A cable-driven bionic soft fruit and vegetable harvesting manipulator

Abstract

The present invention discloses a cable-driven bionic soft fruit and vegetable harvesting manipulator, belonging to the field of soft picking manipulators, which includes a gripper driving mechanism, a mechanical gripper, an inner cable and an outer cable; the mechanical gripper includes a plurality of bionic fingers fixedly installed at the bottom of the lower flange, and the bionic fingers can only bend in the radial inner and outer directions of the lower flange; the inner and outer cables respectively penetrate the inner and outer sides of the bionic fingers. In the free state, the inner cable and the outer cable are not stressed, and the bionic fingers hang down naturally; under the action of the driving mechanism, when the inner cable is slack and the outer cable is tensioned, the bionic fingers bend radially outward along the lower flange, and the bionic soft fruit and vegetable harvesting manipulator opens; when the inner cable is tensioned and the outer cable is slack, the bionic fingers bend radially inward along the lower flange, and the bionic soft fruit and vegetable harvesting manipulator closes. The present invention has the advantages of multiple finger joints, structural flexibility, simple control, dexterity, embeddability, strong stiffness, etc., and overcomes the problems of complex power drive and insufficient rigidity of traditional manipulators.

Description

Technical Field

[0001] The present invention relates to the technical field of soft robots, particularly to the field of soft fruit and vegetable harvesting manipulators. Specifically, it is a cable-driven bionic soft fruit and vegetable harvesting manipulator, which is based on the structure of human fingers and has good stiffness, compliance, and grasping ability. Background Art

[0002] Manually performing fruit and vegetable harvesting tasks is time-consuming and laborious. To improve the efficiency of fruit and vegetable harvesting, scholars have developed various fruit and vegetable harvesting manipulators. However, most of the existing fruit and vegetable harvesting manipulators are rigid structures, and this kind of rigid structure is very easy to damage the fruits, resulting in a decline in the taste of the fruits. Soft materials are flexible materials with a Young's modulus similar to that of human fingers. Currently, mechanical claws made of soft materials can adapt to the shape of fruits and vegetables for grasping without damaging the fruits.

[0003] Chinese Patent CN201910452228.7 discloses a fruit picking mechanical device based on pneumatic flexible picking, which consists of a base, a large arm, a small arm, a wrist joint, soft mechanical fingers, an electric telescopic rod, a telescopic soft conveying pipeline, and a fruit collection box. It adopts six-finger pneumatic flexible wrapping picking, driven by air pressure, and can achieve non-destructive picking of various fruits. This picking mechanical device realizes the 360-degree rotation of the large arm through the drive of the base motor and gear transmission, drives the small arm to pitch through the electric telescopic rod, realizes the micro-rotation of the manipulator through the drive of the motor in the wrist joint and gear transmission, so that the soft mechanical fingers reach the appropriate picking position; uses an air pressure pump to drive the soft mechanical fingers to open and close to wrap the fruit, and then uses the pitch of the small arm to drive the rigid part of the manipulator to complete the separation of the fruit from the branch; the separated fruit is directly transported to the fruit collection box through the telescopic soft pipeline to complete a complete picking process.

[0004] Chinese Patent CN202010667378.2 discloses a soft picking manipulator, including a pneumatic finger cylinder, the pneumatic finger cylinder includes two rotating and extending ends; a support frame, the lower end of the support frame is fixedly connected to the rotating and extending ends of the pneumatic finger cylinder; a soft grasping member, the soft grasping member is fixedly connected to the upper end of the support frame; a gas charging and discharging assembly, the gas charging and discharging assembly inflates or deflates the soft grasping member; after the gas charging and discharging assembly inflates the soft grasping member, the soft grasping member bends, and after the gas charging and discharging assembly deflates, the soft grasping member restores. It solves the problem that most common strawberry picking machines mostly adopt the form of cutting the strawberry stalks for picking, the picking intensity is improved, but the remaining stalks seriously damage the epidermis of other strawberries in the strawberry packing container.

