Steering control methods for construction machinery and construction machinery

Abstract

This application discloses a steering control method for construction machinery and the construction machinery itself. The construction machinery includes a steering cylinder, an electric motor, and a steering wheel. The steering cylinder is used to drive the construction machinery to steer. The electric motor is driven by the steering cylinder. The electric motor is signal-connected to the steering wheel to drive the steering cylinder to move when the steering wheel is turned. The steering control method includes the following steps: acquiring the load state of the construction machinery and acquiring a corresponding set speed and an initial speed based on the load state, wherein the initial speed is less than the set speed; acquiring the movement of the steering wheel; and controlling the electric motor to operate at the initial speed when the steering wheel is turned, and controlling the electric motor to operate at the set speed after a set time period. When the operator starts to turn the steering wheel, the electric motor is controlled to operate at a lower initial speed to reduce the impact when the steering cylinder is first started, thereby improving steering stability. After a set time, the electric motor operates at the set speed to ensure the smoothness of the steering process.

Description

Technical Field

[0001] This application relates to the field of engineering machinery technology, and in particular to a steering control method for engineering machinery and engineering machinery. Background Technology

[0002] Currently, the pure electric loaders developed by major OEMs retain the original hydraulic system and mechanical actuators. The steering system still uses the original articulated hydraulic steering, but the power source has been changed to an electric motor driving the hydraulic pump. Because the steering pump and the working pump are driven by the same motor, and the motor uses constant speed control, there is a large mechanical inertial impact on the steering cylinder when steering starts and stops, resulting in poor steering stability and a poor driving experience.

[0003] It should be noted that the statements in this background section only provide background information relevant to this application and do not necessarily constitute prior art. Summary of the Invention

[0004] This application provides a steering control method for engineering machinery and the engineering machinery itself, to improve steering stability.

[0005] This application provides a steering control method for construction machinery, the construction machinery including a steering cylinder, an electric motor, and a steering wheel. The steering cylinder is used to drive the construction machinery to steer. The electric motor is drivenly connected to the steering cylinder. The electric motor is signal-connected to the steering wheel to operate when the steering wheel is rotated, thereby driving the steering cylinder to actuate. The steering control method includes the following steps:

[0006] The load status of the construction machinery is obtained, and the corresponding set speed and initial speed are obtained based on the load status. The initial speed is less than the set speed.

[0007] Acquiring the steering wheel action; and

[0008] When the steering wheel is turned, the control motor operates at an initial speed and then operates at a set speed after a set time period.

[0009] In some embodiments, the load state includes no-load, half-load, and full-load. Obtaining the corresponding set speed and initial speed according to the load state includes: making the set speed value different under different load states.

[0010] In some embodiments, the load state includes no-load, half-load, and full-load. Obtaining the corresponding set speed and initial speed according to the load state includes: making the value of the initial speed different under different load states.

[0011] In some embodiments, the construction machinery includes a front frame and a rear frame rotatably connected to the front frame. The steering control method further includes: acquiring the real-time acceleration of the front frame relative to the rear frame during the operation of the motor at a set speed; and, if the real-time acceleration is less than an acceleration threshold, controlling the speed of the motor to decrease by a first set value relative to the set speed, so that the speed of the front frame relative to the rear frame is reduced to zero.

[0012] In some embodiments, the load state includes no-load, half-load, and full-load. Controlling the motor speed to decrease relative to a set speed by a first set value includes: adjusting the magnitude of the first set value according to the load state, so that the first set value is different under different load states.

[0013] In some embodiments, the load state includes no load, half load, and full load. When the real-time acceleration is less than an acceleration threshold, the method includes: adjusting the magnitude of the acceleration threshold according to the load state so that the acceleration threshold differs under different load states.

[0014] In some embodiments, the steering control method further includes: controlling the rotational speed of the motor to maintain a set rotational speed when the real-time acceleration is greater than or equal to an acceleration threshold.

[0015] In some embodiments, the construction machinery includes a front frame and a rear frame rotatably connected to the front frame. The steering control method further includes: acquiring a real-time steering angle of the front frame relative to the rear frame while the motor is operating at a set speed; and, if the real-time steering angle is greater than a steering angle threshold, controlling the speed of the motor to decrease by a second set value relative to the set speed, so that the steering speed of the front frame relative to the rear frame is reduced to zero.

