CN206781743U - Automobile differential steering system with a variety of collision avoidance patterns - Google Patents

Abstract

The utility model discloses an automobile differential steering system with multiple collision avoidance modes, comprising a radar, a vehicle speed sensor, a yaw angular velocity sensor, a lateral acceleration sensor, a front wheel angle sensor, a signal integration module, a judging module, and a steering module , braking module and ECU. When the car is running, the radar detects the speed of the vehicle in front and the relative distance between the vehicle and the vehicle in front, and the ECU controls the steering module and braking module of the car according to the relationship between the measured relative distance and the steering safety distance and braking safety distance. ; At the same time, using the yaw rate and the side slip angle of the center of mass as the control parameters, the stability of the car is regulated by the sliding film control. The utility model can provide active collision avoidance in the horizontal and vertical directions of the automobile, assist the driver to control the vehicle in an emergency, and improve the safety and stability of the automobile driving.

Description

Automotive Differential Steering System with Multiple Collision Avoidance Modes

technical field

The utility model relates to the field of automobile auxiliary driving, in particular to an automobile differential steering system with multiple collision avoidance modes.

Background technique

As the active safety of automobiles has attracted more and more attention from the public, the assisted driving technology of automobiles has gradually entered people's sight. At present, assisted driving technologies include lane keeping, automatic parking, anti-slip acceleration, etc., which to a certain extent assist the driver in manipulating the vehicle and provide certain safety guarantees for driving. But these assistive technologies all have one thing in common-only consider the longitudinal safety of the car.

However, in the actual driving process, it is not enough to only rely on braking to achieve active collision avoidance. The basic principle of collision avoidance in pure braking mode is to increase the distance between vehicles and reduce the speed of vehicles. However, reducing the speed and increasing the distance between vehicles will reduce the road capacity and reduce the efficiency of road traffic, which does not meet the current requirements of intelligent transportation; On the other hand, when the braking deceleration is too large, it will cause discomfort to passengers. It can be seen that although collision avoidance in this single mode can reduce accidents or reduce the degree of injury of accidents, there are also disadvantages.

In addition, the car adopts different modes to avoid collisions, and everything must be based on ensuring the driving safety and handling stability of the car. Therefore, in order to prevent the occurrence of various dangerous situations, a stable and reliable controller is also essential.

Utility model content

The technical problem to be solved by the utility model is to provide an automobile differential steering system with multiple collision avoidance modes aiming at the defects involved in the background technology.

The utility model adopts the following technical solutions for solving the above-mentioned technical problems:

A vehicle differential steering system with multiple collision avoidance modes, including radar, vehicle speed sensor, yaw rate sensor, lateral acceleration sensor, front wheel angle sensor, signal integration module, judgment module, steering module, braking module and ECU;

The radar is arranged at the front of the vehicle, and is used to obtain the distance between the vehicle in front and the vehicle, the speed of the vehicle in front, and transmit it to the signal integration module;

The vehicle speed sensor, the yaw rate sensor, the lateral acceleration sensor, and the front wheel angle sensor are respectively used to collect the vehicle speed of the automobile, the yaw rate of the automobile, the lateral acceleration of the automobile, and the front wheel angle of the automobile, and transmit it to The signal integration module;

The signal integration module is respectively connected with the radar, vehicle speed sensor, yaw rate sensor, lateral acceleration sensor, front wheel angle sensor, judgment module, and ECU, and is used to integrate the received data into a working condition signal and input it to the ECU. And according to the speed of the vehicle in front received, the speed of the vehicle, the yaw rate of the vehicle, the lateral acceleration of the vehicle, and the front wheel angle of the vehicle, the steering safety distance and the braking safety distance of the vehicle are calculated, and the distance between the vehicle in front and the vehicle is calculated. The distance between them, the steering safety distance under the current working condition and the braking safety distance are passed to the judgment module;

The judging module is used to compare the distance between the vehicle in front and the car with the braking safety distance and the steering safety distance respectively, and input the comparison results into the ECU;

The steering module includes a hub motor for controlling the steering of the vehicle;

The brake module includes ABS, which is used to control the car to brake;

The ECU is also connected to the steering module and the braking module respectively, and is used to control the steering module and the braking module to work according to the comparison result input by the judging module.

