Steering semi-automatic control method and device for telescopic handler

Abstract

The application relates to a steering semi-automatic control method and device for a telescopic forklift truck, wherein a front wheel steering mode, an all-wheel steering mode and a crab steering mode are preset, and an independent rear wheel steering mode is not set. The method comprises the following steps: receiving a target mode instruction; judging whether the target mode instruction is consistent with a current mode; when the target mode instruction is not consistent with the current mode, switching to a transition mode capable of driving the rear axle to actively steer first, and then performing a rear axle centering correction; switching to a front wheel mode capable of driving the front axle to actively steer; and automatically switching to the target mode after the switching is completed. The scheme simplifies operation, improves efficiency, eliminates safety hazards from the architecture, and reduces cost and failure rate.

Description

Technical Field

[0001] This application relates to the field of engineering machinery technology, and in particular to a semi-automatic steering control method and device for telescopic boom forklifts. Background Technology

[0002] Telescopic boom forklifts are multi-functional engineering machines that integrate forking, lifting, and short-distance transportation, and are widely used in construction, agriculture, mining, and other fields. The performance of its steering system directly affects the machine's operating efficiency, maneuverability, and driving safety.

[0003] Currently, telescopic boom forklifts typically have three standard steering modes: front-wheel steering, all-wheel steering, and crab steering, to meet the mobility requirements under different operating conditions. Front-wheel steering is used for high-speed relocation to ensure driving stability; all-wheel steering achieves the smallest turning radius by deflecting the front and rear wheels in opposite directions, making it suitable for narrow spaces; crab steering achieves lateral translation of the entire vehicle by deflecting the front and rear wheels in the same direction, facilitating precise positioning.

[0004] Traditional steering mode switching schemes are mostly manual. The operator needs to select the target mode using a joystick or switch, observe the tire direction indicator, and confirm that both the front and rear axles are aligned before a successful switch can occur. This manual switching method has the following problems: First, the switching process is cumbersome, relying heavily on the operator's experience and judgment. Especially in operating environments with severe vehicle vibration, capturing and confirming the alignment signal is difficult, leading to switching failures or excessively long switching times, thus affecting operational efficiency. Second, some designs, in pursuit of comprehensive functionality, reserve valve assemblies and pipelines in the hydraulic circuit for an independent rear-wheel steering mode. However, for equipment like telescopic boom forklifts with high centers of gravity, large loads, and variable boom lengths, an independent rear-wheel steering mode can cause the vehicle to exhibit fishtailing characteristics during travel, easily leading to rollover accidents and posing serious safety hazards. Furthermore, the addition of redundant hydraulic components increases system complexity, manufacturing costs, and failure rates. Summary of the Invention

[0005] Therefore, it is necessary to provide a semi-automatic steering control method and device for telescopic boom forklifts to address the aforementioned technical problems.

[0006] A semi-automatic steering control method for telescopic boom forklifts is applied to a steering control system, wherein the steering control system presets multiple steering modes, including at least a front-wheel steering mode, an all-wheel steering mode, and a crab steering mode, but does not set a separate rear-wheel steering mode; the method includes:

[0007] Receive the target steering mode selection command issued by the operator; In response to the selection command, determine whether the current steering mode is consistent with the target steering mode; If there is a discrepancy, the current steering mode will be switched to a transition mode based on a preset control strategy, and a rear axle centering correction operation will be performed; wherein, the transition mode is one of an all-wheel steering mode or a crab steering mode that can drive the rear axle to actively steer. After confirming that the rear axle has completed centering correction, the transition mode is switched to the front wheel steering mode; after confirming that the front axle has completed centering correction, the target steering mode is successfully switched; the transition mode is switched to the target steering mode. The rear axle alignment correction operation includes: obtaining the center position state of the rear axle through a detection device, and controlling the rear axle steering cylinder to move based on the center position state until the rear axle returns to the preset alignment position. The front axle alignment correction operation includes: obtaining the center position state of the front axle through a detection device, and controlling the front axle steering cylinder to move based on the center position state until the front axle returns to the preset alignment position.

