A control method for reducing sway of a forward-moving forklift mast

Abstract

The application provides a control method for reducing the swing of a front-moving forklift mast, and belongs to the technical field of front-moving forklift control. The method comprises the following steps: after detecting that the front-moving forklift is in a parking state, the action type of the mast is acquired; if the action type of the mast is a lifting action, the electromagnetic clutch is controlled to be opened, the transmission system is controlled to be in a non-locking state, and the driving motor is controlled to output a reverse electromagnetic torque to absorb the impact load generated by the swing of the mast; if the action type of the mast is a front-back movement action, the electromagnetic clutch is controlled to be closed to limit the front-back movement of the vehicle body. The method provided by the application can reduce the swing of the mast and ensure the stability and reliability in different working scenarios by implementing differentiated control according to different mast actions.

Description

Technical Field

[0001] This application relates to the field of reach truck control technology, and in particular to a control method for reducing mast sway in a reach truck. Background Technology

[0002] Reach trucks are commonly used industrial vehicles in warehousing, logistics, and production handling scenarios, capable of lifting, transporting, stacking, and retrieving goods. The mast, as a crucial actuator of the reach truck, directly affects the stability of the forks and goods, further influencing the forklift's operational accuracy, efficiency, and safety. Especially under conditions of full load, lifting, and stacking, the mast is prone to varying degrees of swaying during operation, thus affecting the forklift's smooth operation. Therefore, improving the stability of the reach truck mast during operation has always been a key technical issue in this field.

[0003] In related technologies, to improve the stability of reach trucks during operation, optimizations are typically made in mechanical structure design, hydraulic system adjustment, vehicle control strategies, or braking and holding methods. For example, improving the rigidity of the mast and body structure, optimizing the control parameters of hydraulic actuators, and braking or locking the vehicle when it is stopped can reduce displacement or vibration during operation. However, these methods still have certain limitations in practical applications: on the one hand, during mast lifting or lowering, the inertia of the mast and cargo, the clearance of the vehicle's drivetrain, and changes in ground conditions combine to easily lead to prolonged mast swaying, affecting high-level operation efficiency; on the other hand, different mast movements have different requirements for overall vehicle stability. For example, during mast lifting, the focus is on suppressing swaying impact, while during mast forward and backward movement, the focus is on limiting the forward and backward movement of the vehicle body. Existing technologies usually cannot implement differentiated control for different operating conditions, thus making it difficult to balance operational stability and overall vehicle reliability.

[0004] Therefore, in the mast control of reach trucks, the difficulty in effectively suppressing mast swaying and the challenge in balancing stability and reliability under different operating scenarios have become urgent problems to be solved. Summary of the Invention

[0005] This application provides a control method to reduce mast sway in reach trucks, aiming to solve the technical problems of mast sway not being effectively suppressed in existing reach truck mast control, and the difficulty in balancing stability and reliability under different operating scenarios.

[0006] In a first aspect, this application provides a control method for reducing mast sway in a reach truck, applied to a reach truck including an electromagnetic clutch, a drive motor, and a motor controller, characterized in that the method includes: After detecting that the reach truck is in a stopped state, the action type of the mast is obtained; If the action type of the gantry is lifting action, control the electromagnetic clutch to open, so that the transmission system is in an unlocked state, and control the drive motor to output reverse electromagnetic resistance torque to absorb the impact load generated by the gantry swaying; If the mast's movement is a forward or backward movement, the electromagnetic clutch is controlled to close to limit the vehicle's forward or backward movement.

[0007] In one possible design, prior to obtaining the action type of the gantry, the method further includes: After the reach truck system is powered on, it is checked whether there is a manual release of the parking gear. If there is no manual disengagement of the parking gear, the electromagnetic clutch remains closed; If a manual release of the parking position is performed, check whether the reach truck is in a parked state. If the reach truck is not stopped, control the electromagnetic clutch to open.

[0008] In one possible design, after obtaining the action type of the gantry, the method further includes: If the gantry is not in motion, the electromagnetic clutch is controlled based on the on / off state of the parking gear.

[0009] In one possible design, the condition for determining that the reach truck is in a stopped state is: the vehicle speed of the reach truck is lower than a preset speed threshold, and the state of the vehicle speed being lower than the preset speed threshold continues for a first preset duration.

[0010] In one possible design, when the gantry's action type is lifting and the electromagnetic clutch is engaged, the impact load generated by the gantry's swaying is transmitted to the drive motor, and the drive motor adaptively adjusts the reverse electromagnetic resistance torque according to the magnitude of the impact load.

[0011] In one possible design, after controlling the drive motor to output a reverse electromagnetic resistance torque, the method further includes: Obtain the operating environment information of the reach truck; Based on the operating environment information, the parameters of the reverse electromagnetic resistance torque are adjusted so that the adjusted reverse electromagnetic resistance torque is used to suppress mast sway under flat conditions, and the upper limit value under slope conditions is less than the parking braking torque of the reach truck.

[0012] In one possible design, adjusting the parameters of the reverse electromagnetic drag torque based on the operating environment information includes: Based on the operating environment information, the output current and / or magnetic field strength of the drive motor controller are adjusted to regulate the magnitude of the reverse electromagnetic resistance torque.

[0013] In one possible design, the working environment information includes tilt information acquired via a tilt sensor; The step of adjusting the parameters of the reverse electromagnetic drag torque based on the operating environment information includes: Based on the ramp coefficient corresponding to the tilt angle information and the preset correlation, the upper limit of the reverse electromagnetic resistance torque is adaptively adjusted; wherein, the preset correlation is used to indicate the correspondence between the ramp coefficient and the reverse electromagnetic resistance torque parameter; the preset correlation is a linear function relationship, and the slope and intercept of the linear function relationship are obtained by bench testing of the reach truck under no-load and full-load conditions.

[0014] In one possible design, when the reach truck is not equipped with a tilt sensor, controlling the drive motor to output a reverse electromagnetic resistance torque includes: The drive motor is controlled to first output a first reverse electromagnetic resistance torque, and then switch to a second reverse electromagnetic resistance torque after a second preset time period, wherein the second reverse electromagnetic resistance torque is less than the first reverse electromagnetic resistance torque.

[0015] In one possible design, the method further includes: When the reach truck is on a ramp, a prompt message is output, which prompts the operator to perform an active parking operation. The prompts include text prompts on the vehicle display screen, icon prompts on the display screen, and / or audible and visual alarms from a buzzer. The active parking operation includes parking by at least one of the following: electromagnetic clutch locking, hydraulic braking, and mechanical braking.

