JP5158514B2 - vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably follow a preceding vehicle while traveling side-by-side with it. <P>SOLUTION: A following vehicle 3 follows the preceding vehicle 2 while traveling side-by-side with it by carrying out longitudinal direction control and lateral direction control. In the longitudinal direction control, feedback control and feedforward control are performed. In the feedforward control, a value found by correcting a target vehicle speed sent from the preceding vehicle 2 with an increase/decrease of a speed of the following vehicle 3 traveling the inner/outer circumference of the preceding vehicle 2 is used when the preceding vehicle 2 turns. In the lateral directional control, an azimuth &phiv; and a relative angle &theta; are converged to each other. In this process, by using a target distance &Delta;m from a representative point 7 of the own vehicle to a target point 5 for the preceding vehicle 2, the following vehicle 3 determines which of the azimuth &phiv; and the relative angle &theta; is controlled preferentially. When the target distance &Delta;m is small, that is, when the following vehicle 3 and the preceding vehicle 2 are close to each other, a gain for controlling the azimuth &phiv; is reduced. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a vehicle, and for example, relates to a follow-up running that runs in parallel with another vehicle based on a command from another vehicle or the host vehicle.

When a vehicle travels, a vehicle that auto-cruises following a preceding vehicle (hereinafter referred to as a preceding vehicle) has been proposed.
For example, in the following Patent Document 1, in a single-seat vehicle capable of traveling independently, the preceding vehicle travels as a host vehicle, while the other vehicle travels side by side as the following vehicle alongside the host vehicle. The case has been proposed.
JP 2006-338117 A

Hereinafter, conventional tracking control will be described.
FIG. 10A is a diagram for explaining a case where the following vehicle 3 runs side by side on the left side in the traveling direction of the preceding vehicle 2.
The following vehicle 3 sets a target point 5 at a position a lateral distance a from the representative point 6 of the preceding vehicle 2.
Then, the following vehicle 3 calculates the front-rear deviation Δd in the front-rear direction (traveling direction, vertical direction) and the left-right deviation Δw in the left-right direction (lateral direction) between the representative point 7 of the own vehicle and the target point 5. The vehicle speed and turning of the host vehicle are feedback controlled so that the deviation converges to zero.

FIG. 10B is a block diagram of feedback control for converging Δd.
The following vehicle 3 has a vehicle speed command value uFB obtained by multiplying Δd by a proportional coefficient kp1, and time-differentiating Δd (“s” indicates differentiation) and multiplying this by a proportional coefficient kd1. And the vehicle speed is feedback-controlled using this (PD control in this example).
The vehicle speed command value uFB is a command related to the vehicle speed, such as a target vehicle speed, an acceleration command, or a target acceleration based on an accelerator opening, and is a front-rear direction command value related to the movement of the following vehicle 3 in the front-rear direction.

FIG. 10C is a block diagram of feedback control for converging Δw.
The following vehicle 3 generates a turning direction command value uLR by adding Δw multiplied by the proportional coefficient kp2 and time-differentiating Δw and multiplying this by the proportional coefficient kd2, thereby generating the following The turning of the vehicle 3 is feedback controlled.
The left-right direction command value uLR is a command related to turning, such as a turning angle command, a steering wheel steering angle, and the like, and is a left-right direction command value related to movement of the following vehicle 3 in the left-right direction (lateral direction).

  However, since feedback control is performed only after a deviation has occurred, the response is slow in certain cases, such as when the vehicle is running close together and turning while traveling at high speed, and tracking control can be performed sufficiently. There was no problem.

  Then, an object of this invention is to provide the vehicle which can carry out the stable parallel run following with respect to a preceding vehicle.

(1) In order to achieve the above object, according to the first aspect of the present invention, the vehicle performs parallel running following the preceding vehicle, and acquires a target point for following the preceding vehicle. Point acquisition means, feedback means for performing feedback control on the deviation from the acquired target point, vehicle speed control information acquisition means for acquiring vehicle speed control information for controlling the vehicle speed of the preceding vehicle, and the acquired Using the correction means for correcting the control amount defined by the vehicle speed control information by using the increase / decrease amount of the vehicle speed required when turning while running parallel to the preceding vehicle, and using the control amount corrected by the correction means Provided is a vehicle characterized by comprising feedforward means for performing feedforward control.
(2) In the invention described in claim 2, when the preceding vehicle turns, distance acquisition means for acquiring a distance from the preceding vehicle, angular velocity acquisition means for acquiring an angular velocity of a turn performed by the preceding vehicle, and Determining means for determining whether the host vehicle travels on an inner periphery or an outer periphery, wherein the correction means acquires a correction amount using the acquired distance and angular velocity, and the determination means includes an outer periphery. When it is determined that the vehicle travels, the control amount is increased by the correction amount, and when the determination unit determines to travel on the inner circumference, the control amount is decreased by the correction amount. A vehicle according to claim 1 is provided.
(3) In the invention according to claim 3, the vehicle speed control information is acceleration information of the preceding vehicle, and the correction means obtains a correction amount by differentiating a product of the obtained distance and angular velocity, The vehicle according to claim 2, further comprising a mitigating means for mitigating a sudden change in the correction amount due to the differentiation.
(4) In the invention according to claim 4, azimuth angle obtaining means for obtaining an azimuth angle from the own vehicle to the obtained target point, and a relative angle for obtaining a relative angle formed by the traveling direction of the own vehicle and the preceding vehicle. Angle acquisition means and control target angle acquisition means for acquiring a control target angle using the acquired azimuth angle and relative angle, and the feedback means feeds back so that the acquired control target angle converges. The vehicle according to any one of claims 1, 2, and 3 is controlled.
(5) In invention of Claim 5, it comprises the target point distance acquisition means which acquires the target point distance from the own vehicle to the acquired target point, and the control object angle acquisition means includes the acquired target point. 5. The vehicle according to claim 4, wherein the greater the distance, the greater the degree of contribution of the acquired azimuth angle to the control target angle.
(6) The invention according to claim 6 provides the vehicle according to claim 5, wherein an upper limit is provided for the degree of contribution of the azimuth angle to the angle to be controlled.
(7) In the invention described in claim 7, turning control information acquisition means for acquiring turning control information for controlling turning from the preceding vehicle, and the control target angle using the acquired turning control information. The vehicle according to claim 4, claim 5, or claim 6, further comprising turning feedforward means for performing feedforward control.

