A reconfigurable manipulator

Abstract

The present application provides a reconfigurable manipulator, which relates to the field of robotics, and includes: a servo drive module and a pneumatic drive module connected to the servo drive module, and an under-actuated finger arranged on the pneumatic drive module, wherein the under-actuated finger and the pneumatic drive module are rotationally connected; the under-actuated finger at least includes a proximal finger end rotary joint, a finger middle phalanx, a distal finger end rotary joint, and a finger end phalanx connected in sequence, and the pneumatic drive module is connected to the proximal finger end rotary joint; the proximal finger end rotary joint and the distal finger end rotary joint are respectively connected to the pneumatic drive module, and the pneumatic drive module provides positive air pressure to adjust the rotational stiffness of the proximal finger end rotary joint and the distal finger end rotary joint in any direction. Adjusting the rotational stiffness of the distal finger end rotary joint and the proximal finger end rotary joint can achieve under-actuated grasping or decoupling to individually control the position of each rotary joint. The under-actuated adaptive capability and full-drive maneuverability can cope with a variety of general service scenario tasks.

Description

Technical Field

[0001] The present application relates to the field of robotics technology, and in particular to a reconfigurable manipulator. Background Art

[0002] As robotic applications expand into service and domestic settings, designing dexterous manipulators that achieve the maneuverability and compactness of human hands has become a major challenge in robotics. General robotic applications require not only that dexterous manipulators adapt well to unknown object shapes and other features for deft grasping, but also that they precisely control finger gestures to complete specific, delicate manipulation tasks.

[0003] Among them, tendon-driven dexterous manipulators mimic the tendon structure of human fingers. The actuators that generate finger movements can be fixed to the palm or wrist of the manipulator using tendon traction, thus combining a compact manipulator finger structure with flexible manipulation capabilities. Due to the large number of degrees of freedom of dexterous manipulators and their finger joints, fully driven tendon-driven dexterous manipulators often require a large number of actuators and complex control strategies to achieve high maneuverability. Conversely, underactuated tendon-driven dexterous manipulators can use fewer wires to jointly drive multiple joints on the fingers, allowing the manipulator fingers to adapt to the shape of the grasped object when grasping. However, the motions between the joints of underactuated fingers are coupled. Current underactuated manipulator designs make it difficult to individually control the position of a finger joint and adjust the rotational stiffness of any joint. Therefore, these dexterous manipulators struggle to achieve both dexterity and maneuverability. Summary of the Invention

[0004] The purpose of the embodiments of the present application is to provide a reconfigurable manipulator that can individually adjust the rotational stiffness of each finger joint in any direction, so that the manipulator has both under-actuated adaptability and full-actuated maneuverability to cope with a variety of general service scenario tasks.

[0005] In one aspect of an embodiment of the present application, a reconfigurable manipulator is provided, comprising a servo drive module and a pneumatic drive module connected to the servo drive module, and an underactuated finger disposed on the pneumatic drive module, wherein the underactuated finger is rotationally connected to the pneumatic drive module;

[0006] In which, the under-actuated finger at least includes a proximal finger end rotation joint, a middle finger joint, a distal finger end rotation joint and a terminal finger joint connected in sequence, and the pneumatic drive module is connected to the proximal finger end rotation joint; the proximal finger end rotation joint and the distal finger end rotation joint are respectively connected to the pneumatic drive module to provide positive air pressure through the pneumatic drive module to adjust the rotational stiffness of the proximal finger end rotation joint and the distal finger end rotation joint in any direction.

[0007] Optionally, the under-actuated fingers include three, and the pneumatic driver module includes a rotating base for correspondingly mounting the three under-actuated fingers; the three rotating bases are respectively connected to the servo motors of the servo driver module;

[0008] The three under-actuated fingers include an under-actuated thumb and two under-actuated index fingers. The rotating base corresponding to the under-actuated thumb can rotate 360° in a horizontal plane, and the rotating bases corresponding to the two under-actuated index fingers are driven by the gear set of the servo drive module and the servo motor to achieve reverse rotation.

[0009] Optionally, the proximal finger end rotary joint and the distal finger end rotary joint have the same structure, the proximal finger end rotary joint comprises a joint component, both ends of the joint component extend to form axial supports, wherein the axial support on one side is sequentially sleeved with a flexion return spring, a flexion locking ratchet, a flexion locking air cavity, a joint connector, and an extension steering torsion spring; the axial support on the other side is sequentially sleeved with an extension return spring, an extension locking ratchet, an extension locking air cavity, the joint connector, and the extension steering torsion spring, and the two joint connectors are symmetrically arranged on the joint component;

[0010] The flexion locking air cavity and the extension locking air cavity are both annular, and are respectively provided with air pressure conduits for connection with the pneumatic drive module.

[0011] Optionally, a limit key is provided on the axial support, a connector support plate is provided on the joint connector, a limit key slot is provided on the connector support plate toward the axial support, and the limit key passes through the limit key slot and is clamped with the connector support plate.

[0012] Optionally, a torsion spring groove is provided on the axial support and the joint connector respectively, and the extension steering torsion spring is clamped in the corresponding torsion spring groove of the axial support and the torsion spring groove of the joint connector.

[0013] Optionally, asymmetric radial flexion ratchet teeth are arranged circumferentially on the inner wall of the flexion locking ratchet disc to engage with the circumferentially arranged flexion matching teeth on the inner wall of the joint component, and the tooth surface of the flexion ratchet teeth is respectively on both sides with an inclined surface and a vertical surface, and the inclination angle of the inclined surface is any acute angle.

