Tomato picking manipulator with self-adaptive telescopic fingers and picking method thereof

Abstract

The invention discloses a tomato picking manipulator with self-adaptive telescopic fingers and a picking method of the tomato picking manipulator. Arc-shaped bases of two telescopic clamping fingers which are symmetrically arranged are oppositely arranged and are driven by a driving mechanism to move oppositely or oppositely; the arc-shaped base is provided with a plurality of sliding grooves which are arranged at equal intervals in the circumferential direction, the sliding grooves are arranged in the radial direction, and each sliding groove is provided with a telescopic finger. One end of a near knuckle in the telescopic finger and the corresponding sliding groove form a sliding pair and are fixed to one end of an elastic rope, the other end of the elastic rope penetrates through a first through hole formed in the inner end of the corresponding sliding groove and is fixed to the arc-shaped base, and the other end of the near knuckle and a straight hole formed in the far knuckle form a sliding pair and are connected with the straight hole through a steel wire rope. And a reset spring is arranged in the straight hole. The tomato picking machine can realize tomato picking work, has an obstacle avoidance function, can realize complete enveloping of tomatoes, can adapt to irregular shapes of tomatoes, and is not easy to damage the skin of target tomatoes.

Description

Technical Field

[0001] The present invention belongs to the technical field of agricultural and forestry machinery, and particularly relates to a tomato picking manipulator with self-adaptive telescopic fingers and a picking method thereof. Background Art

[0002] When traditional manipulators pick cluster tomatoes, the clamping or enveloping actions are likely to collide with surrounding fruits or branches, resulting in picking failure. Moreover, due to the irregular shape of tomatoes, it is difficult for traditional finger structures such as parallel two-finger and three-finger structures to completely envelop the tomatoes, which easily leads to unstable clamping or excessive local pressure, causing damage to the fruit skin. Existing self-adaptive clamping mechanisms such as pneumatic soft hands can conform to the shape of the fruit, but have a slow response speed and are difficult to take into account the obstacle avoidance function. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and propose a tomato picking manipulator with self-adaptive telescopic fingers and a picking method thereof.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] A tomato picking manipulator with self-adaptive telescopic fingers of the present invention includes a housing, a driving mechanism, and two telescopic fingers driven by the driving mechanism to open and close.

[0006] The telescopic fingers include finger plates and telescopic fingers; the finger plates include arc-shaped bases, pulleys, and rope buckles. The arc-shaped bases form a sliding pair with the housing. The outer ends of the arc-shaped bases are provided with n chutes arranged equidistantly in the circumferential direction, n≥4, and each chute is arranged radially. A through hole one is provided at the inner end of each chute, and an outer cover plate is fixed at the outer end. n pulleys arranged equidistantly in the circumferential direction and respectively aligned with the through hole one are hinged inside the arc-shaped base, and n rope buckles arranged equidistantly in the circumferential direction and respectively aligned with the pulleys are fixed outside. The telescopic fingers include proximal phalanges, distal phalanges, and steel wire ropes. The proximal phalanges and the straight holes provided on the distal phalanges form a sliding pair, and a return spring is arranged coaxially in the straight hole. One end of the steel wire rope is fixed to the end of the straight hole far from the proximal phalanx, and the other end passes through the return spring and is fixed to the proximal phalanx. An integrally formed arc-shaped baffle is provided at one end of the inner side of the distal phalanx close to the proximal phalanx; one telescopic finger is provided on the arc-shaped base at each chute. The proximal phalanx of each telescopic finger is perpendicular to the arc-shaped base. One end of each proximal phalanx far from the distal phalanx forms a sliding pair with the corresponding chute and is fixed to one end of an elastic rope. The other end of each elastic rope passes through the corresponding through hole one, bypasses the corresponding pulley, and is fixed to the corresponding rope buckle.

[0007] Among them, each return spring is in a compressed state, each elastic rope is in a stretched state, and in the initial state, each steel wire rope is in a tension state.

