JP2011031846A - Speed controller for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speed controller for a vehicle for accomplishing deceleration control giving less sense of incongruity to a driver when passing a curve existing in front of the vehicle, using simplified road database. <P>SOLUTION: In the road database, a first position Px# as an end point position of the curve degree constant section Cr#, and a constant curve degree Rm# of the curve degree constant section Cr# are previously stored to define a curve degree constant section Cr# in a curve of a road. Based on a vehicle position Pvh, a reference curve degree constant section existing in a position nearest to a vehicle among the curve degree constant sections Cr# existing on a road where a vehicle ahead of a vehicle travels is determined. Based on actual vehicle speed Vxa, the first position Px# of the reference curve degree constant section Cr#, and the constant curve degree Rm# of the reference curve degree constant section Cr#, the curve deceleration control is performed so that a vehicle appropriately passes a curve even when acceleration/deceleration operation by a driver is not performed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle speed control device, and more particularly to a device that performs automatic deceleration (deceleration control) of a vehicle when the vehicle passes a curve in front of the vehicle on a running road.

  As shown in FIG. 8, on a general road, one curve is in order from a curve start point (curve entrance) to a curve end point (curve exit), an approach relaxation curve section, a constant bending degree section, and an exit. It consists of relaxation curve sections. The relaxation curve is composed of a clothoid curve, for example. The relaxation curve section is provided so that the driver can smoothly turn the steering wheel and then gradually turn it back without requiring the driver to operate the steering wheel suddenly. It is for doing so.

  Conventionally, there is one described in Patent Document 1 as one of the speed control devices described above. In the apparatus described in Patent Document 1, in order to set the vehicle speed to an appropriate vehicle speed when the vehicle enters the curve, a deceleration distance that requires deceleration when entering the curve, and the current position of the vehicle to the curve start point. The remaining distance is obtained. Then, the deceleration control is started when the remaining distance that is decreasing reaches the deceleration distance, and the deceleration control is terminated when the remaining distance becomes zero and the vehicle passes the curve start point. That is, the deceleration control is executed so that the appropriate vehicle speed during the curve traveling is achieved at the curve start point.

  Moreover, in the apparatus described in Patent Document 2, the appropriate vehicle speed during curve traveling is determined based on the curve radius. Then, the determined appropriate vehicle speed is adjusted based on the road length of the section with a constant degree of flexion or the road length of the relaxation curve section (section composed of clothoid curve).

  Moreover, in the apparatus described in Patent Document 3, the following processing is performed for the purpose of acquiring a curvature change start point (that is, a curve start point). First, the starting point of a section with a constant degree of curvature in a curve on the road on which the vehicle is traveling and the curvature of that section are acquired. The section of the constant degree of flexion is identified based on the actual operation information of the vehicle (for example, a state where the steering angle is constant for a predetermined time or more). Next, information indicating a relaxation curve section (section composed of clothoid curve) connected to the constant curvature section is acquired based on the curvature of the constant curvature section. A curve start point is acquired based on the information indicating the relaxation curve section and the start point of the section with a constant degree of curvature. Then, suspension control is performed to adjust the characteristics of the suspension for the curve based on the acquired curve start point.

  That is, in the apparatus described in Patent Document 3, the curve start point is acquired based on the actual operation information of the vehicle. For this reason, in the curve where the vehicle travels for the first time, only the process of acquiring the curve start point is performed, and the suspension control cannot be executed. Suspension control is executed on the basis of the acquired curve start point in the curve that the vehicle travels for the second time or thereafter.

  Moreover, in the apparatus described in Patent Document 4, a road shape including a curve is accurately estimated based on information on a large number of node points stored in a road database. Specifically, a clothoid curve corresponding to the curve section is calculated based on the road database, and the calculated clothoid curve is adapted to the curve section. Then, the start point and end point of the curve section are accurately set on the straight section.

Japanese Patent No. 3385812 JP 2006-331000 A JP 2009-32031 A JP 2005-214839 A

  Assume that the approach relaxation curve section is long. In this case, when the deceleration control is performed so that the deceleration ends at the curve start point with reference to the curve start point as in the device described in Patent Document 1, the start / end of the deceleration control is more than the intention of the driver. The driver may feel discomfort early.

  In addition, as in the device described in Patent Document 4, in order to accurately estimate the road shape from information on a large number of node points stored in the road database, the node points are actually set densely. It is necessary. This leads to an increase in the capacity of the road database.

  The present invention has been made to cope with such a problem, and its purpose is to use a simplified road database to reduce the uncomfortable feeling given to the driver when passing a curve in front of the vehicle. An object of the present invention is to provide a vehicle speed control device that can achieve control.

  The vehicle speed control device according to the present invention includes vehicle speed acquisition means (B1), vehicle position acquisition means (B2), road shape storage means (B3), and control means (B4). Hereinafter, these means will be described in order.

  Vehicle speed acquisition means (B1) and the actual vehicle speed (Vxa) are acquired. The actual vehicle speed (Vxa) can be acquired using one of well-known methods such as a method using the output of the wheel speed sensor.

  The vehicle position acquisition means (B2) acquires the position (Pvh) of the vehicle. The vehicle position (Pvh) can be obtained by using a global positioning system or the like mounted on a navigation device mounted on the vehicle.

  The road shape storage means (B3) (road database) is composed of a curve of a road on which the vehicle travels, and a relaxation curve section and a constant curvature degree section where the curvature degree is continuous to the relaxation curve section. As the shape of the curve, the first position (Px #) which is the position of the end point (both end points) of the constant degree of flexion section (Cr #) where the degree of flexion (Rc) in the curve is constant, and the constant degree of flexion A predetermined bending degree (Rm #) of the section (Cr #) is stored in advance.