[0014] Optionally, a limit node is further provided on the inner wall of the flexion locking ratchet disc to coaxially cooperate with the limit slot on the joint connector.

[0015] Optionally, it also includes a tendon rope, which is connected to the pin on the distal phalanx of the finger, and passes through the tendon rope groove on the periphery of the joint component of the distal finger rotation joint, around the pin on the middle phalanx of the finger, the tendon rope groove on the periphery of the joint component of the proximal finger rotation joint and the pin on the joint connector of the proximal finger rotation joint, and finally connected to the drive wheel of the tendon rope servo motor of the servo drive module.

[0016] Optionally, the structure of the middle phalanx of the finger and the terminal phalanx of the finger is the same, and the middle phalanx of the finger includes a phalanx air pressure conduit, a phalanx rigid fixed base, a soft outer shell layer and a soft covering thin layer connected in sequence, the phalanx rigid fixed base, the soft outer shell layer and the soft covering thin layer form a closed cavity, a granular layer and an inelastic filter are arranged in the closed cavity, the granular layer is arranged close to the phalanx rigid fixed base, the phalanx air pressure conduit is connected to the pneumatic drive module and the conduit hole on the phalanx rigid fixed base, and the air pressure in the closed cavity is changed by air pressure drive.

[0017] Optionally, the particle layer includes a plurality of spherical particles, and the material of the spherical particles is a rigid material; the mesh size of the inelastic filter is smaller than the diameter of the spherical particles.

[0018] The reconfigurable manipulator provided by the embodiment of the present application has an under-actuated finger rotation set on a pneumatic drive module, and the pneumatic drive module is set on a servo drive module; the under-actuated finger at least includes a proximal finger end rotation joint, a finger middle phalanx, a distal finger end rotation joint and a finger end phalanx connected in sequence, and the pneumatic drive module is connected to the proximal finger end rotation joint; the proximal finger end rotation joint and the distal finger end rotation joint are respectively connected to the pneumatic drive module, and the positive air pressure provided by the pneumatic drive module can adjust the rotational stiffness of the proximal finger end rotation joint and the distal finger end rotation joint in any direction, thereby realizing bidirectional and independent rotational stiffness adjustment of the proximal finger end rotation joint and the distal finger end rotation joint. In this way, the rotational stiffness of the flexion direction and the extension direction of the finger rotation joint can be independently controlled. By setting different stiffness combinations between the finger joints, the mechanical gripper can exhibit various grasping methods. Compared with the existing technology, the manipulator provided in this embodiment adjusts the rotational stiffness of the distal fingertip rotational joint and the proximal fingertip rotational joint to achieve under-actuated grasping or decoupling to individually control the position of each rotational joint, so that the manipulator has both under-actuated adaptive capability and full-actuated maneuverability to cope with a variety of general service scenario tasks. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 is a schematic diagram of the structure of the reconfigurable manipulator provided in this embodiment;

[0021] Figure 2 Schematic diagram of the underactuated finger structure of the reconfigurable manipulator provided in this embodiment;

[0022] Figure 3 is an exploded view of the proximal fingertip rotation joint of the reconfigurable manipulator provided in this embodiment;

[0023] Figure 4 is a side view of the proximal fingertip rotation joint of the reconfigurable manipulator provided in this embodiment;

[0024] Figure 5 yes Figure 4 Middle GG cross-section;

[0025] Figure 6 This is an exploded view of the middle knuckle of the finger of the reconfigurable manipulator provided in this embodiment.

[0026] Icons: 1-underactuated thumb; 2-first index finger; 3-second index finger; 4-pneumatic actuator module; 41-thumb rotation base; 42-first index finger rotation base; 43-second index finger rotation base; 5-servo actuator module; 11-finger end knuckle; 111-end knuckle connecting pin hole; 112-end knuckle tendon pin hole; 12-distal finger end rotation joint; 1201-extension steering torsion spring; 1202-extension steering torsion spring; 12 03-joint connector; 1204-joint connector; 1205-flexion locking air cavity; 1206-extension locking air cavity; 1207-flexion locking ratchet; 1208-extension locking ratchet; 1209-flexion return spring; 1210-extension return spring; 1211-joint component; 1203a-limiting keyway; 1203b-connector support plate; 1203e-limiting slot; 1207b-limiting joint; 1211a- Axial support; 1211b - tendon groove; 1211c - limit key; 1211d - torsion spring groove; 1212 - flexion direction; 1213 - extension direction; 1203c - torsion spring groove; 1203d - joint connector pin hole; 1205a - air pressure tube; 1207a - flexion spur tooth; 1211e - joint component connection pin hole; 1211f - flexion mating tooth; 13 - middle phalanx of finger; 131 - phalanx air pressure tube ;132-rigid fixing base of knuckle;1321-connecting pin hole of rigid fixing base of knuckle;1322-pin hole of tendon rope of knuckle;1323-catheter hole;133-granular layer;134-inelastic filter screen;135-soft shell layer;1351-hole;136-soft covering thin layer;137-soft tissue of knuckle;14-proximal swivel joint;141-tendon rope groove of proximal swivel joint;142-composite hole of proximal swivel joint. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application.

[0028] In the description of this application, it should be noted that the terms "inner" and "outer" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the product of this application is typically placed when in use. These terms are intended solely to facilitate the description of this application and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" and the like are used solely for distinction and should not be construed as indicating or implying relative importance.

