JP2006213294A - Brake control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control a braking unit, such as a brake, in a car to keep a car speed at a target speed or lower while maintaining riding comfort as the car runs down a sloped road. <P>SOLUTION: In a brake control system 1000, a CPU 110 stores a slope angle detected by a slope angle meter 500 in a RAM 130 when the car 10 starts to climb up a slope road, the slope angle being stored as slope angle data related in correspondence to a climbing start position defined as a cardinal point. A trigger position is determined at the top of the slope road, and the CPU 110 sets a target speed for running down in a target speed setting subject section with the cardinal point of the trigger position and the termination of the climbing start position on the basis of the slope angle data stored in the RAM 130. When the car 10 runs down the slope road, the trigger position is detected to execute a speed maintaining mode, under which a brake actuator 200 is controlled so that the speed of the car 10 does not exceed the preset target speed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technical field of a braking control system for maintaining a vehicle speed below a target speed, such as downhill assist control.

  As this type of technology, a technology has been proposed in which a driver operates by turning on a start switch and selecting a slope descent mode (see, for example, Patent Document 1). According to the wheel vehicle described in Patent Document 1 (hereinafter referred to as “conventional technology”), when the detected vehicle speed exceeds a threshold value in the slope descent mode, the vehicle changes according to the exceeded value. It is said that the vehicle speed is maintained at a threshold value by increasing the braking force at a rate and decreasing the vehicle speed. It is also possible to set the threshold according to the slope of the slope and set the threshold according to the inclination angle detected when the slope is lowered.

  In addition, when maintaining a vehicle speed, the technique which controls a braking force automatically in order of an engine brake, an auxiliary brake, and a downshift, and approaches a predetermined speed is also proposed (for example, refer patent document 2).

  In addition, a technique for maintaining the vehicle speed at a constant value and maintaining the vehicle speed at a lower vehicle speed when there is no accelerator operation has been proposed (see, for example, Patent Document 3).

Japanese National Patent Publication No. 10-507145 JP-A-9-207613 JP 20049751 A

  The gradient of the road surface on which the vehicle travels is not constant. For example, it is quite possible that the road surface condition suddenly changes from a relatively gentle gradient to a relatively steep gradient. In the prior art, it is possible to set a threshold for the vehicle speed according to the slope of the slope, but if the amount of change in the slope is large, the setting of the vehicle speed according to the slope is used to accelerate the vehicle. Abrupt braking is performed without being able to follow, which may cause discomfort to the occupant. For the purpose of avoiding such a situation, if the vehicle speed threshold is set to a fixed value unrelated to the gradient, it is easy to give the passenger a very uncomfortable feeling. That is, the conventional technique has a technical problem that comfort is easily lost when maintaining the vehicle speed.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a braking control system capable of maintaining the vehicle speed without impairing comfort.

  In order to solve the above-described problem, a braking control system according to the present invention includes a braking unit that brakes a vehicle, an inclination angle detection unit that detects an inclination angle of a slope on which the vehicle travels, and the detected inclination angle. Storing in association with a position on the slope, target speed setting means for presetting a target speed when the vehicle descends the slope based on the stored inclination angle, Control means for controlling the braking means so that the speed of the vehicle is equal to or lower than the preset target speed when the vehicle descends the slope.

  The “braking means” according to the present invention is a means for braking the vehicle, and is a concept including a mechanism called a brake or a brake system, for example. In this case, for example, a hydraulic (for example, hydraulic) control system such as a drum system or a disk system can be adopted, and these are further combined with a control system for preventing wheel locking such as an anti-lock brake system. It is also possible to use it. Moreover, the braking means according to the present invention may have a mechanical structure for enhancing the heat dissipation effect.

  According to the braking control system of the present invention, the inclination angle of the slope is detected by the inclination angle detection means during the operation.

  The “slope” in the present invention is a concept indicating a road on which at least a part is inclined, on which a vehicle can travel. Further, the inclination angle detection means in the present invention may have any aspect as long as it can detect the inclination angle of the slope, but for example, a known technique such as an inclination angle sensor or an inclination angle sensor is available. It is realized relatively easily by being applied. The accuracy of the slope angle of the slope detected by the slope angle detection means is not particularly limited as long as the effect according to the present invention is ensured.

  According to the braking control system of the present invention, the speed of the vehicle (hereinafter referred to as “vehicle speed” as appropriate) is maintained below the target speed by the control means, for example, when the vehicle descends the slope. (Hereinafter, referred to as “speed maintenance control” as appropriate).

  The speed maintenance control is executed, for example, when the driver gives an instruction to execute the speed maintenance control, and the control means controls the braking force of the braking means to keep the vehicle speed below the target speed. To do. When the vehicle speed maintenance control is performed, for example, the vehicle speed sensor or the wheel speed sensor detects that the vehicle speed has exceeded the target speed, and the braking force of the braking means is increased and controlled so that the vehicle speed does not exceed the target speed. The Therefore, as a result of the braking means being controlled to “below the target speed”, the vehicle speed is ideally maintained at the target speed. However, the vehicle speed does not necessarily have to be maintained at the target speed as long as it is maintained below the target speed. Such control of the braking force may have any form as long as the vehicle speed can be maintained. For example, the braking means controls the braking force by hydraulic pressure (for example, hydraulic pressure). When the method is employed, the hydraulic pressure may be controlled. In this case, the aspect of controlling the hydraulic pressure is not limited at all.

  The target speed when descending on a slope may be a constant vehicle speed with respect to the slope angle of the slope, but there is a possibility that the driver may feel uncomfortable with such a constant vehicle speed. It is set according to the inclination angle of the slope by means. Note that “according to the inclination angle” means that the correspondence is not limited as long as there is some correspondence. For example, if the inclination angle is relatively large (that is, if the gradient is steep), the vehicle speed will be relatively low, and if the inclination angle is relatively small (that is, if the gradient is gentle). The target speed is set so that the vehicle speed is relatively high. The correspondence relationship between the tilt angle and the target speed may be suitably determined in advance experimentally, empirically, or based on simulations.

  Here, in particular, when the inclination angle is detected and the target speed is set while the vehicle is descending the slope, as described above, depending on the inclination angle of the slope, for example, the inclination angle is detected and the target speed is set. A series of processes such as setting, detecting the current vehicle speed and outputting the braking force required for the braking means cannot follow the rapid acceleration of the vehicle, and the vehicle may be suddenly braked. Alternatively, the original meaning of maintaining the vehicle speed at the target speed may be hindered by performing slow deceleration to avoid sudden braking. Therefore, the braking control system according to the present invention solves the problem by setting the target speed when the target speed setting means descends the slope in advance, as will be described below.

  According to the braking control system of the present invention, during the operation, the detected inclination angle is stored in the storage means in association with the position on the slope.

