A method and system for adjusting vehicle steering characteristics

Abstract

The present invention relates to a vehicle steering characteristic adjustment method and system, the method comprising the following steps: obtaining vehicle wheel load data, and using the wheel load data to calculate the current steering characteristic of the vehicle; obtaining the target steering characteristic of the vehicle, comparing the current steering characteristic with the target steering characteristic, and obtaining the target load transfer amount W; calculating the target stiffness of the anti-roll bar according to the corresponding relationship between the load transfer amount and the stiffness of the anti-roll bar; and adjusting the stiffness of the anti-roll bar based on the target stiffness so that the transferred load amount is the load transfer amount W. Compared with the prior art, the present invention uses wheel load data as input, and adjusts the front and rear axle load ratio parameters by adjusting the stiffness of the anti-roll bar to control the steering characteristic of the vehicle, and proposes a newer control strategy, and the wheel load input is more direct and can better reflect the motion characteristics of the vehicle.

Description

Technical Field

[0001] The present invention relates to the field of vehicle control technology, and in particular to a vehicle steering characteristic adjustment method and system. Background Art

[0002] The steering characteristics of a vehicle are important indicators of its handling performance. The parameters that affect its performance include the front and rear axle load ratio, tire stiffness, suspension stiffness, damper damping, etc. The adjustment of the vehicle's steering characteristics also mainly depends on the monitoring and adjustment of the above parameters.

[0003] Steering characteristics are divided into understeering and oversteering. Understeering is characterized by the fact that when the steering wheel angle is fixed, the turning radius of the vehicle increases with the increase of vehicle speed, and the corresponding front axle slip angle is greater than the rear axle slip angle. At this time, although the vehicle loses some steering ability, it is controllable and in a stable state; while oversteering is the opposite, the turning radius decreases with the increase of vehicle speed, and the vehicle is uncontrollable and in an unstable state.

[0004] For commercial vehicles with a high center of gravity, the design goal is to reduce the body tilt angle when turning to prevent serious accidents such as vehicle rollover. In racing cars and high-performance cars, maintaining a slight oversteer when turning can improve the steering sensitivity of the vehicle, and adjusting to a slight understeer when turning at high speeds can ensure vehicle stability, which is particularly important for improving the driving experience. In some other working conditions, such as when a large truck is driving on a road with poor road conditions, the effectiveness of its steering system can be guaranteed by controlling the steering characteristics, thereby improving safety.

[0005] However, the current adjustments to steering characteristics are mostly targeted at parameters such as tire stiffness, suspension stiffness, and damper damping, while there are few studies on adjusting steering characteristics based on the front and rear axle load ratio. Summary of the invention

[0006] The purpose of the present invention is to provide a vehicle steering characteristics adjustment method and system in order to overcome the defects of the above-mentioned prior art.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] According to a first aspect of the present invention, there is provided a method for adjusting vehicle steering characteristics, comprising the following steps:

[0009] S1. Obtaining wheel load data of the vehicle, and using the wheel load data to calculate the current steering characteristics of the vehicle;

[0010] S2. Obtain the target steering characteristic of the vehicle, compare the current steering characteristic with the target steering characteristic, and obtain the required load transfer amount W;

[0011] S3, calculating the target stiffness of the anti-roll bar according to the corresponding relationship between the load transfer amount and the stiffness of the anti-roll bar;

[0012] S4. Adjust the stiffness of the anti-roll bar based on the target stiffness so that the transferred load amount is the load transfer amount W obtained in the above step S2.

[0013] Furthermore, the vehicle wheel load data includes the front axle load and the rear axle load, and the calculation formula of the current steering characteristic is:

[0014]

[0015] Among them, G f is the front axle load, G r is the rear axle load, C αf is the cornering stiffness of the front wheel, C αr is the cornering stiffness of the rear wheel.