  According to the present invention, the vehicle speed control information for controlling the vehicle speed of the preceding vehicle is acquired, and the control amount defined by the acquired vehicle speed control information is corrected using the increase / decrease amount of the vehicle speed necessary for turning. Since feedforward control is performed using the corrected control amount, stable parallel running following with respect to the preceding vehicle becomes possible.

(1) Outline of Embodiment The following vehicle 3 (FIG. 2) performs parallel running following traveling with respect to the preceding vehicle 2 by performing control in the front-rear direction and control in the left-right direction.
In the front-rear direction control, feedback control for converging the deviation from the target point set on the side of the preceding vehicle 2 to zero and feedforward control for compensating for a delay in the response of the feedback control are performed. In the feedforward control, the target vehicle speed (or target acceleration) transmitted from the preceding vehicle 2 is increased or decreased when the following vehicle 3 travels on the inner and outer circumferences of the preceding vehicle 2 when the preceding vehicle 2 turns. Use the value corrected in.
In the left-right control, the azimuth angle φ and the relative angle θ (FIG. 4) are converged. At this time, the following vehicle 3 determines which of φ and θ is preferentially controlled using the target point distance Δm from the representative point 7 of the own vehicle to the target point 5 with respect to the preceding vehicle 2.
Furthermore, when the target point distance Δm is small, that is, when the follower vehicle 3 and the preceding vehicle 2 are close to each other, in order to avoid the contact between the follower vehicle 3 and the preceding vehicle 2 by rapidly changing φ, Reduce the gain when controlling φ.

(2) Details of Embodiment The vehicle of the present embodiment can be applied to a normal four-wheel vehicle, but particularly when applied to a small vehicle having a high degree of lateral turning freedom. It is valid.
Therefore, in this embodiment, a case where the present invention is applied to an inverted pendulum vehicle (such as a single-shaft two-wheel vehicle) that can turn with a small radius will be described as an example. Although the preceding vehicle will be described as an inverted pendulum vehicle, other four-wheel vehicles may be used.

  The inverted pendulum vehicle travels while sensing the posture of the riding section and performing posture control so as to maintain the balance in the front-rear direction in the driving direction of the drive wheels in accordance with the posture. As the attitude control method, for example, various controls disclosed in US Pat. No. 6,302,230, JP-A 63-35082, JP-A 2004-129435, and JP-A 2004-276727 are disclosed. The method can be used.

FIG. 1 shows a configuration related to the follow-up control of the vehicle (follow-up vehicle 3) of the present embodiment.
As shown in FIG. 1, the following vehicle 3 includes an ECU (Electronic Control Unit) 10, a laser radar 20, a vehicle speed sensor 30, a yaw rate sensor 40, a wireless communication device 50, and drive motors 60a and 60b. .
Although not shown, a battery is also provided that supplies drive power to the drive motors 60a and 60b and the like, and supplies a low-voltage power supply for control to the ECU 10.

The ECU 10 includes a computer system including a ROM that stores various programs and data (not shown), a RAM that is used as a work area, an external storage device, an interface unit, and the like.
In the present embodiment applied to an inverted pendulum vehicle, a posture control program for maintaining the posture, a travel control program for controlling travel based on various instruction signals from the control device, and following the preceding vehicle 2 in the present embodiment. Various programs such as a follow-up traveling program for traveling are stored in the ROM, and the ECU 10 performs corresponding processing by executing these various programs.

The ECU 10 also includes a preceding vehicle relative position detection unit 11, a follow-up control unit 12, and a vehicle control unit 13.
The preceding vehicle relative position detection unit 11 detects the relative position and direction (traveling direction) of the preceding vehicle 2 based on the position and distance measured by the laser radar 20, and supplies them to the follow-up control unit 12.
Note that the vehicle speed and yaw rate information may be received from the preceding vehicle 2 by communication.
Further, although not required in the present embodiment, when receiving position coordinate data from the preceding vehicle 2 and performing dead reckoning, a current position such as GPS is used to detect the absolute position of the host vehicle (following vehicle 3). You may make it provide a detection apparatus.

The follow-up control unit 12 supplies the vehicle control unit 13 with control command values (front-rear direction command value, left-right direction command value) when performing parallel running follow-up as follow-up running in the present embodiment.
The follow-up control unit 12 acquires the vehicle speed from the vehicle speed sensor 30 and the yaw rate from the yaw rate sensor 40. Further, the target command value of the preceding vehicle 2 received by the wireless communication device 50 is acquired. The wireless communication device 50 transmits / receives data to / from the preceding vehicle 2 and other vehicles (including following vehicles) by inter-vehicle communication.
The follow-up control unit 12 includes a front-rear direction front-rear control unit and a left-right direction left-right control unit based on feedback control and feedforward control.
The follow-up control unit 12 is a front-rear control command value (target speed or target acceleration) by the front-rear control unit based on each input from the preceding vehicle relative position detection unit 11, the vehicle speed sensor 30, the yaw rate sensor 40, and the wireless communication device 50. And a left / right control command value (target rotational angular velocity ω) by the left / right control unit is supplied to the vehicle control unit 13.

The vehicle control unit 13 controls the drive motors 60a and 60b.
That is, the vehicle control unit 13 controls the drive motors 60a and 60b so that the target speed (or target acceleration) supplied from the follow-up control unit 12 is achieved. Specifically, the vehicle control unit 13 includes a speed (or acceleration) -current map for the drive motor 60, and a target speed (or target acceleration) supplied from the follow-up control unit 12 according to the torque-current map. The current control is performed so that the current corresponding to () is output to the drive motor 60.

  In addition, the vehicle control unit 13 outputs different currents to the drive motors 60a and 60b so that the tracking vehicle 3 turns at the target rotational angular velocity ω (left and right control command value) supplied from the tracking control unit 12. Thus, the turning may be performed by the differential between the drive motors 60a and 60b.