[0029] It should also be noted that, unless otherwise expressly specified or limited, the terms "disposed" and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0030] At present, general robot application scenarios not only require dexterous manipulators to adapt well to the features of unknown objects such as their shape to achieve dexterous grasping, but also expect them to be able to accurately control the finger posture to complete specific fine manipulation tasks. For tendon-driven dexterous manipulators, existing design solutions often only use the under-actuated compliance for dexterous grasping and cannot effectively decouple and control the position of each finger joint to achieve fine manipulation. Some joint designs can directly lock or adjust the rotational stiffness of the joints. However, existing joint designs with adjustable stiffness cannot adjust the joint stiffness in any direction (finger flexion direction 1212 and extension direction 1213), so these dexterous manipulators are difficult to achieve both high dexterity and maneuverability. In addition, current dexterous manipulators cannot form a stable force seal between the fingers to grasp daily objects with smooth or thin surfaces that are difficult to grasp, such as tableware, cards, etc.

[0031] In view of this, and to solve the above problems, the embodiments of the present application provide a reconfigurable manipulator based on variable stiffness joints and adsorbable variable stiffness composite knuckles (hereinafter referred to as the manipulator). The manipulator is equipped with air cavity-ratchet composite joints to achieve individual adjustment of the rotational stiffness of each finger joint in any direction, so that the manipulator has both under-actuated adaptive capabilities and full-actuated maneuverability to cope with a variety of general service scenario tasks. In addition, the manipulator is equipped with adjustable stiffness and adsorbable knuckles to provide robust force sealing and improve the success rate of grasping. At the same time, it gives the articulated dexterous manipulator an adsorbable grasping mode to solve the problem of grasping flat objects commonly found in life.

[0032] For details, please refer to Figure 1 As shown, an embodiment of the present application provides a reconfigurable manipulator, comprising: a servo drive module 5 and a pneumatic drive module 4 connected to the servo drive module 5, and an under-actuated finger provided on the pneumatic drive module 4, wherein the under-actuated finger is rotationally connected to the pneumatic drive module 4;

[0033] Among them, the under-actuated finger at least includes a proximal finger rotation joint 14, a middle finger joint 13, a distal finger rotation joint 12 and a terminal finger joint 11 connected in sequence, and the pneumatic driver module 4 is connected to the proximal finger rotation joint 14; the proximal finger rotation joint 14 and the distal finger rotation joint 12 are respectively connected to the pneumatic driver module 4 to provide positive air pressure through the pneumatic driver module 4 to adjust the rotational stiffness of the proximal finger rotation joint 14 and the distal finger rotation joint 12 in any direction.

[0034] The number of under-actuated fingers can be any number, but in order to facilitate grasping, the number of under-actuated fingers should include at least two. The following is explained by taking three under-actuated fingers as an example. The three under-actuated fingers include an under-actuated thumb 1 and two under-actuated index fingers, and the two under-actuated index fingers are respectively a first index finger 2 and a second index finger 3; the servo drive module 5, the pneumatic drive module 4 and the under-actuated fingers are stacked in sequence, and the three under-actuated fingers are rotatably arranged on the pneumatic drive module 4 to form a gripper, and the three under-actuated fingers are all mounted on a rotating base on the pneumatic drive module 4 and rotate with the rotating base.

[0035] The pneumatic drive module 4 includes a rotating base for correspondingly mounting three under-actuated fingers; the three rotating bases are respectively connected to the servo motors of the servo drive module 5 .

[0036] Each of the three under-actuated fingers corresponds to a rotation base, wherein the under-actuated thumb 1 corresponds to the thumb rotation base 41, the first index finger 2 corresponds to the first index finger rotation base 42, and the second index finger 3 corresponds to the second index finger rotation base 43. The thumb rotation base 41, the first index finger rotation base 42, and the second index finger rotation base 43 are respectively driven by the rotation servo motors in the servo drive module 5.

[0037] Furthermore, the rotating base corresponding to the under-actuated thumb 1 can rotate 360° in the horizontal plane, and the rotating bases corresponding to the two under-actuated index fingers are driven by the gear set and servo motor of the servo drive module 5 to achieve opposite and synchronous rotation.

[0038] The thumb rotating base 41 can be driven at any angle. The first index finger rotating base 42 and the second index finger rotating base 43 are jointly driven by a gear set and a rotary servo motor located in the servo drive module 5, allowing the two rotating bases to rotate in opposite directions at the same speed. Specifically, the first index finger rotating base 42 and the second index finger rotating base 43 are respectively connected to two gears, and the two gears are meshed. One of the gears is connected to the servo motor. When the servo motor drives the connected gear to rotate, the other meshed gear rotates in the opposite direction, thereby achieving the first index finger rotating base 42 and the second index finger rotating base 43 rotating in opposite directions at the same speed.

[0039] The purpose of rotating at the same speed in opposite directions is to maintain symmetry between the first and second index finger rotating bases 42, 43 during their movement. The plane of symmetry is the median perpendicular plane defined by any common perpendicular segment to the rotational axes of the first and second index finger rotating bases 42, 43. By driving the corresponding rotating bases of the three under-actuated fingers through the servo drive module 5, the three under-actuated fingers can form claws in a variety of rotational configurations to grasp objects of varying shapes and characteristics.

[0040] The structures and assembly methods of the three underactuated fingers are exactly the same, such as Figure 2 As shown, each under-actuated finger includes at least a proximal finger rotation joint 14, a middle finger joint 13, a distal finger rotation joint 12 and a terminal finger joint 11 connected in sequence. The proximal finger rotation joint 14 and the distal finger rotation joint 12 have exactly the same structure and size, and the terminal finger joint 11 and the middle finger joint 13 have basically the same structure, and only the size is different.

