Deceleration assistance device, deceleration assistance method, and deceleration assistance program

Abstract

The invention provides a deceleration assistance device, a deceleration assistance method, and a deceleration assistance program. The deceleration assist device executes deceleration control for decelerating the vehicle when the vehicle speed is greater than a target vehicle speed that is set as a target value for the vehicle speed when the vehicle travels on a curve. The deceleration assist device is configured so as not to execute the deceleration control by increasing the target vehicle speed by a predetermined value or even if the vehicle speed is greater than the target vehicle speed when a predetermined condition that a decrease in deceleration of the vehicle is detected while the vehicle is traveling on a curve is satisfied.

Description

Technical Field

[0001] The invention relates to a deceleration assisting device, a deceleration assisting method and a deceleration assisting program. Background Art

[0002] There is known a driving assistance device that automatically controls the acceleration and deceleration of a vehicle when the vehicle travels on a curve to achieve smooth travel of the vehicle on the curve (see, for example, Japanese Patent Application Laid-Open No. 2008-189199). Summary of the invention

[0003] When the vehicle operator releases the brake pedal while the vehicle is traveling on a curve and there is some deceleration left in the vehicle at that time, the vehicle operator may determine that the vehicle speed has been sufficiently reduced and therefore deceleration of the vehicle under deceleration control is not necessary. If deceleration control is executed at this time, the vehicle operator may feel uncomfortable.

[0004] An object of the present invention is to provide a deceleration assist device, a deceleration assist method, and a deceleration assist program that can suppress a situation in which a vehicle operator feels uncomfortable due to deceleration control being executed when the vehicle is traveling on a curve.

[0005] The deceleration assist device according to the present invention includes a control device, which performs deceleration control to decelerate the vehicle when the vehicle speed is greater than a target vehicle speed set as a target value of the vehicle speed when the vehicle is traveling on a curve. Furthermore, the control device is configured to increase the target vehicle speed by a predetermined value or not perform the deceleration control even if the vehicle speed is greater than the target vehicle speed when a predetermined condition is satisfied that a decrease in the deceleration of the vehicle is detected when the vehicle is traveling on the curve.

[0006] As described above, when the vehicle operator releases the brake pedal while the vehicle is traveling on a curve and there is some deceleration left in the vehicle at that time, the vehicle operator may determine that the vehicle speed has been sufficiently reduced and therefore deceleration of the vehicle under deceleration control is not necessary. If deceleration control is executed at this time, the vehicle operator may feel uncomfortable.

[0007] According to the deceleration assist device of the present invention, when a predetermined condition that a decrease in the deceleration of the vehicle is detected when the vehicle is traveling on a curve is satisfied and the operator of the vehicle determines that the vehicle speed has been sufficiently reduced and there is a high possibility that the deceleration of the vehicle under the deceleration control is not required, the target vehicle speed is increased by a predetermined value or the deceleration control is not performed even if the vehicle speed is greater than the target vehicle speed. Therefore, it is possible to suppress the situation where the operator of the vehicle feels uncomfortable due to the deceleration control being performed when the vehicle is traveling on a curve.

[0008] Furthermore, in the deceleration assist device according to the present invention, the predetermined condition may include a condition that the deceleration of the vehicle is equal to or greater than a predetermined deceleration at a time when a decrease in deceleration of the vehicle is detected.

[0009] According to this, the target vehicle speed is increased when the vehicle deceleration is large and the possibility of sufficient load being applied to the front wheels of the vehicle is high. Therefore, it is possible to more appropriately suppress the situation where the vehicle operator feels uncomfortable due to the deceleration control when the vehicle is traveling on a curve.

[0010] Furthermore, in the deceleration assist device according to the present invention, the predetermined condition may include a condition that a decrease in the deceleration of the vehicle is detected at a time point when the vehicle enters the curve.

[0011] According to this, when the deceleration of the vehicle starts to decrease or has decreased at the time when the vehicle enters the curve, the target vehicle speed is increased when there is a high possibility that the vehicle speed has been sufficiently reduced for the vehicle operator at the time when the vehicle enters the curve. Therefore, it is possible to more appropriately suppress the situation where the vehicle operator feels uncomfortable due to the deceleration control when the vehicle is traveling on the curve.

