JP4151480B2 - Automatic deceleration control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of automatic deceleration control devices.
[0002]
[Prior art]
As this type of conventional technology, the vehicle being driven decelerates by automatically performing braking control based on sensing of vehicle behavior, such as exceeding a certain lateral G during turning motion, curves, etc. Thus, a device for suppressing deviation from the route on which the vehicle travels has been devised. These estimate the route on which the vehicle travels based on the steering angle, etc., and suppress the overspeed state that impairs the stability of the vehicle, thereby making it easier to maintain the travel route.
[0003]
In addition, the vehicle recognizes the state of the curve before entering the vehicle using a navigation system or a sensor such as a camera, and if the traveling vehicle speed is larger than the curve, the automatic deceleration control is performed without waiting for the curve to arrive. An apparatus has also been devised (see, for example, Patent Document 1).
[0004]
[Patent Document 1]
JP 2000-127798 A
[0005]
[Problems to be solved by the invention]
However, in such a conventional automatic deceleration control device, when performing deceleration control that automatically decelerates on the basis of the stability of the vehicle behavior during turning, it is necessary to perform switching operations such as S-shaped and crank. When traveling along a route or traveling along a curve with a low curvature radius at a low speed, there may be a situation where steering for traveling along the target route cannot catch up. At this time, there is a problem that the vehicle deviates from the target route even if the stability of the vehicle behavior is not impaired.
[0006]
The present invention has been made paying attention to the above problems, and an object of the present invention is to provide an automatic deceleration control device capable of suppressing the vehicle from deviating from the target route in a situation where switching and operation are required. There is to do.
[0007]
[Means for Solving the Problems]
  In order to achieve the above object, in the automatic deceleration control device of the present invention, vehicle speed detection means for detecting the vehicle speed of the host vehicle, road information detection means for detecting road information ahead of the host vehicle,The vehicle speed andBased on the road informationNecessary for traveling a predetermined distance in front of the host vehicleSteering speedRequired steering speed isEstimatenecessarySteering speed estimation means, andnecessaryDetermining means for determining whether or not the steering speed is greater than a preset allowable steering speed;A necessary steering amount estimating means for estimating a necessary steering amount that is a steering amount necessary to pass the predetermined distance;SaidBy dividing the required steering amount by the required steering speed to calculate the passage time of the predetermined distance, and dividing the predetermined distance by the passage time.A target vehicle speed setting means for setting a target vehicle speed, and the determination means;necessaryAnd an automatic deceleration control means for controlling a braking force so that the vehicle speed becomes the target vehicle speed when it is determined that the steering speed is higher than the allowable steering speed.
[0008]
【The invention's effect】
  In the automatic deceleration control device of the present invention,If it is determined that the steering speed is greater than the allowable steering speed, the braking force is controlled so that the vehicle speed becomes the target vehicle speed.It is possible to suppress the vehicle from deviating from the target route in a situation where switching and an operation are required.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0023]
  (First embodiment)
  Figure1These are the schematic block diagrams of the automatic deceleration control apparatus of 1st Example. This vehicle is a rear wheel drive vehicle equipped with an automatic transmission and a conventional differential gear, and the braking device is configured to be able to independently control the braking force of the left and right wheels for both the front and rear wheels.
[0024]
In the figure, 1 is a brake pedal, 2 is a booster, 3 is a master cylinder, 4 is a reservoir, 5FL, 5FR, 5RL and 5RR are a left front wheel, a right front wheel, a left rear wheel and a right rear wheel, respectively. 6FL, 6FR , 6RL and 6RR are brake discs for the left front wheel 5FL, right front wheel 5FR, left rear wheel 5RL and right rear wheel 5RR, respectively. 7FL, 7FR, 7RL and 7RR are the left front wheel 5FL, right front wheel 5FR and left rear wheel, respectively. This is a wheel cylinder of the wheel 5RL and the right rear wheel 5RR.
[0025]
The wheel cylinders 7FL to 7RR are configured to frictionally clamp the corresponding brake discs 6FL to 6RR by supplying hydraulic pressure to apply a braking force (braking force) to each wheel.
[0026]
A braking fluid pressure control unit 8 is interposed between the master cylinder 3 and the wheel cylinders 7FL to 7RR. The braking fluid pressure boosted by the master cylinder 3 according to the depression amount of the brake pedal 1 by the driver is supplied to the wheel cylinders 7FL to 7RR of the wheels 5FL to 5RR. The brake fluid pressure control unit 8 individually controls the brake fluid pressures of the wheel cylinders 7FL to 7RR. The braking fluid pressure control unit 8 is configured to include an actuator for each of the front, rear, left and right hydraulic pressure supply systems (each channel). Thereby, each wheel is braked individually. Here, the actuator is configured using a proportional solenoid valve so that the hydraulic pressure of each of the wheel cylinders 7FL to 7RR can be controlled to an arbitrary braking hydraulic pressure, for example.
