JP2005178531A - Road surface shape detecting device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely estimate a road surface shape from the behavior of a preceding vehicle for preview control of an active suspension device. <P>SOLUTION: A mirror or a number plate of the preceding vehicle are shot by a CCD camera. The behavior of the preceding vehicle is detected from an image produced by shooting, and posture change of an own-vehicle is calculated from a vehicular height value of each wheel position. A position of the CCD camera or an angle change degree on the basis of the posture change is reduced from the image produced by shooting, thereby correcting the behavior of the preceding vehicle. A road surface shape of a part where the preceding vehicle passes is estimated from the corrected behavior of the preceding vehicle. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a road surface shape detection device that detects a road surface shape, and is particularly suitable for estimating a road surface shape based on the behavior of a preceding vehicle.

As such a road surface shape detection device, for example, a preceding vehicle is imaged with a camera, the behavior is image-analyzed to estimate the shape of the road surface, and based on the estimated road surface shape, for example, the suspension characteristics of the host vehicle are determined. There is something to control (for example, Patent Document 1).
JP-A-5-262113

However, the road surface shape detection device described in Patent Document 1 does not take into account changes in the posture of the host vehicle, and thus has a problem that an accurate road surface shape cannot be estimated only from the behavior of the preceding vehicle imaged by the camera. .
The present invention was developed to solve the above problems, and an object of the present invention is to provide a road surface shape detection device capable of estimating an accurate road surface shape by taking into account the posture change of the host vehicle. is there.

  In order to solve the above problems, the road surface shape detection device of the present invention acquires behavior information of a preceding vehicle, detects posture change of the host vehicle, corrects the behavior information of the preceding vehicle, and corrects the corrected preceding vehicle. The road surface shape is estimated based on vehicle behavior information.

  Thus, according to the road surface shape detection device of the present invention, the behavior information of the preceding vehicle is acquired, the attitude change of the host vehicle is detected to correct the behavior information of the preceding vehicle, and the corrected preceding vehicle's behavior information is corrected. Since the road surface shape is estimated based on the behavior information, it is possible to detect the road surface shape accurately by correcting the change in the captured image.

Next, an embodiment of an active suspension device using the road surface shape detection device of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an active suspension device of the present embodiment, in which reference numeral 10 denotes a vehicle body side member, reference numerals 11FL to 11RR denote front left to rear right wheels, and reference numeral 12 denotes an active suspension. Each one is shown.

  The active suspension 12 includes hydraulic cylinders 18FL to 18RR as actuators interposed between the vehicle body side member 10 and the wheel side members 14 of the wheels 11FL to 11RR, and operating pressures of these hydraulic cylinders 18FL to 18RR. Pressure adjusting valves 20FL to 20RR that individually adjust the pressure, and hydraulic oil of a predetermined pressure is supplied to these pressure control valves 20FL to 20RR via the supply side pipe 21S, and the return oil from the pressure control valves 20FL to 20RR is returned. A hydraulic pressure source circuit 22 that recovers through the side pipe 21R, and accumulators 24F and 24R for pressure accumulation interposed in the supply side pipe 21S between the hydraulic pressure source circuit 22 and the pressure control valves 20FL to 20RR, and the vehicle speed is detected. Corresponding to the vehicle speed sensor 26 that outputs a pulse signal corresponding to the vehicle speed and each of the wheels 11FL to 11RR. Vertical acceleration sensors 28FL to 28RR that individually detect the vertical acceleration of the vehicle body at the position, and vehicle height sensors 31FL that detect the wheel-vehicle distance at each wheel position as the vehicle height from the rotation angle of the suspension arm, for example. 31RR, a CCD camera 27 as an imaging means that is mounted in front of the vehicle and captures a front image of the host vehicle, and a distance measuring sensor that is provided in parallel with the CCD camera 27 and detects a distance to an object in front of the host vehicle And a controller 30 for controlling the pressure control valves 20FL to 20RR based on the detection values of the sensors 26 and 28FL to 28RR and the information of the CCD camera 27 and the laser radar 29.

