JP2005239078A - Rolling prevention device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling prevention device for a vehicle detecting leaving from a ground of a wheel and preventing rolling of the vehicle when the leaving from the ground of the wheel occurs. <P>SOLUTION: The rolling prevention device for the vehicle prevents rolling of the vehicle at turning traveling and has a suspension expansion/contraction amount measurement means for measuring an expansion/contraction amount of the suspension of the vehicle; a roll angle detection means for detecting a roll angle of the vehicle; an inclination angle calculation means for calculating an inclination angle in a vehicle width direction of a front part or a rear part of the vehicle based on the expansion/contraction amount of the suspension measured by the suspension expansion/contraction amount measurement means; a leaving from ground detection means for detecting leaving from the ground of a front wheel or a rear wheel based on the roll angle detected by the roll angle detection means and the inclination angle in the vehicle width direction of the front part or the rear part of the vehicle calculated by the inclination angle calculation means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vehicle rollover prevention device, and more particularly to a vehicle rollover prevention device that detects wheel takeoff to prevent vehicle rollover.

When the vehicle turns, the vehicle may roll over depending on the turning radius determined by the traveling speed and the steering angle. In particular, when a vehicle having a high center of gravity due to a load or the like turns at a high speed, the possibility of overturning increases. Therefore, an invention has been proposed in which the vehicle is decelerated by braking before the vehicle rolls over, or a warning is given to the driver that there is a risk of rollover by an alarm (for example, see Patent Document 1). In this invention, the turning inner wheel of the vehicle that is turning is detected to have rebounded to the full rebound position, and safety measures are taken to prevent rollover.
JP-A-11-170992

  However, in the invention described in Patent Document 1, since the tire lift is detected based on whether one of the turning inner wheels has rebounded to the full rebound position, an increase in the suspension stroke after the tire lift cannot be detected. FIG. 13 is a diagram for explaining a conventional relationship between vehicle height and suspension stroke. FIG. 13A shows a vehicle traveling straight ahead. The vehicle shown in FIG. 13A is in contact with a road surface 15 with a tire 11, and a vehicle body is held by suspensions 13L and 13R connected to the tire side.

  FIG. 13 (b) shows a vehicle that turns to the left and immediately before the left wheel floats on the tire (hereinafter, the tire lift is referred to as a takeoff). By turning to the left, a lateral acceleration G1 in the right direction is applied to the vehicle, and a rolling force is applied to the suspension 13R. Due to the rolling force, the suspension 13R is compressed and shortened to the length L2, and the suspension 13L increases to the length L3. As a result, the right ground distance h2 is shorter than the left ground distance h3. Note that FIG. 13B shows a skimmed state immediately before the left wheel leaves, so the suspension 13R is compressed to the minimum stroke and the suspension 13L is extended to the maximum stroke.

  FIG. 13 (c) shows a vehicle turning to the left, which differs from FIG. 13 (b) in that it receives a lateral acceleration G2 greater than that in FIG. 13 (b). Since the rolling force is larger than that in FIG. 13B, the left wheel is released in FIG. 13C. With the takeoff, the distance to the left is h4. Since the suspension 13R is already compressed to the minimum stroke in the state of FIG. 13B, the length L2 is maintained, and since the suspension 13L is also expanded with the maximum stroke, the length L3 is maintained. On the other hand, with respect to the ground distance, the ground distance on the right side is kept at h2, but the left side has a height h4 (> h3) due to takeoff.

  Therefore, the state shown in FIG. 13 (b) and FIG. 13 (c) cannot be determined by detecting whether or not the wheel has left the ground by detecting that the stroke of the suspension has exceeded a predetermined value. For example, after it is determined that the wheel has taken off, an increase in the suspension stroke cannot be detected, and whether the wheel is floating as shown in FIG. 13C or skimmed as shown in FIG. 13B. It is difficult to determine whether

  In addition, a stabilizer (not shown) that stabilizes the posture of the vehicle acts to reduce the suspension stroke of the turning inner wheel during turning. However, how much the suspension stroke of the inner turning wheel is reduced depends on the degree of the action of the stabilizer. For example, depending on the degree of the action of the stabilizer, the wheel may come off before the suspension 13L reaches the length of L3 as shown in FIG. 13 (b). It is difficult to detect whether or not.

