JP2004359203A - Vehicule state monitoring device, and contact ground state quantity acquiring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicule state monitoring device for efficiently monitoring a vehicule state, and a grounding surface state quantity acquiring device capable of efficiently acquiring tire grounding surface information useful for monitoring the vehicule state. <P>SOLUTION: Information on the tire grounding surface 40 at which a tire is actually in contact with a road surface is acquired, and information related to a wheel behavior useful for vehicle traveling control is estimated based on the information. The tire grounding surface information includes the shape of the grounding surface (length l<SB>x</SB>, width, etc.), a ground contact area, ground contact pressure, the distribution of the ground contact pressure, and the like. The estimated wheel behavior-related information includes a lateral force generated at a wheel, a camber angle, a slip angle, and the like. In-vehicle devices such as a steering device and a suspension device are controlled based on the information. A vehicle traveling abnormality state such as the side roll, spin, or the like of the vehicle is detected based on the information, and informed to a driver. The grounding surface information is acquired by measuring displacement in the radial direction at a predetermined position of a tire tread together with the rotation of the wheel, and detecting the ground contact pressure obtained by a piezoelectric element embedded in the tread. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a device for monitoring a state of a vehicle such as a running abnormality of a vehicle based on tire contact surface information, and also relates to a device used for acquiring information of a tire contact surface.
[0002]
[Prior art]
The information from the underbody of the vehicle is effective information for grasping the running state of the vehicle. Until now, as a technique for acquiring information from undercarriage of a vehicle and controlling traveling of the vehicle based on the information, there is a technique described in the following Patent Document, for example.
[0003]
[Patent Document 1]
Japanese Patent Application No. 10-329682
[Patent Document 2]
Japanese Patent Application No. 11-78593
[Patent Document 3]
Japanese Patent Application No. 5-332889
[0004]
Problems to be Solved by the Invention, Means for Solving Problems, and Effects
The technology described in the above-mentioned patent document is to detect a change in wheel load and distortion of a shock absorber using a load sensor and a strain gauge provided in a suspension device, and to detect a squeal noise generated from a tire. It is. In those techniques, the traveling of the vehicle is controlled based on the detection results. However, according to those techniques, for example, there is a problem that an abnormal running state of a vehicle cannot be detected until the behavior of the vehicle has changed to some extent, or that the detection accuracy cannot be sufficiently satisfied. ing.
[0005]
Therefore, based on an idea different from the conventional technology, the present invention efficiently monitors the state of the vehicle and efficiently converts tire contact surface information that is useful information for monitoring the state of the vehicle. The task was to obtain According to the present invention, a vehicle state monitoring device, a contact surface state quantity acquisition device, and the like of the following aspects can be obtained. As in the case of the claims, each aspect is divided into sections, each section is numbered, and the number of another section is cited as necessary. This is for the purpose of facilitating the understanding of the present invention and should not be construed as limiting the technical features and combinations thereof described in the present specification to those described in the following sections. . In addition, when a plurality of items are described in one section, the plurality of items need not always be adopted together. It is also possible to select and adopt only some items.
[0006]
In the following items, (1) corresponds to the claim, (3) to claim 2, (5) to claim 3, (6) to claim 4, ( (7) Claim 5; (8) Claim 6; (9) Claim 7; (10) Claim 8; (11) Claim 9; (13) is Claim 10, (14) is Claim 11, (16) is Claim 12, (17) is Claim 13, (18) is Claim 14, (19) is Claim 15, (20) is Claim 16, (22) is Claim 17, (25) is Claim 18, (27) is Claim 19, Claim 29 corresponds to claim 20, claim 30 corresponds to claim 21, claim 35 corresponds to claim 22, and claim 38 corresponds to claim 23. Also, the term (51) corresponds to claim 24.
[0007]
(1) a contact surface state quantity acquisition unit that acquires a contact surface state quantity that is a state quantity indicating a state of the contact surface on a contact surface that is in contact with the road surface of the tire;
A vehicle state monitoring processing unit that performs a vehicle state monitoring process based on the acquired ground contact surface state quantity;
A vehicle condition monitoring device comprising:
[0008]
The vehicle condition monitoring device of the present invention is a device that monitors the running condition of the vehicle based on information on the ground contact surface where the tire actually contacts the road surface. The vehicle travels by driving, braking, steering, and the like of wheels, and the vehicle receives various forces from the road surface during traveling. Since the tire contact surface is a contact point between the vehicle and the road surface, information on the contact surface accurately and quickly reflects the behavior of the vehicle. Therefore, according to the monitoring device of the present invention, it is possible to efficiently monitor the behavior of the vehicle.
[0009]
(2) The ground plane state quantity acquisition unit determines, as the ground plane state quantity, a shape specifying amount capable of specifying the shape of the ground plane, an area of the ground plane, and a load or surface pressure applied to the ground plane. And (c) acquiring at least one selected from a load distribution or a surface pressure distribution on the ground contact surface.
[0010]
In the monitoring device of the present invention, the ground surface state quantity serving as a basis for monitoring is not particularly limited, but the above-mentioned state quantities are particularly effective as parameters representing the running state of the vehicle. As will be described in detail later, for example, when a vehicle is turning, a lateral force is generated on the wheels, and the shape and area of the contact surface, the load applied to the contact surface, and the state of the contact surface pressure according to the magnitude of the lateral force Etc. change. Also, when the wheels are inclined with respect to the road surface, the above-described shape and the like change according to the camber angle of the wheels. Further, when the vehicle is receiving the lateral G due to turning or the like, a load transfer phenomenon occurs between the inner wheel and the outer wheel, and the above-described shape and the like differ depending on the size of the lateral G to be received. According to the mode described in this section, it is possible to monitor the state of the vehicle based on such a change or difference of the parameter.
[0011]
The specified amount of the shape of the ground plane includes at least one of the length of the ground plane or a part thereof and the width of the ground plane or a part thereof. The length of the contact surface is the length in the direction perpendicular to the rotation axis of the wheel (the circumferential length), and the width of the contact surface is the length in the direction parallel to the rotation axis. In addition, the shape specification amount specifies a shape such as a length of a diagonal line, a ratio of a length and a width of a contact surface, a rate of change of a contact surface length with respect to a position in a width direction, a position of a center of gravity on a figure of the contact surface. Various parameters that can be included. The contact pressure on the contact surface includes an average contact pressure, a maximum contact pressure, and the like, and the contact pressure distribution includes various parameters indicating a relationship between the position on the contact surface and the contact pressure received at the position. This includes, for example, a position where the highest surface pressure is applied, and a surface pressure difference between a plurality of predetermined positions. The above-listed parameters may be values indicating the instantaneous contact state of the ground itself, or values indicating temporal change of the contact surface state. That is, the change amount may be a change amount related to the shape, area, load, surface pressure, or the like of the ground contact surface, or may be a change speed. For example, values such as the amount of increase or decrease in the contact surface pressure and the increase or decrease speed of the contact area can also be the contact state state quantity in this section.
