A distributed drive vehicle overspeed instability alarm control method and system

Abstract

The invention discloses a distributed drive vehicle overspeed instability alarm control method and system. The method comprises measuring the longitudinal and lateral accelerations of the vehicle through an acceleration sensor, measuring the vehicle speed through a vehicle speed sensor, and measuring the rotation speeds of four wheels through a wheel speed sensor, estimating the road adhesion coefficient through an adhesion coefficient estimation unit, calculating the vehicle vertical force according to the vehicle structural parameters, the acceleration sensor, and the data obtained by the wheel speed sensor, calculating the maximum grip of the tire according to the vehicle vertical force and the adhesion coefficient of the road estimated by the adhesion coefficient estimation unit, calculating the tire side slip angle of the vehicle according to the tire steering wheel angle and the lateral and longitudinal speeds of the vehicle, and calculating the slip rate of the vehicle according to the wheel speed sensor and the vehicle speed sensor. The invention prevents the occurrence of vehicle instability and improves the safety of vehicle driving.

Description

Technical Field

[0001] The present invention relates to the technical field of active safety control of new energy vehicles, and in particular to a distributed drive vehicle overspeed instability alarm control method and system. Background Art

[0002] As the number of cars increases, road traffic accidents also increase, and the field of automobile safety has gradually become an important direction of the automobile industry. The frequent occurrence of safety accidents has led people to invest a lot of research in seat belts, airbags, car black boxes, safety glass, etc., but to fundamentally improve vehicle safety performance, the automobile industry needs to focus more on active safety technology. Tire force is the driving force that makes the car move forward, and it is also the focus of the automobile safety field. In the case of insufficient tire force, the vehicle should maintain an appropriate speed to prevent the vehicle from becoming unstable. Summary of the invention

[0003] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0004] Therefore, the purpose of the present invention is to provide a distributed drive vehicle overspeed instability alarm control method to prevent the vehicle from becoming unstable and improve the safety of vehicle driving.

[0005] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0006] A distributed drive vehicle overspeed instability alarm control method, comprising:

[0007] S1, measuring the longitudinal and lateral accelerations of the vehicle by an acceleration sensor, measuring the vehicle speed by a vehicle speed sensor, and measuring the rotation speeds of four wheels by a wheel speed sensor, and estimating the road adhesion coefficient by an adhesion coefficient estimation unit;

[0008] S2, calculating the vertical force of the vehicle according to the vehicle structural parameters, the acceleration sensor and the data obtained by the wheel speed sensor;

[0009] S3, calculating the maximum grip of the tire according to the vertical force of the vehicle and the adhesion coefficient of the road surface estimated by the adhesion coefficient estimation unit;

[0010] S4, calculating the tire slip angle of the vehicle according to the tire steering wheel angle and the lateral and longitudinal speeds of the vehicle, and calculating the slip rate of the vehicle according to the wheel speed sensor and the vehicle speed sensor;

[0011] S5. Calculate the lateral force of the tire using the HSRI tire model according to the slip rate of the vehicle wheel and the sideslip angle of the vehicle tire;

[0012] S6. Calculate the maximum longitudinal force that the vehicle can achieve on the current road surface based on the lateral force and the ground grip;

[0013] S7, calculating the maximum longitudinal speed that the vehicle can achieve on the current road surface according to the maximum longitudinal force that the vehicle can achieve on the current road surface;

[0014] S8. Calculate the vehicle warning speed and braking speed according to the maximum longitudinal speed that the vehicle can reach on the current road surface, compare the actual vehicle speed with the vehicle warning speed and braking speed, determine the state of the instability alarm system, and send a control command.

