CN114986546A - Rigid-flexible coupling variable structure type paw - Google Patents

Abstract

The invention discloses a rigid-flexible coupling transformable paw, which comprises a transformable palm, air bag type five fingers, a back connecting piece, a boosting cylinder and a combined type sucking disc, wherein the transformable palm comprises a short thumb unfolding bone, a central metacarpal bone, a side unfolding bone of a little finger and a driving air bag, and the short thumb unfolding bone can realize the outward extension and the inward retraction of a thumb and is used for grabbing a cylindrical object; the little finger side expansion bone can realize the side expansion of the ring finger and the little finger and realize the gripping of a round object, one side of each boosting cylinder is connected with the proximal joint of the corresponding air bag type finger by a pin, and the other side of each boosting cylinder is connected with the corresponding connection part of the back connecting piece by a pin; when the boosting cylinder is used for air intake, a piston rod of the boosting cylinder can drive corresponding air bag type fingers to bend, the combined sucker is formed by connecting and nesting the outer sucker and the inner sucker in a threaded manner, the adaptability of the invention to the shape, weight, surface characteristics and the like of a grabbed object is enhanced, the grabbing stability is improved, the response is quicker, the precision is improved, and the adjustment of the grabbing force can be finer.

Description

Rigid-flexible coupling variable structure type paw

Technical Field

The invention relates to the field of design of tail end structures of robots, in particular to a rigid-flexible coupling variable-structure paw.

Background

At present, the industrial field in China is developing towards the direction of short delivery time, individuation and digitization, the requirements on the flexibility and the intellectualization of a production line are continuously improved, the problems that the traditional robot is relatively single in end mechanism form, insufficient in flexibility, low in grabbing stability and the like are increasingly highlighted, and the requirements of compact flexible paws in the fields of logistics sorting, special-shaped workpiece grabbing, artificial limb application, man-machine integration, endowment and accompanying and attending are gradually increased. At present, manual picking is mainly used for picking fruits and vegetables, and along with rural labor loss, the development of a flexible paw with good flexibility, high stability, strong universality and high cost performance is a key for solving the problem of large-scale picking of fruits and vegetables. On the one hand, the grasping attention of ball fruits is more, the grasping research of cylindrical fruits and vegetables with large annual demand of cucumbers, corns and the like is less, and if a five-finger dexterous hand is adopted, the grasping is higher, the control is complex, and the inconvenience is brought to practical application. On the other hand, when picking fruits and vegetables with large mass such as apples, navel oranges, cucumbers and the like, the root of the fingers of the pneumatic paw with pure flexibility is generally deformed greatly, and the grasping stability during rapid sorting and carrying is difficult to guarantee. Therefore, in order to increase the strength of the gripper without losing its contact flexibility and versatility for gripping objects, it is necessary to design a rigid-flexible coupling gripper.

In the aspect of tail end structure design of robots in China, when objects with curved surfaces are grabbed, the design of a rigid two-finger paw and a V-shaped structure is mostly adopted, and a three-finger flexible paw, a five-finger dexterous hand or a trunk-type structure [ Peng, Liu, courageous, Yang, and the like ] with central symmetry are adopted, so that the application research of the soft mechanical paw in fruit and vegetable picking progresses [ J ]. agricultural engineering bulletin, 2018,34(9): 11-20; homberg B S, Katzschmann R K, Dogar M R, et al, robust predictive formatting with a soft robot hand [ J ]. Autonomous Robots,2018-04-19.https:// doi.org/10.1007/S10514-018-. The first mode is widely applied in the industrial field, and when the first mode is applied to fruit grabbing, some students only widen fingers to increase the grabbing force, but the stability of the fruit moving and carrying is not high; the second mode is difficult to grab the cylindrical fruits and vegetables from the side; the third mode is complex to control, generally adopts a rigid structure, and has limited real-time flexibility for grabbing small-sized fruits. Some students imitate hands of people to adopt split arrangement of three fingers to improve the adaptability and the grabbing stability of the hands of the students, but the students are mostly limited to rigid materials, when objects with flexible surfaces are grabbed, uneven force application on two sides is easy to occur, so that local stress is overlarge, and the grabbed objects deform [3] Liangda Yao, Zhang Chang, clamp self-adaptive under-actuated hand parameters are optimized and the stability is analyzed [ J ] robot, 2017(3),282 + 290; spadaford F, muzzippa M; bruno F, et al, design and construction of a robot hand protocol for underserver applications [ J ]. IFAC-paperONLINE, 2015, (48-2): 294-. The calculation and control of the position of the end is difficult when the trunk-like structure is used to grasp the article. Wen Li et al added a suction cup structure on the basis of the trunk-like structure to enhance the gripping stability, but the uncertainty of displacement when gripping fruits of different weights and sizes still exists [ Xie Z, Domel AG, An N, et al, Octopus Arm-implanted threaded Soft instruments with a packer for Improved gripping [ J ]. Soft Robotics,2020,2.25.DOI: https:// doi.org/10.1089/soro.2019.0082 ]. In recent years, the application of multi-finger flexible claws constructed based on bending pneumatic muscles and multi-cavity drivers is increased, but the stability and the service life of the claws are influenced when the claws are used for grabbing articles with larger mass or quickly sorting the articles; the higher the pressure, the greater the degree of finger flexion, and thus the more difficult it is to grasp large-sized, high-mass objects [ Zhu M, Xie M, Lu X, Okada S, Kawamura S, A soft cosmetic finger with self-powered triboeelectric therapy sensor based on multi-material 3D printing, Nano Energy (2020), doi: https:// doi.org/10.1016/j.nanoen.2020.104772 ]. There are also scholars who design multi-stage pneumatic muscle-driven external-flexible-internal-rigid multi-finger paws, but the contact flexibility of the grasping face during fruit and vegetable picking is difficult to guarantee [ less money. In general, existing gripper forms have limited adaptability to the shape, size, weight, and surface characteristics of the object being grasped. Therefore, a multifunctional paw which is stronger in universality, higher in stability and flexible in grasping contact surface needs to be developed, the adaptability of the paw is improved, and the operation efficiency in the processes of picking and distributing fruits and vegetables is practically improved. Therefore, the novel rigid-flexible coupling paw integrating the flexible fingers, the link mechanism and the sucker is provided, so that the comprehensive performance of the paw made of different materials is optimized.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides the rigid-flexible coupling variable structure type paw which has the advantages of enhanced adaptability to the shape, weight, surface characteristics and the like of a grabbed object, improved grabbing stability, quicker response, improved precision and more precise adjustment of grabbing force.

