JP5100426B2 - Follow-up control device - Google Patents

Description

  The present invention relates to a vehicle follow-up travel control device, and more particularly to improvement in travel performance immediately after a preceding vehicle starts and starts follow-up travel control.

  Conventionally, this type of travel control device performs known follow-up travel control of feedback control (hereinafter referred to as FB control) so that the preceding vehicle and the host vehicle maintain a constant distance (including the distance between the vehicles).

  In the following running control of the FB control, a necessary acceleration / deceleration control amount is calculated according to a control target value based on the distance and relative speed between the preceding vehicle and the own vehicle, and the following of the own vehicle is calculated based on the calculated control amount. Travel is controlled.

  In this case, the distance between the preceding vehicle and the host vehicle is particularly short, and the change in the distance due to acceleration / deceleration of the preceding vehicle (and thus the change in relative speed) is large. It is likely to be an unstable follow-up run that is “jerky”. It should be noted that the acceleration response to the engine output is highly non-linear until starting from the stop state, and acceleration / deceleration control is difficult.

  Therefore, it has been proposed that the acceleration control immediately after the start operation is feed forward control (hereinafter referred to as FF control) to improve the acceleration feeling at the start (for example, refer to Patent Document 1). Note that the FF control in this case is performed based on data that is preset and held as map data or the like.

  In addition, when starting from a state in which the distance between the preceding vehicle and the host vehicle is short and following the vehicle, follow-up driving control that incorporates FF control is added to the FB control when starting to reduce the feeling of stickiness in the FB control. It has been proposed to do so (see, for example, Patent Document 2). The FF control in this case is control based on a predetermined target value set in advance, and the influence on the control of the follow-up running is the speed of the preceding vehicle (or the passage of time) at a predetermined speed or less (or within a predetermined time). The control changes in inverse proportion, and is executed only when the inter-vehicle distance is equal to or greater than the set safety distance.

JP 2004-232570 A (Abstract, paragraphs [0013]-[00019], [0029]-[0049], FIG. 1 and the like) Japanese Patent Laid-Open No. 11-66499 (claims, paragraphs [0026]-[0034], [0043]-[0048], [0120]-[0128], FIG. 2, FIG. 14, etc.)

  In the follow-up running control described in Patent Document 1, the behavior (acceleration / deceleration) of the preceding vehicle at the start, the distance between the preceding vehicle before the start and the own vehicle, etc. are variously different and indefinite and unstable. On the other hand, since the FF control at the start is performed based on preset data such as map data, smooth and smooth follow-up control at the start cannot be performed depending on the behavior of the preceding vehicle. There's a problem.

  In the case of the follow-up running control described in Patent Document 2, since the FB control is added to the FB control and the FB control is the main control, there is a problem described below.

  First, when the own vehicle starts following the preceding vehicle, the control at the time of starting requires control different from the FB control during traveling for the following reasons (1) to (6).

  (1) At the time of start, it is necessary to generate before starting the torque to start from the own vehicle stop state to the running state. (2) The preceding vehicle will always start first, and the vehicle will start following after that. (3) During an extremely low speed state of about 2 or 3 seconds immediately after starting, the fluctuation of the driving torque with respect to the acceleration / deceleration change is large, and the acceleration / deceleration sensitivity of the torque is high. Moreover, the torque response to acceleration / deceleration changes is highly nonlinear. (4) When starting, the influence of running resistance such as a slope road is large. (5) The accuracy of the distance measuring sensor is poor at a short distance, and therefore the accuracy of the FB control is lowered. (6) In the extremely low speed state, detection accuracy of speed and acceleration is generally poor, and accuracy of FB control is lowered.

  In addition, as described above, when FF control is added to FB control at the start of follow-up traveling, the FB control is used as the main subject of control at the time of start-up. In particular, (3), (5), (6) There is a problem that the influence cannot be excluded. In addition, the FF control is performed according to a predetermined target value, and therefore, it cannot properly respond to fluctuations in the actual inter-vehicle distance or the speed of the start of the preceding vehicle, giving the driver a feeling of rattling, and in some cases There is also the possibility of over-acceleration control.