[0012]
(3) The vehicle condition monitoring processing unit includes a traveling abnormal condition detecting unit that detects a traveling abnormal condition, which is an abnormal condition of the traveling of the vehicle, based on the acquired ground contact surface condition quantity. Or the vehicle condition monitoring device according to the above mode (2).
[0013]
The mode described in this section detects a traveling abnormal state of the vehicle based on the acquired information on the ground contact surface. As described above, since the information on the ground contact surface accurately and promptly reflects the behavior of the vehicle, according to this aspect, it is possible to detect an abnormal traveling state early.
[0014]
(4) The traveling abnormal state detecting unit detects the traveling abnormal state as a rollover of the vehicle, an excessive side slip which is an excessive side slip of the vehicle, a steering wheel being taken off, a wheel derailment, a standing wave phenomenon, and a probability of any of them. The vehicle condition monitoring device according to the mode (3), wherein at least one selected from a high condition is detected.
[0015]
The traveling abnormal state that can be detected by the traveling abnormal state detection unit is not particularly limited. However, those exemplified in this section can be appropriately detected from information on the ground contact surface of the tire, and these abnormal states can be detected by the vehicle traveling. According to the mode described in this section, a practical monitoring device is realized because the monitoring device is a general monitoring device that occurs at a certain time. In addition, the excessive side slip referred to here does not mean, for example, a side slip that occurs at the time of normal turning, etc., and a state in which the tire does not grip the road surface, flatly speaking, the vehicle slips in the lateral direction. Means the state of being. Specifically, there are spins, drift-outs, or a state in which the front and rear wheels are largely skidding.
[0016]
(5) The traveling abnormal state detection unit performs the traveling based on at least one of a maximum surface pressure of the contact surface and a degree of deviation in a width direction of the contact pressure distribution as the acquired contact surface state amount. The vehicle state monitoring device according to the above mode (3) or (4), which detects an excessive side slip of the vehicle as an abnormal state or a state in which the vehicle is highly probable.
[0017]
As will be described in detail later, for example, when a large lateral force or cornering force is generated on the wheel during a sharp turn or the like, the center point of the contact load moves on the contact surface in a direction outside the turn, and the surface pressure distribution on the contact surface turns. Bias toward the outside. As the lateral force or the like increases, the maximum surface pressure also increases, and the degree of deviation of the surface pressure distribution in the tire width direction also increases. The mode described in this section is to detect a spin state or the like by using such a change in the state of the contact surface. This aspect is preferably an aspect in which detection is performed based on both the maximum surface pressure and the degree of deviation of the surface pressure distribution.Specifically, for example, the maximum surface pressure exceeds a set threshold pressure. When the location where the maximum surface pressure is reached is outside the center of the tire beyond the threshold position set in the width direction of the tire and is located on the outer side of the tire, a state in which the possibility that an excessive side slip occurs is high is detected. Can be. In a similar manner, when the maximum surface pressure exceeds the set threshold pressure and the range of the contact surface exceeding the threshold pressure is located outside the turning beyond the set position in the width direction, the possibility of excessive skidding is increased. Is determined to be high.
[0018]
(6) The abnormal traveling state detection unit detects a standing wave phenomenon as the abnormal traveling state or a state of high probability thereof based on the length of the ground contact surface as the acquired contact state state quantity. The vehicle condition monitoring device according to the above mode (3) or (4).
[0019]
When the standing wave phenomenon occurs, the tread surface of the tire is wavy, and the length of the ground contact surface in the circumferential direction of the wheel becomes longer. The mode described in this section is a mode in which the state is detected. Specifically, the embodiment can be implemented in such a manner that it is determined that the standing wave phenomenon has occurred when the acquired circumferential length of the contact surface exceeds a set threshold length.
[0020]
(7) The traveling abnormal state detection unit detects the acquired contact surface state quantity and a theoretical contact surface state quantity that is the theoretical contact surface state quantity estimated based on a state in which the vehicle is operated. The vehicle state monitoring device according to the above mode (3) or (4), wherein the abnormal traveling state is detected based on the relationship of (1).
[0021]
For example, when a certain vehicle is in a certain operation state, a theoretical state of the ground contact surface can be estimated from a theoretical traveling model of the vehicle. The mode described in this section detects a traveling abnormal state of the vehicle, for example, by comparing the estimated state of the contact surface with the actually acquired state of the contact surface. More specifically, it is also possible to detect a traveling abnormal state based on a difference between a theoretical state of the ground plane and a state of the actual ground plane in the current vehicle operation state, and also in a virtual limit state. An abnormal traveling state of the vehicle can be detected by comparing the theoretical state of the ground plane with the state of the actual ground plane. By estimating the theoretical ground contact state quantity in accordance with the vehicle model of each individual vehicle, it is possible to detect a traveling abnormal state that is suitable for that vehicle, that is, an actual running abnormality, and a practical monitoring device is realized.
[0022]
The state in which the vehicle is operated, that is, the vehicle operation state does not only mean the operation state of operation members such as an accelerator pedal, a brake pedal, and a steering wheel, but is operated by operating these operation members. It also means the running state of the vehicle in the case where it is performed. More specifically, when the state quantity indicating the vehicle operation state is defined as a vehicle operation state quantity, the vehicle operation state quantity includes an accelerator pedal depression amount, a steering wheel rotation amount (a steering wheel operation angle). : Steering angle in a narrow sense), the vehicle speed, and the angle at which wheels are actually turned off (wheel steering angle: steering angle in a broad sense), and the like.
[0023]
(8) The relationship between the area of the contact surface as the acquired contact surface state quantity and the theoretical contact area which is the area of the contact surface estimated as the theoretical contact surface state quantity, The vehicle condition monitoring device according to the above mode (7), wherein the vehicle abnormality monitoring device detects a derailment or a highly probable condition as the traveling abnormal condition based on the condition.
[0024]
The area of the ground contact surface changes according to the operation state of the vehicle. In a normal running state, the actual contact area of the tire is a theoretical contact area or a contact area close to the theoretical contact area. In the aspect described in this section, for example, if the actual contact area of a tire is reduced to a ratio set to a theoretical contact area or less, the wheels on which the tire is mounted sufficiently cover the road surface. This includes a mode in which it is detected that the vehicle is not being caught, that is, the vehicle is in a state of derailing or a state of high probability of being out.
[0025]
(9) A relationship between the ground contact surface area as the acquired ground contact surface information amount and the theoretical ground contact surface area as the theoretical contact surface state amount estimated as the theoretical ground contact surface state amount. (7) The vehicle condition monitoring device according to the above (7), which detects a rollover of the vehicle or a highly probable state of the vehicle as the traveling abnormal condition based on the speed of decrease of the contact area.
[0026]
For example, when an excessive steering operation such as a sharp turn is performed, the vehicle may roll over. When the vehicle rolls over during turning, the turning inner wheel of the vehicle rises, so that the contact area of the inner ring becomes abnormally small compared to the theoretical contact area. The mode described in this section detects the rollover of the vehicle or the possibility of the rollover based on this phenomenon. Specifically, the aspect described in this section is, for example, one condition that the contact area of the inner ring is smaller than a set ratio with respect to the theoretical contact area, and further, under the condition, the area of the contact surface is When the decrease speed exceeds a set threshold value, it can be determined that rapid steering operation is being performed, and the vehicle is determined to be highly likely to roll over.
