Forklift advancing speed control method and system

Abstract

The invention provides a forklift advancing speed control method and system, and relates to the technical field of forklift control, and the method comprises the steps that the forklift rollover critical condition of a forklift in the turning process is determined; solving the maximum safety speed of the forklift; the forklift sideslip critical speed of the forklift in the turning process is determined; correcting the maximum safety speed of the forklift by using the sideslip critical speed of the forklift; the forklift roll angle, the forklift angular speed, the forklift actual speed and the forklift front wheel steering angle are obtained; based on the front wheel steering angle of the forklift, the current forklift turning radius is calculated through an Ackerman steering geometric model; the forklift maximum safety speed correction value corresponding to the current forklift turning radius is determined; a PD controller is used for conducting secondary correction on the forklift maximum safety speed correction value corresponding to the current forklift turning radius, and the forklift advancing speed upper limit value is output; and the actual speed of the forklift is adjusted according to the forklift advancing speed upper limit value, and advancing speed control over the forklift is completed. And the advancing safety of the forklift is ensured and the working efficiency of the forklift is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of forklift control, and particularly to a method and system for controlling the traveling speed of a forklift. Background Art

[0002] A forklift is a common industrial vehicle mainly used for carrying goods. It usually has two adjustable fork arms for carrying and lifting goods, and is widely used in places such as warehouses, distribution centers, factories, and construction sites. The forklift controls forward and backward through its drive system and steering gear, and can operate efficiently in narrow spaces.

[0003] During the working process of a forklift, precise control of the traveling speed is required to ensure the safety and efficiency of goods handling. If the speed is too fast, it may tip over, causing the goods to fall or be damaged, and even accidents may occur; precise speed control can effectively avoid dangerous situations such as tipping over and skidding caused by improper operation, ensure the safety of the forklift and the staff, and improve the overall work efficiency. Therefore, reasonable control of the traveling speed is crucial for the safe and efficient operation of the forklift.

[0004] However, existing forklifts often do not have active control of the traveling speed of the forklift, resulting in problems such as skidding or tipping over caused by improper operation of the operator during the working process of the forklift, and there are serious safety risks. Summary of the Invention

[0005] In order to solve the technical problem that existing forklifts often do not have active control of the traveling speed of the forklift, resulting in problems such as skidding or tipping over caused by improper operation of the operator during the working process of the forklift, and there are serious safety risks, the present invention provides a method and system for controlling the traveling speed of a forklift.

[0006] The technical solutions provided by the embodiments of the present invention are as follows:

[0007] First Aspect

[0008] A method for controlling the traveling speed of a forklift provided by an embodiment of the present invention, the method includes:

[0009] S1: Determine the critical tipping condition of the forklift during the turning process based on the mechanical equilibrium equation;

[0010] S2: Solve the critical tipping speed of the forklift under the critical tipping condition, that is, the maximum safe speed of the forklift;

[0011] S3: Combine the road surface where the forklift travels to determine the critical skidding speed of the forklift during the turning process;

[0012] S4: Use the critical skidding speed of the forklift to correct the maximum safe speed of the forklift to obtain the corrected value of the maximum safe speed of the forklift;

[0013] S5: Obtain the forklift roll angle, forklift angular velocity, forklift actual speed, and forklift front wheel steering angle;

[0014] S6: Based on the forklift front wheel steering angle, calculate the current forklift turning radius through the Ackermann steering geometry model;

[0015] S7: Determine the correction value of the maximum safe speed of the forklift corresponding to the current forklift turning radius;

[0016] S8: Perform secondary correction on the correction value of the maximum safe speed of the forklift corresponding to the current forklift turning radius through a PD controller, and output the upper limit value of the forklift traveling speed;

[0017] S9: Adjust the actual speed of the forklift according to the upper limit value of the forklift traveling speed to complete the control of the forklift traveling speed.

