A method, medium, and controller for maneuverability and stability coordination

Abstract

The present application belongs to the technical field of vehicle motion state control, and discloses a handling and stability coordination method, medium and controller. The method comprises the following steps: calculating a handling reference yaw angular velocity under a handling control target according to vehicle state parameters; calculating a stability reference yaw angular velocity under a stability control target according to vehicle state parameters; constructing a stability adjustment coefficient according to a mass side slip angle and a vehicle body roll angle; constructing a coordination reference yaw angular velocity according to the handling reference yaw angular velocity and the stability reference yaw angular velocity; and adjusting the weight of the handling reference yaw angular velocity and the stability reference yaw angular velocity in the coordination reference yaw angular velocity by using the stability adjustment coefficient. The present application simultaneously considers the influence of the mass side slip angle and the vehicle body roll angle on handling and stability, can take into account both stability and handling, and can meet the demand of different working conditions for stability or handling.

Description

Technical Field

[0001] This invention belongs to the field of vehicle motion state control technology, specifically relating to a method, medium, and controller for coordinating maneuverability and stability. Background Technology

[0002] Yaw rate refers to the speed at which a vehicle rotates around its vertical axis during cornering, and it is an important parameter describing the lateral motion of a vehicle when cornering. Yaw rate is also an important indicator for evaluating a vehicle's stability and handling.

[0003] Yaw rate can be controlled by adjusting parameters such as vehicle speed and steering angle. Yaw rate control relies on a reference value, calculated in real-time based on the control objective and driving conditions. The yaw rate is then controlled to follow the reference yaw rate to achieve the control objective.

[0004] Existing technologies design reference yaw rate algorithms with the control objective of improving maneuverability or stability, but challenges remain in coordinating and balancing maneuverability and stability objectives. Summary of the Invention

[0005] This application provides a method for balancing maneuverability and stability to address related technical problems.

[0006] This invention is achieved through the following technical solution: a method for coordinating maneuverability and stability, comprising the following steps:

[0007] Calculate the handling reference yaw rate under the handling control target based on vehicle state parameters;

[0008] Calculate the stability reference yaw rate under the stability control target based on vehicle state parameters;

[0009] A stability adjustment coefficient is constructed based on the center of gravity sideslip angle and the vehicle body roll angle;

[0010] A coordinated reference yaw rate is constructed based on the controllability reference yaw rate and the stability reference yaw rate;

[0011] The stability adjustment coefficient is used to adjust the weights of the maneuvering reference yaw rate and the stability reference yaw rate in the coordination reference yaw rate.

[0012] The coordinated reference yaw rate proposed in this invention includes both a handling reference yaw rate and a stability reference yaw rate, which is a prerequisite for balancing handling and stability. By adjusting the weights through a stability adjustment coefficient, the balance between handling and stability can be coordinated according to the vehicle's operating conditions. This allows for a balance between handling and stability under different operating conditions, while also emphasizing one aspect, thereby improving the driving experience.

[0013] Existing technologies neglect the impact of vehicle roll angle on stability and handling. This invention considers both the center of gravity sideslip angle and the vehicle roll angle when constructing the stability adjustment coefficient. The center of gravity sideslip angle directly affects the vehicle's stability and handling. However, the vehicle roll angle directly affects the distribution of the vehicle's vertical load, which in turn affects the lateral stiffness of the left and right wheels. The lateral stiffness, in turn, affects the center of gravity sideslip angle, thereby affecting stability and handling.

[0014] Furthermore, a handling reference yaw rate calculation model is established based on the system dynamics of the vehicle steering process. The vehicle state parameters used to calculate the handling yaw rate include longitudinal vehicle speed, wheelbase, stability factor, front wheel steering angle, and tire-road peak adhesion coefficient.

[0015] Furthermore, the stability factor is set to 0. Setting the stability factor to 0 sets the reference vehicle steering characteristics for the handling control target to neutral steering.

