Carton clamp, fork truck control method and controller

Abstract

The application discloses a carton clamp, a forklift control method and a controller. The carton clamp comprises a rear hanging assembly, a clamp arm driving assembly and a pair of clamp arms. The clamp arm driving assembly comprises a hydraulic cylinder and an oil pressure detection module. The hydraulic cylinder is used for driving the clamp arm to clamp a carton. The oil pressure detection module is used for detecting the clamping force of the hydraulic cylinder. An acceleration detection module is arranged on the clamp arm. The acceleration detection module is used for detecting the acceleration of the carton when the carton slides in the clamp arm. The oil pressure detection module and the acceleration detection module send the detection values to the controller. The controller calculates the dynamic friction coefficient between the carton and the clamp arm, controls the clamp arm driving assembly to output the clamping force suitable for the carton, calculates the dynamic friction coefficient according to the acceleration value and the clamping force, and determines the required minimum clamping force. The clamping force output by the clamp arm is corrected, and the clamping force is prevented from being too large or too small.

Description

Technical Field

[0001] This invention relates to the field of forklift attachment technology, specifically to a carton clamp, a forklift control method, and a controller. Background Technology

[0002] Cardboard boxes are common outer packaging materials that protect products and facilitate storage and transportation during product distribution. Compared to wooden crates, woven bags, and plastic boxes, cardboard boxes are characterized by easy availability of materials, light weight, small size, ease of printing and manufacturing, and low cost.

[0003] However, it also has its drawbacks. Its relatively smooth outer surface and low hardness make it difficult to control the clamping force when using carton clamps to hold cartons. If the clamping force is too small, the clamping part may not be secure enough and the cartons may fall off during transfer. If the clamping force is too large, the carton may be over-clamped and easily damaged.

[0004] In the prior art, the importance of clamping force for cartons has already been noted. For example, application number 201710344110.3, entitled "Experimental Device for Carton Clamping Simulated by Hydraulic Forklift Handling", is used to test cartons before handling to determine the clamping force value and stacking height. Another example is that the weight of the cartons is obtained in advance through RFID tags, and then the forklift applies the corresponding clamping force.

[0005] The former requires conducting experiments on each type of outer packaging carton to determine the clamping force. However, in many cases, the outer packaging carton arrives along with the goods and there is no opportunity to conduct experiments beforehand. This method is time-consuming and labor-intensive. The latter only focuses on the weight of the goods and does not pay attention to the coefficient of dynamic friction between the carton and the clamping arm. In fact, different cartons have different surface roughness and cannot be generalized. For example, some cartons are coated with varnish or film, and the way the cable ties are tied may vary, all of which affect the friction between the carton and the clamping arm to varying degrees. Summary of the Invention

[0006] The purpose of this invention is to provide a carton clip.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The carton clamp includes a rear mounting assembly, a clamping arm drive assembly, and a pair of clamping arms, wherein:

[0009] The clamping arm drive assembly includes a hydraulic cylinder and an oil pressure detection module. The hydraulic cylinder is used to drive the clamping arm to clamp the carton, and the oil pressure detection module is used to detect the current clamping force of the hydraulic cylinder.

[0010] The clamping arm is equipped with an acceleration detection module, which is used to detect the acceleration of the carton as it slides down the clamping arm;

[0011] The hydraulic pressure detection module and the acceleration detection module send their detection values ​​to the controller, which calculates the dynamic friction coefficient between the carton and the clamping arm to control the clamping arm drive assembly to output a clamping force adapted to the carton.

[0012] Preferably, the clamping arm has a window for installing the acceleration detection module. The acceleration detection module includes a telescopic base, a friction wheel, and an encoder. The telescopic base is elastically arranged perpendicular to the clamping arm. The friction wheel is mounted on the telescopic base and has a portion extending out of the inner side of the clamping arm under the action of the telescopic base. The encoder is coaxially arranged with the friction wheel to obtain the acceleration of the friction wheel.