[0008] In one embodiment, the step of switching the current steering mode to a transition mode based on a preset control strategy includes: when the current steering mode is a front-wheel steering mode and the target steering mode is an all-wheel steering mode or a crab steering mode, selecting the target steering mode as the transition mode, and performing a rear axle centering correction operation to switch the transition mode to the front-wheel steering mode; after confirming that the front axle has completed the centering correction, successfully switching to the target steering mode.

[0009] In one embodiment, the step of switching the current steering mode to a transition mode based on a preset control strategy specifically includes: when the current steering mode is an all-wheel steering mode and the target steering mode is a crab steering mode, or when the current steering mode is a crab steering mode and the target steering mode is an all-wheel steering mode, selecting the current steering mode as the transition mode, and after performing a rear axle alignment correction operation, switching the transition mode to the front wheel steering mode; and after confirming that the front axle has completed alignment correction, successfully switching to the target steering mode.

[0010] In one embodiment, the step of switching the current steering mode to a transition mode based on a preset control strategy further includes: obtaining the current steering wheel angle position information or the steering angle information of the front and rear axles; when the steering wheel is in a non-neutral state or the steering angle of the front and rear axles has not returned to center, selecting the corresponding transition mode according to the steering wheel angle position information or the steering angle information, so that the rear axle has a tendency or path to move towards the center position before performing centering correction.

[0011] In one embodiment, the hydraulic circuit of the steering control system includes only a three-position four-way valve for switching between the all-wheel steering mode and the crab steering mode, and does not include a two-position four-way valve for locking the front wheels to form an independent rear wheel steering mode; the step of controlling the operation of the rear axle steering cylinder includes: controlling the switching of the three-position four-way valve between different working positions, and combining the hydraulic oil flow direction from the steering gear to realize the coordinated operation of the front and rear axles in the three modes of front wheel steering, all-wheel steering and crab steering.

[0012] In one embodiment, in the crab steering mode, the first end of the three-position four-way valve is energized, causing hydraulic oil from the steering gear to drive the rear axle steering cylinder to move in the same direction as the front axle steering cylinder via a specific oil circuit of the three-position four-way valve; in the all-wheel steering mode, the second end of the three-position four-way valve is energized, causing hydraulic oil from the steering gear to drive the rear axle steering cylinder to move in the opposite direction to the front axle steering cylinder via another specific oil circuit of the three-position four-way valve.

[0013] In one embodiment, the rear axle alignment correction operation is also used to periodically or in real time detect the centering state of the rear axle when the telescopic boom forklift is traveling or operating in any steering mode, and actively perform rear axle position correction when it is determined that the rear axle deviates from the alignment position due to hydraulic leakage or mechanical vibration, so as to maintain the stability of straight-line travel.

[0014] A semi-automatic steering control device for a telescopic boom forklift truck, the device comprising: The mode selection module is used to receive a target steering mode selection command issued by the operator. The steering modes include at least the front wheel steering mode, the all-wheel steering mode, and the crab steering mode, but do not include an independent rear wheel steering mode. The status detection module is used to obtain the current steering mode and the center position status of the rear axle; The control processing module is used to respond to the selection command, determine whether the current steering mode is consistent with the target steering mode, and if they are inconsistent, based on the preset control strategy, first switch the current steering mode to a transition mode that can drive the rear axle to actively steer, and generate a rear axle centering correction command; then switch the current steering mode to a front wheel mode that can drive the front axle to actively steer, and generate a front axle centering correction command. The drive execution module is configured to perform a rear axle alignment correction operation in the transition mode according to the instructions of the control processing module, and switch the transition mode to the front wheel steering mode after confirming that the rear axle has completed the alignment correction. After confirming that the front axle has completed the alignment correction, the system successfully switches to the target steering mode.

