JPH06320984A - Vehicle speed control device - Google Patents

Abstract

PURPOSE:To eliminate the fluctuation of a target vehicle speed by stopping the speed control of a vehicle and holding the value of a control variable on the basis of a distance to a preceding vehicle, when the preceding vehicle is no longer detected, in controlling the speed of the vehicle on the basis of the distance to the preceding vehicle. CONSTITUTION:An auto-cruising system detects a distance between a preceding vehicle and a vehicle with a distance sensor 10, and further detects the speed of the vehicle with a speed sensor 51. Also, an engine 40 is controlled with a control unit 20, on the basis of signals detected with sensors 10 and 51, and an output signal from an operation device group 60. In this case, the control unit 20 performs arithmetic operation about a control variable according to the prescribed process, on the basis of the detected distance to the preceding vehicle, and holds a distance to the vehicle at the preset target value, depending upon the resulting control variable. On the other hand, the sensor 10 estimates possibility to catch up with the preceding vehicle. As a result, when the preceding vehicle can be no longer detected, auto-cruising mode is stopped and, at the same time, the value of the control variable is maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle speed control system, and more particularly to a vehicle speed control system capable of performing inter-vehicle type F / B control.

[0002]

2. Description of the Related Art The automatic cruise function is a vehicle speed type F / B control in which the vehicle speed of the vehicle is automatically maintained at a target vehicle speed set by the driver, and the inter-vehicle distance to the preceding vehicle is set to a distance set by the driver. There is a headway distance type F / B control. Many automobiles having such an auto cruise function have been proposed.

For example, JP-A-63-269736 discloses
In a vehicle that has both vehicle speed type F / B control and vehicle distance type F / B control, by changing the control constant for the vehicle distance type F / B control according to the traveling situation during auto cruise, The goal is to converge with good responsiveness. Further, Japanese Patent Laid-Open No. 3-118700 is to set a target vehicle distance according to a road surface friction coefficient in an inter-vehicle F / B control type auto cruise.

Further, Japanese Patent Laid-Open No. 61-150835 discloses that, in a vehicle having both vehicle speed type F / B control and inter-vehicle type F / B control, when the inter-vehicle distance cannot be detected, this detection cannot be performed. The vehicle speed type F / B is performed based on the previous vehicle speed. Further, in Japanese Patent Application Laid-Open No. 61-6034, a vehicle speed type F / B control device sets a target vehicle speed during a curve traveling to a value commensurate with the curvature of the curve, so that the curve has an appropriate target vehicle speed. I am able to drive.

A vehicle speed type F disclosed in Japanese Patent Laid-Open No. 58-29018
In the / B-controlled vehicle speed control device, the acceleration of the driving vehicle during normal driving is detected, and the acceleration is stored and learned in correspondence with the acceleration occurrence frequency. Through this learning, the acceleration when the vehicle speed type F / B control state is released and acceleration is performed in the normal traveling state, or when the vehicle speed type F / B control is returned to the vehicle speed type F / B control from the normal traveling state (ie , Learned acceleration).

[0006]

By the way, an inter-vehicle type F /
A problem for a vehicle speed controller with B control is that it loses sight of the vehicle in front. This is because if the vehicle ahead is lost, the inter-vehicle type F / B control becomes impossible. In the above-mentioned Japanese Patent Laid-Open No. 61-150835, when the inter-vehicle distance cannot be detected, the inter-vehicle type F / B control is shifted to the vehicle speed type F / B control.
Since stopping the B control and performing the vehicle speed type F / B control means starting another new feedback control, as a matter of course, the feedback control for the following inter-vehicle type F / B control is performed. The value of the variable is reset, the control variable of the vehicle speed type F / B control is newly calculated, and the vehicle speed type F / B control is performed based on the new control variable.

Therefore, the continuity of control is lost when shifting from the inter-vehicle type F / B to the vehicle speed type F / B, and in extreme cases, the vehicle speed and the vehicle speed type F / B immediately before the inter-vehicle type F / B is stopped.
A large difference occurs between the vehicle speed immediately after the start of B and the driver feels uncomfortable. This problem becomes noticeable in the following cases. That is, there are various causes for losing the sight of the vehicle ahead, but rather than when the vehicle ahead actually leaves the road and detects the disappearance (true disappearance), the vehicle body of the own vehicle makes a pitch motion to detect the distance sensor. It is recognized that the front vehicle has disappeared because the direction of detection of the vehicle does not correctly face forward, or the direction of the sensor and the traveling direction of the front vehicle do not match when traveling on a curve (temporary disappearance =
The possibility of false recognition is higher as a practical problem.
In the case of such a temporary signal loss, the inter-vehicle type F / B control is stopped and the vehicle speed type F / B control is performed.
When the signal is restored and the vehicle-type F / B control is resumed, the loss of continuity of the control variable causes the driver to feel a sense of discomfort due to the loss of continuity of the vehicle speed change.

[0008]

Therefore, the present invention has been proposed in order to solve the above-mentioned drawbacks of the prior art, and its object is an inter-vehicle type F for keeping a vehicle-to-vehicle distance to a preceding vehicle at a predetermined distance.
In a vehicle speed control device that performs / B control, an inter-vehicle type F / B control from an inter-vehicle type F / B control to a vehicle speed type F when a preceding vehicle disappears during auto cruise.
The present invention proposes a vehicle speed control device that does not make a driver feel uncomfortable by eliminating a large change in the target vehicle speed when shifting to / B control.

A further object of the present invention is to shift from the inter-vehicle type F / B control to the vehicle speed type F / B control and to return to the inter-vehicle type F / B control more smoothly even in the case of a temporary loss of the vehicle ahead. The present invention proposes a vehicle speed control device that can be used. The configuration of the present invention for achieving the above object is
A distance sensor that detects a distance to a front object, a unit that calculates a predetermined control variable based on an output signal from the sensor, and an inter-vehicle distance to a vehicle ahead, a predetermined target based on the calculated control variable. An inter-vehicle distance type auto-cruise means for maintaining a vehicle-to-vehicle distance, a means for estimating whether the distance sensor is in a state of being able to capture a front vehicle, and when it is estimated that the front vehicle is not capable of capturing a front vehicle, A holding means for stopping the operation of the inter-vehicle distance type auto-cruise means and holding the value of the control variable is also provided.

According to the present invention as described above, the value of the held control variable is set to the inter-vehicular auto-cruise mode again when the loss of signal is restored when the inter-vehicular auto-cruise shifts to the vehicle-speed auto-cruise. It can be used even after returning to, so that the continuity of vehicle speed can be secured.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. <System Configuration> FIG. 1 shows the configuration of an auto cruise system to which the present invention is applied. This system is provided with feedback control that maintains the vehicle speed of the host vehicle at an appropriate vehicle speed (hereinafter abbreviated as "vehicle speed type F / B control") and feedback control that maintains an appropriate inter-vehicle distance with respect to the preceding vehicle (hereinafter ,
It is a system capable of performing "inter-vehicle type F / B control". The main component is the distance sensor 10 for detecting the distance to the vehicle in front (or the object ahead).
A vehicle speed sensor 51 (mounted on the rear wheel 50) for detecting the vehicle speed of the host vehicle, the engine 40, and the operating devices 6
0, and a control unit 20 for executing the control of the embodiment. The system of this embodiment changes the speed of the host vehicle in order to keep the vehicle speed constant or the inter-vehicle distance constant. The speed of the vehicle is controlled by the throttle actuator 43 controlling the opening of the throttle valve 42. The control unit 20 controls the throttle actuator 43.

First, the outline of the automatic cruise function will be briefly described. When the driver is about to start an auto cruise, he must turn on the MAIN switch. Turning on this switch enables auto cruise. In order for the auto cruise to actually start, you have to press the SET switch once. When the SET switch is pressed, the vehicle speed type F / B control (or the vehicle type F / B control) is performed according to the vehicle speed (or the vehicle distance) at that time. After that, unless the auto cruise mode is released, the present auto cruise system controls the vehicle speed or the inter-vehicle distance. When the driver presses the RESUME switch,
When the SET switch is pressed, the target vehicle speed TGV or the target inter-vehicle distance TGD that has been retracted is restored. COAST
When the switch is pressed, the vehicle speed gradually decreases or the inter-vehicle distance decreases.

FIG. 2 is a functional block diagram showing an outline of control performed by the system shown in FIG. The control procedure of this system is roughly the main routine 10
0, a block 200 that determines whether or not the signal from the preceding vehicle has disappeared, a block 300 that determines whether the inter-vehicle distance sensor 10 has deteriorated in its function due to, for example, rain or mud, and Block 400 for determining whether the vehicle is turning, and inter-vehicle type F / B control or vehicle speed type F
/ B control is executed to calculate a target throttle opening degree, and a learning block 900 is used. In the control procedure of the embodiment described below, the control procedure of the turning / acceleration determination block 400 is the learning block 9
00 is incorporated in the control procedure (FIGS. 14 to 15).
Figure). <Simplification of Operation> One of the features of the automatic cruise system of this embodiment is simplification of the operation switch. This simplification will be made clearer by understanding what kind of control is started when the operation switch 65 is operated. Therefore, various operating states will be described below as examples, and how the control of the embodiment operates according to the individual operating states will be described with reference to the attached flowcharts.