[0013] Preferably, the encoder is a shaft-mounted encoder, the friction wheels are a pair and are respectively disposed on both sides of the encoder, and the diameter of the encoder is smaller than the diameter of the friction wheels.

[0014] Preferably, the telescopic seat is a linear slide, and a spring is provided between the slide rod and the slide to achieve elastic setting.

[0015] Preferably, the telescopic seat is provided with an electromagnet in its base. When the electromagnet attracts the slide, the slide retracts against the spring force, causing the friction wheel to retract into the window.

[0016] Preferably, the electromagnet is a de-energized electromagnet.

[0017] Preferably, the clamping arm drive assembly further includes a guide rail, which includes a primary guide rail, a guide rail seat, and a secondary guide rail. Guide grooves are formed on both sides of the cross-section of the guide rail seat to slidably connect the primary guide rail and the secondary guide rail, respectively. The hydraulic cylinder includes a primary hydraulic cylinder and a secondary hydraulic cylinder. One end of the primary hydraulic cylinder is connected to the primary guide rail, and the other end is connected to one end of the guide rail seat. One end of the secondary hydraulic cylinder is connected to the other end of the guide rail seat, and the other end is connected to the secondary guide rail.

[0018] Another object of the present invention is to provide a forklift control method based on the aforementioned carton clamp, comprising:

[0019] S1. Obtain the weight of the carton;

[0020] S2. Predict the coefficient of dynamic friction between the carton and the clamping arm;

[0021] S3. Calculate the clamping force based on the weight of the carton and the coefficient of dynamic friction, and output the clamping force to hold the carton.

[0022] S4. Obtain controller load data and determine whether the load data is greater than or equal to the carton weight. If not, proceed to S5; if yes, proceed to S6.

[0023] S5. Increase the clamping force by the preset increment, then return to S4;

[0024] S6. Determine whether the encoder has received an acceleration signal. If not, proceed to S7; if yes, proceed to S8.

[0025] S7. Reduce the clamping force according to the preset amount, then return to S6;

[0026] S8. The controller calculates the coefficient of dynamic friction based on the weight and acceleration of the carton, and corrects the clamping force based on the coefficient of dynamic friction.

[0027] Preferably, it also includes: S9, stacking risk warning;

[0028] S91. Determine the aspect ratio of the carton. Check if the aspect ratio exceeds the threshold. If yes, proceed to S92; otherwise, the process terminates.

[0029] S92. Obtain the dynamic friction coefficient. Refer to the coefficient comparison table based on the dynamic friction coefficient to obtain the inter-carton dynamic friction coefficient corresponding to this dynamic friction coefficient in history.

[0030] S93. Calculate the sliding friction when the two cartons are stacked, and determine whether the sliding friction is less than the preset value. If so, output a risk warning of tipping over.

[0031] Another object of the present invention is to provide a forklift controller, including a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program, it implements the forklift control method as described above.

[0032] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0033] 1. This invention can detect the sliding acceleration of the carton under sliding conditions through an acceleration detection module and the clamping force of the hydraulic cylinder under sliding conditions through an oil pressure detection module. Then, the dynamic friction coefficient can be calculated based on the acceleration value and the clamping force to determine the minimum required clamping force and correct the clamping force output by the clamping arm to avoid excessive or insufficient clamping force.

[0034] 2. This invention provides a retractable friction wheel in the clamping arm, which abuts against the surface of the carton and rotates as the carton slides down, thus avoiding damage to the carton. At the same time, the angular acceleration of the friction wheel is obtained by an encoder, and then the acceleration value of the linear velocity is determined to determine the coefficient of kinetic friction.

[0035] 3. The telescopic seat of the present invention is equipped with an electromagnet in its base. When the electromagnet attracts the slide, the slide overcomes the elastic force of the spring and retracts, causing the friction wheel to retract into the window, thus avoiding damage to the acceleration detection module during daily clamping operations.