[0018] Second aspect

[0019] A forklift traveling speed control system provided by an embodiment of the present invention includes:

[0020] A processor;

[0021] A memory, on which computer-readable instructions are stored, and when the computer-readable instructions are executed by the processor, the forklift traveling speed control method described in the first aspect is implemented.

[0022] Third aspect

[0023] A computer-readable storage medium provided by an embodiment of the present invention, on which a computer program is stored, and when the program is executed by a processor, the forklift traveling speed control method described in the first aspect is implemented.

[0024] The beneficial effects brought by the technical solutions provided by the embodiments of the present invention at least include:

[0025] In the embodiments of the present invention, based on various factors such as the mechanical equilibrium equation, the rollover critical condition, and the road surface friction coefficient, the maximum safe speed of the forklift is dynamically calculated and corrected to ensure that the forklift will not overspeed during the turning process, and to avoid safety hazards such as skidding or rollover caused by too fast or inappropriate speed. By real-time obtaining the forklift roll angle, angular velocity, actual speed, and front wheel steering angle, and combining with the Ackermann steering geometry model to calculate the turning radius, and further precisely adjusting the upper limit value of the traveling speed through a PD controller, the stability and safety of the forklift in different working environments are ensured, thereby effectively preventing dangers caused by improper operation of the operator. This method has obvious advantages in dynamic adjustment and precise control, and improves the safety, operation efficiency, and adaptability of the forklift. Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 A schematic flow chart of a forklift travel speed control method provided by an embodiment of the present invention;

[0028] Figure 2 A schematic structural diagram of a forklift travel speed control system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0030] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0031] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0032] Reference Manual Attached Figure 1 , which shows a flow chart of a forklift travel speed control method provided by an embodiment of the present invention.

[0033] An embodiment of the present invention provides a method for controlling the travel speed of a forklift. The processing flow of the method for controlling the travel speed of a forklift may include the following steps:

[0034] S1: Determine the critical conditions for the forklift to roll over during the turning process based on the mechanical equilibrium equation.

[0035] Among them, the critical condition for forklift rollover refers to the situation in which the forklift may roll over when the driving speed and turning radius of the forklift reach a certain critical value during the turning process of the forklift. The critical condition for rollover based on the mechanical equilibrium equation provides a scientific speed limit basis for the forklift, which can avoid the risk of rollover caused by overspeeding when the forklift turns. This method can dynamically calculate and accurately determine whether the forklift is close to the critical state of rollover, thereby providing important data support for subsequent speed control and effectively improving the safety of forklift operation.

[0036] In a possible implementation, the rollover critical condition is specifically as follows:

[0037]

[0038] Among them, m represents the total mass of the forklift, v represents the traveling speed of the forklift, r represents the turning radius of the forklift, h represents the center height of the forklift, g represents the acceleration due to gravity, and l represents the wheelbase of the forklift.

[0039] It should be noted that by calculating the rollover critical condition of the forklift based on the mechanical equilibrium equation, the stability of the forklift during turning can be scientifically evaluated. This formula comprehensively considers factors such as the mass, traveling speed, turning radius, center height, and wheelbase of the forklift, and can accurately determine whether the forklift will roll over under different working conditions. This method provides a scientific basis for forklift speed control, can effectively avoid the rollover risk caused by overspeed, and improve the safety of the forklift during turning.

[0040] S2: Solve the rollover critical speed of the forklift under the rollover critical condition, that is, the maximum safe speed of the forklift.

[0041] It should be noted that by solving the maximum safe speed of the forklift under the rollover critical condition, it can ensure that the forklift remains within the safe speed range during turning and avoid rollover caused by excessive speed. By calculating the maximum safe speed, a clear speed limit can be provided for forklift operation, ensuring that the forklift can travel stably under different working conditions, reducing the risk of accidents, and improving safety and operation reliability.

[0042] In a possible implementation, the calculation formula for the maximum safe speed of the forklift is specifically as follows:

[0043]

[0044] Among them, v max represents the maximum safe speed of the forklift.

