CN118633424A - Intelligent lettuce leaf removing harvester - Google Patents

Abstract

The invention discloses an intelligent lettuce defoliation harvester, belonging to the technical field of agricultural mechanical equipment, and the technical scheme comprises the following steps: the vehicle frame is characterized in that a traveling wheel assembly is arranged at the bottom of the vehicle frame; the harvesting and conveying device is arranged at the front end of the frame in the traveling direction and is used for cutting and conveying lettuce; the defoliation treatment device is arranged at the upper end of the frame and is connected with the conveying end of the harvesting and conveying device, and is used for defoliation treatment of lettuce; the defoliation treatment device comprises a defoliation conveyor belt arranged above the harvesting conveyor device and a lifting conveyor belt arranged below the defoliation conveyor belt; the invention provides an intelligent lettuce defoliation harvester, which is characterized in that a travelling wheel assembly controls the movement of a frame, so that a harvesting and conveying device and a defoliation treatment device are mutually matched, defoliation conveying and other operations after cutting of lettuce are realized, the intelligent and automatic level of agricultural production is improved, the cost is saved, and the production efficiency is further improved.

Description

Intelligent lettuce leaf removing harvester

Technical Field

The invention belongs to the technical field of agricultural machinery and equipment, and particularly relates to an intelligent lettuce defoliating harvester.

Background Art

At present, lettuce is a widely grown and consumed vegetable, and it plays an important role worldwide. With the continuous advancement of agricultural modernization and the improvement of agricultural mechanization, the scale of lettuce cultivation has gradually expanded, and the demand for lettuce harvesters has also increased. The traditional manual harvesting method is inefficient, labor-intensive, and the leaf removal process is cumbersome, which cannot meet the needs of modern agriculture. The development of lettuce harvesters was born out of necessity and has become an important tool for improving production efficiency and saving labor costs.

In recent years, the cultivation and transplanting of lettuce in China have been mechanized, but the research on mechanized harvesting technology for lettuce and other vegetables is still being carried out and improved. Although the existing equipment has solved a lot of problems in the mechanization of lettuce harvesting in China, it still relies on other agricultural machinery and its lettuce defoliation function has not been improved and is not yet fully intelligent. Therefore, the machine that needs to be studied urgently is to realize the full intelligence of lettuce harvesting.

my country's agricultural mechanization and intelligent construction has received much attention, covering the following aspects:

1. Automation and intelligence: Some companies such as Zoomlion Heavy Industry Science & Technology Co., Ltd. and YTO (Luoyang) Agricultural Equipment Co., Ltd. focus on the development of automatic navigation, intelligent identification and adaptive control technologies to improve harvesting efficiency and reduce labor costs.

2. Multi-function and integration: Jiangsu Century Sunshine Group, Shenyang Agricultural Machinery Research Institute and other companies are committed to the research and development of S multi-function vegetable harvesters that can adapt to different crops and terrains, achieve multi-purpose use of one machine, and improve equipment utilization.

3. Precision agriculture technology: Beijing Agricultural Intelligent Equipment Technology Research Institute, Zhejiang University and others have started to use the Internet of Things, big data and artificial intelligence technologies to achieve accurate monitoring of the vegetable growth environment and precise grasp of the harvesting time.

4. Energy conservation and emission reduction: Golden Sun Agricultural Machinery Group, Foton Lovol and other companies are committed to developing energy-saving vegetable harvesters to reduce energy consumption and emissions in response to the national energy conservation and emission reduction policy.

5. Human-computer interaction: Zhejiang Yuhuan CNC Machinery Co., Ltd. and other companies are committed to improving the operating interface, enhancing user experience, making operations easier, and reducing the operator's labor intensity.

Through the investigation, it was found that various domestic vegetable harvesters have big and small problems in technological innovation, product homogeneity, adaptability, cost and environmental protection, and market promotion. Domestic vegetable harvesters often rely on imports for core technologies and key components, and their independent innovation capabilities need to be improved. Most vegetable harvesters on the market have similar functions and technologies, lacking differentiated competition. Some vegetable harvesters are not adaptable to different terrains, especially in rainy and mountainous areas, where their use is limited and affects the user experience of farmers. In addition, the after-sales service network in some areas is not sound, and the supply of accessories is not timely, which affects the user experience. High-performance vegetable harvesters are expensive and not easily accepted by small-scale farmers. The emission levels of some vegetable harvesters fail to meet the latest national environmental protection standards, and they cause great harm to the environment during production and use. The lack of market promotion efforts for some new technologies and new products has led to low awareness of new vegetable harvesters among farmers.

China's vegetable harvester companies have made some progress in technological innovation, product diversification, and intelligent level, but they still face challenges such as insufficient technological innovation capabilities, fierce market competition, and product adaptability and environmental performance that need to be improved. In the future, companies need to increase R&D investment, improve independent innovation capabilities, and strengthen market promotion and service network construction to better meet market demand and national policy guidance. Based on the above advantages and disadvantages, the lettuce harvester project was designed and developed.