[0036] 4. This invention is equipped with multi-level guide rails, which can achieve the function of compressing goods with a large gap according to the volume of the carton.

[0037] 5. Based on the extension of the forklift control method of the present invention, the present invention can determine the stacking risk of cartons, output prompts, and prevent the stacking phenomenon caused by insufficient friction. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of the present invention;

[0039] Figure 2 This is a schematic diagram of the composition of the clamping arm drive assembly of the present invention;

[0040] Figure 3 This is a schematic diagram of the acceleration detection module of the present invention;

[0041] Figure 4 This is a schematic diagram of the acceleration detection module of the present invention (extended state);

[0042] Figure 5 This is a schematic diagram of the acceleration detection module of the present invention (extended state);

[0043] Figure 6 This is a schematic diagram of the acceleration detection module of the present invention (in retracted state);

[0044] Figure 7 This is a schematic diagram of the multi-stage guide rail of the present invention;

[0045] Figure 8 This is a flowchart illustrating the implementation logic of the method of the present invention;

[0046] Figure 9 This is a logical flowchart illustrating the risk warning of the present invention.

[0047] Explanation of reference numerals in the attached figures:

[0048] Rear-mounted component 100;

[0049] The clamping arm drive assembly 200, hydraulic cylinder 210, primary hydraulic cylinder 211, secondary hydraulic cylinder 212, oil pressure detection module 220, guide rail 230, primary guide rail 231, guide rail seat 232, guide groove 2321, and secondary guide rail 233 are included.

[0050] Clamping arm 300, friction plate 310, window 320;

[0051] Acceleration detection module 400, telescopic seat 410, spring 411, friction wheel 420, encoder 430, electromagnet 440, magnetic chuck 450. Detailed Implementation

[0052] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0053] Example 1

[0054] Please refer to Figure 1 As shown, this invention discloses a carton clamp, including a rear mounting assembly 100, a clamping arm drive assembly 200, and a pair of clamping arms 300. The rear mounting assembly 100 is used to mount the carton onto a forklift, and the clamping arm drive assembly 200 drives the pair of clamping arms 300 to open and clamp, achieving unloading or clamping. Friction plates 310 are provided on the clamping arms 300 to enhance the coefficient of friction, facilitating the clamping of the carton.

[0055] Please refer to Figure 2 As shown in the figure, in this application, the clamping arm drive assembly 200 includes a hydraulic cylinder 210 and an oil pressure detection module 220. The hydraulic cylinder 210 acts as an actuator to directly drive the clamping arm 300 to clamp the carton. The oil pressure detection module 220 is a pressure sensor that is installed in the oil supply circuit of the hydraulic cylinder 210 to detect the current clamping force of the hydraulic cylinder 210.

[0056] Please refer to Figure 3 As shown, an acceleration detection module 400 is provided in a clamping arm 300. The acceleration detection module 400 is used to detect the acceleration of the carton when it slides down in the clamping arm 300.

[0057] Thus, the forklift controller can obtain the current clamping force from the hydraulic pressure detection module 220 and the acceleration of the carton during sliding from the acceleration detection module 400. Based on the force balance condition, the friction calculation formula, and the acceleration calculation formula, it can determine the coefficient of dynamic friction between the carton and the clamping arm 300, thereby determining the minimum clamping force required to clamp the carton, and controlling the clamping arm drive assembly 200 to output a clamping force adapted to the carton. The calculation mechanism is described in detail in Embodiment 2 of this application.