[0045] It should be noted that by calculating the maximum safe speed of the forklift using this formula, the maximum safe speed of the forklift during turning can be accurately estimated based on factors such as the turning radius, acceleration due to gravity, wheelbase, and center height of the forklift. This method can dynamically provide speed limits to ensure that the forklift does not overspeed during turning, thus effectively avoiding the rollover risk caused by excessive speed. By reasonable speed control, the safety and stability of forklift operation are improved, and potential accidents are reduced.

[0046] S3: Determine the side slip critical speed of the forklift during turning in combination with the road surface where the forklift travels.

[0047] Among them, the critical speed of forklift side slip refers to the speed at which, during the turning process of a forklift, when its driving speed exceeds this value, the frictional force between the tire and the road surface is insufficient to resist the centrifugal force, resulting in the forklift experiencing side slip. Side slip will cause the forklift to lose stability and increase the risk of tipping over or hitting. Generally, the critical speed of side slip is related to factors such as the road surface friction coefficient, the turning radius of the forklift, and the grip of the tire. By combining the friction coefficient of the road surface on which the forklift travels to determine the critical speed of side slip, the influence of different road surface conditions on the stability of the forklift is effectively considered. In this way, the speed limit can be dynamically adjusted according to the actual road surface conditions to prevent side slip caused by insufficient road surface friction, ensuring the stability and safety of the forklift during the turning process and further reducing the operation risk.

[0048] In a possible implementation manner, the specific calculation formula for the critical speed of forklift side slip is as follows:

[0049]

[0050] Among them, μ represents the friction coefficient of the road surface on which the forklift travels.

[0051] It should be noted that the side slip threshold of the forklift is dynamically determined according to the road surface friction coefficient, gravitational acceleration, and turning radius. The influence of the road surface conditions on the stability of the forklift is fully considered, and the speed limit can be adjusted according to the actual road surface friction to prevent the forklift from side slipping due to insufficient friction during turning. This can effectively improve the safety of the forklift under different working conditions and reduce the accident risk caused by side slip.

[0052] S4: Use the critical speed of forklift side slip to correct the maximum safe speed of the forklift to obtain the corrected value of the maximum safe speed of the forklift.

[0053] It should be noted that by introducing the critical speed of side slip into the correction of the maximum safe speed, it is ensured that the forklift will neither tip over nor side slip during the turning process. This correction can dynamically adjust the driving speed of the forklift according to the actual road surface conditions and turning characteristics, avoiding potential safety hazards caused by excessive speed. Through this measure, the forklift can operate stably under a wider range of environmental conditions, improving overall safety and reducing risks caused by improper operation or environmental changes.

[0054] In a possible implementation manner, the specific calculation method for the corrected value of the maximum safe speed of the forklift is as follows:

[0055] v' max =min(v max ,V 侧滑 )

[0056] Among them, v' max represents the corrected value of the maximum safe speed of the forklift.

[0057] It should be noted that the maximum safety speed correction value of the forklift is calculated by comprehensively considering the maximum safety speed of the forklift and the road surface friction conditions. This correction method ensures that the driving speed of the forklift does not exceed the critical skidding speed and does not exceed the maximum safety speed of the forklift, thereby avoiding skidding and rollover phenomena during the turning process. In this way, the speed limit of the forklift can be dynamically adjusted according to the actual road conditions, enhancing the stability and safety of the forklift and preventing safety risks caused by excessive speed.

[0058] S5: Obtain the forklift roll angle, forklift angular velocity, forklift actual speed, and forklift front wheel steering angle.

[0059] Specifically, the forklift roll angle and forklift angular velocity can be obtained through a gyroscope. The forklift actual speed and forklift front wheel steering angle can be obtained through an encoder.

[0060] S6: Based on the forklift front wheel steering angle, calculate the current forklift turning radius through the Ackermann steering geometry model.