[0016] Furthermore, a stability reference yaw rate calculation model is established based on the control objective of suppressing the center of gravity sideslip angle, and the vehicle state parameters used to calculate the stability reference yaw rate include the stability yaw coefficient, lateral acceleration, and longitudinal vehicle speed.

[0017] Excessive or insufficient sideslip angle can cause a vehicle to lose stability. Therefore, when establishing a stability reference yaw rate calculation model, the sideslip angle should be suppressed to avoid being too large or too small in order to ensure stability.

[0018] Furthermore, the stability adjustment coefficient is used as a weighting coefficient for the stability reference yaw rate, and the difference between 1 and the stability adjustment coefficient is used as a weighting coefficient for the maneuverability reference yaw rate.

[0019] A larger stability adjustment coefficient results in a larger weighting coefficient for the stability reference yaw rate and a smaller weighting coefficient for the handling reference yaw rate, thus emphasizing improved stability. Conversely, a smaller stability adjustment coefficient results in a smaller weighting coefficient for the stability reference yaw rate and a larger weighting coefficient for the handling reference yaw rate, thus emphasizing improved handling.

[0020] Furthermore, the formula for calculating the coordinated reference yaw rate is as follows:

[0021] γ ref =(1-k) β )γ ref,h +k β γ ref,s

[0022] In the formula, γ ref k represents the coordinated reference yaw rate. β γ represents the stability adjustment coefficient. ref,h γ represents the control reference yaw rate. ref,s This indicates the stability yaw rate.

[0023] Furthermore, a two-dimensional fuzzy control rule is constructed based on the centroid sideslip angle and the vehicle body roll angle: the mapping relationship between the combination of fuzzy values ​​of the centroid sideslip angle and the vehicle body roll angle and the fuzzy value of the stability adjustment coefficient.

[0024] By inputting the fuzzy values ​​of the centroid sideslip angle and the vehicle body roll angle, and then outputting the corresponding fuzzy values ​​of the stability adjustment coefficient according to the two-dimensional fuzzy control rules, the system can effectively achieve the desired stability adjustment coefficient.

[0025] Furthermore, the fuzzy set of the centroid sideslip angle includes {VS,S,M,B,VB}, the fuzzy set of the vehicle body roll angle includes {VS,S,M,B,VB}, and the fuzzy set of the stability adjustment coefficient includes {VS,S,M,B,VB}, where VS represents a very small fuzzy value, S represents a small fuzzy value, M represents a moderate fuzzy value, B represents a large fuzzy value, and VB represents a very large fuzzy value.

[0026] A fuzzy set is a set of fuzzy values. The fuzzy sets of the centroid sideslip angle and the vehicle body roll angle each have 5 fuzzy values, which can be combined to form 25 fuzzy inputs, covering 25 working conditions.

[0027] Furthermore, when the fuzzy value of the vehicle body roll angle does not exceed S, the fuzzy value of the stability adjustment coefficient increases with the increase of the centroid sideslip angle, and does not exceed B.

[0028] When the fuzzy value of the body roll angle does not exceed S, the body roll angle is small, which belongs to the small lateral condition. Under the small lateral condition, the weight of the stability reference yaw rate is limited by limiting the stability adjustment coefficient to not exceed B. Then the weight of the handling reference yaw rate is larger, which can quickly follow the steering characteristics of the vehicle and improve the handling performance of the vehicle.

[0029] Furthermore, when the fuzzy value of the vehicle body roll angle is above M, the fuzzy value of the stability adjustment coefficient decreases as the center of gravity sideslip angle decreases, and is not lower than S.

[0030] When the fuzzy value of the vehicle roll angle is above M, the vehicle roll angle is large, which belongs to the large lateral condition. Under the large lateral condition, the stability reference yaw rate is given a large weight by limiting the stability adjustment coefficient to no less than S, so as to maintain the stability of the vehicle and prevent the vehicle from sideslipping and becoming unstable.

