Control method, control system and working machine for a working machine

Abstract

The invention relates to a control method for a working machine having a work device comprising a work unit and an electric cylinder for driving the work unit, the electric cylinder comprising an electric motor, the work device further comprising an operating device by means of which operating commands can be provided for the electric cylinder, the method comprising: obtaining an operating command from the operating device, determining whether the operating command is null, obtaining a travel speed of the working machine, determining whether the travel speed is greater than a travel stability threshold, in the event that the operating command is not null and the travel speed is greater than the travel stability threshold, activating a travel stability module, the travel stability module ensuring travel stability of the working machine by controlling the electric motor of the work device. The invention also relates to a control system and to a working machine.

Description

Technical Field

[0001] This invention relates to a control method, a control system, and the machinery itself, particularly a loader. The machinery includes a working device driven by an electric cylinder. Background Technology

[0002] Because construction machinery has adjustable working devices, its center of gravity changes with the posture or position of these devices. Therefore, during operation, especially on uneven surfaces, the entire construction machinery may become unstable.

[0003] Taking loaders as an example, the posture and position of the bucket directly affect the overall center of gravity distribution of the loader. When a loader travels on uneven roads, especially during transport when the bucket is loaded with material, the bucket is often fixed relative to the boom. At this time, the boom, boom lifting cylinder, and frame constitute a structure similar to a rigid body. Under these circumstances, road undulations or bumps can be transmitted to the machine body, causing it to sway around the axle (especially the front axle). In extreme cases, this swaying may even cause the rear axle to briefly lift off the ground, resulting in severe tilting of the machine body. This not only makes it easier for the loaded material to spill but also causes severe shaking in the cab, greatly increasing the difficulty of operation for the user, reducing driving comfort, and in severe cases, even endangering the user's safety.

[0004] For construction machinery using hydraulic cylinders to drive its working devices, the hydraulic system has built-in pressure control functionality. Therefore, by adjusting the working pressure and flow rate of the hydraulic cylinders, vehicle body sway can be reduced to some extent, improving driving stability. However, for construction machinery using electric cylinders to drive its working devices, the control method of electric cylinders is relatively simple and lacks the flexibility and adaptability of hydraulic systems. Therefore, it is difficult to achieve the same level of driving stability control. When facing complex and changing driving environments, this type of construction machinery often relies more on the user's experience and skills for manual adjustments to ensure safe and stable operation. Summary of the Invention

[0005] The present invention aims to solve one or more of the above-mentioned technical problems.

[0006] According to a first aspect of the present invention, a control method for engineering machinery is provided. The engineering machinery has a working device, which includes a working unit and an electric cylinder for driving the working unit. The electric cylinder includes a motor. The working device also includes an operating device, by means of which operating commands can be provided to the electric cylinder.

[0007] The method includes:

[0008] Receive operation commands from the operating device.

[0009] Determine if the operation command is empty.

[0010] To obtain the travel speed of construction machinery,

[0011] Determine whether the driving speed exceeds the driving stability threshold.

[0012] When the operating command is not empty and the driving speed is greater than the driving stability threshold, the driving stability module is activated. This module ensures the driving stability of the construction machinery by controlling the motor of the working device. This invention also relates to a control system and construction machinery.

[0013] The method according to the present invention achieves the following advantages:

[0014] By utilizing a driving stability module, the safety and stability of construction machinery under complex working conditions are improved. This method can ensure, in a simple way, that construction machinery can effectively avoid potential risks during operation, protecting the safety of operators and the integrity of the equipment.

[0015] The present invention also relates to corresponding control systems and engineering machinery. Attached Figure Description

[0016] Figure 1 This is a flowchart of an exemplary embodiment of a control method for engineering machinery.

[0017] Figure 2 This is a schematic diagram of the first implementation of the driving stability module.

[0018] Figure 3 This is a schematic diagram of the second implementation of the driving stability module. Detailed Implementation

[0019] The control method, control system, and engineering machinery according to the present invention will now be described with reference to the accompanying drawings and specific embodiments. However, exemplary embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the invention comprehensive and complete, and to fully convey the concept of exemplary embodiments to those skilled in the art.

