JP2019098753A - Self-driving device and self-driving method - Google Patents

Abstract

To provide a self-driving device and a self-driving method capable of achieving a behavior of a vehicle similar to a feeling as if an occupant himself or herself was driving the vehicle even during a self-driving operation.SOLUTION: A self-driving device 1 includes: vehicle trajectory estimation means 2, 3, 4, and 6 for detecting a road status and estimating a trajectory ahead of a vehicle; left wheel speed detection means 5 for detecting a wheel speed of a left wheel of the vehicle; right wheel speed detection means 5 for detecting a wheel speed of a right wheel of the vehicle; wheel speed difference calculation means 6 for calculating a speed difference between the left wheel speed detected by the left wheel speed detection means 5 and the right wheel speed detected by the right wheel speed detection means 5; correction means 6 for correcting the trajectory estimated by the vehicle trajectory estimation means 2, 3, 4, and 6 using the speed difference detected by the wheel speed difference calculation means 6; and self-driving means 6, 7, 8, and 9 for self-driving the vehicle using the trajectory corrected by the correction means 6.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an automatic driving apparatus and an automatic driving method.

  In recent years, automatic driving techniques for vehicles have been developed. In this automatic driving control, for example, there is known a technology of automatically driving by recognizing a road condition using a camera or the like (see Patent Document 1). During execution of such automatic driving control, there is no driver (driver) in the vehicle, and it is not necessary to drive even an occupant (in the present specification, the occupant means a person on the vehicle) The case is assumed.

Patent 3339427 gazette

  However, in conventional automatic driving control, for a vehicle that turns a curve, adjustment of the steering angle is performed only when the vehicle is about to deviate from the lane. In addition, a vehicle traveling on a road having a water gradient is only required to adjust the steering angle after leaving a lane located outside the water gradient. Therefore, the trajectory of the vehicle in automatic driving tends to be largely different from the trajectory of the vehicle when the occupant actually drives, or the behavior of the vehicle becomes unstable due to a delay in control of the automatic driving. . As a result of these, there is a possibility that the occupant of the vehicle may feel a sense of discomfort in the difference between the feeling when driving by itself and the behavior of the vehicle in the case of automatic driving.

  The present invention has been made to solve at least a part of such a problem, and an object of the present invention is to realize a behavior of a vehicle similar to a feeling driven by a passenger even while driving automatically. An automatic driving device and an automatic driving method capable of

The present invention has been made to solve at least a part of the above-mentioned problems, and can be realized as the following aspects or application examples.
The automatic driving apparatus according to the application example includes: a vehicle locus estimation unit that detects a road condition and estimates a forward trajectory of the vehicle; a left wheel speed detection unit that detects a wheel velocity of a left wheel of the vehicle; Right wheel speed detecting means for detecting the wheel speed of the vehicle, and wheel speed difference calculating means for calculating a speed difference between the left wheel speed detected by the left wheel speed detecting means and the right wheel speed detected by the right wheel speed detecting means And correcting means for correcting the locus estimated by the vehicle locus estimating means using the speed difference calculated by the wheel speed difference calculating means, and automatic driving means for automatically driving the vehicle using the locus corrected by the correcting means. .

  On the other hand, the automatic driving method according to this application example includes a vehicle locus estimation step of detecting a road condition and estimating a locus in front of the vehicle, a left wheel speed detection step of detecting a wheel speed of the left wheel of the vehicle, and Wheel speed difference calculation that calculates the speed difference between the right wheel speed detection step that detects the wheel speed of the right wheel, the left wheel speed detected in the left wheel speed detection step, and the right wheel speed detected in the right wheel speed detection step A step of correcting the locus estimated in the vehicle locus estimation step using the speed difference detected in the wheel speed difference calculating step; and an automatic driving step for automatically driving the vehicle using the locus corrected in the correcting step including.

