Path tracking control method for central hinge type carry-scraper

Abstract

The invention provides a path tracking control method for a central hinge type carry-scraper, relates to the technical field of vehicle control, and effectively solves the problems of inherent strong nonlinearity and relatively large time delay of a hydraulic steering system by introducing a nonlinear adjustment mechanism. According to the method, the preview distance can be adaptively adjusted according to the real-time state of the center hinge type carry-scraper, and the nonlinear and hysteresis effects brought by a hydraulic system are compensated, so that the path tracking precision and the robustness of the whole system are remarkably improved. By adopting the self-adaptive preview distance, the feedback error can be calculated in real time, and the feedback error is processed by the nonlinear feedback error controller to generate actual control input. Compared with a traditional control method based on feedback errors, the method is more stable in performance under the dynamically changing working condition, the control precision is higher, and the path tracking precision of the carry-scraper under the complex working condition is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle control, and particularly to a path tracking control method for a center hinge type scraper loader. Background Art

[0002] With the continuous development of trackless mining technology, the hydraulic center articulated scraper loader, as the core equipment for underground operations, plays a crucial role. Its center articulated structure exhibits higher mobility and flexibility compared to traditional fixed-frame center hinge type scraper loaders, enabling efficient operation in narrow and complex underground mining environments. Along with the development of technologies such as sensors and intelligent control, underground scraper loaders are gradually achieving intelligence, but there are still huge challenges in their autonomous driving technology. The performance of the hydraulic system is limited by factors such as the inertia of hydraulic oil flow, the mechanical inertia of hydraulic cylinders and motors, the compressibility of hydraulic fluids, and the transmission delay in pipelines.

[0003] The above factors make it difficult to accurately model the hydraulic system, thus affecting its adaptability to external disturbances and further having an adverse impact on path tracking accuracy. Therefore, the existing model-based automatic control methods show obvious limitations in practical applications. The underground mine operation environment is narrow, posing higher requirements for the accuracy and stability of path tracking control. Moreover, working conditions such as complex road conditions and changing loads further exacerbate the control difficulty, becoming the main obstacle restricting the autonomous and intelligent development of scraper loaders in actual scenarios.

[0004] The control methods based on the center hinge type scraper loader model and feedback error have been widely used to solve the path tracking nonlinear control problem of hydraulic-driven center articulated scraper loaders, but the effectiveness of these research results in practical applications is still significantly limited. Especially, the hysteresis effect and large inertia of the hydraulic system pose great challenges to the practical application of these methods. The existing control methods based on the center hinge type scraper loader model mostly focus on simulation environments or scaled-down demonstration center hinge type scraper loaders, and their control effects have not been fully verified in the actual working environment of scraper loaders; while the traditional feedback error-based methods cannot provide sufficient accuracy and adaptability when facing dynamically changing loads, speeds, and working states, restricting their application effects in the control of complex center hinge type scraper loaders such as hydraulic-driven center articulated scraper loaders. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to propose a path tracking control method for a center hinge type scraper loader, including: Step 1: Collect the status information of the center hinge type scraper through the vehicle-mounted sensors configured on the center hinge type scraper. The status information includes speed, front wheel center pose, and rear wheel center pose. The vehicle-mounted sensors transmit the status information to the main controller; Step 2: In the main controller, determine the current status of the center hinge type scraper. The current status is expressed as: ; where, x is the abscissa of the reference status position G ; y is the ordinate of the reference status position G ; is the orientation angle; is the articulation angle; Step 3: Obtain the reference path RP , and the reference path RP is composed of multiple discrete points. The points on the reference path are expressed as: ; where, represents the point on the reference path, u is the reference path parameter, is 's abscissa, is 's ordinate, U is the domain of the path parameter; Step 4: On the reference path RP , determine the reference path point G corresponding to the reference status position , where, is the abscissa of the reference path point , is the ordinate of the reference path point , is the path parameter of the reference path point ; Step 5: Calculate the Euclidean distance between the reference status position G and the reference path point . Take the Euclidean distance between the reference status position G and the reference path point as the lateral error , which is specifically implemented through the following formula: ; Step 6: Based on the speed v and the lateral error , dynamically adjust the preview distance, and then determine the preview point L , and the preview pointL Among all points on the reference path, the point at a preview distance from the reference state position G The reference state position G Points to the preview point L The direction is the preview direction; Step 7: Obtain the desired state of the center hinge type scraper The desired state Is expressed as: ; Among them, Represents the desired articulation angle, which is the articulation angle corresponding to when the instantaneous desired path of the center hinge type scraper can pass through the preview point; Step 8: Calculate the included angle between the current movement direction and the preview direction of the center hinge type scraper And then calculate the component of the desired state articulation angle Component ; Step 9: Calculate the relationship between the articulation angle and the telescopic amount of the hydraulic cylinder And then calculate the feedback error ; Step 10: According to the feedback error , calculate the proportional term , integral term And non-linear differential term Of the controller, and then calculate the output signal Of the controller, the output signal Of the controller is used to adjust the opening of the steering valve in the hydraulic system.

