A high gripping capacity dexterous hand and robot

Abstract

The present application relates to the technical field of robots, and in particular to a dexterous hand with high grasping capacity, comprising a dexterous hand body, wherein the dexterous hand body comprises an outer constraint part, an inner constraint part, a grasping part and a driving part; the inner constraint part is arranged in the outer constraint part, the outer constraint part can move forward and backward along the direction of the inner constraint part, and the inner constraint part is used for constraining the grasping part; the grasping part is constrained by both the outer constraint part and the inner constraint part, and the grasping part can grasp an object; the driving part is arranged on the inner constraint part, and the driving part provides power to the grasping part; the outer constraint part is arranged on the dexterous hand body, the outer constraint part can move forward and backward along the direction of the inner constraint part, and the outer constraint part is simultaneously driven to move backward by the driving part, the outer constraint part moves forward, and the overall grasping capacity is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of robots, and in particular to a dexterous hand and a robot with high clamping capability. Background Art

[0002] In some robot usage scenarios, the robot will use its working part to grip and pick up objects. Most of these working parts are flexible dexterous hands with elastic steel sheets as the main body. They are mostly configured with four elastic steel sheets, one inner elastic steel sheet and one outer elastic steel sheet forming a finger. A rough object (such as a rubber pad) may be installed at the end of each finger to assist the dexterous hand in gripping objects, and the two fingers are symmetrical about the central axis of the dexterous hand.

[0003] For example, the Chinese patent publication number CN108214534B discloses an adaptive under-actuated robot gripper. In a dexterous hand made of a portion of elastic steel sheets, when the dexterous hand needs to perform a gripping task, the operator uses a rope or other driving method to pull the two inner elastic steel sheets toward the operator, generating a tensile force in the inner elastic steel sheets. At this time, the outer elastic steel sheet is compressed, and a force is also generated on the inner elastic steel sheet. The direction of this force forms an obtuse angle with the direction of the tensile force in the inner elastic steel sheet. After vector addition, a component force called the clamping force is obtained. This component force just makes the two fingers move toward each other, thus achieving gripping.

[0004] However, in actual work, when the two fingers are about to close, the angle between the forces in the inner and outer elastic steel sheets will tend to 180°, causing the clamping force to decrease rapidly as the two fingers close. This is not conducive to the dexterous hand gripping small and heavy objects. The dexterous hand has a limited opening angle, and when the length of the dexterous hand is limited, it is not conducive to it gripping large objects. Summary of the Invention

[0005] In view of the above problems, the present invention provides a dexterous hand and a robot with high gripping capability.

[0006] The adopted technical solution is: a dexterous hand with high gripping ability, comprising a dexterous hand body, wherein the dexterous hand body comprises an external constraint part, an internal constraint part, a gripping part and a driving part;

[0007] The inner restraining portion is arranged inside the outer restraining portion, and the outer restraining portion can move forward and backward along the direction of the inner restraining portion, and the inner restraining portion is used to restrain the clamping portion;

[0008] The clamping portion is constrained by both the outer constraining portion and the inner constraining portion, and the clamping portion can clamp an article;

[0009] The driving part is arranged on the inner restraining part, and provides power to the clamping part.

[0010] Optionally, the clamping portion includes symmetrically arranged dexterous hand mechanisms, and the two dexterous hand mechanisms are connected by an elastic steel sheet connector.

[0011] Optionally, the dexterous hand mechanism includes an outer elastic steel sheet and an inner elastic steel sheet, and one end of the outer elastic steel sheet is connected to one end of the inner elastic steel sheet, and a finger structure is provided at the connection point, and the other ends of the inner elastic steel sheets in the two dexterous hand mechanisms are connected to the elastic steel sheet connecting piece.

[0012] Optionally, the outer constraint portion includes a sleeve, in which a first through groove is provided, the inner constraint portion and the outer elastic steel sheet can be inserted into the first through groove, and the outer elastic steel sheet can contact the opening of the first through groove and apply outward pressure to the opening of the first through groove.

[0013] Optionally, the inner restraint portion includes a base, in which a second through-groove is provided, and the inner elastic steel sheet and the connector connected to the elastic steel sheet can be inserted into the second through-groove.