  With these automatic driving devices or automatic driving methods, it is possible to make the behavior of the vehicle as smooth as possible by a curve close to the trajectory of the vehicle when the occupant actually drives based on the wheel speed difference of the moving vehicle. The vehicle can be driven automatically while maintaining stability. Therefore, it is possible to realize the behavior of the vehicle close to the feeling of driving by the occupant even while driving automatically.

  The above-mentioned automatic driving device according to the application example further includes alarm output means for outputting an alarm when the speed difference detected by the wheel speed difference calculation means deviates from the predetermined range.

  On the other hand, the automatic driving method according to the application example further includes an alarm output step of outputting an alarm when the speed difference calculated in the wheel speed difference calculating step deviates from the predetermined range.

  With these automatic driving devices or automatic driving methods, when sudden changes in the behavior of the vehicle occur, the occupants can be alerted to prompt the next rapid treatment.

It is a block diagram showing composition of an automatic operation device concerning one embodiment of the present invention. It is a flowchart of automatic operation control. It is the figure which showed the map of the reference wheel speed parameter used by the initial stage learning of FIG.2 S1. It is a figure showing the map of the actual wheel speed parameter used by derivation of the actual locus of Step S6 of FIG. It is the figure which compared the locus | trajectory of the vehicle which bends the curve of a road by the past and this embodiment. It is the figure which compared the locus | trajectory of the vehicle which drive | works the road which has a water gradient by conventional and this embodiment.

  Hereinafter, an automatic driving apparatus according to an embodiment of the present invention will be described based on the drawings.

  FIG. 1 is a schematic block diagram of an automatic driving apparatus 1. The automatic driving apparatus 1 is mounted on a vehicle, includes a navigation apparatus 2, a radar apparatus 3, a camera apparatus 4, a vehicle state acquisition unit 5, a traveling control unit, and the like, and performs automatic driving control of the vehicle.

  The navigation device 2 has a function of detecting the position of the host vehicle, for example, can acquire GPS data, and has a map database including road information.

  The radar device 3 includes, for example, a millimeter wave radar and a laser radar, and detects an object such as another vehicle around the host vehicle. Specifically, it is possible to detect the inter-vehicle distance between the host vehicle and the preceding vehicle and the following vehicle by the radar device 3 or to detect a vehicle traveling on the side of the host vehicle.

  The camera device 4 includes, for example, a C-MOS camera and a CCD camera, recognizes lanes and water gradients of the road from captured images of these cameras, and prevents a vehicle from deviating from these, so-called lane keep assist function To realize.

  On the other hand, the vehicle state acquisition unit 5 can acquire vehicle information (vehicle state) such as the performance of the host vehicle, the traveling ability, the own weight, the loaded weight, the traveling route, and the current vehicle speed. More specifically, the performance of the host vehicle corresponds to, for example, performance parameters such as acceleration, output, maximum speed, and deceleration performance. This performance parameter changes according to the distance traveled and the age of the vehicle. The current vehicle speed includes not only the vehicle speed but also the left and right wheel speeds (rotational speed) of the front shaft (front drive shaft) for each steering angle while the vehicle is traveling, and the left and right wheel speeds of the rear shaft (rear drive shaft) Includes actual wheel speed parameters such as rotational speed).

  Thus, the navigation device 2, the radar device 3, and the camera device 4 have a function of detecting the road condition on which the vehicle travels. In addition, the navigation device 2, the radar device 3, the camera device 4, and the vehicle state acquisition unit 5 are electrically connected to the travel control unit 6. The travel control unit 6 is also electrically connected to the drive unit 7, the braking unit 8 and the steering unit 9 of the vehicle, and controls these units to control the behavior of the vehicle.

  The drive unit 7 is a part that drives the vehicle to travel, and is, for example, an engine, an electric motor, or both in the case of a hybrid vehicle.

  The braking unit 8 is a portion that brakes the vehicle, and includes, for example, a mechanical brake that generates a braking force by friction, an exhaust brake that generates a braking force other than friction, a retarder, a regenerative brake, and the like.