[0027]
(10) The traveling abnormal state detection unit may determine, as the acquired contact surface information amount, a portion of the contact surface determined from the center in the width direction of the contact surface and a portion determined toward the vehicle inside. Based on the relationship between the inner and outer surface pressure difference that is the surface pressure difference and the theoretical inner and outer surface pressure difference that is the theoretical inner and outer surface pressure difference estimated as the theoretical ground contact surface state quantity, the vehicle rollover as the vehicle state or its The vehicle condition monitoring device according to the above mode (7), which detects a highly probable condition.
[0028]
As described above, when the vehicle turns, a lateral force is generated on the wheels, and the contact pressure on the outside of the turn with respect to the center of the tire becomes higher than the contact pressure on the inside of the turn. For example, if two portions separated in the width direction with the center of the tire therebetween are set, the theoretical surface pressure difference between the two portions can be estimated according to the operation state of the vehicle according to the vehicle model. . By comparing the theoretical surface pressure difference with the actual surface pressure difference acquired by the two parts, the actual running state can be grasped. The aspect described in this section is, for example, the internal-external surface pressure difference, specifically, a value obtained by subtracting the surface pressure at the position inside the turn from the surface pressure at the position outside the turn of the ground contact surface, the corresponding theoretical internal-external surface pressure difference When the value becomes larger than the value obtained by adding the set margin, a mode in which a large lateral force is generated and it is estimated that there is a possibility of rollover can be adopted. In this section, each of the two portions to be set may be a point, or may be a wide area to some extent.
[0029]
(11) The vehicle state monitoring processing unit includes a wheel behavior-related state quantity estimating unit that estimates a wheel behavior-related state quantity that is a state quantity related to the behavior of the wheel based on the acquired contact surface state quantity ( The vehicle condition monitoring device according to the above mode (1) or (2).
[0030]
The mode described in this section is a mode in which parameters effective for grasping the behavior of the vehicle are estimated from the ground contact surface information. If the information relating to the wheel behavior can be acquired, the state of the vehicle can be estimated based on the information, and can be used for the traveling control of the vehicle.
[0031]
(12) The wheel behavior-related state quantity estimating unit calculates, as the wheel behavior-related state quantity, a coefficient of friction between a road surface and a tire, a slip angle of a wheel, a camber angle of a wheel, a lateral force generated on a wheel, or a cornering force. The vehicle condition monitoring device according to the mode (11), wherein at least one device selected from the following is estimated.
[0032]
The estimated wheel behavior related quantity is not particularly limited, but the ones listed in this section are greatly related to the behavior of the vehicle and are particularly effective information. For example, using a tire testing machine or the like, in advance, in the case of various lateral forces, camber angles, and the like, the contact surface state such as what contact surface shape and contact pressure distribution is to be investigated, If the survey results are held in the form of map data (for example, data including association data between parameters, etc., which is a specific mode as a vehicle model storage means related to the behavior of the related wheels), the Based on the acquired data, the current lateral force, camber angle, and the like of the wheel can be easily estimated from the acquired actual contact surface state. In this specification, the camber angle refers to a camber angle to the ground, that is, a camber angle with respect to a road surface.
[0033]
(13) The wheel behavior-related state quantity estimating unit estimates a load applied to the ground contact surface based on an area of the ground contact surface as the acquired ground surface state amount and a tire air pressure, and Estimating a cornering force generated on a wheel as the wheel behavior-related state quantity based on a shape specifying amount capable of specifying the shape of the ground contact surface as the acquired contact state state quantity, and (11) or (12), wherein a friction coefficient between the road surface and the tire as the wheel behavior-related state quantity is estimated based on the determined load on the ground contact surface and the estimated cornering force. The vehicle condition monitoring device according to claim 1.
[0034]
The mode described in this section is a specific mode for acquiring wheel behavior-related information. By simply detecting the contact area of the tire and the air pressure of the tire during traveling, the contact load applied to the wheel on which the tire is mounted can be easily estimated. Further, as described above, the cornering force is estimated according to the vehicle model, and the road surface μ can be easily estimated from the wheel load and the cornering force. Plainly speaking, this is an embodiment of a new and simple monitoring device that estimates the friction coefficient based on the shape of the ground contact surface of the tire. It should be noted that, as a modification of the present embodiment, the present invention can be implemented in a mode in which only processing for estimating the load is performed, or in a mode in which the cornering force is estimated. Note that, instead of estimating the cornering force, a mode in which the lateral force is estimated may be changed.
[0035]
(14) The traveling abnormal state in which the vehicle state monitoring processing unit detects a traveling abnormal state that is an abnormal state of the vehicle traveling based on the wheel behavior related state quantity estimated by the wheel behavior related state quantity estimating unit. The vehicle condition monitoring device according to the above mode (11) or (12), further comprising a detection unit.
[0036]
The aspect described in this section is different from the above-described aspect in which the traveling abnormality is directly detected from the ground contact surface state quantity, and estimates a parameter relating to wheel behavior from the ground contact surface state, and based on the estimated parameter, the vehicle This is a mode of detecting a traveling abnormal state of the vehicle.
[0037]
(15) The traveling abnormal state detection unit is selected from at least one of a rollover of the vehicle, an excessive side slip of the vehicle, a steering wheel being taken off, a wheel derailment, a standing wave phenomenon, and a state in which any of these is high as the abnormal state. The vehicle condition monitoring device according to the above mode (14), wherein one is detected.
[0038]
Since this section has the same content as the above-mentioned section, detailed description thereof will be omitted.However, since these abnormal states are general ones that occur during vehicle traveling, according to the mode described in this section, Thus, a practical monitoring device can be realized.
[0039]
(16) The wheel behavior-related state quantity estimating section estimates the wheel slip angle as the wheel behavior-related state quantity, and the traveling abnormal state detecting section detects the estimated slip angle and the maximum lateral force. (14) or (15), based on the relationship with the maximum slip angle, which is the theoretical slip angle that can be obtained, detects an excessive side slip of the vehicle as the vehicle state or a state in which the vehicle is highly probable. The vehicle condition monitoring device according to the paragraph.
[0040]
The wheel slip angle is a parameter that appropriately represents the amount of sideslip of the vehicle. Further, the maximum slip angle is a value that is generally determined by the characteristics of the tire. Therefore, based on the relationship between the slip angle and the maximum slip angle, it is possible to accurately determine the limit at which the tire grips the road surface. The aspect described in this section, for example, when the estimated slip angle is larger than the maximum slip angle from the ground contact surface state, it is assumed that the possibility of falling into an excessive skid state such as a spin state is extremely high, and the excessive skid is assumed. Can be detected, and when the slip angle becomes smaller than the maximum slip angle by a set angle, it is also possible to detect that the possibility of occurrence of excessive side slip is high. .
[0041]
(17) The abnormal running state detection unit calculates the estimated wheel behavior-related state quantity and the theoretical wheel behavior-related state quantity that is the theoretical wheel behavior-related state quantity estimated based on the state in which the vehicle is operated. The vehicle state monitoring device according to the above mode (14) or (15), wherein the abnormal state is detected based on a relationship with a state quantity.
