JP4424387B2 - Travel control device - Google Patents

Description

  The present invention relates to a travel control device that controls the travel speed of a vehicle.

Conventionally, follow-up running control that keeps the inter-vehicle distance is performed for the preceding vehicle traveling in the same lane as the own vehicle, and when the preceding vehicle stops, stop control is performed so that the distance from the stopped preceding vehicle is constant. There is a travel control device to perform. As such a travel control device, for example, there is a follow-up travel device disclosed in Japanese Patent Laid-Open No. 2001-225669. In this follow-up travel device, when the vehicle speed is medium or high speed traveling above a predetermined speed, the inter-vehicle time, which is the time difference until the vehicle reaches the preceding vehicle, is maintained above the target time. In addition, at a low speed less than a predetermined speed, acceleration / deceleration control is performed in proportion to the deviation between the distance between the own vehicle and the preceding vehicle and the minimum distance between the vehicles set as not approaching the preceding vehicle any more. Is.
JP 2001-225669 A

  However, the technique disclosed in Patent Document 1 differs in control at medium and high speeds and at low speeds. For this reason, for example, when there is a sudden change in acceleration between different controls such as follow-up control and stop control, the vehicle may suddenly accelerate or decelerate at a predetermined speed, reducing the ride comfort for the occupant. There was a possibility of inviting. In addition, when the driver stops the vehicle during normal driving, the driver often puts a light “unplug” just before the stop. However, in the above-described follow-up traveling device, such “unplugging” is not taken into consideration, and thus there is a possibility that the driver when stopping the host vehicle may feel a sense of incongruity different from a normal feeling.

  Therefore, the problem of the present invention is to prevent the ride comfort of the occupant from deteriorating even when different control such as follow-up running control and stop control is performed according to the vehicle speed and the like, and the driver drives immediately before stopping. An object of the present invention is to provide a travel control device capable of performing control close to a sense.

The travel control device according to the present invention that has solved the above-described problems performs follow-up travel control for controlling the acceleration / deceleration of the host vehicle so as to maintain the inter-vehicle distance with respect to the preceding vehicle traveling in the same lane as the host vehicle. When the vehicle stops, the vehicle starts decelerating at a predetermined acceleration / deceleration initial value, and stops from the follow-up drive control in the travel control device that performs stop control to stop the vehicle at a position where the distance from the preceding vehicle is constant. When shifting to control, if the requested acceleration / deceleration current value, which is the requested acceleration / deceleration at the time of transition, is smaller than the initial acceleration / deceleration value, the acceleration / deceleration calculated by the follow-up running control is continued until the predetermined timing is reached. After the predetermined timing, control is performed to reduce the magnitude of the acceleration / deceleration of the own vehicle.

  In the travel control device according to the present invention, when the follow-up travel control is shifted to the stop control, the acceleration / deceleration calculated by the follow-up travel control is continued until the predetermined timing is reached after the shift to the stop control. Is controlling. For this reason, the acceleration / deceleration can be linearly shifted between the follow-up running control and the stop control, so that the ride comfort of the occupant due to the nonlinear acceleration change can be prevented.

  Moreover, in the travel control device according to the present invention, the acceleration / deceleration of the host vehicle is controlled so that the host vehicle is stopped at a position where the distance from the preceding vehicle is constant after a predetermined timing. For this reason, immediately before the own vehicle stops, the deceleration of the own vehicle becomes small, and it is possible to make the state close to the state of “unplugging” performed by the normal driver. Therefore, it is possible to perform control close to the feeling of driving by the driver immediately before stopping.

  Furthermore, when shifting from follow-up running control to stop control, compared to the case of controlling the acceleration / deceleration of the vehicle so that the vehicle stops at a position where the distance from the preceding vehicle is constant at the same time as the shift to the stop control. The host vehicle is decelerating with a large acceleration / deceleration. For this reason, it is possible to secure a margin for distance for performing the “pull out” control.