[0005] Chinese Patent CN202010629738.X discloses a variable stiffness picking manipulator based on the combination of rigidity and flexibility. The manipulator structure adopts a delat parallel mechanical structure and a telescopic cylinder as its rigid driving module, and uses flexible materials such as silicone to prepare a pneumatic cavity structure as its flexible variable stiffness gripper module for bending deformation. Magnetorheological elastomers are introduced into a specific silicone cavity structure, and the stiffness of the mechanical gripper structure is changed by the combined action of the bending deformation degree of the gripper structure and the change of the electromagnetic field intensity of the electromagnet. The cavity into which the magnetorheological elastomer is introduced and the mechanical gripper that undergoes bending deformation are an integral whole, and can be integrally prepared using 3D printing technology. In this study, the telescopic cylinder and the flexible variable stiffness gripper are connected by a wide-mouth conduit, and a pneumatic valve is used to control the air pressure to achieve the bending control of the flexible variable stiffness gripper.

[0006] Based on previous research and inventions, the following problems exist in the currently involved soft fruit and vegetable harvesting manipulators:

[0007] (1) Most adopt pneumatic drive methods, and the additional configuration of an air pump restricts the freedom of the robot's picking operation;

[0008] (2) Existing soft manipulators lack sufficient stiffness to complete the picking task.

[0009] (3) The dexterity of existing soft hands is insufficient. Most soft mechanical grippers rely on the fingertip part to complete the tasks of fruit fixation and grasping, resulting in a low grasping force.

[0010] Therefore, it is of great research significance to design a soft fruit and vegetable harvesting manipulator that is dexterous, has appropriate stiffness, and simple drive. Summary of the Invention

[0011] Aiming at the limitations of the above manipulator, the present invention provides a cable-driven bionic soft fruit and vegetable harvesting manipulator. The cable-driven bionic soft fruit and vegetable harvesting manipulator of the present invention is a soft picking manipulator constructed based on the human finger, having a certain stiffness, and realized through a cable drive method, and has the advantages of simple structure, softness, strong environmental adaptability, portability, simple drive, and portability.

[0012] To achieve the above solution, the technical solution adopted by the present invention is as follows:

[0013] A cable-driven bionic soft fruit and vegetable harvesting manipulator, comprising a gripper drive mechanism, a mechanical gripper, inner cables, and outer cables;

[0014] The described mechanical gripper includes several bionic fingers fixedly installed at the bottom of the lower flange. The bionic fingers can only bend in the radial inner and outer directions of the lower flange. The bionic fingers are composed of a series-connected upper phalanx ball-headed cylindrical connector, a middle phalanx ball-headed cylindrical connector, and a lower phalanx ball-headed cylindrical connector. The upper phalanx ball-headed cylindrical connector, the middle phalanx ball-headed cylindrical connector, and the lower phalanx ball-headed cylindrical connector include a cylindrical main body and a ball head located at the lower end face of the cylindrical main body with a diameter smaller than the outer diameter of the cylinder. A ball head hole is provided on the ball head, and an inner cylindrical hole and an outer cylindrical hole penetrating the upper and lower end faces are provided on the cylindrical main body. The plane formed by the center lines of the inner cylindrical hole and the outer cylindrical hole is coplanar with the bending plane of the bionic finger.

[0015] One end of the inner cable and the outer cable is fixed at the ball head hole on the ball head at the lower end face of the lower phalanx ball-headed cylindrical connector in the bionic finger. The other end of the inner cable passes through the inner cylindrical holes of the lower phalanx ball-headed cylindrical connector, the middle phalanx ball-headed cylindrical connector, and the upper phalanx ball-headed cylindrical connector in sequence and is fixed on the driving mechanism. The other end of the outer cable passes through the outer cylindrical holes of the lower phalanx ball-headed cylindrical connector, the middle phalanx ball-headed cylindrical connector, and the upper phalanx ball-headed cylindrical connector in sequence and is fixed on the driving mechanism. The driving mechanism can drive the inner cable and the outer cable to be tensioned and relaxed, so as to enable the bionic soft fruit and vegetable harvesting manipulator to complete the opening and grasping actions.

[0016] Further, the number of the bionic fingers is at least 3, and several bionic fingers are evenly distributed along the circumference of the lower flange.

[0017] Further, a silica gel sleeve is sleeved outside the upper phalanx ball-headed cylindrical connector, the middle phalanx ball-headed cylindrical connector, and the lower phalanx ball-headed cylindrical connector. The silica gel sleeve is fastened by a wound elastic fiber rope.

