A portable plant community species composition recognition device

Abstract

The present application relates to a kind of portable plant community species composition identification device, it is related to research tool technical field, including draw-bar box type box, box is equipped with collapsible support rod, the end of support rod is hingedly equipped with standard measurement frame, for enclosing the plant to be measured, the plant to be measured includes shrub, herbaceous plant and arbor plant, standard measurement frame is equipped with sliding cross bar, cross bar is equipped with mobile plant identification measurement component, plant identification measurement component is used to identify the kind of shrub or herbaceous plant being enclosed and measure the diameter of shrub and obtain the rhizome image of shrub or herbaceous plant;The top of box is equipped with third camera for identifying the kind of arbor plant and range finder for measuring the height of arbor plant.The identification device is convenient to carry and move, can identify the kind of different plants, can conveniently measure the diameter at breast height of arbor plant and height, and the diameter of shrub or the number of herbaceous plant.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of research tools, and particularly relates to a portable plant community species composition identification device. BACKGROUND

[0002] Plant community species composition identification refers to the process of identifying and recording various plant species existing in a plant community in a specific area.

[0003] The existing plant community species composition identification device, such as a high-precision laser radar scanner, can obtain three-dimensional structure information of plants, but such equipment is bulky and heavy, and usually needs to be carried by a vehicle or an unmanned aerial vehicle. The former is extremely inconvenient in complex terrain mountainous areas, remote forests and other wild environments. Due to the portability problem, researchers are difficult to cover all areas they want to study in a large area of field investigation. The latter has a high cost and is insufficient in energy supply in a wild environment. The existing identification device mainly focuses on plant species identification, such as an image recognition-based device, which can determine the plant species by photographing the leaves, flowers and other parts of the plant, and matching the plant features in the database with the image recognition algorithm. However, the device lacks the function of collecting important morphological and quantitative parameters such as the diameter at breast height, tree height, ground diameter of arbor plants or shrub plants, and the number and rhizome of herbaceous plants.

[0004] Therefore, the application provides a portable plant community species composition identification device to solve the above problems. SUMMARY

[0005] The application aims to provide a portable plant community species composition identification device to solve the problems in the background art.

[0006] The application achieves the above-mentioned purpose through the following technical solutions.

[0007] The portable plant community species composition identification device comprises a pull rod box type box body, a foldable support rod is arranged through the box body, and a standard measurement frame is hingedly arranged at the end of the support rod to frame the plant to be measured. The plant to be measured comprises shrub plants, herbaceous plants and arbor plants. A sliding cross bar is arranged on the standard measurement frame, and a movable plant identification and measurement assembly is arranged on the cross bar. The plant identification and measurement assembly is used to identify the species of the framed shrub plants or herbaceous plants, measure the ground diameter of the shrub plants, and obtain the rhizome image of the shrub plants or herbaceous plants. A third camera for identifying the species of the arbor plants and a range finder for measuring the tree height of the arbor plants are arranged on the top of the box body.

[0008] The standard measurement frame comprises two plate bodies and two telescopic rods between the two plate bodies, the end of the telescopic rod is clamped with the plate body, the inner side of the plate body and the telescopic rod is provided with a laser light belt for emitting a mark light, and the inner side of the plate body is further provided with a distance measuring sensor for measuring the diameter of the arbor plant.

[0009] As a further optimization scheme of the application, the bottom of the box body is provided with wheels, the top of the box body is provided with a mounting seat for mounting a third camera and a range finder, the back of the box body is provided with a pull rod, the front of the box body is provided with a touch screen, and the box body is further provided with a groove for placing the support rod and the standard measurement frame in a folded state.

[0010] As a further optimization scheme of the application, the support rod comprises a plurality of rod body units clamped at the head and tail, and a plurality of insertion holes are arranged at equal intervals on the rod body unit; a row of positioning holes are arranged at equal intervals on both sides of the front of the box body, and a positioning pin for fixing the support rod is arranged between the positioning hole and the insertion hole.

[0011] As a further optimization scheme of the application, the end of the outermost rod body unit is provided with a fixing block, and the side surface and the bottom surface of the fixing block are provided with clamping grooves for clamping the rod body unit; the end of the standard measurement frame is provided with a rotating shaft hinged with the fixing block, and the top of the fixing block is provided with a knob for locking the rotating shaft.