[0008] Preferably, the driving mechanism includes a gear, a connecting rod, a finger support, and a guide rod group. The gear is placed inside the housing, forms a rotating pair with the housing, and is driven by a steering gear which is controlled by a controller. There are two finger supports arranged on both sides of the gear inside the housing. Both finger supports form a sliding pair with the housing, and racks are integrally formed on the inner sides of both finger supports. Both racks mesh with the gear, and two connecting rods are fixed on each of the two finger supports. The arc-shaped bases of the two telescopic finger clips are respectively fixed to the two connecting rods, and the symmetry center plane of the two telescopic finger clips is perpendicular to the rack.

[0009] More preferably, the housing of the steering gear is fixed inside the housing, and the output shaft is fixed to the gear.

[0010] More preferably, two symmetrically arranged guide rod groups are arranged on both sides of the gear inside the housing. The guide rod group consists of a plurality of guide rods I arranged at intervals. Each guide rod I is arranged in parallel, perpendicular to the gear, and fixed to the housing. Two through-hole groups are symmetrically arranged at both ends of each finger support. The through-hole group consists of a plurality of through-holes II arranged at intervals. Each pair of aligned through-holes II at both ends of each finger support is fixed to both ends of a sleeve, and each sleeve on each finger support is sleeved on a guide rod I of the same-side guide rod group, forming a sliding pair with the corresponding guide rod I. Each connecting rod is fixed to each sleeve on the corresponding finger support.

[0011] More preferably, a guide rod II parallel to the guide rod I is also fixed inside the housing between the two guide rod groups. Both connecting rods form a sliding pair with the guide rod II.

[0012] Preferably, a counterbore is provided at one end of the straight hole away from the proximal phalanx. A through-hole III is provided on the proximal phalanx. One end of the steel wire rope is fixed to the counterbore, the other end passes through the return spring, and then passes into the through-hole III and is fixed to the through-hole III.

[0013] Preferably, a V-shaped wire groove is provided on the pulley; each elastic rope bypasses the V-shaped wire groove of the corresponding pulley and is fixed to the corresponding rope buckle.

[0014] The picking method of a tomato picking manipulator with self-adaptive telescopic fingers according to the present invention is as follows:

[0015] Install the outer shell on the robotic arm. In the initial state, the two telescopic clamping fingers are in a separated state. The robotic arm drives the outer shell to move towards the position of the target tomato, so that the target tomato is located within the envelope space formed by each arc-shaped baffle on the two telescopic clamping fingers. At the same time, if the adjacent tomatoes or branches of the target tomato touch part of the end of the distal phalanx, some of the distal phalanges are blocked. The blocked distal phalanges move towards the direction close to the arc-shaped base, and the corresponding return springs are further compressed, and the corresponding steel wires are relaxed, while the unblocked distal phalanges remain unchanged. Then the driving mechanism drives the two arc-shaped bases to move towards each other, and then drives the two telescopic clamping fingers to move towards each other, so that the two telescopic clamping fingers close to envelope the target tomato. And when each distal phalanx contacts the irregular surface of the target tomato, each distal phalanx drives the proximal phalanx to move outwards along the corresponding chute, and the elastic ropes are further stretched. Then the robotic arm drives the outer shell to rotate around its own central axis to twist the target tomato off. The robotic arm then drives the outer shell to move above the collection basket. The blocked distal phalanges move towards the direction away from the arc-shaped base to their original positions under the restoring force of the corresponding return springs. The driving mechanism drives the two arc-shaped bases to move away from each other, so that the two telescopic clamping fingers expand to their original positions. At the same time, each distal phalanx is separated from the target tomato, and the target tomato falls into the collection basket. Each elastic rope pulls each proximal phalanx to move inwards to its original position, thus completing the picking work of the target tomato.

