A goal-shape adaptive general-purpose software gripper with bistable characteristics

Abstract

The application relates to a target shape adaptive general soft gripper with a bistable characteristic, which solves the technical problem of how to realize a simple soft gripper structure, convenient control, high response speed and better grabbing effect; the soft gripper body and the base are provided, the soft gripper body is provided with more than three flexible strips, the more than three flexible strips are radially distributed from the center point of the soft gripper body and uniformly distributed around the central axis, the flexible strips are provided with ends, the center line of the flexible strips is a logarithmic spiral, the base is provided with a mounting surface with an everted angle, the ends of the flexible strips are fixedly connected with the mounting surface with the everted angle, the ends of the more than three flexible strips are uniformly distributed around the central axis, and the flexible strips are arched outward. The application is widely applied to target grabbing operations in the fields of food industry, medical devices and aerospace.

Description

Technical Field

[0001] This invention relates to the field of soft gripper technology, and more specifically, to a target shape adaptive universal soft gripper with bistable characteristics. Background Technology

[0002] Soft grippers use flexible materials as their main structure and adapt to the shape of objects through flexible deformation to perform gripping, wrapping, and picking operations. Due to their high flexibility, adaptability, and safety, soft grippers have shown great application potential in fields such as the food industry, medical devices, and aerospace.

[0003] The existing soft gripper structures can be described in invention patent applications CN120620269A and CN118418166A. The main driving methods for soft grippers include pneumatic actuation, cable actuation, and smart material actuation. These driving structures are large in size and occupy a lot of space, and their complex control processes result in slow response speeds and poor target grasping effects. Therefore, developing a soft gripper with a simple structure, convenient control, high response speed, and better grasping effect has enormous potential value. Summary of the Invention

[0004] This application aims to solve the technical problem of how to achieve a soft gripper with simple structure, convenient control, high response speed, and better gripping effect, and provides a target shape adaptive general soft gripper with bistable characteristics.

[0005] In a first aspect, this application provides a target shape adaptive general-purpose soft gripper with bistable characteristics, including a soft gripper body and a base. The soft gripper body is provided with three or more flexible strips. The three or more flexible strips radiate outward from the center point of the soft gripper body and are evenly distributed around the central axis. The flexible strips are provided with ends, and the center line of the flexible strips is a logarithmic spiral, an involute, or an arc.

[0006] The base is provided with mounting surfaces with outward tilt angles. The number of mounting surfaces with outward tilt angles corresponds to the number of flexible strips. The ends of the flexible strips are fixedly connected to the mounting surfaces with outward tilt angles. The ends of three or more flexible strips are evenly distributed around the central axis, and the flexible strips arch outwards.

[0007] Preferably, the target shape adaptive general-purpose soft gripper with bistable characteristics further includes a drive mechanism for moving the center point of the soft gripper body toward the base.

[0008] Preferably, the driving mechanism includes a pull rope and a power source. One end of the pull rope is connected to the center point of the soft gripper body, and the other end of the pull rope passes through the center of the base and is connected to the power source. The power source can pull the pull rope towards the base.

[0009] Preferably, the power source includes a motor and a reel, the reel being connected to the output shaft of the motor, and the other end of the pull rope being wound around the reel.

[0010] Preferably, the power source includes a telescopic motor, and the other end of the pull rope is connected to the output end of the telescopic motor.

[0011] Preferably, the base is a rigid base.

[0012] Preferably, the width of the flexible strip gradually decreases from its end to the center point of the soft gripper body.

[0013] Preferably, the mounting surface with an outward tilt angle on the base is a mounting plate, and the mounting plate has an included angle α with the central axis, the included angle α being 0 to 30°; the inner side of the end of the flexible strip is fixedly connected to the outer side of the mounting plate.

[0014] A second aspect of this application provides a target grasping method using the aforementioned target shape adaptive general soft gripper with bistable characteristics, comprising the following steps:

[0015] Step P1: In steady state 1, each flexible strip arches outward.

[0016] In step P2, the dynamic target collides with the center point of the soft gripper body at a certain speed, causing each flexible strip to deflect inward, the center point to indent towards the base, and adjacent flexible strips to intersect. The soft gripper body jumps from steady state one to steady state two, at which point an envelope space is formed, which surrounds the target object.