  It is an object of the present invention to realize a smooth and smooth start without fluctuation caused by control slack and the behavior of a preceding vehicle at the start of follow-up running.

To achieve the above object, following distance control device of the present invention, there is provided a follow-up running control device for a vehicle having a function of travel following the preceding vehicle, the own status of the acceleration of the preceding vehicle relative to the preceding vehicle Detection means for detecting the following state of the vehicle, determination means for determining whether or not the preceding vehicle has started, and a feed that changes according to the acceleration state of the preceding vehicle that is the following state detected by the detecting means A setting means for setting a target value for forward control; and a first travel for performing a follow-up travel control by the feedforward control based on the target value during an initial travel period after the determination means determines that the preceding vehicle has started. and control means, a calculating means for calculating a target value of the feedback control based on the distance between the preceding vehicle and the subject vehicle, based on the target value which the calculation means has calculated the feedback Second traveling control means for performing follow-up traveling control by control, and following the control of the second traveling control means from the following traveling control of the first traveling control means by the end of the initial traveling period. Control switching means for switching to travel control, and during the initial travel period, the target value of the feedback control that changes based on the follow-up travel control of the feedforward control becomes equal to or greater than the target value of the feedforward control. The control switching means controls the travel control of the host vehicle by following the feed-forward control following the end of the initial travel period when the target value of the feedback control reaches or exceeds the target value of the feed-forward control. It is characterized in that switching to the follow-up run control by the feedback control from ( Motomeko 1).

  In the case of the follow-up travel control device according to the first aspect of the present invention, when the judging means judges that the preceding vehicle has started, an FF that changes from time to time according to the follow-up situation of the own vehicle with respect to the preceding car based on the detection by the detecting means. The setting means sets the control target value. Then, by the travel control of the first travel control means, the host vehicle starts based on the set target value with the FF control corresponding to the timely start situation of the preceding vehicle.

  Therefore, it is possible to realize a smooth and smooth start without a delay such as FB control and fluctuation due to the behavior of the preceding vehicle. In the present invention, the “following state of the host vehicle with respect to the preceding vehicle” means the distance and relative speed between the preceding vehicle and the host vehicle, the acceleration of the preceding vehicle, the elapsed time from the start of the preceding vehicle (or the host vehicle), It is at least one of the situations such as running resistance including road gradient.

In addition , by setting the follow-up situation of the host vehicle with respect to the preceding vehicle as the situation of the momentary acceleration of the preceding vehicle, the target value of the FF control at the start is set based on the momentary acceleration situation of the preceding vehicle, for example, A smooth and smooth start can be realized by appropriately responding to the start and stop of the preceding vehicle.

Further , during the initial running period when the FB control becomes unstable from the start, the FF control makes a smooth and smooth start, and when the period passes and the FB control can stably follow the FB control, the FB control starts with the FB control. After switching to control, FB control can perform highly reliable follow-up running control, and in other words not only at the start but also after the start, in other words, good follow-up running control can be performed in the entire vehicle speed range.

Further , when the vehicle speed of the own vehicle increases following the preceding vehicle by the FF control at the time of starting, the inter-vehicle distance of the following traveling determined from the vehicle speed becomes long, and the target value of the FB control based on the inter-vehicle distance increases.

  When the target value of the FB control becomes equal to or higher than the target value of the FF control, the FF control is switched to the FB control, and thereafter, the FB control can be followed with high reliability without excess or deficiency.

  Next, in order to describe the present invention in more detail, an embodiment thereof will be described in detail with reference to FIGS.

  FIG. 1 is a block diagram of a control system of the follow-up travel control device of the present embodiment mounted on the own vehicle 1, and schematically shows a state in which the own vehicle 1 on the travel path follows the preceding vehicle α by the control. Is shown. FIG. 2 is a functional block diagram of the inter-vehicle controller 2 shown in FIG.

  FIG. 3 is a timing chart for explaining the operation when the own vehicle 1 starts from the travel stop state following the preceding vehicle α, and FIG. 4 is a timing chart for explaining the operation in more detail.