  Here, the predetermined timing is that after controlling the acceleration / deceleration of the host vehicle so as to maintain the inter-vehicle distance with respect to the preceding vehicle, the host vehicle is adjusted so that the host vehicle is stopped at a position where the distance from the preceding vehicle is constant. When the vehicle's acceleration / deceleration is controlled to stop the vehicle at a position where the distance between the vehicle and the preceding vehicle after shifting to stop control is constant after the speed is controlled It is possible to adopt a mode in which the travel distance is the same.

  By setting such a predetermined timing, in the stop control, the acceleration / deceleration of the host vehicle is controlled so as to keep the inter-vehicle distance from the preceding vehicle until the predetermined timing is reached after the shift to the stop control. Even if the acceleration / deceleration of the host vehicle is controlled so that the host vehicle is stopped at a position where the distance from the preceding vehicle is constant, the own vehicle is maintained so that the inter-vehicle distance is maintained with respect to the preceding vehicle. After controlling the acceleration / deceleration of the vehicle, stop the vehicle at a stop position equivalent to the stop position when controlling the acceleration / deceleration of the vehicle so that the vehicle stops at a position where the distance from the preceding vehicle is constant. Can do.

  Further, the predetermined timing may be determined based on the vehicle speed of the host vehicle.

  Thus, the predetermined timing can be easily determined by determining the predetermined timing based on the vehicle speed of the host vehicle.

  Furthermore, the predetermined timing can be an aspect in which the vehicle speed of the host vehicle becomes the vehicle speed Vc obtained by the following equation (6).

Vc = 2 × (Gds−Gdn) · Vs / (Gs−Gdn) (6)
However, Gds: acceleration / deceleration when controlling the host vehicle so that the host vehicle is stopped at a position where the distance from the preceding vehicle is constant
Gdn: Acceleration / deceleration when controlling the host vehicle so as to maintain the inter-vehicle distance with respect to the preceding vehicle
Vs: Vehicle speed when stop control is started
Gs: Acceleration when the vehicle stops The predetermined timing can be determined without using complicated calculation such as integration by obtaining the predetermined timing based on such an expression.

  As described above, according to the present invention, even when different control such as follow-up running control and stop control is performed according to the vehicle speed and the like, the ride comfort of the occupant is not reduced, and the driver can It is possible to provide a travel control device capable of performing control close to the feeling of driving.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In each embodiment, portions having the same function are denoted by the same reference numerals, and redundant description may be omitted.

  FIG. 1 is a block diagram of a travel control apparatus according to an embodiment of the present invention. As shown in FIG. 1, the travel control apparatus 1 according to the present embodiment includes an inter-vehicle control ECU 11, an engine ECU 12, and a brake ECU 13. The inter-vehicle control ECU 11 includes a radar sensor 21 as an inter-vehicle distance sensor. The wheel speed sensor 22 and the G sensor 23 are connected.

  For example, the radar sensor 21 is attached to the front grille of the vehicle, measures the distance between the preceding vehicle traveling in front of the same lane and the host vehicle, converts the measured distance into a signal, and outputs the signal to the inter-vehicle control ECU 11 as a distance signal. To do. The wheel speed sensor 22 is attached to, for example, a traveling wheel of the vehicle, detects the vehicle speed of the host vehicle, converts the detected vehicle speed of the host vehicle into a signal, and outputs the signal to the travel control device 1 as a vehicle speed signal. The vehicle speed signal output to the travel control device 1 is transmitted to the inter-vehicle control ECU 11 through the brake ECU 13 by communication. The G sensor 23 detects the acceleration of the host vehicle, converts the detected acceleration into a signal, and outputs the signal to the travel control device 1 as an acceleration signal. The acceleration signal output to the travel control device 1 is transmitted to the inter-vehicle control ECU 11 through the brake ECU 13 by communication.

  The inter-vehicle control ECU 11 calculates the relative distance between the preceding vehicle and the host vehicle based on the distance signal output from the radar sensor 21 and the change in the vehicle speed signal output from the vehicle speed sensor 22. Then, based on the relative speed between the preceding vehicle and the host vehicle, the travel control amount of the host vehicle is calculated. In the inter-vehicle control ECU 11, the follow-up running control and the stop control are used together in calculating the running control amount. Details of these will be described later.

