JPH04244434A - Traveling controller for vehicle - Google Patents

Abstract

PURPOSE:To obtain sufficient following up of forward vehicle in traveling in places where there is much traffic and smooth driving feeling without jerky feeling in traveling in places where there is little traffic by traveling control. CONSTITUTION:A traveling controller for vehicles is provided with a traffic volume judging means 20 for judging traffic volume and control gain adjusting means 21 for enlarging control gain to control the distance between vehicles when it is judged that there is more traffic than the specified traffic volume by the traffic volume judging means 20. When there is much traffic, sufficient following-up performance to the forward vehicle can be obtained by enlarging control gain and improving control response. When there is little traffic, calm traveling without jerky feeling is realized by reducing control gain and lowering control response.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a vehicle travel control device, and more specifically, vehicle speed control that automatically adjusts the vehicle travel speed to a set target vehicle speed and maintaining a constant distance between the vehicle and the vehicle traveling in front. The present invention relates to a vehicle travel control device that performs inter-vehicle distance control.

0002

2. Description of the Related Art Vehicles such as automobiles are now equipped with vehicle cruise control devices called auto-cruise devices that allow drivers to set the speed of the vehicle as they wish. This device is equipped with a set switch to set a target vehicle speed and increase the speed, a coast switch to decelerate, and a resume switch to return to the vehicle speed under conventional constant speed driving control. The vehicle speed can be set or changed at will. For example, if the set switch is turned on while the vehicle is driving, it is possible to shift to constant speed driving control with the vehicle speed at that time set as the set vehicle speed. If you want to increase the speed while driving at a constant speed, keep the set switch turned on to increase the vehicle speed, and turn it off to control the vehicle at a constant speed using the set speed. It can be migrated. On the other hand, when you want to decelerate, by continuing to turn on the coast switch, you can decelerate during that time, and when you turn it off, the vehicle shifts to constant speed driving control with the vehicle speed at that point set as the set vehicle speed. Furthermore, when the resume switch is turned on, the speed can be returned to the speed set during constant speed driving. Therefore, the driver can drive the vehicle at a constant speed on a highway or the like by simply manually operating the switch without operating the accelerator pedal. Furthermore, a so-called inter-vehicle distance auto-cruise system has been adopted which not only performs such constant speed driving control but also performs inter-vehicle distance control that maintains the inter-vehicle distance to a target constant value from the vehicle traveling in front. Sometimes. By the way, JP-A-61-6
Publication No. 031 describes an inter-vehicle distance control device that is capable of adjusting an inter-vehicle distance depending on driving conditions and achieves a desired inter-vehicle distance with appropriate acceleration/deceleration.

0003

By the way, in a vehicle equipped with an auto-cruise device for inter-vehicle distance, it is desirable to be able to obtain appropriate followability and running feeling depending on the traffic volume at that time. In other words, when the traffic volume is heavy, the distance closing function and the distance widening function are improved to enable sufficient following of the vehicle traveling in front, and when the traffic volume is light, unnecessary following is avoided. , it is preferable to eliminate the jerky feeling. This followability is related to the control responsiveness for controlling the inter-vehicle distance, and increasing the control responsiveness improves the followability. However, in the above-mentioned known technology, it is not possible to relatively change or adjust such control responsiveness depending on the traffic volume. The present invention has been made in consideration of these circumstances, and its purpose is to improve the tracking performance so that it is possible to sufficiently follow the vehicle traveling in front when the traffic volume is heavy, while at the same time improving the following performance when the traffic volume is low. It is an object of the present invention to provide a travel control device for a vehicle that avoids unnecessary following in some cases and enables traveling without a jerky feeling.

0004

[Means for Solving the Problems] The present invention provides an inter-vehicle distance detecting means for detecting an inter-vehicle distance to a vehicle traveling in front, and an inter-vehicle distance detecting means for detecting an inter-vehicle distance to a vehicle traveling in front, and an inter-vehicle distance detecting means for detecting an inter-vehicle distance to a vehicle traveling in front, and an inter-vehicle distance that controls the inter-vehicle distance to a target vehicle. The present invention is applied to a vehicle travel control device including a control means. Its features include a traffic volume determination means for determining the traffic volume, and when the traffic volume determination means determines that the traffic volume is greater than a predetermined value, the following distance control means performs inter-vehicle distance control. control gain adjusting means is provided for instructing the vehicle to increase the control gain of the vehicle so as to improve followability for maintaining the following distance.

