Self-adaptive grabbing mechanical finger of rigid-flexible coupling structure and driving method of self-adaptive grabbing mechanical finger

Abstract

The invention discloses a self-adaptive grabbing mechanical finger of a rigid-flexible coupling structure and a driving method thereof.The self-adaptive grabbing mechanical finger of the rigid-flexible coupling structure comprises a finger root part base, a parallel four-bar mechanism and a rigid-flexible coupling multi-knuckle elastic finger structure, and the parallel four-bar mechanism is fixed to a hole position of the finger root part base through a rotating shaft and a rolling bearing; the other end of the parallel four-bar mechanism fixedly bears a root base structure of the rigid-flexible coupling multi-knuckle elastic finger through a rolling bearing in the hole site, and the rigid-flexible coupling multi-knuckle elastic finger is connected with the rest part structure of the mechanical finger through a root base. According to the mechanical finger, self-adaptive stepless adjustment of the grabbing size and height and conformal fitting of the grabbing contour can be achieved according to the size and contour features of a grabbed target object. And stable fitting grabbing of target objects with different types, different sizes, different appearance contours, surface stiffness and gravity center distribution under different placement poses in a daily home service scene can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical fields of robot gripper design, grasping motion analysis, rigid-flexible coupling structure design, and dual-path parallel transmission mechanism, and particularly relates to an adaptive grasping mechanical finger with a rigid-flexible coupling structure and a driving method therefor. Background Art

[0002] With the increasing maturity of research fields such as motion mechanism design, new material science, and robot control algorithms, robots are playing an increasingly important role in application scenarios such as industrial production and daily housework services. As the end effector of a robot, a robot gripper directly undertakes the interaction and grasping functions of the robot, and its performance is crucial for the bearing capacity, practicality, and flexibility of the robot.

[0003] In daily housework service scenarios, the types, sizes, contour features, surface stiffness, and placement poses of objects to be grasped are diverse. Existing grippers still face challenges in achieving multi-mode and multi-pose grasping. In particular, when grasping different target objects, it is difficult to achieve stable grasping and safe interaction effects through adaptive conformal grasping, and there are also many deficiencies in the integrated design and compactness of functional components. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems and limitations existing in the existing design, the present invention proposes an adaptive grasping mechanical finger with a rigid-flexible coupling structure and a driving method therefor. By combining the two-end design of a multi-finger joint rigid-flexible coupling elastic finger and a parallel four-bar mechanism, it is possible to actively adjust the grasping size range for objects of different sizes and actively conform to objects with different contour features in daily housework service scenarios, thereby achieving stable grasping and safe interaction effects. The specific technical solutions are as follows: The present invention discloses an adaptive grasping mechanical finger with a rigid-flexible coupling structure, including a finger root base, a parallel four-bar mechanism, and a rigid-flexible coupling multi-finger joint elastic finger; the parallel four-bar mechanism is fixed on the finger root base through a drive shaft system and a rotating fixed shaft system structure, and its end is connected to the fixed base at the root of the rigid-flexible coupling multi-finger joint elastic finger, and is used to support the multi-finger joint elastic finger structure and adjust the grasping size and height; a drive gear set for two-way transmission and adaptive stepless adjustment of the two-way driving torque is installed in the finger root base, which can drive the parallel four-bar mechanism and the rigid-flexible coupling multi-finger joint elastic finger at the same time, and realize the coupling of the motions of the two parts of the structure.

[0005] Further, the base of the finger root is composed of a finger root frame for fixing each shafting component, a reduction drive motor fixed on the back of the base of the finger root, a mechanical differential bilateral shafting component for realizing bidirectional shunt of the motor driving torque, a bidirectional wire pulley shafting for driving a rigid-flexible coupled multi-finger joint elastic finger through a pull rope, an outer drive shafting, and an inner optical axis; wherein the finger root base frame is divided into a right-half structure and a left-half structure during manufacturing, that is, the right frame of the finger root base and the left frame of the finger root base are respectively manufactured by 3D printing using the FDM process, and after manufacturing and forming, the two frame structures are combined into one by bolt connection; the planetary gear reduction drive motor is composed of a DC constant-speed motor, a three-stage series planetary gear reducer, a reduction drive motor fixed frame, and a reduction drive motor output shaft, and the motor torque can be amplified through the planetary gear set to meet the torque requirement for the gripper to grasp and carry the target object.

[0006] Specifically, the planetary gear reduction drive motor is composed of a DC constant-speed motor with adjustable DC speed and a three-stage series planetary gear reducer arranged coaxially; this three-stage series planetary gear reducer is a general-purpose drive motor with a standard specification, and the selected model is XYT GA16Y-089-CE.

[0007] Further, the mechanical differential bilateral drive shafting is composed of a mechanical differential input shaft, a mechanical differential main reduction ratio gear, a planetary gear cage, a left output shaft of the differential, a right output shaft of the differential, a left bearing of the differential shafting, a right bearing of the differential shafting, a dynamic link end power output pinion, and a bidirectional wire pulley end power output pinion; the mechanical differential input shaft is coaxially connected to the output shaft of the reduction drive motor, and the mechanical differential main reduction ratio gear is driven to rotate through the mechanical differential input shaft, thereby driving the planetary gear cage fixedly connected to the mechanical differential main reduction ratio gear to rotate; the planetary gear cage is internally equipped with epicyclic planetary gears arranged perpendicular to the left output shaft and the right output shaft of the differential, and the driving torque is distributed to both sides by meshing with the gears on both output shafts; wherein the dynamic link end power output pinion drives the driving shafting of the active link of the parallel four-bar mechanism, and the bidirectional wire pulley end power output pinion drives the bidirectional wire pulley shafting.