  The inter-vehicle control ECU 11 converts the calculated travel control amount into a signal, which is output to the engine ECU 12 and the brake ECU 13 as a travel control signal. The engine ECU 12 is connected to the electronic throttle 31 and calculates the throttle opening of the electronic throttle 31 based on the travel control signal output from the inter-vehicle control ECU 11. The throttle opening is converted into a signal and output to the electronic throttle 31 to adjust the throttle opening to a desired amount. The brake ECU 13 is connected to the brake actuator 32 and calculates the brake strength of the brake actuator 32 based on the travel control signal output from the inter-vehicle control ECU 11. The brake force is converted into a signal as a brake strength signal and output to the brake actuator 32, thereby adjusting the brake force to a desired amount.

  The operation / action of the travel control apparatus 1 according to the present embodiment having the above-described configuration will be described. Before that, an outline of control by the travel control apparatus 1 according to the present embodiment will be described.

  In the travel control device 1 according to the present embodiment, as shown in FIG. 2, the vehicle follows in accordance with the inter-vehicle distance D, the relative speed V, etc. between the preceding vehicle MP traveling on the same lane as the host vehicle MM and the host vehicle MM. Use running control and stop control properly. In the follow-up running control, the acceleration / deceleration is controlled so that the inter-vehicle distance D is kept constant with respect to the preceding vehicle MP. In the stop control, as the preceding vehicle MP stops, the deceleration is performed so that the host vehicle is stopped so that the distance from the preceding vehicle MP becomes a preset inter-vehicle distance at the time of stopping.

  While the vehicle is traveling at medium to high speed, the following traveling control is performed, and when the following traveling control is performed, the preceding vehicle stops or the required acceleration for the following traveling control becomes negative. Sometimes, shift to stop control. Even when the stop control is being performed, if the preceding vehicle has not stopped, or if the required acceleration / deceleration for the follow-up control has been positive for a predetermined number of times in the past, the process proceeds to the follow-up running control. .

  Based on these assumptions, a control procedure by the travel control device 1 according to the present embodiment will be described. FIG. 3 is a flowchart showing a procedure of traveling control by the traveling control apparatus according to the present embodiment.

  As shown in FIG. 3, when the control is started, first, the inter-vehicle control ECU 11 determines whether or not the preceding vehicle traveling in the same lane as the own vehicle is stopped (S1). When determining whether or not the preceding vehicle is stopped, the speed of the preceding vehicle is calculated based on the distance between the host vehicle and the preceding vehicle measured by the laser sensor 21. It can be set as the aspect which judges that the preceding vehicle has stopped if the time for which the speed of this preceding vehicle is less than a predetermined threshold value passes for a fixed time. Specifically, for example, when the time for which the speed of the preceding vehicle is 0.8 km / n has elapsed for 1 s, it is determined that the preceding vehicle has stopped.

  As described above, in this embodiment, it is determined that the preceding vehicle is stopped only from the speed of the preceding vehicle, but the vehicle speed of the preceding vehicle and the inter-vehicle distance between the preceding vehicle and the own vehicle are combined. It is also possible to adopt a mode in which stop determination is performed. In the vehicle stop determination here, in order to prevent frequent switching between the follow-up traveling control and the stop control, it is important to avoid erroneously determining that the vehicle is actually stopped but stopped. desirable.

  When it is determined that the preceding vehicle is stopped as a result of the stop determination of the preceding vehicle, whether the required acceleration when the follow-up control is performed is positive or negative, in other words, in the acceleration state or the deceleration state. It is determined whether there is (S2). Here, if the follow-up running control is performed as it is, it is determined whether the required acceleration / deceleration for the host vehicle calculated with respect to the control target is positive or negative.