[0016] The present invention has the following beneficial effects:

[0017] 1. The present invention can achieve the picking of tomatoes, and has an obstacle avoidance function, can achieve the complete envelope of tomatoes, improve the picking success rate, can also adapt to the irregular shape of tomatoes, and has a relatively fast response speed, is not easy to damage the epidermis of the target tomato, and reduces the fruit damage rate. Specifically, in the present invention, the driving mechanism drives two telescopic fingers to move relative to or away from each other, so that the two telescopic fingers are closed or opened, and then the clamping or loosening of the target tomato can be realized. When clamping the target tomato, the manipulator drives the present invention to rotate, so that the target tomato is twisted off, thus the picking work of the target tomato can be realized. And each telescopic finger adopts a plurality of telescopic fingers evenly distributed in the circumferential direction. When the manipulator drives the present invention to move to the position of the target tomato, if the adjacent tomatoes or branches of the target tomato touch the distal phalanx ends of some telescopic fingers, some telescopic fingers are blocked. The distal phalanxes of the blocked telescopic fingers move towards the direction close to the arc-shaped base, and the blocked telescopic fingers are shortened, forming a local avoidance space to avoid the adjacent tomatoes or branches, ensuring that the distal phalanxes of each telescopic finger can clamp the target tomato, and then realizing the complete envelope of the target tomato, improving the picking success rate, and at the same time avoiding the collision damage to other tomatoes except the target tomato; further, the proximal phalanx of each telescopic finger in the telescopic finger forms a sliding pair with a chute opened on the arc-shaped base, and is connected with the arc-shaped base through an elastic rope. When the two telescopic fingers are closed, when the distal phalanxes of each telescopic finger contact the irregular surface of the target tomato, the distal phalanxes of each telescopic finger drive the proximal phalanxes to move outwards along the corresponding chutes, and each elastic rope is further stretched, so that the distal phalanxes of each telescopic finger can better fit the irregular surface of the target tomato, avoiding the phenomenon of damage to the target tomato caused by excessive local pressure, further reducing the fruit damage rate, and having a relatively fast response speed; in addition, when the target tomato is in the envelope cavity formed by the arc-shaped baffles on each distal phalanx, the external branches are isolated and it is difficult to damage the target tomato, further reducing the fruit damage rate.

[0018] 2. In the present invention, elastic ropes with different stiffness coefficients can be replaced according to the hardness characteristics of different tomato varieties, so as to adjust the resilience of the elastic ropes to adjust the clamping force of the telescopic fingers on the target tomato, while realizing the stable grasping of tomatoes with different hardnesses, and avoiding the damage to the epidermis of tomatoes with different hardnesses. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0020] Figure 2 is a schematic diagram of the structure of the present invention after removing part of the outer shell and the distal phalanxes on one of the telescopic fingers;

[0021] Figure 3 is a schematic diagram of the structure of the driving mechanism in the present invention;

[0022] Figure 4 Structural schematic diagram of two telescopic gripper fingers in the present invention;

[0023] Figure 5 is Figure 4 top view of;

[0024] Figure 6 Structural schematic diagram of the finger plate in the present invention;

[0025] Figure 7 Cross-sectional view of the telescopic finger after removing the steel wire rope in the present invention. Specific implementation manner

[0026] The present invention will be further described below with reference to the accompanying drawings.

[0027] As Figure 1 shown, a tomato picking manipulator with self-adaptive telescopic fingers in the present invention includes a housing 1, a driving mechanism and telescopic gripper fingers.

[0028] As Figure 2 and Figure 3 shown in the figure, the driving mechanism includes a gear 21, a connecting rod 5, a finger support 6 and a guide rod group; the gear 21 is placed inside the housing 1, forms a rotating pair with the housing 1, and is driven by a servo motor 2, and the servo motor 2 is controlled by a controller; two finger supports 6 are arranged on both sides of the gear 21 inside the housing 1; both of the two finger supports 6 form a sliding pair with the housing 1, and integrally formed racks 61 are arranged on the inner sides of the two finger supports 6, and both of the two racks 61 are engaged with the gear 21; connecting rods 5 are fixed on both of the two finger supports 6, and two telescopic gripper fingers are arranged symmetrically on the two connecting rods 5, and the symmetry center plane of the two telescopic gripper fingers is perpendicular to the rack 61.