[0058] Please refer to Figure 3 As shown, the clamping arm 300 has a window 320 for mounting the acceleration detection module 400. Please refer to... Figure 4 and Figure 5As shown, the acceleration detection module 400 includes a telescopic base 410, a friction wheel 420, and an encoder 430. The telescopic base 410 is elastically positioned perpendicular to the clamping arm 300. The friction wheel 420 is mounted on the telescopic base 410 and, under the action of the telescopic base 410, has a portion extending beyond the inner side of the clamping arm 300. That is, under the elastic action of the telescopic base 410, it can always effectively abut against the surface of the carton to convert the sliding signal value of the carton into a rolling signal value of the friction wheel 420. The encoder 430 is coaxially keyed to the friction wheel 420 to achieve synchronous rotation with the friction wheel 420, thereby obtaining the angular acceleration of the friction wheel 420 and determining its linear velocity based on the diameter of the friction wheel 420.

[0059] Please refer to Figure 4 and Figure 5 As shown, in a preferred embodiment, the encoder 430 is a through-shaft encoder 430, and the friction wheels 420 are a pair, with the diameter of the encoder 430 being smaller than the diameter of the friction wheels 420. In this way, the friction wheels 420 can be positioned on both sides of the encoder 430, thereby protecting the encoder 430 and preventing the carton surface from directly impacting and damaging it.

[0060] Please refer to Figure 4 and Figure 5 As shown, in this application, the telescopic seat 410 is a linear slide, and a spring 411 is provided between its slide rod and the slide to achieve elastic setting. To further reduce the size in the direction of the clamping arm 300, in this application, the spring 411 is a pagoda spring.

[0061] In addition, to avoid contact between the carton and the friction wheel 420 during normal operation, which could cause wear and tear on the friction wheel 420 or encoder 430, please refer to... Figure 4 and Figure 5 As shown, in a preferred embodiment, an electromagnet 440 is provided in the seat of the telescopic base 410. Thus, when the electromagnet 440 attracts the slide, the slide retracts against the spring force of the spring 411, causing the friction wheel 420 to retract into the window 320, preventing it from contacting the cardboard box. Figure 6 The diagram shown is a schematic of the retracted state.

[0062] To ensure structural reliability and stability, and to achieve energy conservation, the electromagnet 440 in this application is a de-energized electromagnet. It achieves magnetic attraction in the de-energized state and demagnetizes when energized. The model and voltage are selected according to the actual vehicle model; for example, the LSD-P20 / 23S model can be selected, with a length of 23mm, a diameter of 20mm, a magnetic force of 3KG, and a voltage of 12V or 24V. To better engage with the electromagnet 440, a magnetic attracting plate 450 is installed on the slide table.

[0063] In this application, to achieve the function of clamping goods with a large gap, a multi-stage guide rail system is used to drive the clamping arm. For details, please refer to... Figure 7 As shown, the clamping arm drive assembly 200 also includes a guide rail, which includes a primary guide rail 231, a guide rail seat 232, and a secondary guide rail 233. The guide rail seat 232 has T-shaped guide grooves 2321 formed on both sides of its cross-section to slidably connect the primary guide rail 231 (T-shaped) and the secondary guide rail 233 (T-shaped), respectively. Thus, the guide rail seat 232 slides on the primary guide rail 231, and the secondary guide rail 233 moves on the guide rail seat 232, achieving multi-stage extension and retraction. Similarly, in this application, the hydraulic cylinder 210 includes a primary hydraulic cylinder 211 and a secondary hydraulic cylinder 212. One end of the primary hydraulic cylinder 211 is connected to the primary guide rail 231, and the other end is connected to one end of the guide rail seat 232. One end of the secondary hydraulic cylinder 212 is connected to the other end of the guide rail seat 232, and the other end is connected to the secondary guide rail 233. Thus, when oil is injected into the primary hydraulic cylinder through the valve device, the primary hydraulic cylinder 211 is activated, driving the guide rail seat 232 to move outward. After the primary hydraulic cylinder 211 is filled with oil, the secondary hydraulic cylinder 212 begins to inject oil, pushing the secondary guide rail 233 to slide on the guide rail seat 232, thereby realizing the function of large-pitch movement and clamping of goods.

