Land leveler gradient automatic control method and system

Abstract

The invention discloses a land leveler slope automatic control method and system, and belongs to the technical field of engineering machinery slope control, and the system comprises an attitude calibration module, a coordinate acquisition module, a sensor module, a slope calculation module and a hydraulic system module; the attitude calibration module is used for establishing a coordinate system based on the position and attitude of the scraper knife in a vehicle calibration state; and the gradient calculation module is used for calculating the gradient value of the scraper knife in real time according to the rotation angle value of the scraper knife based on each coordinate axis. The method has the beneficial effects that the initial coordinate values of the shovel blade points at the two ends of the shovel blade are calibrated by establishing the three-axis coordinate system, the changes of the roll angle, the pitch angle and the yaw angle of the shovel blade are collected in real time through the sensors, the slope value of the shovel blade is automatically calculated according to the projection of the straight line where the lower edge of the shovel blade is located, and the posture of the shovel blade is corrected according to the target slope value. And the shovel blade keeps an ideal slope for construction operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of engineering machinery slope control, and in particular relates to a grader slope automatic control method and system. Background Art

[0002] As the core equipment of modern earthwork construction, motor graders are widely used in various infrastructure scenarios due to their versatility and high-precision operation capabilities, such as airport construction, highway pavement, and farmland leveling.

[0003] Conventional motor grader construction operations are achieved through operator operation. The operator adjusts the blade movement according to the construction scene and construction tasks, based on his or her own construction experience, so that the blade reaches the desired position for scraping operations. In this traditional manual mode, the blade will change its posture due to the force, and the operator needs to constantly adjust the handle to control the blade. The measures for adjusting the blade are also relatively complicated. The control of the working device includes: changing the posture of the traction frame by adjusting the lifting cylinder and thus changing the height of the blade, changing the posture of the blade by adjusting the inclined pull cylinder, changing the contact area between the blade and the construction surface by adjusting the angle of rotation of the rotating circle, changing the pitch posture of the blade by adjusting the blade thrust cylinder, and changing the scraping surface of the blade by adjusting the blade lead-out cylinder. In general, the movements during the motor grader construction operation are complex, the operation is difficult, and the requirements for technical personnel are high. It is difficult to maintain stable slope operations.

[0004] Currently, some modern technologies use GPS positioning antennas, cameras for image acquisition, or smartphone-assisted measurement methods for slope measurement. These methods are costly, complex to install and use, and lack reliability in grader-operated environments. Therefore, this invention proposes a control method and control system that reduces hardware costs and improves the accuracy of blade contact surface slope calculations. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method and system for automatically controlling the slope of a grader, which can reduce hardware costs and improve the calculation accuracy of the slope of the blade construction contact surface.

[0006] To achieve the above-mentioned objectives, the present invention is implemented by adopting the following technical solutions: a method for automatically controlling the slope of a grader, comprising the following steps: in a vehicle calibration state, establishing a coordinate system based on the position and posture of the shovel blade; obtaining the initial coordinate values ​​of the shovel tips at both ends of the shovel blade in the coordinate system; when the shovel blade posture changes, collecting the rotation angle value of the shovel blade around each coordinate axis in real time; calculating the slope value of the shovel blade in real time based on the rotation angle value of the shovel blade based on each coordinate axis; and adjusting the height of the shovel tips at both ends of the shovel blade in real time based on the initial coordinate values ​​according to the change in the slope value, changing the tilt state of the shovel blade to achieve the target slope value.

[0007] Optionally, the vehicle calibration state refers to a state in which the vehicle is parked on a flat hard ground and the blade and the vehicle body are placed in a vertical posture.

[0008] Optionally, the coordinate system is a three-axis coordinate system consisting of an X-axis, a Y-axis, and a Z-axis, and its establishment method includes taking one of the blade tips at both ends of the blade as the origin, and from the driver's perspective, taking the horizontal direction directly in front of the blade as the X-axis, the horizontal direction of the bottom edge of the blade as the Y-axis, and the vertical upward direction as the Z-axis.

[0009] Optionally, the real-time collection of the rotation angle value of the shovel around each coordinate axis includes using sensors to collect the roll angle, pitch angle and yaw angle of the shovel in real time, the roll angle represents the angle of rotation of the shovel along the X-axis, the pitch angle represents the angle of rotation of the shovel along the Y-axis, and the yaw angle represents the angle of rotation of the shovel along the Z-axis.