[0006] Optionally, step 2 specifically includes: In the main controller, according to the traveling state of the center hinge type scraper, select one of the front wheel center pose and the rear wheel center pose as the target center pose, the target center pose determines the reference state position and the orientation angle , according to the front wheel center pose and the rear wheel center pose, determine the articulation angle , the articulation angle Is the relative rotation angle between the front and rear car bodies of the center hinge type scraper, the reference state position, the orientation angle And the articulation angle Constitute the current state.

[0007] Optionally, step 4 specifically includes: Taking the reference path point As an unknown parameter, calculate the tangent vector Of the reference path point , The component of is expressed as: ; ; Among them, represents the first derivative of, represents the first derivative of; Based on the reference state position G and the tangent vector , construct the tangent equation, and the tangent equation is expressed as: ; Among them, is the tangent vector at the reference path point ; Solve the tangent equation to obtain the solution set , in the case of the solution set , select the point closest to the reference state position G from the solution set as the reference path point , in the case of the solution set , then select the point closest to the reference state position on the reference path G as the reference path point .

[0008] Optionally, in step 6, based on the speed v and the lateral error , dynamically adjust the preview distance, which is specifically implemented by the following formula: ; Among them, represents the preview distance, is used to adjust the sensitivity of the preview distance change, represents the influence degree on the preview distance, represents the hinge angle the influence degree on the preview distance.

[0009] Optionally, step 8 specifically includes: Calculate the included angle between the current movement direction of the vehicle and the preview direction, which is specifically implemented by the following formula: ; Among them, is the y-component of the coordinate G of the reference state position, is the coordinate G of the reference state position x component, is the reference state position G toward angle component; Since the value of the instantaneous turning radius is the magnitude of the turning radius of the vehicle in front, a geometric equation is constructed based on geometric relationships, and the geometric equation is expressed as: ; wherein, is the length of the front body of the center hinge type scraper, is the length of the rear body of the center hinge type scraper, is the desired state articulation angle component; The desired state articulation angle component .

[0010] Optionally, step 9 specifically includes: Calculate the relationship between the articulation angle and the telescopic amount of the hydraulic cylinder , which is specifically implemented through the following formula: ; wherein, is the length from the articulation point to the first connection point, and the first connection point is the connection point between the hydraulic cylinder and the front body, is the length from the articulation point to the second connection point, and the second connection point is the connection point between the hydraulic cylinder and the rear body, is the initial length of the hydraulic cylinder; Based on the relationship between the articulation angle and the telescopic amount of the hydraulic cylinder , calculate the feedback error , which is specifically expressed by the following formula: ; wherein, is the physical limit of the hinge angle.