[0008] Further, the driving torque is distributed to both sides by meshing with the gears at the ends of both output shafts. When the loads on both sides are equal, the epicyclic planetary gears are stationary relative to the epicyclic axis, and at this time, the output torques on both sides are equal; when one side is blocked during movement, the epicyclic planetary gears perform self-rotation movement around the epicyclic axis, thereby realizing stepless adjustment of the rotational speeds and driving torque distribution on both sides.

[0009] Furthermore, the driving shaft system of the parallel four-bar linkage mechanism consists of a driving link driving shaft, a large gear at the power input end of the driving link, a bearing at the right end of the driving shaft system of the driving link, and a bearing at the left end of the driving shaft system of the driving link; the two-way wire pulley shaft system consists of a main support shaft of the two-way wire pulley, a large gear at the power input end of the two-way wire pulley end, a bearing at the two-way wire pulley end, and a two-way wire pulley; the wire loop for driving the bi-directional bending of the rigid-flexible coupled multi-fingered elastic finger is wound in the wire groove of the two-way wire pulley. When the two-way wire pulley rotates, the length difference of the wires on the inner and outer sides can be changed to drive the bi-directional bending of the elastic finger structure.

[0010] Furthermore, the parallel four-bar linkage mechanism is composed of a driving link of the parallel four-bar linkage mechanism and a driven link of the parallel four-bar linkage mechanism; the driven link of the parallel four-bar linkage mechanism is integrally manufactured by 3D printing as a whole structure. The driving link of the parallel four-bar linkage mechanism is divided into two parts, namely, the right-side structure and the left-side structure of the driving link, and after manufacturing and forming, the left and right parts are joined together by bolt connection; the bottom of the driving link of the parallel four-bar linkage mechanism is connected to the driving shaft system component through a spline structure, and when the driving shaft rotates, the front and back swing of the parallel four-bar linkage mechanism can be realized.

[0011] Furthermore, the rigid-flexible coupled multi-fingered elastic finger has a three-joint structure, and its main body consists of a corrugated elastic joint of the rigid-flexible coupled multi-fingered elastic finger, a rigid finger abdomen back plate of the first rigid-flexible coupled multi-fingered elastic finger, a rigid finger abdomen back plate of the second rigid-flexible coupled multi-fingered elastic finger, a fixed base at the root of the multi-fingered elastic finger, an elastic silicone film at the end grasping contact surface, and an elastic silicone film at the middle grasping contact surface; among them, the corrugated elastic joint of the rigid-flexible coupled multi-fingered elastic finger consists of a rigid finger abdominal cavity body of the third finger joint of the multi-fingered elastic finger, a corrugated elastic joint structure of the second finger joint of the multi-fingered elastic finger, a rigid finger abdominal cavity body of the second finger joint of the multi-fingered elastic finger, a corrugated elastic joint structure of the first finger joint of the multi-fingered elastic finger, a rigid finger abdominal cavity body of the first finger joint of the multi-fingered elastic finger, a corrugated elastic joint structure of the third finger joint of the multi-fingered elastic finger, and a fixed finger joint structure at the root of the multi-fingered elastic finger; the rigid finger abdominal cavity body of the third finger joint of the multi-fingered elastic finger is integrally designed with a tip tweezing structure, which can realize the tip tweezing of small-size and thin-sheet target objects; the back of the rigid-flexible coupled multi-fingered elastic finger is fixed with a rigid finger abdomen back plate of the first rigid-flexible coupled multi-fingered elastic finger and a rigid finger abdomen back plate of the second rigid-flexible coupled multi-fingered elastic finger by screws; the root of the rigid-flexible coupled multi-fingered elastic finger is connected to the fixed base at the root of the multi-fingered elastic finger through an embedding structure, and is connected to the parallel four-bar linkage mechanism through the fixed base at the root of the multi-fingered elastic finger.

[0012] Furthermore, the multi-fingered elastic finger root fixing base is composed of a multi-fingered elastic finger root fixing base, a fixed-position bearing, and a multi-fingered elastic finger wire guiding pulley; the multi-fingered elastic finger root fixing base is a structure that fits and connects with the rigid-flexible coupled multi-fingered elastic finger root, the fixed-position bearing is the position where the end of the parallel four-bar linkage is fixedly connected to the multi-fingered elastic finger root fixing base, and the multi-fingered elastic finger wire guiding pulley is a structure for fixing and guiding the wire of the two-way wire-pulling mechanism; a terminal grasping contact surface elastic silicone film and a middle grasping contact surface elastic silicone film are sleeved and installed on the front surface of the rigid-flexible coupled multi-fingered elastic finger as the grasping contact surface structure, which can realize the grasping and fitting of target objects with different surface contour features and the safe interaction with objects with different surface stiffnesses.