[0010] Optionally, the sensor includes a dual-axis inertial navigation sensor and a rotary encoder, the dual-axis inertial navigation sensor is used to collect the roll angle and pitch angle of the blade, and the rotary encoder is used to collect the yaw angle of the blade.

[0011] Optionally, the blade's slope value is calculated in real time based on the blade's rotation angle value based on each coordinate axis, including projecting the blade's posture onto the projection surface in real time in a three-axis coordinate system using the YOZ plane as the projection surface, and calculating the inclination angle of the straight line where the blade's lower edge is located based on the horizontal plane based on the projection image as the blade's slope value.

[0012] Optionally, the blade slope value is calculated in real time based on the rotation angle value of each coordinate axis of the blade, and further includes setting the two tips of the lower edge of the blade to points A and B in the three-axis coordinate system, with coordinates of (X A_bd , Y A_bd , Z A_bd ) and (X B_bd , Y B_bd , Z B_bd ), when the vehicle is calibrated, the elevation difference between points A and B is zero, and the distance between points A and B is Y A_bd and Y B_bd When the blade's roll angle changes alone, the blade's roll angle is equal to the blade's slope value. When the blade's pitch angle changes alone, the blade's slope value is zero. When the blade's yaw angle changes alone, the blade's slope value is zero.

[0013] When multiple blade inclination angles change at the same time, according to the coordinate system setting and the definition of the rotation direction, the corresponding space rotation matrix is ​​selected for analytical calculation to calculate the elevation difference Z between the two blade tips after the change. AB and the projection length Y of line segment AB on the Y axisAB , and then the slope value of the blade is solved through trigonometric functions.

[0014] Optionally, the roll angle, pitch angle, yaw angle and corresponding slope value of the shovel are displayed in real time on the human-computer interaction screen. The target slope value is set through interactive operation, and the height of the shovel tips at both ends of the shovel are adjusted.

[0015] A grader automatic slope control system includes: a posture calibration module, a coordinate acquisition module, a sensor module, a slope calculation module, and a hydraulic system module; the posture calibration module is used to establish a coordinate system based on the position and posture of a shovel blade when the vehicle is in a calibration state; the coordinate acquisition module is used to obtain the initial coordinate values ​​of the blade tips at both ends of the blade in the coordinate system; the sensor module is used to collect the rotation angle value of the blade around each coordinate axis in real time when the blade posture changes; the slope calculation module is used to calculate the blade slope value in real time based on the blade rotation angle value around each coordinate axis; the hydraulic system module is used to adjust the height of the blade tips at both ends of the blade in real time according to the change in the slope value, changing the blade tilt state to achieve the target slope value.

[0016] Optionally, the slope calculation module is used to project the posture of the shovel onto the projection surface in real time in a three-axis coordinate system with the YOZ plane as the projection surface, and calculate the inclination angle of the straight line where the lower edge of the shovel is located based on the horizontal plane according to the projection image as the slope value of the shovel.

[0017] Compared with the prior art, the present invention has the following beneficial effects: By establishing a three-axis coordinate system and calibrating the initial coordinate values ​​of the blade tips at both ends of the blade, sensors are used to collect changes in the blade's roll angle, pitch angle, and yaw angle in real time. The blade's slope value is automatically calculated based on the projection of the straight line on which the lower edge of the blade lies. The blade's posture is corrected according to the target slope value, allowing the blade to maintain an ideal slope for construction operations.

[0018] The automatic grader slope control system of the present invention can share some hardware equipment with the vehicle system, and only a small amount of additional hardware needs to be installed to form the system. The device cost is low, the installation is convenient, the system is stable and reliable, and it has high slope control accuracy.