[0012] In addition, the deceleration assist method of the present invention is a method for executing a deceleration control to decelerate the vehicle when the vehicle speed is greater than a target vehicle speed set as a target value of the vehicle speed when the vehicle is traveling on a curve. Furthermore, the deceleration assist method of the present invention comprises the following steps: when a predetermined condition that a decrease in the deceleration of the vehicle is detected when the vehicle is traveling on the curve is satisfied, the target vehicle speed is increased by a predetermined value, or the deceleration control is not executed even if the vehicle speed is greater than the target vehicle speed.

[0013] According to this, for the same reasons as described above, it is possible to suppress a situation in which the operator of the vehicle feels uncomfortable due to the execution of the deceleration control when the vehicle is traveling on a curve.

[0014] In addition, the deceleration assisting program according to the present invention is a program for executing a deceleration control for decelerating the vehicle when the vehicle speed is greater than a target vehicle speed set as a target value of the vehicle speed when the vehicle is traveling on a curve. The deceleration assisting program according to the present invention is configured to increase the target vehicle speed by a predetermined value, or not execute the deceleration control even if the vehicle speed is greater than the target vehicle speed, when a predetermined condition that a decrease in the deceleration of the vehicle is detected when the vehicle is traveling on the curve is satisfied.

[0015] According to this, for the same reasons as described above, it is possible to suppress a situation in which the operator of the vehicle feels uncomfortable due to the execution of the deceleration control when the vehicle is traveling on a curve.

[0016] The components of the present invention are not limited to the embodiments of the present invention described below with reference to the drawings. Other objects, other features and additional advantages of the present invention should be easily understood from the description of the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0018] Figure 1 It is a diagram showing a deceleration assist device according to an embodiment of the present invention.

[0019] Figure 2A The diagram shows a scene in which a vehicle equipped with the deceleration assist device according to the embodiment of the present invention enters a curve.

[0020] Figure 2B The diagram shows a scene in which a vehicle equipped with the deceleration assist device according to the embodiment of the present invention travels on a curve.

[0021] Figure 3 This is a flowchart showing a routine executed by the deceleration assist device according to the embodiment of the present invention.

[0022] Figure 4 This is a flowchart showing a routine executed by the deceleration assist device according to the embodiment of the present invention.

[0023] Figure 5 The diagram shows a region where a target vehicle speed change condition or an execution prohibition condition is satisfied, which is determined by the lateral acceleration and the deceleration of the own vehicle.

[0024] Fig. 6A is with Figure 5 The same figure is a diagram showing an example of changes in the lateral acceleration and the deceleration of the own vehicle when the own vehicle turns right on the curve.

[0025] Figure 6B is with Figure 5 The same figure is a diagram showing an example of changes in the lateral acceleration and the deceleration of the own vehicle when the own vehicle turns right on the curve.

[0026] Figure 6C It is shown as Fig. 6A and Figure 6B As shown in FIG. 1 , this is a diagram showing changes in the target vehicle speed and the like when the lateral acceleration and the deceleration of the own vehicle change.

[0027] Fig. 7A is with Figure 5The same figure is a diagram showing another example of changes in the lateral acceleration and the deceleration of the own vehicle when the own vehicle turns right on the curve.

[0028] Figure 7B is with Figure 5 The same figure is a diagram showing another example of changes in the lateral acceleration and the deceleration of the own vehicle when the own vehicle turns right on the curve.

[0029] Figure 7C It is shown as Fig. 7A and Figure 7B As shown in FIG. 1 , this is a diagram showing changes in the target vehicle speed and the like when the lateral acceleration and the deceleration of the own vehicle change.

[0030] Figure 8 This is a diagram showing an example of transition of the target vehicle speed and the like when the lateral acceleration and the deceleration of the own vehicle change. DETAILED DESCRIPTION

[0031] Hereinafter, a deceleration assist device, a deceleration assist method, and a deceleration assist program according to embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 , a deceleration assist device 10 is shown. The deceleration assist device 10 is mounted on the own vehicle 100. The deceleration assist device 10 is described below by taking the case where the operator of the own vehicle 100 is a person who rides in the own vehicle 100 and drives the own vehicle 100 (that is, the driver of the own vehicle 100) as an example.