[0016] Furthermore, the current steering characteristic is compared with the target steering characteristic to obtain the load transfer amount W, which is specifically:

[0017] Conduct multiple tests in advance to obtain the load transfer amount W corresponding to the target steering characteristics with different values ​​of the current steering characteristics, store them in the vehicle controller, obtain the current steering characteristics and the target steering characteristics, and obtain the load transfer amount W by looking up the table.

[0018] Furthermore, the corresponding relationship between the load transfer amount and the anti-roll bar stiffness is:

[0019]

[0020] Where, ΔW a represents the calculated axle load transfer, which is determined based on the load transfer W and the calculated axis, where the calculated axis is the axis where the anti-roll bar is located. represents the front axle roll stiffness, Represents the rear axle roll stiffness, W s represents the sprung mass, t represents the calculated axle track, L represents the wheelbase, A y represents lateral acceleration / acceleration due to gravity, h s The distance from the center of mass of the sprung mass to the roll center, Z RC represents the roll center height, x represents the distance from the calculation axis to the center of mass, W ua is the unsprung mass, Z ua is the height of the center of mass of the unsprung mass, represents the calculated axle roll stiffness, the calculated axle lateral stiffness There is a corresponding relationship with the anti-roll bar stiffness.

[0021] Furthermore, in step S4, the target stiffness of the anti-roll bar is adjusted using closed-loop feedback, specifically:

[0022] 1) Adjust the stiffness of the anti-roll bar to the target stiffness;

[0023] 2) Obtain the real-time wheel load data of the vehicle and calculate the actual load transfer;

[0024] 3) According to the difference between the actual load transfer amount and the expected load transfer amount W, the target stiffness of the anti-roll bar is calculated through the corresponding relationship between the load transfer amount and the stiffness of the anti-roll bar;

[0025] 4) Repeat step 1) until the termination condition is met.

[0026] Furthermore, the termination condition is: the difference between the actual load transfer amount and the expected load transfer amount W is less than a preset deviation threshold, or the execution time of step S4 exceeds a preset time threshold.

[0027] According to a second aspect of the present invention, there is provided a vehicle steering characteristic adjustment system, comprising:

[0028] Wheel load determination module, used to obtain vehicle wheel load data;

[0029] A steering characteristic calculation module, used to calculate the current steering characteristic of the vehicle using the wheel load data;

[0030] A load transfer amount calculation module is used to obtain the target steering characteristic of the vehicle, compare the current steering characteristic with the target steering characteristic, and obtain the load transfer amount W;

[0031] A stiffness calculation module, used for calculating the target stiffness of the anti-roll bar according to the corresponding relationship between the load transfer amount and the stiffness of the anti-roll bar;

[0032] The adjustment module is used to adjust the stiffness of the anti-roll bar based on the target stiffness so that the transferred load amount is the load transfer amount W obtained above.

[0033] Furthermore, the vehicle wheel load data includes the front axle load and the rear axle load, and the calculation formula of the current steering characteristic is:

[0034]

[0035] Among them, G f is the front axle load, G r is the rear axle load, C αf is the cornering stiffness of the front wheel, C αr is the cornering stiffness of the rear wheel.

[0036] Furthermore, the corresponding relationship between the load transfer amount and the anti-roll bar stiffness is:

[0037]

[0038] Where, ΔW a represents the calculated axle load transfer, which is determined based on the load transfer W and the calculated axis, where the calculated axis is the axis where the anti-roll bar is located. represents the front axle roll stiffness, Represents the rear axle roll stiffness, W s represents the sprung mass, t represents the calculated axle track, L represents the wheelbase, A y represents lateral acceleration / acceleration due to gravity, h s The distance from the center of mass of the sprung mass to the roll center, Z RC represents the roll center height, x represents the distance from the calculation axis to the center of mass, W ua is the unsprung mass, Z ua is the height of the center of mass of the unsprung mass, represents the calculated axle roll stiffness, the calculated axle lateral stiffness There is a corresponding relationship with the anti-roll bar stiffness.