Summary of the invention

The purpose of the present invention is to provide an intelligent lettuce defoliating harvester, which controls the movement of the frame through a walking wheel assembly, so that the harvesting and conveying device and the defoliating processing device cooperate with each other, and realize operations such as defoliating and conveying the lettuce after cutting, thereby improving the intelligence and automation level of agricultural production, saving costs, and further improving production efficiency.

The object of the present invention is achieved by providing an intelligent lettuce leaf removing harvester, comprising:

A frame, wherein a running wheel assembly is provided at the bottom of the frame;

A harvesting and conveying device is arranged at the front end of the frame in the direction of travel and is used for cutting and conveying lettuce;

A leaf removal device is arranged at the upper end of the frame and connected to the conveying end of the harvesting and conveying device, and is used for leaf removal of lettuce; and

The defoliation processing device includes a defoliation conveyor belt arranged above the harvesting conveyor device and a lifting conveyor belt arranged below the defoliation conveyor belt. The defoliation conveyor belt cooperates with the defoliation plate in the lifting conveyor belt to lift, squeeze and remove leaves of the lettuce.

Furthermore, the travel wheel assembly includes four independently driven travel wheels arranged at the bottom of the frame, forming a differential drive for the travel and steering of the frame.

Furthermore, the harvesting and conveying device includes a cutting tool fixedly arranged at the bottom of the frame and a clamping conveyor belt arranged above the cutting tool, and the clamping conveyor belt is inclined upward or horizontally arranged along the conveying direction; the cutting tool includes two disc blade groups, and the disc-shaped blades in the two disc blade groups are arranged horizontally adjacent to each other; the front end of the clamping conveyor belt is placed in the upper front of the two disc blade groups.

Furthermore, the clamping conveyor belt includes two parallel arranged conveyor belt units, the conveyor belt unit includes a vertically arranged conveyor belt and a power source for driving the conveyor belt, a plurality of flexible clamping strips are arranged in the width direction of the outer surface of the conveyor belt, and the plurality of flexible clamping strips are evenly distributed in the length direction of the conveyor belt; the two power sources rotate synchronously in opposite directions to clamp the conveyor belt for transporting it to the inside of the frame.

Furthermore, the leaf removing conveyor belt includes two removal conveyor crawler units and the leaf removing plate arranged in parallel along the conveying direction, the removal conveyor crawler unit includes a crawler motor vertically fixed on the frame and a removal conveyor crawler rotatably connected to the crawler motor, the outer surface of the removal conveyor crawler is provided with a plurality of clamping heads, and the plurality of clamping heads are evenly distributed in the length direction of the removal conveyor crawler; the two crawler motors rotate synchronously in opposite directions, and are used to transport the leaf removing conveyor belt to the outside of the frame.

Furthermore, the lifting conveyor belt includes a supporting conveyor belt and a driving roller group, the driving roller group is tiltedly arranged on the frame, and the driving roller group is driven by a conveying motor fixedly arranged on the frame; a plurality of transverse rods are arranged on the outer surface of the supporting conveyor belt, the transverse rods are arranged in the width direction of the supporting conveyor belt, and a plurality of the transverse rods are evenly distributed in the length direction of the supporting conveyor belt.

Furthermore, a storage container is provided on the frame, and the storage container is arranged directly below the output end of the lifting conveyor belt.

Furthermore, the end of the rejection conveyor belt is coaxially connected to the end adjacent to the driving conveyor belt, and the conveying speeds of the clamping conveyor belt, the leaf removal conveyor belt and the lifting conveyor belt are consistent.

Furthermore, the clamping conveyor belt is tilted, and its inclination angle is 20°.

Furthermore, the storage container is detachably arranged on the vehicle frame, and an electrically connected pressure sensor and buzzer are arranged in the storage container.

The beneficial effects of the present invention are embodied in:

1. In the present invention, a traveling wheel assembly is provided to control the movement of the frame, so that the harvesting and conveying device on the frame can cut and convey the lettuce, and convey the cut lettuce to the defoliating device for defoliation. Furthermore, the cut lettuce is lifted and conveyed in cooperation with the lifting conveyor belt and the defoliating conveyor belt, and during the lifting process, the lettuce is squeezed upward under the guidance of the defoliating conveyor belt, and the old leaves on the side walls of the lettuce fall off under the action of the corresponding blocking members, so that the old leaves of the lettuce are removed. The whole device has an integrated and automated function for the operation of the lettuce, which greatly improves the convenience of harvesting the lettuce.

2. In the present invention, by arranging four independently driven running wheels in the running wheel assembly, differential drive between the wheels can be realized, and a steering effect can be achieved by utilizing sliding friction. The present invention is suitable for outdoor mountainous terrain, making up for the disadvantage that lettuce harvesting is restricted by terrain, eliminating the physical structure of a mechanical differential, and only needs to design a set of electronic differential controllers for front wheel steering based on Ackerman steering. By coordinating and controlling the rotation speeds of the four hub motors respectively, the rotation speeds of each wheel meet the requirements when turning, thereby achieving the purpose of steering and greatly improving the efficiency of harvesting lettuce.