It should be noted that there are three important points used in this system.
The two control variables will be explained first. TG: Target throttle opening register. It is output to the actuator 43 using the value stored in TG. TGV: Target vehicle speed register used in vehicle speed type F / B control. In the vehicle speed type F / B control, the target throttle opening degree TG is determined based on the deviation between the TGV and the current vehicle speed Vn.

TGD: Target distance register used in the distance type F / B control. In the inter-vehicle type F / B control, T
The target throttle opening degree TG is determined based on the deviation between GD and the current vehicle distance Dn. First, the main routine of FIG. 3 will be described. This main routine makes it clear how the operation is simplified in this system.

In step S101, various signals are input. Here, the signals include the range signal R from the selector 67, the brake signal Br from the brake switch 66, the accelerator opening α from the accelerator opening sensor 64, the RESUMESW signal output from the switch 65 used for general purpose, and the like. SE
TSW signal, COASTSW signal, etc., MAINSW signal from MAIN switch 63, steering angle θ showing steering angle of steering wheel 62
And a WP signal indicating whether or not the wiper is operating, a vehicle speed signal vn indicating a current vehicle speed from the vehicle speed sensor 51, a signal Dn indicating a current inter-vehicle distance from the distance sensor 10. The inter-vehicle distance Dn-1 measured in the previous control cycle
The vehicle speed Vn-1 and the like are stored in a memory (not shown) in the control unit 20. Signal MAINSW and signal RESUMESW will be 0 when non-auto cruise is required. Therefore, after confirming that the signal MAINSW is 0 in step S102, the contents of various flags and registers used in the control procedure are initialized. Further, step S1
At 72 (FIG. 5), it is confirmed that the signal RESUMESW is 0, and at step S196, the target throttle opening TG corresponding to the accelerator opening α is determined according to the characteristic shown in FIG. 7, and the TG is set at step S198. Actuator 43
Output to. In this way, normal throttle opening control is performed during non-auto cruise. When the main switch is turned on, step S102 → step S104 → step S140 → step S172 → step S180
→ Proceeds to step S196 → step S198 to perform normal throttle control. SET switch on for a short time The SET switch is generally for setting the current vehicle speed to the cruise speed for auto-cruise. In this system, as described above, the vehicle speed type F / B control and the headway type F / B control are performed.
Since both the A / B control can be executed, if the inter-vehicle type F / B control is performed when the set switch is pressed, the inter-vehicle distance D with the preceding vehicle measured at that time is detected.
When n is the target inter-vehicle distance TGD and the vehicle speed type F / B control is performed when the vehicle distance is pressed, the own vehicle speed Vn at that time
Becomes the target vehicle speed TGV.

First, when it is detected in step S104 that SETSW is 1, the flag SET is set in step S106, and the fact that the switch has been pressed is stored. Then, after confirming that the button has been pressed for a short time (0.5 seconds), the flag RESUME is reset in step S130, and the state of the flag DV is confirmed in step S132. This flag DV stores the mode of F / B currently being performed. If DV = 1, the inter-vehicle F / B control is DV = 0.
If so, it means that the vehicle speed type F / B control is being performed. Therefore, if DV = 0 (vehicle speed type F / B control), the current vehicle speed Vn is set to the target vehicle speed (TGV = Vn) in step S134, and the register MT is set in step S136.
The vehicle speed Vn is also set to GV. This auto cruise system automatically switches between vehicle speed type F / B control and inter-vehicle type F / B control independently of the driver's operation, so the target vehicle speed required at the time of automatic switching is set. The MTGV is used for storing (step S524 in FIG. 9).

In steps S142 to S152, it is determined whether or not the environment for the auto cruise is prepared. The conditions to enable auto cruise are:
The current vehicle speed Vn is 40 Km / h or more and 120 Km / h or less (step S142), and the brake is not depressed (step S142).
144), the selector 67 is not in the R (reverse) range (step S146), and the accelerator is not stepped on (step S152).

Even if the SET switch is pressed, as long as the accelerator is stepped on, step S152 → step S1
In the order of 72 → step S178 → step S196 → step S198, normal throttle control is performed. When the accelerator is released, the process proceeds from step S152 to step S154, and after confirming that the COAST switch is off, the process returns to step S101. The target vehicle speed TGV set in step S134
Based on the vehicle speed type F / B control or the vehicle type F / B control based on the target vehicle distance TGD set in step S138, a feedback routine (FIGS. 9 to 11) described later is performed.
Figure) will be described in detail.

Steps S142 to S152 show conditions for canceling the auto cruise mode. That is, when the current vehicle speed Vn is less than 40 km / h or more than 120 km / h (step S142), or when the brake is depressed (step S144), or the selector 67 is R
When the range is entered (step S146), the flag SET indicating that the auto-cruise is being performed and the flag RESUME indicating that the RESUME operation is being performed are reset in steps S148 and S152.
However, when it is detected that the driver depresses the accelerator during the auto cruise (YE in step S152)
In S), in order to prioritize the driver's willingness to accelerate, step S172 → step S178 → 196
→ Throttle control is normally performed in step S198, but since such acceleration is often transient, the auto cruise mode is not reset. That is, the flag SET
Is not reset. Turning on the SET switch for 0.5 seconds or longer It means that the driver intends to accelerate in this auto cruise system if the SET switch is turned on continuously for 0.5 seconds or longer. Therefore, in such a case, not only the target throttle opening degree that allows further acceleration with a predetermined acceleration is selected from the vehicle speed Vn at that time, but also the vehicle speed type F / B control is forcibly shifted.

That is, in step S110, the target throttle opening TG corresponding to the vehicle speed Vn at that time is detected according to the characteristics shown in FIG. This target opening TG is
It is a throttle opening TG (see FIG. 8) that can be accelerated at a constant acceleration a for traveling on a flat ground or a flat ground. Then, in step S121, the flag DV is reset, and the subsequent control is the vehicle speed type F / B control. And step S1
22 (FIG. 6) to output the throttle opening TG to the actuator 43 so that the acceleration a can be obtained.

In step S112, the flag DV is checked and the current inter-vehicle distance Dn is saved in the TGD (step S116), depending on whether the inter-vehicle type F / B control or the vehicle speed type F / B control is performed. Vehicle speed Vn of TGV, MT
It saves to GV (step S118, step S120). However, in step S114, if it is estimated that the function of the inter-vehicle distance sensor may be deteriorated due to, for example, rain (flag FAIL = 1) or if the preceding vehicle is lost (flag VF = 1), the metaphor distance type Even if the F / B control is being performed (DV = 1), the process proceeds to step S118 and the current vehicle speed Vn is set to TGV and MTGV.

Even if the SET switch is released, since the flag SET has already been set in step S106, the control procedure is step S104 → step S140 → step S142 → step S144 → step S146 →
The process proceeds from step S152 to step S154. The control when the SET flag is set is performed according to the control procedure shown in the flowchart of "feedback control" in FIGS. 9 to 11. RESUME switch on Next, the case where the RESUME switch is pressed will be described. In such a case, the process proceeds from step S172 to step S176, the flag RESUME is set, and in step S184, the throttle opening TG at which the predetermined acceleration a is obtained for the current vehicle speed Vn is determined, and in step S122 the TG
Is output to the actuator 43. Then, the operation of outputting the target throttle opening degree TG to obtain the above-mentioned acceleration to the actuator 43 is performed in step S182.
Then, whether the vehicle speed is within ± 3 km / h of the target speed TGV,
Alternatively, in step S190, the inter-vehicle distance is the target inter-vehicle distance T
Continue until it is confirmed that it is within ± 1m of GD. That is, in the case of the inter-vehicle type F / B control (step S180
To YES) until the target inter-vehicle distance TGD stored in step S138 is restored, or in the vehicle speed type F / B control mode (NO in step S180), the target vehicle speed TGV set in step S134 is restored. Acceleration or deceleration is performed until.

While the RESUME flag is set (that is, during the operation of returning to the target vehicle speed or the target inter-vehicle distance), if the vehicle approaches the target vehicle speed (step S182) or the target inter-vehicle distance (step S190), the flag RESUME is reached in step S187. Is reset and the flag SET is set. If the flag SET is set, the subsequent throttle opening control is performed according to the feedback control shown in FIGS.