  In this embodiment, the inverted pendulum vehicle is described as an object. However, the present invention can also be applied to other vehicles such as a four-wheel vehicle, and in this case, the vehicle includes a steering motor. And the vehicle control part 13 controls a steering motor so that it may become a steering angle corresponding to the target rotational angular velocity (omega) supplied from the tracking control part 12. FIG.

Next, the control performed by the following vehicle 3 when the following vehicle 3 travels in parallel with the preceding vehicle 2 will be described.
The control performed when the following vehicle 3 travels in parallel running follows the control performed by the following vehicle 3 in the front-rear direction (vehicle speed direction, vertical direction) of the host vehicle, and the left-right direction of the host vehicle (direction perpendicular to the vehicle speed, There is control to be performed in the horizontal direction.
Further, the control performed in the front-rear direction may be further controlled at the target speed or at the target acceleration, and which one is adopted depends on the design of the following vehicle 3.
Therefore, in the present embodiment, the control in which the following vehicle 3 travels in parallel with the preceding vehicle 2 is performed in the front-rear direction using the target speed, or in the left-right direction when performed in the front-rear direction using the target acceleration. Three cases will be described.

The relationship between the preceding vehicle 2 and the following vehicle 3 is the same as that of the conventional example of FIG. 10, and the following vehicle 3 is located in the left-right direction (the side where the following vehicle 3 follows in parallel) from the representative point 6 of the preceding vehicle 2. It is assumed that a target point 5 is set at the position, and a left-right deviation Δw in the left-right direction and a front-rear deviation Δd in the front-rear direction occur between the representative point 7 of the following vehicle 3 and the target point 5.
These Δw and Δd indicate that the following vehicle 3 measures the position of the preceding vehicle 2 with the laser radar 20 (FIG. 1), or that the preceding vehicle 2 transmits the current position of the preceding vehicle 2 by wireless communication. Can be obtained.

[Control performed in the longitudinal direction using the target speed]
The basic concept of this control will be described with reference to FIG.
The following vehicle 3 travels in parallel following the left side of the preceding vehicle 2, and the preceding vehicle 2 has a turning angular velocity (target angular acceleration) ω around the turning center C at a distance r from the representative point 6. Consider the case of turning right.
The following vehicle 3 performs feedback control so that the target point 5 (overlapping with the representative point 7 in the figure) determined based on the representative point 6 of the preceding vehicle 2 coincides with the representative point 7 of the own vehicle, and enhances the response. For this reason, the target speed is transmitted from the preceding vehicle 2, and the feedforward control is also performed so that the host vehicle becomes the target speed.
Thus, the following vehicle 3 includes target point acquisition means for acquiring the target point 5 for following the preceding vehicle 2.

By the way, when the preceding vehicle 2 is traveling straight, the vehicle speeds of the preceding vehicle 2 and the following vehicle 3 are the same, and thus the feedforward control is sufficient. However, when the preceding vehicle 2 turns, the following vehicle 3 becomes the preceding vehicle. 2, the vehicle speed of the following vehicle 3 needs to be faster than the preceding vehicle 2, and the vehicle speed of the following vehicle 3 needs to be slower than the preceding vehicle 2 when traveling along the inner periphery. There is.
Therefore, the preceding vehicle 2 calculates the increase / decrease in the vehicle speed accompanying the turn, adjusts this to the target speed sent from the preceding vehicle 2, and uses this for feedforward control.

In the case of FIG. 2, the vehicle speed (front-rear direction speed) v1 of the preceding vehicle 2 is rω.
Assuming that the distance between the representative points 6 and 7 is the actual inter-vehicle distance aR, when the following vehicle 3 travels along the outer periphery of the preceding vehicle 2, the vehicle speed (velocity in the front-rear direction) v2 of the following vehicle 3 is (r + aR). ) Ω.
For this reason, the following vehicle 3 needs to travel faster than the preceding vehicle 2 by (r + aR) ω−rω = aRω, and the following vehicle 3 adds aRω to the target speed transmitted from the preceding vehicle 2. The value is the target speed of the host vehicle.

On the other hand, when the following vehicle 3 runs in parallel on the inner peripheral side of the preceding vehicle 2, a value obtained by subtracting aRω from the target speed transmitted from the preceding vehicle 2 is set as the target speed of the host vehicle.
In this way, when the following vehicle 3 makes parallel running following the preceding vehicle 2, the excess or deficiency of the target speed caused by the turn of the preceding vehicle 2 is corrected, and feedforward control is performed with the corrected value. be able to.

FIG. 3A is a functional block diagram of the front-rear direction control processing unit 70 that performs the above-described control.
The front-rear direction control processing unit 70 includes a feedback processing unit 72 that performs feedback control and a feedforward processing unit 71 that performs feedforward control.
Note that these functional units are configured, for example, when a CPU (Central Processing Unit) of the ECU 10 executes a program for control processing.

The feedback processing unit 72 is a processing unit that performs feedback control so that the front-rear deviation Δd converges to 0. When the front-rear deviation Δd is input, the feedback processing unit 72 multiplies the front-rear deviation Δd by the proportional coefficient kp1 and time-differentiates the front-rear deviation Δd. ("S" in the figure) This is multiplied by a proportional coefficient kd1, and these are added and output.
As a result, the follower vehicle 3 increases the vehicle speed and converges Δd to 0 as Δd increases (gain is kp1) and as Δd increases (gain is kd1).

The process performed by the feedback processing unit 72 is a technique for keeping the distance in the front-rear direction constant, as in the feedback process performed by the conventional technique, and is generally the same control as that performed by the adaptive auto-cruise device.
As described above, the feedback processing unit 72 functions as a feedback unit that performs feedback control on the deviation from the target point 5.