[0013] The present invention also discloses a driving method for an adaptive grasping mechanical finger with a rigid-flexible coupling structure, which is characterized by including the following steps: S1. Start the conformable grasping work for the target object. Under the drive of the planetary gear reduction drive motor, the driving torque is input to the main reduction ratio gear of the mechanical differential through the output shaft of the reduction drive motor and the input shaft of the mechanical differential. The relative rotation of the epicyclic planetary gears around the epicyclic shaft realizes the stepless adjustment and distribution of the bilateral rotational speeds and driving torques. S2. In the bilateral drive shaft system of the mechanical differential, the left output shaft and the right output shaft of the differential realize the stepless adjustment and distribution of the bilateral driving torques and rotational speeds through the meshing of the end gears of the left and right output shafts with the epicyclic planetary gears. Through the driving pinions at the ends of the active links and the driving pinions at the ends of the two-way wire wheels, the two-way wire wheel shaft system and the active link drive shaft system of the parallel four-bar linkage are respectively driven to realize the stepless coupling drive of the parallel four-bar linkage and the rigid-flexible coupled multi-fingered elastic finger. S3. When performing conformable grasping on the target object, before the mechanical finger touches the outer surface of the target object, the swing resistance on one side of the parallel four-bar linkage is small. At this time, the output rotational speeds of the bilateral drive shaft system of the mechanical differential are all distributed to the two-way wire wheel shaft system side, so that the parallel four-bar linkage swings first to the size range of the grasping dimension of the target object; when the grasping contact surface touches the outer contour of the target object, the swing of the parallel four-bar linkage is blocked. At this time, the driving torques of the bilateral drive shaft system of the mechanical differential all flow to the active link drive shaft system side of the parallel four-bar linkage. S4. The bidirectional wire-pulling mechanism is driven by a bidirectional wire-pulling wheel. The circumferential surface of the wire-pulling wheel is designed with a wire-pulling groove with 2.5 turns in both directions, and the bidirectional driving of wire-pulling can be realized through the friction force on both sides in the groove. When grasping the target object, the bidirectional wire-pulling wheel tightens the inner wire of the rigid-flexible coupled multi-fingered elastic finger and relaxes the outer wire, driving the corrugated elastic joint structure of the second section, the corrugated elastic joint structure of the first section, and the corrugated elastic joint structure of the third section of the multi-fingered elastic finger to tighten inward, realizing the fitting of the outer contour features of the target object, so as to achieve stable conformable grasping. S5. After grasping the target object, the rear manipulator can achieve the displacement and placement of the target object through parallel movement. When placing the target object, the planetary gear reduction drive motor in the finger root base rotates in the reverse direction, driving the rigid-flexible coupled multi-fingered elastic finger to bend and relax in the reverse direction and the parallel four-bar mechanism to swing outward, realizing the placement of the target object.

[0014] The beneficial effects of the present invention are as follows: The present invention is a novel mechanical finger based on a two-stage multi-fingered rigid-flexible coupling structure, which can realize the self-adaptive stepless adjustment of the grasping size and height according to the size and contour features of the grasped target object, and the conformable fitting of the grasping contour. It can realize the stable conformable grasping of target objects with different types, different sizes, external contours, surface stiffnesses, and center-of-gravity distributions in different placement postures in daily home service scenarios. Description of the Drawings

[0015] Figure 1 It is a schematic diagram of the overall structure of a novel adaptive grasping mechanical finger with a rigid-flexible coupling structure according to an embodiment of the present invention; Figure 2 It is a schematic diagram of the structure of the finger root base integrating a planetary gear reduction motor and a bidirectional parallel drive shaft system according to an embodiment of the present invention; Figure 3 It is a schematic diagram of the structure of the parallel four-bar mechanism according to an embodiment of the present invention; Figure 4 It is a schematic diagram of the structure of the bidirectional parallel drive shaft system based on a mechanical differential according to an embodiment of the present invention; Figure 5 It is a schematic diagram of the structure of the rigid-flexible coupled multi-fingered elastic finger and its bending function according to an embodiment of the present invention; Reference numerals: 1000 - finger root base, 2000 - parallelogram linkage mechanism, 3000 - rigid-flexible coupled multi-fingered elastic finger; 1100 - finger root base frame, 1200 - planetary gear reduction drive motor, 1300 - mechanical differential bilateral drive shaft system, 1400 - bidirectional wire pulley shaft system, 1500 - parallelogram linkage mechanism active link drive shaft system, 1600 - parallelogram linkage mechanism driven link shaft system, 2100 - parallelogram linkage mechanism active link, 2200 - parallelogram linkage mechanism driven link, 3100 - corrugated elastic joint of rigid-flexible coupled multi-fingered elastic finger, 3200 - rigid finger abdomen back plate of the first rigid-flexible coupled multi-fingered elastic finger, 3300 - rigid finger abdomen back plate of the second rigid-flexible coupled multi-fingered elastic finger, 3400 - fixed base at the root of multi-fingered elastic finger, 3500 - elastic silicone film at the end grasping contact surface, 3600 - elastic silicone film at the middle grasping contact surface; 1110 - right frame of finger root base, 1120 - left frame of finger root base, 1210 - DC constant speed motor, 1220 - 3-stage series planetary gear reducer, 1230 - fixed frame of reduction drive motor, 1240 - output shaft of reduction drive motor, 1310 - input shaft of mechanical differential, 1320 - main reduction ratio gear of mechanical differential, 1330 - planetary gear cage, 1340 - left output shaft of differential, 1350 - right output shaft of differential, 1360 - left bearing of differential shaft system, 1370 - right bearing of differential shaft system, 1380 - small power output gear at the active link end, 1390 - small power output gear at the bidirectional wire pulley end, 1410 - main support shaft of bidirectional wire pulley, 1420 - large power input gear at the bidirectional wire pulley end, 1430 - bearing at the bidirectional wire pulley end, 1440 - bidirectional wire pulley, 1510 - active link drive shaft, 1520 - large power input gear at the active link power input end, 1530 - right end bearing of active link drive shaft system, 1540 - left end bearing of active link drive shaft system, 1610 - driven link support fixed shaft, 1620 - bearings at both ends of driven link support fixed shaft, 2110 - right structure of active link, 2120 - left structure of active link, 2200 - passive link, 3110 - rigid finger abdominal cavity body of the third section of multi-fingered elastic finger, 3120 - corrugated elastic joint structure of the second section of multi-fingered elastic finger, 3130 - rigid finger abdominal cavity body of the second section of multi-fingered elastic finger, 3140 - corrugated elastic joint structure of the first section of multi-fingered elastic finger, 3150 - rigid finger abdominal cavity body of the first section of multi-fingered elastic finger, 3160 - corrugated elastic joint structure of the third section of multi-fingered elastic finger, 3170 - fixed finger joint structure at the root of multi-fingered elastic finger, 3410 - fixed base at the root of multi-fingered elastic finger, 3420 - fixed bearing, 3430 - wire pulley for multi-fingered elastic finger wire guiding. Detailed implementation mode