  Based on the actual speed (Vxa) of the vehicle, the vehicle position (Pvh), the first position (Px #), and the constant bending degree (Rm #), the control means (B4) The vehicle speed control (deceleration control) for controlling the speed of the vehicle is executed even when the acceleration / deceleration operation is not performed.

  As described above, in general, one curve is composed of an approach relaxation curve section, a constant bending degree section, and an exit relaxation curve section in order from the curve entrance to the curve exit. In this case, the bending degree constant section in the curve has the largest bending degree (the curvature is large, the curvature radius is small). That is, the starting point of the section with a constant degree of flexion (see point Cs in FIG. 8 and point Pxc in FIG. 3) is the point where the lateral acceleration acting on the vehicle is maximum and the vehicle is at the nearest point when passing through the curve at a constant vehicle speed. Become. Therefore, when the vehicle speed control is executed so that the vehicle passes smoothly through the curve, the starting point of the section with a constant degree of curvature (refer to the point Cs in FIG. 8 and the point Pxc in FIG. 3) and the constant degree of bending are used as a reference. It may be preferable to adjust the vehicle speed.

  The above configuration is based on such knowledge. According to this, the vehicle speed can be adjusted so that the vehicle speed decreases to an appropriate value in consideration of the constant bending degree in the vicinity of the start point of the constant bending degree section. Therefore, the vehicle speed control tends to be in line with the driver's intention in consideration of the shape of the constant bending degree section having the largest bending degree, and as a result, the uncomfortable feeling given to the driver by the vehicle speed control can be reduced. In addition, since the starting point of the section with a constant degree of flexion necessary for vehicle speed control is stored in advance in the road database, the vehicle speed control can be appropriately executed even in a curve where the vehicle travels for the first time.

  Further, in the road shape storage means (B3) (road database), “bend” which is road information necessary for performing the vehicle speed control “according to the driver's intention in consideration of the shape of the section with a constant degree of bend”. The starting point (end point position) of a certain degree section and the certain degree of bending are stored directly. That is, in the road database, instead of storing information on a large number of node points, data is stored in a format that can be directly used for the vehicle speed control. Therefore, a road database necessary for performing vehicle speed control in accordance with the driver's intention can be simplified.

  Specifically, in the vehicle speed control, a first target vehicle speed (Vt1) of the vehicle is calculated based on the first position (Px #) and the constant bending degree (Rm #), and the first target vehicle speed is calculated. The vehicle speed can be controlled based on the comparison result (ΔVx) between (Vt1) and the actual speed (Vxa) of the vehicle. According to this, the target value of the vehicle speed control can be set to a pattern in line with the driver's intention in consideration of the shape of the constant bending degree section having the largest bending degree as described above. In this case, the pattern of the first target vehicle speed is, for example, in view of setting the vehicle deceleration during vehicle deceleration to an appropriate range (or a predetermined value or less) (that is, considering the vehicle deceleration). ) Can be set.

  In this case, specifically, based on the position (Pvh) of the vehicle, the vehicle in the constant bending degree section (Cr #) existing on the road on which the vehicle is traveling ahead of the vehicle. A reference flexion degree constant section (Crc, Cri) existing at a position closest to the vehicle is determined, and the first position (Pxc, Pxi) closer to the vehicle in the reference flexion degree constant section (Crc, Cri) is determined. The reference position (Pref) is set based on the above. Then, the first target vehicle speed (Vt1) can be calculated based on the reference position (Pref) and the constant bending degree (Rmc, Rmi) of the reference bending degree constant section (Crc, Cri).

  Further, the road shape storage means (B3), as the shape of the curve, at the first position (Px #), the relaxation curve section (Eu #) of the relaxation curve section (Eu #) that is continuous to the section of constant curvature (Cr #). The second position (Py #), which is the position of the end point different from the first position (Px #), can be stored. In this case, in the vehicle speed control, the second target vehicle speed (Vt2) of the vehicle is calculated based on the first position (Px #), the second position (Py #), and the constant bending degree (Rm #). Then, the vehicle speed can be controlled based on the comparison result (ΔVx) between the second target vehicle speed (Vt2) and the actual speed (Vxa) of the vehicle. Here, the second position (Py #) used in the vehicle speed control is usually the start point of the approach relaxation curve section (that is, the end point of the approach straight section, the point Ci in FIG. 8, the point in FIG. 3). Pyb) is used.

  In general, the degree of flexion that changes from time to time in the approach relaxation curve section can be acquired based on the start / end points of the approach relaxation curve section and the constant curvature of the constant curvature degree section that follows the approach relaxation curve section. Therefore, the target value of the vehicle speed control can be set to a pattern in accordance with the driver's intention considering the shape of the approach relaxation curve section. In this case, the pattern of the second target vehicle speed is, for example, in view of setting the lateral acceleration of the vehicle while traveling in the approach relaxation curve section to an appropriate range (or a predetermined value or less) (that is, the lateral acceleration of the vehicle). Can be set).

  In this case, specifically, based on the position (Pvh) of the vehicle, the vehicle in the constant bending degree section (Cr #) existing on the road on which the vehicle is traveling ahead of the vehicle. A reference flexion degree constant section (Crc, Cri) existing at a position closest to the vehicle is determined, and the first position (Pxc, Pxi) closer to the vehicle in the reference flexion degree constant section (Crc, Cri) is determined. The second position (Pyb, Pyh) of the relaxation curve section (Eub, Euh) that is continuous with the reference bending degree constant section (Crc, Cri) at the first position (Pxc, Pxi) closer to the vehicle. And the second target vehicle speed (Vt2) can be calculated based on the constant bending degree (Rmc, Rmi) of the reference bending degree constant section (Crc, Cri).