The front-rear direction control processing unit 70 includes a feedforward processing unit 71 in addition to the conventional feedback processing unit 72. This is due to the following background.
Feedback control can be controlled strictly when the delay from the signal input to the onset of action, such as the delay or dead time of the controlled object, can be strictly controlled, but in the case of a large delay like an automobile, Operation overshoot or hunting may occur.
For this reason, the feedback control is not suitable for strictly maintaining the inter-vehicle distance in the following traveling of the vehicle. For example, the inter-vehicle distance is several tens of meters while traveling at high speed on the expressway. Used when distance is not maintained.
Therefore, the follow-up vehicle 3 is provided with a feedforward processing unit 71 in the front-rear direction control processing unit 70 in order to increase the responsiveness of the follow-up control.

First, the front-rear direction command value uLFB (in this case, the target speed of the preceding vehicle 2 for control at the target speed) wirelessly transmitted from the preceding vehicle 2 is input to the feedforward processing unit 71.
Here, the front-rear direction command value uLFB functions as vehicle speed control information for controlling the vehicle speed of the preceding vehicle 2. For this reason, the following vehicle 3 includes vehicle speed control information acquisition means.

Further, the actual inter-vehicle distance aR and the left-right direction command value uLLR are input to the feedforward processing unit 71. The actual inter-vehicle distance aR and the left-right direction command value uLLR are calculated by the vehicle speed increase / decrease function fvt, and the calculated values are added to the front-rear direction command value uLFB.
The actual inter-vehicle distance aR is the distance between the representative points 6 and 7 and can be obtained by measurement with the laser radar 20 or communication with the preceding vehicle 2. Thus, the following vehicle 3 includes a distance acquisition unit that acquires a distance from the preceding vehicle 2.

Further, the left-right direction command value uLLR is received from the preceding vehicle 2, and is information that can specify at least the target angular velocity ω of the preceding vehicle 2, such as information related to turning of the preceding vehicle 2, for example, the steering amount. .
The target angular velocity ω of the preceding vehicle 2 can be obtained from the left-right direction command value uLLR. For this reason, the following vehicle 3 includes angular velocity acquisition means for acquiring the angular velocity of the turn performed by the preceding vehicle.
The vehicle speed increase / decrease function fvt is fvt = aRω when the follower vehicle 3 runs on the outer periphery of the preceding vehicle 2, and fvt = −aRω when the follower vehicle 3 runs on the inner periphery.

  As described above, when the follower vehicle 3 runs around the outer periphery of the preceding vehicle 2, the feedforward processing unit 71 adds aRω to the target speed (front-rear direction command value uLFB) of the preceding vehicle 2 to When the target speed is corrected and the vehicle travels on the inner circumference, the target speed of the preceding vehicle 2 is corrected by subtracting aRω from the target speed of the preceding vehicle 2, and a vehicle speed at which the following vehicle 3 can turn with the preceding vehicle 2 is output. To do.

In this way, the feedforward processing unit 71 increases or decreases the vehicle speed (aRω) necessary for turning the control amount specified by the vehicle speed control information (front-rear direction command value uLFB) while running in parallel with the preceding vehicle 2. And a feedforward means for performing feedforward control using a control amount (vehicle speed information) corrected by the correction means.
Further, the following vehicle 3 includes a determination unit that determines whether the host vehicle travels on the inner periphery or the outer periphery when the preceding vehicle 2 turns, and the correction unit is configured to determine the distance (actual inter-vehicle distance aR). And the angular velocity (target angular velocity ω) is acquired, and when the determination means determines that the vehicle travels on the outer periphery, the control amount is increased by the correction amount, and when the determination device determines that the vehicle travels on the inner periphery. Reduces the control amount by the correction amount.

As described above, after the processing by the feedback processing unit 72 and the processing by the feedforward processing unit 71 are performed, the front-rear direction control processing unit 70 adds the outputs of the feedback processing unit 72 and the feedforward processing unit 71 and performs the front-rear direction command. The following vehicle 3 increases or decreases the vehicle speed based on the front-rear direction command value uFB.
In this way, the follower vehicle 3 performs feedback control for converging the deviation d to 0 and feedforward control that travels at the corrected target speed of the preceding vehicle 2 in parallel to realize followability by feedback control. Insufficient responsiveness of feedback control can be supplemented by feedforward control.

If there is no correction by the vehicle speed increase / decrease function fvt and the feedforward control is performed only by the front / rear direction command value uLFB, the following is obtained.
It is assumed that the preceding vehicle 2 is turning and the following vehicle 3 is traveling on the outer periphery of the preceding vehicle 2.
In this case, the following vehicle 3 lags behind the target point 5 because the vehicle speed of the following vehicle 3 is insufficient at the target vehicle speed based on the longitudinal direction command value uLFB transmitted from the preceding vehicle 2 to the following vehicle 3.

Then, the following vehicle 3 mainly performs feedback control in order to complement the decrease in response of the feedforward control, and the effect of the feedforward control cannot be obtained.
In particular, when the speed of the preceding vehicle 2 and the following vehicle 3 are greatly different, for example, at the start of turning or at the end of turning, such a tendency becomes remarkable.

Thus, if there is no correction by the vehicle speed increase / decrease function fvt, feedback control is almost performed during turning, and it is difficult to strictly adjust the inter-vehicle distance due to the low response of feedback control.
Therefore, when the feedforward processing unit 71 corrects the left-right direction command value uLLR using the vehicle speed increase / decrease function fvt, the feedforward control can be effectively applied even during a turn.

As described above, the following vehicle 3 follows the preceding vehicle 2 sideways, and when the vehicle is controlled at the target speed, the front-rear direction control processing unit 70 responds to the turning radius and the turning speed of the preceding vehicle 2. Thus, the speed to be added (preceding vehicle 2 is inside) or decreased (preceding vehicle 2 is outside) is calculated, and the feedforward control is performed together with the preceding vehicle control amount (speed target value) obtained from the preceding vehicle 2 through communication. .
Further, the follow-up vehicle 3 can simultaneously perform feedback control for the vertical deviation by the feedback processing unit 72 and can be integrated as a control amount.