[0016] In order to make the objectives, technical solutions, and technical effects of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings of the specification and embodiments.

[0017] In an embodiment, the present invention provides an adaptive grasping robotic finger with a rigid-flexible coupling structure, which combines a base 1000 at the finger root, a parallelogram linkage mechanism 2000 that can adaptively adjust the grasping size and height, and a multi-joint rigid-flexible coupling elastic finger 3000 that can conformally fit the surface of the target object. Through the bidirectional transmission of the driving mechanism in the base 1000 at the finger root, the parallelogram linkage mechanism 2000 and the multi-joint elastic finger can be coupled to deform and adjust their movements, so as to conformally fit the contour features of the target object to be grasped, thereby achieving stable grasping and safe interaction with different types of objects.

[0018] Specifically, as Figure 1 shown, the adaptive grasping robotic finger with a rigid-flexible coupling mainly consists of three main structures: a base 1000 at the finger root, a parallelogram linkage mechanism 2000, and a multi-joint rigid-flexible coupling elastic finger 3000. The parallelogram linkage mechanism 2000 is fixed to the base at the finger root through an outer drive shaft and an inner optical axis structure, and its end is connected to the fixed base at the root of the multi-joint rigid-flexible coupling elastic finger 3000, serving to support the structure of the multi-joint elastic finger and adjust the grasping size and height. A drive gear set that can perform bidirectional transmission and adaptively and steplessly adjust the bilateral driving torque is installed in the base 1000 at the finger root, which can simultaneously drive the parallelogram linkage mechanism 2000 and the multi-joint rigid-flexible coupling elastic finger 3000, and realize the coupling of the movements of the two parts of the structure.

[0019] As Figure 2As shown in the figure, for the convenience of manufacturing and assembly, the base of the finger root 1000 is composed of a finger root frame 1100 for fixing each shafting component, a reduction drive motor 1200 fixed on the back of the finger root base, a mechanical differential bilateral shafting component 1300 for realizing the two-way shunt of the motor driving torque, a two-way wire pulley shafting 1400 for driving the rigid-flexible coupled multi-finger joint elastic fingers through a pull rope, a parallel four-link mechanism active link drive shafting 1500, and a parallel four-link mechanism driven link shafting 1600; among them, the finger root base frame 1100 is divided into a right-half structure and a left-half structure during manufacturing, that is, the right frame 1110 of the finger root base and the left frame 1120 of the finger root base are respectively manufactured by 3D printing using the FDM process. After manufacturing and forming, the two frame structures are connected and integrated by bolts; the planetary gear reduction drive motor 1200 is composed of a DC constant-speed motor 1210, a three-stage series planetary gear reducer 1220, a reduction drive motor fixed frame 1230, and a reduction drive motor output shaft 1240. The motor torque can be amplified through the planetary gear set to meet the torque requirement for the gripper to grasp and carry the target object. Specifically, the planetary gear reduction drive motor 1200 is composed of a DC constant-speed motor 1210 with adjustable DC speed and a three-stage series planetary gear reducer 1220 arranged coaxially. The three-stage series planetary gear reducer 1220 is a general-purpose drive motor with a standard specification, and the selected model is XYT GA16Y-089-CE.

[0020] As Figure 2 and Figure 3As shown, the mechanical differential bilateral drive shaft system 1300 is composed of a mechanical differential input shaft 1310, a mechanical differential main reduction ratio gear 1320, a planetary gear cage 1330, a left output shaft 1340 of the differential, a right output shaft 1350 of the differential, a left bearing 1360 of the differential shaft system, a right bearing 1370 of the differential shaft system, a dynamic connecting rod end power output pinion 1380, and a two-way wire pulley end power output pinion 1390. The mechanical differential input shaft 1310 is coaxially connected to the output shaft 1240 of the reduction drive motor, and drives the mechanical differential main reduction ratio gear 1320 to rotate through the mechanical differential input shaft 1310, thereby driving the planetary gear cage 1330 fixedly connected to the mechanical differential main reduction ratio gear 1320 to rotate. Inside the planetary gear cage 1330, there are epicyclic planetary gears arranged perpendicular to the left output shaft 1340 and the right output shaft 1350 of the differential, and the driving torque is distributed to both sides by meshing with the gears at the ends of the two output shafts; when the loads on both sides are equal, the epicyclic planetary gears are stationary relative to the epicyclic shaft, and the output torques on both sides are equal at this time; when one side is blocked during movement, the epicyclic planetary gears perform self-rotation around the epicyclic shaft, thereby realizing stepless adjustment of the rotational speeds and driving torque distributions on both sides. Among them, the dynamic connecting rod end power output pinion 1380 drives the parallel four-bar mechanism active connecting rod drive shaft system 1500, and the two-way wire pulley end power output pinion 1390 drives the two-way wire pulley shaft system 1400. The parallel four-bar mechanism active connecting rod drive shaft system 1500 is composed of an active connecting rod drive shaft 1510, an active connecting rod power input end large gear 1520, a right end bearing 1530 of the active connecting rod drive shaft system, and a left end bearing 1540 of the active connecting rod drive shaft system; the two-way wire pulley shaft system 1400 is composed of a two-way wire pulley main support shaft 1410, a two-way wire pulley end power input large gear 1420, a two-way wire pulley end bearing 1430, and a two-way wire pulley 1440; the wire loop for driving the two-way bending of the flexible-rigid coupling multi-fingered elastic finger 3000 is wound in the wire groove of the two-way wire pulley 1440, and when the two-way wire pulley 1440 rotates, it can drive the elastic finger structure to bend bidirectionally by changing the wire length difference between the inner and outer sides.

