Portable plant community species composition identification device

Abstract

The invention relates to a portable plant community species composition identification device, and relates to the technical field of research tools, the portable plant community species composition identification device comprises a draw-bar box type box body, a foldable supporting rod is arranged on the box body in a penetrating mode, and a standard measurement frame is hinged to the end of the supporting rod and used for framing a plant to be measured; the plants to be measured comprise shrub plants, herbaceous plants and arbor plants, a sliding cross rod is arranged on the standard measurement frame, and a movable plant identification measurement assembly is arranged on the cross rod. The plant identification and measurement assembly is used for identifying types of framed shrub plants or herbaceous plants, measuring ground diameters of the shrub plants and obtaining rhizome images of the shrub plants or herbaceous plants; the top of the box body is provided with a third camera used for identifying the type of the arbor plant and a distance measuring instrument used for measuring the height of the arbor plant. The identification device is convenient to carry and move, can identify the types of different plants, and can conveniently measure the diameter at breast height and the height of an arbor plant and the ground diameter of a shrub plant or the number of herbaceous plants.

Description

Technical Field

[0001] The invention belongs to the technical field of research tools, and in particular is a portable device for identifying species composition of plant communities. Background Art

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

[0003] Existing plant community species composition identification devices, such as high-precision laser radar scanners, can obtain three-dimensional structural information of plants, but such devices are large and heavy, and usually need to be mounted on vehicles or drones. The former is extremely inconvenient in field environments such as mountainous areas with complex terrain and remote forests. Due to portability issues, it is difficult for researchers to cover all areas they want to study in large-scale field surveys. The latter is expensive and has insufficient energy supply in field environments. Existing identification devices mainly focus on plant species identification, such as image recognition-based devices, which can identify plant species by photographing plant leaves, flowers and other parts, and using image recognition algorithms to match plant features in the database. However, the collection function of important morphological and quantitative parameters such as the diameter at breast height, tree height, and ground diameter of trees or shrubs, and the rhizomes and number of herbaceous plants is missing.

[0004] To this end, we provide a portable plant community species composition identification device to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a portable device for identifying species composition of plant communities in response to the problems of the background technology.

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0007] A portable plant community species composition identification device comprises a trolley case, wherein a foldable support rod is provided through the case, and a standard measurement frame is hingedly provided at the end of the support rod for framing plants to be measured, wherein the plants to be measured include shrubs, herbaceous plants and tree plants, and a sliding cross bar is provided on the standard measurement frame, wherein a movable plant identification and measurement component is provided on the cross bar, and the plant identification and measurement component is used to identify the type of the framed shrub or herbaceous plant, measure the ground diameter of the shrub and obtain the root and stem image of the shrub or herbaceous plant; a third camera for identifying the type of the tree plant and a rangefinder for measuring the tree height of the tree plant are provided on the top of the case.

[0008] The standard measurement frame includes two plates and two telescopic rods located between the two plates, the ends of the telescopic rods are clamped with the plates, the inner sides of the plates and the telescopic rods are provided with laser light strips for emitting marking light, and the inner side of the plates is also provided with a ranging sensor for measuring the breast diameter of tree plants.

[0009] As a further optimization scheme of the present invention, the bottom of the trolley case is provided with wheels, the top of the case is provided with a mounting base for installing a third camera and a rangefinder, the back of the case is provided with a pull rod, the front of the case is provided with a touch screen, and the case is also provided with grooves for placing support rods and a standard measuring frame in a folded state.

[0010] As a further optimization scheme of the present invention, the support rod includes a plurality of rod body units connected end to end, and the rod body units are provided with a plurality of equally spaced sockets; a row of equally spaced positioning holes are provided on both sides of the front side of the box body, and a positioning pin for fixing the support rod is provided between the positioning holes and the sockets.

[0011] As a further optimization scheme of the present invention, a fixing block is provided at the end of the outermost rod unit, and a slot for clamping the rod unit is provided on the side and bottom surfaces of the fixing block; a rotating shaft hinged to the fixing block is provided at the end of the standard measuring frame, and a knob for locking the rotating shaft is provided on the top of the fixing block.