In step S192, it is checked whether the distance between the target vehicles is too close in the inter-vehicle type F / B control during the RESUME operation. In the present embodiment, Dn <TGD-1 (1) That is, the actual inter-vehicle distance Dn is 1 m further than the target inter-vehicle distance TGD.
When approaching too much beyond the above, step S194
To throttle and slow down. COAST switch on Decelerates when the COAST switch is turned on during auto cruise. That is, when it is detected that the switch is turned on in step S154 during the auto cruise, step S154
The target throttle opening degree TG is set to 0 at 156, and the TG is output to the actuator 43 to decelerate at step S122. It should be noted that the vehicle speed or the inter-vehicle distance when this switch is pressed is set to the future vehicle speed type F / B control or the inter-vehicle type F.
In order to obtain the target vehicle speed TGV or the target inter-vehicle distance TGD for the / B control, the vehicle speed Vn or the inter-vehicle distance Dn is set to T.
Save to GV or TGD (steps S162, S
160). <Vehicle speed type F / B control> In this system, the driver is SE
When the T switch is pressed, the flag SET is set (step S1
06), and the vehicle speed at that time is set to the target vehicle speed (step S13).
The automatic cruise is performed according to the vehicle speed type F / B control described in 4). The reason why the vehicle speed type F / B control is performed in a short period is that both the flag DV and the flag LCKON are reset in the initialization processing of step S170. On the other hand, when the driver presses the RESUME switch, acceleration / deceleration is performed toward the previously set target vehicle speed (step S184). After the target vehicle speed is reached (YES in step S182), step S
A flag SET is set at 187 to perform vehicle speed type F / B control. That is, even when the RESUME switch is pressed to perform the auto cruise, the vehicle speed type F / B control is performed after the target vehicle speed is reached, as in the case where the SET switch is pressed to perform the auto cruise.

In FIG. 12, after the RESUME flag is set, the vehicle speed increases (accelerating operation) to reach the target vehicle speed TGV, the SET flag is set (vehicle speed type F / B control operation), and then the vehicle ahead. The distance between cars has become shorter, and flag D
It shows until V is set. 9th vehicle speed type F / B control
This will be described with reference to the flowcharts of FIGS. 9th
The flowcharts of FIGS. 11 to 11 include both vehicle speed type F / B control and inter-vehicle type F / B control. The calculation of the vehicle speed type F / B control is performed in step S596, and the calculation of the inter-vehicle type F / B control is performed in step S566. First, vehicle speed type F
/ B control will be explained, and then the vehicle speed type F / B control to the headway type F
The conditions for shifting to the / B control will be described, and then the inter-vehicle type F / B control will be described. Execution of vehicle speed type F / B control Target throttle opening T in vehicle speed type F / B control mode
G is defined by the _{TG = K vI × E vI ...} (2) + K vP × E n ... (3) -K vP (V n-1 -V n) ... (4). Here, K _vI and K _vP are control constants, and are defined by E _n = TGV-V _n (5) E _vI = E _vI + En (6) Therefore, the term (2) is the integral control term,
It has the effect of stabilizing the feedback control. (3)
The term is a proportional control term, and the term 4) is a derivative control term, which has the effect of quickly converging to the target value. (2)
The calculation of expressions (4) is performed in steps S596 and S59.
Done at 8.

Returning to FIG. 9, it is checked in step S501 if the flag SET is set. If it is not set, nothing is done in the flowcharts of FIGS. That is, the vehicle speed type F / B control and the inter-vehicle type F / B control are performed only after the flag SET is set. The case where the flag SET is set will be described.

In step S502, the flag ISD is checked. The ISD flag is a flag that is set when the inter-vehicle type F / B control mode is first entered and is normally reset when the vehicle speed type F / B control is performed. Therefore, control proceeds to step S504. In step S504, it is checked whether the current inter-vehicle distance Dn to the preceding vehicle has approached the distance Ds enough to perform inter-vehicle type F / B control. For a while after the auto cruise is started, Dn> Ds (7) will be satisfied (YES in step S504). Therefore, the process proceeds to step S506. In step S506, the flag ISV is checked. This flag ISV is a flag that is set when the vehicle speed type F / B control mode is entered for the first time, and therefore control proceeds from step S506 to step S508. That is, each time the vehicle speed type F / B control mode is entered for the first time, steps S508 to S518 are performed.

In step S508, the integral value E of the item (2) is calculated.
_vI , and further, an integrated value E _dI (described later) of the inter-vehicle type F / B control is initialized to 0. Steps S510 and S51
2. In step S518, flag ISD and flag D, respectively
Reset the V and flag ISF. And step S516
The flag ISV is set to 1 in order to remember that the vehicle speed type F / B control mode has been entered. And step S59
Go to 2.

In step S592 (FIG. 11),
The deviation between the vehicle speed Vn and the target vehicle speed TGV is calculated according to the equation (5), the integral variable E _vI is calculated according to the equation (6) in step S594, and the target is calculated according to the equations (2) to (4) in steps S596 and S598. Calculate the throttle opening. In step S602, the fact that the vehicle is traveling in the vehicle speed type F / B control mode is displayed to inform the driver. In step S606, the target throttle opening TG is output to the actuator 43.

Once the flag ISV is set, the inter-vehicle distance Dn to the preceding vehicle is the inter-vehicle F / B controllable distance Ds.
As long as it does not exceed, it is determined to be NO in step S506, so the integral variable E _vI accumulates the deviation from the target vehicle speed TGV. FIG. 13 shows that the vehicle speed Vn approaches the target vehicle speed TGV and then converges to the TGV. That is, while the vehicle speed Vn is smaller than the target value TGV, the integral variable E _vI increases, but when the vehicle speed Vn converges to the target value TGV, the integral variable E _vI also converges to a constant value. Transition to inter-vehicle F / B control If the set vehicle speed TGV is higher than the vehicle speed of the vehicle ahead, the own vehicle will soon catch up with the vehicle ahead. Eventually, NO is determined in step S504, and the process proceeds to step S520.

In steps S520 and S528, there is no functional deterioration of the inter-vehicle distance sensor (step S52).
0), or make sure that you have not lost sight of the vehicle in front of you due to your own pitch movement, etc.
Proceeding to 540, it is determined whether or not the turning operation is currently being performed (flag TRN = 1). For simplification of the explanation, it is assumed that the vehicle is moving straight ahead. Then, the control is step S54.
Go to 2.

In step S542, the flag IST is reset. Since this flag IST indicates that the turning motion has started, it is reset during straight traveling. In step S544, the flag ISD is checked. This flag stores that the vehicle speed type F / B control has been changed to the inter-vehicle type F / B control. Therefore, since the vehicle is in the distance where the inter-vehicle type F / B control is possible, it is reset now, so the control is performed in step S5.
Proceed to 46. In steps S546 to S560, the target inter-vehicle distance TGD is set and the integral variable E _dI is initialized in response to the new inter-vehicle F / B control.

That is, in step S546, it is determined how many times the target inter-vehicle distance TGD has been learned in the past. This learning will be described in detail later, but it is assumed that the number of learning times n _ij is small and that n _ij ≤n _s (8). Here, n _s is a predetermined constant representing the number of times of learning that should be determined by experience. The process proceeds from step S546 to step S550, and the target inter-vehicle distance TGD is set to the empirically determined distance D _SS . In step S552, E _dI is reset to 0 in order to reflect the new transition to the inter-vehicle type F / B control on the control, and step S55
4. In step S556, the flag IST and the flag ISV are reset, and in step S558, the flag DV is set to 1 in order to store the fact that the inter-vehicle F / B control has been performed.
In step S560, the flag ISD is set to 1 in order to store that the initialization for starting the inter-vehicle type F / B control (step S552) is completed. Step S56
In steps 2 to S566, the calculation for the inter-vehicle type F / B control is performed.

The target throttle opening TG in the inter-vehicle type F / B control mode is TG = K _dI × E _dI (10) + K _dP × E _n (11) -K _dD (D _n-1 -D _n ). Is defined by (12). Here, K _dI and K _dP are control constants, and are defined by E _n = TGD-D _n (13) E _dI = E _dI + E _n (14) As in the case of vehicle speed type F / B control,
The term (10) is an integral control term, and there is a term for stabilizing the feedback control. The term (11) is a proportional control term and has an effect of promptly converging to the target value. (12)
The term is a differential control term.

In steps S568 to S574, it is determined whether or not the target front vehicle is caught within the target inter-vehicle distance. That is, in step S568, the set state of the flag LCKON indicating that the vehicle ahead is captured is checked, and if it has already been set, step S568 is performed as it is.
If not, the process proceeds to step S57.
At 0, it is checked whether the actual inter-vehicle distance Dn has approached the target inter-vehicle distance TGD. That is, if | TGD-Dn | <ε ₀ (15), it is determined that the two approaches. Therefore, step S570
If YES is determined in step S572, the flag is set in step S572.
LCKON is set to 1, and if NO is determined, the flag LCKON is reset to 0 in step S574. Then, in step S576, the target throttle opening is set, and in steps S600 and S604, it is displayed on the display to indicate that the inter-vehicle type F / B control is being performed, and is output to the actuator 43 in step S606.

In FIG. 12, the flag ISD is set at the time point t ₁ when it is judged that Dn> Ds, and | TGD-
The flag LCKON is set at time t _{2 when} Dn│ <D ₀ (D ₀ is a constant). Once the flag ISD is set, step S54 is performed unless the turning motion is performed.
4 → step S562 → step S564 ...
Car-to-car type F / B control is performed. <Inter-Vehicle Distance Setting According to Driver> The meaning of step S548 performed during inter-vehicle F / B control will be described.