[Control performed in the longitudinal direction using the target acceleration]
FIG. 3B is a functional block diagram of the front-rear direction control processing unit 73, which performs front-rear direction control using the target acceleration.
The front-rear direction control processing unit 73 is obtained by replacing the feedforward processing unit 71 of the front-rear direction control processing unit 70 with a feedforward processing unit 74, and the configuration of the feedback processing unit 72 is the same as that of the front-rear direction control processing unit 70. .

Since the front-rear direction control processing unit 73 performs control based on the target acceleration, the front-rear direction command value uLFB input to the feedforward processing unit 74 is, for example, the preceding vehicle 2 such as accelerator opening information and brake information of the preceding vehicle 2. It becomes the information showing the target acceleration.
Thus, in this example, the target acceleration functions as vehicle speed control information.

The actual inter-vehicle distance aR, the left-right direction command value uLLR, and the vehicle speed increase / decrease function fvt input to the feedforward processing unit 74 are the same as those of the feedforward processing unit 71.
The feedforward processing unit 74 differentiates the output of the vehicle speed increase / decrease function fvt with respect to time (“s” in the figure).

From the vehicle speed increase / decrease function fvt, the vehicle speed increase / decrease is output every moment, and by differentiating this with time, the rate of change of the vehicle speed increase / decrease, that is, the acceleration is obtained.
By the way, when the output of the vehicle speed increase / decrease function fvt is differentiated, for example, when the left-right direction command value uLLR changes abruptly, the differentiated value may become an impulse shape.
As described above, when the signal becomes an impulse shape by the differential operation, the following vehicle 3 cannot follow in response to this, so the first-order lag operation is performed by “1 / (1 + Ts)” in the figure, and the signal The rapid change is alleviated (smoothed), and this is added to the front-rear direction command value uLFB.

Here, the time constant T is an appropriate constant determined in consideration of the response of the following vehicle 3 and the like.
Thus, the front-rear direction control processing unit 73 can generate the front-rear direction command value uFB by acceleration, and the following vehicle 3 controls the vehicle speed using the front-rear direction command value uFB as the target acceleration.
Thus, in this example, the vehicle speed control information sent from the preceding vehicle 2 is the acceleration information (target acceleration) of the preceding vehicle 2, and the correction means uses the distance (aR) and the angular velocity (left-right direction command value uLLR). The tracking vehicle 3 is provided with mitigation means (first-order lag term) for mitigating sudden changes in the correction amount due to the differentiation.

By the way, the background of configuring the system using the target acceleration in this way will be described.
When actual control is considered, it is easy to realize a control target using a target acceleration. For example, an accelerator of a car adjusts acceleration, and in the case of an electric car, a motor is often configured to control output torque.
For this reason, it is desirable that the control output is also an acceleration command value. However, since the target speed is calculated by fvt, it is necessary to convert this into acceleration. Thus, the front-rear direction control processing unit 73 differentiates this value.

However, since the calculation result often rises in an impulse manner only with differentiation, and there is a case where the response of the control target cannot follow, the front-rear direction control processing unit 73 controls the differential value by applying a first-order delay. It is adapted to the responsiveness of the subject.
The time constant T of the first-order delay is determined in consideration of vehicle responsiveness. For example, when the physical model in the front-rear direction of the control target (vehicle) can be approximated as a first-order lag, a value equal to or greater than the time constant Tv is set (T> Tv). If the dead time Tf is also included, this is also added and set to a value greater than that (T> Tv + Tf). When the physical model is expressed by a second-order or higher-order delay, the criterion is applied by approximating the first-order delay.

As described above, the front-rear direction control processing unit 73 follows the preceding vehicle 2 laterally, and further, when the vehicle is controlled at the target acceleration, the following vehicle 3 responds to the turning radius and the turning speed of the preceding vehicle 2. Then, the speed at which addition (preceding vehicle 2 is inside) or reduction (preceding vehicle 2 is outside) is calculated and differentiated to obtain the preceding vehicle control amount (acceleration target value) obtained from the preceding vehicle 2 by communication or the like. At the same time, feedforward control is performed.
Then, a command value that can be responded to by the host vehicle is applied to the command value by applying a first-order lag operation in consideration of the response of the host vehicle to the command value that has become an impulse shape by the differential operation.
Further, the follow-up vehicle 3 simultaneously performs feedback control on the vertical deviation by the feedback processing unit 72 and integrates it as a control amount.

[Control performed in the horizontal direction]
FIG. 4 is a diagram for explaining a basic concept of control performed in the left-right direction.
The representative point 7 of the following vehicle 3 is displaced from the target point 5 by the front-rear deviation Δd and the left-right deviation Δw. The angle formed by the following vehicle 3 and the target point 5 is the azimuth angle φ, and the preceding vehicle 2 and the following vehicle 3 are traveling. The angle formed by the direction (the difference between the directions of the preceding vehicle 2 and the following vehicle 3) is defined as a relative angle θ.

In a nonholonomic system such as a vehicle, it is difficult to simultaneously realize the convergence of the relative angle θ and the convergence to the target point 5, and there is no solution.
Therefore, in the present embodiment, a configuration is adopted in which one of the more urgent parameters that may cause a collision if left unattended is converged first.
For this reason, the following vehicle 3 sets the final turning angle (corresponding to the control target angle to be converged) using the azimuth angle φ and the relative angle θ, and converges the final turning angle so that the convergence is achieved.

More specifically, the final turning angle is calculated by calculating the azimuth angle φ and the relative angle θ as a function. In this calculation, the azimuth angle using the target point distance Δm between the representative point 7 and the target point 5 as a parameter. Weight the contribution of φ.
Thereby, when the preceding vehicle 2 and the following vehicle 3 are close to each other (when the target point distance Δm is small), if the azimuth angle φ is changed suddenly, the preceding vehicle 2 and the following vehicle 3 may come into contact with each other. Therefore, the azimuth angle φ is changed little by little (gain is reduced), and when the target point distance Δm is large, there is no possibility of contact, so the azimuth angle φ is greatly changed (gain is increased).
Further, as the target point distance Δm increases, the output (change in azimuth angle φ) may become too large when the gain is increased. Therefore, as shown in FIG. 5, the target point distance Δm is a predetermined value. In the case of k or more, an upper limit is set on the output so that the output is constant.
Thus, an upper limit is set for the degree of contribution of the azimuth angle φ to the final turning angle (control target angle).