The utility model can be controlled by using the existing general collision avoidance control method including steering and braking. Here, a control method based on the automobile differential steering system with multiple collision avoidance modes is provided. Include the following steps:

Step 1), obtain the speed of the vehicle in front, the distance between the vehicle in front and the car through the radar;

Step 2), obtain the vehicle speed of automobile, yaw rate, lateral acceleration, front wheel angle respectively by vehicle speed sensor, yaw rate sensor, lateral acceleration sensor, front wheel angle sensor;

Step 3), according to the vehicle speed of the vehicle in front, the vehicle speed of the vehicle in front and the relative distance between the two vehicles, the steering safety distance and the braking safety distance of the vehicle under this working condition are solved;

Step 4), the judging module compares the steering safety distance and the braking safety distance with the relative distance of the two vehicles, and transmits the comparison result to the ECU;

Step 5), the ECU controls the steering module and the braking module to avoid obstacles according to the comparison result of the judging module, and at the same time controls the vehicle's driving stability based on the sliding film control.

As a further optimization scheme of the control method of a vehicle differential steering system with multiple collision avoidance modes of the present invention, in the step 3), the steering safety distance D _s and the braking safety distance D _b are calculated according to the following formula;

In the formula, t ₁ is the braking time, a is the deceleration, take μg, μ is the preset ground adhesion coefficient, g is the acceleration of gravity; t ₂ is the preset lane change time threshold; v ₀ is the speed of the car; v is the speed of the vehicle in front; v ₁ is The speed at which the car begins to change lanes.

As a further optimization scheme of the control method of the vehicle differential steering system with multiple collision avoidance modes of the present invention, the preset lane change time threshold _t2 is 4.2s.

As a further optimization scheme of the control method of a kind of automobile differential steering system with multiple collision avoidance modes of the present invention, in the step 5), the ECU controls the detailed steps of the work of the steering module and the braking module according to the comparison result of the judging module as follows;

When the distance between the vehicle in front and the car is S≥D _s , the ECU controls the steering module to work to achieve obstacle avoidance in the steering mode, and the braking module does not work;

When D _b < S < D _s , the ECU first controls the steering module and the braking module to work at the same time, and realizes obstacle avoidance in the mode of braking first and then steering;

When S≤D _b , the ECU controls the braking module to work, and realizes obstacle avoidance in emergency braking mode, and the steering module does not work.

As a further optimization scheme of the control method of a kind of automobile differential steering system with multiple collision avoidance modes of the present invention, in step 5), the specific steps for the ECU to carry out the driving stability control of the automobile based on the synovial film control are as follows:

Step 5.1), the ECU adopts the method of joint control of yaw rate and sideslip angle, and calculates the expected value of the control parameters according to the working condition signal input by the signal integration module, where the expected side slip angle β _q ≤ 10deg, and the expected lateral slip angle The yaw rate γ _q is calculated by the following formula:

In the formula, θ _f is the front wheel angle of the car; L and K are the preset distance between the front and rear axles of the car and the preset car stability parameters, respectively;

Step 5.2), establish the differential power steering system model, and take the control system state variables Input variable u=[T _h ,F _δ ,i] ^T , output variable y=[T _a T _sen ] ^T , the corresponding state equation is:

In the formula,

θ _h is the input angle of the steering wheel of the car; T _h is the steering torque acting on the steering wheel of the car; J _h is the moment of inertia of the input shaft of the steering column; B _h is the viscous damping coefficient of the input shaft of the car; T _sen is the torque of the car The reaction torque on the rod; n ₁ is the transmission ratio from the steering gear to the front wheel; d is the lateral offset of the kingpin of the left and right steering wheels of the car; r _w is the rolling radius of the car wheel; x _r is the car rack r _p is the radius of the car pinion; M _r is the equivalent mass of the car rack and pinion steering gear; i is the difference between the control current of the left and right hub motors of the car; K _r is the equivalent of the output shaft of the car rack and pinion steering gear Spring stiffness; K _sen is the stiffness coefficient of the torsion bar connected to the input shaft in the car; K _a is the torque coefficient of the hub motor; B _r is the equivalent damping coefficient of the output shaft of the rack and pinion steering gear of the car; F _δ is the road surface random signal; T _a is the differential steering torque;

Step 5.3), establish the state-space model of synovium control as:

In the formula, f(x(t))=Ax(t); g(x(t))u(t)=Bu(t); h(x(t))=Cx(t); t is time;

Step 5.4), define the switching surface of yaw rate and sideslip angle

In the formula, E=XX _q is the real-time error of the yaw rate of the vehicle and the sideslip angle of the center of mass; λ is a preset normal number;

Step 5.5), define the input of the intermediate control quantity make K ₁ and K ₂ are sign functions and switching surfaces Between two linear combination coefficients; sgn is a sign function;

Step 5.5), determine the control law that satisfies the sliding mode surface as And based on this, the driving stability control of the car is carried out.

Compared with the prior art by adopting the above technical scheme, the utility model has the following technical effects:

1. Establish a new safety distance model, and divide the vehicle's active collision avoidance mode into three types, namely steering mode, braking first and then steering mode, and emergency braking mode.

2. The various collision avoidance modes provided by the utility model are suitable for various working conditions of automobiles, can more effectively reduce the accident rate, and can reduce accident injuries to the greatest extent.

3. The collision avoidance system disclosed in the utility model guarantees the safety of the automobile from the horizontal and vertical directions, improves the driving safety of the automobile on the one hand, and ensures the traffic efficiency on the other hand, meeting the requirements of intelligent transportation.

4. The sliding film variable structure controller designed by the utility model can provide a certain guarantee for the steering stability of the automobile.

Description of drawings

Fig. 1 is the selection structural representation of the multiple modes of automobile active collision avoidance system in the utility model;

Fig. 2 is a schematic flow chart of the sliding mode variable structure control method in the present invention.

detailed description

Below in conjunction with accompanying drawing, the technical scheme of the utility model is described in further detail:

As shown in Figure 1, the utility model discloses a vehicle differential steering system with multiple collision avoidance modes, including a radar, a vehicle speed sensor, a yaw rate sensor, a lateral acceleration sensor, a front wheel angle sensor, and a signal integration module , judging module, steering module, braking module and ECU;

The radar is arranged at the front of the vehicle, and is used to obtain the distance between the vehicle in front and the vehicle, the speed of the vehicle in front, and transmit it to the signal integration module;

The vehicle speed sensor, the yaw rate sensor, the lateral acceleration sensor, and the front wheel angle sensor are respectively used to collect the vehicle speed of the automobile, the yaw rate of the automobile, the lateral acceleration of the automobile, and the front wheel angle of the automobile, and transmit it to The signal integration module;

The signal integration module is respectively connected with the radar, vehicle speed sensor, yaw rate sensor, lateral acceleration sensor, front wheel angle sensor, judgment module, and ECU, and is used to integrate the received data into a working condition signal and input it to the ECU. And according to the speed of the vehicle in front received, the speed of the vehicle, the yaw rate of the vehicle, the lateral acceleration of the vehicle, and the front wheel angle of the vehicle, the steering safety distance and the braking safety distance of the vehicle are calculated, and the distance between the vehicle in front and the vehicle is calculated. The distance between them, the steering safety distance under the current working condition and the braking safety distance are passed to the judgment module;

The judging module is used to compare the distance between the vehicle in front and the car with the braking safety distance and the steering safety distance respectively, and input the comparison results into the ECU;

The steering module includes a hub motor for controlling the steering of the vehicle;

The brake module includes ABS, which is used to control the car to brake;

The ECU is also connected to the steering module and the braking module respectively, and is used to control the steering module and the braking module to work according to the comparison result input by the judging module.