[0042]
Similar to the above-described theoretical ground surface state estimation, for example, when a certain vehicle is in an operation state, parameters related to the theoretical wheel behavior are estimated from a theoretical running model of the vehicle. It is possible. The mode described in this section, for example, by comparing the estimated theoretical parameters and parameters related to the current behavior of the wheels estimated from the actually acquired ground contact surface state, etc. This is for detecting a traveling abnormal state. The state in which the vehicle is operated, that is, the vehicle operation state is the same as that described above, and the description is omitted here.
[0043]
(18) The wheel behavior-related state quantity estimating section estimates the lateral force generated on the wheel as the wheel behavior-related state quantity, and the traveling abnormal state detecting section estimates the lateral force as the theoretical wheel behavior-related state quantity. Based on the relationship between the calculated theoretical lateral force and the lateral force estimated by the wheel behavior-related state quantity estimating unit, a state in which the steering wheel is taken as the traveling abnormal state or a state of high probability thereof is detected. The vehicle condition monitoring device according to a certain mode (17).
[0044]
For example, when the vehicle is traveling straight, both the left and right wheels generate little lateral force. However, when one of the steered wheels is affected by the ups and downs of a road surface such as a rut, a large lateral force is generated on one of the steered wheels, and the steering wheel is taken. Even when the vehicle is not on a bad road, even when the vehicle receives a strong crosswind, the wheels may be in a state of generating a lateral force and the steering wheel may be taken. The aspect described in this section compares the theoretical lateral force in the current vehicle operation state with the lateral force estimated from the state of the contact surface of the tire, for example, to determine the relationship in which the difference is set. This is a mode in which it is detected that the handle is taken when it exceeds the limit. More specifically, for example, when the vehicle is traveling straight, since the total theoretical lateral force of the left and right wheels is 0, the total lateral force of the left and right wheels estimated from the contact surface state in the straight traveling state Can be implemented in such a manner as to detect that the steering wheel is taken when the value exceeds a set threshold value. In addition, during turning, it is possible to estimate the total value of the theoretical lateral forces generated on the left and right wheels at the vehicle speed, the steering angle, etc. according to the vehicle model. When the total value of the lateral force estimated from the ground contact surface state for each of the left and right wheels exceeds a certain threshold value with respect to the total value of the theoretical lateral force, it may be implemented in a mode of detecting that the steering wheel is taken. It is possible. Furthermore, if steering is detected, steering can be automatically assisted, such as by performing preload control of the power steering device based on the difference between the theoretical lateral force and the estimated lateral force. It is. When the wheels are affected by the undulation of the road surface, the camber angles of the wheels change. Therefore, it can be considered that the lateral force changes when the camber angle changes. A correlation is established between the camber angle and the lateral force. Therefore, when detecting that the steering wheel is taken, it is also possible to estimate the camber angle from the state of the ground contact surface, estimate the lateral force based on the estimated camber angle, and detect the steering wheel being taken.
[0045]
(19) The vehicle condition monitoring device includes a tire sound detector that detects a tire sound that is a sound generated from the tire, and the traveling abnormal state detector is further detected by the tire sound detector. (3), (4), (7), (14), and (4), based on the generated tire noise, detects an excessive side slip of the vehicle as the traveling abnormal state or a state of high probability of the slip. (15) The vehicle condition monitoring device according to any one of (17) and (17).
[0046]
The tire sound is not the above-described tire contact surface state quantity, but can be an effective parameter representing the tire contact state. When the tire generated sound is loud (for example, when the sound pressure of the tire generated sound is high), it can be estimated that the vehicle is in a so-called slip state. Further, since the so-called squeal sound is a sound that sharply reflects the slip between the tire and the road surface, the slip state can be determined based on the squeal sound. The aspect described in this section detects not only the state of the ground contact surface of the tire described above, but also detects an excessive sideslip of the vehicle based on the state of the sound generated by the tire. Becomes possible. Specifically, for example, when the contact pressure of the tire of the turning inner wheel becomes smaller than a certain threshold value, it is determined that the vehicle is in a sharp turning state, and under that condition, the sound pressure of the squeal sound is set. When the threshold value is exceeded, it is possible to implement the mode in which it is detected that the vehicle is likely to spin or the like.
[0047]
(20) A steering operation determination in which the wheel state monitoring device determines whether or not the operation of the steering device is in an excessive state based on at least a steering operation state amount which is a state amount indicating the operation state of the steering device. (3) to (10), wherein the abnormal traveling state detection unit detects the abnormal traveling state when the steering operation determining unit determines that the steering operation is in an excessive state. The vehicle condition monitoring device according to any one of items (14) to (19).
[0048]
The excessive state referred to in this section is a concept including both a state where the steering operation is excessively large and a state where the steering operation is excessively fast. The abnormal running state of the vehicle is likely to occur when the steering wheel is turned sharply or when the steering wheel is quickly turned. In the mode described in this section, a traveling abnormality is detected in relation to an excessive state of the steering operation, so that a traveling abnormal state caused by the steering operation can be efficiently detected. Note that the abnormal traveling state also depends on the speed of the vehicle. For example, rollover, excessive skidding, and the like are likely to occur when the speed of the vehicle is high. Therefore, the mode described in this section is based on not only the steering operation state but also the speed of the vehicle, and the detection of the abnormal traveling state is performed when the vehicle speed is high and the steering operation is excessive. Can be carried out.
[0049]
(21) The steering operation determining section determines whether or not the steering operation is in an excessive state based on at least one of a steering amount and a steering speed as the steering operation state amount. The vehicle condition monitoring described in the above.
[0050]
The steering operation state quantity is not particularly limited, but the parameters listed in this section are parameters suitable for judging an excessive state. In addition, the steering amount can employ not only the operation amount of the operation member such as the operation angle of the steering wheel, but also the steering angle of the steered wheel. Similarly, the steering speed is not limited to the operation speed of the operation member. Alternatively, the steering angular velocity of the steered wheels may be employed.
[0051]
(22) The vehicle state monitoring device includes an abnormal state notifying section that notifies the driver of an abnormal state detected by the traveling abnormal state detecting section, (3) to (10), and (14) to (14). (21) The vehicle condition monitoring device according to any one of the above (21).
[0052]
According to the aspect described in this section, it is possible to notify the driver of the traveling abnormality of the vehicle. In addition, if the vehicle can be notified in a highly probable state such as rollover or excessive skidding, the driving vehicle itself can stabilize the behavior of the vehicle. The notification means is not particularly limited as long as it appeals to the five senses of the driver, and is not particularly limited. For example, a warning buzzer, an audible notification method such as a sound, a light of an instrument panel, etc. And a visual notification method can be adopted.
[0053]
(23) The vehicle state monitoring processing section performs the vehicle state monitoring processing based on tire characteristic information that is a characteristic of the tire determined depending on the tire. (1) to (22). The vehicle condition monitoring device according to any one of the above.