[0016] In some embodiments, the load state includes no-load, half-load, and full-load. Controlling the motor speed to decrease relative to a set speed by a second set value includes: adjusting the magnitude of the second set value according to the load state, so that the second set value is different under different load states.

[0017] In some embodiments, the steering control method further includes: controlling the speed of the motor to maintain a set speed when the real-time steering angle is less than or equal to a steering angle threshold.

[0018] A second aspect of this application provides a piece of construction machinery, including a steering cylinder, an electric motor, a steering wheel, and a controller. The steering cylinder is used to drive the construction machinery to steer. The electric motor is drivenly connected to the steering cylinder. The electric motor is signal-connected to the steering wheel to operate when the steering wheel is turned, thereby driving the steering cylinder to actuate. The controller is configured to execute the steering control method described above during the steering of the construction machinery.

[0019] Based on the technical solution provided in this application, the construction machinery includes a steering cylinder, an electric motor, and a steering wheel. The steering cylinder is used to drive the construction machinery to steer. The electric motor is driven by the steering cylinder. The electric motor is signal-connected to the steering wheel to drive the steering cylinder to move when the steering wheel is turned. The steering control method includes the following steps: acquiring the load state of the construction machinery and acquiring the corresponding set speed and initial speed according to the load state, wherein the initial speed is less than the set speed; acquiring the steering wheel movement; and controlling the electric motor to operate at the initial speed when the steering wheel is turned, and controlling the electric motor to operate at the set speed after a set time period. When the operator starts to turn the steering wheel, the electric motor is controlled to operate at a lower initial speed to reduce the impact when the steering cylinder is first started, and also to reduce the impact on the cab, improve steering stability, and optimize the operating experience. Furthermore, after a set time, the electric motor operates at the set speed to ensure the smoothness of the steering process of the construction machinery.

[0020] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0022] Figure 1 This is a flowchart illustrating a steering control method according to some embodiments of this application.

[0023] Figure 2 This is a flowchart illustrating a steering control method according to other embodiments of this application.

[0024] Figure 3 This is a flowchart illustrating a steering control method according to other embodiments of this application. Detailed Implementation

[0025] 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, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0026] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0027] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, and the spatial relative descriptions used herein will be interpreted accordingly.

[0028] First, it should be clarified that the construction machinery in some embodiments of this application includes a front frame and a rear frame rotatably connected to the front frame, and the steering method of the construction machinery is to achieve the steering of the whole vehicle by driving the front frame to swing relative to the rear frame.

[0029] refer to Figure 1 This application provides a steering control method for construction machinery, which includes a steering cylinder, an electric motor, and a steering wheel. The steering cylinder is used to drive the construction machinery to steer. The electric motor is driven by the steering cylinder. The electric motor is signal-connected to the steering wheel to operate when the steering wheel is rotated, thereby driving the steering cylinder to actuate. The steering control method includes the following steps:

[0030] S100: Obtain the load status of the construction machinery and obtain the corresponding set speed and initial speed based on the load status. The initial speed is less than the set speed.

[0031] S200, acquires steering wheel actions; and

[0032] The S300 controls the motor to operate at an initial speed when the steering wheel is turned, and then controls the motor to operate at a set speed after a set time period.

[0033] When the operator begins to turn the steering wheel, the control motor initially operates at a lower speed to reduce the impact when the steering cylinder is first activated, thus reducing the impact on the cab, improving steering stability, and optimizing the driving experience. After a set time, the motor operates at a set speed to ensure smooth steering of the construction machinery.

[0034] Specifically, the construction machinery also includes a steering pump, driven by an electric motor, which is hydraulically connected to the steering cylinder. Changing the electric motor's speed alters the flow rate of the hydraulic oil output from the steering pump, thus regulating the flow of hydraulic oil into the rod chamber of the steering cylinder. This, in turn, controls the cylinder's movement to reduce steering impact. Furthermore, by controlling the electric motor's speed to distribute the flow and pressure of the hydraulic oil to the steering cylinder, the advantages of high efficiency and precise control can be leveraged, improving system efficiency and effectively reducing hydraulic losses.

