JP2003039977A - Preceding vehicle follow-up control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict and prevent giving a sense of discomfort to a driver that one's vehicle is left behind by a preceding vehicle at start of the preceding vehicle. SOLUTION: At start of the preceding vehicle, a target inter-vehicle distance LT is set using a secondary delay format filter based on an inter-vehicle distance L between the own vehicle and the preceding vehicle and a predetermined inter-vehicle distance command value L* and a braking/driving force is controlled so that the actual inter-vehicle distance L accords with the target inter- vehicle distance LT, and at stop of the own vehicle, if the actual inter-vehicle distance L is smaller than the inter-vehicle distance command value L*, the target inter-vehicle distance LT is set using the secondary delay format filter including a time delay element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention sets a target inter-vehicle distance that changes smoothly based on an actual inter-vehicle distance between a host vehicle and a preceding vehicle and a predetermined inter-vehicle distance command value. The present invention relates to a preceding vehicle slave control device that controls a braking / driving force so that an actual inter-vehicle distance coincides with a distance so that the host vehicle follows a preceding vehicle.

[0002]

2. Description of the Related Art Conventionally, as a preceding vehicle follow-up control device of this type, one disclosed in, for example, Japanese Patent Laid-Open No. 2000-135934 is known. In this conventional example, a target inter-vehicle distance is calculated using a second-order lag low-pass filter based on the inter-vehicle distance between a host vehicle and a preceding vehicle and a predetermined inter-vehicle distance command value, and the target inter-vehicle distance is calculated. Discloses a method of controlling the braking / driving force so that the inter-vehicle distances match.

[0003]

However, in the above-mentioned conventional example, since the target inter-vehicle distance is calculated by using the low-pass filter of the second-order lag type, for example, the preceding vehicle is followed by the own vehicle due to traffic congestion or the like. If the vehicle-to-vehicle distance is smaller than the vehicle-to-vehicle distance command value when the vehicle stops, the vehicle will not start until the vehicle-to-vehicle distance exceeds the target vehicle-to-vehicle distance, even if the vehicle is trying to start following the preceding vehicle. Also, since the target inter-vehicle distance increases with time, the host vehicle may not start even though the preceding vehicle is starting,
There is a problem that the occupant feels uncomfortable that the host vehicle is left behind in the preceding vehicle even though the follow-up control is being performed.

Therefore, the present invention has been made by paying attention to the unsolved problems of the above-mentioned conventional techniques, and suppresses the discomfort that the own vehicle is left behind when the preceding vehicle starts. An object of the present invention is to provide a preceding vehicle following control device that can be prevented.

[0005]

In order to solve the above-mentioned problems, a preceding vehicle following device according to the invention of claim 1 is an inter-vehicle distance detecting means for detecting an inter-vehicle distance between a host vehicle and a preceding vehicle. , An inter-vehicle distance command value setting means for setting a predetermined inter-vehicle distance command value, and a predetermined function based on the inter-vehicle distance detected by the inter-vehicle distance detecting means and the inter-vehicle distance command value set by the inter-vehicle distance command value setting means. Target inter-vehicle distance setting means for setting a target inter-vehicle distance by using the inter-vehicle distance detected by the inter-vehicle distance detecting means and the inter-vehicle distance detected by the inter-vehicle distance detecting means are controlled. Braking / driving force control means, wherein the target inter-vehicle distance setting means, when the host vehicle is stopped, the inter-vehicle distance detected by the inter-vehicle distance detecting means is the inter-vehicle distance set by the inter-vehicle distance command value setting means. Command When smaller, and sets using slow function response characteristic target inter-vehicle distance.

According to a second aspect of the present invention, in the preceding vehicle following device according to the first aspect, the function having a slow response characteristic includes a function representing a dead time. Further, in the invention according to claim 3, in the preceding vehicle follow-up device according to claim 2, the dead time is set by the inter-vehicle distance detected by the inter-vehicle distance detecting means when the vehicle is stopped and the inter-vehicle distance command value setting means. It is characterized in that it is set to a large value according to the magnitude of the difference from the inter-vehicle distance command value.

According to a fourth aspect of the present invention, in the preceding vehicle follow-up device according to the first aspect, the function having a slow response characteristic is a function in which the time change rate of the target inter-vehicle distance in the initial stage of starting is negative. It is characterized by According to a fifth aspect of the present invention, in the preceding vehicle follow-up device according to the fourth aspect, the time change rate of the target inter-vehicle distance in the initial stage of starting is set to be large according to the magnitude of the inter-vehicle distance when the vehicle is stopped. Is characterized by.

Further, the invention according to claim 6 is the same as claim 1.
In the preceding vehicle following device according to any one of claims 5 to 5, the target inter-vehicle distance setting means regulates the target inter-vehicle distance calculated by a function having a slow response characteristic at a predetermined minimum inter-vehicle distance. Further, the invention according to claim 7 is the preceding vehicle follow-up device according to any one of claims 1 to 6, wherein the target inter-vehicle distance setting means sets the target inter-vehicle distance by the inter-vehicle distance command value setting means. The target inter-vehicle distance is set using a function having a slow response characteristic until the specified inter-vehicle distance command value is satisfied.

The invention according to claim 8 is the preceding vehicle following device according to any one of claims 1 to 7, further comprising a relative vehicle speed detecting means for detecting a relative vehicle speed between the own vehicle and the preceding vehicle. The target inter-vehicle distance setting means, until the relative vehicle speed detected by the relative vehicle speed detecting means becomes negative,
The feature is that the target inter-vehicle distance is set using a function having a slow response characteristic.

