Rope-driven isobaric pneumatic self-adaptive fruit gripping device

Abstract

A rope-driven isobaric pneumatic self-adaptive fruit gripping device comprises a soft gripper and an inflating and deflating unit used for inflating and deflating the soft gripper. The soft gripper comprises a fixing part and at least two clamping jaws, the clamping jaws are elastic bodies, and each clamping jaw comprises a main body part and a bag; the main body part is provided with a grabbing side and a non-grabbing side which are opposite to each other in the thickness direction of the main body part, and the grabbing side and the non-grabbing side are connected through a first limiting connecting piece so as to limit the distance between the grabbing side and the non-grabbing side not to exceed a first threshold value during inflation; the bags are distributed on the non-grabbing side of the main body part at intervals in the length direction of the main body part. Each bag is provided with two opposite faces in the length direction of the main body part, and the two opposite faces are connected through a second limiting connecting piece. According to the fruit grabbing device, multi-point self-adaptive wrapping and uniform and controllable pressure can be achieved, power can be arranged at the rear portion, the structure is compact, and the efficient, lossless and stable fruit grabbing requirement is met.

Description

Technical Field

[0001] This invention relates to the field of harvesting robot technology, specifically a rope-driven isobaric pneumatic adaptive fruit grasping device. Background Technology

[0002] In automated operations such as fruit and vegetable harvesting, grading, and packaging, robotic end effectors must be capable of reliably and non-destructively grasping the fruit. Because fruit shape and size vary significantly from one another, and their skin is fragile and easily damaged, the grasping device must possess excellent adaptability and precise force control performance.

[0003] Currently, common fruit-grabbing devices mainly include mechanical gripping, vacuum adsorption, and combined adsorption and gripping types. Based on their structure, they can be further divided into rigid grippers, soft grippers, and rigid-flexible coupling end effectors. However, existing devices still have shortcomings in the following aspects: Limited adaptive wrapping ability: Most rigid or underactuated grippers cannot fully conform to the uneven surface of the fruit, and have poor adaptability to irregularly shaped fruits or changes in size. Uneven pressure distribution: Local stress concentration is easily generated during the grasping process, which can lead to mechanical damage to the fruit, especially during high-acceleration dynamic operations; The end effector is bulky: the drive components (such as motors and pneumatic muscles) are mostly integrated inside the gripper, resulting in a large end effector inertia, which limits the robot's movement speed and operational flexibility.

[0004] In summary, existing fruit-grabbing devices struggle to simultaneously meet the combined requirements of adaptive wrapping, uniform pressure distribution, and lightweight end effector. Therefore, it is necessary to develop a novel end effector. Summary of the Invention

[0005] The purpose of this invention is to propose a rope-driven isobaric pneumatic adaptive fruit grasping device. This device can achieve multi-point adaptive wrapping and uniform and controllable pressure, and can also achieve rear-mounted power and compact structure to meet the requirements of efficient, non-destructive and stable fruit grasping.

[0006] The technical solution adopted in this invention is: a rope-driven isobaric pneumatic adaptive fruit grasping device, including a soft gripper and an inflation / deflation unit for inflating and deflating the soft gripper; The soft gripper includes a fixed part and at least two grippers, the grippers being elastic bodies, each gripper including a main body and a pouch; The main body has opposing gripping and non-gripping sides in its thickness direction. The gripping and non-gripping sides are connected by a first limiting connector to limit the distance between the gripping and non-gripping sides during inflation to not exceed a first threshold. The pouches are spaced along the length of the main body on its non-gripping side; each pouch has two opposing surfaces along the length of the main body, and the two opposing surfaces are connected by a second limiting connector to limit the distance between the two opposing surfaces to not exceed a second threshold when inflated; when inflated, each pouch can elastically expand along the length of the main body, pushing the main body to bend toward its gripping side; when deflated, each pouch can elastically recover along the length of the main body, causing the main body to bend back toward its non-gripping side. The gripping side of the main body has piston chambers spaced along its length, and a clamping piston is slidably disposed in each piston chamber. When inflated, the clamping piston moves toward the gripping side under the action of air pressure in the gripper. When deflated, the clamping piston moves toward the non-gripping side to reset under the action of negative pressure when the gripper elastically recovers.

[0007] As a preferred embodiment, there are three grippers, which are distributed at equal angles along the center of the fixing part; the inner cavity of the fixing part communicates with the inner cavities of all the grippers.