[0027]
The braking fluid pressure control unit 8 is configured using a braking fluid pressure control unit used for anti-skid control and traction control. Specifically, the brake fluid pressure control unit 8 increases the brake fluid pressure as in the driving force control device (TCS), reduces the brake fluid pressure as in the anti-skid control device (ABS), or the vehicle. The brake fluid pressure of each wheel can be adjusted independently as in a dynamics control controller (VDC).
[0028]
Such a brake fluid pressure control unit 8 controls the brake fluid pressures of the wheel cylinders 7FL to 7RR based on a brake fluid pressure command value from a braking / driving force control unit 9 described later.
[0029]
The vehicle also includes a drive torque control unit 11 for controlling the drive torque. The drive torque control unit 11 controls the operating state of the engine 10 and the selected transmission gear ratio of the automatic transmission 12, and controls the throttle opening of the throttle valve 14 via the throttle controller 13. The drive torque to a certain rear wheel 5RL, 5RR is controlled. Here, the operation state control of the engine 10 is performed, for example, by controlling the fuel injection amount and the ignition timing, and simultaneously controlling the throttle opening.
[0030]
The drive torque control unit 11 is also configured to control the drive wheel torque while referring to the drive torque command value when the drive torque command value is input from the braking / driving force control unit 9 described above. . The drive torque control unit 11 outputs the drive torque Tw on the wheel axle to the braking / driving force control unit 9.
[0031]
The driving torque control unit 11 and the braking fluid pressure control unit 8 are for controlling the running state of the vehicle, that is, as a result, the vehicle is driven by adjusting the acceleration / deceleration, the longitudinal speed, etc. of the own vehicle. The state is controlled. The brake fluid pressure control unit 8 and the drive torque control unit 11 can be operated independently, but the overall function is controlled by the braking / driving force control unit 9.
[0032]
The vehicle also includes an acceleration sensor 17 that detects longitudinal acceleration Xg and lateral acceleration Yg generated in the host vehicle, a yaw rate sensor 18 that detects yaw rate φ generated in the host vehicle, an output pressure of the master cylinder 3, so-called master cylinder. A master cylinder pressure sensor 19 that detects the hydraulic pressure Pm, a throttle opening sensor 20 that detects the throttle opening A, and a steering angle sensor that detects the steering angle δ of the steering wheel 21 (where δ is converted to an angle at the wheel). 22 and wheel speed sensors 23FL to 23RR for detecting the rotational speeds of the wheels 5FL to 5RR, that is, the wheel speed Vwi (i = 1, 2, 3, 4). Where Vw₁Is the wheel speed of the front left wheel 5FL, Vw₂Is the wheel speed of the front right wheel FR, Vw₃Is the wheel speed of the left rear wheel RL, Vw₄Is the wheel speed of the right rear wheel RR. Each of these sensors outputs a detection signal to the braking / driving force control unit 9.
[0033]
Further, the vehicle is provided with a selection switch 24 for the allowable operation difficulty level on the steering wheel 21. The selection switch 24 is a switch for the driver to set an allowable steering speed during turning, and the set allowable steering speed Δδ_select is input to the braking / driving force control unit 9.
[0034]
The vehicle also includes a navigation device 25. The navigation device 25 is configured to detect the host vehicle position using GPS (Global Positioning System). The navigation device 25 includes a nationwide map information device 25a and a travel route information device 25b. The nationwide map information device 25a is configured to provide information on the traveling road ahead of which the vehicle is traveling, shape information on the traveling road (for example, radius of the curved road), topographic information such as the gradient of the traveling road, and environmental information such as intersections and tunnels. Holding. The national map information device 25a holds node point information indicating the coordinates of the node points set on the traveling road. Here, the node point indicates a point on a travel route on which the vehicle can travel, that is, the node row indicates a straight or curved travel route on which the vehicle travels. In addition, information such as road width, road type, intersection, tunnel, entry prohibited road, and the like is added to the node point information. The travel path information device 25b detects information on the travel path environment by communicating information with infrastructure (hereinafter referred to as infrastructure) equipment installed on a so-called road.
[0035]
This navigation device 25 retrieves node point information (forward road information) indicating the coordinates of the node points (a plurality of node points if there are a plurality of points) of the travel road from the information held by the nationwide map information device 25a. Then, the node point information is output to the braking / driving force control unit 9 together with the own vehicle position information.
[0036]
The vehicle also includes a display unit 26 for displaying an alarm and a speaker 27 for outputting an alarm sound by sound or buzzer sound. The display unit 26 and the speaker 27 are provided, for example, on the panel unit of the driver's seat. And the display part 26 and the speaker 27 are comprised so that it may drive with the control signal from the braking / driving force control unit 9, for example. In this embodiment, the display unit 26 and the speaker 27 are driven when a forward curve is detected so that automatic deceleration control is activated.