[0016] Secondly, this application provides a control device for reducing mast sway of a reach truck, comprising: a module for performing the aforementioned method embodiment of the first aspect.

[0017] Thirdly, this application provides a control device for reducing mast sway of a reach truck, comprising: a memory and at least one processor; The memory stores computer-executed instructions; The at least one processor executes computer execution instructions stored in the memory, causing the at least one processor to perform the method described in the first aspect or various possible designs of the first aspect.

[0018] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed, implement the method described in the first aspect or various possible designs of the first aspect.

[0019] Fifthly, this application provides a computer program product, which includes computer program code that, when run on a computer, causes the computer to implement the method described in the first aspect or various possible designs of the first aspect.

[0020] This application provides a control method for mitigating mast sway in a reach truck. After detecting that the reach truck is in a stopped state, the method first obtains the mast's motion type and then implements differentiated control for different motion types. When the mast's motion type is lifting, the electromagnetic clutch is opened, putting the transmission system in an unlocked state. The drive motor is then controlled to output a reverse electromagnetic resistance torque. This ensures that the impact load generated by mast sway is no longer primarily borne by the mechanical locking structure under the closed electromagnetic clutch state, but is instead transmitted through the transmission system to the drive motor and absorbed and offset by the reverse electromagnetic resistance torque. This reduces the amplitude and duration of mast sway during lifting, thereby improving the effectiveness of mast sway suppression in related technologies. This invention addresses the issue of control; simultaneously, when the mast's movement is forward or backward, the electromagnetic clutch is closed to constrain the vehicle body, thereby limiting the forward or backward movement of the vehicle body during the mast's forward or backward movement. Since this application does not use the same clutch control method for all mast movements, but adopts different control strategies according to the differences in stability requirements between lifting and forward / backward movements, it can focus on suppressing swaying and impact in mast lifting scenarios and on limiting vehicle body displacement in mast forward / backward movement scenarios, thus taking into account both stability and reliability in different operating scenarios. This solves the technical problems of difficulty in effectively suppressing mast swaying and the difficulty in balancing stability and reliability in different operating scenarios in existing reach truck mast control systems. Attached Figure Description

[0021] Figure 1 A flowchart illustrating a control method for reducing mast sway in a reach truck provided in this application embodiment; Figure 2 A flowchart illustrating another control method for reducing mast sway in a reach truck provided in this application embodiment; Figure 3 A flowchart illustrating another control method for reducing mast sway in a reach truck provided in this application embodiment; Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims and drawings of this application are intended to cover non-exclusive inclusion.

[0024] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] In this article, the term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists, A and B can exist simultaneously, and B exists. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0026] Furthermore, the terms "first," "second," etc., in the specification and claims of this application or in the aforementioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0027] In the description of this application, unless otherwise stated, "multiple" and "at least two" mean two or more (including two), and similarly, "multiple groups" and "at least two groups" mean two or more (including two groups).

[0028] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, "connected" or "linked" can refer not only to a physical connection, but also to an electrical connection or a signal connection. For instance, it can be a direct connection, i.e., a physical connection, or an indirect connection through at least one intermediate component, as long as the circuit is connected. It can also refer to the internal connection between two components. A signal connection can refer not only to a signal connection through a circuit, but also to a signal connection through a medium, such as radio waves. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0029] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, different technical features in this application can be combined with each other.

[0030] Reach trucks are commonly used equipment in warehousing and logistics operations. Mast lifting is a crucial operational action. In scenarios involving full loads and high-level stacking, the mast is prone to significant swaying, which not only reduces operational accuracy but also increases waiting time, impacting overall operational efficiency. A proposed technology involves a stable parking brake method based on a proportional service brake. Its control logic is as follows: when the forklift is parked and the parking brake is engaged, the rear wheel electromagnetic clutch is closed; when the forks are lifting, the front wheel clutch is simultaneously closed; when there is no lifting, the front wheel clutch is opened. This method attempts to reduce mast sway by locking the front and rear wheel electromagnetic clutches.

[0031] The electromagnetic clutch used in this technology is usually a brake pad structure, with a certain gap between the brake pads. In the de-energized state, the conical spring separates the brake pads, and in the energized state, the coil generates a magnetic field to attract the brake pads and achieve clutch locking. However, this control method still has certain limitations in practical applications: First, clutch locking mainly restricts vehicle displacement through mechanical locking, which is difficult to effectively absorb the impact load generated by mast swaying. Moreover, the brake pads are non-rigid connections that are magnetically pressed together. When combined with the gear clearance of the rear-wheel drive gearbox, the swaying impact force can easily drive the brake pads to vibrate and rub continuously, accelerating the wear of the brake pads and transmission components and affecting the service life of the equipment. Second, in high-level stacking scenarios, the superposition effect of brake pad vibration and friction and gear clearance may further amplify the swaying amplitude of the forks and goods. Operators usually need to wait for the swaying to end before they can carry out subsequent operations, thereby reducing work efficiency. Third, the relevant technology does not design differentiated control logic for different mast movements, making it difficult to meet the dual operational requirements of sway suppression and vehicle anti-rollover. Fourth, the relevant technology does not fully consider the differences in forklift operation on flat ground and slopes. If resistance is increased simply through mechanical structure or control methods, it is easy to create a parking illusion on slopes, which may lead to increased equipment energy consumption and aggravated heat generation of core components, resulting in certain operational safety hazards.

[0032] Based on the above, this application proposes a control method to reduce mast sway of reach trucks, so as to effectively suppress mast sway and reduce component wear during mast lifting operations, while taking into account the stability requirements under different operating scenarios.

[0033] Figure 1 This is a flowchart illustrating a control method for reducing mast sway in a reach truck, as provided in an embodiment of this application. Figure 1 As shown, the control method provided in this application embodiment specifically includes S101 to S103, and S101 to S103 will be described in detail below.

[0034] It should be noted that the control method for reducing mast sway of a reach truck provided in this application embodiment can be executed by a controller in the reach truck, and the controller can be a motor controller.

[0035] S101. After detecting that the reach truck is in a stopped state, obtain the action type of the mast.

[0036] The parking state can be understood as the state in which the reach truck is not in normal operating condition and the vehicle body does not move or shift.

[0037] In some implementations, the parking status can be determined by the controller based on vehicle operating parameters, such as vehicle speed, drive wheel speed, driving command status, braking status, or a combination thereof.

[0038] The types of gantry movements include at least lifting and lowering movements and forward and backward movement.

[0039] It should be noted that the lifting action can include the fork raising action and the fork lowering action; the forward and backward movement action can include the forward and backward movement of the mast or forks relative to the vehicle body.