[0039] Furthermore, the regulation module uses closed-loop feedback to adjust the target stiffness of the anti-roll bar, specifically:

[0040] 1) Adjust the stiffness of the anti-roll bar to the target stiffness;

[0041] 2) Obtain the real-time wheel load data of the vehicle and calculate the actual load transfer;

[0042] 3) According to the difference between the actual load transfer amount and the expected load transfer amount W, the target stiffness of the anti-roll bar is calculated through the corresponding relationship between the load transfer amount and the stiffness of the anti-roll bar;

[0043] 4) Repeat step 1) until the termination condition is met.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] (1) Using wheel load data as input, the front and rear axle load ratio parameters are adjusted by adjusting the anti-roll bar stiffness to control the steering characteristics of the vehicle. A new control strategy is proposed, and the wheel load input is more direct and can better reflect the vehicle's motion characteristics.

[0046] (2) The control of the anti-roll bar in the prior art is mainly used to control the vehicle roll, while the control of the anti-roll bar in the present application is used to control the vehicle steering characteristics. Controlling understeer is more conducive to vehicle control, because roll pays more attention to the riding experience of the occupants and thus sacrifices some feedback of vehicle control, while understeer is easier for the driver to perceive and is more likely to serve as a safety warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A schematic flow chart of a method for adjusting vehicle steering characteristics;

[0048] Figure 2 It is a schematic diagram of the geometric relationship when the vehicle turns;

[0049] Figure 3 This is a simplified connection diagram between the vehicle and the anti-roll bar;

[0050] Figure 4 It is a closed-loop control flow chart;

[0051] Figure 5 The schematic diagram of tire cornering stiffness when vertical loads are redistributed between left and right wheels;

[0052] Figure numerals: 1. anti-roll bar, 2. vehicle suspension system, 3. system control unit. DETAILED DESCRIPTION

[0053] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given. Obviously, the described embodiment is only an embodiment of a part of the present invention, not all embodiments, and the protection scope of the present invention is not limited to the following embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0054] As used herein, "one embodiment" or "embodiment" refers to a particular feature, structure, or characteristic that may be included in at least one implementation of the invention. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to the process, method, product, or apparatus.

[0055] This specification provides method operation steps such as embodiments or flowcharts, but more or fewer operation steps may be included based on conventional or non-creative labor. The order of steps listed in the embodiments is only one way of executing the order of many steps and does not represent the only execution order. When the actual system or server product is executed, it can be executed in sequence or in parallel (for example, in a parallel processor or multi-threaded processing environment) according to the method shown in the embodiments or the drawings, or the execution order of steps without timing restrictions can be adjusted.

[0056] The electronically controlled lateral stability control device is referred to as the "anti-roll bar". It is a spring steel bar with a certain torsional stiffness, which is connected to the suspension knuckles or columns on both sides, and is used to provide a certain function of suppressing the relative movement of the coaxial wheels on both sides. The current research and design goals of active anti-roll bars for passenger cars are mainly focused on reducing the vibration felt by the occupants in the car, that is, reducing the stiffness of the anti-roll bar according to the bumpy road conditions, reducing the bump transmission from one wheel to the other side; or reducing the roll of the car body when turning, reducing the discomfort of the occupants.

[0057] The current research status of related technologies at home and abroad is as follows:

[0058] The active anti-roll bar technology used commercially abroad mainly includes the Porsche PDCC system: the planetary gear is driven by a 48V power supply to make the lateral stabilizer bar produce an initial rotation angle, control the ride stiffness, and cooperate with the air spring to formulate a suitable suspension bias frequency for the road spectrum of the vehicle. Domestic researchers have also conducted in-depth research on active anti-roll bar technology. There is a harmonic gear anti-roll bar that controls the speed and output torque of the DC motor to make the left and right stabilizer half-bars produce different degrees of relative torsion, generate different anti-roll torques, and control the size of the vehicle's roll angle. These systems have many advantages, but the disadvantages are: 1. High energy consumption, difficult to power with a low-voltage power supply on the vehicle. 2. High processing precision is required, the cost is high, and it is difficult to use in ordinary passenger cars. 3. It is heavy and occupies a lot of space. Because of its large number of gears and complex structure, it is difficult to achieve lightweight, which will lead to a significant increase in vehicle weight and reduce vehicle speed and maneuverability.