[0017] A third aspect of this application provides a target grasping method using the aforementioned target shape adaptive general soft gripper with bistable characteristics, comprising the following steps:

[0018] Step S1: In steady state one, each flexible strip arches outward;

[0019] Step S2: The target object is placed at the center point of the soft gripper body;

[0020] Step S3: Next, the drive mechanism moves, causing the center point of the soft gripper body to move towards the base. As a result, each flexible strip deflects and folds inward, the center point is recessed towards the base, and adjacent flexible strips intersect. The soft gripper body jumps from steady state one to steady state two, at which point an envelope space is formed, which surrounds the target object.

[0021] The advantages of this application are its simple structure, high response speed, convenient control, and better grasping effect. It can grasp objects of different shapes with strong adaptability to target shapes. It can achieve fast and stable grasping of targets in different states, including static, quasi-static, and dynamic states.

[0022] It has enormous application potential in fields such as food industry, medical devices and aerospace.

[0023] Further features and aspects of this application will be clearly described in the following detailed description with reference to the accompanying drawings. Attached Figure Description

[0024] Figure 1 This is a three-dimensional structural diagram of the soft gripper body in a tiled state;

[0025] Figure 2 This is the front view of the soft gripper in steady state one (umbrella-shaped opening);

[0026] Figure 3 It is an isometric view of the soft gripper in steady state two (inward closure);

[0027] Figure 4 yes Figure 3 The diagram shows the structure of the software gripper grasping the target.

[0028] Figure 5 This is a schematic diagram of the software gripper installation and target acquisition process;

[0029] Figure 6 This is a schematic diagram showing the central axis formed by the center point of the gripper body pointing downwards. The red line in the diagram represents the central axis.

[0030] Figure 7 This is a schematic diagram of the connection structure between the mounting plate and the flexible strip on the base;

[0031] Figure 8 yes Figure 7 The diagram shows a structure in which the mounting plate and the central axis have an angle α.

[0032] Explanation of symbols in the diagram:

[0033] 1. Soft gripper body, 2. Base, 2-1. Mounting plate, 3. Pull rope, 11. Flexible strip, 12. Top, 13. End, 14. Center point, 15. Center line, 16. Angle. Detailed Implementation

[0034] The application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] The specific embodiments described below are merely preferred embodiments of this application, and the scope of protection of this application is not limited thereto. Those skilled in the art can make modifications or variations based on the principles, concepts, and spirit of this application, and the resulting technical solutions should all be covered within the scope of protection of this application.

[0036] like Figure 1 , Figure 2 As shown, the soft gripper includes a soft gripper body 1 and a base 2. The soft gripper body 1 consists of six flexible strips 11, which radiate outward from the center point. Each flexible strip 11 has a top end 12 and a bottom end 13. The top ends 12 of the six flexible strips 11 are connected together to form the center point, and the centerline extends downward from the center point to form the central axis (e.g., ...). Figure 6 As shown, six flexible strips 11 are evenly arranged around the central axis. The centerline 15 of each flexible strip 11 is a logarithmic spiral, which is beneficial for uniform stress distribution and reduces the critical force required for jump changes. The soft gripper body 1 is integrally molded from a flexible material (such as silicone rubber). The base 2 has mounting surfaces for fixing the ends 13. The mounting surfaces have a certain angle of outward tilt. The six mounting surfaces are evenly distributed around the central axis, and the ends 13 are fixedly connected to the mounting surfaces. The six ends 13 are evenly distributed around the central axis, as shown in the reference. Figure 2 and Figure 5 As shown in the upper right corner of the attached diagram, one mounting surface corresponds to one end 13, so that the flexible strip 11 arches outward in its natural state, providing geometric constraints for the bistable effect. The end 13 of each flexible strip 11 is fixedly connected to the mounting surface of the base 2, and the specific connection method can be a snap-fit ​​connection, adhesive bonding, or bolt connection.

[0037] The base 2 can be made of a rigid material.

[0038] For example, the mounting surface structure on base 2 is as follows Figure 7 and 8 As shown, a mounting plate 2-1 is provided on the base 2. The mounting plates 2-1 are arranged at an angle, and one mounting plate 2-1 corresponds to one flexible strip 11. The angle between the mounting plate 2-1 and the central axis is α, which is usually 0 to 30°. The inner side of the end 13 of the flexible strip 11 is fixedly connected to the outer side of the mounting plate 2-1.

