阅读说明：本技术 番茄枝叶修剪装置及其修剪方法 (Tomato branch and leaf trimming device and trimming method thereof ) 是由 梁喜凤 杨铭涛 花瑞 楼玉红 花诗影 王永维 于 2019-10-24 设计创作，主要内容包括：本发明公开了一种用于番茄枝叶修剪装置及其修剪方法,属于农用机器人领域。本发明所述装置包括圆盘、夹取机构、剪切机构和外壳。本装置通过直流电机同时带动夹取和修剪机构完成工作；夹取机构通过电机带动两个反向转动齿轮转动,从而带动夹爪反向转动实现对枝叶夹取,同时,刀刃沿安装固定圆盘上的两圆弧型轨道旋转实现剪切。本发明克服了传统剪裁的末端执行器在剪裁枝叶时,枝叶容易晃动的问题,且该装置可靠性高,控制操作简单,效率高,通用性高,不仅适合于番茄的枝叶修剪,也同样适合其他类似农作物的职业修剪,且人工劳动强度小。(The invention discloses a tomato branch and leaf trimming device and a tomato branch and leaf trimming method, and belongs to the field of agricultural robots. The device comprises a disc, a clamping mechanism, a shearing mechanism and a shell. The device simultaneously drives the clamping and trimming mechanism to complete work through the direct current motor; the clamping mechanism drives the two reverse rotating gears to rotate through the motor, so that the clamping jaws are driven to rotate reversely to clamp branches and leaves, and meanwhile, the cutting edges rotate along the two arc-shaped tracks on the fixed disc to realize shearing. The device solves the problem that branches and leaves are easy to shake when the traditional end effector is used for cutting the branches and leaves, has high reliability, simple control operation, high efficiency and high universality, is suitable for pruning the branches and leaves of tomatoes and also suitable for the professional pruning of other similar crops, and has low labor intensity.)

1. The tomato branch and leaf pruning device is characterized by comprising a disc (1), a clamping mechanism, a shearing mechanism and a shell (16), wherein two concentric circular arc-shaped tracks are hollowed out along the circumference of the disc (1) and respectively comprise a circular arc-shaped inner track (14) and a circular arc-shaped outer track (13), and the shell (16) is fixedly connected with the bottom of the disc (1);

the clamping mechanism comprises a driving clamping jaw (111), a driven clamping jaw (112), a driving gear (4), a driven gear (3), a driving shaft (7), a driven shaft (2) and a direct current motor (9); an output shaft of the direct current motor (9) is fixedly connected with one end of a driving shaft (7) through a coupler (8), the other end of the driving shaft (7) sequentially penetrates through the center of the end face of the driving gear (4) and the eccentric position of the disc (1) to form a revolute pair with the disc (1), and the other end of the driving shaft (7) is fixedly connected with a driving clamping jaw (111); one end of the driven shaft (2) is installed on the shell (16) and forms a revolute pair with the shell (16), the other end of the driven shaft sequentially penetrates through the center of the end face of the driven gear (3) and the eccentric position of the disc (1) and forms a revolute pair with the disc (1), and the other end of the driven shaft (2) is fixedly connected with the driven clamping jaw (112); the driving gear (4) is in meshed transmission connection with the driven gear (3), and the driving gear (4) and the driven gear (3) are fixedly connected with the driving shaft (7) and the driven shaft (2) through keys respectively; the driving clamping jaw (111) and the driven clamping jaw (112) are driven by a direct current motor (9) to switch a clamping state and a separating state;

the shearing mechanism comprises a driving blade (12), a driven blade (10), a driving slide rod (51), a driven slide rod (52), a driving sleeve rod (61) and a driven sleeve rod (62), one end of the driving sleeve rod (61) is fixedly connected with the driving shaft (7), the other end of the driving sleeve rod is slidably connected with the driving slide rod (51), and the tail end of the driving slide rod (51) is fixedly connected with an installation part of the driving blade (12); one end of the driven loop bar (62) is fixedly connected with the driven shaft (2), the other end of the driven loop bar is connected with the driven slide bar (52) in a sliding manner, and the tail end of the driven slide bar (52) is fixedly connected with the mounting part of the driven blade (10); the driving blade (12) and the driven blade (10) are respectively positioned in the two arc-shaped tracks of the disc (1) and form a sliding pair with the tracks to be connected, and the blade parts of the blades extend out of the upper disc surface of the disc (1); initiative blade (12) and driven blade (10) open and shut along two circular arc tracks under direct current motor (9) drive, and are in initiative clamping jaw (111) and driven clamping jaw (112) are in the detached state, and initiative blade (12) and driven blade (10) also are in the detached position initiative clamping jaw (111) and driven clamping jaw (112) are in and press from both sides the state of getting under, and the cutting part dislocation of initiative blade (12) and driven blade (10) overlaps, forms the shearing state.