[0005]

[Operation] The traffic volume determination means determines whether the traffic volume is more or less, and if it is determined that the traffic volume is greater than or equal to a predetermined value, the control gain adjustment means changes the control gain for inter-vehicle distance control to a larger value. be done. As a result, when the traffic volume is heavy, the control responsiveness for controlling the inter-vehicle distance is improved, and it becomes possible to sufficiently follow the vehicle traveling in front. On the other hand, when the traffic volume is low, the control gain is reduced,
There is no unnecessary following, and driving is achieved without a jerky feeling.

[0006]

Effects of the Invention The vehicle running control device of the present invention includes a traffic flow determining means for determining the traffic volume, and an inter-vehicle distance control means when the traffic volume determining means determines that the traffic volume is equal to or higher than a predetermined value. control gain adjustment means for increasing the control gain for controlling the inter-vehicle distance by
When the traffic volume is heavy, increasing the control gain will improve control responsiveness and provide sufficient follow-up performance to maintain the following distance, such as closing or widening the gap to the vehicle in front. can. On the other hand, when the traffic volume is small, the control gain is conversely reduced, reducing control responsiveness to avoid unnecessary following, and achieving driving control without a jerky feeling.

[0007]

EXAMPLES The present invention will be explained in detail below based on examples thereof. The vehicle running control device shown in this example performs both so-called inter-vehicle distance control and vehicle speed control, and in order to be able to sufficiently follow the vehicle traveling in front, especially when the traffic is heavy, the following measures are taken. It consists of As shown in FIG. 1, a control unit 1 consisting of a microcomputer includes a calculation section 2 that performs various calculations for vehicle distance control and vehicle speed control, a storage section 3 that stores programs necessary for the calculations, and an input/output section. A circuit (not shown) is provided. On the input side, there is a set switch 4 as a target vehicle speed setting means for setting a target vehicle speed, a coast switch 5 as a deceleration operation means for decelerating the set vehicle speed set by the set switch 4, and a coast switch 5 as a deceleration operation means for decelerating the set vehicle speed set by the set switch 4. a resume switch 6 for returning the vehicle speed to the one at the time of control; inter-vehicle distance detection means 7 for detecting the inter-vehicle distance to the vehicle traveling in front;
A vehicle speed sensor 8, a brake switch 9, an accelerator position sensor 10, a gear position sensor 11, and a mode switch 12 are connected. On the other hand, a step motor 22 serving as an actuator for operating a throttle valve 23 is connected to the output side. The circuit in the calculation unit 2 includes a throttle control means 14, a vehicle load detection means 17 for detecting the load condition of the vehicle, and an inter-vehicle distance detection means 7.
This is a driving control in which the distance between the vehicle and the vehicle in front, which is detected by Inter-vehicle distance control means 1
9. Traffic flow determining means 20 for determining the traffic volume; when the traffic volume determining means 20 determines that the traffic volume is greater than a predetermined value, a control gain K for inter-vehicle distance control performed by the inter-vehicle distance control means 19; A control gain adjusting means 21 is provided for instructing the vehicle to increase the follow-up performance for maintaining the inter-vehicle distance. The traffic volume determining means 20 detects the amount of traffic by counting the number of times the vehicle distance control and vehicle speed control are switched within a predetermined period of time. The control gain adjusting means 21 obtains the control gain K corresponding to the traffic volume count number from the map stored in the storage unit 3 in advance (see step 66 in FIG. 6), and applies this to the vehicle speed control using the PIPD control. It is intended to be reflected. As a result, when the traffic volume is heavy, the control gain K is increased, improving the control responsiveness for distance control and making it possible to sufficiently follow the vehicle traveling ahead, while when the traffic volume is low, the control gain K is increased. , the jerkiness can be eliminated without unnecessary tracking by lowering the control gain K. The control gain K is used to correct the control output for throttle control performed by the throttle control circuit 14 during normal driving. In the throttle control circuit 14, the basic throttle opening f( α) is
It is determined in accordance with the accelerator opening degree α at that time. The map is prepared for each mode, that is, power, economy, normal, and 1st, 2nd, 3rd, and 4th gear.
In order of speed, throttle opening f(
α), that is, the throttle gain is set to be large. As a result, as the speed increases, the throttle opening degree f(α) is increased to increase the engine output, and a good response can be obtained. Next, a coefficient K1 is calculated for correcting the basic throttle opening degree f(α) obtained as described above with respect to the accelerator pedal depression speed β. As shown in FIG. 9, this coefficient K1 is obtained corresponding to the accelerator pedal depression speed β.
The larger the value, the larger the value. This takes the accelerator pedal depression speed β as an expression of the driver's intention, and determines that the larger the value, the faster the driver wants to accelerate, and obtains a throttle control output that increases the throttle opening f(α). It is for. In addition, in FIG. 9, the horizontal axis shows the accelerator pedal depression time that is converted in accordance with the case where the accelerator opening degree α goes from 0 to fully open. The time is 500 μsec at point Q and 200 μsec at point R, and the value of the coefficient K1 corresponding to the accelerator pedal depression speed β in that range is shown on the vertical axis. Note that this accelerator pedal depression speed β is based on the accelerator opening degree α detected by the accelerator position sensor 5.
It is obtained by dividing the time required to press the accelerator pedal. Furthermore, the throttle opening f(α
) is calculated according to the vehicle speed V at that time. This coefficient K2 is obtained corresponding to the vehicle speed V at that time, as shown in FIG.
Above 0 km/h, the value increases as the vehicle speed V increases. This is in order to further increase the throttle gain in response to the increasing running resistance as the vehicle speed V increases, and to increase the engine output through good engine revving, thereby providing a responsive driving feeling. In the throttle control circuit 14, the above two coefficients K1 and K2 are
Further, as described above, the throttle opening f is adjusted by taking into account the control gain K set by the control gain adjusting means 21.
(α) is performed, and a throttle control output TH corresponding to the correction value is sent to the step motor 22 that drives the throttle valve 23. As a result, the driving feeling can be adjusted according to the traffic volume, and a good driving feeling can always be obtained regardless of the traffic conditions. In other words, the control gain K obtained according to the traffic volume at that time is reflected in the distance control and vehicle speed control in auto cruise, so that when the traffic volume is heavy, acceleration and deceleration are made favorable and sufficient control is applied to the vehicle traveling ahead. This enables accurate tracking. on the other hand,
When the traffic volume is small, the control gain K is lowered to avoid unnecessary following, thereby eliminating the jerky feeling. The control gain K is also reflected in normal throttle control to adjust the driving feel according to the traffic volume at that time. In other words, when there is a lot of traffic, the acceleration and deceleration are made good, and when the amount of traffic is light, the response is slightly lowered so that a driving feeling with gentle speed changes can be obtained.