[0015] As a preferred solution of the distributed drive vehicle overspeed instability alarm control method of the present invention, in step S2, the calculation of the vehicle vertical force is as follows:

[0016]

[0017]

[0018]

[0019]

[0020] Among them, F z，ij is the wheel vertical force, ij=ff, fl, rl, rr correspond to the left front wheel, right front wheel, left rear wheel, right rear wheel respectively, a x is the longitudinal acceleration measurement value, a y is the lateral acceleration measurement value, l is the vehicle wheelbase, h is the height from the vehicle center of mass to the ground, a is the distance from the vehicle center of mass to the front axle, b is the distance from the vehicle center of mass to the rear axle, l f is the front wheel track of the vehicle, l r The rear wheel track of the vehicle.

[0021] As a preferred solution of the distributed drive vehicle overspeed instability alarm control method of the present invention, in step S3, the tire grip is calculated as follows:

[0022] F XY，ij =μF z，ij

[0023] Among them, μ is the road friction factor.

[0024] As a preferred solution of the distributed drive vehicle overspeed instability alarm control method of the present invention, in step S4, the tire side slip angle is calculated as follows:

[0025]

[0026]

[0027]

[0028]

[0029] The slip ratio is calculated as follows:

[0030]

[0031] γ y，ij =tanα ij

[0032] Among them, γ x，ij is the wheel longitudinal slip rate, γ y，ij is the wheel lateral slip rate, ω ij are the four wheel angular velocities obtained by the wheel speed sensor, r w is the wheel radius.

[0033] As a preferred solution of the distributed drive vehicle overspeed instability alarm control method of the present invention, in step S5, the lateral force of the tire is calculated as follows:

[0034]

[0035] in,

[0036]

[0037] In the formula, F y，ij is the wheel lateral force, C s is the tire longitudinal slip stiffness, C a is the tire cornering stiffness.

[0038] As a preferred solution of the distributed drive vehicle overspeed instability alarm control method of the present invention, in step S6, the maximum longitudinal force that can be achieved by the road surface is calculated as follows:

[0039]

[0040] Among them, P is the longitudinal force adjustment factor.

[0041] As a preferred solution of the distributed drive vehicle overspeed instability alarm control method of the present invention, in step S7, the maximum longitudinal speed of the vehicle is calculated as follows:

[0042] F T =F xm，fl +Fxm，rl +F xm，rl +F xm，rr

[0043]

[0044] Among them, C D is the air resistance coefficient, A is the windward area, V xm is the maximum longitudinal speed that the car can reach.

[0045] As a preferred solution of the distributed drive vehicle overspeed instability alarm control method of the present invention, in step S8, the vehicle alarm speed is: V alert =0.80V xm , the car brake speed is: V brake =0.90V xm ;

[0046] When the car speed is less than the car alarm speed, the central processing module issues a decision result and does not issue a command to the alarm control system and the brake control system. When the car speed is between the car alarm speed and the brake speed, the central processing module issues a decision result and does not issue a command to the brake system, but issues a command to the alarm control system to warn the car of overspeed. When the car speed is greater than the brake speed, the central processing module issues a decision result and issues a command to the brake system and the alarm system at the same time. The car brakes to below the alarm speed and issues a car overspeed alarm.

[0047] A distributed drive vehicle overspeed instability alarm system, comprising:

[0048] The data acquisition module includes a vehicle speed sensor, an acceleration sensor, a wheel speed sensor, a steering wheel angle sensor, an adhesion coefficient estimation unit and a vehicle parameter unit, wherein the vehicle parameter unit stores fixed parameter information of the vehicle structure;

[0049] The central processing module receives the signals output by the vehicle speed sensor, the acceleration sensor, the wheel speed sensor, the steering wheel angle sensor, the adhesion coefficient estimation unit and the vehicle parameter unit, calculates the longitudinal force, vertical force, lateral force and tire force margin of the vehicle, and calculates the vehicle speed that the vehicle can reach under the tire margin according to the tire margin, makes a judgment according to the speed of the vehicle, and respectively gives an alarm to the driver or brakes the vehicle;

[0050] The execution module is used to send control instructions to the alarm control system and the brake control system according to the decision results calculated by the central processing module.