2. The tomato branch and leaf trimming device as claimed in claim 1, characterized in that the circle radius of the circular arc inner track (14) and the circular arc outer track (13) is different, so that the driving blade (12) and the driven blade (10) are only overlapped in a staggered way but do not interfere with each other during the rotation along the tracks.

3. The tomato branch and leaf trimming device as claimed in claim 1, wherein the driving loop bar (61) and the driven loop bar (62) are in the same form, one end of the loop bar is provided with a cylindrical connecting hole for connecting and fixing with a shaft, the other end of the loop bar is a rectangular hollow structure, one side of the rectangular hollow structure is provided with two parallel sliding grooves, the driving slide bar (51) and the driven slide bar (52) are respectively installed in the rectangular hollow structures of the driving loop bar (61) and the driven loop bar (62), and form a sliding pair for limiting falling through a limiting piece and the parallel sliding grooves.

4. Tomato branch and leaf trimming device according to claim 1, characterized in that the driving blade (12) and the driven blade (10) are identical in form and are both arc-shaped structures, the edge parts of which are provided with side edges.

5. The tomato branch and leaf trimming device according to claim 1, characterized in that the driving clamping jaw (111) and the driven clamping jaw (112) are in the same form, and are both semi-cylinders, and when the two semi-cylinders are in a separated state, the respective planar side walls are oppositely arranged.

6. Tomato branch and leaf trimming device according to claim 1, characterized in that the dc motor (9) is fixed to a bracket in the middle of the housing (16).

7. Tomato branch and leaf trimming device according to claim 1, characterized in that the central radial angles of the driving blade (12) and the driving jaw (111) and the driven blade (10) and the driven jaw (112) are both 15 °.

8. A method for pruning tomato branches and leaves according to any one of claims 1 to 7, characterized by comprising the following steps:

1) resetting the system: the driving clamping jaw (111) and the driven clamping jaw (112) and the driving blade (12) and the driven blade (10) are in a separated state;

2) the pruning device is moved to the position of leaves to be pruned through a mechanical arm, so that a driving clamping jaw (111) and a driven clamping jaw (112), and a driving blade (12) and a driven blade (10) are respectively positioned at two sides of the leaves;

3) the direct current motor (9) is controlled to work and rotate, the driving gear (4) is driven to rotate under the action of the coupler (8) and the driving shaft (7), the driven gear (3) is connected with the driving gear (4) in a meshing transmission mode and rotates along with the driving gear, so that the driving clamping jaw (111) and the driven clamping jaw (112) are driven to synchronously rotate in the opposite direction, and the distance between the driving clamping jaw and the driven clamping jaw is reduced to clamp leaves to be pruned; meanwhile, a driving blade (12) and a driven blade (10) which are connected with the driving gear (4) and the driven gear (3) rotate synchronously and reversely, and after the leaves to be pruned are clamped, the two blades are overlapped in a staggered manner, so that the cutting of the leaves is realized;

4) keeping the driving clamping jaw (111) and the driven clamping jaw (112) in a clamping state, and moving the cut branches and leaves clamped by the pruning device to a specified position through a mechanical arm;

5) controlling a direct current motor (9) to rotate reversely, so that a driving clamping jaw (111) and a driven clamping jaw (112), and a driving blade (12) and a driven blade (10) are gradually separated along with the rotation, and the clamped cut branches and leaves are placed at a designated position;

6) and (5) repeating the steps 1) to 5) aiming at the next branch and leaf to be trimmed.

Technical Field

The invention belongs to the field of agricultural robots, and particularly relates to a tomato branch and leaf trimming device which is suitable for solving the problem of automatic trimming of tomato branches and leaves.