[0035] In some embodiments, the load state includes no-load, half-load, and full-load. Obtaining the corresponding set speed and initial speed according to the load state includes setting different values ​​for the set speed under different load states. For example, the set speed is set to a first set speed K1 under no-load, a second set speed K2 under half-load, and a third set speed K3 under full-load, where K1 < K2 < K3, and the specific values ​​of K1, K2, and K3 can be set according to the working conditions, without limitation here. By setting different motor speeds according to different load conditions, the motor speed is set faster under full load and slower under no-load. This allows the motor speed to be adapted to the load state of the construction machinery. On the one hand, it reduces the large impact and energy waste caused by the motor operating at a high speed when the construction machinery is under low load; on the other hand, it reduces the problem of uneven steering caused by the motor operating at a low speed when the construction machinery is under heavy load, thus optimizing the steering process of the construction machinery.

[0036] In some embodiments, obtaining the corresponding set speed and initial speed according to the load state includes: making the initial speed different under different load states. For example, the initial speed is set to a first initial speed P1 when unloaded, a second initial speed P2 when half-loaded, and a third initial speed P3 when fully loaded, where P1 < P2 < P3, and the specific values ​​of P1, P2, and P3 can be set according to the working conditions, which is not limited here. By making the motor speed different according to different load conditions, the motor speed is made faster when fully loaded and slower when unloaded. This allows the motor speed to be adapted to the load state of the construction machinery. On the one hand, it reduces the large impact and energy waste caused by the motor operating at a higher speed when the construction machinery is under low load; on the other hand, it reduces the problem of uneven steering caused by the motor operating at a lower speed when the construction machinery is under heavy load, thus optimizing the steering process of the construction machinery.

[0037] In some embodiments, the construction machinery also includes a load cell. The load cell is used to detect the weight of the entire vehicle and thus obtain the load status.

[0038] In other embodiments, the construction machinery also includes tire pressure sensors. The load status is determined by acquiring the tire pressure of the construction machinery through the tire pressure sensors.

[0039] refer to Figure 2 In some embodiments, the steering control method further includes step S401: during the operation of the motor at a set speed, the real-time acceleration of the front frame relative to the rear frame is obtained, and when the real-time acceleration is less than the acceleration threshold, the speed of the motor is controlled to be reduced by a first set value relative to the set speed, so that the speed of the front frame relative to the rear frame is reduced to zero.

[0040] When the real-time acceleration is less than the acceleration threshold, it means that the operator wants to interrupt the steering action of the construction machinery. At this time, the speed of the control motor is reduced by a certain value, and the flow rate of the hydraulic oil output by the steering pump is also reduced by a certain value. Under the influence of factors such as energy loss in the hydraulic oil and friction in the construction machinery, the steering cylinder gradually stops moving, and the steering speed of the front frame relative to the rear frame is reduced to zero, thereby reducing the impact when the steering stops.

[0041] Specifically, a positive acceleration threshold indicates that the acceleration of the front frame relative to the rear frame has decreased compared to the previous moment, indicating the operator intends to interrupt the steering action. A zero acceleration threshold indicates that the speed of the front frame relative to the rear frame has remained unchanged compared to the previous moment, indicating the operator intends to interrupt the steering action. A negative acceleration threshold indicates that the speed of the front frame relative to the rear frame has decreased, indicating the operator intends to interrupt the steering action. In summary, the value of the acceleration threshold affects the sensitivity of the steering process interruption judgment; a positive value will more actively determine that the steering process is about to be interrupted, and the motor speed will be reduced more promptly. The operator can set the acceleration threshold value according to the operating conditions.

[0042] In some embodiments, controlling the motor speed to decrease by a first set value relative to a set speed includes: adjusting the magnitude of the first set value according to the load state, so that the first set value is different under different load states. For example, the first set value is set to a first no-load set value Q11 when unloaded, a first half-load set value Q12 when half-loaded, and a first full-load set value Q13 when fully loaded, where Q11 < Q12 < Q13, and the specific values ​​of Q11, Q12, and Q13 can be set according to the working conditions, which is not limited here. By reducing the motor speed by different amounts depending on the load condition, with a greater reduction under full load and a smaller reduction under no-load, the motor speed can be adapted to the load state of the construction machinery, optimizing the steering process of the construction machinery.