[0018] Further, a ball surface with hole grooves are also provided on the upper end faces of the middle phalanx ball-headed cylindrical connector and the lower phalanx ball-headed cylindrical connector.

[0019] The ball surface with hole grooves on the upper end face of the middle phalanx ball-headed cylindrical connector matches the ball head on the lower end face of the upper phalanx ball-headed cylindrical connector, and the hole on the ball surface with hole grooves matches the ball head hole on the ball head on the lower end face.

[0020] The ball surface with hole grooves on the upper end face of the lower phalanx ball-headed cylindrical connector matches the ball head on the lower end face of the middle phalanx ball-headed cylindrical connector, and the hole on the ball surface with hole grooves matches the ball head hole on the ball head on the lower end face.

[0021] Further, the hole on the ball surface with hole grooves is connected to the ball head hole on the ball head on the lower end face by a pin. The axis of the pin is perpendicular to the bending plane of the bionic finger.

[0022] Further, the central line of the ball head hole on the ball head at the lower end face of the lower phalangeal ball head cylindrical connector is coplanar with the bending plane of the bionic finger.

[0023] Further, the upper flange is also provided with threading through holes that match the inner cylindrical hole and the outer cylindrical hole of the upper phalangeal ball head cylindrical connector.

[0024] Further, the gripper driving mechanism includes a stepping motor, an upper flange, a U-shaped screw, a lead screw, and a transmission nut; the upper flange is installed above the lower flange through a support structure, the stepping motor is installed at the center of the upper flange, and the motor shaft of the stepping motor is connected to the lead screw and then penetrates through the upper flange; the transmission nut is installed on the lead screw and is located between the upper flange and the lower flange, and the transmission nut is provided with threading interfaces for fixing the inner cable and the outer cable along the circumferential direction; the U-shaped screw is installed at the bottom of the upper flange, and the number of U-shaped screws is the same as the number of bionic fingers.

[0025] Further, the inner cable passing through the inner cylindrical hole of the upper phalangeal ball head cylindrical connector is fixed at the threading interface of the transmission nut after passing through the threading through hole of the upper flange; the outer cable passing through the outer cylindrical hole of the upper phalangeal ball head cylindrical connector is fixed at the threading interface of the transmission nut after passing through the threading through hole of the upper flange and then winding around the U-shaped screw;

[0026] In the free state, the inner cable and the outer cable are not stressed, and the bionic finger hangs naturally; during the downward movement of the transmission nut, the inner cable is slack and the outer cable is tensioned, and the bionic finger bends radially outward along the lower flange, and the bionic soft fruit and vegetable harvesting manipulator opens; during the upward movement of the transmission nut, the inner cable is tensioned and the outer cable is slack, and the bionic finger bends radially inward along the lower flange, and the bionic soft fruit and vegetable harvesting machine grips.

[0027] Further, the installation positions of the U-shaped screws and the threading interface positions on the transmission nut correspond to the installation positions of several bionic fingers.

[0028] The beneficial effects of the present invention are as follows:

[0029] The present invention realizes the grasping function of the robotic claw hand by means of cable drive, avoiding the use of a large-sized air pump, so that the picking manipulator can have a large free operation space, with simple drive, strong compliance, and strong portability. In addition, the bionic soft fruit and vegetable harvesting manipulator proposed by the present invention is small in size and easy to manufacture, providing a new solution and new technology for the fruit and vegetable harvesting manipulator. Description of the Drawings

[0030] Figure 1 It is a schematic structural diagram of the cable-driven bionic soft fruit and vegetable harvesting manipulator when grasping.

[0031] Figure 2 It is a schematic structural diagram of a driving mechanism.

[0032] Figure 3 It is a schematic structural diagram of a mechanical gripper.

[0033] Figure 4 It is a schematic structural diagram of a bionic finger of a mechanical gripper.

[0034] Figure 5 It is a schematic diagram of the free state of a cable-driven bionic soft fruit and vegetable harvesting manipulator.

[0035] Figure 6 It is a schematic diagram of the open state of a cable-driven bionic soft fruit and vegetable harvesting manipulator.

[0036] Figure 7 It is a schematic structural diagram of an upper phalanx ball-headed cylindrical connector.

[0037] Figure 8 It is a schematic structural diagram of a middle phalanx ball-headed cylindrical connector.