[0041] It should be noted that the proximal finger rotation joint 14 and the middle finger joint 13 can be regarded as a group of finger joint structures, and the distal finger rotation joint 12 and the terminal finger joint 11 can be regarded as a group of finger joint structures. The under-actuated finger of this application includes the above two groups of finger joint structures; of course, the number of groups of finger joint structures is not limited to the above two groups, and can also include more than three groups of finger joint structures. The settings are referred to above and will not be repeated here.

[0042] For example, the proximal finger end rotary joint 14, the middle finger joint 13, the distal finger end rotary joint 12 and the distal finger joint 11 are rigidly connected by inserting pins into the pin holes of each structure. This connection method has the advantage of easy installation and disassembly. For example, Figure 4 Middle joint component connecting pin hole 1211e, joint connector connecting pin hole 1203d, Figure 6 The middle finger joint rigid fixing base connection pin hole 1321 and Figure 2 The end knuckles in the middle are connected to the pin holes 111, etc., and the pins and pin holes match to achieve a rigid connection.

[0043] The proximal fingertip rotary joint 14 and the distal fingertip rotary joint 12 are respectively connected to the pneumatic drive module 4, which can provide positive air pressure to the proximal fingertip rotary joint 14 and the distal fingertip rotary joint 12 respectively, and adjust the rotational stiffness of the proximal fingertip rotary joint 14 and the distal fingertip rotary joint 12 in any direction separately through the positive air pressure, thereby realizing bidirectional independent rotational stiffness adjustment.

[0044] Thus, the reconfigurable manipulator provided in the embodiment of the present application includes an underactuated finger, the underactuated finger rotation is set on the pneumatic drive module 4, and the pneumatic drive module 4 is set on the servo drive module 5; the underactuated finger includes at least a proximal finger end rotary joint 14, a finger middle phalanx 13, a distal finger end rotary joint 12 and a finger end phalanx 11 connected in sequence, and the pneumatic drive module 4 is connected to the proximal finger end rotary joint 14; the proximal finger end rotary joint 14 and the distal finger end rotary joint 12 are respectively connected to the pneumatic drive module 4, and the positive air pressure provided by the pneumatic drive module 4 can respectively adjust the rotational stiffness of the proximal finger end rotary joint 14 and the distal finger end rotary joint 12 in any direction, thereby realizing bidirectional and independent rotational stiffness adjustment of the proximal finger end rotary joint 14 and the distal finger end rotary joint 12. In this way, the rotational stiffness of the flexion direction 1212 and the extension direction 1213 of the finger rotary joint is independently controlled. By setting different stiffness combinations between the finger joints, the mechanical gripper can exhibit various grasping methods. Compared with the existing technology, the manipulator provided in this embodiment adjusts the rotational stiffness of the distal fingertip rotational joint 12 and the proximal fingertip rotational joint 14 to achieve under-actuated grasping or decoupling to individually control the position of each rotational joint, so that the manipulator has both under-actuated adaptive capability and full-actuated maneuverability to cope with a variety of general service scenario tasks.

[0045] Furthermore, the structures of the proximal finger end rotation joint 14 and the distal finger end rotation joint 12 are the same. Taking the proximal finger end rotation joint 14 as an example, Figure 3 As shown, the proximal fingertip rotation joint 14 includes a joint component 1211, and both ends of the joint component 1211 extend to form axial supports 1211a, wherein the axial support 1211a on one side is sequentially sleeved with a flexion return spring 1209, a flexion locking ratchet 1207, a flexion locking air cavity 1205, a joint connector 1203, and an extension steering torsion spring 1201; the axial support 1211a on the other side is sequentially sleeved with an extension return spring 1210, an extension locking ratchet 1208, an extension locking air cavity 1206, a joint connector 1204, and an extension steering torsion spring 1202, and the joint connector 1203 and the joint connector 1204 are symmetrically arranged on the joint component 1211.

[0046] The flexion locking air cavity 1205 and the extension locking air cavity 1206 are both annular, and are respectively provided with air pressure conduits 1205 a for connection with the pneumatic driver module 4 .

[0047] Among them, the extension steering torsion spring 1201 and the extension steering torsion spring 1202, the flexion locking air cavity 1205 and the extension locking air cavity 1206, the flexion locking ratchet 1207 and the extension locking ratchet 1208, the flexion return spring 1209 and the extension return spring 1210 are components with the same structure and size; the joint connecting member 1203 and the joint connecting member 1204 are mirror-symmetrical structures. The axial support 1211a on the joint component 1211 supports and locks the above components. Figure 3 It can be seen that the joint component 1211 includes a rectangular body and a disc, and axial supports 1211a extend from both ends of the disc respectively. The general shape of the above components is also a disc, which can be mounted on the axial supports 1211a.

[0048] The flexion locking air cavity 1205 is annular, forming a hollow air cavity, and is made of silicone, or elastic materials such as rubber, and is connected to the pneumatic drive module 4 through an air pressure conduit 1205a; the extension locking air cavity 1206 is configured similarly.

[0049] A limit key 1211c is provided on the axial support 1211a, and a connector support plate 1203b is provided on the joint connector 1203. A limit key slot 1203a is provided on the connector support plate 1203b toward the axial support 1211a, and the limit key 1211c passes through the limit key slot 1203a and is engaged with the connector support plate 1203b.