[0032] However, the operator of the own vehicle 100 may be a person who does not ride in the own vehicle 100 but drives the own vehicle 100 remotely (i.e., a remote operator of the own vehicle 100). When the operator of the own vehicle 100 is a remote operator, the deceleration assist device 10 is respectively mounted on the own vehicle 100 and a remote operation device provided outside the own vehicle 100 for remotely driving the own vehicle 100, and the functions of the deceleration assist device 10 described below are respectively shared and performed by the deceleration assist device 10 mounted on the own vehicle 100 and the deceleration assist device 10 mounted on the remote operation device.

[0033] like Figure 1 As shown, the deceleration assist device 10 is provided with an ECU (electronic control unit) 90 as a control device. The ECU 90 is provided with a microcomputer as a main part. The microcomputer includes a CPU, a storage medium such as a ROM, a RAM, and a non-volatile memory, and an interface, etc. The CPU implements various functions by executing instructions, programs, or routines stored in the storage medium. In particular, in this example, the deceleration assist device 10 stores programs for implementing various controls executed by the deceleration assist device 10 in the storage medium.

[0034] In this example, the deceleration assist device 10 includes only one ECU 90 , but may be configured to include a plurality of ECUs, with the functions of the deceleration assist device 10 described below being shared among the respective ECUs.

[0035] Furthermore, the deceleration assist device 10 may be configured to be able to update the program stored in the storage medium through wireless communication (for example, Internet communication) with an external device.

[0036] <Travel device>

[0037] The vehicle 100 is equipped with a travel device 20 . The travel device 20 includes a drive device 21 , a brake device 22 , and a steering device 23 .

[0038] The drive device 21 is a device that outputs a driving force (driving torque) applied to the own vehicle 100 to make the own vehicle 100 travel, such as an internal combustion engine and a motor. The drive device 21 is electrically connected to the ECU 90. The deceleration assist device 10 can control the driving force output from the drive device 21 by controlling the operation of the drive device 21.

[0039] The brake device 22 is a device that outputs a braking force (brake torque) applied to the own vehicle 100 to brake the own vehicle 100, and is, for example, a hydraulic brake device. The brake device 22 is electrically connected to the ECU 90. The deceleration assist device 10 can control the braking force output from the brake device 22 by controlling the operation of the brake device 22.

[0040] The steering device 23 is a device that outputs a steering force (steering torque) applied to the own vehicle 100 to steer the own vehicle 100, and is, for example, a power steering device. The steering device 23 is electrically connected to the ECU 90. The deceleration assist device 10 can control the steering force output from the steering device 23 by controlling the operation of the steering device 23.

[0041] <Sensors, etc.>

[0042] Furthermore, the own vehicle 100 is equipped with an accelerator pedal 31, an accelerator pedal operation amount sensor 32, a stop switch 33, a brake pedal 34, a brake pedal operation amount sensor 35, a steering wheel 36, a steering shaft 37, a steering angle sensor 38, a vehicle speed detection device 41, a longitudinal acceleration sensor 42, a lateral acceleration sensor 43, a yaw rate sensor 44, a peripheral information detection device 70 and a own vehicle position information detection device 80.

[0043] The accelerator pedal operation amount sensor 32 is a sensor for detecting the operation amount of the accelerator pedal 31, and is electrically connected to the ECU 90. The deceleration assist device 10 obtains the operation amount of the accelerator pedal 31 as the accelerator pedal operation amount AP through the accelerator pedal operation amount sensor 32. The deceleration assist device 10 obtains the required driving force (required driving torque) based on the accelerator pedal operation amount AP and the running speed of the own vehicle 100, and controls the operation of the drive device 21 so that the drive device 21 applies a driving force equivalent to the required driving force to the own vehicle 100.

[0044] The stop switch 33 is a sensor (brake sensor) for detecting operation of the brake pedal 34 by the driver of the own vehicle 100 and is electrically connected to the ECU 90. The deceleration assist device 10 detects operation of the brake pedal 34 by the driver of the own vehicle 100 through the stop switch 33.

[0045] The brake pedal operation amount sensor 35 is a sensor for detecting the operation amount of the brake pedal 34, and is electrically connected to the ECU 90. The deceleration assist device 10 obtains the operation amount of the brake pedal 34 as the brake pedal operation amount BP through the brake pedal operation amount sensor 35. The deceleration assist device 10 obtains the required braking force (required braking torque) based on the brake pedal operation amount BP, and controls the operation of the brake device 22 so that the brake device 22 applies a braking force equivalent to the required braking force to the own vehicle 100.