The utility model can be controlled by using the existing general collision avoidance control method including steering and braking. Here, as shown in FIG. A control method for an automobile differential steering system, comprising the following steps:

Step 1), obtain the speed of the vehicle in front, the distance between the vehicle in front and the car through the radar;

Step 2), obtain the vehicle speed of automobile, yaw rate, lateral acceleration, front wheel angle respectively by vehicle speed sensor, yaw rate sensor, lateral acceleration sensor, front wheel angle sensor;

Step 3), according to the vehicle speed of the vehicle in front, the vehicle speed of the vehicle in front and the relative distance between the two vehicles, the steering safety distance and the braking safety distance of the vehicle under this working condition are solved;

Step 4), the judging module compares the steering safety distance and the braking safety distance with the relative distance of the two vehicles, and transmits the comparison result to the ECU;

Step 5), the ECU controls the steering module and the braking module to avoid obstacles according to the comparison result of the judging module, and at the same time controls the vehicle's driving stability based on the sliding film control.

In the step 3), the steering safety distance D _s and the braking safety distance D _b are calculated according to the following formula;

have to:

Among them: a is the deceleration, take μg, μ is the preset ground adhesion coefficient, g is the acceleration of gravity; _t1 is the braking time, t ₂ is the preset lane change time threshold; v ₀ is the speed of the car; v is the speed of the vehicle in front; v ₁ is the speed when the car starts to change lanes; s ₁ is the braking distance _; distance traveled.

The preset lane change time threshold _t2 is preferably 4.2s.

In described step 5), the detailed steps that ECU controls steering module, braking module work according to the comparison result of judging module are as follows;

When the distance between the vehicle in front and the car is S≥D _s , the ECU controls the steering module to work to achieve obstacle avoidance in the steering mode, and the braking module does not work;

When D _b < S < D _s , the ECU first controls the steering module and the braking module to work at the same time, and realizes obstacle avoidance in the mode of braking first and then steering;

When S≤D _b , the ECU controls the braking module to work, and realizes obstacle avoidance in emergency braking mode, and the steering module does not work.

In described step 5), the concrete steps that ECU carries out driving stability control to automobile based on synovial membrane control are as follows:

Step 5.1), the ECU adopts the joint control method of the yaw rate and the sideslip angle of the center of mass, and calculates the expected value of the control parameter according to the working condition signal input by the signal integration module, where the expected yaw rate γ _q is calculated by the following formula:

In the formula, θ _f is the front wheel angle of the car; L and K are the preset distance between the front and rear axles of the car and the preset car stability parameters, respectively;

Expected center of mass sideslip angle: In order to limit the side slip of the vehicle as much as possible, the expected sideslip angle β _q is usually taken as 0. But in reality, the center-of-mass side slip angle β cannot be maintained at 0. When the side slip angle β is greater than 10 degrees, the general driver will not be able to continue to control the movement of the vehicle. So: β _q ≤ 10deg.

Step 5.2), establish the differential power steering system model, and take the control system state variables Input variable u=[T _h ,F _δ ,i] ^T , output variable y=[T _a T _sen ] ^T , the corresponding state equation is:

In the formula,

θ _h is the input angle of the steering wheel of the car; T _h is the steering torque acting on the steering wheel of the car; J _h is the moment of inertia of the input shaft of the steering column; B _h is the viscous damping coefficient of the input shaft of the car; T _sen is the torque of the car The reaction torque on the rod; n ₁ is the transmission ratio from the steering gear to the front wheel; d is the lateral offset of the kingpin of the left and right steering wheels of the car; r _w is the rolling radius of the car wheel; x _r is the car rack r _p is the radius of the car pinion; M _r is the equivalent mass of the car rack and pinion steering gear; i is the difference between the control current of the left and right hub motors of the car; K _r is the equivalent of the output shaft of the car rack and pinion steering gear Spring stiffness; K _sen is the stiffness coefficient of the torsion bar connected to the input shaft in the car; K _a is the torque coefficient of the hub motor; B _r is the equivalent damping coefficient of the output shaft of the rack and pinion steering gear of the car; F _δ is the road surface Random signal; T _a is the differential steering torque.