  The steering unit 9 is a part that steers the vehicle, and is, for example, a steering.

  The traveling control unit 6 is constituted by an ECU (Electronic Control Unit) and controls the whole of the automatic driving apparatus 1 and is mainly composed of a computer including a CPU (Central Processing Unit) and a RAM (Random Access Memory). It is configured.

  The automatic driving apparatus 1 according to the present embodiment performs traveling control based on not only the road conditions detected from the navigation apparatus 2, the radar apparatus 3, and the camera apparatus 4 but also the wheel speeds acquired by the vehicle state acquisition unit 5. The automatic driving control for adjusting the steering angle by controlling the steering unit 9 by the unit 6 is performed.

  Hereinafter, the automatic driving control executed by the traveling control unit 6 will be described with reference to the flowchart of FIG. 2. When this control is started, first, in step S1, initial learning of vehicle travel is performed. In this initial learning, the map of the reference wheel speed parameter is read into a memory such as the RAM of the traveling control unit 6.

  Specifically, as shown in FIG. 3, this map 10 is created from data of the front wheel left and right wheel speeds and the rear axis left and right wheel speeds for a predetermined steering angle. These data are reference values based on the specifications of the vehicle, and the reference wheel speed parameter is configured to be able to grasp the relationship between the steering angle specific to the vehicle and each wheel speed. In addition, the reference wheel speed parameter is appropriately updated to the latest data based on the above-described performance parameter accompanied by use and aging acquired by the vehicle state acquisition unit 5.

  Next, in step S2, a road condition is detected using each data acquired by the navigation device 2, the radar device 3 and the camera device 4, and the vehicle when the vehicle is headed forward next using the detected road condition The trajectory of the vehicle is estimated (vehicle trajectory estimation means, vehicle trajectory estimation step).

  Next, in step S3, a steering target is calculated using the forward trajectory of the vehicle estimated in step S2, the axle types of the front and rear axes, the wheel base representing the distance between the front and rear axes, the steering gear ratio, etc. Calculate the corners.

  Next, in step S4, the steering unit 9 is controlled using the steering target angle calculated in step S3 to execute automatic steering of the vehicle. The drive unit 7 and the braking unit 8 may be controlled together at the time of the automatic steering.

  Next, in step S5, the left and right wheel speeds of the front axis and the left and right wheel speeds of the rear axis of the traveling vehicle are detected as actual wheel speed parameters via the vehicle state acquisition unit 5 (left wheel speed detection means, left wheel Speed detection step, right wheel speed detection means, right wheel speed detection step).

  Next, in step S6, the wheel speed difference between the left and right wheels in the front and rear axes is calculated using the actual wheel speed parameters acquired in step S5 (wheel speed difference calculating means, wheel speed difference calculating step). Then, from the calculated wheel speed difference, the traveling locus of the vehicle actually traveling is derived as an actual locus.

  Specifically, as shown in FIG. 4, the actual trajectory is derived using the map 11 of the actual wheel speed parameters stored in advance in the memory such as the RAM of the traveling control unit 6. The map 11 shows the vehicle speed, the right and left wheel speeds of the front axle, and the left and right of the rear axle with respect to a predetermined traveling state (straight running, R20 left turn, R20 right turn, etc.) of the vehicle when the occupant actually drives. It is created from data of the wheel speed, and is configured to be able to grasp the relationship between the traveling state of the vehicle including the steering angle and each wheel speed.

  Further, in step S6, a deviation between the actual locus derived from the map 11 and the estimated locus acquired in step S2 is detected, and the steering unit 9 is controlled to correct this deviation in a direction to eliminate it. That is, in step S6, the estimated trajectory obtained in step S2 is continuously corrected using the wheel speed difference between the left and right wheels of the front and rear axes of the running vehicle (correction means, correction step). Automatic steering and thus automatic driving of the vehicle via the steering unit 9 are executed using a locus close to the actual locus based on the map 11 of the actual wheel speed parameters (automatic driving means, automatic driving step). It should be noted that the drive unit 7 and the braking unit 8 may be controlled together when correcting the deviation of the locus.

