CN108995708A - Automatic turning control method and device for vehicle - Google Patents

Abstract

The invention provides an automatic turning control method for a vehicle, which comprises the following steps: judging whether the vehicle is in a turnable working condition; prompting a driver to activate an automatic turning mode under the condition that the vehicle is in a turnable working condition; in response to activation of the automatic turn mode, performing the steps of: (a) fitting the target running track of the vehicle according to the motion track points of the front vehicle; (b) determining a transverse control parameter and a longitudinal control parameter of the vehicle based on the target running track and the current running track of the vehicle; and (c) turning the vehicle along the target running track according to the transverse control parameter and the longitudinal control parameter. In addition, the invention also provides a corresponding automatic turning control device of the vehicle.

Description

A vehicle automatic turning control method and device

technical field

The present invention generally relates to the technical field of automatic driving, and in particular, relates to a solution for vehicle adaptive control.

Background technique

At this stage, vehicle control technology is developing towards the direction of "smart vehicles". On the basis of ordinary vehicles, more and more advanced sensors, controllers, actuators and other devices are added, so that the vehicles have intelligent environmental perception capabilities, can automatically analyze the safety and dangerous status of vehicles, and make the vehicles follow human requirements. Willing to reach the destination, and finally realize the purpose of replacing human beings to operate.

In the current driving assistance system, the road environment is one of the main information of sensor environment perception. However, most driver assistance systems are only suitable for traffic scenes with clear lane lines, such as highways. On complex urban roads, such as intersections without lane lines, it is difficult for vehicles to automatically stop and turn. These issues lead to limited automation of driver assistance systems, poor driving experience, and low usage.

Therefore, it is desirable to design a vehicle driving assistance scheme suitable for urban traffic scenarios.

Contents of the invention

In view of this, the present invention provides a method for controlling automatic turning of a vehicle, which includes: judging whether the vehicle is in a turning condition; prompting the driver to activate the automatic turning mode when the vehicle is in a turning condition; The activation of the turning mode performs the following steps: (a) fitting the target trajectory of the vehicle according to the trajectory points of the preceding vehicle; (b) determining the lateral control parameters of the vehicle based on the target trajectory and the current trajectory of the vehicle and longitudinal control parameters; and (c) making the vehicle turn along the target trajectory according to the lateral control parameters and the longitudinal control parameters.

The above method, wherein judging whether the vehicle is in a turnable condition includes determining that the vehicle is in a turnable condition when it is detected that the vehicle in front turns on the turn signal, the vehicle enters a designated turning area, and the traffic signal light is green.

The method as described above, wherein, when the vehicle in front starts to turn on the turn signal, the movement trajectory points of the vehicle in front are collected, and in response to the activation of the automatic turning mode, the deviation between the movement trajectory of the vehicle in front and the lateral position of the own vehicle exceeds a predetermined threshold start to fit the target driving trajectory.

The method as described above, further comprising enabling the driver to activate the automatic turning mode by turning on the turn signal.

The method as described above, wherein the target driving trajectory is fitted using the own vehicle coordinate system at the moment when the vehicle in front is detected to turn on the turn signal as the global coordinate system, and wherein the vehicle is determined based on the target driving trajectory and the current driving trajectory The lateral control parameters and longitudinal control parameters include comparing the target driving trajectory with the current driving trajectory in the global coordinate system.

The method as described above, wherein fitting the target driving trajectory includes fitting the movement trajectory points of the preceding vehicle into a polynomial function in the global coordinate system as the target driving trajectory.

The above-mentioned method, wherein, the current driving trajectory is determined according to the wheel speed pulse, steering wheel angle, vehicle speed and the physical size of the vehicle and is positioned in the global coordinate system.

The above method, wherein determining the longitudinal control parameters includes: determining the maximum lateral acceleration of the vehicle according to the curvature of the target driving trajectory; and determining the vehicle speed of the own vehicle according to the maximum lateral acceleration.

The method as described above, wherein determining the lateral control parameters includes: determining the ideal steering wheel angle according to the curvature of the target driving trajectory; determining the adjustment value of the steering wheel angle according to the lateral distance deviation and the attitude angle deviation between the current driving trajectory and the target driving trajectory; and using The adjustment value corrects the ideal steering wheel angle to obtain the actual steering wheel angle of the vehicle.

The above method, wherein after adjusting the driving state of the own vehicle according to the longitudinal control parameters, the driving state of the own vehicle is adjusted according to the lateral control parameters, so as to control the own vehicle to turn along the target driving trajectory.

