An adaptive grasping mechanical finger with a rigid-flexible coupling structure and a driving method thereof

Abstract

The present invention discloses an adaptive grasping robot finger with a rigid-flexible coupling structure and a driving method thereof, comprising a finger root base, a parallelogram linkage, and a rigid-flexible coupling multi-joint elastic finger structure. The parallelogram linkage is fixed to a hole in the finger root base via a rotating shaft and a rolling bearing. The other end of the parallelogram linkage is fixed to the root base structure of the rigid-flexible coupling multi-joint elastic finger via a rolling bearing in the hole. The rigid-flexible coupling multi-joint elastic finger is connected to the rest of the robot finger structure via the root base. This novel robot finger can achieve adaptive and stepless adjustment of the grasping size and height according to the size and contour characteristics of the grasping target object, and conformally fit the grasping contour. It can achieve stable and fitting grasping of target objects of different types, sizes, contours, surface stiffness, and center of gravity distribution in different placement positions in daily home service scenarios.

Description

Technical Field

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

[0002] With the increasing maturity of research in areas such as motion mechanism design, novel materials science, and robotic control algorithms, robots are playing an increasingly important role in applications ranging from industrial production to daily household services. As the end-point of a robot's execution, the gripper directly handles interaction and grasping, and its performance is crucial to the robot's load capacity, practicality, and flexibility.

[0003] In daily home service scenarios, the types, sizes, contour features, surface stiffness and placement postures of the target objects to be grasped are diverse. Existing grippers still face challenges in achieving multi-mode and multi-posture grasping, especially when grasping different target objects. It is difficult to achieve stable grasping and safe interaction at the same time through adaptive conformal grasping. There are also many shortcomings in the integrated design and compactness of functional components. Summary of the Invention

[0004] To address the aforementioned technical issues and limitations of existing designs, the present invention proposes an adaptive gripping robot finger with a rigid-flexible coupling structure and its driving method. By combining a multi-joint rigid-flexible coupling elastic finger with a two-end parallelogram linkage, it can actively adjust the gripping size range for objects of different sizes in daily housekeeping service scenarios, and actively conform to objects with different contour features, thereby achieving stable gripping and safe interaction. The specific technical solution is as follows:

[0005] The present invention discloses an adaptive grasping mechanical finger with a rigid-flexible coupling structure, comprising a finger root base, a parallel four-bar linkage and a rigid-flexibly coupled multi-joint elastic finger; the parallel four-bar linkage is fixed to the finger root base through a driving shaft system and a rotating fixed shaft system structure, and its end is connected to the fixed base at the root of the rigid-flexibly coupled multi-joint elastic finger, for supporting the multi-joint elastic finger structure and adjusting the grasping size and height; a driving gear set with bidirectional transmission and adaptive stepless adjustment of the bidirectional driving torque is installed in the finger root base, which can simultaneously drive the parallel four-bar linkage and the rigid-flexibly coupled multi-joint elastic finger, and realize the coupling of the movements of the two structures.

[0006] Furthermore, the finger root base is composed of a finger root frame for fixing various shaft system components, a reduction drive motor fixed on the back of the finger root base, a mechanical differential bilateral shaft system component for realizing bidirectional diversion of the motor drive torque, a bidirectional pulley shaft system for driving the rigid-flexible coupled multi-joint elastic fingers through a pull rope, an outer drive shaft system 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 side frame of the finger root base and the left side frame of the finger root base are respectively manufactured by FDM process 3D printing, and after manufacturing and molding, the two side frame structures are combined into one by bolt connection; the planetary gear reduction drive motor is composed of a DC constant speed motor, a 3-stage series planetary gear reducer, a reduction drive motor fixing frame and a reduction drive motor output shaft. The motor torque can be amplified by the planetary gear set to meet the torque requirement of the gripper to grasp the target object.

[0007] Specifically, the planetary gear reduction drive motor consists of a DC constant speed motor with adjustable speed and a coaxially arranged 3-stage series planetary gear reducer; the 3-stage series planetary gear reducer is a universal drive motor with standard specifications, and the selected model is XYT GA16Y-089-CE.

[0008] Furthermore, the mechanical differential bilateral transmission shaft system is composed of a mechanical differential input shaft, a mechanical differential main reduction ratio gear, a planetary gear holder, a differential left output shaft, a differential right output shaft, a differential shaft system left bearing, a differential shaft system right bearing, a dynamic connecting rod end power output pinion and a bidirectional cable pulley end power output pinion; the mechanical differential input shaft is coaxially connected to the reduction drive motor output shaft, and the mechanical differential main reduction ratio gear is driven to rotate by the mechanical differential input shaft, thereby driving the planetary gear holder fixed to the mechanical differential main reduction ratio gear to rotate; the planetary gear holder is equipped with an epicyclic planetary gear arranged perpendicular to the differential left output shaft and the differential right output shaft, and distributes the driving torque to both sides by meshing with the output shaft gears on both sides; wherein the dynamic connecting rod end power output pinion drives the parallel four-bar linkage active connecting rod drive shaft system, and the bidirectional cable pulley end power output pinion drives the bidirectional cable pulley shaft system.