[0059] The above domestic and foreign anti-roll bar patents mainly focus on the design of the structure to improve the overall efficiency and stability of the structure. The control method of the above anti-roll bar is mainly to use the roll angle of the vehicle as the input variable and the torque of the motor as the output variable, which ultimately affects the roll angle to form feedback and achieve the purpose of reducing the vehicle roll.

[0060] In fact, by adjusting the stiffness of the anti-roll bar, the distribution of the load transfer between the front and rear axles can be changed while keeping the total amount of steady-state lateral load transfer unchanged, so as to change the steering characteristics of the vehicle. However, the existing roll angle method is not sufficient to derive the front and rear load transfer of the vehicle, so this logical control cannot be performed. In addition, in the prior art, the research on the anti-roll bar focuses more on the riding experience of the occupants, and there is no research on adjusting the front and rear axle load ratio by adjusting the anti-roll bar stiffness to adjust the vehicle's steering characteristics. In the previous research, the inventor proposed a dynamic wheel load measurement scheme, see Chinese patent application CN2022103883415 "A dynamic wheel load measurement and driving safety assistance system for automobiles", which provides technical support for the measurement of load transfer. In the actual driving of vehicles such as racing cars, sports cars, off-road vehicles or SUVs, engineering vehicles, etc., the requirements for steering characteristics are higher than the riding experience. Therefore, it is feasible to adjust the front and rear axle load ratio by adjusting the anti-roll bar stiffness to adjust the vehicle's steering characteristics and has a certain application market.

[0061] First, define the understeer degree K:

[0062]

[0063] Among them, G f is the front axle load, G r is the rear axle load, which can be obtained through the dynamic wheel load measurement system, C αf The cornering stiffness of the front wheel is a fixed parameter of the vehicle itself, C αr The cornering stiffness of the rear wheel is a known parameter;

[0064] In a simplified two-degree-of-freedom model of vehicle steering, such as Figure 2 As shown, let θ be the acute angle of the vertical lines of the front and rear wheel speeds, that is, the angle of the line connecting the steering center to the front and rear wheels, that is, the outer wheel turning angle of the vehicle. According to the geometric relationship, we can get:

[0065]

[0066] Among them, L is the wheelbase, R is the turning radius, a is the distance from the center of mass of the vehicle to the front wheel, b is the distance from the center of mass of the vehicle to the rear wheel, αf is the front slip angle, αr is the rear slip angle, and δ is the front wheel turning angle.

[0067] According to the tire cornering characteristics, the relationship between cornering force and slip angle can be calculated:

[0068] F y =C α ×α

[0069] The final expression of the front wheel turning angle is:

[0070]

[0071] Where V is the vehicle speed.

[0072] The steering characteristics of a vehicle can be reflected by the front wheel steering angle δ, turning radius R, etc. When the front wheel steering angle of the vehicle is greater than the angle between the speed direction and the longitudinal direction of the vehicle body, the steering characteristic of the vehicle is understeering. When the front wheel steering angle of the vehicle is less than the angle between the speed direction and the longitudinal direction of the vehicle body, the steering characteristic of the vehicle is oversteering. At the same time, according to the relationship between the tire side slip force and the sideslip angle, it can be seen that the understeering degree of the vehicle directly affects the force on the vehicle and the wear of the tire components. Therefore, the study of steering characteristics is not only related to the comfort of the passengers, but also to the design and maintenance of vehicle components. It is of great significance. It can be seen that in the above expression of the front wheel steering angle This is an important factor affecting the steering angle, that is, the understeering degree. f and G r It can be obtained through the dynamic wheel load measurement system, and other variables are the design parameters or basic motion parameters of the vehicle, which can be measured by relevant sensors. Therefore, the understeer degree K can be calculated using wheel load data to represent the current steering characteristics of the vehicle.