[0010]

Therefore, in the preceding vehicle follow-up control device according to the invention of claim 1, a predetermined function is established based on the following distance between the host vehicle and the preceding vehicle and a given distance command value. The target inter-vehicle distance is set using, and the braking / driving force is controlled so that the inter-vehicle distance matches the target inter-vehicle distance.For example, when the inter-vehicle distance when the vehicle is stopped is smaller than the inter-vehicle distance command value, Even if the inter-vehicle distance is smaller than the inter-vehicle distance command value, the target inter-vehicle distance is the same or almost the same as when the vehicle is stopped, even if the inter-vehicle distance is smaller than the inter-vehicle distance command value. Since the braking / driving force is controlled so that the actual vehicle-to-vehicle distance matches the target vehicle-to-vehicle distance, the host vehicle starts in the same way as or slightly later than the preceding vehicle. vehicle That would give a sense of discomfort as Ika placed occupant can be prevented suppressed.

Further, in the preceding vehicle following control device according to the invention of claim 2, the function having a slow response characteristic is
Since the function to represent the dead time is included, even if the inter-vehicle distance when the vehicle is stopped is smaller than the inter-vehicle distance command value, when the host vehicle is started following the preceding vehicle, the target inter-vehicle distance is Since the values are the same and the braking / driving force is controlled so that the inter-vehicle distance matches the target inter-vehicle distance,
The own vehicle starts in the same manner as the preceding vehicle, and when the preceding vehicle starts, it is possible to effectively suppress and prevent the occupant from feeling uncomfortable as if the own vehicle were left behind.

Further, in the preceding vehicle following control device of the invention according to claim 3, the dead time is set to a large value in accordance with the magnitude of the difference between the inter-vehicle distance when the vehicle is stopped and the inter-vehicle distance command value. Therefore, if the difference between the inter-vehicle distance when the vehicle is stopped and the inter-vehicle distance command value is large, the dead time is set to a large value, and even after the vehicle has started, the host vehicle follows the preceding vehicle to maintain the inter-vehicle distance when the vehicle is stopped. After running, even after the preceding vehicle has started,
It is possible to prevent the occupant from feeling uncomfortable when the host vehicle is left behind.

Further, in the preceding vehicle following control device according to the invention of claim 4, the function having the slow response characteristic is
Since the time change rate of the target inter-vehicle distance in the initial stage of starting is a negative function, even when the inter-vehicle distance when the vehicle is stopped is smaller than the inter-vehicle distance command value, when the own vehicle is started following the preceding vehicle, The target inter-vehicle distance is set smaller than the inter-vehicle distance when the vehicle is stopped, the braking / driving force is controlled so that the inter-vehicle distance matches the target inter-vehicle distance, and the host vehicle starts with a greater acceleration than the preceding vehicle. It is possible to effectively suppress and prevent an occupant from having an uncomfortable feeling that the own vehicle is left when the preceding vehicle starts.

Further, in the preceding vehicle following control device according to the invention of claim 5, the time change rate in the initial stage of the starting is set to be large according to the size of the inter-vehicle distance when the vehicle is stopped. Therefore, when the inter-vehicle distance is large and the risk of the host vehicle approaching the preceding vehicle is small, the host vehicle accelerates more greatly and starts, and when the preceding vehicle starts, the host vehicle is left behind in the preceding vehicle. It is possible to effectively suppress and prevent the passenger from feeling uncomfortable.

Further, in the preceding vehicle follow-up control device according to the invention of claim 6, since the target inter-vehicle distance calculated by the function having the slow response characteristic is restricted to a predetermined minimum inter-vehicle distance, the preceding vehicle is started. At this time, even if the host vehicle starts with a larger acceleration than the preceding vehicle, it does not approach the preceding vehicle more than the minimum inter-vehicle distance, and it is possible to effectively prevent the driver from feeling uncomfortable.

In the preceding vehicle following control device according to the invention of claim 7, the target inter-vehicle distance setting means sets the target inter-vehicle distance to the response characteristic until the target inter-vehicle distance matches the inter-vehicle distance command value. Since it is set by using a slow function of, for example, after the target inter-vehicle distance matches the inter-vehicle distance command value, if a function with a fast response characteristic is used as the function used for setting the target inter-vehicle distance, It is possible to ensure the followability of the host vehicle to the acceleration and deceleration of the vehicle.

Further, in the preceding vehicle follow-up control device according to the invention of claim 8, the target inter-vehicle distance is calculated by using a function having a slow response characteristic until the relative vehicle speed between the own vehicle and the preceding vehicle becomes negative. Since the setting is made, for example, even when the preceding vehicle decelerates, the host vehicle does not approach the preceding vehicle, and it is possible to prevent the driver from feeling uncomfortable.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a preceding vehicle following control device according to the present invention will be described below with reference to the drawings. Figure 1
1 is a schematic configuration diagram showing an embodiment of the present invention, in which 1FL and 1FR are front wheels as driven wheels, 1RL, and 1FR.
RR is a rear wheel as a driving wheel, and rear wheels 1RL, 1R
The R is rotationally driven by the driving force of the engine 2 being transmitted via the automatic transmission 3, the propeller shaft 4, the final reduction gear 5, and the axle 6.

Front wheels 1FL, 1FR and rear wheels 1RL, 1R
R is provided with a disc brake 7 as a brake actuator that generates a braking force, and
The braking oil pressure of these disc brakes 7 is controlled by the braking control device 8.
Controlled by. Here, the braking control device 8 is configured to generate the braking oil pressure in response to the depression of the brake pedal 8a, and to generate the braking oil pressure in accordance with the braking pressure command value from the tracking control controller 20 described later. There is.

Further, the engine 2 is provided with an engine output control device 9 for controlling its output. The engine output control device 9 controls a throttle actuator 10 provided in the engine 2 for adjusting a throttle opening according to a depression amount of an accelerator pedal 9a and a throttle opening command value from a tracking control controller 20 described later. To be configured.