[0040] The controller can identify the current action type of the gantry based on the control signal of the gantry actuator, the working status of the hydraulic system, the information of the gantry position sensor, the input signal of the control handle, or a combination thereof.

[0041] In this embodiment, by acquiring the mast's motion type while the vehicle is parked, different operating conditions of the mast can be mapped to different control strategies. Since the main problem encountered during mast lifting is the swaying and impact caused by the inertia of the mast and cargo, and the main problem encountered during mast forward and backward movement is the forward and backward movement of the vehicle body, it is necessary to first distinguish the mast's motion and then implement differentiated control for different motion types to improve the stability and operational reliability of the reach truck in parked operation scenarios.

[0042] S102. If the action type of the gantry is lifting, control the electromagnetic clutch to open, so that the transmission system is in an unlocked state, and control the drive motor to output the reverse electromagnetic resistance torque to absorb the impact load generated by the gantry swaying.

[0043] In this embodiment, when the controller detects that the mast's movement is a lifting action, it controls the electromagnetic clutch to open. After the electromagnetic clutch opens, the reach truck's transmission system switches from a locked state to an unlocked state, and the transmission system is in a relatively relaxed mechanical connection state. At this time, the swaying impact generated by the mast during lifting is no longer mainly borne directly by the clutch locking structure, but can be transmitted to the drive motor along the transmission chain.

[0044] With the transmission system in an unlocked state, the controller further controls the drive motor to output a reverse electromagnetic resistance torque. This reverse electromagnetic resistance torque is an electromagnetic resistance output opposite to the impact direction caused by gantry swaying, used to absorb and reduce the impact load generated by gantry swaying. In other words, during gantry lifting, when the gantry and cargo tend to sway due to inertia, transmission chain backlash, or structural elasticity, the drive motor outputs a reverse electromagnetic resistance torque to counteract the swaying impact, thereby reducing the frequency and amplitude of gantry vibration.

[0045] Unlike related technologies that mechanically lock the vehicle body by closing the electromagnetic clutch, this application does not simply rely on clutch lock-up to limit displacement. Instead, it actively opens the electromagnetic clutch during gantry lifting, freeing the transmission system from a rigid locking state. The reverse electromagnetic resistance torque output by the drive motor absorbs the impact of gantry swaying. This method reduces gantry swaying while decreasing the direct impact load on the clutch friction components and transmission clearances, thereby reducing wear on related parts and improving operational stability in scenarios such as high-level stacking.

[0046] S103. If the mast's movement type is forward and backward movement, control the electromagnetic clutch to close in order to limit the forward and backward movement of the vehicle body.

[0047] In this embodiment, when the controller detects that the gantry's movement is a forward / backward movement, it controls the electromagnetic clutch to close. After the electromagnetic clutch closes, the transmission system is locked, thereby constraining the forward / backward displacement of the vehicle body. Since the forward / backward movement of the gantry causes changes in the vehicle's center of gravity and inertia transmission, if the vehicle body displacement is not limited, the vehicle body may easily lurch forward / backward, affecting the positioning accuracy and operational stability of the gantry's forward / backward movement. Therefore, in forward / backward movement scenarios, using a closed electromagnetic clutch can more effectively suppress the forward / backward movement of the vehicle body.

[0048] This application does not employ a single, fixed clutch control method. Instead, it uses different control strategies depending on the type of mast movement: for lifting operations, the focus is on reducing mast swaying impact, so an open electromagnetic clutch with a reverse electromagnetic resistance torque is used; for forward and backward movements, the focus is on limiting the vehicle's forward and backward movement, so a closed electromagnetic clutch is used. This differentiated control allows the reach truck to achieve more suitable control effects in different parking scenarios, thus balancing the needs for mast sway suppression and vehicle displacement limitation.

[0049] This application provides a control method for mitigating mast sway in a reach truck. After detecting that the reach truck is in a stopped state, the method first obtains the mast's motion type and then implements differentiated control for different motion types. When the mast's motion type is lifting, the electromagnetic clutch is opened, putting the transmission system in an unlocked state. The drive motor is then controlled to output a reverse electromagnetic resistance torque. This ensures that the impact load generated by mast sway is no longer primarily borne by the mechanical locking structure under the closed electromagnetic clutch state, but is instead transmitted through the transmission system to the drive motor and absorbed and offset by the reverse electromagnetic resistance torque. This reduces the amplitude and duration of mast sway during lifting, thereby improving the effectiveness of mast sway suppression in related technologies. This invention addresses the issue of control; simultaneously, when the mast's movement is forward or backward, the electromagnetic clutch is closed to constrain the vehicle body, thereby limiting the forward or backward movement of the vehicle body during the mast's forward or backward movement. Since this application does not use the same clutch control method for all mast movements, but adopts different control strategies according to the differences in stability requirements between lifting and forward / backward movements, it can focus on suppressing swaying and impact in mast lifting scenarios and on limiting vehicle body displacement in mast forward / backward movement scenarios, thus taking into account both stability and reliability in different operating scenarios. This solves the technical problems of difficulty in effectively suppressing mast swaying and the difficulty in balancing stability and reliability in different operating scenarios in existing reach truck mast control systems.

[0050] Figure 2 This is a flowchart illustrating another control method for reducing mast sway in a reach truck, provided in an embodiment of this application. Figure 2 As shown, in one possible embodiment, before the method step shown in S101, the method further includes S201 to S204, which are described in detail below.

[0051] S201. After the reach truck system is powered on, check if there is any manual release of the parking gear.

[0052] The Parking (P) gear is used to keep the reach forklift in a parked state. Only after the operator issues a command to release the Parking gear via the corresponding control mechanism can the reach forklift enter the subsequent state judgment and motion control process.

[0053] Specifically, the controller can determine whether there is a manual disengagement of the parking gear by reading the parking gear switch signal, gear shift signal, control handle signal, control panel input signal, or a combination thereof.

[0054] By setting this detection step, the reach truck can prioritize confirming whether the operator has the subjective intention to release the parking restriction in the initial stage after the system is powered on. This avoids directly entering the subsequent action recognition and control process without releasing the parking position, ensuring the orderliness of the control logic and the safety of the vehicle's initial state.

[0055] If a manual release of the parking gear is detected, the controller executes the method steps shown in S203; if no manual release of the parking gear is detected, the controller executes the method steps shown in S202.

[0056] S202. Keep the electromagnetic clutch closed.