[0011] Optionally, step 10 specifically includes: Step 10.1: According to the feedback error , calculate the proportional term of the controller, which is specifically implemented through the following formula: ; wherein, is the proportional gain coefficient, is the saturation value of the proportional term, is the sign function; Step 10.2: According to the feedback error , calculate the integral term in the controller, which is specifically implemented through the following formula: ; Among them, is the integral gain coefficient, is the saturation value of the integral term of Step 10.3: According to the differential of the feedback error , calculate the non-linear differential term of the controller, which is specifically implemented by the following formula: ; Among them, is the differential gain coefficient, is the magnification factor, is the feedback error is the differential of Step 10.4: Based on the proportional term , the integral term and the non-linear differential term , calculate the output signal of the controller, which is specifically implemented by the following formula: ; Among them, is the gain coefficient of the load .

[0012] The beneficial effects of adopting the above technical solutions are as follows: The present invention proposes a path tracking control method for a center hinge type scraper. By introducing a non-linear adjustment mechanism, it effectively solves the problems of strong non-linearity and large time delay inherent in the hydraulic steering system. This method can adaptively adjust the preview distance according to the real-time state of the center hinge type scraper, compensating for the non-linearity and hysteresis effects brought by the hydraulic system, thus significantly improving the path tracking accuracy and the robustness of the overall system. By adopting the adaptive preview distance, the present invention can calculate the feedback error in real time and process it by the non-linear feedback error controller to generate the actual control input. Compared with the traditional feedback error-based control method, the present invention performs more stably and has higher control accuracy under dynamic working conditions, ensuring the path tracking accuracy of the scraper under complex working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic flow chart of a path tracking control method for a center hinge type scraper in an embodiment of the present invention; Figure 2 is a schematic diagram of a center hinge type scraper in the forward movement in an embodiment of the present invention; Figure 3 is a schematic diagram of dynamically adjusting the preview distance of a center hinge type scraper in the forward movement in an embodiment of the present invention; Figure 4It is a schematic diagram of the expected state of the central hinge type scraper in the embodiment of the present invention; Figure 5 It is a schematic diagram of the telescopic movement of the hydraulic cylinder during the steering process of the central hinge type scraper in the embodiment of the present invention. Specific implementation manner

[0014] The following combines the drawings and embodiments to further describe in detail the specific implementation manner of the present invention. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0015] The purpose of the present invention is to provide a path tracking control method for a hydraulic center articulated scraper applicable to a complex underground mine environment. This method aims to overcome the insufficient applicability of existing path tracking control technologies in the face of dynamic characteristics such as the nonlinearity of the hydraulic system and vehicle state changes. Especially in the case where effective vehicle modeling cannot be carried out, high-precision path tracking control can still be achieved.

[0016] Specifically, the present invention provides a path tracking control method for a central hinge type scraper, combined with Figure 1 , which may include the following steps: Step 1: Through the vehicle-mounted sensors configured on the central hinge type scraper, including but not limited to 3D lidar and inertial measurement unit, collect the state information of the central hinge type scraper. The state information includes speed, front wheel center pose, and rear wheel center pose. The vehicle-mounted sensors transmit the state information to the main controller. Specifically, the vehicle-mounted sensors regularly transmit the state information to the main controller through the network interface; Step 2: In the main controller, determine the current state of the central hinge type scraper, that is, Figure 1 in the sensor information acquisition and processing part, the current state is expressed as: ; Among them, x is the abscissa of the reference state position G , y is the ordinate of the reference state position G , is the orientation angle, is the hinge angle; Specifically, in the main controller, according to the traveling state of the central hinge type scraper, select one of the front wheel center pose and the rear wheel center pose as the target center pose. The target center pose determines the reference state position and the orientation angle , Specifically, when the central hinge type scraper is moving forward, the target center pose is the front wheel center pose, and the reference state position G is the center of the front wheel , the orientation angle is the yaw angle of the front vehicle body in the world coordinate system. When the center hinge type scraper is running backward, the target center pose is the rear wheel center pose, and the reference state position G is the rear wheel center , and the orientation angle is the yaw angle of the rear vehicle body in the world coordinate system.

[0017] Determine the hinge angle according to the front wheel center pose and the rear wheel center pose , the hinge angle is the relative rotation angle between the front and rear vehicle bodies of the center hinge type scraper, the reference state position, the orientation angle and the hinge angle constitute the current state.