  In view of the above problems, an object of the present invention is to provide a vehicle rollover prevention device that detects the wheel takeoff and prevents the vehicle from rolling over when the wheel takeoff occurs.

  In order to solve the above problems, the present invention provides a vehicle rollover prevention device for preventing the vehicle from rolling over during turning, and includes a suspension expansion / contraction amount measuring means for measuring the amount of expansion / contraction of the suspension of the vehicle, and a roll angle of the vehicle. Roll angle detecting means for detecting the vehicle, inclination angle calculating means for calculating an inclination angle in the vehicle width direction at the front or rear of the vehicle based on the amount of suspension expansion / contraction measured by the suspension expansion / contraction amount measuring means, and roll angle detection means A takeoff detection means for detecting a takeoff of the front wheel or the rear wheel based on the roll angle detected by the vehicle and the inclination angle in the vehicle width direction of the vehicle front or rear calculated by the inclination angle calculation means; It is characterized by having. According to the present invention, the takeoff of the vehicle can be easily detected.

  In one aspect of the present invention, there is provided warning means for warning the driver and automatic braking means for applying braking to the vehicle. If detected, the driver is warned, and the automatic braking means applies braking to the vehicle when the ground detection means detects the front wheel and the rear wheel. According to the present invention, when a wheel takeoff is detected, it is possible to prevent the vehicle from rolling over.

  Further, in one aspect of the present invention, the roll angle detection means calculates the roll angle of the vehicle based on the ground distance measured with the ground distance measurement means provided by two or more ground distance measurement means provided in the width direction of the vehicle. Features. According to the present invention, the roll angle can be detected by using the ground distance measuring means. The ground distance measuring means may measure the variation in the distance to the road surface instead of obtaining the distance to the road surface as an absolute value.

  The present invention also relates to a vehicle rollover prevention device for preventing the vehicle from rolling over during turning, and a suspension expansion / contraction amount measuring means for measuring the amount of suspension expansion / contraction of the vehicle, and a ground distance between the vehicle body and the road surface. Three or more ground distance measuring means for measuring the vehicle height, vehicle body height measuring means for measuring the height of the vehicle body at the front wheel or the rear wheel based on the suspension expansion / contraction amount measured by the suspension expansion / contraction amount measuring means, and the ground distance measurement means Calculated by the plane coordinate calculation means for calculating the coordinates of the plane formed by the ground distance measurement means, and the plane coordinate calculation means Based on the coordinates of the plane formed by the ground distance measuring means and the installation position of the front wheel or rear wheel of the vehicle, the height of the vehicle body at the installation position of the front wheel or rear wheel is determined. Based on the vehicle body height calculating means to be output, the vehicle body height at the front or rear wheel measured by the vehicle body height measuring means, and the vehicle body height at the installation position of the front wheel or rear wheel calculated by the vehicle body height calculating means, There is provided a vehicle rollover prevention device comprising: a ground detection means for detecting a ground separation of a front wheel or a rear wheel.

  According to the present invention, the coordinates of the plane formed by the ground distance measuring means can be calculated, and the height of the vehicle body at the installation position of the front wheel or the rear wheel can be calculated based on the coordinates, so that the takeoff can be detected more accurately. .

  In one embodiment of the present invention, warning means for warning the driver and automatic braking means for applying braking to the vehicle are provided, and the warning means detects the takeoff of either the front wheel or the rear wheel. In this case, the driver is warned, and the automatic braking means applies braking to the vehicle when the takeoff detecting means detects the takeoff of the front wheels and the rear wheels.