[0019] Compared with the traditional earth-moving machinery grader leveling and slope scraping operation method, the present invention reduces the construction errors caused by human factors and has higher slope automatic control accuracy. Compared with some modern slope determination technologies, it eliminates the installation of hardware such as positioning antennas and cameras, and has the advantages of low cost, easy use, safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Shown is a hardware connection diagram of the present invention; Figure 2 Shown is a side view of the motor grader of the present invention; Figure 3 Shown is a coordinate diagram of the blade tip of the motor grader of the present invention; Figure 4 Shown is a front view of the motor grader of the present invention; Figure 5 Shown is a schematic diagram of a simplified model of the scraper blade body of the present invention; Figure 6 Shown is a front view of the roll angle of the rectangular model of the scraper blade of the present invention; Figure 7 Shown is a side view of the roll angle of the rectangular model of the scraper blade of the present invention; Figure 8 Shown is a front elevation view of a rectangular model of a shovel blade according to the present invention; Figure 9 Shown is a side view of a rectangular model of a shovel blade according to the present invention at a pitch angle; Figure 10 Shown is a front view of the yaw angle of the rectangular model of the scraper blade of the present invention; Figure 11 Shown is a side view of the yaw angle of the rectangular model of the blade of the present invention; Figure 12 The figure shows the combined angle variation diagram of the rectangular model of the scraper blade of the present invention; Figure 13 Shown is a flow chart of the automatic slope control method for a motor grader according to the present invention.

[0021] In the figure: 1. Rear slack; 2. Cab; 3. Lifting cylinder; 4. Front frame; 5. Traction frame; 6. Front shovel; 7. Shovel angle; 8. Side shift cylinder; 9. Shovel blade; 10. Rotating circle; 11. Right shovel tip; 12. Left shovel tip; 13. Right rectangular corner; 14. Left rectangular corner; 15. Right endpoint; 16. Left endpoint. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0023] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0024] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances. Example 1

[0025] This embodiment provides a method for automatically controlling the slope of a grader, which specifically includes the following steps: Step 1: In the vehicle calibration state, establish a coordinate system based on the position and posture of the blade; Step 2: Obtain the initial coordinate values ​​of the blade tips at both ends of the blade in the coordinate system; Step 3: When the blade posture changes, the rotation angle value of the blade around each coordinate axis is collected in real time; Step 4: Calculate the blade's slope value in real time based on the blade's rotation angle value based on each coordinate axis; Step 5: According to the change of the slope value, based on the initial coordinate value, the height of the blade tips at both ends of the blade is adjusted in real time to change the blade tilt state to achieve the target slope value.

[0026] The vehicle calibration state refers to the vehicle being parked on a flat, hard surface with the blade perpendicular to the vehicle body. A three-axis coordinate system consisting of the X, Y, and Z axes is established, using one of the blade tips as the origin. From the driver's perspective, the X-axis is the horizontal direction directly in front of the blade, the Y-axis is the horizontal direction along the bottom edge of the blade, and the Z-axis is the vertically upward direction.

[0027] The vehicle calibration state is to obtain the mechanical key point information of the shovel blade body 9 itself. The vehicle body posture used is for auxiliary reference. The spatial structural relationship of the shovel blade body 9 is obtained through calibration. The vertical posture placement means that the longitudinal axis of the vehicle body is perpendicular to the horizontal axis of the shovel blade.

[0028] To determine the calibration status of the vehicle, the distance from the upper edge of the shovel to the ball joint of the traction frame 5 can be measured with a ruler, so that the upper edges of the left and right shovels are equal to the left and right sides of the ball joint, and the displacement of the left and right lifting cylinders 3 can be measured with a ruler to be equal; the total station can also be used to assist in measurement. By taking point information, two points on the shovel and the vehicle body are taken respectively to determine the axial direction of the shovel and the vehicle body, and then determine whether the shovel posture and the vehicle body posture are placed vertically.

[0029] The position and direction sequence of each axis of the coordinate system satisfies the right-hand rule. From the driver's perspective, the Y-axis can be determined to be horizontal and facing left. A projection reference coordinate system is also established, with the forward direction as the coordinate system's X-axis and the vertically upward direction as the coordinate system's Z-axis. According to the right-hand rule, the Y-axis can be determined to be horizontal and facing left. The YOZ plane of the projection reference system is the projection plane, and the blade slope is the inclination angle of the blade's lower operating edge projected on the YOZ plane. Example 2

[0030] This embodiment provides a method for automatically controlling the slope of a grader, further comprising the following steps: using sensors to collect the roll angle, pitch angle, and yaw angle of the blade in real time, where the roll angle represents the angle of rotation of the blade along the X-axis, the pitch angle represents the angle of rotation of the blade along the Y-axis, and the yaw angle represents the angle of rotation of the blade along the Z-axis.