[0038] Figure 9 It is a schematic structural diagram of a lower phalanx ball-headed cylindrical connector.

[0039] In the figure: 1 - stepping motor, 2 - upper flange, 3 - U-shaped screw, 4 - hexagon nut, 5 - outer cable, 6 - hexagonal copper column, 7 - lower flange fixing screw, 8 - lower flange, 9 - upper phalanx ball-headed cylindrical connector, 10 - hollow cylindrical silicone sleeve, 11 - elastic fiber rope, 12 - pin, 13 - middle phalanx ball-headed cylindrical connector, 14 - lower phalanx ball-headed cylindrical connector, 15 - ball-headed hollow cylindrical silicone sleeve, 16 - inner cable, 17 - transfer nut, 18 - lead screw, 19 - hexagon socket screw, 171 - hole around the transmission nut, 91 - ball head hole of the upper phalanx ball-headed cylindrical connector, 92 - inner cylindrical hole of the upper phalanx ball-headed cylindrical connector, 93 - outer cylindrical hole of the upper phalanx ball-headed cylindrical connector, 94 - flat hole of the upper phalanx ball-headed cylindrical connector, 131 - ball head hole of the middle phalanx ball-headed cylindrical connector, 132 - inner cylindrical hole of the middle phalanx ball-headed cylindrical connector, 133 - outer cylindrical hole of the middle phalanx ball-headed cylindrical connector, 134 - ball head with hole groove of the middle phalanx ball-headed cylindrical connector, 141 - ball head hole of the lower phalanx ball-headed cylindrical connector, 142 - inner cylindrical hole of the lower phalanx ball-headed cylindrical connector, 143 - outer cylindrical hole of the lower phalanx ball-headed cylindrical connector, 144 - ball head with hole groove of the lower phalanx ball-headed cylindrical connector. Detailed implementation mode

[0040] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation modes.

[0041] As Figure 1As shown in the figure, a cable-driven bionic soft fruit and vegetable harvesting manipulator mainly consists of a gripper driving mechanism, a mechanical gripper, an inner cable 16, and an outer cable 5.

[0042] In this embodiment, the gripper driving mechanism is composed of a stepper motor 1, an upper flange 2, a U-shaped screw 3, a hexagon nut 4, an internal hexagon screw 19, a lead screw 18, and a transmission nut 17;

[0043] The mechanical gripper is composed of a lower flange 8, bionic fingers, and lower flange fixing screws 7; Each bionic finger is composed of an upper phalanx ball-headed cylindrical connector 9, a middle phalanx ball-headed cylindrical connector 13, a lower phalanx ball-headed cylindrical connector 14, a pin 12, a hollow cylindrical silicone sleeve 10, a ball-headed hollow cylindrical silicone sleeve 15, and an elastic fiber rope 11; The gripper driving mechanism and the mechanical gripper are connected by three hexagonal copper posts 6;

[0044] The inner cable 16 and the outer cable 5 are respectively fixed in the ball head holes 141 of the lower phalanx ball-headed cylindrical connector 14. The inner cable 16 passes through the inner cylindrical hole 142 of the lower phalanx ball-headed cylindrical connector, the inner cylindrical hole 132 of the middle phalanx ball-headed cylindrical connector, the inner cylindrical hole 92 of the upper phalanx ball-headed cylindrical connector, and is fixedly connected to the lower end of the lower flange 8 and the transmission nut 17; The outer cable 5 passes through the outer cylindrical hole 143 of the lower phalanx ball-headed cylindrical connector, the outer cylindrical hole 133 of the middle phalanx ball-headed cylindrical connector, the outer cylindrical hole 93 of the upper phalanx ball-headed cylindrical connector, the lower flange 8 and bypasses the U-shaped screw 3 and is fixedly connected to the upper end of the transmission nut 17. By controlling the forward and reverse rotation of the lead screw 18 by the stepper motor 1 to control the up and down movement of the transmission nut 17, and then respectively controlling the stretching of the inner cable 16 and the outer cable 5, the closing and opening of the mechanical gripper are controlled to complete the fruit and vegetable picking task.

