JP3724296B2 - Vehicle travel control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicular travel control device, and in particular, an inter-vehicle distance that stops the travel of the host vehicle so that the inter-vehicle distance between the host vehicle and the preceding vehicle is maintained at a predetermined value when the travel of the preceding vehicle stops. The present invention relates to a vehicular travel control apparatus suitable for executing control.
[0002]
[Prior art]
Conventionally, as disclosed in, for example, Japanese Patent Laid-Open No. 10-338054, in order to cause the host vehicle to travel following the preceding vehicle, the actual vehicle distance between the host vehicle and the preceding vehicle is maintained at the target inter-vehicle distance. A travel control device that controls engine output and braking force is known. In such a travel control device, when the preceding vehicle stops due to traffic congestion or the like, inter-vehicle distance control is executed to stop the own vehicle so that the inter-vehicle distance between the own vehicle and the preceding vehicle becomes a predetermined value. Therefore, according to the conventional travel control device, the driver can stop the host vehicle so that the inter-vehicle distance from the preceding vehicle is maintained at a predetermined value without the driver performing an accelerator operation or a brake operation.
[0003]
[Problems to be solved by the invention]
In a situation where the host vehicle is stopped by the inter-vehicle distance control, the driver may desire to reduce the inter-vehicle distance between the host vehicle and the preceding vehicle. However, in the above-described conventional device, even if the accelerator pedal is depressed while the host vehicle is stopped by the inter-vehicle distance control, the host vehicle is not accelerated and the stopped state of the host vehicle is maintained. Therefore, in the above-described conventional apparatus, it is impossible to reduce the inter-vehicle distance between the host vehicle and the preceding vehicle in a situation where the host vehicle is stopped by the inter-vehicle distance control.
[0004]
As a method of reducing the inter-vehicle distance between the host vehicle and the preceding vehicle in a situation where the host vehicle is stopped by the inter-vehicle distance control, it is conceivable to stop the inter-vehicle distance control while the accelerator pedal is depressed. According to this method, when the accelerator pedal is depressed, the inter-vehicle distance control is stopped and the host vehicle is accelerated, whereby the inter-vehicle distance can be reduced.
[0005]
In the above method, when the depression of the accelerator pedal is released, the suspension of the inter-vehicle distance control is released. That is, the inter-vehicle distance control is resumed. When the inter-vehicle distance control is resumed in a situation where the inter-vehicle distance between the host vehicle and the preceding vehicle is smaller than the predetermined value by the inter-vehicle distance control, the inter-vehicle distance is promptly moved toward the predetermined value by the inter-vehicle distance control. There is a risk that the host vehicle is suddenly braked so as to increase. Therefore, when the inter-vehicle distance control is resumed under a situation where the inter-vehicle distance is small, the ride comfort of the occupant may be deteriorated.
[0006]
In order to prevent the ride comfort of the occupant from deteriorating when the vehicle is stopped, it is desirable to suppress the deceleration to a small value immediately before the vehicle is stopped. However, immediately before the host vehicle is stopped by the inter-vehicle distance control, the difference between the vehicle speed detected by the output signal of the vehicle speed sensor and the actual vehicle speed may become large, and the deceleration with respect to the actual vehicle speed is smaller than the desired value. May be larger. In this case, the host vehicle is suddenly braked, so that the ride comfort of the occupant may be deteriorated when the host vehicle is stopped by the inter-vehicle distance control.
[0007]
The present invention has been made in view of the above points, and is a vehicle travel control capable of preventing the ride comfort of an occupant from deteriorating when inter-vehicle distance control is executed with a preceding vehicle. An object is to provide an apparatus.
[0008]
[Means for Solving the Problems]
  According to the first aspect of the present invention, as described in claim 1, when the traveling of the preceding vehicle stops, the inter-vehicle distance that stops the traveling of the own vehicle so that the inter-vehicle distance between the preceding vehicle and the own vehicle is maintained at a predetermined value. In a vehicular travel control apparatus capable of executing control,
  An inter-vehicle distance control stop means for pausing or canceling the inter-vehicle distance control when an accelerator pedal is depressed after traveling of the host vehicle is stopped by the inter-vehicle distance control;
  An inter-vehicle distance control stop canceling means for canceling the pause or stop of the inter-vehicle distance control by the inter-vehicle distance control stop means when the depression of the accelerator pedal is released;
  When suspension or cancellation of the inter-vehicle distance control is canceled by the inter-vehicle distance control stop canceling means,Deceleration setting means for setting the deceleration to a value smaller than the maximum deceleration allowed in the vehicleWhen,
  It is achieved by a vehicular travel control device comprising:
[0009]
In the present invention, when the accelerator pedal is depressed after the traveling of the host vehicle is stopped by the inter-vehicle distance control, the inter-vehicle distance control is stopped or stopped, so that the inter-vehicle distance between the own vehicle and the preceding vehicle becomes the inter-vehicle distance control. As a result, the distance becomes smaller than the inter-vehicle distance when traveling of the host vehicle is stopped. When depression of the accelerator pedal is released in such a state, suspension or cancellation of the inter-vehicle distance control is released. When the suspension or cancellation of the inter-vehicle distance control is canceled in a situation where the inter-vehicle distance is small, the host vehicle is suddenly braked at the maximum deceleration so that the inter-vehicle distance increases toward a predetermined value by the inter-vehicle distance control. There is a risk.