  It is possible to provide a vehicle rollover prevention device that detects the wheel takeoff and prevents the vehicle from rolling over when the wheel takeoff occurs.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of a functional configuration diagram of an in-vehicle device provided with a rollover prevention device. The in-vehicle device includes an electronic control unit (hereinafter referred to as ECU) 30 and is controlled by the ECU 30. The roll angle sensor 23 detects the roll angle of the vehicle body, and the detected roll angle is input to the ECU 30 (hereinafter, the roll angle detected by the roll angle sensor 23 is referred to as a detected roll angle). Moreover, the stroke amount of the suspension is input to the ECU 30 from each wheel. The stroke sensor S-FL indicates the stroke amount of the left front wheel, the stroke sensor S-FR indicates the stroke amount of the right front wheel, the stroke sensor S-RL indicates the stroke amount of the left rear wheel, and the stroke sensor S-RR indicates the stroke amount of the right rear wheel. The stroke amount is measured and input to the ECU 30. The ECU 30 determines that the wheel has left the ground based on the detected roll angle and the stroke amount of each wheel.

  A brake actuator 24 and an alarm device 25 are connected to the ECU 30, and braking is applied regardless of the driver's operation and a warning is issued to the driver in a predetermined case as will be described later. Preferably, the G sensor 21 and the vehicle speed sensor 22 are arranged in the in-vehicle device to detect the lateral acceleration and the vehicle speed during turning.

  FIG. 2A shows an example of a schematic perspective view of a traveling vehicle. The vehicle 20 travels on the road surface 15 with four wheels FL, FR, RL, and RR. The vehicle 20 is shown as a rectangular parallelepiped cut out on a predetermined horizontal plane with respect to the road surface, and the vehicle itself is not deformed.

  FIGS. 2B and 2C show the vehicle 20 viewed from the rear in the traveling direction. When the vehicle 20 rolls in the lateral direction G, the roll angle sensor 23 detects the roll angle θ of the vehicle. When the vehicle 20 rolls, the suspension strokes and the suspension lengths Lrr and Lrl change. Note that Lrr is the suspension length of the right rear wheel while traveling straight on a horizontal plane, and Lrr is the suspension length of the left rear wheel. Similarly for the front wheel (not shown), Lfr is the suspension length of the right front wheel, and Lfl is the suspension length of the left front wheel.

  For example, when turning left, Lrr is shortened to Lrr + ΔLrr, and Lrl is increased to Lrl + ΔLrr. ΔLrr represents the stroke amount of the right rear wheel suspension, and ΔLrr represents the stroke amount of the left rear wheel suspension. Similarly, ΔLfr represents the stroke amount of the right front wheel suspension, and ΔLfl represents the stroke amount of the left front wheel suspension.

  Next, the suspension length with corrected tire deflection will be described. The tire is bent by the weight of the vehicle. When the vehicle rolls due to the rolling force, the suspension length on the inner ring side increases and tire deflection is eliminated. Since the stroke sensor is provided in the absorber or the spindle, the change in the stroke amount detected by the stroke sensor does not include the tire deflection amount. For this reason, the suspension length is corrected for the deflection of the tire. In this embodiment, the relationship between the stroke amount and the suspension length in which the tire deflection is corrected is measured, and the suspension length in which the tire deflection is corrected is obtained from the stroke measured by the stroke sensor. Therefore, the suspension length refers to the length of the suspension itself from the ground contact surface of the tire and the road surface.

  FIG. 3 is a graph showing the relationship between the stroke amount measured by the stroke sensor and the suspension length. The ECU 30 holds the relationship between the stroke amount detected by the stroke sensor and the suspension length in advance as shown in the graph of FIG. Thereafter (Examples 1 to 3), the suspension length in which the deflection of the tire is corrected is measured as Lfr or Lfr + ΔLfr.

  The calculation of the vehicle tilt angle will be described. The ECU 30 calculates the tilt angle of the vehicle using the known tread length Tr based on the suspension length. Equation (1) is an equation for calculating the vehicle inclination angle obtained from the suspension length of the front wheel, and Equation (2) is an equation for calculating the vehicle inclination angle obtained from the suspension length of the rear wheel. , Respectively. The front wheel tread length was Trf, and the rear tread length was Trr.

