In-vehicle control device

Abstract

To suppress a feeling of strangeness from being given to a driver when an accelerator is turned off.SOLUTION: An on-vehicle control device, which is mounted on a vehicle and executes control of decelerating the vehicle when an accelerator is turned off, sets a reference deceleration index so that the index becomes higher as an inter-vehicle distance from a preceding vehicle becomes shorter, applies, to the reference deceleration index, a gradually changing process for changing the deceleration index when a lost condition for the preceding vehicle is satisfied, more gently in comparison with when the lost condition is not satisfied, so as to set a deceleration index, and executes deceleration control so that the vehicle decelerates at higher deceleration as the deceleration index is higher.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an in-vehicle control device.

Background Art

[0002] Conventionally, as this type of in-vehicle control device, in a control device that performs inter-vehicle distance control for controlling the acceleration and deceleration of a host vehicle so as to maintain the inter-vehicle distance from a preceding vehicle at a predetermined target inter-vehicle distance, a control device has been proposed in which the form of starting or canceling the inter-vehicle distance control is variable according to the driving state (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the host vehicle is traveling based on an accelerator-off operation or a brake operation, when the preceding vehicle is lost during accelerator-off, if deceleration control similar to when the preceding vehicle is present is executed, the driver may feel discomfort.

[0005] The in-vehicle control device of the present invention mainly aims to suppress giving discomfort to the driver during accelerator-off.

Means for Solving the Problems

[0006] The in-vehicle control device of the present invention has adopted the following means in order to achieve the above main object.

[0007] The first in-vehicle control device of the present invention is an in-vehicle control device mounted on a vehicle and performing deceleration control of the vehicle during accelerator-off, during accelerator-off, Set a basic deceleration index so that it increases as the distance to the vehicle ahead decreases. Apply a creep process to the basic deceleration index to gently change the deceleration index when the lost condition of the vehicle ahead is satisfied compared to when it is not satisfied, and set the deceleration index. Execute the deceleration control so that the vehicle decelerates at a higher deceleration as the deceleration index increases. This is the gist.

[0008] In the first in-vehicle control device of the present invention, when the accelerator is off, a basic deceleration index is set so that it increases as the distance to the vehicle ahead decreases. A creep process is applied to the basic deceleration index to gently change the deceleration index when the lost condition of the vehicle ahead is satisfied compared to when it is not satisfied, and the deceleration index is set. The deceleration control is executed so that the vehicle decelerates at a higher deceleration as the deceleration index increases. As a result, when the lost condition is satisfied, the deceleration index and the deceleration of the vehicle can be gently changed with respect to the change in the basic deceleration index based on the distance to the vehicle ahead compared to when the lost condition is not satisfied. As a result, when the lost condition of the vehicle ahead switches from not being satisfied to being satisfied and the basic deceleration index suddenly decreases, it is possible to suppress a sudden decrease in the deceleration index and the deceleration of the vehicle, suppress giving a sense of discomfort to the driver, and give a relatively natural deceleration feeling.

[0009] In the first in-vehicle control device of the present invention, as the creep process for the basic deceleration index, a smoothing process using a smoothing constant that becomes larger when the lost condition is satisfied compared to when the lost condition is not satisfied may be applied to set the deceleration index.

[0010] The second in-vehicle control device of the present invention Is an in-vehicle control device mounted on a vehicle that executes deceleration control of the vehicle when the accelerator is off, When the accelerator is off, Set a basic deceleration index so that it increases as the distance to the vehicle ahead decreases. When the lost condition of the preceding vehicle does not hold, a deceleration index is set based on the basic deceleration index, and when the lost condition holds, the deceleration index is maintained. The deceleration control is executed such that the vehicle decelerates at a higher deceleration as the deceleration index is higher. This is the gist.

[0011] In the second in-vehicle control device of the present invention, when the accelerator is off, the basic deceleration index is set so as to increase as the inter-vehicle distance from the preceding vehicle becomes shorter. When the lost condition of the preceding vehicle does not hold, a deceleration index is set based on the basic deceleration index. When the lost condition holds, the deceleration index is maintained, and deceleration control is executed such that the vehicle decelerates at a higher deceleration as the deceleration index is higher. Thereby, when the lost condition holds, by maintaining the deceleration index with respect to the change in the basic deceleration index based on the inter-vehicle distance from the preceding vehicle, it is possible to suppress a sudden change in the deceleration of the vehicle. As a result, when the lost condition of the preceding vehicle switches from not holding to holding and the basic deceleration index suddenly decreases, by maintaining the deceleration index, it is possible to suppress a sudden decrease in the deceleration of the vehicle, suppress giving a sense of discomfort to the driver, and give a relatively natural deceleration feeling.

