process of precision device pick and place, the target device is generally positioned by manual method, picked up by electric clamp, then positioned at the target area, adjusted in spatial posture, and placed by electric clamp. In the biomedical field, precision microneedles are often used to sample target biological tissues. Currently, the precision microneedles are installed at the specified sampling position by manual method. However, due to the limited operation space, the operation is extremely time-consuming and laborious, resulting in low sampling efficiency and difficulty in batch operation. Moreover, the manual method is easily affected by human factors, and cannot guarantee the installation precision and operation repeatability, thereby affecting the sampling quality.

[0003] In addition, the electric clamp needs to be adjusted between joints to adapt to the shape profile of the device to be clamped, so that a power source such as a motor needs to be introduced, increasing the complexity and difficulty of system control, and the motor lubricating oil is easy to volatilize and pollute the biological sample. Therefore, the above method is often not suitable for the biomedical field which is sensitive to environmental pollution. SUMMARY

[0004] The present application provides a flexible clamp for adaptive clamping without power source driving, which solves the unstable quality of manual needle sampling in the prior art, and improves the precision, quality and efficiency of sampling.

[0005] The present application provides a flexible clamp for adaptive clamping without power source driving, which solves the unstable quality of manual needle sampling in the prior art, and improves the precision, quality and efficiency of sampling.

[0006] The support part includes a first support plate, a second support plate and two symmetrically arranged elastic arms arranged in parallel, the elastic arms have opposite first ends and second ends, the first ends are connected with the first support plate, and the second ends are connected with the second support plate, the elastic arms include a thin wall, a first fixed block and a second fixed block, the first fixed block and the second fixed block are arranged on the thin wall, the first fixed block is arranged on one side close to the first support plate, the second fixed block is arranged on one side close to the second support plate, the first fixed block and the second fixed block divide the thin wall into three thin wall plates arranged side by side along the length direction of the thin wall, and the thickness of the second fixed block is greater than the thickness of the thin wall plate.

[0007] The clamping part comprises two symmetrically arranged clamping claws in cantilever structure, the fixed ends of the clamping claws are connected with the second fixed block, the cantilever ends of the clamping claws have clamping surfaces, and the clamping surfaces of the two clamping claws are opposite.

[0008] Further, the structural parameters of the elastic arm satisfy the following conditions:

[0009]

[0010] wherein L is an effective force arm, l is half of the length of the elastic arm, b is the width of the thin-walled plate, h is the thickness of the thin-walled plate, R is the rotation radius of the clamping end relative to the torsion center of the thin-walled plate, w is the displacement of the clamping end relative to the initial state after clamping the clamped object, E is the elastic modulus of the thin-walled material, and F is the force of the clamping end on the clamped object.

[0011] Further, the ratio of the thickness of the second fixed block to the thickness of the thin-walled plate is greater than 3.

[0012] Further, the clamping surface and the end surface of the cantilever end have a rounded corner.

[0013] Further, the clamping surface of the clamping claw has a clamping groove, and the clamping groove has openings on the clamping surface and the arc surface where the rounded corner is located.

[0014] Further, the clamping groove comprises a base accommodating cavity and a body accommodating cavity, the distance from the bottom surface of the base accommodating cavity to the clamping surface is greater than the distance from the bottom surface of the body accommodating cavity to the clamping surface, so as to form a stepped surface.

[0015] Further, the support part further comprises a connecting plate connecting the middle part of the first support plate and the middle part of the second support plate.

[0016] Further, the support part and the clamping part of the flexible clamp are detachably connected.

[0017] Further, the material of the flexible clamp is any one of titanium alloy, beryllium bronze or aluminum alloy.

[0018] Further, the material of the flexible clamp is a non-metallic material with a yield strength to elastic modulus ratio greater than 30x10-3.

[0019] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0020] The flexible clamp is composed of symmetrical elastic arms, the elastic arms are composed of three-section thin-walled plates, thick first fixed blocks and second fixed blocks exist on the thin-walled plates, clamping claws are fixed on the second fixed blocks, and the second fixed blocks drive the clamping claws to open and clamp objects by deformation of the connection parts of the second fixed blocks and the thin-walled plates. The three-section thin-walled plate structure utilizes the principle of bistable structure, and is reversibly switched between two stable states by torque to make the three-section thin-walled plate deform, so that the manual needle changing is avoided, and the sampling precision and quality are improved. Meanwhile, the taking and placing mode without power source driving can avoid the introduction of the power source to pollute the biological tissue, so that the application can be applied to the biomedical field with higher requirements. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A structure schematic diagram of the flexible clamp provided for the embodiment of the application is shown in the figure.