[0029] As Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7As shown in the figure, the telescopic clamping fingers include a finger plate 3 and telescopic fingers 4. The finger plate 3 includes an arc-shaped base, pulleys 35 and rope buckles 36; the arc-shaped base is fixed to the corresponding connecting rod 5, and four chutes 32 are arranged at equal intervals along the circumferential direction at the outer end of the arc-shaped base, and each chute 32 is arranged radially; a through hole 33 is provided at the inner end of each chute 32, an outer cover plate 31 is fixed at the outer end, and four pulleys 35 are hinged to the inner side of the arc-shaped base and arranged at equal intervals along the circumferential direction and aligned with the respective through holes 33 respectively, and four rope buckles 36 are fixed to the outer side and arranged at equal intervals along the circumferential direction and aligned with the respective pulleys 35 respectively. The telescopic finger 4 includes a proximal phalanx 41, a distal phalanx 42 and a steel wire rope 43; the proximal phalanx 41 is embedded in a straight hole provided on the distal phalanx 42 to form a sliding pair with the straight hole, and a return spring 44 is arranged coaxially in the straight hole. One end of the steel wire rope 43 is fixed to the end of the straight hole away from the proximal phalanx 41, and the other end passes through the return spring 44 and is fixed to the proximal phalanx 41. The steel wire rope 43 is used to prevent the distal phalanx 42 from separating from the proximal phalanx 41; an integrally formed arc-shaped baffle 422 is provided at one end of the inner side of the distal phalanx 42 close to the proximal phalanx 41. An arc-shaped base is provided with a telescopic finger 4 on each chute 32. The proximal phalanx 41 of each telescopic finger 4 is perpendicular to the arc-shaped base. One end of each proximal phalanx 41 away from the distal phalanx 42 forms a sliding pair with the corresponding chute 32 and is fixed to one end of an elastic rope 34. The other end of each elastic rope 34 passes through the corresponding through hole 33, bypasses the corresponding pulley 35 and is fixed to the corresponding rope buckle 36. Among them, the arc-shaped baffles 422 of all the telescopic fingers 4 together prevent the tomatoes from falling and avoid damage to the tomatoes caused by the branches when the telescopic clamping fingers clamp and move the tomatoes. Each return spring 44 is in a compressed state, and each elastic rope 34 is in a stretched state. In the initial state, each steel wire rope 43 is in a tensioned state.

[0030] As a preferred embodiment, the housing of the servo motor 2 is fixed within the outer shell 1, and the output shaft is fixed to the gear 21.

[0031] As a preferred embodiment, two guide rod groups are symmetrically arranged on both sides of the gear 21 within the outer shell 1. The guide rod group consists of a plurality of guide rods 7 arranged at intervals. Each guide rod 7 is arranged in parallel, perpendicular to the gear 21, and is fixed to the outer shell 1. Two through hole groups are symmetrically arranged at both ends of each finger bracket 6. The through hole group consists of a plurality of through holes 62 arranged at intervals. Each pair of aligned through holes 62 at both ends of each finger bracket 6 are fixed to both ends of a sleeve 51, and each sleeve 51 on each finger bracket 6 is sleeved on a guide rod 7 of the same-side guide rod group to form a sliding pair with the corresponding guide rod 7; each connecting rod 5 is fixed to each sleeve 51 on the corresponding finger bracket 6.

[0032] More preferably, a guide rod 2 is also fixed within the outer shell 1 between the two guide rod groups and is parallel to the guide rod 7. Both connecting rods 5 form sliding pairs with the guide rod 2.

[0033] As a preferred embodiment, a counterbore 421 is provided at one end of the straight hole away from the proximal phalanx 41. A through hole three 411 is provided on the proximal phalanx 41. One end of the steel wire rope 43 is fixed to the counterbore 421, the other end passes through the return spring 44, and then passes into the through hole three 411 and is fixed to the through hole three 411.

[0034] As a preferred embodiment, a V-shaped wire groove 351 is provided on the pulley 35; each elastic rope 34 bypasses the V-shaped wire groove 351 of the corresponding pulley 35 and is fixed to the corresponding rope buckle 36.