[0012] In the second in-vehicle control device of the present invention, when the lost condition does not hold when the accelerator is off, the basic deceleration index may be set to the deceleration index, or the deceleration index may be set by performing a gradual change process on the basic deceleration index.

[0013] In the first or second in-vehicle control device of the present invention, the lost condition may include at least one of a condition that the preceding vehicle does not exist within a predetermined distance and a condition that an increase amount per unit time of the inter-vehicle distance from the preceding vehicle is equal to or greater than a predetermined increase amount.

[0014] In the first or second in-vehicle control device of the present invention, the basic deceleration index may be set such that it increases as the inter-vehicle distance from the preceding vehicle becomes shorter, increases as the vehicle speed of the vehicle becomes higher, and increases as the relative vehicle speed of the vehicle with respect to the vehicle speed of the preceding vehicle becomes higher. By doing so, the basic deceleration index can be set more appropriately.

[0015] In the first or second in-vehicle control device of the present invention, the deceleration control may be executed such that the vehicle decelerates at a higher deceleration as the deceleration index increases and at a higher deceleration as the vehicle speed of the vehicle increases. By doing so, the deceleration of the vehicle can be controlled more appropriately.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0017] Next, embodiments for carrying out the present invention will be described using examples.

Example

[0018] FIG. 1 is a configuration diagram showing an outline of the configuration of an electric vehicle 20 equipped with an in-vehicle control device as an embodiment of the present invention. As shown in the figure, the electric vehicle 20 of the embodiment includes a traveling motor 62 connected to drive wheels, a battery 40 that exchanges power with the motor 62, and an electronic control unit 50 that controls the entire vehicle. In the embodiment, the electronic control unit 50 corresponds to the in-vehicle control device.

[0019] In addition to the motor 62, the battery 40, and the electronic control unit 50, the electric vehicle 20 of the embodiment further includes an ignition switch 22, a GPS (Global Positioning System) 24, an in-vehicle camera 26, a millimeter-wave radar 28, a vehicle speed sensor 30, an acceleration sensor 32, an accelerator sensor 34, a brake sensor 36, a battery actuator 38, a battery 40, a drive actuator 60, a brake actuator 64, a brake device 66, a display device 68, a meter 70, and a navigation system 80.

[0020] The GPS 24 detects the position of the vehicle based on signals transmitted from a plurality of GPS satellites. The in-vehicle camera 26 is a camera that images the surroundings of the vehicle, and examples include a front camera that images the front of the vehicle and a rear camera that images the rear of the vehicle. The millimeter-wave radar 28 detects the inter-vehicle distance and relative vehicle speed between the host vehicle and the vehicle ahead, or the inter-vehicle distance and relative vehicle speed between the host vehicle and the vehicle behind.

[0021] The vehicle speed sensor 30 detects the vehicle speed based on, for example, the wheel speed. The acceleration sensor 32 detects the acceleration of the vehicle in the longitudinal direction or the acceleration of the vehicle in the lateral direction (sideways). The accelerator sensor 34 detects the accelerator opening, etc., as the amount of depression of the driver's accelerator pedal. The brake sensor 36 detects the brake position, etc., as the amount of depression of the driver's brake pedal.

[0022] The battery actuator 38 detects the voltage, current, and temperature of the battery 40, and manages the battery 40 based on these. The battery actuator 38 calculates the state of charge SOC as the ratio of the remaining charge capacity to the total charge capacity based on the current of the battery 40. The battery 40 is configured as a rechargeable secondary battery, and for example, a lithium-ion battery, a nickel-metal hydride battery, a lead-acid battery, etc. can be used.

[0023] The electronic control unit 50 includes a microcomputer having a CPU 51, a ROM 52, a RAM 53, a flash memory 54, an input / output port, and a communication port. When the brake pedal is not depressed, the electronic control unit 50 sets the target driving force (positive driving force) or the target braking force (negative driving force) of the motor 62 based on the accelerator opening from the accelerator sensor 34 and the vehicle speed from the vehicle speed sensor 30, and transmits the set target driving force or target braking force to the drive actuator 60. Also, when the brake pedal is depressed, the electronic control unit 50 sets the target braking force of the brake device 66 based on the brake position from the brake sensor 36 and the vehicle speed from the vehicle speed sensor 30, and transmits the set target braking force to the brake actuator 64.

[0024] The drive actuator 60 drives and controls the motor 62 so as to run by a target driving force or a target braking force set by the electronic control unit 50. The motor 62 can use, for example, a synchronous generator motor or the like. This motor 62 is connected to the battery 40 via an inverter, and can output a driving force using the electric power supplied from the battery 40, or supply the generated electric power to the battery 40.