[0021] As Figure 4As shown, the parallelogram linkage 2000 consists of a parallelogram linkage driving link 2100 and a parallelogram linkage driven link 2200. For the design consideration of the assembly of the shafting components, the parallelogram linkage driven link 2200 is integrally manufactured by 3D printing. The parallelogram linkage driving link 2100 is manufactured in two parts, namely the right side structure 2110 of the driving link and the left side structure 2120 of the driving link. After manufacturing and forming, the left and right parts are joined together by bolt connection. The bottom of the parallelogram linkage driving link 2100 is connected to the drive shafting components through a spline structure. When the drive shaft rotates, the front and back swing of the parallelogram linkage 2000 can be realized.

[0022] As Figure 5As shown, the rigid-flexible coupled multi-fingered elastic finger 3000 has a three-joint structure. Its main body consists of the corrugated elastic joint 3100 of the rigid-flexible coupled multi-fingered elastic finger, the first rigid finger abdomen back plate 3200 of the rigid-flexible coupled multi-fingered elastic finger, the second rigid finger abdomen back plate 3300 of the rigid-flexible coupled multi-fingered elastic finger, the root fixing base 3400 of the multi-fingered elastic finger, the elastic silicone film 3500 of the end grasping contact surface, and the elastic silicone film 3600 of the middle grasping contact surface. Among them, the corrugated elastic joint 3100 of the rigid-flexible coupled multi-fingered elastic finger is composed of the rigid finger abdominal cavity body 3110 of the third finger joint of the multi-fingered elastic finger, the corrugated elastic joint structure 3120 of the second finger joint of the multi-fingered elastic finger, the rigid finger abdominal cavity body 3130 of the second finger joint of the multi-fingered elastic finger, the corrugated elastic joint structure 3140 of the first finger joint of the multi-fingered elastic finger, the rigid finger abdominal cavity body 3150 of the first finger joint of the multi-fingered elastic finger, the corrugated elastic joint structure 3160 of the third finger joint of the multi-fingered elastic finger, and the root fixing finger joint structure 3170 of the multi-fingered elastic finger; the rigid finger abdominal cavity body 3110 of the third finger joint of the multi-fingered elastic finger is integrally designed with a tip tweezing structure, which can realize the tip tweezing of small-size and thin-sheet target objects. The back of the rigid-flexible coupled multi-fingered elastic finger 3000 is fixed with the first rigid finger abdomen back plate 3200 of the rigid-flexible coupled multi-fingered elastic finger and the second rigid finger abdomen back plate 3300 of the rigid-flexible coupled multi-fingered elastic finger by screws; the root of the rigid-flexible coupled multi-fingered elastic finger 3000 is connected to the root fixing base 3400 of the multi-fingered elastic finger through a fitting structure, and is connected to the parallel four-bar linkage 2000 through the root fixing base 3400 of the multi-fingered elastic finger. The root fixing base 3400 of the multi-fingered elastic finger consists of the root fixing base 3410 of the multi-fingered elastic finger, the fixing bearing 3420, and the wire guiding pulley 3430 of the multi-fingered elastic finger; the root fixing base 3410 of the multi-fingered elastic finger is a structure fitted and connected to the root of the rigid-flexible coupled multi-fingered elastic finger, the fixing bearing 3420 is the position where the end of the parallel four-bar linkage 2000 is fixedly connected to the root fixing base 3410 of the multi-fingered elastic finger, and the wire guiding pulley 3430 of the multi-fingered elastic finger is a structure for fixing and guiding the wire of the two-way wire pulling mechanism. The elastic silicone film 3500 of the end grasping contact surface and the elastic silicone film 3600 of the middle grasping contact surface are sleeved and installed on the front of the rigid-flexible coupled multi-fingered elastic finger 3000 as the grasping contact surface structure, which can realize the grasping and fitting of target objects with different surface contour features and the safe interaction with objects with different surface stiffnesses.

[0023] In the embodiment of the present invention, the two-section rigid-flexible coupled adaptive grasping mechanical finger can realize the conformable grasping of the external dimensions and external contour features of the grasped target object through the front-back swing of the parallel four-bar linkage 2000 and the front-back bending adjustment of the rigid-flexible coupled multi-fingered elastic finger 3000, such as Figure 5As shown on the right. The parallel four-bar linkage 2000 can adjust the grasping size and height by swinging back and forth, and the rigid-flexible coupled multi-fingered elastic fingers 3000 can achieve the fitting of the outer contour features of the target object and the effect of safe interaction by bending in different directions.