[0064] At this time, the oil pressure detection module 220 is installed in the oil supply circuit of the first-stage hydraulic cylinder 211.

[0065] Example 2

[0066] Another object of the present invention is to provide a forklift control method, please refer to... Figure 8 As shown, it is based on a carton clip as described in Example 1, which includes:

[0067] S1. Obtain the weight of the carton;

[0068] S2. Predict the coefficient of dynamic friction between the carton and the clamping arm 300;

[0069] S3. Calculate the clamping force based on the weight of the carton and the coefficient of dynamic friction, and output the clamping force to hold the carton.

[0070] S4. Obtain controller load data and determine whether the load data is greater than or equal to the carton weight. If not, proceed to S5; if yes, proceed to S6.

[0071] S5. Increase the clamping force by the preset increment, then return to S4;

[0072] S6. Determine whether encoder 430 has received an acceleration signal. If not, proceed to S7; if yes, proceed to S8.

[0073] S7. Reduce the clamping force according to the preset amount, then return to S6;

[0074] S8. The controller calculates the coefficient of dynamic friction based on the weight and acceleration of the carton, and corrects the clamping force based on the coefficient of dynamic friction.

[0075] In S1, the forklift obtains the weight of the carton (containing goods) through the passive radio frequency tag in the carton using an RFID reader; if there is no radio frequency tag in the carton, the gross weight stated on the carton can be entered on the forklift control screen; when there is no gross weight information for the carton, the weight of the goods is determined by estimating the weight of the goods, trying to clamp the goods until the goods are completely off the ground, reading the load data in the forklift controller.

[0076] In S2, the predicted value of the dynamic friction coefficient between the carton and the clamping arm 300 is determined by empirical value. Since the surface roughness of the friction plate 310 on the clamping arm 300 is relatively fixed, the dynamic friction coefficient with the most samples of dynamic friction coefficient distribution between the carton and the friction plate 310 within a certain period can be used as the empirical value. In other words, the initial dynamic friction coefficient can be determined by the most common carton type, such as initially setting it to 0.28.

[0077] In S3, the theoretical clamping force required to hold the carton can be calculated based on the carton weight and the estimated coefficient of kinetic friction.

[0078] That is, according to the equilibrium condition, when the carton is clamped and kept from sliding down, the frictional force is equal to the gravity. In other words, G = 2f, where G is the gravity and f is the frictional force exerted on the carton by the clamping arm 300.

[0079] Then, according to the friction force calculation formula f=μF N The clamping force F required to hold the carton can be calculated. N .

[0080] Then, in S4, the controller load data is obtained, and it is determined whether the load data is greater than or equal to the weight of the carton to determine whether the carton is completely clamped (lifted off the ground). If not, proceed to S5 to increase the clamping force; if yes, proceed to S6 for measurement.

[0081] In S6, it is determined whether the encoder 430 has obtained an acceleration signal. If not, the frictional force is greater than the gravity, and the carton is effectively clamped. At this time, it enters S7 and reduces the clamping force according to the preset reduction until the carton begins to slide down slowly. When the carton slides down, the acceleration value of the carton sliding down is obtained.

[0082] It is easy to understand that the acceleration value obtained here is the angular acceleration value, which should be converted into linear velocity, that is, V=ωr, where V is the linear velocity, ω is the angular velocity, and r is the radius of the friction wheel.

[0083] Thus, F 合 =2f-mg; Δv=F 合 / m;f=μF NSolving the system of equations, we have μ=(△v*m+mg) / 2F N The controller can then calculate the coefficient of dynamic friction based on the weight and acceleration of the carton.

[0084] Then, based on the coefficient of dynamic friction and the mass of the goods, the required minimum clamping force is calculated and corrected. Considering the error caused by the relative sliding factors between the friction wheel 420 and the carton on the acceleration value, as well as the inertia at the moment of forklift start and stop, etc., in order to ensure the reliability of clamping, this application assigns a safety factor x greater than 1 to the calculated minimum clamping force. This parameter can be flexibly set according to the carton material, such as setting the safety factor x to 1.1-1.2.