[0057] In this embodiment, if the controller detects that there is no manual release of the parking gear, it keeps the electromagnetic clutch in the closed state. At this time, the reach truck is still in the initial parking hold state, and the transmission system remains locked, which helps to prevent the reach truck from undergoing unexpected displacement due to external disturbances, accidental operation, or component gaps after the system is powered on.

[0058] In this embodiment, the electromagnetic clutch is not immediately changed unless the operator explicitly releases the parking position. Instead, it remains engaged, ensuring the reach truck remains in a relatively stable parking state. This improves the overall stability and safety of the reach truck during the initial power-on phase and provides clear starting conditions for subsequent state transitions.

[0059] S203. Check if the reach truck is in a stopped state.

[0060] In this embodiment, if the controller detects a manual release of the parking position, it further determines whether the reach truck is currently in a parked state.

[0061] It should be noted that the operator releasing the parking gear does not necessarily mean that the reach truck is in motion; it may still be stationary or in a waiting state. Therefore, it is necessary to continue to perform parking status detection after releasing the parking gear.

[0062] Specifically, the controller can determine whether the reach truck is in a stopped state based on vehicle speed, drive wheel speed, speed feedback signal, driving enable status, drive motor operating status, braking status, or a combination thereof.

[0063] If the reach truck is detected to be in a stopped state, the controller executes the method steps shown in S101; if the reach truck is detected to be in a non-stop state, the controller executes the method steps shown in S204.

[0064] S204, Control the electromagnetic clutch to open.

[0065] It should be noted that if the electromagnetic clutch remains engaged when the reach truck is not stopped, the transmission system may be in an incompatible locked or semi-locked state, which is detrimental to the normal power transmission and smooth operation of the reach truck. Conversely, by disengaging the electromagnetic clutch when the truck is not stopped, the reach truck's transmission system can be restored to a state suitable for driving, providing a basis for subsequent vehicle drive and state switching.

[0066] Therefore, when the controller determines that the reach truck is in a non-stop state, that is, the reach truck has entered a driving condition or has a tendency to drive, it controls the electromagnetic clutch to open. After the electromagnetic clutch is opened, the transmission system is disengaged, thereby preventing the reach truck from being affected by the continuous engagement of the clutch when it is not stopped.

[0067] This application embodiment detects whether a manual release of the parking gear is performed after the system is powered on. Based on this, it executes control logic to keep the electromagnetic clutch closed when the parking gear is not released and to continue detecting the parking status after the parking gear is released. In the non-parking state, the electromagnetic clutch is opened. This enables the reach truck to complete the initial state screening before entering the mast action control, thereby avoiding the use of incompatible clutch control methods under different working conditions after the system is powered on, improving the orderliness of the initial state management of the reach truck and the stability of the overall vehicle operation.

[0068] In one possible embodiment, after the controller executes the method steps shown in S101, if the gantry is not moving, the electromagnetic clutch is controlled to operate based on the switch state of the parking gear.

[0069] In this embodiment, after detecting that the reach truck is in a stopped state and obtaining the mast's action type, the controller can further identify whether the mast is in a state of inactivity, in addition to reclining or moving forward / backward. Inactivity of the mast can be understood as the mast not currently performing either reclining or forward / backward movement; the reach truck is in a stopped, standby, or intermittent state. At this time, the mast and forks do not generate significant action input, and the overall vehicle control requirements no longer primarily depend on the mast's action itself, but rather on the state of the parking position.

[0070] When the mast is not moving, the controller does not directly and permanently control the electromagnetic clutch to be in an open or closed state. Instead, it controls the electromagnetic clutch action based on the on / off state of the parking position. In other words, when the mast is not moving, the control of the electromagnetic clutch is not determined solely by the mast's movement, but rather by the current state of the parking position, ensuring that the electromagnetic clutch's action is adapted to the overall state of the reach truck. This approach avoids using a single, fixed control logic for the electromagnetic clutch when the mast is not moving, thereby improving the flexibility and rationality of the electromagnetic clutch control.

[0071] Furthermore, the on / off state of the parking gear indicates whether the reach truck is currently in a parking hold position. The controller adjusts the electromagnetic clutch action based on the parking gear's on / off state, allowing the reach truck to adapt its transmission system to the overall vehicle state even when the mast is not in motion. This helps to balance parking hold requirements with subsequent action switching needs.

[0072] In this embodiment, by controlling the electromagnetic clutch action based on the on / off state of the parking gear when the mast is not in motion, it is possible to avoid simply binding the mast's inactive state with a fixed clutch action, thereby improving the control adaptability of the reach truck in parking standby or work interval scenarios.

[0073] In one possible embodiment, the condition for determining that the reach truck is in a stopped state is: the vehicle speed of the reach truck is lower than a preset speed threshold, and the state of the vehicle speed being lower than the preset speed threshold continues for a first preset duration.

[0074] In this embodiment, the controller can determine whether the reach truck is currently in a stopped state by obtaining the vehicle speed information of the reach truck.

[0075] The vehicle speed can be the speed corresponding to the vehicle speed converted from the speed of the drive wheel and the speed of the drive motor, or other speed parameters that can characterize the driving state of the reach truck. This application does not limit this.

[0076] The preset speed threshold can be pre-set according to the model parameters of the reach truck, the characteristics of the drive system, and the actual operating conditions, and is used to distinguish whether the reach truck is in a parked state, a driving state, or a state with a driving tendency.

[0077] When the controller detects that the reach truck's speed is below a preset speed threshold, it does not immediately determine that the reach truck is in a stopped state. Instead, it further determines whether this low-speed state has persisted for a first preset duration. This is because, during actual operation, the reach truck's speed may temporarily fall below the preset speed threshold due to short-term deceleration, instantaneous vibrations, sampling fluctuations, or sensor measurement errors. If the controller directly determines a stopped state based solely on the speed detection result at a single moment, it is prone to misjudgment, thus affecting the accuracy of subsequent mast action recognition and clutch control. Therefore, by adding a time dimension constraint—the requirement that the low-speed state persist for a first preset duration—short-term speed fluctuations can be filtered out, thereby improving the stability and reliability of the stopped state determination.

[0078] In this embodiment, the controller only considers the reach truck to have truly entered a stopped state when the vehicle speed remains below a preset speed threshold for a first preset duration, and then proceeds to the subsequent mast action type identification and corresponding control process. This approach avoids erroneous state switching caused by instantaneous operating condition fluctuations, making the reach truck's control logic more stable and orderly.

[0079] The first preset duration can be set according to the response speed requirements of the reach truck, the sampling cycle of the control system, and the overall vehicle operating characteristics, so as to achieve a balance between the sensitivity and stability of the parking status determination.