[0024] In summary, when the novel adaptive grasping robotic finger with a rigid-flexible coupling structure of the present invention starts to work, the planetary gear reduction drive motor 1200 in the base 1000 of the finger root drives the bidirectional transmission gear shaft system 1300-1600. Through the bidirectional torque shunting, the coupling drive of the parallel four-bar linkage 2000 and the cable mechanism of the rigid-flexible coupling multi-fingered elastic finger 3000 is realized, and the adaptation of the external dimension of the target object and the fitting of the contour features can be achieved in the form of bilateral stepless adjustment of the driving torque. The specific driving method steps for conformally grasping the target object are as follows: (1) Driven by the planetary gear reduction drive motor 1200, the driving torque is input to the main reduction ratio gear 1320 of the mechanical differential through the output shaft 1240 of the reduction drive motor and the input shaft 1310 of the mechanical differential. The relative rotation of the epicyclic planetary gear around the epicyclic shaft can realize the stepless adjustment and distribution of the bilateral rotational speed and driving torque; (2) In the bilateral drive shaft system 1300 of the mechanical differential, the left output shaft 1340 and the right output shaft 1350 of the differential realize the stepless adjustment and distribution of the bilateral driving torque and rotational speed through the meshing of the end gears of the left and right output shafts with the epicyclic planetary gear. Through the driving pinions 1380 at the active link ends and the driving pinions 1390 at the ends of the bidirectional cable wheels at both ends, the bidirectional cable wheel shaft system 1400 and the active link drive shaft system 1500 of the parallel four-bar linkage are respectively driven to realize the stepless coupling drive of the parallel four-bar linkage 2000 and the rigid-flexible coupling multi-fingered elastic finger 3000; (3) When conformally grasping the target object, before the robotic finger contacts the outer surface of the target object, the swing resistance on one side of the parallel four-bar linkage 2000 is small. At this time, the output rotational speed of the bilateral drive shaft system 1300 of the mechanical differential is unidirectionally distributed to one side of the bidirectional cable wheel shaft system 1400, so that the parallel four-bar linkage 2000 swings to the size range of the grasping dimension of the target object first; when the grasping contact surface contacts the outer contour of the target object, the swing of the parallel four-bar linkage 2000 is blocked. At this time, all the driving torque of the bilateral drive shaft system 1300 of the mechanical differential flows to one side of the active link drive shaft system 1500 of the parallel four-bar linkage; (4) The bidirectional cable mechanism is driven by the bidirectional cable wheel 1440. The circumferential surface of the cable wheel is designed with a bidirectional cable groove of 2.5 turns, and the bidirectional drive of the cable can be realized through the friction on both sides in the groove. When grasping the target object, the bidirectional cable wheel 1440 tightens the inner cable of the rigid-flexible coupling multi-fingered elastic finger 3000 and relaxes the outer cable, driving the second corrugated elastic joint structure 3120, the first corrugated elastic joint structure 3140 and the third corrugated elastic joint structure 3160 of the multi-fingered elastic finger to tighten inward, realizing the fitting of the outer contour features of the target object, so as to realize stable conformal grasping; (5) After grasping the target object, the rear robotic arm can realize the displacement and placement of the target object through parallel movement.When the target object is placed, the planetary gear reduction drive motor 1200 in the base 1000 of the finger root rotates in the reverse direction, driving the rigid-flexible coupled multi-fingered elastic finger 3000 to bend and relax in the reverse direction and the parallel four-bar linkage 2000 to swing outward to place the target object.

[0025] Due to the application of the embodiments of the present invention, compared with existing similar mechanical grippers, the present invention has the advantages of a larger range of grippable sizes and load-bearing weights, being able to achieve adaptive grasping for target objects with different sizes, different external contour features, and different surface stiffnesses, being able to conform to the surface of the target object to achieve safe interaction and improve grasping stability, etc. Especially for the problems of stable grasping, attitude manipulation, and displacement placement of various types of target objects in the daily home service scenario, the present invention shows applicability and functionality that exceed those of similar products.

[0026] In the structural design description of this patent application, the structural design described by taking the embodiment of the two-stage rigid-flexible coupled structure adaptive grasping mechanical finger based on the mechanical differential bilateral drive is for the convenience of describing the structural principle of the present invention and simplifying the description, rather than indicating or implying that the device referred to must have a specific quantity and orientation, work in a specific assembly structure and operation sequence, so it cannot be understood as a limitation to the present invention.

[0027] The above embodiments are only for explaining the technical concept and features of the present invention, and their purpose is to enable those familiar with this technology to understand the content of the present invention and implement it accordingly, and cannot be used to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. An adaptive grasping robotic finger with a rigid-flexible coupling structure, characterized in that It includes a base at the root of the finger (1000), a parallel four-bar linkage mechanism (2000), and a rigid-flexible coupled multi-fingered elastic finger (3000); the parallel four-bar linkage mechanism (2000) is fixed on the base at the root of the finger (1000) through a drive shaft system and a rotating fixed shaft system structure, and its end is connected to the fixed base at the root of the rigid-flexible coupled multi-fingered elastic finger (3000), which is used to support the multi-fingered elastic finger structure and adjust the grasping size and height; a drive gear set for bidirectional transmission and self-adaptive stepless adjustment of the bidirectional driving torque is installed in the base at the root of the finger (1000), which can drive the parallel four-bar linkage mechanism (2000) and the rigid-flexible coupled multi-fingered elastic finger (3000) simultaneously, and realize the coupling of the movements of the two parts of the structure.

