Steering mode safe switching control method of angle module vehicle
By receiving mode switching commands and querying the mode switching relationship table in the corner module vehicle, and combining bridge mode transition and wheel steering control torque calculation, the reliability and stability issues of the corner module vehicle during multiple mode switching processes are solved, and smooth steering mode switching is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TSINGHUA UNIVERSITY
- Filing Date
- 2025-12-25
- Publication Date
- 2026-04-21
AI Technical Summary
How to ensure reliability during the steering mode switching process of corner module vehicles, especially the safety and stability when switching between multiple modes, is a challenge that existing methods lack in terms of flexibility and versatility.
By receiving the mode switching command, the system queries the pre-stored mode switching relationship table to determine whether the current steering mode can be directly switched to the target steering mode. If not, the system uses the bridge mode as a transition to switch to the target steering mode. The system also determines the target constraint conditions based on the type of the target steering mode and calculates the steering control torque of each wheel to achieve a smooth switch.
It reduces the risk of vehicle instability during mode switching, ensures the reliability and smoothness of vehicle status changes, and achieves reliability and safety during different mode switching processes.
Smart Images
Figure CN121894035A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of vehicle control technology, and in particular to a method for safe switching control of steering modes for corner module vehicles. Background Technology
[0002] Driven by the electrification and intelligentization of automobiles, chassis configurations are evolving towards highly integrated corner modules. Corner modules integrate a large number of drive-by-wire actuators, possessing a high degree of control freedom. This breaks the mechanical constraints of traditional steering, enabling single-wheel steering angles to reach 90 degrees. Consequently, corner module vehicles can achieve steering modes such as diagonal driving, lateral driving, and stationary turning.
[0003] However, before enjoying the convenience brought by these flexible steering modes, ensuring the reliability of the switching process between different steering modes has become a key issue that urgently needs to be addressed. Summary of the Invention
[0004] Therefore, it is necessary to provide a steering mode safe switching control method for corner module vehicles that can ensure reliability during the switching process of different modes, in order to address the above-mentioned technical problems.
[0005] In a first aspect, this application provides a method for switching steering modes of a corner module vehicle, comprising: receiving a mode switching instruction, the mode switching instruction including switching information for instructing the corner module vehicle to switch to a target steering mode; querying a pre-stored mode switching relationship table to determine whether the current steering mode of the corner module vehicle can be switched to the target steering mode; the mode switching relationship table including switching relationships between multiple steering modes of the corner module vehicle; if yes, controlling the corner module vehicle to switch from the current steering mode to the target steering mode; if no, controlling the corner module vehicle to switch from the current steering mode to a bridge mode, and then controlling the corner module vehicle to switch from the bridge mode to the target steering mode.
[0006] In one embodiment, the corner module vehicle has multiple steering modes including standard mode, diagonal mode, ramp parking mode, lateral movement mode, U-turn mode, stationary turning mode, and U-turn mode along center point; the bridge mode includes standard mode and stationary turning mode.
[0007] In one embodiment, the switching relationships between multiple steering modes in the mode switching relationship table include at least one of the following:
[0008] The standard mode can be switched to any of the multiple steering modes other than the standard mode;
[0009] The stationary steering mode can be switched to any of the multiple steering modes except for the diagonal driving mode and the stationary steering mode.
[0010] The slant mode can be switched to the standard mode, but cannot be switched to any of the multiple steering modes other than the standard mode.
[0011] Both the U-shaped steering mode and the center-point U-shaped steering mode can be switched to the standard mode and the stationary steering mode, but neither can be switched to any other steering mode among the multiple steering modes other than the standard mode and the stationary steering mode;
[0012] The ramp parking mode can be switched to standard mode, lateral movement mode, and stationary turning mode, but cannot be switched to inclined mode, ramp parking mode, U-turn mode, or center point U-turn mode.
[0013] Lateral movement mode can be switched to standard mode, slope parking mode and stationary turning mode, but cannot be switched to diagonal mode, lateral movement mode, U-turn mode and center point U-turn mode.
[0014] In one embodiment, controlling the corner module vehicle to switch from the current steering mode to the target steering mode includes: determining target constraints based on the type of the target steering mode; determining the steering control torque of each wheel of the corner module vehicle based on the target constraints; and controlling each wheel based on the steering control torque of each wheel to control the corner module vehicle to switch from the current steering mode to the target steering mode.
[0015] In one embodiment, determining the target constraint condition based on the type of the target steering mode includes: if the target steering mode is a type without an instantaneous center of rotation, then using a first constraint condition as the target constraint condition; the first constraint condition includes the following:
[0016]
[0017]
[0018]
[0019] in, , , These are the steering angles of the outer front wheel, the inner front wheel, and the reference front wheel of the angle module vehicle, respectively. , , These are the steering angles of the outer rear wheel, the inner rear wheel, and the reference rear wheel of the angle module vehicle, respectively. and These are the front and rear axle track widths of the corner module vehicle, respectively. This is the virtual wheelbase between the front axle reference wheel and the rear axle reference wheel; This represents the actual wheelbase between the front axle reference wheel and the rear axle reference wheel. It is the ratio of the steering angle of the rear axle reference wheel to the steering angle of the front axle reference wheel.