Further, the automatic transmission 3 is provided with a transmission control device 11 for controlling the shift position and the working fluid pressure suitable for the shift position. This transmission control device 11
Is configured to control the shift position and the working fluid pressure of the automatic transmission 3 in accordance with the depression amount of the accelerator pedal 9a and the shift command value from the follow-up control controller 20 described later.

On the other hand, an inter-vehicle distance sensor 12 having a radar type structure for sweeping a laser beam and receiving a reflected light from a preceding vehicle is provided under the vehicle body on the front side of the vehicle. The inter-vehicle distance sensor 12 measures the time from when the laser beam is swept until the reflected light of the preceding vehicle is received to detect the inter-vehicle distance L between the own vehicle and the preceding vehicle, and
The detected value of the inter-vehicle distance L is differentiated to calculate the relative speed ΔV between the own vehicle and the preceding vehicle, and these are output to the follow-up control controller 20. Note that the method of calculating the relative speed ΔV from the inter-vehicle distance L may be changed to a method of differentiating the detection value of the inter-vehicle distance L and, for example, a band bass filter may be used. The inter-vehicle distance sensor 12 may be any one that can detect the inter-vehicle distance L, and may be one that detects the inter-vehicle distance L or the like by using radio waves or ultrasonic waves instead of laser light.

Further, the vehicle is provided with, for example, a vehicle speed sensor 13 which is attached to the propeller shaft 4 and detects the own vehicle speed V based on the rotation speed of the propeller shaft 4. The inter-vehicle distance L and the relative speed ΔV output from the inter-vehicle distance sensor 12 and the own vehicle speed V output from the vehicle speed sensor 13 are input to the tracking control controller 20. The follow-up control controller 20 is composed of a discretized digital system such as a microcomputer (not shown), executes a follow-up control process described later, and when the preceding vehicle is captured, the inter-vehicle distance L is changed to the target inter-vehicle distance L ^*. The braking pressure command value, the target throttle opening degree, and the gear shift command value that are controlled to be output to the braking control device 8, the engine output control device 9, and the transmission control device 11.

The follow-up control processing in the present embodiment constitutes a control block shown in FIG. 2 by a software form of a microcomputer. The control block includes an inter-vehicle distance command value calculation unit 31, a follow-up control mode selection unit. 32, a target inter-vehicle distance calculation constant determination unit 33, a target inter-vehicle distance calculation unit 34, and a vehicle speed command value calculation unit 35.
The inter-vehicle distance command value calculation unit 31 calculates the inter-vehicle distance command value L ^* based on the relative speed ΔV detected by the inter-vehicle distance sensor 12 and the own vehicle speed V detected by the vehicle speed sensor 13 to the vehicle speed V _{t of the} preceding vehicle. It is calculated according to the following equation (1) as a function of (= V + ΔV), and the calculation result is calculated by the follow-up control mode selection unit 3
2. Perform processing to output to the target inter-vehicle distance calculation constant determination unit 33 and the target inter-vehicle distance calculation unit 34.

L ^* = a · V _t tens L _of = a · (V + ΔV) tens L _of (1) where a is a coefficient and L _of is an offset value. The method of calculating the inter-vehicle distance command value L ^* is not limited to the above equation (1), and may be calculated according to the following equation (2) as a function of the own vehicle speed V. Instead of calculating, the occupant may set the value.

L ^* = a'.V + L _of ... (2) where a'is a coefficient. Further, the follow-up control mode selection unit 32 is calculated by the inter-vehicle distance L and the relative speed ΔV detected by the inter-vehicle distance sensor 12, the vehicle speed V of the own vehicle detected by the vehicle speed sensor 13, and the inter-vehicle distance command value calculation unit 31. Based on the inter-vehicle distance command value L ^* and the target inter-vehicle distance L _T calculated by the target inter-vehicle distance calculation unit 34, one of three predetermined follow-up control modes is selected according to the follow-up situation. Then, the process of outputting the selection result to the target inter-vehicle distance calculation unit 34 is performed.

On the other hand, the target vehicle distance calculation constant determining unit 33
In the inter-vehicle distance control system in which the inter-vehicle distance command value L ^* calculated by the inter-vehicle distance command value calculation unit 31 is input and the inter-vehicle distance L detected by the inter-vehicle distance sensor 12 is output, the actual inter-vehicle distance L is In order to make the response characteristic of the inter-vehicle distance control system preferable until the inter-vehicle distance command value L ^* is reached,
The damping coefficient ζ _T and the natural frequency ω _T of the inter-vehicle distance control system are determined according to the inter-vehicle distance deviation ΔL (= L−L ^* ) and the relative speed ΔV.

Specifically, the damping coefficient ζ _T and the natural frequency ω of the inter-vehicle distance control system corresponding to the inter-vehicle distance deviation ΔL and the relative speed ΔV are obtained so that preferable response characteristics can be obtained in various follow-up situations. _T and _T are set in advance as a map, and during follow-up control, the damping coefficient ζ _T and the natural frequency ω _T corresponding to the inter-vehicle distance deviation ΔL and the relative speed ΔV are read from the map. Table 1 shows a map example of the damping coefficient ζ _T , and Table 2 shows a map example of the natural frequency ω _T.

[0029]

[Table 1]

[0030]

[Table 2]

The target vehicle distance calculation unit 34 is a filter associated with the tracking control mode selected by the tracking control mode selection unit 32, and is determined by the target vehicle distance calculation constant determination unit 33. The damping coefficient ζ _T and the natural frequency ω _T are used to set the coefficients, and are set when the inter-vehicle distance command value L ^* calculated by the inter-vehicle distance command value calculation unit 31 and the preceding vehicle are supplemented. Based on the vehicle-to-vehicle distance L _o , the target vehicle-to-vehicle distance L _T and the target relative speed ΔV _T are calculated, and the calculation results are output to the vehicle speed command value calculation unit 35. The tracking control mode 0 corresponds to the low-pass fill of the second-order lag type, and the tracking control mode 1
Corresponds to a low-pass filter of the second-order lag type including dead time, and the tracking control mode 2 corresponds to an inverse response filter expressed by a transfer function of a non-minimum phase system.