[0010]
  In the present invention, when suspension or cancellation of the inter-vehicle distance control is canceled,Deceleration is set to a value smaller than the maximum speed allowed in the vehicleIs done. For this reason, even when the suspension or cancellation of the inter-vehicle distance control is canceled in a situation where the inter-vehicle distance is small, the host vehicle is prevented from being decelerated at the maximum deceleration. Therefore, according to the present invention, it is possible to prevent the ride comfort of the occupant from deteriorating when the inter-vehicle distance control is executed with the preceding vehicle.
[0011]
In this case, as described in claim 2, in the vehicle travel control device according to claim 1,
The inter-vehicle distance control stop canceling unit may cancel pausing or canceling the inter-vehicle distance control when a brake operation is performed after the accelerator pedal is released.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a system configuration diagram of a vehicle travel control apparatus according to a first embodiment of the present invention. The system of this embodiment includes a radar electronic control unit (hereinafter referred to as a radar ECU) 10 and a brake control electronic control unit (hereinafter referred to as a brake ECU) 12. Be controlled.
[0016]
For example, a laser radar sensor 14 disposed near the front grill of the vehicle is connected to the radar ECU 10. The laser radar sensor 14 includes a light emitting unit that emits laser light having a millimeter wave as a carrier wave toward a predetermined area in front of the vehicle, and a light receiving unit that receives reflected light of the radar light irradiated forward. . The laser radar sensor 14 is configured to two-dimensionally scan the front of the vehicle at a predetermined cycle. The laser radar sensor 14 radars a signal corresponding to the time until the reflected light of the laser light is received by the light receiving unit after the laser light is irradiated from the light emitting unit, and a signal corresponding to the incident angle of the reflected light. Output to the ECU 10. Based on the output signal of the laser radar sensor 14, the radar ECU 10 determines whether there is a preceding vehicle existing in a predetermined area ahead of the host vehicle, the inter-vehicle distance d between the host vehicle and the preceding vehicle, and the relative speed of the preceding vehicle with respect to the host vehicle. R_XYIs detected.
[0017]
A brake ECU 12 is connected to the radar ECU 10. The radar ECU 10 supplies the detection result of the laser radar sensor 14 to the brake ECU 12. A vehicle speed sensor 16 is connected to the brake ECU 12. The vehicle speed sensor 16 outputs a pulse signal at a cycle corresponding to the speed of the host vehicle. The brake ECU 12 determines the vehicle speed V of the host vehicle based on the output signal of the vehicle speed sensor 16._XVehicle speed V_XAnd relative speed R_XYVehicle speed V of the preceding vehicle based on_YIs detected.
[0018]
The brake ECU 12 is also connected to a travel mode selection switch 18 disposed in the passenger compartment so that the driver can operate, and a brake actuator 20 for braking the vehicle. The travel mode selection switch 18 is a switch for allowing the driver to travel at a reduced speed while following the preceding vehicle without performing a brake operation. The brake actuator 20 is driven according to a logic predetermined by the brake ECU 12 when braking the vehicle.
[0019]
When the travel mode selection switch 18 is in the off state, the brake ECU 12 drives the brake actuator 20 so that the host vehicle decelerates according to the driver's brake operation. On the other hand, when the travel mode selection switch 18 is in the ON state, the preceding vehicle has stopped, particularly due to traffic congestion, so that the host vehicle decelerates while following the preceding vehicle regardless of the driver's braking operation. In this case, the brake actuator 20 is driven so that the own vehicle stops while maintaining the inter-vehicle distance from the preceding vehicle at a constant value.
[0020]
The brake ECU 12 is also connected with an alarm device 22 for alerting the driver. The alarm device 22 detects the following distance when the preceding vehicle starts forward after the host vehicle is stopped so that the distance between the preceding vehicle and the preceding vehicle becomes a constant value under the condition that the travel mode selection switch 18 is in the ON state. When the vehicle becomes large, the vehicle is driven to prompt the driver to start the vehicle.