[0020] In one embodiment, determining the target constraint condition based on the type of the target steering mode includes: if the target steering mode is one with an instantaneous center of rotation, and the front and rear axles of the corner module vehicle have the same instantaneous center of rotation, then a second constraint condition is used as the target constraint condition; the second constraint condition includes the following:
[0021]
[0022] in, The first in the corner module vehicle The steering angle of each wheel; The first in the corner module vehicle The position of the wheel center; This is the position of the instantaneous center of rotation.
[0023] In one embodiment, the movement trajectory of the instantaneous center of rotation during the mode switching process is a curve passing through the center of mass of the wheel, which is the center of mass of multiple wheels of the corner module vehicle.
[0024] In one embodiment, the target constraint is determined based on the type of the target steering mode, including: if the target steering mode is one with an instantaneous center of rotation, and the front and rear axles of the corner module vehicle do not have the same instantaneous center of rotation, then a third constraint is used as the target constraint; the third constraint includes the following:
[0025]
[0026] in, and The corner module vehicles are respectively the first The steering angle of the first front axle wheel and the first Steering angle of each rear axle wheel; and The corner module vehicles are respectively the first The wheel center position of the first front axle wheel and the first The position of the wheel center of each rear axle wheel; and These are the positions of the instantaneous center of rotation of the front axle and the rear axle, respectively.
[0027] In one embodiment, the trajectory of the instantaneous center of rotation of the front axle during mode switching is a straight line moving along the first centerline in the first direction; the trajectory of the instantaneous center of rotation of the rear axle during mode switching is a straight line moving along the second centerline in the second direction; wherein the first direction is opposite to the second direction; the first centerline is a straight line passing through the center points of the two front axle wheels in the corner module vehicle; the second centerline is a straight line passing through the center points of the two rear axle wheels in the corner module vehicle.
[0028] Secondly, this application also provides a steering mode switching device for a corner module vehicle, comprising:
[0029] The receiving module is used to receive mode switching instructions, which include switching information for the indicator module vehicle to switch to the target steering mode;
[0030] The control module is used to query a pre-stored mode switching relationship table to determine whether the current steering mode of the corner module vehicle can be switched to the target steering mode. The mode switching relationship table includes the switching relationship between multiple steering modes. If yes, the control module vehicle switches from the current steering mode to the target steering mode. If no, the control module vehicle switches from the current steering mode to the bridge mode, and then switches from the bridge mode to the target steering mode.
[0031] Thirdly, this application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method described in any one of the first aspects above.
[0032] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in any one of the first aspects above.
[0033] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the method described in any one of the first aspects above.
[0034] The aforementioned steering mode switching control method, device, computer equipment, storage medium, and program product for corner module vehicles, by receiving a mode switching instruction (which includes switching information instructing the corner module vehicle to switch to a target steering mode), querying a pre-stored mode switching relationship table, and determining whether the current steering mode of the corner module vehicle can switch to the target steering mode; the mode switching relationship table includes the switching relationships between multiple steering modes of the corner module vehicle; if yes, the corner module vehicle is controlled to switch from the current steering mode to the target steering mode; if no, the corner module vehicle is controlled to switch from the current steering mode to the bridge mode, and then controlled to switch from the bridge mode to the target steering mode. This approach, by pre-defining the mode switching relationship table and introducing the bridge mode as a transition, reduces the risk of vehicle instability during mode switching, making vehicle state changes more stable and controllable, and ensuring reliability during different mode switching processes. Attached Figure Description
[0035] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0036] Figure 1 This is a schematic diagram of multiple steering modes of a corner module vehicle in one embodiment;
[0037] Figure 2 This is a flowchart illustrating a steering mode switching method for a corner module vehicle in one embodiment.
[0038] Figure 3 This is a flowchart illustrating the steering mode switching method for a corner module vehicle in another embodiment;
[0039] Figure 4 This is a schematic diagram of the equivalent models of the front axle reference wheel and the rear axle reference wheel in one embodiment;
[0040] Figure 5 This is a schematic diagram of an equivalent model of the front axle reference wheel and the rear axle reference wheel in another embodiment;
[0041] Figure 6 This is a schematic diagram of a steering mode in which the front and rear axles of a vehicle have the same instantaneous center of rotation in one embodiment.
[0042] Figure 7 This is a schematic diagram illustrating how the instantaneous center of rotation changes along a straight line in one embodiment;
[0043] Figure 8This is a schematic diagram illustrating how the instantaneous center of rotation changes along a curve in one embodiment;
[0044] Figure 9 This is a schematic diagram of a steering mode in which the front and rear axles of a vehicle do not have the same instantaneous center of rotation in one embodiment.
[0045] Figure 10 This is a schematic diagram of the change in the steering angle of the wheel over time during mode switching in one embodiment.
[0046] Figure 11 This is a structural block diagram of the steering mode switching device for a corner module vehicle in one embodiment;
[0047] Figure 12 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation
[0048] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0049] It should be noted that the terms "first," "second," etc., used in this application can be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. The terms "comprising" and "having," and any variations thereof, used in this application, are intended to cover non-exclusive inclusion. The term "multiple" used in this application refers to two or more. The term "and / or" used in this application refers to one of the embodiments, or any combination of multiple embodiments.