[0073] The theoretical basis of the present invention is:

[0074] The understeering characteristic of a vehicle is an important indicator of its handling performance. The parameters that affect its performance include the front and rear axle load ratio, tire stiffness, suspension stiffness, damper damping, etc. The adjustment of the vehicle's steering characteristics also mainly depends on the monitoring and adjustment of the above parameters.

[0075] Steering characteristics are divided into understeering and oversteering. Understeering is characterized by the fact that when the steering wheel angle is fixed, the turning radius of the vehicle increases with the increase of vehicle speed, and the corresponding front axle slip angle is greater than the rear axle slip angle. At this time, although the vehicle loses some steering ability, it is controllable and in a stable state; while oversteering is the opposite, the turning radius decreases with the increase of vehicle speed, and the vehicle is uncontrollable and in an unstable state.

[0076] The core idea of ​​the present invention is to use wheel load data, that is, front and rear axle load data (or further calculate the front and rear axle load ratio) as input to calculate the understeer degree of the vehicle, and then adjust the electronically controlled lateral stabilizer (that is, anti-roll bar) according to the deviation between the current understeer degree and the target understeer degree to change the roll stiffness of the vehicle, thereby achieving the purpose of adjusting the steering characteristics.

[0077] Here is an explanation of the specific relationship between roll stiffness and understeer: the greater the roll stiffness of the suspension (that is, the greater the force required to roll at the same angle), the more obvious the change in road load on the tire. When the vertical load on the left and right wheels is redistributed, the tire's lateral stiffness is as follows: Figure 5As shown in the figure, the average cornering stiffness of the tire will decrease, so in order to achieve the same cornering force, the slip angle will be larger, which is manifested as understeering. This application adjusts the load change by changing the roll stiffness, and the steering characteristics can be changed according to this graph relationship.

[0078] Specifically, the present invention provides a method for adjusting vehicle steering characteristics, such as Figure 1 As shown, the following steps are included:

[0079] S1. Obtaining vehicle wheel load data, and using the wheel load data to calculate the current steering characteristics of the vehicle;

[0080] The vehicle wheel load data includes the front axle load and the rear axle load. The calculation formula for the current steering characteristics is:

[0081]

[0082] Among them, G f is the front axle load, G r is the rear axle load, C αf is the cornering stiffness of the front wheel, C αr is the cornering stiffness of the rear wheel.

[0083] S2. Obtain the target steering characteristic of the vehicle, compare the current steering characteristic with the target steering characteristic, and obtain the required load transfer amount W;

[0084] Due to the differences in characteristics of different tires and the complexity and variability of the tire rubber structure, it is difficult to directly obtain an analytical expression between the steering characteristics and the load transfer amount, and therefore it is difficult to directly obtain a data conversion model between the steering characteristics and the load transfer amount. Therefore, the present invention conducts multiple experiments in advance to obtain the load transfer amount W of different values ​​of current steering characteristics corresponding to different values ​​of target steering characteristics, establishes a corresponding relationship model similar to a MAP diagram, stores it in the vehicle controller, obtains the current steering characteristics and the target steering characteristics, and obtains the load transfer amount W by looking up the table.

[0085] S3, calculating the target stiffness of the anti-roll bar according to the corresponding relationship between the load transfer amount and the stiffness of the anti-roll bar;

[0086] In fact, there is a lateral load transfer when the vehicle turns, and the transfer amount is composed of the following four parts:

[0087] (1) Elastic load transfer: borne by the elastic elements and anti-roll bars on both sides of the coaxial axis.