[0020] Construction machinery is equipped with a working device driven by an electric cylinder. This working device includes, for example, a working unit and an electric cylinder for driving the working unit. Taking a loader as an example, the working unit may include a bucket for loading materials and a boom for lifting the bucket. The electric cylinder includes, for example, a motor as a power source, a motor controller for controlling the motor's movement, and an actuator for performing the extension and retraction movements. In addition, the working device also includes a user-operated control device that provides operating commands to the electric cylinder.

[0021] Here, the working unit operates in response to commands issued by an operating device, such as a control handle. Furthermore, to ensure precision and safety of control, the working unit also includes sensor devices. These sensor devices include, for example, stroke sensors for the electric cylinders, IMU (Inertial Measurement Unit) sensors for the lifting arm, and sensors for monitoring the overall speed and acceleration of the construction machinery, or other measuring devices.

[0022] Figure 1 A schematic flowchart of a control method for construction machinery according to the present invention is shown. This control method aims to improve the safety and stability of construction machinery under various complex working conditions. The method aims to ensure that construction machinery can effectively avoid potential risks during operation, protecting the safety of operators and the integrity of the equipment.

[0023] In this control method, an operation command from the operating device is acquired, and it is determined whether the operation command is empty (S01). If it is determined that the operation command from the operating device is not empty (i.e., there is an operation command for the corresponding action of the specified working unit), the control method ends and the driving stability module is not activated. Then, for example, the system switches to the corresponding working unit operation mode.

[0024] If the operation command from the operating device is empty (i.e., there is no operation command specifying the corresponding action of the working unit), proceed to the next step S02. In step S02, the travel speed of the construction machinery is acquired and it is determined whether the travel speed is greater than the travel stability threshold. If the travel speed is not greater than the travel stability threshold, this control method ends and the travel stability module is not activated. In this case, since the travel speed is relatively slow, it is considered a low-risk situation that does not require additional control of travel stability, so the travel stability module is not activated. In this case, the electric cylinder is generally locked, thus fixing the posture of the working unit.

[0025] If the driving speed exceeds the driving stability threshold, proceed to step S03. In step S03, it is determined whether the driving stability switch is on. Here, the driving stability switch can be a physical switch, such as a mechanical switch located in the driver's cab for manual operation by the user, or an operating interface displayed on a touch screen device. Of course, the driving stability switch can also be a virtual switch, such as a software switch triggered or activated by certain conditions. If the driving stability switch is off, this control method ends. The setting of the driving stability switch gives the user control over the activation of the driving stability module, allowing them to customize or adjust the activation conditions according to personal needs or specific situations.

[0026] Of course, an implementation without a stability control switch can also be conceived. Furthermore, other possible implementations exist; for example, the execution order of the stability control switch status determination step, the operation command acquisition and determination step, and the driving speed acquisition and determination step can be adjusted according to actual needs. These steps can be performed sequentially or synchronously in parallel.

[0027] With the driving stability switch turned on, proceed to the next step, S04. In step S04, the driving stability module is activated, which ensures the driving stability of the construction machinery by controlling the motor of the working device.

[0028] The following describes in detail how the driving stability module works. The driving stability module is implemented, for example, as a state machine for controlling the motor. A first embodiment of the driving stability module is described below. Figure 2 As shown in the diagram. In this embodiment, three different control states are defined. The driving stability module acquires the instantaneous driving speed of the construction machinery in real time and switches between these three control states based on the instantaneous driving speed.

[0029] Here, the driving stability module acquires and stores the parameter: the requested motor output torque value. In this embodiment, when the driving stability module starts working, or during initialization, this requested motor output torque value is set to the actual motor output torque at that moment. Of course, this parameter can also be initialized to the theoretical motor output torque expected at the current moment, or the motor output torque calculated in other ways.

[0030] As described above, the driving stability module includes three states: control state A, control state B, and control state C. In control state A, the electric cylinder is locked, and the parameter "requested motor output torque value" remains unchanged. When the speed of the construction machinery increases above the threshold for releasing the electric cylinder lock, the driving stability module switches from control state A to control state B.

[0031] In control state B, the electric cylinder's lock-up state is released, and the electric cylinder control mode is set to speed control mode. In speed control mode, the desired extension / retraction speed of the electric cylinder is set to zero, and the motor is controlled based on the desired extension / retraction speed. Simultaneously, the parameter "requested motor output torque value" is updated based on the actual output torque and actual speed of the electric cylinder.

[0032] When the speed of the construction machinery is below the electric cylinder lock-up speed threshold, the driving stability module switches from control state B to control state A. When the speed of the construction machinery is above the torque control activation speed threshold, the driving stability module switches from control state B to control state C.