[0050] With the rapid development of vehicle electrification and intelligence, traditional mechanical drive and steering methods can no longer meet the requirements of vehicles in terms of agility, safety, and adaptability to various scenarios. The chassis configuration of intelligent vehicles is evolving towards highly integrated corner modules, which are also regarded as a promising carrier for new chassis coordinated control. Corner modules integrate a large number of drive-by-wire actuators, possessing high degrees of control freedom, breaking the mechanical constraints of traditional steering, and enabling a single-wheel steering angle of up to 90 degrees. As a result, corner module vehicles can achieve steering modes such as diagonal driving, lateral driving, and turning on the spot.
[0051] However, before enjoying the convenience brought by these flexible steering modes, ensuring the reliability of the switching process between different steering modes has become a key issue that urgently needs to be addressed.
[0052] Existing methods for constraining wheel steering distribution have shortcomings in terms of flexibility and versatility. For example, methods based on instantaneous steering center lack flexibility and do not provide methods for instantaneous center transfer across infeasible regions. During mode switching, existing methods do not define steering angle changes within a sufficiently strict range to ensure vehicle safety and controllability. For instance, some studies focus only on one or two specific movement modes without comprehensively considering steering angle control during multiple mode switching. When the vehicle performs steering angle control during mode switching, existing methods only use PID (Proportional-Integral-Derivative) or sliding mode control, which cannot guarantee complete reliability of each state during the switching process, leading to a certain degree of reduction in vehicle reliability and safety.
[0053] Therefore, it is necessary to propose effective technical means to solve the above-mentioned technical problems. The following detailed explanation, in conjunction with the accompanying drawings, illustrates how this application solves the aforementioned technical problems.
[0054] In one exemplary embodiment, such as Figure 2 As shown, a method for switching steering modes in a corner module vehicle is provided. Taking the application of this method to a terminal (vehicle) as an example, the method includes:
[0055] Receive mode switching instructions, which include switching information for indicating the angle module vehicle to switch to the target steering mode;
[0056] Query the pre-stored mode switching relationship table to determine whether the current steering mode of the corner module vehicle can be switched to the target steering mode; the mode switching relationship table includes the switching relationships between multiple steering modes of the corner module vehicle.
[0057] If so, the control angle module switches the vehicle from the current steering mode to the target steering mode;
[0058] If not, after the vehicle in the control angle module switches from the current steering mode to the bridge mode, the vehicle in the control angle module switches from the bridge mode to the target steering mode.
[0059] The corner module vehicle offers multiple steering modes, including Standard Mode, Diagonal Mode, Slope Parking Mode, Lateral Movement Mode, U-Turning Mode, Stationary Steering Mode, and Center-Point U-Turning Mode. Bridge Mode includes Standard Mode and Stationary Steering Mode. Diagonal Mode, Slope Parking Mode, Lateral Movement Mode, U-Turning Mode, Stationary Steering Mode, and Center-Point U-Turning Mode provide high maneuverability and can be collectively referred to as special modes. Standard Mode refers to a configuration dependent on steering wheel input, designed for traditional vehicle operation, and possesses independent four-wheel steering capability. It is considered the default operating mode for the corner module vehicle when no special modes are activated. It should be noted that the main difference between U-Turning Mode and Center-Point U-Turning Mode is that U-Turning Mode does not have a fixed center point during the U-turn, while Center-Point U-Turning Mode strictly uses a single center point for the U-turn.
[0060] like Figure 1 As shown, a schematic diagram of multiple steering modes for a corner module vehicle is provided. Figure 1 Figure (a1) is a schematic diagram of the standard mode; Figure (a2) is a schematic diagram of the diagonal mode; Figure (a3) is a schematic diagram of the lateral movement mode; Figure (a4) is a schematic diagram of the U-shaped turning mode; Figures (a5)-(a8) and (a10)-(a12) are schematic diagrams of the U-shaped turning mode along the center point; Figure (a9) is a schematic diagram of the stationary turning mode; Figures (a13) and (a14) are schematic diagrams of the ramp parking mode. It should be noted that Figures (a5)-(a8) can also be called the compass turn mode; Figure (a13) is the uphill type ramp parking mode, and Figure (a14) is the downhill type ramp parking mode.
[0061] Understandable. Figure 1 In This refers to the speed of the vehicle's left front wheel being 0. This means the speed of the vehicle's right front wheel is 0. This refers to the speed of the vehicle's left rear wheel being 0. This refers to the speed of the vehicle's right rear wheel being 0; IC represents the instantaneous center of rotation. , , These represent the steering angles of the vehicle's left front wheel, right front wheel, and left rear wheel, respectively; Front indicates the front of the vehicle, and Rear indicates the rear of the vehicle.
[0062] The switching relationships between multiple steering modes in the mode switching relationship table include at least one of the following:
[0063] The standard mode can be switched to any of the multiple steering modes other than the standard mode;
[0064] The stationary steering mode can be switched to any of the multiple steering modes except for the diagonal driving mode and the stationary steering mode.
[0065] The slant mode can be switched to the standard mode, but cannot be switched to any of the multiple steering modes other than the standard mode.
