Dual-drive soft gripper capable of reconstructing finger arrangement and grabbing space

Abstract

The invention discloses a dual-drive soft gripper capable of reconstructing finger arrangement and a gripping space. The device comprises a central palm module, the central palm module is provided with a reconfigurable configuration, the central palm module comprises at least one swing angle actuator, and the swing angle actuator is configured to change the relative angle of a finger base through controlled deformation to achieve switching of finger arrangement configurations; the at least one telescopic actuator is configured to drive the finger base to synchronously stretch out and draw back in the radial direction so as to adjust the effective length of the finger; the at least two soft finger modules are arranged in the circumferential direction of the central palm module, the rear end of each soft finger module is connected with the corresponding finger base, and the front end of each soft finger module is a free end. On the premise that the flexibility of the soft gripper body is kept and any electronic driving element is not needed, reconfigurable adjustment of the length, the arrangement mode, the rigidity and the overall working space of the fingers can be achieved at the same time.

Description

Technical Field

[0001] This invention relates to the field of robotic arm technology, specifically to a dual-drive soft gripper with reconfigurable finger arrangement and grasping space. Background Technology

[0002] As the application of robotics technology in unstructured environments continues to expand, end effectors need to achieve safe and stable grasping and handling in complex scenarios. Although traditional rigid manipulators can easily obtain high output force, their contact interface has high stiffness and insufficient compliance. When facing irregularly shaped, fragile, or easily damaged targets, they are prone to local stress concentration, which can lead to unstable gripping or damage to the target.

[0003] To address these issues, soft grippers, constructed from flexible materials, possess excellent adaptability and environmental resilience, and have been widely used in recent years in fields such as food sorting, agricultural harvesting, underwater operations, and biological sample processing.

[0004] Existing soft grippers typically use a single actuation method, such as pneumatic or hydraulic pressure, to cause the flexible cavity to bend and deform, thereby grasping the target object. Due to the relatively simple actuation method, the bending shape of the fingers, the output force, and the equivalent stiffness often change synchronously with the single actuation input, lacking the ability to independently control stiffness and bending shape. Consequently, it is difficult to achieve both compliant contact and reliable support in applications with varying loads or high stability requirements.

[0005] Furthermore, most existing soft grippers employ fixed finger arrangements and limited, unchangeable gripping space, which restricts their gripping modes and applicable object range. For small targets, the limited number of contact points and insufficient geometric closure conditions make stable gripping difficult. For large targets, the non-extendable finger length makes it difficult to cover different size ranges. For multiple particles or scattered targets, the discretely distributed fingers have large gaps in the closed state, making it easy for them to be missed or escaped during handling. As a result, it is difficult to use a single gripper to meet the needs of multiple tasks, such as gripping a wide range of objects across different scales and encapsulating multiple granular objects.

[0006] In summary, the shortcomings of existing technical solutions can be summarized as follows:

[0007] 1. The finger base and base position of the existing soft gripper are fixed after assembly, making it difficult to actively change the finger arrangement during the gripping process. This limits its ability to adapt to target objects of different shapes and sizes, and makes it difficult to switch the workspace according to the task.

[0008] 2. Existing soft grippers have fingers of fixed length and fixed segment structure, which can only rely on the same bending trajectory and effective stroke, resulting in a limited grasping range and difficulty in achieving both fine operation and large-area coverage on the same gripper.

[0009] 3. Existing soft grippers have discrete fingers that still have large gaps after closing, making it difficult to form a continuous closed boundary. When grasping a batch of particles or multiple small targets, they are prone to falling or escaping.

[0010] 4. Existing soft grippers achieve bending deformation through a single drive (mainly pneumatic or single rope drive), lacking independent control over bending shape and stiffness. This makes it difficult to improve support stiffness while maintaining compliant contact, thus limiting gripping stability and anti-interference capabilities.

[0011] 5. Existing soft grippers typically have a rectangular chamber structure, and bending usually occurs through deformation of the chamber wall, resulting in poor bending performance;

[0012] 6. Existing soft grippers are often manufactured by sewing fabric or molding silicone, which involves many processes, long manufacturing cycles and high costs, making it difficult to achieve rapid and low-cost mass production.

[0013] Therefore, there is an urgent need for a new type of soft gripper structure that can reconfigure and adjust finger length, arrangement, stiffness, and overall workspace while maintaining the compliant characteristics of the soft gripper body and without using any electronic drive components, so as to improve the versatility and functional integration of a single gripper in complex task environments. Summary of the Invention

[0014] To address the shortcomings of existing technologies, this invention provides a dual-drive soft gripper with reconfigurable finger arrangement and gripping space.

[0015] This invention includes:

[0016] The central hand module has an autonomously reconfigurable configuration, and the central hand module includes:

[0017] At least one sway actuator is configured to change the relative angle of the finger bases through controlled deformation, thereby switching the finger arrangement configuration; and

[0018] At least one telescopic actuator is configured to drive the finger base to extend and retract synchronously in the radial direction to adjust the effective length of the finger;

[0019] At least two soft finger modules are arranged circumferentially along the central palm module, with the rear end of each soft finger module connected to the corresponding finger base and the front end being a free end; each soft finger module includes:

[0020] The pneumatic bending unit has a preset crease constraint structure and is configured to generate controlled bending deformation along the crease constraint structure under air pressure.