Vehicle tilt angle (front wheel) = arctan {(ΔLfl−ΔLfr) / Trf} (1)
Vehicle tilt angle (rear wheel) = arctan {(ΔLrl−ΔLrr) / Trr} (2)
When the detected roll angle is detected by the roll angle sensor 23 and the vehicle tilt angle is calculated by the equation (1) or (2), the ECU 30 compares the detected roll angle with the vehicle tilt angle. FIG. 4 is a graph for comparing the detected roll angle and the vehicle inclination angle. The horizontal axis in FIG. 4 indicates the horizontal G size, and the vertical axis indicates the detected roll angle and the vehicle tilt angle. As the lateral G increases, the detected roll angle and the vehicle tilt angle increase, but when the lateral G is A, the vehicle tilt angle becomes a constant value. This means that when the lateral G becomes A, the stroke amount does not vary, that is, the wheel has left the ground. The detected roll angle increases with the inclination of the vehicle even after the wheels have taken off. Therefore, the ECU 30 can detect that the wheel has left the ground by detecting that the difference Def1 between the detected roll angle and the vehicle inclination angle is equal to or greater than a predetermined value.

  A process of determining that the wheel has left the ground and preventing the vehicle 30 from rolling over will be described with reference to the flowchart of FIG. This process starts when the vehicle starts running, for example. The ECU 30 receives the roll angle detected by the roll angle sensor 23 and the stroke amount of each wheel from the stroke sensor at predetermined time intervals (steps S101, S102, S103, S104, S105).

  In step S106, the ECU 30 calculates the tilt angle of the vehicle on the front wheel based on equation (1) based on the stroke amount ΔLfr of the right front wheel and the stroke amount ΔLfl of the left front wheel. Similarly, in step S107, the ECU 30 calculates the tilt angle of the vehicle at the rear wheel based on the stroke amount ΔLrr of the right rear wheel and the stroke amount ΔLrr of the left rear wheel based on Expression (2).

  In step S108, the difference between the detected roll angle and the vehicle inclination angle at the front wheels is compared with a preset threshold value. As a result of the comparison, if the threshold value is larger (n in step S108), it is determined that the front wheel is off and the front wheel floating flag is turned on.

  In step S109, the difference between the detected roll angle and the vehicle inclination angle at the rear wheel is compared with a preset threshold value. As a result of the comparison, if the threshold value is larger (n in Step S109), it is determined that the rear wheel is off and the rear wheel floating flag is turned on. Note that the threshold values in steps S108 and S109 need not be the same.

  In step S110, processing is performed based on the number of wheels that have left the ground based on the front wheel floating flag and the rear wheel floating flag. If the front wheel or the rear wheel is off, the alarm device 25 alerts the driver (step S111). When the front wheels and the rear wheels are separated, braking is applied to the vehicle 20 by the brake actuator 24. When braking is applied, it is preferable to use ABS (anti-skid brake system) or TRC (traction control system). When neither the front wheel nor the rear wheel is separated, the process of the flowchart in FIG. 5 is repeated.

  According to the present embodiment, with a simple configuration of the stroke sensor and the roll angle sensor 23, it is possible to detect the wheel takeoff and prevent the vehicle from rolling over based on the detection result.

In Example 1, the detected roll angle detected by the roll angle sensor 23 was compared with the inclination of the vehicle to determine the wheel takeoff. In the second embodiment, a vehicle rollover prevention device that detects the inclination of a vehicle using a ground distance sensor and determines the separation of a wheel will be described.

  FIG. 6A shows an example of a schematic perspective view of a traveling vehicle. In FIG. 6A, the same components as those in FIG. FIG. 6A differs from FIG. 2A in that it has a ground distance sensor 42. As shown in FIG. 6A, at least two ground distance sensors 42 are arranged on the left and right sides of the vehicle. The arrangement position is preferably a position that is perpendicular to the longitudinal direction of the vehicle 20. The ground distance sensor 42 measures the distance to the road surface 42 by transmitting an ultrasonic wave, a laser, or the like and receiving a reflected wave. The ground distance sensor 42 does not measure the absolute value of the distance to the road surface, and may detect a variation in the ground distance.