[0066] Both the U-shaped steering mode and the center-point U-shaped steering mode can be switched to the standard mode and the stationary steering mode, but neither can be switched to any other steering mode among the multiple steering modes other than the standard mode and the stationary steering mode;
[0067] The ramp parking mode can be switched to standard mode, lateral movement mode, and stationary turning mode, but cannot be switched to inclined mode, ramp parking mode, U-turn mode, or center point U-turn mode.
[0068] Lateral movement mode can be switched to standard mode, slope parking mode and stationary turning mode, but cannot be switched to diagonal mode, lateral movement mode, U-turn mode and center point U-turn mode.
[0069] The contents of the above mode switching relationship table are represented in tabular form, see Table 1, where "-" indicates that they cannot be switched between each other; "o" indicates that they can be switched between each other.
[0070] Table 1
[0071]
[0072] In one possible implementation, the driver can input mode switching commands via voice or manual touch. For example, if the driver says "switch to lateral movement mode," the vehicle's voice processing system can recognize the voice command and obtain the mode switching command.
[0073] Upon receiving the mode switching command, the vehicle queries the pre-stored mode switching relationship table to determine whether the current steering mode of the corner module vehicle can be directly switched to the target steering mode. If it can be directly switched, the corner module vehicle is controlled to switch from the current steering mode to the target steering mode. If it cannot be directly switched, the corner module vehicle is controlled to switch from the current steering mode to the bridge mode, and then the corner module vehicle is controlled to switch from the bridge mode to the target steering mode, thus achieving indirect switching.
[0074] The aforementioned steering mode switching control method for corner module vehicles receives a mode switching command, which includes switching information instructing the corner module vehicle to switch to a target steering mode. It then queries a pre-stored mode switching relationship table to determine if the current steering mode of the corner module vehicle can be switched to the target steering mode. The mode switching relationship table includes the switching relationships between multiple steering modes of the corner module vehicle. If yes, the corner module vehicle is controlled to switch from the current steering mode to the target steering mode. If not, the corner module vehicle is controlled to switch from the current steering mode to the bridge mode, and then controlled to switch from the bridge mode to the target steering mode. By pre-defining the mode switching relationship table and introducing the bridge mode as a transition, the risk of vehicle instability during mode switching is reduced, making vehicle state changes more stable and controllable, and ensuring reliability during different mode switching processes.
[0075] It is understood that the distributed electric drive corner module chassis of the corner module vehicle in this application is an overdrive system with a high degree of controllable freedom. The steering relationship between the wheels is no longer constrained by mechanical structures. To transform the overdrive system into a full-drive system and achieve the aforementioned steering mode, virtual constraints are required. The virtual constraints for different scenarios are described in detail below.
[0076] In one exemplary embodiment, such as Figure 3 The diagram illustrates another method for switching steering modes for a corner module vehicle. Controlling the corner module vehicle to switch from the current steering mode to the target steering mode includes:
[0077] Step 301: Determine the target constraints based on the type of target turning mode.
[0078] The aforementioned steering modes can be categorized into three types: those without a rotational instantaneous center of rotation, those with a rotational instantaneous center of rotation where the front and rear axles of the corner module vehicle share the same rotational instantaneous center of rotation, and those with a rotational instantaneous center of rotation where the front and rear axles of the corner module vehicle do not share the same rotational instantaneous center of rotation. Steering modes without a rotational instantaneous center of rotation include standard mode, diagonal mode, and lateral movement mode; steering modes with a rotational instantaneous center of rotation where the front and rear axles of the corner module vehicle share the same rotational instantaneous center of rotation include U-turn mode, stationary turn mode, and U-turn mode along the center point; and steering modes with a rotational instantaneous center of rotation where the front and rear axles of the corner module vehicle do not share the same rotational instantaneous center of rotation include slope parking mode.
[0079] In one possible implementation, such as Figure 4 and Figure 5 As shown, a schematic diagram of an equivalent model of a front axle reference wheel and a rear axle reference wheel is provided. Figure 5 The figure shows the changes in virtual wheelbase when the instantaneous centers of rotation are located at different positions.
[0080] If the target steering mode is one that does not have an instantaneous center of rotation, then the first constraint condition will be used as the target constraint condition; the first constraint condition includes the following:
[0081]
[0082]
[0083]
[0084] in, , , These are the steering angles of the outer front wheel, the inner front wheel, and the reference front wheel of the angle module vehicle, respectively. , , These are the steering angles of the outer rear wheel, the inner rear wheel, and the reference rear wheel of the angle module vehicle, respectively. and These are the front and rear axle track widths of the corner module vehicle, respectively. This is the virtual wheelbase between the front axle reference wheel and the rear axle reference wheel; This represents the actual wheelbase between the front axle reference wheel and the rear axle reference wheel. This is the ratio of the steering angle of the rear axle reference wheel to the steering angle of the front axle reference wheel. It can be understood that the front and rear track widths of a modular vehicle are equal, that is... Figure 4 T in the middle.