  On the other hand, when it is determined in step S1 that the preceding vehicle has not stopped, the follow-up control is continued, the required acceleration for the vehicle for follow-up control is calculated, and output to the engine ECU 12 and the brake ECU 13 (S10).

  Subsequently, when it is determined in step S2 that the required acceleration is negative, the acceleration / deceleration calculation for the stop control is started, and the stop control calculation is performed to store the fact that the acceleration / deceleration calculation for the stop control is started. The flag is turned on (S3). If the calculation flag is turned ON, it is determined whether or not the previous value of the calculation flag is OFF (S4). As a result, if it is determined that the calculation flag is OFF, the acceleration / deceleration calculation for stop control has not been started previously. In this case, the control initial value of the control logic for stop control is set (S5).

  When performing stop control, it is assumed that the host vehicle is stopped so that the inter-vehicle distance between the preceding vehicle and the host vehicle becomes a predetermined set value, for example, 3.5 m. At this time, based on the distance between the current preceding vehicle and the host vehicle, the host vehicle speed, the host vehicle acceleration / deceleration, etc. Estimate the inter-vehicle distance, own vehicle speed, own vehicle acceleration / deceleration, etc.

  For example, as shown in FIG. 4 (a), the inter-vehicle distance Dn between the host vehicle MM and the preceding vehicle MP when starting the stop control causes a response delay, as shown in FIG. 4 (b). Assume that the inter-vehicle distance Ds between the host vehicle MM and the preceding vehicle MP is reached. Taking this response delay into account, stop control is performed.

As shown in the following equation (1), the vehicle speed Vs at the start of deceleration can be obtained by multiplying the current required acceleration / deceleration Gdn by the response delay time Td and adding it to the current vehicle speed Vn. In each equation in this embodiment, the velocity unit is m / s, the acceleration unit is m / s ² , the distance unit is m, and the time unit is s. Vs = Vn + Gdn × Td (1)
Here, the response delay time is from detection of a deceleration request, such as a communication delay between the ECUs 11 to 13, a calculation delay in each of the ECUs 11 to 13, a response delay of the brake actuator 32, a vehicle deceleration detection delay, etc. Including all delays. In addition, since the braking effectiveness varies depending on the temperature, the response delay can be made variable according to the situation, such as setting a response delay time corresponding to the brake.

  Further, as shown in the following equation (2), the inter-vehicle distance Ds at the start of deceleration is obtained by subtracting the current vehicle speed Vn multiplied by the response delay time Td from the current inter-vehicle distance Dn, It can be obtained by multiplying the acceleration / deceleration Gdn by the square of the response delay time Td and further subtracting the result obtained by multiplying by 1/2.

Ds = Dn−Vn × Td−1 / 2 × Gdn × Td ² (2)
Further, as shown in the equation (3), the acceleration / deceleration Gds for stop control is obtained by adding a negative sign to the square of the vehicle speed Vs of the own vehicle at the start of deceleration from the inter-vehicle distance Ds at the start of deceleration. It can be obtained by subtracting the inter-vehicle distance Dt and dividing by the doubled value.

Gds = −Vs ² / {2 × (Ds−Dt)} (3)
However, the acceleration / deceleration Gds for stop control needs to be larger than the maximum value of the deceleration in the stop control and smaller than the deceleration just before the stop. The deceleration just before stopping needs to be slow enough not to lose the creep torque of the engine, but if it is too small, a shock will occur immediately before stopping, and if it becomes too large, it will progress if it becomes slippery without stopping It will be. Considering these points, the deceleration range just before stopping is set as appropriate.

  In this way, the initial control value of the control logic for stop control can be set.

  If it is determined in step S4 that the previous value of the calculation flag is not OFF, the required acceleration / deceleration calculation for stop control described later is performed (S8).