2. The adaptive grasping robotic finger according to claim 1, wherein The base at the root of the finger (1000) is composed of a finger root frame (1100) for fixing each shaft system component, a reduction drive motor (1200) fixed on the back of the base at the root of the finger, a mechanical differential bilateral shaft system component (1300) for realizing the bidirectional shunt of the motor driving torque, a bidirectional wire pulley shaft system (1400) for driving the rigid-flexible coupled multi-fingered elastic finger through a pull rope, an outer drive shaft system (1500), and an inner optical axis (1600); among them, the finger root base frame (1100) is divided into a right-half structure and a left-half structure during manufacturing, that is, the right frame of the finger root base (1110) and the left frame of the finger root base (1120) are respectively manufactured by 3D printing using the FDM process. After manufacturing and forming, the two side frame structures are combined into one by bolt connection; the planetary gear reduction drive motor (1200) is composed of a DC constant-speed motor (1210), a 3-stage series planetary gear reducer (1220), a reduction drive motor fixed frame (1230), and a reduction drive motor output shaft (1240). The motor torque can be amplified through the planetary gear set to meet the torque requirement for the gripper to grasp and carry the target object.

3. The adaptive grasping robotic finger according to claim 2, wherein The planetary gear reduction drive motor (1200) is composed of a DC constant-speed motor (1210) with adjustable DC speed and a 3-stage series planetary gear reducer (1220) arranged coaxially; the 3-stage series planetary gear reducer (1220) is a standard specification general-purpose drive motor, and the selected model is XYT GA16Y-089-CE.

4. The adaptive grasping robotic finger according to claim 1, characterized in that The mechanical differential bilateral drive shaft system (1300) consists of a mechanical differential input shaft (1310), a mechanical differential main reduction ratio gear (1320), a planetary gear cage (1330), a differential left output shaft (1340), a differential right output shaft (1350), a differential shaft system left bearing (1360), a differential shaft system right bearing (1370), a moving link end power output pinion (1380), and a two-way wire pulley end power output pinion (1390); the mechanical differential input shaft (1310) is coaxially connected to the reduction drive motor output shaft (1240), and drives the mechanical differential main reduction ratio gear (1320) to rotate through the mechanical differential input shaft (1310), thereby driving the planetary gear cage (1330) fixedly connected to the mechanical differential main reduction ratio gear (1320) to rotate; the planetary gear cage (1330) is internally equipped with epicyclic planetary gears arranged perpendicular to the differential left output shaft (1340) and the differential right output shaft (1350), and distributes the driving torque to both sides by meshing with the output shaft gears on both sides; among them, the moving link end power output pinion (1380) drives the parallel four-link mechanism active link drive shaft system (1500), and the two-way wire pulley end power output pinion (1390) drives the two-way wire pulley shaft system (1400).

5. The adaptive grasping robotic finger according to claim 4, characterized in that, The driving torque is distributed to both sides by meshing with the end gears of the output shafts on both sides. When the loads on both sides are equal, the epicyclic planetary gears are stationary relative to the epicyclic shaft, and the output torques on both sides are equal at this time; when one side is blocked during movement, the epicyclic planetary gears perform self-rotation around the epicyclic shaft, thereby realizing stepless adjustment of the rotational speeds and driving torque distribution on both sides.

6. The adaptive grasping robotic finger according to claim 4, characterized in that, The parallel four-link mechanism active link drive shaft system (1500) consists of an active link drive shaft (1510), an active link power input end large gear (1520), a right end bearing of the active link drive shaft system (1530), and a left end bearing of the active link drive shaft system (1540); the two-way wire pulley shaft system (1400) consists of a two-way wire pulley main support shaft (1410), a two-way wire pulley end power input large gear (1420), a two-way wire pulley end bearing (1430), and a two-way wire pulley (1440); the wire loop for driving the two-way bending of the flexible-rigid coupling multi-fingered elastic finger (3000) is wound in the wire groove of the two-way wire pulley (1440), and when the two-way wire pulley (1440) rotates, it can drive the elastic finger structure to bend bidirectionally by changing the wire length difference between the inner and outer sides.

7. The adaptive grasping robotic finger according to claim 1, wherein The parallel four-bar linkage mechanism (2000) is composed of a driving link (2100) and a driven link (2200) of the parallel four-bar linkage mechanism. The driven link (2200) of the parallel four-bar linkage mechanism is integrally formed by 3D printing as an integral structure. The driving link (2100) of the parallel four-bar linkage mechanism is manufactured in two parts, namely, the right-side structure (2110) and the left-side structure (2120) of the driving link. After manufacturing and forming, the two parts are joined together by bolt connection. The bottom of the driving link (2100) of the parallel four-bar linkage mechanism is connected to the drive shaft system component through a spline structure. When the drive shaft rotates, the parallel four-bar linkage mechanism (2000) can swing back and forth.