  Next, in step S7, it is determined whether to stop the automatic driving control. If the determination result is "Yes", this control ends. On the other hand, if the determination result is No, the process proceeds to step S2, and the above-described steps S2 to S6 are performed again.

  When the wheel speed difference between the left and right wheels at the front and rear axes calculated in step S6 deviates from the predetermined range, the process proceeds to step S8 and an alarm is output (alarm output means).

  As described above, the automatic driving apparatus 1 and the automatic driving method according to the present embodiment correct the vehicle trajectory estimated based on the information of the road condition using the wheel speed difference between the left and right wheels of the traveling vehicle and correct the vehicle trajectory. Automatic driving of the vehicle is performed using the trajectory. Therefore, the sense of incongruity between the feeling when the occupant is driving and the behavior of the vehicle in the case of automatic driving is eliminated, and the behavior of the vehicle similar to the feeling driven by the occupant is realized even during automatic driving. be able to.

  Specifically, as shown in FIG. 5, in the case of the conventional case, the vehicle 13 which bends the curve of the road 12 performs the adjustment of the steering angle only when the vehicle 13 is about to deviate from the lane 14. Therefore, when the vehicle 13 travels straight and reaches an arrival point P which is likely to deviate from the lane 14, the vehicle 13 travels in a stepwise, polygonal trajectory 15 (indicated by a broken arrow) that changes its direction when it hits a wall. Do.

  On the other hand, according to the automatic driving system 1 of the present embodiment, the estimated trajectory based on the road condition is corrected using the map 11 of the actual wheel speed parameter, based on the wheel speed difference of the traveling vehicle 13 It is possible to realize traveling of the vehicle 13 on a locus 16 (indicated by a solid arrow) that is a smooth curve close to the actual locus of the vehicle 13 when the occupant actually drives.

  Also, as shown in FIG. 6, in the conventional case, the vehicle 13 traveling on the road 12 having the water gradient 17 is not subjected to the adjustment of the steering angle only after the vehicle 13 is shifted to the lane 14 located outside the water gradient 17. . As described above, when a delay occurs in the control of the automatic driving, the trajectory 18 (shown by a broken arrow) on which the vehicle 13 travels becomes stepwise, and the behavior of the vehicle 13 when a plurality of wheels reach the water gradient 17 Becomes unstable.

  On the other hand, according to the automatic driving system 1 of the present embodiment, at the moment when one wheel reaches the water gradient 17 by correcting the estimated trajectory based on the road condition using the map 11 of the actual wheel speed parameter, Adjustment of the steering angle can be performed before the vehicle 13 actually gets off either side of the lane 14 based on the wheel speed difference. Therefore, while maintaining the behavior of the vehicle 13 as stably as possible, it is possible to realize the traveling of the vehicle 13 on the smooth curved trajectory 19 (indicated by a solid arrow).

  Further, when the wheel speed difference between the left and right wheels at the front and rear axes calculated at step S6 deviates from the predetermined range, the automatic driving apparatus 1 of the present embodiment proceeds to step S8 and outputs an alarm. As a result, for example, when an accident such as a puncture occurs and a sudden change in the behavior of the vehicle occurs, the occupant can be alerted to prompt the next rapid treatment. In addition, even when the vehicle travels on a step or a heel and a sudden change occurs in the behavior of the vehicle, the automatic driving control can automatically correct the behavior of the vehicle in a stable direction.

  Further, by realizing the behavior of the vehicle close to the sense of driving by the occupant during automatic driving by the automatic driving device 1, it is possible to obtain a feeling that the passenger is driving even in automatic driving. Thereby, the reliability and sense of security for automatic driving control of the vehicle can be improved, and the fatigue of the occupant based on the conventional discomfort can be reduced.