[0031] The sensor includes a dual-axis inertial navigation sensor and a rotary encoder. The dual-axis inertial navigation sensor is used to collect the roll angle and pitch angle of the shovel blade, and the rotary encoder is used to collect the yaw angle of the shovel blade.

[0032] The blade's slope value is calculated in real time based on the blade's rotation angle value based on each coordinate axis. This includes projecting the blade's posture onto the projection surface in real time in a three-axis coordinate system using the YOZ plane as the projection surface. The inclination angle of the straight line where the blade's lower edge is located based on the horizontal plane is calculated based on the projection image as the blade's slope value.

[0033] The blade slope value is calculated in real time based on the blade rotation angle value based on each coordinate axis. In addition, the two tips of the lower edge of the blade are set as points A and B in the three-axis coordinate system, and the coordinates are (X A_bd , Y A_bd , Z A_bd ) and (X B_bd , Y B_bd , Z B_bd), when the vehicle is calibrated, the elevation difference between points A and B is zero, and the distance between points A and B is Y A_bd and Y B_bd When the blade's roll angle changes alone, the blade's roll angle is equal to the blade's slope value. When the blade's pitch angle changes alone, the blade's slope value is zero. When the blade's yaw angle changes alone, the blade's slope value is zero.

[0034] When multiple blade inclination angles change at the same time, due to the coupling relationship between the roll angle, pitch angle, and yaw angle in space, it is necessary to select the corresponding spatial rotation matrix for analytical calculation based on the coordinate system setting and rotation direction definition to calculate the elevation difference Z between the two blade tips after the change. AB and the projection length Y of line segment AB on the Y axis AB , and then the slope value of the blade is solved through trigonometric functions.

[0035] The blade's roll angle, pitch angle, yaw angle and corresponding slope value are displayed in real time on the human-computer interaction screen. The target slope value can be set through interactive operations and the height of the blade tips at both ends of the blade can be adjusted.

[0036] like Figure 3 As shown, when the shovel is in the calibrated posture, the shovel is viewed from the front of the vehicle as the main view, and the shovel is viewed from the driver's right hand as the side view to illustrate the slope changes at different inclination angles.

[0037] The model of the blade body 9 is simplified, as shown in the following example: Figure 4 and Figure 5 As shown, the positional relationship between the right shovel tip 11 and the left shovel tip 12 is the focus of the present invention. The blade model can be simplified into a rectangle, and then the right shovel tip 11 and the left shovel tip 12 are simplified into the right rectangular corner 13 and the left rectangular corner 14 respectively. The key point of the study in the rectangle is the lower edge of the blade operation, so the lower edge of the blade can be simplified into a straight line, and the right endpoint 15 and the left endpoint 16 are the right shovel tip 11 and the left shovel tip 12.

[0038] The blade undergoes a single tilt angle change based on the calibration posture. When this single angle is the roll angle, Figure 6 and Figure 7 As shown, the blade rotates around the X-axis or in a direction parallel to the X-axis and stops when it rotates to a certain angle. When viewing the blade from this perspective, that is, from the projection of the blade in the direction directly in front of the vehicle, the blade's roll angle is equal to the blade's slope value.

[0039] The blade undergoes a single tilt angle change based on the calibration posture. When this single angle is the pitch angle, such as Figure 8 and Figure 9As shown, the blade rotates around the Y-axis or in a direction parallel to the Y-axis and stops when it rotates to a certain angle. When viewing the blade from this perspective, that is, from the projection of the blade in the direction directly in front of the vehicle, the blade's roll angle is equal to the blade's slope value, and the blade's pitch angle changes based on the calibrated posture, and the blade's slope value is zero.

[0040] The blade undergoes a single tilt angle change based on the calibration posture. When this single angle is the yaw angle, such as Figure 10 and Figure 11 As shown, the blade rotates around the X-axis or in a direction parallel to the X-axis and stops when it rotates to a certain angle. When viewing the blade from this perspective, that is, from the projection of the blade in the direction directly in front of the vehicle, the blade's roll angle is equal to the blade's slope value, and the blade's slope value is zero when the yaw angle changes based on the calibration posture.

[0041] The blade undergoes multiple inclination angle changes based on the calibration posture. There are multiple options for the order of free combination of the three direction angles, corresponding to multiple results. Here we only take the angle change order of roll, yaw, and pitch as an example. Figure 12 As shown, when the roll angle changes from the calibration state to state 1, which is consistent with the single tilt angle change, the blade's roll angle is equal to the blade's slope value when projected toward the front of the vehicle.