[0031] The present invention also provides a computer-readable storage medium storing at least one instruction, which is loaded and executed by a processor to implement the above-described method for coordinating operability and stability.

[0032] The present invention also provides a controller comprising the computer-readable storage medium described above.

[0033] This invention considers the influence of the center of gravity sideslip angle and the vehicle body roll angle on handling and stability. Based on the center of gravity sideslip angle and the vehicle body roll angle, a two-dimensional fuzzy control rule is constructed to cover multiple operating conditions. The stability adjustment coefficient under different operating conditions is obtained to adjust the weight of the handling reference yaw rate and the stability reference yaw rate. This can take into account both stability and handling, and meet the emphasis requirements of different operating conditions on either stability or handling. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is a flowchart of the method for coordinating maneuverability and stability in this specific embodiment;

[0036] Figure 2 This is a schematic diagram of the sideslip angle and yaw rate of the center of mass;

[0037] Figure 3 This is a diagram showing the vehicle's roll angle. Detailed Implementation

[0038] Existing technologies design reference yaw rate algorithms with the control objective of improving maneuverability or stability, but challenges remain in coordinating and balancing maneuverability and stability objectives.

[0039] refer to Figure 1 As shown, in order to balance maneuverability and stability under different operating conditions, this specific embodiment provides a method for coordinating maneuverability and stability, including the following steps:

[0040] Calculate the handling reference yaw rate under the handling control target based on vehicle state parameters;

[0041] Calculate the stability reference yaw rate under the stability control target based on vehicle state parameters;

[0042] A stability adjustment coefficient is constructed based on the center of gravity sideslip angle and the vehicle body roll angle;

[0043] A coordinated reference yaw rate is constructed based on the controllability reference yaw rate and the stability reference yaw rate;

[0044] The stability adjustment coefficient is used to adjust the weights of the maneuvering reference yaw rate and the stability reference yaw rate in the coordination reference yaw rate.

[0045] refer to Figure 2 As shown, the sideslip angle is the angle β between the vehicle's velocity direction and its longitudinal axis, and the yaw rate is the angular velocity γ of the vehicle's circular motion around its Z-axis.

[0046] refer to Figure 3 As shown, when a car makes a sharp turn at a certain speed, the car body will tilt due to the centrifugal force, presenting an attitude where the inside is higher and the outside is lower. The angle between this car body and the ground is defined as the body roll angle, which is numerically equal to the angle φ between the car body and the z-axis.

[0047] The coordinated reference yaw rate proposed in this invention includes both a handling reference yaw rate and a stability reference yaw rate, which is a prerequisite for balancing handling and stability. By adjusting the weights through a stability adjustment coefficient, the balance between handling and stability can be coordinated according to the vehicle's operating conditions. This allows for a balance between handling and stability under different operating conditions, or an emphasis on one aspect, thereby improving the driving experience.

[0048] The sideslip angle directly affects vehicle stability and handling, while the body roll angle directly affects the distribution of the vehicle's vertical load. The distribution of the vertical load affects the lateral stiffness of the left and right wheels, which in turn affects the sideslip angle, thus impacting stability and handling. However, existing technologies neglect the influence of body roll angle on stability and handling. This specific implementation considers both the sideslip angle and body roll angle when constructing the stability adjustment coefficient, significantly improving vehicle handling performance under complex conditions and further enhancing the driving experience.

[0049] Example 1

[0050] This embodiment describes the calculation model for the reference yaw rate and the calculation model for the stability reference yaw rate.

[0051] In this embodiment, a handling reference yaw rate calculation model is established based on the system dynamics of the vehicle steering process. The vehicle state parameters used to calculate the handling yaw rate include longitudinal vehicle speed, wheelbase, stability factor, front wheel angle, and tire-road peak adhesion coefficient.