Further, the vehicle speed command value calculation unit 35 determines the vehicle speed command value V ^* based on the target vehicle distance L _T calculated by the target vehicle distance calculation unit 34 and the target relative speed ΔV _T (3) below.
The calculation is performed according to the formula, and the calculation result is output to the vehicle speed control unit 36. V ^* = V (t) + ΔV (t) − [f _V {ΔV _T (t) 1 ΔV (t)} + f _L {L _T (t) 1 L (t)}] ………… ( 3) However, f _V and f _L are constants.

Then, the vehicle speed control unit 36 displays the vehicle speed command value.
Vehicle speed command value V calculated by the calculator 35 ^*Match the vehicle speed V with
Throttle opening command value, braking hydraulic pressure command value and
And shift command values are calculated, and the calculated values are used as an engine output control device.
9, output to the braking control device 8 and the transmission control device 11
It Vehicle speed command value V^*To match the vehicle speed V to
As a method, a feedback control method or JP-A-200-200
Robust model match described in 0-135934
Various control methods, such as
It

Next, the processing performed by the follow-up control mode selection unit 32 of FIG. 2 will be described in detail with reference to the flowchart of FIG. First, when this process is executed, the process proceeds to step S1, and in step S1, it is determined whether or not the follow-up control mode 0 is selected, and when the follow-up control mode 0 is selected. (Yes) Moves to step S2, and if not (No) moves to step S8. In the initial state, follow-up control mode 0 is selected as the type of follow-up control mode.

In step S2, it is determined whether or not the vehicle speed V of the host vehicle detected by the vehicle speed sensor 13 is "0". When the vehicle speed V is "0" (Yes), the process proceeds to step S3, and otherwise. (No) This process ends. In step S3, it is determined whether the relative speed ΔV detected by the inter-vehicle distance sensor 12 is “0”,
If it is "0" (Yes), the process proceeds to step S4, and if not (No), this process ends.

In step S4, the inter-vehicle distance sensor 1
Inter-vehicle distance L when the vehicle is stopped detected in 2 _oIs the inter-vehicle distance command value
Inter-vehicle distance command value L calculated by the calculation unit 31_o ^*Less than
(L_o<L_o ^*), And when it is smaller (Ye
s) Go to step S5, otherwise (N
o) This process ends. In step S5,
Inter-vehicle distance L when stopped by the distance sensor 12 _oWhere
Fixed minimum distance L_minLess than (L_o<L_min) Or not
If it is smaller (Yes), go to step S6.
If not (No), move to step S7
To go.

In step S6, the follow-up control mode 1 is selected as the kind of the follow-up control mode, and then this process is terminated. Further, in step S7, the follow-up control mode 2 is selected as the type of the follow-up control mode, and then this processing is ended. On the other hand, in step S8, the vehicle speed V _t of the preceding vehicle is calculated based on the relative speed ΔV detected by the inter-vehicle distance sensor 12 and the own vehicle speed V detected by the vehicle speed sensor 13, and the preceding vehicle decelerates. If it is decelerating (Yes), the process proceeds to step S10, and if not (No), the process proceeds to step S9.

In step S9, it is determined whether the inter-vehicle distance command value L ^* calculated by the inter-vehicle distance command value calculation unit 31 and the target inter-vehicle distance L _T calculated by the target inter-vehicle distance calculation unit 34 match. And if they match (Yes)
The process proceeds to step S10, and if not (N
o) This process ends. Further, in step S10, the follow-up control mode 0 is selected as the type of the follow-up control mode, and this processing is ended.

Next, the processing performed by the target inter-vehicle distance calculating section 34 of FIG. 2 will be described in detail with reference to the block diagram of FIG. This processing constitutes the control block shown in FIG. 4, which is based on the inter-vehicle distance command value L ^* , the damping coefficient ζ _T, and the natural frequency ω _T, and the low-pass filter including the dead time. Target inter-vehicle distance calculation unit A 341 for calculating target inter-vehicle distance L _TA and target inter-vehicle distance calculation unit B for calculating target inter-vehicle distance L _TB by inverse response filter of non-minimum phase system
342, the target inter-vehicle distance calculation unit C343 that calculates the target inter-vehicle distance L _TC with the low-pass filter, and the target inter-vehicle distance L _TA L _TB L _TC calculated by the target inter-vehicle distance calculation units 341, 342, and 343. Based on the selection result of the tracking control mode selection unit 32, the tracking control mode switching unit 3 that outputs the target inter-vehicle distance L _T to the vehicle speed control unit 36 and the like.
44 and.

The target inter-vehicle distance calculation unit A341 calculates the damping coefficient ζ _T determined by the target inter-vehicle distance calculation constant determination unit 33 based on the inter-vehicle distance command value L ^* calculated by the inter-vehicle distance command value calculation unit 31. A target inter-vehicle distance L _TA and a target relative speed ΔV _TA are calculated according to the following equation (4) including a time delay element in a second-order lag type low-pass filter having a natural frequency ω _T , and the calculation results are used in a tracking control mode. Switching unit 344
Output to. In the formula (4) below, the vehicle speed sensor 13
Inter-vehicle distance _Lo and relative speed ΔV detected at
Let _{o be} the initial values of the target inter-vehicle distance L _TA and the target relative speed ΔV _TA .