[0015] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program performing the following steps: Receive the target steering mode selection command issued by the operator; In response to the selection command, determine whether the current steering mode is consistent with the target steering mode; If there is a discrepancy, the current steering mode will be switched to a transition mode based on a preset control strategy, and a rear axle centering correction operation will be performed; wherein, the transition mode is one of an all-wheel steering mode or a crab steering mode that can drive the rear axle to actively steer. After confirming that the rear axle has completed the centering correction, the transition mode is switched to the front wheel steering mode; after confirming that the front axle has completed the centering correction, the target steering mode is successfully switched.

[0016] The rear axle alignment correction operation includes: obtaining the center position of the rear axle through a detection device, and controlling the rear axle steering cylinder to move based on the center position until the rear axle returns to the preset alignment position.

[0017] The front axle alignment correction operation includes: obtaining the center position of the front axle through a detection device, and controlling the front axle steering cylinder to move based on the center position until the front axle returns to the preset alignment position.

[0018] A computer-readable storage medium having a computer program stored thereon, the computer program performing the following steps when executed by a processor: Receive the target steering mode selection command issued by the operator; In response to the selection command, determine whether the current steering mode is consistent with the target steering mode; If there is a discrepancy, the current steering mode will be switched to a transition mode based on a preset control strategy, and a rear axle centering correction operation will be performed; wherein, the transition mode is one of an all-wheel steering mode or a crab steering mode that can drive the rear axle to actively steer. After confirming that the rear axle has completed the centering correction, the transition mode is switched to the front wheel steering mode; after confirming that the front axle has completed the centering correction, the target steering mode is successfully switched.

[0019] The rear axle alignment correction operation includes: obtaining the center position of the rear axle through a detection device, and controlling the rear axle steering cylinder to move based on the center position until the rear axle returns to the preset alignment position.

[0020] The front axle alignment correction operation includes: obtaining the center position of the front axle through a detection device, and controlling the front axle steering cylinder to move based on the center position until the front axle returns to the preset alignment position.

[0021] The aforementioned semi-automatic steering control method and device for telescopic boom forklifts fundamentally eliminates the possibility of accidental entry into the dangerous rear-wheel steering mode by pre-setting front-wheel steering, all-wheel steering, and crab steering modes in the control system, without setting a separate rear-wheel steering mode, thus improving the safety of vehicle driving and operation. Simultaneously, by introducing a transition mode and automatic rear axle centering correction, the traditional manual centering and switching process, which relies on operator experience, is transformed into a semi-automatic process controlled by the system. The operator only needs to issue a target mode command, and the system intelligently selects the transition mode and completes the centering correction based on the current state, ultimately achieving mode switching. This solution not only simplifies the operation process and improves the success rate and efficiency of mode switching, but also reduces system cost and failure rate by simplifying the hydraulic circuit and eliminating redundant valve groups and pipelines configured for the independent rear-wheel steering mode, thereby improving the overall reliability of the machine. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating a semi-automatic steering control method for a telescopic boom forklift in one embodiment. Figure 2 This is a hydraulic schematic diagram for another embodiment; Figure 3 This is a structural block diagram of a semi-automatic steering control device for a telescopic boom forklift in one embodiment. Figure 4 This is an internal structural diagram of a computer device in one embodiment; The attached diagram includes the following symbols: 1. First end of the three-position four-way valve; 2. Second end of the three-position four-way valve; 3. Three-position four-way valve; 4. Rear axle steering cylinder; 5. Front axle steering cylinder. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0024] The semi-automatic steering control method for telescopic boom forklifts provided in this application can be applied to the following environment: This environment includes an onboard control system installed on the telescopic boom forklift. The onboard control system integrates a display screen, a controller, an inductive proximity switch or laser beam switch for detecting the alignment of the front and rear axles, and a solenoid valve assembly for driving the steering cylinders. The operator issues a target steering mode selection command via the display screen or physical switch in the cab. Upon receiving the command, the controller determines whether the current mode matches the target mode according to preset program logic. If they do not match, it automatically executes a semi-automatic sequential switching process, including transition mode selection, rear axle alignment correction, and front axle correction. This solution allows the system to automatically complete complex mode switching processes with just a single operator click, greatly improving operational convenience and safety.