[0008] A basic preferred example of travel control by the present device will be explained in detail below, step by step, based on the flowcharts shown in FIGS. 2 to 8. First, regarding throttle control, the accelerator opening degree α is read by the accelerator position sensor 10 [S1], and the vehicle speed V is also read by the vehicle speed sensor 8 [S2]. Furthermore, the gear position G of the shift lever is read by the gear position sensor 11 [S3], and the mode M at that time is read by the mode switch 12 [S4]. Thereafter, the throttle control circuit 14 reads out the throttle opening f(α) relative to the accelerator opening α from the steady map corresponding to the mode M at that time [S5]. Next, a correction coefficient K1 for correcting the throttle opening degree f(α) with respect to the accelerator pedal depression speed β at that time is calculated [S6], and a correction coefficient K2 for correcting the vehicle speed is also calculated [S6]. S7]. As will be described later, a correction value TH of the throttle opening f(α) is calculated in consideration of the control gain K determined by the control gain adjusting means 21 [S8],
A throttle control output corresponding to this TH is sent to the step motor 22 [S9]. As a result, as will be described later, throttle control is performed that takes into account the adjustment of the control gain K depending on the traffic volume. When the traffic volume is heavy, the control gain K is increased to improve acceleration and deceleration, and when the traffic volume is low, the control gain K is increased. When this happens, the response is slightly reduced to give a smoother driving feel. Regarding auto speed control, as shown in step 11 of Fig. 3, first, a steady map (Fig. 1
1) is read out from the storage unit 3, and it is determined whether the throttle opening f(α) at that time is larger than the steady throttle opening shown in the steady map (indicated by the solid line P in FIG. 11). [S12]. If the throttle opening f(α) at that time is larger than the steady throttle opening,
It is determined that the load is heavy due to the uphill slope or the large number of passengers, and the ZONE flag is set to 1 [S13]. That is, the vehicle load detection circuit 17 detects the load state at that time. On the other hand, the throttle opening f at that time
If (α) is smaller than the steady throttle opening, that is, if the slope is downward, the ZONE flag is reset to 0 [S14]. Next, when the brake switch 9 is turned on [S15], the vehicle speed control is canceled and the set flag is set to 1 [S16]. Step 15
If the brake switch 9 is not on, the accelerator position sensor 10 asks whether the accelerator opening is fully closed [S17], and if it is fully closed, the process moves to step 18 in FIG. When the set switch 4 is turned on, the set V is replaced with the vehicle speed VSP at that time.
S19], the time the set switch 4 is on is 0
．． If it is longer than 5 seconds [S20], based on the acceleration map stored in the storage unit 3 (see FIG. 12), a control output is provided to the step motor 22 so that the throttle opening is adjusted according to the vehicle speed at that time. is sent out and accelerated [S21
]. That is, as shown in FIG. 12, the slot opening degree is set to increase gradually in proportion to the vehicle speed at speeds of 40 km/h or higher. In step 20, if the set switch 4 is turned on for less than 0.5 seconds, the process moves to FIG. 5, where inter-vehicle distance control by PIPD control and vehicle speed control by PID control are performed together. That is, the coast flag is set to 1 [S22], and the ZO
If the NE flag is 1 [S23], the throttle opening setting circuit 18 sets the steady throttle opening (line P in FIG. 11) according to the vehicle speed at least at the end of the deceleration operation.
), a control output is sent to the step motor 22 [S24], and then the coast flag is reset to 0 [S25], and inter-vehicle distance control by PIPD control and vehicle speed control by PID control are performed together. Transition to inter-vehicle distance control/vehicle speed control [S26]. Thereby, sufficient engine output can be ensured [S24] and smooth transient response can be obtained without having to fully close the throttle opening during the transition period as in the conventional case. In other words, even when a load is required such as on an uphill slope, the vehicle does not feel stalled after the coast switch 5 is turned on, and smooth inter-vehicle distance control and vehicle speed control can be achieved. As shown in FIG. 6, inter-vehicle distance control and vehicle speed control are performed until the time has elapsed for 5 minutes [S51].
When P is smaller than set V [S52] and the distance between the vehicle and the vehicle traveling ahead at that time is within 30 m [
S53], if the inter-vehicle distance flag is not set to 1 [