[0061] Among them, the Ackermann steering geometry model is a geometric model used to describe the turning behavior of a vehicle with front-wheel steering. Its core principle is to ensure that when the vehicle turns, the inner and outer wheels travel along different trajectories, and through geometric angle calculations, the steering angles of the wheels can ensure the vehicle turns smoothly. The design of the Ackermann steering geometry model enables the vehicle to avoid unnecessary sliding of the inner and outer tires during the turning process, improving the stability and controllability of turning. By accurately calculating the turning radius based on the forklift front wheel steering angle and the Ackermann steering geometry model, the steering angle and turning radius required by the forklift during the turning process can be accurately estimated, thereby optimizing the handling performance of the forklift. This calculation helps to predict the movement trajectory and stability of the forklift when turning, providing accurate data for subsequent adjustment of the traveling speed, and effectively improving the safety and operation efficiency of the forklift during the turning process.

[0062] In a possible implementation manner, the calculation method of the current forklift turning radius is specifically as follows:

[0063]

[0064] Among them, r now represents the current forklift turning radius, tan represents the tangent function, β represents the forklift front wheel steering angle, and d represents the forklift wheelbase, that is, the distance between the front and rear wheels of the forklift.

[0065] It should be noted that dynamically determining the turning radius according to the forklift front wheel steering angle and wheelbase accurately reflects the geometric characteristics of the forklift during the turning process, and can calculate the turning radius in real time, providing accurate motion data. This helps to optimize the handling performance of the forklift, ensure the stability of the forklift under different turning conditions, and thus improve the operation safety.

[0066] S7: Determine the forklift maximum safe speed correction value corresponding to the current forklift turning radius.

[0067] Specifically, the current forklift turning radius can be substituted into the calculation formula of the forklift maximum safe speed correction value to calculate the corrected forklift maximum safe speed corresponding to the current forklift turning radius.

[0068] It can be understood that by substituting the turning radius of the current forklift into the calculation formula of the maximum safe speed correction value, the safe speed limit of the forklift can be dynamically adjusted according to the actual turning radius. This method ensures that the forklift can maintain stability at different turning radii and avoids overspeed problems caused by too small or too large turning radii. Through this precise adjustment, the forklift can operate at a speed that adapts to different working conditions and turning requirements while ensuring safety, significantly improving the safety and flexibility of operation.

[0069] S8: Perform secondary correction on the forklift maximum safe speed correction value corresponding to the current forklift turning radius through a PD controller, and output the upper limit value of the forklift traveling speed.

[0070] Among them, the PD controller is a common feedback controller, which consists of two parts: proportional (P) and derivative (D). The proportional part adjusts according to the current error, and the derivative part adjusts according to the change rate of the error. Proportional control enables the system to directly respond to the error, while derivative control helps the system predict the future error trend, thereby reducing system oscillation and overshoot. The PD controller is commonly used for dynamic adjustment to improve the response speed and stability of the system.

[0071] It should be noted that by using the PD controller to perform secondary correction on the maximum safe speed, the upper limit of the traveling speed can be dynamically adjusted according to the real-time state and error of the forklift. The proportional part ensures that the forklift promptly responds to the current gap in speed, and the derivative part helps suppress speed fluctuations caused by environmental changes or improper operations. Through this dual adjustment, the forklift can operate at a more stable and precise speed, improving the stability and safety during turning and ensuring that the forklift meets the requirements of different working conditions.

[0072] In a possible implementation manner, the calculation method of the upper limit value of the forklift traveling speed is specifically:

[0073] v target = v′ max (r now ) - Δv

[0074]

[0075] Among them, v′ max (r now)Indicates the current turning radius r of the forklift now The corresponding maximum safe speed correction value of the forklift, v target Indicates the upper limit value of the forklift traveling speed, K p And K v Respectively represent the proportional gain and the derivative gain. ψ represents the roll angle of the forklift, ψ ref Indicates the safe threshold of the forklift roll angle Indicates the rate of change of the forklift roll angle measured by the gyroscope

[0076] It should be noted that by combining the proportional gain and the derivative gain adjustment, the upper speed limit can be dynamically corrected according to the roll angle and angular velocity of the forklift. Such a method can monitor the stability of the forklift in real time, ensure that the traveling speed is automatically reduced when the roll angle approaches the safe threshold, and prevent the rollover risk caused by overspeed. By adjusting the gain, the system can adapt to different operating conditions, thereby optimizing the safety and operating accuracy of the forklift in complex environments.