[0025] In one embodiment, such as Figure 1 As shown, a semi-automatic steering control method for telescopic boom forklifts is provided, with the application of this method to the on-board controller in the aforementioned application scenario as an example for illustration. This steering control system presets a front-wheel steering mode, an all-wheel steering mode, and a crab steering mode. Furthermore, this system and the corresponding method do not set, include, or support an independent rear-wheel steering mode. The method specifically includes the following: First, the system receives a target steering mode selection command from the operator. This command is issued by the operator through the user interface based on the current operational requirements, indicating the target mode the system should switch to.

[0026] Next, in response to the selection command, the system determines whether the current steering mode matches the target steering mode. If they match, the system does not need to perform a switching action and maintains the current mode.

[0027] If the judgment result is inconsistent, a semi-automatic switching process is initiated. This process first involves switching the current steering mode to a transition mode based on a preset control strategy, and simultaneously or subsequently performing a rear axle alignment correction operation. The transition mode is set to either all-wheel steering or crab steering. These two modes are the modes in this system that can drive the rear axle steering cylinder to actively move, and are necessary conditions for completing the rear axle position correction.

[0028] After the system confirms that the rear axle has completed the alignment correction operation, i.e., the rear axle has returned to the preset alignment position, the current transition mode is switched to the front wheel steering mode. The front wheel steering mode is the mode in this system that can drive the front axle steering cylinder to actively move, and is a necessary condition for completing the front axle position correction. After the system confirms that the front axle has completed the alignment correction operation, i.e., the front axle has returned to the preset alignment position, it finally switches to the target steering mode indicated by the initially received command.

[0029] The aforementioned rear axle alignment correction operation specifically includes: acquiring the real-time alignment status of the rear axle using a preset detection device, such as an inductive proximity switch or laser beam switch installed near the rear axle steering mechanism. Based on this alignment status signal, the controller determines whether the rear axle is in the aligned position. If not aligned, the controller generates a drive command to control the corresponding solenoid valve, such as the solenoid valve controlling the rear axle steering cylinder, driving the rear axle steering cylinder to extend or retract until the signal from the detection device indicates that the rear axle has accurately returned to the preset alignment position.

[0030] The aforementioned front axle alignment correction operation specifically includes: acquiring the real-time centering status of the front axle using a preset detection device, such as an inductive proximity switch or laser beam switch installed near the front axle steering mechanism. Based on this centering status signal, the controller determines whether the front axle is in the aligned position. If not aligned, the controller generates a drive command to control the corresponding solenoid valve, such as the solenoid valve controlling the front axle steering cylinder, driving the front axle steering cylinder to extend or retract until a signal from the detection device indicates that the front axle has accurately returned to the preset centering position.

[0031] The core of the method described in this embodiment lies in transforming the decision-making and execution process of mode switching from manual operation to semi-automatic system control. Operators no longer need to manually find the alignment position and determine the switching timing; they only need to issue the target command, and the system will automatically utilize the modes capable of driving the rear and front axles as transitions, first completing the necessary alignment correction before switching to the target mode. This method effectively solves the problems of low efficiency and high failure rate of traditional manual switching methods. Simultaneously, since the system architecture does not have a separate rear-wheel steering mode, it completely avoids the safety risks such as rollovers caused by accidental entry into this dangerous mode. The entire solution improves operational convenience while ensuring operational safety.

[0032] In one embodiment, the specific method for selecting the transition mode based on a preset control strategy is defined. When the system determines that the current steering mode is the front-wheel steering mode, and the operator issues a target steering mode selection command of all-wheel steering mode or crab steering mode, the system's control strategy is as follows: directly select the target steering mode as the transition mode, perform a rear axle alignment correction operation in this mode, select the front-wheel steering mode again after the correction is completed, perform a front axle alignment correction operation, and then formally enter the target mode.