[0022] Fig. 2(a) is a schematic diagram of simplifying the flexible clamp into a pseudo-rigid body model;

[0023] Fig. 2(b) is a schematic diagram of force analysis of the pseudo-rigid body model;

[0024] Fig. 2(c) is an enlarged view of a part of the flexible clamp;

[0025] Figure 3 A structure schematic diagram of another flexible clamp without power source driving provided for the embodiment of the application is shown in the figure.

[0026] Fig. 4(a) is a schematic diagram of the flexible clamp clamping microneedles provided for the embodiment of the application;

[0027] Fig. 4(b) is a structure schematic diagram of the microneedles;

[0028] Fig. 5(a) is a sectional view of the flexible clamp in Fig. 4(a);

[0029] Fig. 5(b) is a top view of Fig. 5(a);

[0030] Figure 6 A schematic diagram of the flexible clamp clamping a glass slide provided for the embodiment of the application is shown in the figure.

[0031] Figure 7 A sectional view of the flexible clamp in Fig. 3 is shown in the figure. Figure 6 A sectional view of the flexible clamp in Fig. 3 is shown in the figure. DETAILED DESCRIPTION

[0032] To make the purpose, technical scheme and advantages of the application more clear, the following will further describe the embodiments of the application in combination with the drawings.

[0033] Figure 1 A structure schematic diagram of a flexible clamp without power source driving provided for the embodiment of the application is shown in the figure. Figure 1As shown, the flexible clamp comprises a support part 100 and a clamping part 200.

[0034] The support part 100 comprises a first support plate 101, a second support plate 102 and two symmetrically arranged elastic arms 110, the elastic arms 110 have opposite first ends 111 and second ends 112, the first ends 111 are connected with the first support plate 101, the second ends 112 are connected with the second support plate 102, the elastic arms 110 comprise a thin wall, a first fixed block 113 and a second fixed block 114, the first fixed block 113 and the second fixed block 114 are arranged on the thin wall, the first fixed block 113 is arranged on one side close to the first support plate 101, the second fixed block 114 is arranged on one side close to the second support plate 102, the first fixed block 113 and the second fixed block 114 divide the thin wall into three thin wall plates 115 arranged side by side along the length direction of the thin wall, the thickness of the second fixed block 114 is greater than the thickness of the thin wall plate 115.

[0035] The clamping part 200 comprises two symmetrically arranged clamping claws 210, the clamping claws 210 are cantilever structures, the fixed ends 211 of the clamping claws are connected with the second fixed block 114, the cantilever ends 212 of the clamping claws have clamping surfaces 213, the clamping surfaces 213 of the two clamping claws 210 are opposite.

[0036] The flexible clamp is composed of symmetric elastic arms 110, the elastic arms 110 are composed of three-section thin wall plates, there are thicker first fixed blocks 113 and second fixed blocks 114 on the thin wall, the clamping claws 210 are fixed on the second fixed blocks 114, and the second fixed blocks 114 drive the clamping claws 210 to open and clamp the clamped object through the deformation of the connection between the second fixed blocks 114 and the thin wall plates 115.

[0037] The bistable structure means that the structural system has two stable equilibrium states, when the structural system changes, only a certain force is needed to make it overcome the energy barrier, and the structural system will be deformed into another stable low-energy state. And because the energy required to maintain this state is low, even if disturbed by the outside world (the outside disturbance is less than the critical value), the structural system can still maintain this state. The three-section thin wall plate structure in the embodiment utilizes the principle of bistable structure, and through torque, the three-section thin wall plate produces deformation, thereby reversibly switching between the initial state (non-clamping state) and the clamping state, which are two stable equilibrium states.

[0038] The thin wall plate is thin and easy to produce bending deformation, so it is equivalent to a flexible hinge; and the first fixed block and the second fixed block are thicker relative to the thin wall, and can be regarded as a rigid body, so it is equivalent to a rigid link; in theoretical analysis, it is idealized to consider only the bending deformation of the thin wall.

[0039] When clamping, the flexible clamp is in the initial state and moves towards the clamped object. When the clamped object contacts the clamping surface 213, a force is generated and transmitted to the flexible hinge, causing it to bend inward and deform, so that the clamping jaws 210 open in the x-axis direction, the clamped object is clamped by the clamping surface 213 of the clamping jaws 210, and the clamping state is achieved to complete the clamping. When exiting the clamping, the clamped object is only installed on the sampling device, the flexible clamp retreats, the clamped object and the clamping jaws 210 generate extrusion force again, and the flexible hinge is bent and deformed, the clamping jaws 210 open in the x-axis direction, so as to release the clamped object, and return to the initial state.