[0050] A limit key 1211c is provided on the side wall of each axial support 1211a, and the limit key 1211c on each side passes through the corresponding limit key slot 1203a and is engaged with the corresponding connector support plate 1203b. Figure 3 As shown, the axial support 1211a is a cylinder, and the limit key 1211c protrudes from the side wall of the axial support 1211a; the joint connector 1203 includes a rectangular body and a connector support plate 1203b connected to the top of the body, the connector support plate 1203b is a disc, and a protruding cylinder is provided on the disc. The cylinder and the axial support 1211a are coaxially arranged, and the limit key groove 1203a is located on the side wall of the protruding cylinder; when assembling the proximal fingertip rotation joint 14, the limit key 1211c of the axial support 1211a passes through the limit key groove 1203a on the joint connector 1203 and is then clamped by the connector support plate 1203b, thereby preventing the joint connector 1203 and the joint component 1211 from moving axially along the installation axis. This installation method does not require additional installation tools such as pins and is easy to load and unload.

[0051] For the extension steering torsion spring 1201, torsion spring grooves are respectively provided on the axial support 1211a and the joint connector 1203, and the extension steering torsion spring 1201 is clamped in the torsion spring groove 1211d of the axial support 1211a and the torsion spring groove 1203c of the joint connector 1203.

[0052] The torsion spring groove 1211d of the axial support 1211a is located on the side wall of the axial support 1211a of the cylinder. The torsion spring groove 1203c on the joint connecting member 1203 is as shown in FIG. Figure 4 As shown, when the tendon rope is relaxed, the extension steering torsion spring 1201 passively provides an extension torque to the proximal fingertip rotation joint 14 through its own stored elastic potential energy.

[0053] Asymmetric radial flexion ratchet teeth 1207a are arranged circumferentially on the inner wall of the flexion locking ratchet 1207 to engage with the circumferentially arranged flexion matching teeth 1211f on the inner wall of the joint component 1211. The tooth surface of the flexion ratchet tooth 1207a is flanked by an inclined surface and a vertical surface, respectively, and the inclination angle of the inclined surface is any acute angle.

[0054] like Figure 5 As shown, flexion locking ratchet disc 1207 is circumferentially arranged with asymmetrical radial flexion ratchet teeth 1207a (as an example, flexion locking ratchet disc 1207 has a total of 36 flexion ratchet teeth 1207a, and this number is adjustable). Flexion ratchet teeth 1207a mate with flexion mating teeth 1211f on joint component 1211. The tooth surfaces of flexion ratchet teeth 1207a and flexion mating teeth 1211f mate with each other, and the tooth surfaces of flexion ratchet teeth 1207a are formed by an inclined surface and a perpendicular surface (relative to the plane of the disc), respectively. The inclined surface can have any acute angle, and the degree of the angle determines the difficulty of adjusting the stiffness of the revolute joint. In other words, the inclined surfaces and vertical surfaces on both sides of each bent ratchet tooth 1207a on the bent locking ratchet 1207 are engaged with the corresponding tooth grooves of the bent mating tooth 1211f to form meshing surfaces, and the ratchet teeth and their mating tooth grooves on both sides of each tooth meshing surface respectively include an inclined surface and a vertical surface.

[0055] A limit joint 1207b is also provided on the inner wall of the flexion locking ratchet 1207, coaxially mating with the limit groove 1203e on the joint connector 1203. The coaxial mating of the limit joint 1207b and the limit groove 1203e forms a limit structure that synchronizes the rotational movement of the flexion locking ratchet 1207 and the joint connector 1203. The connection method of the axial support 1211a on the other side and the various components is similar, and can be referred to as described above.

[0056] Therefore, the present application has the function of adjusting the rotational stiffness of the joint through air pressure, wherein the components or structures used to achieve variable stiffness in the extension direction 1213 (while being in a locked state in the flexion direction 1212) include: a flexion locking air cavity 1205, a flexion locking ratchet 1207, a flexion return spring 1209 and a flexion mating tooth 1211f.

[0057] When the flexion locking air cavity 1205 is in a relaxed state (not filled with positive air pressure), the flexion return spring 1209 pushes the flexion locking ratchet 1207 away from the flexion engagement tooth 1211f, quickly switching the proximal fingertip rotational joint 14 to an underactuated, zero-stiffness state. The ratchet stop 1207b and the ratchet stop groove 1203e are coaxially mated, forming a limiting structure that synchronizes the rotational movement of the flexion locking ratchet 1207 and the joint connector 1203. The above-mentioned component structure, constraints, and working mode on the flexion side are also applicable to the components on the extension side (extension return spring 1210, extension locking ratchet 1208, extension locking air cavity 1206, and joint connector 1204), thereby achieving locking of the joint's rotational movement in the extension direction 1213 and variable stiffness adjustment of the flexion direction 1212.

[0058] The structure and principle of the distal finger end rotary joint 12 are the same as those of the proximal finger end rotary joint 14 , and will not be described in detail here.

[0059] In addition, the under-actuated finger also includes a tendon rope (not shown in the figure), which is connected to the pin on the distal phalanx 11 of the finger, and passes through the tendon rope groove 1211b on the periphery of the joint part 1211 of the distal finger rotation joint 12, around the pin on the middle phalanx 13 of the finger, the tendon rope groove 1211b on the periphery of the joint part 1211 of the proximal finger rotation joint 14 and the pin on the joint connector 1203 of the proximal finger rotation joint 14, and finally connected to the drive wheel of the tendon rope servo motor of the servo drive module 5.