[0046] The steering angle sensor 38 is a sensor that detects the rotation angle of the steering shaft 37 relative to the neutral position, and is electrically connected to the ECU 90. The deceleration assist device 10 obtains the rotation angle of the steering shaft 37 as the steering angle θ through the steering angle sensor 38.

[0047] The deceleration assist device 10 obtains a required steering force (required steering torque) based on the steering angle θ and the traveling speed of the own vehicle 100 , and controls the operation of the steering device 23 so that a steering force corresponding to the required steering force is applied from the steering device 23 to the own vehicle 100 .

[0048] The vehicle speed detection device 41 is a device for detecting the running speed of the own vehicle 100, and is, for example, a wheel speed sensor. The vehicle speed detection device 41 is electrically connected to the ECU 90. The deceleration assist device 10 obtains the running speed of the own vehicle 100 as the own vehicle speed V through the vehicle speed detection device 41.

[0049] The longitudinal acceleration sensor 42 is a sensor for detecting acceleration in the longitudinal direction (longitudinal direction) of the own vehicle 100. The longitudinal acceleration sensor 42 is electrically connected to the ECU 90. The deceleration assist device 10 obtains the acceleration in the longitudinal direction of the own vehicle 100 as the longitudinal acceleration Gx through the longitudinal acceleration sensor 42.

[0050] The lateral acceleration sensor 43 is a sensor for detecting acceleration in the width direction (lateral direction) of the own vehicle 100. The lateral acceleration sensor 43 is electrically connected to the ECU 90. The deceleration assist device 10 obtains the acceleration in the width direction of the own vehicle 100 as the lateral acceleration Gy through the lateral acceleration sensor 43.

[0051] The yaw rate sensor 44 is a sensor that detects the yaw rate of the own vehicle 100. The yaw rate sensor 44 is electrically connected to the ECU 90. The deceleration assist device 10 obtains the yaw rate of the own vehicle 100 as the yaw rate YR through the yaw rate sensor 44.

[0052] The surrounding information detection device 70 is a device that detects information about the surroundings of the own vehicle 100 , and includes an image sensor 72 in this example.

[0053] The image sensor 72 is, for example, a camera, and is electrically connected to the ECU 90. The deceleration assist device 10 acquires image information about the periphery of the own vehicle 100 as the periphery detection information IS through the image sensor 72.

[0054] The own vehicle position information detection device 80 includes a GPS device 81 and a map information database 82 .

[0055] The GPS device 81 is a device that receives a so-called GPS signal, and is electrically connected to the ECU 90. The deceleration assist device 10 can obtain the GPS signal via the GPS device 81, and can identify (acquire) the position of the own vehicle 100 based on the obtained GPS signal.

[0056] The map information database 82 is a database storing map information IM, and is electrically connected to the ECU 90. The deceleration support device 10 can determine where the own vehicle 100 is located on the map indicated by the map information IM based on the position of the own vehicle 100 determined by the GPS signal and the map information IM.

[0057] <Operation of the deceleration assist device>

[0058] Next, the operation of the deceleration assist device 10 will be described. Figure 2A and Figure 2B As shown, the deceleration assist device 10 performs a deceleration control for controlling the operation of the brake device 22 to decelerate the own vehicle 100 when the own vehicle speed V is greater than the target vehicle speed Vtgt when the own vehicle 100 travels on the curve Rcurve. In other words, the deceleration assist device 10 performs a deceleration control for decelerating the own vehicle 100 when the own vehicle speed V is greater than the target vehicle speed Vtgt set as the target value of the own vehicle speed V when the own vehicle 100 travels on the curve Rcurve.

[0059] More specifically, the deceleration assist device 10 performs the following operations at predetermined time intervals: Figure 3 The routine shown in FIG. 1 is used to execute the deceleration control when a certain condition is satisfied. Therefore, when a predetermined timing is reached, the deceleration assist device 10 is turned on. Figure 3 The process of the routine shown starts at step S300 , and the process proceeds to step S305 , where it is determined whether a target vehicle speed change condition C1 (predetermined condition) is satisfied.