[0033] In one embodiment, a transition mode selection strategy is defined for another mode switching scenario. When the system determines that the current steering mode is all-wheel steering and the target steering mode is crab steering; or, the current steering mode is crab steering and the target steering mode is all-wheel steering, the system's control strategy is: select the current steering mode as the transition mode. That is, maintain the current mode unchanged, first perform rear axle alignment correction operation in this mode, and after the rear axle alignment is completed, switch the mode from the current transition mode to the front wheel steering mode. After the front axle alignment is completed, switch to the target steering mode.

[0034] This embodiment demonstrates the switching between steering modes. It avoids rear axle centering deviation caused by hydraulic cylinder leakage or mechanical vibration, which could affect driving stability and safety. Therefore, the control strategy prioritizes ensuring the rear axle completes centering correction in the selected transition mode before switching to the front wheel mode to complete front axle centering correction. This ensures the basic switching state is standard and controllable, guaranteeing safety and stability under complex switching paths.

[0035] In one embodiment, the transition mode selection strategy has been further improved and supplemented. When a mode switch is required, the system not only considers the current steering mode but also acquires the current steering wheel angle position information or the steering angle information of the front and rear axles through the front and rear axle angle sensors. When the system detects that the steering wheel is not in the center position, i.e., the driver is performing a steering operation, or the steering angle of the front and rear axles has not yet returned to center, the system intelligently selects a suitable transition mode based on the acquired steering wheel position or steering angle information. The selection principle is to ensure that the initial position, force state, and motion trend of the rear axle are conducive to moving towards the center position before performing subsequent centering correction operations, i.e., to pre-establish a trend towards the center position or shorten its path back to the center position.

[0036] This embodiment considers dynamic scenarios where the switching operation occurs during steering. For example, in all-wheel mode, when the steering wheel is turned all the way to the left, the rear axle deflects to its extreme right. If switching to crab mode is required at this point, an improperly selected transition mode could lead to unreasonable stress on the rear axle hydraulic system or an inability to effectively correct it. By introducing steering wheel or steering angle signals as the basis for selecting the transition mode, centering difficulties or mechanical shocks caused by improper transition mode selection under extreme conditions can be avoided, thus improving the robustness and intelligence of the control strategy.

[0037] In one embodiment, the hardware architecture, particularly the hydraulic circuit, upon which this control method relies is described in detail. The steering control system in this embodiment features a simplified hydraulic circuit design, containing only a single three-position four-way valve for switching between all-wheel steering and crab steering modes. Crucially, this hydraulic circuit eliminates the two-position four-way valve typically found in conventional designs, which is used to lock the front wheels to create an independent rear-wheel steering mode. This simplified hydraulic circuit design eliminates the possibility of achieving an independent rear-wheel steering mode at the physical hardware level, fundamentally preventing the risk of accidentally entering a dangerous rear-wheel steering mode due to electronic control system malfunction or misoperation.

[0038] Based on this hardware, the specific steps for controlling the rear axle steering cylinder include: the controller outputs an electrical signal to control the three-position four-way valve to switch between different working positions, while simultaneously receiving hydraulic oil from the steering gear. By changing the position of the valve core, the hydraulic oil is guided to different oil circuits, thereby driving the rear axle steering cylinder to extend and retract in different directions. This works in conjunction with the linkage of the front axle steering cylinder to ultimately achieve three modes: front wheel steering, all-wheel steering, and crab steering.

[0039] The beneficial effect of this embodiment is that it not only describes a control method but also clarifies the optimal hardware architecture to support the method. The simplified hydraulic circuit reduces the number of hydraulic components, directly resulting in multiple beneficial effects such as cost reduction, simplified assembly, fewer points of failure, and improved system reliability. It is an organic combination of method invention and hardware structure improvement.

[0040] In one embodiment, based on the simplified hydraulic circuit of the previous embodiment, the specific hydraulic circuit operation process in both all-wheel and crab-like modes is described in detail. For example... Figure 2 As shown, in crab steering mode, the controller controls the first terminal 1 of the three-position four-way valve, for example, terminal a is energized and terminal b is de-energized. At this time, when the steering wheel is turned, the hydraulic oil from the steering gear is guided to the rear axle steering cylinder 4 and the front axle steering cylinder 5 respectively through the specific oil circuit of the three-position four-way valve 3, namely the passage from port P to port A and port B to port T, so that the piston rods of the two cylinders move in the same direction, thereby driving the front and rear axle wheels to deflect in the same direction and completing the crab steering action.