[0021] A traction constraint unit includes a linear actuator and a flexible traction member, the flexible traction member being arranged along the length direction of the soft finger module, and the linear actuator being configured to apply traction constraint to the soft finger module through the flexible traction member; and

[0022] An envelope component is disposed on the back of the soft finger module and configured to overlap with the envelope component of the adjacent soft finger module when the soft finger module is bent and closed, forming a continuous or nearly continuous envelope boundary. This, combined with the reconfigurable mechanism, greatly enhances the range of the reconfigurable grasping space.

[0023] Among them, the pneumatic bending unit and the traction constraint unit can both drive the fingers to bend in the same or opposite directions. Their synergistic effect can enhance the gripping force or achieve a wide range of control over the gripping force, thereby improving the adaptability and gripping stability of objects of different weights and preventing over-gripping.

[0024] The switching of the finger arrangement configuration is coupled with the adjustment of the effective length of the fingers, forming a workspace that is adjustable in both shape and size.

[0025] The soft gripper can achieve a series of autonomous and reconfigurable adjustments such as finger arrangement, gripping space, and finger length without relying on any manual operation, motors, or gears, thereby simultaneously meeting the multi-functional operation requirements of cross-scale, multi-particle, and high-load applications.

[0026] as well as,

[0027] The autonomous reconfiguration and grasping control system is configured to perform the following operations:

[0028] It receives feedback information from the sensor system and controls the coordinated operation of the swing actuator, telescopic actuator, pneumatic bending unit and traction constraint unit to achieve autonomous reconfiguration and grasping control.

[0029] Among them, based on the recognition results of the target object's outline shape by the visual sensor, the swing angle actuator is controlled to select an appropriate finger arrangement configuration;

[0030] Based on the recognition result of the target object size, the telescopic actuator is controlled to adjust the finger to a suitable effective length;

[0031] During the grasping process, based on feedback from the sensors of the soft finger module, the dual-drive relationship between the pneumatic bending unit and the traction constraint unit is dynamically adjusted to optimize the grasping state.

[0032] In some embodiments, the oscillating actuator is a dual-cavity coupled origami actuator, having a central fixed part and fan-shaped origami chambers symmetrically arranged on both sides of the central fixed part. The fan-shaped origami chambers generate arc-shaped unfolding or contraction deformation under air pressure to drive the finger base to rotate around a preset axis.

[0033] In some embodiments, the telescopic actuator is a radial synchronous telescopic origami actuator, having a central fixed structure and multiple unidirectional telescopic origami structures evenly distributed along the circumference. Each of the unidirectional telescopic origami structures achieves axial telescopic displacement with equal amplitude and synchronization through a shared air passage.

[0034] In some embodiments, the central palm module further includes a limiting rotary guide rail and a positioning shaft. The limiting rotary guide rail is only allowed to rotate around a preset axis under the constraint of the positioning shaft. The finger base cooperates with the limiting rotary guide rail and moves radially under the drive of the telescopic actuator.

[0035] In some embodiments, the crease constraint structure is formed by folding a planar crease pattern, having a central trapezoidal surface and triangular surfaces symmetrically arranged on both sides of the central trapezoidal surface, and the pneumatic bending unit preferentially generates controlled collapse deformation along the crease under air pressure.

[0036] In some embodiments, the linear actuator is a unidirectional telescopic origami actuator, and the flexible traction member is a strip-shaped flexible traction belt. The strip-shaped flexible traction belt passes through the guide channel inside the soft finger module, with one end fixed to the front end of the soft finger module and the other end connected to the unidirectional telescopic origami actuator. When the pneumatic bending unit and the traction constraint unit drive the finger to bend in opposite directions, an antagonistic driving relationship can be formed. By adjusting the relative action of pneumatic drive and traction constraint, the bending shape and equivalent stiffness of the soft finger module can be synergistically controlled. When the finger is driven to bend in the same direction, the gripping force can be enhanced, improving the ability to cope with high-load, easily unstable gripping scenarios.

[0037] In some embodiments, the envelope member is a detachable envelope petal, the front end of the envelope petal has a sleeve-like structure that mates with the front end of the soft finger module, and the rear end has a plug-in structure that mates with the rear end of the soft finger module. The envelope petals of each soft finger module have different installation heights to avoid mutual interference during configuration switching.

[0038] In some embodiments, the soft finger module further includes:

[0039] A bending sensor, disposed on the back of the soft finger module, is used to detect bending deformation; and / or

[0040] A tactile sensor is disposed on the contact surface of the soft finger module to detect the contact state.

[0041] In some embodiments, the central palm module further includes a vision sensor configured to acquire three-dimensional spatial information, contour morphology information and pose information of the target object, providing feedback input for switching the finger arrangement configuration, adjusting the effective length of the fingers and regulating the antagonistic drive.

[0042] In some embodiments, the number of soft finger modules is four, which are evenly arranged around the circumference of the central palm module; the number of sway actuators is two, which are symmetrically arranged between adjacent soft finger modules, and the soft finger modules can be switched between parallel arrangement mode and diagonal arrangement mode through controlled deformation.

[0043] 1. Compared with the prior art, the present invention achieves the switching of finger arrangement between different configurations through the controlled bending of the dual-cavity coupled swing angle origami actuator at the central palm module, thereby changing the gripper's working space according to task requirements, improving the adaptability to targets of different shapes, postures and sizes, and can be used to perform twisting / rotating operations on targets.

