A robot flexible clamping device based on multi-level flexible mechanism design

Abstract

The application discloses a robot flexible clamping device based on a multilevel flexible mechanism design, which comprises a base, multilevel flexible claws and a clamping driving mechanism; a plurality of sets of the multilevel flexible claws are arranged in a circle on the base; each set of the multilevel flexible claws comprises a first clamping claw and a second clamping claw; the first clamping claw and the second clamping claw are connected through an elastic connecting piece; a clamping end is arranged on the clamping claw, and the clamping ends of the first clamping claw and the second clamping claw constitute a clamping opening of the multilevel flexible claw; the clamping driving mechanism is used for driving the elastic connecting piece to move downward, so as to make the clamping ends of the first clamping claw and the second clamping claw rotate towards each other with the elastic connecting piece as a rotating fulcrum, and realize a clamping action. The robot flexible clamping device can realize self-adaptive grabbing of clamping objects with different sizes and irregular shapes, has high universality and practicability, and is favorable for mass production.

Description

Technical Field

[0001] This invention belongs to the field of robotics, specifically relating to a flexible gripping device for robots based on a multi-level flexible mechanism design. Background Technology

[0002] Currently, robots are increasingly used in fields such as intelligent manufacturing, home services, and fruit and vegetable harvesting. In the current application environment, the robot end effector needs to plan the correct operating actions according to the characteristics of the object, such as its hardness, surface texture, and spatial shape, in order to ensure that the object being operated does not fall, slip, or break.

[0003] Robot end effectors generally employ two methods to complete tasks. One method uses a biomimetic mechanism mimicking the structure of a human hand, typically featuring multiple joints, multiple degrees of freedom, and multiple motors for driving complex grasping movements. However, this structure is overly complex, making servo control difficult and resulting in high manufacturing costs. The other method uses a traditional rigid gripper, primarily employing motors or hydraulic / pneumatic mechanisms to open and close the gripper. However, its rigid contact requires precise control of the gripping force, placing high demands on the precision of the gripper's control algorithm. Even minor errors can cause crushing damage to the object. Furthermore, slippage frequently occurs when gripping hard and smooth objects, significantly reducing the gripper's versatility and practicality. Additionally, if the gripper's rigidity is too high, it can generally only grasp objects with a single, regular shape, failing to grasp irregularly shaped objects, resulting in poor compatibility. Therefore, the rigid grippers widely used in current production suffer from poor versatility, high manufacturing costs, and insufficient flexibility. Poor versatility necessitates frequent replacement of clamping devices for operation, which is uneconomical; high manufacturing costs hinder industrial application; insufficient flexibility makes rigid clamps prone to damaging the clamped objects, failing to meet clamping requirements.

[0004] Most current two-dimensional planar grippers only have two-point contact when gripping objects, making it difficult to stably grip irregularly shaped micro-objects. To achieve the gripping of irregularly shaped micro-objects, multi-point contact is required when gripping the object, and 3D micro-grippers can meet this requirement.

[0005] Flexible mechanisms are a new type of mechanism that uses the elastic deformation of flexible components to transmit and convert motion, force, or energy. Flexible mechanisms offer advantages such as frictionlessness, lubrication-free operation, integrated manufacturing, and high motion sensitivity. These advantages make them suitable for gripper structural design, enabling the clamping and manipulation of objects, and allowing for multi-dimensional spatial clamping operations. Furthermore, the integrated molding design eliminates the need for assembly and periodic replacement of worn parts, thus facilitating efficient robot operation and faster completion of tasks.

[0006] Multi-level flexible mechanisms are an objective design method that incorporates the unique properties of flexible mechanisms. With the aim of product lightweighting, numerical calculations are used to obtain configuration designs that meet the formal characteristics and structural requirements. When applied to the lightweight design of products, this method effectively reduces the materials used and costs in product manufacturing.