  Each of the hydraulic cylinders 18FL to 18RR has a cylinder tube 18a. In the cylinder tube 18a, a lower pressure chamber L separated by a piston 18c having a through hole in the axial direction is formed. Thrust is generated according to the pressure difference between the upper and lower surfaces and the internal pressure. The lower end of the cylinder tube 18 a is attached to the wheel side member 14, and the upper end of the piston rod 18 b is attached to the vehicle body side member 10. Further, each of the pressure chambers L of the hydraulic cylinders 18FL to 18RR is connected to an output port of the pressure control valves 20FL to 20RR via a hydraulic pipe 38, and is used for absorbing unsprung vibrations via a throttle valve 32. It is connected to the accumulator 34. In addition, a coil spring 36 having a relatively low spring constant and supporting a static load of the vehicle body is disposed between the springs of each of the hydraulic cylinders 18FL to 18RR.

  FIG. 2 shows an operating hydraulic circuit including the hydraulic source circuit 22 and pressure control valves 20FL to 20RR. Each of the pressure control valves 20FL to 20RR includes, for example, a three-port proportional electromagnetic pressure reducing valve having a cylindrical valve housing 20a in which a spool is slidably mounted and a proportional solenoid 20b provided integrally therewith, For example, the hydraulic pressure of each of the hydraulic cylinders 18FL to 18RR can be controlled by adjusting the supply current value i to the proportional solenoid 20b by, for example, voltage duty ratio control. In the figure, reference numeral 20c denotes a check valve for containing the hydraulic pressure of the hydraulic cylinders 18FL to 18RR.

  In addition, return accumulators 50F and 50R for accumulating return hydraulic oil are provided in the common return path of the front left and right pressure control valves 20FL and 20FR and the common return path of the rear left and right pressure control valves 20RL and 20RR, respectively. Return check valves 51F and 51R and switching cocks 52F and 52R are arranged in parallel between the left and right pressure control valves 20FL and 20RR and between the rear left and right pressure control valves 20RL and 20RR, respectively. Filters 53F and 53R are provided in the common supply path for the front left and right pressure control valves 20FL and 20FR and the common supply path for the rear left and right pressure control valves 20RL and 20RR, respectively.

  The hydraulic source circuit 22 includes a drain filter 58 for drain oil from each of the hydraulic cylinders 18FL to 18RR, an oil cooler 59 for cooling the return hydraulic oil, a reservoir tank 60 for storing the hydraulic oil, and pressurized supply of hydraulic oil. A pump 61 for storing pressure, a pump accumulator 62 for accumulating pressurized hydraulic pressure, a relief valve 63 and a line filter 64 interposed in parallel with the supply side pipe 21S, and between the supply side pipe 21S and the return side pipe 21R. A main relief valve 65 interposed between the supply side piping 21S and a flow control valve 67, and a fail valve 68 interposed between the supply side piping 21S and the return side piping 21R. And an operation check valve 69 and a pressure release cock 70 which are interposed in parallel with the return side pipe 21R. It is. Since most of these elements are the same as the sequence circuit, detailed description thereof will be omitted. However, the operation check valve 69 uses the operating oil pressure of each of the hydraulic cylinders 18FL to 18RR as a pilot pressure to operate the system. At the time of shutdown, for example, when the ignition switch is off, the hydraulic pressure of each of the hydraulic cylinders 18FL to 18RR is maintained at a predetermined pressure to maintain the vehicle height in an intermediate state.