[0008] As a preferred embodiment, both the first limiting connector and the second limiting connector are made of fiber filaments, and the fiber filaments are arranged in clusters.

[0009] As a preferred embodiment, the first limiting connector is located at the gap between adjacent pouches.

[0010] As a preferred embodiment, the clamping piston includes a rod portion that is in a sealing and sliding fit with the corresponding piston cavity. The inner end of the rod portion is provided with a limiting portion that restricts the rod portion from disengaging from the piston cavity, and the outer end of the rod portion is provided with a clamping portion for abutting the fruit.

[0011] As a preferred option, the clamping part is arc-shaped.

[0012] As a preferred embodiment, a guide is fixed to the inner side of the gripping side of the main body, and the guide slides in conjunction with the rod.

[0013] As a preferred embodiment, the inflation / deflation unit includes an air cylinder fixing component, on which an air cylinder is fixed, and an inflation piston is slidably disposed inside the air cylinder. The rodless chamber of the air cylinder is connected to the inner cavity of the soft gripper through an inflation tube.

[0014] As a preferred option, the inflation tube is a rigid tube.

[0015] As a preferred embodiment, it also includes a transmission unit for driving the inflatable piston; The transmission unit includes a guide hose that passes through the air cylinder and a fixed pulley fixed to the rod chamber of the air cylinder. A rope is threaded through the guide hose. The inner end of the rope passes around the fixed pulley and is fixedly connected to the inflation piston. The outer end of the rope extends to the outside of the air cylinder.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. Adaptive Wrapping and Isobaric Force Integration Design: The maximum gripping posture of the soft gripper body is controlled by limiting fiber optics, and local fine-tuning is achieved by isobaric pneumatic pistons. This ensures a tight fit to fruits of different shapes and sizes, eliminating the need for pre-set clamps or programming and enhancing adaptability. Simultaneously, all rodless chambers of the pneumatic pistons are interconnected, ensuring equal air pressure and consistent positive pressure on the fruit at each contact point. This prevents localized stress concentration and effectively protects the fruit's skin.

[0017] 2. Precise and controllable gripping force: The gripping force is only related to the inflation pressure. The gripping force can be precisely controlled by adjusting the air pressure through the rope drive, adapting to the pressure resistance of different fruits and taking into account both gripping stability and non-damage requirements.

[0018] 3. Lightweight, Flexible, and Sealed Structure with Rope-Driven Pneumatic Coordination: Power components such as the drive motor are positioned rearward on the robot base and remotely transmitted via ropes. The actuator retains only a soft airbag and a pneumatic piston, achieving a lightweight end effector with low inertia, significantly improving the robot's movement speed and operational flexibility. Simultaneously, the rope-driven structure offers flexible and noiseless arrangement; the pneumatic components achieve uniform force application and adaptive fit. The combination of these two features leverages the dual advantages of rear-mounted power and uniform force application. The actuator has no exposed motors or electrical interfaces, allowing for a fully sealed structure suitable for humid, dusty agricultural and food processing environments requiring frequent washing.

[0019] 4. Synergistic advantages of rope drive and pneumatic combination: The rope drive structure realizes rear-mounted power, which can achieve greater tensile force, lightweight end effect, flexible transmission path arrangement, and no motor noise interference; the pneumatic drive gives the gripper the ability to apply force evenly and adapt to fit. The combination of the two overcomes the shortcomings of traditional pneumatic system back-end equipment being large in size and noisy, while retaining its advantages such as controllable pressure and strong adaptability, forming an ideal gripping solution that combines flexible transmission and precise force control. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is an overall schematic diagram of the present invention; Figure 2 This is a cross-sectional view of the gripper in this invention; Figure 3 This is a schematic diagram of the piston clamping mechanism in this invention; Figure 4This is a cross-sectional schematic diagram of the sac in this invention; Figure 5 This is a schematic diagram of the inflation / deflation unit in this invention; Figure 6 This is a schematic diagram of the gripper in the initial stage of the present invention; Figure 7 This is a schematic diagram of the gripper in the coarse gripping stage of the present invention; Figure 8 This is a side view of the gripper in the precise gripping stage of the present invention; Figure 9 This is a top view of the gripper in the precise gripping stage of the present invention; Figure 10 This is a schematic diagram of the driving unit in this invention.