[0007] With social development and continuous advancements in industrial technology, gripping devices are widely used in automated production lines, and are also evolving towards greater dexterity and flexibility. They can partially replace manual operation, grasping and transferring workpieces according to specific procedures, times, and positions required by the production process. Therefore, there is an urgent need to design a cost-effective, highly adaptable, universal robotic flexible gripper to meet the trend of mass production of grippers. Summary of the Invention

[0008] To overcome the shortcomings of existing technologies, this invention provides a robot flexible gripping device based on a multi-level flexible mechanism design. The robot flexible gripping device can adaptively grasp objects of different sizes and irregular shapes, and has strong versatility and practicality, thus facilitating mass production.

[0009] The technical solution of the present invention to solve the above-mentioned technical problems is:

[0010] A robot flexible gripping device based on a multi-level flexible mechanism includes a base, multi-level flexible claws mounted on the base, and a gripping drive mechanism for driving the gripping openings of the multi-level flexible claws to perform gripping actions.

[0011] The multi-level flexible claws are in multiple sets, and the multiple sets of multi-level flexible claws are arranged in a circle on the base; each set of multi-level flexible claws includes two symmetrically arranged clamping claws, which are a first clamping claw and a second clamping claw; wherein, the first clamping claw and the second clamping claw are connected by an elastic connector; the clamping claws are provided with clamping ends, and the clamping ends of the first clamping claw and the second clamping claw constitute the clamping opening of the multi-level flexible claw;

[0012] The clamping drive mechanism is used to drive the elastic connector to move downward, so as to cause the clamping ends of the first clamping claw and the second clamping claw to rotate in opposite directions with the elastic connector as the rotation fulcrum, so as to realize the clamping action.

[0013] Preferably, a buffer layer is provided on the clamping end.

[0014] Preferably, the clamping drive mechanism includes a linear motor and a push rod, wherein the linear motor is mounted on a motor mounting base, the main shaft of the linear motor is connected to the lower end of the push rod, and the upper end of the push rod is connected to the elastic connector; the base is provided with a clearance hole for avoiding the push rod.

[0015] Preferably, the upper side of the clamping claw is the clamping end, and the lower side is the support portion. The support portion includes a first elastic leg, a second elastic leg, and an elastic connecting rod. The first elastic leg is located on the outer side, while the second elastic leg is located on the inner side. The two ends of the elastic connecting rod are respectively connected to the bottom of the first elastic leg and the second elastic leg, thus forming a triangular structure. The tops of the first elastic leg and the second elastic leg intersect at the bottom of the clamping end. The end of the elastic connecting rod that intersects with the first elastic leg is fixed to the base, and the end of the elastic connecting rod that intersects with the second elastic leg is connected to a sliding sleeve. The sliding sleeve is provided with a sliding hole to avoid the push rod.

[0016] Preferably, the outer contour of the clamping end is arc-shaped, and the clamping end is provided with a plurality of through holes arranged along the outer contour of the clamping end.

[0017] Preferably, the multi-level flexible claw is formed using TPU material through an integrated injection molding process.

[0018] Preferably, the multi-level flexible claws are in two sets, with the two sets of multi-level flexible claws set at 90 degrees, and the two sets of multi-level flexible claws are formed using TPU material through an integrated injection molding process.

[0019] Preferably, the elastic connector is an elastic connection formed at the intersection of the first and second gripping claws in a multi-level, multi-group flexible claw.

[0020] Preferably, the ends of the elastic connecting rods in the first and second clamping claws of the multi-group, multi-level flexible claws intersect to form the sliding sleeve.

[0021] Preferably, the multi-level flexible claw is a multi-level single-cell configuration structure, and the multi-level single-cell configuration structure adopts an O-shaped configuration.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] 1. The robot flexible gripping device based on the multi-level flexible mechanism design of the present invention can adaptively grasp objects of different sizes and irregular shapes, and has strong versatility and practicality, thus facilitating mass production.

[0024] 2. The robot flexible gripping device based on the multi-level flexible mechanism design of the present invention adopts a spatially symmetrical structure of multiple sets of multi-level flexible claws arranged in a circle and perpendicular to each other. It has the characteristics of compact structure, uniform force distribution and wide applicability for grasping objects. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the robot flexible gripping device based on a multi-level flexible mechanism design according to the present invention.