[0085] The ratio of the steering angle of the rear axle reference wheel to the steering angle of the front axle reference wheel. for:
[0086]
[0087] in, , These are the distances from the vehicle's center of gravity to the front axle and the distances from the vehicle's center of gravity to the rear axle, respectively. , These are the equivalent steering stiffness of the front axle and the equivalent steering stiffness of the rear axle, respectively. The longitudinal speed of the vehicle; The mass of the vehicle. The ratio of the steering angle of the rear axle reference wheel to the steering angle of the front axle reference wheel. It has a significant impact on the yaw stability of the vehicle.
[0088] Based on this, the problem of front-to-rear axle ratio is transformed into a method of constraining the front-to-rear wheel steering angle ratio using the concept of virtual wheelbase or virtual rear axle. Once the ratio of the steering angle of the rear axle reference wheel to the steering angle of the front axle reference wheel is determined... Once determined, the virtual wheelbase between the front axle reference wheel and the rear axle reference wheel is... The value can then be determined. After determining the geometric distribution between the two axles, according to Ackerman geometry, the inner and outer wheels can be naturally distinguished during steering based on the vehicle's state. When the desired Ackerman steering ratio is 100%, the relationship between the steering angle of the reference wheel on each axle and the steering angles of the inner and outer wheels as defined by the constraints is as shown in the first constraint condition.
[0089] In another possible implementation, such as Figure 6 The diagram illustrates a steering mode where the front and rear axles of a vehicle share the same instantaneous center of rotation. If the target steering mode is one where the front and rear axles of the corner module vehicle share the same instantaneous center of rotation—that is, a mode scenario entirely defined by the instantaneous center of rotation—then the second constraint condition is used as the target constraint condition. The second constraint condition includes the following:
[0090]
[0091] in, The first in the corner module vehicle The steering angle of each wheel; The first in the corner module vehicle The position of the wheel center; This is the position of the instantaneous center of rotation.
[0092] When transitioning from a stationary state to a specific mode, the steering angles of all four wheels converge to a defined value. During dynamic mode switching, safety must be considered to ensure that the wheel steering angle relationships meet pre-designed constraints, thereby guaranteeing driving stability before and after the mode switch. During mode switching, all four wheels maintain a unified instantaneous steering center constraint. This not only ensures reliable and coordinated changes in the steering angles of the four wheels but also prevents abrupt changes in vehicle motion during mode switching, even allowing for switching while maintaining yaw motion.
[0093] Specifically, when the vehicle is already in a U-turn mode and a rotational instantaneous center already exists, even if the mode changes, the rotation of the wheels must always maintain the rotational instantaneous center, and the wheel drive direction must remain unchanged. Therefore, it is possible to design a system where all four wheels simultaneously satisfy a single instantaneous center constraint, allowing the rotational instantaneous center to move along a trajectory that satisfies the target turning angle. However, simply changing the rotational instantaneous center along a straight line is insufficient, because when the rotational instantaneous center finally converges to a certain wheel position, it may not satisfy the final turning angle shape. For example... Figure 7As shown, a schematic diagram is presented where the instantaneous center of rotation changes along a straight line. Under such a trajectory, although the process constraints are guaranteed at all times, the pattern requirements of the endpoint are not met. Moreover, it is obvious that when the coordinates of the instantaneous center of rotation coincide with the coordinates of the wheel, the steering angle of the wheel cannot be constrained by the instantaneous center.
[0094] Therefore, this application uses a curve passing through the wheel's center of mass as the trajectory of the instantaneous rotation center during mode switching, where the wheel's center of mass refers to the centers of mass of multiple wheels of the corner module vehicle. Furthermore, to avoid the coordinates of the instantaneous rotation center coinciding with the wheel's coordinates, the coordinates of the starting and ending points are moved a preset distance inward from the vehicle, based on the wheel's coordinates. .like Figure 8 As shown, a schematic diagram illustrates how the instantaneous center of rotation changes along a curve.
[0095] In yet another possible implementation, such as Figure 9 The diagram illustrates a steering mode where the front and rear axles of a vehicle do not share the same instantaneous center of rotation. If the target steering mode is one with an instantaneous center of rotation, and the front and rear axles of the corner module vehicle do not share the same instantaneous center of rotation, then the third constraint condition is used as the target constraint condition; the third constraint condition includes the following:
[0096]
[0097] in, and The corner module vehicles are respectively the first The steering angle of the first front axle wheel and the first Steering angle of each rear axle wheel; and The corner module vehicles are respectively the first The wheel center position of the first front axle wheel and the first The position of the wheel center of each rear axle wheel; and These are the positions of the instantaneous center of rotation of the front axle and the rear axle, respectively.
[0098] In other words, in scenarios where the front and rear axles do not share a common instantaneous center, the front and rear axles will control the steering angle by following different instantaneous centers of rotation. In this scenario, the steering angle distribution of the four wheels is geometrically symmetrical. The instantaneous centers of the front and rear axles can be made to move simultaneously at the same speed in opposite directions along the centerline.
[0099] Specifically, the trajectory of the instantaneous center of rotation of the front axle during mode switching is a straight line moving along the first centerline in the first direction; the trajectory of the instantaneous center of rotation of the rear axle during mode switching is a straight line moving along the second centerline in the second direction; wherein, the first direction is opposite to the second direction; the first centerline is a straight line passing through the center points of the two front axle wheels in the corner module vehicle; the second centerline is a straight line passing through the center points of the two rear axle wheels in the corner module vehicle.