[0039] Mounting plate 2-1 has a reasonable outward tilt angle to ensure the bistable stability of the soft gripper and improve the gripping force of the grasped object.

[0040] As shown in the attached figure, the width of the flexible strip 11 gradually decreases from its end 13 to its top 12 (that is, the width gradually decreases from its end 13 to the center point 14 of the soft gripper body 1), which is a better structural design. This is more conducive to the inward deflection of each flexible strip 11 to form an enveloping space.

[0041] A pull rope 3 is provided. One end of the pull rope 3 is connected to the center point of the soft gripper body 1, and the other end passes through the center of the base 2 and is connected to the drive mechanism. The drive mechanism can be a motor with a winding wheel. The other end of the pull rope 3 is wound on the winding wheel. The motor controls the winding and unwinding of the winding wheel by reversing forward and backward. The winding operation pulls the pull rope 3, and the unwinding operation releases the pull rope 3.

[0042] The specific working process of the aforementioned software gripper can be as follows:

[0043] The first case applies to static and quasi-static targets.

[0044] Step S1, in the initial state (i.e., steady state one), the soft gripper is in an umbrella-like open state, and the six flexible strips 11 arch outwards, as shown... Figure 2 As shown, the flexible strip 11 is forced to bend and stores elastic potential energy. The tension rope 3 is relaxed.

[0045] Step S2: Bring the entire soft gripper close to the target, and place the target at the center point 14 of the soft gripper body 1.

[0046] Step S3: Next, control the motor to rotate forward, the winding reel rotates to perform the winding operation, and the pull rope 3 pulls the soft gripper body 1, causing the center point 14 of the soft gripper body 1 to move towards the base 2. The target then moves towards the base 2 accordingly. Figure 5 As shown in the attached diagram in the lower right corner, as the rope 3 continues to tighten, when the center point 14 crosses a certain critical plane, the accumulated elastic potential energy of each flexible strip 11 is suddenly released. Each flexible strip 11 deflects inward, and the center point 14 of the soft gripper body 1 is recessed towards the base 2. Adjacent flexible strips 11 intersect, and the soft gripper body 1 instantly jumps from steady state one to steady state two (inward closure), as shown in the attached diagram in the lower right corner. Figure 3 As shown, an envelope space is formed at this point. The envelope space surrounds the target object, thus achieving the capture of the target object (e.g. Figure 4 (As shown).

[0047] In step S4, after grasping, the motor stops running, and the soft gripper body 1 maintains its closed position based on its own steady-state characteristics, achieving zero-energy-consumption gripping. At this time, even if the tension of the pull rope is removed, the soft gripper body 1 can still remain closed.

[0048] The motor can also continue to drive the pull rope 3 to retract a suitable distance, so that each flexible strip 11 continues to deflect, thereby reducing the envelope space and increasing the positive pressure on the target to further lock the target.

[0049] The second scenario applies to dynamic objectives.

[0050] Step P1, in the initial state (i.e., steady state one), the soft gripper is in an umbrella-like open state, with the six flexible strips 11 arching outwards, as shown... Figure 2 and Figure 5 As shown in the attached diagram in the upper right corner, the flexible strip 11 is forced to bend and stores elastic potential energy. The tension rope 3 is relaxed.

[0051] Step P2: The dynamic target collides with the center point 14 of the soft gripper body 1 at a certain speed, as shown in the reference. Figure 5 , Figure 5 The symbol 'v' indicates the moving speed of the dynamic target, propelling the center point 14 towards the base 2. When the impact causes the center point 14 to cross a critical plane, the accumulated elastic potential energy of each flexible strip 11 is suddenly released, causing each flexible strip 11 to deflect inwards. The center point 14 then indents towards the base 2, and adjacent flexible strips 11 intersect. The soft gripper body 1 instantly jumps from steady state one to steady state two (inward closure), as shown... Figure 3 and Figure 5 As shown in the attached diagram in the lower left corner, an envelope space is formed at this point, which enables the capture of the target object and the passive capture of the object without active driving.

[0052] In step P3, the drive mechanism can intervene to activate the motor and perform the winding operation, thereby reducing the envelope space formed by the flexible strip 11 and enhancing the locking force.