[0026] Figure 2 This is a two-dimensional multi-level flexible topology diagram of a multi-level flexible claw.

[0027] Figure 3 This is a two-dimensional deformation diagram of a multi-level flexible topology structure of a multi-level flexible claw under load.

[0028] Figure 4 This is a three-dimensional multi-level flexible topological space structure diagram of a multi-level flexible claw.

[0029] Figure 5 This is a schematic diagram of the base structure.

[0030] Figure 6 This is a schematic diagram of the structure connecting the elastic connecting rod to the first elastic support leg.

[0031] Figure 7 This is a schematic diagram of the design of the robot flexible gripping device of the present invention.

[0032] Figure 8 This is a diagram showing the change in equivalent stiffness of the O-shaped unit cell as the characteristic dimensions change.

[0033] Figure 9 This is an enlarged view of the O-shaped configuration. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0035] See Figures 1-6 The robot flexible gripping device based on the multi-level flexible mechanism design of the present invention includes a base 4, a multi-level flexible claw 2 disposed on the base 4, and a gripping drive mechanism for driving the gripping opening of the multi-level flexible claw 2 to perform gripping actions.

[0036] See Figures 1-6, the multi-level flexible claws 2 are in multiple groups, and multiple groups of the multi-level flexible claws 2 are arranged in a circular pattern on the base 4; each group of multi-level flexible claws 2 includes two symmetrically arranged clamping claws, which are respectively a first clamping claw and a second clamping claw; wherein, the first clamping claw and the second clamping claw are connected by an elastic connecting member; a clamping end is provided on the clamping claw, and a buffer layer 1 is provided on the clamping end. The buffer layer 1 adopts a porous structure, so that it has a large flexibility characteristic, thereby ensuring that the damage to the clamped object during the contact process is minimized; the clamping ends of the first clamping claw and the second clamping claw constitute the clamping opening of the multi-level flexible claw 2; the clamping opening presents a "mouth" shape, which can adapt to the clamping operation of objects with irregular shapes. At the same time, since there are two groups of multi-level flexible claws 2 in this embodiment, that is, there are four clamping ends, when the robot flexible clamping device of the present invention clamps an object, the "mouth" - shaped clamping opening first contacts the clamped object at four evenly distributed points in space, and then contacts the clamped object at four evenly distributed surfaces in space, so that objects with irregular shapes can be stably clamped.

[0037] See Figures 1-6 , the clamping drive mechanism is used to drive the elastic connecting member to move downward, so as to cause the clamping ends of the first clamping claw and the second clamping claw to rotate towards each other with the elastic connecting member as the rotation fulcrum to achieve the clamping action. Among them, the clamping drive mechanism includes a linear motor 6 and a push rod 5. The linear motor 6 is installed on the motor mounting seat, the main shaft of the linear motor 6 is connected to the lower end of the push rod 5, and the upper end of the push rod 5 is connected to the elastic connecting member; an avoidance hole for avoiding the push rod 5 is provided on the base 4.

[0038] See Figures 1-6 , the upper side of the clamping claw is the clamping end, and the lower side is the supporting part. The supporting part includes a first elastic support foot 5, a second elastic support foot 6 and an elastic connecting rod 7. The first elastic support foot 5 is located on the outside, and the second elastic support foot 6 is located on the inside. The two ends of the elastic connecting rod 7 are respectively connected to the bottoms of the first elastic support foot 5 and the second elastic support foot 6 to form a triangular structure; the tops of the first elastic support foot 5 and the second elastic support foot 6 intersect at the bottom of the clamping end; the end of the elastic connecting rod 7 that intersects with the first elastic support foot 5 is fixed on the base 4, and the end of the elastic connecting rod 7 that intersects with the second elastic support foot 6 is connected to a sliding sleeve, and a sliding hole for avoiding the push rod 5 is provided on the sliding sleeve.