[0025] The brake actuator 64 controls the brake device 66 so that the target braking force set by the electronic control unit 50 acts on the vehicle. The brake device 66 is configured as, for example, a hydraulically driven friction brake.

[0026] The display device 68 is incorporated in, for example, the installation panel in front of the driver's seat, and displays various information. The meter 70 is incorporated in, for example, the installation panel in front of the driver's seat.

[0027] The navigation system 80 is a system that guides the own vehicle to a set destination, and includes a map information database 82 and a display unit 84. In the map information database 82, as map information, distance information, width information, type information (general road, highway), legal speed information, etc. of roads in each section are stored. The display unit 84 displays map information and the like. When a destination is set, the navigation system 80 sets a driving route based on the information of the destination, the information of the current location (the position of the current own vehicle) acquired by the GPS 24, and the information stored in the map information database 82, and displays the set driving route on the display unit 84 to perform route guidance.

[0028] Next, the operation of the electric vehicle 20 of the embodiment configured in this way, particularly the operation when the accelerator is off, will be described. FIG. 2 is a flowchart showing an example of a processing routine when the accelerator is off, which is executed by the electronic control unit 50. This routine is repeatedly executed when the accelerator is off.

[0029] When the accelerator-off processing routine in FIG. 2 is executed, the electronic control unit 50 first inputs data such as the vehicle speed Vs of the host vehicle, the inter-vehicle distance d between the host vehicle and the preceding vehicle, the relative vehicle speed Vr (the vehicle speed of the host vehicle with respect to the preceding vehicle), and the inter-vehicle distance increase rate Δd (step S100). Here, as the vehicle speed Vs, for example, the value detected by the vehicle speed sensor 30 can be used. As the inter-vehicle distance d and the relative vehicle speed Vr, for example, the values detected by the millimeter wave radar 28 can be used. In the embodiment, when there is no preceding vehicle within a predetermined distance d1 (for example, about 500 m to 1 km) ahead of the host vehicle, the millimeter wave radar 28 sets a distance slightly longer than the predetermined distance d1 for the inter-vehicle distance d for each of the following processes. The inter-vehicle distance increase rate Δd is the increase amount of the inter-vehicle distance d per unit time. For example, a value obtained by dividing the value obtained by subtracting the previous inter-vehicle distance (previous Dv) from the current inter-vehicle distance (current Dv) by the execution interval Δt of this routine can be used.

[0030] After inputting the data in this way, the approach feeling index kp is calculated by the formula (1) using the input vehicle speed Vs, inter-vehicle distance d, and relative vehicle speed Vr (step S110). Here, the approach feeling index kp is an index indicating the degree of approach feeling that the driver feels when the host vehicle is approaching the preceding vehicle. In the formula (1), the constant α and the constant n are determined by experiments, analyses, machine learning, etc. When the constant n is 1, "Vr / d" means the reciprocal of the time to collision (TTC: Time To Collision), and when the constant α and the constant n are 1, "Vs / d" is the reciprocal of the time (THW: Time Headway) until the host vehicle reaches the current position of the preceding vehicle. Therefore, the higher the approach feeling index kp, specifically, the shorter the inter-vehicle distance d, the higher the vehicle speed Vs, and the higher the relative vehicle speed Vr, the higher the approach feeling that the driver feels.

[0031] kp=(Vr+α·Vs) / dn (1)

[0032] Subsequently, based on the approach index kp, a basic deceleration index kdtmp as the basic value of the deceleration index kd is set (step S120). Here, the basic deceleration index kdtmp can be set, for example, by applying the approach index kp to a basic deceleration index setting map determined in advance by experiments, analyses, or machine learning as the relationship between the approach index kp and the basic deceleration index kdtmp. FIG. 3 is an explanatory diagram showing an example of the basic deceleration index setting map. As shown in the figure, the basic deceleration index kdtmp is set such that the higher the approach index kp within the range of values of 0 or more and 1 or less, the higher it becomes. Specifically, the basic deceleration index kdtmp is set to a value of 0 in the region where the approach index kp is less than or equal to the value kp1, set to a value of 1 in the region where the approach index kp is greater than or equal to the value kp2 which is higher than the value kp1, and in the region where the approach index kp is higher than the value kp1 and less than the value kp2, it is set to increase from the value 0 towards the value 1 as the approach index kp increases.