In the inter-vehicle type F / B control, there is a strong "habit" of the driver in obtaining the inter-vehicle distance. Some drivers will have longer distances, and some drivers will have shorter distances. As described above, in the present system, the inter-vehicle distance can be set to the standard inter-vehicle distance D _SS in step S550. However, it is desirable that the system automatically set the inter-vehicle distance according to the driver's preference. Therefore, in the present system, another routine (14th step) is executed in step S548.
The inter-vehicle distance [D _ij ] set by FIGS. 15 to 15 is set as the target inter-vehicle distance TGD. How the inter-vehicle distance [D _ij ] is set will be described with reference to the flowcharts of FIGS. 14 to 15.

If the driver's method of obtaining the vehicle-to-vehicle distance and the standard vehicle-to-vehicle distance D _SS set by the system do not match each other, this frequently appears as cancellation of the auto-cruise. This is because in this system, the auto cruise starts with the vehicle speed type F / B control, and the inter-vehicle distance is the distance D that can be controlled by the vehicle type F / B control.
When approaching s, the inter-vehicle F / B control is started, and the inter-vehicle F / B control is continued toward the standard inter-vehicle distance D _SS . If the standard distance D _SS is too short, the driver will step on the brakes, and if it is too long, he will step on the accelerator.

In this system, the "habit" of the driver regarding the inter-vehicle distance is learned during acceleration while traveling straight ahead.
The control procedures shown in the flowcharts of FIGS. 14 to 15 are executed in parallel with the control procedures of FIGS. 9 to 11. While the vehicle is traveling straight, it is determined in step S902 that the current steering angle θn is in the neutral state (= N). In step S904, it is confirmed that the flag TRN indicating that the vehicle is turning is reset, and the process proceeds to step S916. In step S916, it is determined whether the acceleration operation (Vn> Vn-1) has started. Step S916 → Step S while cruising
In the order of 940, step S930, step S934, and step S936, the acceleration flag ACC is reset, the acceleration timer ACCTMR is reset, and the acceleration integrated distance Dt is reset.

The acceleration state (Vn> Vn-1) is step S94.
If it is detected at 0, the flag ACC is set at step S942, the vehicle speed Vn at that time is stored in the acceleration start vehicle speed VSPST at step S944, and the timer ACCTMR which stores the number of times the acceleration state is detected at step S946 is set to 1 Increment only. Then, in step S948, the acceleration integration distance Dt is integrated. That is, in step S948, Dt = Dt + Dn (16)

Once the acceleration flag ACC is set,
Unless the vehicle speed decreases (Vn> Vn-1), step S
902-> step S904-> step S916-> step S918-> step S946-> step S948, the timer ACCTMR is counted up, and the accumulated distance Dt
Is accumulated. When deceleration is detected in step S918,
In step S920, the vehicle speed Vn at that time is saved in the vehicle speed register VSPEND at the end of acceleration. In step S922,
The average vehicle speed Vm during the acceleration period, the vehicle speed VSP at the start of acceleration
Calculate as the average value of ST and vehicle speed VSPEND at the end of acceleration, based on Vm = (VSPST + VSPEND) / 2 (17). In step S924, the average acceleration Gm during the acceleration period is calculated as the difference between the vehicle speed VSPST at the start of acceleration and the vehicle speed VSPEND at the end of acceleration, based on Gm = (VSPEND-VSPST) / ACCTMR (18). In step S926, the average inter-vehicle distance Dm during the acceleration period is calculated based on Dm = Dt / ACCTMR (19).

In step S928, the inter-vehicle distance Dm during the acceleration period is learned. The inter-vehicle distance in which the driver's individuality appears varies depending on the vehicle speed and acceleration at that time. Therefore,
In this system, the population for learning the inter-vehicle distance Dm is made different according to the average vehicle speed Vm and the average acceleration Gm. FIG. 16 shows the distinction of the population for learning the inter-vehicle distance. That is, in this system, the acceleration Gm can be set to 2
The vehicle speed Vm is divided into two groups of high speed and low speed. Then, as shown in FIG. 16, a small G
Population of m and low vehicle speed vm (represented by subscript (1, 1)), small G
Population of m and high vehicle speed vm (represented by subscript (1, 2)), large G
Population of m and low vehicle speed vm (represented by subscript (2, 1)), large G
For each of the four populations of m and the population of high vehicle speed vm (represented by subscript (2, 2)), the number of samples n _{ij in} the population and the learning average inter-vehicle distance [D _ij ] are learned. That is, the learning of the number of samples n _ij is performed as follows: n _ij = n _ij +1 (20) each time the acceleration is performed and the acceleration is finished, and the learning of the average inter-vehicle distance is [D _ij ] = (D _ij + Dm) / n _ij (21) When the average inter-vehicle distance [D _ij ] is learned by changing the population for each average vehicle speed Vm and each average acceleration Gm, the [D _ij ] should reflect the driver's habit. is there. FIG. 17 illustrates the concept of learning the target inter-vehicle distance during the acceleration period. Then, if the learning number _nij becomes sufficiently large, the learning accuracy should have increased, and therefore step S54 in FIG.
The target inter-vehicle distance [D _ij ] at 8 is set to the register V at that time.
It is obtained by searching the table of FIG. 16 according to the average vehicle speed and the average acceleration stored in m and Gm (these should be the latest average vehicle speed and average acceleration). This inter-vehicle distance [D _ij ] should best match the driver's "habit" at the time of the average vehicle speed and average acceleration, and the inter-vehicle distance F targeting such inter-vehicle distance [D _ij ]
When the / B control is performed, an inter-vehicle type F / B control without a feeling of strangeness is automatically performed. <Determination of Turning Motion> In this auto cruise system, if the vehicle is in an environment capable of simultaneously executing the vehicle speed type F / B control and the inter-vehicle type F / B control, the inter-vehicle type F / B control is prioritized. . This is because as long as only the vehicle speed type F / B control is performed, the vehicle will soon come close to the vehicle in front, so that the operation for changing the set speed is necessary and the operation is troublesome. Therefore, as described above, when the inter-vehicle distance reaches a distance at which the inter-vehicle F / B control can be executed in the course of performing the inter-vehicle F / B control, the inter-vehicle F / B control is switched to. I have to. However, even when a vehicle enters a curve while traveling with the inter-vehicle type F / B control, the inter-vehicle type F / B control is performed.
Continuing the control is not preferable because it keeps the distance between the vehicle ahead and the vehicle ahead when entering the curve.
Further, in a curve, for example, there is a high possibility that the guardrail is erroneously determined to be a vehicle ahead, and it is even less preferable to perform the inter-vehicle type F / B control. Therefore, in this system,
If the vehicle enters a curve during the inter-vehicle type F / B control, the vehicle speed type F / B control is switched to.

In the vehicle speed type F / B control during turning, the target vehicle speed becomes a problem. This is because the target vehicle speed while traveling straight ahead is too high. In this system, by learning the approach speed VSPST and the exit speed VSTEND before and after a curve run, a safe target vehicle speed that matches the driver's preference is automatically set. That is, the vehicle speed Vn at the time of entering a curve is set as a temporary target vehicle speed TGV, and thereafter, the target vehicle speed TGV is gradually decelerated at an acceleration / deceleration G _ij according to the past learning result. Therefore, first, the determination logic of the turning motion in this system will be described with reference to the flowcharts of FIGS. 14 to 15, and then the transition logic from the inter-vehicle type F / B control to the vehicle speed type F / B control, The operation of the vehicle speed type F / B control during the turning operation will be described.

In step S902 in FIG. 14, it is determined whether the turning operation is about to be started by detecting the steering angle θn. For the first time, if it is detected that the steering angle θn is not in the neutral position, the process proceeds to step S902 → step S960 → step S962 to set a flag TRN indicating that the vehicle is turning. In step S964, the inter-vehicle distance Dn at the time of entering the curve is stored in the register DST, and in step S966, the vehicle speed Vn at the time of entering the register VST.
Store in SPST. Then, in step S968, the timer TRNTMR indicating the turning time is incremented. Further, in step S969, the current steering angle θn is stored in the maximum steering angle register MAXθ. Once the flag TRN is set,
Unless the handle returns to the neutral position (θn = N),
Since it means that the vehicle is turning, step S9
02 → In step S960, the maximum steering angle MAXθ is updated (step S972) by determining whether the steering wheel steering angle θn has been further turned (step S970), and the turning time timer TRNTMR is incremented in step S974.

When it is confirmed that the steering angle has returned to the neutral position, step S902 → step S904 → step S
Proceeding to 906, the average acceleration / deceleration G during turning is calculated. G = (Vn-VSPST) / TRNTMR (22) Here, Vn in the above equation means the vehicle speed when the vehicle exits the curve. Therefore, G in equation (22)
Indicates how much the vehicle speed increased or decelerated during turning. G> 0 represents acceleration, and G <0 represents deceleration.