[0039] In this embodiment, the outer contour of the clamping end is arc-shaped, and a plurality of through holes are provided on the clamping end, and the plurality of through holes are arranged along the outer contour of the clamping end.

[0040] See Figures 1-6Because TPU material is a superelastic, a polymer compound composed of amorphous and long-chain molecules, its mechanical properties are between those of plastics and rubber, making it a non-linear material. Its elasticity differs from that of metals, exhibiting the characteristic of withstanding large elastic deformation while remaining almost incompressible. Due to its stable chemical and good physical properties, TPU material can quickly grasp and clamp objects of different shapes, especially soft, brittle, and surface-treated items, without damaging their surfaces. Therefore, in this embodiment, the multi-layered flexible claw 2 is formed using TPU material through an integrated injection molding process. In this embodiment, the multi-layered flexible claw 2 consists of two sets, positioned at 90 degrees. The elastic connector is the elastic connection portion 8 formed at the intersection of the first and second gripping claws in the multi-layered flexible claw 2 sets.

[0041] See Figures 1-9 In this embodiment, the multi-level flexible claw 2 adopts a multi-level single-cell configuration, wherein the multi-level single-cell configuration adopts an O-shaped configuration (e.g., Figure 9 (As shown); the multi-level flexible claw 2 is obtained by introducing a gradient lattice structure to optimize the overall topology of the mechanism and the distribution of unit cells with different stiffnesses within it, and can achieve gradient changes in stiffness within the design domain according to design requirements. The specific design method is as follows:

[0042] like Figure 7 As shown, the multi-level flexible claw 2 adopts a single-input, single-output model. The left end of the design domain is the input end, and the output displacement is located at the right boundary. The upper and lower parts of the design domain are fixed. Given the symmetry of this model, the lower half of the optimization region is used for design. Considering large geometrical nonlinear deformation within the design domain, a driving load (F) is applied from the input end. in The motion is transmitted through the elastic deformation of the mechanism, generating a virtual excitation displacement (U) perpendicular to the driving direction at the output end. out The elastic modulus of the clamping contact area is set to E. b A medium-density buffer layer is used to achieve soft contact between the fingertips and the fruit. The input and output spring stiffnesses are set to k respectively. in k out This is to simulate the stiffness of the input drive end and the fruit-clamping end. The lattice unit cell configuration adopts an O-shaped configuration, with a characteristic dimension x. i To define the width of the cavity wall thickness in the horizontal direction, a control model for the characteristic dimensions and the equivalent stiffness of the unit cell is established using a numerical homogenization method (e.g., Figure 8 As shown):

[0043]

[0044] In the formula, ε is the strain field, u is the strain generated macroscopically, and υ is the dynamic space U.ad Internal virtual displacement field, F t With F b These are the surface forces and body forces acting on the mechanism, Ω. MA For the macroscopic design domain, D(x) i ) is the elastic tensor of each unit.

[0045] Let the displacement at the output end of the mechanism be (U) out The ratio of the clamping area width (L) to the deformation rate at the output end is the value of the deformation rate at the clamping area width (L). With the goal of maximizing the deformation rate at the output end of the mechanism, the optimization formula is as follows:

[0046] find:x i (i = 1, 2, ..., N)

[0047]

[0048] st:G(x i )=∫ Ω MAV(x i )dΩ MA -V max ≤0

[0049] KU = F in

[0050] 0 < x min <x i ≤1

[0051] In the formula, x i Let x be the characteristic size of the mesoscopic unit, max be the function value maximization, and x be the characteristic size of the unit. min The characteristic size of the smallest mesoscopic element, N, is the total number of elements in the design domain, l out G(x) is a unit vector with a value of 1 at the output degree of freedom. i V represents the amount of material used within the design domain. max V(x) represents the upper limit of the total amount of materials used. i ) represents the material usage of the i-th element, K is the total stiffness matrix, and U is the design domain displacement.