[0088] (2) Unsprung mass load transfer: wheels, tires, pillar systems, etc.

[0089] (3) Geometric load transfer: The lateral force acting on the center of mass of the sprung mass is equivalent to the additional torque at the roll center. This lateral force acting on the roll center causes a geometric load transfer, which is completed quickly and is borne by the suspension system.

[0090] (4) Additional load transfer caused by the center of mass of the unsprung mass deviating from the vehicle's x-axis.

[0091] The load transfer relationship of these four parts can be expressed by the following formula:

[0092]

[0093] Where, ΔW a Indicates the calculated axle load transfer (N), which is determined by the load transfer W and the calculated axis, where the anti-roll bar is located. represents the front axle roll stiffness (Nm / rad), Represents the rear axle roll stiffness (Nm / rad), W s represents the sprung mass (N), t represents the calculated axle track (m), L represents the wheelbase (m), A y represents lateral acceleration / gravitational acceleration, dimensionless, h s The distance from the center of mass of the sprung mass to the roll center (m), Z RC represents the roll center height (m), x represents the distance from the calculation axis to the center of mass (m), W ua is the unsprung mass (N), Z ua is the height of the center of mass of the unsprung mass (m), Indicates the calculated axle roll stiffness (Nm / rad).

[0094] As in this embodiment, reference Figure 3 , the anti-roll bar is installed on the rear axle, and the calculation axis is the rear axle, so the rear axle roll stiffness Calculate the axle roll stiffness is the same parameter. In the above formula, the other parameters are all known values, so the required roll stiffness can be inversely calculated in the above formula. The roll stiffness of the vehicle corresponds to the stiffness of the electronically controlled anti-roll bar. In this embodiment, the roll stiffness is the sum of the stiffness of the anti-roll bar and the stiffness of the suspension spring, and the electronically controlled lateral stiffness that needs to be responded can be obtained. In this way, the adjustment of the vehicle's roll characteristics and steering characteristics is achieved.

[0095] S4. Adjust the stiffness of the anti-roll bar based on the target stiffness so that the transferred load is the load transfer amount W obtained in the above step S2. Specifically, the target stiffness of the anti-roll bar is adjusted using closed-loop feedback, specifically:

[0096] 1) Adjust the stiffness of the anti-roll bar to the target stiffness;

[0097] 2) Obtain the real-time wheel load data of the vehicle and calculate the actual load transfer;

[0098] It should be noted that, since the real-time loads of the front and rear axles can be obtained by dynamic wheel load measurement, the load changes of the front and rear axles can be obtained by comparing the loads before and after the anti-roll bar adjustment, and the actual load transfer amount can be obtained. The load transfer amount W in step S2 is the expected load transfer amount determined according to the deviation between the current steering characteristic and the target steering characteristic, and the calculation methods of the two are different.

[0099] 3) According to the difference between the actual load transfer amount and the expected load transfer amount W, the target stiffness of the anti-roll bar is calculated through the corresponding relationship between the load transfer amount and the stiffness of the anti-roll bar;

[0100] 4) Repeat step 1) until the termination condition is met, where the termination condition is: the difference between the actual load transfer amount and the expected load transfer amount W is less than a preset deviation threshold, or the execution time of step S4 exceeds a preset time threshold.

[0101] The closed-loop feedback process is as follows: Figure 4 As shown, the input can be the load transfer amount or the target load transfer distribution ratio. The load transfer distribution ratio is equal to the ratio of the load transfer amount to the total load. In actual use, the load transfer amount is different for different vehicles and is difficult to unify. However, the load transfer distribution ratio can well unify the calculation of all vehicles and speed up the calculation. The present invention adopts closed-loop control with real-time feedback, which plays a great role in maintaining the stability of the vehicle under more intense working conditions.

