A full-axle steering control method and system for a multi-formation virtual rail vehicle
By dividing the multi-axle rail vehicle into multiple Ackermann steering geometry regions and using the collinearity of instantaneous velocity centers to weakly couple the regions, the problem of poor tracking accuracy and turning attitude coordination of multi-group virtual rail vehicles is solved, achieving higher vehicle operation stability and dynamic performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CRRC QINGDAO SIFANG CO LTD
- Filing Date
- 2023-06-13
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies cannot effectively coordinate the tracking accuracy and turning attitude of multi-group virtual track vehicles, resulting in poorer coordination with more tracking control points and unstable vehicle operation.
The multi-axle rail vehicle is divided into multiple Ackermann steering geometry regions. By using the instantaneous center-of-velocity collinearity method to weakly couple each region, multiple tracking control points are selected to achieve mutual coordination between multi-axle deviation feedback control and steering geometry.
It improves vehicle tracking accuracy and operational stability, reduces wear and tear when the vehicle is turning, and ensures vehicle stability and dynamic performance when navigating curves.
Smart Images
Figure CN116674604B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of railway vehicle steering control technology, and in particular to a method and system for all-axle steering control of multi-group virtual railway vehicles. Background Technology
[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.
[0003] Multi-car virtual rail vehicles are a new type of urban public transport vehicle. Their key feature is that they do not require physical railway tracks; they can operate simply by pre-setting virtual routes. This ensures high capacity while reducing investment in infrastructure construction. Virtual rail vehicles use image recognition, lidar positioning, and magnetic nail sensing to collect route information and then control the vehicles to travel along the predetermined routes. Due to the longer length of their multi-car configuration, all-axle steering is required to reduce the turning radius. All-axle steering control needs to consider vehicle tracking accuracy and turning attitude.
[0004] However, there is a contradiction between vehicle tracking accuracy and the coordination of vehicle turning posture. The more tracking control points a vehicle has, the more accurate the tracking control becomes, but the worse the coordination between different areas. Existing control methods cannot achieve perfect coordination between tracking accuracy and vehicle curvature posture, often resulting in a trade-off between the two. Summary of the Invention
[0005] To address the aforementioned issues, this invention proposes an all-axle steering control method and system for multi-group virtual rail vehicles. The all-axle is divided into multiple Ackermann steering geometry regions, enabling multi-axle deviation feedback control. Selecting multiple tracking control points can improve the vehicle's tracking accuracy, and the mutual coordination under each steering geometry allows each wheel to coordinate its operation through curves.
[0006] According to a first aspect of the present invention, a method for all-axle steering control of a multi-group virtual rail vehicle is provided, comprising:
[0007] The multi-axle rail vehicle is divided into multiple steering geometry regions, and the defined steering geometry regions are weakly coupled together by the method of collinearity of instantaneous velocity centers; the rotation angle relationship of each axle within each steering geometry region is determined according to the geometric relationship.
[0008] At least one tracking control point is selected in each steering region. The rotation angle of a certain axis in each steering geometry region is determined by the deviation of the tracking control point. The rotation angles of other axes in the steering geometry region are obtained according to the rotation angle relationship of each axis in the steering geometry region.
[0009] The all-axle steering of multi-group virtual rail vehicles is controlled based on the obtained rotation angles of each axle.
[0010] The multi-axle rail vehicle is divided into multiple steering geometry regions, specifically:
[0011] The first and second axles at the front of the lead car are divided into a single steering geometry region, referred to as the first region;
[0012] The third axle of the lead car and the fourth axle of the middle car, which is close to the third axle, are divided into a steering geometry region, called the second region;
[0013] The fifth axle of the middle car, which is close to the last car, and the sixth axle of the last car, which is close to the fifth axle, are divided into a steering geometry region, called the third region.
[0014] The seventh and eighth axles at the rear of the tail vehicle are divided into a steering geometry region, called the fourth region.
[0015] The defined steering geometry regions are weakly coupled together using the method of collinearity of instantaneous velocity centers, specifically as follows:
[0016] In both the first and second regions, the vertical line of the hinge side of the lead car is selected as the turning center line.
[0017] In both the third and fourth zones, the vertical line of the hinge side of the rear vehicle is selected as the turning center line.