[0041] In all-wheel steering mode, the controller controls the second terminal 2 of the three-position four-way valve, for example, energizing terminal b and de-energizing terminal a. At this time, the hydraulic oil from the steering gear is guided to the rear axle steering cylinder 4 and the front axle steering cylinder 5 respectively through another specific oil circuit of the three-position four-way valve 3, namely the passage from port P to port B and port A to port T (or vice versa), so that the piston rods of the two cylinders move in opposite directions, thereby driving the front and rear axle wheels to turn in opposite directions and completing the all-wheel steering action.

[0042] In front-wheel steering mode, both ends a and b of the three-position four-way valve 3 are de-energized or in the neutral position. Hydraulic oil from the steering gear flows only to the front axle steering cylinder 5, and the oil circuit of the rear axle steering cylinder 4 is blocked, so only the front wheels perform steering.

[0043] This embodiment, by detailing the hydraulic circuit conduction logic of a three-position four-way valve under different energized states, clearly and completely explains how to achieve three completely different steering functions using the simplest combination of hydraulic components. This fully demonstrates that the technical solution of this application achieves functional completeness while realizing the design goal of structural simplification, reflecting the advanced nature of the technology.

[0044] In one embodiment, the functionality of the rear axle alignment correction operation is extended. This operation not only occurs during the aforementioned mode switching process, but can also be periodically or in real-time triggered by the system when the telescopic boom forklift is driving or operating normally in any steering mode (including front wheel, all-wheel, and crab mode). Specifically, the system continuously monitors the centering status of the rear axle through a detection device. When, during non-switching processes, the system determines that the rear axle has deviated from the preset alignment position due to minor internal leakage caused by long-term pressure or vibration of the hydraulic system, or due to mechanical vibration under harsh working conditions, the system will proactively prompt for rear axle alignment correction operation.

[0045] The effect of this embodiment is that it reveals another important function of the rear axle alignment correction operation—maintaining straight-line stability. This function solves the problem of vehicle deviation caused by the characteristics of hydraulic components or external environmental influences after long-term operation of construction machinery. It is equivalent to a permanent automatic calibration function, continuously ensuring the directional stability and safety of the vehicle during straight-line driving, especially during high-speed transfers.

[0046] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0047] In one embodiment, such as Figure 3 As shown, a semi-automatic steering control device for a telescopic boom forklift truck includes: a mode selection module, a status detection module, a control processing module, and a drive execution module.

[0048] The mode selection module receives a target steering mode selection command from the operator via a human-machine interface, such as a display screen or physical switch. The device supports at least front-wheel steering, all-wheel steering, and crab steering modes, and its architecture and functional definition do not include an independent rear-wheel steering mode.

[0049] The status detection module is used to acquire the current steering mode and the real-time neutral position status of the rear axle of the telescopic boom forklift. The current steering mode can be obtained by reading the status flag bit inside the controller, while the neutral position status of the rear axle is obtained by receiving signals from detection devices such as inductive proximity switches or laser beam switches.

[0050] The control processing module is the core logic processing unit of the device. It responds to selection commands received by the mode selection module by first determining whether the current steering mode matches the target steering mode. If they do not match, it generates a mode switching sequence command based on a preset control strategy. Specifically, it first switches the current steering mode to a transitional mode capable of driving the rear axle to actively steer, and synchronously or asynchronously generates a rear axle alignment correction command. After completion, it switches the current steering mode to a transitional mode capable of driving the front axle to actively steer, and synchronously or asynchronously generates a front axle alignment correction command.

[0051] The drive execution module receives and executes commands from the control processing module. Based on these commands, in transition mode, it controls the corresponding solenoid valves to drive the rear axle steering cylinder to perform rear axle alignment correction. After the status detection module confirms that the rear axle has completed alignment correction, the drive execution module further executes commands to switch the current transition mode to front-wheel steering mode, driving the front axle steering cylinder to perform front axle alignment correction. After the status detection module confirms that the front axle has completed alignment correction, it finally switches to the target steering mode.