[0054]
The state of the ground contact surface, the behavior of the wheels, and the like differ depending on the mounted tire, and the limit at which the vehicle falls into a running abnormality also differs depending on the tire. The state of the contact surface differs depending on, for example, geometrical factors such as tire diameter, tread width, and tread pattern, and material and structural factors such as whether the tire is a bias tire or a radial tire. In the aspect described in this section, accurate monitoring is possible because the monitoring processing is performed according to the characteristics of the tires. The above-described maximum slip angle and the like can also be considered as a kind of tire characteristic information. Further, as will be described in detail later, when map data is used in the process of acquiring the contact surface state amount and the process of estimating the vehicle behavior related state amount, the map data can also be considered as a kind of tire characteristic information.
[0055]
(24) The vehicle condition monitoring device further includes a tire characteristic information reading unit that reads the information from a storage medium that is provided integrally with the tire and stores the tire characteristic information by wireless means, and reads the tire characteristic information. The vehicle condition monitoring device according to the mode (23), wherein the vehicle condition monitoring process is performed based on the tire characteristic information read by the unit.
[0056]
The tire characteristic information may be, for example, stored in a storage medium inside a computer of an electronic control unit provided in the vehicle, but as described in this section, the tire itself has a storage medium, and the storage medium If means for storing its own characteristic information and reading out the stored information is provided, it is possible to acquire the characteristic information of the tire every time the tire is mounted by replacing the tire, etc. A monitoring device with excellent performance is realized. For the storage medium described in this section, for example, a wireless tag chip (RFID tag) can be used. The wireless tag is an IC chip having a communication function, and an information transmission method of an electromagnetic induction method, a microwave method, or the like can be used. When a wireless tag is used, an appropriate reading unit may be used according to the transmission method.
[0057]
(25) The vehicle state monitoring device includes a tension estimating unit that estimates a driver's tension, and the vehicle state monitoring processing unit monitors the vehicle state based on the estimated tension. The vehicle condition monitoring apparatus according to any one of the above modes (1) to (24).
[0058]
When the driver's tension is high, smooth operation of the vehicle is not possible, and the vehicle is likely to be in an abnormal running state. In particular, when the steering operation is performed rapidly and the possibility of spin and rollover becomes high, there is a case where an appropriate avoidance operation cannot be performed. Therefore, if the monitoring process according to the tension state is performed as in the mode described in this section, the running state of the vehicle can be stabilized even when the driver is in a tension state. The mode described in this section includes, for example, a mode in which the traveling control is performed by increasing the gain in accordance with the degree of the tension, and a monitoring process (for example, the traveling process) only when the tension exceeds a set threshold. (Abnormal state detection processing). The specific means for detecting the driver's tension is not particularly limited, but can be estimated based on, for example, the heart rate described below, the amount of sweat, the body temperature, and the like.
[0059]
(26) The item (25), wherein the tension estimation unit includes a heart rate detector that detects a driver's heart rate, and estimates the tension based on the detected heart rate. Vehicle condition monitoring device.
[0060]
Since the heart rate is a suitable parameter indicating the degree of tension, it is possible to easily estimate the driver's degree of tension based on the heart rate as in the embodiment described in this section. The heart rate detector may be attached to a part of the driver's body such as an earlobe or the like to measure a heartbeat or the like. The heart rate detector may be provided at a part such as a steering wheel which the driver always contacts, and contacts there. A pulse or the like may be measured at a part of the driver's body.
[0061]
(27) A control unit that controls the monitoring information, which is information relating to at least one of the acquired ground contact surface state quantity and the result obtained by the monitoring processing, using the monitoring information. The vehicle condition monitoring device according to any one of the above modes (1) to (26), including a monitoring information supply unit that supplies the monitoring information to a vehicle-mounted device having:
[0062]
The mode described in this section is a mode in which information on the ground contact surface of the tire, information on the behavior of the wheels estimated based on the information, the running state of the vehicle, and the like can be used for, for example, running control of the vehicle. . Accurate cruise control and quick cruise control can be performed in response to changes in the state of the vehicle.
[0063]
(28) The monitoring information supply unit supplies the monitoring information to at least one selected from a vehicle driving force generation device, a brake device, a steering device, a suspension device, and a transmission device as the vehicle-mounted device. The vehicle condition monitoring device according to the above mode (27).
[0064]
The on-board equipment that uses the ground contact information and the result information of the monitoring process is not particularly limited. However, if such information is used in the equipment listed in this section, effective traveling control can be performed. It becomes. It can be used for various driving controls by supplying it to various on-vehicle devices.Specifically, for example, the steering wheel is likely to be taken to limit the output of the engine when the vehicle is likely to overslip. The control can be such as performing a counter-like steering operation in the event of a collision, hardening the suspension of the turning outer wheel when there is a high possibility of rollover, and applying the brakes early if any of the wheels comes off. is there.
[0065]
(29) The contact surface state quantity acquisition unit includes:
A basic factor amount detector for detecting a basic factor amount which is a physical quantity related to a tread portion of a tire and is a basic factor for obtaining the ground contact surface state quantity, and a basic factor detected by the basic factor quantity detector The vehicle state monitoring device according to any one of (1) to (28), further including a contact surface state quantity acquisition device that acquires the contact surface state amount based on the quantity.
[0066]
For example, when trying to detect the shape of the ground contact surface, it is often difficult to detect it directly. The mode described in this section is a mode in which the value of a parameter relating to the tread portion, which is relatively easy to detect, is detected, and the ground contact surface information is acquired based on the parameter value.
[0067]
(30) The basic factor amount detector includes a tread portion radial displacement detector that detects a radial displacement of a tread portion of a tire as the basic factor amount, and the tread surface state obtaining device includes a tread thereof. The vehicle state monitoring device according to (29), wherein the ground contact surface state quantity is acquired based on the displacement detected by a radial displacement detector.
[0068]
The mode described in this section detects a radial displacement of the tread portion as a parameter relating to the tread portion. If the tire is not grounded, its tread has a cylindrical shape. That is, the distance from the center of the wheel to an arbitrary point in the tread portion is a fixed distance irrespective of the circumferential position. However, when the tire comes into contact with the ground, the tire is deformed, and the distance from the center is smaller in the portion of the ground contact surface than in the portion included in the non-ground contact surface. In the aspect described in this section, utilizing that fact, for example, the distance from the wheel center of a certain place of the tread portion is detected, and based on the distance, whether the place is a place corresponding to the ground contact surface This includes an aspect of detecting whether or not the ground contact information is obtained, and acquiring the ground contact surface information based on the detection result. By detecting the radial displacement of the tread portion, it is possible to detect which area is in contact with the tread portion, and it is possible to acquire the width of the tread, the length of the tread, the shape of the tread, and the like.
[0069]
(31) A tread inner surface position measuring device, wherein the tread portion radial displacement detector is provided on an outer peripheral portion of a rim of a wheel to which a tire is attached, and measures each radial position of an inner surface of the tread portion. A vehicle condition monitoring device according to a certain mode (30).