[0012] As a further optimization solution of the present invention, both ends of the outer sides of the two plate bodies are hingedly provided with outrigger rods.

[0013] As a further optimization scheme of the present invention, the end of the cross bar is hingedly provided with a slider and a knob for locking the two; one of the plate bodies is provided with a through groove, the slider is slidably arranged in the through groove and the slider is provided with a knob for locking.

[0014] As a further optimization scheme of the present invention, the plant identification and measurement component includes a sliding sleeve slidably arranged on a cross bar; a first camera for identifying the species of shrubs or herbaceous plants is provided at the bottom of the sliding sleeve, a mounting block is detachably fixed in the sliding sleeve, a measuring rod is movably penetrated through the mounting block, a holding frame is provided at the top of the measuring rod, a universal roller is provided at the bottom of the measuring rod, a movable block is provided on the lower sliding sleeve of the measuring rod, a clamp for measuring the ground diameter of shrubs and a second camera for photographing the root and stem conditions of shrubs or herbaceous plants is provided on the movable block; a semicircular groove for placing the measuring rod is provided on the top of the sliding sleeve.

[0015] As a further optimization scheme of the present invention, a scale is provided in the holding frame, a pull block is slidably provided on the scale, a pull rope is provided at the bottom of the pull block, and the pull rope is used to control the two clamping members to move closer to each other; the clamping member is slidably provided in the movable block, and a reset spring for resetting the clamping member is provided in the movable block.

[0016] As a further optimization solution of the present invention, a length measuring mechanism is also provided at the bottom of the box, and the length measuring mechanism 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 invention, the length measuring mechanism includes a first fixed plate, a second fixed plate and a counter fixed at the bottom of the box body; a movable rod is penetrated by the first fixed plate, a first metal sheet is fixed at one end of the movable rod, and a first wedge block is fixed at the other end, a spring is sleeved on the movable rod between the first wedge block and the first fixed plate, and a second metal sheet matching the first metal sheet is fixed on the second fixed plate; the length measuring mechanism also includes a second wedge block fixed on the wheel and rotating therewith, and the second wedge block is squeezed with the first wedge block to connect the counter.

[0018] The beneficial effects of the present invention are:

[0019] 1. The present invention provides a box, wheels and a pull rod so that the device is easy to carry and move. By providing a first camera, a clamp, a second camera, a third camera, a rangefinder and a rangefinder sensor, the device can identify different plant species and conveniently measure the breast diameter and tree height of arbor plants, as well as the ground diameter of shrubs or the number of herbaceous plants.

[0020] 2. The present invention sets a support rod and a standard measurement frame. The support rod can adjust the standard measurement frame to be away from the outside of the box. During the pulling process of the box, the standard measurement frame can collect data located at the center of the collection area. The setting of the standard measurement frame enables the collector to accurately grasp the sample collection area, thereby performing comprehensive data collection on the plants in the sample collection area.

[0021] 3. The present invention provides a length measuring mechanism so that the device has the ability to estimate the number of shrubs or herbaceous plants in the entire collection area, thereby accurately monitoring and evaluating the situation of the shrubs or herbaceous plants in the collection area. The side length of the collection area is obtained through the length measuring mechanism, and the area of ​​the collection area is estimated based on the side length. Then, based on the number of shrubs or herbaceous plants within the standard measurement frame, the number of shrubs or herbaceous plants in the entire collection area is estimated. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1The overall structure of the present invention is shown in three dimensions. Figure 1 ;

[0023] Figure 2 The overall structure of the present invention is shown in three dimensions. Figure 2 ;

[0024] Figure 3 It is a schematic diagram of the support rod structure of the present invention;

[0025] Figure 4 The standard measurement framework structure of the present invention is shown in FIG. Figure 1 ;

[0026] Figure 5 The standard measurement framework structure of the present invention is shown in FIG. Figure 2 ;

[0027] Figure 6 It is a schematic diagram of the structure of the crossbar and plant identification and measurement assembly of the present invention;

[0028] Figure 7 It is a schematic diagram of the top structure of the measuring rod of the present invention;

[0029] Figure 8 It is a schematic diagram of the length measuring mechanism structure of the present invention.