On the other hand, the present invention also provides a vehicle automatic turning control device, the vehicle automatic turning control device includes a memory, a processor and a computer program stored on the memory, wherein, when executed on the processor The computer program causes the vehicle automatic turning control device to execute the above-mentioned method.

Description of drawings

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of embodiments of the invention, illustrated in the accompanying drawings.

Fig. 1 is a flow chart of a vehicle automatic turning control method according to an example of the present invention.

Fig. 2 is an application scenario of a vehicle automatic turning control method according to an example of the present invention.

Fig. 3 is a block diagram of a vehicle automatic turning control device according to an example of the present invention.

Detailed ways

Illustrative examples of the invention will now be described with reference to the drawings, wherein like reference numerals refer to like elements. Each example described below helps those skilled in the art to thoroughly understand the present invention, and each example is intended to be an illustration rather than a limitation. The illustrations of the components, components, modules, devices and equipment bodies in the figure only schematically indicate the existence of these components, components, modules, devices and equipment bodies, and also indicate the relative relationship between them, but are not intended to limit their specific Shape; the relationship of each step in the flow chart is not limited to the order given, and can be adjusted according to actual applications without departing from the scope of protection of the present application.

As mentioned in the background technology, in complex urban roads, without lane line information, it will be difficult for vehicles to realize automatic stop and turn, especially in most vehicles that are not equipped with high-precision maps and Global Positioning System GPS case. The present invention provides a vehicle assisted driving solution, which can realize automatic turning control of vehicles in urban traffic scenarios without the need for high-end assisted navigation configurations such as high-precision maps and GPS.

The vehicle assisted driving solution provided by the present invention can replace the driver to assume the responsibility of controlling the vehicle for a period of time, especially when turning is required. According to the method of the present invention, the vehicle will have longitudinal and lateral automatic control at the same time, but the driver still needs to monitor the driving activity, that is, observe the surrounding situation, and the driver can share the control right with the vehicle, and must be on call at any time. It can be connected at any time when the vehicle is out of automatic control.

Fig. 1 is a flow chart of a vehicle automatic turning control method according to an example of the present invention. As shown in FIG. 1 , the method first includes judging in step 11 whether the vehicle is in a turnable condition. In the context of the present invention, a turning condition refers to a road condition in which the vehicle can turn.

In some embodiments, judging whether the vehicle is in a turning state includes determining that the vehicle is in a turning state when it is detected that the vehicle in front turns on the turn signal, the vehicle enters a designated turning area, and the traffic signal light is green. In implementation, one or more front-facing cameras arranged on the vehicle body can be used to detect the distance of traffic lights, thereby judging whether the vehicle enters a designated turning area. In addition, the front camera can also be used to detect the state of the traffic signal light, and one of the conditions that the vehicle can be considered to be in a turnable state is satisfied when the traffic signal light is green. In addition, whether the vehicle in front turns on the turn signal can also be used as an important condition for judging whether the vehicle is in a turnable condition, which will be described in detail below.

Those skilled in the art will understand that the determination of this turnable operating condition is not limited to the situation in the above examples. For example, in the current right-turn situation, it may not be necessary to judge the state of the traffic lights, but only by determining whether the vehicle is in a designated turning area (such as a right-turn lane) to determine whether the vehicle is in a turnable condition.

Further, if the environmental conditions are satisfied, that is, the vehicle is in a road condition where turning is possible, the driver may be prompted to activate the automatic turning mode in step 12, and it is determined in step 13 whether the automatic turning mode is activated. In some examples, the driver may be enabled to activate the auto-turn mode by turning on the turn signal, and it may be determined that the auto-turn mode may be entered in response to activation of the turn signal. In some other examples, the driver can also activate the automatic turning mode by setting a special mode start/switch button.

Steps 14 to 16 are performed with the auto turn mode activated. As shown in FIG. 1 , in step 14 , the target driving trajectory of the vehicle is fitted according to the movement trajectory points of the preceding vehicle. In some examples, the movement track points of the preceding vehicle may be continuously collected. In some other examples, the collection of motion track points of the vehicle in front may be started when the vehicle in front starts to turn on the turn signal. In some embodiments of the present invention, it may be considered as an important time node when the vehicle in front starts to turn on the turn signal. In addition to collecting the movement track points of the vehicle in front at this moment, the coordinate system of the own vehicle at the moment when the vehicle in front is detected to turn on the turn signal can also be used as the global coordinate system. On the one hand, the target driving trajectory of the vehicle can be fitted in the global coordinate system. On the other hand, the subsequent moving trajectory of the vehicle can also be controlled based on the global coordinate system.