[0037]
If the detected vehicle traveling state data has left and right directionality, the left direction is the positive direction and the right direction is the negative direction. For example, the yaw rate φ ′, the lateral acceleration Yg, the steering angle δ, and the yaw angle φ are positive values when turning left and negative values when turning right. Further, the lateral displacement X becomes a positive value when shifted to the left from the center of the traveling lane, and becomes a negative value when shifted to the right.
[0038]
As described above, the braking / driving force control unit 9 is configured to receive information from each component such as a sensor and perform various processes based on the information. In this embodiment, a braking control process that is one of such processes performed by the braking / driving force control unit 9 will be described.
[0039]
  Next, the operation will be described.
  [Brake control processing]
  Figure2These are flowcharts which show the flow of the braking control process performed by the braking / driving force control unit 9. This process is performed at regular intervals at regular intervals in an operating system (not shown).
[0040]
First, in step S101, various data from the sensors and the drive torque control unit 11 are read. From the sensors, longitudinal acceleration Xg, lateral acceleration Yg, yaw rate φ, each wheel speed Vwi (i = 1 to 4), accelerator opening Acc, master cylinder hydraulic pressure Pm, steering angle δ, and further drive torque Tw are read.
[0041]
In the subsequent step S102, the vehicle speed V is calculated. In this embodiment, during normal travel, the vehicle speed V is calculated from the wheel speeds of the respective wheels according to the following formula (1) as an average of the front wheel speeds. V = (VwFR + VwFL + VwRR + VwRL) / 4 ... (1)
Further, when the ABS control or the like is operating, the estimated vehicle speed estimated in the ABS control is used.
[0042]
In subsequent step S103, an allowable steering speed Δδcap is set as an allowable value of an operation state that can be easily operated by the driver in a normal situation. This allowable value depends on the characteristics of the steering device of the vehicle, for example, if the assist device is strong and the steering device can be operated with a small torque, the allowable value is set larger. Set. Further, when steering is performed by an automatic steering device or the like, the steering capability of the automatic steering device may be set.
[0043]
Instead of using the steering speed, the yaw rate change Δφcap may be used, and {(L × Δφcap) / V} may be used instead of the allowable steering speed Δδcap. However, L is a wheel base.
[0044]
In addition, a certain threshold value Trqcap may be set to the steering operation torque itself, and the coefficient Kt may be approximately multiplied to set as shown in the following equation (2).
Δδcap ＝ K × Trqcap… (2)
[0045]
  Further, the allowable steering speed Δδcap is determined according to the vehicle speed V.3By applying the correction coefficient Δδcap_vel_times as follows, the following equation (3) may be used.
  Δδcap = Δδcap × Δδcap_vel_times (3)
  Thereby, the sensitivity of the deceleration control with respect to the steering speed at the time of high speed becomes high. It should be noted that it may be set so that the sensitivity of the deceleration control becomes low during slow driving when performing a parking operation or the like.
[0046]
Here, when returning the steering wheel to the neutral position, it is assumed that the driver can return the steering earlier when returning to the neutral position, and another allowable steering speed Δδcap when returning to the neutral position is set to a large value, for example, 1.5 times. May be.
[0047]
In addition, even when an operation to return the steering wheel to the neutral position is expected, it is assumed that the driver can return the steering more quickly by returning to the neutral position, and another allowable steering speed Δδcap at the time of returning to the neutral position is, for example, 1.5 times You may set large.
[0048]
  For example, the figure4When turning back from left turn to right turn at an intersection having a shape like that shown in FIG.5As shown in FIG. 5, the portion c where the handle is returned to the neutral position is made about 1.5 times larger than the portions a and e which cut the handle left and right.
[0049]
In addition, with the switch provided in advance by the driver, for example, if there are three stages of high sensitivity, medium sensitivity, and low sensitivity, the high sensitivity is 0.8 times, the sensitivity is 1.0 times, and the low sensitivity is 1.5 times. The value of Δδcap may be corrected.
[0050]
In subsequent step S104, the steering speed | Δδ | is detected as the actual steering state of the vehicle. The value directly measured by the rudder angle sensor 22 may be used for | Δδ |, but instead, there may be a situation where the steering speed is not reflected in the vehicle behavior, such as when the road surface μ is low. | (L × Δφ) / V | may be used instead of the steering speed Δδ.
[0051]
In subsequent step S105, the current difficulty state of operation is detected by comparing the allowable steering speed Δδcap set in step S103 with the steering speed Δδ detected in step S104. Specifically, when | Δδ |> Δδcap, it is detected that the operation is difficult.