[0077] Optionally, the safe threshold of the forklift roll angle can be set to 3°. It can be specifically set according to actual needs.

[0078] S9: Adjust the actual speed of the forklift according to the upper limit value of the forklift traveling speed to complete the control of the forklift traveling speed.

[0079] In a possible implementation manner, S9 is specifically:

[0080] When the actual speed of the forklift is greater than the upper limit value of the forklift traveling speed, control the actual speed of the forklift to be adjusted to the upper limit value of the forklift traveling speed; otherwise, keep the actual speed of the forklift unchanged.

[0081] It can be understood that adjusting the actual speed of the forklift according to the upper limit value of the forklift traveling speed can ensure that the forklift does not overspeed during turning or other operations, thereby avoiding the rollover or sideslip risk caused by excessive speed. When the actual speed of the forklift exceeds the safety upper limit, the system will automatically adjust the speed to ensure the safety and stability of the operation. When the forklift speed is lower than the upper limit, no intervention is required and it keeps working normally. This dynamic adjustment can guarantee the safety of the forklift in real time according to the actual working conditions, avoiding dangers caused by human errors or environmental changes.

[0082] In the actual application process, first, the rollover critical condition of the forklift is determined through the mechanical equilibrium equation, and then the maximum safe speed is calculated. In step S3, the critical speed of the forklift for sideslip is determined in combination with the road surface friction coefficient and used to correct the maximum safe speed to ensure that sideslip is prevented while avoiding rollover. Then, various state data of the forklift, such as the roll angle, speed, and front wheel steering angle, are obtained in real time through sensors. Then, based on the Ackermann steering geometry model, the current turning radius is calculated, and further, the maximum safe speed of the forklift is corrected according to the turning radius to ensure stability under different working conditions. Next, a PD controller is used to perform secondary adjustment on the corrected safe speed to improve the responsiveness and accuracy. Finally, the actual driving speed of the forklift is adjusted according to the calculated upper limit of the traveling speed to achieve precise path control. This process dynamically intervenes in the traveling speed of the forklift through a multi-feedback and dynamic adjustment mechanism, improving the safety and flexibility of the forklift during driving and reducing the operation risk.

[0083] The beneficial effects brought by the technical solution provided in the embodiment of the present invention at least include:

[0084] In the embodiment of the present invention, based on various factors such as the mechanical equilibrium equation, rollover critical condition, and road surface friction coefficient, the maximum safe speed of the forklift is dynamically calculated and corrected to ensure that the forklift will not exceed the speed during turning and avoid safety hazards such as sideslip or rollover caused by too fast or inappropriate speed. By obtaining the roll angle, angular velocity, actual speed, and front wheel steering angle of the forklift in real time and combining the Ackermann steering geometry model to calculate the turning radius, and further precisely adjusting the upper limit value of the traveling speed through a PD controller, the stability and safety of the forklift under different working environments are ensured, thus effectively preventing dangers caused by improper operation of the operator. This method has obvious advantages in dynamic adjustment and precise control, improving the safety, operation efficiency, and adaptability of the forklift.

[0085] Refer to the attached Figure 2 illustration, which shows the structural schematic diagram of a forklift traveling speed control system provided by the present invention.

[0086] The present invention also provides a forklift traveling speed control system 20, which is applied to the above-mentioned forklift traveling speed control method and includes:

[0087] A processor 201.

[0088] A memory 202, on which computer-readable instructions are stored. When the computer-readable instructions are executed by the processor 201, the forklift traveling speed control method as in the method embodiment is implemented.

[0089] The forklift traveling speed control system 20 provided by the present invention can execute the above-mentioned forklift traveling speed control method and achieve the same or similar technical effects. To avoid repetition, the present invention will not elaborate further.