[0014] Optionally, the other end of the outer elastic steel sheet is bent into a horizontal section and connected to the outer wall of the base through the horizontal section.

[0015] Optionally, the driving unit includes a steering gear, a rotating shaft, a pull rope and a gear;

[0016] The steering gear is arranged below the base, and the power output end of the steering gear is connected to the rotating shaft;

[0017] The rotating shaft passes through the base and is connected to the gear located above the base, and the rotating shaft can drive the gear to rotate;

[0018] One end of the pull rope is wound around the shaft body of the rotating shaft, and the other end of the pull rope is connected to the elastic steel sheet connecting piece.

[0019] Optionally, a driving rack is further provided on the base, and the driving rack can engage with the gear. A first fixing hole is provided on the upper part of the sleeve, and the driving rack is connected to the sleeve by a bolt passing through the first fixing hole.

[0020] Optionally, the base is further provided with a guide groove and a guide block, one end of the guide block is inserted into the guide groove, and the other end of the guide block is connected to the second fixing hole provided on the side of the sleeve through a bolt;

[0021] The guide groove and the guide block are far away from the dexterous hand mechanism, and the guide groove is a straight line and parallel to the long side of the base.

[0022] Optionally, the finger structure includes a finger support and a finger, wherein the finger support is provided at the connection between the outer elastic steel sheet and the inner elastic steel sheet, and the fingers on the two dexterous hand mechanisms are arranged opposite to each other;

[0023] The finger support is provided with a mounting groove and a rotating shaft. The protruding end of the finger is inserted into the mounting groove and connected to the rotating shaft. The finger can rotate 15° to 20° on the rotating shaft.

[0024] The present application also provides a robot that uses the above dexterous hand with high gripping capability.

[0025] The benefits of the present invention include:

[0026] 1. An external constraint is provided on the dexterous hand body. The external constraint can move forward and backward along the direction of the internal constraint. The driving part simultaneously drives the gripping part to move backward and the external constraint to move forward, thereby improving the overall gripping ability.

[0027] 2. The drive unit uses a pull rope and a gear rack mechanism to drive the dexterous hand mechanism and the sleeve respectively, which can achieve the simultaneous driving of the movement of the two components using only one rotating shaft, maintaining the singleness of the driver, making the drive unit structure simple and cost-controllable. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is an axonometric view of a high-gripping-capacity dexterous hand in a clamping state;

[0029] Figure 2 This is an axonometric diagram of a dexterous hand with high gripping ability in a relaxed state;

[0030] Figure 3 De-sleeve isometric drawing for relaxed state;

[0031] Figure 4 Remove the sleeve and base axonometric drawing for the relaxed state;

[0032] Figure 5 This is the axonometric drawing of the drive unit;

[0033] Figure 6 This is a comparison chart of clamping and relaxation;

[0034] Figure 7 is the force analysis diagram;

[0035] Figure 8 Schematic diagram of finger structure;

[0036] Figure 9 for Figure 8 Schematic diagram of the cross section along AA.

[0037] The figure marks are: 1 is the outer elastic steel sheet, 1a is the clamping outer elastic steel sheet, 2 is the inner elastic steel sheet, 2a is the clamping inner elastic steel sheet, 3 is the elastic steel sheet connector, 4 is the pull rope, 5 is the rotating shaft, 6 is the finger support, 7 is the finger, 9 is the driving rack, 10 is the guide block, 11 is the base, 12 is the sleeve, 13 is the first fixing hole, 14 is the second fixing hole, 15 is the gear, 16 is the horizontal section, 17 is the guide groove, 18 is the installation groove, and 20 is the servo. DETAILED DESCRIPTION

[0038] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different perspectives and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features within these embodiments may be combined unless they conflict.

[0039] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. Therefore, the illustrations only show components relevant to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0040] like Figure 1 and Figure 2 As shown, a dexterous hand with high gripping ability includes a dexterous hand body, wherein the dexterous hand body includes an outer constraint part, an inner constraint part, a gripping part and a driving part;

[0041] The inner restraining portion is arranged inside the outer restraining portion, and the outer restraining portion can move forward and backward along the direction of the inner restraining portion, and the inner restraining portion is used to restrain the clamping portion;

[0042] The clamping portion is constrained by both the outer constraining portion and the inner constraining portion, and the clamping portion can clamp an article;

[0043] The driving part is arranged on the inner restraining part, and provides power to the clamping part.