The purpose of the invention is realized by the following technical scheme.

A rigid-flexible coupling variable claw comprises a variable palm, an air bag type five finger, a back connecting piece, a boosting cylinder and a combined sucker. The variable palm 1 comprises a short thumb unfolding bone, a central metacarpal bone, a side unfolding bone of a little finger and a driving air bag. The thumb short stretching bone can realize the outward extension and the inward retraction of the thumb and is used for grasping a cylindrical object; the little finger side expansion bone can realize the side expansion of the ring finger and the little finger and realize the gripping of the round object. 5 fingers in the five fingers of the air bag type are different in length and thickness so as to meet the requirements of grabbing different objects, particularly special-shaped objects. The back connecting piece comprises 2 vertical supporting rods, a main connecting rod, an auxiliary connecting rod I and an auxiliary connecting rod II. The boosting type cylinder comprises 5 cylinders, namely a thumb cylinder, a forefinger cylinder, a middle finger cylinder, a ring finger cylinder and a little finger cylinder; one side of each boosting cylinder is connected with the proximal end joint of the corresponding air bag type finger through a pin, and the other side of each boosting cylinder is connected with the corresponding connection position of the back connecting piece through a pin. When the boosting cylinder is used for air intake, the piston rod of the boosting cylinder drives the corresponding air bag type finger to bend, and compared with a pure flexible paw, the boosting cylinder can provide larger holding force and higher response speed. The combined sucker is formed by connecting and nesting an outer sucker and an inner sucker through threads. The outer side sucker is used for sucking the top of large fruits such as oranges and apples when the large fruits are grabbed, and the inner side sucker is used for sucking and grabbing small round fruits.

The thumb short expansion bone of the metamorphic palm is matched with the pin shaft between the central metacarpal bones to drive the air bag to drive so that the thumb air bag 2-1 can conveniently realize the outward extension and the inward retraction in the vertical plane; the gripping of the cylindrical object is convenient to realize.

The little finger side exhibition bone is connected with the eighth through hole and the 4 tenth through holes in the central metacarpal sector area, so that the little finger side exhibition bone can realize the side exhibition of the ring finger and the little finger in different angles in the horizontal plane, and the gripping of a round object is realized.

The thumb air bag is connected with the first through hole and the 4 second through holes in the extended fan-shaped boss of the thumb short extension bone, so that the thumb air bag can swing at four mounting positions conveniently, and grabbing of round and special-shaped objects can be realized.

The combined sucker is formed by nesting the outer sucker and the inner sucker through threaded connection, and can adapt to grabbing of objects with different sizes and weights.

The vertical three-cavity structure with the air bag type five fingers sequentially becoming flexible and the surface multi-group array type sucker and fingertip V-shaped array type multi-stripe structure 26 enable the adaptability of the invention to different surface characteristics of a grabbed object to be enhanced.

A rigid-flexible coupling variable-structure paw comprises an assistance cylinder, a combined sucking disc, an air bag type five-finger root cavity body thickened at the top, rigid nails arranged at the tops of fingertips and the like, so that the grabbing stability of the paw is improved.

A rigid-flexible coupling variable-structure paw comprises an index finger air bag, a middle finger air bag, a ring finger air bag and a little finger air bag, wherein two dents are arranged on two joints of a simulated hand along the finger direction, so that the rapid bending deformation of the fingers during grabbing is facilitated; the piston rod of the boosting cylinder is connected with the airbag type five fingers through a first double-lug ring at the concave position of the near end, and the position and the posture of the device are determined more quickly because the boosting cylinder is rigid. The rigid nail arranged on the top of the fingertip can prevent the shaking of the tail end clamping point to a certain extent, thereby improving the action precision.

An air bag type five-finger vertical three-cavity structure which is sequentially flexible can realize the adjustment of the pose and the rough adjustment and fine adjustment of the holding force; the thumb gasbag, forefinger gasbag, middle finger gasbag, ring finger gasbag, little finger gasbag pressure of gasbag type five fingers can independently be adjusted, and the air feed pressure of two air inlets of combination formula sucking disc can independently be adjusted, all makes this device grab the regulation of holding power more meticulous, satisfies the user demand of different occasions.

Compared with the prior art, the invention has the advantages that:

compared with the traditional paw, the rigid-flexible coupling variable-structure paw has the advantage that the adaptability to the shape, weight, surface characteristics and the like of a grabbed object is enhanced.

The pin shaft between the thumb short expansion bone 1-1 and the central metacarpal bone 1-2 of the metamorphic palm 1 is matched to drive the air bag 1-4 to drive the air bag 2-1 to conveniently realize the outward extension and the inward retraction in the vertical plane; the gripping of the cylindrical object is convenient to realize.

The little finger side expansion bone 1-3 is connected with the eighth through hole 10-1 and the 4 tenth through holes 10-2 in the sector area 10 of the central metacarpal bone 1-2, so that the little finger side expansion bone 1-3 can realize the side expansion of the ring finger and the little finger at different angles in the horizontal plane, and the gripping of a round object is realized.

The thumb air bag 2-1 is connected with a first through hole 7 and 4 second through holes 8 on a fan-shaped boss 6 extending out of the thumb short extension bone 1-1, so that the thumb air bag 2-1 can swing at four mounting positions conveniently, and a round and special-shaped object can be grabbed.

The combined type sucker 5 is formed by nesting an outer sucker 5-1 and an inner sucker 5-2 in a threaded connection mode, and the total installation height of the combined type sucker 5 and the installation height of the inner sucker 5-2 relative to the outer sucker 5-1 can be adjusted, so that the device can adapt to grabbing of objects with different sizes and weights.

The vertical three-cavity structure that the air sac type five fingers 2 become flexible in sequence, the surface multi-group array type suction cups 22 and the fingertip V-shaped array type multi-stripe structure 26 enable the adaptability of the invention to different surface characteristics of a grabbed object to be enhanced.