[0040] Figure 2(a) is a schematic diagram of simplifying the flexible clamp into a pseudo-rigid body model. The model simplifies the clamp into a way of connecting a rigid body simply supported beam (second fixed block) and a hinge (thin-walled plate) to analyze the force, and determines the structural parameters of the elastic arm according to the force when the clamped object is taken and the displacement of the clamping surface and the thin-walled material.

[0041] Referring to Figures 2(b) and 2(c):

[0042] The torque M that causes the thin-walled plate to bend and deform is: M = FL

[0043] Where F is the force when the needle is taken, and the direction is affected by the geometric parameters of the circular arc: L is the effective force arm.

[0044] Therefore, the maximum stress σ of the thin-walled plate can be obtained max The rotation angle θ is:

[0045]

[0046]

[0047] Where E is the elastic modulus of the thin-walled material, W is the bending modulus of the cross section of the thin-walled plate, I is the cross-sectional moment of inertia of the thin-walled plate, b is the width of the thin-walled plate, h is the thickness of the thin-walled plate, and l is half the length of the elastic arm.

[0048]

[0049]

[0050] Finally, the rotation angle is equivalent to the displacement w of the clamping end relative to the initial state when the clamping end is in the clamping state.

[0051]

[0052] Where R is the rotation radius of the clamping end relative to the torsion center of the thin-walled plate.

[0053] Combining the above formula, the structural parameters of the elastic arm satisfy the following conditions:

[0054]

[0055] wherein L is the effective arm length, l is half of the elastic arm length, b is the width of the thin-walled plate, h is the thickness of the thin-walled plate, R is the radius of rotation of the clamping end relative to the torsion center of the thin-walled plate, w is the displacement of the clamping end in the clamping state relative to the initial state, E is the elastic modulus of the thin-walled material, and F is the force of the clamping end on the clamped object.

[0056] In the calculation, the displacement w of the clamping end in the clamping state relative to the initial state, the elastic modulus E of the thin-walled material, and the force F of the clamping end on the clamped object can be determined according to the clamping requirements and the material, and the structural parameter relationship of the elastic arm 110 is obtained, and then the best parameters are selected by simulation analysis.

[0057] Optionally, the width of the second fixed block is consistent with the thickness of the whole clamping jaw, and the thickness depends on the height of the contact groove of the clamping end and the workpiece. The thickness ratio of the second fixed block to the thin-walled plate should be greater than 3 to ensure that the fixed block can be regarded as a rigid body during deformation, and the deformation mainly occurs on the thin-walled plate. The width of the second fixed block can be 10 mm, and the thickness of the first fixed block 113 can be 3 mm. For easy processing, the first fixed block and the second fixed block can be the same.

[0058] As shown in FIG. 2, the clamping jaw 210 is provided with a clamping surface 213, and the clamping surface 213 is provided with a clamping groove 215. Figure 3 As shown in FIG. 2, the clamping surface 213 of the clamping jaw 210 and the end surface of the cantilever end 212 have a chamfer 214, so that when the clamped object is placed between the two clamping surfaces 213, the impact force of the clamped object on the clamping jaw 210 generates a component force along the x direction, so that the two clamping jaws 210 can be better stressed to open.

[0059] In order to facilitate the clamping of different clamped objects, the clamping surface 213 of the clamping part 200 can be designed with different clamping grooves 215, and the clamping groove 215 has openings on the clamping surface 213 and the arc surface where the chamfer 214 is located, so as to facilitate the clamping and release of the clamped object.

[0060] In some embodiments, as shown in FIG. 4(a), the clamped object can be a microneedle. Specifically, as shown in FIG. 4(b), the microneedle includes a body 301 and a base 302, and in order to ensure that the sample is not contaminated, the flexible clamp can clamp the base 302 part. As shown in FIG. 5(a) and FIG. 5(b), the clamping groove 215 includes a base accommodating cavity 2151 and a body accommodating cavity 2152, and the distance L1 from the bottom surface of the base accommodating cavity 2151 to the clamping surface 213 is greater than the distance L2 from the bottom surface of the body accommodating cavity 2152 to the clamping surface 213, so as to form a stepped surface 2153 to increase the stability of the microneedle clamping. Specifically, the shapes of the base accommodating cavity 2151 and the body accommodating cavity 2152 can be adjusted according to the shapes of the microneedle base and body, and the present application is not limited.

[0061] Optionally, the bottom surface of the base accommodating cavity and the arc surface where the chamfer 214 is located have a transition arc surface 2154, so as to reduce the resistance when the microneedle is taken out.