[0042] In state one, the yaw angle changes to reach state two. During this conversion process, the positions of the left and right tips of the shovel rotate and change, but the height remains unchanged. It can be seen that the height difference between the two shovel tips also remains unchanged. At the same time, the projection length of the lower edge of the shovel working surface on the Y-axis is getting smaller, and the trend of change is from maximum to minimum and then to maximum. The slope value can be deduced from the elevation and the size ratio relationship of the projection of line segment AB on the Y-axis. At this time, the change of multiple angle combinations is different from the change of a single yaw angle.

[0043] In state two, the pitch angle changes to reach state three. During this conversion process, the projection difference between the left and right shovel tips on the Y-axis remains unchanged, and the elevation of one of the two shovel tips becomes larger and the other becomes smaller. The specific larger and smaller one can be judged based on the positive and negative signs of the pitch rotation angle. The elevation difference between the two shovel tips becomes smaller, and the slope value can also be derived from the elevation and the size ratio relationship of the projection of line segment AB on the Y-axis. At this time, the slope value of the shovel blade under the condition of multiple angle combination changes is different from the slope value under the condition of a single pitch angle change.

[0044] Use the mobile station to calibrate the coordinates of the tips of both ends of the shovel. From the driver's perspective, record the right shovel tip as point A and the left shovel tip as point B. By calibrating the position information of the two shovel tips, the spatial dimensions of the lower operating edge of the shovel body can be determined.

[0045] The roll angle and pitch angle are read and analyzed from the inertial navigation sensor, and the yaw angle is read and analyzed from the rotary encoder. The rotary encoder selectively performs initial angle calibration and correction on itself according to its own characteristics. The data storage controller facilitates the call of the slope algorithm.

[0046] Calibrate the inertial sensor angle value and the rotary encoder angle value, input and store them into the controller. The sensor can use three single-axis sensors or one three-axis sensor to ensure that the collected angle data and direction are consistent.

[0047] Set the target construction slope value on the human-computer interaction screen. This slope value serves as the baseline for construction operations. This setting forces the blade to approach the target value. Slope values ​​can be expressed in two ways: as an angle in degrees or as a percentage, which is the trigonometric function Tan angle magnified 100 times and expressed in gradians. These two expressions define the slope differently, but they refer to the same slope. After setting the slope value according to the construction standards, save the settings for easy use in subsequent calculations.

[0048] Turn on the first-level automatic control function switch of the slope control on the human-machine interaction screen. In order to ensure the safety of earth-moving machinery construction operations and prevent the slope control system from taking effect when the slope difference increases, it is in the off state in the normal operation scenario of the grader. It only needs to be turned on when the slope requires automatic control. After turning it on, the slope automatic control and manual control exist at the same time. The manual operation control has a higher priority, which also ensures that the operator's operation instructions have a higher priority. After the slope automatic control function is turned on, there will be an icon prompt on the human-machine interaction screen. The first-level automatic control function switch, as the main switch of the slope automatic control function, has pattern recognition and safety protection functions. The switch button can rely on the software button of the human-machine interaction screen, or it can be an external rocker switch mechanical button on the device of the present invention.

[0049] During the construction process of the grader, the system collects data from the inertial navigation sensor and rotary encoder in real time. This means that the posture of the vehicle body and the blade changes due to factors such as terrain and force during the construction process. The inertial navigation sensor and rotary encoder record data information in real time. The positions of the right shovel tip 11 and the left shovel tip 12 follow the changes in the blade posture. The real-time slope value is calculated by projection on the blade coordinate system. This slope value indicates the slope formed by the blade scraping the soil when the grader is constructing in the current posture, and it is not necessarily the ideal target slope.

[0050] The simplified blade model is a line segment formed by the right endpoint 15 and the left endpoint 16. During the construction process, any spatial angular change in the blade can be simplified as a change in the spatial posture of the blade's lower edge. When the lift cylinder 3 and the inclined pull cylinder change the posture of the traction frame 5, the blade body undergoes spatial posture changes, causing the blade to deflect in roll, pitch, and yaw. This is equivalent to the roll, pitch, and yaw changes of a line in three-dimensional space. As the blade body's spatial posture changes, angular information is collected in real time. The real-time angle values ​​at any moment can be expressed as the real-time roll angle θ, real-time pitch angle α, and real-time yaw angle β. Based on the calibrated angle values, the angular differences of the blade body about the X, Y, and Z axes are calculated. This allows the projection line of the simplified model line on the YOZ plane of the projection reference system to be determined. The inclination angle of this projection line represents the slope formed by the blade contacting the ground during operation, thus obtaining the real-time calculated slope value.