[0033] Then, the input inter-vehicle distance d is compared with the above-described predetermined distance d1 (step S130), and the inter-vehicle distance increase rate Δd is compared with the threshold value Δdref (step S140). Here, the processes of steps S130 and S140 are processes for determining whether or not the lost condition of the preceding vehicle is satisfied. Examples of the case where the preceding vehicle is lost include, for example, the case where the preceding vehicle is lost on a curved road, the case where the preceding vehicle is lost due to turning left or right or changing lanes, the case where the preceding vehicle is lost due to sudden acceleration, etc. In the embodiment, the case where no preceding vehicle exists within the predetermined distance d1 in front of the host vehicle from the start of accelerator-off is also included in the case where the preceding vehicle is lost. Specifically, the process of step S130 is a process for determining whether or not the lost condition of the preceding vehicle is satisfied by determining whether or not a preceding vehicle exists within the predetermined distance d1 in front of the host vehicle. Also, the process of step S140 is a process for determining whether or not the lost condition of the preceding vehicle is satisfied by determining whether or not the inter-vehicle distance d between the host vehicle and the preceding vehicle is rapidly increasing.

[0034] When the inter-vehicle distance d is less than or equal to a predetermined distance d1 in step S130 and the inter-vehicle distance increase rate Δd is less than or equal to a threshold value dref in step S140, since there is a preceding vehicle within a predetermined distance d1 in front of the host vehicle and the inter-vehicle distance d between the host vehicle and the preceding vehicle is not increasing rapidly, it is determined that the lost condition of the preceding vehicle is not satisfied (step S150), and a relatively small value Ns1 is set for the smoothing constant Ns (step S160).

[0035] When the smoothing constant Ns is set in this way, a smoothing process using the smoothing constant Ns is performed on the basic deceleration index kdtmp to set the deceleration index kd (step S190). Here, the deceleration index kd can be calculated, for example, by formula (2) using the basic deceleration index kdtmp, the previous deceleration index (previous kd), and the smoothing constant Ns.

[0036] kd = previous kd+(kdtmp - previous kd) / Ns (2)

[0037] Subsequently, a target deceleration Dv* is set based on the vehicle speed Vs and the deceleration index kd (step S200), and this routine ends. Here, the target deceleration Dv* can be calculated by Equation (3) using, for example, the upper limit deceleration Dvmax and the lower limit deceleration Dvmin set based on the vehicle speed Vs, and the set upper limit deceleration Dvmax, the lower limit deceleration Dvmin, and the deceleration index kd. The upper limit deceleration Dvmax and the lower limit deceleration Dvmin can be set, for example, by applying the vehicle speed Vs to a map for setting the upper and lower limit decelerations determined in advance by experiments, analysis, or machine learning as the relationship between the vehicle speed Vs, the upper limit deceleration Dvmax, and the lower limit deceleration Dvmin. FIG. 4 is an explanatory diagram showing an example of the map for setting the upper and lower limit decelerations. As shown in the figure, the upper limit deceleration Dvmax and the lower limit deceleration Dvmin are set to increase as the vehicle speed Vs increases. This is to give the driver a deceleration feeling corresponding to the vehicle speed Vs. By the process of step S200, the target deceleration Dv* is set to increase as the vehicle speed V increases and as the deceleration index kd increases. Therefore, by the processes of steps S120 to S200, as the approach index kp increases, the basic deceleration index kdtmp increases, the deceleration index kd increases, and the target deceleration Dv* increases.

[0038] Dv* = Dvmax·kd + Dvmin·(1 - kd) (3)

[0039] When the target deceleration Dv* is set in this way, the target braking force of the motor 62 is set so that the vehicle decelerates at the target deceleration Dv* by the braking force from the motor 62, and the set target braking force is transmitted to the drive actuator 60. The drive actuator 60 drives and controls the motor 62 to run according to the received target braking force. When the target deceleration Dv* is relatively large or the charging of the battery 40 is restricted, etc., in addition to or instead of the motor 62, the braking device 66 may be controlled so that the vehicle decelerates at the target deceleration Dv* by the braking force from the braking device 66 in addition to or instead of the motor 62.

[0040] When the inter-vehicle distance d is longer than the predetermined distance d1 in step S130, it is determined that the lost condition of the preceding vehicle is satisfied because there is no preceding vehicle within the predetermined distance d1 ahead of the host vehicle (step S170). A value Ns2 larger than the value Ns1 is set for the smoothing constant Ns (step S180), and the processes after step S190 are executed. Also, when the inter-vehicle distance increase rate Δd is less than the threshold value dref in step S140, it is determined that the lost condition of the preceding vehicle is satisfied because the inter-vehicle distance d between the host vehicle and the preceding vehicle has increased rapidly (step S170). A value Ns2 larger than the value Ns1 is set for the smoothing constant Ns (step S180), and the processes after step S190 are executed. Therefore, when the lost condition of the preceding vehicle is satisfied, that is, when the value Ns2 is set for the smoothing constant Ns, as compared with when the lost condition of the preceding vehicle is not satisfied, that is, when the value Ns1 is set for the smoothing constant Ns, the deceleration index kd and the target deceleration Dv* change gently with respect to the changes in the approach feeling index kp and the basic deceleration index kdtmp. As a result, when the preceding vehicle is lost, for example, when the preceding vehicle is lost on a curved road, when the preceding vehicle is lost due to a left turn, a right turn, or a lane change, or when the preceding vehicle is lost due to a sudden acceleration, it is possible to suppress a sudden decrease in the deceleration index kd and the target deceleration Dv* accompanying a sudden decrease in the approach feeling index kp and the basic deceleration index kdtmp, suppress a sudden decrease in the deceleration of the vehicle, and suppress giving a sense of discomfort to the driver, thereby giving a relatively natural deceleration feeling.