3. In the present invention, the cutting tool and the clamping conveyor belt above the cutting tool are arranged to cooperate to complete the cutting of the lettuce and convey it to the defoliating device to wait for defoliation. When the lettuce is placed in the machine, the disc blade will cut it. During this process, the lettuce moves forward and the disc blade cuts the back of the lettuce. In the actual lettuce harvesting process, the disc cutting blade should cut the lettuce at a vertical or nearly vertical angle to the lettuce itself. This cutting method can ensure that the lettuce is evenly cut into the required flat cross-section, which is convenient for subsequent conveying, defoliating and storage.

4. In the present invention, by setting two parallel conveyor belt units, the lettuce can be effectively output in a clamping manner. In actual operation, the clamping conveyor belt is arranged to be tilted upward, and the two power sources rotate synchronously in opposite directions, which can effectively convey the lettuce to a high place. The design of the conveyor belt can better wrap and support the lettuce, avoiding the problem of unstable clamping and tipping due to the vertical center of gravity height of the lettuce; further, a plurality of flexible clamping strips are arranged in the width direction of the outer surface of the conveyor belt to enhance the stability of the clamping of the lettuce.

5. In the present invention, by setting the cooperation between two rejection conveyor crawler units and two defoliating plates, and making the spacing between the defoliating plates smaller than the spacing between the two rejection conveyor crawler units, the two defoliating plates can remove old leaves from the lettuce that is clamped, guided and ascended under the two rejection conveyor crawler units. The multiple clamping heads arranged on the outer surface of the rejection conveyor crawler enhance the clamping and stabilizing effect of the lettuce. The two rejection conveyor crawler units can clamp the lettuce to prevent it from falling over, and can also clamp the top of the lettuce to allow it to move upward stably.

6. In the present invention, a lifting conveyor belt is provided to realize the lifting conveyance of the lettuce conveyed by the clamping conveyor belt, so that the lettuce can be vertically guided and clamped in the two upper rejection conveyor crawler units, and pass through the two leaf removal plates to remove the old leaves; further, a plurality of transverse bars are provided on the outer surface of the supporting conveyor belt, and a clamping groove is formed between the two transverse bars, which is beneficial to clamp the lettuce and prevent it from falling down under the action of gravity. Because the lettuce is too long and the center of gravity is too high, the two rejection conveyor crawler units guide and clamp the upper end of the lettuce, and then apply a supporting force at the top to prevent it from falling, thereby facilitating the stable removal of the old leaves.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

Fig. 1 is a schematic diagram of the structure of a harvester from a side view of the present invention;

FIG2 is a schematic diagram of the structure of a harvester from a top view according to the present invention;

FIG3 is a schematic diagram of the front view structure of the harvester of the present invention;

FIG4 is a simplified working view of the travel wheel assembly of the present invention;

FIG5 is a schematic diagram of speed analysis of a traveling wheel assembly according to the present invention;

FIG6 is a finite element analysis diagram of a disc-shaped blade of the present invention;

FIG. 7 is a force analysis diagram of lettuce transmission according to the present invention.

In the accompanying drawings, 1-frame, 2-walking wheel assembly, 3-harvesting conveyor device, 4-leaf removal processing device, 5-leaf removal conveyor belt, 6-lifting conveyor belt, 7-leaf removal plate, 8-walking wheel, 9-cutting tool, 10-clamping conveyor belt, 11-disc blade group, 12-disc blade, 13-conveyor belt, 15-flexible clamping strip, 16-removing conveyor crawler unit, 17-leaf removal plate, 18-removing conveyor crawler, 19-clamping head, 20-crawler motor, 21-support conveyor belt, 22-driving roller shaft group, 23-conveyor motor, 24-transverse rod, 25-storage container, 26-conveyor belt unit, 27-universal joint coupling.

DETAILED DESCRIPTION

The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

As shown in Figures 1 to 7, an intelligent lettuce leaf removing harvester includes:

A vehicle frame 1, wherein a running wheel assembly 2 is provided at the bottom of the vehicle frame 1;

A harvesting and conveying device 3, arranged at the front end of the frame 1 in the traveling direction, is used for cutting and conveying lettuce;

A leaf removal device 4 is arranged at the upper end of the frame 1 and connected to the conveying end of the harvesting and conveying device 3, and is used for leaf removal of lettuce; and

The defoliation processing device 4 includes a defoliation conveyor belt 5 arranged above the harvesting conveyor device 3 and a lifting conveyor belt 6 arranged below the defoliation conveyor belt 5. The defoliation conveyor belt 5 cooperates with the defoliation plate 7 in the lifting conveyor belt 6 to lift, squeeze and remove leaves of the lettuce.

The function of the intelligent defoliating lettuce harvester is to defoliate and harvest lettuce through the mutual cooperation between mechanical structures, which greatly improves the user's harvesting efficiency, reduces a large amount of labor resources, and makes the harvesting of lettuce more mechanized and intelligent.