[0102] The present invention also provides a vehicle steering characteristic adjustment system, comprising:

[0103] Wheel load determination module, used to obtain vehicle wheel load data;

[0104] A steering characteristic calculation module, used to calculate the current steering characteristic of the vehicle using wheel load data;

[0105] A load transfer amount calculation module is used to obtain the target steering characteristic of the vehicle, compare the current steering characteristic with the target steering characteristic, and obtain the load transfer amount W;

[0106] A stiffness calculation module, used for calculating the target stiffness of the anti-roll bar according to the corresponding relationship between the load transfer amount and the stiffness of the anti-roll bar;

[0107] The adjustment module is used to adjust the stiffness of the anti-roll bar based on the target stiffness so that the transferred load amount is the load transfer amount W obtained above.

[0108] Currently, the system is implemented on a small FSAE formula racing car, which includes a dynamic wheel load measurement system that can dynamically measure the wheel load of the vehicle while driving, an electronic lateral stability control device that can actively adjust the suspension roll stiffness, and a complete set of on-board electronic control system-related devices and related mechanical components.

[0109] Among them, the wheel load measurement module is installed in the vehicle chassis and electronic control system. The main measurement objects are the vehicle's suspension rods and damping shock absorbers. The suspension design parameters, motion parameters and dynamic parameters are used to solve the wheel load in real time, and related electronic components are used for data processing and transmission. The "A Vehicle Dynamic Wheel Load Measurement and Driving Safety Assistance System" disclosed in Chinese patent application CN2022103883415 can be used as the wheel load measurement module, or any other device and system that can measure the dynamic wheel load of the vehicle can be used.

[0110] The adjustment module is connected to an electronically controlled lateral stability control device, i.e., an electronically controlled anti-roll bar. The electronically controlled lateral stability control device is a device that can suppress the roll of the vehicle by changing the torsional stiffness of the anti-roll bar. It is connected to the suspension of the vehicle and can effectively adjust the roll characteristics of the entire vehicle, thereby effectively adjusting the steering characteristics of the vehicle. The existing electronically controlled anti-roll bar structure can be used, and its principle is not repeated here. The electronically controlled anti-roll bar in this embodiment is a blade-shaped torsion arm structure. By changing the torsion arm angle, the moment of inertia of different cross sections to the centroid axis is controlled, thereby changing the stiffness of the anti-roll bar.

[0111] The above-mentioned steering characteristic calculation module, load transfer calculation module, stiffness calculation module and adjustment module can all be programmed and implemented using the existing electronic control unit and related devices of the whole vehicle, and can effectively filter, transmit, process, store and communicate the data of the dynamic wheel load measurement system, as well as read the real-time data of the electronically controlled anti-roll bar and perform adjustments of the electronic components and controllers; and can install the dynamic wheel load measurement system and the mechanical bracket of the electronically controlled anti-roll bar and related fixing devices.