[0043] In some embodiments, when the real-time acceleration is less than an acceleration threshold, the method includes: adjusting the magnitude of the acceleration threshold according to the load state so that the acceleration threshold is different under different load states. For example, the acceleration threshold is set to a first acceleration threshold Acc1 when unloaded, a second acceleration threshold Acc2 when half-loaded, and a third acceleration threshold Acc3 when fully loaded, where Acc1 < Acc2 < Acc3, and the specific values ​​of Acc1, Acc2, and Acc3 can be set according to the working conditions, which is not limited here. This method of making the acceleration threshold correspond to the load state improves the rationality and flexibility of judging the steering interruption state, and further optimizes the steering process of the construction machinery.

[0044] refer to Figure 3In some embodiments, the steering control method further includes step S402: when the real-time acceleration is greater than or equal to an acceleration threshold, controlling the motor speed to maintain a set speed. When the real-time acceleration is greater than or equal to the acceleration threshold, it indicates that the operator's acceleration when turning the steering wheel is large, and the steering is still in the acceleration process, meaning that the operator has not yet wanted to interrupt the steering action of the construction machinery. At this time, maintaining the motor speed ensures the smoothness of the steering process.

[0045] In some embodiments, the steering control method further includes: acquiring the real-time steering angle of the front frame relative to the rear frame while the motor is operating at a set speed; and, if the real-time steering angle is greater than a steering angle threshold, controlling the motor speed to decrease by a second set value relative to the set speed, so that the steering speed of the front frame relative to the rear frame is reduced to zero. The steering angle threshold here is set based on the limit steering angle of the front frame relative to the rear frame, and the steering angle threshold is slightly smaller than the limit steering angle. When the real-time steering angle is greater than the steering angle threshold, it means that the operator is about to turn the steering wheel all the way clockwise or counterclockwise. If the steering wheel is turned all the way directly while the motor maintains a fixed speed, the steering cylinder will extend fully, causing a large impact and posing a risk of damaging the cylinder. Therefore, to reduce this risk, the motor speed is controlled to decrease promptly when the real-time steering angle is detected to be greater than the steering angle threshold.

[0046] In some embodiments, controlling the motor speed to decrease relative to a set speed by a second set value includes: adjusting the magnitude of the second set value according to the load condition, so that the second set value is different under different load conditions. For example, the second set value is set to a first no-load set value Q21 when unloaded, a second half-load set value S22 when half-loaded, and a second full-load set value Q23 when fully loaded, where Q21 < Q22 < Q23, and the specific values ​​of Q21, Q22, and Q23 can be set according to the working conditions, which is not limited here. By reducing the motor speed by different amounts depending on the load condition, the motor speed is reduced more when fully loaded and less when unloaded, thus adapting the motor speed to the load condition of the construction machinery and optimizing the steering process of the construction machinery.

[0047] In some embodiments, the steering control method further includes: maintaining the speed of the electric motor at a set speed when the real-time steering angle is less than or equal to a steering angle threshold. A real-time steering angle less than or equal to the steering angle threshold means that the front frame is still some distance from the limit angle relative to the rear frame; maintaining the speed of the electric motor improves the smoothness of the steering process.

[0048] In some embodiments, the construction machinery also includes an angle sensor. The angle sensor acquires real-time acceleration and real-time rotation angle.

[0049] In some embodiments, the construction machinery also includes a cylinder displacement sensor. The cylinder displacement sensor is used to detect the displacement of the piston rod of the steering cylinder. The real-time steering angle can be obtained by establishing a functional relationship between the piston rod displacement and the angle of rotation of the front frame relative to the rear frame.

[0050] In some embodiments, the construction machinery also includes a directional control valve. The directional control valve is connected to the steering cylinder. When steering begins, steering is interrupted, or the real-time steering angle exceeds a steering angle threshold, the directional control valve actuates to allow a portion of hydraulic oil to enter the rodless chamber of the steering cylinder (the flow rate of this portion of hydraulic oil is less than the flow rate of hydraulic oil entering the rod chamber to ensure that the piston rod can extend smoothly and drive the construction machinery to steer) to apply a reverse force to the piston rod, thereby reducing impact while ensuring no reverse displacement.

[0051] This application also provides a piece of construction machinery, including a steering cylinder, an electric motor, a steering wheel, and a controller. The steering cylinder is used to drive the construction machinery to steer. The electric motor is driven by the steering cylinder. The electric motor is signal-connected to the steering wheel to operate when the steering wheel is turned, thereby driving the steering cylinder to move. The controller is configured to execute the above-described steering control method during the steering process of the construction machinery. The steering process of this construction machinery has low impact and high operating comfort. Furthermore, by controlling the speed of the electric motor to distribute the flow and pressure of the hydraulic oil flowing to the steering cylinder, the advantages of the electric motor's high efficiency and precise control can be utilized, improving system efficiency and effectively reducing hydraulic losses.