  The “storage means” according to the present invention refers to means capable of storing the detected tilt angle regardless of whether it is temporary (volatile) or long-term (nonvolatile). In the former case, for example, a buffer It may be a memory, a RAM (Random Access Memory), or the like, and in the latter case, for example, a magnetic recording medium such as an HD (Hard Disk) or an optical information recording medium such as a DVD and a drive device corresponding thereto. May be. The inclination angle is detected as a physical or electrical signal having a corresponding relationship with the inclination angle in accordance with the aspect of the inclination angle detection means, and when stored in the storage means, the storage means Depending on the mode, these signals are stored as data representing the tilt angles corresponding to these signals or the signals.

  Here, the “position on the slope” may be expressed in any manner as long as the position on the slope corresponding to the detected inclination angle can be defined. For example, when a positioning system capable of detecting the absolute position of a vehicle represented by, for example, latitude, longitude, and altitude, such as GPS (Global Positioning System), is mounted on the vehicle, the absolute position may be used. . Further, it may be a relative position on a slope defined based on a travel distance calculated from the vehicle speed and time. In this case, more specifically, it may be a relative distance represented by a distance from a storage start position that is arbitrarily set on a slope or based on some condition. Alternatively, the position on the slope may be simply a time-series order when the inclination angle is detected at a constant timing during traveling at a constant speed.

  It should be noted that the position associated with the inclination angle may be a discrete position on the slope as long as the inclination of the slope is considerably clear as compared with the case where such inclination angle information is not generated. It may be a continuous position. In the case of being associated with continuous positions, for example, the inclination angle may be stored with visual information representing the sectional shape of the slope.

  The target speed setting means is configured to be able to set in advance the target speed when the vehicle descends the slope based on the inclination angle associated with the position on the slope. Here, “preliminarily set” means that the descent of the slope is not necessarily limited as long as the target speed at the position is set before the vehicle enters the position on the slope where the inclination angle has been detected in the past. This means that not all target speed settings need to be completed before starting. That is, the target speed may be set during a period when the vehicle is descending on the slope.

  As described above, according to the braking control system according to the present invention, the target speed when descending the slope is set according to the inclination angle, so that the driver does not feel uncomfortable. Furthermore, since the target speed is set in advance based on the stored inclination angle, a sudden braking does not occur when the vehicle descends the slope while performing the speed maintenance control. That is, the speed maintenance control can be executed without impairing comfort.

  It should be noted that the target section for setting the target speed (the section for which speed maintenance control is desired) may not be the entire section where the inclination angle is stored on the slope. For example, the system may be configured so that the driver himself can set the target section, or the target section may be automatically set according to the detected inclination angle.

  Note that the storage of the tilt angle may be performed when climbing a slope, or may be performed when descending without performing speed maintenance control. However, it is possible to set the target speed relatively accurately when the inclination angle is memorized while climbing up the slope, and when turning around the top and descending the same slope again. In this case, if the position on the slope associated with the inclination angle is not an absolute position by a positioning system or the like, but is a position that is processed in time series from the start position of storage, the target at the time of descending on the slope The target speed is set so that the latest position in the target section becomes the start position of the speed maintenance control and the oldest position in the time series becomes the end position of the speed maintenance control in the form of going back the time axis. It may be set.

  In one aspect of the braking control system according to the present invention, trigger position determining means for predetermining a trigger position serving as a base point for controlling the braking means on the slope, and the trigger position when descending the slope Trigger position detecting means for detecting the target speed, the target speed setting means sets the target speed based on the trigger position, and the control means is configured to control the control means when the trigger position is detected. To control.

  According to this aspect, the trigger position is determined on the slope by the trigger position determining means.

  Here, the “trigger position” according to the present invention is a position that is a base point for the control means to control the braking means when descending the slope, in other words, a target speed setting target section when descending on the slope. This is the base point. For example, a typical trigger position is a position corresponding to the top of a slope. However, in view of the case where there is a temporary flat road called a “dancing place” in the middle of the slope, it is determined whether it is the top of the slope, that is, whether the slope is finished. It may be made after passing through the top position to some extent. In this case, the top position of the slope may be determined as the trigger position in the form of going back on the time axis. Further, the top of the slope is not necessarily determined as the trigger position. Further, the system may be configured so that the driver himself can determine the trigger position.

  The determined trigger position is detected by the trigger position detecting means when descending the slope. Here, the manner in which the trigger position is detected is free as long as it is possible to detect a predetermined trigger position when descending a slope related to the future from the end of hill climbing, but the trigger position is, for example, It may be detected based on the absolute value of the tilt angle at the trigger position or the transition of the tilt angle in an appropriate range including the trigger position and before and after the trigger position. For example, when the positioning system as described above is provided, the trigger position may be detected based on information indicating the absolute position of the trigger position.

  According to this aspect, since the control unit controls the braking unit when the trigger position is detected, that is, the speed maintaining control is performed, the speed maintaining control can be efficiently executed.

  In one aspect of the braking control system according to the present invention in which the target speed is set based on the trigger position, the trigger position determining means receives the input to determine the trigger position. A corresponding position on the slope is determined as the trigger position.

  According to this aspect, since the trigger position is determined as a position corresponding to the input when an input for determining the trigger position is performed, the trigger position can be appropriately determined.

  For example, the “input” is a concept defined including an input that is artificially performed by a driver or the like through a physical or mechanical input means such as a button, a lever, a dial, or a switch. . When the trigger position is determined by the driver himself, the driver's own preference can be reflected, and thus comfort can be improved.

  Note that such input includes not only input by such an operation by the driver or external operation, but also input from another controller or device when some condition is satisfied. That is, input may be performed without an external operation by the driver. In this case, the conditions for determining the trigger position may be determined in advance experimentally, empirically, or by simulation, or may be configured so that the driver can input desired conditions. Good.

  In another aspect of the braking control system according to the present invention in which the target speed is set based on the trigger position, the trigger position determining means determines the trigger position based on the slope angle of the slope.

  According to this aspect, the trigger position is determined based on the slope angle of the slope, which is efficient. Here, the trigger position determined “based on the slope angle of the slope” is, for example, a position where the absolute value of the slope angle detected when climbing the slope is less than a predetermined value (below the predetermined value). Alternatively, it may be a position where the change amount of the inclination angle is equal to or larger than a predetermined value (larger than the predetermined value). Also, an algorithm for determining the trigger position may be provided in advance in case the slope has a complicated shape. With such an algorithm, for example, parameters such as the inclination angle of the position where the slope starts, the transition of the inclination angle, and the current inclination angle are given in advance experimentally, empirically, or by simulation or the like. An algorithm that compares with a standard may be used.

  In another aspect of the braking control system according to the present invention in which the target speed is set based on the trigger position, the trigger position detection means receives the input indicating that the trigger position has been detected. A corresponding position on the slope is detected as the trigger position.

  According to this aspect, when an input indicating that the trigger position is detected is performed, the trigger position is detected as a position corresponding to the input.