[0041] FIG. 5 is a time chart showing an example of the success or failure of the lost condition, the approach feeling index kp, the basic deceleration index kdtmp, the smoothing constant Ns, the deceleration index kd, and the target deceleration Dv* when the accelerator is off in the embodiment and the first comparative example. In the figure, for the smoothing constant Ns, the deceleration index kdtmp, and the target deceleration Dv*, the solid line indicates the state of the embodiment, and the dashed-dotted line indicates the state of the first comparative example. In the first comparative example, it is assumed that the value Ns1 is set for the smoothing constant Ns without considering the success or failure of the lost condition.

[0042] In the embodiment and the first comparative example, when the lost condition is not satisfied when the accelerator is off (before time t1), a smoothing process is performed on the basic deceleration index kdtmp based on the approach sense index kp by using the value Ns1 as the smoothing constant Ns to set the deceleration index kd. Based on this deceleration index kd, the target deceleration Dv* is set to control the motor 62. Thereby, the deceleration index kd and the target deceleration Dv* can be changed relatively quickly in response to changes in the approach sense index kp and the basic deceleration index kdtmp based on changes in the inter-vehicle distance d and the like from the preceding vehicle, and the deceleration of the vehicle can be adjusted quickly.

[0043] In the first comparative example, when the lost condition is satisfied (at time t1) during the continuation of the accelerator-off, such as when the preceding vehicle no longer exists within a predetermined distance d1 ahead of the host vehicle, and the approach sense index kp and thus the basic deceleration index kdtmp suddenly decrease, even in this case, by performing a smoothing process on the basic deceleration index kdtmp by using the value Ns1 as the smoothing constant Ns to set the deceleration index kd, the deceleration index kd and the target deceleration Dv* will also suddenly decrease. Therefore, when the preceding vehicle is lost, the deceleration of the vehicle suddenly decreases, which may give the driver a sense of discomfort. In contrast, in the embodiment, when the lost condition is satisfied (at time t1) and the approach sense index kp and thus the basic deceleration index kdtmp suddenly decrease, by performing a smoothing process on the basic deceleration index kdtmp by using the value Ns2 as the smoothing constant Ns to set the deceleration index kd, it is possible to suppress the sudden decrease of the deceleration index kd and the target deceleration Dv*. Thereby, when the preceding vehicle is lost, it is possible to suppress the sudden decrease of the deceleration of the vehicle, suppress giving the driver a sense of discomfort, and give a relatively natural deceleration feeling.

[0044] In the electronic control unit 50 mounted on the electric vehicle 20 of the embodiment described above, when the accelerator is off, an approach index kp is set so that it becomes higher as the inter-vehicle distance d from the vehicle ahead becomes shorter, and a basic deceleration index kdtmp is set so that it becomes higher as the set approach index kp becomes higher. Subsequently, when the loss condition is not satisfied, a value Ns1 is set for the smoothing constant Ns, and when the loss condition is satisfied, a value Ns2 larger than the value Ns1 is set for the smoothing constant Ns, and a smoothing process using the smoothing constant Ns is performed on the basic deceleration index kdtmp to set the deceleration index kd. Then, a target deceleration Dv* is set so that it becomes higher as the deceleration index kd becomes higher, and the motor 62 is controlled so that the vehicle decelerates at the target deceleration Dv*. In this way, when the loss condition is satisfied, by gently changing the deceleration index kd and the target deceleration Dv* compared to when the loss condition is not satisfied, when the vehicle ahead is lost, it is possible to suppress a sudden decrease in the deceleration of the vehicle, suppress giving a sense of discomfort to the driver, and give a relatively natural deceleration feeling.