[0018] Figure 2 This is a schematic diagram of the center hinge type scraper in the forward movement case in the embodiment of the present invention. Among them, is the Cartesian coordinate system, P and Q respectively represent the rear wheel center and the front wheel center of the center hinge type scraper, is the hinge point between the front and rear vehicle bodies of the center hinge type scraper, is the instantaneous rotation center of the center hinge type scraper, is the hinge angle of the center hinge type scraper, and respectively represent the orientation angles of the front and rear vehicle bodies in the world coordinate system, and respectively represent the lengths of the front and rear vehicle bodies, and respectively represent the turning radii of the front and rear vehicle bodies. Combining Figure 2 , it can be clearly seen the representation of the parameters of the current state when the center hinge type scraper is in forward movement.

[0019] Step 3: Obtain the reference path RP , the reference path RP is composed of multiple discrete points. The points on the reference path are represented as: ; Among them, represents the point on the reference path, u is the reference path parameter, is the abscissa of is the ordinate of U is the domain of the path parameter; Step 4: On the reference path RP , determine the reference path point G corresponding to the reference state position , among which, is the abscissa of the reference path point ; is the ordinate of the reference path point ; is the path parameter of the reference path point ; Specifically, taking the reference path point as an unknown parameter, calculate the tangent vector of the reference path point ; , the component representation of which is: ; ; wherein, represents the first derivative of ; represents the first derivative of G ; Based on the reference state position and the tangent vector wherein, is the tangent vector at the reference path point ; Solve the tangent equation to obtain the solution set ; In the case of the solution set G select the point closest to the reference state position from the solution set as the reference path point ; the path parameter of the reference path point satisfies the following relationship: ; In the case of the solution set G select the point closest to the reference state position on the reference path as the reference path point ; ; Step 5: Calculate the Euclidean distance between the reference state position G and the reference path point ; G Take the Euclidean distance between the reference state position and the reference path point , which is specifically implemented through the following formula: ; Furthermore, the present invention proposes a method for dynamically adjusting the preview distance based on the real-time state, which takes into account the driving speed of the vehicle in the embodiments of the present invention v , the lateral error deviation between the reference state position and the reference path , the articulation angle .

[0020] Furthermore, to avoid instability in the control system, a smoothing mechanism is introduced in the adjustment process of the preview distance. By constraining the change amplitude of the preview distance, the adjustment process is ensured to be stable, avoiding the impact on control accuracy and system stability caused by excessive oscillation or response delay.

[0021] Step 6: Dynamically adjust the preview distance based on the speed v and the lateral error , that is, Figure 1 in the adaptive preview distance adjustment, and then determine the preview point L , the preview point L is the point on the reference path that is at a preview distance from the reference state position G , and the direction from the reference state position G to the preview point L is the preview direction; Among them, if there is no exactly matching point on the reference trajectory , the linear interpolation method is used to calculate between adjacent points to obtain a point that meets the preview distance requirement, which is determined as the position of the preview point .

[0022] Among them, based on the speed v and the lateral error , the dynamic adjustment of the preview distance is specifically implemented through the following formula: ; Among them, represents the preview distance, is used to adjust the sensitivity of the preview distance change, represents 's influence degree on the preview distance, represents the articulation angle 's influence degree on the preview distance.

[0023] Figure 3 is a schematic diagram of the dynamic adjustment of the preview distance when the center hinge type scraper is moving forward. Among them, Q represents the reference state position, is the reference path point, (a) represents a high lateral error 、 Small articulation angle and low speed schematic diagram, in this case, it will lead to a small preview distance, (b) represents high lateral error 、 Small articulation angle and high speed schematic diagram, in this case, it will lead to a small preview distance, (c) represents low lateral error 、 Small articulation angle and low speed schematic diagram, in this case, it will lead to a small preview distance, (d) represents low lateral error 、 Small articulation angle and high speed schematic diagram, in this case, it will lead to a large preview distance, (e) represents low lateral error 、 Large articulation angle and low speed schematic diagram, in this case, it will lead to a small preview distance; combined with Figure 3 , when the center hinge type scraper has a side slip or a large initial error, plays a dominant role, and different has little influence on ; when the center hinge type scraper enters the steady state ( is small), plays a dominant role, allowing the system to increase at high , low , small conditions, increasing the stability of path tracking; when the center hinge type scraper is on a curve ( is large), will decrease sharply, which helps the center hinge type scraper to recover its path under complex working conditions, while maintaining precise control when the curvature changes.