[0090] The beneficial effects brought by the technical solution provided by the embodiments of the present invention at least include:

[0091] In the embodiments of the present invention, based on various factors such as the mechanical equilibrium equation, the rollover critical condition, and the road surface friction coefficient, the maximum safe speed of the forklift is dynamically calculated and corrected to ensure that the forklift does not exceed the speed limit during the turning process, and to avoid safety hazards such as skidding or rollover caused by excessive or inappropriate speeds. By obtaining the forklift's roll angle, angular velocity, actual speed, and front wheel steering angle in real time, and combining with the Ackermann steering geometry model to calculate the turning radius, and further precisely adjusting the upper limit value of the traveling speed through a PD controller, the stability and safety of the forklift in different working environments are ensured, thus effectively preventing dangers caused by improper operation of the operator. This method has obvious advantages in dynamic adjustment and precise control, improving the safety, operation efficiency, and adaptability of the forklift.

[0092] It should be understood that the processor in the embodiments of the present invention may be a central processing unit (CPU), and this processor may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or this processor may also be any conventional processor, etc.

[0093] It should also be understood that the memory in the embodiments of the present invention may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0094] The above embodiments can be implemented in whole or in part by software, hardware (such as circuits), firmware, or any combination thereof. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the processes or functions described in the embodiments of the present invention are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wired (such as infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that contains one or more collections of available media. The available media can be magnetic media (such as floppy disks, hard disks, magnetic tapes), optical media (such as DVDs), or semiconductor media. The semiconductor media can be a solid-state drive.

[0095] It should be understood that the term "and / or" in this document is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Here, A and B can be singular or plural. In addition, the character " / " in this document generally represents an "or" relationship between the associated objects before and after, but it may also represent an "and / or" relationship, which can be specifically understood with reference to the context.

[0096] In the present invention, "at least one" means one or more, and "a plurality" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can represent: a, b, c, a - b, a - c, b - c, or a - b - c, where a, b, and c can be single or multiple.

[0097] It should be understood that in various embodiments of the present invention, the magnitudes of the serial numbers of the above processes do not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0098] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0099] Those skilled in the art can clearly understand that for the convenience and conciseness of description, the specific working processes of the devices, apparatuses, and units described above can refer to the corresponding processes in the foregoing method embodiments, and will not be repeated herein.

[0100] In several embodiments provided by the present invention, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection to each other can be through some interfaces, and the indirect coupling or communication connection of the devices or units can be in an electrical, mechanical, or other form.

[0101] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place, or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0102] In addition, the functional units in each embodiment of the present invention can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0103] When the above-mentioned functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks, or optical discs that can store program codes.

[0104] An embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, it implements the forklift travel speed control method as described in the method embodiment.

[0105] The computer-readable storage medium provided by the present invention can implement the steps and effects of the forklift travel speed control method in the above method embodiment. To avoid repetition, the present invention will not elaborate further.

[0106] The beneficial effects brought by the technical solution provided by the embodiments of the present invention at least include:

[0107] In the embodiments of the present invention, based on various factors such as the mechanical equilibrium equation, the rollover critical condition, and the road surface friction coefficient, the maximum safe speed of the forklift is dynamically calculated and corrected to ensure that the forklift does not exceed the speed during the turning process, and to avoid safety hazards such as skidding or rollover caused by too fast or inappropriate speed. By real-time obtaining the forklift roll angle, angular velocity, actual speed, and front wheel steering angle, and combining with the Ackermann steering geometry model to calculate the turning radius, and further precisely adjusting the upper limit value of the travel speed through a PD controller, the stability and safety of the forklift in different working environments are ensured, thereby effectively preventing dangers caused by improper operation of the operator. This method has obvious advantages in dynamic adjustment and precise control, improving the safety, operation efficiency, and adaptability of the forklift.

[0108] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

[0109] The following points need to be explained:

[0110] (1) The accompanying drawings of the embodiments of the present invention only relate to the structures involved in the embodiments of the present invention, and other structures may refer to the general design.