[0060] The target vehicle speed change condition C1 is a condition that “a decrease in the deceleration Gd of the own vehicle 100 is detected at a time point when the own vehicle 100 enters the curve Rcurve, and the deceleration Gd at that time point is equal to or greater than a predetermined deceleration Gd_th”.

[0061] In addition, "whether the own vehicle 100 has entered the curve Rcurve" is determined based on the lateral acceleration Gy, and when the lateral acceleration Gy becomes greater than zero or becomes greater than a predetermined value that is greater than zero but smaller, it is determined that the own vehicle 100 has entered the curve Rcurve. In addition, "whether the own vehicle 100 has entered the curve Rcurve" can also be determined based on the steering angle θ or the yaw rate YR. Alternatively, "whether the own vehicle 100 has entered the curve Rcurve" can also be determined based on the surrounding detection information IS, and can also be determined based on the position of the own vehicle 100 determined by the GPS signal and the map information IM.

[0062] In addition, the deceleration Gd of the own vehicle 100 is detected by the longitudinal acceleration sensor 42. At this time, the acceleration detected by the longitudinal acceleration sensor 42 takes a positive value when the own vehicle 100 is accelerating, and takes a negative value when the own vehicle 100 is decelerating. Therefore, the deceleration Gd of the own vehicle 100 is the absolute value of the negative longitudinal acceleration Gx detected by the longitudinal acceleration sensor 42.

[0063] In addition, even if the deceleration Gd of the own vehicle 100 cannot be obtained, when it is detected that the driver has released the brake pedal 34 at the time when the own vehicle 100 enters the curve Rcurve or at a time point immediately thereafter, there is a high probability that the deceleration Gd begins to decrease or has decreased at the time when the own vehicle 100 enters the curve Rcurve, so the target vehicle speed change condition C1 can also be set to the condition that "the driver released the brake pedal 34 at the time when the own vehicle 100 enters the curve Rcurve or at a time point immediately thereafter".

[0064] In this case, "whether the driver has released the brake pedal 34" is detected by the stop switch 33. That is, when the operation of the brake pedal 34 cannot be detected by the stop switch 33, it is determined that the driver has released the brake pedal 34. In addition, "whether the driver has released the brake pedal 34" can also be determined based on the brake pedal operation amount BP. In this case, when the brake pedal operation amount BP becomes zero, it is determined that the driver has released the brake pedal 34. Alternatively, "whether the driver has released the brake pedal 34" can also be determined based on the brake hydraulic pressure of the hydraulic brake device. In this case, when the brake hydraulic pressure becomes zero or below a predetermined value, it is determined that the driver has released the brake pedal 34.

[0065] If the deceleration assist device 10 determines "yes" in step S305, the process proceeds to step S310 to increase the target vehicle speed Vtgt by a predetermined value ΔV. In other words, the deceleration assist device 10 sets a vehicle speed that is greater than the current target vehicle speed Vtgt by a predetermined value ΔV as a new target vehicle speed Vtgt. Next, the deceleration assist device 10 proceeds to step S325.

[0066] The predetermined value ΔV may be a constant value or a variable value set based on at least one of the vehicle speed V, the yaw rate YR, the curvature of the curve Rcurve, and the like.

[0067] On the other hand, if the determination result in step S305 is "No", the deceleration assist device 10 proceeds to step S315 to determine whether the target vehicle speed recovery condition C2 is satisfied. The target vehicle speed recovery condition C2 is a condition that "after the vehicle 100 enters the curve Rcurve and the steering wheel 36 is rotated away from its neutral position, the steering wheel 36 is rotated toward its neutral position and the steering angle θ becomes less than a predetermined angle θth".

[0068] When the deceleration assist device 10 determines "yes" in step S315, the process proceeds to step S320, and when the target vehicle speed Vtgt is set to a vehicle speed greater than the predetermined value ΔV in step S310, the target vehicle speed Vtgt is reduced by the predetermined value ΔV. In other words, when the target vehicle speed Vtgt is set to a vehicle speed greater than the predetermined value ΔV in step S310, the deceleration assist device 10 sets a vehicle speed less than the current target vehicle speed Vtgt by the predetermined value ΔV as a new target vehicle speed Vtgt. That is, the deceleration assist device 10 restores the target vehicle speed Vtgt to the original target vehicle speed Vtgt. Next, the deceleration assist device 10 proceeds to step S325.