[0030] In the figure:

[0031] 1. Box; 101. Wheel; 102. Pull rod; 103. Groove; 104. Touch screen; 105. Positioning hole; 106. Mounting seat; 2. Support rod; 201. Rod unit; 202. Socket; 203. Fixing block; 204. Slot; 3. Standard measurement frame; 301. Plate; 302. Telescopic rod; 303. Laser light strip; 304. Distance sensor; 305. Through slot; 306. Leg rod; 4. Crossbar; 401. Sliding block; 5. Plant identification and measurement assembly; 501. Sliding sleeve; 502. First camera Head; 503, mounting block; 504, measuring 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 measuring mechanism; 601, first fixed plate; 602, second fixed plate; 603, counter; 604, movable rod; 605, first metal sheet; 606, first wedge block; 607, spring; 608, second metal sheet; 609, second wedge block. DETAILED DESCRIPTION

[0032] The present application is further described in detail below in conjunction with the accompanying drawings. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technical personnel in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0033] Embodiment 1

[0034] In order to solve the problem that the existing plant community species composition identification device is not convenient to carry, has a single function, and is difficult to collect the breast diameter and tree height of arbor plants and the ground diameter of shrubs, please refer to Figure 1-Figure 2 The present invention provides a portable plant community species composition identification device, including a trolley case 1, a foldable support rod 2 is passed through the case 1, and a standard measurement frame 3 is hinged at the end of the support rod 2 for framing plants to be measured. The plants to be measured include shrubs, herbaceous plants and tree plants. A sliding cross bar 4 is provided on the standard measurement frame 3, and a movable plant identification and measurement component 5 is provided on the cross bar 4. The plant identification and measurement component 5 is used to identify the type of the framed shrub or herbaceous plant, measure the ground diameter of the shrub plant, and obtain the root and stem image of the shrub or herbaceous plant; a third camera for identifying the type of the tree plant and a rangefinder for measuring the tree height of the tree plant are provided on the top of the case 1.

[0035] The bottom of the trolley case 1 is provided with wheels 101, the top of the case 1 is provided with a mounting seat 106 for mounting a third camera and a rangefinder, a pull rod 102 is provided on the back of the case 1, a touch screen 104 is provided on the front of the case 1, and a groove 103 for placing the support rod 2 and the standard measurement frame 3 in a folded state is also provided on the case 1. The arrangement of the wheels 101 and the pull rod 102 makes the device easy to carry and transport, and more convenient for collecting plant community information. When it is necessary to collect the height of arbor plants, the horizontal distance between the case 1 and the arbor plants and the distance from the arbor plant crown are measured by the rangefinder, and the height of the arbor plants is calculated based on the knowledge of trigonometric functions, and the image of the arbor plants is photographed by the third camera for identification.

[0036] like Figure 6As shown, the end of the crossbar 4 is hingedly provided with a slider 401 and a knob for locking the two; the frame of the standard measurement frame 3 is provided with a through slot 305, the slider 401 is slidably arranged in the through slot 305, and the slider 401 is provided with a knob for locking. The crossbar 4 can move along the plate 301, thereby driving the plant identification and measurement component 5 to move, and the plant identification and measurement component 5 can move along the crossbar 4, so that the plant identification and measurement component 5 can be adjusted to various positions in the standard measurement frame 3, so that the plants in the standard measurement frame 3 can be fully monitored; the crossbar 4 is hingedly matched with the slider 401, so that the crossbar 4 can be turned to the plate 301 when not in use, so as to facilitate the folding and placement of the standard measurement frame 3.