[0044] The purpose of this design is to set an external constraint part on the dexterous hand body, which can move forward and backward along the direction of the internal constraint part, and simultaneously drive the clamping part to move backward and the external constraint part to move forward through the driving part, thereby improving the overall clamping ability.

[0045] In this embodiment, a specific structure of a clamping portion is provided, such as Figure 3 and Figure 4As shown, the clamping part includes a symmetrically arranged dexterous hand mechanism, and the two dexterous hand mechanisms are connected by an elastic steel sheet connector 3. The dexterous hand mechanism includes an outer elastic steel sheet 1 and an inner elastic steel sheet 2, and one end of the outer elastic steel sheet 1 is connected to one end of the inner elastic steel sheet 2, and a finger structure is provided at the connection. The other ends of the inner elastic steel sheets 2 in the two dexterous hand mechanisms are connected to the elastic steel sheet connector 3.

[0046] At the same time, this embodiment also provides a specific structure of an external constraint part, wherein the external constraint part includes a sleeve 12, and a first through groove is provided in the sleeve 12. The internal constraint part and the external elastic steel sheet 1 can be inserted into the first through groove, and the external elastic steel sheet 1 can contact the opening of the first through groove and apply outward pressure to the opening of the first through groove.

[0047] Furthermore, this embodiment also provides a specific structure of an internal constraint portion, wherein the internal constraint portion includes a base 11, and a second through groove is provided in the base 11, and the internal elastic steel sheet 2 and the elastic steel sheet connector 3 can be inserted into the second through groove.

[0048] At the same time, the other end of the outer elastic steel sheet 1 is bent into a horizontal section 16 and connected to the outer wall of the base 11 through the horizontal section 16 .

[0049] like Figure 5 As shown, this embodiment provides a specific structure of a driving unit, wherein the driving unit includes a steering gear 20, a rotating shaft 5, a pull rope 4 and a gear 15;

[0050] The steering gear 20 is provided below the base 11, and the power output end of the steering gear 20 is connected to the rotating shaft 5;

[0051] The rotating shaft 5 passes through the base 11 and is connected to the gear 15 located above the base 11. The rotating shaft 5 can drive the gear 15 to rotate;

[0052] One end of the pull rope 4 is wound around the shaft of the rotating shaft 5 , and the other end of the pull rope 4 is connected to the elastic steel sheet connector 3 .

[0053] In addition, a driving rack 9 is provided on the base 11, and the driving rack 9 can engage with the gear 15. A first fixing hole 13 is provided on the upper part of the sleeve 12, and the driving rack 9 is connected to the sleeve 12 by a bolt passing through the first fixing hole 13.

[0054] The purpose of this design is that the driving part uses a pull rope and a gear rack mechanism to drive the dexterous hand mechanism and the sleeve respectively, which can achieve the purpose of driving the movement of the two components at the same time using only one rotating shaft, maintaining the singleness of the driver, making the driving part structure simple and the cost controllable.

[0055] The whole dexterous hand works as follows: Figure 2In the relaxed state, the servo starts to work, causing the shaft to rotate. On the one hand, the shaft pulls the pull rope, so that the pull rope drives the elastic steel sheet connector to move toward the shaft. At this time, the inner elastic steel sheet bends inward, thereby driving the outer elastic steel sheet to deform and bulge. At the same time, the finger structures at the connection between the inner elastic steel sheet and the outer elastic steel sheet in the two dexterous hand mechanisms move toward each other to complete the clamping. On the other hand, the rotation drives the gear located above the base to rotate, and because the driving rack is engaged with it, the driving rack is connected to the sleeve through bolts, so that the gear drives the sleeve The sleeve moves in a direction opposite to that of the inner elastic steel sheet, adding a force to increase the gripping force when gripping small objects without adding any additional drive. Because this force and the elastic steel sheet's force originate from the same drive, the force must meet the following conditions: When the two fingers are about to close, the force consumes a certain amount of the drive's torque, and the gain in gripping force is significantly greater than the gain in gripping force from the elastic steel sheet. Furthermore, the design allows the outer elastic steel sheet to bulge outward under pressure, and the sleeve moves just enough to contact the bulging portion of the outer elastic steel sheet. As the sleeve continues to move forward and the outer elastic steel sheet continues to bulge outward, it begins to apply pressure to the outer elastic steel sheet, which significantly increases the gripping force, thereby improving the dexterous hand's ability to grip small or difficult-to-grasp objects.