[0012] As a further optimization scheme of the application, the outer sides of both ends of the two plate bodies are hingedly provided with leg rods.

[0013] As a further optimization scheme of the application, the end of the cross rod is hingedly provided with a sliding block and a knob for locking both; one of the plate bodies is provided with a through groove, the sliding block is slidingly arranged in the through groove, and the sliding block is provided with a knob for locking.

[0014] As a further optimization scheme of the application, the plant identification and measurement assembly comprises a sliding sleeve slidingly arranged on the cross rod; the bottom of the sliding sleeve is provided with a first camera for identifying the species of shrub plants or herb plants, a mounting block is detachably fixed in the sliding sleeve, a measurement rod is movably arranged through the mounting block, the top end of the measurement rod is provided with a holding frame, the bottom end of the measurement rod is provided with a universal roller, a movable block is slidingly arranged on the lower part of the measurement rod, the movable block is provided with a clamping piece for measuring the ground diameter of the shrub plant and a second camera for shooting the rhizome condition of the shrub plant or herb plant; the top of the sliding sleeve is provided with a semicircular groove for placing the measurement rod.

[0015] As a further optimization scheme of the present application, a scale is arranged in the holding frame, a pull block is slidably arranged on the scale, a pull rope is arranged at the bottom of the pull block, and the pull rope is used to control the two clamping members to move towards each other.

[0016] As a further optimization scheme of the present application, the bottom of the box is further provided with a length measuring mechanism, which is used to measure the moving distance of the wheel to estimate the area of the collection area and the number of shrubs or herbaceous plants in the collection area.

[0017] As a further optimization scheme of the present application, the length measuring mechanism comprises a first fixed plate, a second fixed plate and a counter fixed on the bottom of the box; an active rod is arranged through the first fixed plate, a first metal sheet is fixed at one end of the active rod, a first wedge-shaped block is fixed at the other end of the active rod, a spring is sleeved on the active rod between the first wedge-shaped block and the first fixed plate, and a second metal sheet matched with the first metal sheet is fixed on the second fixed plate; the length measuring mechanism further comprises a second wedge-shaped block fixed on the wheel and rotating with the wheel, and the second wedge-shaped block is pressed with the first wedge-shaped block to connect the counter.

[0018] The present application has the following beneficial effects:

[0019] 1、The box, the wheel and the pull rod are arranged, so that the device is convenient to carry and move; the first camera, the clamping member, the second camera, the third camera, the range finder and the distance measuring sensor are arranged, so that the device can identify different types of plants, and can conveniently measure the diameter at breast height of arbor plants and the number of herbaceous plants.

[0020] 2、The support rod and the standard measurement frame are arranged, the support rod can adjust the standard measurement frame to be away from the box, and in the pulling process of the box, the data at the center of the collection area can be collected through the standard measurement frame; the arrangement of the standard measurement frame enables the collection personnel to accurately grasp the sample collection area, so that the plants in the sample collection area can be comprehensively collected.

[0021] 3、The length measuring mechanism is arranged, so that the device has the ability to estimate the number of shrubs or herbaceous plants in the entire collection area, so that the situation of the shrubs or herbaceous plants in the collection area can be accurately monitored and evaluated; the length of the collection area is obtained through the length measuring mechanism, the area of the collection area is estimated based on the length, and the number of shrubs or herbaceous plants in the entire collection area is estimated based on the number of shrubs or herbaceous plants in the standard measurement frame. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1Overall structure of the application Figure 1 ;

[0023] Figure 2 Overall structure of the application Figure 2 ;

[0024] Figure 3 Supporting rod structure of the application

[0025] Figure 4 Standard measurement frame structure of the application Figure 1 ;

[0026] Figure 2 Standard measurement frame structure of the application Figure 6 ;

[0027] Figure 7 Crossbar and plant recognition measurement assembly structure of the application

[0028] Figure 8 Measurement rod top end structure of the application

[0029] Figures 1-2 Length measurement mechanism structure of the application

[0030] In the figure:

[0031] 1, box; 101, wheel; 102, pull rod; 103, groove; 104, touch screen; 105, positioning hole; 106, mounting seat; 2, supporting rod; 201, rod body unit; 202, insertion hole; 203, fixed block; 204, clamping groove; 3, standard measurement frame; 301, plate body; 302, telescopic rod; 303, laser lamp strip; 304, distance measuring sensor; 305, through slot; 306, supporting leg rod; 4, crossbar; 401, sliding block; 5, plant recognition measurement assembly; 501, sliding sleeve; 502, first camera; 503, mounting block; 504, measurement rod; 505, holding frame; 506, universal roller; 507, movable block; 508, clamping piece; 509, second camera; 510, semicircular groove; 511, scale; 512, pull block; 513, pull rope; 6, length measurement mechanism; 601, first fixed plate; 602, second fixed plate; 603, counter; 604, movable rod; 605, first metal sheet; 606, first wedge-shaped block; 607, spring; 608, second metal sheet; 609, second wedge-shaped block. DETAILED DESCRIPTION

[0032] The application will be further described in detail below with reference to the drawings. It is necessary to point out here that the following specific embodiments are only used to further illustrate the application and cannot be understood as limiting the scope of protection of the application. Those skilled in the art can make some non-essential improvements and adjustments to the application according to the above application content.

[0033] Embodiment one

[0034] In order to solve the problem that the existing plant community species composition recognition device is not convenient to carry, and the function is single, and it is difficult to collect the diameter at breast height and tree height of arbor plants and the ground diameter of shrub plants, please refer to Figure 6 The application provides a portable plant community species composition recognition device, which comprises a pull rod box type box body 1, a foldable support rod 2 is arranged through the box body 1, a standard measurement frame 3 is hingedly arranged at the end of the support rod 2 and is used for boxing the plants to be measured, the plants to be measured comprise shrub plants, herbaceous plants and arbor plants, a sliding cross rod 4 is arranged on the standard measurement frame 3, a movable plant recognition and measurement assembly 5 is arranged on the cross rod 4, the plant recognition and measurement assembly 5 is used for identifying the species of the boxed shrub plants or herbaceous plants and measuring the ground diameter of the shrub plants and obtaining the rhizome image of the shrub plants or herbaceous plants, and a third camera for identifying the species of the arbor plants and a range finder for measuring the tree height of the arbor plants are arranged on the top of the box body 1.

[0035] The bottom of the pull rod box type box body 1 is provided with wheels 101, the top of the box body 1 is provided with a mounting seat 106 for mounting the third camera and the range finder, the back of the box body 1 is provided with a pull rod 102, the front of the box body 1 is provided with a touch screen 104, and the box body 1 is further provided with a groove 103 for placing the support rod 2 and the standard measurement frame 3 in the folded state. The wheels 101 and the pull rod 102 are arranged so that the device is convenient to carry and transport and is more convenient for collecting plant community information. When the height of the arbor plant needs to be collected, the horizontal distance between the box body 1 and the arbor plant and the distance from the box body 1 to the crown of the arbor plant are measured by the range finder, the height of the arbor plant is calculated based on the knowledge of trigonometric functions, and the image of the arbor plant is captured by the third camera for identification.

[0036] As Figure 6As shown, the end of the crossbar 4 is hingedly provided with a sliding block 401 and a knob for locking both; the frame of the standard measuring frame 3 is provided with a through slot 305, and the sliding block 401 is slidingly arranged in the through slot 305 and is provided with a knob for locking. The crossbar 4 can be moved along the plate body 301, thereby driving the plant identification and measurement assembly 5 to move, and meanwhile the plant identification and measurement assembly 5 can be moved along the crossbar 4, so that the plant identification and measurement assembly 5 can be adjusted to various positions in the standard measuring frame 3, thereby enabling comprehensive monitoring of the plants in the standard measuring frame 3; the crossbar 4 is hingedly matched with the sliding block 401, so that the crossbar 4 can be turned onto the plate body 301 when not in use, thereby facilitating folding and placing of the standard measuring frame 3.

[0037] As shown in the drawings, Figure 7 The plant identification and measurement assembly 5 comprises a sliding sleeve 501 slidingly arranged on the crossbar 4; the bottom of the sliding sleeve 501 is provided with a first camera 502 for identifying the species of shrubs or herbaceous plants, and a mounting block 503 is detachably fixed in the sliding sleeve 501, a measuring rod 504 is movably arranged on the mounting block 503, the top end of the measuring rod 504 is provided with a holding frame 505, the bottom end of the measuring rod 504 is provided with a universal roller 506, the lower part of the measuring rod 504 is slidingly provided with a movable block 507, the movable block 507 is provided with a clamping piece 508 for measuring the ground diameter of shrubs and a second camera 509 for shooting the root condition of shrubs or herbaceous plants; the top of the sliding sleeve 501 is provided with a semicircular groove 510 for placing the measuring rod 504.