[0051] In order to prevent erroneous operation and information input errors, a threshold range is set for the slope difference. When the absolute value of the elevation difference exceeds the threshold range, the controller sends information to the human-computer interaction screen, indicating that the slope difference is abnormal, suspends the automatic slope control function, and waits for the operator's confirmation.

[0052] The calculated slope value can be expressed in two forms: angle and percentage. The angle is the inverse trigonometric function ArcTan of the inclined line, while the percentage angle is the trigonometric function Tan multiplied by 100.

[0053] The calculated slope value is displayed on the interface. The slope difference, to a certain extent, indicates the required blade adjustment, serving as a user guide. Furthermore, the slope difference serves as the basis for controlling blade movement. This slope difference is calculated based on the established baseline slope value and the calculated real-time slope value. The slope difference can be calculated by subtracting the baseline slope from the baseline slope, or vice versa, depending on the definition of left-right slope. This example assumes that a positive slope is higher on the left and lower on the right, while a negative slope is lower on the left and higher on the right. Once the left-right slope definition is agreed upon, the calculated slope difference is processed as input by the control program. Based on the sign and absolute value of the input, logic control is performed, and the hydraulic valve group controls the corresponding cylinder movements, thereby driving the blade movement and changing the blade's slope attitude. Blade control requirements include fast response, smooth and seamless control curves, and a standard slope on the blade contact surface.

[0054] For safety reasons and to prevent misoperation and incorrect input, a threshold range is set for the grade difference. When the absolute value of the grade difference falls within this threshold, the controller sends a command to the hydraulic system valve to control the cylinder. When the absolute value of the elevation difference exceeds this threshold, the controller sends a message to the human-machine interface, indicating that the grade difference is abnormal and suspending the automatic grade control function.

[0055] Selectively turn on or off the secondary left and right automatic control function. The left automatic control adjusts the lifting of the left cylinder to control the height of the left blade; the right automatic control adjusts the lifting of the right cylinder to control the height of the right blade. In the example, it is assumed that the left automatic control is turned on and the right automatic control is turned off. When there is a slope difference in the blade, the controller will adjust the left lifting cylinder 3, change the height of the left blade tip, no longer control the right lifting cylinder 3, and fix the lifting of the right blade to eliminate the slope difference and achieve the target slope. The secondary left and right automatic control function means that the slope control system can control the left lifting cylinder 3 separately, the right lifting cylinder 3 separately, and the lifting cylinders 3 on both sides at the same time, further realizing more refined control.

[0056] The direction and movement speed of the cylinder control are affected by the slope difference. The positive or negative slope difference affects the selection and lifting decision of the shovel, and the absolute value of the slope difference affects the movement speed decision of the shovel. Example 3

[0057] This embodiment provides an automatic slope control system for a motor grader, comprising: a posture calibration module, a coordinate acquisition module, a sensor module, a slope calculation module, and a hydraulic system module; the posture calibration module is configured to establish a coordinate system based on the position and posture of a shovel blade when the vehicle is in a calibration state; the coordinate acquisition module is configured to obtain the initial coordinate values ​​of the blade tips at both ends of the blade in the coordinate system; the sensor module is configured to collect the rotation angle values ​​of the blade around each coordinate axis in real time when the blade posture changes; the slope calculation module is configured to calculate the blade slope value in real time based on the blade rotation angle values ​​around each coordinate axis; and the hydraulic system module is configured to adjust the height of the blade tips at both ends of the blade in real time based on changes in the slope value, thereby changing the blade tilt state to achieve a target slope value.

[0058] The slope calculation module is used to project the blade's posture onto the projection surface in real time in a three-axis coordinate system with the YOZ plane as the projection surface. The inclination angle of the straight line where the lower edge of the blade is located based on the horizontal plane is calculated based on the projection image as the blade's slope value.