  In the vehicle speed control, the smaller one of the first target vehicle speed (Vt1) and the second target vehicle speed (Vt2) is determined as the final target vehicle speed (Vt), and the final target vehicle speed ( The vehicle speed may be controlled based on a comparison result (ΔVx) between Vt) and the actual speed (Vxa) of the vehicle. According to this, for example, the target value for vehicle speed control is such that the vehicle deceleration during vehicle deceleration does not exceed an appropriate range (or a predetermined value), and the vehicle lateral acceleration during traveling in the approach relaxation curve section Can be set to a pattern that does not exceed an appropriate range (or a predetermined value). In other words, the target value of the vehicle speed control can be set to an appropriate pattern considering both the deceleration and the lateral acceleration of the vehicle.

  In the speed control device according to the present invention, the vehicle speed control is permitted based on the vehicle position (Pvh) and the second position (Py #, Pyb, Pyh). Determination means (B5) for determining any one of Scv, Ssg = 1) and a prohibited state (Scv, Ssg = 0) for prohibiting execution of the vehicle speed control, and the control means (B4) However, it is preferable that the vehicle speed control is executed when the permission state is determined, and the vehicle speed control is not executed when the prohibition state is determined. Also here, as the second position (Py #), the start point of the approach relaxation curve section (that is, the end point of the approach straight section, refer to the point Ci in FIG. 8 and the point Pyb in FIG. 3) can be used. .

  In this case, specifically, for example, based on the fact that the position (Pvh) of the vehicle has passed the second position (Py #, Pyb, Pyh), the determination result (Scv) of the determination means (B5) Is switched from the prohibited state (Scv = 0) to the permitted state (Scv = 1).

  According to this, it is determined whether or not the vehicle speed control can be executed in consideration of the start point of the approach relaxation curve section that is the curve entrance. Accordingly, the vehicle speed control can be started at an appropriate point according to the driver's intention.

  In particular, when a turning amount acquisition means (B6) for acquiring a turning amount (Tca, Yra) representing the degree of turning motion of the vehicle is provided, the vehicle position (Pvh) and the second position (Py #, Pyb, Pyh), the calculation of the integrated value (Ha, Ya) of the turning amount (Tca, Yra) is started based on the turning amount (Tca, Yra), and the integrated value (Ha, Ya) is predetermined. The determination result (Ssg) of the determination means (B5) may be switched from the prohibited state (Ssg = 0) to the permitted state (Ssg = 1) based on exceeding the value (ha1).

  Here, the calculation of the integrated value of the turning amount may be started when the vehicle passes through the second position (Py #, Pyb, Pyh), or the vehicle is moved to the second position (Py #, Py #, May be started after passing Pyb, Pyh) or when the vehicle passes a position closer to the front side (side closer to the vehicle) than the second position (Py #, Pyb, Pyh) by a predetermined distance. May be.

  According to this, when the road shape based on the road database stored in the navigation device does not match the actual road shape due to the road improvement (for example, the correction from the curve to the straight road), the vehicle speed control is performed. Occurrence of an unnecessarily started event can be suppressed.

1 is a schematic configuration diagram of a vehicle equipped with a vehicle speed control device according to an embodiment of the present invention. It is a functional block diagram at the time of the apparatus shown in FIG. 1 performing vehicle speed control. It is the figure which showed the typical example of the road shape containing a curve. It is the graph which showed the relationship between the position about a road shown in FIG. 3, and a bending degree. FIG. 3 is a functional block diagram when a target vehicle speed is calculated in a target vehicle speed calculation block shown in FIG. 2. It is the figure which showed an example of the road shape in case a curve and a curve are connected without passing through a straight section. It is the graph which showed the relationship between the position about the road shown in FIG. 6, and a bending degree. It is a figure for demonstrating the typical structure of the road containing a curve.

  Embodiments of a vehicle speed control device according to the present invention will be described below with reference to the drawings.

(Constitution)
FIG. 1 shows a schematic configuration of a vehicle equipped with a speed control device (hereinafter referred to as “the present device”) according to an embodiment of the present invention. This device includes an engine EG that is a power source of the vehicle, an automatic transmission TM, a brake actuator BRK, an electronic control unit ECU, and a navigation device NAV.

  The engine EG is, for example, an internal combustion engine. That is, the opening degree of the throttle valve TV is adjusted by the throttle actuator TH according to the operation of the accelerator pedal (acceleration operation member) AP by the driver. An amount of fuel proportional to the amount of intake air adjusted according to the opening of the throttle valve TV is injected by a fuel injection actuator FI (injector). Thereby, the output torque according to the operation of the accelerator pedal AP by the driver can be obtained.

  The automatic transmission TM is a multi-stage automatic transmission having a plurality of shift stages or a continuously variable automatic transmission having no shift stages. The automatic transmission TM has a reduction ratio (the rotational speed of the EG output shaft (= TM input shaft) / the rotational speed of the TM output shaft) depending on the operating state of the engine EG and the position of the shift lever (transmission operation member) SF. Can be automatically changed (without operation of the shift lever SF by the driver).

  The brake actuator BRK has a known configuration including a plurality of solenoid valves, a hydraulic pump, a motor, and the like. The brake actuator BRK supplies the brake pressure (brake hydraulic pressure) according to the operation of the brake pedal (brake operation member) BP by the driver to the wheel cylinder WC ** of the wheel WH ** and controls when not controlled. Sometimes, the braking pressure in the wheel cylinder WC ** can be adjusted for each wheel independently of the operation of the brake pedal BP (and the operation of the accelerator pedal AP).