[0044] 2. Compared with the prior art, the present invention uses a radial synchronous telescopic origami actuator to drive the effective length of each soft finger module to be synchronously adjustable. Combined with the finger arrangement reconstruction capability, the gripper can cover a larger grasping size range, enabling a single gripper to simultaneously meet multiple operation requirements such as fine clamping and large-area enveloping grasping.

[0045] 3. Compared with the prior art, the present invention couples and controls the finger arrangement reconstruction (θ) and radial synchronous extension (r) to form a workspace Ω(θ, r). The collaborative reconstruction in both shape and scale dimensions enables the gripper to achieve higher task coverage without increasing the number of fingers or introducing a rigid transmission mechanism.

[0046] 4. Compared with the prior art, the dual-drive soft finger module of the present invention adopts a pneumatic bending drive and a unidirectional telescopic origami actuator—a flexible traction belt—to form an adjustable antagonistic mechanism, which can maintain a compliant fit during the contact phase and increase the equivalent stiffness K during the load-bearing phase. eff This enables a continuous switching from compliant to supportive, thereby enhancing anti-slip, anti-disturbance, and load adaptability.

[0047] 5. Compared with the prior art, the present invention introduces a crease-constrained pneumatic bending unit into the pneumatic finger, which causes it to preferentially collapse / fold along a preset crease under pneumatic drive, thereby obtaining deformation characteristics with predictable bending trajectory, consistent bending direction and fast response, and achieving higher bending efficiency with smaller drive input.

[0048] 6. Compared with the prior art, the finger arrangement reconstruction, length adjustment and antagonistic driving process of the present invention are all achieved by pneumatic origami actuators of various configurations and geometric deformation and flexible traction of finger chamber bending. The entire gripper does not require manual disassembly and assembly or motors, servo motors or rigid transmission mechanisms during multi-configuration switching and stiffness adjustment, thereby reducing system complexity and improving structural safety and operational efficiency.

[0049] 7. Compared with the prior art, the detachable envelope petal assembly of the present invention forms a continuous or nearly continuous envelope boundary when the gripper is closed, reducing the drop and escape caused by the gap between the fingers, and improving the success rate of grasping particulate matter, multiple targets and easily slippery targets and the reliability of transportation.

[0050] 8. Compared with the prior art, the present invention introduces a depth camera, a tactile sensor and a bending sensor, which can acquire the target's three-dimensional information, contact state and structural deformation state, providing feedback support for configuration selection, drive allocation and stiffness adjustment, improving operational consistency and reducing reliance on human experience.

[0051] 9. Compared with the prior art, the present invention adopts a hard / soft material partition design and combines it with rapid prototyping processes such as 3D printing, which reduces the need for molds, assembly and external rigid transmission mechanisms, shortens the manufacturing cycle and reduces costs, while improving structural consistency and maintainability, which is conducive to promotion and application. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the structure of a dual-drive soft gripper with reconfigurable finger arrangement and gripping space;

[0053] Figure 2 This is an exploded view of a dual-drive software gripper with reconfigurable finger arrangement and gripping space;

[0054] Figure 3 This is a cross-sectional view of a dual-cavity coupled swing-angle paper folding actuator;

[0055] Figure 4 This is a schematic diagram of the reconfigurable finger arrangement principle;

[0056] Figure 5 This is a diagram illustrating the finger extension and retraction pattern;

[0057] Figure 6 This is a schematic diagram of the finger extension / retraction mechanism;

[0058] Figure 7 This is an exploded view of the software finger module;

[0059] Figure 8 This is a flowchart of the evolution of a crease-constrained aerodynamic bending unit;

[0060] Figure 9This is a schematic diagram of the dual-drive and antagonistic mechanism of the fingers;

[0061] Figure 10 This is a diagram illustrating how a grabber handles a package.

[0062] Figure 11 It is a flowchart of autonomous reconfigurability and capture control. Detailed Implementation

[0063] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0064] This application proposes a dual-drive soft gripper with reconfigurable finger arrangement and grasping space. The gripper is entirely gas-driven and mainly includes a reconfigurable central palm module 1 and four dual-drive soft finger modules 2 evenly arranged circumferentially along the central palm module. The rear end of each soft finger module is connected to the central palm module, and the other end is a free end for contacting the target object. Figure 1 As shown, the entire software gripper simultaneously satisfies four major characteristics: reconfigurable finger arrangement and gripping space, adjustable finger length, dual-drive antagonistic mechanism, and wrap-around gripping.

[0065] In one embodiment, such as Figure 2 As shown, the central hand module includes an upper round cover 11, a lower round cover 12, a depth camera 13, a dual-cavity coupled angular origami actuator 14, a radial synchronous telescopic origami actuator 15, a positioning shaft 16, a limiting rotary guide rail 17, and a finger base 18, which can realize the reconfigurable arrangement of fingers during the grasping process, thereby changing the working space of the gripper.

[0066] Furthermore, the upper round cover, lower round cover, positioning shaft, limiting rotary guide rail, and finger base are made of rigid materials (such as PLA, PETG, etc.) through 3D printing; the radial synchronous telescopic origami actuator and the dual-cavity coupled swing angle origami actuator are made of flexible materials (such as TPE, TPU, etc.) through 3D printing in one piece.

[0067] The positioning shaft fixes the limiting rotary guide rail to the upper circular cover, allowing the limiting rotary guide rail to rotate only clockwise and counterclockwise around the positioning shaft. The finger base is connected to the limiting rotary guide rail, and under the drive of the radial synchronous telescopic origami actuator and the guidance of the limiting rotary guide rail, the finger base performs controllable telescopic movements.