[0021]
An accelerator pedal switch 24 and a brake pedal switch 26 are further connected to the brake ECU 12. The accelerator pedal switch 24 is disposed in the vicinity of the accelerator pedal that the driver operates to accelerate the vehicle. The accelerator pedal switch 24 maintains an off state when the accelerator pedal is released, and outputs an on signal when the accelerator pedal is depressed. The brake pedal switch 26 is disposed in the vicinity of the brake pedal that the driver operates to brake the vehicle. The brake pedal switch 26 maintains an off state when the depression of the brake pedal is released, and outputs an on signal when the brake pedal is depressed.
[0022]
An accelerator position sensor 28 is disposed on the accelerator pedal. The accelerator position sensor 28 outputs a signal corresponding to the opening of the accelerator pedal. The output signal of the accelerator position sensor 28 is supplied to the brake ECU 12. The brake ECU 12 detects the opening degree θ of the accelerator pedal (hereinafter referred to as the accelerator opening degree θ) based on the output signal of the accelerator position sensor 28.
[0023]
Next, the operation of the system of this embodiment will be described.
In the system of the present embodiment, when the travel mode selection switch 18 is maintained in the off state, the brake ECU 12 decelerates the host vehicle according to the driver's brake operation. When the depression of the accelerator pedal is released under the condition that the travel mode selection switch 18 is switched from the off state to the on state, the brake ECU 12 has a preceding vehicle in the predetermined area in front of the host vehicle and the preceding vehicle. When the vehicle decelerates, the inter-vehicle distance between the preceding vehicle and the host vehicle is the vehicle speed V of the preceding vehicle._YThe host vehicle is decelerated while following the preceding vehicle so that the distance according to When the preceding vehicle stops, the host vehicle is stopped so that the distance between the preceding vehicle and the preceding vehicle becomes a constant value. Hereinafter, the control for stopping the host vehicle so that the inter-vehicle distance from the preceding vehicle becomes a constant value without the driver operating the brake pedal is referred to as inter-vehicle distance control.
[0024]
When the preceding vehicle starts while the host vehicle is stopped by the inter-vehicle distance control so that the inter-vehicle distance from the preceding vehicle is maintained at a constant value, the brake ECU 12 The alarm device 22 is driven so that an alarm for prompting the vehicle to start is issued. Thereafter, the host vehicle can start by the driver's accelerator operation.
[0025]
Thus, according to the above configuration, when the travel mode selection switch 18 is on and the accelerator pedal is released, the driver is not operated by the driver without operating the brake pedal. The vehicle can be decelerated by following the preceding vehicle, and can be stopped so that the distance between the preceding vehicle and the preceding vehicle becomes a constant value when the preceding vehicle stops.
[0026]
In the process in which the host vehicle is stopped so that the inter-vehicle distance between the host vehicle and the preceding vehicle becomes a constant value by the inter-vehicle distance control, the host vehicle is decelerated according to the target deceleration G expressed by the following equation (1). .
G = a [V_X/ V_Y・ {(T ・ V_X+ L) / d}^P-1] (1)
Here, a is the acceleration due to creep of the host vehicle (hereinafter referred to as creep acceleration), T is the vehicle head time, L is the target inter-vehicle distance, and P is a constant value larger than “1”. In the following description, the target deceleration G expressed by the above equation (1) is expressed as G₁And
[0027]
Therefore, according to this embodiment, the deceleration of the host vehicle is {(T · V_X+ L) / d} is smaller than 1, that is, the larger the inter-vehicle distance between the current vehicle and the preceding vehicle is larger than the target inter-vehicle distance, the smaller the vehicle speed V of the own vehicle._XIs the vehicle speed V of the preceding vehicle_YThe larger the value is, the larger the vehicle becomes, and the value becomes “0” when the host vehicle and the preceding vehicle travel at substantially the same speed while maintaining the target inter-vehicle distance.
[0028]
By the way, in the process where the host vehicle is stopped regardless of the driver's brake operation by the inter-vehicle distance control, the target deceleration G₁Will be decelerated according to. This target deceleration G₁Is the vehicle speed V_XSpecifically, it varies according to the output signal of the vehicle speed sensor 16. Vehicle speed V detected by the output signal of the vehicle speed sensor 16_X(Hereafter, estimated vehicle speed V_XCompared to the vehicle speed actually generated in the vehicle (hereinafter referred to as the actual vehicle speed) due to the detection principle or detection delay of the vehicle speed sensor 16 when the vehicle travels at an extremely low speed. It is a big value. That is, when the vehicle travels at an extremely low speed, the estimated vehicle speed V_XThe difference between the actual vehicle speed and the actual vehicle speed is increasing. For this reason, immediately before the own vehicle is stopped by the inter-vehicle distance control, there is a possibility that the own vehicle is suddenly braked because the target deceleration G becomes larger than a desired value.