[0085] It is easy to understand that the coefficient of dynamic friction is usually less than the coefficient of static friction. Therefore, by calculating the coefficient of dynamic friction, this application can ensure that the carton is reliably clamped and that over-clamping is less likely to occur.

[0086] After determining the current carton clamping force, the acceleration detection module 400 retracts into the clamping arm 300 and no longer contacts the carton.

[0087] Furthermore, in a preferred embodiment, the number of stacking layers can also be determined based on the measured coefficient of dynamic friction, i.e., it includes S9, stacking risk warning.

[0088] Aside from irregularly shaped packaging, the following are some common reasons why cardboard boxes may tip over: 1. The product surface area is too small; 2. The stacking height is too high, causing the bottom product to be crushed and deformed, resulting in tipping over; 3. The coefficient of friction is low, with the static friction coefficient between the cardboard boxes being too small, resulting in low frictional force, and even slight external force or misalignment can cause the boxes to tip over.

[0089] Please refer to Figure 9 As shown, S9 specifically includes:

[0090] S91. Determine the aspect ratio of the carton. Check if the aspect ratio exceeds the threshold. If yes, proceed to S92; otherwise, the process terminates.

[0091] S92. Obtain the dynamic friction coefficient. Refer to the coefficient comparison table based on the dynamic friction coefficient to obtain the inter-carton dynamic friction coefficient corresponding to this dynamic friction coefficient in history.

[0092] S93. Calculate the sliding friction when the two cartons are stacked, and determine whether the sliding friction is less than the preset value. If so, output a risk warning of tipping over.

[0093] The width of the carton can be obtained visually or by controlling the gripper arm stroke. The height of the carton can be obtained visually. When visually inspecting, the width and height of the forklift can be used as a reference to determine the contact area of ​​the carton based on the width-to-height ratio. In other words, it determines whether the carton is a tall and narrow type or a flat type. For tall and narrow products, they are not suitable for stacking, and the process ends. For flat types, it proceeds to S92.

[0094] While it's easy to understand that the coefficient of kinetic friction between cartons cannot be directly derived from the coefficient of kinetic friction between the clamping arm 300 and the cartons, the coefficient of kinetic friction between the friction plate 310 and each carton can be measured. This allows for the establishment of a correspondence, obtaining a coefficient lookup table to retrieve the historical coefficient of kinetic friction between cartons. In other words, by using calibrated data, the coefficients of kinetic friction between cartons and between cartons and the friction plate 310 are equivalently correlated. Thus, based on the measured coefficient of kinetic friction between cartons and the friction plate 310, the coefficient of kinetic friction between cartons can be predicted. Furthermore, based on the weight of a single carton and the coefficient of kinetic friction between cartons, the sliding friction force between cartons can be calculated, effectively calculating the force required to push the cartons. When the sliding friction force is less than a preset value, a risk warning for cartons tipping over is issued.

[0095] It is easy to understand that when consulting the coefficient of kinetic friction table, the currently measured coefficient of kinetic friction μ 实 Often, the coefficient μ is consulted in a coefficient comparison table for the coefficient of kinetic friction. 表 They do not match perfectly. In this case, if the difference Δμ = μ 实 -μ 表 Within a certain threshold range, they are considered equal.

[0096] Accordingly, another object of the present invention is to provide a forklift controller, including a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program, it implements the forklift control method as described in Embodiment 2.

[0097] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0098] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0099] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0100] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0101] It should be noted that any reference signs placed between parentheses in the claims should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first-level, second-level, etc., does not indicate any order. These words can be interpreted as names.