[0052] In one embodiment, the control processing module is further configured to, when determining that the current steering mode is the front wheel steering mode and the target steering mode is the all-wheel steering mode or the crab steering mode, first select the target steering mode as the transition mode, generate a rear axle centering correction command and receive correction feedback, then switch to the front wheel steering mode, generate a front axle centering correction command and receive correction feedback, and then generate a target mode switching success command.

[0053] In one embodiment, the control processing module is further configured to select the current steering mode as a transition mode when it is determined that the current steering mode is an all-wheel steering mode and the target steering mode is a crab steering mode, or when the current steering mode is a crab steering mode and the target steering mode is an all-wheel steering mode, and after generating a rear axle alignment correction command and receiving correction completion feedback, switch to the front wheel steering mode, generate a front axle alignment correction command and receive correction feedback, and generate a target mode switching success command.

[0054] In one embodiment, the state detection module is further configured to acquire the current steering wheel angle position information or the steering angle information of the front and rear axles. The control processing module is further configured to select the corresponding transition mode based on the acquired angle information when the steering wheel is in a non-neutral state or the steering angle of the front and rear axles has not returned to center.

[0055] In one embodiment, the hydraulic circuit controlled by the drive actuator module includes only a three-position four-way valve for switching between all-wheel steering and crab steering modes, and does not include a two-position four-way valve for locking the front wheels. The drive actuator module controls the switching of this three-position four-way valve between different operating positions, and combines this with the hydraulic oil flow direction from the steering gear to achieve the three steering modes.

[0056] In one embodiment, the state detection module is further configured to periodically or in real-time detect the centering state of the rear axle when the device is in any steering mode. The control processing module is further configured to actively generate a rear axle centering correction command when it is determined that the rear axle is deviating from the centering position, and hand it over to the drive execution module for execution, so as to maintain the stability of the vehicle's straight-line driving.

[0057] Specific limitations regarding the semi-automatic steering control device for telescopic boom forklifts can be found in the above description of the semi-automatic steering control method for telescopic boom forklifts, and will not be repeated here. Each module in the aforementioned semi-automatic steering control device for telescopic boom forklifts can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0058] In one embodiment, a computer device is provided, which may be an on-board controller mounted on a telescopic boom forklift. Its internal structure diagram can be as follows: Figure 4As shown, the computer device includes a processor, memory, network interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface is used to communicate with external terminals via a network connection, for example, for program updates or data downloads. When executed by the processor, the computer program implements a semi-automatic steering control method for a telescopic boom forklift. The display screen can be an LCD screen, used to display information such as the current steering mode, target steering mode, and switching status prompts. The input devices can be a touch layer covering the display screen or physical buttons on the device casing, used to receive mode selection commands from the operator.

[0059] Those skilled in the art will understand that Figure 4 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0060] In one embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps of the method described above.

[0061] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described above.

[0062] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0063] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0064] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A semi-automatic steering control method for telescopic boom forklifts, characterized in that, The method is applied to a steering control system, which presets multiple steering modes, including at least a front-wheel steering mode, an all-wheel steering mode, and a crab steering mode, but does not set a separate rear-wheel steering mode; the method includes: Receive the target steering mode selection command issued by the operator; In response to the selection command, determine whether the current steering mode is consistent with the target steering mode; If there is a discrepancy, the current steering mode will be switched to a transition mode based on a preset control strategy, and a rear axle centering correction operation will be performed; wherein, the transition mode is one of an all-wheel steering mode or a crab steering mode that can drive the rear axle to actively steer. After confirming that the rear axle has completed the centering correction, the transition mode is switched to the front wheel steering mode; after confirming that the front axle has completed the centering correction, the target steering mode is successfully switched. The rear axle alignment correction operation includes: obtaining the center position state of the rear axle through a detection device, and controlling the rear axle steering cylinder to move based on the center position state until the rear axle returns to the preset alignment position. The front axle alignment correction operation includes: obtaining the center position state of the front axle through a detection device, and controlling the front axle steering cylinder to move based on the center position state until the front axle returns to the preset alignment position.