Fig. 2 is an application scenario of a vehicle automatic turning control method according to an example of the present invention, that is, a situation where the vehicle turns right at a crossroad. In FIG. 2, the vehicle located below is the host vehicle, and the vehicle located above is the front vehicle. If the scene shown in Figure 2 is considered as the moment when the vehicle in front starts to turn on the turn signal, then the Cartesian coordinate system drawn according to the orientation of the vehicle is considered as the global coordinate system. is the x-axis, and the direction perpendicular to the body is the y-axis. In some embodiments, the target driving trajectory of the vehicle will be fitted in this global coordinate system, and the subsequent moving trajectory of the vehicle will be characterized by using the global coordinate system as a reference.

In some examples, fitting the target driving trajectory may start when the deviation between the movement trajectory of the preceding vehicle and the lateral position of the host vehicle exceeds a predetermined threshold. Taking the scene shown in Fig. 2 as an example, the length marked with d can be regarded as the lateral position deviation between the movement track of the preceding vehicle and the own vehicle. As mentioned above, the calculation of the lateral position deviation can be performed in the global coordinate system. That is to say, the collected track points of the preceding vehicle can be expressed in the global coordinate system, and the real-time position of the own vehicle can also be expressed in the global coordinate system, thereby determining the lateral position deviation between the two.

In some examples, the trajectory points of the preceding vehicle may be fitted to a polynomial function in the global coordinate system as the target trajectory of the vehicle. The polynomial function used can be selected according to the specific target scene, for example, a quadratic function, a cubic function, and the like.

In step 15, the lateral control parameters and longitudinal control parameters of the vehicle are determined based on the target driving trajectory and the current driving trajectory of the vehicle. In some examples, the step of determining the lateral control parameter and the longitudinal control parameter may include comparing the target driving trajectory with the current driving trajectory in the global coordinate system. For example, the distance deviation and attitude angle deviation of the vehicle from the target trajectory line can be used, wherein the distance deviation can include lateral and longitudinal distances, and the attitude angle deviation can refer to the tangential angle between the extension line in the direction of the vehicle head and the target driving trajectory.

In some examples, the current driving trajectory of the vehicle can be determined according to the wheel speed pulse, steering wheel angle, vehicle speed and physical size of the vehicle, and the current driving trajectory can be positioned in the global coordinate system, so as to adjust the control parameters in real time so that The current driving trajectory conforms to the target driving trajectory. In an implementation, the wheel speed pulses may eg be the output of a wheel speed sensor. Those skilled in the art can understand that the current driving trajectory of the vehicle can be determined according to any known or future available method, and is not limited to the description herein.

In some examples, the maximum lateral acceleration of the vehicle may be determined according to the curvature of the target driving trajectory and the vehicle speed of the host vehicle may be determined according to the maximum lateral acceleration. Vehicle speed can be considered as a longitudinal control parameter. Within the range limited by the maximum lateral acceleration, the vehicle speed required for the turning process can be determined comprehensively considering driving comfort and safety, and the vehicle can be kept at this speed to drive at a constant speed.

In some examples, the ideal steering wheel angle of the vehicle may also be determined according to the curvature of the target driving trajectory, that is, the turning radius of the preceding vehicle. In order to more accurately generate the steering wheel angle request, the adjustment value of the steering wheel angle can also be determined according to the lateral distance deviation and the attitude angle deviation between the current driving trajectory and the target driving trajectory, and finally the ideal steering wheel angle is corrected by using the adjustment value to obtain The actual steering wheel angle of the vehicle. In some cases, this can be understood as a feedback adjustment process. Steering wheel angle can be considered as a lateral control parameter. The error between the driving trajectory and the target trajectory can be reduced by lateral control, so as to ensure that the vehicle travels along the target trajectory.

Finally, in step 16, according to the lateral control parameter and the longitudinal control parameter, the vehicle is turned along the target driving track. In some examples, the driving state of the vehicle can be adjusted according to the longitudinal control parameters such as vehicle speed first, and then adjusted according to the lateral control parameters such as the steering wheel angle, thereby controlling the vehicle to turn along the target driving trajectory. Through such decoupling control of vertical and lateral dynamics, especially the decoupling of vehicle acceleration and deceleration motion and steering motion, the experience of automatic steering conforms to the driver's normal driving habits, and prevents the vehicle from rolling over when the vehicle is too fast during the turning process. Even at a constant speed, it can ensure the accuracy, real-time and stability of the lateral control of the vehicle.