[0009] Furthermore, the driving torque is distributed to both sides by meshing with the gears at the ends of the output shafts on both sides. When the loads on both sides are equal, the epicyclic planetary gear is stationary relative to the epicyclic shaft, and the output torque on both sides is equal. When the movement of one side is blocked, the epicyclic planetary gear rotates around the epicyclic shaft, thereby achieving stepless adjustment of the speed and driving torque distribution on both sides.

[0010] Furthermore, the active connecting rod drive shaft system of the parallel four-bar linkage mechanism is composed of an active connecting rod drive shaft, a large gear at the power input end of the active connecting rod, a right end bearing of the active connecting rod drive shaft system and a left end bearing of the active connecting rod drive shaft system; the bidirectional wire pulling wheel shaft system is composed of a bidirectional wire pulling wheel main support shaft, a bidirectional wire pulling wheel end power input large gear, a bidirectional wire pulling wheel end bearing and a bidirectional wire pulling wheel; the wire pulling loop that drives the rigid-flexible coupled multi-joint elastic finger to bend in both directions is wound in the wire groove of the bidirectional wire pulling wheel. When the bidirectional wire pulling wheel rotates, the elastic finger structure can be driven to undergo bidirectional bending by changing the difference in wire length between the inner and outer sides.

[0011] Furthermore, the parallel four-bar linkage mechanism is composed of a parallel four-bar linkage active link and a parallel four-bar linkage driven link; the parallel four-bar linkage driven link is an integral structure manufactured by one-piece 3D printing, and the parallel four-bar linkage active link is divided into two parts: the right side structure of the active link and the left side structure of the active link. After manufacturing, the left and right parts are spliced ​​into one by bolt connection; the bottom of the parallel four-bar linkage active link is connected to the drive shaft system component through a spline structure, and the parallel four-bar linkage mechanism can realize the forward and backward swing of the parallel four-bar linkage when the drive shaft rotates.

[0012] Furthermore, the rigid-flexible coupled multi-joint elastic finger is a three-joint structure, and its main body is composed of a rigid-flexible coupled multi-joint elastic finger corrugated elastic joint, a first rigid-flexible coupled multi-joint elastic finger rigid finger palate back plate, a second rigid-flexible coupled multi-joint elastic finger rigid finger palate back plate, a multi-joint elastic finger root fixed base, an end gripping contact surface elastic silicone film and a middle gripping contact surface elastic silicone film; wherein the rigid-flexible coupled multi-joint elastic finger corrugated elastic joint is composed of a rigid finger palate cavity of the third section of the multi-joint elastic finger, a corrugated elastic joint structure of the second section of the multi-joint elastic finger, a rigid finger palate cavity of the second section of the multi-joint elastic finger, a corrugated elastic joint structure of the first section of the multi-joint elastic finger, The knuckle elastic finger is composed of a rigid finger pulp cavity of the first section, a corrugated elastic joint structure of the third section of the multi-knuckle elastic finger, and a fixed knuckle structure at the root of the multi-knuckle elastic finger; the rigid finger pulp cavity of the third section of the multi-knuckle elastic finger is integrated with a tip tweezers structure, which can realize the tip tweezers of small-sized and thin-sheet target objects; the back of the rigid-flexible coupled multi-knuckle elastic finger is fixed with a first rigid-flexible coupled multi-knuckle elastic finger rigid finger pulp back plate and a second rigid-flexible coupled multi-knuckle elastic finger rigid finger pulp back plate by screws; the root of the rigid-flexible coupled multi-knuckle elastic finger is connected to the multi-knuckle elastic finger root fixed base through a chimeric structure, and is connected to the parallel four-bar linkage mechanism through the multi-knuckle elastic finger root fixed base.

[0013] Furthermore, the multi-joint elastic finger root fixing base is composed of a multi-joint elastic finger root fixing base, a fixed position bearing and a multi-joint elastic finger pull wire guide wheel; the multi-joint elastic finger root fixing base is a structure that is interlocked and connected to the rigid-flexible coupling multi-joint elastic finger root, the fixed position bearing is a position where the end of the parallel four-bar linkage is connected to the multi-joint elastic finger root fixing base and fixed, and the multi-joint elastic finger pull wire guide wheel is a structure for fixing and guiding the pull wire of the bidirectional pull wire mechanism; the front of the rigid-flexible coupling multi-joint elastic finger is fitted with an elastic silicone film of the end grasping contact surface and an elastic silicone film of the middle grasping contact surface as a grasping contact surface structure, which can realize the grasping and fitting of target objects with different surface contour characteristics and the safe interaction of objects with different surface stiffness.