[0041]

[Equation 1]

When the above equation (4) is Laplace transformed, it is expressed as the following equation (5).

[0043]

[Equation 2]

The above equation (5) is a transfer function when the inter-vehicle distance command value L ^* is input and the target inter-vehicle distance L _TA is output, and since it has a dead time element, as shown in FIG. actual vehicle-to-vehicle distance L large vehicle-to-vehicle distance command value than the _o L ^*
Even when is input, the inter-vehicle distance L _o when the vehicle is stopped is output as the target inter-vehicle distance L _TA over the dead time T. The dead time T of the target inter-vehicle distance calculation unit A341 uses a dead time map as shown in FIG. 6, and as shown in FIG. 7, a deviation rate β representing the difference between the inter-vehicle distance command value L ^* and the inter-vehicle distance L. Set it larger according to the size of. Deviation rate beta, is calculated by the following equation (6) based on the inter-vehicle distance command value L _o ^* and inter-vehicle distance L _o when the vehicle has stopped.

Β = (L _o ^* −L _o ) / L _o ^* × 100 (6) However, L _o ^* > L _o . The method of obtaining the dead time T is not limited to the method of using the deviation rate β, and, for example, using the inter-vehicle distance L _o when the vehicle is stopped as a parameter, it is possible to match the feeling of the occupant in advance through experiments or the like. A map of the time T may be created and the map may be used to directly obtain from the inter-vehicle distance L _o .

Further, the target inter-vehicle distance calculating section B 342 has the inter-vehicle distance command value L calculated by the inter-vehicle distance command value calculating section 31.
Based on ^* , the non-minimum phase system low-pass filter having the damping coefficient ζ _T and the natural frequency ω _T determined by the target inter-vehicle distance calculation constant determining unit 33, and the output of the low-pass filter are set to the predetermined minimum inter-vehicle distance. And a limiter that limits by L _min . The low-pass filter is (6) below.
The target inter-vehicle distance L _TB and the target relative speed ΔV _TB are calculated according to the formulas, and the limiter limits the calculation result and outputs it to the tracking control mode switching unit 344. In addition, the following (6)
In the formula, the inter-vehicle distance L _o and the relative velocity △ V _o when the vehicle is stopped that is detected by the vehicle speed sensor 13, the initial value of the target inter-vehicle distance L _TB and target relative speed △ V _TB.

[0047]

[Equation 3]

When the above equation (6) is Laplace transformed, it is expressed as the following equation (7).

[0049]

[Equation 4]

The above equation (7) is a transfer function when the inter-vehicle distance command value L ^* is input and the target inter-vehicle distance L _TB is output, and is a non-minimum phase system having a positive zero "1 / α". Therefore, as shown in FIG. 8, when the inter-vehicle distance command value L ^* that is larger than the actual inter-vehicle distance L _o is input, the target inter-vehicle distance L _TB is once calculated small and then gradually increased. Make a shaking response. At that time, the minimum distance L
_{Since the} target inter-vehicle distance L _TB is limited by _min , even if the target inter-vehicle distance L _TB is calculated to be small by the inverse response filter, the target inter-vehicle distance L _TB output to the tracking control mode switching unit 344 is the minimum inter-vehicle distance L _TB. It cannot be shorter than _min .

[0051] Incidentally, inverse response Phil evening coefficients of the target inter-vehicle distance calculating unit B 342 alpha, using a map as shown in FIG. 9, as shown in FIG. 10, the inter-vehicle distance L _o and minimum following distance at stop It is set to a large value according to the magnitude of the vehicle-to-vehicle distance deviation ΔL _o #min which is the difference from L _min . Further, the method of obtaining the coefficient α is not limited to the method of using the inter-vehicle distance deviation ΔL _{o #min} . For example, the feeling of the occupant can be preliminarily determined by experiments or the like using the inter-vehicle distance L _o when the vehicle is stopped as a parameter. It is also possible to create a map of the coefficient α that agrees with and to obtain it directly from the inter-vehicle distance L _o .

On the other hand, the target inter-vehicle distance calculation unit C343 has the inter-vehicle distance command value L calculated by the inter-vehicle distance command value calculation unit 31.
Based on ^* , the target inter-vehicle distance L is calculated according to the following equation (8), which represents a second-order lag type low-pass filter having the damping coefficient ζ _T and the natural frequency ω _T determined by the target inter-vehicle distance calculation constant determining unit 33. _Tc and the target relative speed ΔV _Tc are calculated, and the calculation result is output to the tracking control mode switching unit 344. Incidentally, when the follow-up control mode 0, the headway distance L _o and the relative velocity △ V _o immediately after capturing the preceding vehicle as the initial value of the target inter-vehicle distance L _Tc and the target relative speed △ V _Tc, the type of follow-up control mode However, when the tracking control mode 1 or the tracking control mode 2 is switched to the tracking control mode 0, the inter-vehicle distance L and the relative speed ΔV immediately after the switching are set as initial values.

[0053]

[Equation 5]

When the above equation (8) is Laplace transformed, it is expressed as the following equation (9).

[0055]

[Equation 6]

The above equation (9) is a transfer function when the inter-vehicle distance command value L ^* is input and the target inter-vehicle distance L _TA is output, and since it has a second-order lag element, as shown in FIG. , than the actual vehicle-to-vehicle distance L _o large vehicle-to-vehicle distance command value L ^*
When is input, the target inter-vehicle distance L _TB is gradually increased from the initial value. Then, the follow-up control mode switching unit 34 selects the target inter-vehicle distance calculation units 341, 342, 343 corresponding to the selected follow-up control mode based on the selection result of the follow-up control mode selection unit 32, and the target thereof. Inter-vehicle distance calculator 341, 342, 343
Output the target inter-vehicle distance L _T and the relative speed ΔV _T to the vehicle speed command value calculation unit 35 and the follow-up control mode selection unit 32. The type of follow-up control mode, the follow-up when the control mode 0, outputs the target inter-vehicle distance calculated by the target inter-vehicle distance calculating section C343 L _Tc and the target relative speed △ V _Tc,
Further, when the follow-up control mode 1, outputs the target inter-vehicle distance calculated by the target inter-vehicle distance calculating section A 341 L _TA and target relative speed △ V _TA, Further, when the follow-up control mode 2, the target inter-vehicle distance calculating section B342 in outputting the calculated target inter-vehicle distance L _TB and target relative speed △ V _TB.