Note that “**” at the end of each symbol is a comprehensive notation such as “fl” or “fr” that indicates which wheel each symbol is related to, and “fl” is on the left. The front wheel, “fr” indicates the right front wheel, “rl” indicates the left rear wheel, and “rr” indicates the right rear wheel. For example, the wheel cylinder WC ** is the left front wheel wheel cylinder WCfl,
A right front wheel cylinder WCfr, a left rear wheel cylinder WCrl, and a right rear wheel cylinder WCrr are shown comprehensively.

  This device includes a wheel speed sensor WS ** for detecting the wheel speed Vw ** of the wheel WH **, a braking pressure sensor PW ** for detecting the braking pressure in the wheel cylinder WC **, and a steering wheel SW ( Steering wheel angle sensor SA that detects the rotation angle (from the neutral position), yaw rate sensor YR that detects the yaw rate of the vehicle body, longitudinal acceleration sensor GX that detects acceleration (deceleration) in the longitudinal direction of the vehicle body, and lateral direction of the vehicle body Lateral acceleration sensor GY that detects acceleration, engine rotation speed sensor NE that detects the rotation speed of the output shaft of the engine EG, acceleration operation amount sensor AS that detects the operation amount of the accelerator pedal AP, and operation amount of the brake pedal BP Is provided with a brake operation amount sensor BS for detecting the shift, a shift position sensor HS for detecting the position of the shift lever SF, and a throttle valve opening sensor TS for detecting the opening of the throttle valve TV.

  The electronic control unit ECU is a microcomputer that electronically controls the powertrain system and the chassis system. The electronic control unit ECU is electrically connected to the various actuators described above, the various sensors described above, and the automatic transmission TM, or can communicate with each other via a network. The electronic control unit ECU is composed of a plurality of control units (ECU1 to ECU3) connected to each other via a communication bus CB.

  ECU1 in the electronic control unit ECU is a wheel brake control unit and controls the brake actuator BRK based on signals from the wheel speed sensor WS **, longitudinal acceleration sensor GX, lateral acceleration sensor GY, yaw rate sensor YR, etc. Thus, braking pressure control (wheel brake control) such as well-known anti-skid control (ABS control), traction control (TCS control), and vehicle stability control (ESC control) is executed.

  The ECU 2 in the electronic control unit ECU is an engine control unit that controls the throttle actuator TH and the fuel injection actuator FI based on signals from the acceleration operation amount sensor AS and the like, thereby controlling the output torque of the engine EG (engine control). Is supposed to run.

  The ECU 3 in the electronic control unit ECU is an automatic transmission control unit, and executes a reduction ratio control (transmission control) by controlling the automatic transmission TM based on a signal from the shift position sensor HS or the like. It has become.

  The navigation device NAV includes a navigation processing device PRC. The navigation processing device PRC includes vehicle position detection means (global positioning system) GPS, yaw rate gyro GYR, input unit INP, storage unit MAP, and display unit (display). ) Electrically connected to MTR. The navigation device NAV is electrically connected to the electronic control unit ECU or can communicate wirelessly.

  The vehicle position detection means GPS can detect the position (latitude, longitude, etc.) of the vehicle by one of the well-known methods using positioning signals from artificial satellites. The yaw rate gyro GYR can detect the angular velocity (yaw rate) of the vehicle body. The input unit INP is configured to input an operation related to the navigation function by the driver. The storage unit MAP (road database) stores various information such as map information and road information.

  The navigation processing device PRC comprehensively processes signals from the vehicle position detection means GPS, yaw rate gyro GYR, input unit INP, and storage unit MAP, and displays the processing results (information related to the navigation function) on the display unit MTR. It is supposed to be.

(Curve deceleration control)
Hereinafter, the curve deceleration control (vehicle speed control) executed by the apparatus configured as described above will be described. Curve deceleration control is a control that decelerates the vehicle regardless of the driver's acceleration / deceleration operation (AP, BP operation) (when acceleration / deceleration operation is not performed) so that the vehicle can pass the curve properly. is there. Vehicle deceleration is accomplished using at least one of engine EG output reduction, transmission TM downshift, and wheel brakes.

  The curve deceleration control will be described below with reference to the functional block diagram shown in FIG. First, the vehicle speed acquisition means B1 acquires the actual speed Vxa of the vehicle. The actual vehicle speed Vxa is calculated by a known method based on the detection signal (wheel speed) Vw ** of the wheel speed sensor WS **. In the vehicle position acquisition means B2, the current position Pvh of the vehicle is acquired. The vehicle position Pvh is acquired using a global positioning system (GPS).

  Hereinafter, the description will be continued with reference to FIGS. FIG. 3 shows a typical example of a road shape including a curve. FIG. 4 shows the relationship between the position and the bending degree for the road shown in FIG. In FIG. 4, curvature is used as the degree of bending.

  In the road shape storage means B3 (storage unit MAP, road database), the curvature (curvature) in the curve of the road is taken as the shape of a curve composed of a relaxation curve section and a section of constant curvature continued from the relaxation curve section. In order to define a bending degree constant section Cr # in which the radius and curvature are constant, information on the first position Px # representing both end points of Cr # (for example, longitude and latitude), and constant bending of Cr # The degree Rm # is stored in advance. In addition, information (for example, longitude and latitude) of the second position Py # that is a position of an end point different from the first position Px # of the relaxation curve section Eu # that is continuous to Cr # at the first position Px # is stored in advance. Has been. Note that “#” appended to the end of various symbols and the like is a comprehensive notation of one alphabetic character.