[0038] In use, the first camera 502 is used to shoot photos of shrubs or herbaceous plants in the standard measuring frame 3 for identification and quantity statistics of various shrubs or herbaceous plants, the position of the movable block 507 on the measuring rod 504 is adjusted, such as to 20 cm from the ground, the roots of the shrubs are clamped by the two clamping pieces 508, and the distance between the two is the ground diameter data, and the second camera 509 is used to shoot photos of the root condition of the shrubs; the measuring rod 504 is driven to rotate by the holding frame 505, and multi-directional collection is performed to improve the accuracy of the ground diameter data measurement of the shrubs; after the measurement is completed, the mounting block 503 is detached from the sliding sleeve 501, and the measuring rod 504 is clamped into the semicircular groove 510, thereby facilitating folding of the standard measuring frame 3.

[0039] In order to further improve the convenience of measuring the ground diameter of shrubs, as shown in the drawings, Figures 3-4As shown, the holding frame 505 is provided with a scale 511, and a pull block 512 is slidably arranged on the scale 511. The bottom of the pull block 512 is provided with a pull rope 513 for controlling the two clamping pieces 508 to move towards each other. The clamping pieces 508 are slidably arranged in the movable block 507, and the movable block 507 is provided with a reset spring for resetting the clamping pieces 508. By pulling the pull block 512 upwards, the pull block 512 drives the two clamping pieces 508 to move towards each other until the two clamping pieces 508 clamp the shrub. The position of the pull block 512 is measured by the scale 511, and the diameter data of the shrub is obtained. The user can collect the data without bending over, and the data can be read conveniently.

[0040] Embodiment Two

[0041] On the basis of the first embodiment, in order to facilitate the collection of data at the center of the collection area and facilitate the folding and carrying of the whole device, the support rod 2 is provided. Figure 2 As shown, the support rod 2 includes a plurality of rod units 201 connected at the head and tail, and a plurality of insertion holes 202 are arranged at equal intervals on the rod units 201. The front sides of the box body 1 are each provided with a row of positioning holes 105 arranged at equal intervals, and the positioning holes 105 and the insertion holes 202 are provided with positioning pins for fixing the support rod 2. The end of the outermost rod unit 201 is provided with a fixed block 203, and the side surface and the bottom surface of the fixed block 203 are each provided with a clamping groove 204 for clamping the rod unit 201. The end of the standard measurement frame 3 is provided with a rotating shaft hinged to the fixed block 203, and the top of the fixed block 203 is provided with a knob for locking the rotating shaft. The support rod 2 can be adjusted to be away from the box body 1, and the data at the center of the collection area can be collected by the standard measurement frame 3 during the pulling of the box body 1. The length of the support rod 2 can be adjusted based on actual needs. The support rod 2 can also be adjusted to be vertical, so that the height of the standard measurement frame 3 is adjusted to an appropriate position, such as at least 1.3 meters from the ground, to facilitate the collection of the diameter data of the arbor plants. When adjusting, the top end of the rod unit 201 is clamped into the clamping groove 204 on the bottom surface of the fixed block 203, and the rod unit 201 is vertically fixed in the groove 103 by the positioning pin.

[0042] The standard measurement frame 3 includes two plate bodies 301 and two telescopic rods 302 between the two plate bodies 301. The ends of the telescopic rods 302 are clamped to the plate bodies 301. The inner sides of the plate bodies 301 and the telescopic rods 302 are each provided with a laser light belt 303 for emitting a marking light. The inner side of the plate body 301 is also provided with a distance measuring sensor 304 for measuring the diameter of the arbor plants.

[0043] The specification of the standard measurement frame 3 is set based on actual needs, for example, it can be a square frame with a size of 1 square meter. When in use, the standard measurement frame 3 is taken out of the groove 103 and connected with the support rod 2, then the length of the telescopic rod 302 is adjusted, the angle of the standard measurement frame 3 is adjusted based on the slope of the ground, and the marking light is emitted by the laser light belt 303 to enable the collector to accurately grasp the sample area. When it is necessary to measure the diameter at breast height of an arbor plant, one of the telescopic rods 302 is removed, at this time, the standard measurement frame 3 forms a gap for the arbor plant to pass through, and the distance of the arbor plant located in the standard measurement frame 3 is measured by the plurality of distance measuring sensors 304 to obtain the diameter at breast height of the arbor plant.