Compared with the traditional flexible paw, the rigid-flexible coupling variable-structure paw has the advantage that the grabbing stability is improved. The grabbing stability of the invention is improved by thickening the top of the cavity at the root part of the air bag type five-finger 2, arranging a rigid nail 25 at the top of the finger tip and the like by the aid of the assistance type air cylinder 4, the combined type sucking disc 5 and the air bag type five-finger 2; the air bag type five-finger 2 three-number vacuum cavity 19-3, the multiple groups of array type suckers 22 on the surface and the fingertip V-shaped array type multi-stripe structure 26 can effectively prevent the object from sliding in the grabbing process, and the grabbing stability is further improved.

Compared with the traditional flexible paw, the rigid-flexible coupling variable-structure paw has the advantages that the response is quicker, and the precision is improved. The forefinger air bag 2-2, the middle finger air bag 2-3, the ring finger air bag 2-4 and the little finger air bag 2-5 simulate two joints of a human hand along the finger direction and are provided with two dents 20, so that the fingers can be quickly bent and deformed when being grabbed; the piston rod of the boosting cylinder 4 is connected with the air bag type five fingers 2 through a first double-ear ring 21 at the concave part of the near end, and the position and the posture of the device are determined more quickly because the boosting cylinder 4 is rigid in structure. The rigid nail 25 provided on the tip of the fingertip can prevent the tip holding point from being shaken to some extent, and thus the operation accuracy is improved.

Compared with the traditional paw, the rigid-flexible coupling variable-structure paw has the advantage that the gripping force can be more finely adjusted. The vertical three-cavity structure with the sequentially flexible air bag type five fingers 2 can realize the adjustment of the pose and the rough adjustment and fine adjustment of the holding force; the pressure of the thumb airbag 2-1, the index finger airbag 2-2, the middle finger airbag 2-3, the ring finger airbag 2-4 and the little finger airbag 2-5 of the airbag type five-finger 2 can be independently adjusted, and the air supply pressure of the two air inlets of the combined type sucker 5 can be independently adjusted, so that the adjustment of the gripping force of the device can be more refined, and the use requirements of different occasions can be met.

Drawings

Fig. 1 is a rigid-flexible coupling variable structure type paw assembly fig. 1.

Fig. 2 is a rigid-flexible coupling variable structure type paw assembly fig. 2.

Fig. 3 is a bottom structure view of the reconfigurable palm 1.

Fig. 4 is a back structure diagram of the convertible palm 1.

Fig. 5 is a cross-sectional view of the thumb bladder 2-1.

Fig. 6 is a left side view of the thumb bladder 2-1.

Fig. 7 is a cross-sectional view of the middle finger bladder 2-3.

Fig. 8 is a first axial view of the middle finger balloon 2-3.

FIG. 9 is a second isometric view of middle finger bladder 2-3.

FIG. 10 is an isometric view of thumb connector 2-6-1.

FIG. 11 is an isometric view of the four finger connector 2-6-2.

Fig. 12 is a sectional view of the combined suction cup 5.

Fig. 13 is an isometric view of the modular suction cup 5.

Fig. 14 is an isometric view of a rigid fingernail 25.

Detailed Description

The invention is described in detail below with reference to the drawings and specific examples.

As shown in fig. 1, the rigid-flexible coupling variable paw comprises a variable palm 1, an air bag type five fingers 2, a back connecting piece 3, a boosting cylinder 4 and a combined type sucker 5. The variable palm 1 comprises a thumb short expanded bone 1-1, a central metacarpal bone 1-2, a little finger side expanded bone 1-3 and a driving air bag 1-4. The thumb short stretching bone can realize the outward extension and the inward retraction of the thumb and is used for grasping a cylindrical object; the little finger side expansion bone can realize the side expansion of the ring finger and the little finger and realize the gripping of the round object. 5 fingers in the air bag type five fingers 2 are different in length and thickness so as to meet the requirements of grabbing different objects, particularly special-shaped objects. The back connecting piece 3 comprises 2 vertical supporting rods 3-1, a main connecting rod 3-2, an auxiliary connecting rod I3-3 and an auxiliary connecting rod II 3-4. The boosting cylinder 4 comprises 5 cylinders, namely a thumb cylinder 4-1, a forefinger cylinder 4-2, a middle finger cylinder 4-3, a ring finger cylinder 4-4 and a little finger cylinder 4-5; one side of each boosting cylinder 4 is connected with the proximal end joint of the corresponding air bag type finger by pins 4-6, and the other side is connected with the corresponding connection part of the back connecting piece 3 by pins 4-7. When the boosting cylinder is used for air intake, the piston rod of the boosting cylinder drives the corresponding air bag type finger to bend, and compared with a pure flexible paw, the boosting cylinder can provide larger holding force and higher response speed. The combined type sucking disc 5 is formed by connecting and nesting an outer sucking disc 5-1 and an inner sucking disc 5-2 through threads. The outer side sucker is used for sucking the top of large fruits such as oranges and apples when the large fruits are grabbed, and the inner side sucker is used for sucking and grabbing small round fruits.

As shown in fig. 3, the modified palm 1 comprises a thumb short abduction bone 1-1, a central metacarpal bone 1-2, a little finger side abduction bone 1-3 and a driving air bag 1-4. The thumb short stretching bone 1-1 is used for connecting the variable structure type palm 1 with the thumb air bag 2-1; the central metacarpal bone 1-2 is used for connecting the variable palm 1 with the forefinger air bag 2-2 and the middle finger air bag 2-3; the little finger side expansion bone 1-3 is used for connecting the variable palm 1 with the ring finger air bag 2-4 and the little finger air bag 2-5. The thumb short spreading bone 1-1 is connected with the central metacarpal bone 1-2 through a pin shaft 1-5 and a nut 1-6. The thumb short stretching bone can rotate around the pin shaft 1-5, so that the thumb can extend outwards and retract inwards, and the thumb short stretching bone is used for grabbing cylindrical objects. The thumb short stretching bone 1-1 and the central metacarpal bone 1-2 are respectively provided with a first counter bore 1-7 for connecting and fixing the driving air bag 1-4. The driving air bags 1-4 provide power for the rotation of the thumb bone around the pin shafts 1-5. The thumb short stretching bone 1-1 is provided with an outward extending fan-shaped boss 6, the center of the circle is provided with a first through hole 7, and 4 second through holes 8 are uniformly arranged in the circumferential direction at an included angle of 45 degrees as a distance by taking the center of the circle as the center of the circle and are used for adjusting different installation angles of the thumb air bag 2-1, so that a circular and special-shaped object can be grabbed.