  FIG.6 (b) shows an example of the function block diagram of the vehicle-mounted apparatus provided with the rollover prevention apparatus. In FIG. 6B, the same components as those in FIG. FIG. 6B is different from FIG. 1 in that it has a ground distance sensor 42. The ground distance measured by the ground distance sensor 42 is input to the ECU 30.

  FIGS. 7A and 7B show the vehicle 20 as seen from the rear in the traveling direction in the second embodiment. 7A and 7B, the same components as those in FIGS. 2B and 2C are denoted by the same reference numerals, and the description thereof is omitted. In the vehicle in FIG. 7A, two ground distance sensors 2 are arranged via a distance W. As shown in FIG. 7A, the distance between the vehicle 20 and the road surface 15 measured by the ground distance sensor 42 arranged on the right side in the traveling direction in a state where the vehicle 20 is traveling straight on a horizontal plane is defined as Bhr. Similarly, the distance between the vehicle 20 and the road surface 15 measured by the ground distance sensor 42 arranged on the left side in the traveling direction is Bhl.

  As shown in FIG. 7B, when the vehicle rolls in the lateral direction G, the suspension strokes, and the total lengths Lrr and Lrl of the suspension vary and the ground distance measured by the ground distance sensor 42 varies. For example, when turning left, the ground distance on the right side of the vehicle is Bhr + ΔBhr, and the ground distance on the left side of the vehicle is Bfl + ΔBhl. ΔBhr represents the amount of change in ground distance on the right side of the vehicle, and ΔBhl represents the amount of change in ground distance on the left side of the vehicle.

  The inclination of the vehicle is calculated by equation (3). Hereinafter, the vehicle inclination calculated by Expression (3) is referred to as vehicle inclination (detected value).

Vehicle inclination (detected value) = (ΔBhl−ΔBhr) / W (3)
The inclination of the vehicle 20 calculated by the variation of the suspension stroke is calculated by the equations (4) and (5) for the front wheels and the rear wheels, respectively.

Vehicle inclination (front wheel) = (ΔLfl−ΔLfr) / Trf Equation (4)
Vehicle tilt (rear wheel) = (ΔLrl−ΔLrr) / Trr (5)
When the vehicle inclination (detected value), the vehicle inclination (front wheel), and the vehicle inclination (rear wheel) are calculated, the ECU 30 detects the vehicle inclination (detected value) and the vehicle inclination (front wheel) or the vehicle inclination (rear). To compare). FIG. 8 is a graph for comparing the vehicle inclination (detected value) with the vehicle inclination (front wheel) or the vehicle inclination (rear wheel). The horizontal axis in FIG. 8 indicates the magnitude of the horizontal G, and the vertical axis indicates the magnitude of the inclination of the vehicle. As the lateral G increases, the vehicle inclination (detection value) increases, but when the lateral G is B, the vehicle inclination (front wheel) or the vehicle inclination (rear wheel) becomes a constant value. This means that when the lateral G becomes B, the stroke amount does not fluctuate, that is, the wheel has left the ground. Therefore, the ECU 30 detects that the difference Def2 between the vehicle inclination (detected value) and the vehicle inclination (front wheel) or the vehicle inclination (rear wheel) is equal to or greater than a predetermined value, and the wheel has left the ground. Can be detected.

  A process for determining that the wheel has left the ground and preventing the vehicle 30 from rolling over will be described with reference to the flowchart of FIG. 9. This process starts when the vehicle starts running, for example. The ECU 30 receives the ground distance and the stroke amount of each wheel from the two ground distance sensors 42 at predetermined time intervals (steps S201, S202, S102, S103, S104, S105).

  In step S203, the inclination (detection value) of the vehicle is calculated by equation (3). Thereby, the inclination of the vehicle body 20 is obtained.

  In step S206, the ECU 30 calculates the inclination of the vehicle in the vicinity of the front wheel according to the equation (4) based on the stroke amount ΔLfr of the right front wheel and the stroke amount ΔLfl of the left front wheel. Similarly, in step S207, the ECU 30 calculates the inclination of the vehicle in the vicinity of the rear wheel based on the stroke amount ΔLrr of the right rear wheel and the stroke amount ΔLrr of the left rear wheel, using equation (5).