[0029]
Therefore, in the present embodiment, the estimated vehicle speed V of the host vehicle immediately before the host vehicle is stopped by the inter-vehicle distance control._XIs reduced to a predetermined value, the calculation method of the target deceleration G is changed so that the target deceleration G of the host vehicle becomes a desired value without following the equation (1). The system of the present embodiment is based on the estimated vehicle speed V of the host vehicle through inter-vehicle distance control._XThe first feature is that sudden braking of the host vehicle is avoided by changing the calculation method of the target deceleration G when the vehicle speed decreases to a predetermined value.
[0030]
FIG. 2 shows that the distance between the host vehicle 30 and the preceding vehicle 32 is set to a predetermined value L by controlling the distance between vehicles.₁In the situation where the vehicle is stopped while maintaining the distance between the vehicles is the predetermined value L₁A predetermined value L smaller than₂The figure which represented typically the condition where the own vehicle 30 was moved so that it may become. In FIG. 2, the host vehicle 30 stopped by the inter-vehicle distance control is indicated by a solid line, and the inter-vehicle distance is set to a predetermined value L.₁The own vehicle 30 when it is made smaller than this is indicated by broken lines.
[0031]
In the present embodiment, when the own vehicle 30 is stopped by the inter-vehicle distance control, the inter-vehicle distance between the own vehicle 30 and the preceding vehicle 32 is a constant value L as shown by the solid line in FIG.₁Maintained. By the way, the own vehicle 30 sets the inter-vehicle distance to a constant value L by inter-vehicle distance control.₁In a situation where the vehicle is stopped while being maintained, the driver may desire to stop the host vehicle 30 by reducing the inter-vehicle distance. Therefore, in this embodiment, when the accelerator pedal is depressed in a situation where the host vehicle 30 is stopped by the inter-vehicle distance control, the inter-vehicle distance control is stopped. In this case, traveling of the host vehicle 30 is permitted and the host vehicle 30 is accelerated, so that the inter-vehicle distance from the preceding vehicle 32 can be reduced.
[0032]
In the present embodiment, the distance between the host vehicle 30 and the preceding vehicle 32 is a constant value L as described above.₁If the depression of the accelerator pedal is released under a situation where the distance is smaller than that, the suspension of the inter-vehicle distance control is released. That is, the host vehicle 30 is decelerated by the inter-vehicle distance control. However, at this time, it is assumed that the host vehicle is the target deceleration G of the above equation (1).₁To decelerate according to {(T · V_XWhen the term + L) / d} is larger than 1, the deceleration of the host vehicle 30 becomes excessive, and the host vehicle 30 may be decelerated rapidly.
[0033]
Therefore, in this embodiment, the inter-vehicle distance is a predetermined value L by inter-vehicle distance control.₁When the suspension of the inter-vehicle distance control is released under a situation where the vehicle speed is smaller than the maximum deceleration allowed in the vehicle without causing the deceleration of the host vehicle 30 to follow the above equation (1). It is supposed to be a smaller value. The system of the present embodiment has a second feature in that when the suspension of the inter-vehicle distance control is canceled, the braking of the host vehicle 30 is avoided by reducing the deceleration of the host vehicle 30 to a small value. ing.
[0034]
The contents of the processing for realizing the above-described characteristic function will be described below with reference to FIGS.
FIG. 3 shows a flowchart of an example of a control routine executed by the brake ECU 12 in the present embodiment in order to realize the first characteristic function. The routine shown in FIG. 3 is a scheduled interruption routine that is repeatedly activated every predetermined time. When the routine shown in FIG. 3 is started, first, the process of step 100 is executed.
[0035]
In step 100, it is determined whether or not the host vehicle is decelerating by inter-vehicle distance control. The process of step 100 is repeatedly executed until the above condition is satisfied. As a result, if it is determined that the above condition is satisfied, the process of step 102 is executed next.
In step 102, the estimated vehicle speed V of the host vehicle detected based on the output signal of the vehicle speed sensor 16._XIs the predetermined value V₀It is determined whether or not: The predetermined value V₀Is the estimated vehicle speed V based on the output signal of the vehicle speed sensor 16_XIs estimated to deviate from actual vehicle speed V_XFor example, a very small value of about 5 km / h. V_X≦ V₀Is not established, it can be determined that the host vehicle is traveling at a somewhat high vehicle speed, and the host vehicle is subject to the target deceleration G in the above equation (1).₁It is appropriate to decelerate according to. Therefore, V_X≦ V₀If it is determined that is not established, the process of step 104 is performed next.
[0036]
In step 104, a process of calculating the target deceleration G of the host vehicle according to the above equation (1) is executed.
On the other hand, in step 102 above, V_X≦ V₀If it is determined that is established, the process of step 106 is performed next.