8. The adaptive grasping robotic finger according to claim 1, wherein The rigid-flexible coupled multi-fingered elastic finger (3000) has a three-joint structure. Its main body is composed of a corrugated elastic joint (3100) of the rigid-flexible coupled multi-fingered elastic finger, a first rigid finger belly backplate (3200) of the rigid-flexible coupled multi-fingered elastic finger, a second rigid finger belly backplate (3300) of the rigid-flexible coupled multi-fingered elastic finger, a root fixing base (3400) of the multi-fingered elastic finger, an elastic silicone film (3500) at the end grasping contact surface, and an elastic silicone film (3600) at the middle grasping contact surface. Among them, the corrugated elastic joint (3100) of the rigid-flexible coupled multi-fingered elastic finger is composed of a third rigid finger abdominal cavity body (3110) of the multi-fingered elastic finger, a second corrugated elastic joint structure (3120) of the multi-fingered elastic finger, a second rigid finger abdominal cavity body (3130) of the multi-fingered elastic finger, a first corrugated elastic joint structure (3140) of the multi-fingered elastic finger, a first rigid finger abdominal cavity body (3150) of the multi-fingered elastic finger, a third corrugated elastic joint structure (3160) of the multi-fingered elastic finger, and a root fixing finger joint structure (3170) of the multi-fingered elastic finger. The third rigid finger abdominal cavity body (3110) of the multi-fingered elastic finger is integrally designed with a tip tweezer structure, which can realize the tip tweezer of small-size and thin-sheet target objects. The first rigid finger belly backplate (3200) and the second rigid finger belly backplate (3300) of the rigid-flexible coupled multi-fingered elastic finger are fixed on the back by screws. The root of the rigid-flexible coupled multi-fingered elastic finger (3000) is connected to the root fixing base (3400) of the multi-fingered elastic finger through a fitting structure, and is connected to the parallel four-bar linkage mechanism (2000) through the root fixing base (3400) of the multi-fingered elastic finger.

9. The adaptive grasping robotic finger according to claim 8, wherein The multi-jointed elastic finger root fixing base (3400) is composed of a multi-jointed elastic finger root fixing base (3410), a fixed position bearing (3420) and a multi-jointed elastic finger wire drawing guide wheel (3430); the multi-jointed elastic finger root fixing base (3410) is a structure that is connected and engaged with the rigid-flexible coupling multi-jointed elastic finger root, the fixed position bearing (3420) is a position where the end of the parallel four-bar linkage (2000) is connected and fixed to the multi-jointed elastic finger root fixing base (3410), and the multi-jointed elastic finger wire drawing guide wheel (3430) is a structure for fixing and guiding the wire drawing by a bidirectional wire drawing mechanism; the rigid-flexible coupling multi-jointed elastic finger (3000) is fitted with an end gripping contact surface elastic silicone film (3500) and a middle gripping contact surface elastic silicone film (3600) as a gripping contact surface structure on the front side, which can realize the gripping and fitting of target objects with different surface contour characteristics and the safe interaction of objects with different surface stiffness.

10. A driving method for an adaptive grasping robotic finger with a rigid-flexible coupling structure according to any one of claims 1-9, characterized in that, The steps include: S1. Start conformal grasping of the target object. Driven by the planetary gear reduction drive motor (1200), the driving torque is input to the mechanical differential main reduction ratio gear (1320) through the reduction drive motor output shaft (1240) and the mechanical differential input shaft (1310). The relative rotation of the epicyclic planetary gear around the epicyclic axis realizes stepless adjustment and distribution of bilateral rotation speed and driving torque. S2. In the mechanical differential bilateral transmission shaft system (1300), the left output shaft (1340) and the right output shaft (1350) of the differential are meshed with the left and right output shaft end gears and the epicyclic planetary gears to achieve stepless adjustment and distribution of bilateral driving torque and rotation speed. The active connecting rod end power output pinion (1380) and the two-way cable pulley end power output pinion (1390) at both ends are used to drive the two-way cable pulley shaft system (1400) and the parallel four-bar linkage active connecting rod driving shaft system (1500) respectively to achieve stepless coupling drive of the parallel four-bar linkage (2000) and the rigid-flexible coupling multi-joint elastic fingers (3000); S3. When conformally grasping the target object, before the mechanical finger contacts the outer surface of the target object, the swing resistance on one side of the parallel four-bar linkage (2000) is small. At this time, the output rotation speed of the mechanical differential double-sided transmission shaft system (1300) is all distributed to one side of the two-way pulley shaft system (1400), so that the parallel four-bar linkage (2000) first swings to the grasping size range of the target object; when the grasping contact surface contacts the outer contour of the target object, the swing of the parallel four-bar linkage (2000) is blocked. At this time, the driving torque of the mechanical differential double-sided transmission shaft system (1300) all flows to one side of the parallel four-bar linkage active link driving shaft system (1500); S4. The bidirectional wire-pulling mechanism is driven by a bidirectional wire-pulling wheel (1440). The circumferential surface of the wire-pulling wheel is designed with a wire-pulling groove with 2.5 turns in both directions, and the bidirectional drive of wire-pulling can be realized through the friction force on both sides in the groove. When grasping the target object, the bidirectional wire-pulling wheel (1440) tightens the inner wire of the rigid-flexible coupled multi-fingered elastic finger (3000) and relaxes the outer wire, driving the second corrugated elastic joint structure (3120), the first corrugated elastic joint structure (3140) and the third corrugated elastic joint structure (3160) of the multi-fingered elastic finger to tighten inward, realizing the fitting of the outer contour features of the target object, so as to achieve stable conformable grasping. S5. After grasping the target object, the rear manipulator can realize the displacement and placement of the target object through parallel movement. When placing the target object, the planetary gear reduction drive motor (1200) in the finger root base (1000) rotates reversely, driving the rigid-flexible coupled multi-fingered elastic finger (3000) to bend and relax reversely and the parallel four-bar mechanism (2000) to swing outward, realizing the placement of the target object.

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