[0052]
  In step S106, a reference target vehicle speed Vo is set. For example, the figure6When traveling while turning right on a rotary road like that shown in the figure, when turning the handle largely to the left at the position a in the figure,7A case where the vehicle passes at a steering angle δ as shown in FIG. The steering speed Δδ at this time is8It is assumed that a speed pattern is drawn such that the steering speed Δδ exceeds the allowable steering speed Δδcap and reaches Δδex at a point a.
[0053]
The reference vehicle speed Vo at this time is calculated as follows.
First, a ratio ex_ratio where the steering speed Δδ exceeds the allowable steering speed Δδcap is obtained by the following equation (4).
ex_ratio = Δδ / Δδcap (4)
[0054]
  Figure8When Δδ is Δδex as shown above, ex_ratio is expressed by the following equation (5).
  ex_ratio = Δδex / Δδcap (5)
[0055]
  In addition, when ex_ratio is large, it is assumed that the difference from the drawn route is widened.9As described above, ex_ratio may be corrected by setting a correction coefficient ex_times set according to the value of ex_ratio as shown in the following equation (6).
  ex_ratio = ex_times × ex_ratio (6)
[0056]
Here, since the steering speed Δδ is proportional to the vehicle speed V when traveling on the same road shape, the target vehicle speed Vo with respect to the current vehicle speed V is obtained by the following equation (7).
Vo ＝ V / ex_ratio… (7)
Vo is corrected by ex_ratio calculated one by one.
[0057]
In addition, instead of calculating the target vehicle speed Vo one by one, once the target vehicle speed Vo that prompts deceleration is calculated, the rate of increase in Vo per hour unless the target vehicle speed Vo of a small value that prompts further deceleration is updated You may make it limit. In this case, when the steering wheel is returned to near neutral and the difficulty of operation is resolved, the limit of the rate of increase of the target vehicle speed Vo is canceled, or the limit is canceled after a predetermined time set as a time limit device has elapsed. To do.
[0058]
As a result, even if the operation difficulty state condition | Δδ |> Δδcap is canceled, the deceleration control continues for a while, and the effect of the deceleration control can be obtained even if the operation difficulty state occurs only for a moment.
[0059]
Thereby, the target deceleration is set as in the following equation (8).
Xgs = (V²-Vo²) / (2 * Ln) (8)
Here, Xgs ≦ Xgs_max_value (predetermined value) is set, and the limit is set so that the value of Xgs does not become too large.
[0060]
Ln is a predetermined distance defined in advance, but a value corresponding to a predetermined time Tln (for example, 0.5 seconds) with respect to the current vehicle speed V may be given one by one using the following equation (9).
Ln = V × Tln (9)
[0061]
Also, let Ln be as close to 0 as possible (V²-Vo²Xgs may have a value of Xgs_max_value while the condition of >> 0 is satisfied by the rate of increase limiter of the target vehicle speed Vo or a timing device.
[0062]
In a succeeding step S107, an estimated road surface μ value is calculated. In this embodiment, the road surface μ is calculated from the following equation (10) from the relationship between the braking / driving force acting on each wheel and the slip generated on each wheel.
Kμ = g (braking / driving force of each wheel, slip ratio of each wheel) (10)
[0063]
In this embodiment, one of the methods for estimating the road surface μ from the state of the wheel is used. However, it is not necessary to limit to this method, and when the infrastructure is installed, as the curve information from the infrastructure before the curve, Road surface μ information may be obtained.
[0064]
Thereby, the deceleration Xgs calculated in the previous step S106 is reflected as shown in the following equation (11).
Xgs = Xgs × Kμ (11)
Further, Xgs is corrected downward when the gradient angle is upward, and Xgs is corrected upward when it is downward.
[0065]
In step S108, a target pressure reduction is calculated. In the present embodiment, when the control start determination is made, first, the control target hydraulic pressure Pc is calculated from the target deceleration Xgs calculated up to step S107 according to the following equation (12), and thereafter, by the driver. The target brake hydraulic pressure Psi of each wheel is calculated in consideration of the master cylinder hydraulic pressure Pm that is a braking operation.
Pc = Kb * Xgs (12)
Here, Kb is a constant determined from brake specifications and the like.
[0066]
Also,
Psfr = max (Pm, Pc)… (13)
Psrr = h (Psfr)… (14)
Here, Psfr is the front-wheel target braking hydraulic pressure, and Psrr is the rear-wheel target braking hydraulic pressure, which is a select high between the target hydraulic pressure by control and the hydraulic pressure by driver braking. The function h () is a function for calculating the rear wheel hydraulic pressure from the front wheel pressure so as to achieve an optimal front / rear braking force distribution.