The movement of the frame 1 is controlled by arranging the traveling wheel assembly 2, so that the harvesting and conveying device 3 on the frame 1 can cut and convey the lettuce, and convey the cut lettuce to the defoliating device 4 for defoliation operation; further, the cut lettuce is lifted and conveyed with the cooperation of the lifting conveyor belt 6 and the defoliating conveyor belt 5, and during the lifting process, the lettuce is squeezed upward under the guidance of the defoliating conveyor belt 5, and the old leaves on the side walls of the lettuce fall off under the action of the corresponding obstruction members, so that the old leaves of the lettuce are removed. The whole equipment has the function of integration and automation for the operation of lettuce, which greatly improves the convenience of harvesting lettuce.

As a preferred embodiment of the present invention, the harvester is composed of four parts, namely, a frame 1, a harvesting and conveying device 3, a leaf removal device 4, and a collection basket. A high-strength bottom plate and frame 1 are used to carry the harvesting part and resist the destructive factors caused by various terrains. The entire body adopts a frame structure, which not only realizes the lightweight of the product but also ensures the mechanical performance requirements required during operation. In terms of lettuce harvesting, a disc blade and a conveyor belt 13 are combined to realize the harvesting and transmission of lettuce.

In the process of defoliating lettuce, two pairs of defoliating conveyor belts 5 and defoliating plates 7 of the defoliating processing device 4 are used to defoliate the lettuce and convey it to the rear collection frame, thereby completing the harvesting of the lettuce. In order to ensure the reliability of the transmission and to be able to harvest the lettuce normally in a harsh environment, a four-wheel drive is used to ensure sufficient driving force. In order to ensure the stability of the vehicle body during operation, tires with large diameters and rough surfaces are used.

Preferably, the travel wheel assembly 2 includes four independently driven travel wheels 8 arranged at the bottom of the frame 1 to form a differential drive for the travel and steering of the frame 1.

By arranging four independently driven running wheels in the running wheel assembly, differential drive between the wheels can be realized, and sliding friction is used to achieve a steering effect. The method is suitable for outdoor mountainous terrain, which makes up for the disadvantage that lettuce harvesting is restricted by terrain, eliminates the physical structure of a mechanical differential, and only needs to design a set of electronic differential controllers for front wheel steering based on Ackerman steering. By coordinating and controlling the speeds of the four hub motors respectively, the speeds of each wheel meet the requirements of turning, thereby achieving the purpose of steering and greatly improving the efficiency of harvesting lettuce.

Analysis of the longitudinal velocity of the left wheel:

As shown in Figure 5, the speed of the two left wheels contacting the ground can be expressed as

Among them, _v1 and _v2 represent the linear speed of points A and B respectively, and _r1 and _r2 correspond to their turning radii respectively.

In RTΔA-Q-ICR and RTΔB-Q-ICR, the trigonometric transformation is used to transform formula (1), which is expressed as

Where _α1 and _α2 represent the angles of A-ICR, B-ICR and Q-ICR respectively.

After further simplifying formula (2), it can be expressed as

v _1χ ＝v ₁ cosα ₁ ＝v ₂ cosα ₂ ＝v _2χ #(3)

In the formula, ν _1χ and v _2χ represent the component velocities of v ₁ and v ₂ respectively.

Based on the above analysis, it can be seen that the longitudinal component velocities of points A and B are the same. Similarly, it can be analyzed that the longitudinal component velocities of points C and D are the same, but the longitudinal component velocities of the left and right wheels are different.

Analysis of the lateral velocity of the front wheels: Using the same idea as the longitudinal velocity analysis method of the wheels on both sides, as shown in Figure 5, the speed of the two front wheels at the contact point with the ground can be expressed as

Among them, v ₄ represents the linear velocity of point D, and r ₄ corresponds to its turning radius.

In RTΔA-Q-ICR and RTΔD-P-ICR, the trigonometric transformation is used to transform formula (4), which is expressed as

Wherein, _α1 and _α4 represent the angles of A-ICR, D-ICR and P-ICR respectively.

Because AQ and DP have the same length, we can further simplify formula (5) to express it as v _1y =v ₁ sinα ₁ #(6)

In the formula, v _1y and v _4y represent the component velocities of v ₁ and v ₄ respectively.

Based on the above analysis, it can be seen that the lateral component velocities of points A and D are the same. Similarly, it can be analyzed that the lateral component velocities of points B and C are the same, but the lateral component velocities of the front and rear wheels are different.