[0111] (2) For clarity, in the accompanying drawings used to describe the embodiments of the present invention, the thickness of layers or regions is enlarged or reduced, that is, these drawings are not drawn to actual scale. It can be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "under" another element, the element can be "directly" on or under the other element or there may be intermediate elements.

[0112] (3) Without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

[0113] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for controlling the travel speed of a forklift, characterized in that the method include: Determining a critical condition for the forklift to roll over during a turn based on a mechanical equilibrium equation; Solve the forklift rollover critical speed under the rollover critical condition, that is, the maximum safe speed of the forklift; Determining the forklift's side slip critical speed during a turn based on the road surface on which the forklift is traveling; The maximum safety speed of the forklift is corrected by using the forklift sideslip critical speed to obtain a maximum safety speed correction value of the forklift; Obtain the forklift's roll angle, angular velocity, actual speed and front wheel steering angle of the forklift; Based on the forklift front wheel steering angle, the current forklift turning radius is calculated by using the Ackerman steering geometry model; Determine the maximum safe speed correction value of the forklift corresponding to the current forklift turning radius; The PD controller performs a secondary correction on the maximum safe speed correction value of the forklift corresponding to the current forklift turning radius, and outputs the upper limit of the forklift travel speed; The actual speed of the forklift is adjusted according to the upper limit value of the forklift's travel speed to complete the travel speed control of the forklift.

2. The forklift travel speed control method according to claim 1, characterized in that: The rollover critical condition is specifically: Among them, m represents the total mass of the forklift, v represents the travel speed of the forklift, r represents the turning radius of the forklift, h represents the center height of the forklift, g represents the acceleration of gravity, and l represents the left and right wheelbase of the forklift.

3. The forklift travel speed control method according to claim 1, characterized in that: The calculation formula for the maximum safe speed of the forklift is specifically: Among them, v max Indicates the maximum safe speed of the forklift.

4. The forklift travel speed control method according to claim 1, characterized in that: The calculation formula of the forklift side slip critical speed is specifically: Wherein, μ represents the friction coefficient of the road surface on which the forklift is traveling.

5. The forklift travel speed control method according to claim 4, characterized in that: The calculation method of the maximum safe speed correction value of the forklift is specifically as follows: v' max =min(v max ,V 侧滑 ); Among them, v' max Indicates the maximum safe speed correction value of the forklift.

6. The forklift travel speed control method according to claim 1, characterized in that: The current calculation method of the forklift turning radius is as follows: Among them, r now represents the current turning radius of the forklift, tan represents the tangent function, β represents the steering angle of the front wheels of the forklift, and d represents the wheelbase of the forklift, that is, the distance between the front and rear wheels of the forklift.

7. The forklift travel speed control method according to claim 1, characterized in that: The calculation method of the upper limit of the forklift speed is specifically as follows: v target =v′ max (r now )-Δv; Among them, v′ max (r now ) represents the current forklift turning radius r now The corresponding maximum safe speed correction value of the forklift is v target Indicates the upper limit of the forklift's travel speed, K p and K v Represent the proportional gain and differential gain respectively, ψ represents the forklift roll angle, ψ ref Indicates the safety threshold of the forklift's roll angle. Indicates the forklift's roll angle rate measured by the gyroscope.

8. The forklift travel speed control method according to claim 1, characterized in that: The actual speed of the forklift is adjusted according to the upper limit of the forklift speed to complete the speed control of the forklift, specifically: When the actual speed of the forklift is greater than the upper limit of the forklift travel speed, the actual speed of the forklift is controlled to be adjusted to the upper limit of the forklift travel speed; otherwise, the actual speed of the forklift is maintained unchanged.

9. A forklift travel speed control system, characterized in that: include: processor; A memory having computer-readable instructions stored thereon, wherein when the computer-readable instructions are executed by the processor, the forklift travel speed control method according to any one of claims 1 to 8 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the forklift travel speed control method according to any one of claims 1 to 8 is implemented.

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