[0067]
In the subsequent step S109, the driving force of the driving wheel is calculated. In the present embodiment, when the automatic deceleration control is being performed and the steering speed is increased, the engine output is reduced to prevent acceleration even if the accelerator operation is performed. In other cases, the engine output is controlled in accordance with the driver's accelerator operation. That is, during operation, the target drive torque Trqds is calculated according to the accelerator opening Acc and the control amount of the automatic deceleration control, and during non-operation, the target drive torque Trqds is calculated according to the accelerator opening Acc.
[0068]
1) When the control operation flag flg_gensoku = ON, the target drive torque Trqds is obtained from the following equation (15).
Trqds = f (Acc)-g (Pc) (15)
[0069]
2) When the control operation flag flg_gensoku = OFF, the target drive torque Trqds is obtained from the following equation (16).
Trqds = f (Acc) (16)
[0070]
Here, f (Acc) is a function for calculating the target drive torque according to the accelerator opening. Further, g (Pc) is a function for calculating a braking torque expected to be generated by the braking fluid pressure. According to the above formulas (15) and (16), during automatic deceleration control, the braking torque generated by the control is subtracted to generate drive torque.
[0071]
In the subsequent step S110, a drive signal is output to the brake fluid pressure control unit 8 and the drive torque control unit 11 in accordance with the target brake fluid pressure Psi and the target drive torque Trqds. At this time, the operation may be warned to the driver by the display unit 26 or the speaker 27.
[0072]
  That is, in the automatic deceleration control device of the first embodiment, the driver's steering speed Δcap and the allowable steering speed Δδcap are compared, and if | Δcap |> Δδcap, | Δcap | ≦ Δδcap. Since the target brake hydraulic pressure Psi and the target drive torque Trqds are set to the vehicle, it is possible to suppress the vehicle from deviating from the target route.The
[0073]
  Moreover, since the allowable steering speed Δδcap is set as the allowable value of the operation state that can be easily operated by the driver, deviation from the target route can be prevented more reliably.The
[0074]
  In addition, if {(L × Δφcap) / V} is used instead of the allowable steering speed Δδcap using the yaw rate change Δφcap as the allowable value of the operation state that can be easily operated by the driver, the vehicle slips. When counter-steer is applied in an easy-to-understand situation, it is possible to avoid deviation from the target route while avoiding inadvertent deceleration.The
[0075]
  Further, since the allowable steering speed Δδcap is corrected by the correction coefficient Δδcap_vel_times according to the vehicle speed V, the sensitivity of the deceleration control with respect to the steering speed during high-speed traveling is increased. Therefore, deviation from the target route during high-speed driving can be prevented.The
[0076]
  (Second embodiment)
  The configuration of the second embodiment is shown in FIG.1Since it is the same as the structure of the automatic deceleration control device of the first embodiment shown in FIG.
[0077]
  Next, the operation will be described.
  [Brake control processing]
  Figure10These are flowcharts which show the flow of the braking control process performed by the braking / driving force control unit 9. This process is performed at regular intervals at regular intervals in an operating system (not shown).
[0078]
First, in step S201, in addition to the information read in step S101, the position (X, Y) of the host vehicle by the navigation system and road information ahead of the host vehicle are read as data nodes (Xn, Yn, Ln). Here, Xn and Yn represent position information, and Ln represents a distance from the host vehicle position. In this embodiment, navigation is used as the forward curve detection means, but road-to-vehicle communication means that detects similar curve information by communication from an infrastructure facility installed in front of the curve may be used.
[0079]
In subsequent step S202, the vehicle speed V is calculated in the same manner as in step S102.
[0080]
In subsequent step S203, the turning radius of each node point indicating the route on which the host vehicle can travel is calculated based on the node sequence indicating the route ahead of the host vehicle read in step 201. In this embodiment, the turning radius of each node point is calculated from the coordinates of each node point read in step S201. Several methods can be considered for calculating the turning radius itself. As shown in the following formula (17), the turning radius is calculated from the coordinates of three consecutive points. (The calculated turning radius is Rn)
Rn = f (Xn-1, Yn-1, Xn, Yn, Xn + 1, Yn + 1) (17)
Here, f () is a function for calculating the turning radius from the coordinates of three points. At this time, the turning radius is calculated with a sign, and the left turn is positive and the right turn is negative.
[0081]
In the present embodiment, a method of calculating the turning method from the coordinates of the three points has been shown, but other methods such as a method of calculating the turning radius using an angle formed by a straight line connecting the preceding and following node points can be considered. In this embodiment, the turning radius is calculated based on the coordinates of each node point. However, the turning radius of each node point is stored as node information in the map data, and the value is searched. May be. Also, the turning radius R of the vehicle position is calculated in the same manner.