[0018] According to a second aspect of the present invention, an all-axle steering control system for a multi-group virtual rail vehicle is provided, comprising:
[0019] The region division and coupling module is used to divide the multi-axle rail vehicle into multiple steering geometry regions, and weakly couple the set steering geometry regions together by the method of collinearity of instantaneous velocity centers; and determine the rotation angle relationship of each axle within each steering geometry region according to the geometric relationship.
[0020] The all-axle steering control module is used to select at least one tracking control point in each steering region, determine the rotation angle of a certain axle in each steering geometry region by the deviation of the tracking control point, obtain the rotation angle of other axles in the steering geometry region according to the rotation angle relationship of each axle in the steering geometry region, and control the all-axle steering of multi-group virtual rail vehicles based on the obtained rotation angles of each axle.
[0021] According to a third aspect of the present invention, a controller for multi-group virtual rail vehicles is provided, which uses the above-described method for controlling the all-axle steering of multi-group virtual rail vehicles to control the all-axle steering of multi-group virtual rail vehicles.
[0022] According to a fourth aspect of the present invention, a computer-readable storage medium is provided, wherein a plurality of instructions are stored, the instructions being adapted to be loaded by a processor of a terminal device and executed by the above-described method for all-axle steering control of multi-group virtual rail vehicles.
[0023] Compared with the prior art, the beneficial effects of the present invention are:
[0024] (1) This invention divides the entire axle of a multi-group virtual track vehicle into multiple Ackermann steering geometry regions, realizing multi-axis deviation feedback control. Selecting multiple tracking control points can improve the vehicle's tracking accuracy. At the same time, the multiple Ackermann steering geometries are weakly coupled together by the method of collinearity of instantaneous velocity centers, realizing mutual coordination under each steering geometry, enabling each wheel to run in coordination through the curve, and improving the vehicle's running stability.
[0025] (2) The present invention can control the speed of the vehicle hinge to be in the same direction by using the method of weak coupling with the instantaneous center of velocity collinearity, thereby reducing the wear of the vehicle hinge and improving the vehicle stability and curve passing effect while improving the accuracy of vehicle tracking control.
[0026] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0027] Figure 1 This is the basic principle of tracking control in the embodiments of the present invention;
[0028] Figure 2 This is a schematic diagram of the steering geometry region division of an eight-axle vehicle in an embodiment of the present invention;
[0029] Figure 3 This is a geometrical diagram illustrating the corner relationship of the second region in an embodiment of the present invention. Detailed Implementation
[0030] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.
[0031] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Furthermore, it should be understood that the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or apparatus.
[0032] Example 1
[0033] In one or more embodiments, a method for all-axle steering control of a multi-group virtual rail vehicle is disclosed, specifically including:
[0034] The multi-axle rail vehicle is divided into multiple steering geometry regions, and the defined steering geometry regions are weakly coupled together by the method of collinearity of instantaneous velocity centers; the rotation angle relationship of each axle within each steering geometry region is determined according to the geometric relationship.
[0035] In this embodiment, the first and second axles at the front end of the lead car are divided into a steering geometry region, called the first region; the third axle of the lead car and the fourth axle of the middle car near the third axle are divided into a steering geometry region, called the second region; the fifth axle of the middle car near the tail car and the sixth axle of the tail car near the fifth axle are divided into a steering geometry region, called the third region; and the seventh and eighth axles at the rear end of the tail car are divided into a steering geometry region, called the fourth region.
[0036] In both the first and second regions, the vertical line from the hinge side of the lead car is selected as the steering center line; in both the third and fourth regions, the vertical line from the hinge side of the tail car is selected as the steering center line.
[0037] At least one tracking control point is selected in each turning region. The rotation angle of a certain axis in each turning geometry region is determined by the deviation of the tracking control point. The rotation angles of other axes in the turning geometry region are obtained according to the rotation angle relationship of each axis in the turning geometry region. The all-axle steering of the multi-group virtual rail vehicle is controlled based on the obtained rotation angles of each axis.
[0038] Specifically, multiple points are selected on a multi-unit rubber-tired intelligent vehicle. The goal of the tracking control is to make these points coincide with the vehicle's preset trajectory line when the vehicle is moving. We call these points tracking control points.
[0039] The basic principles of tracking control are as follows: Figure 1 As shown, the system monitors whether there is a deviation in the tracking point using sensors. If there is a deviation, the tracking axis is controlled to turn in the opposite direction to reduce the deviation of the monitoring point. Then, the system continues to monitor and correct the deviation in a closed-loop control.