In step 106, it is determined whether or not the current inter-vehicle distance d is less than or equal to the target inter-vehicle distance L, that is, whether or not the host vehicle is approaching the target inter-vehicle distance L or less with respect to the preceding vehicle. As a result, if it is determined that d ≦ L does not hold, the process of step 108 is executed next.
[0037]
In step 108, the target acceleration G of the host vehicle is a predetermined threshold value G._CLIt is determined whether or not: The predetermined threshold G_CLIs set to a small value compared to the deceleration at which the vehicle can stop against the creep force. As a result, G ≦ G_CLIf is not established, the process of step 110 is executed next.
In step 110, processing is performed to set the target deceleration G of the host vehicle to a value obtained by reducing the target deceleration G calculated in the previous routine by a predetermined gradient b (G = G−bt). The predetermined gradient b is set to a value of about 0.1 G / sec, for example.
[0038]
In step 108, the target deceleration G of the host vehicle is a predetermined threshold value G._CLIf it is determined that the following has occurred, the process of step 112 is then executed.
In step 112, the target deceleration G of the host vehicle is set to a predetermined threshold G._CLAfter a predetermined time T₁It is determined whether or not elapses. The processing of this step 112 is T₁It is repeatedly executed until elapses. As a result, T₁If it is determined that elapses, the process of step 106 is performed again.
[0039]
If it is determined in step 106 that d ≦ L is satisfied, that is, if the host vehicle has approached the preceding vehicle to the target inter-vehicle distance, the process of step 114 is executed next.
In step 114, the target deceleration G of the host vehicle is set to the predetermined threshold value G._CLGreater value G than_cmThe process to make is executed. The predetermined value G_cmIs set to a value slightly larger than the deceleration that can resist the creep force of the vehicle.
[0040]
When the target deceleration G of the host vehicle is calculated in step 104, 110, or 114, the process of step 116 is performed next.
In step 116, a process of supplying a command signal to the brake actuator 20 is executed so that the host vehicle is decelerated according to the target deceleration G calculated in the above steps. When the processing of step 116 is finished, the current routine is finished.
[0041]
According to the above processing, as shown in FIG.₀Until (time t₁Before) can be decelerated according to the target deceleration calculated by the above equation (1), and the estimated vehicle speed of the host vehicle is constant V₀(Time t₁And thereafter) can be decelerated according to a target deceleration that decreases with a predetermined gradient.
[0042]
Therefore, according to the present embodiment, the estimated vehicle speed V of the host vehicle_XIs a very small constant value V₀The estimated vehicle speed V_XThe target deceleration can be avoided from becoming larger than the desired value due to the difference between the actual vehicle speed and the actual vehicle speed, and the target deceleration is controlled to such an extent that the host vehicle can stop smoothly. be able to. Therefore, according to the present embodiment, the estimated vehicle speed V of the host vehicle_XIs a very small constant value V₀Since the sudden braking of the host vehicle is avoided after reaching the above, the ride comfort of the occupant can be prevented from deteriorating.
[0043]
FIG. 5 shows a flowchart of an example of a control routine executed by the brake ECU 12 in the present embodiment in order to realize the second characteristic function. The routine shown in FIG. 5 is a scheduled interrupt routine that is repeatedly activated every predetermined time. When the routine shown in FIG. 5 is started, first, the process of step 120 is executed.
In step 120, it is determined whether or not the host vehicle is decelerating by inter-vehicle distance control. The process of step 120 is repeatedly executed until the above condition is satisfied. As a result, when it is determined that the host vehicle is decelerating by inter-vehicle distance control, the process of step 122 is executed next.
[0044]
In step 122, the estimated vehicle speed V of the host vehicle_XIs determined to be “0”. As a result, V_XWhen it is determined that = 0 is not satisfied, the process of step 120 is repeatedly executed. On the other hand, V_XIf it is determined that = 0 holds, the process of step 124 is performed next.
In step 124, it is determined whether or not the accelerator pedal switch 24 is in an on state. The process of step 124 is repeatedly executed until the accelerator pedal switch 24 is turned on. As a result, if it is determined that the accelerator pedal switch 24 is in the ON state, the process of step 126 is performed next.
[0045]
In step 126, a process of setting the target deceleration G of the host vehicle to a value corresponding to the pedal stroke of the brake pedal is executed. When the accelerator pedal is depressed, the depression of the brake pedal is normally released. For this reason, when the processing of this step 126 is executed, the target deceleration G is normally substantially “0”. Therefore, when the processing of step 126 is executed, the braking force by the brake actuator 20 is released and the driving force corresponding to the amount of depression of the accelerator pedal is applied to the host vehicle. In this case, the inter-vehicle distance between the host vehicle and the preceding vehicle is smaller than the target inter-vehicle distance L.