[0014] The present invention also discloses a driving method for an adaptive grasping mechanical finger of a rigid-flexible coupling structure, which is characterized by comprising the following steps:

[0015] S1. Start conformal grasping of the target object. Driven by the planetary gear reduction drive motor, the driving torque is input to the mechanical differential main reduction ratio gear through the reduction drive motor output shaft and the mechanical differential input shaft. The relative rotation of the epicyclic planetary gear around the epicyclic axis realizes stepless adjustment and distribution of bilateral rotation speed and driving torque.

[0016] S2. In the mechanical differential's bilateral drive shaft system, the left and right differential output shafts mesh with the epicyclic planetary gears at the ends of the left and right output shafts, achieving stepless adjustment and distribution of the bilateral drive torque and speed. The power output pinions at the active connecting rod end and the two-way cable pulley end drive the two-way cable pulley shaft system and the parallel four-bar linkage active connecting rod drive shaft system, respectively, to achieve stepless coupled drive of the parallel four-bar linkage and the rigid-flexible coupling multi-joint elastic fingers.

[0017] S3. 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 is small. At this time, the output speed of the mechanical differential's bilateral transmission shaft system is fully distributed to the bidirectional pulley shaft system, allowing the parallel four-bar linkage to swing to the grasping size range 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 is blocked. At this time, the driving torque of the mechanical differential's bilateral transmission shaft system all flows to the parallel four-bar linkage's active link drive shaft system.

[0018] 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 bidirectional 2.5-circle wire pulling groove, which can realize bidirectional driving of the wire pulling through the friction force on both sides of the groove. When grasping the target object, the bidirectional wire pulling wheel tightens the inner wire pulling wire and relaxes the outer wire pulling wire, driving the second section corrugated elastic joint structure of the multi-joint elastic finger, the first section corrugated elastic joint structure of the multi-joint elastic finger, and the third section corrugated elastic joint structure of the multi-joint elastic finger to tighten inward, so as to achieve the fit of the outer contour features of the target object, thereby realizing stable conformal grasping.

[0019] S5. After grabbing the target object, the rear-end robotic arm can achieve the displacement and placement of the target object through parallel movement; when the target object is placed, the planetary gear reduction drive motor in the base of the finger root rotates in the opposite direction, driving the rigid-flexible coupled multi-joint elastic finger to bend and relax in the opposite direction and the parallel four-bar linkage mechanism to swing outward to achieve the placement of the target object.

[0020] The beneficial effects of the present invention are as follows:

[0021] The present invention is a new type of robotic finger based on a two-stage multi-joint rigid-flexible coupling structure, which can realize adaptive and stepless adjustment of the grasping size and height and conformal fitting of the grasping contour according to the size and contour characteristics of the grasping target object. It can realize stable and fitting grasping of target objects of different types, sizes, contours, surface stiffness and center of gravity distribution in different placement positions in daily home service scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the overall structure of a new type of adaptive grasping mechanical finger with a rigid-flexible coupling structure according to an embodiment of the present invention;

[0023] Figure 2 Schematic diagram of the structure of the finger root base integrated with a planetary gear reduction motor and a bidirectional parallel drive shaft system in an embodiment of the present invention;

[0024] Figure 3 Schematic diagram of the structure of a parallel four-bar linkage mechanism in an embodiment of the present invention;

[0025] Figure 4 Schematic diagram of a bidirectional parallel drive shaft system structure based on a mechanical differential in an embodiment of the present invention;

[0026] Figure 5 Schematic diagram of a rigid-flexible coupled multi-joint elastic finger structure and its bending function in an embodiment of the present invention;