[0040] The control method in this embodiment divides each axle into multiple steering geometries. According to the Ackermann steering principle, each Ackermann steering geometry has a unique steering center (instantaneous velocity center) line. That is, regardless of the wheel steering angle, the point where the axles of all wheels intersect must lie on this straight line. Therefore, there is an inherent correspondence between the steering angles of each wheel under the same steering geometry. Furthermore, a single steering geometry region can only guarantee tracking control for a point near that region. The more steering geometry regions there are, the more tracking control points the vehicle has, and the more precise the tracking control becomes. Each steering geometry region is independent and can satisfy the coordination of the axles within the region, but the coordination between regions is poor. The fewer steering geometry regions there are, the better the overall vehicle posture. Therefore, control precision and overall vehicle coordination are contradictory; both tracking and posture must be considered, and the steering geometry regions must be rationally divided.
[0041] by Figure 2 Taking an eight-axle vehicle as an example, the eight axles are divided into multiple steering geometry regions. The first and second axles are located at the front of the lead vehicle and are relatively close. Therefore, grouping the first and second axles together facilitates control of the tracking point at the front of the vehicle and ensures coordination between the first and second axles. The third axle, however, is far from the front. Forcing it into the coupling of the first and second axles for steering, with only one control point, is detrimental to tracking control of the lead vehicle. If the tracking point near the fourth axle is used to control the tracking of the rear of the lead vehicle, the lateral deviation of the lead vehicle's rear is large under the control system, while the lateral deviation of the middle vehicle's front is small. Since the two vehicles are connected by hinges, this would cause tire drag between the third and fourth axles, increasing the load on the hinges and affecting vehicle stability. The middle vehicle is articulated with vehicles at both ends, so it cannot be separated from the vehicles at the front and rear. Furthermore, each geometry region can only control one tracking point. Therefore, grouping the fourth and fifth axles into the same steering geometry is also unreasonable. The third and fourth axes are relatively close together and have a hinge between them, so it is reasonable to group them together and control both tracking accuracy and attitude simultaneously. Similarly, assigning the fifth and sixth axes to the same steering geometry, and the seventh and eighth axes to the same steering geometry, is a better solution.
[0042] Each steering geometry region can be controlled by using the tracking deviation at a monitoring point as a reference, thus controlling the steering angle of the two axles and four wheels within that region. This conforms to the local curved planar motion law and provides strong control over tracking deviation. However, each steering geometry is independent of the others. While this control method takes into account the coordination of the wheels on each axle and the accuracy of tracking control within the same region, it cannot take into account the overall vehicle attitude.
[0043] This embodiment further employs a weak coupling process for the first and second regions (i.e., the front four axles), and the third and fourth regions (i.e., the rear four axles): the first and second regions both use the vertical line of the hinge side of the lead vehicle as the steering centerline, while the third and fourth regions both use the vertical line of the hinge side of the tail vehicle as the steering centerline. This weak coupling ensures that the velocity direction of the two hinged joints is always along the centerline of the lead and tail vehicles, thereby reducing unnecessary lateral movement of the hinges, ensuring the stability of the middle vehicle, and reducing hinge wear.
[0044] Under this theoretical framework, the relationships between the rotation angles of each axis can be derived through steering geometry:
[0045] Within the first region, the wheel angle relationship between the first and second axles is as follows (the wheel angle relationship between the inner and outer wheels on the same axle can be obtained through Ackermann steering geometry, and will not be derived here):
[0046] L1cotδ1=L2cotδ2 (1)
[0047]
[0048] Where δ1 and δ2 are the rotation angles of the first axis and the second axis, respectively, and L1 and L2 are the rotation angles of the first axis and the second axis, respectively.
[0049] The distance from the second axle to its nearest hinge.
[0050] The geometric relationship of the corners in the second region is as follows: Figure 3 As shown, an auxiliary triangle is constructed by extending the centerline of the vehicle and comparing it with the wheel axles of the four axles at a point. Figure 2 and Figure 3 In the diagram, O1 and O2 are the steering centers (instantaneous velocity centers) of each steering geometry, respectively, and δ j L represents the steering angle of each axle wheel. j The distance from each axle to the nearest hinge is represented by j = 1, 2, ..., 8; θ1 and θ2 represent the relative rotation angles (angles between the front and rear axles) of the front and rear hinges, respectively.