[0053] As can be seen, it can capture targets of different shapes and adapt to the target shape. It can achieve fast and stable capture of targets in different states, such as static, quasi-static, and dynamic. It has a simple structure, is easy to control, has a fast response speed, and is highly adaptable to target shapes. It has great application potential in the food industry, medical devices, and aerospace fields.

[0054] It should be noted that a logarithmic spiral is the preferred design for the center line of the flexible strip 11. In addition to a logarithmic spiral, the center line of the flexible strip 11 can also be an involute or a circular arc.

[0055] By selecting silicone rubbers of different hardness, the overall rigidity and gripping force of the gripper can be adjusted to meet the needs of grasping different target objects.

[0056] It should be noted that the number of flexible strips 11 is only an example of 6; the number of flexible strips 11 can also be three, four, five, seven, eight or more.

[0057] It should be noted that a telescopic motor can be used instead of a reel motor.

Claims

1. A target shape adaptive general-purpose soft gripper with bistable characteristics, characterized in that, The system includes a soft gripper body and a base. The soft gripper body has three or more flexible strips. The three or more flexible strips radiate outward from the center point of the soft gripper body and are evenly distributed around the central axis. The flexible strips have ends, and the center line of the flexible strips is a logarithmic spiral, an involute, or a circular arc. The base is provided with an outward tilting surface. The number of mounting surfaces with outward tilting angles corresponds to the number of flexible strips. The ends of the flexible strips are fixedly connected to the mounting surfaces with outward tilting angles. The ends of the three or more flexible strips are evenly distributed around the central axis, and the flexible strips arch outwards.

2. The target shape adaptive universal soft gripper with bistable characteristics according to claim 1, characterized in that, The target shape adaptive general-purpose soft gripper with bistable characteristics also includes a drive mechanism for moving the center point of the soft gripper body toward the base.

3. The target shape adaptive universal soft gripper with bistable characteristics according to claim 2, characterized in that, The drive mechanism includes a pull rope and a power source. One end of the pull rope is connected to the center point of the soft gripper body, and the other end of the pull rope passes through the center of the base and is connected to the power source. The power source can pull the pull rope towards the base.

4. The target shape adaptive universal soft gripper with bistable characteristics according to claim 3, characterized in that, The power source includes a motor and a winding reel, with the winding reel connected to the output shaft of the motor, and the other end of the pull rope wound around the winding reel.

5. The target shape adaptive universal soft gripper with bistable characteristics according to claim 3, characterized in that, The power source includes a telescopic motor, and the other end of the pull rope is connected to the output end of the telescopic motor.

6. The target shape adaptive universal soft gripper with bistable characteristics according to claim 1, characterized in that, The base is a rigid base.

7. The target shape adaptive universal soft gripper with bistable characteristics according to claim 1, characterized in that, The width of the flexible strip gradually decreases from its end to the center point of the soft gripper body.

8. The target shape adaptive universal soft gripper with bistable characteristics according to claim 1, characterized in that, The mounting surface with an outward tilt angle on the base is a mounting plate, and the mounting plate has an included angle α with the central axis, the included angle α being 0 to 30°; the inner side of the end of the flexible strip is fixedly connected to the outer side of the mounting plate.

9. A target grasping method using the target shape adaptive general soft gripper with bistable characteristics as described in claim 1, characterized in that, Includes the following steps: Step P1: In steady state one, each flexible strip arches outward. In step P2, the dynamic target collides with the center point of the soft gripper body at a certain speed, causing each flexible strip to deflect inward, the center point to indent towards the base, and adjacent flexible strips to intersect. The soft gripper body jumps from steady state one to steady state two, at which point an envelope space is formed, which surrounds the target object.

10. A target grasping method using the target shape adaptive general soft gripper with bistable characteristics as described in claim 2, characterized in that, Includes the following steps: Step S1: In steady state one, each flexible strip arches outward; Step S2: The target object is placed at the center point of the soft gripper body; Step S3: Next, the drive mechanism moves, causing the center point of the soft gripper body to move towards the base. As a result, each flexible strip deflects and folds inward, the center point is recessed towards the base, and adjacent flexible strips intersect. The soft gripper body jumps from steady state one to steady state two, at which point an envelope space is formed, which surrounds the target object.

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