  For example, the “input” is a concept defined including an input that is artificially performed by a driver or the like through a physical or mechanical input means such as a button, a lever, a dial, or a switch. . For example, if the driver himself / herself has stored the trigger position, the driver himself / herself can detect the trigger position relatively accurately based on the scenery and landmarks spreading in front of him. Further, when the trigger position can be detected manually as described above, it is also effective as a preliminary means when the trigger position cannot be automatically detected.

  Note that such input includes not only input by such an operation by the driver or external operation, but also input from another controller or device when some condition is satisfied. That is, input may be performed without an external operation by the driver. In this case, the conditions for detecting the trigger position may be determined in advance experimentally, empirically, or by simulation, or may be configured so that the driver can input desired conditions. Good.

  In another aspect of the braking control system according to the present invention in which the target speed is set based on the trigger position, the trigger position detecting means detects the trigger position based on the detected inclination angle.

  According to this aspect, the trigger position is detected based on the slope angle of the slope, which is efficient. Here, the trigger position detected “based on the inclination angle of the slope” may be, for example, a position where the absolute value of the inclination angle and the inclination angle at the trigger position is equal, or includes the trigger position and the trigger position. When a suitable range that follows each other and a range in which the transition of the tilt angle coincides with each other, a position corresponding to the trigger position in the range may be used. Further, an algorithm for detecting the trigger position may be provided in advance in case the slope has a complicated shape.

  In another aspect of the braking control system according to the present invention, the target speed setting means determines the target speed based on a map in which a value serving as a reference for the target speed is predetermined according to the inclination angle of the slope. Set.

  Here, the “map” in this aspect has any format as long as a reference value of the target speed (hereinafter referred to as “reference value” as appropriate) is determined according to the inclination angle. However, for example, it may be a two-dimensional map in which the inclination angle and the reference value are arranged on the horizontal axis and the vertical axis, respectively. In this case, the reference value of the target speed may be given as a profile (characteristic curve) defined in advance on the map. Alternatively, the map may be given as a matrix in which the inclination angle and the reference value are associated one-to-one.

  The “target speed reference value” is a concept indicating that the target speed corresponding to the inclination angle may be changed according to the driving situation of the vehicle or the preference of the driver. If not, it is simply a concept equivalent to the target speed. The reference value of the target speed may be set in advance as a value that can satisfy a relatively large number of drivers, for example, experimentally, empirically, or by simulation.

  According to this aspect, since the target speed setting means sets the target speed based on the map, the processing load related to the target speed setting is reduced, and the speed maintenance control is executed more comfortably.

  In this aspect, when the speed of the vehicle is changed by operating at least one of an accelerator pedal and a brake pedal during a period when the vehicle is descending the slope at the set target speed, You may further comprise the map update means which updates the said value used as the said reference | standard in the said map according to the said changed speed.

  Sensitivity to speed is unique to each driver. For example, there are naturally drivers who feel that the reference value is “fast” and drivers who feel that the reference value is “slow” when descending a slope having a certain inclination angle with the reference value of the target speed. In view of such circumstances, inconvenience may occur if the target speed is fixed at the reference value.

  Therefore, when the vehicle speed while descending the slope is changed by operating at least one of the accelerator pedal and the brake pedal, the updated speed is reflected in the reference value of the map to update the driver's It is possible to execute speed maintenance control that fits the sensitivity. When the reference value is updated, a driver-specific target speed pattern may be separately generated, or the reference value itself may be changed.

  In another aspect of the braking control system according to the present invention, the target speed setting means is more relative to a case where the vehicle moves backward and descends the slope than to a case where the vehicle moves forward and descends the slope. Is set as the target speed.

  For example, when a vehicle climbs a hill with relatively severe driving conditions called a dirt road or an off-road, the vehicle may fall into a state where it cannot advance further on the hill. In such a case, there is no choice but to descend down the slope from that position, but in general, the backward movement is harder to drive than the forward movement, so the physical or mental load on the driver tends to increase. .

  According to this aspect, when the vehicle is going backward and descending the slope, a relatively low speed is set as the target speed as compared with the case where the vehicle is descending and moving forward, so the sense of security given to the driver is dramatically increased. To improve.

  Note that “relatively low” indicates, for example, a state in which a target speed corresponding to a certain inclination angle is lower when going downhill in reverse. For example, when the target speed is given in the form of the map described above, such a relatively low target speed may be given as a reference value for backward movement, or the target speed for forward movement may be Alternatively, it may be given by multiplying a predetermined attenuation factor.

  In another aspect of the braking control system according to the present invention, the braking control system further includes unevenness detecting means for detecting unevenness on the slope, and the storage means stores the detected unevenness in association with the position on the slope. The target speed setting means further sets the target speed based on the stored unevenness.

  According to this aspect, the unevenness on the slope is detected by the unevenness detecting means. Here, the aspect of the unevenness detecting means according to the present invention is not limited as long as the unevenness on the slope can be detected regardless of whether it is direct or indirect. For example, the unevenness may be detected indirectly by a vibrometer that detects vibration during traveling. Further, the unevenness may be detected based on a two-dimensional or three-dimensional shaking state detected by a roll sensor, a roll angle sensor, an acceleration sensor, or the like. Alternatively, when the degree of unevenness (unevenness level) can be determined in advance from information acquired from a car navigation system or the like, the unevenness may be detected based on such information.

  In general, on a slope with little or less unevenness and a slope with more or less unevenness, the latter is more uncomfortable for the driver when descending at the same slope speed. According to this aspect, since the target speed detection means sets the target speed based on the detected unevenness, speed maintenance control considering discomfort given to the driver is possible, and the downhill is descended. Comfort is guaranteed.

  In this aspect, the target speed setting means may set the target speed so that the target speed becomes relatively small as the unevenness increases.

  As described above, in general, the more unevenness or the greater the unevenness, the more uncomfortable, so when the target speed is set relatively small according to the increase in the unevenness, the unevenness of the slope is efficiently reduced. It can be reflected in the target speed. Note that the correspondence between the unevenness and the target speed may be appropriately determined in advance experimentally, empirically, or based on simulation.

  Such an operation and other advantages of the present invention will be clarified by embodiments described below.

<Embodiment of the Invention>
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<1: First Embodiment>
<1-1: Configuration of Embodiment>
<1-1-1: Vehicle configuration>
First, the configuration of the vehicle 10 according to the first embodiment of the present invention will be described with reference to FIG. Here, FIG. 1 is a schematic view of the vehicle 10.

  In FIG. 1, a vehicle 10 is an example of a “vehicle” according to the present invention, and is a four-wheel drive vehicle. The vehicle 10 includes an engine 11 that is a power source. The engine 11 is, for example, a gasoline engine. The engine 11 transmits a rotational driving force output from the engine 11 to a driving shaft 14F and a driving shaft 14R, which will be described later, and a transmission 12 and a transfer (sub-motor) for decelerating (shifting) the rotation of the rotational driving force. A transmission 13 is connected.