  In step S208, the difference between the vehicle inclination (detected value) and the vehicle inclination (front wheel) is compared with a preset threshold value. As a result of the comparison, if the threshold value is larger (n in step S208), it is determined that the front wheel is off and the front wheel floating flag is turned on.

  In step S209, the difference between the vehicle inclination (detected value) and the vehicle inclination (rear wheel) is compared with a preset threshold value. As a result of the comparison, if the threshold value is larger (n in step S209), it is determined that the rear wheel is off and the rear wheel floating flag is turned on. Note that the threshold values in steps S108 and S109 need not be the same.

  Since the process after step S110 is the same as that of the flowchart of FIG. 5, it will be briefly described. That is, when the front wheel or the rear wheel is off, the alarm device 25 alerts the driver (step S111). When the front wheels and the rear wheels are separated, braking is applied to the vehicle 20 by the brake actuator 24. If neither the front wheel nor the rear wheel is off, the process of the flowchart in FIG. 9 is repeated.

  According to the present embodiment, since the vehicle inclination is calculated by the ground distance sensor 42, the vehicle inclination can be detected more accurately than in the first embodiment. The roll angle may be calculated from the vehicle inclination (detected value) and compared with the vehicle inclination angle (front wheel) or (rear wheel) as in the first embodiment.

In Example 3, a vehicle rollover prevention device that detects that a wheel has left the ground by calculating the coordinates of a road surface with respect to the vehicle by a ground distance sensor provided in the vehicle will be described. FIG. 10 shows an example of a schematic perspective view of a traveling vehicle. Since the functional configuration diagram of the vehicle is the same as FIG. 6B, the description thereof is omitted. Also in this embodiment, the suspension length is measured by the stroke sensor.

  The vehicle in FIG. 10 has ground distance sensors 42 at three locations on the bottom surface of the vehicle. The coordinates of each ground distance sensor 42 are S1, S2, and S3 with a predetermined point on the vehicle as the origin. For example, assuming that the width direction of the vehicle is the X axis, the length direction is the Y axis, and the height direction is the Z axis, the coordinates of the ground distance sensor are S1 (x1, y1, z1), S2 (x2, y2, z2), It is represented as S3 (x3, y3, z3). The position of the ground distance sensor 42 is known, and z1 to z3 are ground distances with respect to the road surface measured by the ground distance sensor 42. Expressions (6-1), (6-2), and (6-3) are expressions representing the coordinates of the three ground distance sensors 42.

S1: z1 = ax1 + by1 + c Formula (6-1)
S2: z2 = ax2 + by2 + c Formula (6-2)
S3: z3 = ax3 + by3 + c Formula (6-3)
Since the position of the ground distance sensor 42 is known, a plane including three ground distance sensors can be formed. The coordinates of the plane can be determined based on the values of z1 to z3 that are ground distances. The ECU 20 calculates a, b, and c by simultaneous equations (6-1) based on the position of the ground distance sensor and the ground distances z1 to z3. A, b, and c in the equation (6-1) are constants and change every moment during traveling. By calculating a, b, and c, the coordinates of the plane formed by the three ground distance sensors 42 are determined. If the coordinates of the plane formed by the three ground distance sensors 42 are obtained, the coordinates of a rectangular parallelepiped representing the vehicle 20 having a known shape and size are obtained.

  The coordinates of the vehicle at the position of each wheel are the corners of the vehicle displayed in a rectangular parallelepiped. Zrr) and left rear wheel (Xrl, Yrl, Zrl). Zfr, Zfl, Zrr, Zrl is the height of the vehicle body at the wheel position.

  The coordinates of the vehicle will be described. When the vehicle 20 is tilted by the rolling force, the rectangular parallelepiped is tilted, and the Z coordinate of the vehicle at the wheel position changes. In this embodiment, since a predetermined point in the vehicle is used as the origin, when the vehicle is inclined, it is detected that the road surface is inclined. That is, in this embodiment, assuming that the vehicle is horizontal, the change in the Z coordinate when the vehicle is tilted is calculated as a change in the road surface coordinates (hereinafter referred to as road surface coordinates). Accordingly, the position of the wheel with respect to the predetermined point of the vehicle body (the vehicle body height at the position of each wheel) is represented by the Z coordinate as the distance from the vehicle body to the road surface.