Advantages of differential drive: There are several reasons for using a four-wheel differential to drive a harvester: (1) This technology involves the front and rear wheels of the harvester in the steering process, thereby improving the handling stability of the harvester during high-speed steering and the maneuverability during low-speed turning. (2) Compared with traditional steering systems, the mechanical structure of differential steering is relatively simple. Since it does not require components such as steering gears, steering rods, and steering gear boxes, it can reduce the overall weight and complexity of the vehicle, and reduce manufacturing and maintenance costs. (3) Differential steering can achieve precise steering control by fine-tuning the speed difference between the left and right wheels, making the vehicle more flexible, stable, and easy to control during operation. This is especially important for vehicles that require delicate operations, such as construction machinery and agricultural tractors. (4) Differential steering can make it easier for vehicles to pass obstacles in complex terrain because it can fine-tune the vehicle's trajectory by controlling the speed difference between the left and right wheels, thereby improving the vehicle's passability and off-road capabilities. (5) Compared with traditional steering systems, differential steering can reduce the damage to the ground when the vehicle is turning, because it can achieve steering by controlling the speed difference between the left and right wheels without generating large lateral friction on the ground, thereby reducing ground wear. (6) Differential steering is applicable to various types of vehicles, including tracked vehicles, wheeled vehicles, agricultural tractors, construction machinery, etc., and therefore has strong versatility and adaptability.

Calculation of the forces on the differential drive: When the harvester chassis is driving on the road, it has to overcome various resistances, so it is necessary to determine the dynamics of the chassis. Based on the fact that the motor output power is equal to the sum of the resistances on the moving chassis, the motion relationship is listed and the driving equation of the vehicle is established:

∑F＝F _f +F _w +F _i +F _j #(7)

Where: ∑F is the sum of driving resistance, including rolling resistance ∑F, air resistance ∑F, slope resistance _Fi and acceleration resistance _Fj .

1. Rolling resistance

When the mobile chassis is traveling on the ground, the contact between the tire and the ground will generate normal and tangential interaction forces, as well as deformation of the tire when rolling on the road surface. The rolling resistance formula is simplified to:

F _f =Wf#(8)

Where: W is the wheel load; f is the rolling resistance coefficient

2. Air resistance

When a vehicle is traveling in a straight line, the component of the air force in the direction of travel is called air resistance. Air resistance is mainly composed of pressure resistance and friction resistance. The air resistance formula is:

Where: _CD is the air resistance coefficient; A is the frontal area ( ^m2 ); u is the speed of the car (m/s)

3. Slope resistance

When the mobile chassis climbs a slope, the component of the chassis' gravity along the slope direction is the slope resistance. The formula is:

F _i =Gsinα#(10)

Where: G is the gravity acting on the mobile chassis (N); α is the ramp angle.

4. Acceleration resistance

When the mobile chassis is moving, there is an inertial force that keeps the vehicle moving at a constant speed. When the vehicle is accelerating, this inertial force must be overcome, which is the acceleration resistance. The formula for the acceleration resistance is:

Where: δ is the vehicle rotation mass conversion coefficient; m is the vehicle mass (kg); Driving acceleration.

Since the harvester works at a low speed, the air resistance is approximately considered to be zero, that is, _Fw = 0. The chassis energy consumption is related to the rolling resistance, maximum slope and acceleration during driving. Secondly, the chassis weight of the harvester is designed to be 35kg, and the rolling resistance coefficient is f = 0.25 according to the data.

First, the traction required by the maximum speedometer motor is provided. When the chassis is traveling at the maximum design speed on a horizontal road, the slope resistance _Fi and acceleration resistance _Fj are both 0, so

Ft _{= Ff} = f × G#(12)

Substituting the parameters into the formula, we get F _t = 87.5N

Preferably, the harvesting conveyor device 3 includes a cutting tool 9 fixedly arranged at the bottom of the frame 1 and a clamping conveyor belt 10 arranged above the cutting tool 9, and the clamping conveyor belt 10 is inclined upward or horizontally arranged along the conveying direction; the cutting tool 9 includes two disc blade groups 11, and the disc-shaped blades 12 in the two disc blade groups 11 are arranged horizontally adjacent to each other; the front end of the clamping conveyor belt 10 is placed in front of the upper part of the two disc blade groups 11.

As a preferred mode of the present embodiment, a disc-shaped blade 12 is added to the front bottom of the machine, and the motor is directly driven to rotate. Such a cutting device is bilaterally symmetrical, and is used to better cut off the lettuce root stem portion close to the ground. The cutting blade needs to meet the basic characteristics such as hardness, elasticity, wear resistance and corrosion resistance, and also needs to meet the requirements of mechanical structure parameters, so as to achieve cutting effects such as small cutting resistance, neat cutting, and smooth section. When the lettuce is placed in the machine, the disc blade will cut it off. In this process, the lettuce moves forward, and the disc blade cuts at the back of the lettuce at the same time. In the actual lettuce harvesting process, the disc cutting blade should be cut at an angle vertical to the lettuce itself or close to vertical. This cutting method can ensure that the lettuce is evenly cut into required flat sections.

The finite element stress analysis of the cutting tool is shown in Figure 6. Under the force of 30N, the tool made of tool steel will not produce stress deformation on the blade edge and the upper surface of the knife. This proves the rationality of the design of the cutting disc blade. When doing stress analysis on it, the yield force is 26Mp, and the maximum stress concentration point is 22Mp, which is less than the maximum yield force. The tool structure design is very reasonable. It can easily cut lettuce without causing the horizontal cutting tool to break.