Next, the operation of this embodiment will be described in detail based on a specific situation. First, when a traffic jam occurs while traveling on an expressway and the host vehicle stops following the preceding vehicle, as shown in FIG. 12, the driver drives the host vehicle to follow the preceding vehicle and start. Suppose that the user has performed an operation to start tracking control. Then, the follow-up control controller 2
0, the follow-up control process is executed, and as shown in the block diagram of FIG. 2, first, the process of the inter-vehicle distance command value calculation unit 31 is executed, and the relative speed Δ detected by the inter-vehicle distance sensor 12
The inter-vehicle distance command value L ^* is calculated based on V and the own vehicle speed V detected by the vehicle speed sensor 13, and the calculation result is the follow-up control mode selection unit 32, the target inter-vehicle distance calculation constant determination unit 33, and the target inter-vehicle distance. It is output to the distance calculation unit 34.

Next, the target vehicle distance calculation constant determining unit 3
3 is executed, and the inter-vehicle distance deviation ΔL and the inter-vehicle distance deviation L and the relative speed ΔV detected by the inter-vehicle distance sensor 12 and the inter-vehicle distance command value L ^* calculated by the inter-vehicle distance command value calculation unit 31 are executed. The damping coefficient ζ _T and the natural frequency ω _{T of} the inter-vehicle distance control system are determined according to the relative speed ΔV. At the same time, the processing of the tracking control mode selection unit 32 is also executed,
As shown in the flowchart of FIG. 3, first, since the type of the tracking control mode is set to the tracking control mode 0,
Since the determination in step S1 is “Yes” and the own vehicle is stopped following the preceding vehicle, steps S2 and S
The determination of 3 is also “Yes”, the degree of traffic congestion is high, and the inter-vehicle distance L _o when the vehicle is stopped is the minimum inter-vehicle distance L _min.
If it is smaller, steps S4 and S5
Also becomes "Yes", and the follow-up control mode 1 is selected as the type of the follow-up control mode in step S6.

Then, the processing of the target inter-vehicle distance calculation unit 34 is executed, and as shown in the block diagram of FIG. 4, based on the inter-vehicle distance command value L ^* , the damping coefficient ζ _T and the natural frequency ω _T , The target inter-vehicle distance calculation unit A 341 having the low-pass fill setting including the dead time calculates the target inter-vehicle distance L _TA , and the target inter-vehicle distance calculation unit B 34 having the reverse response fill setting.
The target inter-vehicle distance L _TB is calculated in 2, and the target inter-vehicle distance L _TC is further calculated in the target inter-vehicle distance calculation unit C343 having a low-pass filter. Next, from among the target inter-vehicle distances L _TA L _TB L _TC calculated by the target inter-vehicle distance calculation units 341, 342, 343, the target inter-vehicle distance calculation unit A 341 associated with the follow-up control mode 1 calculates. As shown in FIG. 5, the target inter-vehicle distance L _TA is output from the tracking control mode switching unit 344 to the vehicle speed control unit 36 as the target inter-vehicle distance L _T.

Further, the vehicle speed command value calculation unit 35 to which the target vehicle distance L _T has been input calculates the vehicle speed command value V ^* based on the target vehicle distance L _T , and the vehicle speed control unit 36 calculates the vehicle speed command value. A throttle opening command value, a braking hydraulic pressure command value, and a gear shift command value for matching the vehicle speed V with V ^* are calculated and output to the braking control device 8, the engine output control device 9, and the transmission control device 11. It Then, the engine output control device 9 or the like, to which the throttle opening command value or the like has been input, controls the braking / driving force so that the actual inter-vehicle distance L matches the target inter-vehicle distance L ^* , and when the preceding vehicle starts. Since the own vehicle starts in the same way as the preceding vehicle so that the inter-vehicle distance L between the own vehicle and the preceding vehicle becomes the same value as when the vehicle stopped, the occupant feels uncomfortable as if the own vehicle were left behind. It can be suppressed and prevented.

Further, the target inter-vehicle distance calculation unit A341
Vehicle distance L_TAAs shown in FIG. 6, when calculating
Is the time T, and the distance L_oAnd inter-vehicle distance command value L_o
^*It is set to a large value according to the deviation rate β that represents the magnitude of the difference between
Therefore, for example, your vehicle stops following the preceding vehicle due to traffic congestion.
When driving, the actual vehicle-to-vehicle distance L and the vehicle-to-vehicle distance command value L _o ^*
If the difference is large, the dead time T becomes large as shown in FIG.
Since it will be set faster, the distance between your vehicle and the
Distance L_oFollows to maintain the
Occasionally, the occupant feels uncomfortable as if his / her vehicle is left behind.
It is possible to prevent or prevent the occurrence.