  The transmission 12 is an automatic transmission (AT) that can automatically select an appropriate gear (gear ratio) according to the traveling state of the vehicle 10 from a plurality of gears (gear ratio). The shift position (range) of the transmission 12 is selected by the driver operating the shift lever 12a. While the vehicle 10 is traveling, the driver usually shifts to the “D range”, which is a shift position for automatically shifting gears in four stages from the first gear (large gear ratio) to the fourth gear (small gear ratio). The lever 12a is operated. The transmission 12 may be a manual transmission (MT) configured to be able to select one gear from a plurality of gears having different gear ratios.

  The transfer 13 is an auxiliary transmission that distributes the driving force transmitted from the transmission 12 to the front wheel side drive shaft 14F and the rear wheel side drive shaft 14R. The transfer 13 includes two types of gear trains: a high-speed high gear train that transmits the rotational driving force of the transmission 12 without decelerating, and a low-speed low gear train that further decelerates the rotational driving force of the transmission 12. . The driver can selectively use the high gear train and the low gear train by switching the high gear train and the low gear train by operating the shift lever 13a for the transfer 13.

  The transfer 13 includes a differential device (center differential) therein, and absorbs a rotational difference generated between the front wheels and the rear wheels when the vehicle 10 turns.

  The front wheel side drive shaft 14F is connected to the left and right drive shafts 16FL, 16FR via a front differential 15F, and the drive shafts 16FL, 16FR are connected to wheels 17FL, 17FR which are the left and right front wheels, respectively. The rear wheel side drive shaft 14R is connected to the left and right drive shafts 16RL and 16RR via the rear differential 15R, and the left and right rear wheels 17RL and 17RR are connected to the drive shafts 16RL and 16RR, respectively. Yes. In the vehicle 10, the driving torque of the engine 11 is transmitted to the wheels 17FL, 17FR, 17RL, and 17RR through these mechanisms.

  A braking device 300 is provided on each of the wheels 17FL, 17FR, 17RL, and 17RR. The braking device 300 is an example of the “braking means” according to the present invention, and has a mechanism for braking the vehicle 10 by driving a braking member (not shown) according to the hydraulic pressure of the wheel cylinder 300a. Note that the braking device 300 may have any mode as long as the vehicle 10 can be braked, and preferably employs a mode such as a disc brake or a drum brake. The wheels 17FL, 17FR, 17RL and 17RR are provided with wheel speed sensors 410 which will be described later.

  The hydraulic pressure of the hydraulic fluid is transmitted to the wheel cylinder 300a via the master cylinder 19, and the hydraulic pressure in the master cylinder 19 increases and decreases according to the amount of depression of the brake pedal 20 by the driver. It has a configuration. Therefore, the braking force of the braking device 300 is normally controlled by a driver's brake pedal operation. The master cylinder 19 is always supplied with a certain amount of hydraulic fluid from the reservoir tank 21.

  On the other hand, in the hydraulic system of the hydraulic fluid that connects each wheel cylinder 300a and the master cylinder 19, a brake that can increase or decrease the hydraulic pressure in the wheel cylinder 300a separately from the operation of the brake pedal 20 by the driver. An actuator 200 is provided.

  The brake actuator 200 and the braking device 300 constitute a part of the braking control system 1000 that is an example of the “braking control system” according to the present invention, and the operation is performed by the control device 100 that is also a part of the braking control system 1000. It is controlled.

<1-1-2: Configuration of braking control system>
Next, the configuration of the braking control system 1000 will be described with reference to FIG. FIG. 2 is a block diagram of the braking control system 1000. In FIG. 2, the same parts as those in FIG.

  In FIG. 2, the braking control system 1000 includes a control device 100, a brake actuator 200, a braking device 300, a sensor group 400, and an inclinometer 500.

  The control device 100 includes a CPU (Central Processing Unit) 110, a ROM (Read Only Memory) 120, and a RAM 130.

  The CPU 110 is a control unit that controls the operation of the braking control system 1000, and is configured to be able to increase / decrease the braking force of the braking device 300 via the brake actuator 200 in the process of executing a braking control process described later. In addition, each of the “control means”, “target speed setting means”, “trigger position determination means”, and “trigger position detection means” according to the present invention is an example.

  The ROM 120 is a nonvolatile memory in which a braking control program is stored, and the CPU 110 can execute a braking control process by appropriately reading and executing the braking control program. The ROM 120 also stores a reference value used for the braking control process.

  The RAM 130 is a volatile memory configured to be capable of temporarily storing various data generated when the CPU 110 executes the braking control process, and functions as an example of the “storage unit” according to the present invention. It is configured.

  The control device 100 may be configured as a processing unit for executing a braking control process. For example, the control apparatus 100 is at least a part of an unillustrated ECU (Engine Control Unit) that controls the entire operation of the engine 11. It may be configured.

  The sensor group 400 includes a wheel speed sensor 410, a shift position sensor 420, a selected gear train detection sensor 430, a brake pedal sensor 440, an accelerator pedal sensor 450, a driving torque sensor 460, a longitudinal acceleration sensor 470, a start switch 480, and a lateral acceleration sensor 490. Is provided.

  The wheel speed sensor 410 is disposed on each of the wheels 17FL, 17FR, 17RL, and 17RR, and is a sensor that detects the wheel speed based on the rotation of the corresponding wheel. The vehicle speed of the vehicle 10 is specified from the detected wheel speed. The shift position sensor 420 is a sensor that detects the aforementioned shift position of the shift lever 12a. The selected gear train detection sensor 430 is a sensor that detects the shift position of the shift lever 13 a for the transfer 13. The brake pedal sensor 440 is a sensor that detects the amount of depression of the brake pedal 20. The accelerator pedal sensor 450 is a sensor that detects the amount of depression of an accelerator pedal (not shown). The drive torque sensor 460 is a sensor that detects the drive torque output from the engine 11. The longitudinal acceleration sensor 470 is a sensor that detects acceleration in the forward and reverse directions of the vehicle 10 and is used for controlling the braking force of the braking means, and also functions as an example of the “concave / convex detecting means” according to the present invention. It is configured. The activation switch 480 is, for example, a button switch disposed at a position that can be operated by the driver. The activation switch 480 is pressed when the driver desires speed maintenance control to be described later and outputs a predetermined activation input signal. It is configured to be possible. The lateral acceleration sensor 490 is a sensor that detects lateral acceleration of the vehicle 10 and is configured to function as another example of the “concave / convex detection means” according to the present invention.

  The inclinometer 500 is a device that detects the inclination angle of the road surface on which the vehicle 10 travels, and is configured to function as an example of the “inclination angle detecting means” according to the present invention. The tilt angle meter 500 is configured to be able to output an output signal corresponding to the tilt of the liquid level to the control device 100.