[0069] On the other hand, when the determination result in step S315 is “NO”, the deceleration assist device 10 directly proceeds the process to step S325 .

[0070] Next, the deceleration assist device 10 advances the process to step S325 and determines whether or not a deceleration control execution condition C3 is satisfied. The deceleration control execution condition C3 is a condition that "the own vehicle speed V is greater than the target vehicle speed Vtgt".

[0071] When the determination result in step S325 is YES, the deceleration assist device 10 advances the process to step S330 to execute the deceleration control. The deceleration control ends when the own vehicle speed V becomes equal to or lower than the target vehicle speed Vtgt.

[0072] Next, the deceleration assist device 10 advances the process to step S395 and temporarily ends the process of this routine.

[0073] On the other hand, when the determination result in step S325 is “NO”, the deceleration assist device 10 directly proceeds to step S395 and temporarily ends the processing of this routine.

[0074] In addition, although according to Figure 3 In the illustrated routine, the target vehicle speed Vtgt increases when the target vehicle speed changing condition C1 is satisfied. However, in the present invention, the target vehicle speed Vtgt only needs to increase during the period from when the target vehicle speed changing condition C1 is satisfied until the deceleration Gd becomes zero.

[0075] Alternatively, the deceleration assist device 10 may also execute the deceleration assist operation at predetermined time intervals. Figure 4 In this case, when a predetermined timing is reached, the deceleration assist device 10 is turned on and off. Figure 4 The process of the routine shown starts at step S400, and the process proceeds to step S405, where it is determined whether the execution prohibition condition C4 is satisfied. In this example, the execution prohibition condition C4 is the same condition as the target vehicle speed change condition C1.

[0076] When the deceleration assist device 10 determines "yes" in step S405, the process proceeds to step S410, and the value of the execution prohibition flag X is set to "1". Next, the deceleration assist device 10 proceeds to step S425. Thus, the execution of the deceleration control is prohibited. Therefore, even if the own vehicle speed V is greater than the target vehicle speed Vtgt, the deceleration control is not executed.

[0077] On the other hand, when the determination result in step S405 is "NO", the deceleration assist device 10 advances the process to step S415 to determine whether the execution permission condition C5 is satisfied. In this example, the execution permission condition C5 is the same condition as the target vehicle speed recovery condition C2.

[0078] When the determination in step S415 is “YES”, the deceleration assist device 10 advances the process to step S420 and sets the value of the execution prohibition flag X to “0”. Next, the deceleration assist device 10 advances the process to step S425. Thus, the prohibition of execution of the deceleration control is released.

[0079] On the other hand, when the determination result in step S415 is “NO”, the deceleration assist device 10 directly proceeds the process to step S425 .

[0080] Next, the deceleration assist device 10 advances the process to step S425 and determines whether the value of the execution prohibition flag X is set to “0”.

[0081] When the determination result in step S425 is “YES”, the deceleration assist device 10 advances the process to step S430 to determine whether the deceleration control execution condition C3 is satisfied.

[0082] When the determination result in step S430 is “YES”, the deceleration assist device 10 advances the process to step S435 to execute the deceleration control. Next, the deceleration assist device 10 advances the process to step S495 to temporarily terminate the process of this routine.

[0083] On the other hand, when the determination result in step S425 or step S430 is “NO”, the deceleration assist device 10 directly advances the process to step S495 and temporarily ends the process of this routine.

[0084] In addition, according to Figure 4 In the routine shown, the execution of the deceleration control is prohibited when the execution prohibition condition C4 is satisfied. However, in the present invention, the execution of the deceleration control may be prohibited only during the period from when the execution prohibition condition C4 is satisfied until the deceleration Gd becomes zero.

[0085] The above is the operation of the deceleration assist device 10 .

[0086] When the reduction in the deceleration Gd of the own vehicle 100 is detected at the time when the own vehicle 100 enters the curve Rcurve and there is a remaining deceleration Gd at that time, the driver determines that the speed of the own vehicle 100 has been sufficiently reduced and there is a sufficient load remaining on the front wheels of the own vehicle 100, so there is a high possibility that the deceleration of the own vehicle 100 under the deceleration control is not required. If the deceleration control is executed at this time, the driver may feel uncomfortable.