  Returning to step S2, when it is determined that the required acceleration when the follow-up running control is performed becomes positive, it is then judged whether the follow-up running control or the stop control is performed. Therefore, first, it is determined whether or not the requested accelerations in the past several times, for example, five times are all positive (S6). Here, when the required acceleration / deceleration for the follow-up running control is positive, there is a possibility that a large deceleration occurs on an uphill or the like even when the stop control is performed. In such a case, even if the stop control is being performed, the transition from the stop control to the follow-up running control is temporarily performed, and the inter-vehicle distance is reduced by the requested acceleration for the follow-up running control without performing the required acceleration / deceleration calculation for the stop control. Is preferred. However, if it is determined that the shift to the follow-up traveling control is performed with a single positive / negative determination, there is a high possibility of frequently performing an operation of turning on / off the required acceleration / deceleration calculation flag for stop control due to the influence of noise. In order to prevent such a situation, when canceling the requested acceleration / deceleration calculation for stop control, it is determined whether or not the requested acceleration is all positive by looking at the history of the past several times, for example, about 5 times. (S6).

  As a result, if it is determined that all the required accelerations are positive, it can be determined that the required acceleration for the follow-up running control is obtained. Therefore, the required acceleration for the follow-up running control is calculated, and the engine ECU 12 and the brake ECU 13 Output (S10).

  On the other hand, if it is determined that the acceleration / deceleration in the past several times is negative even once, whether or not the stop control calculation flag is ON in order to determine whether or not the stop control is currently being performed. Is determined (S7). As a result, if it is determined that the calculation flag is not ON, it can be determined that the following traveling control is being performed instead of the stop control. Therefore, the required acceleration / deceleration for the following traveling control is calculated without performing the stop control, and the engine ECU 12 And it outputs to brake ECU13 (S10).

  If it is determined in step S7 that the calculation flag is ON, the required acceleration / deceleration for stop control is calculated by calculation (S8). When it is determined in step S4 that the previous value of the calculation flag is not OFF, and when it is determined in step S7 that the calculation flag is ON, the initial value is always set in step S5. When calculating the required acceleration / deceleration for stop control in step S8, the required acceleration / deceleration to be actually output of time or vehicle speed is interpolated based on the acceleration / deceleration set in step S5.

  As shown in FIG. 5, in step S5, the vehicle speed Vs of the host vehicle at the time T0 when the acceleration / deceleration calculation for stop control is started and the difference between the inter-vehicle distance Ds and the inter-vehicle distance Dt at the time of stop (3 ), The acceleration / deceleration for stop control (hereinafter referred to as “requested acceleration / deceleration initial value”) Gds as an initial value is calculated. The requested acceleration / deceleration initial value Gds is often different from the requested acceleration / deceleration (current requested acceleration / deceleration, hereinafter referred to as “requested acceleration / deceleration current value”) Gdn at time T0 when the acceleration / deceleration calculation for stop control is started. Here, if the acceleration / deceleration Gds for stop control obtained by the above equation (3) is used as the required acceleration / deceleration as it is, if the required acceleration / deceleration initial value Gds and the requested acceleration / deceleration current value Gdn are different, the acceleration / deceleration for stop control is As the calculation starts, the required acceleration / deceleration changes nonlinearly. This non-linear change in acceleration / deceleration causes a reduction in ride comfort for the occupant.

  In order to deal with such a problem, in step S8, in order to interpolate the required acceleration / deceleration, the acceleration / deceleration for stop control is set to the required acceleration / deceleration current value Gdn instead of the required acceleration / deceleration initial value Gds. Thus, the acceleration / deceleration at the end of the follow-up running control and the acceleration / deceleration at the start of the stop control are made linear. When the requested acceleration / deceleration by the stop control is continuously calculated, the requested acceleration / deceleration calculated immediately before is made linear with the requested acceleration / deceleration calculated this time. In this way, it is possible to prevent a decrease in riding comfort for the occupant.