2. The semi-automatic steering control method for a telescopic boom forklift according to claim 1, characterized in that, The step of switching the current steering mode to a transition mode based on a preset control strategy includes: When the current steering mode is front-wheel steering mode and the target steering mode is all-wheel steering mode or crab steering mode, the target steering mode is selected as the transition mode, and a rear axle centering correction operation is performed.

3. The semi-automatic steering control method for telescopic boom forklifts according to claim 1, characterized in that, The step of switching the current steering mode to a transition mode based on a preset control strategy specifically includes: When the current steering mode is all-wheel steering mode and the target steering mode is crab steering mode, or when the current steering mode is crab steering mode and the target steering mode is all-wheel steering mode, the current steering mode is selected as the transition mode, and after performing the rear axle centering correction operation, the transition mode is switched to the front wheel steering mode. After performing the front axle centering correction operation, the mode is automatically switched to the target steering mode.

4. The semi-automatic steering control method for telescopic boom forklifts according to claim 1, characterized in that, The step of switching the current steering mode to the transition mode based on a preset control strategy further includes: Obtain the current steering wheel position or the steering angle information of the front and rear axles; When the steering wheel is not in the center position or the steering angle of the front and rear axles has not returned to center, the corresponding transition mode is selected according to the steering angle information or steering position information, so that the rear axle has a tendency or path to move towards the center position before performing centering correction.

5. The semi-automatic steering control method for a telescopic boom forklift according to claim 1, characterized in that, The hydraulic circuit of the steering control system contains only one three-position four-way valve for switching between the all-wheel steering mode and the crab steering mode, and does not contain a two-position four-way valve for locking the front wheels to form an independent rear-wheel steering mode. The steps for controlling the rear axle steering cylinder include: controlling the switching of the three-position four-way valve between different working positions, and combining the hydraulic oil flow direction from the steering gear to achieve coordinated front and rear axle movements in three modes: front wheel steering, all-wheel steering, and crab steering.

6. The semi-automatic steering control method for a telescopic boom forklift according to claim 5, characterized in that, In the crab steering mode, the first end of the three-position four-way valve is energized, causing the hydraulic oil from the steering gear to drive the rear axle steering cylinder to move in the same direction as the front axle steering cylinder through the specific oil circuit of the three-position four-way valve. In the all-wheel steering mode, the second end of the three-position four-way valve is energized, causing the hydraulic oil from the steering gear to drive the rear axle steering cylinder to move in the opposite direction to the front axle steering cylinder via another specific oil circuit of the three-position four-way valve.

7. The semi-automatic steering control method for a telescopic boom forklift according to claim 1, characterized in that, The rear axle alignment correction operation is also used to periodically or in real time detect the centering status of the rear axle when the telescopic boom forklift is traveling or operating in any steering mode, and actively perform rear axle position correction when it is determined that the rear axle deviates from the alignment position due to hydraulic leakage or mechanical vibration, so as to maintain the stability of straight-line travel.

8. A semi-automatic steering control device for a telescopic boom forklift, characterized in that, The device includes: The mode selection module is used to receive the target steering mode selection command issued by the operator. The steering modes include at least the front wheel steering mode, the all-wheel steering mode, and the crab steering mode, but do not include the independent rear wheel steering mode. The status detection module is used to obtain the current steering mode and the center position status of the rear axle; The control processing module is used to respond to the selection command, determine whether the current steering mode is consistent with the target steering mode, and if they are inconsistent, switch the current steering mode to a transition mode that can drive the rear axle to actively steer based on a preset control strategy, and generate a rear axle centering correction command. The drive execution module is used to perform rear axle and front axle alignment correction operations in the transition mode according to the instructions of the control processing module, and switch the transition mode to the target steering mode after confirming that the rear axle and front axle have completed the alignment correction.

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