[0022] Reference numerals: 1. Fixing part; 2. Gripper; 201. Main body; 202. Bag; 203. First limiting connector; 204. Second limiting connector; 205. Piston chamber; 206. Clamping piston; 2061. Rod; 2062. Clamping part; 2063. Limiting part; 3. Inflation / deflation unit; 301. Air cylinder fixing part; 302. Air cylinder; 303. Inflation piston; 304. Inflation tube; 4. Guide hose; 5. Fixed pulley; 6. Rope; 7. Guide; 8. Drive motor; 9. Winding wheel. Detailed Implementation

[0023] The present invention will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0024] It should be noted that, unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "a," "an," or "the," etc., used in the specification and claims of this patent application do not express a limitation on quantity, but rather indicate the presence of at least one; the terms "first," "second," and "third," as used herein, should not be considered as a limitation on the order of components, but are merely for distinguishing different components; the terms "comprising," "including," etc., indicate that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, but do not exclude other elements or objects having the same function.

[0025] To more clearly describe this rope-driven isobaric pneumatic adaptive fruit-grabbing device, combined with the attached... Figure 1-10 This embodiment is described as follows: like Figure 1-5As shown, a rope-driven isobaric pneumatic adaptive fruit grasping device includes an execution unit, an inflation / deflation unit 3, a transmission unit, and a drive unit.

[0026] The soft gripper serves as an execution unit and includes a fixing part 1 and at least two grippers 2. The inner cavity of the fixing part 1 communicates with the inner cavities of all the grippers 2. The fixing part 1 has a pre-set air hole for inflation and deflation. For example, the figure shows three grippers 2, which are distributed at equal angles along the center of the fixing part 1 to maintain the uniformity of force on the fruit during the gripping process. The gripper 2 is an elastic body, and each gripper 2 includes a main body 201 and a pouch 202.

[0027] The main body 201 has a grasping side (the side that fits against the fruit being grasped) and a non-grasping side in its thickness direction. The grasping side and the non-grasping side are connected by a first limiting connector 203 to limit the distance between the grasping side and the non-grasping side during inflation to not exceed a first threshold. Under the first threshold, the distance between the grasping side and the non-grasping side at each position is basically the same, which prevents the main body 201 from deforming and ensures that the main body 201 can bend and grasp under the action of the pouch 202.

[0028] The pouches 202 are spaced along the length of the main body 201 on its non-grasping side; each pouch 202 has two opposing surfaces in the length of the main body 201, and the two opposing surfaces are connected by a second limiting connector 204 to limit the distance between the two opposing surfaces during inflation to not exceed a second threshold. Under the second threshold, the expansion amount of each pouch 202 is basically the same. When inflated, each pouch 202 can elastically expand in the length of the main body 201, pushing the main body 201 to bend toward its grasping side to achieve a grasping action; when deflated, each pouch 202 can elastically recover in the length of the main body 201, causing the main body 201 to bend back toward its non-grasping side to achieve a release action.

[0029] The grasping side of the main body 201 has piston chambers 205 spaced apart along its length, and a clamping piston 206 is slidably disposed in each piston chamber 205. When inflating, the air pressure in the gripper 2 drives the clamping piston 206 to move toward the grasping side, and the clamping piston 206 extends to clamp the fruit. When deflating, the negative pressure when the gripper 2 elastically recovers drives the clamping piston 206 to move back toward the non-grasping side, the clamping piston 206 retracts, and the fruit is released.

[0030] The first limiting connector 203 is located in the gap between adjacent pouches 202. Both the first limiting connector 203 and the second limiting connector 204 are fiber filaments. The length of the fiber filaments is greater than the distance between the gripping side and the non-gripping side or the distance between two opposing surfaces. The length of the fiber filaments hardly changes during the pulling process of the gripper 2. The fiber filaments are arranged in clusters to ensure their own strength while making the deformation at the corresponding positions of the main body 201 and the pouches 202 more uniform.

[0031] In the above embodiment, the clamping piston 206 includes a rod 2061 that is slidably sealed with the corresponding piston cavity 205. The inner end of the rod 2061 is provided with a limiting part 2063 that restricts the rod 2061 from disengaging from the piston cavity 205, and the outer end of the rod 2061 is provided with a clamping part 2062 for abutting the fruit. The clamping part 2062 is arc-shaped to conform to the curved surface of the fruit. The clamping part 2062 can be made of rubber, which is not easy to damage the skin of the fruit during the clamping process. A guide 7 is fixed on the inner side of the grasping side of the main body 201. The guide 7 is slidably engaged with the rod 2061 to ensure the stability of the clamping piston 206 during the extension and retraction process.