[0045] In the electronic control unit 50 mounted on the electric vehicle 20 of the embodiment, when the loss condition is not satisfied, a value Ns1 is set for the smoothing constant Ns, and when the loss condition is satisfied, a value Ns2 larger than the value Ns1 is set for the smoothing constant Ns, and a smoothing process using the smoothing constant Ns is performed on the basic deceleration index kdtmp to set the deceleration index kd. However, the present invention is not limited to this, and any process may be used as long as a creep process is performed on the basic deceleration index kdtmp to gently change the deceleration index kd when the loss condition is satisfied compared to when the loss condition is not satisfied, thereby setting the deceleration index kd. Examples of the creep process include various filter processes such as FIR (Finite Impulse Respose) filter process, IIR (Infinite Impulse Response) filter process, and low-pass filter process, and rate process. In various filter processes, it is conceivable to change the time constant or cut-off frequency based on the presence or absence of the loss condition, and in the rate process, it is conceivable to change the rate value based on the presence or absence of the loss condition.

[0046] In the electronic control unit 50 mounted on the electric vehicle 20 of the embodiment, it is assumed that the accelerator-off processing routine in FIG. 2 is executed. However, instead of this, the accelerator-off processing routine in FIG. 6 may be executed. The accelerator-off processing routine in FIG. 6 is different from the accelerator-off processing routine in FIG. 2 in that the processes in steps S160, S180, and S190 are replaced with the processes in steps S300 to S320. Therefore, for the same processes as those in the accelerator-off processing routine in FIG. 2 in the accelerator-off processing routine in FIG. 6, the same step numbers are assigned, and detailed descriptions are omitted.

[0047] In the accelerator-off processing routine in FIG. 6, when the electronic control unit 50 determines in step S150 that the lost condition of the preceding vehicle is not satisfied, the basic deceleration index kdtmp set in step S120 is set as the deceleration index kd (step S310), the target deceleration Dv* is set based on the deceleration index kd (step S200), and this routine is terminated.

[0048] Also, when it is determined in step S170 that the lost condition of the preceding vehicle is satisfied, it is determined whether it is immediately after the start of the accelerator-off (the first execution of the repetition of this routine) (step S300). When it is determined that it is immediately after the start of the accelerator-off, the basic deceleration index kdtmp set in step S120 is set as the deceleration index kd (step S310), and this routine is terminated. When it is determined that it is not immediately after the start of the accelerator-off, the previous deceleration index (previous kd) is set as the deceleration index kd (step S320), and this routine is terminated. Therefore, when the lost condition of the preceding vehicle continues to be satisfied from the start of the accelerator-off, the basic deceleration index kdtmp immediately after the start of the accelerator-off is held as the deceleration index kd. Also, when the lost condition of the preceding vehicle switches from not being satisfied to being satisfied during the continuation of the accelerator-off, the deceleration index kd immediately before the switch is held. As a result, when the preceding vehicle is lost, for example, when the preceding vehicle is lost on a curved road, when the preceding vehicle makes a left or right turn or changes lanes and is lost, when the preceding vehicle suddenly accelerates and is lost, etc., the deceleration index kd is held to suppress a sudden decrease in the target deceleration Dv*, suppress a sudden decrease in the deceleration of the vehicle, suppress giving a sense of discomfort to the driver, and give a relatively natural deceleration feeling.

[0049] FIG. 7 is a time chart showing an example of the states of the satisfaction or non-satisfaction of the lost condition, the approach feeling index kp, the basic deceleration index kdtmp, the deceleration index kd, and the target deceleration Dv* when the accelerator is off in the modified example and the second comparative example. In the figure, for the deceleration index kdtmp and the target deceleration Dv*, the solid line shows the state of the modified example, and the one-dot chain line shows the state of the second comparative example. In the second comparative example, the basic deceleration index kdtmp is set as the deceleration index kd without considering the satisfaction or non-satisfaction of the lost condition.

[0050] In the modified example and the second comparative example, when the lost condition is not satisfied when the accelerator is off (before time t2), the basic deceleration index kdtmp based on the approach feeling index kp is set as the deceleration index kd, and the target deceleration Dv* is set based on this deceleration index kd to control the motor 62. Thereby, the deceleration index kd and the target deceleration Dv* can be rapidly changed with respect to the changes in the approach feeling index kp and the basic deceleration index kdtmp based on the change in the inter-vehicle distance d from the preceding vehicle or the like, and the deceleration of the vehicle can be rapidly adjusted.