[0080] When the first preset duration is set to a shorter duration, it is easier to quickly identify when a reach truck enters a parking state; when the first preset duration is set to a longer duration, it is easier to further suppress misjudgments caused by short-term fluctuations.

[0081] In practical applications, the first preset duration can be calibrated and optimized according to specific vehicle models and operational requirements. This embodiment does not impose specific limitations on this.

[0082] This application embodiment sets the determination condition for the reach truck to be in a stopped state to be that the vehicle speed is lower than a preset speed threshold and the state continues for a first preset duration. This can improve the accuracy and stability of the stopped state recognition and provide a reliable state determination basis for subsequent mast action type recognition and differentiated clutch control.

[0083] In one possible embodiment, when the gantry's action type is lifting and the electromagnetic clutch is engaged, the impact load generated by the gantry's swaying is transmitted to the drive motor, and the drive motor adaptively adjusts the reverse electromagnetic resistance torque according to the magnitude of the impact load.

[0084] In this embodiment, when the controller detects that the mast's movement is a lifting action, it controls the electromagnetic clutch to open, putting the reach truck's transmission system in an unlocked state. Unlike when the electromagnetic clutch is closed, which mechanically locks and restricts the transmission system's displacement, when the electromagnetic clutch is open, the transmission system is in a relatively relaxed connection state. The shaking and impact caused by factors such as inertia, changes in cargo weight, elastic deformation of the mast structure, and transmission chain clearance during the lifting process can be transmitted to the drive motor along the transmission path.

[0085] After the impact load generated by the gantry sway is transmitted to the drive motor, the drive motor does not output a fixed resistance torque. Instead, it adaptively adjusts the reverse electromagnetic resistance torque according to the magnitude of the impact load. In other words, when the gantry sway is significant and the corresponding impact load transmitted to the drive motor is large, the drive motor outputs a larger reverse electromagnetic resistance torque to enhance the absorption of the gantry sway impact. When the gantry sway weakens and the corresponding impact load decreases, the drive motor reduces the reverse electromagnetic resistance torque accordingly, thereby matching the drive motor's resistance output with the gantry sway state.

[0086] Because the degree of swaying during gantry lifting is usually not constant, but dynamically changes with the gantry position, load size, lifting speed, and instantaneous impact state, if the drive motor always outputs a fixed amount of reverse electromagnetic resistance torque, the resistance torque may be too small, resulting in insufficient sway suppression, or too large, affecting system response and stability. By enabling the drive motor to adaptively adjust the reverse electromagnetic resistance torque according to the magnitude of the impact load, the reverse electromagnetic resistance torque can be more specifically matched to the actual swaying state during gantry lifting, thus creating an adaptive damping effect.

[0087] Furthermore, the adaptive damping effect refers to the dynamic output of a corresponding reverse electromagnetic resistance torque by the drive motor based on the changes in impact load caused by gantry swaying, thereby suppressing the gantry swaying tendency. This reduces the frequency of gantry vibration, decreases the amplitude of gantry and cargo swaying, and shortens the duration of swaying. Simultaneously, since the impact load generated by gantry swaying is guided to the drive motor and absorbed by the reverse electromagnetic resistance torque, the impact is no longer primarily concentrated on the friction contact points of the electromagnetic clutch and the clearance points of the transmission system. Therefore, it also helps reduce impact wear on the electromagnetic clutch and related transmission components during lifting operations.

[0088] This embodiment does not output a preset resistance torque from the drive motor during gantry lifting. Instead, it adaptively adjusts the reverse electromagnetic resistance torque based on the actual impact load transmitted to the drive motor. Therefore, the drive motor can provide stronger impact absorption when the gantry sway is large, and reduce unnecessary resistance output when the gantry sway is small, thereby improving the adaptability and coordination of the control process while ensuring the gantry sway suppression effect.

[0089] In this embodiment, after the gantry is raised and lowered and the electromagnetic clutch is engaged, the impact load generated by the gantry swaying is transmitted to the drive motor. The drive motor then adaptively adjusts the reverse electromagnetic resistance torque according to the magnitude of the impact load. This enables the drive motor to form an adaptive damping effect that matches the gantry swaying state, thereby further improving the gantry sway suppression effect and reducing the wear risk of related components.

[0090] Figure 3 This is a flowchart illustrating another control method for reducing mast sway in a reach truck, provided in an embodiment of this application. Figure 3 As shown, in one possible embodiment, after the method steps shown in S102, the method further includes S301 and S302, which are described in detail below.

[0091] S301. Obtain the operating environment information of the reach truck.

[0092] Among them, the operating environment information is used to characterize the current operating site conditions of the reach truck, such as whether it is currently operating on flat ground or on a ramp.

[0093] It should be noted that the control requirements for the reverse electromagnetic resistance torque of reach trucks vary depending on the operating environment. On flat ground, a larger reverse electromagnetic resistance torque helps absorb the swaying impact generated during mast lifting, thereby improving mast swaying. However, on slopes, if the reverse electromagnetic resistance torque is too large, it may cause the reach truck to create a false parking effect on the slope, leading to the drive motor continuously outputting a large current, resulting in increased energy consumption and overheating.

[0094] S302. Based on the operating environment information, the parameters of the reverse electromagnetic resistance torque are adjusted so that the adjusted reverse electromagnetic resistance torque is used to suppress mast swaying under flat conditions, and the upper limit value under slope conditions is less than the parking braking torque of the reach truck.

[0095] It should be noted that the control objectives differ between flat ground and slope conditions: on flat ground, the focus is on absorbing the impact load during gantry lifting and lowering through the reverse electromagnetic resistance torque to reduce gantry sway; while on slopes, in addition to suppressing gantry sway, it is also necessary to avoid creating a false impression of parking on the slope due to excessive resistance torque. If an excessively large reverse electromagnetic resistance torque is still used on a slope, although it can suppress sway to some extent, it will cause the drive motor to maintain a large output for a long time, which is detrimental to the overall vehicle energy consumption control and component thermal management.

[0096] Specifically, when the reach truck is on level ground, the reverse electromagnetic resistance torque can be adjusted to absorb the impact of mast lifting and swaying, so as to better suppress mast swaying; when the reach truck is on a slope, the upper limit of the reverse electromagnetic resistance torque is limited to be less than the parking braking torque of the reach truck, so as to avoid relying solely on the reverse electromagnetic resistance torque output by the drive motor to keep the vehicle on the slope.