As shown in fig. 3 and 4, the central metacarpal bone 1-2 is composed of a triangular area 9, a sector area 10 and a connecting area 11. The triangular area 9 is provided with a threaded hole 9-1 and a second counter bore 9-2. The threaded hole 9-1 is used for connecting the combined type sucking disc 5; the second counter bore 9-2 is used for driving the connection of the air bag 1-4. The tail end of the triangular area 9 is provided with 2 connecting platforms 9-3 which form an angle of 45 degrees with the bottom surface of the central metacarpal bone in a stepped mode, and the angle of 45 degrees is set to reduce the action range of the air sac type five fingers 2 under the conventional grabbing action, improve the response speed of the paw, reduce the loss of the air sac type five fingers 2 during repeated operation and prolong the service life.

2 six through holes 9-4 are respectively arranged on the upper part of the middle metacarpal bone, and are used for connecting the center metacarpal bone 1-2 with the forefinger air bag 2-2 and the middle finger air bag 2-3. The head and the tail of the bevel edge of the triangular area 9 are provided with two bulges for arranging a number seven through hole required by the installation of the pin shaft 1-5, the root of the bevel edge of the triangular area 9 is provided with a number one blind hole 9-5 with internal thread, and the top of the bevel edge of the triangular area 9 is provided with a number eight through hole 9-6 for connecting the central metacarpal bone 1-2 with the short abduction bone 1-1 of the thumb. The triangular area 9, the fan-shaped area 10 and the connecting area 11 are flush at the bottom. Wherein, the top of the sector 10 is lower than the top of the triangular area 9 by a certain distance, which is convenient for the installation of the little finger side expansion bones 1-3. The middle position of the sector area 10 is provided with an eighth through hole 10-1, and 4 tenth through holes 10-2 are uniformly distributed with an included angle of 30 degrees in the circumferential direction by taking the eighth through hole as the circle center, so that the lateral expansion bone 1-3 of the little finger can realize the horizontal lateral expansion of the ring finger and the little finger at different angles, and the gripping of a round object is realized. The connecting area 11 is provided with an external thread connector 11-1 for connecting the tail end of a robot or an automatic mechanism; in order to ensure that the joint has certain strength, the external thread connector and the main body area of the central metacarpal 1-2 are provided with a transition area 11-2, and the top and the bottom of the transition area are flush with the triangular area 9. The back of the central metacarpal bone 1-2 is provided with 2 threaded blind holes 9-7 and 9-8 which are respectively positioned in the triangular area 9 and the sector area 10 and are used for being connected with 2 vertical support rods 3-1. The inclined edge of the triangular area 9 and the horizontal edge of the transition area 11-2 form an included angle of 60 degrees.

As shown in fig. 3 and 4, the lateral abduction bones 1 to 3 of the little finger adopt a triangle-like structure, the root part is narrow, and the tail end is wide. The root structure is arc-shaped 12, a third counter bore 13 is formed in the center of the arc, a fourth counter bore 14 is formed in the center of the arc at a certain distance along the installation direction of the air bag type finger, the distance between the two counter bores is equal to the distance between an eighth through hole 10-1 and a tenth through hole 10-2, and the fixing device is used for fixing the side expansion bone 1-3 of the little finger at different horizontal installation angles. The tail end of the little finger side stretching bone 1-3 is provided with 2 connecting platforms 15 which form an angle of 45 degrees with the bottom surface of the central metacarpal in a stepped manner, and the connecting platforms are respectively provided with 2 eleven through holes 16 for connecting the variable structure type palm 1 with the ring finger air bag 2-4 and the little finger air bag 2-5.

As shown in fig. 1, 2 and 4, the driving airbags 1-4 are generally of an inverted V-shaped hollow structure, with a top wave and a bottom V-shaped, so that the driving airbags are more convenient to rapidly bend and deform under the action of air pressure compared with the conventional wave-shaped multi-cavity structure. One end of the foot support is provided with an air inlet 17 on the side surface, the head and the tail are respectively provided with two rectangular platforms, and 1 twelve through hole 18 is respectively arranged on the platforms and is respectively used for connecting the foot support with a thumb short stretching bone 1-1 and a central metacarpal bone 1-2. The driving air bag is formed by 3D printing or film inversion of a silica gel material,

as shown in figure 1, the air bag type five-finger 2 consists of a thumb air bag 2-1, a forefinger air bag 2-2, a middle finger air bag 2-3, a ring finger air bag 2-4, a little finger air bag 2-5 and a finger connecting piece 2-6. The air bag type five fingers 2 simulate the design of five fingers of a human hand, and have different overall lengths and thicknesses so as to be suitable for different grabbing objects.

As shown in fig. 5 and 6, the thumb airbag 2-1 adopts a longitudinal two-cavity structure 45, which is composed of a root cavity 46 and a fingertip cavity 47. The two are connected by an air passage. The top of the root cavity 46 is a V-shaped structure 46-1, and the bottom of the root cavity 46 is horizontal 46-2, so that the strength of the outer side of the root cavity 46 when the thumb airbag 2-1 grips an object is ensured. An air inlet 46-3 is formed in the outer surface of the top of the root cavity 46 near the middle of the root. The outer surface of the side edge of the root cavity 46 is symmetrically provided with 2 nineteen through holes 46-4 for connecting with the thumb connecting piece 2-6-1. The top of the near end of the fingertip cavity 47 is provided with a dense corrugated section 47-1, and the bottom of the near end of the fingertip cavity 47 is provided with an inverted V-shaped section 47-2 which is used for simulating the joint of the thumb of a human hand, so that the thumb air bag 2-1 is easy to bend inwards under the action of air pressure. The distal tip of the fingertip cavity 47 is a thicker horizontal solid structure 47-3, which is aimed at ensuring the strength and accuracy of the thumb bladder 2-1 in grasping an object. The bottom of the fingertip cavity 47 is a hollow cavity, the bottom surface of the fingertip cavity is an arc-shaped structure 47-4, and the V-shaped array type multi-stripe structure 26 is printed or pasted on the outer surface of the bottom surface, so that the contact surface and the friction force are increased. The outer surface of the top of the fingertip cavity 47 is provided with a pair of zero-number double earrings 47-5 for connecting with the tail end of a piston rod of the thumb cylinder 4-1.