Before the front harvesting knife harvests the lettuce, the trolley moves forward and enters the interlayer of the inclined pair of clamping conveyor belts 10. The pair of clamping conveyor belts 10 is driven by a motor-driven bearing to drive the conveyor belt 13 to move. The left conveyor belt 13 rotates counterclockwise, and the right conveyor belt 13 rotates clockwise, thereby ensuring that the lettuce can be smoothly moved to the rear end processing and leaf removal mechanism after being clamped by the conveyor belt 13.

Since the motor drives the bearing and then puts on the conveyor belt for transportation, the motor specification used here is a 12V/110 rpm JGB37-520 encoder motor. At the same time, because the motor directly drives the bearing to drive the conveyor belt, the transmission ratio is 1:1 and the transmission efficiency η is also 1.

V＝wrη#(13)

V: Linear speed of conveyor belt (unit: m/s)

w: angular velocity of the motor (unit: radians/second)

r: Radius of the conveyor belt (unit: meter)

η: is the transmission efficiency (taking into account the energy loss in the transmission, usually a decimal between 0 and 1)

The diameter of the conveyor belt is D = 35 mm = 0.035 m, so the radius

The motor speed w = 110rpm, because so

The transmission efficiency is η=1.

From the above formula, it can be concluded that the maximum linear speed of the conveyor belt is V = 0.20 m/s. At this speed, not only the effective transmission rate can be guaranteed, but also no secondary damage can be caused to the lettuce harvest, thereby avoiding the impact of harvest losses on the freshness and taste of the lettuce.

Preferably, the clamping conveyor belt 10 includes two parallel arranged conveyor belt units 26, the conveyor belt unit 26 includes a vertically arranged conveyor belt 13 and a power source for driving the conveyor belt 13, a plurality of flexible clamping strips 15 are arranged in the width direction of the outer surface of the conveyor belt 13, and the plurality of flexible clamping strips 15 are evenly distributed in the length direction of the conveyor belt 13; the two power sources rotate synchronously in opposite directions to clamp the conveyor belt 10 for transporting it to the inside of the frame 1.

As a preferred mode of this embodiment, the conveyor belts 10 clamped on both sides rotate synchronously in opposite directions, which can effectively convey the lettuce to a high place. The design of the conveyor belt 13 can better wrap and support the lettuce, avoiding the situation where the lettuce cannot be clamped and falls due to the problem of the vertical center of gravity height.

According to the design requirements, a maximum of six mature lettuces can be clamped on the conveyor belt at a time to further ensure that the lettuce will not fall over during the oblique upward conveying process. The angle of the clamped conveyor belt should also be considered as appropriate. The conveying force and gravity acting on the lettuce are shown in Figure 7, where G is the gravity exerted on the lettuce, P is the conveying force of the conveyor belt on the lettuce, and F is the supporting force of the conveying mechanism on the oblique upper side of the lettuce. The force analysis is shown in the figure as the inclination angle θ of the conveyor belt. According to the force analysis, G=Psinx, P=Fcosθ. During the conveying process, the inclination angle θ of the conveyor belt affects both the conveying force P and the supporting force F, and affects the conveying of the lettuce.

In the actual harvesting and production process, we fully considered that in order to further enhance the friction of the lettuce in the conveyor belt, the conveyor belt material is PVC (polyvinyl chloride) which is not easy to fall off, and 3D printing technology is used to manufacture multiple flexible clamping strips. The lettuce will be supported by the conveyor belt and moved up stably.

Preferably, the leaf removal conveyor belt 5 includes two removal conveyor crawler units 16 and the leaf removal plate 7 which are arranged in parallel along the conveying direction; the removal conveyor crawler unit 16 includes a crawler motor 20 vertically fixed on the frame 1 and a removal conveyor crawler 18 rotatably connected to the crawler motor 20; a plurality of clamping heads 19 are arranged on the outer surface of the removal conveyor crawler 18, and the plurality of clamping heads 19 are evenly distributed in the length direction of the removal conveyor crawler 18; the two crawler motors 1 rotate synchronously in opposite directions, so as to transport the leaf removal conveyor belt 5 to the outside of the frame 1.

By setting the cooperation between the two rejection conveyor crawler units 16 and the two defoliating plates 7, and making the spacing between the defoliating plates 7 smaller than the spacing between the two rejection conveyor crawler units 16, the two defoliating plates 7 can remove the old leaves of the lettuce that is clamped, guided and ascended under the two rejection conveyor crawler units 16. The multiple clamping heads 19 arranged on the outer surface of the rejection conveyor crawler 18 enhance the clamping and stabilizing effect of the lettuce. The setting of the two rejection conveyor crawler units 16 can clamp the lettuce to prevent it from tipping over, and can also clamp the top of the lettuce to allow it to move upward stably.