[0027] Figure numerals, 1000-finger root base, 2000-parallel four-bar linkage, 3000-rigid-flexible coupling multi-joint elastic finger; 1100-finger root base frame, 1200-planetary gear reduction drive motor, 1300-mechanical differential bilateral transmission shaft system, 1400-bidirectional pulley shaft system, 1500-parallel four-bar linkage active link drive shaft system, 1600-parallel four-bar linkage driven link shaft system, 2100-parallel four-bar linkage active link, 2200-parallel four-bar linkage driven link, 3100-rigid-flexible coupling multi-joint elastic finger corrugated elastic joint, 3200-first rigid-flexible coupling multi-joint elastic finger rigid finger web back plate, 3300-second rigid Soft-coupled multi-joint elastic finger rigid finger pad back plate, 3400-multi-joint elastic finger root fixed base, 3500-end gripping contact surface elastic silicone film, 3600-middle gripping contact surface elastic silicone film; 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-reduction drive motor fixing frame, 1240-reduction drive motor output shaft, 1310-mechanical differential input shaft, 1320-mechanical differential main reduction ratio gear, 1330-planetary gear cage, 1340-differential left output shaft, 1350-differential right output shaft , 1360-differential shaft left bearing, 1370-differential shaft right bearing, 1380-active connecting rod end power output pinion, 1390-bidirectional cable pulley end power output pinion, 1410-bidirectional cable pulley main support shaft, 1420-bidirectional cable pulley end power input large gear, 1430-bidirectional cable pulley end bearing, 1440-bidirectional cable pulley, 1510-active connecting rod drive shaft, 1520-active connecting rod power input end large gear, 1530-active connecting rod drive shaft right end bearing, 1540-active connecting rod drive shaft left end bearing, 1610-driven connecting rod support fixed shaft, 1620-driven connecting rod support fixed shaft bearings at both ends, 2110-active connecting rod Right side structure, 2120-active connecting rod left side structure, 2200-passive connecting rod, 3110-rigid finger pulp cavity of the third section of multi-jointed elastic finger, 3120-corrugated elastic joint structure of the second section of multi-jointed elastic finger, 3130-rigid finger pulp cavity of the second section of multi-jointed elastic finger, 3140-corrugated elastic joint structure of the first section of multi-jointed elastic finger, 3150-rigid finger pulp cavity of the first section of multi-jointed elastic finger, 3160-corrugated elastic joint structure of the third section of multi-jointed elastic finger, 3170-fixed finger joint structure at the root of multi-jointed elastic finger, 3410-fixed base at the root of multi-jointed elastic finger, 3420-fixed position bearing, 3430-wire guide wheel of multi-jointed elastic finger. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and technical effect of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0029] In an embodiment, the present invention proposes an adaptive grasping robotic finger with a rigid-flexible coupling structure, which combines a finger root base 1000, a parallel four-bar linkage 2000 that can adaptively adjust the grasping size and grasping height, and a multi-joint rigid-flexible coupled elastic finger 3000 that can conformally fit the surface of the target object. The parallel four-bar linkage 2000 and the multi-joint elastic finger can undergo coupled deformation and adjustment movements through the bidirectional transmission of the driving mechanism in the finger root base 1000, thereby achieving conformal fitting to the contour features of the target object to be grasped, thereby realizing stable grasping and safe interaction of different types of objects.

[0030] Specifically, such as Figure 1 As shown, the rigid-flexible coupled adaptive grasping mechanical finger mainly consists of three main structures: the finger root base 1000, the parallel four-bar linkage 2000 and the rigid-flexible coupled multi-joint elastic finger 3000. The parallel four-bar linkage 2000 is fixed to the finger root base through an outer drive shaft and an inner optical axis structure. Its end is connected to the fixed base at the root of the rigid-flexible coupled multi-joint elastic finger 3000, playing the role of supporting the multi-joint elastic finger structure and adjusting the grasping size and height. A driving gear set that can transmit in both directions and adaptively and steplessly adjust the bilateral driving torque is installed in the finger root base 1000. It can simultaneously drive the parallel four-bar linkage 2000 and the rigid-flexible coupled multi-joint elastic finger 3000, and realize the coupling of the movement of the two structures.

[0031] like Figure 2As shown, in order to facilitate manufacturing and assembly, the finger root base 1000 is composed of a finger root frame 1100 for fixing various shaft system components, a reduction drive motor 1200 fixed to the back of the finger root base, a mechanical differential bilateral shaft system component 1300 for realizing bidirectional diversion of the motor drive torque, a bidirectional pulley shaft system 1400 for driving the rigid-flexible coupled multi-joint elastic finger through a pull rope, a parallel four-bar linkage active link drive shaft system 1500 and a parallel four-bar linkage driven link shaft system 1600; wherein the finger root base frame 1100 is divided into a right half structure and a left half structure during manufacturing, that is, the finger root base right side frame 1110 The left frame 1120 of the finger root base is manufactured by 3D printing using the FDM process. After manufacturing, the two side frame structures are connected by bolts to form a whole. The planetary gear reduction drive motor 1200 consists of a DC constant speed motor 1210, a three-stage series planetary gear reducer 1220, a reduction drive motor fixing frame 1230 and a reduction drive motor output shaft 1240. The planetary gear set can amplify the motor torque to meet the torque requirements of the gripper to grasp the target object. Specifically, the planetary gear reduction drive motor 1200 consists of a DC constant speed motor 1210 with adjustable DC speed and a coaxially arranged three-stage series planetary gear reducer 1220. The three-stage series planetary gear reducer 1220 is a standard general-purpose drive motor with the model number XYT GA16Y-089-CE.