[0024] Step 7: Obtain the desired state of the center hinge type scraper , the desired state is expressed as: ; where, represents the desired articulation angle, and the desired articulation angle is the articulation angle corresponding to when the instantaneous desired path of the center hinge type scraper can pass through the preview point; Step 8: Calculate the angle between the current movement direction and the preview direction of the center hinge type scraper , and then calculate the expected state hinge angle component ; Figure 4 is a schematic diagram of the expected state of the center hinge type scraper in the embodiment of the present invention, where represents the joint point between the front and rear parts of the center hinge type scraper, with as the center, and the arc passing through point and point represents the instantaneous expected path of the center hinge type scraper. The dotted line and solid line passing through the preview point represent the reference path of the center hinge type scraper in the embodiment of the present invention. represents the expected position of the center of the rear wheel of the center hinge type scraper. represents the instantaneous rotation center of the center hinge type scraper in the expected state. represents the instantaneous turning radius of the center hinge type scraper. represents the expected hinge angle of the center hinge type scraper. represents the real-time preview point of the center hinge type scraper. represents the orientation of the rear vehicle body at the expected hinge angle.

[0025] Specifically, calculate the included angle between the current movement direction and the preview direction of the vehicle, which is specifically realized by the following formula: ; where is the component of the coordinate G of the reference state position y , is the component of the coordinate G of the reference state position x , is the component of the orientation angle G of the reference state position ; Since the value of the instantaneous turning radius is the size of the turning radius of the front vehicle, that is , a geometric equation is constructed according to the geometric relationship, and the geometric equation is expressed as: ; where is the length of the front vehicle body of the center hinge type scraper, is the length of the rear vehicle body of the center hinge type scraper, is the component of the expected state hinge angle ; The component of the expected state hinge angle is calculated from the geometric equation .

[0026] Furthermore, the present invention also calculates the articulated angle error , which is specifically achieved through the following formula: ; wherein, is the articulated angle G component of the reference state position ; Figure 5 is a schematic diagram of the telescopic movement of the hydraulic cylinder during the turning process of the center hinge type scraper. Among them, represents the joint point between the front and rear parts of the center hinge type scraper, and respectively represent the connection points between the hydraulic cylinder and the front and rear parts of the center hinge type scraper, and represent the corresponding connection points respectively when the joint angle is , is the articulated angle of the vehicle body in the initial state, and respectively represent the lengths from the articulated point of the center hinge type scraper to the front and rear connection points.

[0027] Step 9: Combine Figure 5 , calculate the relationship between the articulated angle and the telescopic amount of the hydraulic cylinder , and then calculate the feedback error ; Calculate the relationship between the articulated angle and the telescopic amount of the hydraulic cylinder , which is specifically achieved through the following formula: ; wherein, is the length from the articulated point to the first connection point, and the first connection point is the connection point between the hydraulic cylinder and the front vehicle body, is the length from the articulated point to the second connection point, and the second connection point is the connection point between the hydraulic cylinder and the rear vehicle body, is the initial length of the hydraulic cylinder; Based on the relationship between the articulated angle and the telescopic amount of the hydraulic cylinder , calculate the feedback error , which is specifically represented by the following formula: ; wherein, is the physical limit of the hinge angle.

[0028] Furthermore, the feedback error calculated in real time by the present invention, combined with a non-linear proportional, integral and differential controller, dynamically generates a steering valve opening command.

[0029] Step 10: According to the feedback error , calculate the proportional term of the controller , integral term and non-linear differential term , and then calculate the output signal of the controller, the output signal of the controller is used to adjust the opening degree of the steering valve in the hydraulic system.