[0045] As Figure 2 shown, the gripper driving mechanism is composed of a stepper motor 1, an upper flange 2, a U-shaped screw 3, a hexagon nut 4, an internal hexagon screw 19, a lead screw 18, and a transmission nut 17; The stepper motor 1 is fixed on the upper flange 2 by four internal hexagon screws 19; The lead screw 18 is connected to the stepper motor 1 by welding technology so that its rotation is synchronized with the stepper motor 1. The transmission nut 17 is matched with the lead screw 18 by threads. By controlling the forward and reverse rotation of the stepper motor 1, the up and down transmission of the transmission nut 17 is controlled; The transmission nut 17 is provided with peripheral holes 171 for connecting the inner cable 16 and the outer cable 5 to realize the control of the stretching of the inner cable 16 and the outer cable 5; The U-shaped screw 3 is fixed on the upper flange 2 by a hexagon nut 4, and the outer cable 5 bypasses the U-shaped screw 3 and is connected to the peripheral hole 171 on the transmission nut 17.

[0046] As Figure 3As shown in the figure, the robotic gripper consists of a lower flange 8, bionic fingers, and lower flange fixing screws 7; each bionic finger is composed of an upper phalanx ball-headed cylindrical connector 9, a middle phalanx ball-headed cylindrical connector 13, a lower phalanx ball-headed cylindrical connector 14, a pin 12, a hollow cylindrical silicone sleeve 10, a ball-headed hollow cylindrical silicone sleeve 15, and an elastic fiber rope 11.

[0047] As Figure 7 shown, the main body of the upper phalanx ball-headed cylindrical connector 9 is of a cylindrical structure, and a ball head with a diameter smaller than the outer diameter of the cylinder is provided at the center of the lower end face. The upper phalanx ball-headed cylindrical connector 9 is provided with an upper phalanx ball-headed cylindrical connector ball head hole 91, an upper phalanx ball-headed cylindrical connector inner cylindrical hole 92, an upper phalanx ball-headed cylindrical connector outer cylindrical hole 93, and an upper phalanx ball-headed cylindrical connector flat hole 94; the upper phalanx ball-headed cylindrical connector flat hole 94 is located on the upper end face of the upper phalanx ball-headed cylindrical connector 9, and the upper phalanx ball-headed cylindrical connector flat hole 94 is fixed to the lower flange 8 by the lower flange fixing screw 7; the upper phalanx ball-headed cylindrical connector ball head hole 91 is located on the ball head at the lower end face of the upper phalanx ball-headed cylindrical connector 9, and the center line where the ball head hole 91 is located is perpendicular to the bending plane of the bionic finger. At the ball head hole 91, a hole on the ball head with a hole groove 134 of the middle phalanx ball-headed cylindrical connector is connected by a pin 12, restricting the middle phalanx ball-headed cylindrical connector 13 to bend only in the radial inner and outer directions of the lower flange 8; the upper phalanx ball-headed cylindrical connector inner cylindrical hole 92 and the upper phalanx ball-headed cylindrical connector outer cylindrical hole 93 penetrate the upper and lower end faces of the upper phalanx ball-headed cylindrical connector 9, and the plane formed by the center lines of the upper phalanx ball-headed cylindrical connector inner cylindrical hole 92 and the upper phalanx ball-headed cylindrical connector outer cylindrical hole 93 is coplanar with the bending plane of the bionic finger.

[0048] In this embodiment, through holes matching the upper phalanx ball-headed cylindrical connector inner cylindrical hole 92, the upper phalanx ball-headed cylindrical connector outer cylindrical hole 93, and the upper phalanx ball-headed cylindrical connector flat hole 94 are also provided on the lower flange 8.