[0051] In the second comparative example, when the lost condition is satisfied (at time t2) during the continuation of the accelerator-off state, such as when the preceding vehicle no longer exists within a predetermined distance d1 ahead of the host vehicle, and the approach feeling index kp and thus the basic deceleration index kdtmp suddenly decrease, even in such a case, by setting the basic deceleration index kdtmp as the deceleration index kd, the deceleration index kd and the target deceleration Dv* will also suddenly decrease. For this reason, when the preceding vehicle is lost, the deceleration of the vehicle may suddenly decrease, which may give the driver a sense of discomfort. On the other hand, in the modified example, when the lost condition is satisfied (at time t2), when the approach feeling index kp and thus the basic deceleration index kdtmp suddenly decrease, by holding the deceleration index kd, it is possible to suppress the sudden decrease of the target deceleration Dv*. Thereby, when the preceding vehicle is lost, it is possible to suppress the sudden decrease of the deceleration of the vehicle, suppress giving the driver a sense of discomfort, and give a relatively natural deceleration feeling.

[0052] In the electronic control unit 50 mounted on the electric vehicle 20 of the modified example described above, when the accelerator is off, the approach index kp is set so that it increases as the inter-vehicle distance d from the preceding vehicle becomes shorter, and the basic deceleration index kdtmp is set so that it increases as the set approach index kp increases. Subsequently, when the lost condition is not satisfied, the basic deceleration index kdtmp is set as the deceleration index kd, and when the lost condition is satisfied, the deceleration index kd is held. Then, the target deceleration Dv* is set so that it increases as the deceleration index kd increases, and the motor 62 is controlled so that the vehicle decelerates at the target deceleration Dv*. In this way, when the lost condition is satisfied, by holding the deceleration index kd, when the preceding vehicle is lost, it is possible to suppress a sudden decrease in the deceleration of the vehicle, suppress giving a sense of discomfort to the driver, and give a relatively natural deceleration feeling.

[0053] In the electronic control unit 50 mounted on the electric vehicle 20 of this modified example, when the accelerator is off and the lost condition is not satisfied, it is assumed that the basic deceleration index kdtmp is set as the deceleration index kd. However, at this time, it may be configured to perform a smoothing process using a smoothing constant Ns (for example, value Ns1) on the basic deceleration index kdtmp to set the deceleration index kd. Also, at this time, it may be configured to perform a gradual change process other than the smoothing process, such as various filter processes or rate processes, on the basic deceleration index kdtmp to set the deceleration index kd.

[0054] In the electronic control unit 50 mounted on the electric vehicle 20 of the embodiment and the modified example described above, the approach index kp is calculated by the above formula (1) using the inter-vehicle distance d, the vehicle speed Vs, and the relative vehicle speed Vr. However, it may be configured to calculate the approach index kp using the inter-vehicle distance d and the vehicle speed Vs without considering the relative vehicle speed Vr. Also, it may be configured to calculate the approach index kp using the inter-vehicle distance d and the relative vehicle speed Vr without considering the vehicle speed Vs. Furthermore, it may be configured to calculate the approach index kp using only the inter-vehicle distance d without considering the vehicle speed Vs and the relative vehicle speed Vr.

[0055] In the electronic control unit 50 mounted on the electric vehicle 20 of the embodiment and the above-described modified example, the approach index kp is calculated based on the inter-vehicle distance d and the like, and the basic deceleration index kdtmp is set based on the calculated approach index kp. However, the basic deceleration index kdtmp may be directly set based on the inter-vehicle distance d and the like.

[0056] In the electronic control unit 50 mounted on the electric vehicle 20 of the embodiment and the above-described modified example, the inter-vehicle distance d is compared with a predetermined distance d1, and the inter-vehicle distance increase rate Δd is compared with a threshold value Δdref, thereby determining whether or not the lost condition of the preceding vehicle is satisfied. However, without considering the inter-vehicle distance d, it may be determined whether or not the lost condition of the preceding vehicle is satisfied by comparing the inter-vehicle distance increase rate Δd with the threshold value Δdref. Further, without considering the inter-vehicle distance increase rate Δd, it may be determined whether or not the lost condition of the preceding vehicle is satisfied by comparing the inter-vehicle distance d with the predetermined distance d1. Furthermore, instead of comparing the inter-vehicle distance d with the predetermined distance d1, it may be configured to check the value of the preceding vehicle flag Fv indicating whether or not a preceding vehicle exists within a predetermined distance d1 ahead of the host vehicle.

[0057] In the electronic control unit 50 mounted on the electric vehicle 20 of the embodiment and the above-described modified example, the target deceleration Dv* is set using the vehicle speed Vs and the deceleration index kd. However, the target deceleration Dv* may be set using only the deceleration index kd without considering the vehicle speed Vs.