[0052] The reference yaw rate calculation model is as follows:

[0053]

[0054] Where, γ ref,h The yaw rate is used as a controllable reference; v x Let l be the longitudinal speed of the vehicle; l be the wheelbase of the vehicle; K be the stability factor; and δ be the longitudinal speed of the vehicle. f The front wheel steering angle of the vehicle; μ is the peak tire-road adhesion coefficient; i s This is the calibration coefficient, with a value range of 0.5 to 1.

[0055] Preferably, the stability factor K is set to 0. Setting the stability factor to 0 sets the reference vehicle steering characteristics for the handling control target to neutral steering.

[0056] In this embodiment, a stability reference yaw rate calculation model is established based on the control objective of suppressing the center of gravity sideslip angle, and the vehicle state parameters used to calculate the stability reference yaw rate include the stability yaw coefficient, lateral acceleration, and longitudinal vehicle speed.

[0057] The stability reference yaw rate calculation model is as follows:

[0058]

[0059] Where, γ ref,s For stability reference yaw rate; k γ,s a is the stability yaw coefficient; y v is the lateral acceleration of the vehicle. x This represents the vehicle's longitudinal speed.

[0060] Excessive or insufficient sideslip angle can cause a vehicle to lose stability. Therefore, when establishing a stability reference yaw rate calculation model, the sideslip angle should be suppressed to avoid being too large or too small in order to ensure stability.

[0061] Example 2

[0062] This embodiment provides a detailed explanation of the adjustment weight for the stability adjustment coefficient.

[0063] In this embodiment, the stability adjustment coefficient is used as a weighting coefficient for the stability reference yaw rate, and the difference between 1 and the stability adjustment coefficient is used as a weighting coefficient for the maneuverability reference yaw rate.

[0064] A larger stability adjustment coefficient results in a larger weighting coefficient for the stability reference yaw rate and a smaller weighting coefficient for the handling reference yaw rate, thus emphasizing improved stability. Conversely, a smaller stability adjustment coefficient results in a smaller weighting coefficient for the stability reference yaw rate and a larger weighting coefficient for the handling reference yaw rate, thus emphasizing improved handling.

[0065] In this embodiment, the formula for calculating the coordinated reference yaw rate is as follows:

[0066] γ ref =(1-k) β )γ ref,h +k β γ ref,s

[0067] In the formula, γ ref k represents the coordinated reference yaw rate. β γ represents the stability adjustment coefficient. ref,h γ represents the control reference yaw rate. ref,s This indicates the stability yaw rate.

[0068] Example 3

[0069] This embodiment provides a detailed explanation of how to construct the stability adjustment coefficient.

[0070] In this embodiment, a two-dimensional fuzzy control rule is constructed based on the centroid sideslip angle and the vehicle body roll angle: the mapping relationship between the combination of fuzzy values ​​of the centroid sideslip angle and the vehicle body roll angle and the fuzzy value of the stability adjustment coefficient.

[0071] By inputting the fuzzy values ​​of the centroid sideslip angle and the vehicle body roll angle, and then outputting the corresponding fuzzy values ​​of the stability adjustment coefficient according to the two-dimensional fuzzy control rules, the system can effectively achieve the desired stability adjustment coefficient.

[0072] In this embodiment, the fuzzy set of the centroid sideslip angle includes {VS,S,M,B,VB}, the fuzzy set of the vehicle body roll angle includes {VS,S,M,B,VB}, and the fuzzy set of the stability adjustment coefficient includes {VS,S,M,B,VB}, where VS represents a very small fuzzy value, S represents a small fuzzy value, M represents a moderate fuzzy value, B represents a large fuzzy value, and VB represents a very large fuzzy value.

[0073] A fuzzy set is a set of fuzzy values. The fuzzy sets of the centroid sideslip angle and the vehicle body roll angle each have 5 fuzzy values, which can be combined to form 25 fuzzy inputs, covering 25 working conditions.

[0074] In this embodiment, when the fuzzy value of the vehicle body roll angle does not exceed S, the fuzzy value of the stability adjustment coefficient increases with the increase of the centroid sideslip angle, and does not exceed B.