[0068] The radial synchronous telescopic origami actuator has its central base fixed on the upper round cover. The central air path of the central base is synchronously connected to and drives four unidirectional telescopic origami structure chambers with identical structures in the upper, lower, left, and right directions. When positive pressure is input, the four origami structures unfold simultaneously, and when negative pressure is input, the origami structures contract simultaneously. The telescopic path is a straight line.

[0069] Furthermore, such as Figure 6 As shown, the radially synchronous telescopic origami has a free end face 152. Four completely identical unidirectional telescopic origami structures are connected to the central fixed structure 151 through a 3D printing integrated molding method. Under the action of air pressure, each telescopic end generates radial displacement with the same direction and amplitude under the geometric constraints of origami. Structurally, this ensures that each dual-drive soft finger module connected to it obtains equal-amplitude and synchronous telescopic movement, avoiding the inconsistent phenomenon of a single finger moving ahead or behind.

[0070] Furthermore, there are two dual-cavity coupled folding actuators, symmetrically installed between two adjacent fingers. The middle, unfolded portion of the actuator is fixed between the upper and lower end caps, and connects to the two fan-shaped folding cavities. Under positive pressure, the two chambers continuously expand in an arc shape; under negative pressure, they contract until the folding surfaces adhere to each other in a rectangular shape. The contraction and expansion paths form an arc. Figure 3 .

[0071] During the reconstruction of finger arrangement, the limiting rotary guide rail is only allowed to rotate around a preset axis under the limiting action of the positioning shaft, and its rotation angle corresponds one-to-one with the unfolding or collapsing deformation amplitude of the dual-cavity coupled swing angle origami actuator, thus ensuring the repeatability and stability of the configuration switching process from a structural perspective.

[0072] Furthermore, the depth camera is installed in the central groove of the lower round cover for visual recognition of target objects. The depth camera is used to collect three-dimensional spatial distance information, contour morphology information and pose information between the target object and the gripper. Its output data is used to characterize the size, shape distribution and relative position of the target object.

[0073] The central hand module in this embodiment has the function of reconfiguring finger arrangement and workspace, as well as extending and retracting finger length. A dual-cavity coupled angular origami actuator is used, which drives the limiting rotary guide rail connected to the fingers to rotate via pneumatic input, thereby changing the finger arrangement and grasping space. For example... Figure 4 As shown, the grippers can be divided into parallel arrangement mode and diagonal arrangement mode, which allows the grippers to switch the gripping mode autonomously according to the geometry of the target object to achieve more stable and efficient gripping.

[0074] Unlike existing technologies where the base of the fingers is fixed to a rigid, non-deformable base or requires manual disassembly and motor drive to change the finger arrangement, this embodiment uses a dual-cavity coupled folding actuator built into the central palm module. By leveraging air pressure regulation and the autonomous structural deformation of the folding actuator, the relative position and arrangement of the soft finger modules can be dynamically adjusted, thus reconstructing the grasping mode and workspace.

[0075] In this embodiment, the central palm module of the soft gripper has a radially synchronous telescopic origami actuator that passes through a limiting rotary guide rail and a fixed base, connecting to the rear end of the fingers. When the origami is compressed under negative pressure, the fingers shorten; when it is extended under positive pressure, the fingers lengthen. Figure 4 , Figure 5 and Figure 6 As shown. By controlling this structure, the soft finger module can switch between different length states, thereby expanding the graspable size range of the gripper. The limiting rotary guide rail and the fixed base play a guiding role, ensuring the stability of the finger's extension and retraction direction.

[0076] Unlike existing technologies that use motors to drive linkages or gears to extend or shorten fingers, this embodiment uses radial synchronous telescopic origami to achieve finger extension and retraction. It requires no electronic components or rigid parts, making it more convenient, safe, and low-cost, and also enabling stable and adjustable grasping range.

[0077] In one embodiment, such as Figure 7 As shown, the dual-drive soft finger module 2 includes a unidirectional telescopic origami actuator 21, a flexible traction belt 22, a tactile sensor 23, a pneumatic finger 24, a bending sensor 25, and a detachable envelope flap assembly 26.

[0078] The dual-drive soft finger module in this embodiment has four detachable envelope petal assemblies, forming a continuous envelope or near-closed grasping space to improve the reliability of multi-target grasping and achieve enveloping grasping. The soft finger module uses origami traction drive and gas drive to achieve bending, realizing dual drive and variable stiffness based on antagonistic mechanism, and cooperates with each other in structure and function to achieve adjustable and reconfigurable grasper workspace, finger arrangement, length and equivalent stiffness.

[0079] Furthermore, the detachable envelope petal assembly, pneumatic fingers, and unidirectional telescopic origami actuator are made of soft materials (such as TPE and TPU) through 3D printing.

[0080] Furthermore, the hollow sleeve-like structure at the front end of the detachable envelope petal assembly is connected to the fingertip, and the dovetail tenon at the rear end is connected to the dovetail groove 242 at the rear end of the finger, which is used to eliminate the huge gap between the fingers.

[0081] Furthermore, the detachable envelope petal assembly also has four trapezoidal grooves that correspond one-to-one with the four origami chamber joints of the pneumatic finger, giving it crease-guiding properties and reducing the impact on finger bending performance. The four petals are installed at different heights in the finger, that is, the sleeve structure 261 and dovetail tenon 262 in the four petals are at different heights, in order to prevent the petals from interfering with each other during the reconstruction of the finger arrangement by the gripper.