In step S908, the average acceleration / deceleration G _ij during turning is learned. This learning will be described. The driver's individuality should appear in the target vehicle speed TGV during turning. If the target vehicle speed is set to the learned vehicle speed at the start of turning, the vehicle speed is rather greatly changed and the discomfort is amplified. Therefore, as shown in FIG. 18, the target vehicle speed TGV at the start of turning (when entering a curve) is set to the actual vehicle speed Vn at that time, and thereafter, the vehicle speed is gradually reduced toward the target vehicle speed. preferable. This means that the target acceleration / deceleration [G
_ij ] is preferred. This is because the driver's preference for acceleration / deceleration should change depending on the approach vehicle speed Vn and the maximum steering angle at the time of entering the curve. Therefore, in this system, the population for learning the target acceleration / deceleration G _ij is changed according to the vehicle speed VSPST at the time of approach and the maximum steering angle MAXθ during turning.

FIG. 19 shows the discrimination of the population for learning the acceleration / deceleration G. That is, in this system, the maximum steering angle MA
Divide Xθ into two groups, large and small, and approach vehicle speed VSPST into two groups, high speed and low speed. Then, as shown in FIG. 19, a small maximum steering angle MAXθ and a low approach vehicle speed VSP
ST population (represented by subscript (1, 1)), small maximum steering angle
Population of MAXθ and high-speed approach vehicle speed VSPST (subscript (1, 2)
, And a large maximum steering angle MAXθ and a low approach vehicle speed VSPST
The population of the population (represented by the subscript (2, 1)), the population of the large maximum steering angle MAX θ and the fast approaching vehicle speed VSPST (subscript of the subscript
For each of the four populations (represented by (2, 2)), the number c _ij of samples in the population and the acceleration / deceleration [G _ij ] are learned. That is, the learning of the number of samples c _ij is set to c _ij = c _ij +1 (23) every time the curve is _{exited, and} the learning of the acceleration / deceleration is [G _ij ] = (G _ij + G) / c _ij (24) ). If the acceleration / deceleration [G _ij ] is learned by changing the population for each steering angle MAXθ and each approaching vehicle speed VSPST, the [G _ij ] should reflect the driver's habit. . Then, if the learning number c _ij becomes sufficiently large, the learning accuracy should increase.

Next, the feedback control when the turning operation is started during the inter-vehicle type F / B control will be described according to the control procedure of FIGS. 9 to 11. Flag SET =
1, flag ISD = 1, flag FAIL = 0, flag VF = 0,
Since the flag TRN = 1, the control is step S501.
→ step S502 → step S520 → step S5
The sequence proceeds from 28 → step S540 → step S580. In step S580, the flag IST is checked. This flag IST
Is a flag for controlling the initial setting of the target vehicle speed to the approach vehicle speed Vn when the vehicle travels from straight running to turning running. Therefore, IST = 0 now, and step S
Proceeding to 588, the target vehicle speed TGV is set to the approach vehicle speed Vn.

TGV = Vn (25) In step S590, the flag IST is set to 1. In steps S592 to S606 (FIG. 11), vehicle speed type F / B control for the target vehicle speed is performed. Once the flag IST is set, control proceeds to step S58.
0 → proceeding to step S582, the number of learnings c _ij is checked.

While the number of times of learning is small (step S582
Is NO) is a vehicle speed type F / with the vehicle speed at the time of approach as the target vehicle speed.
B control is performed, but when learning is sufficiently performed (c
_ij > c _s ) is obtained by searching the maximum steering angle MAX θ at that time and the acceleration / deceleration [G _ij ] corresponding to the vehicle speed VSPST at the time of entry from FIG. 19 in step S584. And
The target vehicle speed TGV is decelerated according to TGV = TGV + [G _ij ] (26).

The target vehicle speed TGV set in this way
Should most closely match the driver's "habit" according to the steering angle θ at that time and the vehicle speed entering the curve. When vehicle speed type F / B control targeting such a target vehicle speed TGV is performed, the curve From the entry to the exit of the curve, the inter-vehicle type F /
The control shifts from the B control to the vehicle speed type F / B control without a feeling of discomfort, and thereafter, the vehicle speed type F / B control which does not cause a feeling of discomfort and which matches the "habit" of the driver is automatically performed. <Control at the time of signal deterioration> Disappearance determination of inter- vehicle signal During auto cruise by inter-vehicle type F / B control,
It is important to keep track of the distance to the vehicle ahead. Therefore, this system uses a radar sensor. However, on an actual road, the vehicle body makes a pitch movement, so the light and sound emitted from the sensor are excessively directed upward and downward, and the light (sound wave) emitted to the vehicle ahead is emitted.
May not arrive, or the reflected wave may not reach the sensor 10. A sensor that emits light or sound to the front to measure distance is vulnerable to rain and dust, and the signal disappears when it is exposed. Under such a signal loss, it is difficult to continue the inter-vehicle type F / B control. Therefore, this system detects a signal loss during the inter-vehicle type F / B control (inter-vehicle signal If the inter-vehicle disappearance flag VF = 1) indicating that the vehicle has disappeared or a sign that the sensor function is deteriorated is detected (flag FAIL = 1), the inter-vehicle type F / B
The control is switched to the vehicle speed type F / B control which is an auto cruise mode in which an inter-vehicle signal is unnecessary.

The control procedure for signal loss determination will be described with reference to FIG. In this control procedure, the inter-vehicle distance is measured as infinity or the actual inter-vehicle distance and the target inter-vehicle distance T
When the deviation from GD is measured as an uncontrollable distance, it is determined that the signal has disappeared (VF = 1). Step S
At 202, the LCKON flag indicating whether or not the target is captured is checked. The condition set by this flag LCKON is that the deviation between the target inter-vehicle distance TGD and the actual inter-vehicle distance Dn is not large.
That is, when | TGD-Dn | <Ds (27) is detected (step S572 in FIG. 11). Here, the constant Ds indicates a predetermined distance that enables the system to perform the inter-vehicle type F / B control. Therefore, the flag LCKON indicates whether the preceding vehicle is captured within the target inter-vehicle distance.

When the inter-vehicle distance does not indicate infinity,
It cannot be determined whether it is a false signal or a correct signal. Therefore, in FIG. 20, when the flag LCKON is not set (that is, the preceding vehicle is not captured), the disappearance determination is performed according to whether the distance signal indicates infinity, and the flag LCKON is set. (That is,
When the preceding vehicle is captured), the disappearance determination is performed based on the difference between the target vehicle and the actual vehicle.

When the flag LCKON is 0, that is, the inter-vehicle type F /
A case where B control is not performed will be described. In such a case, the previously measured inter-vehicle distance Dn-1 does not indicate infinity (NO in step S204), but the inter-vehicle distance Dn measured this time indicates infinity (step S208). YES in step S21.
At 0, the fact that the inter-vehicle signal has disappeared is stored (VF = 1).
On the contrary, if the inter-vehicle distance does not indicate infinity in either the previous measurement or the current measurement, the flag VF is reset in step S214.

Incidentally, as described above, the inter-vehicle signal D is likely to contain noise due to the pitch movement of the vehicle body. In other words, it may happen that the inter-vehicle distance is erroneously measured. It is not a good idea to determine the signal loss based on such a noisy inter-vehicle signal, immediately shift from the inter-vehicle type F / B control to the vehicle speed type F / B control, and remain in the vehicle speed type F / B control as it is. Therefore, in this system, the number of times the signal is lost is counted, and the inter-vehicle type F /
The control mode when shifting from the B control to the vehicle speed type F / B control is changed (step S528 in FIG. 9). The timer VT counts the number of times.

The condition counted by the timer VT is that the inter-vehicle distance is measured as infinity both last time and this time (step S20).
4, YES in S206) or when infinity is detected for the first time in this measurement (NO in step S204, YES in step S208). And this timer V
The condition that T further clears the flag VF is when the inter-vehicle signal does not indicate infinity over two or more consecutive measurements. In other words, the timer VT continues counting as long as the inter-vehicle signal continues to indicate infinity after it is detected that the inter-vehicle signal Dn has shown infinity for the first time. When the infinity is not shown twice consecutively, the timer VT and the flag VF are reset.

The case where the target capture flag LCKON is 1, that is, the case where the inter-vehicle type F / B control is performed will be described. The difference between the target inter-vehicle distance TGD and the previous actual inter-vehicle distance Dn-1 was not large (| TGD- in step S218).
If the difference between the Dn−1 | ≦ A) and the inter-vehicle distance Dn measured this time is large (YES in step S222), it is stored in step S228 that the inter-vehicle signal has disappeared (VF).
= 1). On the contrary, if the difference in the inter-vehicle distance is not large in the previous measurement and the current measurement, step S224
The flag VF is reset with. The condition for the timer VT to count the signal loss is that the difference between the vehicle distances is measured to be large in the previous time and this time (YE in steps S218 and S232).
S) or when it is detected that the difference in the inter-vehicle distance is large for the first time in this measurement (NO in step S218, YES in step S222). The condition for the timer VT to further clear the flag VF is that there is no significant difference in the inter-vehicle distance over two or more consecutive measurements. Detection of Deterioration of Sensor Function FIG. 20 illustrates a logic for detecting that the sensor is soiled due to rain or the like and its function is deteriorated.