Step 5.3), establish the state-space model of synovium control as:

In the formula, f(x(t))=Ax(t); g(x(t))u(t)=Bu(t); h(x(t))=Cx(t); t is time.

Step 5.4), define the switching surface of yaw rate and sideslip angle

In the formula, E is the error, E=XX _q , where it represents the real-time error of the yaw rate of the vehicle and the sideslip angle of the center of mass; λ is a preset normal constant.

Step 5.5), define the input of the intermediate control quantity Ensuring the accessibility of switching surfaces;

make K ₁ and K ₂ are sign functions and switching surfaces Between two linear combination coefficients; sgn is a sign function;

In addition, in order to eliminate the chattering phenomenon of the control output during the control process, the saturation function can be used to replace sgn(S), that is:

In the formula, δ>0, it is the boundary given for the introduction of the boundary layer, which can be arbitrarily small;

Step 5.5), determine the control law that satisfies the sliding mode surface as And based on this, the driving stability control of the car is carried out.

The sliding film control is based on the desired yaw angular velocity and the desired side slip angle of the center of mass as the control target, and the differential steering torque of the left and right wheels of the car and the reaction torque on the torsion bar of the car are adjusted by the hub motor to make the real-time yaw rate of the car And the side slip angle of the center of mass is close to the expected value, so as to obtain stable steering of the car.

During the driving process of the car, the ECU collects the steering wheel angle, yaw rate, center of mass side slip angle and vehicle speed signals in real time, and calculates the difference between the expected yaw rate and the actual yaw rate, the expected center of mass side slip angle and the side slip angle of the center of mass, The real-time yaw rate and sideslip angle of the center of mass of the vehicle are corrected by sliding mode control, so as to complete the stability control of the vehicle during lateral and longitudinal collision avoidance.

Those skilled in the art can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meanings as commonly understood by those of ordinary skill in the art to which the present invention belongs. It should also be understood that terms such as those defined in commonly used dictionaries should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted in an idealized or overly formal sense unless defined as herein Explanation.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present utility model in detail. For the utility model, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the utility model shall be included in the protection scope of the utility model.

Claims (1)

1. A kind of 1. automobile differential steering system with a variety of collision avoidance patterns, it is characterised in that including radar, vehicle speed sensor, Yaw-rate sensor, lateral acceleration sensor, front wheel angle sensor, signal integration module, judge module, steering mould Block, brake module and ECU；

   The radar is arranged on automotive front, for obtaining the distance between front vehicles and automobile, the speed of front vehicles, and Pass it to the signal integration module；

   The vehicle speed sensor, yaw-rate sensor, lateral acceleration sensor, front wheel angle sensor are respectively used to adopt Collect the speed of automobile, the yaw velocity of automobile, the side acceleration of automobile, the front wheel angle of automobile, and pass it to institute State signal integration module；

   The signal integration module respectively with radar, vehicle speed sensor, yaw-rate sensor, lateral acceleration sensor, Front wheel angle sensor, judge module, ECU are connected, for the Data Integration received to be input in ECU into working condition signal, And according to the speed of the front vehicles received, the speed of automobile, the yaw velocity of automobile, the side acceleration of automobile, vapour The front wheel angle of car calculates the steering safe distance and brake safe distance of automobile, by between front vehicles and automobile away from From passing to judge module with a distance from the steering safe distance and brake safe under, current working；

   The judge module be used for by the distance between front vehicles and automobile respectively with brake safe distance, turn to safe distance It is compared, and the result that draws will be compared and be input in ECU；

   The steering module includes wheel hub motor, for controlling automobile to be turned to；

   The brake module includes ABS, for controlling automobile to be braked；

   The ECU is also connected with the steering module, brake module respectively, for the comparative result control inputted according to judge module Steering module processed, brake module work.