  The Z coordinates Zfr, Zfl, Zrr, Zrl of the wheel position can be obtained as follows. Formula (7-1) etc. is a formula showing the position (Z coordinate) of a wheel displayed by a, b, and c calculated by formula (6-1) etc.

Zfr = aXfr + bYfr + c (7)
Zfl = aXfl + bYfl + c (7-2)
Zrr = aXrr + bYrr + c (7-3)
Zrl = aXrl + bYrl + c (7-4)
Since the Z coordinate is the distance between the vehicle body and the road surface, it can be compared with the vehicle height at the wheel position based on the suspension length measured by the stroke sensor. FIG. 11 is a graph for comparing the Z coordinate and the vehicle height at the wheel position. The horizontal axis in FIG. 11 indicates the size of the horizontal G, and the vertical axis indicates the Z coordinate or the vehicle height at the wheel position. Since the suspension length measured by the stroke sensor is the length of the suspension itself from the contact surface between the tire and the road surface, the suspension length and the vehicle height at the wheel position cannot be directly compared. In the present embodiment, the relationship between the suspension length and the vehicle height of the wheel position (the corner corner of the vehicle 20) is obtained in advance and compared with the Z coordinate calculated by the equation (7-1) or the like.

  According to FIG. 11, as the lateral G increases, the vehicle height at the Z coordinate and the wheel position increases, but when the lateral G is C, the vehicle height at the wheel position becomes a constant value. This means that when the lateral G becomes C, the stroke amount does not vary, that is, the wheel has left the ground. The Z coordinate increases with the inclination of the vehicle even after the wheels have taken off. Therefore, the ECU 30 can detect that the wheel has left the ground by detecting that the difference Def3 between the Z coordinate and the height of the wheel position is equal to or greater than a predetermined value.

  A process of determining that the wheel has left the ground and preventing the vehicle 30 from rolling over will be described with reference to the flowchart of FIG. This process starts when the vehicle starts running, for example. In step S301, the ECU 30 inputs measurement values z1 to z3 from the ground distance sensor 42 at predetermined time intervals. The ECU 30 determines the Z coordinate of each corner of the vehicle 20 based on z1 to z3 as described above.

  In step S302, the stroke amount of each wheel is input from the stroke sensor. The ECU 30 corrects the tire deflection from the stroke amount and calculates the vehicle height at the wheel position.

  In step S303, the ECU 30 compares the Z coordinate of each wheel with the vehicle height at the wheel position. As a result of the comparison, if the difference between the Z coordinate and the vehicle height at the wheel position is larger than a predetermined threshold value (n in step S303), it is determined that the wheel is off. If it is smaller than the predetermined threshold value (y in step S303), the wheel has not left the ground, so the processing in the flowchart is repeated.

  In step S304, the ECU 30 determines whether or not the two wheels have taken off. As a result of the determination, when one wheel is taken off (when the front wheel or the rear wheel is taken off), the alarm device 25 alerts the driver. When the two wheels have taken off (when the front wheels and the rear wheels have taken off), braking is applied to the vehicle 20 by the brake actuator 24.

  In the present embodiment, the height (Z coordinate) of the vehicle body at the wheel position can be calculated by obtaining the road surface coordinates. A traveling vehicle not only rolls in the vehicle width direction but also pitches in the front-rear direction. Since the road surface coordinates are obtained in a form including the influence of pitching, it is possible to provide a vehicle rollover prevention device that accurately detects the takeoff as compared with the height of the wheel position obtained from the stroke sensor.