[0033] In control state C, the electric cylinder control mode is defined as torque control mode. In torque control mode, the motor is controlled based on the parameter "requested motor output torque value". Optionally, a maximum speed limit can be specified. Here, the parameter "requested motor output torque value" is modified based on the maximum speed limit, and the motor is controlled based on the modified parameter "requested motor output torque value".

[0034] The specific value of the maximum speed limit is determined based on the extension and retraction range of the electric cylinder. This setting aims to prevent the electric cylinder from exceeding the pre-specified safe range during extension and retraction, thereby ensuring that the construction machinery maintains sufficient ground clearance during operation. Simultaneously, this limit also prevents excessive height issues caused by improper lifting operations, thus guaranteeing the overall safety and stability of the operation.

[0035] When the travel speed of the construction machinery is lower than the torque control shutdown speed threshold and higher than the electric cylinder lock-up release speed threshold, the driving stability module switches from control state C to control state B.

[0036] Here, the electric cylinder lock-up speed threshold is lower than the electric cylinder unlock-up speed threshold. The electric cylinder unlock-up speed threshold is lower than the torque control shutdown speed threshold. The torque control shutdown speed threshold is lower than the torque control activation speed threshold. The difference between the electric cylinder lock-up speed threshold and the electric cylinder unlock-up speed threshold is, for example, greater than a first interval value, thereby avoiding repeated switching of the state machine between control state A and control state B caused by speed value fluctuations. Similarly, the difference between the electric cylinder unlock-up speed threshold and the torque control shutdown speed threshold is greater than a second interval value, and the difference between the torque control shutdown speed threshold and the torque control activation speed threshold is greater than a third interval value. These interval values ​​can be set according to specific circumstances; they can be the same or different from each other.

[0037] When the driving stability module is activated, it can be pre-set to directly enter one of the control states, such as control state B, and then the specific control state is determined based on the real-time acquired driving speed. Of course, the control state can also be specified based on the driving speed at the moment the driving stability module is activated.

[0038] exist Figure 3 The diagram illustrates a second embodiment of a state machine for controlling a motor. In this second embodiment, two different control states are defined. To distinguish them from the first embodiment, the terms Control State I and Control State II will be used hereinafter to refer to the different control states. Similarly, the travel speed of the construction machinery is acquired in real time, and the system switches between these two control states based on the travel speed.

[0039] In control state I, the electric cylinder is locked, and the average chassis pitch angle over a given period is calculated based on chassis pitch angle data from the previous period. This average chassis pitch angle is updated in real time and stored. This chassis pitch angle data can be acquired through chassis attitude sensors. This calculated average chassis pitch angle can be considered as the average angle between the current road surface and the horizontal plane.

[0040] In control state II, the electric cylinder is unlocked, and the electric cylinder control mode is set to speed control mode. In this speed control mode, the chassis pitch angle and the average chassis pitch angle are updated in real time. Similarly, the average chassis pitch angle can be considered as the angle between the road surface and the horizontal plane.

[0041] Based on the current chassis pitch angle, average chassis pitch angle, vehicle speed, electric cylinder extension / retraction amount, and the structural data of the working unit, the velocity of the working unit's center of gravity in the direction perpendicular to the road surface is estimated. Here, a mapping table showing the relationship between the working unit's center of gravity and the electric cylinder extension / retraction amount can be used as the structural data for the aforementioned working unit. This mapping table can be pre-stored in the construction machinery. The mapping table is determined based on the specific working unit's construction. Alternatively, other structural data, such as characteristic curves or functions, can also be used.

[0042] For example, for loaders, mapping tables can be determined separately for the case where the bucket is fully loaded with the rated load and for the case where it is half-loaded. Alternatively, a simplified mapping table can be determined only for the case where the bucket is fully loaded with the rated load. To simplify the calculation process, the slight influence of the extension / retraction of the tilting cylinder on the material's center of gravity can be ignored. Therefore, the relationship between the relative position of the bucket's center of gravity with respect to the chassis and the extension / retraction of the lifting cylinder can be easily estimated.

[0043] The target speed of the working unit's center of gravity in the direction perpendicular to the road surface is set to zero. Based on the estimated speed of the working unit in the direction perpendicular to the road surface, a speed command for motor control is derived. The motor is then controlled based on this speed command.