  The follow-up travel control device of FIG. 1 repeatedly searches the front of the own vehicle 1 while the vehicle is stopped by a known ranging radar 3. The ranging radar 3 is composed of, for example, a laser radar or a millimeter wave radar.

  Then, the search results in front of the ranging radar 3 every moment are taken into the inter-vehicle controller 2 having a computer configuration.

  The inter-vehicle controller 2 includes detection signals of various sensors of the vehicle 1 such as a brake pedal depression detection sensor, an accelerator throttle opening detection sensor, various switch open / close signals, a clock time signal, and a gyro road. A gradient signal or the like is also input.

  As shown in FIG. 2, the inter-vehicle controller 2 includes a detection unit 21 as a detection unit, a determination unit 22 as a determination unit, a setting unit 23 as a setting unit, and an FF control unit as a first travel control unit. 24, a calculation unit 25 as a calculation unit, an FB control unit 26 as a second traveling control unit, and an output processing unit 27 as a control switching unit. Each unit 21 to 27 is formed by software processing by executing a follow-up running control program in which the inter-vehicle distance controller 2 is set.

  Then, the detection unit 21 follows the own vehicle 1 with respect to the preceding vehicle α based on the search results of the ranging radar 3 from time to time, detection signals of various sensors, open / close signals of various switches, time signals, road gradient signals, and the like. Detect the situation. This follow-up situation includes the distance between the preceding vehicle α and the own vehicle 1 obtained from the search result (hereinafter referred to as the inter-vehicle distance), the relative speed, the acceleration of the preceding vehicle α, the start of the preceding vehicle α (or the own vehicle 1). It is the situation every moment of at least any one of the elapsed time from the road, the running resistance including the road gradient, etc.

  The determination unit 22 determines, for example, whether or not the preceding vehicle α has started by detecting a change in the speed of the preceding vehicle α from the change in the inter-vehicle distance.

  The setting unit 23 sets a target value for FF control that changes in accordance with the following situation detected by the detection unit 21. This target value is an FF target output set by a design specification or the like, or selected by a driver or the like in advance or selected by simulating a driver operation pattern acquired in advance. The engine torque, target acceleration, target accelerator opening, target throttle opening, or target speed. The FF target output is obtained from the acceleration of the preceding vehicle α (estimated from the change in the inter-vehicle distance), the inter-vehicle distance between the preceding vehicle α and the host vehicle 1, the relative speed, and the road gradient signal based on the design conditions and the like. Although it changes according to the situation of any element of a gradient (estimated value) and an FB target output (ordinary inter-vehicle control command value) to be described later calculated for FB control, in this embodiment, it is most preferable and practical. It changes according to the acceleration situation of the preceding vehicle.

  The FF control unit 24 has the same configuration as the well-known FF control unit, and the FF target output (target value) set by the setting unit 23 during the initial travel period after the determination unit 22 determines that the preceding vehicle α has started. Based on the above, follow-up running control by FF control is performed. The initial travel period includes (1) a certain time (time t2 to time t3 to be described later), (2) a time until the vehicle speed or acceleration reaches a certain value, and (3) an FB target output (normal inter-vehicle control command value). Or, the period in which the actual acceleration is unstable, and (4) the period in which the FF target output (control command value) <FB target output (normal inter-vehicle control command value) is reached by the FF control in the time of (1). In the embodiment, the period (4) is desirably set.

  For example, the calculation unit 25 calculates the target value of the FB control from moment to moment based on the inter-vehicle distance of the detection unit 21 while the engine of the host vehicle 1 is running. This target value (hereinafter referred to as FB target output) is a so-called inter-vehicle time safe distance, and increases in proportion to the vehicle speed of the host vehicle 1.

  The FB control unit 26 has the same configuration as the well-known FB control unit, and at least the follow-up travel control by the FB control based on the FB target output (target value) calculated by the calculation unit 25 at the end of the initial travel period. I do.