[0087] According to the deceleration assist device 10, for example, Figure 5 As shown, when the deceleration Gd, which has increased to a certain value Gd_1 greater than the predetermined deceleration Gd_th, decreases in the area AREA_R or the area AREA_L after the vehicle 100 enters the curve Rcurve, the target vehicle speed Vtgt is increased by a predetermined value ΔV or execution of the deceleration control is prohibited.

[0088] exist Figure 5 In the graph shown, the horizontal axis represents the lateral acceleration Gy, and the vertical axis represents the deceleration Gd. Figure 5 In the graph shown, positive values ​​on the horizontal axis are lateral acceleration Gy when the host vehicle 100 turns right, and negative values ​​on the horizontal axis are lateral acceleration Gy when the host vehicle 100 turns left.

[0089] For example, when the vehicle 100 enters the curve Rcurve and turns right, the deceleration Gd is as follows: Fig. 6A After rising to a certain value Gd_1 as shown by the center line L1, the deceleration Gd starts to decrease when the vehicle 100 enters the curve Rcurve. Figure 6B When the deceleration Gd decreases while the line L2 shown in FIG. Figure 6C As shown, the target vehicle speed Vtgt is increased by a predetermined value ΔV.

[0090] That is, in Figure 6C In the example shown, after the deceleration Gd starts to increase at time t60, it reaches a certain value Gd_1 greater than the predetermined deceleration Gd_th, and then at time t61, the vehicle 100 enters the curve Rcurve and the lateral acceleration Gy starts to increase, and the deceleration Gd starts to decrease, and then at time t62, the deceleration Gd becomes zero. In addition, the lateral acceleration Gy continues to increase during the period from time t61 to time t63, and becomes constant after time t63.

[0091] In this case, at time t61, when the vehicle 100 enters the curve Rcurve, a decrease in the deceleration Gd is detected and the deceleration Gd at that time is equal to or greater than a predetermined deceleration Gd_th. Therefore, at that time, the target vehicle speed Vtgt is changed from the value Vtgt_1 to the value Vtgt_2 which is greater than the predetermined value ΔV.

[0092] In addition, when the vehicle 100 enters the curve Rcurve and turns right, the deceleration Gd is as follows: Fig. 7AAfter rising to a certain value Gd_1 as shown by the center line L1, when the deceleration Gd decreases as shown by the line L3, the vehicle 100 enters the curve Rcurve, and the lateral acceleration Gy moves along Figure 7B When the deceleration Gd decreases while the line L4 shown in FIG. Figure 7C As shown, the target vehicle speed Vtgt is increased by a predetermined value ΔV.

[0093] That is, in Figure 7C In the example shown, after the deceleration Gd starts to increase at time t70, it reaches a certain value Gd_1 greater than the predetermined deceleration Gd_th, and then the deceleration Gd starts to decrease at time t71. Then, at time t72 when the deceleration Gd is greater than the predetermined deceleration Gd_th, the vehicle 100 enters the curve Rcurve and the lateral acceleration Gy starts to increase, and then at time t73 the deceleration Gd becomes zero. In addition, the lateral acceleration Gy continues to increase from time t72 to time t74, and becomes constant after time t74.

[0094] In this case, at time t72 when the vehicle 100 enters the curve Rcurve, a decrease in the deceleration Gd is detected and the deceleration Gd at that time is greater than the predetermined deceleration Gd_th. Therefore, at that time, the target vehicle speed Vtgt is changed from the value Vtgt_1 to the value Vtgt_2 which is greater than the predetermined value ΔV.

[0095] As described above, according to the deceleration assist device 10, when a decrease in the deceleration Gd of the own vehicle 100 is detected at the time when the own vehicle 100 enters the curve Rcurve and the deceleration Gd at the time is greater than the predetermined deceleration Gd_th, and the driver determines that the own vehicle speed V has been sufficiently reduced, and it is highly likely that the deceleration of the own vehicle 100 under the deceleration control is not required, the target vehicle speed Vtgt is increased by the predetermined value ΔV, or the deceleration control is not performed even if the own vehicle speed V is greater than the target vehicle speed Vtgt. Therefore, it is possible to suppress the situation where the driver feels uncomfortable due to the deceleration control being performed when the own vehicle 100 travels on the curve Rcurve.