[0097] This application embodiment adjusts the parameters of the reverse electromagnetic resistance torque based on the operating environment information, which enables the reach truck to achieve better mast sway suppression under flat conditions and avoids misusing the reverse electromagnetic resistance torque as parking holding force under slope conditions, thus taking into account the control requirements under different operating conditions.

[0098] In one possible embodiment, the method steps shown in S302 can be implemented by Sa, which will be described in detail below.

[0099] Sa, based on the operating environment information, adjust the output current and / or magnetic field strength of the drive motor controller to regulate the magnitude of the reverse electromagnetic resistance torque.

[0100] The control parameters may include the output current and / or magnetic field strength of the drive motor controller. The controller can adjust the output current, magnetic field strength, or a combination of both of the drive motor controller based on whether the reach truck is currently on flat ground or on a slope, thereby changing the magnitude of the reverse electromagnetic resistance torque output by the drive motor.

[0101] It should be noted that the reverse electromagnetic resistance torque is not fixed, but can be adjusted through the control parameters of the drive motor. Therefore, under flat conditions, the output current and / or magnetic field strength can be appropriately increased to make the drive motor output a larger reverse electromagnetic resistance torque, so as to more effectively absorb the shaking impact generated during the lifting of the gantry. Under ramp conditions, the magnitude of the reverse electromagnetic resistance torque can be limited by reducing the output current and / or magnetic field strength, thereby avoiding the reverse electromagnetic resistance torque being too large and causing the reach forklift to create a false parking illusion on the ramp.

[0102] By adopting the above method, this embodiment can achieve the adjustment of the magnitude of the reverse electromagnetic resistance torque with a relatively direct control means, so that the reverse electromagnetic resistance torque output by the drive motor can be adapted to different working environments, thereby providing a basis for suppressing gantry sway under flat working conditions and controlling the upper limit of resistance torque under slope working conditions.

[0103] In another possible embodiment, the working environment information includes tilt information obtained through a tilt sensor.

[0104] In this embodiment, the reach truck can be equipped with a tilt sensor to detect the tilt of the work area where the reach truck is currently located and output the corresponding tilt information.

[0105] The method steps shown in S302 can be implemented by Sc, which will be explained in detail below.

[0106] Sc. Based on the slope coefficient corresponding to the inclination angle information and the preset correlation, the upper limit of the reverse electromagnetic resistance torque is adaptively adjusted.

[0107] The preset correlation is used to indicate the correspondence between the ramp coefficient and the reverse electromagnetic resistance torque parameter.

[0108] It should be noted that the requirements for reverse electromagnetic resistance torque differ between flat and ramp conditions for reach trucks: on flat ground, a higher upper limit of reverse electromagnetic resistance torque is permissible to more effectively suppress swaying during mast lifting; however, on ramps, the upper limit of reverse electromagnetic resistance torque needs to be limited to prevent excessive reverse electromagnetic resistance torque from creating a false parking effect on the ramp. Therefore, under different slope conditions, the controller can select different reverse electromagnetic resistance torque parameters based on the corresponding slope coefficient to ensure that the drive motor outputs an upper limit of reverse electromagnetic resistance torque that is adapted to the current operating environment.

[0109] The preset correlation is a linear function relationship, and the slope and intercept of the linear function relationship are calibrated by bench tests of reach trucks under no-load and full-load conditions.

[0110] Specifically, the resistance torque requirements of reach trucks under both unloaded and fully loaded conditions in different slope scenarios can be tested, and a linear correspondence between the ramp coefficient and the reverse electromagnetic resistance torque parameter can be established based on the test results. This method allows the setting of the upper limit value of the reverse electromagnetic resistance torque to better reflect the actual working characteristics of reach trucks, thereby improving the accuracy and adaptability of parameter adjustments.

[0111] This application embodiment obtains tilt angle information through a tilt angle sensor, and adaptively adjusts the upper limit of the reverse electromagnetic resistance torque based on the slope coefficient corresponding to the tilt angle information and the preset correlation relationship. This enables the reach truck to obtain reverse electromagnetic resistance torque parameters that are adapted to the current working conditions under different slope conditions, thereby taking into account both the mast sway suppression requirements and the control safety under slope conditions.

[0112] In the above embodiments, the identification of ramp conditions can be achieved automatically by tilt sensors or manually by the operator to trigger the ramp operation mode.

[0113] Specifically, when the operator confirms that the reach truck is in a ramp environment based on the current work site conditions, they can input a ramp operation mode trigger command to the controller through the corresponding operating mechanism. After receiving the trigger command, the controller identifies the current working condition of the reach truck as a ramp condition and executes the corresponding reverse electromagnetic resistance torque parameter adjustment and / or prompt control logic accordingly. By adopting the above method, even if the reach truck is not equipped with a tilt sensor, or the tilt sensor is not used as the main detection method in the current embodiment, it is still possible to identify and adapt to ramp operation scenarios, thereby improving the applicability of the technical solution of this application under different vehicle models and configuration conditions.

[0114] In another possible embodiment, when the reach truck is not equipped with a tilt sensor, controlling the drive motor to output a reverse electromagnetic resistance torque includes: controlling the drive motor to first output a first reverse electromagnetic resistance torque, and then switching to a second reverse electromagnetic resistance torque after a second preset time.

[0115] The second reverse electromagnetic resistance torque is less than the first reverse electromagnetic resistance torque.

[0116] It should be noted that when the reach truck is not equipped with a tilt sensor, the controller cannot directly identify whether the current working environment is flat or on a slope through the tilt information. Therefore, in the relevant control process, the controller can control the reach truck as if it were on a slope.

[0117] Specifically, when the operator releases the accelerator and depresses the brake pedal or engages the handbrake, the controller first controls the drive motor to output a first reverse electromagnetic resistance torque, enabling the vehicle to briefly hold on the slope, thus allowing time for the operator to perform subsequent active parking maneuvers. The magnitude of the first reverse electromagnetic resistance torque can be calibrated and determined based on the reach truck's design load capacity and climbing ability. Subsequently, after a second preset time, the controller controls the drive motor to switch to outputting a second reverse electromagnetic resistance torque, which is smaller than the first. Due to the smaller second reverse electromagnetic resistance torque, the reach truck will slowly roll down the slope, thus prompting the operator to promptly perform active parking maneuvers, preventing the vehicle from creating a false parking illusion by relying solely on the drive motor's output of a larger reverse electromagnetic resistance torque.

[0118] In flat terrain, the above control method will not adversely affect the normal operation of the vehicle, while the second reverse electromagnetic resistance torque can still offset the impact load generated during the lifting and lowering of the forks to a certain extent.

[0119] In one example, the second preset duration can be set to 1.5 seconds.