  The output processing unit 27 switches the travel control of the host vehicle 1 from the follow-up travel control (FF control) of the FF control unit 24 to the follow-up travel control (FB control) of the FB control unit 26 when the initial travel period ends. There is a switching function and a control synthesis function that adds the control output of the FB control unit to the control output of the FF control unit 24 at an appropriate ratio depending on the FF target output during the initial travel period.

  Next, the FF control output and the FB control output of the inter-vehicle controller 2 are supplied to the engine controller 4 and the brake controller 5 in FIG. 1, and the engine controller 4 controls the opening degree of the throttle (electronic throttle) 6. The own vehicle 1 is subjected to acceleration / deceleration control, and the brake controller 5 operates the actuator of the brake 7 when starting, decelerating, and stopping.

  Based on the above configuration, when the FF target output is the target engine torque, for example, the traffic signal switches from red to blue, and the preceding vehicle α starts from a state where both the preceding vehicle α and the own vehicle 1 are stopped (stopped). Then, when the vehicle 1 starts following this, it operates as shown in FIG.

  That is, based on the detection of the follow-up state of the detection unit 21, the determination unit 22 detects the start of the preceding vehicle α from the speed change of the preceding vehicle α in FIG. 3A at time t1, and the time t2 in FIG. When the automatic start operation (switch operation or the like) of the driver shown in FIG. 3 occurs, the control of the follow-up running of the inter-vehicle controller 2 is started using this operation as a trigger, and is set as indicated by a solid line in FIG. The unit 23 sets the FF target output, and the control engine torque is commanded. Based on this command, FF control is performed during the initial travel period from time t2 to time t3 of several seconds, in other words, while the host vehicle 1 starts and travels at an extremely low speed, and the speed of the host vehicle 1 is As shown in 3 (b), the temperature rises smoothly from time t3. In this case, in the case of FB control, the control target output fluctuates as shown by the broken line in FIG. 3D due to the behavior of the preceding vehicle α in the meantime, and the speed of the own vehicle 1 increases or decreases. However, because it is FF control, it is not easily affected by the behavior of the preceding vehicle α and the speed of the host vehicle 1 increases smoothly from time t3. The start is realized, the driver is not swayed, and no excessive acceleration occurs.

  In addition, when the time t3 is reached, the control is switched to the FB control to shift to the stable and accurate follow-up running control that keeps the inter-vehicle distance constant, so that the good follow-up running control can be performed over the entire speed range.

  Next, the FF control at the time of starting from time t2 to t3 will be described in detail with reference to FIG. 4A and 4B show changes in acceleration (preceding vehicle acceleration) and speed (preceding vehicle speed) of the preceding vehicle α, and (c) and (d) are accelerations of the own vehicle 1 (own vehicle acceleration). ), Changes in speed (vehicle speed), (e) shows the timing of the start operation, and (f) shows changes in the target engine torque, which is the FF target output.

  When a start condition such as start of the preceding vehicle α, start operation, etc. is established, at time t2, as a target value for FF control for starting the vehicle, the setting unit 23 is based on design specifications, selection settings of drivers, etc. One of the following FF target outputs (a) to (e) (including (f) in some cases) is set, and the FF control unit 24 starts the FF control.

  (A) A certain fixed value (a fixed value or a value that can be changed in accordance with a change in the inter-vehicle distance), for example, a value indicated by FF1 in FIG. 4D: the simplest but a control target is made constant Thus, a smoother and more stable start control is possible than the FB control of the broken line FB0 in FIG.

  (B) A value that depends on the acceleration of the preceding vehicle, for example, the value of FF2 in FIG. 4F obtained by multiplying the acceleration of the preceding vehicle α estimated from the change in the inter-vehicle distance by the gain: It is possible to effectively prevent the influence of the start and stop of the vehicle α.

  (C) Value that increases with time, for example, the value of FF3 in FIG. 4 (f): When set in this way, for example, when starting on a road with a running resistance such as an uphill, it is impossible to start due to insufficient torque. It can be avoided reliably.

  (D) A value that takes into account an expected traveling resistance value such as a road gradient, and has the same advantages as, for example, the value of (FF) FF4 in FIG.