[0044] In order to improve the convenience of use of the standard measurement frame 3, the outer sides of both the plate bodies 301 are hingedly provided with leg rods 306. When the box 1 is inconvenient to move to the collection area, the standard measurement frame 3 can be detached from the support rod 2, then the standard measurement frame 3 is lifted to the best sampling point, the leg rods 306 are opened, and the standard measurement frame 3 is supported by the four leg rods 306 to facilitate information collection.

[0045] Embodiment Three

[0046] On the basis of the embodiment one and the embodiment two, in order to accurately monitor and evaluate the situation of the shrub plants or herbaceous plants in the collection area, the number change of the shrub plants or herbaceous plants is measured periodically, for example, the number of the shrub plants or herbaceous plants in the standard measurement frame 3 is counted, and the number of the shrub plants or herbaceous plants in the collection area is estimated based on the area of the collection area. Figure 8 ​ As shown in the figure, the bottom of the box 1 is further provided with a length measuring mechanism 6, which is used to measure the moving distance of the wheels 101 to estimate the area of the collection area and the number of the shrub plants or herbaceous plants in the collection area. The box 1 is pulled along the boundary of the collection area, the length of the collection area is obtained by the length measuring mechanism 6, the area of the collection area is estimated based on the length, and the number of the shrub plants or herbaceous plants in the entire collection area is estimated based on the number of the shrub plants or herbaceous plants in the standard measurement frame 3.

[0047] The length measuring mechanism 6 comprises a first fixed plate 601, a second fixed plate 602 and a counter 603 fixed on the bottom of the box 1. The first fixed plate 601 is provided with a movable rod 604 penetrating therethrough, one end of the movable rod 604 is fixedly provided with a first metal sheet 605, and the other end is fixedly provided with a first wedge block 606, a spring 607 is sleeved on the movable rod 604 between the first wedge block 606 and the first fixed plate 601, and the second fixed plate 602 is fixedly provided with a second metal sheet 608 matched with the first metal sheet 605. The length measuring mechanism 6 further comprises a second wedge block 609 fixed on the wheels 101 and rotating with the wheels 101, the second wedge block 609 is pressed with the first wedge block 606 to connect the counter 603.

[0048] ​In use, the wheel 101 drives the second wedge 609 to rotate, and when the second wedge 609 rotates to the first wedge 606, the first wedge 606 drives the movable rod 604 to move, at this time the spring 607 is compressed, the movable rod 604 drives the first metal sheet 605 to move to the second metal sheet 608, when the first metal sheet 605 contacts the second metal sheet 608, the circuit of the counter 603 is connected to realize counting, with the continuous rotation of the second wedge 609, when the second wedge 609 is separated from the first wedge 606, the first wedge 606 is reset under the action of the spring 607, the first metal sheet 605 is separated from the second metal sheet 608, the circuit of the counter 603 is disconnected, the number of the counter 603 is counted to obtain the rolling circle number of the wheel 101, and then the length of the moving path of the wheel 101 is obtained.

[0049] The above-described embodiments only express one embodiment of the present application, which is described in detail, but cannot be understood as the limitation of the patent scope of the present application. It should be pointed out that, for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which belong to the protection scope of the present application.

Claims

1. A portable plant community species composition recognition device comprising a suitcase type case (1), characterized in that: The box (1) is provided with a foldable support rod (2) penetrating through the box (1), the end of the support rod (2) is hingedly provided with a standard measuring frame (3) for enclosing the plant to be measured, the standard measuring frame (3) is provided with a sliding cross rod (4), the cross rod (4) is provided with a movable plant identification and measuring assembly (5), the plant identification and measuring assembly (5) is used for identifying the type of shrub or herb plant enclosed and measuring the ground diameter of the shrub and obtaining the rhizome image of the shrub or herb plant; The top of the box (1) is provided with a third camera for identifying the type of tree plant and a range finder for measuring the height of the tree plant; The standard measuring frame (3) comprises two plate bodies (301) and two telescopic rods (302) located between the two plate bodies (301), the ends of the telescopic rods (302) are clamped with the plate bodies (301), the inner sides of the plate bodies (301) and the telescopic rods (302) are provided with laser light strips (303) for emitting marking light, and the inner side of the plate body (301) is further provided with a range finding sensor (304) for measuring the breast height of the tree plant; The plant identification and measuring assembly (5) comprises a sliding sleeve (501) slidingly arranged on the cross rod (4), the bottom of the sliding sleeve (501) is provided with a first camera (502) for identifying the type of shrub or herb plant, a mounting block (503) is detachably fixed in the sliding sleeve (501), a measuring rod (504) is movably arranged on the mounting block (503), the top end of the measuring rod (504) is provided with a holding frame (505), the bottom end of the measuring rod (504) is provided with a universal roller (506), a movable block (507) is slidingly arranged on the lower part of the measuring rod (504), the movable block (507) is provided with a clamping piece (508) for measuring the ground diameter of the shrub and a second camera (509) for shooting the rhizome condition of the shrub or herb plant; The top of the sliding sleeve (501) is provided with a semicircular groove (510) for placing the measuring rod (504).