FIG. 6 is a functional block diagram of the left-right direction control processing unit 75 that performs left-right control.
A target point distance Δm, an azimuth angle φ, and a relative angle θ are input to the left / right direction control processing unit 75 and used for feedback control, and the left / right direction command value uLLR is used for feedforward control.
Thus, the following vehicle 3 has an azimuth angle obtaining unit that obtains an azimuth angle φ from the own vehicle to the target point 5 and a relative angle obtaining unit that obtains a relative angle θ formed by the traveling direction of the own vehicle and the preceding vehicle 2. And target point distance acquisition means for acquiring a target point distance Δm from the host vehicle to the target point 5.

The left-right direction control processing unit 75 multiplies the target point distance Δm by a proportional constant kL1 and further multiplies this by an azimuth angle φ to calculate a first target turning angle ψ.
Then, the left-right direction control processing unit 75 causes the function fst to act on the first target turning angle ψ and the relative angle θ, and multiplies the final turning angle output as a result by a constant kA1 to generate a signal for feedback control.

Here, the function fst checks the signs of the azimuth angle φ and the first target turning angle ψ, and if the signs are different, outputs the sum of φ and ψ as the final turning angle. The one with the larger value is output as the final turning angle.
That is, the function fst outputs θ + ψ if sgn (θ) ≠ sgn (ψ), and outputs θ if sgn (θ) = sgn (ψ) and | θ | ≧ | ψ |. If sgn (θ) = sgn (ψ) and | θ | <| ψ |, ψ is output.
The final turning angle output here functions as a control target angle obtained by using the azimuth angle φ and the relative angle θ, and the following vehicle 3 includes control target angle acquisition means for acquiring the control target angle. And feedback means for performing feedback control so as to converge the final turning angle.

Further, the left-right direction control processing unit 75 performs feed-forward control by adding the left-right direction command value uLLR to the feedback control signal, and obtains the left-right direction command value uLR subjected to both feedback control and feed-forward control. Output.
The left-right direction command value uLR is used as a turning angular velocity command, a steering wheel steering angle command, and the like, and the following vehicle 3 controls turning according to the left-right direction command value uLR.
Thus, the follower vehicle 3 uses the turn control information acquisition means for acquiring the turn control information (left-right direction command value uLLR) for controlling the turn from the preceding vehicle 2, and uses the turn control information as a control target angle. A turning feedforward means for performing feedforward control is provided.

The left-right direction control processing unit 75 processes the signal as described above, and the meaning thereof is as follows.
First, the left-right direction control processing unit 75 calculates the first target turning angle ψ by multiplying the target point distance Δm by kL1 and multiplying by the azimuth angle φ. The first target turning angle ψ is a relative angle. In order to compare the relative priority of the azimuth angle φ with respect to θ, the azimuth angle φ is an amount weighted by the target point distance Δm.

Thus, since the first target turning angle ψ multiplies the azimuth angle φ by the target point distance Δm, the priority of the azimuth angle φ depends on the target point distance Δm. The factor to be expressed (factor determining the degree of urgency) is kL1.
That is, the smaller the target point distance Δm (the closer the preceding vehicle 2 and the following vehicle 3), the smaller the first target turning angle ψ and the lower the priority of the azimuth angle φ, while the larger the target point distance Δm. As the first target turning angle ψ increases, the priority of the azimuth angle φ increases, and kL1 relatively determines the priority of the azimuth angle φ with respect to the relative angle θ.
Thus, the greater the target point distance Δm, the higher the priority of the azimuth angle φ and the greater the contribution to the final turning angle (control target angle).

The value of kL1 can be defined as follows, for example.
An amount of deviation from the target point 5 that can be allowed when the following vehicle 3 is controlled is set in advance, and is set to output 1 when this value is Δp. For example, a deviation amount Δ that can tolerate 0.3 m
In the case of p, kL1 = 3.3 from 0.3 kL1 = 1.

In the above description, kL1 is expressed as a multiplication term, but may be expressed as a function.
In the case of a function, for example, the function is as shown in FIG. 5, which is based on the above 3.3 and restricts the output when Δp is large. This can prevent the behavior from becoming unstable when Δp may become extremely large.
K that does not cause the behavior to become unstable can be determined experimentally.

The function fst evaluates the priority of the azimuth angle φ and the relative angle θ, and uses this to output the final turning angle.
Here, the function fst uses the first target turning angle ψ for the comparison of the azimuth angle φ, and compares the azimuth angle φ (that is, ψ) with the target point distance Δm and the relative angle θ.
As a result, when it is far from the target point 5, the influence of the azimuth angle φ is increased (the first target turning angle ψ is output large), and the convergence to the target point 5 is preferentially performed. .

When the target point 5 is substantially satisfied, the influence degree of the azimuth angle φ becomes small (the first target turning angle ψ is outputted small), and the relative angle θ is preferentially set to zero.
The function fst compares the relatively adjusted first target turning angle ψ and the relative angle θ with the sign and the value, and finally makes a determination to determine the output.

  kA1 is a feedback proportional constant of the control system, and is a feedback gain for realizing the adopted angle (final target angle output by the function fst). Further, a differential constant or an integral constant may be added to kA1.

By the way, as conventional control in the left-right direction, for example, there is one used as a lane keeping device.
This is a device that recognizes a white line and controls it so that it stays in the lane, but this is also a device that is mainly used on a road with a small curvature (a large turning radius) such as an expressway. It does not support sudden turns.

Further, in order to improve control responsiveness in the control in the left-right direction, it is also possible to acquire turning information such as a steering angle from the preceding vehicle 2 and perform feedforward control using this.
However, the feedforward control functions effectively when the directions of the preceding vehicle 2 and the following vehicle 3 are hardly changed. However, as the difference in direction increases, not only the effect of the following control decreases, There is also a possibility that the following vehicle 3 comes into contact.