[0062] In some embodiments, as shown in Figure 6 The clamping object can be a glass slide. Figure 7 To Figure 6 The cross-sectional view shows that the clamping surface 213 of the clamping part 200 is provided with a clamping groove corresponding to the shape of the glass slide, and the clamping groove has an opening on the clamping surface 213 and the arc surface where the chamfer 214 is located, so as to insert the glass slide.

[0063] Optionally, the material of the flexible clamp is any metal material such as titanium alloy, beryllium bronze or aluminum alloy, and the material of the flexible clamp is a non-metallic material with a yield strength to elastic modulus ratio greater than x, such as polypropylene, nylon polysilicon or photosensitive resin.

[0064] Optionally, the flexible clamp can be integrally formed with the support part 100 and the clamping part 200, or the support part 100 and the clamping part 200 can be detachably connected, so that the clamping part 200 with different clamping grooves can be switched according to different application scenarios.

[0065] In some embodiments, the shape of the clamping groove on the clamping part 200 is relatively complex, and 3D printing technology can be selected, and the material cooperating with the 3D printing technology can be a material with a small elastic modulus such as ABS, nylon or photosensitive resin, so that the clamping jaw 210 is easy to open.

[0066] In some embodiments, the support part 100 further comprises a connecting plate 103 connecting the middle part of the first support plate 101 and the middle part of the second support plate 102, so as to increase the rigidity of the whole support part 100. It can be understood that the 3D printing material is mostly plastic and resin, which has low rigidity and is easy to deform. When working, it is easy to deform and tilt under stress, which affects the needle taking operation. The connecting plate can be added to keep stable; if a metal material is used to process the clamping jaw by wire cutting, the rigidity is large and it is not easy to deform, and there is no need to add a connecting plate.

[0067] The above only describes optional embodiments of the present application and does not limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A self-adapting gripped, unpowered source driven flexible gripper, characterized by, The flexible clamp comprises: The support part comprises a first support plate, a second support plate and two symmetrically arranged elastic arms, the elastic arms have opposite first ends and second ends, the first ends are connected with the first support plate, the second ends are connected with the second support plate, the elastic arms comprise a thin wall, a first fixing block and a second fixing block, the first fixing block and the second fixing block are arranged on the thin wall, the first fixing block is arranged on one side close to the first support plate, the second fixing block is arranged on one side close to the second support plate, the first fixing block and the second fixing block divide the thin wall into three thin wall plates arranged side by side along the length direction of the thin wall, and the thickness of the second fixing block is greater than the thickness of the thin wall plate. The clamping part comprises two symmetrically arranged clamping claws, the clamping claws are cantilever structures, the fixed ends of the clamping claws are connected with the second fixing block, the cantilever ends of the clamping claws have clamping surfaces, and the clamping surfaces of the two clamping claws are opposite.

2. The flexible gripper of claim 1, wherein, The structural parameters of the elastic arm satisfy the following conditions: Wherein, L is the effective arm, l is half of the elastic arm length, b is the thin wall plate width, h is the thin wall plate thickness, R is the rotation radius of the clamping end relative to the torsion center of the thin wall plate, w is the displacement of the clamping end in the clamping state relative to the initial state, E is the elastic modulus of the thin wall material, and F is the force of the clamping end on the clamped object.

3. The flexible gripper of claim 1, wherein, The ratio of the thickness of the second fixing block to the thickness of the thin wall plate is greater than 3.

4. The flexible gripper of claim 1, wherein, The clamping surface and the end surface of the cantilever end have a chamfered corner.

5. The flexible gripper of claim 4, wherein, The clamping surface of the clamping claw has a clamping groove, and the clamping groove has openings on the clamping surface and the arc surface where the chamfered corner is located.

6. The flexible gripper of claim 5, wherein, The clamping groove comprises a base accommodating cavity and a body accommodating cavity, the distance from the bottom surface of the base accommodating cavity to the clamping surface is greater than the distance from the bottom surface of the body accommodating cavity to the clamping surface, so as to form a stepped surface.

7. The flexible gripper of any one of claims 1-6, wherein, The support part further comprises a connecting plate connecting the middle part of the first support plate and the middle part of the second support plate.

8. The flexible gripper of any one of claims 1-6, wherein, The support part and the clamping part of the flexible clamp are detachably connected.

9. The flexible gripper of any one of claims 1-6, wherein, The material of the flexible clamp is any one of titanium alloy, beryllium bronze or aluminum alloy.

10. The flexible gripper of any one of claims 1-6, wherein, The material of the flexible clamp is a non-metallic material with a yield strength to elastic modulus ratio greater than 30 x 10 -3 .

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