[0032] like Figure 2 and Figure 3As shown, the mechanical differential bilateral drive shaft system 1300 consists of a mechanical differential input shaft 1310, a mechanical differential final reduction ratio gear 1320, a planetary gear holder 1330, a left differential output shaft 1340, a right differential output shaft 1350, a left differential shaft system bearing 1360, a right differential shaft system bearing 1370, a dynamic connecting rod end power output pinion 1380, and a bidirectional cable pulley end power output pinion 1390. The mechanical differential input shaft 1310 is coaxially connected to the reduction drive motor output shaft 1240. The mechanical differential input shaft 1310 drives the mechanical differential final reduction ratio gear 1320 to rotate, thereby driving the planetary gear holder 1330 fixed to the mechanical differential final reduction ratio gear 1320 to rotate. Inside the planetary gear holder 1330, epicyclic planetary gears are mounted perpendicular to the left and right differential output shafts 1340 and 1350. These gears mesh with the gears at the ends of the output shafts on both sides to distribute the drive torque. When the load on both sides is equal, the epicyclic planetary gears remain stationary relative to the epicyclic shafts, resulting in equal output torque on both sides. When the motion of one side is blocked, the epicyclic planetary gears rotate around the epicyclic shaft, achieving stepless adjustment of the speed and drive torque distribution between the two sides. The power output pinion 1380 at the moving connecting rod end drives the parallel four-bar linkage active connecting rod drive shaft system 1500, while the power output pinion 1390 at the bidirectional cable pulley end drives the bidirectional cable pulley shaft system 1400. The active connecting rod drive shaft system 1500 of the parallel four-bar linkage mechanism is composed of an active connecting rod drive shaft 1510, a large gear 1520 at the power input end of the active connecting rod, 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 bidirectional wire pulling wheel shaft system 1400 is composed of a bidirectional wire pulling wheel main support shaft 1410, a bidirectional wire pulling wheel end power input large gear 1420, a bidirectional wire pulling wheel end bearing 1430 and a bidirectional wire pulling wheel 1440; the wire pulling loop that drives the rigid-flexible coupled multi-joint elastic finger 3000 to bend in both directions is wound in the wire groove of the bidirectional wire pulling wheel 1440. When the bidirectional wire pulling wheel 1440 rotates, the elastic finger structure can be driven to undergo bidirectional bending by changing the difference in wire length between the inner and outer sides.

[0033] like Figure 4As shown, the parallelogram linkage 2000 consists of a parallelogram active link 2100 and a parallelogram passive link 2200. To facilitate the assembly of shaft components, the passive link 2200 is manufactured in one piece via 3D printing. The active link 2100 is manufactured in two parts: a right-side active link structure 2110 and a left-side active link structure 2120. After manufacturing, the two parts are bolted together. The bottom of the active link 2100 is connected to the drive shaft components via a spline structure, enabling the parallelogram linkage 2000 to swing back and forth when the drive shaft rotates.

[0034] like Figure 5As shown, the rigid-flexible coupled multi-joint elastic finger 3000 is a three-joint structure, and its main body consists of a rigid-flexible coupled multi-joint elastic finger corrugated elastic joint 3100, a first rigid-flexible coupled multi-joint elastic finger rigid finger pad back plate 3200, a second rigid-flexible coupled multi-joint elastic finger rigid finger pad back plate 3300, a multi-joint elastic finger root fixed base 3400, an end gripping contact surface elastic silicone film 3500 and a middle gripping contact surface elastic silicone film 3600. The rigid-flexible coupled multi-joint elastic finger corrugated elastic joint 3100 is composed of a rigid finger palate cavity 3110 of the third section of the multi-joint elastic finger, a corrugated elastic joint structure 3120 of the second section of the multi-joint elastic finger, a rigid finger palate cavity 3130 of the second section of the multi-joint elastic finger, a corrugated elastic joint structure 3140 of the first section of the multi-joint elastic finger, a rigid finger palate cavity 3150 of the first section of the multi-joint elastic finger, a corrugated elastic joint structure 3160 of the third section of the multi-joint elastic finger and a fixed finger joint structure 3170 at the root of the multi-joint elastic finger; the rigid finger palate cavity 3110 of the third section of the multi-joint elastic finger is integrated with a tip tweezers structure, which can realize the tip tweezers for small-sized and thin-sheet target objects. The back of the rigid-flexible coupling multi-joint elastic finger 3000 is fixed with a first rigid-flexible coupling multi-joint elastic finger rigid finger pad back plate 3200 and a second rigid-flexible coupling multi-joint elastic finger rigid finger pad back plate 3300 by screws; the root of the rigid-flexible coupling multi-joint elastic finger 3000 is connected to the multi-joint elastic finger root fixed base 3400 through a chimeric structure, and is connected to the parallel four-bar linkage mechanism 2000 through the multi-joint elastic finger root fixed base 3400. The multi-jointed elastic finger root fixed base 3400 consists of a multi-jointed elastic finger root fixed base 3410, a fixed bearing 3420, and a multi-jointed elastic finger wire guide pulley 3430. The multi-jointed elastic finger root fixed base 3410 is a structure that interlocks and connects with the rigid-flexible coupled multi-jointed elastic finger root. The fixed bearing 3420 is the location where the end of the parallel four-bar linkage 2000 is connected to the multi-jointed elastic finger root fixed base 3410 and fixed. The multi-jointed elastic finger wire guide pulley 3430 is a structure that fixes and guides the wires in the bidirectional wire pulling mechanism. The front of the rigid-flexible coupled multi-jointed elastic finger 3000 is fitted with an elastic silicone film 3500 for the end gripping contact surface and an elastic silicone film 3600 for the middle gripping contact surface, which serve as the gripping contact surface structure. This allows for the gripping and fitting of objects with different surface contours and safe interaction with objects of varying surface stiffness.