[0075] When the fuzzy value of the body roll angle does not exceed S, the body roll angle is small, which belongs to the small lateral condition. Under the small lateral condition, the weight of the stability reference yaw rate is limited by limiting the stability adjustment coefficient to not exceed B. Then the weight of the handling reference yaw rate is larger, which can quickly follow the steering characteristics of the vehicle and improve the handling performance of the vehicle.

[0076] In this embodiment, when the fuzzy value of the vehicle body roll angle is above M, the fuzzy value of the stability adjustment coefficient decreases as the center of gravity sideslip angle decreases, and is not lower than S.

[0077] When the fuzzy value of the vehicle roll angle is above M, the vehicle roll angle is large, which belongs to the large lateral condition. Under the large lateral condition, the stability reference yaw rate is given a large weight by limiting the stability adjustment coefficient to no less than S, so as to maintain the stability of the vehicle and prevent the vehicle from sideslipping and becoming unstable.

[0078] Specifically, the two-dimensional fuzzy control rules are as follows:

[0079] Table 1

[0080]

[0081] The center of gravity sideslip angle signal X1 and the vehicle body roll angle signal X2 can be acquired by sensors, such as inertial measurement units and inertial navigation measurement units, or estimated by IMU.

[0082] The center of gravity sideslip angle signal, vehicle body roll angle signal, and stability adjustment coefficient are all fuzzified and used as inputs for fuzzy control.

[0083] Specifically, the input variables are defined as the center of gravity sideslip angle signal X1 and the vehicle body roll angle signal X2. The value range of the center of gravity sideslip angle signal X1 is 0-8 (deg), and the value range of the vehicle body roll angle signal X2 is 0-30 (deg). The output is defined as the stability adjustment coefficient Y. The value range of Y is 0-1.

[0084] The centroid sideslip angle signal X1 is fuzzified to obtain five fuzzy sets {VS, S, M, B, VB}, with a universe of discourse of 0–4 and a trapezoidal membership function. Here, VS represents a very small centroid sideslip angle, S represents a small centroid sideslip angle, M represents a moderate centroid sideslip angle, B represents a large centroid sideslip angle, and VB represents a very large centroid sideslip angle.

[0085] The vehicle roll angle signal X2 is fuzzified to obtain five fuzzy sets {VS, S, M, B, VB}, with a universe of discourse of 0–4 and a trapezoidal membership function. Here, VS represents a very small roll angle, S represents a small roll angle, M represents a moderate roll angle, B represents a large roll angle, and VB represents a very large roll angle.

[0086] The stability adjustment coefficient Y is fuzzified to obtain five fuzzy sets {VS, S, M, B, VB}, with a universe of discourse of 0–4 and a trapezoidal membership function. Here, VS represents a very small stability adjustment coefficient, S represents a small stability adjustment coefficient, M represents a moderate stability adjustment coefficient, B represents a large stability adjustment coefficient, and VB represents a very large stability adjustment coefficient.

[0087] First, the acquired centroid sideslip angle signal and vehicle body roll angle signal are converted into corresponding fuzzy values, and then the fuzzy value of the stability adjustment coefficient is determined by referring to Table 1 above.

[0088] The fuzzy values ​​of the stability adjustment coefficients are defuzzified, that is, converted into an actual value k through the inverse mapping of the output membership function of the stability adjustment coefficients. β .

[0089] Finally, the reference yaw rate is calculated using the formula for coordinating the reference yaw rate:

[0090] γ ref =(1-k) β )γ ref,h +k β γ ref,s

[0091] In the formula, γ ref k represents the coordinated reference yaw rate. β γ represents the stability adjustment coefficient. ref,h γ represents the control reference yaw rate. ref,s This indicates the stability yaw rate.

[0092] Example 4

[0093] This embodiment provides a computer-readable storage medium storing at least one instruction, which is loaded and executed by a processor to implement a maneuverability and stability coordination method. The maneuverability and stability coordination method in this embodiment includes any one of the methods in Embodiments 1 to 3, or all of the methods in Embodiments 1 to 3.