S54], and 1 is added to the count [S55]. Then, the inter-vehicle distance flag is set to 1 [S56], and PIPD control for inter-vehicle distance control is performed [S58]. In other words,
When the distance between the vehicle and the vehicle traveling in front becomes less than 30 meters, distance control is started. If the inter-vehicle distance flag is set to 1 in step 54, immediately step 57
After transitioning to and the coast flag is reset to 0 [
S57], PIPD control is entered [S58]. Then, as will be described later, the control gain adjusting means 2 adjusts the throttle opening TH1 determined by this PIPD control.
By multiplying the control gain K obtained by 1,
The throttle opening TH is determined [S59]. That TH
A throttle control output corresponding to is sent to the step motor 22 [S60], and inter-vehicle distance auto-cruise control is performed to maintain a predetermined inter-vehicle distance. Incidentally, in PIPD control, as shown in FIG. 8, first, the current inter-vehicle distance DIS is subtracted from the target inter-vehicle distance set DIS, and the difference value ENV is calculated [S
71]. Next, integral gain KI, proportional gain KP1,
From the arithmetic expression using KP2 and the differential gain KD, the TG value for obtaining the throttle opening TH1 to be included in the arithmetic expression in step 59 is determined [S72 and S74]. Note that at this time, the current ENV, DIS1, and DIS are E
It is replaced with NV1, DIS2, and DIS1 and prepared for the next calculation [S73]. On the other hand, in step 53 of FIG. 6, when the distance between the vehicle and the vehicle in front becomes 30 m or more, it is asked whether the coast flag is set to 1 [S61], and if it is not set, the vehicle speed is controlled. Determine, add 1 to the count [S62]
, sets the coast flag to 1 [S63]. and,
After resetting the distance flag to 0 [S64], the normal P
Vehicle speed control is performed by ID control [S6
5]. Then, after the time has elapsed for 5 minutes [S51], the map for determining the control gain K corresponding to the count number of the vehicle distance control and vehicle speed control is displayed in the control gain adjusting means 2.
1 is read out from the storage unit 3, and the control gain K is determined [S66]. Thereafter, the count and time are reset to 0 [S67]. As shown in the map, the control gain K obtained by the control gain adjustment means 21 takes a large value when the traffic volume is large, and the control gain K obtained by the control gain adjustment means 21 takes a large value when the traffic volume is large.
, and each calculation formula in step 8 (see FIG. 2) in throttle control. Therefore, in auto speed control, when the traffic volume is heavy, the control gain K increases, so the acceleration/deceleration function is improved and it is possible to sufficiently follow the vehicle in front, while the traffic volume is relatively low. Sometimes, without unnecessary follow-up,
It is possible to achieve a gentle running state without a so-called jerky feeling. In addition, in throttle control, good drivability is achieved by changing control responsiveness according to traffic volume. In step 18 of FIG. 4, if the set switch 4 is not turned on, the process moves to step 31,
If the coast switch 5 is turned on, the throttle is fully closed [S32] and the vehicle speed VSP at that time is set to set V.
is replaced [S33], and the coast flag is set to 1 [S34]. In step 31, if the coast switch 5 is not turned on, the process moves to step 35 in FIG. 7, and if the set flag is 1, that is, if the auto cruise control is canceled and the resume switch 6 is turned on. [S36], the resume flag is set to 1 [S37]. After that, if the vehicle speed VSP at that time is not larger than the set V-2Km/h [S38], the throttle opening output corresponding to the vehicle speed VSP at that time is obtained from the acceleration map (see FIG. 12) and the acceleration is performed. is done [S39]. Note that even if the resume switch 6 is not turned on in step 36, if the resume flag is set to 1 [S40], the process moves to step 38. On the other hand, if the set flag is not set to 1 in step 35 or the resume flag is not set to 1 in step 40,
Then, the above-mentioned vehicle distance control and vehicle speed control are performed [S26]. Incidentally, in step 38 (see FIG. 7), if the vehicle speed VSP at that time is greater than the set V-2 Km/h, after resetting the resume flag to 0,
S41], the process moves to FIG. As described above, according to this example, in auto speed control, the control response is changed by adjusting the control gain K according to the traffic volume at that time, and when the traffic volume is heavy, sufficient tracking is achieved. On the other hand, when the traffic volume is low, it is possible to obtain a smooth driving feeling without a jerky feeling without unnecessary following. Furthermore, by reflecting the control gain K in the normal throttle control, good responsiveness according to the traffic volume can be obtained and the driving feeling can be improved.