<1-1-3: Detailed configuration of brake actuator>
Next, a part of the configuration of the brake actuator 200 will be described with reference to FIG. FIG. 3 is a system diagram of the brake actuator 200. In FIG. 3, the same parts as those in FIG. The brake actuator 200 is a mechanism that can control the hydraulic pressure independently for each braking device 300 in each of the wheels 17FL, 17FR, 17RL, and 17RR. Therefore, in FIG. 2, the configuration of the brake actuator 200 for one wheel is shown, but it is assumed that the other wheels also have the same configuration.

  In FIG. 2, a pipe line 201 is a tubular member that connects the master cylinder 19 and the wheel cylinder 300a and serves as a flow path for hydraulic fluid. A shutoff valve 202 and a holding valve 203 are disposed on the pipe line 201.

  The shutoff valve 202 is an electromagnetic valve whose energization state is controlled by a CPU 110 (not shown in FIG. 2), and is configured to open when not energized and close when energized.

  The holding valve 203 is an electromagnetic valve whose energization state is controlled by the CPU 110, and is configured to open when not energized and close when energized. When the holding valve 203 is closed, the hydraulic system on the wheel cylinder 300a side from the holding valve 203 is closed.

  One end of the pipe 204 is connected between the holding valve 203 and the wheel cylinder 300 a in the pipe 201, and the other end is connected to the reservoir 205. The conduit 204 is provided with a pressure reducing valve 206. The pressure reducing valve 206 is an electromagnetic valve whose current state is controlled by the CPU 110, and is configured to close when not energized and open when energized. The pressure reducing valve 206 is duty-controlled by a drive signal that takes a binary state of energization and non-energization, and is configured to be able to change the communication state of the conduit 204.

  The hydraulic pump 208 that is rotationally driven by the motor 207 functions as a hydraulic pressure source when the CPU 110 controls the braking force. The discharge port of the hydraulic pump 208 is connected between the shutoff valve 202 and the holding valve 203 in the pipe line 201 via the pipe line 209. A check valve 210 that prevents the flow of hydraulic fluid in the direction opposite to the discharge direction is provided on the discharge port side of the hydraulic pump 208.

  On the other hand, the suction port side of the hydraulic pump 208 is connected to the reservoir 205 via a conduit 211, and a check valve 212 that prevents the flow of hydraulic fluid in the direction opposite to the suction direction is connected to the conduit 211. And 213 are arranged.

  In the pipe 211, one end of the pipe 214 is connected between the check valve 212 and the check valve 213, and the other end is connected to the reservoir tank 21. The hydraulic fluid in the reservoir tank 21 is sucked into the hydraulic pump 208 via the pipe line 214. A suction valve 215 that opens and closes the pipe 214 is provided on the pipe 214.

  The suction valve 215 is an electromagnetic valve whose energization state is controlled by the CPU 110, and is configured to close when not energized and open when energized.

<1-2: Operation of Embodiment>
Next, the operation of the braking control system 1000 having the above configuration will be described.

<1-2-1: Control of brake actuator 200>
First, the control of the brake actuator 200 by the CPU 110 will be described with reference to FIG. 2 again.

  The CPU 110 controls energization to the four solenoid valves included in the brake actuator 200, that is, the shutoff valve 202, the holding valve 203, the pressure reducing valve 206, and the suction valve 215, and operates the hydraulic pump 208 as appropriate. The braking force of each braking device 300 is controlled.

  For example, when braking is performed only by depressing the brake pedal 20, the CPU 110 does not energize the valves and does not operate the hydraulic pump 208. In this case, the shutoff valve 202 and the holding valve 203 are opened, and the pressure reducing valve 206 and the suction valve 215 are closed. Accordingly, the flow path of the hydraulic fluid is simply a flow path from the master cylinder 19 to the wheel cylinder 300a, and a change in the hydraulic pressure of the master cylinder 19 according to the amount of depression of the brake pedal 20 is transmitted to each wheel cylinder 300a, so that the vehicle 10 is braked.

  On the other hand, for example, when the braking force of the braking device 300 is decreased regardless of the operation of the brake pedal 20, the CPU 110 energizes the pressure reducing valve 206 to open the pressure reducing valve 206 as appropriate. Thereby, a part of the hydraulic pressure from the master cylinder 19 is released via the pressure reducing valve 206, so that the braking force is reduced. When the braking force of the braking device 300 is increased regardless of the operation of the brake pedal 20, the CPU 110 closes the pressure reducing valve 206, drives the hydraulic pump 208, and stores the hydraulic fluid stored in the reservoir 205. By circulating, the hydraulic pressure of the wheel cylinder 300a is increased. Thereby, the braking force of the braking device 300 increases.

  In this way, the CPU 110 can brake the braking force of the braking device 300 regardless of the amount of depression of the brake pedal 20 by controlling each part of the brake actuator 200. Therefore, according to the braking control system 1000, even when at least some of the wheels 17FL, 17FR, 17RL, and 17RR are locked, it is possible to apply an optimum braking force to each wheel individually. Therefore, the braking control system 1000 is configured to function also as an anti-lock braking system.

<1-2-2: Overview of braking control processing>
The braking control system 1000 is configured to be able to execute a braking control process by the process of the CPU 110. In the process of executing the braking control process, the speed maintenance mode is executed according to the situation.

  The speed maintenance mode is a mode for maintaining the vehicle speed of the vehicle 10 below a target speed set according to the inclination angle when the vehicle 10 descends a slope, for example, and is an example of the speed maintenance control described above. It is. The speed maintenance mode is executed according to a start input signal output to the control device 100 when the driver presses the start switch 480.

  When the speed maintenance mode is executed, the CPU 110 calculates a necessary braking force based on detection values detected by the wheel speed sensor 410, the drive torque sensor 460, and the longitudinal acceleration sensor 470. The CPU 110 increases the braking force of the braking device 300 by driving the hydraulic pump 208 so as to obtain this braking force and increasing the hydraulic pressure in the wheel cylinder 300a via the pipe line 201. At this time, the output of the wheel speed sensor 410 is monitored at fixed clock timings, and when the vehicle speed specified from the wheel speed exceeds the target speed, the CPU 110 controls the vehicle speed to be equal to or lower than the target speed. Control power. Note that when the vehicle 10 is going down a slope, the vehicle speed naturally increases due to the influence of gravity, so that the vehicle speed is ideally maintained at the target speed by executing the speed maintenance mode.

  The speed maintenance mode is executed mainly when descending a slope. In this case, the vehicle 10 can basically descend the slope at a speed equal to or lower than the target speed corresponding to the slope angle of the slope. However, when the slope angle of the slope is too large, if the slope angle is detected when the slope is descending, the control cannot follow the acceleration of the vehicle 10, and the braking force of the braking device 300 needs to be suddenly increased. It might be. This may cause the driver to feel uncomfortable when the speed maintenance mode is executed. Therefore, the braking control system 1000 is configured to be able to set in advance a target speed when descending on a slope, as will be described below.