  According to this hydraulic circuit, by adjusting the operating hydraulic pressure of each of the hydraulic cylinders 18FL to 18RR, it is possible to expand and contract the distance between the wheel and the vehicle body, and adjust the vehicle body support force at each wheel position. The wheel load of each wheel can be adjusted by combining them. Therefore, for example, as shown in FIG. 3, the hydraulic pressure of the hydraulic cylinders 18FL to 18RR is increased in the concave portion of the road surface to rebound the wheel, or the hydraulic pressure of the hydraulic cylinders 18FL to 18RR is decreased in the convex portion of the road surface. The vehicle body posture can be controlled to be flat, for example, by bouncing the wheels. Further, for example, it is possible to suppress the roll by increasing the hydraulic pressure of the hydraulic cylinders 18FL to 18RR on the turning outer wheel side, or to suppress the pitch by increasing the hydraulic pressure of the hydraulic cylinders 18FL to 18RR on the scut side. is there.

  In the attitude control using such an active suspension device, when the road surface shape is not known in advance, the vertical acceleration sensor 28FL provided at the wheel position is described, for example, in JP-A-2001-47835. The vertical acceleration is detected at ~ 28RR, and as shown in FIG. 4A, a control amount for controlling the vehicle body posture to a predetermined state such as flat is calculated using these as vehicle body posture change inputs from the road surface. This control amount is the working hydraulic pressure of each of the hydraulic cylinders 18FL to 18RR, that is, the command current value i of the pressure control valves 20FL to 20RR, and the output to the vehicle body posture change input. The control amount is calculated by an arithmetic processing device such as a microcomputer in the controller 30.

  On the other hand, when the road surface shape is known in advance, more accurate vehicle body posture control can be performed by outputting a control amount corresponding to the road surface shape. For this purpose, for example, as described in JP-A-2001-47835, sensors for detecting the road surface shape are provided in front of the host vehicle, and the control amount is set according to the road surface shape detected by the sensors. You may make it calculate. However, as shown in FIGS. 4b and 4c, if the road surface shape can be detected or estimated from the behavior of the preceding vehicle of the host vehicle, the calculation of the control amount can be started at an earlier timing. Even if there is a delay in the calculation and processing of the control signal, it is possible to control at a more appropriate timing. The time required for the host vehicle to reach the position of the road surface shape detected from the behavior of the preceding vehicle corresponds to a so-called inter-vehicle time obtained by dividing the inter-vehicle distance between the preceding vehicle and the host vehicle by the traveling speed of the host vehicle.

  Therefore, in the present embodiment, the road surface shape (road surface information) is detected from the behavior of the preceding vehicle by the arithmetic processing of FIG. 5 performed in the controller 30. This calculation process is executed by a timer interrupt process every predetermined sampling time ΔT set to about 10 msec., For example. In this calculation process, first, in step S1, it is determined whether or not a preceding vehicle exists. If there is a preceding vehicle, the process proceeds to step S2, and if not, the process proceeds to step S8. The presence of the preceding vehicle is determined by, for example, recognizing the front object of the host vehicle imaged by the CCD camera 27 as a vehicle by pattern matching or the like, or by detecting the front object of the host vehicle detected by the laser radar 29 at a predetermined speed, for example, It can be detected based on whether or not the vehicle is moving at the same or substantially the same speed as the host vehicle. In addition, as shown in FIG. 4, it may be determined that the preceding vehicle exists only when the preceding vehicle is in an area where the preceding vehicle can be detected (recognized) by the CCD camera 27 or the laser radar 29.

  In step S2, the behavior of the preceding vehicle is detected by analyzing the preceding vehicle captured image in front of the host vehicle imaged by the CCD camera 27, and then the process proceeds to step S3. In the present embodiment, specifically, as shown in FIG. 6, the left and right mirrors ML, MR and license plate (license plate) LP of the preceding vehicle are detected by model matching or the like, and their representative points, for example, The absolute coordinates of the barycentric points of elements and the relative positions of representative points are updated and stored, and if there is a previous update storage content, the behavior of the preceding vehicle is detected by comparison with this time. For example, assuming that the attitude of the host vehicle has not changed, that is, the angle of view of the front image of the host vehicle by the CCD camera 27 has not changed, representatives of the left and right mirrors ML and MR of the preceding vehicle and the license plate LP When all the points are moving downward, the preceding vehicle is bouncing, and when the representative points of the left and right mirrors ML, MR and the license plate LP are all rotating to the right, the preceding vehicle is When the distance between the representative points of the left and right mirrors ML, MR of the preceding vehicle and the representative point of the license plate LP is large, the preceding vehicle pitches to the tail scissor or nose lift side. It is judged that Since the actual behavior of the preceding vehicle should not be as simple as this, it is necessary to determine the size and ratio of the behavior component, such as a bounce component, a roll component, and a pitch component.