  In the example shown in FIGS. 3 and 4, the points Pxc and Pxd are stored as the first position Px # of the section Crc that is the constant curvature degree Cr #, and the curvature radius Rmc is stored as the constant bending degree Rm # of the section Crc. ing. The first positions Pxc and Pxd correspond to the start point and end point of the constant bending degree section Crc, respectively. In the curves shown in FIGS. 3 and 4, the bending degree constant section Crc has the largest bending degree (the curvature is large and the curvature radius is small). Therefore, the first positions Pxc and Pxd can be said to be points at both ends of the section having the highest degree of bending in the curves shown in FIGS.

  Further, the point Pyb is stored as the second position Py # of the approach relaxation curve section Eub continuous with the constant bending degree section Crc at the point Pxc, and the exit relaxation curve section Eud continuous with the constant bending degree section Crc at the point Pxd. The point Pye is stored as the second position Py #. The second position Pyb corresponds to the start point of the approach relaxation curve section Eub (curve entrance, the end point of the approach straight line section Sta), and the second position Pye is the end point of the exit relaxation curve section Eud (curve exit, exit straight section Ste. Corresponds to the starting point).

  In the vehicle speed control means B4, curve deceleration control is executed, and the vehicle speed is adjusted so that the vehicle can stably travel on a curve located ahead. The vehicle speed control means B4 includes operation blocks B41 to B44. Hereinafter, the operation blocks B41 to B44 will be described in order.

  In the target vehicle speed calculation block B41, based on the vehicle position Pvh acquired by the vehicle position acquisition means B2 and the road database, the constant curvature degree section Cr # existing on the road on which the vehicle is traveling in front of the vehicle. Among them, a section with a constant reference bending degree existing at a position closest to the vehicle is determined. Hereinafter, unless otherwise specified, the constant bending degree Rm #, the first position Px #, and the second position Py # are related to a curve including a reference bending degree constant section.

  In the target vehicle speed calculation block B41, the vehicle position Pvh acquired by the vehicle position acquisition means B2, the constant bending degree Rm # (curvature radius) of the reference bending degree constant section Cr #, and the first reference bending degree constant section Cr #. Based on the 1 position Px #, the first target vehicle speed Vt1 for appropriately passing the curve is calculated. Further, based on Pvh, Rm #, Px # and the second position Py # of the reference bending degree constant section Cr #, the second target vehicle speed Vt2 for appropriately passing the curve is calculated. Further, the final target vehicle speed Vt is calculated based on Vt1 and Vt2. Hereinafter, details of the calculation of Vt1, Vt2, and Vt in the target vehicle speed calculation block B41 will be described with reference to FIG.

  As shown in FIG. 5, in the appropriate vehicle speed calculation block B41a, an appropriate vehicle speed Vq # for stably passing through the constant reference flexion degree section Cr # is calculated based on Rm # of the reference flexion degree constant section Cr #. The As Rm # (curvature radius) increases, Vq # is calculated to a larger value. In the margin distance calculation block B41b, the margin distance Lpr is calculated based on Vq #. Lpr is calculated to a larger value as Vq # is larger. Lpr is used to determine a reference position Pref that is a point where Vq # should be achieved.

  In the first target vehicle speed characteristic calculation block B41c, the first target vehicle speed calculation characteristic Vt1ch is determined. Vt1ch is a vehicle speed characteristic with respect to the position for calculating Vt1. The reference position Pref (a point where Vq # is achieved) is determined based on the first position Px # (starting point of Cr #) and the Lpr of the reference bending degree constant section Cr #. Pref is set on the side closer to the vehicle by a margin distance Lpr with respect to the first position Px # of the reference bending degree constant section Cr #.

  Vt1ch is determined based on Pref and Vq #. Vt1ch is set to a characteristic in which the vehicle speed decreases at a deceleration Gxo (for example, a constant value) toward Pref and the vehicle speed becomes Vq # at Pref. While the data of the first position Px # and the vehicle position Pvh include an error, the error can be compensated by offsetting the reference position Pref closer to the vehicle by the margin distance Lpr as described above. . Pref can be set to the first position Px # itself (ie, Lpr can be set to 0).

  In the first target vehicle speed calculation block B41d, Pvh is substituted for Vt1ch calculated in the block B41c, and the target vehicle speed Vt1 for the vehicle position Pvh is sequentially calculated. That is, as the vehicle position Pvh moves from moment to moment, the target vehicle speed Vt1 also changes from moment to moment.

  As described above, in this example, the pattern of the target vehicle speed Vt1 is in light of the viewpoint that the vehicle deceleration during vehicle deceleration is set to an appropriate value (specifically, the Gxo) (that is, the vehicle deceleration is considered). Set).

  In the relaxation curve section bending degree calculation block B41e, the first position Px # (starting point of Cr #), the second position Py # (end point of the approach straight section), and the constant bending of the reference bending degree constant section Cr #. Based on the degree Rm #, the bending degree Rd with respect to the position Pd in the relaxation curve section Eu # having both ends of Px # and Py # is calculated. In the calculation of the bending degree Rd, it is assumed that the relaxation curve section Eu # is constituted by a clothoid curve. That is, in the relaxation curve section Eu #, it is assumed that the change of the curvature (reciprocal of the curvature radius) 1 / Rd with respect to the change (distance) of the position Pd is expressed linearly, and the bending degree Rd with respect to the position Pd is calculated. The

  In the limit vehicle speed block B41f, the limit vehicle speed Vd is calculated based on Rd. As Rd (radius of curvature) increases, Vd is calculated to a larger value. For example, Vd is set to √ (Rd · Gyo). Here, Gyo is an appropriate vehicle lateral acceleration (for example, a constant value).