[0046]
In step 128, it is determined whether or not the accelerator pedal switch 24 has been switched from the on state to the off state. The process of step 128 is repeatedly executed until the accelerator pedal switch 24 is switched to the off state. As a result, if it is determined that the accelerator pedal switch 24 is switched to the OFF state, the process of step 130 is performed next.
[0047]
In step 130, the target deceleration G of the host vehicle is set to a deceleration G that allows the vehicle to stop against the creep force._CLA process for obtaining a value obtained by adding a predetermined value α to the is executed. The predetermined value α is the deceleration G_CLIs set to about 10 to 20%. When the processing of step 130 is executed, the host vehicle decelerates at the calculated target deceleration G. When the processing of step 130 is finished, the current routine is finished.
[0048]
According to the above processing, when the accelerator pedal is depressed in a state where the host vehicle is stopped by the inter-vehicle distance control, the inter-vehicle distance control of the host vehicle with respect to the preceding vehicle can be released, and thereafter the accelerator pedal The inter-vehicle distance control can be resumed when the depression of is released. In the present embodiment, after the inter-vehicle distance control is resumed, the own vehicle has a deceleration G that can stop the vehicle against the creep force._CLIs decelerated at a target deceleration G that is slightly increased.
[0049]
As described above, according to this embodiment, when the inter-vehicle distance control is resumed under the situation where the inter-vehicle distance is small, the deceleration of the own vehicle does not follow the above equation (1), and the vehicle Can be set to a value smaller than the maximum deceleration allowed. For this reason, according to the present embodiment, when the inter-vehicle distance control is resumed under a situation where the inter-vehicle distance is small, the deceleration of the host vehicle follows the above equation (1) or is allowed in the vehicle. Therefore, the host vehicle can be prevented from decelerating suddenly due to the maximum deceleration. Therefore, according to the vehicle travel control apparatus of the present embodiment, while the inter-vehicle distance control is executed with the preceding vehicle, the ride comfort of the occupant is prevented from deteriorating, and the vehicle and the preceding vehicle are prevented from deteriorating. The inter-vehicle distance can be made smaller than the target inter-vehicle distance L.
[0050]
In the above embodiment, the brake ECU 12 executes the process of step 126 after the process of step 124 is executed, whereby the “inter-vehicle distance control stop means” described in the claims is By executing the process of step 130 after the process of step 128 is executed, the “inter-vehicle distance control stop canceling means” described in the claims is executed by executing the process of step 130. Each of the “maximum deceleration changing means” described in the above-mentioned range is realized.
[0051]
In the above embodiment, the brake ECU 12 detects the vehicle speed of the host vehicle based on the output signal of the vehicle speed sensor 16, whereby the “host vehicle speed detection means” described in the claims is the step 110. By executing the process, the “deceleration suppression means” described in the claims is realized.
By the way, in the above-described embodiment, the inter-vehicle distance control is stopped when the accelerator pedal is depressed while the host vehicle is stopped by the inter-vehicle distance control, and then the inter-vehicle distance is activated when the depression of the accelerator pedal is released. The suspension of the distance control is released, but the inter-vehicle distance control may be stopped when the accelerator pedal is depressed, and the inter-vehicle distance control may be resumed when the depression of the accelerator pedal is subsequently released.
[0052]
Further, in the above embodiment, when the depression of the accelerator pedal is released, the suspension of the inter-vehicle distance control is released, but after the depression of the accelerator pedal is released, the brake pedal is depressed, and When the depression is released, the suspension of the inter-vehicle distance control may be released. If the brake pedal is operated after the accelerator pedal is released, it can be determined that the driver is adjusting the stop position of the host vehicle relative to the preceding vehicle. In this case, there is no inconvenience even if the inter-vehicle distance control is executed between the host vehicle and the preceding vehicle.
[0053]
Furthermore, in the above embodiment, during the inter-vehicle distance control, the vehicle speed V of the host vehicle_XIs the predetermined threshold V₀The host vehicle is decelerated according to the target deceleration G calculated by the above equation (1) until the target deceleration G calculated by the above equation (1) is a predetermined value G.₀If the vehicle is smaller than the predetermined value G₀Decelerate with the predetermined value G₀When the value reaches the value, the vehicle may be decelerated according to the target deceleration G calculated by the above equation (1).
[0054]
FIG. 6 shows a case where the host vehicle is decelerated according to the target deceleration G calculated by the above equation (1), and the target deceleration G calculated by the above equation (1) is a predetermined value G.₀When the value is smaller than the predetermined value G₀At a predetermined value G₀The result of comparing the deceleration in the case where the vehicle is decelerated according to the target deceleration G calculated by the above equation (1) is shown. In FIG. 6, the case where the host vehicle is decelerated according to the target deceleration G calculated by the above equation (1) is indicated by a solid line, and the target deceleration G calculated by the above equation (1) and a predetermined value G.₀The case where the vehicle is decelerated based on the comparison result is shown by broken lines.