[0060] The tendon cord is used to achieve under-actuation. The tendon cord can be an inelastic cord such as a high-tenacity fiber cord or a steel wire cord. Specifically, the tendon cord is connected to the pin inserted into the tendon cord pin hole 112 of the distal phalanx of the finger. The tendon cord then passes through the tendon cord groove 1211b of the distal fingertip rotary joint 12, and passes around the pin in the tendon cord pin hole 1322 of the middle phalanx of the finger as a fixed pulley. Finally, it passes through the tendon cord groove 141 of the proximal fingertip rotary joint and the pin in the proximal fingertip rotary joint composite hole 142, and is connected to the tendon cord servo motor drive wheel located in the servo drive module 5. Through the drive of the tendon cord servo drive motor and the traction of the tendon cord, the distal fingertip rotary joint 12 and the proximal fingertip rotary joint 14 can be coupled or rotated independently. Whether the finger grasps an object in an under-actuated manner depends on the stiffness relationship between the flexion direction 1212 and the extension direction 1213 of the two rotary joints on the same finger. The tendon rope installation method and the connection installation method between the knuckles and joints are a modular design and installation method, which allows the number of joints and knuckles to be freely changed by directly connecting the fingers with pins and re-threading the tendon ropes.

[0061] In summary, for Figure 4 When the variable stiffness composite joint (distal finger rotation joint 12) in the assembled state is to be locked in the flexion direction 1212 and to adjust the stiffness in the extension direction 1213, the pneumatic drive module 4 applies positive air pressure (relative to the standard atmospheric pressure) to the flexion locking air cavity 1205 through the air pressure tube 1205a, thereby expanding the flexion locking air cavity 1205, pushing the flexion locking ratchet 1207 to compress the flexion return spring 1209, and finally making the flexion ratchet tooth 1207a fit tightly with the flexion mating tooth 1211f. By changing the size of the forward driving air pressure, the expansion degree of the flexion locking air cavity 1205 and the pressure on the flexion locking ratchet 1207 are changed, thereby effectively adjusting the pressure of the flexion ratchet tooth 1207a of the flexion locking ratchet 1207 on the flexion mating tooth 1211f; when the rotary joint rotates, the flexion mating tooth 1211f needs to be applied with torque to overcome the expansion thrust of the flexion locking air cavity 1205, thereby indirectly changing the rotational stiffness of the joint connector (joint connector 1203, joint connector 1204, connected by pins to form a rigid whole) and the joint component 1211 relative to the joint rotation axis. Furthermore, under the same driving air pressure, the asymmetry of the ratchet tooth pair (flexed ratchet tooth 1207a and flexed mating tooth 1211f) results in a rotational stiffness in the flexion direction 1212 that is significantly greater than that in the extension direction 1213. (The above is an illustrative example of locking and variable stiffness in one direction; locking in the opposite extension direction 1213 and adjusting stiffness in the flexion direction 1212 can be achieved in the same manner by components on the other side of the joint.) The dexterous manipulator can flexibly adjust the rotational stiffness of each rotational joint in all directions using air pressure, based on actual grasping and environmental interaction requirements.

[0062] In addition to the above-mentioned air pressure driven variable stiffness function, the present invention also has the finger middle joint 13 and the finger end joint 11 as joints with adjustable stiffness and adsorption function. The finger middle joint 13 and the finger end joint 11 have the same structure but different sizes. Take the finger middle joint 13 as an example. Figure 6 As shown, the middle phalanx 13 of the finger includes a phalanx air pressure conduit 131, a phalanx rigid fixed base 132, a soft outer shell layer 135 and a soft covering thin layer 136 connected in sequence. The phalanx rigid fixed base 132, the soft outer shell layer 135 and the soft covering thin layer 136 form a closed cavity, and a granular layer 133 and an inelastic filter screen 134 are arranged in the closed cavity. The granular layer 133 is arranged close to the phalanx rigid fixed base 132. The phalanx air pressure conduit 131 is connected to the pneumatic drive module 4 and the conduit hole 1323 on the phalanx rigid fixed base 132, and the air pressure in the closed cavity is changed by air pressure drive.

[0063] The middle phalanx 13 of the finger includes a phalanx air pressure conduit 131, a rigid base 132 for the phalanx, a granular layer 133 formed by filling particles, an inelastic filter 134, a soft outer shell 135, and a soft covering layer 136. The granular layer 133, inelastic filter 134, soft outer shell 135, and soft covering layer 136 constitute the phalanx soft tissue 137. The inelastic filter 134, soft outer shell 135, and soft covering layer 136 are adhered to the phalanx soft tissue 137 using a silicone rubber adhesive. The soft outer shell 135 is then bonded to the rigid base 132 for the phalanx using instant adhesive to form a closed cavity. The phalanx air pressure conduit 131 connects to the pneumatic actuator module 4 and the conduit hole 1323 of the rigid base 132 for the phalanx, and changes the air pressure within the closed cavity of the phalanx soft tissue 137 through air pressure actuation.

[0064] For example, the material of the spherical particles of the particle layer 133 of the present application is a rigid material; the mesh size of the inelastic filter 134 is smaller than the diameter of the spherical particles.

[0065] The closed cavity is filled with about 80% of its volume with spherical particles with a diameter of 0.1 mm to 1.0 mm to form a particle layer 133. The filled particles are glass (or rigid materials such as plastic, metal, etc.). The inelastic filter 134 is required to be an inelastic (plastic) filter with a mesh size smaller than the diameter of the spherical particles. The soft shell layer 135 and the soft covering layer 136 can be soft structures made of the same or different silicone rubber materials. The holes 1351 of the soft shell layer 135 are approximately cylindrical through holes. The soft covering layer 136 is a silicone rubber film with a thickness greater than 100 microns. The film is used to form a complete closed cavity and has good deformation ability.