[0030] Step 10.1: According to the feedback error , calculate the proportional term of the controller , which is specifically implemented by the following formula: ; wherein, is the proportional gain coefficient, is the saturation value of the proportional term, is the sign function; The exponential decay term enables to quickly saturate at large errors (such as large initial errors of center hinge type scrapers and experiencing external disturbances), which helps the center hinge type scraper to quickly return to the steady state.

[0031] Step 10.2: According to the feedback error , calculate the integral term of the controller , which is specifically implemented by the following formula: ; wherein, is the integral gain coefficient, is the saturation value of the integral term of; Compared with , the saturation characteristic of the hyperbolic tangent function is more gentle. While ensuring the control force during normal driving, it can suppress from over-control when the error accumulates too much (such as when the center hinge type scraper is driving on a path with a large curvature), avoid the oscillation caused by integral saturation, and reduce overshoot.

[0032] Step 10.3: According to the differential of the feedback error , calculate the non-linear differential term of the controller , which is specifically implemented by the following formula: ; wherein, is the differential gain coefficient, is the magnification factor, is the feedback error of the differential; has low sensitivity to noise. At the same time, due to The saturation value is not set, so as to rapidly increase the control strength when the error change rate is large.

[0033] Step 10.4: Based on the proportional term , the integral term and the non-linear differential term , calculate the output signal of the controller, which is specifically implemented through the following formula: ; where is the gain coefficient of the load .

[0034] The technical key points of the present invention are as follows: 1. High-precision path tracking: By accurately calculating the lateral error and adaptively adjusting the preview distance, it is ensured that the center hinge type scraper can accurately travel along the predetermined path.

[0035] 2. Strong real-time performance: The control method has a low computational complexity, is suitable for rapid implementation in a real-time control system, and can adapt to rapidly changing working conditions.

[0036] 3. High robustness: The non-linear control strategy effectively suppresses system oscillations. At the same time, the load gain coefficient and the adaptive adjustment mechanism are introduced to enhance the stability of the system under different load conditions and variable path environments.

[0037] The above description is only a preferred embodiment of the present disclosure and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present disclosure is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above inventive concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the embodiments of the present disclosure.

Claims

1. A path tracking control method for a center-hinged scraper, characterized in that: include: Step 1: collecting status information of the center-articulated scraper through a vehicle-mounted sensor configured for the center-articulated scraper, wherein the status information includes speed, front wheel center position and rear wheel center position, and the vehicle-mounted sensor transmits the status information to a main controller; Step 2: In the main controller, determine the current state of the center-articulated scraper, which is expressed as: ； in, x The reference state position G The horizontal axis of y The reference state position G The vertical coordinate of is the orientation angle, is the articulation angle; Step 3: Get the reference path RP , the reference path RP It is composed of multiple discrete points, and the points on the reference path are expressed as: ； in, represents a point in the reference path, u is the reference path parameter, for The horizontal axis of for The vertical coordinate of U is the domain of the path parameter; Step 4: In the reference path RP On, determine the reference state position G Corresponding reference path points ,in, Reference path point The horizontal axis of Reference path point The vertical coordinate, Reference path point Path parameters; Step 5: Calculate the reference state position G and reference waypoints The Euclidean distance between the reference state positions G and reference waypoints The Euclidean distance between , which is specifically achieved through the following formula: ； Step 6: Speed ​​Based v and lateral error , dynamically adjust the preview distance, and then determine the preview point L , the preview point L is the position of the reference state at all points in the reference path G The distance is the preview distance, the reference state position G Point to preview point L The direction is the preview direction; Step 7: Get the desired state of the center-hinged scraper , the desired state It is expressed as: ； in, represents an expected articulation angle, which is the articulation angle corresponding to the instantaneous expected path of the center-articulated scraper passing through the preview point; Step 8: Calculate the angle between the center-hinged scraper's current direction of motion and the preview direction , and then calculate the desired state articulation angle Quantity ; Step 9: Calculate the relationship between the articulation angle and the extension and contraction of the hydraulic cylinder , and then calculate the feedback error ; Step 10: Based on the feedback error , calculate the proportional term of the controller , integral term and nonlinear differential terms , and then calculate the output signal of the controller , the output signal of the controller Used to adjust the opening of the steering valve in the hydraulic system.