As described above, according to the vehicle running control device of the present invention, when the traffic volume determination means determines the traffic volume and the traffic volume determination means determines that the traffic volume is equal to or higher than a predetermined value, Since a control gain adjustment means for increasing the control gain for controlling the inter-vehicle distance is provided, when the traffic volume is heavy, the control gain K increases, improving control responsiveness for controlling the inter-vehicle distance, and driving forward. The tracking performance for maintaining the distance between vehicles, such as the function to close the distance between vehicles and the function to widen the distance between vehicles, is enhanced. On the other hand, when the traffic volume is small, the control gain is reduced to reduce control responsiveness, and it is possible to achieve a gentle running state without any jerky feeling without unnecessary tracking.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram of a vehicle travel control device according to the present invention.

FIG. 2 is a part of a flowchart for explaining throttle control in constant speed driving control.

FIG. 3 is a part of a flowchart for explaining auto speed control in travel control.

FIG. 4 is a flowchart following FIG. 3 explaining auto speed control in travel control.

FIG. 5 is a flowchart following FIG. 4 explaining auto speed control in travel control.

FIG. 6 is a flowchart for explaining vehicle distance control and vehicle speed control in travel control.

FIG. 7 is a flowchart following FIG. 4 explaining auto speed control in travel control.

FIG. 8 is a flowchart illustrating PIPD control in travel control.

FIG. 9 is a map for determining the correction coefficient K1 of the throttle opening based on the accelerator pedal depression speed.

FIG. 10 is a map for determining a vehicle speed correction coefficient K2 for throttle opening.

FIG. 11 is a steady map showing the throttle opening degree corresponding to the vehicle speed for also detecting the load state of the vehicle.

FIG. 12 is an acceleration map showing the correspondence between vehicle speed and throttle opening during acceleration.

[Explanation of symbols]

7... Inter-vehicle distance detection means, 19... Inter-vehicle distance control means, 20
...Traffic volume determining means, 21...Control gain adjusting means.

Claims (1)

[Claims] [Claim 1] For a vehicle, comprising an inter-vehicle distance detection means for detecting an inter-vehicle distance to a vehicle running ahead, and an inter-vehicle distance control means for controlling an inter-vehicle distance to a vehicle running ahead to a target inter-vehicle distance. In the travel control device, there is a traffic flow determining means for determining the traffic volume, and when the traffic volume determining means determines that the traffic volume is equal to or higher than a predetermined value, the following distance control means is configured to perform inter-vehicle distance control by the inter-vehicle distance control means. 1. A vehicle travel control device, comprising: a control gain adjustment means for increasing a control gain to increase followability for maintaining an inter-vehicle distance.