  In the conventional technology, there is a problem in the responsiveness and the control accuracy of the inter-vehicle distance when maintaining the inter-vehicle distance of several meters and considering the use for a vehicle that runs side by side in the vertical or horizontal direction. there is a possibility. Even if the control constant is selected strictly, it becomes an apparatus that can be used only in a limited case such as a specific speed or turning radius, and is not practical.

  Therefore, the left-right direction control processing unit 75 determines the priority of the azimuth angle φ and the relative angle θ, performs fine control by these two angles, and the preceding vehicle 2 and the following vehicle 3 are close to each other. In such a case, the possibility that the preceding vehicle 2 and the following vehicle 3 come into contact with each other is reduced by, for example, reducing the gain when controlling the azimuth angle φ.

In this way, the left-right direction control processing unit 75 uses the azimuth angle φ from the follower vehicle 3 to the target point 5 and the relative angle θ that is the difference between the directions of the preceding vehicle 2 and the follower vehicle 3 to determine the final turning angle. Is calculated as a target relative angle, and feedback control is performed on this.
The left-right direction control processing unit 75 multiplies the azimuth angle φ by a gain kL1 corresponding to the target point distance Δm to the target point 5 to reduce an excessive reaction near the target point 5.
Further, the left / right direction control processing unit 75 is based on a left / right direction command value uLLR (preceding vehicle control amount, more specifically, a turning angular velocity target value or a turning radius target value) obtained from the preceding vehicle 2 through communication or the like. In addition, feed-forward control is performed at the same time and integrated as a controlled variable.

FIG. 7 is a flowchart for explaining a follow-up control procedure during parallel follow-up running performed by the ECU 10.
The following processing is performed by the CPU of the ECU 10 according to a predetermined program.
First, the following vehicle 3 calculates the position of the target point 5 from the current position of the preceding vehicle 2 (step 5).
Next, the following vehicle 3 calculates the front / rear direction command value uFB (step 10), and further calculates the left / right direction command value uLR (step 15).
Then, the following vehicle 3 performs front-rear direction control using the front-rear direction command value uFB, and performs left-right direction control using the left-right direction command value uLR (step 17).
Thereafter, the ECU 10 repeats steps 5-17.

FIG. 8 is a flowchart for explaining the procedure of the longitudinal direction command value calculation process performed by the longitudinal direction control processing unit 70.
First, the following vehicle 3 detects an actual inter-vehicle distance aR with the preceding vehicle 2 (step 20).
Next, the following vehicle 3 receives the left-right direction command value uLLR from the preceding vehicle 2 by communication or the like (step 25).

Next, the following vehicle 3 grasps the positional relationship with the preceding vehicle 2 (step 30). That is, the following vehicle 3 recognizes the preceding vehicle 2 by using the laser radar 20 or the like, and grasps which side of the preceding vehicle 2 is running in parallel.
The following vehicle 3 can determine whether the own vehicle is on the outer peripheral side or the inner peripheral side from the position of the own vehicle and the turning direction obtained from the left-right direction command value uLLR.

Next, the following vehicle 3 calculates the target angular velocity ω from the left-right direction command value uLLR (step 35), and inputs the actual inter-vehicle distance aR and the target angular velocity ω to the vehicle speed increase / decrease function fvt to increase or decrease the speed relative to the preceding vehicle 2. Is calculated (step 40).
Further, the following vehicle 3 acquires the front-rear direction command value uLFB received from the preceding vehicle 2 (step 45).

Then, the following vehicle 3 calculates the front-rear deviation Δd (step 50), and adds the feedback control signal based on the output of the vehicle speed increase / decrease function fvt, the front-rear direction command value uLFB, and the front-rear deviation Δd to calculate the front-rear direction command value uFB. (Step 55).
The processing performed by the front-rear direction control processing unit 70 has been described above, but the processing performed by the front-rear direction control processing unit 73 is the same.

FIG. 9 is a flowchart for explaining the procedure of the horizontal direction command value calculation process.
First, the following vehicle 3 calculates the target point distance Δm (step 60), and further calculates the azimuth angle φ (step 65).
Next, the following vehicle 3 multiplies the target point distance Δm by kL1 as a gain (step 70), and further multiplies this by the azimuth angle φ to calculate the first target turning angle ψ (step 75).

Next, the following vehicle 3 calculates a relative angle θ with respect to the preceding vehicle 2 (step 80), and performs determination using the function fst (step 85).
If the sign of the first target turning angle ψ and the relative angle θ is different for the following vehicle 3 (step 85; Y), the following vehicle 3 sets θ + ψ as the final turning angle (step 95).
On the other hand, when the signs of the first target turning angle ψ and the relative angle θ are the same (step 85; N), the following vehicle 3 compares the absolute value of the relative angle θ and the absolute value of the first target turning angle ψ (step). 90).

  As a result of the comparison, when the absolute value of the relative angle θ is smaller than the first target turning angle ψ (step 90; Y), the following vehicle 3 sets the first target turning angle ψ as the final turning angle (step 100). When the absolute value of the relative angle θ is equal to or greater than the first target turning angle ψ (step 90; N), the follower vehicle 3 sets the relative angle θ as the final turning angle (step 105).

  After determining the final turning angle in this way, the follower vehicle 3 acquires the left-right direction command value uLLR (step 110), adds the value obtained by multiplying the final turning angle by kA1 and the left-right direction command value uLLR, The direction command value uLR is output (step 115).