[0051] Compared with the prior art, the present invention has the following beneficial effects: when the speed of the vehicle is less than the alarm speed of the vehicle, the central processing module issues a decision result and does not issue a command to the alarm control system and the brake control system. When the speed of the vehicle is between the alarm speed of the vehicle and the brake speed, the central processing module issues a decision result and does not issue a command to the brake system, but issues a command to the alarm control system to warn that the vehicle is overspeeding. When the speed of the vehicle is greater than the brake speed, the central processing module issues a decision result and issues a command to the brake system and the alarm system at the same time, the vehicle brakes to a speed below the alarm speed, and issues a vehicle overspeed alarm, thereby improving the safety of vehicle driving. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below in combination with the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0053] Figure 1 The present invention is a flow chart of a distributed drive vehicle overspeed instability alarm control method. DETAILED DESCRIPTION

[0054] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0055] Secondly, the present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0056] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0057] The invention provides a distributed drive automobile overspeed instability alarm control method, which prevents automobile instability from occurring and improves automobile driving safety.

[0058] See also Figure 1 , a distributed drive vehicle overspeed instability alarm control method, comprising:

[0059] S1, measuring the longitudinal and lateral accelerations of the vehicle by an acceleration sensor, measuring the vehicle speed by a vehicle speed sensor, and measuring the rotation speeds of four wheels by a wheel speed sensor, and estimating the road adhesion coefficient by an adhesion coefficient estimation unit;

[0060] S2. Calculate the vertical force of the vehicle based on the vehicle structural parameters, the acceleration sensor, and the data obtained by the wheel speed sensor. Specifically, the vertical force of the vehicle is calculated as follows:

[0061]

[0062]

[0063]

[0064]

[0065] Among them, F z，ij is the wheel vertical force, ij=ff, fl, rl, rr correspond to the left front wheel, right front wheel, left rear wheel, right rear wheel respectively, a x is the longitudinal acceleration measurement value, a y is the lateral acceleration measurement value, l is the vehicle wheelbase, h is the height from the vehicle center of mass to the ground, a is the distance from the vehicle center of mass to the front axle, b is the distance from the vehicle center of mass to the rear axle, l f is the front wheel track of the vehicle, l r The rear wheel track of the vehicle.

[0066] S3. Calculate the maximum tire grip according to the vertical force of the vehicle and the adhesion coefficient of the road surface estimated by the adhesion coefficient estimation unit. Specifically, the tire grip is calculated as follows:

[0067] F xY，ij =μF z，ij

[0068] Among them, μ is the road friction factor;

[0069] S4. Calculate the tire slip angle of the vehicle according to the tire steering wheel angle and the lateral and longitudinal speeds of the vehicle, and calculate the slip rate of the vehicle according to the wheel speed sensor and the vehicle speed sensor. Specifically, the tire slip angle is calculated as follows:

[0070]

[0071]

[0072]

[0073]

[0074] The slip ratio is calculated as follows:

[0075]

[0076] γ y，ij=tanα ij

[0077] Among them, γ x，ij is the wheel longitudinal slip rate, γ y，ij is the wheel lateral slip rate, ω ij are the four wheel angular velocities obtained by the wheel speed sensor, r w is the wheel radius.

[0078] S5. According to the slip rate of the vehicle wheel and the sideslip angle of the vehicle tire, the lateral force of the tire is calculated using the HSRI tire model. Specifically, the lateral force of the tire is calculated as follows:

[0079]

[0080] in,

[0081]

[0082] In the formula, F y，ij is the wheel lateral force, C s is the tire longitudinal slip stiffness, C a is the tire cornering stiffness;

[0083] S6. Calculate the maximum longitudinal force that the vehicle can achieve on the current road surface based on the lateral force and the ground grip. Specifically, the maximum longitudinal force that the road surface can achieve is calculated as follows:

[0084]

[0085] Among them, P is the longitudinal force adjustment factor.