[0066] Reference Figure 6As shown, the operating principle of the adsorbable variable-stiffness knuckle (the middle knuckle 13 of the finger) is that the pneumatic actuator module 4 applies negative pressure (relative to standard atmospheric pressure) to the closed air cavity of the knuckle via the knuckle air pressure conduit 131. Under the action of the negative pressure, the soft shell layer 135 contracts and squeezes the filler particles in the granular layer 133, increasing the friction between the filler particles. Due to the mutual squeezing and friction, the previously relaxed filler particles are difficult to generate relative motion, indirectly increasing the deformation stiffness of the knuckle soft tissue 137, which is primarily composed of particles. The deformation stiffness of the knuckle soft tissue 137 can be adjusted by varying the negative pressure. Due to the obstruction of the inelastic filter 134, the filler particles cannot enter the holes 1351 of the soft shell layer 135. Under the action of negative pressure, the soft covering layer 136 shrinks and deforms toward the inside of the hole 1351, and finally fits the inner wall of the through hole; at this time, when there is a relatively smooth object outside the soft covering layer 136, a temporary closed cavity will also be formed between the soft covering layer 136 and the object. The shrinkage and deformation process of the above-mentioned soft covering layer 136 will also form a negative pressure in the above-mentioned temporary closed cavity, and the negative pressure will eventually manifest as the soft covering layer 136 producing an adsorption effect on the object.

[0067] In addition to the above components, all other components (members) not specifically described in this application are assumed to be rigid components (members) and can be produced by 3D printing technology (or metal processing, etc.). The connection and fixation between components are achieved by pins (or screws, etc.).

[0068] In summary, the present application is an under-actuated manipulator consisting of a variable stiffness joint driven by air pressure and an adsorbable variable stiffness finger joint. The variable stiffness composite joint (the distal finger rotation joint 12 and the proximal finger rotation joint 14) realizes bidirectional independent rotation stiffness adjustment through positive air pressure drive; the adsorbable variable stiffness finger joint soft tissue 137 realizes the variable stiffness function and produces an adsorption effect at the same time through air pressure drive. Therefore, the reconfigurable manipulator provided in the embodiment of the present application adopts two air cavities with adjustable air pressure in the variable stiffness composite joint to realize independent control of the rotation stiffness of the flexion direction 1212 and the extension direction 1213 of the finger rotation joint. By setting different stiffness combinations between the finger joints, the mechanical gripper can exhibit a variety of grasping methods. Compared with the prior art, this manipulator adjusts the rotational stiffness of the distal finger end rotational joint 12 and the proximal finger end rotational joint 14 to achieve under-actuated grasping or decouple the position of each rotational joint. In addition, because the proposed rotational joint has a one-way locking characteristic, the manipulator can achieve the function of resisting the falling of the grasped object with high extension stiffness and further grasping the object with relatively low flexion rotational stiffness. The manipulator's bidirectional adjustable grasping stiffness greatly expands the application range of dexterous robotic claws and improves their application safety. Regarding the adsorbable variable stiffness knuckles, compared with the prior art, this composite knuckle achieves variable stiffness and adsorption functions in a compact structure. The adjustable stiffness of the knuckle tissue improves the manipulator's flexibility to the object's shape and the robustness of its grasping. Secondly, the adsorption function of the knuckle tissue expands the application range of the dexterous manipulator's grasping by generating suction on the grasped object (such as adsorption and grasping of extremely thin and other difficult-to-pick-up objects).

[0069] In addition, in the reconfigurable manipulator of the present application, three under-actuated fingers are taken as an example. Each under-actuated finger includes a proximal finger end rotation joint 14, a middle finger joint 13, a distal finger end rotation joint 12 and a terminal finger joint 11 connected in sequence. Then, the three under-actuated fingers contain a total of six variable stiffness composite joints and six adsorbable variable stiffness finger joints. The joints and finger joints are connected end to end and installed on the under-actuated thumb 1, the first index finger 2 and the second index finger 3. Combined with the tendon drive of each finger mentioned above (the tendon drive servo motor is located in the servo drive module 5), the manipulator can achieve a rich range of finger postures. Each finger can not only use the variable stiffness composite joint to independently switch to the under-actuated mode or arbitrarily control the position of a certain joint, but also use its own rotating base (41, 42, 43) to adjust the finger direction (the steering drive servo motor is located in the servo drive module 5) to grasp objects of different shapes and sizes with different gripper postures.

[0070] Furthermore, when not in contact with the object to be grasped, the closed cavity of the knuckle soft tissue 137 is in a standard atmospheric pressure state, the filling particles can move freely, the knuckle soft tissue 137 is in a relatively low stiffness, and the soft covering layer 136 is in a relaxed state; after the gripper and the knuckle soft tissue 137 contact the object, the knuckle soft tissue 137 will flexibly adhere to the surface of the object and envelop the shape of the object; after the contact between the knuckle soft tissue 137 and the object is stable, the knuckle soft tissue 137 is evacuated to a negative pressure state by the knuckle air pressure tube 131, so that the knuckle soft tissue 137 increases its stiffness according to the aforementioned particle friction principle to form a stable grasping force, and causes the soft covering layer 136 to generate an adsorption grasping force on the object according to the aforementioned contraction deformation principle.