[0055]
According to the above modification, as shown by the broken line in FIG. 6, immediately after the inter-vehicle distance control is started, the own vehicle is decelerated at a certain large deceleration and immediately before the own vehicle is stopped by the inter-vehicle distance control. An increase in the deceleration of the host vehicle is avoided. For this reason, according to said structure, it can avoid that the deceleration timing of the own vehicle delays in inter-vehicle distance control, and it can prevent that a passenger | crew's riding comfort deteriorates just before the own vehicle stops. .
[0056]
Next, a second embodiment of the present invention will be described with reference to FIG.
In the first embodiment described above, when the inter-vehicle distance control is stopped by depressing the accelerator pedal in a situation where the own vehicle is stopped by the inter-vehicle distance control, the target deceleration G of the own vehicle is set to the predetermined value G._cmFrom 0 to “0”. However, the target deceleration G is a predetermined value G_cmIf the vehicle speed is quickly changed from “0” to “0”, the target deceleration G changes suddenly, causing the host vehicle to start suddenly. Therefore, in the first embodiment described above, the ride comfort of the occupant may deteriorate when the inter-vehicle distance control is suspended.
[0057]
Therefore, in this embodiment, when the inter-vehicle distance control is suspended, the target deceleration G of the host vehicle is set to a predetermined value G._cmFrom 0 to "0". The system of the present embodiment is realized when the brake ECU 12 executes the routine shown in FIG. 7 in the vehicle travel control apparatus shown in FIG.
FIG. 7 shows a flowchart of an example of a control routine executed by the brake ECU 12 in this embodiment. The routine shown in FIG. 7 is a scheduled interruption routine that is repeatedly activated every predetermined time. In FIG. 7, steps that execute the same processing as the steps shown in FIG. 5 are given the same reference numerals and description thereof is omitted. That is, in the routine shown in FIG. 7, after it is determined in step 124 that the accelerator pedal switch 24 is in the on state, the process of step 140 is executed.
[0058]
In step 140, it is determined whether or not the target acceleration G of the host vehicle is below “0”. As a result, if it is determined that G <0 is not satisfied, the process of step 142 is executed next. On the other hand, if it is determined that G <0 is established, the process of step 144 is performed next.
In step 142, a process of calculating the target deceleration G of the host vehicle according to the following equation (2) is executed.
[0059]
G = (θ₀-Θ) / θ₀・ G_cm                            ... (2)
However, θ₀Is the accelerator opening of the accelerator pedal maintained at a constant value, and is set to about 5 °, for example. G_cmIs a target deceleration when the host vehicle is stopped by inter-vehicle distance control.
According to such processing, the target deceleration G of the host vehicle decreases as the accelerator opening θ increases, and the accelerator opening θ becomes a constant value θ.₀When it reaches, it becomes “0”.
[0060]
In step 144, a process of setting the target deceleration G of the host vehicle to “0” is executed.
When the process of step 142 or 144 is completed, the process of step 146 is executed next.
In step 146, as in step 128, it is determined whether or not the accelerator pedal switch 24 has been switched from the on state to the off state. As a result, when it is determined that the above condition is not satisfied, the processing after step 140 is executed again. On the other hand, if it is determined that the above condition is satisfied, the process of step 130 is executed, and then the current routine is terminated.
[0061]
According to the above processing, when the inter-vehicle distance control is suspended, the target deceleration G of the host vehicle can be changed according to the accelerator opening θ of the accelerator pedal. Specifically, the target deceleration G can be reduced as the accelerator opening degree θ increases. For this reason, according to the present embodiment, the target deceleration G of the host vehicle is equal to the predetermined value G._cmIt is possible to avoid the immediate change from “0” to “0”. In this case, the own vehicle travels at a reduced speed in accordance with the driver's accelerator operation, so that the inter-vehicle distance control is suspended without causing the driver to feel uncomfortable. Therefore, according to the present embodiment, it is possible to prevent the ride comfort of the occupant from deteriorating when the inter-vehicle distance control is suspended.
[0062]
By the way, in the above embodiment, the target deceleration G is set to the predetermined value G when the inter-vehicle distance control is suspended._cmThe target deceleration G is changed from “0” to (G) when the suspension of the inter-vehicle distance control is canceled._CLIt is good also as making it change smoothly to + (alpha). In this case, when the suspension of the inter-vehicle distance control is canceled, the ride comfort of the occupant is prevented from deteriorating.