[0032] The inflation / deflation unit 3 is connected to the soft gripper and is used to inflate and deflate the soft gripper to control its grasping and releasing actions. The inflation / deflation unit 3 includes an air cylinder fixing member 301, on which an air cylinder 302 is fixed. An inflation piston 303 is slidably disposed within the air cylinder 302. The rodless chamber of the air cylinder 302 communicates with the inner cavity of the soft gripper through an inflation pipe 304, which is a rigid pipe directly connected to and communicating with the fixing part 1. When the inflation piston 303 is compressed, the gas in the rodless chamber is forced into the soft gripper, increasing the internal pressure. After the inflation piston 303 is released, the gas in the soft gripper is forced into the rodless chamber by the internal pressure and elastic recovery of the soft gripper, the inflation piston 303 resets, and the soft gripper returns to its initial state.

[0033] The transmission unit includes a transmission unit and a drive unit; the transmission unit includes a guide hose 4 that passes through the air cylinder 302 and a fixed pulley 5 fixed in the rod chamber of the air cylinder 302. A rope 6 passes through the guide hose 4, and the inner end of the rope 6 is fixedly connected to the inflation piston 303 after passing over the fixed pulley 5. The outer end of the rope 6 extends to the outside of the air cylinder 302. (See reference...) Figure 10 The drive unit includes at least one drive motor 8 and a winding reel 9. The outer end of the rope 6 is wound around the winding reel 9. The output shaft of the drive motor 8 is fixedly connected to the center of the winding reel 8. The drive motor 8 drives the winding reel 9 to rotate, which in turn drives the rope 6 of the transmission unit, causing the inflation piston 303 to slide inside the air cylinder 302. Through the rope-driven design of the transmission unit and the drive unit, the execution unit can be placed at the free end of the robotic arm (not shown in the figure), and the drive unit can be placed at the base end of the robotic arm, realizing remote traction of the execution unit by the drive unit.

[0034] The specific working process of this invention is divided into two stages: the coarse clamping stage and the precise clamping stage.

[0035] Initial state (e.g.) Figure 6 (As shown): The soft gripper is under normal pressure, the inflatable piston 303 is in the retracted state, and the first limiting connector 203 and the second limiting connector 204 are in the relaxed state. Coarse clamping stage (e.g.) Figure 7 As shown): The drive motor pulls the rope 6 through the winding wheel. The rope 6 is guided by the guide hose 4, which moves the soft gripper closer to the target fruit. At the same time, the inflation / deflation unit 3 inflates the fixed part 1 of the soft gripper through the inflation pipe 304. The gas enters the main body 201 and the pouch 202 of each gripper 2. The pouch 202 expands, causing the main body 201 of the gripper 2 to gradually bend and initially wrap the fruit. When the gripper 2 bends to the tension of the first limiting connector 203 and the second limiting connector 204, it reaches the preset maximum gripping posture. At this time, the gripping piston 206 has not yet extended. Precision clamping stage (e.g.) Figure 8 and Figure 9 As shown): After the first limiting connector 203 and the second limiting connector 204 are tensioned, air continues to be injected into the fixing part 1 of the soft gripper. The air pressure increases and acts on the bottom of the inner end of each gripping piston 206, pushing the gripping piston 206 to extend from the inside. The gripping part 2062 of the gripping piston 206 adaptively conforms to the uneven surface of the fruit. Since the chambers where all gripping pistons 206 are located are interconnected and the air pressure is equal, the positive thrust of each gripping piston 206 on the fruit is the same, achieving uniform force application and completing non-destructive gripping.

[0036] After the grasping task is completed, the drive motor reverses, releasing rope 6 and causing the execution unit to detach from the fruit. Simultaneously, inflation or deflation stops, the soft gripper returns to its initial shape under elastic action, and the clamping piston 206 retracts under internal negative pressure, returning the device to its initial state.

[0037] The parts not described in detail in the above embodiments are existing technologies.