[0051] The solid curve in the middle represents the vehicle's running path. The three squares represent the vehicle body, and the eight black rounded squares represent the wheels on each axle (the inner and outer turning angles of wheels on the same axle are different, so one wheel is used here for simplification). The two dashed lines are the side vertical lines at the hinges of the front and rear vehicles (which are also the steering center lines of the Ackermann steering geometry).
[0052] According to the steering geometry:
[0053]
[0054]
[0055]
[0056] By the Law of Sines:
[0057]
[0058] From equations (2) to (6), the relationship between the wheel angles of the three- and four-axle wheels can be obtained:
[0059]
[0060] Where δ3 and δ4 are the rotation angles of the third and fourth axles, respectively; L3 and L4 are the distances from the third and fourth axles to their nearest hinges, respectively; α is the interior angle of the auxiliary triangle; L is the side length of the auxiliary triangle; θ1 represents the relative rotation angle of the front hinge (the angle between the front axle axes); and e2 represents the distance from the instantaneous center of the wheel speed O2 of the two axles to the hinge between the two axles.
[0061] For the third region, the specific angular relationship between the fifth and sixth axes is as follows: (Please provide the formula).
[0062]
[0063] Where δ5 and δ6 are the rotation angles of the fifth and sixth axles, respectively, and L5 and L6 are the distances from the fifth and sixth axles to their nearest hinges, respectively; θ2 represents the relative rotation angle of the tail hinge.
[0064] For the fourth region, the specific angular relationship between the seventh and eighth axes is as follows: (Please provide the formula).
[0065]
[0066] Where δ7 and δ8 are the rotation angles of the seventh and eighth axes, respectively, and L7 and L8 are the distances from the seventh and eighth axes to their nearest hinges, respectively.
[0067] Under the control method of this embodiment, the four regions retain their independence. Four tracking control points can be selected as needed to control their lateral deviation. The rotation angle of a certain axis in each region is obtained by PID control and other methods based on the magnitude of the deviation. The remaining angles are determined by the above formula. That is, the controller can complete the full-axis control of the vehicle by outputting four steering angles. Moreover, while improving the accuracy, the vehicle's posture can also be guaranteed.
[0068] This embodiment integrates deviation feedback control and multi-axis coordinated control technology, coupling the steering angles of multiple axes together. This reduces the deviation in vehicle tracking and keeps the wheels in a better curve running state, avoiding wheel dragging problems, reducing wheel wear, and thus improving the vehicle's dynamic performance.
[0069] Example 2
[0070] In one or more embodiments, an all-axle steering control system for a multi-group virtual rail vehicle is disclosed, comprising:
[0071] The region division and coupling module is used to divide the multi-axle rail vehicle into multiple steering geometry regions, and weakly couple the set steering geometry regions together by the method of collinearity of instantaneous velocity centers; and determine the rotation angle relationship of each axle within each steering geometry region according to the geometric relationship.
[0072] The all-axle steering control module is used to select at least one tracking control point in each steering region, determine the rotation angle of a certain axle in each steering geometry region by the deviation of the tracking control point, obtain the rotation angle of other axles in the steering geometry region according to the rotation angle relationship of each axle in the steering geometry region, and control the all-axle steering of multi-group virtual rail vehicles based on the obtained rotation angles of each axle.
[0073] It should be noted that the specific implementation methods of the above modules have been described in detail in Example 1, and will not be repeated here.
[0074] Example 3
[0075] In one or more embodiments, a multi-group virtual rail vehicle controller is disclosed, which uses the all-axle steering control method for multi-group virtual rail vehicles described in Embodiment 1 to control the all-axle steering of the multi-group virtual rail vehicles.
[0076] Example 4
[0077] In one or more embodiments, a computer-readable storage medium is disclosed, wherein a plurality of instructions are stored, the instructions being adapted to be loaded by a processor of a terminal device and executed by the above-described method for all-axle steering control of multi-group virtual rail vehicles.
[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.