  In the second target vehicle speed characteristic calculation block B41g, the second target vehicle speed calculation characteristic Vt2ch is determined. Vt2ch is a vehicle speed characteristic with respect to the position for calculating Vt2. Vt2ch is determined based on Pd and Vd. Vt2ch is set to a characteristic that the vehicle speed decreases in accordance with the limit vehicle speed Vd in the relaxation curve section Eu # and the vehicle speed becomes Vq # in Px #.

  In the second target vehicle speed calculation block B41h, Pvh is substituted for Vt2ch calculated in the block B41g, and the target vehicle speed Vt2 with respect to the vehicle position Pvh is sequentially calculated. That is, as the vehicle position Pvh moves from moment to moment, the target vehicle speed Vt2 also changes from moment to moment.

  As described above, in the present example, the pattern of the target vehicle speed Vt1 is in light of the viewpoint that the lateral acceleration of the vehicle during traveling in the approach relaxation curve section Eu # is set to an appropriate value (specifically, the Gyo) (that is, Set in consideration of the lateral acceleration of the vehicle).

  In the minimum value selection calculation block B41i, the smaller vehicle speed of Vt1 and Vt2 is determined as the final target vehicle speed Vt. As a result, the target vehicle speed Vt is set so that the vehicle deceleration during vehicle deceleration does not exceed an appropriate value (the Gxo (for example, a predetermined value set in advance)) and the vehicle is traveling in the approach relaxation curve section Eu #. The lateral acceleration of the vehicle may be set to a pattern that does not exceed an appropriate value (the Gyo (for example, a predetermined value set in advance)). In other words, the target vehicle speed Vt can be set to an appropriate pattern considering both the deceleration and lateral acceleration of the vehicle.

  One of Vt1 and Vt2 can be omitted. When Vt1 is omitted (that is, when blocks B41a to B41d are omitted), Vt2 is calculated as the final target vehicle speed Vt. When Vt2 is omitted (that is, when blocks B41e to B41h are omitted), Vt1 is calculated as the final target vehicle speed Vt. The details of the calculation in the target vehicle speed calculation block B41 of the vehicle speed control means B4 in FIG. 2 have been described above.

  Referring to the vehicle speed control means B4 in FIG. 2 again, in the comparison calculation block B42, any one of the target vehicle speeds Vt1, Vt2, and Vt and the actual vehicle speed (actual vehicle speed) Vxa acquired by the vehicle speed acquisition means B1 are obtained. To be compared. Specifically, a deviation ΔVx (ΔVx = Vxa−Vt or the like) between Vxa and any one of Vt1, Vt2, and Vt is calculated. The switching calculation block B43 will be described later.

  In the vehicle speed adjusting means B44, the vehicle speed is adjusted based on the comparison result ΔVx. The vehicle speed adjusting means B44 applies a friction brake (wheel brake) and / or a so-called engine brake (TM shift down) to the vehicle to decelerate the vehicle (even when acceleration / deceleration operation is not performed by the driver). Or means for limiting the opening of the throttle valve TV and / or the injection amount of the injector FI in order to limit the acceleration of the vehicle.

  For example, when ΔVx is a positive value, the vehicle speed adjusting unit B44 operates so that ΔVx is 0 or less (so that the actual vehicle speed is less than or equal to the target vehicle speed). That is, the start condition of the curve deceleration control is established based on the fact that ΔVx becomes a positive value (the actual vehicle speed Vxa exceeds the target vehicle speed (Vt, etc.)). The vehicle speed adjusting means B44 executes curve deceleration control, the vehicle is decelerated, and acceleration is limited. The vehicle speed control means B4 has been described above.

  In the determination means B5, it is determined whether or not the curve deceleration control can be executed. When the determination result of the determination means B5 is in a prohibition state in which execution of the curve deceleration control is denied, the “curve deceleration control start condition (actual vehicle speed) in relation to one of the target vehicle speeds Vt1, Vt2, and Vt and the actual vehicle speed Vxa. Is greater than the target vehicle speed), the curve deceleration control is not started. On the other hand, the curve deceleration control is started when the “curve deceleration control start condition” is satisfied only when the determination result is in a permission state in which execution of the curve deceleration control is affirmed.

  More specifically, in the relaxation curve section approach determination block B51, based on the vehicle position Pvh and the second position Py # (latitude / longitude information) of the reference flexion degree constant section Cr #, the vehicle It is determined whether or not the vehicle has entered the approach relaxation curve section Eu # (that is, whether or not the vehicle has passed Py #). When it is determined that the vehicle has entered Eu #, the signal (control flag) Scv is changed from the prohibited state (which has been maintained so far) (Scv = 0) to the permitted state (Scv = 1). In the example shown in FIGS. 3 and 4, Scv is changed from “0” to “1” when the vehicle passes through the point Pyb.

  Based on the change of the control flag Scv from “0” to “1”, in the switching calculation block B43 of the vehicle speed control means B4, the comparison result by the comparison calculation block B42 from the execution prohibition (ΔVx = 0) side. It is switched to the (ΔVx) side. Thereby, output of the comparison result ΔVx by the comparison calculation block B42 is started to the vehicle speed adjusting means B44. At this time, if the “condition for starting the curve deceleration control” is already satisfied, the curve deceleration control is immediately started. Otherwise, the curve deceleration control is started when the “curve deceleration control start condition” is satisfied thereafter.

  As described above, the curve deceleration control is permitted only when the vehicle position is within the curve. That is, execution of the curve deceleration control is prohibited while the vehicle is traveling on the straight line section of the road. Therefore, it is possible to suppress the unnecessary execution of the curve deceleration control when the target vehicle speeds Vt1, Vt2, and Vt are erroneously calculated. Thus, the reliability of execution of the curve deceleration control can be improved by the process of the determination unit B5.