On the other hand, if the degree of congestion is low and the inter-vehicle distance L _o when the vehicle is stopped is smaller than the minimum inter-vehicle distance L _min , when the processing of the follow-up control mode selection unit 32 is executed, the result shown in FIG. As shown, through steps S1 to S4,
The determination in step S5 is “No”, and step S7
Then, the follow-up control mode 2 is selected as the kind of the follow-up control mode. Then, in the target inter-vehicle distance calculation unit 34, as shown in FIG.
As shown in the block diagram of FIG. 3, among the target inter-vehicle distances L _TA L _TB L _TC output from the three types of target inter-vehicle distance calculation units 341, 342, and 343, the target inter-vehicle distance associated with the follow-up control mode 2 is selected. The target inter-vehicle distance L _TB calculated by the distance calculation unit B 342 is output from the tracking control mode switching unit 344 as the target inter-vehicle distance L _T to the vehicle speed control unit 36 and the like, as shown in FIG. 8.

Then, the engine output control device 9 or the like, to which the throttle opening command value is input, controls the braking / driving force so that the actual inter-vehicle distance L matches the target inter-vehicle distance L _T ,
When the preceding vehicle starts, the own vehicle starts accelerating more greatly than the preceding vehicle so that the inter-vehicle distance L between the own vehicle and the preceding vehicle becomes a value smaller than that when the preceding vehicle stops. It is possible to prevent the occupant from feeling uncomfortable as it is left behind.

As described above, in this embodiment, the target inter-vehicle distance L _T is calculated by using the function in which the time change rate of the target inter-vehicle distance L _TB becomes negative in the initial stage of starting. The vehicle will start accelerating more greatly than the preceding vehicle, and it is possible to prevent the passenger from feeling uncomfortable when the preceding vehicle starts to leave the vehicle.

[0065] Further, as shown in FIG. 9, the target inter-vehicle distance L time coefficient representing a rate of change α _T, then the inter-vehicle distance when the vehicle is stopped L _o and the minimum inter-vehicle distance L vehicle represents the difference between the _min distance deviation [Delta] L _{o #min}
Since it is set to a large value according to the size of
As shown in 0, when the inter-vehicle distance is large and the risk that the host vehicle approaches the preceding vehicle is small, the host vehicle accelerates to a greater extent and starts moving. It is possible to effectively suppress and prevent giving.

Further, the eyes calculated using the inverse response filter
Vehicle distance L_TBThe minimum distance L_{mi n}To limit
When the preceding vehicle starts, the own vehicle is larger than the preceding vehicle.
Even if you start at a speed
_minThe driver feels uncomfortable without getting closer than
Can be effectively suppressed and prevented. Also,
The above flow is repeatedly executed to accelerate the host vehicle.
The target inter-vehicle distance calculated by the target inter-vehicle distance calculation unit 34
Distance L_TIs the inter-vehicle distance command value L^*To match. Then,
When the processing of the tracking control mode selection unit 32 is executed,
As shown in the flowchart of FIG. 3, steps S1 and
The determination in S8 is “No”, and the determination in S9 is
Is set to “Yes”, and the tracking control mode is set in step S10.
Follow-up control mode 0 is selected as the type of mode. That
In the target inter-vehicle distance calculation unit 34, the block diagram of FIG.
As shown, three types of target inter-vehicle distance calculation units 341, 34
Target inter-vehicle distance L output from 2, 343_TOut of
The target inter-vehicle distance corresponding to the tracking control mode 0.
Target inter-vehicle distance L calculated by the separation calculation unit C343 _TCBut the figure
11, the tracking control mode switching unit 344
Target distance L_TAs the target vehicle distance to the vehicle speed control unit 36, etc.
Distance L_TIs output as.

Then, the engine output control device 9 or the like, to which the throttle opening command value is input, controls the braking / driving force so that the actual inter-vehicle distance L matches the target inter-vehicle distance L _T ,
When the inter-vehicle distance L between the host vehicle and the preceding vehicle is set to the same value as the inter-vehicle distance command value L ^* and, for example, the preceding vehicle accelerates, the own vehicle also accelerates with the same or a slight delay as the preceding vehicle. It is possible to ensure the following ability of the host vehicle with respect to acceleration and deceleration of the preceding vehicle.

On the other hand, while the above flow is repeatedly executed to accelerate the host vehicle, before the target inter-vehicle distance L _T calculated by the target inter-vehicle distance calculation unit 34 matches the inter-vehicle distance command value L ^* , It is assumed that a traffic jam occurs again and the preceding vehicle slows down. Then, when the process of the follow-up control mode selection unit 32 is executed, as shown in the flowchart of FIG. 3, the determination in step S8 is “Yes” through step S1, and in step S10, the type of the follow-up control mode is selected. Following control mode 0 is selected as.

As described above, in this embodiment, when the preceding vehicle starts decelerating, the target inter-vehicle distance L _T is set by using a function having a relatively quick response characteristic. The inter-vehicle distance L between the vehicle and the preceding vehicle is immediately controlled to a value according to the deceleration situation of the preceding vehicle, and the own vehicle is prevented from approaching the preceding vehicle, and the driver is prevented from feeling uncomfortable. It can be prevented.

In the above embodiment, the inter-vehicle distance sensor 12 corresponds to the inter-vehicle distance detecting means and the relative vehicle speed detecting means, and the inter-vehicle distance command value calculating section 31 corresponds to the inter-vehicle distance command value setting means. The distance calculation unit 34 corresponds to the target inter-vehicle distance setting means, and the vehicle speed command value calculation unit 35 and the vehicle speed control unit 36 correspond to the braking / driving force control device. Further, the above-described embodiment shows an example of the preceding vehicle following control device of the present invention, and does not limit the configuration of the device.

In the above embodiment, the case where the present invention is applied to the rear-wheel drive vehicle has been described, but the present invention can also be applied to the front-wheel drive vehicle, and the engine 2 is applied as the rotary drive source. Although the case has been described, the present invention is not limited to this, and an electric motor can be applied, and further, the present invention can be applied to a hybrid vehicle using an engine and an electric motor.