As shown in fig. 7, 8 and 9, the index finger airbag 2-2, the middle finger airbag 2-3, the ring finger airbag 2-4 and the little finger airbag 2-5 are all of a multi-cavity structure 19, and different from the conventional multi-cavity driver which is uniformly distributed, the airbag type five-finger 2 in the patent is provided with two recesses 20 along the finger direction for simulating the rest four finger airbags of two joints of a human hand except the big finger airbag 2-1, the top of the airbag type five-finger is a rectangular recess 20-1, the bottom of the corresponding position is provided with an inverted V-shaped recess 20-2, and the size of the proximal end of the inverted V-shaped recess 20-2 is larger than that of the distal end, so that the rapid bending deformation during finger grabbing is facilitated. A first double-lug ring 21 connected with the tail end of a piston rod of the boosting type cylinder 4 is arranged at the position of a rectangular recess 20-1 in the top of the near end, and the first double-lug ring 21 is symmetrically arranged by taking the axis of the corresponding finger as a symmetry axis. The length of three segments of fingers (the root part 9-4, the middle part 9-5 and the tip 9-6) divided by taking the sunken part as a boundary is determined according to the length proportion of the adult human hand. Each section of finger is composed of 1 to 3 rectangular cavities which are communicated with each other. The finger is cut open along the central axis of the finger, the air bag type five-finger 2 adopts a vertical three-cavity structure from top to bottom along the height direction and consists of a first deformation cavity 19-1, a second contact force control cavity 19-2 and a third vacuum cavity 19-3. The three materials become soft in sequence, the heights of the three cavities are reduced in sequence, and the third vacuum cavity 19-3 can effectively prevent the object from sliding in the grabbing process, so that the grabbing stability is improved. The connection between the three cavities can be formed by adopting a paste type or multi-material layerwise 3D printing, and can also be formed by adopting a uniform material in an integrated manner. The first deformation cavity 19-1 is used for controlling the overall shape of the finger; the second contact force control cavity 19-2 is lower in height and used for fine adjustment of contact force; the third vacuum cavity 19-3 is used for adsorbing a weight, and whether vacuum is started or not is determined according to actual needs. The air bag type five-finger 2 gripping surface is provided with a plurality of groups of array type suction cups 22. Four convex hooks 23 are arranged at four corners of the air bag type five fingers 2 at the periphery of each group of array type suckers, when only part of the gripping surfaces need to be adsorbed, dense plastics are adopted for the other part of the contact surfaces which do not need to be adsorbed or are not suitable for adsorption to be hung on the hooks at the four corners, the corresponding suckers are sealed, and the adaptability of the novel electric gripping device to different gripping objects and surfaces is improved. When grabbing heavy objects, in order to improve the strength of the finger root, the top material of the root cavity is thicker 24 to reduce deformation; in order to reduce the shaking of the tail end and improve the precision by clamping the object by the paw, a rigid fingernail 25 is arranged at the tail end of the air sac type five finger 2. The rigid fingernail 25 adopts a rectangular structure, and the tail end of the air bag type five-finger 2 is installed by surface adhesion; or as shown in fig. 14, the rigid nail 25 adopts a rectangular structure and inverted dovetail structures 25-1 on two sides, a cylindrical boss 25-2 is arranged in the middle of one end of the rigid nail and is matched with a cylindrical groove in a horizontal slot at a certain height above the tail end of the airbag type five finger 2 to play a role in guiding and positioning, and the end part of the inverted dovetail structure 25-1 is installed by adopting a method of interference fit and adhesive tape sealing. The length of the rigid fingernail 25 extends to a certain distance longer than the bottom, and the V-shaped array type multi-stripe structure 26 is printed or stuck on the outer surface of the bottom of the fingertip, so that the contact surface and the friction force are increased. In order to facilitate the connection between the first double-ear ring 21 at the first recess of the air bag type five-finger 2 and the tail end of the piston rod of the boosting cylinder 4, a slope type structure 27 is adopted near the top end of the cavity body so as to prevent the two from interfering during the action. The side surface of the root part of the air bag type five-finger 2 is provided with a group of through holes 28, which comprises a first deformation cavity 19-1 air inlet hole 28-1 and 2 finger connecting holes 28-2 which are positioned on the middle axis, and air inlet holes of a second contact force control cavity 19-2 and a third vacuum cavity 19-3 which are positioned on two sides of the middle axis. The air inlet hole 28-3 of the second contact force control cavity 19-2 and the air inlet hole 28-4 of the third vacuum cavity 19-3 are respectively positioned at the corresponding heights of the second contact force control cavity 19-2 and the third vacuum cavity 19-3.

The airbag type five-finger 2 adopts a modular design. The air bag type five-finger 2 generally adopts a multi-cavity structure, and the height and the length of a single cavity are kept unchanged for different fingers; when the length of the middle finger is increased compared with that of the index finger, the number of the proximal joint cavities is increased; the width of the index finger, the middle finger, the ring finger and the little finger decreases in sequence. Each finger of gasbag type five fingers 2 can supply air independently as required or simultaneously to satisfy the demand that different objects snatched.

As shown in fig. 1, 10 and 11, the finger attachments 2-6 include a thumb attachment 2-6-1 and a four finger attachment 2-6-2. The thumb connecting piece 2-6-1 adopts a structure similar to an inverted triangle, the root part of the thumb connecting piece is an arc 48, a fifth counter bore 49 is arranged at the circle center of the arc 48, a sixth counter bore 50 is outwards arranged along the axis direction, and the two counter bores are respectively connected with the first through hole 7 and the second through hole 8 on the thumb short expansion bone 1-1, so that the thumb air bag 2-1 can be conveniently adjusted and fixed at different installation angles. The lateral surface of the outer end of the thumb connecting piece 2-6-1 is provided with a first cylindrical boss structure 51 which is used for being connected with 2 nineteen through holes 46-4 on the thumb air bag 2-1.

