JP2000043607A - Traveling control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give no sense of unease to a drive during deceleration by setting an auxiliary target deceleration speed in the case of obtaining the target deceleration speed to a calculated target acceleration and deceleration speed to perform deceleration. SOLUTION: A controller 10 is provided with an operation lever 13 for directing the traveling control such as constant speed traveling and follow-up traveling to the preceding vehicle. A throttle device 21 is adapted to vary the engine output by varying a throttle opening through an output interface from the CPU, and at the time of controlling the distance between cars, CPU gives output to an automatic brake device 22 for operating an automatic brake to the wheels. The target deceleration speed operation is performed to calculate the target deceleration. After the target deceleration is obtained, deceleration is performed to reach the target deceleration speed from the current car speed. When deceleration is suddenly performed, a sense of unease is given to a driver. Then, this device sets an auxiliary target deceleration speed, thereby gradually controlling the deceleration to gradually reach the target deceleration speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a travel control device capable of following a vehicle while maintaining an appropriate distance between the vehicle and a preceding vehicle.

[0002]

2. Description of the Related Art Heretofore, there has been known a vehicle in which speed is adjusted between a host vehicle and a preceding vehicle so as to follow the vehicle so that the inter-vehicle distance is constant. When performing this control, the control amount calculation of the inter-vehicle distance control includes, as shown in JP-A-3-213438, a preset target inter-vehicle distance,
A driving force (also referred to as a target acceleration / deceleration) required to maintain a target inter-vehicle distance using an actually measured inter-vehicle distance and a relative speed between the own vehicle and a preceding vehicle obtained from a time change of the inter-vehicle distance measurement value. Is calculated by the following calculation formula.

In this case, the driving force is: driving force = K1 × (target inter-vehicle distance−inter-vehicle distance) + K2 × relative speed (K1, K
2: proportional constant), and a method is adopted in which if the driving force is positive, throttle control is performed, and if the driving force is negative, brake control is performed.

[0004]

However, although the driving force is calculated from the above equation, the following problem occurs when there is an interrupted vehicle during inter-vehicle distance control with the preceding vehicle. For example, (a) when the vehicle travels at 100 km / h and the distance to the preceding vehicle is 55 m, when the interrupting vehicle suddenly enters 40 m before the vehicle, and (b) when the vehicle enters 100 km / h.
/ H, and the inter-vehicle distance is 40m, and the interrupted vehicle suddenly enters 25m before (in this case,
(A) and the relative speed of the preceding vehicle is the same)
The result of the driving force calculation is the same.

That is, since the relative speeds are the same, the target inter-vehicle distance-actual inter-vehicle distance = 15 m and the driving force are the same, but in actuality, (b) is more effective than (a).
The driver feels anxiety because the time (inter-vehicle time) required to reach the position where the preceding vehicle exists at the current traveling speed is short.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a travel control device that keeps a proper inter-vehicle distance and performs following travel without giving a driver anxiety during deceleration. Is a technical issue.

[0007]

Technical means taken to solve the above-mentioned problems include a vehicle speed sensor for detecting the speed of a vehicle, an inter-vehicle distance sensor for detecting an inter-vehicle distance to a preceding vehicle, and a vehicle speed sensor. And a controller that obtains the current inter-vehicle distance from the preceding vehicle, the target inter-vehicle distance, and the relative speed based on information from the inter-vehicle distance sensor, calculates a target acceleration / deceleration, and adjusts the vehicle speed adjustment device. When deceleration is performed by obtaining a target deceleration with respect to the set target acceleration / deceleration, an auxiliary target deceleration is set.

With the above configuration, when deceleration is performed by obtaining the target deceleration from the calculated target acceleration / deceleration, the auxiliary target deceleration is set, so that the auxiliary target deceleration is gradually increased until the vehicle reaches the target deceleration. In such a case, it is possible to prevent a sudden deceleration to the target deceleration from occurring, and to prevent the driver from feeling uneasy during the deceleration.

In this case, if the auxiliary target deceleration has a gradient with respect to the time required to reach the target deceleration,
It is possible to make a change by an appropriate gradient according to the time until the target deceleration is reached.