[0059] like Figure 1As shown in the figure, the control system is installed on the grader earth-moving machinery and is used to adjust the position of the grader blade. It includes an on-board power supply, a controller, a human-machine interaction screen, a hydraulic system, a cylinder, a working blade, an inertial navigation sensor and a rotary encoder. The hydraulic system, the cylinder and the working blade are important actuators.

[0060] like Figure 2 As shown, the mechanical structural parts of the grader body include a rear sprocket 1, a cab 2, a lifting cylinder 3, a front frame 4, a traction frame 5, a front shovel 6, a shovel angle 7, a side shift cylinder 8, a shovel blade body 9, and a rotating circle 10.

[0061] During the construction process of the grader, the blade body 9 will change its posture due to the influence of various factors, including the ups and downs of the construction surface, the lifting and tilting of the traction frame 5, the turning change of the rotating circle 10, the up and down swing of the scraping angle 7, and the change of the extension stroke of the side shift cylinder 8.

[0062] The vehicle-mounted power supply is installed in the cab 2 , the oil cylinder specifically refers to the lifting oil cylinder 3 , and the working blade is the basic working component of the grader earthmoving equipment.

[0063] The controller is powered by the vehicle's power supply and connected to the HMI screen, inertial navigation sensor, and rotary encoder via a wiring harness, enabling power supply and CAN line data exchange. The controller, equipped with data parsing, storage, calculation, and interaction capabilities, is installed inside the grader's cab 2. It analyzes data from the inertial navigation sensor and rotary encoder, stores calibrated angle and coordinate data, calculates blade slope in real time, and transmits the results to the HMI screen.

[0064] The HMI screen is installed in the cab 2, slightly below and directly in front of the driver. This allows for easy data viewing while maintaining a wide field of vision. The screen allows for input, modification, and viewing of data. System parameters can be modified and viewed via physical buttons and the touchscreen. In addition to conventional display functions, the screen also allows for setting slopes by entering numerical values ​​and displays blade attitude slopes in real time, both numerically and graphically.

[0065] The hydraulic system is installed below the cab 2 and is used to receive controller instructions and control the corresponding cylinder movements. The lifting cylinder 3, as an important component of the grader vehicle, has a simple structure and reliable operation. It is a key actuator for controlling the operation of the shovel blade. The shovel blade body 9 is an important controlled object of the present invention and is also the most basic working part of the grader. A series of leveling and slope scraping operations of the grader cannot be separated from the shovel blade body 9.

[0066] The inertial navigation sensor itself has a gravity reference system and is equipped with an inclination reference axis. It can measure the angle value when it rotates around the X-axis and Y-axis. The inertial navigation sensor is horizontally installed on the shovel blade to measure the angle of the shovel blade in space. The sensor installation position is parallel to the main axis direction of the shovel blade as a whole in space, and the sensor installation contact surface is tightly fitted with the shovel blade body 9 to ensure that the angle data measured by the inertial navigation sensor is the change data of the shovel blade body 9. The inertial navigation sensor can be used in combination and is not limited to single-axis, dual-axis, and three-axis sensors.

[0067] There are certain requirements for the installation position and direction of the inertial navigation sensor. The installation position is on the plane of the scraper body 9, and mechanical interference during the scraper movement is avoided. The installation direction is horizontal, and the longitudinal and transverse axes are kept horizontal with the longitudinal and transverse axes of the scraper body 9. When the inertial navigation sensor adopts dual-axis, a rotary encoder needs to be installed.

[0068] The rotary encoder is installed on the central axis of the rotating circle 10, and the bottom mounting seat of the rotary encoder is tightly fitted with the central axis of the rotating circle 10 to ensure coaxial and concentric rotation. It is used to measure the angle change of the rotating circle 10, and angle calibration is required after installation.

[0069] The rotary encoder is mounted on the rotary circle 10 of the grader working device, and its bottom is fixed on the rotating shaft of the rotary circle 10. If a three-axis inertial navigation sensor is used, the rotary encoder can be omitted.

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for automatically controlling the slope of a grader, characterized in that: The following steps are involved: In the vehicle calibration state, a coordinate system is established based on the position and posture of the blade; Get the initial coordinate values ​​of the blade tips at both ends of the blade in the coordinate system; When the blade posture changes, the rotation angle value of the blade around each coordinate axis is collected in real time; Calculate the blade's slope value in real time based on the blade's rotation angle value based on each coordinate axis; According to the change of the slope value, based on the initial coordinate value, the height of the blade tips at both ends of the blade is adjusted in real time to change the tilt state of the blade to achieve the target slope value.