As shown in fig. 11, the four-finger connecting piece 2-6-2 adopts a T-shaped rigid structure and consists of a vertical part 29 and a cross rib plate 30 which extends transversely. The upper surface of the rib plate 30 is provided with two symmetrical thirteen through holes 31 for connecting the airbag type five fingers 2 with 2 sixth through holes 9-4 on the connecting table 9-3 and 2 eleventh through holes 16 on the connecting table 15. The top of the vertical part 29 is provided with three air inlets, and the air inlet 29-1 arranged in the middle is communicated with the inlet of the first deformation cavity 19-1 through an outlet 29-4 of a built-in first L-shaped channel. The air inlets 29-2, 29-3 are symmetrically arranged on both sides of the air inlet 29-1. The air inlet 29-2 is communicated with the inlet of the second contact force control cavity 19-2 through an outlet 29-5 of a second L-shaped channel arranged in the air inlet; the air inlet 29-2 is communicated with the inlet of the third vacuum cavity 19-3 through the outlet 29-6 of the built-in third L-shaped channel. The upper part and the lower part of the outlet 29-4 are respectively provided with a cylindrical lug boss-added connector 29-7 with the same size, which is used for being connected with 2 finger connecting holes 28-2 on the side surface of the root part of the airbag type five fingers 2. The diameter of the cylindrical part of the connector 29-7 is consistent with that of the finger connecting hole 28-2, and the boss of the connector 29-7 is of a hemispherical structure, and the diameter of the boss is slightly 1.3 times of that of the cylindrical part, so that the connector 29-7 is prevented from falling off after being inserted into the airbag type five-finger 2.

As shown in FIG. 2, the back connecting piece 3 comprises 2 vertical supporting rods 3-1, a main connecting rod 3-2, an auxiliary connecting rod one 3-3 and an auxiliary connecting rod two 3-4. One of the functions of the 2 vertical support rods 3-1 is to support the back connecting piece 3 and the boosting cylinder 4 to a certain height so as to ensure that the boosting cylinder 4 can better adapt to the moving range of the airbag type five fingers 2; the second function of the 2 vertical support rods 3-1 is to fix the main connecting rod 3-2. The bottom ends of the 2 vertical support rods 3-1 are provided with external threads which are connected with 2 threaded blind holes 9-7 and 9-8 on the back surface of the central metacarpal bone 1-2, the top parts of the 2 vertical support rods are also provided with external threads which are connected with two No. fifteen through holes 32 on the main connecting rod 3-2 and then fastened by a No. eight nut 33. The diameter of the smooth part in the middle of the 2 vertical support rods 3-1 is slightly larger than the outer diameter of the threads at the head and the tail, so that the step formed at the top can be used for supporting the main connecting rod 3-2, the installation is simplified, and the total mass of the device is not too large.

As shown in FIG. 2, the main connecting rod 3-2 adopts a T-shaped 34 plus a bevel edge 35 structure. The outer side of the T-shaped 34I cross bar 34-1 is vertically and symmetrically provided with 2 pairs of second double lug rings 34-2 which are respectively used for movably connecting the main connecting rod 3-2 with the first lug ring 52 at the root of the forefinger cylinder 4-2 and the middle finger cylinder 4-3. The straight bar 34-3 of the T-shaped 34I is slightly wider than the cross bar I and the bevel edge 35 to ensure strength. The inclined edge 35 and the first straight rod 34-3 form an included angle of 50 degrees. The center point of the intersection point of the inclined edge 35 and the first straight rod 34-3 is taken as a boundary, and the inclined edge 35 can be divided into a long edge section 35-1 and a short edge section 35-2, wherein the length ratio of the long edge section to the short edge section is 2: 1. The middle of the tail end of one side of the long side section 35-1 is provided with a seventeen through hole 35-3 which is positioned right above the eighth through hole 10-1 of the sector area 10 of the central metacarpal bone 1-2 and is used for being movably connected with the auxiliary connecting rod I3-3, so that the auxiliary connecting rod I3-3 can horizontally stretch along with the little finger side stretching bone 1-3. And a fourth double-ear ring 35-4 is arranged at the bottom of the other side of the short side section 35-2. The axis direction of the fourth double-lug ring 35-4 forms an included angle of 30 degrees with the first straight rod 34-3, is located right above the pin shaft 1-5 and is used for movably connecting the main connecting rod 3-2 with the auxiliary connecting rod two 3-4, and the auxiliary connecting rod two 3-4 can conveniently extend and retract along with the thumb bone 1-1 under the driving of the driving air bag 1-4.

As shown in FIG. 2, the auxiliary connecting rod I3-3 adopts a T-shaped structure and is composed of a second cross rod 36 and a second straight rod 37. And 2 pairs of fifth double-lug rings 38 are vertically arranged on the outer side of the second cross rod 36 and are respectively used for movably connecting the auxiliary connecting rods I3-3 with the roots of the ring finger cylinders 4-4 and the small thumb cylinders 4-5. The second cross bar 37 can be divided into a long side section and a short side section by taking the center point of the intersection point of the second cross bar and the second straight bar 37 as a boundary, and the length ratio of the long side section to the short side section is 2: 1. Eighteen through holes 39 are formed in the tail ends of the second straight rods 37 and are used for being matched with the seventeen through holes 35-3 to achieve movable connection with the main connecting rods 3-2 through pins.

As shown in figure 2, the auxiliary connecting rod II 3-4 adopts an L-shaped structure, and the outer side of the short side of the auxiliary connecting rod II is vertically provided with a No. 1 single lug ring 40 for movably connecting the auxiliary connecting rod II 3-4 with the main connecting rod 3-2. And the outer side of the long side of the second auxiliary connecting rod 3-4 is vertically provided with 1 pair of No. seven double lug rings 41 for movably connecting the second auxiliary connecting rod 3-4 with the root of the thumb cylinder 4-1.