[0112] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the described module can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0113] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for adjusting vehicle steering characteristics, characterized in that: The following steps are involved: S1. Obtaining wheel load data of the vehicle, and using the wheel load data to calculate the current steering characteristics of the vehicle; S2. Obtain the target steering characteristic of the vehicle, compare the current steering characteristic with the target steering characteristic, and obtain the required load transfer amount W; S3, calculating the target stiffness of the anti-roll bar according to the corresponding relationship between the load transfer amount and the stiffness of the anti-roll bar; S4, adjusting the stiffness of the anti-roll bar based on the target stiffness so that the transferred load amount is the load transfer amount W obtained in the above step S2; The vehicle wheel load data includes the front axle load and the rear axle load, and the calculation formula of the current steering characteristic is: ， in, is the front axle load, is the rear axle load, is the cornering stiffness of the front wheel, is the cornering stiffness of the rear wheel; Compare the current steering characteristics with the target steering characteristics to obtain the load transfer amount W, which is: Conduct multiple tests in advance to obtain load transfer amounts W of different values ​​of current steering characteristics corresponding to different values ​​of target steering characteristics, store them in the vehicle controller, obtain the current steering characteristics and the target steering characteristics, and obtain the load transfer amount W by looking up the table; The corresponding relationship between load transfer and anti-roll bar stiffness is: ， in, represents the calculated axle load transfer, which is determined based on the load transfer W and the calculated axis, where the calculated axis is the axis where the anti-roll bar is located. represents the front axle roll stiffness, represents the rear axle roll stiffness, represents the sprung mass, t represents the calculated axle track, Indicates the wheelbase, represents the lateral acceleration / acceleration due to gravity, It represents the distance from the center of mass of the sprung mass to the roll center. represents the roll center height, x represents the distance from the calculation axis to the center of mass, is the unsprung mass, is the height of the center of mass of the unsprung mass, represents the calculated axle roll stiffness, the calculated axle lateral stiffness There is a corresponding relationship with the stiffness of the anti-roll bar; In step S4, the target stiffness of the anti-roll bar is adjusted using closed-loop feedback, specifically: 1) Adjust the stiffness of the anti-roll bar to the target stiffness; 2) Obtain the real-time wheel load data of the vehicle and calculate the actual load transfer; 3) According to the difference between the actual load transfer amount and the expected load transfer amount W, the target stiffness of the anti-roll bar is calculated through the corresponding relationship between the load transfer amount and the stiffness of the anti-roll bar; 4) Repeat 1) until the termination condition is met.

2. A vehicle steering characteristic adjustment method according to claim 1, characterized in that: The termination condition is: the difference between the actual load transfer amount and the expected load transfer amount W is less than a preset deviation threshold, or the execution time of step S4 exceeds a preset time threshold.

3. A vehicle steering characteristic adjustment system, characterized in that: include: Wheel load determination module, used to obtain vehicle wheel load data; A steering characteristic calculation module, used to calculate the current steering characteristic of the vehicle using the wheel load data; A load transfer amount calculation module is used to obtain the target steering characteristic of the vehicle, compare the current steering characteristic with the target steering characteristic, and obtain the load transfer amount W; A stiffness calculation module, used for calculating the target stiffness of the anti-roll bar according to the corresponding relationship between the load transfer amount and the stiffness of the anti-roll bar; An adjustment module, used for adjusting the stiffness of the anti-roll bar based on the target stiffness so that the transferred load amount is the load transfer amount W obtained above; The vehicle wheel load data includes the front axle load and the rear axle load, and the calculation formula of the current steering characteristic is: ,in, is the front axle load, is the rear axle load, is the cornering stiffness of the front wheel, is the cornering stiffness of the rear wheel; The corresponding relationship between load transfer and anti-roll bar stiffness is: ， in, represents the calculated axle load transfer, which is determined based on the load transfer W and the calculated axis, where the calculated axis is the axis where the anti-roll bar is located. represents the front axle roll stiffness, represents the rear axle roll stiffness, represents the sprung mass, t represents the calculated axle track, Indicates the wheelbase, represents the lateral acceleration / acceleration due to gravity, It represents the distance from the center of mass of the sprung mass to the roll center. represents the roll center height, x represents the distance from the calculation axis to the center of mass, is the unsprung mass, represents the height of the center of mass of the unsprung mass, and the calculated axle lateral stiffness There is a corresponding relationship with the stiffness of the anti-roll bar; The regulation module uses closed-loop feedback to adjust the target stiffness of the anti-roll bar, specifically: 1) Adjust the stiffness of the anti-roll bar to the target stiffness; 2) Obtain the real-time wheel load data of the vehicle and calculate the actual load transfer; 3) According to the difference between the actual load transfer amount and the expected load transfer amount W, the target stiffness of the anti-roll bar is calculated through the corresponding relationship between the load transfer amount and the stiffness of the anti-roll bar; 4) Repeat 1) until the termination condition is met.

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