It is an example of the functional block diagram of the vehicle-mounted apparatus provided with the rollover prevention apparatus. It is an example of the schematic diagram of the vehicle which is drive | working. It is an example of the graph which shows the relationship between the stroke amount measured by the stroke sensor, and suspension length. It is an example of the graph for comparing a detection roll angle and the inclination angle of a vehicle. It is an example of the flowchart figure which shows the process which determines that the wheel left | separated and prevents rollover of a vehicle. It is an example of the schematic perspective view and functional block diagram of the vehicle in Example 2. FIG. It is an example of the schematic diagram of the vehicle seen from the advancing direction back. It is an example of the graph for comparing the inclination (detection value) of a vehicle, and the inclination (front-rear wheel) of a vehicle. It is an example of the flowchart figure which shows the process which determines that the wheel left | separated and prevents rollover of a vehicle. 10 is an example of a schematic perspective view of a vehicle in Embodiment 3. FIG. It is an example of the graph for comparing Z coordinate and the vehicle height of the position of a wheel. It is an example of the flowchart figure which shows the process which determines with the wheel having taken off and prevents rollover of a vehicle. It is a figure for demonstrating the conventional relationship between vehicle height and a suspension stroke.

Explanation of symbols

DESCRIPTION OF SYMBOLS 15 Road surface 20 Vehicle 21 G sensor 22 Vehicle speed sensor 23 Roll angle sensor 24 Brake actuator 25 Alarm device 30 ECU
42 Ground distance sensor S-fl, S-fr, S-rl, S-rr Stroke sensor

Claims (5)

A vehicle rollover prevention device that prevents the vehicle from rolling over during turning,
Suspension expansion / contraction amount measuring means for measuring the expansion / contraction amount of the suspension of the vehicle;
Roll angle detection means for detecting the roll angle of the vehicle;
An inclination angle calculating means for calculating an inclination angle in the vehicle width direction of the vehicle front or rear based on the amount of suspension expansion / contraction measured by the suspension expansion / contraction amount measuring means in the previous period;
Based on the roll angle detected by the roll angle detection means and the inclination angle in the vehicle width direction of the front or rear of the vehicle calculated by the inclination angle calculation means, the separation for detecting the separation of the front wheels or the rear wheels is detected. Ground detection means;
A vehicle rollover prevention device comprising: Warning means for warning the driver, and automatic braking means for braking the vehicle,
The warning means warns a driver when the takeoff detection means detects a takeoff of either a front wheel or a rear wheel,
The automatic braking means applies braking to the vehicle when the takeoff detecting means detects the takeoff of the front wheels and the rear wheels.
The vehicle rollover prevention device according to claim 1. The roll angle detection means calculates a roll angle of the vehicle based on a ground distance with a road surface measured by a ground distance measurement means provided at least two in the width direction of the vehicle.
The vehicle rollover prevention device according to claim 1. A vehicle rollover prevention device that prevents the vehicle from rolling over during turning,
Suspension expansion / contraction amount measuring means for measuring the expansion / contraction amount of the suspension of the vehicle;
Three or more ground distance measuring means for measuring the ground distance between the vehicle body and the road surface;
A vehicle body height measuring means for measuring the height of the vehicle body at the front wheel or the rear wheel based on the suspension expansion / contraction amount measured by the suspension expansion / contraction amount measuring means in the previous period;
A plane coordinate calculating means for calculating the coordinates of the plane formed by the ground distance measuring means based on the ground distance measured by the ground distance measuring means and the installation position where the ground distance measuring means is installed;
A vehicle body that calculates the height of the vehicle body at the installation position of the front wheel or the rear wheel based on the coordinates of the plane formed by the ground distance measurement unit calculated by the plane coordinate calculation unit and the installation position of the front wheel or the rear wheel of the vehicle High calculation means,
Based on the height of the vehicle body at the front or rear wheel measured by the vehicle body height measuring means in the previous period and the height of the vehicle body at the installation position of the front wheel or rear wheel calculated by the vehicle body height calculating means, A takeoff detection means for detecting the ground;
A vehicle rollover prevention device comprising: Warning means for warning the driver, and automatic braking means for braking the vehicle,
The warning means warns a driver when the takeoff detection means detects a takeoff of either a front wheel or a rear wheel,
The automatic braking means applies braking to the vehicle when the takeoff detecting means detects the takeoff of the front wheels and the rear wheels.
The vehicle rollover prevention device according to claim 4.

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