[0038] It should be noted that although the present invention has been described through the above embodiments, the present invention may have many other embodiments. Without departing from the spirit and scope of the present invention, those skilled in the art can obviously make various corresponding changes and modifications to the present invention, but all such changes and modifications should fall within the scope of protection of the appended claims and their equivalents.

Claims

1. A rope-driven isobaric pneumatic adaptive fruit grasping device, characterized in that: Includes a soft gripper and an inflation / deflation unit for inflating and deflating the soft gripper (3); The soft gripper includes a fixed part (1) and at least two grippers (2), the grippers (2) being elastic bodies, each gripper (2) including a main body part (201) and a pouch (202). The main body (201) has opposing gripping and non-gripping sides in its thickness direction, and the gripping and non-gripping sides are connected by a first limiting connector (203) to limit the distance between the gripping and non-gripping sides during inflation to not exceed a first threshold. The pouches (202) are spaced along the length of the main body (201) on its non-grasping side; each pouch (202) has two opposing surfaces in the length of the main body (201), and the two opposing surfaces are connected by a second limiting connector (204) to limit the distance between the two opposing surfaces during inflation to not exceed a second threshold; when inflated, each pouch (202) can elastically expand in the length of the main body (201), pushing the main body (201) to bend toward its grasping side; when deflated, each pouch (202) can elastically recover in the length of the main body (201), causing the main body (201) to bend back toward its non-grasping side; The gripping side of the main body (201) is provided with piston chambers (205) spaced along its length, and a clamping piston (206) is slidably disposed in each piston chamber (205); when inflated, the clamping piston (206) is driven to move toward the gripping side under the action of air pressure in the gripper (2); when deflated, the clamping piston (206) is driven to move toward the non-gripping side to reset under the action of negative pressure when the gripper (2) elastically recovers.

2. The rope-driven isobaric pneumatic adaptive fruit grasping device according to claim 1, characterized in that: There are three grippers (2), which are distributed at equal angles along the center of the fixing part (1); The inner cavity of the fixing part (1) is connected to the inner cavities of all the grippers (2).

3. The rope-driven isobaric pneumatic adaptive fruit grasping device according to claim 1, characterized in that: Both the first limiting connector (203) and the second limiting connector (204) are fiber filaments, and the fiber filaments are arranged in clusters.

4. The rope-driven isobaric pneumatic adaptive fruit grasping device according to claim 1, characterized in that: The first limiting connector (203) is located in the gap between the adjacent pouches (202).

5. The rope-driven isobaric pneumatic adaptive fruit grasping device according to claim 1, characterized in that: The clamping piston (206) includes a rod (2061) that is in a sealing sliding fit with the corresponding piston chamber (205). The inner end of the rod (2061) is provided with a limiting part (2063) that restricts the rod (2061) from disengaging from the piston chamber (205), and the outer end of the rod (2061) is provided with a clamping part (2062) for abutting the fruit.

6. The rope-driven isobaric pneumatic adaptive fruit grasping device according to claim 5, characterized in that: The clamping part (2062) is arc-shaped.

7. The rope-driven isobaric pneumatic adaptive fruit grasping device according to claim 5, characterized in that: The inner side of the gripping side of the main body (201) is fixed with a guide (7), and the guide (7) slides with the rod (2061).

8. The rope-driven isobaric pneumatic adaptive fruit grasping device according to claim 1, characterized in that: The inflation / deflation unit (3) includes an air cylinder fixing component (301), an air cylinder (302) is fixed on the air cylinder fixing component (301), an inflation piston (303) is slidably arranged inside the air cylinder (302), and the rodless cavity of the air cylinder (302) is connected to the inner cavity of the soft gripper through an inflation tube (304).

9. A rope-driven isobaric pneumatic adaptive fruit grasping device according to claim 8, characterized in that: The inflation tube (304) is a rigid tube.

10. A rope-driven isobaric pneumatic adaptive fruit grasping device according to claim 8, characterized in that: It also includes a transmission unit for driving the pneumatic piston (303); The transmission unit includes a guide hose (4) that passes through the air cylinder (302) and a fixed pulley (5) fixed in the rod chamber of the air cylinder (302). A rope (6) is threaded through the guide hose (4). The inner end of the rope (6) passes around the fixed pulley (5) and is fixedly connected to the inflation piston (303). The outer end of the rope (6) extends to the outside of the air cylinder (302).

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