Background

No matter be crops or landscape plant, all need regular repairment, and the degree of automation of present domestic tomato branch and leaf trimming means is lower, and many automatic arm structures of tailorring tomato branch and leaf are also more complicated, and during the pruning, target tomato branch and leaf rocks easily, and then leads to pruning incompletely or even pruning failure, and after pruning, no matter be the meadow or crops or trees, all can have a lot of branches and leaves of pruning, and these branches and leaves of pruning still must be collected and cleared up by manual work or other equipment. This makes the traditional tomato branch and leaf trimming device of original can not satisfy the demand of pruning the tomato branch and leaf in the present agriculture completely. Therefore, it is highly desirable to design a new tomato branch and leaf trimming device, which can simultaneously clamp and trim two steps.

Disclosure of Invention

The invention aims to solve the problem that a common tomato branch and leaf trimmer cannot stably and reliably trim the branches and leaves when trimming the tomato branches and leaves, and provides a device for clamping the tomato branches and leaves.

The invention adopts the following specific technical scheme:

a tomato branch and leaf pruning device comprises a disc, a clamping mechanism, a shearing mechanism and a shell, wherein two concentric circular arc-shaped tracks are hollowed out at the edge of the disc along the circumference and respectively comprise a circular arc-shaped inner track and a circular arc-shaped outer track, and the shell is fixedly connected with the bottom of the disc;

the clamping mechanism comprises a driving clamping jaw, a driven clamping jaw, a driving gear, a driven gear, a driving shaft, a driven shaft and a direct current motor; an output shaft of the direct current motor is fixedly connected with one end of a driving shaft through a coupler, the other end of the driving shaft sequentially penetrates through the center of the end face of the driving gear and the eccentric position of the disc to form a revolute pair with the disc, and the other end of the driving shaft is fixedly connected with the driving clamping jaw; one end of the driven shaft is installed on the shell and forms a rotating pair with the shell, the other end of the driven shaft sequentially penetrates through the center of the end face of the driven gear and the eccentric position of the disc and forms a rotating pair with the disc, and the other end of the driven shaft is fixedly connected with the driven clamping jaw; the driving gear is in meshing transmission connection with the driven gear, and the driving gear and the driven gear are respectively fixedly connected with the driving shaft and the driven shaft through keys; the driving clamping jaw and the driven clamping jaw are driven by a direct current motor to switch a clamping state and a separating state;

the shearing mechanism comprises a driving blade, a driven blade, a driving sliding rod, a driven sliding rod, a driving loop bar and a driven loop bar, wherein one end of the driving loop bar is fixedly connected with the driving shaft, the other end of the driving loop bar is connected with the driving sliding rod in a sliding manner, and the tail end of the driving sliding rod is fixedly connected with the mounting part of the driving blade; one end of the driven loop bar is fixedly connected with the driven shaft, the other end of the driven loop bar is connected with the driven slide bar in a sliding manner, and the tail end of the driven slide bar is fixedly connected with the mounting part of the driven blade; the driving blade and the driven blade are respectively positioned in the two arc-shaped tracks of the disc and form a sliding pair with the tracks to be connected, and the blade part of the blade extends out of the upper disc surface of the disc; initiative blade and driven blade open and shut along two circular arc tracks under the direct current motor drive, and be in under initiative clamping jaw and the driven clamping jaw are in the detached state, initiative blade and driven blade also are in the detached position under initiative clamping jaw and the driven clamping jaw are in to press from both sides and get the state, and the cutting part dislocation of initiative blade and driven blade overlaps, forms the shear state.

Preferably, the radii of circles of the circular arc inner rail and the circular arc outer rail are different, so that the driving blade and the driven blade are only overlapped in a staggered mode but do not interfere with each other in the process of rotating along the rails.

Preferably, the driving loop bar and the driven loop bar are in the same form, one end of the loop bar is provided with a cylindrical connecting hole for connecting and fixing with a shaft, the other end of the loop bar is of a rectangular hollow structure, one side of the rectangular hollow structure is provided with two parallel sliding chutes, and the driving sliding bar and the driven sliding bar are respectively installed in the rectangular hollow structures of the driving loop bar and the driven loop bar and form a sliding pair for limiting falling through a limiting piece and the parallel sliding chutes.

Preferably, the driving blade and the driven blade are in the same form and are both arc-shaped structures, and the edge parts of the driving blade and the driven blade are provided with side edges.