[0052] The robot gripping device of the present invention adopts a spatially symmetrical structure with mutual perpendicularity in the form of a cross, which has the characteristics of compact structure, uniform force distribution, and wide applicability for grasping objects; in addition, the robot gripping device of the present invention only requires one driver to drive the push rod to apply force to 5 pairs of force application areas, which has the characteristics of simple spatial gripping operation; furthermore, the robot gripping device of the present invention is formed by TPU super elastic material through an integrated injection molding process, which has the characteristics of being lightweight, low cost, fast response and quick installation.

[0053] The above are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above content. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A robot flexible gripping device based on a multi-level flexible mechanism design, characterized in that, The system includes a base, multi-level flexible claws mounted on the base, and a clamping drive mechanism for driving the clamping openings of the multi-level flexible claws to perform clamping actions. The multi-level flexible claws are in multiple sets, and the multiple sets of multi-level flexible claws are arranged in a circle on the base; each set of multi-level flexible claws includes two symmetrically arranged clamping claws, which are a first clamping claw and a second clamping claw; wherein, the first clamping claw and the second clamping claw are connected by an elastic connector; the clamping claws are provided with clamping ends, and the clamping ends of the first clamping claw and the second clamping claw constitute the clamping opening of the multi-level flexible claw; The clamping drive mechanism is used to drive the elastic connector to move downward, so as to cause the clamping ends of the first clamping claw and the second clamping claw to rotate in opposite directions with the elastic connector as the rotation fulcrum, so as to realize the clamping action. The upper side of the clamping claw is the clamping end, and the lower side is the support part. The support part includes a first elastic leg, a second elastic leg, and an elastic connecting rod. The first elastic leg is located on the outer side, while the second elastic leg is located on the inner side. The two ends of the elastic connecting rod are respectively connected to the bottom of the first elastic leg and the second elastic leg, thus forming a triangular structure. The tops of the first elastic leg and the second elastic leg intersect at the bottom of the clamping end. The end of the elastic connecting rod that intersects with the first elastic leg is fixed to the base, and the end of the elastic connecting rod that intersects with the second elastic leg is connected to a sliding sleeve. The sliding sleeve is provided with a sliding hole to avoid the push rod. The multi-level flexible claw is a multi-level single-cell configuration structure, and the multi-level single-cell configuration structure adopts an O-shaped configuration. The multi-level flexible claw is obtained by introducing a gradient lattice structure to optimize the overall topology of the mechanism and the distribution of internal unit cells with different stiffnesses, and to achieve gradient changes in stiffness within the design domain according to design requirements.

2. The robot flexible gripping device based on a multi-level flexible mechanism design according to claim 1, characterized in that, A buffer layer is provided on the clamping end.

3. The robot flexible gripping device based on a multi-level flexible mechanism design according to claim 1, characterized in that, The clamping drive mechanism includes a linear motor and a push rod. The linear motor is mounted on a motor mounting base, and the main shaft of the linear motor is connected to the lower end of the push rod. The upper end of the push rod is connected to the elastic connector. The base is provided with a clearance hole for avoiding the push rod.

4. The robot flexible gripping device based on a multi-level flexible mechanism design according to claim 1, characterized in that, The outer contour of the clamping end is arc-shaped, and the clamping end is provided with a number of through holes arranged along the outer contour of the clamping end.

5. The robot flexible gripping device based on a multi-level flexible mechanism design according to claim 1, characterized in that, The multi-level flexible claw is formed using TPU material through an integrated injection molding process.

6. The robot flexible gripping device based on a multi-level flexible mechanism design according to claim 5, characterized in that, The multi-level flexible claw consists of two sets, which are set at 90 degrees. The two sets of multi-level flexible claws are formed using TPU material through an integrated injection molding process.

7. The robot flexible gripping device based on a multi-level flexible mechanism design according to claim 6, characterized in that, The elastic connector is an elastic connection formed at the intersection of the first and second gripping claws in a multi-level, multi-group flexible claw.

8. The robot flexible gripping device based on a multi-level flexible mechanism design according to claim 1, characterized in that, The ends of the elastic connecting rods in the first and second clamping claws of the multi-group, multi-level flexible claws intersect to form the sliding sleeve.

Images