[0100] The speed at which the instantaneous center of rotation of the front axle moves can be defined as: The instantaneous speed at which the center of rotation of the rear axle moves is: .in, This is a parameter for adjustable speed.
[0101] Step 302: Determine the steering control torque of each wheel of the corner module vehicle according to the target constraints.
[0102] In one possible implementation, the steering angle of each wheel can be calculated in real time based on the target constraints. Based on the steering angle of each wheel and the dynamic equations, the steering control torque of each wheel can be calculated.
[0103] Specifically, for a single corner module, its control is achieved through a steering motor, a worm gear reducer, and a transmission mechanism, ultimately reaching the corner module's hub. The dynamic equations of the corner module steering system can be simplified as follows:
[0104]
[0105] in, It is the moment of inertia; Angular acceleration; ω is angular velocity; B is the damping coefficient; This is the frictional resistance torque; This is the restoring torque; This is the control force input for the steering system of this corner module.
[0106] The aforementioned constraints:
[0107] (1) Ackerman type, the steering angle of the front and rear axle wheels follows the steering angle of their respective reference wheels;
[0108]
[0109] (2) Instantaneous center type: The steering angle of the wheel is directly constrained by the coordinates of the instantaneous center of rotation.
[0110]
[0111] Its constraint expression is:
[0112]
[0113] in, , All are positive integers. To introduce the deviation, a deviation is set to ensure that the actual steering angle converges towards the constraint. .
[0114] According to the UK method, by changing the form of the constraint expressions and the dynamic equations, the constraint expressions can be transformed into:
[0115]
[0116] The unconstrained dynamic equations can be transformed into:
[0117]
[0118] Through the transformed constraint expressions and dynamic equations, we can obtain differential equations with the steering wheel angle or instantaneous center coordinates as independent variables.
[0119] The differential equation with the steering wheel angle as the independent variable is:
[0120]
[0121] The differential equation with the instantaneous center coordinates as the independent variable is:
[0122]
[0123] It should be noted that the standard mode and the diagonal mode are applicable to differential equations with the steering wheel angle as the independent variable, while other modes are applicable to differential equations with the instantaneous center coordinates as the independent variable.
[0124] Based on the above differential equation, the steering control torque for each wheel... ,in, .
[0125] Step 303: Control each wheel according to the steering control torque of each wheel to switch the control angle module vehicle from the current steering mode to the target steering mode.
[0126] After obtaining the steering control torque of each wheel, the steering control torque of each wheel is sent to the control device of each wheel. The control device controls the steering of the corresponding wheel based on the received steering control torque, thereby realizing the switching of the vehicle from the current steering mode to the target steering mode by the control angle module.
[0127] In addition, after the control angle module vehicle switches from the current steering mode to the bridge mode, it switches from the bridge mode to the target steering mode. The switching process at each stage is similar to the process of the control angle module vehicle switching from the current steering mode to the target steering mode, as described above, and will not be repeated here.
[0128] In addition, a simulation was conducted to demonstrate the switching process from stationary turning mode to U-shaped turning mode along the center point. The simulation results are as follows: Figure 10 As shown, it illustrates the curve of the wheel's steering angle changing over time during mode switching. It can be seen that the steering angle change is very smooth, demonstrating good following performance. Therefore, the steering mode switching method for vehicles based on the aforementioned angle module can guarantee complete reliability in each state during the switching process.
[0129] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages in other steps. It is understood that the steps in different embodiments can be freely combined as needed, and all non-contradictory solutions formed by such combinations are within the scope of protection of this application.
[0130] Based on the same inventive concept, this application also provides a steering mode switching device for a corner module vehicle to implement the steering mode switching method for the corner module vehicle described above. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations of one or more embodiments of the steering mode switching device for corner module vehicles provided below can be found in the limitations of the steering mode switching method for corner module vehicles described above, and will not be repeated here.
[0131] In one exemplary embodiment, such as Figure 11 As shown, a steering mode switching device for a corner module vehicle is provided. The steering mode switching device 1100 for a corner module vehicle includes: a receiving module 1101 and a control module 1102, wherein:
[0132] The receiving module 1101 is used to receive a mode switching instruction, which includes switching information for indicating the vehicle of the angle module to switch to the target steering mode;
[0133] The control module 1102 is used to query a pre-stored mode switching relationship table to determine whether the current steering mode of the corner module vehicle can be switched to the target steering mode. The mode switching relationship table includes the switching relationship between multiple steering modes. If yes, the control module vehicle switches from the current steering mode to the target steering mode. If no, the control module vehicle switches from the current steering mode to the bridge mode, and then controls the control module vehicle to switch from the bridge mode to the target steering mode.
[0134] In one embodiment, the corner module vehicle has multiple steering modes including standard mode, diagonal mode, ramp parking mode, lateral movement mode, U-turn mode, stationary turning mode, and U-turn mode along center point; the bridge mode includes standard mode and stationary turning mode.
[0135] In one embodiment, the switching relationships between multiple steering modes in the mode switching relationship table include at least one of the following:
[0136] The standard mode can be switched to any of the multiple steering modes other than the standard mode;
[0137] The stationary steering mode can be switched to any of the multiple steering modes except for the diagonal driving mode and the stationary steering mode.