Preferably, the driving clamping jaw and the driven clamping jaw are in the same form and are both semi-cylinders, and when the two semi-cylinders are in a separated state, the planar side walls of the two semi-cylinders are opposite.

Preferably, the direct current motor is fixed on a bracket in the middle of the shell.

Preferably, the central radial included angles of the driving blade and the driving clamping jaw and the central radial included angles of the driven blade and the driven clamping jaw are 15 degrees.

Another object of the present invention is to provide a method for trimming the tomato branches and leaves trimming device, comprising the following steps:

1) resetting the system: the driving clamping jaw and the driven clamping jaw, and the driving blade and the driven blade are in a separated state;

2) the pruning device is moved to the position of leaves to be pruned through a mechanical arm, so that the driving clamping jaw and the driven clamping jaw, and the driving blade and the driven blade are respectively positioned at two sides of the leaves;

3) the direct current motor is controlled to work and rotate, the driving gear is driven to rotate under the action of the coupler and the driving shaft, the driven gear is connected with the driving gear in a meshing transmission mode and rotates along with the driving gear, the driving clamping jaw and the driven clamping jaw are driven to synchronously rotate in the opposite direction, and the distance between the driving clamping jaw and the driven clamping jaw is reduced to clamp leaves to be pruned; meanwhile, the driving blade and the driven blade which are connected with the driving gear and the driven gear also synchronously rotate reversely, and the two blades are overlapped in a staggered way after the branches and leaves to be cut are clamped, so that the branches and leaves are cut;

4) keeping the driving clamping jaw and the driven clamping jaw in a clamping state, and moving the sheared branches and leaves clamped by the trimming device to a designated position through a mechanical arm;

5) controlling the direct current motor to rotate reversely, so that the driving clamping jaw and the driven clamping jaw, and the driving blade and the driven blade are gradually separated along with the rotation, and the clamped and cut branches and leaves are placed at a designated position;

6) and (5) repeating the steps 1) to 5) aiming at the next branch and leaf to be trimmed.

Compared with the prior art, the invention has the following beneficial effects:

the device solves the problem that branches and leaves are easy to shake when the traditional end effector is used for cutting the branches and leaves, has high reliability, simple control operation, high efficiency and high universality, is suitable for pruning the branches and leaves of tomatoes and also suitable for the professional pruning of other similar crops, and has low labor intensity. The device is used for the automatic clamp of tomato branch and leaf to get the pruning, can be 15 through the radial contained angle of fixed circular knife piece and clamping jaw, makes the device can realize getting in step and carry out of two steps of pruning.

Drawings

FIG. 1 is a schematic view of the internal structure of the present invention;

FIG. 2 is a schematic view of a jaw and blade configuration of the present invention;

FIG. 3 is a schematic view of a pantograph linkage of the present invention;

FIG. 4 is a schematic view of a disk of the present invention;

FIG. 5 is a general schematic of the present invention;

wherein: the disc type rotary cutter comprises a disc 1, a driven shaft 2, a driven gear 3, a driving gear 4, a driving slide rod 51, a driven slide rod 52, a driving sleeve rod 61, a driven sleeve rod 62, a driving shaft 7, a coupler 8, a direct current motor 9, a driven blade 10, a driving clamping jaw 111, a driven clamping jaw 112, a driving blade 12, an arc-shaped outer rail 13, an arc-shaped inner rail 14, a screw hole 15 and a shell 16.

Detailed Description

The invention will be further elucidated and described with reference to the drawings and the detailed description. The technical features of the embodiments of the present invention can be combined correspondingly without mutual conflict.

As shown in fig. 1 to 5, a tomato branch and leaf pruning device comprises a disc 1, a clamping mechanism, a shearing mechanism and a shell 16, wherein two concentric circular arc-shaped tracks are hollowed out along the circumference of the disc 1, and are respectively a circular arc-shaped inner track 14 and a circular arc-shaped outer track 13. The circle radius of the circular arc inner track 14 is different from that of the circular arc outer track 13, so that the driving blade 12 and the driven blade 10 are only overlapped in a staggered mode but do not interfere with each other in the process of rotating along the tracks. However, the difference between the radii of the two tracks should not be too large so as to prevent the follow-up blade from being close to each other. The disc 1 is provided with a plurality of screw holes 15, and the shell 16 is fixedly connected with the bottom of the disc 1 through screws. The housing 16 functions as part of the transmission for the bale pick-up mechanism and the shearing mechanism. The following describes in detail the specific structural forms of the gripping mechanism and the shearing mechanism.