[0056] To verify this, Figure 7 As shown in FIG, a stress analysis is performed on the entire process. Symbols with “'” in the figure belong to the stress analysis of the pull rope-inner elastic steel sheet structure, and symbols without “'” belong to the stress analysis of the sleeve-outer elastic steel sheet.

[0057] From the force analysis results of the pull rope-internal elastic steel sheet structure in the figure, it can be seen that when the dexterous hand is about to close, the clamping force F 夹 's contribution is very small, less than 0.15 times the tension in the internal elastic steel sheet, that is, less than 0.075 times the tension in the pull rope.

[0058] Then the force analysis of the sleeve-external elastic steel sheet structure is carried out by force decomposition and moment balance. The results show that the clamping force F 夹 The contribution is about 1.2 times the vertical component of the sleeve on the single-sided external elastic steel sheet, which is 0.6 times the driving force of the gear rack on the sleeve.

[0059] As can be seen, when the dexterous hand is about to close, the sleeve's contribution to the gripping force is dozens of times greater than that of the pull rope-internal elastic steel sheet structure. Therefore, the sleeve structure significantly improves the gripping force of the dexterous hand when grasping small objects.

[0060] In addition, by increasing the stiffness of the outer elastic steel sheet and reducing the stroke of the sleeve, that is, increasing the reduction ratio, it is possible to further increase the clamping force when clamping small items by increasing the driving force of the motor on the sleeve.

[0061] At the same time, the drive unit can realize automatic distribution of the motor torque. When the sleeve contacts the outer spring steel sheet and begins to apply pressure, the resistance to the sleeve movement increases rapidly, and most of the motor torque will be used to provide power to the sleeve. This principle enables the motor torque to automatically flow to the part that is most conducive to increasing the clamping force.

[0062] In this embodiment, the base 11 is further provided with a guide groove 17 and a guide block 10. One end of the guide block 10 is inserted into the guide groove 17, and the other end of the guide block 10 is connected to the second fixing hole 14 provided on the side of the sleeve 12 by a bolt.

[0063] The guide groove 17 and the guide block 10 are far away from the dexterous hand mechanism, and the guide groove 17 is a straight line and parallel to the long side of the base 11.

[0064] The purpose of this design is to ensure that the sleeve moves linearly along the axis of the base through the cooperation of the guide groove and the guide block.

[0065] And in Figure 6 In the figure, it can be clearly seen that from the natural relaxation state to the fully clamped state, the difference between the outer elastic steel sheet 1 and the inner elastic steel sheet 2 and the clamped outer elastic steel sheet 1a and the clamped inner elastic steel sheet 2a is that the fingertip structure will rotate about 60°.

[0066] like Figures 8 and 9 As shown, the finger structure includes a finger support 6 and a finger 7. The finger support 6 is provided at the connection between the outer elastic steel sheet 1 and the inner elastic steel sheet 2, and the fingers 7 on the two dexterous hand mechanisms are arranged opposite to each other.

[0067] The finger support 6 is provided with a mounting groove 18 and a rotation axis. The protruding end of the finger 7 is inserted into the mounting groove 18 and connected to the rotation axis. The finger 7 can rotate 15° to 20° on the rotation axis.

[0068] In actual use, the single-sided rubber pad structure on the fingertips can be replaced with two surfaces with a 45° angle between them. The two gripping contact surfaces at a 45° angle and the small range of free rotation structure together ensure that the fingertips of the dexterous hand can grasp objects with parallel or nearly parallel contact surfaces throughout the entire gripping stroke. A rotating shaft is then installed between the rubber pad and the steel sheet, and 15° to 20° of movable space is reserved for the fingertips of the rubber pad to ensure that a set of surfaces remain parallel or nearly parallel throughout the entire gripping stroke of the dexterous hand. At the same time, this design takes into account both the stability and gripping ability of the fingertips during gripping. The mobility of the fingertips around the rotation axis will impair gripping stability, but the impact of only 10° of movable space on stability is negligible. The mobility around the rotation axis and the two-sided design at a 30° angle ensure the parallelism of the fingertips, thereby ensuring the gripping ability of the dexterous hand.