During the lettuce harvesting process, in order to retain the stems of the main edible parts and remove the old leaves, a processing mechanism of the harvester is designed as shown in Figure 1. The processing mechanism adopts a bilaterally symmetrical structure, including a defoliation plate on the top that can be used to remove leaves. The defoliation plate is set to an acrylic plate. The lettuce is guided to the defoliation processing device through the front conveyor belt. The outer surface of the supporting conveyor belt 21 in the lifting conveyor belt 6 below the defoliation processing device is provided with a plurality of transverse rods 24, which can clamp the lettuce to prevent it from falling. At the same time, the clamping conveyor belt 10 can also clamp the top of the lettuce to allow it to move up stably. Afterwards, the old leaves are removed by the obstruction of the acrylic plate, thereby realizing the overall process of removing the old leaves from the lettuce. After the processing is completed, the processed lettuce is directly transmitted to the next link to ensure an efficient and continuous operation process.

Preferably, the lifting conveyor belt 6 includes a supporting conveyor belt 21 and a driving roller group 22, the driving roller group 22 is obliquely arranged on the frame 1, and the driving roller group 22 is driven by a conveying motor 23 fixedly arranged on the frame 1; the outer surface of the supporting conveyor belt 21 is provided with a plurality of transverse rods 24, the transverse rods 24 are arranged in the width direction of the supporting conveyor belt 21, and the plurality of transverse rods 24 are evenly distributed in the length direction of the supporting conveyor belt 21.

As shown in Figure 7, it is a force analysis diagram of lettuce at the leaf removal device. G is the gravity of lettuce, FN is the supporting force of the supporting conveyor belt, and P is the conveying force of the conveyor belt: the transverse rod on the surface of the supporting conveyor belt is used to clamp the lettuce to prevent it from falling down under the action of gravity; the acrylic plate is used to remove the old leaves of lettuce. The lettuce is slowly moved upward by the two upper and lower conveyor belts, the clamping conveyor belt 10 and the lifting conveyor belt 6, so that the acrylic plate can remove the old leaves of lettuce through friction; the upper conveyor belt 13, i.e. the clamping conveyor belt 10, is used to support the lettuce. Because the lettuce is too long, the center of gravity is too high, so it is necessary to apply a supporting force at the top to prevent it from falling.

Preferably, a storage container 25 is provided on the frame 1 , and the storage container 25 is arranged just below the output end of the lifting conveyor belt 6 .

Preferably, the conveying speeds of the clamping conveyor belt 10, the leaf removing conveyor belt 5 and the lifting conveyor belt 6 are consistent. The conveying speeds of the three ends are kept almost similar so that the lettuce can be stably moved on the conveyor belt.

The conveyor belts of the clamping conveyor belt 10 and the leaf removing conveyor belt 5 are connected by a universal joint coupling 27, and through precise angle calculation and on-site physical debugging, one motor can drive two conveyor belts, so the transmission speeds at these two places are consistent.

The linear speed of the lower conveyor belt is consistent with the above calculation formula.

V＝wrη#(13)

V: Linear speed of conveyor belt (unit: m/s)

w: angular velocity of the motor (unit: radians/second)

r: Radius of the conveyor belt (unit: meter)

η: is the transmission efficiency (taking into account the energy loss in the transmission, usually a decimal between 0 and 1)

The diameter of the conveyor belt is D = 60 mm = 0.060 m, so the radius is D = 60 mm = 0.060 m

The motor speed w = 110rpm, because so

The transmission efficiency is η=1.

The maximum linear speed of the conveyor belt is calculated to be V = 0.35m/s. Since the maximum speed of the cutting conveyor belt is only V = 0.20m/s, and it is connected to the upper conveyor belt with a universal coupling, the speed is consistent. However, we need to keep the conveying speeds of the three ends almost similar, so that the lettuce can move stably on the conveyor belt.

Preferably, the clamping conveyor belt 10 is tilted, and the inclination angle is 20°.

If the inclination angle θ is too large, the lettuce is prone to tipping and sliding during transportation. If the inclination angle θ is too small, the transportation length will be longer, which is not convenient for harvesting operations, and it is also impossible to reserve a certain height for the processing device at the back end. According to the overall design requirements, the inclination angle θ of the overall conveyor belt under rated conditions is determined to be 20°.

Preferably, the storage container 25 is detachably arranged on the vehicle frame 1, and an electrically connected pressure sensor and a buzzer are arranged in the storage container 25. When the weight of the lettuce contained in the storage container 25 reaches a predetermined amount, the buzzer sounds an alarm.

Working principle and working process of the present invention:

The intelligent lettuce defoliating harvester provided by the present invention controls the movement of the frame 1 by setting the walking wheel assembly 2 when working, so that the harvesting and conveying device 3 on the frame 1 can cut and convey the lettuce, and convey the cut lettuce to the defoliating processing device 4 for defoliation operation. Furthermore, the cut lettuce is lifted and conveyed in cooperation with the lifting conveyor belt 6 and the defoliating conveyor belt 5, and the lettuce is squeezed upward under the guidance of the defoliating conveyor belt 5 during the lifting process, and the old leaves on the side wall of the lettuce fall off under the action of the corresponding obstruction members, so that the old leaves of the lettuce are removed. The whole equipment has the function of integration and automation for the operation of lettuce, which greatly improves the convenience of harvesting lettuce.