[0035] The picking method of a tomato picking manipulator with self-adaptive telescopic fingers according to the present invention is as follows:

[0036] Install the housing 1 on the robotic arm. In the initial state, the two telescopic fingers are in a separated state; the robotic arm drives the housing 1 to move towards the position of the target tomato, so that the target tomato is located within the envelope space formed by each arc-shaped baffle 422 on the two telescopic fingers (the position of the target tomato and whether the target tomato is within the envelope space can be identified by a camera). At the same time, if the adjacent tomatoes or branches of the target tomato touch the end of some distal phalanges 42, some of the distal phalanges 42 are blocked, and the blocked distal phalanges 42 move towards the arc-shaped base, the corresponding return springs 44 are further compressed, and the corresponding steel wire ropes 43 are relaxed, while the unblocked distal phalanges 42 remain unchanged; then the controller controls the servo motor 2 to drive the gear 21 to rotate forward by a preset angle. The gear 21 drives the two finger brackets 6 to move towards each other through the two racks 61. The two finger brackets 6 drive the two arc-shaped bases to move towards each other through the two connecting rods 5, and further drive the two telescopic fingers to move towards each other to close and envelope the target tomato. And when each distal phalanx 42 contacts the irregular surface of the target tomato, each distal phalanx 42 drives the proximal phalanx 41 to move outwards along the corresponding chute 32, and each elastic rope 34 is further stretched; then the robotic arm drives the housing 1 to rotate around its own central axis to twist off the target tomato. The robotic arm then drives the housing 1 to move to the collection basket. The blocked distal phalanges 42 move away from the arc-shaped base to their original positions under the restoring force of the corresponding return springs 44; the controller controls the servo motor 2 to drive the gear 21 to rotate backward by a preset angle. The gear 21 drives the two finger brackets 6 to move away from each other through the two racks 61. The two finger brackets 6 drive the two arc-shaped bases to move away from each other through the two connecting rods 5, so that the two telescopic fingers are unfolded to their original positions. At the same time, each distal phalanx 42 is separated from the target tomato, and the target tomato falls into the collection basket. Each elastic rope 34 pulls each proximal phalanx 41 to move inwards to its original position, thus completing the picking work of the target tomato.

Claims

1. A tomato picking manipulator with self - adaptive telescopic fingers, comprising a housing and a driving mechanism, characterized in that: It further includes two telescopic clamping fingers driven to open and close by a driving mechanism; the telescopic clamping fingers include finger plates and telescopic fingers; the finger plates include arc-shaped bases, pulleys and rope buckles, the arc-shaped bases and the housing form a sliding pair, the outer ends of the arc-shaped bases are provided with n chutes arranged equidistantly in the circumferential direction, n≥4, and each chute is arranged radially, a through hole one is opened at the inner end of each chute, an outer cover plate is fixed at the outer end, and n pulleys arranged equidistantly in the circumferential direction and respectively aligned with the through holes one are hinged inside the arc-shaped bases, and n rope buckles arranged equidistantly in the circumferential direction and respectively aligned with the pulleys are fixed outside; the telescopic fingers include proximal phalanges, distal phalanges and steel wire ropes, the straight holes opened on the proximal phalanges and the distal phalanges form a sliding pair, and a return spring is arranged coaxially in the straight holes, one end of the steel wire rope is fixed to the end of the straight hole far from the proximal phalanx, the other end passes through the return spring and is fixed to the proximal phalanx, and an integrally formed arc-shaped baffle is arranged at one end of the inner side of the distal phalanx close to the proximal phalanx; one telescopic finger is arranged on the arc-shaped base at each chute, the proximal phalanx of each telescopic finger is perpendicular to the arc-shaped base, one end of each proximal phalanx far from the distal phalanx forms a sliding pair with the corresponding chute and is fixed to one end of an elastic rope, the other end of each elastic rope passes through the corresponding through hole one, bypasses the corresponding pulley and is fixed to the corresponding rope buckle; Among them, each return spring is in a compressed state, each elastic rope is in a stretched state, and in the initial state, each steel wire rope is in a tensioned state.