Claims
1. A method for all-axle steering control of a multi-unit virtual rail vehicle, characterized in that, include: The multi-axle rail vehicle is divided into multiple steering geometry regions, which are Ackermann steering geometry regions. Specifically, the third axle of the lead car and the fourth axle of the intermediate car (close to the third axle) are divided into one steering geometry region, called the second region; the fifth axle of the intermediate car (close to the tail car) and the sixth axle of the tail car (close to the fifth axle) are divided into another steering geometry region, called the third region. The defined steering geometry regions are weakly coupled together using the method of collinearity of instantaneous velocity centers. The vertical line of the lead car's hinge side is selected as the steering center line for the second region, and the vertical line of the tail car's hinge side is selected as the steering center line for the third region. The rotation angle relationship of each axle within each steering geometry region is determined according to the geometric relationship. For the steering geometry region defined by the third axle of the lead car and the fourth axle of the middle car (closer to the third axle), the specific angular relationship between the third and fourth axles is as follows: in, , These are the rotation angles of the third and fourth axes, respectively. , These are the distances from the third and fourth axles to their nearest hinges, respectively. Indicates the relative rotation angle of the lead car's hinge; At least one tracking control point is selected in each steering region. The rotation angle of a certain axis in each steering geometry region is determined by the deviation of the tracking control point. The rotation angles of other axes in the steering geometry region are obtained according to the rotation angle relationship of each axis in the steering geometry region. The all-axle steering of multi-group virtual rail vehicles is controlled based on the obtained rotation angles of each axle.
2. The all-axle steering control method for a multi-group virtual rail vehicle as described in claim 1, characterized in that, Dividing multi-axle rail vehicles into multiple steering geometry regions also includes: The first and second axles at the front of the lead car are divided into a single steering geometry region, referred to as the first region; The seventh and eighth axles at the rear of the tail vehicle are divided into a steering geometry region, called the fourth region.
3. The all-axle steering control method for a multi-group virtual rail vehicle as described in claim 2, characterized in that, The defined steering geometry regions are weakly coupled together using the method of collinearity of instantaneous velocity centers, and also include: The first region selects the vertical line of the hinge side of the lead car as the turning center line; The fourth region selects the vertical line of the hinge side of the rear vehicle as the turning center line.
4. A method for all-axle steering control of a multi-unit virtual rail vehicle as described in claim 1 or 2, characterized in that, For the steering geometry region divided by the first and second axles at the front of the lead car, the specific angular relationship between the first and second axles is as follows: in, , These are the rotation angles of the first and second axes, respectively. , These are the distances from the first axle and the second axle to their nearest hinges, respectively.
5. A method for all-axle steering control of a multi-unit virtual rail vehicle as described in claim 1 or 2, characterized in that, For the steering geometry regions defined by the fifth axle of the middle car closest to the rear car and the sixth axle of the rear car closest to the fifth axle, the specific angular relationship between the fifth and sixth axles is as follows: in, , These are the rotation angles of the fifth and sixth axes, respectively. , These are the distances from the fifth and sixth axles to their nearest hinges, respectively. This indicates the relative rotation angle of the tail car's hinge.
6. A method for all-axle steering control of a multi-unit virtual rail vehicle as described in claim 1 or 2, characterized in that, For the steering geometry region defined by the seventh and eighth axles at the rear of the tail vehicle, the specific angular relationship between the seventh and eighth axles is as follows: in, , These are the rotation angles of the seventh and eighth axes, respectively. , These are the distances from the seventh and eighth axles to their nearest hinges, respectively.
7. A multi-train virtual rail vehicle all-axle steering control system, employing the all-axle steering control method for multi-train virtual rail vehicles as described in any one of claims 1-6, characterized in that, include: The region division and coupling module is used to divide the multi-axle rail vehicle into multiple steering geometry regions, and weakly couple the set steering geometry regions together by the method of collinearity of instantaneous velocity centers; and determine the rotation angle relationship of each axle within each steering geometry region according to the geometric relationship. The all-axle steering control module is used to select at least one tracking control point in each steering region, determine the rotation angle of a certain axis in each steering geometry region by the deviation of the tracking control point, and obtain the rotation angle of other axes in the steering geometry region according to the rotation angle relationship of each axis in the steering geometry region. The all-axle steering of multi-group virtual rail vehicles is controlled based on the obtained rotation angles of each axle.
8. A multi-group virtual rail vehicle controller, characterized in that, The all-axle steering control method for multi-group virtual rail vehicles as described in any one of claims 1-6 is used to control the all-axle steering of multi-group virtual rail vehicles.
9. A computer-readable storage medium storing a plurality of instructions, characterized in that, The instructions are adapted to be loaded by the processor of the terminal device and executed by the all-axle steering control method for multi-group virtual rail vehicles according to any one of claims 1-6.