Furthermore, by providing a lifting conveyor belt 6, the lettuce transported by the clamping conveyor belt 10 can be lifted and transported, so that the lettuce can be vertically guided and clamped in the two upper rejection conveyor crawler units 16, and pass between the two leaf removal plates 7 to remove the old leaves. Furthermore, a plurality of transverse rods 24 are provided on the outer surface of the supporting conveyor belt 21, and a groove is formed between the two transverse rods 24, which is beneficial to the clamping of the lettuce and prevents it from falling down under the action of gravity. Because the lettuce is too long and the center of gravity is too high, the two rejection conveyor crawler units 16 guide the upper end of the lettuce and apply a supporting force at the top to prevent it from falling, thereby facilitating the stable removal of the old leaves.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims (10)

1. An intelligent lettuce defoliation harvester, comprising:

The vehicle frame is characterized in that a traveling wheel assembly is arranged at the bottom of the vehicle frame;

The harvesting and conveying device is arranged at the front end of the frame in the traveling direction and is used for cutting and conveying lettuce;

The defoliation treatment device is arranged at the upper end of the frame and is connected with the conveying end of the harvesting and conveying device, and is used for defoliation treatment of lettuce; and

The defoliation treatment device comprises a defoliation conveying belt arranged above the harvesting conveying device and a lifting conveying belt arranged below the defoliation conveying belt, wherein the defoliation conveying belt is matched with conveying of defoliation plates in the lifting conveying belt and used for lifting, extruding and defoliating lettuce.

2. The intelligent lettuce defoliation harvester according to claim 1, wherein said travelling wheel assembly comprises 4 independently driven travelling wheels arranged at the bottom of the frame, forming a differential drive for travelling and steering of the frame.

3. The intelligent lettuce defoliation harvester according to claim 1, wherein said harvesting and conveying device comprises a cutting tool fixedly arranged at the bottom of the frame and a clamping conveyor belt arranged above the cutting tool, said clamping conveyor belt being arranged obliquely or horizontally upwards in the conveying direction; the cutting tool comprises two disc blade groups, and disc blades in the two disc blade groups are horizontally and adjacently matched; the front end of the clamping conveying belt is arranged at the upper front part of the two disc blade groups.

4. The intelligent lettuce defoliation harvester according to claim 3, wherein the clamping conveyor belt comprises two conveyor belt units which are arranged in parallel, wherein each conveyor belt unit comprises a vertically arranged conveyor belt and a power source for driving the conveyor belt, a plurality of flexible clamping strips are arranged on the outer surface of the conveyor belt in the width direction, and the flexible clamping strips are uniformly distributed in the length direction of the conveyor belt; the two power sources reversely and synchronously rotate and are used for clamping the conveying belt and conveying the conveying belt to the inside of the frame.

5. The intelligent lettuce defoliation harvester as claimed in claim 3, wherein the defoliation conveyor belt comprises two rejection conveyor track units and a defoliation plate, which are arranged in parallel along the conveying direction, the rejection conveyor track units comprise a track motor and a rejection conveyor track, wherein the track motor is vertically and fixedly arranged on a frame, the rejection conveyor track is rotationally connected with the track motor, a plurality of clamping heads are arranged on the outer surface of the rejection conveyor track, and the plurality of clamping heads are uniformly distributed along the length direction of the rejection conveyor track; the two crawler motors reversely and synchronously rotate and are used for conveying the defoliation conveyor belt to the outside of the frame.

6. The intelligent lettuce defoliation harvester according to claim 1, wherein said lifting conveyor comprises a supporting conveyor and a drive roller set, said drive roller set being arranged obliquely to the frame, said drive roller set being driven by a conveyor motor fixedly arranged to the frame; the outer surface of supporting conveyer belt is provided with a plurality of transverse rods, transverse rods set up in the width direction of supporting conveyer belt, and a plurality of transverse rods equipartition set up in the length direction of supporting conveyer belt.

7. The intelligent lettuce defoliation harvester as in claim 1, wherein a storage container is provided on the frame, the storage container being positioned directly below the output end of the lifting conveyor.

8. The intelligent lettuce defoliation harvester as in claim 3, wherein the ends of said culling conveyor tracks are coaxially connected to the ends of said drive conveyor belt, and wherein the conveying speeds of said clamping conveyor belt, said defoliation conveyor belt and said lifting conveyor belt are the same.

9. The intelligent lettuce defoliation harvester as in claim 3, wherein said clamping conveyor is inclined at an inclination of 20 °.

10. The intelligent lettuce defoliation harvester according to claim 7, wherein said container is detachably arranged on the frame, and wherein a pressure sensor and a buzzer are electrically connected to each other.