  By the way, if the requested acceleration / deceleration for stop control is simply set to the requested acceleration / deceleration current value Gdn, the own vehicle cannot be stopped with the desired distance between the preceding vehicle and the preceding vehicle. . In order to interpolate this point, it is necessary to adjust the required acceleration / deceleration. Explaining this point, as shown in FIG. 5, when the requested acceleration / deceleration current value Gdn is smaller than the requested acceleration / deceleration initial value Gds, if the acceleration / deceleration is continued at the requested acceleration / deceleration current value Gdn, The distance becomes shorter and the vehicle is too far away from the preceding vehicle. Therefore, control is performed to increase the required acceleration / deceleration before the time Ts elapses, where Ts is the time when the host vehicle stops. Since the required acceleration / deceleration is increased, the distance for stopping the own vehicle can be increased. Therefore, the own vehicle can be stopped while maintaining a desired inter-vehicle distance with respect to the preceding vehicle.

  Further, when increasing the required acceleration / deceleration, the required deceleration immediately before the host vehicle stops is reduced (the required acceleration / deceleration is increased). Immediately before the host vehicle stops, the required acceleration / deceleration is always a deceleration, and by reducing this required deceleration, the same state as the “removal” performed by the driver can be created. Since it is possible to perform the control to create the same state as such “extraction”, the driver when stopping the vehicle can be stopped with a normal feeling, and a sense of incongruity can be prevented.

  In this way, control is performed to create the same state as “unplugged”, but the timing for starting control to create the same state as “unplugged” (timing to start reducing deceleration) is related to the required acceleration / deceleration initial value Gds. Thus, for example, it can be obtained in advance in step S5. The timing for starting the control to create the same state as this “extraction” can be obtained by integrating the deceleration to be output and calculating backward from the estimated value of the distance change, but this procedure takes time. Become.

  Therefore, as a simple method, from the start of stop control to the stop of the host vehicle, the travel distance when moving at the required acceleration / deceleration initial value and the requested deceleration current value, and then the acceleration / deceleration is set. Reduce the distance so that the distance traveled when the vehicle is moved is the same. Then, the reduction start vehicle speed when starting to reduce the acceleration / deceleration is obtained, and the acceleration / deceleration may be started to decrease when the vehicle speed of the host vehicle becomes the reduction start vehicle speed.

In the graph showing the time change of acceleration / deceleration, the area of the portion surrounded by the acceleration / deceleration is a value related to the movement distance. The area of the portion indicating the distance when moving with the required acceleration / deceleration initial value Gds and the portion indicating the distance when moving with the required acceleration / deceleration current value Gdn and then reducing the required deceleration immediately before stopping. The area may be the same .

  Specifically, the areas of both can be made equal as follows. As shown in FIG. 6, the vehicle speed Vs when the stop control is started and the reduction start vehicle speed Vc when the deceleration starts to be reduced. Further, the acceleration when the vehicle stops is assumed to be Gs. The vehicle speed when the vehicle stops is zero. At this time, the area S1 related to the moving distance when moving at the required acceleration / deceleration initial value Gds is expressed by the following equation (4), and moves at the required acceleration / deceleration current value Gdn, and then the required deceleration is reduced immediately before stopping. The area S2 related to the moving distance when expressed is expressed by the following equation (5).

S1 = Gds × Vs (4)
S2 = Gdn × (Vs−Vc) + [(Gdn + Gs) × Vc] / 2 (5)
Here, the reduction start vehicle speed Vc can be expressed by the following equation (6).

Vc = 2 × (Gds−Gdn) · Vs / (Gs−Gdn) (6)
In this way, the reduction start vehicle speed Vc can be obtained. When the stop control is started, the host vehicle speed Vm is monitored, and Gdn is continuously output until the host vehicle speed Vm drops below the reduction start vehicle speed Vc. When the host vehicle speed Vm cuts the reduction start vehicle speed Vc, the following (7 ) Calculate the output from the equation.

((Vm) × Gdn + (Vc−Vm) × Gs) / Vc (7)
In this way, it is possible to easily calculate the timing at which the control to create the same state as “unplug” is started after the deceleration is started to be reduced. When the required acceleration / deceleration for stop control is calculated, the required acceleration / deceleration for stop control is output to the engine ECU 12 and the brake ECU 13 (S9). When the requested acceleration / deceleration for stop control is output, it is determined whether or not the control is to be ended (S11). If the control is to be ended, the control is ended. If not, the process returns to step S2 and the same processing is repeated. Similarly, if the required acceleration / deceleration for follow-up running control is output in step S10, it is determined whether or not the control is to be ended (S11). Go back to and repeat the same process.