[0035] The dual-stage rigid-flexible coupling adaptive grasping robot finger in the embodiment of the present invention can achieve conformal grasping of the external dimensions and external contour features of the grasping target object through the forward and backward swinging of the parallel four-bar linkage mechanism 2000 and the forward and backward bending adjustment of the rigid-flexible coupling multi-joint 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-joint elastic finger 3000 can adapt to the outer contour features of the target object and achieve safe interaction by bending in different directions.

[0036] In summary, when the new adaptive grasping mechanical finger with rigid-flexible coupling structure described in the present invention starts working, the planetary gear reduction drive motor 1200 in the finger root base 1000 drives the gear shaft system 1300~1600 with bidirectional transmission, and the coupling drive of the parallel four-bar linkage 2000 and the rigid-flexible coupling multi-joint elastic finger 3000 pulling mechanism is realized through the bidirectional diversion of torque, and the adaptation of the target object's external dimensions and the fitting of its contour features can be achieved through the form of bilateral stepless adjustment of the driving torque. The specific driving method steps for conformal grasping of target objects are as follows: (1) Under the drive of 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, and the relative rotation of the epicyclic planetary gear around the epicyclic axis can realize stepless adjustment and distribution of bilateral rotation speed and driving torque; (2) In the mechanical differential bilateral transmission shaft system 1300, the differential left output shaft 1340 and the differential right output shaft 1350 are engaged with the epicyclic planetary gear through the left and right output shaft end gears to realize stepless adjustment and distribution of bilateral driving torque and speed, and the two-way pulley shaft system 1400 and the parallel four-bar mechanism active connecting rod driving shaft system 1500 are driven respectively through the active connecting rod end power output pinion 1380 and the two-way pulley end power output pinion 1390 at both ends to realize the parallel four-bar linkage. (3) When the target object is conformally grasped, 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 speed of the mechanical differential bilateral transmission shaft system 1300 is unidirectionally distributed to the two-way wire pulling wheel shaft system 1400, so that the parallel four-bar linkage 2000 swings to the grasping size range 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, the driving torque of the mechanical differential bilateral transmission shaft system 1300 all flows to the active link driving shaft system 1500 of the parallel four-bar linkage; (4) The two-way wire pulling mechanism is driven by the two-way wire pulling wheel 1440. The circumferential surface of the wire pulling wheel is designed with a two-way 2.5-circle wire pulling groove, which can realize the two-way driving of the wire pulling through the friction force on both sides of the groove. When grasping the target object, the bidirectional wire pulley 1440 tightens the inner wire of the rigid-flexible coupled multi-joint elastic finger 3000 and relaxes the outer wire, driving the second section corrugated elastic joint structure 3120 of the multi-joint elastic finger, the first section corrugated elastic joint structure 3140 of the multi-joint elastic finger, and the third section corrugated elastic joint structure 3160 of the multi-joint elastic finger to tighten inward, thereby achieving the fit of the outer contour features of the target object, thereby achieving stable conformal grasping; (5) After grasping the target object, the rear-end robotic arm can achieve 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 finger root base 1000 rotates in the reverse direction, driving the rigid-flexible coupled multi-joint elastic finger 3000 to bend and relax in the reverse direction and the parallel four-bar linkage 2000 to swing outward, thereby achieving the placement of the target object.

[0037] Due to the application of the above-mentioned embodiments of the present invention, the present invention has a larger grasping size range and load-bearing weight range than existing similar mechanical grippers, can achieve adaptive grasping for target objects of different sizes, different external contour features and different surface stiffness, can conform to the surface of the target object to achieve safe interaction and improve grasping stability, etc., especially for the problems of stable grasping, posture manipulation and shift placement of various types of target objects in daily home service scenarios, the present invention has demonstrated applicability and functionality that surpasses similar products.

[0038] In the structural design description of the patent application of the present invention, the structural design is illustrated by using the embodiment of the two-stage rigid-flexible coupling structure adaptive grasping robot finger based on the mechanical differential bilateral transmission. This is for the convenience of describing the structural principles of the present invention and simplifying the description, rather than indicating or implying that the device referred to must have a specific number and orientation, and work with a specific assembly structure and operating sequence. Therefore, it cannot be understood as a limitation of the present invention.