[0049] As Figure 8As shown, the main body of the middle phalanx ball-ended cylindrical connector 13 is of a cylindrical structure, and a ball head with a diameter smaller than the outer diameter of the cylinder is provided at the center of the lower end face. The middle phalanx ball-ended cylindrical connector 13 is provided with a middle phalanx ball-ended cylindrical connector ball head hole 131, a middle phalanx ball-ended cylindrical connector inner cylindrical hole 132, a middle phalanx ball-ended cylindrical connector outer cylindrical hole 133, and a middle phalanx ball-ended cylindrical connector ball head with hole groove 134; the middle phalanx ball-ended cylindrical connector ball head with hole groove 134 is located on the upper end face of the middle phalanx ball-ended cylindrical connector 13, and the hole groove 134 with holes is matched with the ball head of the upper phalanx ball-ended cylindrical connector 9. The center line where the holes on the hole groove 134 are located is perpendicular to the bending plane of the bionic finger, and the holes on the hole groove 134 are matched with the ball head holes on the upper phalanx ball-ended cylindrical connector 9; the middle phalanx ball-ended cylindrical connector ball head hole 131 is located on the ball head at the lower end face of the middle phalanx ball-ended cylindrical connector 13, and the center line where the ball head hole 131 is located is perpendicular to the bending plane of the bionic finger. At the ball head hole 131, the hole on the ball head with hole groove 144 of the lower phalanx ball-ended cylindrical connector is connected through a pin 12, which can limit the lower phalanx ball-ended cylindrical connector 14 to bend only in the radial inner and outer directions along the lower flange 8; the middle phalanx ball-ended cylindrical connector inner cylindrical hole 132 and the middle phalanx ball-ended cylindrical connector outer cylindrical hole 133 penetrate through the upper and lower end faces of the middle phalanx ball-ended cylindrical connector 13, and the plane formed by the center lines of the middle phalanx ball-ended cylindrical connector inner cylindrical hole 132 and the middle phalanx ball-ended cylindrical connector outer cylindrical hole 133 is coplanar with the bending plane of the bionic finger.

[0050] As Figure 9As shown, the main body of the distal phalanx ball cylindrical connector 14 is a cylindrical structure, and a ball head with a diameter smaller than the outer diameter of the cylinder is provided at the center of the lower end face. The distal phalanx ball cylindrical connector 14 is provided with a distal phalanx ball cylindrical connector ball head hole 141, a distal phalanx ball cylindrical connector inner cylindrical hole 142, a distal phalanx ball cylindrical connector outer cylindrical hole 143, and a distal phalanx ball cylindrical connector ball head with hole groove 144. The distal phalanx ball cylindrical connector ball head with hole groove 144 is located on the upper end face of the distal phalanx ball cylindrical connector 14. The hole groove 144 with holes is matched with the ball head of the middle phalanx ball cylindrical connector 13. The center line of the hole on the hole groove 144 is perpendicular to the bending plane of the bionic finger. The hole on the hole groove 144 is matched with the ball head hole on the middle phalanx ball cylindrical connector 13. The distal phalanx ball cylindrical connector ball head hole 141 is located on the ball head at the lower end face of the distal phalanx ball cylindrical connector 14. The center line where the ball head hole 141 is located is coplanar with the bending plane of the bionic finger. The ball head hole 141 is used to fix one end of the inner cable 16 and the outer cable 5. The distal phalanx ball cylindrical connector inner cylindrical hole 142 and the distal phalanx ball cylindrical connector outer cylindrical hole 143 penetrate through the upper and lower end faces of the distal phalanx ball cylindrical connector 14. The plane formed by the center lines of the distal phalanx ball cylindrical connector inner cylindrical hole 142 and the distal phalanx ball cylindrical connector outer cylindrical hole 143 is coplanar with the bending plane of the bionic finger.

[0051] Through Figures 7 to 9 As can be seen from the structures of the upper, middle, and distal phalanx ball cylindrical connectors shown, the upper phalanx ball cylindrical connector 9 is fixed to the lower flange 8 through the plane hole 94 on the upper end face. The ball head with hole groove 134 on the upper end face of the middle phalanx ball cylindrical connector 13 is connected to the ball head at the lower end face of the upper phalanx ball cylindrical connector 9 through the pin 12, which can limit the middle phalanx ball cylindrical connector 13 to bend only in the radial inner and outer directions along the lower flange 8. The ball head with hole groove 144 on the upper end face of the distal phalanx ball cylindrical connector 14 is connected to the ball head at the lower end face of the middle phalanx ball cylindrical connector 13 through the pin 12, which can limit the distal phalanx ball cylindrical connector 14 to bend only in the radial inner and outer directions along the lower flange 8. A cylindrical silicone sleeve is also sleeved on the periphery of the upper, middle, and distal phalanx ball cylindrical connectors. Among them, the ball head hollow cylindrical silicone sleeve 15 is sleeved outside the distal phalanx ball cylindrical connector 14, and the two hollow cylindrical silicone sleeves 10 are respectively sleeved outside the middle phalanx ball cylindrical connector 13 and the upper phalanx ball cylindrical connector 9, which increases the softness and compliance of the robotic gripper. In this embodiment, the ball head hollow cylindrical silicone sleeve 15 and the hollow cylindrical silicone sleeve 10 are both wound around the outside of the bionic finger by the elastic fiber rope 11, which improves the grasping ability of the robotic gripper and can prevent the silicone sleeve from falling off.