[0086] S7. Calculate the maximum longitudinal speed that the vehicle can reach on the current road surface based on the maximum longitudinal force that the vehicle can reach on the current road surface. Specifically, the maximum longitudinal speed of the vehicle is calculated as follows:

[0087] F T =F xm，fl +F xm，rl +F xm，rl +F xm，rr

[0088]

[0089] Among them, C D is the air resistance coefficient, A is the windward area, V xm is the maximum longitudinal speed that the car can reach;

[0090] S8. Calculate the car alarm speed and braking speed according to the maximum longitudinal speed that the car can reach on the current road surface, compare the actual car speed with the car alarm speed and braking speed, determine the state of the instability alarm system, and send a control command. Specifically, the car alarm speed is: V alert =0.80V xm , the car brake speed is: V brake =0.90V xm ;

[0091] When the car speed is less than the car alarm speed, the central processing module issues a decision result and does not issue a command to the alarm control system and the brake control system. When the car speed is between the car alarm speed and the brake speed, the central processing module issues a decision result and does not issue a command to the brake system, but issues a command to the alarm control system to warn the car of overspeed. When the car speed is greater than the brake speed, the central processing module issues a decision result and issues a command to the brake system and the alarm system at the same time. The car brakes to below the alarm speed and issues a car overspeed alarm.

[0092] In order to implement the above method steps, the present invention also provides a distributed drive vehicle overspeed instability alarm system, which includes:

[0093] The data acquisition module includes a vehicle speed sensor, an acceleration sensor, a wheel speed sensor, a steering wheel angle sensor, an adhesion coefficient estimation unit and a vehicle parameter unit, wherein the vehicle parameter unit stores fixed parameter information of the vehicle structure;

[0094] The central processing module receives the signals output by the vehicle speed sensor, the acceleration sensor, the wheel speed sensor, the steering wheel angle sensor, the adhesion coefficient estimation unit and the vehicle parameter unit, calculates the longitudinal force, vertical force, lateral force and tire force margin of the vehicle, and calculates the vehicle speed that the vehicle can reach under the tire margin according to the tire margin, makes a judgment according to the speed of the vehicle, and respectively gives an alarm to the driver or brakes the vehicle;

[0095] The execution module is used to send control instructions to the alarm control system and the brake control system according to the decision results calculated by the central processing module.

[0096] Although the present invention has been described above with reference to the embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed in the present invention may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A distributed drive vehicle overspeed instability alarm control method, characterized in that: include: S1, measuring the longitudinal and lateral accelerations of the vehicle by an acceleration sensor, measuring the vehicle speed by a vehicle speed sensor, and measuring the rotation speeds of four wheels by a wheel speed sensor, and estimating the road adhesion coefficient by an adhesion coefficient estimation unit; S2, calculating the vertical force of the vehicle according to the vehicle structural parameters, the acceleration sensor and the data obtained by the wheel speed sensor; S3, calculating the maximum grip of the tire according to the vertical force of the vehicle and the adhesion coefficient of the road surface estimated by the adhesion coefficient estimation unit; S4, calculating the tire slip angle of the vehicle according to the tire steering wheel angle and the lateral and longitudinal speeds of the vehicle, and calculating the slip rate of the vehicle according to the wheel speed sensor and the vehicle speed sensor; S5. Calculate the lateral force of the tire using the HSRI tire model according to the slip rate of the vehicle wheel and the sideslip angle of the vehicle tire; S6. Calculate the maximum longitudinal force that the vehicle can achieve on the current road surface based on the lateral force and the ground grip; S7, calculating the maximum longitudinal speed that the vehicle can achieve on the current road surface according to the maximum longitudinal force that the vehicle can achieve on the current road surface; S8. Calculate the warning speed and braking speed of the vehicle according to the maximum longitudinal speed that the vehicle can reach on the current road surface, compare the actual vehicle speed with the warning speed and braking speed of the vehicle, determine the state of the instability warning system, and send a control command.