Further, in the above-described embodiment, the case where the laser radar is applied as the inter-vehicle distance sensor 12 has been described, but the present invention is not limited to this, a millimeter wave radar may be applied, and a CCD may be used. You may make it image-process the image pick-up of the used stereo camera and ask for a following distance. Furthermore, a case has been described in which the tracking control controller 20 is configured by a discrete digital system such as a microcomputer, but the present invention is not limited to this, and electronic circuits such as a function generator, a comparator, and a computing unit. You may make it comprise combining.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a preceding vehicle tracking control device of the present invention.

FIG. 2 is a block diagram showing a specific configuration of a follow-up process executed by the follow-up control controller of FIG.

FIG. 3 is a flowchart showing a specific example of processing of a tracking control mode selection unit in FIG.

FIG. 4 is a block diagram showing a specific example of processing of a target inter-vehicle distance calculation unit in FIG.

FIG. 5 is a graph showing a time change of a target inter-vehicle distance calculated using a filter including a dead time element.

FIG. 6 is a characteristic diagram showing an example of a map of the dead time with respect to the deviation rate.

FIG. 7 is a graph showing a simulation result of a change in a target inter-vehicle distance over time, in which the dead time is changed.

FIG. 8 is a graph showing a change over time in a target inter-vehicle distance calculated using an inverse response filter.

FIG. 9 is a characteristic diagram showing an example of a map of coefficients with respect to an inter-vehicle distance deviation.

FIG. 10 is a graph showing a result of a simulation of a change in a target inter-vehicle distance over time, in which a coefficient is changed.

FIG. 11 is a graph showing a change over time in a target inter-vehicle distance calculated using a second-order lag type filter.

FIG. 12 is an explanatory diagram for explaining an operating condition of the present embodiment.

[Explanation of symbols]

1FL and 1FR are front wheels 1RL and 1RR are rear wheels 2 is the engine 3 is an automatic transmission 4 is a propeller shaft 5 is the final reduction gear 6 is the axle 9 is an engine output control device 10 is a throttle actuator 11 is a transmission control device 12 is an inter-vehicle distance sensor 13 is a vehicle speed sensor 20 is a controller for tracking control

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B60R 21/00 B60R 21/00 624G 627 627 B60T 7/12 B60T 7/12 F F02D 29/02 301 F02D 29 / 02 301D G08G 1/16 G08G 1/16 CE (72) Inventor Akira Higashimata No. 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Nissan Motor Co., Ltd. F-term (reference) 3D041 AA30 AA41 AA79 AB01 AC01 AC15 AC26 AD51 AE02 AE41 AE45 AF01 3D044 AA01 AA11 AA21 AA25 AA45 AB01 AC02 AC15 AC24 AC59 AD04 AD16 AD21 AE04 AE21 3D046 BB18 GG02 GG06 HH20 HH22 JJ00 JJ05 JJ24 AK24 FA04 DB01 A04 BA05 DB06 BB04 DB05 BA06 DB01 DB01 DB04 DB01 BA05 DB06 BA01 DB04 BA05 DB23 BB06

Claims (8)

[Claims] 1. An inter-vehicle distance detecting means for detecting an inter-vehicle distance between a host vehicle and a preceding vehicle, an inter-vehicle distance command value setting means for setting a predetermined inter-vehicle distance command value, and an inter-vehicle distance detecting means. Target inter-vehicle distance setting means for setting a target inter-vehicle distance using a predetermined function based on the inter-vehicle distance and the inter-vehicle distance command value set by the inter-vehicle distance command value setting means, and the target set by the target inter-vehicle distance setting means And a braking / driving force control means for controlling the braking / driving force so that the inter-vehicle distance detected by the inter-vehicle distance detecting means coincides with the inter-vehicle distance, and the target inter-vehicle distance setting means, when the host vehicle is stopped, When the inter-vehicle distance detected by the inter-vehicle distance detecting means is smaller than the inter-vehicle distance command value set by the inter-vehicle distance command value setting means, the target inter-vehicle distance is set by using a function having a slow response characteristic. Line vehicle slave control devices. 2. The preceding vehicle tracking control device according to claim 1, wherein the function having a slow response characteristic includes a function representing a dead time. 3. The dead time is set large in accordance with the magnitude of the difference between the inter-vehicle distance detected by the inter-vehicle distance detecting means when the vehicle is stopped and the inter-vehicle distance command value set by the inter-vehicle distance command value setting means. The preceding vehicle following control device according to claim 2. 4. The preceding vehicle follow-up control device according to claim 1, wherein the function having a slow response characteristic is a function in which a temporal change rate of a target inter-vehicle distance in an initial stage of starting is negative. 5. The preceding vehicle follow-up control device according to claim 4, wherein the time change rate of the target inter-vehicle distance at the initial stage of the start is set to be large in accordance with the size of the inter-vehicle distance when the vehicle is stopped. . 6. The preceding vehicle following according to claim 1, wherein the target inter-vehicle distance setting means regulates the target inter-vehicle distance calculated by a function having a slow response characteristic to a predetermined minimum inter-vehicle distance. Control device. 7. The target inter-vehicle distance setting means sets the target inter-vehicle distance using a function having a slow response characteristic until the target inter-vehicle distance matches the inter-vehicle distance command value set by the inter-vehicle distance command value setting means. The preceding vehicle slave control device according to any one of claims 1 to 6, wherein: 8. A relative vehicle speed detecting means for detecting a relative vehicle speed between the own vehicle and a preceding vehicle, wherein the target inter-vehicle distance setting means is a target until the relative vehicle speed detected by the relative vehicle speed detecting means becomes negative. The preceding vehicle slave control device according to any one of claims 1 to 7, wherein the inter-vehicle distance is set by using a function having a slow response characteristic.