[0052] In a specific implementation of the present invention, three bionic fingers are evenly fixed along the circumference below the lower flange 8 to form a three-jaw manipulator structure, and the structure of each bionic finger is the same.

[0053] As Figure 4 shown, the upper flange 2 in the gripper drive mechanism and the lower flange 8 in the mechanical gripper are connected by three hexagonal copper columns 6; one end of the inner cable 16 and the outer cable 5 are respectively fixed in the ball head holes 141 of the ball head on the lower end face of the lower phalanx ball head cylindrical connector 14, and the other end of the inner cable 16 sequentially passes through the inner cylindrical hole 142 of the lower phalanx ball head cylindrical connector, the inner cylindrical hole 132 of the middle phalanx ball head cylindrical connector, the inner cylindrical hole 92 of the upper phalanx ball head cylindrical connector, and the through hole of the lower flange 8 and is fixed at the peripheral hole 171 of the transfer nut 17; the other end of the outer cable 5 sequentially passes through the outer cylindrical hole 143 of the lower phalanx ball head cylindrical connector, the outer cylindrical hole 133 of the middle phalanx ball head cylindrical connector, the outer cylindrical hole 93 of the upper phalanx ball head cylindrical connector, the through hole of the lower flange 8 and bypasses the U-shaped screw 3 at the bottom of the upper flange and is fixed at the peripheral hole 171 of the transfer nut 17.

[0054] As Figure 5 shown, the inner cable 16 and the outer cable 5 are in a relaxed state when in a free state, and the three bionic fingers hang down naturally. As Figure 1 shown, when the stepping motor 1 drives the lead screw 18 to rotate forward, the transmission nut 17 rises, causing the inner cable 16 to stretch and the outer cable to be relaxed, driving the mechanical gripper to bend inward to form a grasping state; as Figure 6 shown, when the stepping motor 1 drives the lead screw 18 to rotate reversely, the transmission nut 17 descends, causing the outer cable 5 to stretch and the inner cable to be relaxed, driving the mechanical gripper to bend outward to form an open state.

[0055] For those of ordinary skill in the art, according to the teachings of the present invention, without departing from the principles and spirit of the present invention, the changes, modifications, substitutions, and variations made to the embodiments still fall within the protection scope of the present invention.