[0070]
The mode described in this section is a mode in which the distance between the inner surface of the tread portion and the outer periphery of the rim is measured, and the measured value is simulated as the radial displacement of the tread portion. According to the aspect described in this section, since the radial displacement of the tread portion can be detected inside the tire, the detector can be provided outside the wheel.
[0071]
(32) The tread inner surface position measuring device irradiates a measurement wave such as an electromagnetic wave, an ultrasonic wave, or a sound wave to one or more predetermined portions of the inner surface, and uses reflected waves from the predetermined one or more portions. The vehicle condition monitoring apparatus according to (31), wherein a position in the radial direction of one or more positions is measured.
[0072]
The specific means for measuring the distance between the inner surface of the tread portion of the tire and the outer periphery of the rim portion is not particularly limited. As in the mode described in this section, for example, if the distance between the reflected waves is measured based on the time until the reflected waves return, there is an advantage that the structure of the measuring device itself is simplified.
[0073]
(33) The tread portion radial displacement detector detects a radial displacement at each of a plurality of detection points different from each other in a width direction, and the tread portion radial amount acquisition device is configured to detect the tread portion radial direction. From the change in the radial displacement of each of the plurality of detection points due to the rotation of the wheel detected by the displacement detector, the length of the ground contact surface at each of the width-wise positions where each of the plurality of detection points is present (30) The vehicle state monitoring device according to any one of (30) to (32), wherein the vehicle state monitoring amount is acquired as the ground surface state quantity.
[0074]
When acquiring the length of the ground contact surface, that is, the length in the circumferential direction, it is also possible to provide a detection location over the entire circumference and simultaneously detect the radial displacement at the detection location. However, the number of detection devices required is determined by the number of detection devices, which complicates the detector and increases the cost. In the aspect described in this section, for example, the displacement of one detection point in the circumferential direction is detected over a predetermined wheel rotation angle range (for example, one rotation) including the ground contact surface while the wheel is rotating, so that the ground contact surface is detected. Can be detected. There is an advantage that the number of detection points is small and the structure of the detector is simplified.
[0075]
(34) The ground plane state quantity acquisition device acquires the area of the ground plane as the ground plane state quantity based on the length of the ground plane at each of the acquired positions in the width direction. A vehicle condition monitoring device according to a mode (33).
[0076]
The mode described in this section is, for example, when the length at each detection point in the width direction is obtained by the above method, by integrating in the width direction based on the obtained length, the ground contact surface A mode for calculating the area is included. The contact area can be obtained by a simple method.
[0077]
(35) The basic factor amount detector includes an external pressure detector for detecting, as the basic factor amount, an external pressure applied to each of one or more detection points of a tread portion of the tire from outside thereof, and the ground contact surface. The vehicle state monitoring according to any one of paragraphs (29) to (34), wherein the state quantity acquisition device acquires the contact surface state quantity based on the external pressure detected by the external pressure detector. apparatus.
[0078]
The aspect described in this section is different from the aspects described in the above-mentioned series of sections, in that the force received by the tread surface of the tire from the road surface is detected at a set location of the tread surface, thereby relating to the contact surface state of the tire. Information is acquired. In the mode described in this section, specifically, for example, when the external pressure detected at a certain detection point exceeds a set threshold, the point is receiving a force from the road surface, In addition, a mode is included in which the location is determined to be a ground plane, and the length and width of the ground plane, the shape of the ground plane, and the like are acquired from the determination results of the plurality of detected locations. Further, a mode is also included in which the pressure distribution at the plurality of detection points is detected in association with the positions of the points on the ground surface to obtain a load distribution, a pressure distribution, and the like on the ground surface.
[0079]
(36) The external pressure detector is a piezoelectric element-based detector in which each of a plurality of piezoelectric elements embedded in a tread portion of a tire corresponding to each of the one or more detection points is a detection element. 35) The vehicle condition monitoring device according to the above mode.
[0080]
Since the piezoelectric element (piezo element) is relatively small and can be embedded in a tire, the detector can be simplified by embedding it in the tire. Specifically, a detection device that includes a plurality of piezoelectric elements and is formed in a sheet shape (for example, a so-called tactile sensor) can be used. In order to detect the value of the external force applied to the tread surface as accurately as possible, it is desirable that the position where the detection element is embedded be between the tread surface and the belt portion of the tire.
[0081]
(37) A plurality of locations dispersed over the entire surface of the tread portion of the tire are the one or more detection locations, and the external pressure detector detects an external pressure applied to each of the locations. 35. The vehicle condition monitoring device according to any one of the items (35) and (36).
[0082]
According to the aspect described in this section, since the pressure can be detected over the entire surface of the tread portion, for example, by simultaneously detecting a plurality of locations, the length of the ground contact surface at that time can be detected at one time. It is possible to acquire the height, width, shape, etc., and it is also possible to acquire the load distribution and pressure distribution. Note that, although this embodiment is another embodiment, for example, a plurality of points arranged in a line in the width direction are set as detection points, and pressure changes at the respective detection points due to rotation of the wheel are determined by a predetermined value of the tire including the ground contact surface. The length, width, and shape of the ground contact surface, the pressure distribution of the contact surface pressure, and the like can also be acquired by detecting over the rotation angle (for example, one rotation). According to this aspect, it is possible to reduce the number of detection points.
[0083]
(38) The transmission in which the basic factor amount detector is provided on a wheel, and the ground contact surface state acquisition device is provided on the wheel and wirelessly transmits a signal related to a detection value of the basic factor amount detector. The vehicle condition monitoring device according to any one of items (28) to (36), further comprising: a device; and a receiving device provided on the vehicle body to receive the transmitted signal.
[0084]
It is conceivable that a detector for detecting a parameter serving as a basis of the ground surface state quantity is provided on the wheel. However, since the wheels rotate, when a detection signal from the detector is output to the vehicle body side, when using a wired means, it is necessary to perform signal transmission through a slidable contact portion such as a brush, Problems remain in terms of reliability. According to the mode described in this section, since the transmission of information from the wheel side to the vehicle body side does not require such a contact portion, a detector having high reliability in information transmission is obtained. The wheel in this section means a portion rotatably held on the vehicle body, and includes, for example, a tire, a wheel holding the tire, and a hub holding the wheel, for example.
[0085]
(51) A basic factor for obtaining a tread state quantity, which is a physical quantity related to a tread portion of a tire and is a state quantity indicating a state of the tread on a tread that is in contact with a road surface of the tire; A ground plane state quantity characterized by having a basic factor quantity detector for detecting a basic factor quantity, and acquiring the ground plane state quantity based on the basic factor quantity detected by the basic factor quantity detector. Acquisition device.
[0086]
This section relates to an acquisition device for acquiring information relating to a contact surface state, and according to the device, the contact surface information can be acquired efficiently. The contact surface information acquired by the acquisition device is useful information for estimating parameters relating to the behavior of the wheels, detecting an abnormal traveling state of the vehicle, and the like. The description of this section is omitted because it is the same as the above description. Note that the acquisition device described in this section can be implemented in a form that applies the technical features of paragraphs (27) to (37) relating to specific aspects of the acquisition device.