[0058] In the embodiment, the electronic control unit 50 as an in-vehicle control device mounted on the electric vehicle 20 equipped with the driving motor 62 and the battery 40 has been described. However, it may be in the form of an in-vehicle control device mounted on a hybrid vehicle equipped with an engine in addition to the driving motor and the battery, or in the form of an in-vehicle control device mounted on a fuel cell vehicle equipped with a fuel cell in addition to the driving motor and the battery. In these cases, when the target deceleration Dv* is set at the time of accelerator-off, for example, similar to the case of the electric vehicle 20, it is conceivable to control the motor so that the vehicle decelerates at the target deceleration Dv* by the braking force from the motor. Further, it may be in the form of an in-vehicle control device mounted on an engine vehicle equipped with an engine without a driving motor, specifically, an engine vehicle that transmits the power from the engine to the drive wheels via a stepped transmission or a continuously variable transmission and runs. In this case, when the target deceleration Dv* is set at the time of accelerator-off, for example, it is conceivable to control the gear stage of the stepped transmission or the gear ratio of the continuously variable transmission so that the vehicle decelerates at the target deceleration Dv* by the braking force due to engine braking.

[0059] Note that the correspondence relationship between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems is an example for specifically explaining the form for implementing the invention described in the column of means for solving the problems in the embodiment. Therefore, it does not limit the elements of the invention described in the column of means for solving the problems. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description in that column, and the embodiment is merely a specific example of the invention described in the column of means for solving the problems.

[0060] As described above, the embodiments have been used to explain the forms for implementing the present invention. However, the present invention is not limited to such embodiments, and it goes without saying that the present invention can be implemented in various forms without departing from the gist of the present invention.

Industrial Applicability

[0061] The present invention can be used in the manufacturing industry of in-vehicle control devices and the like.

Description of Symbols

[0062] 20 Electric vehicle, 22 Ignition switch, 24 GPS, 26 In-vehicle camera, 28 Millimeter-wave radar, 30 Vehicle speed sensor, 32 Acceleration sensor, 34 Accelerator sensor, 36 Brake sensor, 38 Battery actuator, 40 Battery, 50 Electronic control unit, 51 CPU, 52 ROM, 53 RAM, 54 Flash memory, 60 Drive actuator, 62 Motor, 64 Brake actuator, 66 Brake device, 68 Display device, 70 Meter, 80 Navigation system, 82 Map information database, 84 Display unit.

Claims

1. An in-vehicle control device mounted on a vehicle and performing deceleration control of the vehicle when the accelerator is off, when the accelerator is off, a basic deceleration index as a basic value of a deceleration index used for setting a target deceleration is set such that it increases as the inter-vehicle distance from the preceding vehicle becomes shorter and rapidly decreases at the time of switching from non-establishment to establishment of the lost condition of the preceding vehicle compared to the time of continuous non-establishment and continuous establishment, the basic deceleration index is subjected to a creep process that moderates the change in the deceleration index when the lost condition is established compared to when the lost condition is not established, and the deceleration index is set, the target deceleration is set such that it increases as the deceleration index increases, and the deceleration control is executed so that the vehicle decelerates at the target deceleration, in-vehicle control device.

2. The in-vehicle control device according to claim 1, the basic deceleration index is subjected to a smoothing process using a smoothing constant that increases when the lost condition is established compared to when the lost condition is not established as the creep process, and the deceleration index is set, in-vehicle control device.

3. An in-vehicle control device mounted on a vehicle and performing deceleration control of the vehicle when the accelerator is off, when the accelerator is off, a basic deceleration index as a basic value of a deceleration index used for setting a target deceleration is set such that it increases as the inter-vehicle distance from the preceding vehicle becomes shorter and rapidly decreases at the time of switching from non-establishment to establishment of the lost condition of the preceding vehicle compared to the time of continuous non-establishment and continuous establishment, when the lost condition is not established, the basic deceleration index is set as the deceleration index, and when the lost condition is established, the deceleration index is held, the target deceleration is set such that it increases as the deceleration index increases, and the deceleration control is executed so that the vehicle decelerates at the target deceleration, in-vehicle control device.

4. The in-vehicle control device according to any one of claims 1 to 3, the lost condition includes at least one of a condition that the preceding vehicle does not exist within a predetermined distance and a condition that an increase amount per unit time of the inter-vehicle distance from the preceding vehicle is equal to or more than a predetermined increase amount, in-vehicle control device.

5. The in-vehicle control device according to any one of claims 1 to 4, The basic deceleration index is set such that the shorter the inter-vehicle distance from the preceding vehicle, the higher the index; the higher the vehicle speed of the vehicle, the higher the index; and the higher the relative vehicle speed of the vehicle with respect to the vehicle speed of the preceding vehicle, the higher the index. In-vehicle control device. **Claim 6** An in-vehicle control device according to any one of Claims 1 to 5, The target deceleration is set such that the higher the deceleration index, the higher the target deceleration; and the higher the vehicle speed of the vehicle, the higher the target deceleration. In-vehicle control device.

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