The gradient of the auxiliary target deceleration is determined by the inter-vehicle time (the time until the vehicle reaches the position of the preceding vehicle at the current traveling speed). If the setting is made abruptly, the setting according to the inter-vehicle time becomes possible, and it is possible to prevent the driver from feeling uneasy.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a system configuration diagram of the travel control device 1. The controller 10 that performs travel control is supplied with power from a battery via an ignition switch (IG SW), and an operation lever that instructs the controller 10 to perform travel control such as constant-speed travel and follow-up travel with respect to a preceding vehicle. A system switch (switch) 5 for operating the travel control device 1, an inter-vehicle distance sensor 6 for detecting an inter-vehicle distance to a preceding vehicle, a vehicle speed sensor 7 for detecting a vehicle speed, and a brake switch for detecting a driver's braking operation are provided. 8. Set by driver's switch operation
A cruise switch 9 for switching between the resume and cancel states and operating the speed control is input. Signals from these sensors 6 and 7 and switches 5, 8 and 9 are taken into a CPU that controls the control via an input interface inside the controller. A throttle device 21 that varies the engine output by varying the throttle opening through the output interface from the CPU;
In addition, during the inter-vehicle distance control, an output is provided to an automatic brake device 22 that operates an automatic brake for the wheels.

In this case, as a sensor for detecting an inter-vehicle distance, image processing by a camera, an ultrasonic sensor, a millimeter-wave radar, a laser radar, or the like can be used. Here, a laser radar is used. As the vehicle speed sensor 7 for detecting the vehicle speed, a normally used vehicle speed sensor provided at the output of the automatic transmission or a wheel speed sensor provided at least on one or more wheels for detecting the rotation of the wheels is provided. Can be used. Further, as an engine output adjusting device that performs inter-vehicle distance control and constant speed control, a throttle valve actuator that adjusts the engine output by driving a main throttle or a sub-throttle valve is used. A pressure control valve (such as a solenoid valve) provided between the pressure supply source and the wheel cylinder so that the brake pressure is applied to the wheel cylinder is used here.

The brake device 22 only needs to decelerate the vehicle, and the vehicle may be decelerated by an exhaust brake, such as a normally used hydro or vacuum brake.

Next, the processing of the controller shown in FIG. 2 will be described.

When the ignition switch (IG SW) is turned on and power is supplied from the battery to the controller 10, the controller 10 executes the control flowchart shown in FIG. In step S101 of FIG. 2, initial processing is performed first. In the initial processing, after the ROM and RAM in the controller are checked, initial values are set in the necessary memory of the RAM, and it is checked whether the system operates normally. In the next step S102, it is checked whether the system SW5 has been turned on. Here, if the system SW5 is not turned on (there is no request for traveling control), the process proceeds to step S.
Returning to step 102, the system waits until the driver requests driving control.
If 5 is turned on, step S103 of the speed control process
Execute the following. In step S103, an inter-vehicle distance is input. The inter-vehicle distance input is obtained by calculating the inter-vehicle distance data detected by the laser radar from the inter-vehicle distance sensor 6 as inter-vehicle distance data by an inter-vehicle distance controller provided in the inter-vehicle distance sensor, and then the data of the inter-vehicle distance with the preceding vehicle is transmitted to the communication line. Controller 10 by serial communication via
Is stored in the required memory as the inter-vehicle distance L from the preceding vehicle by the CPU.

In step S104, a vehicle speed is input. The vehicle speed input here is to input the vehicle speed of the own vehicle. For example, the average wheel speed of the wheel speeds provided on the wheels or the wheel speed of the wheel where no slip occurs is stored in a necessary memory as the vehicle speed V. . In step S105, a relative speed calculation is performed. In the relative speed calculation, the relative speed Vr is calculated by differentiating the input inter-vehicle distance L with respect to time. In the next step S106, an inter-vehicle time is calculated.
The inter-vehicle time indicates how long it takes to reach the position of the preceding vehicle at the current vehicle speed, and the inter-vehicle time TL is obtained from the inter-vehicle distance L / vehicle speed V.