In step S302, it is checked whether the wiper 61 is operating. If the wiper is on, it is raining and the sensor function is definitely considered to have deteriorated, and the flag FAIL is set in step S320. Steps S304 and thereafter are at a rate at which the sensor 10 loses a signal when the wiper is not operating (second
It is to judge whether VF = 1) in FIG. SMPTMR in step S304 defines the time interval for making the above determination. That is, when the wiper is not operating, the timer SMPTMR is counted up in step S306 to determine the sampling time. Then, the signal loss flag VF
The time CNT set by is counted in step S310. Sampling time (B minutes) has passed (step S30
If YES in step S4, it is determined in step S312 at what time ratio the signal disappeared within B minutes.

Loss rate = CNT / B (28) In steps S314 and S316, the counter CNT and the timer SMPTMR are reset in order to calculate the loss rate again. The loss rate exceeds C% (step S
318), it is determined that the sensor has deteriorated, and the flag FAIL is set to 1 in step S320.

As described above, in this system, if the signal disappearance state is detected even for a short time due to the pitch motion of the vehicle body, for example, it is stored in the flag VF, and the disappearance time is the inter-vehicle disappearance timer VT. Memorized in. Further, if such a disappearance state exceeds a certain rate, it is determined that the sensor function is deteriorated and stored in the flag FAIL. Operation or loss of signal states of the D-type F / B control (VF = 1) and sensor deterioration state (FA
In IL = 1), how the inter-vehicle type F / B control of this system is affected will be described with reference to the flowcharts of FIGS. 9 to 11. According to the control procedure of this flowchart, the inter-vehicle F / B control is shifted to the vehicle speed F / B control when there is a possibility that the sensor signal is incorrect. Then, depending on the length of the signal loss time, the vehicle speed type F
The control when shifting to the / B control is slightly different.

When it is determined that the sensor function is deteriorated, that is, when the flag FAIL = 1, the process proceeds from step S520 to step S522 and is saved when the SET switch, RESUME switch or COAST switch is turned on. Compare the Oita set vehicle speed MTGV with the current actual vehicle speed Vn. There is a difference of 10 km / h or more between the two vehicle speeds (step S52).
If YES in step 2), the set vehicle speed MT is set in step S524.
GV is the target vehicle speed.

TGV = MTGV (29) If there is no opening of 10 km / h or more, step S5
At 26, TGV = Vn (30) in order to set the current vehicle speed to the target vehicle speed. Then, in step S508, the inter-vehicle distance type F
The integral variable E _dI for / B control and the integral variable E _vI for vehicle speed type F / B control are reset. Then, step S508 →
Step S510 → Step S512 → Step S51
The sequence proceeds from 4 → step S516 → step S518 to set various flags for the vehicle speed type F / B control mode.

Even when the sensor is not detected to be deteriorated (NO in step S520), the signal disappearance time VT is longer than the time Ts (YES in step S530),
Proceeding to step S522, the control is the same as when the sensor is deteriorated. When the signal loss time is short, that is, VT ≦
If Ts (NO in step S530), step S5
Proceed to 32. In step S532, the flag ISF is checked. This flag ISF indicates that the vehicle speed type F / B control is "temporarily" performed due to temporary signal loss. Therefore, it is determined to be NO in step S532, the target vehicle speed TGV is set to the current vehicle speed Vn in step S534, and the flag ISF is set to control in step S536.
In step S538, the integral variable E _vI is reset to 0 in order to perform the vehicle speed type F / B control. However,
The integral variable E _vI for the inter-vehicle type F / B control is not reset.

The fact that the disappearance time VT is shorter than Ts in step S530 means a temporary disappearance of the signal (for example, disappearance due to the pitch movement of the vehicle body). When this happens,
The loss of signal condition is expected to recover soon. Therefore, the time for vehicle speed type F / B control depending on the disappearance state will be short. Then, if the signal disappearance state is recovered for a short time, it is desirable to return from the vehicle speed type F / B control to the inter-vehicle type F / B control. If there is a short-time signal loss (NO in step S530), the process proceeds to step S508 to reset the integration variable E _dI for the inter-vehicle type F / B control. Even if it returns to the inter-vehicle type F / B control in a short time, the previous inter-vehicle type F
Since the integral variable E _dI accumulated during the period of the / B control is lost in step S508, the transition of the control of the inter-vehicle type F / B control → the vehicle speed type F / B control → the inter-vehicle type F / B control occurs. Continuity is lost and control becomes jerky. In the present system, as described above, regarding signal loss for a short time, the process does not proceed to step S508 but to step S5.
Since the integration variable E _dI is not reset at 38, continuity is ensured in the control, and smooth control can be expected when returning to the inter-vehicle type F / B control.

The case where the signal loss time gradually increases will be described with reference to FIG. During the inter-vehicle type F / B control, the signal disappears at time t ₁ (however, VT ≦ Ts)
_{Is detected} , the integration variable E _vI for the vehicle speed type F / B control is reset, but the E _dI for the inter-vehicle type F / B control is saved. If the signal disappearance state continues and VT = Ts at time t ₂ as shown in FIG. 22, in step S508, an integral variable E _vI for vehicle speed type F / B control is _obtained.
And E _dI for inter-vehicle type F / B control are also reset. Therefore, unlike FIG. 22, if the signal disappearance state is canceled before time t ₂ , the E _dI for the inter-vehicle type F / B control remains stored, and the flag ISD also remains set. Go from step S544 to step S562,
It is possible to smoothly return to the inter-vehicle type F / B control. <Effects of the Embodiment> According to the embodiments described above, I : the “preference” and “habit” of the driver with respect to the inter-vehicle distance during curve traveling or acceleration traveling without inter-vehicle F / B control Since the vehicle is learning (step S928 in FIG. 15), during the inter-vehicle type F / B control traveling,
The auto cruise is realized by the inter-vehicle distance D _ij that does not make the driver feel uncomfortable. I-1 : Further, since the target inter-vehicle distance D _ij is learned separately for each vehicle speed band (Fig. 16), the inter-vehicle distance setting D _ij can be performed with high accuracy. I-2 : Since the target inter-vehicle distance D _ij is learned separately for each band of acceleration / deceleration G (Fig. 16), the inter-vehicle distance setting D _ij
Can be performed with high accuracy. I-3 : The learning number _{nij in the} equation (20) is incremented every time the acceleration / deceleration operation is performed. That is, frequent acceleration / deceleration operations increase the value of the learning count _nij . Therefore,
In Equation (21), the learning inter-vehicle distance [D _ij ] is set to be small. This is because it may be determined that the driver wants a shorter inter-vehicle distance when the vehicle is frequently driven by the acceleration / deceleration operation. II : In the case where the capture of the preceding vehicle is lost during the inter-vehicle type F / B control traveling (YES in step S528), or when it can be determined that the accuracy of the inter-vehicle distance sensor is deteriorated (YES in step S520) It is possible to continuously shift from the inter-vehicle F / B control traveling until then to the vehicle speed F / B control traveling. II-1 : In particular, during the inter-vehicle type F / B control operation, when the capture of the preceding vehicle is lost (YES in step S528) or when it can be determined that the accuracy of the inter-vehicle distance sensor is deteriorated (step S520). YES), Ts
During the time (NO in step S530), the vehicle speed type F / B control is "temporarily" performed. This "temporary" vehicle speed type F
Depending on the shift to the / B control, the inter-vehicle type F / B up to that time
Since the integral variable E _dI in the controlled traveling is stored (step S538), if the signal disappearance state is eliminated in a short time (NO in step S528), the integral variable E of the previous inter-vehicle type F / B control is By using _dI , the "gap" between the previous inter-vehicle type F / B control and the inter-vehicle type F / B control to be performed is reduced, and the inter-vehicle type F / B control is performed.
You can smoothly return to control. II-2 : Step S526 and Step S534
At the vehicle speed type F / B,
Since the target vehicle speed for control is set,
It is possible to mitigate large fluctuations in vehicle speed when shifting from / B control to vehicle speed type F / B control. II-3 : Further, in step S530, if the lost state is not recovered even after a certain period of time, step S530.
Returning to 508, the integration variables E _dI and E _vI are reset. This is because the running environment may change when a large amount of time has passed, and it is not preferable to hold the control variable for a long time in order to maintain the reliability of control. III : In the above embodiment, the vehicle speed type F /
The B control is performed, and the inter-vehicle type F / B control is performed while traveling on a curve other than the curve (step S586 in FIG. 10). Then, by using the acceleration / deceleration G _ij learned in the curve traveling up to that time, the target vehicle speed TG during the curve traveling
V is reached (step S5 in FIG. 10).
86). III-1 : The acceleration / deceleration G _ij is learned based on the vehicle speed VSPST when entering the curve and the vehicle speed Vn when leaving the curve (step S906). IV-1 : The SET switch of this embodiment is used only for setting the target vehicle speed (step S13 in FIG. 3).
Instead of 4), it can also be used when setting the target inter-vehicle distance (step S138 in FIG. 3). IV-2 : Not only the target vehicle speed can be continuously increased or decreased by continuously pressing the SET switch (step S118 in FIG. 4), but also the target inter-vehicle distance can be continuously decreased or increased. Can (third
The step S116) in the figure can be performed. Increasing (decreasing) the target vehicle speed and decreasing (increasing) the target inter-vehicle distance do not make the driver feel uncomfortable in operation. <Modification> The present invention can be variously modified without departing from the spirit thereof. First Modification In the above-described embodiment, when the preceding vehicle disappears while the inter-vehicle F / B control is being executed, the inter-vehicle F / B control is changed to the vehicle speed F / B.
When the control signal shifts to the control but the inter-vehicle signal disappears for a short time, the integral variable E _vI for the vehicle speed type F / B control is reset, but the signal should recover within the short time. Therefore, the integration variable E _dI for the inter-vehicle distance F / B control accumulated during the inter-vehicle distance F / B control period up to that point is not reset (see step S538 in FIG. 9).