<1-2-3: Details of braking control processing>
Next, details of the braking control process will be described with reference to FIGS. 4 and 5 as appropriate. FIG. 4 is a flowchart of the braking control process. It is assumed that the braking control process is executed by, for example, reading a braking control program from the ROM 120 by the CPU 110 when the engine 11 is started. FIG. 5 is a schematic diagram of a slope on which the vehicle 10 travels.

  In FIG. 4, it is first determined whether or not the climbing of the slope has started. (Step A10). In the brake control system 1000, the inclination angle of the road surface is always detected by the inclination angle meter 500 at a constant timing. The output value of the inclinometer is output to the control device 100 and is always monitored by the CPU 110. The CPU 110 determines whether or not the vehicle 10 has started climbing on the slope based on a comparison with the climbing start determination threshold stored in the ROM 120. Note that the uphill start determination threshold value is set in advance to an appropriate value experimentally, empirically, or by simulation.

  If the climbing of the slope is not started (step A10: NO), step A10 is repeated until the climbing of the slope is started. When the climbing of the slope is started (step A10: YES), storage of the inclination angle detected by the inclinometer 500 and the acceleration detected by the longitudinal acceleration sensor 470 and the lateral acceleration sensor 490 is started (step A11). ). Note that the position where it is determined that the climbing of the slope is started corresponds to the position A in FIG.

  The inclination angle is stored as inclination angle data representing the absolute value of the inclination angle in association with the position on the slope where the inclination angle is detected. Here, in the present embodiment, the position on the slope is expressed as a relative position with reference to the position A in FIG. Specifically, based on the position A, the CPU 110 calculates the travel distance based on the vehicle speed of the vehicle 10 acquired from the wheel speed detected by the wheel speed sensor 410 and the elapsed time monitored by the CPU 110, for example, The position on the slope is stored as the distance from the position A. If the braking control system 1000 is equipped with a positioning system that measures the absolute position of the vehicle 10, it may be stored as such an absolute position.

  On the other hand, the acceleration is stored in association with the position on the slope like the inclination angle as acceleration data representing the relative magnitude of the acceleration in each of the front-rear direction and the left-right direction. The relative magnitude of the acceleration is determined as one of index values prepared in a plurality of stages according to a preset criterion. This index value represents, for example, that the greater the value, the greater the acceleration. In the present embodiment, this index value is treated as equivalent to a greater slope unevenness level.

  When the uphill slope is started, the CPU 110 determines whether or not the vehicle 10 has stopped (step A12). When the vehicle 10 stops (step A12: YES), the CPU 110 further determines whether or not the shift position of the transmission 12 acquired from the shift position sensor 420 is in the R range (step A20). The R range is a shift position for moving the vehicle 10 backward, and is treated as equivalent to a driver's intention display for moving the vehicle 10 backward. When the shift position is in the R range (step A20: YES), reverse processing is executed. The reverse process will be described later. At this time, whether or not the transfer 13 is in the low gear train may be further determined based on the output value of the selected gear train detection sensor 430. When the transfer 13 is in the low gear train, the driver's intention to carefully descend the slope and go down is clear.

  When the shift position is not in the R range (step A20: NO), the process is returned to step A11 again, and the process up to step A12 is repeated.

  When it is determined that the vehicle 10 has not stopped (step A12: NO), the CPU 110 determines whether or not the slope has ended (step A13).

  Here, the determination as to whether or not the slope has ended is basically made based on the absolute value of the detected inclination angle. In the present embodiment, the determination is made based on whether or not the detected inclination angle is equal to or less than the peak determination threshold value stored in the ROM 120 in advance. For example, the peak determination threshold value may be the same value as the climbing start determination threshold value described above, or may be a different value, but is set as a value smaller than the climbing start determination threshold value.

  However, there may be a landing on the slope that is represented as position B in FIG. If the determination is made simply by comparison with the peak determination threshold value, it may be determined that the slope has ended at the position B, which is not preferable.

  Therefore, when the above-described climbing slope start determination threshold is detected again within a predetermined time, the CPU 110 recognizes the position (for example, the position B in FIG. 5) as a landing and determines that the slope is not finished. (Step A13: NO). The predetermined time is set in advance to an appropriate value experimentally, empirically, or based on simulation.

  This predetermined time may be, for example, the time required to travel a distance that can be determined to be the top, obtained as a calculation result based on the current vehicle speed. If the slope is not finished, the process returns to step A11 and the storage of the inclination angle is continued. Note that the storage of the tilt angle is continued even during the period of the discrimination processing according to step A13.

  When the slope is finished (step A13: YES), the trigger position is determined (step A14). The trigger position is a position that becomes a base point for the CPU 110 to execute the speed maintenance mode when the vehicle 10 descends the slope again. In the present embodiment, it is determined at the top position of the slope, that is, the position C in FIG. As described above, the determination that the vehicle is at the top, that is, the determination that the slope is finished, is made after traveling for a certain time after passing through the trigger position. For example, at position D in FIG. 5, it is recognized that the vehicle 10 is on the top of a slope. Therefore, the CPU 110 searches the position corresponding to the position C in FIG. 5 with reference to the inclination angle data stored in the RAM 130 so as to go back in time from the time point when it is determined in step A13 that the slope has ended. And determined as the trigger position.

  When the trigger position is determined, the CPU 110 sets a target speed for descending the slope (step A15). At this time, the CPU 110 sets the target speed setting target section (target speed setting target section) as a section having the determined trigger position as a base point and the climbing start position on the slope as an end point. In FIG. 5, such a section corresponds to a section from position C to position A.

  The target speed is set to a value corresponding to the slope angle of the slope based on the speed setting map 120a stored in the ROM 120. Here, the speed setting map 120a will be described with reference to FIG. FIG. 6 is a schematic diagram of the speed setting map 120a.

  In FIG. 6, the target speed is given in advance as a standard pattern P in which the target speed is associated with each inclination angle. The standard pattern P is a pattern that is set so that the target speed decreases as the inclination angle increases. It should be noted that the standard pattern P is given an appropriate target speed that the driver does not feel too fast or too slow according to the inclination angle, experimentally, empirically, or by simulation or the like in advance. It is stipulated in.

  Returning to FIG. 4, the CPU 110 refers to the inclination angle data stored in the RAM 130, acquires the target speed corresponding to each inclination angle from the speed setting map 120 a, and the target of the vehicle 10 at the corresponding position on the slope. Set as speed. The set target speed is stored in the RAM 130 in association with the position on the slope. Note that since the tilt angle data stored in the RAM 130 is accumulated in time series from the uphill starting position (position A in FIG. 5) on the slope, this time series is reversed when the target speed is set. Thus, the target speed is set in association with the position having the trigger position as a base point so as to go back on the time axis.

  The target speed is basically set according to the inclination angle of the slope, but if the slope is uneven, the comfort is likely to be lost due to a corresponding physical impact. Therefore, in the present embodiment, the final target speed is set by further correcting the target speed set according to the inclination angle according to the unevenness of the slope.