[0063]
Further, in the above embodiment, when the inter-vehicle distance control is suspended, the target deceleration G is reduced according to the accelerator opening θ of the accelerator pedal, but the target deceleration G is shown in FIG. As shown, the accelerator opening θ is a predetermined threshold value θ.₁If the vehicle speed exceeds V,_XAnd vehicle speed V of the preceding vehicle_Y, Relative speed R_XY, And a predetermined gradient A that may vary depending on the inter-vehicle distance d. In this case, when the accelerator pedal is depressed to some extent, the target deceleration G gradually decreases. For this reason, even in such a configuration, when the inter-vehicle distance control is suspended, the target deceleration G is equal to the predetermined value G._cmBy avoiding the immediate change from “0” to “0”, the ride comfort of the occupant is prevented from deteriorating.
[0064]
Further, when the suspension of the inter-vehicle distance control is canceled, the target deceleration G is set to the vehicle speed V of the host vehicle as shown in FIG._XAnd vehicle speed V of the preceding vehicle_Y, Relative speed R_XY, And a predetermined gradient C that may vary according to the inter-vehicle distance d. In this case, the target deceleration G gradually increases in the process of releasing the accelerator pedal. Even in such a configuration, when the suspension of the inter-vehicle distance control is canceled, the target deceleration G is prevented from being immediately changed from “0”, thereby preventing the ride comfort of the passenger from deteriorating. .
[0065]
【The invention's effect】
  As described above, according to the first and second aspects of the invention, sudden braking of the host vehicle is avoided even when the inter-vehicle distance control is executed in a situation where the inter-vehicle distance from the preceding vehicle is small. By this, it is possible to prevent deterioration of the ride comfort of the occupant.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram of a vehicle travel control apparatus according to a first embodiment of the present invention.
FIG. 2 shows a distance L between the host vehicle and a preceding vehicle by a predetermined value L.₁In the situation where the vehicle is stopped while maintaining the distance between the vehicles is the predetermined value L₁A predetermined value L smaller than₂It is the figure which represented typically the condition where the own vehicle was moved so that it might become.
FIG. 3 shows an estimated speed V of the host vehicle in the present embodiment._X3 is a flowchart of an example of a control routine that is executed to avoid sudden braking of the host vehicle due to an increase in the difference between the actual vehicle speed and the actual vehicle speed.
4 is a target deceleration G and a vehicle speed V of the host vehicle when the routine shown in FIG. 3 is executed._X4 is a time chart of an inter-vehicle distance d between the host vehicle and a preceding vehicle.
FIG. 5 is executed in the present embodiment to avoid sudden braking of the host vehicle due to cancellation of inter-vehicle distance control when the inter-vehicle distance between the host vehicle and the preceding vehicle is small. 6 is a flowchart of an example of a control routine.
FIG. 6 shows a case where the host vehicle is decelerated according to the target deceleration G calculated by the equation (1) and the target deceleration G calculated by the equation (1) is a predetermined value G in the present embodiment.₀When the value is smaller than the predetermined value G₀At a predetermined value G₀It is a figure which shows the result of having compared the deceleration in the case where it decelerates according to the target deceleration G calculated by (1) Formula when it reaches | attains.
FIG. 7 is a flowchart of an example of a control routine executed in the second embodiment of the present invention.
FIG. 8 is a time chart of an accelerator opening θ and a target deceleration G in a modified example of the present invention.
[Explanation of symbols]
12 Electronic control unit for brake control (brake ECU)
16 Vehicle speed sensor
18 Travel mode selection switch
20 Brake actuator
24 Accelerator pedal switch
26 Brake pedal switch

Claims (2)

In the vehicular travel control device capable of executing inter-vehicle distance control for stopping the travel of the host vehicle so that the inter-vehicle distance between the preceding vehicle and the host vehicle is maintained at a predetermined value when the travel of the preceding vehicle stops.
An inter-vehicle distance control stop means for pausing or canceling the inter-vehicle distance control when an accelerator pedal is depressed after traveling of the host vehicle is stopped by the inter-vehicle distance control;
An inter-vehicle distance control stop canceling means for canceling the pause or stop of the inter-vehicle distance control by the inter-vehicle distance control stop means when the depression of the accelerator pedal is released;
Deceleration setting means for setting the deceleration of the host vehicle to a value smaller than the maximum deceleration permitted in the vehicle when the suspension or cancellation of the inter-vehicle distance control is canceled by the inter-vehicle distance control stop canceling means; ,
A vehicle travel control apparatus comprising: The vehicle travel control apparatus according to claim 1,
The inter-vehicle distance control stop canceling means cancels pausing or stopping of the inter-vehicle distance control when a brake operation is performed after the accelerator pedal is released. .

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