[0069] It should be pointed out that the dexterous hand described in this embodiment is actually a clamping claw structure.

[0070] In this embodiment, a robot is also provided, which structurally uses the dexterous hand with high gripping ability in the above embodiments.

[0071] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent replacements for some of the technical features therein. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A dexterous hand with high gripping ability, comprising a dexterous hand body, characterized in that: The dexterous hand body includes an external constraint part, an internal constraint part, a clamping part and a driving part; The inner restraining portion is arranged inside the outer restraining portion, and the outer restraining portion can move forward and backward along the direction of the inner restraining portion, and the inner restraining portion is used to restrain the clamping portion; The clamping portion is constrained by both the outer constraining portion and the inner constraining portion, and the clamping portion can clamp an article; The driving portion is provided on the inner restraining portion, and the driving portion provides power to the clamping portion; The clamping portion comprises symmetrically arranged dexterous hand mechanisms, and the two dexterous hand mechanisms are connected via an elastic steel sheet connector (3); The dexterous hand mechanism comprises an outer elastic steel sheet (1) and an inner elastic steel sheet (2), one end of the outer elastic steel sheet (1) is connected to one end of the inner elastic steel sheet (2), and a finger structure is provided at the connection point, and the other ends of the inner elastic steel sheets (2) in the two dexterous hand mechanisms are both connected to the elastic steel sheet connector (3); The outer constraint portion comprises a sleeve (12), a first through-groove is provided in the sleeve (12), the inner constraint portion and the outer elastic steel sheet (1) can be inserted into the first through-groove, and the outer elastic steel sheet (1) can contact the opening of the first through-groove and apply pressure outward to the opening of the first through-groove; The inner restraining portion comprises a base (11), wherein a second through-groove is provided in the base (11), and the inner elastic steel sheet (2) and the connecting member (3) connected to the elastic steel sheet can both be inserted into the second through-groove; The driving unit includes a steering gear (20), a rotating shaft (5), a pull rope (4) and a gear (15); The steering gear (20) is arranged below the base (11), and the power output end of the steering gear (20) is connected to the rotating shaft (5); The rotating shaft (5) passes through the base (11) and is connected to the gear (15) located above the base (11), and the rotating shaft (5) can drive the gear (15) to rotate; One end of the pull rope (4) is wound around the shaft of the rotating shaft (5), and the other end of the pull rope (4) is connected to the elastic steel sheet connector (3); a driving rack (9) is also provided on the base (11), and the driving rack (9) can engage with the gear (15); a first fixing hole (13) is provided on the upper part of the sleeve (12), and the driving rack (9) is connected to the sleeve (12) by a bolt passing through the first fixing hole (13).

2. A dexterous hand with high gripping capability according to claim 1, characterized in that: The other end of the outer elastic steel sheet (1) is bent into a horizontal section (16), and is connected to the outer wall of the base (11) via the horizontal section (16).

3. The dexterous hand with high gripping ability according to claim 1, characterized in that: The base (11) is further provided with a guide groove (17) and a guide block (10), one end of the guide block (10) is inserted into the guide groove (17), and the other end of the guide block (10) is connected to a second fixing hole (14) provided on the side of the sleeve (12) via a bolt; The guide groove (17) and the guide block (10) are away from the dexterous hand mechanism, and the guide groove (17) is a straight line and parallel to the long side of the base (11).

4. The dexterous hand with high gripping ability according to claim 1, characterized in that: The finger structure comprises a finger support (6) and a finger (7), wherein the finger support (6) is arranged at the connection between the outer elastic steel sheet (1) and the inner elastic steel sheet (2), and the fingers (7) on the two dexterous hand mechanisms are arranged opposite to each other; The finger support (6) is provided with a mounting groove (18) and a rotating shaft. The protruding end of the finger (7) is inserted into the mounting groove (18) and connected to the rotating shaft. The finger (7) can rotate 15° to 20° on the rotating shaft.

5. A robot, characterized in that: A dexterous hand with high gripping capability comprising the device of any one of claims 1 to 4.

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