[0094] This embodiment also provides a controller, including the computer-readable storage medium described above.

[0095] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A method for coordinating maneuverability and stability, characterized in that, Includes the following steps: Calculate the handling reference yaw rate under the handling control target based on vehicle state parameters; Calculate the stability reference yaw rate under the stability control target based on vehicle state parameters; A stability adjustment coefficient is constructed based on the center of gravity sideslip angle and the vehicle body roll angle; A coordinated reference yaw rate is constructed based on the controllability reference yaw rate and the stability reference yaw rate; The stability adjustment coefficient is used to adjust the weights of the maneuvering reference yaw rate and the stability reference yaw rate in the coordination reference yaw rate.

2. The method for coordinating maneuverability and stability according to claim 1, characterized in that, A handling reference yaw rate calculation model is established based on the system dynamics of the vehicle steering process. The vehicle state parameters used to calculate the handling yaw rate include longitudinal vehicle speed, wheelbase, stability factor, front wheel steering angle, and tire-road peak adhesion coefficient.

3. The method for coordinating maneuverability and stability according to claim 2, characterized in that, The stability factor is set to 0.

4. The method for coordinating maneuverability and stability according to claim 1, characterized in that, A stability reference yaw rate calculation model is established based on the control objective of suppressing the center of gravity sideslip angle. The vehicle state parameters used to calculate the stability reference yaw rate include the stability yaw coefficient, lateral acceleration, and longitudinal vehicle speed.

5. The method for coordinating maneuverability and stability according to any one of claims 1 to 4, characterized in that, The stability adjustment coefficient is used as a weighting coefficient for the stability reference yaw rate, and the difference between 1 and the stability adjustment coefficient is used as a weighting coefficient for the maneuverability reference yaw rate.

6. The method for coordinating maneuverability and stability according to claim 5, characterized in that, The formula for calculating the coordinated reference yaw rate is as follows: c ref =(1-k β )c ref,h +k β c ref,s In the formula, γ ref k represents the coordinated reference yaw rate. β γ represents the stability adjustment coefficient. ref,h γ represents the control reference yaw rate. ref,s This indicates the stability yaw rate.

7. The method for coordinating maneuverability and stability according to claim 5, characterized in that, A two-dimensional fuzzy control rule is constructed based on the centroid sideslip angle and the vehicle body roll angle: the mapping relationship between the combination of fuzzy values ​​of the centroid sideslip angle and the vehicle body roll angle and the fuzzy value of the stability adjustment coefficient.

8. The method for coordinating maneuverability and stability according to claim 5, characterized in that, The fuzzy set of the centroid sideslip angle includes {VS,S,M,B,VB}, the fuzzy set of the vehicle body roll angle includes {VS,S,M,B,VB}, and the fuzzy set of the stability adjustment coefficient includes {VS,S,M,B,VB}, where VS represents a very small fuzzy value, S represents a small fuzzy value, M represents a moderate fuzzy value, B represents a large fuzzy value, and VB represents a very large fuzzy value.

9. The method for coordinating maneuverability and stability according to claim 8, characterized in that, When the fuzzy value of the vehicle body roll angle does not exceed S, the fuzzy value of the stability adjustment coefficient increases with the increase of the centroid sideslip angle, and does not exceed B.

10. The method for coordinating maneuverability and stability according to claim 8, characterized in that, When the fuzzy value of the vehicle body roll angle is above M, the fuzzy value of the stability adjustment coefficient decreases as the center of gravity sideslip angle decreases, and is not lower than S.

11. A computer-readable storage medium, characterized in that, The storage medium stores at least one instruction, which is loaded and executed by a processor to implement the maneuverability and stability coordination method as described in any one of claims 1 to 9.

12. A controller, characterized in that, Includes the computer-readable storage medium as described in claim 10.

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