[0120] Furthermore, in some embodiments, the speed-holding function inherent in the drive motor controller can be used to achieve adaptive adjustment of the electromagnetic resistance torque. When the vehicle is stationary, the controller can set the target speed to 0. Under the impact load of gantry lifting or external disturbance, if the magnitude of the impact load acting on the drive motor is different, the drive motor controller will output different currents accordingly to automatically adjust the reverse electromagnetic resistance torque output by the drive motor. Thus, the reverse electromagnetic resistance torque can adaptively change with the actual impact load, thereby absorbing and canceling the impact of gantry swaying without adding additional complex control links.

[0121] This application embodiment, by employing a staged control method of first outputting a first reverse electromagnetic resistance torque and then switching to a second reverse electromagnetic resistance torque when no tilt sensor is configured, can adaptively control the reverse electromagnetic resistance torque output by the drive motor without relying on tilt angle detection.

[0122] In one possible embodiment, the method further includes an implementation of Sd, which is described in detail below.

[0123] Sd: When the reach truck is on a ramp, output a prompt message to remind the operator to perform an active parking operation.

[0124] The notification information includes text prompts on the vehicle display screen, icon prompts on the display screen, and / or audible and visual alarms from a buzzer.

[0125] Active parking operation includes parking by at least one of electromagnetic clutch locking, hydraulic braking and mechanical braking.

[0126] It should be noted that when operating on a slope, relying solely on the reverse electromagnetic resistance torque output by the drive motor to hold the vehicle can easily create a false sense of parking for the reach forklift. That is, the vehicle appears stationary, but in reality, it still relies on the drive motor to continuously output a large resistance torque for maintenance. In this situation, overall energy consumption increases, and the drive motor overheats, which is detrimental to the long-term stable operation and safety of the reach forklift. Therefore, when the reach forklift is detected to be on a slope, the controller does not use the reverse electromagnetic resistance torque output by the drive motor as the primary means of parking. Instead, it outputs a prompt message to guide the operator to perform an active parking maneuver. This method allows the operator to clearly understand that the vehicle is currently operating on a slope and to take appropriate parking measures in a timely manner, thus avoiding safety hazards caused by mistakenly believing the vehicle is already stably parked.

[0127] The controller can display text on the vehicle screen to indicate to the operator that the vehicle is on a slope and needs to be parked; it can also display preset icons on the vehicle screen to indicate to the operator that the vehicle is on a slope and needs to be parked; and it can also issue audible and visual alarms through a buzzer, warning light, or a combination thereof to enhance the warning effect.

[0128] The preset icon can be a ramp parking prompt icon pre-stored in the vehicle display system, used to graphically indicate that the reach truck is currently in ramp operation and prompt the operator to perform active parking operation.

[0129] The preset icons may include one or more combinations of ramp signs, parking signs, and warning signs, and this application does not limit them.

[0130] This application embodiment outputs prompt information when the reach truck is on a ramp, guiding the operator to perform active parking operation. This avoids the parking illusion problem caused by relying solely on the reverse electromagnetic resistance torque output by the drive motor for ramp holding, thereby improving the operational safety and reliability of the reach truck on ramps.

[0131] In the above embodiments, the electromagnetic clutch can be a brake pad type electromagnetic clutch. Specifically, in the de-energized state, the conical spring disengages the brake pads; in the energized state, the coil generates a magnetic field to attract the brake pads, thereby locking the clutch. By adopting this electromagnetic clutch structure, the electromagnetic clutch can switch between an open state and a closed state under the control of the controller to adapt to the control requirements of gantry lifting and forward / backward movement, respectively.

[0132] Furthermore, in some embodiments, the reach truck can be equipped with a rear-wheel electromagnetic clutch and optionally a front-wheel electromagnetic clutch, wherein the rear-wheel electromagnetic clutch and / or the front-wheel electromagnetic clutch can both adopt the above-mentioned brake pad type electromagnetic clutch structure.

[0133] In one possible embodiment, when the controller detects that the reach truck is on a ramp and limits the upper limit of the reverse electromagnetic resistance torque, the reach truck can slowly roll or slowly slope up the ramp. That is, in ramp conditions, the controller does not output excessive reverse electromagnetic resistance torque from the drive motor to keep the reach truck stationary; instead, it ensures that the upper limit of the reverse electromagnetic resistance torque is less than the parking brake torque of the reach truck, thereby avoiding the illusion of ramp parking. In this case, the slow rolling or slow slope movement of the reach truck can serve as one of the prompt signals to the operator, combined with text prompts on the vehicle display screen, icon prompts on the display screen, and / or audible and visual alarms, prompting the operator to perform active parking operations in a timely manner. This method avoids the increased energy consumption, aggravated drive motor heating, and operational safety hazards caused by relying solely on the reverse electromagnetic resistance torque output by the drive motor for ramp holding.

[0134] In summary, the control method for mitigating mast sway in reach trucks provided in this application targets the mast lifting and lowering motion, the primary scenario causing mast sway. Upon detecting the mast lifting action, the electromagnetic clutch is disengaged, placing the transmission system in an unlocked state. The reverse electromagnetic resistance output from the drive motor provides rectangular damping, thereby absorbing and offsetting the impact load generated by the mast sway. Compared to related technologies that primarily rely on mechanical locking to limit displacement, this application more effectively reduces the swaying impact during mast lifting and lowering, decreasing the amplitude of mast and cargo sway, reducing vibration frequency, and shortening the duration of sway. This is particularly beneficial in fully loaded, high-level stacking operations, improving the stability and efficiency of forklift operations.

[0135] Furthermore, this application keeps the electromagnetic clutch in the open state during the gantry lifting operation, maintaining a relatively relaxed transmission system. The impact load generated by the gantry swaying is no longer primarily concentrated on the brake pads and transmission clearance of the electromagnetic clutch, but is absorbed by the reverse electromagnetic resistance torque output by the drive motor. This reduces the continuous vibration and friction problem of the brake pads caused by clutch lock-up in related technologies, and reduces the clearance wear of the gearbox and related transmission components caused by repeated impact loads. This helps extend the service life of the electromagnetic clutch, drive motor, and related transmission components, reducing equipment maintenance costs.

[0136] Furthermore, this application does not employ the same control strategy for all mast movements, but rather implements differentiated control based on the type of mast movement: when the mast performs a lifting action, the focus is on suppressing mast sway by opening the electromagnetic clutch and outputting a reverse electromagnetic resistance torque; when the mast performs a forward or backward movement action, the focus is on limiting the forward or backward movement of the vehicle body by closing the electromagnetic clutch. This differentiated clutch control logic can adapt to the control requirements of two different operating scenarios—mast lifting and forward / backward movement—thereby balancing the goals of mast sway suppression and vehicle body displacement limitation, thereby improving the stability and operational accuracy of the reach truck during parking operations.