[0087]
(61) A tire characteristic which is provided integrally with a tire, and stores tire characteristic information which is a characteristic of the tire determined depending on the tire, and the information can be read by wireless means. Information storage medium.
(62) A tire provided with the tire characteristic information storage medium.
[0088]
The aspects described in the above two items relate to a storage medium for storing tire characteristic information and a tire provided with the storage medium. The storage medium is, for example, mounted or embedded in a tire, so that when the tire is mounted, characteristic information of the tire can be easily obtained. As described above, the tire characteristic information is useful information for estimating parameters relating to the behavior of the wheels, detecting an abnormal traveling state of the vehicle, and the like. Note that a specific description of the storage medium and the like is the same as the above description, and thus is omitted here.
[0089]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The present invention is by no means limited to the following embodiments. In addition to the following embodiments, the present invention is not limited to the embodiments described in the above section [Problems to be Solved by the Invention, Problem Solving Means and Effects]. Various modifications and improvements can be made based on the knowledge of those skilled in the art.
[0090]
<Contact quantity acquisition device>
First, a description will be given of a contact surface state quantity acquisition device for acquiring contact surface information. The ground plane state quantity acquisition device is a basic factor quantity detector that detects the basic factor quantity that is the basic factor for acquiring the ground plane state quantity, and an object based on the basic factor quantity detected by the basic factor quantity detector. And a contact surface state quantity acquisition processing unit that performs a process for acquiring the contact surface state quantity. The acquisition process may be performed by a processing device mainly composed of a computer. However, when the acquisition process is performed by a vehicle, more specifically, an electronic control unit (ECU) that controls a device mounted on the vehicle, a part of the ECU is included in the above-described processing. It functions as a contact surface state quantity acquisition processing unit. Hereinafter, each of the two basic factor amount detectors having different basic factor amounts to be detected will be described in order.
[0091]
i) Acquisition device with tread radial displacement detector
FIG. 1 shows a configuration of a tread portion radial displacement detector. FIG. 1A is a cross-sectional view of the wheel 10 and the tire 12 cut along a plane perpendicular to the rotation axis of the wheel. FIG. 1B is a cross-sectional view of the wheel 10 and the tire 12 cut along a plane including the rotation axis. FIG. The tread radial displacement detector 14 is a kind of basic factor detector and detects radial displacement of the tread 16 of the tire 12 as a basic factor. The detector 14 includes a plurality of ultrasonic probes 20 as detectors and a detection processing unit 22 to which the plurality of probes 20 are connected. On the vehicle body side, a relay unit 24 for relaying a detection signal from the detection processing unit 22 to the ground surface state acquisition processing unit is provided.
[0092]
The ultrasonic probe 20 is provided on a bracket 28 erected on the outer peripheral portion of the rim 26 of the wheel 10 in a state of being aligned in a line along the width direction of the tire 12. Each probe 20 has a function of irradiating an ultrasonic wave, which is a measurement wave, toward the inner surface of the tread portion 16 of the tire 12, and has a function of receiving a reflected wave of the measurement wave from the inner surface. The detection processing unit 22 performs a detection process for each probe 20. Specifically, each probe 20 and a location on the inner surface of the tread portion 16 corresponding to each probe (a location where a straight line connecting the wheel rotation axis and each probe 20 intersects in a plane perpendicular to the wheel rotation axis). Create a signal according to the distance. In other words, the present detector 14 functions as a tread inner surface position measuring device that measures the radial position of the inner surface of the tread portion 16. The radial position of the inner surface of the tread indicates the radial displacement of the tread portion, and the detection signal is in accordance with the amount of the displacement. The radial displacement of the location is detected. The detection processing unit 22 also functions as a transmission device, and wirelessly transmits the created detection signal. The relay unit 24 functions as a receiving device, and receives the wirelessly transmitted detection signal. The received detection signal is transmitted by the relay unit 24 to an ECU not shown in the figure. Each wheel device is provided with an optical encoder 32 (a resolver, an electromagnetic pickup, or the like) as a rotational position detector for detecting the rotational position of the wheel. Transmitted to the ECU via the
[0093]
In the ECU, that is, the ground contact surface state quantity acquisition processing unit, based on the radial displacement detected by the detector 14, the contact at each of the widthwise positions where the plurality of detection locations of the tread portion 16 is present. The length of the ground 40 is obtained. Assuming that the radial displacement of the tread portion (for example, the displacement of the surface of the tread surface) is z, as can be seen from FIG._sIs the displacement z other than the ground plane 40₀The value becomes smaller. The acquisition processing unit acquires the ground contact surface information using this phenomenon.
[0094]
FIG. 2A shows the result of continuously detecting the displacement z with the rotation of the wheel. In addition, x in the figure shows the position in the circumferential direction of the tread portion 16, and y shows the position in the width direction of the tread portion. In the present detector 14, five detection points B corresponding to each of the probes 20 are set (see FIG. 1B), and one of the detection points B is detected.₀Is located at the center in the width direction of the tire 12, and B₁And B_-1Is B₀Is located at an equal distance from the center in the opposite direction with respect to₂And B_-2Are positioned at the same distance from each other. As shown in FIG. 2A, the displacement z of each of the detection points B caused by the rotation of the wheel is z within a certain range (a range between two broken lines in the figure) in the circumferential position.₀Smaller. FIG. 2B is a projection of a line indicating the displacement in FIG. 2A on the xy plane, and a range surrounded by two broken lines (a hatched portion in the figure) indicates a contact area. It represents the shape of the ground 40.
[0095]
As described above, the rotation angle of the wheel is detected by the encoder 32, and in the acquisition processing unit, based on the change in the detected displacement z accompanying the rotation of the wheel, z <z₀Is calculated, and as a result, the length l of the ground contact surface 40 is calculated._xMore specifically, the length l of the ground contact surface 40 at each of the positions in the width direction where each of the plurality of detection points B exists._x(B_-2) ~ L_x(B₂) Is acquired as the ground surface state quantity. These l_x(B_-2) ~ L_x(B₂) Is a shape specifying amount associated with the width direction position of the ground contact surface 40. Further, in the above-mentioned acquisition processing section, the length l_xAre integrated in the width direction while the complementing process is performed, and as a result, the area of the ground contact surface 40 is obtained as another contact surface state amount. In addition, it is also possible to acquire the position of the center of gravity (the center of gravity on the figure) of the grounding surface 40 by geometric calculation processing as another grounding surface state quantity.
[0096]
In the tread radial displacement detector 14, five detection points are set in the width direction. For example, the number of probes 20 is increased, and the ground contact surface length at more detection points is increased. l_xAnd it is also possible to obtain more detailed contact surface information. Conversely, for example, the ground contact surface length l at the center of the tire in the width direction_xOr the ground contact surface length l at two positions sandwiching the center of the tire 12 in the width direction._xWhen detecting an abnormal state of the vehicle, estimating the behavior of the wheels, or the like is performed only by using only the number of detected points, it is possible to set a small number of detection points corresponding to those positions. Further, in the detector 14, one set of detection points is set at the same circumferential position. However, for example, a plurality of sets of detection points can be set at an equal angular pitch. In the case of the above aspect, the ground contact surface state quantity can be acquired only once for each rotation of the wheel, whereas if a plurality of sets of detection points are set, acquisition can be performed a plurality of times for each rotation of the wheel. Yes, it is possible to quickly detect and estimate a change in the state of the vehicle.