[0039] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. An adaptive grasping robot finger with a rigid-flexible coupling structure, characterized in that: The invention comprises a finger base base (1000), a parallel four-bar linkage (2000) and a rigid-flexible coupling multi-joint elastic finger (3000); the parallel four-bar linkage (2000) is fixed on the finger base base (1000) through a driving 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-joint elastic finger (3000), and is used to support the multi-joint elastic finger structure and adjust the grasping size and height; a driving gear set with bidirectional transmission and adaptive stepless adjustment of bidirectional driving torque is installed in the finger base base (1000), which can simultaneously drive the parallel four-bar linkage (2000) and the rigid-flexible coupling multi-joint elastic finger (3000) and realize the coupling of the movement of the two parts of the structure; the finger base base The base (1000) is composed of a finger root frame (1100) for fixing various shaft system components, a reduction drive motor (1200) fixed to the back of the finger root base, a mechanical differential bilateral transmission shaft system (1300) for realizing bidirectional diversion of the motor drive torque, a bidirectional pulley shaft system (1400) for driving the rigid-flexible coupled multi-joint elastic fingers through a pull rope, an outer drive shaft system (1500) and an inner optical axis (1600); wherein the finger root base frame (1100) is divided into a right half structure and a left half structure during manufacturing, that is, the finger root base right side frame (1110) and the finger root base left side frame (1120) are respectively manufactured by FDM process 3D printing, and after manufacturing and forming, the frame structures on both sides 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 fixing frame (1230), and a reduction drive motor output shaft (1240). The motor torque can be amplified by the planetary gear set to meet the torque requirement of the gripper to grasp the target object. The mechanical differential bilateral transmission shaft system (1300) is composed of a mechanical differential input shaft (1310), a mechanical differential main reduction ratio gear (1320), a planetary gear holder (1330), a differential left output shaft (1340), a differential right output shaft (1350), a differential shaft system left bearing (1360), and a differential shaft system right bearing (1370). , a power output pinion (1380) at the moving connecting rod end and a power output pinion (1390) at the bidirectional pulling wheel end; a mechanical differential input shaft (1310) is coaxially connected to the reduction drive motor output shaft (1240), and the mechanical differential main reduction ratio gear (1320) is driven to rotate by the mechanical differential input shaft (1310), thereby driving the planetary gear holder (1330) fixedly connected to the mechanical differential main reduction ratio gear (1320) to rotate; the planetary gear holder (1330) is internally equipped with an epicyclic planetary gear arranged perpendicularly 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;The power output pinion (1380) at the moving connecting rod end drives the parallel four-bar linkage active connecting rod drive shaft system (1500), and the power output pinion (1390) at the two-way wire pulling wheel end drives the two-way wire pulling wheel shaft system (1400).

2. The adaptive grasping robot finger according to claim 1, characterized in that: The planetary gear reduction drive motor (1200) is composed of a DC constant speed motor (1210) with adjustable DC speed and a coaxially arranged three-stage series planetary gear reducer (1220).

3. The adaptive grasping robot finger according to claim 1, characterized in that: The driving torque is distributed to both sides by meshing with the gears at the ends of the output shafts on both sides. When the load on both sides is equal, the epicyclic planetary gear is stationary relative to the epicyclic shaft, and the output torque on both sides is equal. When the movement of one side is blocked, the epicyclic planetary gear rotates around the epicyclic shaft, thereby achieving stepless adjustment of the speed and driving torque distribution on both sides.

4. The adaptive grasping robot finger according to claim 1, characterized in that: The parallel four-bar linkage active link drive shaft system (1500) is composed of an active link drive shaft (1510), an active link power input end gear (1520), an active link drive shaft system right end bearing (1530) and an active link drive shaft system left end bearing (1540); the bidirectional wire pulling wheel shaft system (1400) is composed of a bidirectional wire pulling wheel main support shaft (1410), a bidirectional wire pulling wheel end power input gear (1420), a bidirectional wire pulling wheel end bearing (1430) and a bidirectional wire pulling wheel (1440); the wire pulling loop that drives the rigid-flexible coupling multi-joint elastic finger (3000) to bend in both directions is wound in the wire groove of the bidirectional wire pulling wheel (1440); when the bidirectional wire pulling wheel (1440) rotates, the elastic finger structure can be driven to bend in both directions by changing the wire length difference between the inner and outer sides.