[0138] The slant mode can be switched to the standard mode, but cannot be switched to any of the multiple steering modes other than the standard mode.
[0139] Both the U-shaped steering mode and the center-point U-shaped steering mode can be switched to the standard mode and the stationary steering mode, but neither can be switched to any other steering mode among the multiple steering modes other than the standard mode and the stationary steering mode;
[0140] The ramp parking mode can be switched to standard mode, lateral movement mode, and stationary turning mode, but cannot be switched to inclined mode, ramp parking mode, U-turn mode, or center point U-turn mode.
[0141] Lateral movement mode can be switched to standard mode, slope parking mode and stationary turning mode, but cannot be switched to diagonal mode, lateral movement mode, U-turn mode and center point U-turn mode.
[0142] In one embodiment, the control module 1102 is specifically configured to determine target constraints based on the type of the target steering mode; determine the steering control torque of each wheel of the corner module vehicle based on the target constraints; and control each wheel based on the steering control torque of each wheel to control the corner module vehicle to switch from the current steering mode to the target steering mode.
[0143] In one embodiment, the control module 1102 is specifically configured to use a first constraint as the target constraint if the target steering mode is of the type without an instantaneous center of rotation; the first constraint includes the following:
[0144]
[0145]
[0146]
[0147] in, , , These are the steering angles of the outer front wheel, the inner front wheel, and the reference front wheel of the angle module vehicle, respectively. , , These are the steering angles of the outer rear wheel, the inner rear wheel, and the reference rear wheel of the angle module vehicle, respectively. and These are the front and rear axle track widths of the corner module vehicle, respectively. This is the virtual wheelbase between the front axle reference wheel and the rear axle reference wheel; This represents the actual wheelbase between the front axle reference wheel and the rear axle reference wheel. It is the ratio of the steering angle of the rear axle reference wheel to the steering angle of the front axle reference wheel.
[0148] In one embodiment, the control module 1102 is specifically configured to use a second constraint as the target constraint if the target steering mode is one with an instantaneous center of rotation, and the front and rear axles of the corner module vehicle have the same instantaneous center of rotation; the second constraint includes the following:
[0149]
[0150] in, The first in the corner module vehicle The steering angle of each wheel; The first in the corner module vehicle The position of the wheel center; This is the position of the instantaneous center of rotation.
[0151] In one embodiment, the movement trajectory of the instantaneous center of rotation during the mode switching process is a curve passing through the center of mass of the wheel, which is the center of mass of multiple wheels of the corner module vehicle.
[0152] In one embodiment, the control module 1102 is specifically configured to use a third constraint as the target constraint if the target steering mode is one with an instantaneous center of rotation, and the front and rear axles of the corner module vehicle do not have the same instantaneous center of rotation; the third constraint includes the following:
[0153]
[0154] in, and The corner module vehicles are respectively the first The steering angle of the first front axle wheel and the first Steering angle of each rear axle wheel; and The corner module vehicles are respectively the first The wheel center position of the first front axle wheel and the first The position of the wheel center of each rear axle wheel; and These are the positions of the instantaneous center of rotation of the front axle and the rear axle, respectively.
[0155] In one embodiment, the trajectory of the instantaneous center of rotation of the front axle during mode switching is a straight line moving along the first centerline in the first direction; the trajectory of the instantaneous center of rotation of the rear axle during mode switching is a straight line moving along the second centerline in the second direction; wherein the first direction is opposite to the second direction; the first centerline is a straight line passing through the center points of the two front axle wheels in the corner module vehicle; the second centerline is a straight line passing through the center points of the two rear axle wheels in the corner module vehicle.
[0156] Each module in the steering mode switching device of the aforementioned corner module vehicle can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.
[0157] In one exemplary embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 12As shown, the computer device includes a processor, memory, input / output interface, communication interface, display unit, and input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interface. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The input / output interface is used for exchanging information between the processor and external devices. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, Near Field Communication (NFC), or other technologies. When executed by the processor, the computer program implements a steering mode switching method for a corner module vehicle. The display unit is used to form a visually visible image and can be a display screen, projection device, or virtual reality imaging device. The display screen can be an LCD screen or an e-ink screen. The input device of the computer device can be a touch layer covering the display screen, or buttons, trackballs, or touchpads set on the casing of the computer device, or external keyboards, touchpads, or mice, etc.
[0158] Those skilled in the art will understand that Figure 12 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.
[0159] In one exemplary embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method described in any of the above-described method embodiments.
[0160] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in any of the above method embodiments.
[0161] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps of the method described in any one of the above method embodiments.
[0162] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.
[0163] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.
[0164] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.
Claims
1. A method for safe switching control of steering modes in a corner module vehicle, characterized in that, The method includes: Receive a mode switching instruction, the mode switching instruction including switching information for instructing the corner module vehicle to switch to the target steering mode; The pre-stored mode switching relationship table is queried to determine whether the current steering mode of the corner module vehicle can be switched to the target steering mode; the mode switching relationship table includes the switching relationships between multiple steering modes of the corner module vehicle. If so, control the corner module vehicle to switch from the current steering mode to the target steering mode; If not, after controlling the corner module vehicle to switch from the current steering mode to the bridge mode, control the corner module vehicle to switch from the bridge mode to the target steering mode.