[0037] like Figure 6 As shown, the plant identification and measurement component 5 includes a sliding sleeve 501 slidably arranged on the cross bar 4; a first camera 502 for identifying the species of shrubs or herbaceous plants is provided at the bottom of the sliding sleeve 501, a mounting block 503 is detachably fixed in the sliding sleeve 501, a measuring rod 504 is movably penetrated on the mounting block 503, a gripping frame 505 is provided at the top of the measuring rod 504, a universal roller 506 is provided at the bottom of the measuring rod 504, a movable block 507 is provided on the lower sliding sleeve of the measuring rod 504, a clamping piece 508 for measuring the ground diameter of shrubs and a second camera 509 for photographing the rhizome status of shrubs or herbaceous plants are provided on the movable block 507; a semicircular groove 510 for placing the measuring rod 504 is provided on the top of the sliding sleeve 501.

[0038] When in use, the first camera 502 is used to take photos of shrubs or herbaceous plants located in the standard measuring frame 3 to identify and count the various shrubs or herbaceous plants, and the position of the movable block 507 on the measuring rod 504 is adjusted, such as adjusted to 20 cm from the ground. The rhizomes of the shrubs are clamped by two clamping members 508, and the distance between the two is the ground diameter data. The second camera 509 is used to take photos of the rhizomes of the shrubs; the measuring rod 504 is driven to rotate by the holding frame 505 to collect data in multiple directions to improve the accuracy of the measurement of the ground diameter data of the shrubs; after the measurement is completed, the mounting block 503 is removed from the sliding sleeve 501, and the measuring rod 504 is inserted into the semicircular groove 510 to facilitate the folding of the standard measuring frame 3.

[0039] In order to further improve the convenience of measuring the ground diameter of shrubs, Figure 7As shown, a scale 511 is provided in the gripping frame 505, a pull block 512 is slidably provided on the scale 511, a pull rope 513 is provided at the bottom of the pull block 512, and the pull rope 513 is used to control the two clamping members 508 to move closer to each other; the clamping member 508 is slidably provided in the movable block 507, and a reset spring for resetting the clamping member 508 is provided in the movable block 507. By pulling the pull block 512 upward, the pull block 512 drives the two clamping members 508 to move closer to each other until the two clamping members 508 clamp the shrub plant, and the position of the pull block 512 is measured by the scale 511, so as to obtain the ground diameter data of the shrub plant, so as to avoid the collector bending over to collect and facilitate the reading of data.

[0040] Embodiment 2

[0041] On the basis of the first embodiment, in order to facilitate the collection of data located at the center of the collection area and facilitate the folding and carrying of the entire device, as shown in FIG. Figure 3-Figure 4 As shown, the support rod 2 includes a plurality of rod units 201 connected end to end, and a plurality of equally spaced insertion holes 202 are provided on the rod unit 201; a row of equally spaced positioning holes 105 are provided on both sides of the front of the box body 1, and a positioning pin for fixing the support rod 2 is provided between the positioning holes 105 and the insertion holes 202; a fixing block 203 is provided at the end of the outermost rod unit 201, and a slot 204 for clamping the rod unit 201 is provided on the side and bottom of the fixing block 203; a rotating shaft hinged to the fixing block 203 is provided at the end of the standard measuring frame 3, and a knob for locking the rotating shaft is provided on the top of the fixing block 203. The setting of the support rod 2 enables the standard measurement frame 3 to be adjusted to be away from the box body 1. During the pulling process of the box body 1, data located at the center of the collection area can be collected through the standard measurement frame 3. The length of the support rod 2 is adjusted based on actual needs; the support rod 2 can also be adjusted to a vertical state, so that the height of the standard measurement frame 3 is adjusted to a suitable position, such as at least 1.3 meters from the ground, to facilitate the data collection of the diameter at breast height of the tree plant. During adjustment, the top of the rod unit 201 is inserted into the slot 204 on the bottom surface of the fixing 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 plates 301 and two telescopic rods 302 located between the two plates 301. The ends of the telescopic rods 302 are snap-connected to the plates 301. The inner sides of the plates 301 and the telescopic rods 302 are provided with laser light strips 303 for emitting marking light. The inner side of the plate 301 is also provided with a ranging sensor 304 for measuring the breast diameter of tree plants.