In step S107, the state of the cruise SW9 is checked. The cruise SW 9 is attached to the back of the steering wheel in the same manner as the operation lever of the direction indicator, and is provided separately from the operation lever of the direction indicator. This cruise SW9
Can be switched stepwise by operation of the driver. Specifically, the operation lever 1 for instructing the traveling control
When the driver moves the driver 3 downward, the vehicle speed of the current running vehicle is set (set state). In addition, when the operation lever 13 is moved upward, the vehicle speed is set to the vehicle speed before the speed control was released (the vehicle speed set before) (resume state), and when the operation lever 13 is moved toward the near side. The speed control is released (canceled). On the other hand, when the operation lever 13 is pulled upward, the inter-vehicle distance to the preceding vehicle can be shortened, and the setting can be performed according to the driver's preference. Step S
At 107, the cruise SW 9 is operated by the driver to check whether the cruise SW 9 is set or resumed. Here, if the vehicle is not in the set or resume state, the process returns to step S102. If the vehicle is in the set or resume state, the target inter-vehicle time is set in step S108. In the target inter-vehicle time setting, the inter-vehicle time TL obtained from the vehicle speed and the inter-vehicle distance when the driver operates the cruise SW 9 is the target inter-vehicle time TL. Therefore, the target inter-vehicle time TL can be arbitrarily set according to the driver's preference.

In step S109, a target inter-vehicle distance is calculated. Here, the target inter-vehicle distance LT is the cruise S
It is calculated by the product of the target inter-vehicle time TLS and the vehicle speed V when W9 is operated (LT = TLS.V). Here, when the target inter-vehicle distance is calculated, the inter-vehicle time is obtained. As shown in FIG. 3, the target inter-vehicle distance is a vehicle speed V1 (40 Km /
h), target inter-vehicle distance L for V2 (100 km / h)
1 (2 m), L2 (16.7 m), L3 (22.2)
m), L4 (27.8 m), L5 (41.7 m), L6
(55.6 m) and L7 (69.5 m), a map is used with the inter-vehicle time (1 sec to 2 sec) as a parameter, and the inter-vehicle time is set from this map.
Thereafter, a target deceleration gradient is set in step S110, and the target deceleration gradient is set to a deceleration gradient corresponding to the inter-vehicle time obtained from FIG. 3, for example, from the characteristic diagram of inter-vehicle time and deceleration shown in FIG. .

In step S111, it is checked whether or not the brake SW8 is off (the brake is not operated). If the brake operation is performed by the driver, the driver decreases the inter-vehicle distance with the preceding vehicle. Then, it is determined that the brake operation has been performed, and the operation is performed as the inter-vehicle time when the brake operation is performed in step S118 because the operation in the resume state is performed, and the process returns to step S107.

On the other hand, when the brake SW8 is not operated by the driver, a target acceleration / deceleration calculation is performed in step S112. The target acceleration / deceleration calculation X is obtained by the following equation. That is, if the current inter-vehicle distance: Lc, target inter-vehicle distance: Lt, relative speed: Vr, and K1 and K2: constants, X = K1 · (Lc−Lt) + K2 · Vr by PD control. In this case, the target acceleration / deceleration X takes on the characteristics shown in FIG. 5 corresponding to the calculation result, and -X1, X2 (X1, X2
> 0), a dead zone is provided. When X> 0, acceleration (throttle control) is performed, and when X <0, deceleration (brake control) is performed. In step S113, the dead zone area-X
If 1 <X <X2, throttle control is performed in step S119. In this case, the target throttle opening Θt is calculated by using a throttle opening map Θmap corresponding to the vehicle speed V Θt = Θm
ap (spd) (spd: vehicle speed V). If X is equal to or greater than zero (X is equal to or greater than X2), throttle control is performed in step S119 with the target throttle opening Δt set to Δt = Δmap (spd) + K3 · X (K3: constant).

On the other hand, when X is equal to or less than zero (X is equal to or less than -X1), deceleration is performed. In this case, a target deceleration calculation is performed in step S115, and the target deceleration Gt is calculated as Gt = K4
Calculate with X (K4: constant). After the target deceleration Gt is determined, the vehicle is decelerated so as to be the target deceleration from the current vehicle speed. However, if the deceleration is abruptly performed, the driver may feel uneasy. The deceleration is set and control is performed so that the target deceleration is gradually achieved. That is, in step S116, the auxiliary target deceleration Gtsub is calculated by the auxiliary target deceleration calculation, for example, using a characteristic map (specifically, t1: 0.1 sec, t2: 1...) Based on the inter-vehicle time and the target deceleration Gt shown in FIG. 5 sec, Gt: 0.
3G / sec). This characteristic map is provided so as to be variable depending on the inter-vehicle time with respect to the target deceleration, and has a gradient with respect to the inter-vehicle time until the target deceleration is reached. Also, the gradient is variable than the inter-vehicle time. The gradient is set so that the longer the inter-vehicle time, the gentler the gradient, and the shorter the inter-vehicle time, the steeper the gradient. Thereafter, in step S117, automatic brake control is performed, and the process returns to step S102, and returns from step S102 to step S102.
119 is repeated.