[0082]
In subsequent step S204, a control target route is selected. When there is a branch on the route, control the specified route if the route to travel in advance has been specified, and control the direction where the turn R in the curve is large, that is, the curve is not tight, if not specified Set as the target route.
[0083]
  In subsequent step S205, the control target point (section) is calculated. In this embodiment, the target node point to be controlled from among the node points ahead of the host vehicle.ofThe change amount ΔR of the turning radius R is converted into a value of | Δδfuture | from the following equation (18), and the value of | Δδfuture |bigControl the intervalTargetTreat as interval.
  ΔR = L / | Δδfuture | (18)
  However, L is a wheel base.
[0084]
When the control target section is detected, the arrival time TLn to the control target section is obtained from the following equation (19) based on the relationship between the distance Ln between the host vehicle and the control target section and the host vehicle speed V.
TLn = Ln ÷ V (19)
[0085]
At this time, if TLn is too large, the operation starts at a position far from the intersection and a sense of incongruity occurs. Therefore, the limit value TLnlimit is set to, for example, 5 seconds in advance so that TLn does not have a certain size or more. On the other hand, the limit is set so that TLn does not become too small.
[0086]
  In subsequent step S206, an allowable steering speed Δδcap is set as an allowable value of an operation state that can be easily operated by the driver in a normal situation. At this time, the allowable steering speed Δδcap depends on the road width detected by the navigation system.11By applying the correction coefficient Δδcap_width_times as described above, the following equation (20) is calculated.
  Δδcap = Δδcap × Δδcap_width_times (20)
[0087]
This increases sensitivity in situations where the road is wide and usually runs out-in-out and the steering speed is kept low, so it is possible to detect situations that are likely to deviate from the route you want to travel early. .
[0088]
In the subsequent step S207, the steering speed Δδpre required to pass through the road R change ΔR_taishoukukan during the section length ΔX in the control target section detected in step S205 is estimated.
[0089]
The time T_tuuka required when passing ΔX at the vehicle speed V is expressed by the following formula (21), and the amount of change in the road R per unit time is expressed by the following formula (22).
T_tuuka = ΔX / V (21)
ΔR / T_tuuka (22)
[0090]
Therefore, the estimated steering speed Δδpre per unit time can be obtained by the following equation (23).
Δδpre = L / (ΔR / T_tuuka) (23)
[0091]
In the subsequent step S208, the allowable steering speed Δδcap set in step S206 is compared with the required steering speed Δδpre estimated in step S207, and it is detected that the operation difficulty state is satisfied when Δδcap <Δδpre.
[0092]
The detection of the operation difficulty state in step S207 and step S208 may be determined based on the condition of allowable passing vehicle speed <current vehicle speed by looking at the relationship between the allowable passing vehicle speed and the current vehicle speed V. The method for obtaining the allowable passing vehicle speed will be described in the next step.
[0093]
In subsequent step S209, a reference target vehicle speed Vo is calculated. The reference target vehicle speed Vo is equivalent to the allowable passing speed Vcap obtained from the allowable steering speed Δδcap.
The allowable passing speed Vcap is obtained as follows.
[0094]
First, from the road R: R1 at the start point of the section to be controlled or an arbitrary distance section Xi and the road R: R2 at the end point, the steering amount δsteer required to pass through the section is δ = L / R (L is Since it is a wheel base), it is expressed as the following formula (24).
δsteer = δ2-δ1 = L / R2-L / R1 (24)
[0095]
Here, since the allowable steering amount per unit time in the distance Xi is Δδcap, the time δtime required to steer δsteer when passing through the section of the distance Xi is obtained from the following equation (25). It is done.
δtime = δsteer / Δδcap (25)
As a result, the allowable passing speed Vcap is Xi / δtime.
[0096]
  In the following step S210, the road surface μ estimated value is displayed.2The calculation is performed in the same manner as in step S107. However, the deceleration is determined by Xgs described in the next step.
[0097]
In subsequent step S211, a target deceleration is calculated. In the present embodiment, first, from the vehicle speed V, the target vehicle speed Vo, and the distance Ln from the current position to the target node point (the intermediate node in the target section or the node closest to the host vehicle) obtained above, Calculate the target deceleration Xgs according to 26). It should be noted that the target node point may be used as the entrance of the curve as the vehicle is decelerated before the curve.
Xgs = (V²-Vo²) / (2 * Ln)
= (V²-Yglmit * | Rn |) / (2 * Ln) (26)
Here, the target deceleration Xgs is positive on the deceleration side.
[0098]
This target deceleration Xgs increases as the distance Ln between the control target point and the host vehicle decreases, and represents the deceleration required to reach the reference target vehicle speed Vo at that time at that time. Automatic deceleration control is started when a certain threshold value Xgs_start is reached.