[0082] Furthermore, the pneumatic finger has four chambers, and the surface of each chamber has crease-constrained pneumatic bending units 244. When the finger bends, it can bend accurately along the creases of the crease-constrained pneumatic bending units, and the origami structure has a certain rigidity to enhance the support of the finger. The planar pattern of the crease-constrained pneumatic bending unit is folded along the dotted lines to form a three-dimensional structure with five surfaces, of which the central surface is trapezoidal and the other four surfaces are triangular. When the two outermost surfaces are parallel and perpendicular to the ground, half of the origami structure is formed. Following the principle of symmetry, the complete crease-constrained pneumatic bending unit can be obtained by mirroring along the rightmost edge (see...). Figure 8 Driven by air pressure, the fingers preferentially undergo controlled collapse deformation along preset creases, ensuring that the bending trajectory is predictable and consistent in direction.

[0083] Furthermore, the flexible traction belt is preferably a flexible element with equivalent function, such as a ribbon or a flexible strip. The unidirectional telescopic origami actuator changes the telescopic length through air pressure, with positive pressure extending and negative pressure contracting, thereby driving the traction component to bend and deform the fingers.

[0084] The flexible traction belt passes through the rectangular hollow structure 245 of the pneumatic finger, with one end fixed to the fingertip and the other end connected to the one-way telescopic origami actuator. When the one-way telescopic origami actuator contracts and acts on the traction component, the traction component pulls on the pneumatic finger, thereby changing the degree of bending of the finger or inhibiting its further bending.

[0085] Furthermore, the bending sensor is installed on the back of the pneumatic finger, sandwiched between the pneumatic finger and the envelope flap assembly. It can be of the resistive or flexible strain type, and outputs an electrical signal related to the bending angle or curvature to accurately reflect the finger deformation state. The tactile sensor is embedded in the flexible material or attached to the contact surface. It can be of the piezoresistive or capacitive flexible sensing structure, and outputs an electrical signal related to the contact force or contact area to sense the contact state of the target object.

[0086] To achieve independent control over the bending shape and equivalent stiffness, this embodiment introduces a flexible traction belt driven by a unidirectional telescopic origami actuator into the pneumatic finger. Positive pressure drive is used to achieve downward bending of the finger, while negative pressure drive and traction drive are used to achieve upward bending of the finger, thus creating an antagonistic relationship between gas drive and traction drive in the soft finger module. Figure 9 As shown, when positive pressure drive and traction drive work simultaneously, the deformation of the inner wall of the pneumatic cavity and the strip-shaped traction component form a mutual constraint, causing the equivalent deformation stiffness of the soft finger module under external force to change with the relative magnitude of the two drive inputs. This stiffness adjustment originates from the passive response generated by structural coupling, requiring no additional rigid components or independent stiffness adjustment mechanisms. When negative pressure drive and traction drive work simultaneously, they drive the finger to bend in the same direction, significantly improving the gripping force and meeting the requirements of high-load and easily unstable gripping conditions. In the undriven state, the finger recovers its original shape based on the resilience of the soft material and the initial structural stiffness. By adjusting the relative magnitude of the two drives, compliant contact or high-stiffness support can be achieved in different gripping stages, thereby improving gripping stability and anti-interference ability.

[0087] In a dual-drive antagonistic finger, pneumatic drive generates a bending drive torque M. b (P b The unidirectional telescopic origami actuator generates a traction force T(P) via a flexible traction belt. t And apply a reverse constraint torque M. t (T). Under the small deformation approximation, the curvature change Δκ caused by the external load disturbance ΔF satisfies Δκ≈ΔM / K. eff The equivalent bending stiffness can be expressed as K. eff (P b ,P t )=K0+αP b +βT(P t Where K0 is the reference stiffness derived from the material and crease geometry, and α and β represent the contribution coefficients of aerodynamic pressure and traction constraint to the equivalent stiffness, respectively. By adjusting P b With P t The relative size of the components allows for continuous adjustment of the equivalent stiffness while maintaining the bending shape.

[0088] Based on the aforementioned antagonistic regulation mechanism, the grasping process can achieve performance switching in stages: the contact stage uses aerodynamic compliance to increase the contact area and reduce the risk of damage to fragile targets; the load-bearing stage uses traction constraints to suppress excessive bending and improve K. eff This achieves a performance leap between "compliance and support" within the same structure, avoiding the contradiction between compliance and load-bearing capacity in traditional solutions, forming a "1+1>2" gain in gripping stability, and improving the ability to resist disturbances.

[0089] Compared with existing solutions that use ropes and springs to form antagonism, the flexible traction component in this embodiment is preferably a strip-shaped flexible traction belt, which forms a surface contact constraint with the fingers. Compared with ropes that form line contact, it is easier to achieve uniform force and repeatable constraint boundaries. Moreover, the pneumatic origami chamber can be adjusted in real time, avoiding the problems of constant spring force and insufficient adjustment flexibility.

[0090] The traction constraint unit in this embodiment abandons the traditional "tendon rope / cable + winding" driving method. The pneumatic unidirectional telescopic origami actuator directly outputs linear displacement, and the constraint is applied along the crease guide path by the flexible traction belt. There is no need for winding transmission structures such as motors and servo motors, which greatly reduces the risk of failure caused by winding, friction and local stress concentration, and improves transmission efficiency and working safety.