[0043] The specifications of the standard measurement frame 3 are set based on actual needs, such as being set to a square frame of 1 square meter. When in use, the standard measurement frame 3 is taken out of the groove 103 and connected to the support rod 2, and then the length of the telescopic rod 302 is adjusted. Based on the slope of the ground, the angle of the standard measurement frame 3 is adjusted, and a marking light is emitted by the laser light strip 303 to enable the collector to accurately grasp the sample area; when it is necessary to measure the breast diameter of the tree plant, one of the telescopic rods 302 is removed. At this time, a gap is formed in the standard measurement frame 3 for the tree plant to pass through. The distance of the tree plant in the standard measurement frame 3 is measured by multiple ranging sensors 304 to obtain the breast diameter of the tree plant.

[0044] In order to improve the convenience of using the standard measurement frame 3, both ends of the outer sides of the two plates 301 are hinged with outrigger rods 306. When the box 1 is not convenient to move to the collection area, the standard measurement frame 3 can be disassembled from the support rod 2, and then the standard measurement frame 3 can be lifted to the best sampling point, and the outrigger rods 306 can be opened. The standard measurement frame 3 is supported by four outrigger rods 306 to facilitate information collection.

[0045] Embodiment 3

[0046] On the basis of the first and second embodiments, in order to accurately monitor and evaluate the situation of shrubs or herbaceous plants in the collection area, the number changes of shrubs or herbaceous plants are measured regularly, such as Figure 2 , Figure 8 As shown, a length measuring mechanism 6 is also provided at the bottom of the box 1, and the length measuring mechanism 6 is used to measure the moving distance of the wheel 101 to estimate the area of ​​the collection area and the number of shrubs or herbs in the collection area. The box 1 is pulled to move along the boundary of the collection area, and the side length of the collection area is obtained by the length measuring mechanism 6. The area of ​​the collection area is estimated based on the side length, and then the number of shrubs or herbs in the standard measurement frame 3 is estimated.

[0047] The length measuring mechanism 6 includes a first fixed plate 601, a second fixed plate 602 and a counter 603 fixed at the bottom of the box body 1; a movable rod 604 is penetrated through the first fixed plate 601, a first metal sheet 605 is fixed at one end of the movable rod 604, and a first wedge block 606 is fixed at the other end; a spring 607 is sleeved on the movable rod 604 between the first wedge block 606 and the first fixed plate 601, and a second metal sheet 608 matching the first metal sheet 605 is fixed on the second fixed plate 602; the length measuring mechanism 6 also includes a second wedge block 609 fixed on the wheel 101 and rotating therewith, and the second wedge block 609 is squeezed with the first wedge block 606 to connect the counter 603.

[0048] When in use, the wheel 101 drives the second wedge block 609 to rotate. When the second wedge block 609 rotates to the first wedge block 606, it is squeezed, and the first wedge block 606 drives the movable rod 604 to move. At this time, the spring 607 is compressed, and the movable rod 604 drives the first metal sheet 605 to move toward 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 count. As the second wedge block 609 continues to rotate, when it separates from the first wedge block 606, under the action of the spring 607, the first wedge block 606 is reset, the first metal sheet 605 separates from the second metal sheet 608, and the circuit of the counter 603 is disconnected. By counting the number of counters 603, the number of rolling circles of the wheel 101 is obtained, thereby obtaining the length of the moving path of the wheel 101.