2. A distributed drive vehicle overspeed instability alarm control method according to claim 1, characterized in that: In step S2, the vertical force of the vehicle is calculated as follows: Among them, F z,ij is the wheel vertical force, ij=ff, fl, rl, rr correspond to the left front wheel, right front wheel, left rear wheel, right rear wheel respectively, a x is the longitudinal acceleration measurement value, a y is the lateral acceleration measurement value, l is the vehicle wheelbase, h is the height from the vehicle center of mass to the ground, a is the distance from the vehicle center of mass to the front axle, b is the distance from the vehicle center of mass to the rear axle, l f is the front wheel track of the vehicle, l r The rear wheel track of the vehicle.

3. A distributed drive vehicle overspeed instability alarm control method according to claim 2, characterized in that: In step S3, the tire grip is calculated as follows: F XY,ij =μ Fz,ij Among them, μ is the road friction factor.

4. A distributed drive vehicle overspeed instability alarm control method according to claim 3, characterized in that: In step S4, the tire slip angle is calculated as follows: The slip ratio is calculated as follows: c y，ij =tan ij Among them, γ x，ij is the wheel longitudinal slip rate, γ y，ij is the wheel lateral slip rate, ω ij are the four wheel angular velocities obtained by the wheel speed sensor, r w is the wheel radius.

5. A distributed drive vehicle overspeed instability alarm control method according to claim 4, characterized in that: In step S5, the lateral force of the tire is calculated as follows: in, In the formula, F y,ij is the wheel lateral force, C s is the tire longitudinal slip stiffness, C a is the tire cornering stiffness.

6. A distributed drive vehicle overspeed instability alarm control method according to claim 5, characterized in that: In step S6, the maximum longitudinal force that can be achieved by the road surface is calculated as follows: Among them, P is the longitudinal force adjustment factor.

7. A distributed drive vehicle overspeed instability alarm control method according to claim 6, characterized in that: In step S7, the maximum longitudinal speed of the vehicle is calculated as follows: F T =F xm，fl +F xm，rl +F xm，rl +F xm，rr Among them, C D is the air resistance coefficient, A is the windward area, C xm is the maximum longitudinal speed that the car can reach.

8. A distributed drive vehicle overspeed instability alarm control method according to claim 7, characterized in that: In step S8, the vehicle alarm speed is: V alert =0.80V xm , the car brake speed is: V brake =0.90V xm ; When the car speed is lower than the car alarm speed, the central processing module issues a decision result and does not send commands to the alarm control system and the braking control system. When the car speed is between the car alarm speed and the braking speed, the central processing module issues a decision result and does not send commands to the braking system, but sends commands to the alarm control system to warn the car of speeding. When the car speed is higher than the braking speed, the central processing module issues a decision result and sends commands to the braking system and the alarm system at the same time. The car speed is braked to below the alarm speed and a car overspeed alarm is issued.

9. A distributed drive vehicle overspeed instability alarm system, implementing the steps of a distributed drive vehicle overspeed instability alarm control method as claimed in any one of claims 1 to 8, characterized in that: include: The data acquisition module includes a vehicle speed sensor, an acceleration sensor, a wheel speed sensor, a steering wheel angle sensor, an adhesion coefficient estimation unit, and a vehicle parameter unit, wherein the vehicle parameter unit stores fixed parameter information of the vehicle structure; The central processing module receives the signals output by the vehicle speed sensor, the acceleration sensor, the wheel speed sensor, the steering wheel angle sensor, the adhesion coefficient estimation unit and the vehicle parameter unit, calculates the longitudinal force, vertical force, lateral force and tire margin of the vehicle, and calculates the vehicle speed that the vehicle can reach under the tire margin according to the tire margin, makes a judgment according to the speed of the vehicle, and respectively issues an alarm to the driver or brakes the vehicle; The execution module is used to send control instructions to the alarm control system and the brake control system according to the decision results calculated by the central processing module.

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