[0091] In this embodiment, the radial synchronous telescopic origami actuator is used to drive the radial synchronous telescopic extension and retraction of the soft finger module; the dual-cavity coupled swing angle origami actuator is used to drive the switching of the finger arrangement configuration; the unidirectional telescopic origami actuator, in conjunction with the flexible traction belt, applies traction constraint to the finger; the crease constraint pneumatic bending unit is used to limit the finger to bend preferentially along the preset crease; and the detachable envelope petal assembly is used to form a continuous or nearly continuous envelope boundary.

[0092] The gripper configuration in this embodiment can be characterized by a set of parameters: the relative angle θ of the finger base (driven by a dual-cavity coupled oscillating origami actuator) and the radial extension r (driven by a radial synchronous extension origami actuator) together determine the spatial distribution of the finger endpoint set, and thus determine the shape and scale of the reachable workspace Ω(θ, r) of the gripper.

[0093] Furthermore, the finger arrangement reconstruction and radial synchronous expansion are not simply superimposed: the arrangement angle θ mainly defines the geometric boundary shape of the grasping space, while the radial expansion amount r mainly adjusts the boundary scale of the grasping space. The two are coupled to form a reconfigurable topology of the grasping space boundary, allowing the grasping space to be adjusted simultaneously in both the "shape" and "scale" dimensions. This enables a single gripper to handle multiple tasks such as fine gripping, cross-scale envelope, and multi-target processing without changing the number of fingers or introducing rigid transmission, thus achieving spatial reconstruction gains.

[0094] The assembly process of this application embodiment:

[0095] The four evenly distributed circular holes of the upper circular cover 11 pass through the four cylinders of the lower circular cover 12 to form an interference fit; the depth camera 13 is installed in the center of the lower circular cover to facilitate object recognition; the middle non-folded part of the two dual-cavity coupled folding actuators 14 is symmetrically fixed between the upper and lower end covers, and the two end faces of their folding parts are respectively connected to the sides of the two limiting rotary guides 17. When the folding is bent and deformed, it drives the limiting rotary guides to rotate, thereby changing the finger arrangement configuration to adapt to different shaped target objects.

[0096] The positioning shaft 16 passes through the round hole of the limiting rotary guide rail 17 and is fixed to the lower end cover 12. The two are in clearance fit, which is used to limit the rotation of the limiting rotary guide rail to rotate only in the direction of the positioning shaft. The rectangular outer surface of the finger base 18 is connected to the inner surface of the limiting rotary guide rail 17 to form a clearance fit. The end of the finger base away from the limiting rotary guide rail is connected to the pneumatic finger 24 and its position is fixed through the positioning hole 243.

[0097] The central fixing structure 151 of the radial synchronous telescopic origami actuator 15 is fixed on the upper round cover. The origami end face 152 of its origami part passes through the limiting rotary guide rail and the finger base in sequence and is connected to the rear end face 246 of the pneumatic finger. The radial synchronous telescopic origami actuator consists of four unidirectional telescopic origami structures with the same structure and a central fixing structure. Air pressure enters from the air passage of the central fixing structure and is evenly distributed to each origami chamber, so that the four origami chambers produce radial telescopic displacement with the same amplitude when they extend and retract, thereby realizing the synchronous telescopic adjustment of multiple fingers to match target objects of different sizes.

[0098] One end of the unidirectional telescopic origami actuator 21 is fixedly connected to the finger base, and the other end is connected to the flexible traction belt 22. The flexible traction belt passes through multiple hollow rectangular structures 245 of the pneumatic finger, and after the flexible traction belt’s limiting structure 221 forms a contact limit with the first hollow rectangular structure at the top of the fin-shaped fingertip 241 of the pneumatic finger, it completes the connection with the pneumatic finger. When the unidirectional telescopic origami actuator retracts, it pulls the flexible traction belt, which in turn drives the pneumatic finger to bend and deform.

[0099] The tactile sensor 23 is fixed to the upper surface of the chamber segment and the fin-like fingertip of the pneumatic finger; the bending sensor 25 is fixed to the back of the pneumatic finger and sandwiched between the detachable envelope flap assembly 26 and the pneumatic finger.

[0100] The assembly process of the detachable envelope petal assembly involves first engaging its front sleeve structure 261 with the fin-shaped fingertip 241 of the pneumatic finger (i.e., inserting the fin-shaped fingertip into the front sleeve structure), and then engaging the rear dovetail tenon 262 of the detachable envelope petal assembly with the rear dovetail groove 242 of the pneumatic finger (i.e., inserting the dovetail groove into the dovetail tenon), thereby achieving quick and detachable assembly of the envelope petal assembly.

[0101] In this embodiment, the rigid parts (upper / lower round covers, limiting rotary guide rails, finger bases, etc.) can be made of ABS, nylon, PC, POM, fiber-reinforced composite materials or metal materials, except for PLA and PETG; the flexible parts (origami parts, soft fingers, etc.) can be made of silicone, SEBS or a multi-material gradient combination, except for TPE / TPU.

[0102] In addition to conventional FDM 3D printing, this embodiment can employ processes such as injection molding, silicone casting / molding, SLA / DLP photopolymerization printing, and wire cutting to meet the requirements of mass production, precision, or cost.