[0049] The above-mentioned embodiment only expresses one implementation mode of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A portable plant community species composition identification device, comprising a trolley case (1), characterized in that: The box body (1) is provided with a foldable support rod (2) extending through it, and a standard measurement frame (3) is hingedly provided at the end of the support rod (2) for framing the plants to be measured, wherein the plants to be measured include shrubs, herbaceous plants and tree plants, and the standard measurement frame (3) is provided with a sliding cross bar (4), and a movable plant identification and measurement component (5) is provided on the cross bar (4), and the plant identification and measurement component (5) is used to identify the type of the framed shrub or herbaceous plant, measure the ground diameter of the shrub, and obtain the rhizome image of the shrub or herbaceous plant; The top of the box (1) is provided with a third camera for identifying the type of the tree plant and a rangefinder for measuring the height of the tree plant; The standard measurement 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) being snap-connected with the plate bodies (301), the inner sides of the plate bodies (301) and the telescopic rods (302) are both provided with laser light strips (303) for emitting marking light, and the inner side of the plate bodies (301) is also provided with a distance measuring sensor (304) for measuring the diameter at breast height of an arbor plant.

2. A portable plant community species composition identification device according to claim 1, characterized in that: The bottom of the trolley case (1) is provided with wheels (101); the top of the case (1) is provided with a mounting seat (106) for mounting a third camera and a rangefinder; the back of the case (1) is provided with a pull rod (102); the front of the case (1) is provided with a touch screen (104); and the case (1) is also provided with a groove (103) for placing a support rod (2) in a folded state and a standard measurement frame (3).

3. A portable plant community species composition identification device according to claim 1, characterized in that: The support rod (2) comprises a plurality of rod units (201) connected end to end, and the rod unit (201) is provided with a plurality of equidistantly distributed insertion holes (202); Both sides of the front side of the box body (1) are provided with a row of positioning holes (105) distributed at equal intervals, and a positioning pin for fixing the support rod (2) is provided between the positioning holes (105) and the insertion hole (202).

4. A portable plant community species composition identification device according to claim 3, characterized in that: A fixing block (203) is provided at the end of the outermost rod unit (201), and a clamping groove (204) for clamping the rod unit (201) is provided on the side surface and the bottom surface of the fixing block (203); 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.

5. A portable plant community species composition identification device according to claim 1, characterized in that: Leg rods (306) are hingedly provided at both ends of the outer sides of the two plate bodies (301).

6. A portable plant community species composition identification device according to claim 1, characterized in that: The end of the crossbar (4) is hingedly provided with a slider (401) and a knob for locking the two; A through slot (305) is provided on one of the plates (301), the slider (401) is slidably disposed in the through slot (305), and a knob for locking is provided on the slider (401).

7. A portable plant community species composition identification device according to claim 1, characterized in that: The plant identification and measurement component (5) comprises a sliding sleeve (501) slidably arranged on the crossbar (4); A first camera (502) for identifying the type of shrubs or herbaceous plants is provided at the bottom of the sliding sleeve (501); a mounting block (503) is detachably fixed in the sliding sleeve (501); a measuring rod (504) is movably provided on the mounting block (503); a gripping frame (505) is provided at the top of the measuring rod (504); a universal roller (506) is provided at the bottom of the measuring rod (504); a movable block (507) is provided at the lower sliding sleeve of the measuring rod (504); a clamping piece (508) for measuring the ground diameter of shrubs and a second camera (509) for photographing the rhizome status of shrubs or herbaceous plants is provided on the movable block (507); The top of the sliding sleeve (501) is provided with a semicircular groove (510) for placing the measuring rod (504).

8. A portable plant community species composition identification device according to claim 7, characterized in that: A scale (511) is provided in the holding frame (505), a pull block (512) is slidably provided on the scale (511), a pull rope (513) is provided at the bottom of the pull block (512), and the pull rope (513) is used to control the two clamping members (508) to move closer to each other; The clamping member (508) is slidably disposed in the movable block (507), and a return spring for returning the clamping member (508) is disposed in the movable block (507).

9. A portable plant community species composition identification device according to claim 1, characterized in that: The bottom of the box (1) is also provided with a length measuring mechanism (6), and the length measuring mechanism (6) is used to measure 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.

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

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