[0044] When the speed of the construction machinery is below the electric cylinder locking speed threshold, the control routine switches from control state II to control state I. When the speed of the construction machinery is above the electric cylinder unlocking speed threshold, the control routine switches from control state I to control state II.

[0045] Here, the electric cylinder locking speed threshold is lower than the electric cylinder unlocking speed threshold. The difference between the electric cylinder locking speed threshold and the electric cylinder unlocking speed threshold is greater than the fourth interval value.

[0046] When the driving stability module is activated, it can be forcibly entered into one of the control states, such as control state II, and then the specific control state is determined based on the real-time acquired driving speed. Of course, the control state can also be determined based on the driving speed at the moment the driving stability module is activated.

[0047] The present invention also relates to a corresponding control system for construction machinery, particularly loaders. This control system may include a data processing device configured to execute embodiments of the method according to the invention. For this purpose, the data processing device may have at least one microprocessor and / or at least one microcontroller and / or at least one FPGA and / or at least one DSP. In particular, a CPU, GPU, or NPU may be used as the microprocessor. Furthermore, the data processing device may have program code configured to implement embodiments of the method according to the invention when executed by the data processing device. The program code may be stored in the memory of the data processing device. The data processing device may, for example, be based on at least one circuit board and / or at least one SoC.

[0048] Finally, the present invention also relates to construction machinery having a working device, the working device including a working unit and an electric cylinder for driving the working unit, the electric cylinder including a motor, the working device further including an operating device by means of which operating commands can be provided to the electric cylinder, and the construction machinery further including a control system as described above.

[0049] Industrial applicability

[0050] The following uses a loader as an example to illustrate how the above method works.

[0051] In this method, an operation command is obtained from the control handle, and it is determined whether the operation command is empty. If the user does not input an operation command using the handle, i.e., the user does not operate the loader's bucket, the next step is to obtain the travel speed of the construction machinery. If the travel speed is greater than the travel stability threshold and the travel stability switch is turned on, the travel stability module is activated.

[0052] Here, taking the first embodiment of the driving stability module as an example, the driving stability module is implemented as a state machine including control state A, control state B, and control state C. Here, the module switches between these three states based on the instantaneous driving speed. For example, when the speed is higher than the electric cylinder lock-up speed threshold and lower than the torque control shut-off speed threshold, the driving stability module controls the motor in control state B. In this state, the electric cylinder lock-up is released, and the electric cylinder control mode is defined as speed control mode. In speed control mode, the desired extension / retraction speed of the electric cylinder is set to zero, and the motor is controlled based on the desired extension / retraction speed. Simultaneously, the parameter "requested motor output torque value" is updated based on the actual output torque and actual speed of the electric cylinder.

[0053] The steps mentioned in the method according to the invention can be performed in a specified order. However, these steps can also be performed in a different order or in parallel, provided it is technically feasible. The method according to the invention can be performed in one of its embodiments, but can also be performed in different ways, such as by a specific group of steps, or without performing a certain step. However, in principle, other steps, even those not mentioned, can also be performed.

[0054] Obviously, those skilled in the art can make various modifications and variations to the embodiments disclosed above without departing from the scope or spirit of the invention. Other embodiments of the invention will be apparent to those skilled in the art based on the practice of the invention disclosed in this specification. This specification and the examples disclosed herein should be considered merely illustrative.

Claims

1. A control method for construction machinery, the construction machinery having a working device, the working device including a working unit and an electric cylinder for driving the working unit, the electric cylinder including a motor, the working device further including an operating device, by means of which operating commands can be provided to the electric cylinder, characterized in that, The method includes: Receive operation commands from the operating device. Determine if the operation command is empty. To obtain the travel speed of construction machinery, Determine whether the driving speed exceeds the driving stability threshold. When the operation command is not empty and the driving speed is greater than the driving stability threshold, the driving stability module is activated. This driving stability module ensures the driving stability of the construction machinery by controlling the motor of the working device.

2. The control method according to claim 1, characterized in that, The method also includes: determining whether the driving stability switch is turned on, and activating the driving stability module only when the driving stability switch is turned on.

3. The control method according to claim 1, characterized in that, The driving stability module is constructed as a state machine containing at least two different control states. The state machine acquires the instantaneous driving speed of the construction machinery in real time and switches between the at least two different control states based on the instantaneous driving speed.