The first modified example to be described below is a further development of the holding operation of the integral variable.
In the transition of the control between the control and the inter-vehicle type F / B control, the integral variable calculated during the period of one control is taken over by the other control. The control variable m for the throttle opening TG in the first modification is defined as follows. That is, for the D-type F / B _{control, m = m + K dI ×} (D n -TGD) + K dP × (D n -D n-1) -K dD × (2D n-2 -D n-1 -D _n) ... (31) for the S-type F / B control _{is, m = m + K vI ×} (D n -TGV n) + K vP × {(TGV n -TGV n-1) - (V n -V n-1) _{} -K vD × (V n +} V n-2 -2V n-1) ... (32) (31) m is common in equation (32) below. Therefore, for example, when the vehicle speed type F / B control is performed while the vehicle type F / B control is being performed, the value of the integral variable m during the vehicle type F / B control is succeeded to the vehicle speed type F / B control. Be done.

23 to 25 are flow charts showing the procedure of feedback control in the first modification. In many respects, the control procedure of FIGS. 23-25 is similar to the control procedure of FIGS. 9-11 of the previous embodiment.
However, in order to carry over the above integrated value,
In the control procedure of the first modification, step S53 of FIG.
6, the step S552 of FIG.
In step S596 ′ in the figure, the vehicle speed type F / B control is calculated based on the equation (32), and in step S566 ′, the inter-vehicle type F / B control is calculated based on the equation (31). . Also, step S59 in FIG.
2, 594, step S562 and step S564 are unnecessary.

In step S508 ', the control amount m is set to 0.
Has been reset to. This is because when the vehicle speed type F / B control is performed when the distance between the vehicle type F / B control is impossible in step S504, the vehicle type F / B
This is because it is meaningless to continue subtracting the control amount m in the B control. For this reason, when the inter-vehicle signal is lost and the inter-vehicle F / B control is switched to the vehicle speed F / B control, the control amount m during the inter-vehicle F / B control period is equal to the vehicle speed F. / B
Since control should be taken over, unlike the control procedure of FIG. 9, steps S524 to S526 are also performed.
From step S508 'to step S508'
I proceed to 510 and try not to clear m. Effects of First Modified Example According to the first modified example described above, since the control amount m is succeeded, the control change between the vehicle speed type F / B control and the inter-vehicle type F / B control becomes smooth, Do not make the driver feel uncomfortable. Also in the above embodiment, step S538 in FIG.
In the case where the vehicle speed type F / B control is temporarily _transited to, the integral variable E _vI was stored, but in this modified example, the storage is further thorough. Second Modification This second modification relates to the learning logic of the acceleration / deceleration during turning, and is shown in FIG. What is greatly different from the learning control procedure shown in FIGS. 14 to 15 is that
The learning method is different, and the logic for learning the "habit" of the driver's acceleration during acceleration is not incorporated. However, a flag TRN indicating that the line is in the middle or a timer TRNTM that counts the time during turning
For R, acceleration / deceleration G _ij, etc., the same symbols as the variables in FIG. 14 and the like are used.

In step S400 of FIG. 26, it is determined whether the steering angle is in the neutral position (θn = N). Since θn ≠ N when the turning is started, step S4
20 → Go to step S422 to set the flag TRN, and further, the inter-vehicle distance Dn with the preceding vehicle at that time is stored in the register DST (step S424), and the vehicle speed Vn is saved in the vehicle speed register VSPST during corner entry (step S426). The steering angle θn is saved in the maximum steering register MAXθ (step S428). Then, in step S430, the timer TRNTMR for storing the turning time is counted up.
The maximum steering angle MA is set in steps S432 and S434.
This is the Xθ update routine.

Unless the steering wheel steering angle θ returns to the neutral position, the timer TRNTMR is counted up in step S430. When the vehicle passes through the curve or corner and returns to the neutral position, in step S404, the acceleration / deceleration data G _ij learned up to that time is set to the vehicle speed VSPST at the time of entry and the maximum steering angle MAXθ during turning. Search for and read the corresponding one.

In steps S406 and S408, the inter-vehicle distance DST when entering the curve and the inter-vehicle distance Dn when leaving the curve are compared. Assuming that Ds1 is a positive constant, in step S406, DST-Dn> Ds1 (33) That is, when the distance between vehicles is smaller when the vehicle leaves the lower part than when the vehicle enters the curve, , It is the driver's "preference" (or "habit") that keeps the distance between vehicles short.
And [G _ij ] = [G _ij ] + ΔG (34) in step S412. Since ΔG is a positive constant, the equation (34) has a learning effect of increasing the acceleration / deceleration [G _ij ]. On the other hand, in step S408, DST-Dn <Ds1 (35) That is, when the vehicle distance when leaving the lower portion is larger than when the vehicle enters the curve, the driver determines that "Preferences" (or "habits") to keep for a long time
And [G _ij ] = [G _ij ] −ΔG (36) in step S410.

Acceleration / deceleration [G _ij ] of equations (34) and (36)
Is the determination of the target throttle opening in FIG. 10 (step S5
86), that is, TGV = TGV + [G _ij ]. Therefore, also in this second modified example, the target throttle opening degree is determined by reflecting the acceleration / deceleration [G _ij ] that was previously learned. In other words,
Also in this second modified example, the throttle opening TGV increased or decreased corresponding to [G _ij ] can be obtained by the control procedure of FIG. 10, so that the vehicle speed may be increased or decreased during the curve running. The vehicle distance is adjusted to match the driver's preference as a result. Effects of Second Modification According to the control procedure of FIG. 26, the learning procedure counter c _ij is not required as compared with the control procedures of FIGS. 14 and 15, so that the control procedure is simplified. The effect is obtained. Third Modified Example This third modified example aims at performing appropriate control separately for a case where there is an interrupting vehicle ahead and a case where a road surface or a guardrail is erroneously determined to be a forward vehicle. The reason why such an erroneous determination occurs will be described with reference to FIGS. 29 and 30.

When the vehicle is traveling along a curve, the steeper the curve, the more the guardrail comes to the front of the vehicle in many cases. Since the inter-vehicle distance sensor 10 uses the reflected wave, the reflected wave from the guardrail is erroneously recognized as the reflected wave from the vehicle ahead as shown in FIG. When the vehicle body makes a pitch motion as shown in the first place, the reflected wave from the road surface is erroneously recognized as the reflected wave from the vehicle ahead. Therefore, in the third modified example, when the distance measured by the sensor to the front vehicle (presumably a front object) is shorter than the target inter-vehicle distance TGD for a predetermined time (T _ss ), it is erroneously recognized. Instead, judge that there was an interruption vehicle ahead. In such a case, the vehicle speed type F / B control is quickly changed to the inter-vehicle type F / B control.

In order to perform such control, this third
In the control procedure according to the modification, the steps S218 to S232 in FIG. 20 of the above embodiment are changed to the control procedure in FIG. Further, a part of FIG. 9 is modified as shown in FIG. The control procedure of FIG. 27 calculates the deviation between the target inter-vehicle distance TGD and the distance Dn to the front object at that time, compares the deviation with the threshold value A, and stores the result in the inter-vehicle distance flag DF. is there. That is, DF = 0 → the target inter-vehicle distance TGD matches the actual inter-vehicle distance Dn DF = 1 → The actual inter-vehicle distance Dn is longer than the target inter-vehicle distance TGD DF = 2 → The actual inter-vehicle distance Dn is shorter than the target inter-vehicle distance TGD. This flag DF and step S212 in FIG.
On the basis of the signal disappearance time VT counted in step 2, the vehicle interrupt and the erroneous recognition of the vehicle ahead are distinguished by the control procedure of FIG.