  Further, turning amount acquisition means B6 for acquiring the turning amount Tca of the vehicle is provided. The turning amount Tca represents the degree of turning motion of the vehicle. Specifically, Tca is any one of steering wheel operation angle θsw, steering wheel steering angle δfa, actual yaw rate Yra, and actual lateral acceleration Gya, or any two or more thereof. Based on the value. Hereinafter, the steering wheel operation angle θsw and the steering angle δfa of the steered wheel are collectively referred to as a steering angle Sa. The turning amount Tca is a value calculated based on Sa, Yra, Gya itself, or Sa, Yra, Gya.

  When the relaxation curve section entry determination block B51 determines that the vehicle has passed the second position Py # (that is, the vehicle has entered Eu #) as described above, the integral calculation from zero of Tca is performed. (Integration calculation) is started, and thereafter, the integrated value Ha of Tca is calculated. When the integrated value Ha exceeds the predetermined value ha1, the signal (control flag) Ssg is changed from the prohibited state (which has been maintained so far) (Ssg = 0) to the permitted state (Ssg = 1).

  For example, when the actual yaw rate Yra is used as Tca, when the vehicle passes Py # (end point of the approach straight line section), the yaw angle (azimuth representing the direction of the vehicle) Ya, which is an integrated value of Yra, The calculation is started. When Ya exceeds a predetermined value ha1, the execution of the curve deceleration control is changed from the prohibited state (Ssg = 0) to the permitted state (Ssg = 1). As a result, as in the case where the control flag Scv is changed from “0” to “1”, the state of the switching calculation block B43 of the vehicle speed control means B4 is changed from the execution prohibited (ΔVx = 0) side to the comparison calculation block B42. Is switched to the comparison result (ΔVx) side.

  Thus, it is determined whether or not the curve deceleration control can be executed based on Tca. For this reason, in the case where the road is modified (for example, the road is modified from a curve to a straight road) and the road shape based on the road information stored in the storage unit MAP no longer matches the actual road shape, etc. Unnecessary execution of curve deceleration control can be suppressed.

  Here, as the turning amount Tca, instead of the actual yaw rate Yra, the calculated yaw rate Yre1 calculated based on the vehicle speed Vxa and the steering angle Sa (steering wheel operation angle θsw, steering wheel steering angle δfa), the left and right wheels At least one of the calculated yaw rate Yre2 calculated based on the speed difference and the calculated yaw rate Yre3 calculated based on the vehicle speed Vxa and the lateral acceleration Gya may be used.

  In the above description, the calculation of the integrated value Ha from zero of the turning amount Tca is started when the vehicle passes the second position Py #, but is started after the vehicle passes the second position Py #. May be. Alternatively, the processing may be started when the vehicle passes a position (a position in the straight section) that is closer to the second position Py # by a predetermined distance. This is because Pvh and the like contain an error, so it is necessary to start the integration of Tca from zero before Py #, but the side before Py # corresponds to a straight line section, and within the straight line section. This is based on the fact that Ha is maintained at zero over the straight line section even if the calculation of the integrated value Ha is started.

  As described above, according to the speed control device according to the embodiment of the present invention, in the road database, the road on which the vehicle travels as the shape of a curve composed of a relaxation curve section and a constant bending degree section that is continuous to the section. In order to define a constant bending degree section Cr # (“#” at the end of the symbol is a comprehensive notation of one alphabetic character) where the bending degree in the curve is constant, the first position which is the end point position of the constant bending degree section Cr # Px # (latitude / longitude information) and a constant bending degree Rm # of a constant bending degree section Cr # are stored in advance. On the basis of the vehicle position Pvh, a reference flexion degree constant section existing at a position closest to the vehicle is determined among the constant curvature degree sections Cr # existing on the road on which the vehicle is traveling in front of the vehicle. Then, based on the actual vehicle speed Vxa, the constant bending degree Rm # of the reference bending degree constant section Cr #, and the first position Px # of the reference bending degree fixed section Cr # (acceleration / deceleration operation by the driver is not performed). Curve deceleration control is performed in order for the vehicle to properly pass the curve (even if not).

  In a typical curve composed of an approach relaxation curve section, a constant bending degree section, and an exit relaxation curve section in order from the curve entrance to the curve exit, the constant bending degree section Cr # has the highest bending degree in the curve. Large (curvature is large, radius of curvature is small). That is, the starting point (point Pxc in FIG. 3) of the constant bending degree section Cr # has the maximum lateral acceleration acting on the vehicle when passing through the curve at a constant vehicle speed and is the closest point. Therefore, when the curve deceleration control is executed so that the vehicle passes smoothly through the curve, the starting point of the constant bending degree section Cr # (point Pxc in FIG. 3) and the constant bending degree Rm # (curvature radius Rmc in FIG. 3). It is preferable that the vehicle speed is adjusted based on at least the above.

  According to the present embodiment, in the curve deceleration control, the vehicle speed is adjusted so that the vehicle speed decreases to an appropriate value Vq # in consideration of the constant bending degree Rm # in the vicinity of the start point Px # of the constant bending degree section Cr #. obtain. Therefore, the curve deceleration control is likely to be in line with the driver's intention considering the shape of the constant bending degree section where the bending degree is the largest, and as a result, the uncomfortable feeling given to the driver by the curve deceleration control can be reduced. it can. In addition, since the starting point of the constant bending degree section Cr # necessary for the curve deceleration control is stored in advance in the road database, the curve deceleration control can be appropriately executed even on the curve where the vehicle travels for the first time.