[0052] In some embodiments, the construction machinery further includes a power battery pack and a work handle. The controller includes a vehicle controller. The work handle is used to issue work commands. The power battery pack is used to power the electric motor. The steering wheel, work handle, angle sensor, and load cell are all signal-connected to the vehicle controller. The vehicle controller collects various signals to precisely control the electric motor speed. In some embodiments, the construction machinery further includes a motor driver. The motor driver is signal-connected to the electric motor to control the motor's rotation angle and speed.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and not to limit them; although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this application or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of this application, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in this application.

Claims

1. A steering control method for engineering machinery, characterized in that, The construction machinery includes a steering cylinder, an electric motor, a steering wheel, a front frame, and a rear frame rotatably connected to the front frame. The steering cylinder is used to drive the construction machinery to steer. The electric motor is driven by the steering cylinder and signal-connected to the steering wheel to operate when the steering wheel is rotated, thereby driving the steering cylinder to actuate. The steering control method includes the following steps: The load status of the construction machinery is obtained, and a corresponding set speed and initial speed are obtained based on the load status, wherein the initial speed is less than the set speed; The movement of the steering wheel is obtained; as well as When the steering wheel is turned, the motor is controlled to operate at an initial speed and then at a set speed after a set time period. During the operation of the motor at the set speed, the real-time acceleration of the front frame relative to the rear frame is acquired. If the real-time acceleration is less than the acceleration threshold, the speed of the motor is controlled to decrease by a first set value relative to the set speed, so that the speed of the front frame relative to the rear frame is reduced to zero.

2. The steering control method for engineering machinery according to claim 1, characterized in that, The load states include no load, half load, and full load. Obtaining the corresponding set speed and initial speed according to the load states includes: making the value of the set speed different under different load states.

3. The steering control method for engineering machinery according to claim 1, characterized in that, The load states include no load, half load, and full load. Obtaining the corresponding set speed and initial speed according to the load states includes: making the value of the initial speed different under different load states.

4. The steering control method for engineering machinery according to claim 1, characterized in that, The load states include no-load, half-load, and full-load. Controlling the motor speed to decrease by a first set value relative to a set speed includes: adjusting the magnitude of the first set value according to the load state, so that the first set value is different under different load states.

5. The steering control method for engineering machinery according to claim 1, characterized in that, The load states include no load, half load, and full load. When the real-time acceleration is less than the acceleration threshold, the method includes: adjusting the magnitude of the acceleration threshold according to the load state so that the acceleration threshold is different under different load states.

6. The steering control method for engineering machinery according to claim 1, characterized in that, The steering control method further includes: when the real-time acceleration is greater than or equal to the acceleration threshold, controlling the rotational speed of the motor to maintain at the set rotational speed.

7. The steering control method for engineering machinery according to claim 1, characterized in that, The construction machinery includes a front frame and a rear frame rotatably connected to the front frame. The steering control method further includes: during the operation of the motor at a set speed, acquiring the real-time turning angle of the front frame relative to the rear frame; when the real-time turning angle is greater than a turning angle threshold, controlling the speed of the motor to decrease by a second set value relative to the set speed, so that the turning speed of the front frame relative to the rear frame is reduced to zero.

8. The steering control method for engineering machinery according to claim 7, characterized in that, The load states include no-load, half-load, and full-load. Controlling the motor speed to decrease by a second set value relative to a set speed includes: adjusting the magnitude of the second set value according to the load state, so that the second set value is different under different load states.

9. The steering control method for engineering machinery according to claim 7, characterized in that, The steering control method further includes: when the real-time steering angle is less than or equal to a steering angle threshold, controlling the speed of the motor to maintain at the set speed.

10. An engineering machinery, characterized in that, The system includes a steering cylinder, an electric motor, a steering wheel, and a controller. The steering cylinder is used to drive the engineering machinery to steer. The electric motor is drivenly connected to the steering cylinder and signal-connected to the steering wheel to operate when the steering wheel is rotated to drive the steering cylinder to actuate. The controller is configured to perform the steering control method as described in any one of claims 1 to 9 during the steering of the engineering machinery.

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