[0099]
In the subsequent step S212, an alarm activation start determination is performed. In the present embodiment, the alarm activation start determination is performed according to the following equations (27) and (28) according to the target deceleration Xgs calculated in step S111.
1) When alarm is not activated (flg_warn = OFF)
Xgs ≧ Xgwarn… (27)
2) When the alarm is activated (flg_warn = ON)
Xgs ≧ Xgswarn−Khwarn… (28)
[0100]
Here, flg_warn is a flag indicating an alarm operating state, and the expression (27) or the expression (28) is turned on when established, and turned off when both expressions are not established. Khwarn is hysteresis for preventing hunting of alarm ON / OFF, and is set to a fixed value such as 0.03 g, for example. Further, Xgswarn is an alarm start determination setting value, and in this embodiment, it is assumed to be linked to the control start determination setting value Xgs_start as shown in the following equation (29).
Xgswarn ＝ Xgs_start × 0.7… (29)
[0101]
In the following step S213, a control operation start determination is performed. In this embodiment, the control operation start determination is performed according to the following equations (30) and (31) according to the target deceleration Xgs calculated in step S211 and the control start determination set value Xgs_start calculated in step S112. .
1) When control is not activated (flg_gensou = OFF)
Xgs ≧ Xgs_start… (30)
2) During control operation (flg_gensoku = ON)
Xgs ≧ Xgs_start−Kh… (31)
[0102]
Here, flg_gensoku is a flag indicating the operating state of control, and equation (30) or equation (31) is turned on when established, and both are turned off when not established. Kh is a hysteresis for preventing hunting of control ON / OFF, and is a fixed value such as 0.05 g.
[0103]
In addition, since the alarm and control operation start determination is corrected in conjunction with each other, the alarm always starts from the alarm and the control continues.
[0104]
The alarm start judgment setting value Xgswarn and the control start judgment setting value Xgs_start are based on the difference in speed depending on the environment around the driver. It may be changed.
[0105]
  In addition, the control start determination set value Xgs_start is set so that the operation timing is not too early in order to prevent a sense of incongruity due to a large deceleration from the front when entering a road that can be clearly recognized by the driver.12As shown in the figure, set a large value according to the road curvature.13As described above, the operation timing is delayed while ensuring the necessary deceleration amount.
[0106]
  Subsequent steps S214 to S216 are shown in FIG.2The same processing as in steps S108 to S110 is performed.
[0107]
Therefore, in the automatic transmission control device of the second embodiment, the steering speed Δδpre in the control target section is estimated and compared with the allowable steering speed Δδcap, and when Δδcap <Δδpre, the deceleration control is performed. Before falling into a situation where operation is difficult, it is possible to reliably prevent the vehicle from deviating from the target route by performing deceleration control.
[0108]
  Further, since the allowable steering speed Δδcap is corrected by the correction coefficient Δδcap_width_times corresponding to the road width detected by the navigation system, the sensitivity of the deceleration control is increased in a situation where the steering speed Δcap is kept low, and the target in accordance with the actual operation is increased. To prevent departure from the routeThe
[0109]
  Furthermore, when the curvature change of the road curvature path is large according to the curvature of the road R, the control start determination set value Xgs_start is delayed and the target deceleration Xgs is increased, so that the control start timing is not too early. This prevents the driver from feeling uncomfortable and prevents deviation from the target route.The
[0110]
  (Third embodiment)
  The configuration of the third embodiment is shown in FIG.1Since it is the same as the structure of the automatic deceleration control device of the first embodiment shown in FIG.
[0111]
  Next, the operation will be described.
  [Brake control processing]
  Figure14These are flowcharts which show the flow of the braking control process performed by the braking / driving force control unit 9. This process is performed at regular intervals at regular intervals in an operating system (not shown).
[0112]
  Steps S301 to S307 are shown in FIG.10Steps S201 to S207 are the same. Step S308 is2This is the same as step S104.
[0113]
In step S309, a comparison is made between the steering speed Δδpre estimated in step S307 and the actual steering speed Δcap detected in step S308. It should be noted that as the difference amount increases in accordance with the difference amount, the levels may be divided into “unusual state 1”, “unusual state 2”, and “unusual state 3”.
[0114]
Further, the threshold value of the difference amount between the estimated steering speed Δδpre and the actual steering speed Δδcap when detecting the abnormal state may be set so as to decrease as the vehicle speed increases.
[0115]
In step S310, when it is detected in step S309 that the vehicle is in an extremely normal state, the sensitivity is determined by correcting the allowable steering speed Δδcap set in step S306 to be a smaller criterion for determining the steering difficulty level in subsequent step S311. To improve. When the abnormal state is detected by dividing into levels in the previous step S309, correction is performed so that Δδcap decreases as the level of the abnormal state increases. Note that Δδcap in the non-normal state is returned to the original setting when the control for one control section is finished and the deceleration control is once finished.