  In addition, in the road database, the road information necessary for performing the curve deceleration control “in line with the driver's intention in consideration of the shape of the section with a constant degree of curvature”, that is, “the starting point of the section with a constant degree of curvature ( The end point position) and the constant bending degree itself are directly stored. That is, in the road database, instead of storing information on a large number of node points, data is stored in a format that can be directly used for the curve deceleration control. Therefore, the road database required for performing the curve deceleration control according to the driver's intention can be simplified.

  Hereinafter, a case where a curve and a curve are connected without going through a straight section will be described with reference to FIGS. FIG. 6 shows an example of a road shape including a composite curve in which a curve and a curve are connected without going through a straight section. FIG. 7 shows the relationship between the position and the bending degree for the road shown in FIG.

  In the example shown in FIGS. 6 and 7, the bending directions of the two continuous curves coincide with the case where the bending directions of the two continuous curves are different (two continuous curves including the constant bending degree sections Clf and Cri). There are cases (two continuous curves including sections Crk and Cri having a constant degree of bending). Hereinafter, these cases will be described separately.

<When the bending directions of two consecutive curves are different>
Description will be made assuming that the vehicle traveling direction is (A) shown in FIGS. In this case, relaxation curve sections having different bending directions between a bending degree constant section Crf whose bending direction is the right direction when viewed from the vehicle and a bending degree constant section Cri whose bending direction is the left direction when viewed from the vehicle. The boundary position (connection position) Pyh between the two is handled as the second position Py #, and the above-described curve deceleration control is executed. At this boundary position Pyh, the curvature of the road is approximately “0”.

<When the bending directions of two consecutive curves match>
Description will be made assuming that the vehicle traveling direction is (B) shown in FIGS. In this case, the end point position of the constant bending degree section having the larger bending degree (the one with the smaller curvature radius or the larger curvature) is treated as the first position Px #, and the one with the smaller bending degree (the curvature radius). The end point position of the section with a constant degree of curvature (the larger one and the smaller curvature) is treated as the second position Py #. That is, assuming that the curvature radius Rmi <Rmk, the point Pxj is treated as the first position Px #, the point Pxk is treated as the second position Py #, and the above-described curve deceleration control is executed.

  BP ... brake pedal, AP ... accelerator pedal, WS ** ... wheel speed sensor, PW ** ... braking pressure sensor, TS ... throttle valve opening sensor, TH ... throttle actuator, FI ... fuel injection actuator, BRK ... brake actuator, EG ... Engine, ECU ... Electronic control unit, NAV ... Navigation device, GPS ... Global positioning system, MAP ... Memory

Claims (8)

Vehicle speed acquisition means for acquiring the actual speed of the vehicle;
Vehicle position acquisition means for acquiring the position of the vehicle;
A curve of a road on which the vehicle travels is formed of a relaxation curve section and a constant curvature degree section having a constant curvature degree that is continuous with the relaxation curve section. Road shape storage means for storing a first position which is a position, and a certain degree of bending of the certain degree of bending degree section;
Control means for executing vehicle speed control for controlling the speed of the vehicle based on the actual speed of the vehicle, the position of the vehicle, the first position, and the constant bending degree;
A vehicle speed control device. The vehicle speed control device according to claim 1,
The control means includes
Based on the first position and the constant bending degree, a first target vehicle speed of the vehicle is calculated,
A vehicle speed control apparatus that executes the vehicle speed control based on a comparison result between the first target vehicle speed and an actual speed of the vehicle. The vehicle speed control device according to claim 2,
The control means includes
Based on the position of the vehicle, a reference flexion degree constant section existing at a position closest to the vehicle among the constant curvature degree sections existing on the road on which the vehicle is traveling in front of the vehicle. Decide
A reference position is set based on the first position on the side closer to the vehicle in the reference bending degree constant section,
A speed control device for a vehicle that calculates the first target vehicle speed based on the reference position and a constant curvature of the reference curvature constant section. The vehicle speed control device according to claim 1,
The road shape storage means
As the shape of the curve, a second position that is a position of an end point different from the first position of the relaxation curve section that is continuous with the constant bending degree section at the first position is stored.
The control means includes
Based on the first position, the second position, and the constant bending degree, a second target vehicle speed of the vehicle is calculated,
A vehicle speed control device that executes the vehicle speed control based on a comparison result between the second target vehicle speed and an actual speed of the vehicle. The vehicle speed control device according to claim 4,
The control means includes
Based on the position of the vehicle, a reference flexion degree constant section existing at a position closest to the vehicle among the constant curvature degree sections existing on the road on which the vehicle is traveling in front of the vehicle. Decide
The first position on the side closer to the vehicle in the constant reference bending degree section, the second position of the relaxation curve section that is continuous with the reference bending degree constant section at the first position on the side close to the vehicle, and A vehicle speed control device that calculates the second target vehicle speed based on a certain degree of bending of the reference bending degree constant section. The vehicle speed control device according to claim 4 or 5,
Based on the position of the vehicle and the second position, determination means for determining any one of a permission state in which execution of the vehicle speed control is permitted and a prohibition state in which execution of the vehicle speed control is prohibited With
The control means includes
A vehicle speed control device that executes the vehicle speed control when the permission state is determined and does not execute the vehicle speed control when the prohibition state is determined. The vehicle speed control device according to claim 6,
The determination means includes
A speed control device for a vehicle that switches a determination result of the determination unit from the prohibited state to the permitted state based on the fact that the position of the vehicle has passed the second position. The vehicle speed control device according to claim 6,
A turning amount obtaining means for obtaining a turning amount representing a degree of turning movement of the vehicle;
The determination means includes
Based on the position of the vehicle and the second position, calculation of the integrated value of the turning amount based on the turning amount is started,
A speed control device for a vehicle that switches a determination result of the determination unit from the prohibited state to the permitted state based on the integrated value exceeding a predetermined value.

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