2. A portable plant community species composition recognition device according to claim 1, characterized in that: The box (1) is provided with wheels (101) at the bottom, a mounting seat (106) for mounting the third camera and the range finder is arranged on the top of the box (1), a pull rod (102) is arranged on the back of the box (1), a touch screen (104) is arranged on the front of the box (1), and a groove (103) for placing the support rod (2) and the standard measuring frame (3) in the folded state is further arranged on the box (1).

3. The portable plant community species composition recognition device according to claim 1, characterized in that: The support rod (2) comprises a plurality of rod body units (201) which are clamped at the head and tail, a plurality of insertion holes (202) are arranged at equal intervals on the rod body unit (201); The front of the box (1) is provided with a row of positioning holes (105) arranged at equal intervals on both sides, and a positioning pin for fixing the support rod (2) is arranged between the positioning hole (105) and the insertion hole (202).

4. A portable plant community species composition recognition device according to claim 3, characterised in that: The end of the outermost rod body unit (201) is provided with a fixing block (203), the side surface and the bottom surface of the fixing block (203) are provided with clamping grooves (204) for clamping the rod body unit (201); The end of the standard measuring frame (3) is provided with a rotating shaft hinged with the fixing block (203), and the top of the fixing block (203) is provided with a knob for locking the rotating shaft.

5. The portable plant community species composition recognition device of claim 1, wherein: Both ends of the outer side of the two plate bodies (301) are hingedly provided with leg rods (306).

6. The portable plant community species composition recognition device of claim 1, wherein: The end of the horizontal rod (4) is hingedly provided with a sliding block (401) and a knob for locking both; One of the plate bodies (301) is provided with a through groove (305), the sliding block (401) is slidingly arranged in the through groove (305), and the sliding block (401) is provided with a knob for locking.

7. The portable plant community species composition recognition device of claim 1, wherein: The holding frame (505) is provided with a scale (511), the scale (511) is slidingly provided with a pulling block (512), the bottom of the pulling block (512) is provided with a pulling rope (513), and the pulling rope (513) is used for controlling two clamping pieces (508) to approach each other; The clamping piece (508) is slidingly arranged in the movable block (507), and the movable block (507) is provided with a reset spring for resetting the clamping piece (508).

8. The portable plant community species composition recognition device of claim 1, wherein: The bottom of the box body (1) is further provided with a length measuring mechanism (6), and the length measuring mechanism (6) is used for measuring the moving distance of the wheel (101) to estimate the area of the collection area and the number of shrubs or herbaceous plants in the collection area.

9. A portable plant community species composition recognition device according to claim 8, characterised in that: The length measuring mechanism (6) comprises a first fixed plate (601), a second fixed plate (602) and a counter (603) fixed on the bottom of the box body (1); The first fixed plate (601) is provided with a movable rod (604) penetrating through, one end of the movable rod (604) is fixedly provided with a first metal sheet (605), the other end is fixedly provided with a first wedge-shaped block (606), the movable rod (604) between the first wedge-shaped block (606) and the first fixed plate (601) is sleeved with a spring (607), and the second fixed plate (602) is fixedly provided with a second metal sheet (608) matched with the first metal sheet (605); The length measuring mechanism (6) further comprises a second wedge-shaped block (609) fixed on the wheel (101) and rotating with the wheel (101), and the second wedge-shaped block (609) is pressed with the first wedge-shaped block (606) to connect the counter (603).

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