5. The adaptive grasping robot finger according to claim 1, characterized in that: The parallel four-bar linkage (2000) is composed of a parallel four-bar linkage active link (2100) and a parallel four-bar linkage driven link (2200); the parallel four-bar linkage driven link (2200) is an integral structure manufactured by 3D printing, and the parallel four-bar linkage active link (2100) is divided into two parts: a right side structure (2110) of the active link and a left side structure (2120) of the active link. After manufacturing, the left and right parts are spliced ​​into one by bolt connection; the bottom of the parallel four-bar linkage active link (2100) is connected to the drive shaft system component through a spline structure, and the parallel four-bar linkage (2000) can realize the forward and backward swing of the parallel four-bar linkage when the drive shaft rotates.

6. The adaptive grasping robot finger according to claim 1, characterized in that: The rigid-flexible coupling multi-joint elastic finger (3000) is a three-joint structure, and its main body consists of a rigid-flexible coupling multi-joint elastic finger corrugated elastic joint (3100), a first rigid-flexible coupling multi-joint elastic finger rigid finger palate back plate (3200), a second rigid-flexible coupling multi-joint elastic finger rigid finger palate back plate (3300), a multi-joint elastic finger root fixed base (3400), an end gripping contact surface elastic silicone film (3500) and a middle gripping contact surface elastic silicone film (3600); wherein the rigid-flexible coupling multi-joint elastic finger corrugated elastic joint (3100) consists of a multi-joint elastic finger third section rigid finger palate cavity (3110), a multi-joint elastic finger second section corrugated elastic joint structure (3120), a multi-joint elastic finger second section rigid finger palate cavity (3130), a multi-joint elastic finger first section corrugated elastic joint structure (3140), The multi-joint elastic finger is composed of a rigid finger pulp cavity (3150) of the first section, a corrugated elastic joint structure (3160) of the third section of the multi-joint elastic finger, and a fixed finger pulp structure (3170) at the root of the multi-joint elastic finger; the rigid finger pulp cavity (3110) of the third section of the multi-joint elastic finger is integrated with a tip tweezers structure, which can realize the tip tweezers of small-sized and thin-sheet target objects; the back of the rigid-flexible coupling multi-joint elastic finger (3000) is fixed with a first rigid-flexible coupling multi-joint elastic finger rigid finger pulp back plate (3200) and a second rigid-flexible coupling multi-joint elastic finger rigid finger pulp back plate (3300) by screws; the root of the rigid-flexible coupling multi-joint elastic finger (3000) is connected to the multi-joint elastic finger root fixed base (3400) through a chimeric structure, and is connected to the parallel four-bar linkage (2000) through the multi-joint elastic finger root fixed base (3400).

7. The adaptive grasping robot finger according to claim 6, characterized in that: The multi-joint elastic finger root fixed base (3400) is composed of a multi-joint elastic finger root fixed base (3410), a fixed position bearing (3420) and a multi-joint elastic finger wire pulling guide wheel (3430); the multi-joint elastic finger root fixed base (3410) is a structure that is connected and engaged with the rigid-flexible coupling multi-joint 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-joint elastic finger root fixed base (3410), and the multi-joint elastic finger wire pulling guide wheel (3430) is a structure for fixing and guiding the wire pulling mechanism in a bidirectional manner; the rigid-flexible coupling multi-joint 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 features and the safe interaction of objects with different surface stiffness.

8. A driving method for an adaptive grasping robot finger of a rigid-flexible coupling structure according to any one of claims 1 to 7, 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 differential output shaft (1340) and the right differential output shaft (1350) 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 speed. The active connecting rod end power output pinion (1380) and the two-way cable pulley end power output pinion (1390) at both ends respectively drive the two-way cable pulley shaft system (1400) and the parallel four-bar linkage active connecting rod drive shaft system (1500) to achieve stepless coupling drive of the parallel four-bar linkage (2000) and the rigid-flexible coupling multi-joint elastic finger (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 speed of the mechanical differential bilateral transmission shaft system (1300) is all distributed to the bidirectional wire 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 bilateral transmission shaft system (1300) all flows to the parallel four-bar linkage active link drive 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 bidirectional 2.5-circle wire pulling groove, which can realize bidirectional driving of the wire pulling through the friction force on both sides of the groove. When grasping the target object, the bidirectional wire pulling wheel (1440) tightens the inner wire pulling wire of the rigid-flexible coupled multi-joint elastic finger (3000) and relaxes the outer wire pulling wire, driving the second section corrugated elastic joint structure (3120) of the multi-joint elastic finger, the first section corrugated elastic joint structure (3140) of the multi-joint elastic finger, and the third section corrugated elastic joint structure (3160) of the multi-joint elastic finger to tighten inward, thereby achieving the fit of the outer contour features of the target object, thereby achieving stable conformal grasping. S5. After grabbing the target object, the rear-end robotic arm can achieve 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 finger root base (1000) rotates in the reverse direction, driving the rigid-flexible coupled multi-joint elastic finger (3000) to bend and relax in the reverse direction and the parallel four-bar linkage (2000) to swing outward, thereby achieving the placement of the target object.

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