[0116]
Steps S310 to S316 are the same as steps S105 to S110.
[0117]
That is, in the automatic deceleration control device of the third embodiment, when an abnormal operation is detected, the sensitivity is improved by correcting the allowable steering speed Δδcap to be small, and the sensitivity of the deceleration control is improved. The avoidance in the case of performing an obstacle avoidance operation while traveling along the route is improved, and a state of deviating from the target route can be prevented.
[0118]
(Other examples)
As mentioned above, although the automatic deceleration control apparatus of this invention has been demonstrated based on the 1st-3rd Example, about a specific structure, it is not restricted to these 1st-3rd Example, Claims Modifications and additions of the design are permitted without departing from the spirit of the invention according to the claims.
[Brief description of the drawings]
[Figure1FIG. 1 is a schematic configuration diagram of an automatic deceleration control apparatus according to a first embodiment.
[Figure2It is a flowchart showing the flow of a braking control process executed by the braking / driving force control unit of the first embodiment.
[Figure3FIG. 10 is a diagram showing an example of setting a correction coefficient for an allowable steering speed according to the vehicle speed.
[Figure4It is a diagram showing a traveling route of an intersection that needs to be turned back.
[Figure5FIG. 10 is a diagram showing an example of setting an allowable steering speed when traveling at an intersection that requires turning back.
[Figure6It is a diagram showing a travel route of a rotary road.
[Figure7It is a diagram showing a steering angle when traveling on a rotary road.
[Figure8It is a diagram showing an example of the steering speed when traveling on a rotary road.
[Figure9FIG. 10 is a diagram showing an example of correction of an excess ratio of the steering speed with respect to the allowable steering speed.
[Figure10It is a flowchart showing the flow of a braking control process executed by the braking / driving force control unit of the second embodiment.
[Figure11It is a diagram showing an example of allowable steering speed correction according to the road width.
[Figure12It is a diagram showing an example of deceleration correction according to road curvature.
[Figure13FIG. 10 is a diagram showing a delay in braking control operation timing due to allowable deceleration correction.
[Figure14It is a flowchart showing the flow of a braking control process executed by the braking / driving force control unit of the third embodiment.
[Explanation of symbols]
1 Brake pedal
2 Booster
3 Master cylinder
4 Reservoir
5FL left front wheel
5FR right front wheel
5RL left rear wheel
5RR Right rear wheel
6FL Left front wheel brake disc
6FR Brake disc for right front wheel
6RL Left rear wheel brake disc
6RR right rear wheel brake disc
7FL left front wheel wheel cylinder
7FR Right front wheel wheel cylinder
7RL Left rear wheel wheel cylinder
7RR Right rear wheel wheel cylinder
8 Braking fluid pressure control unit
9 Braking / driving force control unit
10 engine
11 Drive torque control unit
12 Automatic transmission
13 Throttle control device
14 Throttle valve
17 Acceleration sensor
18 Yaw rate sensor
19 Master cylinder pressure sensor
20 Throttle opening sensor
21 Steering wheel
22 Steering angle sensor
23FL Front wheel speed sensor
23FR Right front wheel speed sensor
23RL Left rear wheel speed sensor
23RR Right rear wheel speed sensor
24 selection switch
25 Navigation device
25a National map information device
25b Travel route information device
26 Display section
27 Speaker

Claims (4)

Vehicle speed detection means for detecting the vehicle speed of the host vehicle;
Road information detecting means for detecting road information ahead of the host vehicle;
Necessary steering speed estimation means for estimating a required steering speed that is a steering speed required to travel a predetermined distance ahead of the host vehicle based on the vehicle speed and the road information;
Determining means for determining whether the required steering speed is greater than a preset allowable steering speed;
A necessary steering amount estimating means for estimating a necessary steering amount that is a steering amount necessary to pass the predetermined distance;
Target vehicle speed setting means for calculating a passing time of the predetermined distance by dividing the required steering amount by the required steering speed, and setting a target vehicle speed by dividing the predetermined distance by the passing time ;
Automatic deceleration control means for controlling braking force so that the vehicle speed becomes the target vehicle speed when the determination means determines that the required steering speed is greater than the allowable steering speed;
An automatic deceleration control device comprising: In the automatic deceleration control device according to claim 1 ,
The automatic steering control device, wherein the allowable steering speed is set based on the road width. In the automatic deceleration control device according to claim 1 or 2 ,
A curvature change detecting means for detecting a change in curvature of the path;
The automatic deceleration control device increases the deceleration control amount when a change in curvature of the path is large. In the automatic deceleration control device according to any one of claims 1 to 3 ,
The automatic deceleration control device, wherein the allowable steering speed is corrected based on the vehicle speed.

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