  In step S3, the posture change of the host vehicle is calculated based on the vehicle height at each wheel position detected by the vehicle height sensors 31FL to 31RR, and then the process proceeds to step S4. Specifically, for example, when the vehicle height values at all wheel positions are small relative to the vehicle height value indicating a neutral state, the vehicle bounces, and when the vehicle height value on the right wheel side is smaller than the vehicle height value on the left wheel side, The vehicle rolls to the right, and when the vehicle height value on the front wheel side is larger than the vehicle height value on the rear wheel side, it is determined that the host vehicle is pitching toward the tail scut or nose lift. Since the actual behavior of the own vehicle should not be as simple as this, it is necessary to determine the size and ratio of the behavior component, such as a bounce component, a roll component, and a pitch component.

  In step S4, the behavior of the preceding vehicle detected in step S2 is corrected based on the change in posture of the host vehicle calculated in step S3, and then the process proceeds to step S5. Specifically, it is determined how much the position and angle of the CCD camera 27 have changed from the neutral state where there is no change in posture due to the change in posture of the host vehicle calculated in step S3, and the change is detected. The true preceding vehicle behavior component is calculated by subtracting from the preceding preceding behavior component. For example, when the host vehicle bounces, the distance between the representative points of the left and right mirrors ML and MR of the preceding vehicle of the preceding vehicle imaged by the CCD camera 27 and the representative point of the license plate LP is increased ( Therefore, the pitching component of the preceding vehicle is detected largely. Therefore, in such a case, the posture change of the host vehicle (the position change of the CCD camera 27) is calculated from the bounce amount of the host vehicle (more precisely, the bounce amount of the CCD camera 27) and the distance between the preceding vehicle and the host vehicle. ) Is calculated and subtracted from the entire change on the image to correct the pitching component of the preceding vehicle. When the host vehicle pitches, the representative points of the left and right mirrors ML and MR and the license plate LP of the preceding vehicle imaged by the CCD camera 27 simultaneously move upward in the image, so that the bounce component of the preceding vehicle is reduced. It will be detected greatly. Therefore, in such a case, the bounce component of the preceding vehicle is corrected by the pitching amount of the own vehicle (more precisely, the pitching amount of the CCD camera 27). That is, from the vertical position and imaging angle of the CCD camera 27 changed by the pitching of the own vehicle and the inter-vehicle distance between the preceding vehicle and the own vehicle, the attitude change of the own vehicle (the vertical position change of the CCD camera 27 and the imaging angle change). ), The bounce component of the preceding vehicle can be corrected by calculating the amount of change in the attitude of the preceding vehicle on the image and subtracting this from the change in the entire preceding vehicle on the image. The same applies to the roll motion. As for the correction amount of the behavior information of the preceding vehicle, the amount of change on the image when the actual vehicle posture is changed may be obtained and used after being read from the storage table.

  In step S5, after detecting (estimating) the road surface shape of the point where the preceding vehicle passes (hereinafter also simply referred to as the preceding vehicle road surface shape) from the behavior information of the preceding vehicle corrected in step S4, step S6 is performed. Migrate to Specifically, assuming that a vehicle body behavior as shown in FIG. 7b appears for a road shape (road surface fluctuation) as shown in FIG. 7a at a certain traveling speed, for example, by storing the relationship between the two, The road surface shape that best matches the behavior history of the preceding vehicle can be obtained in reverse. The road speed is determined as a parameter for specifying the road surface shape based on the preceding vehicle behavior.