Thus, until the target deceleration is reached,
By providing the auxiliary target deceleration Gtsub that can be varied according to the inter-vehicle time, the vehicle is gradually decelerated until the target deceleration is reached, so that no sharp deceleration occurs, so that the driver's anxiety during deceleration is eliminated. be able to.

[0024]

According to the present invention, a vehicle speed sensor for detecting the speed of a vehicle, an inter-vehicle distance sensor for detecting an inter-vehicle distance to a preceding vehicle, and a current inter-vehicle distance from a preceding vehicle based on information from the vehicle speed sensor and the inter-vehicle distance sensor. A controller that calculates the distance, the target inter-vehicle distance, and the relative speed, calculates the target acceleration / deceleration, and adjusts the vehicle speed adjustment device, and obtains the target deceleration with respect to the calculated target acceleration / deceleration to decelerate. When performing deceleration, by setting the auxiliary target deceleration, the target deceleration is calculated from the calculated target acceleration / deceleration, and when decelerating, the auxiliary target deceleration is set, so until the vehicle reaches the target deceleration Auxiliary target deceleration makes it possible to gradually decelerate, so that rapid deceleration to the target deceleration does not occur and the driver does not feel uneasy during deceleration .

In this case, if the auxiliary target deceleration has a gradient with respect to the time required to reach the target deceleration,
It is possible to make a change by an appropriate gradient according to the time until the target deceleration is reached.

The gradient of the auxiliary target deceleration is determined by the inter-vehicle time (the time until the vehicle reaches the position of the preceding vehicle at the current traveling speed). If the inter-vehicle time is long, the gradient is gentle; If the setting is made abruptly, the setting according to the inter-vehicle time becomes possible, and the driver does not feel uneasy.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration of a travel control device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a process of a controller of the travel control device according to the embodiment of the present invention.

FIG. 3 is a diagram illustrating a relationship between a vehicle speed and a target inter-vehicle distance with the inter-vehicle time as a parameter of the travel control device according to the embodiment of the present invention.

FIG. 4 is a diagram illustrating a relationship between an inter-vehicle time and a target deceleration gradient of the travel control device according to the embodiment of the present invention.

FIG. 5 is a diagram illustrating a relationship between acceleration and deceleration by a target acceleration / deceleration of the travel control device according to the embodiment of the present invention.

FIG. 6 is a diagram showing a relationship between an inter-vehicle time and an auxiliary target deceleration based on a target deceleration in the embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 travel control device 5 system SW 6 following distance sensor 7 vehicle speed sensor 9 cruise switch 10 controller 13 operating lever 21 throttle device (vehicle speed adjusting device) 22 brake device (vehicle speed adjusting device) Gt target deceleration Gtsub auxiliary target deceleration

Claims (3)

[Claims] A vehicle speed sensor for detecting a speed of the vehicle, an inter-vehicle distance sensor for detecting an inter-vehicle distance to a preceding vehicle, a current inter-vehicle distance to a preceding vehicle based on information from the vehicle speed sensor and the inter-vehicle distance sensor, When a deceleration is performed by obtaining a target deceleration from the calculated target acceleration / deceleration in a travel control device including a controller that obtains a target inter-vehicle distance and a relative speed, calculates a target acceleration / deceleration, and adjusts a vehicle speed adjustment device. A travel control device for setting an auxiliary target deceleration. 2. The travel control device according to claim 1, wherein the auxiliary target deceleration has a gradient with respect to a time until the target deceleration is reached. 3. The travel control device according to claim 2, wherein a gradient of the auxiliary target deceleration is determined by an inter-vehicle time, and the gradient is set to be gentle if the inter-vehicle time is long and to be sharp if the inter-vehicle time is short.