[0096] In addition, the present invention is not limited to the above-described embodiment, and various modifications can be adopted within the scope of the present invention.

[0097] For example, the target vehicle speed change condition C1 may be a condition that "after the vehicle 100 enters the curve Rcurve, a deceleration of the deceleration Gd is detected while the vehicle 100 travels along the curve Rcurve, and the deceleration Gd at that time is equal to or greater than a predetermined deceleration Gd_th".

[0098] In this case, the target vehicle speed Vtgt is set as Figure 8 As shown, the predetermined value ΔV is increased. Figure 8 In the example shown, the deceleration Gd starts to increase at time t80 and reaches a certain value Gd_1 greater than the predetermined deceleration Gd_th. Then, at time t81, the vehicle 100 enters the curve Rcurve and the lateral acceleration Gy starts to increase. Then, at time t82, the deceleration Gd that is greater than the predetermined deceleration Gd_th starts to decrease. Then, at time t83, the deceleration Gd becomes zero. In addition, the lateral acceleration Gy continues to increase from time t81 to time t84 and becomes constant after time t84.

[0099] In this case, after the vehicle 100 enters the curve Rcurve at time t81, at time t82 while the vehicle 100 is traveling along the curve Rcurve, a decrease in the deceleration Gd is detected and the deceleration Gd at this time point is greater than the predetermined deceleration Gd_th. Therefore, the target vehicle speed change condition C1 is satisfied at this time point, so the target vehicle speed Vtgt is changed from the value Vtgt_1 to the value Vtgt_2 which is greater than the predetermined value ΔV.

[0100] Therefore, in the present invention, the target vehicle speed change condition C1 only needs to be the condition that "a decrease in the deceleration Gd is detected when the host vehicle 100 travels on the curve Rcurve, and the deceleration Gd at that time is equal to or greater than the predetermined deceleration Gd_th".

[0101] In the present invention, the target vehicle speed change condition C1 may be at least a condition that a decrease in the deceleration Gd is detected when the host vehicle 100 travels on the curve Rcurve.

[0102] In addition, the present invention can also be applied to a vehicle that can be driven by manual driving operation and automatic driving control, or a vehicle that is driven only by manual driving operation. When the present invention is applied to such a vehicle, it is used when the vehicle is driven by manual driving operation. Manual driving operation is a driving operation performed by the operator himself to drive the vehicle. Automatic driving control is a control in which the operator does not perform the driving operation for driving the vehicle himself, but the vehicle is automatically driven by a control device such as an ECU.

Claims

1. A deceleration assist device comprising a control device for executing deceleration control for decelerating the vehicle when a vehicle speed is greater than a target vehicle speed set as a target value of the vehicle speed when the vehicle is traveling on a curve, The control device is configured to increase the target vehicle speed by a predetermined value when a predetermined condition is satisfied that a decrease in the deceleration of the vehicle is detected while the vehicle is traveling on the curve, or not to perform the deceleration control even if the vehicle speed is greater than the target vehicle speed.

2. The deceleration assist device according to claim 1, The predetermined condition includes a condition that the deceleration of the vehicle is equal to or greater than a predetermined deceleration at a time point when a decrease in the deceleration of the vehicle is detected.

3. The deceleration assist device according to claim 1 or 2, The predetermined condition includes a condition that a decrease in the deceleration of the vehicle is detected at a point in time when the vehicle enters the curve.

4. A deceleration assist method, comprising: executing a deceleration control to decelerate the vehicle when a vehicle speed is greater than a target vehicle speed set as a target value of the vehicle speed when the vehicle is traveling on a curve, The deceleration assist method includes the steps of increasing the target vehicle speed by a predetermined value when a predetermined condition is satisfied that a decrease in the deceleration of the vehicle is detected when the vehicle travels on the curve, or not performing the deceleration control even if the vehicle speed is greater than the target vehicle speed.

5. A deceleration assist program for executing a deceleration control for decelerating the vehicle when the vehicle speed is greater than a target vehicle speed set as a target value of the vehicle speed when the vehicle is traveling on a curve, The deceleration assist program is configured to increase the target vehicle speed by a predetermined value or not perform the deceleration control even if the vehicle speed is greater than the target vehicle speed when a predetermined condition is satisfied that a decrease in the vehicle deceleration is detected while the vehicle is traveling on the curve.

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