The vehicle automatic turning control method provided by the present invention can be applied to rich urban traffic scenes, so that the driver can realize fully automatic driving when turning, and is not limited by whether the vehicle has high-end navigation configuration.

Fig. 3 is a block diagram of a vehicle automatic turning control device according to an example of the present invention. As shown in Figure 3, the vehicle automatic turning control device 300 includes a memory 31 and a processor 33, wherein computer programs are stored on the memory 31, and when these computer programs are executed by the processor 33, the vehicle automatic turning control device can execute As mentioned above, the vehicle automatic turning control method according to the present invention.

The vehicle automatic turning control device 300 can be implemented separately, or integrated in the electronic control unit ECU of the vehicle. In the latter case, the device 300 can be implemented by sharing the processor and memory in the ECU.

It should be noted that the above specific embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above specific embodiments, those skilled in the art should understand that the specific embodiments of the present invention can still be modified or some technical features can be equivalently replaced without departing from the essence of the present invention. All fall within the scope of protection claimed by the present invention.

Claims (11)

1. A vehicle automatic turning control method, comprising: Determine whether the vehicle is in a turning condition; Prompt the driver to activate the automatic turning mode when the vehicle is in a turnable condition; The following steps are performed in response to activation of the auto turn mode: (a) Fit the target trajectory of the vehicle according to the trajectory points of the vehicle in front; (b) determining a lateral control parameter and a longitudinal control parameter of the vehicle based on the target driving trajectory and the current driving trajectory of the vehicle; and (c) making the vehicle turn along the target trajectory according to the lateral control parameter and the longitudinal control parameter. 2. The method according to claim 1, wherein judging whether the vehicle is in a turnable condition comprises judging that the vehicle is in a turning state when it is detected that the vehicle in front turns on the turn signal, the vehicle enters a designated turning area, and the traffic signal light is green. Turnable conditions. 3. The method as claimed in claim 1, wherein, when the vehicle in front starts to turn on the turn signal, the movement track points of the vehicle in front are collected, and in response to the activation of the automatic turning mode, the movement track of the vehicle in front and the lateral direction of the vehicle When the position deviation exceeds a predetermined threshold, fitting the target driving trajectory starts. 4. The method of claim 1, further comprising enabling a driver to activate the auto-turn mode by turning on a turn signal. 5. The method as claimed in claim 1, wherein, the vehicle coordinate system at the time when the vehicle in front is detected to turn on the turn signal is used as the global coordinate system to fit the target driving trajectory, and wherein, based on the target driving trajectory and the current Determining the lateral control parameters and longitudinal control parameters of the own vehicle on the driving trajectory includes comparing the target driving trajectory with the current driving trajectory in the global coordinate system. 6. The method according to claim 5, wherein fitting the target driving trajectory comprises fitting the movement trajectory points of the preceding vehicle into a polynomial function in the global coordinate system as the target driving trajectory. 7. The method according to claim 5, wherein the current driving trajectory is determined according to wheel speed pulses, steering wheel angle, vehicle speed and physical size of the own vehicle and is positioned in the global coordinate system. 8. The method of claim 1, wherein determining longitudinal control parameters comprises: determining the maximum lateral acceleration of the vehicle according to the curvature of the target travel trajectory; and The vehicle speed of the own vehicle is determined according to the maximum lateral acceleration. 9. The method of claim 1, wherein determining lateral control parameters comprises: Determine the ideal steering wheel angle according to the curvature of the target driving trajectory; Determine the adjustment value of the steering wheel angle according to the lateral distance deviation and the attitude angle deviation between the current driving trajectory and the target driving trajectory; and The ideal steering wheel angle is corrected with the adjustment value to obtain the actual steering wheel angle of the vehicle. 10. The method according to claim 1, wherein after the driving state of the own vehicle is adjusted according to the longitudinal control parameters, the driving state of the own vehicle is adjusted according to the lateral control parameters, so as to control the own vehicle to turn along the target driving trajectory. 11. An automatic turning control device for a vehicle, the automatic turning control device for a vehicle comprising a memory, a processor and a computer program stored on the memory, wherein when the computer program is executed on the processor, the The vehicle automatic turning control device executes the method according to any one of claims 1-10.