  When the setting of the target speed according to the inclination angle is completed, the CPU 110 refers to the acceleration data stored in the RAM 130 and acquires the unevenness of the slope in the target speed setting target section for each position on the section. Then, the target speed set according to the inclination angle is corrected according to the above-described unevenness level, that is, the larger the unevenness, the smaller the coefficient. As a result of such correction, the final target speed setting in the target speed setting target section is completed. The finally set target speed is stored in the RAM 130 so as to be overwritten on the target speed set according to the inclination angle.

  Such unevenness of the slope may be indirectly detected by, for example, a roll sensor or a roll angle sensor not shown in FIG. In such a case, the output values of these sensors and the actual unevenness may be associated in advance experimentally, empirically, or by simulation. Alternatively, when the vehicle 10 is equipped with a video processing system including a video camera or an image processing device, the unevenness of the slope is detected using image recognition technology or pattern recognition technology based on the image or video obtained from the video camera. May be. Furthermore, when the vehicle 10 has a positioning system such as a GPS, the shape of the slope may be acquired in advance via these positioning systems.

  When the target speed is set, the CPU 110 determines whether or not there is an activation input (step A16). The activation input is made when the driver operates the activation switch 480 in order to prompt the execution of the speed maintenance mode. For example, the start switch 480 is operated when the driver climbs a slope, turns a certain amount of time at the top, and tries to descend the slope again. When the start switch 480 is operated, a start input signal is output to the control device 100. The CPU 110 monitors the presence / absence of the activation input signal at predetermined time intervals, and determines the presence / absence of the activation input based on the presence / absence of the activation input signal.

  If there is no activation input (step A16: NO), step A16 is repeated until there is an activation input. When there is an activation input (step A16: YES), the CPU 110 determines whether or not a trigger position is detected (step A17).

  CPU 110 searches for the trigger position based on the trigger position information. When the trigger position is determined, the CPU 110 associates the change of the inclination angle with the relative distance from the trigger position and stores it in the RAM 130 as the trigger position information for a certain region that is contiguous with the trigger position. After the activation input is detected, the CPU 110 monitors the transition of the inclination angle detected by the inclinometer 500 and compares it with the transition of the inclination angle defined by the trigger position information to determine whether the trigger position is detected. Is determined.

  If the transition of the tilt angle over the past certain amount from the current position of the vehicle 10 does not coincide with the transition of the tilt angle defined by the trigger information, the CPU 110 continues searching for the trigger position on the assumption that the trigger position is not detected. (Step A17: NO).

  On the other hand, when the transition of the tilt angle matches the transition defined by the trigger information, it is determined that the trigger position has been detected (step A17: YES).

  Note that there is almost no change in the inclination angle in the route from the region corresponding to the top of the slope to the trigger position. Therefore, in this embodiment, in order to avoid erroneous detection, it is detected that the trigger position has been passed when the actual trigger position is passed and a corresponding change in inclination angle is detected within the target speed setting target section, It is determined that the trigger position has been detected.

  When the trigger position is detected, the speed maintenance mode is executed (step A18). In step A18, the output of the wheel speed sensor 410 is monitored, and the CPU 110 appropriately controls the brake actuator 200 so that the vehicle speed does not exceed the speed corresponding to the current position among the preset target speeds. Maintained below target speed.

  When starting execution of the speed maintenance mode, the CPU 110 determines whether or not the target speed setting target section has ended (step A19). The target speed setting target section is a section from the trigger position to the slope uphill starting position, and is a section in which the target speed is set. Therefore, the CPU 110 easily makes such determination based on the distance from the trigger position. It is possible to execute. When the target speed setting target section has not ended (step A19: NO), the downhill of the slope according to the speed maintenance mode is continued. When the target speed setting target section ends (step A19: YES), the process returns to step A10 in preparation for climbing the slope again.

  Here, with reference to FIG. 7, the details of the backward process executed in step A20 will be described. FIG. 7 is a flowchart of the backward process. In the figure, the same reference numerals are assigned to the same parts as those in FIG. 4 and the description thereof is omitted. It should be noted that the reverse processing is effective mainly when it is impossible to climb on the slope and it is necessary to descend on the slope.

  In FIG. 7, first, the presence / absence of an activation input is determined (step A16). If there is no activation input (step A16: NO), the process is suspended until the activation input is detected, and when the activation input is detected (step A16: YES), a target speed for downhill is set (step S16). A15).

  Here, when the target speed is set, a target speed setting target section is set with the current position as the base point and the hill slope starting position as the end point, and the target speed according to the inclination angle and the unevenness of the slope is determined from the current position. Is set in correspondence with the distance (that is, the position in the target speed setting target section). In the braking control process according to the present embodiment, the target speed is set so that the reverse speed is lower than the forward speed when the inclination angle is the same. Specifically, the correction attenuation rate is acquired from the ROM 120, and the target speed is set by multiplying the target speed set according to the inclination angle and the unevenness. Apart from this, the target speed for reverse travel may be set in advance in the speed setting map 120a.

  When the setting of the target speed is completed, the CPU 110 detects the amount of depression of the brake pedal 20 based on the output value of the brake pedal sensor 440, and determines whether or not the braking device 300 has been released (step B11). When the brake device 300 is not released (step B11: NO), the CPU 110 waits until the brake device 300 is released, and when the brake device 300 is released (step B11: YES), the speed maintaining mode is executed (step B11: YES). Step A18). During execution of the speed maintenance mode, it is determined whether or not the target speed setting target section has ended (step A19). If the target speed setting target section has not ended (step A19: NO), the speed maintenance mode continues. At the same time, when the target speed setting target section ends (step A19: YES), the reverse travel processing ends. When the backward process is completed, the process returns to step A10 in FIG.

  As described above, according to the braking control system 1000 according to the present embodiment, the target speed when descending the hill is preset based on the inclination angle detected when climbing the hill. Even if the slope condition of the slope is steep, or even if it is necessary to descend the slope as an unexpected situation, sudden braking does not occur when maintaining the speed. In other words, the speed can be maintained without impairing comfort. Further, since the target speed when descending the slope is appropriately corrected according to the unevenness of the slope, more comfort is ensured than simply setting the target speed according to the inclination angle.

  In the braking control system 1000 according to the present embodiment, the detected inclination angle is stored in the RAM 130 in association with the position on the slope, but the means for storing the inclination angle in this manner is the RAM 130 or the like. It may be a non-volatile storage medium different from the buffer memory. For example, it may be a recording medium such as HD or DVD. In this case, it is only necessary to have a drive device conforming to them. When a relatively large capacity and non-volatile storage means is provided in this way, it becomes possible to store a relatively large amount of tilt angle data relating to the slope on which the vehicle 10 has traveled in the past. Therefore, the convenience is improved as the vehicle 10 continues to travel, which is preferable.