[0137] This application also allows for adaptive adjustments to the reverse electromagnetic resistance torque based on the operating environment of the reach truck. On level ground, the reverse electromagnetic resistance torque can be more effectively used to absorb the swaying impact during mast lifting. On slopes, by limiting the upper limit of the reverse electromagnetic resistance torque to be less than the parking braking torque of the reach truck, the false parking effect on slopes is avoided, as the reach truck relies solely on the reverse electromagnetic resistance torque output by the drive motor. Furthermore, this application can also prompt the operator to perform active parking maneuvers via text prompts on the onboard display and / or audible and visual alarms on slopes. This helps avoid increased vehicle energy consumption, aggravated drive motor overheating, and operational safety hazards caused by excessive resistance torque, thereby improving the operational safety and reliability of the reach truck on slopes.

[0138] Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 4 As shown, the electronic device 400 provided in this embodiment includes a memory 401 and a processor 402.

[0139] The memory 401 can be a separate physical unit, connected to the processor 402 via a bus 403. Alternatively, the memory 401 and processor 402 can be integrated and implemented in hardware. The memory 401 stores program instructions, which the processor 402 calls to execute the operations performed by the controller in any of the above method embodiments.

[0140] Optionally, when some or all of the methods in the above embodiments are implemented by software, the electronic device 400 may also include only the processor 402. A memory 401 for storing programs is located outside the electronic device 400, and the processor 402 is connected to the memory via circuits / wires to read and execute the programs stored in the memory. The processor 402 may be a central processing unit (CPU), a network processor (NP), or a combination of a CPU and an NP. The processor 402 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0141] Memory 401 may include volatile memory, such as random-access memory (RAM); memory may also include non-volatile memory, such as flash memory, hard disk drive (HDD) or solid-state drive (SSD); memory may also include combinations of the above types of memory.

[0142] For example, this application provides a chip including: an interface circuit and a logic circuit. The interface circuit is used to receive signals from other chips outside the chip and transmit them to the logic circuit, or to send signals from the logic circuit to other chips outside the chip. The logic circuit is used to perform the operations performed by the controller in the above method embodiments.

[0143] For example, this application provides a computer-readable storage medium having computer program instructions stored thereon, which are executed by the processor of an electronic device to cause the electronic device to perform the operations performed by the controller in the above method embodiments.

[0144] For example, this application provides a computer program product that, when run on an electronic device, causes the electronic device to perform the operations executed by the controller in the above method embodiments.

[0145] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for reducing mast sway in a reach truck, applied to a reach truck, the reach truck including an electromagnetic clutch, a drive motor, and a motor controller, characterized in that, The method includes: After detecting that the reach truck is in a stopped state, the action type of the mast is obtained; If the action type of the gantry is lifting action, control the electromagnetic clutch to open, so that the transmission system is in an unlocked state, and control the drive motor to output reverse electromagnetic resistance torque to absorb the impact load generated by the gantry swaying; If the mast's movement is a forward or backward movement, the electromagnetic clutch is controlled to close to limit the vehicle's forward or backward movement.

2. The method according to claim 1, characterized in that, Prior to obtaining the action type of the gantry, the method further includes: After the reach truck system is powered on, it is checked whether there is a manual release of the parking gear. If there is no manual disengagement of the parking gear, the electromagnetic clutch remains closed; If a manual release of the parking position is performed, check whether the reach truck is in a parked state. If the reach truck is not stopped, control the electromagnetic clutch to open.

3. The method according to claim 1, characterized in that, After obtaining the action type of the gantry, the method further includes: If the gantry is not in motion, the electromagnetic clutch is controlled based on the on / off state of the parking gear.

4. The method according to claim 1, characterized in that, The condition for determining that the reach truck is in a stopped state is: the vehicle speed of the reach truck is lower than a preset speed threshold, and the state of the vehicle speed being lower than the preset speed threshold continues for a first preset duration.

5. The method according to claim 1, characterized in that, When the gantry's action type is lifting and the electromagnetic clutch is engaged, the impact load generated by the gantry's swaying is transmitted to the drive motor, and the drive motor adaptively adjusts the reverse electromagnetic resistance torque according to the magnitude of the impact load.

6. The method according to claim 1, characterized in that, After controlling the drive motor to output a reverse electromagnetic resistance torque, the method further includes: Obtain the operating environment information of the reach truck; Based on the operating environment information, the parameters of the reverse electromagnetic resistance torque are adjusted so that the adjusted reverse electromagnetic resistance torque is used to suppress mast sway under flat conditions, and the upper limit value under slope conditions is less than the parking braking torque of the reach truck.

7. The method according to claim 6, characterized in that, The step of adjusting the parameters of the reverse electromagnetic drag torque based on the operating environment information includes: Based on the operating environment information, the output current and / or magnetic field strength of the drive motor controller are adjusted to regulate the magnitude of the reverse electromagnetic resistance torque.

8. The method according to claim 6, characterized in that, The working environment information includes tilt information obtained through a tilt sensor; The step of adjusting the parameters of the reverse electromagnetic drag torque based on the operating environment information includes: Based on the ramp coefficient corresponding to the tilt angle information and the preset correlation, the upper limit of the reverse electromagnetic resistance torque is adaptively adjusted; wherein, the preset correlation is used to indicate the correspondence between the ramp coefficient and the reverse electromagnetic resistance torque parameter; the preset correlation is a linear function relationship, and the slope and intercept of the linear function relationship are obtained by bench testing of the reach truck under no-load and full-load conditions.

9. The method according to claim 1, characterized in that, When the reach truck is not equipped with a tilt sensor, controlling the drive motor to output a reverse electromagnetic resistance torque includes: The drive motor is controlled to first output a first reverse electromagnetic resistance torque, and then switch to a second reverse electromagnetic resistance torque after a second preset time period, wherein the second reverse electromagnetic resistance torque is less than the first reverse electromagnetic resistance torque.

10. The method according to claim 1, characterized in that, The method further includes: When the reach truck is on a ramp, a prompt message is output, which prompts the operator to perform an active parking operation. The prompts include text prompts on the vehicle display screen, icon prompts on the display screen, and / or audible and visual alarms from a buzzer. The active parking operation includes parking by at least one of the following: electromagnetic clutch locking, hydraulic braking, and mechanical braking.

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