  In step S6, it is determined whether or not the preceding vehicle road surface shape detected (estimated) in step S5 is a road surface shape that can be posture controlled by the active suspension device, and is a road surface shape that can be posture controlled. If so, the process proceeds to step S7. If not, the process proceeds to step S8. Generally, in the active suspension device, the vibration frequency and amplitude of the road surface input (road surface shape) capable of posture control are limited. Therefore, if it is within the posture controllable range, the process proceeds to step S7. The process proceeds to step S8.

In step S7, the preceding vehicle road surface shape detected (estimated) in step S5 is updated and stored, and then the process returns to the main program.
On the other hand, in step S8, the road surface shape of the preceding vehicle is assumed and then the main program is entered.
According to this calculation process, the behavior of the preceding vehicle is detected from the captured image of the preceding vehicle, the attitude change of the own vehicle is calculated from the vehicle height value at each wheel position of the own vehicle, and the CCD camera generated by the attitude change is calculated. The behavior information of the preceding vehicle is corrected from the change in position and angle, and the road surface shape of the point through which the preceding vehicle passes is estimated based on the corrected behavior information of the preceding vehicle. When the estimated preceding vehicle road surface shape is a shape that can be controlled by the active suspension device, the preceding vehicle road surface shape is updated and stored.

  When the preceding vehicle road surface shape is stored in step S7, the hydraulic cylinders 18FL to 18RR are actually driven and the posture is controlled according to the road surface shape. Therefore, there is a time lag until the host vehicle reaches the position of the stored road surface shape. Therefore, in actual posture control, after the preceding vehicle road surface shape is stored in step S7, an inter-vehicle time (time until the host vehicle reaches the position of the stored road surface shape) is calculated, and a timer is calculated. The control is started after waiting for the calculated inter-vehicle time and the timer count to match. In addition, when there is no preceding vehicle road surface shape in step S8, the posture control of the host vehicle is performed based only on the road surface shape detected in step S2.

  As described above, the CCD camera 27, the laser radar 29, and the step S2 of the arithmetic processing in FIG. 5 constitute the preceding vehicle information acquisition means of the road surface shape detecting device of the present invention. Similarly, the vehicle height sensors 31FL to 31RR and Step S3 of the calculation process of FIG. 5 constitutes the own vehicle posture change detection means, step S4 of the calculation process of FIG. Constitutes road surface shape estimating means.

As described above, the road surface shape detection device of the present embodiment detects the behavior of the preceding vehicle, detects the posture change of the own vehicle, corrects the behavior of the preceding vehicle, and based on the corrected behavior information of the preceding vehicle. Since the road surface shape is estimated, it is possible to correct the image captured by the CCD camera and accurately estimate the road surface shape of the portion through which the preceding vehicle passes.
In the above embodiment, the road surface shape detected by the road surface shape detection device of the present invention is used for the preview control of the active suspension device. However, any other road surface shape detected by the road surface shape detection device of the present invention is used. For example, the present invention can be applied to a semi-active suspension device that variably controls a damping force according to road surface input.

Moreover, in the said embodiment, although the CCD camera and the laser radar were used as a preceding vehicle information acquisition means, as a preceding vehicle information acquisition means, the receiver which receives the behavior information transmitted, for example from a preceding vehicle other than this, for example It is also possible to use so-called vehicle-to-vehicle communication. Incidentally, in this inter-vehicle communication, it is desirable to add an identification code for specifying the preceding vehicle.
In the above-described embodiment, the suspension stroke sensor that detects the suspension stroke is used as the own vehicle posture change detecting unit. However, as the own vehicle posture change detecting unit, for example, the vehicle height of the own vehicle is detected. It is also possible to use a vehicle height sensor. As the vehicle height sensor, for example, an ultrasonic device or a laser radar that detects the distance between the vehicle body of the host vehicle and the road surface can be used. By grounding such a vehicle height sensor at, for example, a plurality of locations on the vehicle body, it is possible to detect not only bounce but also various vehicle body posture changes such as roll and pitch.