2. The automatic slope control method for a motor grader according to claim 1, characterized in that: The vehicle calibration state refers to a state in which the vehicle is parked on a flat hard surface and the blade and the vehicle body are placed in a vertical position.

3. The automatic slope control method for a motor grader according to claim 1, characterized in that: The coordinate system is a three-axis coordinate system consisting of the X-axis, Y-axis and Z-axis. The establishment method includes taking one of the blade tips at both ends of the blade as the origin, and from the driver's perspective, taking the horizontal direction directly in front of the blade as the X-axis, the horizontal direction of the bottom edge of the blade as the Y-axis, and the vertical upward direction as the Z-axis.

4. The automatic slope control method for a motor grader according to claim 3, characterized in that: The real-time acquisition of the rotation angle value of the blade around each coordinate axis includes: The sensors are used to collect the roll angle, pitch angle and yaw angle of the shovel in real time. The roll angle represents the angle of rotation of the shovel along the X-axis, the pitch angle represents the angle of rotation of the shovel along the Y-axis, and the yaw angle represents the angle of rotation of the shovel along the Z-axis.

5. The automatic slope control method for a motor grader according to claim 4, characterized in that: The sensor includes a dual-axis inertial navigation sensor and a rotary encoder. The dual-axis inertial navigation sensor is used to collect the roll angle and pitch angle of the blade, and the rotary encoder is used to collect the yaw angle of the blade.

6. The automatic slope control method for a motor grader according to claim 4, characterized in that: The method calculates the slope value of the shovel in real time based on the rotation angle value of the shovel based on each coordinate axis, including using the YOZ plane as the projection plane in the three-axis coordinate system, projecting the posture of the shovel onto the projection plane in real time, and calculating the inclination angle of the straight line where the lower edge of the shovel is located based on the horizontal plane according to the projection image as the slope value of the shovel.

7. The automatic slope control method for a motor grader according to claim 6, characterized in that: The method of calculating the slope value of the blade in real time based on the rotation angle value of each coordinate axis of the blade also includes setting the two tips of the lower edge of the blade as points A and B in the three-axis coordinate system, with coordinates of (X A_bd , Y A_bd , Z A_bd ) and (X B_bd , Y B_bd , Z B_bd ), when the vehicle is calibrated, the elevation difference between points A and B is zero, and the distance between points A and B is Y A_bd and Y B_bd When the blade's roll angle changes alone, the blade's roll angle is equal to the blade's slope value. When the blade's pitch angle changes alone, the blade's slope value is zero. When the blade's yaw angle changes alone, the blade's slope value is zero. When multiple blade inclination angles change at the same time, according to the coordinate system setting and the definition of the rotation direction, the corresponding space rotation matrix is ​​selected for analytical calculation to calculate the elevation difference Z between the two blade tips after the change. AB and the projection length Y of line segment AB on the Y axis AB , and then the slope value of the blade is solved through trigonometric functions.

8. The automatic slope control method for a motor grader according to claim 4, characterized in that: The blade's roll angle, pitch angle, yaw angle and corresponding slope value are displayed in real time on the human-computer interaction screen. The target slope value can be set through interactive operations and the height of the blade tips at both ends of the blade can be adjusted.

9. A grader slope automatic control system, using the control method according to any one of claims 1 to 7, characterized in that: include: The posture calibration module is used to establish a coordinate system based on the position and posture of the blade in the vehicle calibration state; A coordinate acquisition module is used to obtain the initial coordinate values ​​of the blade tips at both ends of the blade in the coordinate system; The sensor module is used to collect the rotation angle value of the blade around each coordinate axis in real time when the blade posture changes; The slope calculation module is used to calculate the slope value of the shovel in real time according to the rotation angle value of the shovel based on each coordinate axis; The hydraulic system module is used to adjust the height of the blade tips at both ends of the blade in real time according to the changes in the slope value, change the tilt state of the blade to achieve the target slope value.

10. The automatic slope control system for a motor grader according to claim 9, characterized in that: The slope calculation module is used to project the blade's posture onto the projection surface in real time in a three-axis coordinate system with the YOZ plane as the projection surface, and calculate the inclination angle of the straight line where the lower edge of the blade is located based on the horizontal plane according to the projection image as the slope value of the blade.

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