That is, the value of the flag DF is checked in steps S1100 and S1102 in FIG. DF =
0, that is, if the preceding vehicle is within the target inter-vehicle distance TGD, the process proceeds to step S540, and the same inter-vehicle type F / B control as in the embodiment (FIG. 10) is performed. If DF = 1, in step S1104, the value stored in the signal loss timer VT is compared with a predetermined threshold value T _SL . Here, VT is step S1011, step S1012, step S102.
5, The time counted in step S1035, which is the time when the actual vehicle distance is longer or shorter than the target vehicle distance, is maintained. This threshold T _SL is the ninth
If it is substantially the same as T _S in step S530 in the figure, that is, if VT> T _SL , the process proceeds to step S522, and "complete" from the inter-vehicle type F / B control to the vehicle speed type F / B control. The transition will be made, and if VT ≦ T _SL , the process will proceed to step S532, and the “temporary” transition from the inter-vehicle type F / B control to the vehicle speed type F / B control will be performed.
"Complete" transition and "temporary" to vehicle speed type F / B control
The difference from the transition has already been described in the above embodiment. That is, when the actual inter-vehicle distance Dn is longer than the target inter-vehicle distance, the control shifts to the vehicle speed type F / B control, and the reason is that there is little meaning to continue the inter-vehicle type F / B control. On the other hand, if DF = 2, step S110
In step 6, the disappearance time VT is compared with the threshold T _SS . Even if the actual inter-vehicle distance Dn is shorter than the target inter-vehicle distance (DF =
2) In other words, even if there is something that seems to be a vehicle ahead at a short distance, it was detected that the time VT at which the forward object was closer than the target inter-vehicle distance was shorter than the threshold time T _SS , which means that it was the pitch. Since it is highly likely that the cause is movement or curve running, the process is not limited to the inter-vehicle type F / B control, and the process proceeds to step S1106 to shift to the "temporary" vehicle speed type F / B control. On the other hand, if there is a vehicle-like object in the front of the short distance (DF = 2), and if the time VT during which the object exists in the front of the short distance is longer than the threshold value T _SS , the object is a front interrupt vehicle. Then, the process proceeds to step S540 to continue the inter-vehicle type F / B control. That is, the inter-vehicle type F / B control is performed with the interrupting vehicle as the target. Effect of the Third Embodiment According to the third modified example, not only the front interrupt vehicle can be accurately determined, but also the target vehicle of the inter-vehicle type F / B control is changed from the front vehicle to the interrupt vehicle thereafter. , The inter-vehicle type F / B control can be continued.

[0077]

As described above, the vehicle speed control system of the present invention comprises a distance sensor for detecting the distance to the front object, and means for calculating a predetermined control variable based on the output signal from the sensor. An inter-vehicle distance type auto-cruise means for maintaining the inter-vehicle distance to the preceding vehicle at a predetermined target inter-vehicle distance based on the calculated control variable, and means for estimating whether or not the distance sensor can capture the preceding vehicle And a holding means for stopping the operation of the inter-vehicle distance type auto-cruise means when it is estimated that the vehicle ahead cannot be captured, and holding means for holding the value of the control variable. Characterize.

Therefore, when the front vehicle disappears during the inter-vehicle type F / B control auto cruise, there is a large change in the target vehicle speed when the inter-vehicle type F / B control is changed to the vehicle speed type F / B control. Therefore, the vehicle speed control device that does not make the driver feel uncomfortable is proposed. According to a preferred aspect of the present invention, when the vehicle speed is maintained at a predetermined vehicle speed when it is estimated that the vehicle ahead cannot be captured, the inter-vehicle type F / B is changed to the vehicle type F / B. A smooth transition in vehicle speed can be secured.

According to a preferred aspect of the present invention, the integrated value of the deviation can be held for a predetermined time, so that the reliability of the control can be ensured even if the front passenger compartment may extend for a long time. According to a preferred aspect of the present invention, when the preceding vehicle returns to the state where it can be captured again, it is possible to smoothly shift to the inter-vehicle type F / B control.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an automatic cruise system according to a preferred embodiment of the present invention.

FIG. 2 is a functional block diagram showing an operation of the automatic cruise system according to the embodiment.

FIG. 3 is a flowchart illustrating a main routine of the control procedure of the embodiment.

FIG. 4 is a flowchart illustrating a main routine of the control procedure of the embodiment.

FIG. 5 is a flowchart illustrating a main routine of the control procedure of the embodiment.

FIG. 6 is a flowchart illustrating a main routine of the control procedure of the embodiment.

FIG. 7: Throttle opening TG corresponding to accelerator opening α
The graph figure which shows the relationship with.

FIG. 8 shows a vehicle speed Vn and a constant acceleration a with respect to the vehicle speed Vn.
The graph which shows the relationship with the throttle opening TG such that

FIG. 9 is a flowchart showing a feedback control procedure of the embodiment.

FIG. 10 is a flowchart showing a feedback control procedure of the embodiment.

FIG. 11 is a flowchart showing a feedback control procedure of the embodiment.

FIG. 12 is a vehicle speed type F / F according to the control procedure of FIGS.
The timing chart explaining operation | movement when shifting to B-type F / B control from B control.

FIG. 13 is a vehicle speed type F / F according to the control procedure of FIGS.
The timing chart explaining the change of the control variable En and integral variable _EvI in B control.

FIG. 14 is a flowchart showing a control procedure for learning in the embodiment.

FIG. 15 is a flowchart showing a control procedure for learning in the embodiment.

FIG. 16 is a diagram illustrating the principle of learning a target inter-vehicle distance.

FIG. 17 is a diagram illustrating the principle of learning a target inter-vehicle distance.

FIG. 18 is a diagram illustrating the principle of learning a target vehicle speed when turning.

FIG. 19 is a diagram illustrating a principle of learning a target vehicle speed when turning.

FIG. 20 is a flowchart of a control procedure for detecting a signal loss and a preceding vehicle loss.

FIG. 21 is a flowchart showing a control procedure for detecting performance deterioration of a distance sensor.

FIG. 22 is a timing chart for explaining the transition from the inter-vehicle type F / B control to the vehicle speed type F / B control when a signal disappears.

FIG. 23 is a flowchart showing a control procedure according to a first modification.

FIG. 24 is a flowchart showing a control procedure according to a first modification.

FIG. 25 is a flowchart showing a control procedure according to a first modification.

FIG. 26 is a flowchart showing a control procedure according to a second modification.

FIG. 27 is a flowchart showing a control procedure according to a third modification.

FIG. 28 is a flowchart showing a control procedure according to a third modification.

FIG. 29 is a diagram for explaining the reason why a target is likely to be lost during curve traveling.

FIG. 30 is a diagram for explaining the reason why a target tends to disappear when the vehicle body makes a pitch motion.

Claims (8)

[Claims] 1. A distance sensor for detecting a distance to a front object, a means for calculating a predetermined control variable on the basis of an output signal from the sensor, and an inter-vehicle distance to a front vehicle as a calculated control variable. Based on the inter-vehicle distance type auto-cruise means for maintaining a predetermined target inter-vehicle distance, means for estimating whether or not the distance sensor can capture a front vehicle, it is estimated that the front vehicle is not in a captureable state. In this case, the vehicle speed control device further comprises a holding means for stopping the operation of the inter-vehicle distance type auto-cruise means and holding the value of the control variable. 2. The vehicle speed control device according to claim 1, wherein the estimating means estimates that a vehicle ahead cannot be captured when a signal from the sensor indicates infinity for a predetermined time. An automobile speed control device characterized by: 3. The vehicle speed control device according to claim 1, wherein the estimating means is capable of executing an inter-vehicle distance type auto cruise when the inter-vehicle distance to the preceding vehicle obtained based on the signal from the sensor. A vehicle speed control device, which estimates that a vehicle ahead cannot be captured when a vehicle is not in a distance for a predetermined time. 4. The vehicle speed control device according to claim 1, wherein the estimating means estimates that the vehicle ahead cannot be captured because the wiper has operated. 5. The vehicle speed control device according to claim 1, wherein the inter-vehicle distance type auto-cruise means controls the vehicle speed based on an integral of a deviation between a target inter-vehicle distance and a detected inter-vehicle distance detected by the sensor. The vehicle speed control device is characterized in that the inter-vehicle distance is converged to the target inter-vehicle distance, and the holding unit holds the deviation integral. 6. The vehicle speed control device according to claim 1, further comprising means for maintaining the vehicle speed at a predetermined vehicle speed when the estimating means estimates that the vehicle ahead cannot be captured. A vehicle speed control device characterized by: 7. The vehicle speed control device according to claim 1, wherein the holding means holds the integrated value of the deviation for a predetermined time. 8. The vehicle speed control device according to claim 1, wherein the distance sensor estimates whether or not the distance vehicle has returned to a state in which a preceding vehicle can be captured again, and the vehicle speed when it is estimated that the vehicle has returned. The type F / B automatic cruise means is stopped, and the vehicle type F
/ B The value of the control variable of the auto cruise means is set to the inter-vehicle type F / B.
A vehicle speed control device comprising means for transmitting to an auto cruise means.