The clamping mechanism comprises a clamping jaw 11 (divided into a driving clamping jaw 111 and a driven clamping jaw 112), a driving gear 4, a driven gear 3, a driving shaft 7, a driven shaft 2 and a direct current motor 9. The direct current motor 9 is fixed on a bracket in the middle of the shell 16. An output shaft of the direct current motor 9 is fixedly connected with one end of a driving shaft 7 through a coupler 8, the other end of the driving shaft 7 sequentially penetrates through the center of the end face of the driving gear 4 and the eccentric position of the disc 1 and forms a revolute pair with the disc 1, and the other end of the driving shaft 7 penetrates through the disc 1 and then is fixedly connected with the driving clamping jaw 111 to drive the driving clamping jaw 111 to rotate. Similarly, one end of the driven shaft 2 is installed on the housing 16 and forms a revolute pair with the housing 16, the other end of the driven shaft sequentially penetrates through the center of the end face of the driven gear 3 and the eccentric position of the disc 1 and forms a revolute pair with the disc 1, and the other end of the driven shaft 2 penetrates through the disc 1 and then is fixedly connected with the driven clamping jaw 112 to drive the driving clamping jaw 111 to rotate. The driving gear 4 is in meshed transmission connection with the driven gear 3, and the driving gear 4 and the driven gear 3 are fixedly connected with the driving shaft 7 and the driven shaft 2 through keys respectively and rotate synchronously along with the shafts. In addition, two telescopic connecting rods consisting of a sliding rod 5 and a loop bar 6 in the subsequent shearing mechanism are required to be fixed on the driving shaft 7 and the driven shaft 2 respectively. The driving jaw 111 and the driven jaw 112 mainly function to clamp branches and leaves to be trimmed, and therefore, the form thereof needs to be ensured to be capable of switching between a clamping state and a separating state under the driving of the dc motor 9. In this embodiment, as shown in fig. 2, the driving jaw 111 and the driven jaw 112 are in the same form and are both half cylinders, the bottom surface of the half cylinder is connected to the shaft, and the side surface is divided into two parts, i.e., an arc-shaped cylindrical surface and a planar side wall. In order to ensure that the clamping state and the separating state can be realized, when the two semi-cylinders are in the separating state, the respective plane-shaped side walls are oppositely arranged, and a certain distance exists between the two semi-cylinders, so that the branches and leaves to be pruned can enter; when the two semi-cylinders rotate synchronously and reversely, the arc-shaped cylindrical surfaces of the two semi-cylinders gradually approach to each other, so that the distance between the two semi-cylinders is reduced, and branches and leaves to be trimmed are clamped. Therefore, the distance between the two semi-cylinders and the radius of the cylinder need to be reasonably designed to meet the use requirement.

In addition, the shearing mechanism comprises a driving blade 12, a driven blade 10, a driving slide rod 51, a driven slide rod 52, a driving sleeve rod 61 and a driven sleeve rod 62, one end of the driving sleeve rod 61 is fixedly connected with the driving shaft 7, the other end of the driving sleeve rod is connected with the driving slide rod 51 in a sliding mode, and the tail end of the driving slide rod 51 is fixedly connected with a mounting part of the driving blade 12. Similarly, one end of the driven loop bar 62 is fixedly connected with the driven shaft 2, the other end is connected with the driven slide bar 52 in a sliding manner, and the tail end of the driven slide bar 52 is fixedly connected with the mounting part of the driven blade 10. In this embodiment, as shown in fig. 3, the driving loop bar 61 and the driven loop bar 62 have the same form, one end of the loop bar is provided with a cylindrical connecting hole for connecting and fixing with a shaft, the other end of the loop bar is a rectangular hollow structure, one side of the rectangular hollow structure is provided with two parallel sliding chutes, the driving slide bar 51 and the driven slide bar 52 are rectangular blocks and are respectively installed in the rectangular hollow structures of the driving loop bar 61 and the driven loop bar 62, and can slide in the loop bar, so as to form a telescopic connecting rod, which can sufficiently adjust the length between the blade and the shaft, thereby ensuring that the driving blade 12 and the driven blade 10 can be smoothly driven even if they are eccentrically installed. In addition, in the telescopic connecting rod structure, a limiting part is required to be designed, so that the sliding rod cannot fall off from the parallel sliding groove in the loop bar in the sliding process.