[0103] like Figure 11 As shown in the embodiment of this application, the autonomous reconfiguration and grasping control process of the dual-drive software gripper is also provided:

[0104] First, the vision sensor captures an image of the object and identifies its shape. By analyzing the object's appearance features, it determines whether its cross-section is rectangular, circular, or square, and then feeds the recognition results back to the computer. The computer then decides on the arrangement of the grippers based on the object's cross-sectional shape to match its geometric features. If the object is approximately rectangular, a parallel finger arrangement is used; if it is approximately circular or square, a diagonal finger arrangement is used. Subsequently, the computer feeds the decision back to the control system, which then manipulates the angular actuator in the gripper's central hand module to adjust the gripper arrangement, ensuring proper contact with the object.

[0105] After determining the finger arrangement, the vision sensor further detects the object's length, width, height, and other dimensional information in real time and feeds it back to the computer. The computer compares the object's size with the current gripper configuration. If the object is larger, it controls the fingers to extend; if it is smaller, it controls the fingers to retract. The computer then sends the command back to the control system, which controls the telescopic actuator in the gripper's central palm module to adjust the finger length, ensuring that the gripping range matches the object's size. After the length adjustment is complete, the gripper is moved to the corresponding position on the target object to perform the gripping action.

[0106] After the gripper contacts the target object, multiple sensors provide real-time feedback to dynamically fine-tune the gripping force, bending angle, and stiffness of the gripper, ensuring gripping stability. The bending sensor monitors the deformation of the gripper, focusing on detecting excessive bending. If abnormal bending or unstable gripping occurs, the bending sensor sends a signal to the control system. The control system detects the gripper deformation based on this information and dynamically compensates for the bending angle. The tactile sensor monitors the gripping pressure and contact point distribution, providing feedback on the object's contact state and shape changes, and adjusting the gripping force in real time to avoid over-gripping and object slippage.

[0107] Ultimately, the control system integrates real-time information from vision, bending, and tactile sensors to dynamically adjust parameters such as the optimal arrangement of the grippers, extension length, gripping force, and bending angle, ensuring stable and precise gripping. This closed-loop control system allows the grippers to always maintain the most suitable state for gripping the current object, effectively avoiding gripping failures or instability.

[0108] Example: Package Grabbing

[0109] To improve the reliability of grasping particulate matter or multiple targets, this embodiment features a detachable envelope petal assembly on the back of the pneumatic finger. The detachable envelope petal assembly is 3D printed from a flexible material (such as TPE or TPU) and can be integrally formed with the pneumatic finger or detachably connected to it via a front sleeve structure and a rear dovetail connection structure. Preferably, the four detachable envelope petal assemblies are installed at staggered heights to prevent interference during finger reconfiguration.

[0110] Unlike existing soft grippers with discrete finger distribution and large inter-finger openings when closed, the detachable enveloping petal assembly in this embodiment, inspired by the biomimetic mechanism of flower petals protecting the stamen, allows it to converge as the fingers bend. The four petal assemblies overlap or interlock to form a continuous or near-continuous enveloping boundary, effectively reducing the perimeter and area of ​​the grasping space opening, thus minimizing or eliminating inter-finger gaps. When fully closed, it forms a nearly enclosed enveloping space, structurally suppressing particle leakage and multi-target escape, allowing the gripper to maintain stable envelopment and transport even with relatively low clamping force. Figure 10 As shown; when it is not necessary to wrap and grasp a batch of objects, the petal assembly can be disassembled at any time without affecting the fine clamping operation.

[0111] Detachable envelope flap assembly and configuration switching coordination: Under different finger arrangement configurations such as parallel / diagonal, the staggered installation height avoids interference between flap assemblies and maintains the continuity of the closed boundary, allowing the gripper to quickly switch between open gripping and envelope grasping, realizing multi-mode reuse of the same gripper and improving batch grasping efficiency.

[0112] In summary, the central palm module of this application is equipped with a radial synchronous telescopic origami actuator and a dual-cavity coupled swing angle origami actuator. After being driven, it produces controlled folding and bending deformation to change the position, angle or relative spacing of the finger base, thereby realizing the reconfigurability of finger arrangement, length and gripper working space.

[0113] The pneumatic finger of this application is equipped with a crease-constrained pneumatic bending unit that can collapse / fold a flexible cavity or origami joint under the action of driving, so as to achieve rapid and reversible bending for compliant gripping and rapid response.

[0114] This application features a one-way telescopic origami actuator on a pneumatic finger—a flexible traction belt forming a traction constraint chain. The traction constraint drive is a linear displacement and acts along the crease guide path, which is different from the existing technology that commonly uses a motor-driven rope winding or a spring constant force antagonistic structure.

[0115] The pneumatic drive and traction constraint drive of this application form an antagonistic relationship on the same finger, which can adjust the bending shape and equivalent stiffness, and improve the anti-slip and anti-interference capabilities. Furthermore, the dual-drive antagonistic mechanism of the dual-cavity coupled angular origami actuator, the radial synchronous telescopic origami actuator and the soft finger module work together to ensure that the gripper can maintain a compliant fit during the contact phase under different angular arrangement configurations and different grasping space scales, and provide enhanced structural stability during the load-bearing or transfer phase.

[0116] The pneumatic finger of this application is equipped with a detachable envelope flap assembly (which can be integrally molded or detachable) on the back, which forms a continuous / nearly continuous envelope boundary when closed, improving the reliability of grasping particulate matter, multiple targets and easily escaped living targets.