4. The control method according to claim 3, characterized in that, The driving stability module includes control state A, in which the electric cylinder is locked and the parameter "request motor output torque value" remains unchanged.

5. The control method according to claim 4, characterized in that, The driving stability module includes a control state B, in which the locking state of the electric cylinder is released and the control mode of the electric cylinder is set to speed control mode.

6. The control method according to claim 5, characterized in that, In speed control mode, the desired extension speed of the electric cylinder is set to zero, and the motor is controlled based on the desired extension speed; the parameter "request motor output torque value" is updated based on the actual output torque and actual speed of the electric cylinder.

7. The control method according to claim 5, characterized in that, The driving stability module includes a control state C. In control state C, the locking state of the electric cylinder is released, and the control mode of the electric cylinder is defined as torque control mode. In torque control mode, the motor is controlled based on the parameter "request motor output torque value".

8. The control method according to claim 7, characterized in that, In control state C, the parameter "request motor output torque value" is modified based on the predetermined maximum speed limit, and the motor is controlled based on the modified parameter "request motor output torque value".

9. The control method according to claim 7, characterized in that, The driving stability module is constructed as follows: When the speed of the construction machinery is higher than the speed threshold for releasing the electric cylinder lock and lower than the speed threshold for activating torque control, the driving stability module switches from control state A to control state B. When the travel speed of the construction machinery is lower than the electric cylinder lock-up speed threshold, the driving stability module switches from control state B to control state A. When the speed of the construction machinery exceeds the speed threshold for activating torque control, the driving stability module switches from control state B to control state C. When the travel speed of the construction machinery is lower than the torque control shutdown speed threshold and higher than the electric cylinder lock-up release speed threshold, the driving stability module switches from control state C to control state B.

10. The control method according to claim 9, characterized in that, The electric cylinder locking speed threshold is lower than the electric cylinder unlocking speed threshold; The speed threshold for releasing the electric cylinder lock is lower than the speed threshold for closing torque control. The speed threshold for disabling torque control is lower than the speed threshold for enabling torque control. The difference between the electric cylinder locking speed threshold and the electric cylinder unlocking speed threshold is greater than the first interval value; The difference between the speed threshold for turning off torque control and the speed threshold for turning on torque control is greater than the third interval value.

11. The control method according to claim 3, characterized in that, The driving stability module includes control state I, in which the electric cylinder is locked and the average chassis pitch angle during this period is calculated based on the chassis pitch angle data over a previous period.

12. The control method according to claim 11, characterized in that, The driving stability module includes a control state II, in which the locking state of the electric cylinder is released and the electric cylinder control mode is set to speed control mode. In this speed control mode, The system updates the chassis pitch angle and its average value in real time. Based on the updated chassis pitch angle, average value, vehicle speed, electric cylinder extension / retraction, and structural data of the working unit, it estimates the real-time speed of the working unit's center of gravity in the direction perpendicular to the road surface. The target velocity of the working unit's center of gravity in the direction perpendicular to the road surface is set to zero. Based on the estimated real-time velocity of the working unit's center of gravity in the direction perpendicular to the road surface, a speed command for motor control is derived. The motor is controlled based on this speed command.

13. The control method according to claim 12, characterized in that, The driving stability module is constructed as follows: When the speed of the construction machinery exceeds the threshold for releasing the electric cylinder lock, the driving stability module switches from control state I to control state II. When the speed of the construction machinery is lower than the electric cylinder lock-up speed threshold, the driving stability module switches from control state II to control state I.

14. The control method according to claim 13, characterized in that, The driving stability module is constructed as follows: When the speed of the construction machinery exceeds the threshold for releasing the electric cylinder lock, the driving stability module switches from control state I to control state II. When the travel speed of the construction machinery is lower than the electric cylinder lock-up speed threshold, the driving stability module switches from control state II to control state I. The electric cylinder locking speed threshold is lower than the electric cylinder unlocking speed threshold; The difference between the electric cylinder locking speed threshold and the electric cylinder unlocking speed threshold is greater than the fourth interval value.

15. A control system for engineering machinery, the control system comprising a data processing device configured to perform the control method according to any one of claims 1-14.

16. An engineering machine having a working device, the working device including a working unit and an electric cylinder for driving the working unit, the electric cylinder including a motor, the working device further including an operating device by means of which operating commands can be provided to the electric cylinder, the engineering machine further including the control system according to claim 15.

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