As shown in fig. 1 and 2, the boosting cylinder 4 comprises 5 cylinders, namely a thumb cylinder 4-1, a forefinger cylinder 4-2, a middle finger cylinder 4-3, a ring finger cylinder 4-4 and a little finger cylinder 4-5. The cylinder bottom of the boosting cylinder 4 and the tail end of the piston rod are both in a single-lug ring structure. The thumb cylinder 4-1 adopts a multi-stage cylinder structure 42 due to a large moving range, and the rest four cylinders adopt single-stage cylinder structures. One side of each boosting cylinder 4 is connected with the proximal end joint of the corresponding air bag type finger by pins 4-6, and the other side is connected with the joint of the double ear ring corresponding to the back connecting piece 3 by pins 4-7. The length of the straight rod in the back connecting piece 3 is designed to ensure that the positions of all groups of double-lug ring structures for connecting the single-lug rings at the root parts of the boosting cylinders 4 are basically positioned right above or near the first double-lug ring 21 or the seventh double-lug ring 41 corresponding to the airbag type five fingers 2. The mounting height of the back connecting piece 3 and the length of the cylinder barrel of the boosting type cylinder 4 are designed to ensure that the airbag type five fingers 2 can be flattened at the nearest end, and the finger roots 9-4 of the corresponding fingers can be ensured to be perpendicular to the variable structure type palm 1 at the farthest end. When grabbing objects with different sizes and shapes, the rigid-flexible coupling variable-structure gripper has the advantages that the displacement of each cylinder in the boosting cylinder 4 is possibly different, so that a proportional directional control valve is required to be adopted for control, and the displacement of the cylinders can be adjusted in a stepless mode. The pressure control of each component of the air bag type five-finger 2 and the boosting type air cylinder 4 can be controlled by selecting a conventional pressure reducing valve or a proportional pressure reducing valve according to the use condition and the condition.

As shown in figures 12 and 13, the combined suction cup 5 is formed by nesting an outer suction cup 5-1 and an inner suction cup 5-2 in a threaded connection mode. The outer side sucker is used for sucking the top of large fruits such as oranges and apples when the large fruits are grabbed, and the inner side sucker is used for sucking and grabbing small round fruits. The outer side sucker 5-1 and the inner side sucker 5-2 are both composed of a suction section 43 and a connecting rod 44. The connecting rod 44 comprises a first outer sucker connecting rod 44-1 and a second inner sucker connecting rod 44-2. The internal thread of the central cavity of the first outer sucker connecting rod 44-1 is matched with the external thread of the second inner sucker connecting rod 44-2. The top of the connecting rod 44 is provided with two air inlets, a large air inlet 44-3 is communicated with the annular hollow cavity of the outer sucker connecting rod I44-1, and a small air inlet 44-4 is communicated with the top of the central cavity of the outer sucker 5-1. The position of the small air inlet 44-4 is higher than the top position of the inner sucker connecting rod II 44-2, so that the inner sucker 5-2 can supply air through the small air inlet 44-4 at the lower part and the upper part of the outer sucker 5-1 at different installation heights without being blocked. The air passages of the outer side sucker 5-1 and the inner side sucker 5-2 are separated by the annular pipe 44-5, so that the air is prevented from communicating. The outer side of the connecting rod of the outer side sucker 5-1 is of an external thread structure and is matched with a threaded hole 9-1 in the central metacarpal bone 1-2, so that the installation height of the combined sucker 5 can be conveniently adjusted as required. The sucking section of the outer sucking disc 5-1 is of a conical hollow structure 43-1, relatively hard plastic is adopted, the sucking surface is of an annular structure 43-2, and small sections of four quadrant points are sealed at 43-3 positions, so that vacuum is formed as soon as possible, the outer sucking disc 5-1 is convenient to manufacture, and meanwhile the outer sucking disc 5-1 is not easy to deform. And the top annular area of the connecting rod 5-4 corresponding to the outer sucker 5-1 is sealed 44-6. The adsorption section of the inner side sucker 5-2 is of a corrugated sucker structure 45, and the material of the adsorption section is softer than that of the outer side sucker 5-1. The installation position of the inner side sucker 5-2 relative to the outer side sucker 5-1 can be conveniently adjusted; the two air supply devices can supply air independently, can work simultaneously or respectively, and are suitable for different requirements of grabbing objects and different appearance curved surfaces.

Each component of the rigid-flexible coupling variable-structure gripper can be formed by 3D printing, and the purpose is to facilitate processing, reduce cost and reduce the weight of the device. The small-size connecting piece that is not convenient for 3D to print can select standard component as required, guarantees that the installation of each part of this device, connection, cooperation have no problem.

The implementation case is as follows:

a rigid-flexible coupling variable-structure paw has multiple modes when in use:

1) in the adsorption mode 1, only the inner sucker 5-2 or the outer sucker 5-1 in the combined sucker 5 works. Is suitable for the adsorption and the grabbing of small objects such as small tomatoes and loquats or plane objects.

2) And in the adsorption mode 2, the outer sucker 5-1 and the inner sucker 5-2 in the combined sucker 5 work simultaneously. Is suitable for the adsorption and the grabbing of the peach and plum medium-type fruits or plane objects.

3) The grabbing mode 3 comprises a 2-3 grabbing mode and a 3-5 grabbing mode in the air bag type five-finger 2, wherein the former is suitable for grabbing a part of small-size objects, and the latter is suitable for grabbing medium-size or large-size but light-weight objects. The selection of the adsorption mode 1 or the 2-3 finger grabbing modes in the grabbing mode 3 for grabbing small-size objects depends on the characteristics of the grabbed objects, grabbing stability, control convenience and other factors, and the grabbing mode is selected according to actual conditions. In the mode, the air supply pressure of the first finger deformation cavity 19-1, the second contact force control cavity 19-2 and the third vacuum cavity 19-3 of each finger of the air bag type five-finger 2 can be adjusted in sequence, and the three work simultaneously or the two work simultaneously or according to actual conditions. The three are suggested to work simultaneously for grabbing the smooth object surface.

4) And in the adsorption grabbing mode 4, the air bag type five fingers 2 and the combined type sucker 5 work simultaneously. Is suitable for grabbing objects with relatively heavy mass such as small and medium-sized apples and oranges.

5) And a rigid-flexible coupling grabbing mode 5, a boosting cylinder 4 and the air bag type five fingers 2 work simultaneously. The gripper is suitable for grabbing objects with larger sizes and heavier masses.