In the above embodiment, an arithmetic processing unit such as a microcomputer is used as the controller. However, other electronic devices and arithmetic circuits may be used.
Also, when estimating the road surface shape of the passing part of the preceding vehicle from the behavior of the preceding vehicle, taking into account that the behavior varies depending on the type of the preceding vehicle, for example, the magnitude (amplitude) of the behavior of the preceding vehicle and the behavior convergence time, etc. Is used to identify the vehicle type of the preceding vehicle, and based on the identified vehicle type, the behavior information of the preceding vehicle, and the corrected behavior information of the preceding vehicle, the road surface shape of the preceding vehicle passing portion is estimated. Also good.
In order to specify the vehicle type, the size and shape of the vehicle may be detected from an image captured by a CCD camera or the like, thereby specifying the vehicle type.

It is a schematic block diagram which shows one Embodiment of the active suspension apparatus using the road surface shape detection apparatus of this invention. FIG. 2 is a hydraulic circuit diagram of the active suspension device of FIG. 1. It is explanatory drawing of an effect | action of the active suspension apparatus of FIG. It is explanatory drawing of an effect | action of the active suspension apparatus of this embodiment. It is a flowchart which shows the arithmetic processing for the road surface shape detection performed with the controller of FIG. It is explanatory drawing which detects the preceding vehicle performed by the arithmetic processing of FIG. 5, and its behavior. It is explanatory drawing which shows the relationship between a road surface shape and a vehicle body behavior.

Explanation of symbols

11FL to 11RR are wheels 12 is an active suspension device 18FL to 18RR is a hydraulic cylinder 20FL to 20RR is a pressure control valve 22 is a hydraulic power source circuit 27 is a CCD camera 28FL to 28RR is a vertical acceleration sensor 29 is a laser radar 30 is a controller 31FL 31RR is a vehicle height sensor

Claims (8)

  Based on the preceding vehicle information acquisition means for acquiring the behavior information of the preceding vehicle, the own vehicle attitude change detection means for detecting the attitude change of the own vehicle, and the attitude change of the own vehicle detected by the own vehicle attitude change detection means. A preceding vehicle information correcting unit that corrects behavior information of a preceding vehicle acquired by the preceding vehicle information acquiring unit, and a road surface shape that estimates a road surface shape based on the preceding vehicle behavior information corrected by the preceding vehicle information correcting unit. A road surface shape detection apparatus comprising an estimation means.   The road surface shape detection apparatus according to claim 1, wherein the preceding vehicle information acquisition unit includes a CCD camera or a laser radar that images the preceding vehicle.   The road surface shape detection device according to claim 1, wherein the preceding vehicle information acquisition unit is a receiving unit that receives behavior information transmitted from a preceding vehicle.   The road surface shape detection device according to any one of claims 1 to 3, wherein the own vehicle posture change detection means includes a suspension stroke sensor that detects a stroke of the suspension.   The road surface shape detection device according to any one of claims 1 to 3, wherein the own vehicle posture change detection means is constituted by a vehicle height sensor that detects a height of the own vehicle.   The road surface shape detection apparatus according to claim 5, wherein the vehicle height sensor is configured to detect a distance between a vehicle body of the host vehicle and a road surface.   Based on behavior information of the preceding vehicle acquired by the preceding vehicle information acquiring means, the vehicle includes a preceding vehicle vehicle type specifying unit that specifies the vehicle type of the preceding vehicle, and the road surface shape estimating unit is specified by the preceding vehicle vehicle type specifying unit. 7. A road surface shape detecting apparatus according to claim 1, wherein the road surface shape is estimated based on a vehicle type of the preceding vehicle and behavior information of the preceding vehicle corrected by the preceding vehicle information correcting means. .   Acquires behavior information of the preceding vehicle, detects a change in the posture of the host vehicle, corrects the behavior information of the preceding vehicle acquired based on the detected posture change of the host vehicle, and corrects the behavior of the preceding vehicle. A road surface shape detection method characterized by estimating a road surface shape based on information.

Images