  In the present embodiment, the trigger position is automatically determined according to the slope angle of the slope, but the trigger position may be manually set by, for example, a driver's operation. In this case, since the driver can appropriately operate the operation switch or the like to determine the trigger position, it is preferable because the downhill of the slope reflecting the driver's preference is realized. In addition to the determination of the trigger position or in addition to the determination of the trigger position, detection of the trigger position may be realized by the driver. For example, the effect according to the present invention described above is ensured by storing the trigger position set by the driver himself and performing an input indicating that the trigger is detected at the same position when descending downhill. In addition, when detecting the trigger position manually, it is preferable in that the trigger position can be reliably detected even if the trigger position is not automatically detected by entering the trigger position at an angle different from that when climbing up. is there.

<2: Second Embodiment>
In the first embodiment described above, the target speed is given as a standard pattern P defined in advance according to the inclination angle on the speed setting map 120. However, for example, the driver's sensitivity to speed varies. A value set based on the standard pattern P when descending a slope may be recognized as fast or may be recognized as slow. A second embodiment of the present invention that can cope with such a problem will be described with reference to FIG. FIG. 8 is a schematic diagram of the speed setting map 120b. In the description according to the second embodiment, the same reference numerals are given to the portions overlapping with those in the first embodiment.

  In FIG. 8, a speed setting map 120 b is a map obtained by reading the speed setting map 120 a according to the first embodiment from the ROM 120 and then copying it to the RAM 130. Accordingly, the speed setting map 120b is different from the speed setting map 120a in that it can be rewritten.

  Similar to the speed setting map 120a, the standard pattern P is also set in the speed setting map 120b. However, since this standard pattern P does not reflect the individual sensibility of the driver, the CPU 110 can appropriately rewrite this standard pattern P to generate a unique pattern Pp that is a driver-specific pattern. Has been. That is, the CPU 110 is configured to function as an example of the “map updating unit” according to the present invention.

  Specifically, when the driver accelerates or decelerates by operating the accelerator pedal or the brake pedal 20 while the speed maintenance mode is being executed, it is unique based on the output signal from the accelerator pedal sensor 450 or the brake pedal sensor 440. A pattern Pp is generated.

  For example, when the depression of the brake pedal sensor 440 is detected while the slope at the inclination angle R1 is descending at a target speed V1 set based on a standard pattern in advance, the CPU 110 is acquired from the wheel speed sensor 410. The vehicle speed is correlated with the slope angle of the slope and buffered in the RAM 130 as actually measured vehicle speed data. After the end of the downhill, the CPU 110 refers to the actually measured vehicle speed data that has been buffered, updates the standard pattern P, generates a unique pattern Pp, and stores it in the RAM 130. The unique pattern Pp is, for example, a pattern in which the vehicle speed V1p (V1p <V1) is obtained at the inclination angle R1. When updating the unique pattern Pp, the standard pattern P may or may not be erased. In addition, a plurality of such unique patterns may be generated.

  In addition, when the accelerator pedal is operated and the vehicle 10 accelerates faster than the target speed during the speed maintenance mode, for example, in FIG. 8, the characteristic pattern is unique to a region on the opposite side of the illustrated unique pattern Pp across the standard pattern. Although a pattern is generated, an upper limit pattern Pm is set in advance when updating on the acceleration side. The target speed is not set in an area exceeding the upper limit pattern Pm. For example, at the inclination angle R1, the upper limit value of the target vehicle speed is set to V1m (V1m> V1). Note that the lower limit value of the target vehicle speed is not set in particular, and for example, depending on the driver, it is possible to descend a slope at an extremely low vehicle speed.

  In this way, it is possible to more comfortably descend the slope by reflecting the driver's sensitivity.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and a braking control system with such a change is also applicable. Moreover, it is included in the technical scope of the present invention.

1 is a schematic diagram of a vehicle equipped with a braking control system according to a first embodiment of the present invention. 1 is a schematic diagram of a braking control system according to a first embodiment of the present invention. FIG. 2 is a system diagram of a brake actuator in the vehicle of FIG. 1. It is a flowchart of the braking control process performed in the braking control system of FIG. It is a schematic diagram of the slope where the vehicle of FIG. 1 drive | works. FIG. 5 is a schematic diagram of a speed setting map for setting a target speed in a speed maintenance mode executed in the braking control process of FIG. 4. FIG. 5 is a flowchart of a reverse process executed as part of the braking control process of FIG. 4. FIG. 7 is another schematic diagram of the speed setting map shown in FIG. 6 according to the second embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Vehicle, 20 ... Brake pedal, 100 ... Control device, 110 ... CPU, 120 ... ROM, 120a ... Speed setting map, 120b ... Speed setting map, 130 ... RAM, 200 ... Brake actuator, 300 ... Braking device, 400 ... Sensor group, 500 ... tilt angle meter, 1000 ... braking control system.

Claims (11)

Braking means for braking the vehicle;
An inclination angle detecting means for detecting an inclination angle of a slope on which the vehicle travels;
Storage means for storing the detected inclination angle in association with the position on the slope;
Target speed setting means for presetting a target speed when the vehicle descends the slope based on the stored inclination angle;
A braking control system comprising: control means for controlling the braking means so that the speed of the vehicle is equal to or lower than the preset target speed when the vehicle descends the slope. Trigger position determining means for predetermining a trigger position serving as a base point for controlling the braking means on the slope;
Trigger position detecting means for detecting the trigger position when descending the slope,
The target speed setting means sets the target speed with the trigger position as a base point,
The braking control system according to claim 1, wherein the control unit controls the control unit when the trigger position is detected. The trigger position determination means, when an input for determining the trigger position is performed, determines a position on the slope corresponding to the input as the trigger position. Braking control system. The braking control system according to claim 2 or 3, wherein the trigger position determining means determines the trigger position based on an inclination angle of the slope. The trigger position detection means detects, when the input indicating that the trigger position is detected is performed, the position on the slope corresponding to the input as the trigger position. The braking control system according to any one of the above. The braking control system according to any one of claims 2 to 5, wherein the trigger position detection unit detects the trigger position based on the detected inclination angle. The target speed setting means sets the target speed based on a map in which a value serving as a reference for the target speed is predetermined according to an inclination angle of the slope. The braking control system according to any one of claims. When the speed of the vehicle is changed by operating at least one of an accelerator pedal and a brake pedal during a period when the vehicle is descending the slope at the set target speed, the speed is changed according to the changed speed. The brake control system according to claim 7, further comprising map update means for updating the reference value in the map. The target speed setting means sets a lower speed as the target speed when the vehicle moves backward and descends the slope, compared to a case where the vehicle moves forward and descends the slope. The braking control system according to any one of claims 1 to 8. Further comprising unevenness detecting means for detecting unevenness of the slope,
The storage means stores the detected unevenness in association with a position on the slope,
The braking control system according to any one of claims 1 to 9, wherein the target speed setting means further sets the target speed based on the stored unevenness. The braking control system according to claim 10, wherein the target speed setting unit sets the target speed so that the target speed is relatively decreased as the unevenness is increased.

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