  As described above, in the travel control device 1 according to the present embodiment, the change in the acceleration / deceleration of the stop control is linearly changed from the acceleration / deceleration of the follow-up travel control by setting the required acceleration / deceleration Gdn. For this reason, it is possible to prevent a decrease in the riding comfort for the occupant when shifting from the follow-up running control to the stop control. Moreover, in the traveling control apparatus 1, the same state as the “removal” performed by the driver is created by reducing the required deceleration immediately before the host vehicle stops. For this reason, the driver at the time of stopping the own vehicle can be stopped in a normal sense, and a sense of incongruity can be prevented.

It is a block block diagram of the traveling control apparatus which concerns on embodiment of this invention. It is a schematic diagram which shows the position and speed relationship between the own vehicle and a preceding vehicle. It is a flowchart which shows the procedure of the traveling control by a traveling control apparatus. (A) is a schematic diagram showing the positional relationship between the own vehicle and the preceding vehicle when the stop control is to be started, and (b) is a schematic diagram showing the positional relationship between the own vehicle and the preceding vehicle after a response delay has occurred. FIG. It is a graph which shows the relationship between the stop time of a vehicle at the time of performing stop control, and speed (acceleration). It is a figure for demonstrating the method of calculating the reduction start vehicle speed easily.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Travel control apparatus, 11 ... Vehicle distance control ECU, 12 ... Engine ECU, 13 ... Brake ECU, 21 ... Radar sensor, 22 ... Wheel speed sensor, 23 ... G sensor, 31 ... Electronic throttle, 32 ... Brake actuator, MM ... Own car, MP ... preceding vehicle.

Claims (4)

Follow-up running control is performed to control the acceleration / deceleration of the host vehicle so as to maintain an inter-vehicle distance with respect to a preceding vehicle traveling in the same lane as the host vehicle, and when the preceding vehicle stops, the host vehicle is subjected to predetermined acceleration / deceleration. In the travel control device that starts the deceleration by the initial speed value and performs stop control to stop the host vehicle at a position where the distance from the preceding vehicle is constant,
When shifting from the follow-up running control to the stop control, when the requested acceleration / deceleration current value that is the requested acceleration / deceleration at the time of the transition is smaller than the acceleration / deceleration initial value ,
Continue the acceleration / deceleration calculated in the follow-up running control until a predetermined timing,
After the predetermined timing, a travel control device that performs control to reduce the magnitude of acceleration / deceleration of the host vehicle. The predetermined timing is
After controlling the acceleration / deceleration of the own vehicle so as to maintain the inter-vehicle distance with respect to the preceding vehicle, the acceleration / deceleration of the own vehicle is set to stop the own vehicle at a position where the distance from the preceding vehicle is constant. The mileage of the vehicle when controlled,
The travel distance of the host vehicle when the acceleration / deceleration of the host vehicle is controlled to stop the host vehicle at a position where the distance from the preceding vehicle is constant after the transition to the stop control,
The travel control device according to claim 1, wherein the timings coincide with each other.   The travel control device according to claim 2, wherein the predetermined timing is determined based on a vehicle speed of the host vehicle. The travel control device according to claim 3, wherein the predetermined timing is when the vehicle speed of the host vehicle reaches a vehicle speed Vc obtained by the following equation (6).
Vc = 2 × (Gds−Gdn) · Vs / (Gs−Gdn) (6)
However, Gds: acceleration / deceleration when controlling the host vehicle so that the host vehicle is stopped at a position where the distance from the preceding vehicle is constant
Gdn: Acceleration / deceleration when controlling the host vehicle so as to maintain the inter-vehicle distance with respect to the preceding vehicle
Vs: Vehicle speed when stop control is started
Gs: acceleration when the vehicle stops

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