[0102] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0103] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0104] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0105] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A forklift control method, characterized in that: A carton clamp is configured for a forklift. The carton clamp includes a rear-mounted assembly, a clamping arm drive assembly, and a pair of clamping arms. The clamping arm drive assembly includes a hydraulic cylinder and a hydraulic pressure detection module. The hydraulic cylinder drives the clamping arms to clamp the carton, and the hydraulic pressure detection module detects the current clamping force of the hydraulic cylinder. One of the clamping arms has a window for installing an acceleration detection module. The acceleration detection module includes a telescopic base, a friction wheel, and an encoder. The telescopic base is elastically arranged perpendicular to the clamping arm. The friction wheel is mounted on the telescopic base and has a portion extending outward from the inner side of the clamping arm under the action of the telescopic base. The encoder is coaxially arranged with the friction wheel to obtain the acceleration of the friction wheel to detect the acceleration of the carton as it slides down the clamping arm. The hydraulic pressure detection module and the acceleration detection module send their detection values ​​to a controller, which calculates the dynamic friction coefficient between the carton and the clamping arm to control the clamping arm drive assembly to output a clamping force adapted to the carton. Control methods include: S1. Obtain the weight of the carton; S2. Predict the coefficient of dynamic friction between the carton and the clamping arm; S3. Calculate the clamping force based on the weight of the carton and the coefficient of dynamic friction, and output the clamping force to hold the carton. S4. Obtain controller load data and determine whether the load data is greater than or equal to the carton weight. If not, proceed to S5; if yes, proceed to S6. S5. Increase the clamping force by the preset increment, then return to S4; S6. Determine whether the encoder has received an acceleration signal. If not, proceed to S7; if yes, proceed to S8. S7. Reduce the clamping force according to the preset amount, then return to S6; S8. The controller calculates the coefficient of dynamic friction based on the weight and acceleration value of the carton, and corrects the clamping force based on the coefficient of dynamic friction. The clamping arm drive assembly outputs a clamping force adapted to the carton. S9. Risk assessment of stacking failure; S91. Determine the aspect ratio of the carton. Check if the aspect ratio exceeds the threshold. If yes, proceed to S92; otherwise, the process terminates. S92. Obtain the dynamic friction coefficient. Refer to the coefficient comparison table based on the dynamic friction coefficient to obtain the inter-carton dynamic friction coefficient corresponding to this dynamic friction coefficient in history. S93. Calculate the sliding friction when two cartons are stacked, and determine whether the sliding friction is less than the preset value. If so, output a risk warning of stacking failure.

2. The forklift control method as described in claim 1, characterized in that: The encoder is a shaft-mounted encoder, and the friction wheels are a pair and are located on both sides of the encoder. The diameter of the encoder is smaller than the diameter of the friction wheels.

3. The forklift control method as described in claim 1, characterized in that: The telescopic seat is a linear slide, and a spring is provided between the slide rod and the slide to achieve elastic setting.

4. The forklift control method as described in claim 3, characterized in that: An electromagnet is provided in the seat of the telescopic seat. When the electromagnet attracts the slide, the slide retracts against the elastic force of the spring, causing the friction wheel to retract into the window.

5. The forklift control method as described in claim 4, characterized in that: The electromagnet is a de-energized electromagnet.

6. The forklift control method as described in claim 1, characterized in that: The clamping arm drive assembly also includes a guide rail, which includes a primary guide rail, a guide rail seat, and a secondary guide rail. Guide grooves are formed on both sides of the cross-section of the guide rail seat to slidably connect the primary guide rail and the secondary guide rail, respectively. The hydraulic cylinder includes a primary hydraulic cylinder and a secondary hydraulic cylinder. One end of the primary hydraulic cylinder is connected to the primary guide rail, and the other end is connected to one end of the guide rail seat. One end of the secondary hydraulic cylinder is connected to the other end of the guide rail seat, and the other end is connected to the secondary guide rail.

7. A forklift controller, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor runs the computer program, it implements the forklift control method as described in claim 1.

Images