2. The tomato picking manipulator with self - adaptive telescopic fingers according to claim 1, wherein: The driving mechanism includes a gear, a connecting rod, a finger bracket and a guide rod group, the gear is placed inside the housing, forms a rotating pair with the housing, and is driven by a steering gear, the steering gear is controlled by a controller, two finger brackets are arranged on both sides of the gear inside the housing, both finger brackets form a sliding pair with the housing, and integrally formed racks are arranged on the inner sides of both finger brackets, both racks are engaged with the gear, and connecting rods are fixed on both finger brackets; the arc-shaped bases of the two telescopic clamping fingers are respectively fixed to the two connecting rods, and the symmetry center planes of the two telescopic clamping fingers are perpendicular to the racks.

3. The tomato picking manipulator with self - adaptive telescopic fingers according to claim 2, characterized in that: The housing of the steering gear is fixed inside the housing, and the output shaft is fixed to the gear.

4. The tomato picking manipulator with adaptively telescopic fingers according to claim 2, wherein: Two symmetrically arranged guide rod groups are arranged on both sides of the gear inside the housing, the guide rod group is composed of a plurality of guide rods one arranged at intervals, each guide rod one is arranged in parallel and perpendicular to the gear, and is fixed to the housing, two through hole groups are symmetrically arranged at both ends of each finger bracket, the through hole group is composed of a plurality of through holes two arranged at intervals, and the two aligned through holes two at both ends of each finger bracket are fixed to both ends of a sleeve, and each sleeve on each finger bracket is sleeved on a guide rod one of the guide rod group on the same side and forms a sliding pair with the corresponding guide rod one; each connecting rod is fixed to each sleeve on the corresponding finger bracket.

5. The tomato picking manipulator with adaptively telescopic fingers according to claim 4, characterized in that: A guide rod two parallel to the guide rod one is further fixed inside the housing between the two guide rod groups, and both connecting rods form a sliding pair with the guide rod two.

6. The tomato picking manipulator with adaptively telescopic fingers according to claim 1, characterized in that: A counterbore is opened at the end of the straight hole far from the proximal phalanx, a through hole three is opened on the proximal phalanx, one end of the steel wire rope is fixed to the counterbore, the other end passes through the return spring and penetrates into the through hole three and is fixed to the through hole three.

7. A tomato picking manipulator with adaptively telescopic fingers according to claim 1, characterized in that: A V-shaped wire groove is opened on the pulley; each elastic rope bypasses the V-shaped wire groove of the corresponding pulley and is fixed to the corresponding rope buckle.

8. The picking method of a tomato picking manipulator with adaptively telescopic fingers according to any one of claims 1 to 7, characterized in that: Specifically as follows: Install the outer shell on the robotic arm. In the initial state, the two telescopic clamping fingers are separated. The robotic arm drives the outer shell to move towards the position of the target tomato, so that the target tomato is located within the envelope space formed by the arc-shaped baffles on the two telescopic clamping fingers. At the same time, if the adjacent tomatoes or branches of the target tomato touch part of the end of the distal phalanx, some of the distal phalanges are blocked. The blocked distal phalanges move towards the arc-shaped base, and the corresponding return springs are further compressed, and the corresponding steel wire ropes are relaxed, while the unblocked distal phalanges remain unchanged. Then the driving mechanism drives the two arc-shaped bases to move towards each other, and further drives the two telescopic clamping fingers to move towards each other, so that the two telescopic clamping fingers close to envelope the target tomato. And when each distal phalanx contacts the irregular surface of the target tomato, each distal phalanx drives the proximal phalanx to move outwards along the corresponding chute, and the elastic ropes are further stretched. Then the robotic arm drives the outer shell to rotate around its own central axis to twist off the target tomato. The robotic arm then drives the outer shell to move above the collection basket. The blocked distal phalanges move away from the arc-shaped base to their original positions under the restoring force of the corresponding return springs. The driving mechanism drives the two arc-shaped bases to move away from each other, so that the two telescopic clamping fingers expand to their original positions. At the same time, each distal phalanx is separated from the target tomato, and the target tomato falls into the collection basket. Each elastic rope pulls each proximal phalanx to move inwards to its original position, thus completing the picking work of the target tomato.

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