2. A path tracking control method for a center-hinged scraper according to claim 1, characterized in that: Step 2 specifically includes: In the main controller, according to the traveling state of the center-articulated scraper, one of the front wheel center posture and the rear wheel center posture is selected as the target center posture, and the target center posture determines the reference state position and the orientation angle. , according to the center pose of the front wheel and the center pose of the rear wheel, determine the articulation angle , the articulation angle is the relative rotation angle between the front and rear bodies of the center-hinged scraper, the reference state position, the orientation angle and articulation angle Make up the current state.

3. A path tracking control method for a center-hinged scraper according to claim 1, characterized in that: Step 4 specifically includes: Reference waypoints As unknown parameters, calculate the reference path points The tangent vector , The components are expressed as: ； ； in, express The first derivative of express The first derivative of ; Based on the reference state position G and the tangent vector , construct the tangent equation, which is expressed as: ； in, Reference path point The tangent vector at ; Solve the tangent equation and get the solution set , in the solution set In the case of G The closest point is used as the reference path point , in the solution set In the case of Upper selection and reference state position G The closest point is used as the reference path point .

4. The path tracking control method for a center-hinged scraper according to claim 1, characterized in that: Based on the speed in step 6 v and lateral error , the dynamic adjustment of the preview distance is realized by the following formula: ； in, Indicates the preview distance. Used to adjust the sensitivity of preview distance changes. express The degree of influence on the preview distance, Represents the hinge angle The degree of influence on the preview distance.

5. The path tracking control method for a center-hinged scraper according to claim 1, characterized in that: Step 8 specifically includes: Calculate the angle between the vehicle's current direction of movement and the preview direction , which is specifically achieved through the following formula: ； in, The reference state position G The y component of the coordinate, The reference state position G Coordinates x The weight, The reference state position G The orientation angle The amount of Since the value of the instantaneous turning radius is the turning radius of the preceding vehicle, a geometric equation is constructed according to the geometric relationship, and the geometric equation is expressed as follows: ； in, is the length of the front body of the center-hinged scraper, is the length of the rear body of the center-hinged scraper, is the desired state articulation angle The amount of The desired state articulation angle is calculated from the geometric equation Quantity .

6. A path tracking control method for a center-hinged scraper according to claim 1, characterized in that: Step 9 specifically includes: Calculate the relationship between the articulation angle and the extension and retraction of the hydraulic cylinder , which is specifically achieved through the following formula: ； in, is the length from the hinge point to the first connection point, where the first connection point is the connection point between the hydraulic cylinder and the front vehicle body, is the length from the hinge point to the second connection point, where the second connection point is the connection point between the hydraulic cylinder and the rear body, is the initial length of the hydraulic cylinder; Based on the relationship between the articulation angle and the extension and contraction amount of the hydraulic cylinder , calculate the feedback error , which is specifically expressed by the following formula: ； in, is the physical limit of the hinge angle.

7. The path tracking control method for a center-hinged scraper according to claim 1, characterized in that: Step 10 specifically includes: Step 10.1: Based on the feedback error , calculate the proportional term of the controller , which is specifically achieved through the following formula: ； in, is the proportional gain coefficient, is the saturation value of the proportional term, is a symbolic function; Step 10.2: Based on the feedback error , the integral term of the controller in the calculation , which is specifically achieved through the following formula: ； in, is the integral gain coefficient, The saturation value of the integral term; Step 10.3: Based on the feedback error The differential of , calculates the nonlinear differential term of the controller , which is specifically achieved through the following formula: ； in, is the differential gain coefficient, is the magnification, Feedback error The differential of Step 10.4: Based on the proportional term , integral term and nonlinear differential terms , calculate the output signal of the controller , which is specifically achieved through the following formula: ； in, is the load The gain factor of .

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