According to the embodiment described above, the following effects can be obtained.
(1) When the following vehicle 3 travels in parallel with the preceding vehicle 2, for the control in the front-rear direction, in addition to the feedback control, feed-forward control based on the front-rear direction command value uLFB from the preceding vehicle 2 is performed. be able to.
In this feedforward control, the increase / decrease of the vehicle speed of the following vehicle 3 required when the preceding vehicle 2 turns can be calculated and used to correct the front-rear direction command value uLFB.
(2) Since feedforward control is performed based on the corrected information, the deviation from the target point 5 is small even during turning, and feedforward control can be effectively maintained.
(3) When feedforward control is performed using the target acceleration, the impulse of the feedforward signal is generated by applying a first-order lag term to the derivative of increase / decrease in vehicle speed of the following vehicle 3 required when the preceding vehicle 2 turns. Can be suppressed.
(4) The following vehicle 3 can determine the final turning angle by using the azimuth angle φ and the relative angle θ for the control in the front-rear direction when the vehicle follows the parallel running following the preceding vehicle 2.
(5) The gain for converging the azimuth angle φ can be changed by the target point distance Δm, and when the preceding vehicle 2 and the following vehicle 3 are approaching, the azimuth angle φ changes suddenly and both vehicles Can be prevented from touching.
(6) When the preceding vehicle 2 and the following vehicle 3 are separated from each other by a predetermined distance or more, the gain for converging the azimuth angle φ is constant, and a sudden change in the azimuth angle φ is suppressed.
(7) In a non-holonomic vehicle, a system that performs group traveling by following the vehicle in the front-rear direction or the left-right direction, and maintaining stability of the front-rear direction control and the left-right direction control simultaneously. it can.

In addition, the present embodiment can provide the following configuration.
A vehicle that performs parallel running following with respect to a preceding vehicle, and acquires a target point acquisition means for acquiring a target point for following the preceding vehicle, and acquires an azimuth angle from the own vehicle to the acquired target point. Azimuth angle acquisition means, relative angle acquisition means for acquiring a relative angle formed by the traveling direction of the host vehicle and the preceding vehicle, and control target angle acquisition means for acquiring a control target angle using the acquired azimuth angle and relative angle And a feedback means for performing feedback control so that the acquired control target angle converges (first configuration).
A target point distance acquisition unit that acquires a target point distance from the host vehicle to the acquired target point is provided, and the control target angle acquisition unit increases the acquired azimuth angle as the acquired target point distance increases. A vehicle having a first configuration (second configuration) characterized in that the degree of contribution to a control target angle is increased.
A vehicle having a second configuration (third configuration), wherein an upper limit is provided for the degree of contribution of the azimuth angle to the control target angle.
Turning control information acquisition means for acquiring turning control information for controlling turning from the preceding vehicle; turning feedforward means for performing feedforward control on the control target angle using the acquired turning control information; A vehicle having a first configuration, a second configuration, or a third configuration (fourth configuration).

It is the figure which showed the structure of the following vehicle. It is a figure for demonstrating the basic concept of the control of the front-back direction which a tracking vehicle performs. It is a functional block diagram of a front-back direction control processing unit. It is a figure for demonstrating the basic concept of the control of the left-right direction which a tracking vehicle performs. It is a figure for demonstrating the upper limit of the contribution degree of azimuth angle (phi). It is a functional block diagram of a left-right direction control processing unit. It is a flowchart for demonstrating the tracking control procedure at the time of parallel tracking driving | running | working. It is a flowchart for demonstrating the procedure of a front-back direction command value calculation process. It is a flowchart for demonstrating the procedure of the left-right direction command value calculation process. It is a figure for demonstrating a prior art example.

Explanation of symbols

2 preceding vehicle 3 following vehicle 5 target point 6 representative point 7 representative point 10 ECU
DESCRIPTION OF SYMBOLS 11 Leading vehicle relative position detection part 12 Following control part 13 Vehicle control part 20 Laser radar 30 Vehicle speed sensor 40 Yaw rate sensor 50 Wireless communication apparatus 60a, 60b Drive motor 70 Front-rear direction control processing part 71 Feed forward processing part 72 Feedback processing part 73 Front and rear Direction control processing unit 74 Feed forward processing unit 75 Left / right direction control processing unit

Claims (7)

A vehicle that performs parallel running following the preceding vehicle,
Target point acquisition means for acquiring a target point for following the preceding vehicle;
Feedback means for performing feedback control on the deviation from the acquired target point;
Vehicle speed control information acquisition means for acquiring vehicle speed control information for controlling the vehicle speed of the preceding vehicle;
Correction means for correcting the control amount defined by the acquired vehicle speed control information using an increase / decrease amount of the vehicle speed required when turning while parallel to the preceding vehicle,
Feedforward means for performing feedforward control using the control amount after correction by the correction means;
A vehicle characterized by comprising: Distance acquisition means for acquiring a distance from the preceding vehicle;
Angular velocity acquisition means for acquiring the angular velocity of the turn performed by the preceding vehicle;
Determining means for determining whether the host vehicle travels on an inner periphery or an outer periphery when the preceding vehicle turns;
Comprising
The correction means acquires a correction amount using the acquired distance and angular velocity, and when the determination means determines to travel on the outer periphery, the control amount is increased by the correction amount, and the determination means The vehicle according to claim 1, wherein when it is determined that the vehicle travels around the circumference, the control amount is decreased by the correction amount. The vehicle speed control information is acceleration information of the preceding vehicle,
The correction means obtains a correction amount by differentiating the product of the acquired distance and angular velocity,
The vehicle according to claim 2, further comprising a mitigating means for mitigating a sudden change in the correction amount due to the differentiation. Azimuth angle obtaining means for obtaining an azimuth angle from the host vehicle to the acquired target point;
A relative angle acquisition means for acquiring a relative angle formed by the traveling direction of the host vehicle and the preceding vehicle;
Control target angle acquisition means for acquiring a control target angle using the acquired azimuth angle and relative angle;
Comprising
The vehicle according to any one of claims 1, 2, and 3, wherein the feedback unit performs feedback control so that the acquired control target angle converges. Comprising target point distance acquisition means for acquiring a target point distance from the host vehicle to the acquired target point;
The vehicle according to claim 4, wherein the control target angle acquisition unit increases the degree of contribution of the acquired azimuth angle to the control target angle as the acquired target point distance increases.   The vehicle according to claim 5, wherein an upper limit is provided for a degree of contribution of the azimuth angle to the control target angle. Turning control information acquisition means for acquiring turning control information for controlling turning from the preceding vehicle;
Turning feedforward means for performing feedforward control on the angle to be controlled using the obtained turning control information;
The vehicle according to claim 4, claim 5, or claim 6.

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