  In addition, by reducing unnecessary operation related to automatic steering, it is possible to improve controllability including responsiveness of automatic driving control.

  This completes the description of the embodiments of the present invention, but the aspects of the present invention are not limited to this embodiment.

  For example, in the automatic driving device 1 and the automatic driving method of the above embodiment, initial learning of vehicle travel is performed in step S1, but this initial learning is not necessarily required, and control is started from estimation of the vehicle trajectory in step S2. You may.

  Moreover, you may use apparatuses other than the navigation apparatus 2, the radar apparatus 3, and the camera apparatus 4 in the detection of the road condition performed by step S2.

  Further, as described above, the automatic driving device 1 and the automatic driving method can be used for detecting an accident and maintaining the behavior of a vehicle other than automatic steering. In addition, by controlling the drive unit 7 and the braking unit 8 together when controlling the steering unit 9, it is also possible to realize comprehensive automatic driving of the vehicle.

  Moreover, although the automatic driving apparatus 1 and the automatic driving method are applicable to the vehicle which mounts an engine, an electric motor, or both as the drive part 7 as mentioned above, the driving control system of a vehicle is not restricted to this. The invention is also applicable to vehicles in which all of them are replaced by so-called drive by wire.

  Moreover, the automatic driving device 1 and the automatic driving method can be applied to various vehicles such as a passenger car and a truck.

  In addition, the automatic driving device 1 and the automatic driving method are applied to various vehicles such as a steering unit 9 which can be operated by a passenger, that is, a vehicle provided with a steering, a vehicle which can not be driven by an occupant, ie, a steering is not provided. It is possible.

1 Automatic driving device 2 Navigation device (vehicle trajectory estimation means)
3 Radar device (vehicle trajectory estimation means)
4 Camera device (vehicle trajectory estimation means)
5 Vehicle condition acquisition unit (left wheel speed detection means, right wheel speed detection means)
6 Travel control unit (vehicle trajectory estimation means, wheel speed difference calculation means, correction means, automatic driving means, alarm output means)
7 Drive unit (automatic operation means)
8 Braking unit (automatic driving means)
9 Steering unit (automatic driving means)

Claims (4)

Vehicle trajectory estimation means for detecting a road condition and estimating a forward trajectory of the vehicle;
Left wheel speed detection means for detecting the wheel speed of the left wheel of the vehicle;
Right wheel speed detection means for detecting the wheel speed of the right wheel of the vehicle;
Wheel speed difference calculating means for calculating a speed difference between the left wheel speed detected by the left wheel speed detecting means and the right wheel speed detected by the right wheel speed detecting means;
Correction means for correcting the locus estimated by the vehicle locus estimation means using the speed difference calculated by the wheel speed difference calculation means;
And an automatic driving means for automatically driving the vehicle using the locus corrected by the correction means.   The automatic driving device according to claim 1, further comprising alarm output means for outputting an alarm when the speed difference detected by the wheel speed difference calculation means deviates from a predetermined range. A vehicle trajectory estimation step of detecting a road condition and estimating a forward trajectory of the vehicle;
A left wheel speed detection step of detecting a wheel speed of the left wheel of the vehicle;
A right wheel speed detection step of detecting a wheel speed of the right wheel of the vehicle;
A wheel speed difference calculating step of calculating a speed difference between the left wheel speed detected in the left wheel speed detecting step and the right wheel speed detected in the right wheel speed detecting step;
A correction step of correcting the locus estimated in the vehicle locus estimation step using the speed difference detected in the wheel speed difference calculation step;
And d) automatically driving the vehicle using the locus corrected in the correcting step.   The automatic driving method according to claim 3, further comprising an alarm output step of outputting an alarm when the speed difference calculated in the wheel speed difference calculating step deviates from a predetermined range.

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