  (E) A value obtained by combining all or part of the above (A) to (D), for example, the value of FF0 in FIG. 4F (specifically, based on the set addition ratio, for example, ), (B) value of 40%, (c), (d) value added at a rate of 10%): With this setting, the advantages of (b) to (c) are combined. Have.

  (F) A value set by adding FB control to FF control, for example, a value obtained as (K1 × FB0) + (K2 × FF0) where K1 and K2 are gain constants, and the FB target output is It is set with consideration.

  The FF control is performed during the initial running period from time t2 to time t3. Specifically, the time (several seconds) is set based on design specifications, selection settings of drivers, and the like. It is the time to reach any one of (A) to (O) or any one of those times.

  (A) a certain period, (i) a period until a certain value of the host vehicle speed or acceleration is generated, (e) a period in which, for example, the deviation between the target acceleration and the actual acceleration is large, (e) FB target output (inter-vehicle speed control command) Value) or a period during which the actual acceleration is unstable, (o) a period until the FF target output (for example, the control command value (FF0 or FF1 command value) <normal (after stabilization) FB target output).

  In particular, the (ii) time setting is suitable for a smooth start by FF control, and the (o) time setting also monitors the follow-up traveling of the preceding vehicle α. When the FF control is switched to the FB control at t3, as is apparent from the change characteristic of the own vehicle speed in FIG. 4D, the following traveling control in the entire vehicle speed region which is extremely smooth and does not have excessive or insufficient acceleration is realized. In addition, when it is not easy to determine whether (e) is unstable or stable, it can be either (a), (i), (u), (o), or the time to reach one of them. It may be.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention.

  For example, in the above embodiment, the target engine torque is described as the target value of the FF control. However, the engine output is obtained from acceleration × mass (vehicle weight), the engine torque is obtained from engine output ÷ rotation speed, and the engine torque As described above, the target value for FF control can be any of the target engine output, target engine torque, target acceleration, target accelerator opening, target throttle opening, and target speed. Even if any of these values is set as the target value of the FF control, the follow-up running control equivalent to that in the above embodiment is realized.

  The present invention can be similarly applied not only to an engine-driven vehicle but also to follow-up control of various vehicles such as a battery-powered vehicle and a hybrid vehicle by replacing the engine with a motor.

It is a block diagram of a control system of one embodiment of the present invention. It is a detailed functional block diagram of FIG. It is a timing chart of operation | movement description of FIG. It is a timing chart of detailed operation | movement description of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Own vehicle 2 Inter-vehicle controller 21 Detection part 22 Judgment part 23 Setting part 24 FF control part 25 Calculation part 26 FB control part 27 Output processing part (alpha) Predecessor vehicle

Claims (1)

A vehicle tracking control device having a function of following a preceding vehicle,
Detecting means for detecting the state of acceleration of the preceding vehicle as the following state of the vehicle relative to the preceding vehicle;
A determination means for determining whether or not the preceding vehicle has started;
Setting means for setting a target value for feedforward control that changes in accordance with the state of acceleration of the preceding vehicle, which is the follow-up situation detected by the detection means;
First traveling control means for performing follow-up traveling control by the feedforward control based on the target value during an initial traveling period after it is determined by the determining means that the preceding vehicle has started ;
A calculation means for calculating a target value of feedback control based on a distance between the preceding vehicle and the own vehicle;
Second traveling control means for performing follow-up traveling control by the feedback control based on the target value calculated by the calculating means;
A control switching means for switching the running control of the vehicle from the follow-up running control of the first running control means to the follow-up running control of the second running control means at the end of the initial running period ;
The initial travel period is a period until the target value of the feedback control that changes based on the follow-up travel control of the feedforward control becomes equal to or greater than the target value of the feedforward control, and the target value of the feedback control is When the initial travel period ends due to reaching the feedforward control target value or more, the control switching means switches the travel control of the vehicle from the follow-up travel control of the feedforward control to the follow-up travel control by the feedback control. A follow-up running control device characterized by the above.

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