2. The method according to claim 1, characterized in that, The multiple steering modes of the corner module vehicle include standard mode, diagonal mode, slope parking mode, lateral movement mode, U-turn mode, stationary turning mode, and U-turn mode along the center point; the bridge mode includes the standard mode and the stationary turning mode.
3. The method according to claim 2, characterized in that, The switching relationships between multiple steering modes in the mode switching relationship table include at least one of the following: The standard mode can be switched to any of the multiple steering modes other than the standard mode; The stationary turning mode can be switched to any of the multiple turning modes other than the diagonal mode and the stationary turning mode; The diagonal driving mode can be switched to the standard mode, but cannot be switched to any other steering mode among the multiple steering modes except the standard mode; Both the U-shaped steering mode and the U-shaped steering mode along the center point can be switched to the standard mode and the stationary steering mode, but neither can be switched to any other steering mode among the multiple steering modes except the standard mode and the stationary steering mode; The ramp parking mode can be switched to the standard mode, the lateral movement mode, and the stationary turning mode, but cannot be switched to the inclined mode, the ramp parking mode, the U-turn mode, and the center point U-turn mode. The lateral movement mode can be switched to the standard mode, the slope parking mode, and the stationary turning mode, but cannot be switched to the diagonal mode, the lateral movement mode, the U-turn mode, and the center-point U-turn mode.
4. The method according to claim 1, characterized in that, The control of the corner module vehicle to switch from the current steering mode to the target steering mode includes: Determine the target constraints based on the type of the target steering mode; Based on the target constraints, determine the steering control torque of each wheel of the corner module vehicle; The steering control torque of each wheel is used to control the corner module vehicle to switch from the current steering mode to the target steering mode.
5. The method according to claim 4, characterized in that, The step of determining the target constraints based on the type of the target steering mode includes: If the target steering mode is a type that does not have an instantaneous center of rotation, then the first constraint condition shall be used as the target constraint condition. The first constraint includes the following: in, , , These are the steering angles of the outer front wheel, the inner front wheel, and the reference front wheel of the vehicle, respectively. , , These are the steering angles of the outer rear wheel, the inner rear wheel, and the reference rear wheel of the vehicle, respectively. and These are the front axle track and rear axle track of the corner module vehicle, respectively; This is the virtual wheelbase between the front axle reference wheel and the rear axle reference wheel; This represents the actual wheelbase between the front axle reference wheel and the rear axle reference wheel. It is the ratio of the steering angle of the rear axle reference wheel to the steering angle of the front axle reference wheel.
6. The method according to claim 4, characterized in that, The step of determining the target constraints based on the type of the target steering mode includes: If the target steering mode is one with an instantaneous center of rotation, and the front and rear axles of the corner module vehicle have the same instantaneous center of rotation, then the second constraint condition is used as the target constraint condition. The second constraint includes the following: in, The first of the corner module vehicles The steering angle of each wheel; The first of the corner module vehicles The position of the wheel center; This is the position of the instantaneous center of rotation.
7. The method according to claim 6, characterized in that, The trajectory of the instantaneous center of rotation during the mode switching process is a curve that passes through the center of mass of the wheel, where the center of mass of the wheel refers to the center of mass of multiple wheels of the corner module vehicle.
8. The method according to claim 4, characterized in that, The step of determining the target constraints based on the type of the target steering mode includes: If the target steering mode is one with an instantaneous center of rotation, and the front and rear axles of the corner module vehicle do not have the same instantaneous center of rotation, then the third constraint condition will be used as the target constraint condition. The third constraint includes the following: in, and The corner module vehicles are respectively the first The steering angle of the first front axle wheel and the first Steering angle of each rear axle wheel; and The corner module vehicles are respectively the first The wheel center position of the first front axle wheel and the first The position of the wheel center of each rear axle wheel; and These are the positions of the instantaneous center of rotation of the front axle and the rear axle, respectively.
9. The method according to claim 8, characterized in that, The trajectory of the instantaneous center of rotation of the front axle during the mode switching process is a straight line moving along the first center line in the first direction; the trajectory of the instantaneous center of rotation of the rear axle during the mode switching process is a straight line moving along the second center line in the second direction. Wherein, the first direction is opposite to the second direction; the first center line is a straight line passing through the center points of the two front axle wheels in the corner module vehicle; the second center line is a straight line passing through the center points of the two rear axle wheels in the corner module vehicle.
10. A steering mode switching device for a corner module vehicle, characterized in that, The device includes: A receiving module is used to receive a mode switching instruction, the mode switching instruction including switching information for instructing the corner module vehicle to switch to the target steering mode; The control module is used to query a pre-stored mode switching relationship table to determine whether the current steering mode of the corner module vehicle can be switched to the target steering mode; the mode switching relationship table includes the switching relationship between multiple steering modes of the corner module vehicle; if yes, the control module controls the corner module vehicle to switch from the current steering mode to the target steering mode; if no, the control module controls the corner module vehicle to switch from the current steering mode to the bridge mode, and then controls the corner module vehicle to switch from the bridge mode to the target steering mode.