The driving blade 12 and the driven blade 10 are respectively positioned in two arc-shaped tracks of the disc 1 and form a sliding pair connection with the tracks, and the blade parts of the blades extend out of the upper disc surface of the disc 1. In this embodiment, the driving blade 12 and the driven blade 10 have the same form and are both arc-shaped structures, the edge portions thereof are provided with side edges, and the edge portions are synchronously attached to form a shearing state similar to scissors when the driving blade and the driven blade approach each other.

In the invention, the driving blade 12 and the driven blade 10 are driven by the direct current motor 9 to open and close along two circular arc tracks, so that the opening and closing are synchronous with the actions of the driving clamping jaw 111 and the driven clamping jaw 112. In order to ensure that the pruning device can clamp and prune branches and leaves to be pruned, the arrangement positions of all the components on the disc 1 need to be reasonably configured. In the separated state of the driving jaw 111 and the driven jaw 112, the driving blade 12 and the driven blade 10 should be in the separated position and keep a certain distance for the leaves to be pruned to enter. And under the state that the driving clamping jaw 111 and the driven clamping jaw 112 are driven by the direct current motor 9 to gradually approach each other and then the branches and leaves to be trimmed are clamped, the cutting parts of the driving blade 12 and the driven blade 10 are also staggered and overlapped to form a shearing state, and the branches and leaves to be trimmed are sheared. It should be noted, however, that the clamping and trimming are not completely synchronized, and the best way is to clamp the clip first and then trim it. Therefore, the radial included angles of the centers of the driving blade 12 and the driving clamping jaw 111 and the radial included angles of the centers of the driven blade 10 and the driven clamping jaw 112 can be set to be 15 °, that is, when the driving clamping jaw 111 and the driven clamping jaw 112 are already in a clamping state, the distance between the cutting parts of the driving blade 12 and the driven blade 10 is 15 ° and the central angles are not completely overlapped, the two blades are continuously driven to rotate at the moment, trimming can be completed under the condition that branches and leaves are fixed, and trimming failure caused by shaking is avoided.

Based on the tomato branch and leaf trimming device, the invention also provides a tomato branch and leaf trimming method, which comprises the following steps:

1) resetting the system: the driving jaw 111 and the driven jaw 112, and the driving blade 12 and the driven blade 10 are all in a separated state, and branches and leaves are provided to enter the passage.

2) The pruning device is moved to the position of the leaf to be pruned by the mechanical arm, so that the driving clamping jaw 111 and the driven clamping jaw 112, and the driving blade 12 and the driven blade 10 are respectively positioned at two sides of the leaf.

3) The direct current motor 9 is controlled to work and rotate, the driving gear 4 is driven to rotate under the action of the coupler 8 and the driving shaft 7, the driven gear 3 is connected with the driving gear 4 in a meshing transmission mode and rotates along with the driving gear, so that the driving clamping jaw 111 and the driven clamping jaw 112 are driven to synchronously rotate in the opposite direction, and the distance between the driving clamping jaw and the driven clamping jaw is reduced to clamp leaves to be pruned; meanwhile, the driving blade 12 and the driven blade 10 which are connected with the driving gear 4 and the driven gear 3 also synchronously and reversely rotate, and after the branches and leaves to be cut are clamped, the two blades are staggered and overlapped, so that the branches and leaves are cut. In this step, the aforementioned central angle of 15 ° is preferably set to ensure that the clipping is performed first and then the trimming is performed.

4) The cut branches and leaves gripped by the trimming device are moved to a specified position by the robot arm while holding the driving jaw 111 and the driven jaw 112 in the gripping state.

5) The direct current motor 9 is controlled to rotate reversely, so that the driving clamping jaw 111 and the driven clamping jaw 112, and the driving blade 12 and the driven blade 10 are gradually separated along with the rotation, and the clamped cut branches and leaves are placed at the designated positions.

6) And (5) repeating the steps 1) to 5) aiming at the next branch and leaf to be trimmed.

The above-described embodiments are merely preferred embodiments of the present invention, which should not be construed as limiting the invention. Various changes and modifications may be made by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present invention. Therefore, the technical scheme obtained by adopting the mode of equivalent replacement or equivalent transformation is within the protection scope of the invention.