[0117] The finger base of this application cooperates with the limiting rotary guide rail and the positioning shaft to allow the finger base to move or switch positions within a limited trajectory, ensuring repeatable positioning and structural stability during the arrangement and reconstruction process.

[0118] The upper / lower round cover, slide rail, base, etc. of this application are made of rigid materials, while each origami component, pneumatic finger and petal assembly are made of flexible materials. All of them can be formed by 3D printing to achieve structural integration, reduce assembly complexity and cost, and facilitate mass production.

[0119] The depth camera in this application is installed in the central groove of the lower round cover and faces the grasping space to collect the three-dimensional information of the target, providing perceptual input for configuration selection, layout reconstruction and drive allocation;

[0120] This application arranges a tactile sensor on the surface of an object in contact with a pneumatic finger, and a bending sensor between the back of the pneumatic finger and the flap assembly. Combined with a control unit, it realizes contact / deformation feedback for closed-loop adjustment of gripping force, stiffness, or configuration.

[0121] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A dual-drive soft gripper with reconfigurable finger arrangement and grasping space, characterized in that, include; A central palm module, having a reconfigurable configuration, includes: At least one sway actuator is configured to change the relative angle of the finger bases through controlled deformation, thereby switching the finger arrangement configuration; and At least one telescopic actuator is configured to drive the finger base to extend and retract synchronously in the radial direction to adjust the effective length of the finger; At least two soft finger modules are arranged circumferentially along the central palm module, with the rear end of each soft finger module connected to the corresponding finger base and the front end being a free end; each soft finger module includes: The pneumatic bending unit has a preset crease constraint structure and is configured to generate controlled bending deformation along the crease constraint structure under air pressure. A traction constraint unit includes a linear actuator and a flexible traction member, the flexible traction member being arranged along the length direction of the soft finger module, and the linear actuator being configured to apply traction constraint to the soft finger module through the flexible traction member; and An envelope member is disposed on the back side of the soft finger module and configured to overlap with the envelope members of adjacent soft finger modules when the soft finger module is bent and closed, forming a continuous or nearly continuous envelope boundary. The pneumatic bending unit and the traction constraint unit form an antagonistic driving relationship. By adjusting the relative action of pneumatic driving and traction constraint, the bending shape and equivalent stiffness of the soft finger module can be coordinated and controlled. The switching of the finger arrangement configuration is coupled with the adjustment of the effective length of the fingers, forming a workspace that is adjustable in both shape and size.

2. The dual-drive soft gripper according to claim 1, characterized in that, The swing actuator is a dual-cavity coupled origami actuator, which has a central fixed part and fan-shaped origami chambers symmetrically arranged on both sides of the central fixed part. The fan-shaped origami chambers generate arc-shaped unfolding or contraction deformation under air pressure to drive the finger base to rotate around a preset axis.

3. The dual-drive soft gripper according to claim 1 or 2, characterized in that, The telescopic actuator is a radial synchronous telescopic origami actuator, which has a central fixed structure and multiple unidirectional telescopic origami structures evenly distributed along the circumference. Each of the unidirectional telescopic origami structures achieves equal-amplitude synchronous axial telescopic displacement through a shared air passage.

4. The dual-drive soft gripper according to claim 3, characterized in that, The central palm module also includes a limiting rotary guide rail and a positioning shaft. The limiting rotary guide rail is only allowed to rotate around a preset axis under the constraint of the positioning shaft. The finger base cooperates with the limiting rotary guide rail and moves radially under the drive of the telescopic actuator.

5. The dual-drive soft gripper according to claim 1, characterized in that, The crease constraint structure is formed by folding a planar crease pattern, and has a central trapezoidal surface and triangular surfaces symmetrically arranged on both sides of the central trapezoidal surface. The pneumatic bending unit preferentially generates controlled collapse deformation along the crease under air pressure.

6. The dual-drive soft gripper according to claim 1 or 5, characterized in that, The linear actuator is a one-way telescopic origami actuator, and the flexible traction component is a strip-shaped flexible traction belt. The strip-shaped flexible traction belt passes through the guide channel inside the soft finger module, with one end fixed to the front end of the soft finger module and the other end connected to the one-way telescopic origami actuator.

7. The dual-drive soft gripper according to claim 1 or 5, characterized in that, The envelope component is a detachable envelope petal. The front end of the envelope petal has a sleeve-like structure that mates with the front end of the soft finger module, and the rear end has a plug-in structure that mates with the rear end of the soft finger module. The envelope petals of each soft finger module have different installation heights to avoid mutual interference during configuration switching.

8. The dual-drive soft gripper according to claim 7, characterized in that, The soft finger module also includes: A bending sensor, disposed on the back of the soft finger module, is used to detect bending deformation; and / or A tactile sensor is disposed on the contact surface of the soft finger module to detect the contact state.

9. The dual-drive soft gripper according to claim 1, characterized in that, The central palm module also includes a vision sensor, which is configured to collect three-dimensional spatial information, contour morphology information and pose information of the target object, and provide feedback input for switching the finger arrangement configuration, adjusting the effective length of the fingers and regulating the antagonistic drive.

10. The dual-drive soft gripper according to claim 1 or 9, characterized in that, The number of soft finger modules is four, which are evenly arranged around the circumference of the central palm module; the number of swing angle actuators is two, which are symmetrically arranged between adjacent soft finger modules, and the soft finger modules can switch between parallel arrangement mode and diagonal arrangement mode through controlled deformation.

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