[0071] It should also be pointed out that the reconfigurable manipulator provided in the embodiment of the present application, each submodule is designed based on a modular concept, and with the corresponding pneumatic drive module 4 and servo drive module 5, the number of fingers of the manipulator can be any number (the above example is three identical fingers). It should be understood that in the structure of the aforementioned single under-actuated finger, the configuration of two rotary joints and two phalanges is only a commonly used finger matching. Since the structural dimensions of the rotary joints (the distal finger rotary joint 12 and the proximal finger rotary joint 14) are exactly the same, and the installation method is consistent with the distal and proximal ends of the phalanges (the finger end phalanges 11 and the finger middle phalanges 13), it is completely feasible to add or delete several rotary joints and middle phalanges on the under-actuated finger. It only requires changing the tendon length without changing the structure of the submodule. Therefore, the number of under-actuated fingers of the reconfigurable manipulator, as well as the number and matching of the rotary joints and phalanges in each under-actuated finger can be set according to specific needs, and this application does not make specific restrictions on this.

[0072] The above description is merely an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, various modifications and variations of the present application are possible. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A reconfigurable manipulator, characterized in that: include: A servo drive module, a pneumatic drive module connected to the servo drive module, and an under-actuated finger disposed on the pneumatic drive module, wherein the under-actuated finger is rotationally connected to the pneumatic drive module; The underactuated finger comprises at least a proximal finger end rotary joint, a middle finger joint, a distal finger end rotary joint and a terminal finger joint connected in sequence, and the pneumatic actuator module is connected to the proximal finger end rotary joint; the proximal finger end rotary joint and the distal finger end rotary joint are respectively connected to the pneumatic actuator module, so that the pneumatic actuator module provides positive air pressure to adjust the rotational stiffness of the proximal finger end rotary joint and the distal finger end rotary joint in any direction; The structures of the proximal finger end rotary joint and the distal finger end rotary joint are the same, the proximal finger end rotary joint comprises a joint component, both ends of the joint component extend to form axial supports, wherein the axial support on one side is sequentially sleeved with a flexion return spring, a flexion locking ratchet, a flexion locking air cavity, a joint connector, and an extension steering torsion spring; the axial support on the other side is sequentially sleeved with an extension return spring, an extension locking ratchet, an extension locking air cavity, the joint connector, and the extension steering torsion spring, and the two joint connectors are symmetrically arranged on the joint component; Asymmetric radial flexion ratchet teeth are arranged circumferentially on the inner wall of the flexion locking ratchet disc to engage with the circumferentially arranged flexion matching teeth on the inner wall of the joint component. The two sides of the tooth surface of the flexion ratchet tooth are an inclined surface and a vertical surface respectively, and the inclination angle of the inclined surface is any acute angle.

2. The reconfigurable manipulator according to claim 1, characterized in that: The under-actuated fingers include three, and the pneumatic driver module includes a rotating base for correspondingly mounting the three under-actuated fingers; the three rotating bases are respectively connected to the servo motors of the servo driver module; The three under-actuated fingers include an under-actuated thumb and two under-actuated index fingers. The rotating base corresponding to the under-actuated thumb can rotate 360° in a horizontal plane, and the rotating bases corresponding to the two under-actuated index fingers are driven by the gear set of the servo drive module and the servo motor to achieve reverse rotation.

3. The reconfigurable manipulator according to claim 1 or 2, characterized in that: The flexion locking air cavity and the extension locking air cavity are both annular, and are respectively provided with air pressure conduits for connection with the pneumatic drive module.

4. The reconfigurable manipulator according to claim 3, characterized in that: A limit key is provided on the axial support, a connector support plate is provided on the joint connector, a limit key slot is provided on the connector support plate toward the axial support, and the limit key passes through the limit key slot and is clamped with the connector support plate.

5. The reconfigurable manipulator according to claim 3, characterized in that: The axial support and the joint connector are respectively provided with torsion spring grooves, and the extension steering torsion spring is clamped in the corresponding torsion spring grooves of the axial support and the joint connector.

6. The reconfigurable manipulator according to claim 1, characterized in that: A limiting node is also provided on the inner wall of the flexion locking ratchet disc to coaxially cooperate with the limiting groove on the joint connector.

7. The reconfigurable manipulator according to claim 3, characterized in that: The under-actuated finger also includes a tendon rope, which is connected to the pin on the terminal phalanx of the finger, and passes through the tendon rope groove on the periphery of the joint component of the distal finger rotation joint, around the pin on the middle phalanx of the finger, the tendon rope groove on the periphery of the joint component of the proximal finger rotation joint and the pin on the joint connector of the proximal finger rotation joint, and finally connected to the drive wheel of the tendon rope servo motor of the servo drive module.

8. The reconfigurable manipulator according to claim 1 or 2, characterized in that: The structure of the middle phalanx of the finger and the terminal phalanx of the finger are the same. The middle phalanx of the finger includes a phalanx air pressure conduit, a phalanx rigid fixed base, a soft outer shell layer and a soft covering thin layer connected in sequence. The phalanx rigid fixed base, the soft outer shell layer and the soft covering thin layer form a closed cavity. A granular layer and an inelastic filter are arranged in the closed cavity. The granular layer is arranged close to the phalanx rigid fixed base. The phalanx air pressure conduit is connected to the pneumatic drive module and the conduit hole on the phalanx rigid fixed base, and the air pressure in the closed cavity is changed by air pressure drive.

9. The reconfigurable manipulator according to claim 8, characterized in that: The particle layer includes a plurality of spherical particles, and the material of the spherical particles is a rigid material; the mesh size of the inelastic filter is smaller than the diameter of the spherical particles.

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