Claims

1. A cable-driven bionic soft fruit and vegetable harvesting manipulator, characterized in that, it includes a gripper driving mechanism, a mechanical gripper, an inner cable (16) and an outer cable (5); The mechanical gripper includes a number of bionic fingers fixedly installed at the bottom of the lower flange (8). The number of the bionic fingers is at least 3. The several bionic fingers are evenly distributed along the circumferential direction of the lower flange (8) and can only bend in the radial inner and outer directions of the lower flange (8). The bionic finger is composed of a series-connected upper phalanx ball-headed cylindrical connector (9), a middle phalanx ball-headed cylindrical connector (13), and a lower phalanx ball-headed cylindrical connector (14). The upper phalanx ball-headed cylindrical connector (9), the middle phalanx ball-headed cylindrical connector (13), and the lower phalanx ball-headed cylindrical connector (14) include a cylindrical body and a ball head located at the lower end face of the cylindrical body and having a diameter smaller than the outer diameter of the cylinder. A ball head hole is provided on the ball head. Inner cylindrical holes and outer cylindrical holes penetrating the upper and lower end faces are provided on the cylindrical body. The plane formed by the center lines of the inner cylindrical hole and the outer cylindrical hole is coplanar with the bending plane of the bionic finger. The center line of the ball head hole on the ball head at the lower end face of the lower phalanx ball-headed cylindrical connector (14) is coplanar with the bending plane of the bionic finger; Silicone sleeves are sleeved outside the upper phalanx ball-headed cylindrical connector (9), the middle phalanx ball-headed cylindrical connector (13), and the lower phalanx ball-headed cylindrical connector (14). The silicone sleeves are fastened by wound elastic fiber ropes. The lower flange (8) is also provided with threading through holes matching the inner cylindrical holes and outer cylindrical holes of the upper phalanx ball-headed cylindrical connector (9); One ends of the inner cable (16) and the outer cable (5) are both fixed at the ball head holes on the ball head at the lower end face of the lower phalanx ball-headed cylindrical connector (14) in the bionic finger. The other end of the inner cable (16) sequentially passes through the inner cylindrical holes of the lower phalanx ball-headed cylindrical connector, the middle phalanx ball-headed cylindrical connector (13), the upper phalanx ball-headed cylindrical connector (9), and the threading through holes of the lower flange (8) and is fixed on the gripper driving mechanism. The other end of the outer cable (5) sequentially passes through the outer cylindrical holes of the lower phalanx ball-headed cylindrical connector, the middle phalanx ball-headed cylindrical connector (13), the upper phalanx ball-headed cylindrical connector (9), and the threading through holes of the lower flange (8) and is fixed on the gripper driving mechanism. The gripper driving mechanism can drive the inner cable (16) and the outer cable (5) to be tightened and relaxed, so as to enable the bionic soft fruit and vegetable harvesting manipulator to complete the opening and grasping actions; Specifically, the gripper driving mechanism includes a stepper motor (1), an upper flange (2), a U-shaped screw (3), a lead screw (18), and a transmission nut (17); the upper flange (2) is installed above the lower flange (8) through a support structure, the stepper motor (1) is installed at the center of the upper flange (2), and the motor shaft of the stepper motor (1) is connected to the lead screw (18) and penetrates through the upper flange (2); the transmission nut (17) is installed on the lead screw and is located between the upper flange and the lower flange, and the transmission nut (17) is provided with wire threading interfaces for fixing the inner cable (16) and the outer cable (5) along the circumferential direction; the U-shaped screw (3) is installed at the bottom of the upper flange (2), and the number of U-shaped screws (3) is the same as the number of bionic fingers; The inner cable (16) passing through the inner cylindrical hole of the upper phalanx ball-headed cylindrical connector (9) is fixed at the wire threading interface of the transmission nut (17) after passing through the wire threading through-hole of the lower flange (8); the outer cable (5) passing through the outer cylindrical hole of the upper phalanx ball-headed cylindrical connector (9) passes through the wire threading through-hole of the lower flange (8) and then is fixed at the wire threading interface of the transmission nut (17) after passing around the U-shaped screw (3); the installation positions of the U-shaped screws (3) and the wire threading interface positions on the transmission nut (17) correspond to the installation positions of several bionic fingers; In the free state, the inner cable and the outer cable are not stressed, and the bionic fingers hang down naturally; during the downward movement of the transmission nut (17), the inner cable is slack and the outer cable is tensioned, and the bionic fingers bend radially outward along the lower flange (8), and the bionic soft fruit and vegetable harvesting manipulator opens; during the upward movement of the transmission nut (17), the inner cable is tensioned and the outer cable is slack, and the bionic fingers bend radially inward along the lower flange (8), and the bionic soft fruit and vegetable harvesting manipulator grasps.

2. A cable-driven bionic soft fruit and vegetable harvesting manipulator according to claim 1, characterized in that, the upper end faces of the middle phalanx ball-headed cylindrical connector (13) and the lower phalanx ball-headed cylindrical connector (14) are also provided with spherical surface grooved holes; the spherical surface grooved hole on the upper end face of the middle phalanx ball-headed cylindrical connector (13) matches the ball head on the lower end face of the upper phalanx ball-headed cylindrical connector (9), and the hole on the spherical surface grooved hole matches the ball head hole on the ball head on the lower end face; the spherical surface grooved hole on the upper end face of the lower phalanx ball-headed cylindrical connector (14) matches the ball head on the lower end face of the middle phalanx ball-headed cylindrical connector (13), and the hole on the spherical surface grooved hole matches the ball head hole on the ball head on the lower end face.

3. A cable-driven bionic soft fruit and vegetable harvesting manipulator according to claim 2, characterized in that, the hole on the spherical surface grooved hole is connected to the ball head hole on the ball head on the lower end face through a pin (12), and the axis of the pin is perpendicular to the bending plane of the bionic finger.

Images