6) The rigid-flexible coupling adsorption grabbing mode 6 is characterized in that the boosting type cylinder 4, the air bag type five fingers 2 and the combined type sucker 5 work simultaneously. Is suitable for grabbing apples, large oranges and even small grapefruits. Because the material of the air bag type five-finger 2 vertical three-cavity body is sequentially softened, when the first deformation cavity body 19-1, the second contact force control cavity body 19-2 and the third vacuum cavity body 19-3 of each finger work simultaneously, the mode can also be called a rigid-soft coupling adsorption grabbing mode.

One of the modes 3 to 6 can be selected for grasping a cylindrical object or other foreign object.

Parameters such as the angle of a short extended bone 1-1 of a thumb, the angle of a thumb air bag 2-1, the angle of a small finger side extended bone 1-3, the overall installation height of a combined type sucker 5, the installation height of an inner side sucker 5-2, the air bag type first finger deformation cavity 19-1 of each five fingers 2, the air supply pressure of a second contact force control cavity 19-2 and a third vacuum cavity 19-3, the air supply pressure of two air inlets of the combined type sucker 5, the air supply pressure of a driving air bag 1-4 and the like are adjusted according to actual use requirements under different working modes of the rigid-flexible coupling variable structure type paw. In order to make the parameter adjustment of the device too complicated during actual use, the device can be debugged first and then the optimal parameter combination or the proper working range is recorded, thereby improving the long-term working efficiency of the device. In the parameter selection, for the object with heavier mass, the appropriate parameter combination in the modes 4 to 6 is suggested to reduce the loss of the air bag type five fingers 2 and prolong the service life of the device.

The design of the rigid-flexible coupling variable-structure type paw variable-structure type palm 1 and the longitudinal and transverse designs of the air bag type five fingers 2 simulate a human hand, and the application of the boosting type air cylinder 4 and the combined type sucker 5 supplements the deficiency in strength of flexible materials. Compared with the conventional paw, the device has more complex structure; compared with the human hand, the device is reasonably simplified according to different application characteristics of rigid materials and flexible materials, and simultaneously makes full use of respective advantages of positive pressure driving and negative pressure driving. Therefore, the device has high comprehensive performance in the aspects of freedom degree, adaptability, stability, controllability, manufacturing cost, service life and the like, and has wide application field.

Claims (10)

1. A rigid-flexible coupling structure-changeable paw is characterized by comprising a structure-changeable palm, air bag type five fingers, a back connecting piece, a power-assisted cylinder and a combined type sucking disc, wherein the structure-changeable palm comprises a short thumb unfolding bone, a central metacarpal bone, a side unfolding bone of a little finger and a driving air bag, and the short thumb unfolding bone can realize the outward extension and the inward retraction of a thumb and is used for grabbing a cylindrical object; the little finger side expansion bone can realize the side expansion of the ring finger and the little finger and realize the gripping of a round object, the back connecting piece comprises 2 vertical supporting rods, a main connecting rod, an auxiliary connecting rod I and an auxiliary connecting rod II, and the boosting type cylinder comprises a thumb cylinder, a forefinger cylinder, a middle finger cylinder, a ring finger cylinder and a little finger cylinder; one side of each boosting cylinder is connected with a proximal end joint of a corresponding air bag type finger by a pin, and the other side of each boosting cylinder is connected with a corresponding connection part of the back connecting piece by a pin; when the boosting type cylinder admits air, a piston rod of the boosting type cylinder can drive corresponding air bag type fingers to be bent, the combined type sucker is formed by nesting an outer side sucker and an inner side sucker in a threaded connection mode, the outer side sucker is used for sucking the top of a large round fruit when the large round fruit is grabbed, and the inner side sucker is used for sucking and grabbing a small round fruit.

2. The rigid-flexible coupling metamorphic paw as recited in claim 1, wherein the pin between the thumb short expansion bone and the central metacarpal bone of the metamorphic palm is matched to drive the air bag to extend and retract in the vertical plane; for realizing the gripping of the cylindrical object.

3. The rigid-flexible coupling structure-changeable paw as claimed in claim 1, wherein the lateral expansion bone of the little finger is connected with the eight through holes and the 4 ten through holes in the central metacarpal sector, so that the lateral expansion bone of the little finger of the lateral expansion bone of the little finger can realize the lateral expansion of the ring finger and the little finger at different angles in the horizontal plane, and the gripping of a circular object is realized.

4. The rigid-flexible coupling variable-structure paw as claimed in claim 1, wherein the thumb airbag is connected with the first through hole and the 4 second through holes on the extended fan-shaped boss of the thumb short extension bone, so that the thumb airbag can swing at four mounting positions, and a round and irregular object can be grabbed.

5. The rigid-flexible coupling variable-structure paw as claimed in claim 1, wherein the combined suction cup is formed by nesting an outer suction cup and an inner suction cup through threaded connection, and can be used for grabbing objects with different sizes and weights.

6. The rigid-flexible coupling variable structure paw as claimed in claim 1, wherein the five fingers of the airbag type are provided with vertical three-cavity structure and surface multi-group array type sucking disc and fingertip V-shaped array type multi-stripe structure which are sequentially flexible.

7. The rigid-flexible coupling variable-structure paw as claimed in claim 1, wherein the top of the cavity at the root of the five fingers is thickened, and a rigid nail is arranged at the top of the finger tip.

8. The rigid-flexible coupling variable-structure paw as claimed in claim 1, wherein the forefinger air bag, the middle finger air bag, the ring finger air bag and the little finger air bag are provided with two recesses along two joints of a simulated human hand in the finger direction, so as to facilitate rapid bending deformation when fingers grasp; the piston rod of the boosting cylinder is connected with the airbag type five fingers through a first double-lug ring at the concave position of the near end.

9. The rigid-flexible coupling variable-structure paw as claimed in claim 6, wherein the airbag type five-finger sequentially flexible vertical three-cavity structure is used for realizing pose adjustment, rough adjustment and fine adjustment of gripping force; the pressure of the thumb air bag, the index finger air bag, the middle finger air bag, the ring finger air bag and the little finger air bag is independently adjusted, and the air supply pressure of the two air inlets of the combined type sucker is independently adjusted.

10. The rigid-flexible coupling metamorphic paw as recited in claim 1, wherein 5 fingers of said five fingers are different in length and thickness.

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