[0097]
ii) Acquisition device with external pressure detector
FIG. 3 shows the configuration of the external pressure detector. FIG. 3A is a partial cross-sectional view of the wheel 10 and the tire 12 cut along a plane including the wheel rotation axis, and FIG. 3B is a diagram illustrating a surface pressure sensor that is a detection device of an external pressure detector. It is. The external pressure detector 50 is a kind of a basic factor amount detector, and is a detector that detects an external pressure applied from the outside to the tread portion 16 of the tire 12 as a basic factor. The detector 50 includes a surface pressure sensor 52 and a detection processing unit 54 to which the surface pressure sensor 52 is connected. Further, on the vehicle body side, a relay unit 24 for relaying a detection signal from the detection processing unit 54 to the ground surface state quantity acquisition processing unit is provided.
[0098]
The surface pressure sensor 52 is a thin sheet in which a plurality of piezoelectric elements 58 each serving as a detection element are arranged in a matrix in one plane, and is also called a tactile sensor. Each of the piezoelectric elements 58 detects a force acting on the same area, and outputs an electric signal corresponding to a force in a direction perpendicular to the sheet surface. The sheet-shaped element portion 60 has substantially the same length as the outer peripheral length of the tire 12 and has a width substantially equal to the width of the tread portion 16 of the tire 12. At a predetermined distance from the outer peripheral surface of the tread portion 16, the tread portion 14 is embedded in the tread portion 14 over the entire circumference and the entire width thereof. With such a structure, the surface pressure sensor 52 can detect a force acting on the outer peripheral surface of the tread portion 16 from the outside toward the center of the wheel over the entire circumference and the entire width of the tread portion 16. It is. The surface pressure sensor 52 has a lead bundle 64 for extracting an electric signal from the piezoelectric element 58, and the lead bundle 64 is connected to the detection processing unit 54.
[0099]
The detection processing unit 54 is attached to a bracket 66 provided on the outer periphery of the rim portion 26 of the wheel 10. The detection processing unit 54 responds to an external force detected by each piezoelectric element 58, and Is created as a detection signal. The detection processing unit 54 also functions as a transmission device, and wirelessly transmits the created detection signal. As in the case of the acquisition device described above, the relay unit 24 functions as a reception device, receives the detection signal transmitted wirelessly, and transmits the received detection signal to the ECU. In this manner, the external pressure detector 50 detects the external force that the tread portion 14 receives. In the ECU, more specifically, in the ground plane state quantity acquisition processing unit of the ECU, arithmetic processing based on the detection result of the detector 50 is performed, and various ground plane state quantities are acquired.
[0100]
FIG. 4 schematically shows the result of detection by the external pressure detector 50. In the figure, the horizontal direction (y direction) indicates the width direction of the tire 12, and the vertical direction (x direction) indicates the circumferential direction of the tire 12. The lines on both sides of the drawing are the limit lines of the detection range in the width direction by the piezoelectric element 58, that is, the lines indicating the width of the tread portion 16, and the points dispersed therein are the detection points K by the piezoelectric element 58, namely, 3 shows a detection position of an external pressure in the tread portion 16. The curve J shown in the figure is an isobar for the detected external pressure. Outermost isobar J₀Is a boundary line (boundary surface boundary line) of whether or not external pressure acts, and is a line indicating the shape of the grounding surface 40. That is, the tire 12 receives the contact pressure in a range within the boundary line. The isobar J is J₁→ J₄, And the pressure at the ground contact surface 40 increases toward the center.
[0101]
From such a detection result, for example, the shape specifying amount of the ground plane 40 including the length and width of the ground plane can be acquired. More specifically, for example, if the interval between the limit lines is calculated at a plurality of positions different from each other in the width direction, similarly to the case of the tread portion radial direction displacement detector 14 described above, each of the plurality of positions in the width direction is calculated. Contact length l_xCan be obtained. Further, as another shape specifying amount, the ground contact area, the graphical center of gravity (center of gravity) O_sCan also be obtained. Since the detector 50 detects surface pressures at various points on the grounding surface, it is necessary to obtain the grounding surface pressure at a specific position set on the grounding surface 40 or a load in a specific range set. Is possible. Also, as the state quantity relating to the surface pressure distribution, the maximum surface pressure P_maxSurface pressure point Q_max, The pressure center of gravity O of the contact surface 40_pIt is also possible to acquire the position of (the center of gravity obtained by weighting with pressure). In addition, the difference between the contact pressure and the contact load at two places with the center in the width direction of the tire 12 interposed therebetween can also be obtained as the state quantity relating to the contact pressure distribution and the load distribution.
[0102]
As another embodiment of the contact surface state quantity acquisition device provided with the present detector 50, similarly to the device provided with the tread portion radial direction detector 14, an encoder for detecting the rotational position of the wheel is provided, and the circumference of each piezoelectric element 58 is provided. By specifying the direction position, it is also possible to acquire a state quantity related to the circumferential position of the ground contact surface 40. Specifically, it is possible to acquire a circumferential displacement of the ground contact surface and the like. In the detector 50, the piezoelectric elements 58 are arranged over the entire surface of the tread portion 16. For example, one or several sets of piezoelectric elements 58 arranged in the width direction at the same circumferential position are arranged. It is also possible to acquire the ground contact surface state amount by continuously detecting an external force that changes due to the rotation of the wheel in a predetermined rotation angle range using the sensor. This mode corresponds to a mode in which the acquisition device including the tread portion radial direction detector 14 is changed to a mode in which the external pressure is detected as a basic factor amount instead of the radial displacement of the tread portion.
[0103]
<Relationship between vehicle running state, wheel state and tread>
The relationship between the contact surface state that can be acquired by the contact surface state acquisition device, the running state of the vehicle, and the behavior state of the wheels will be described.
[0104]
FIG. 5 schematically shows the state of the ground contact surface acquired by the acquisition device including the tread portion radial displacement detector 14, in which the values of the parameters relating to the behavior of the wheels are different. These states can be created, for example, by a tire testing machine such as a flat belt testing machine. FIG. 5A shows a state where no lateral force is generated on the wheels, and a state where the camber angle is 0 ° (not inclined). In other words, this corresponds to a state where the vehicle is traveling straight on a flat road surface. 5 (b) and 5 (c) show a state where a lateral force is generated in the rightward direction in the figure, and FIGS. 5 (d) and 5 (e) show a state in which the wheel is tilted leftward in the figure. Thus, the camber angle is increased.
[0105]
As the generated lateral force increases from FIG. 5 (a) → (b) → (c), the difference between the left and right shapes in the width direction increases. Therefore, from the change in the shape, it is possible to estimate the magnitude of the lateral force generated on the wheel (which can also be referred to as the lateral force generated on the tire). Specifically, for example, the length of the contact surface 40 in a plurality of regions divided in the width direction of the contact surface 40 is obtained in various lateral force states by a test or the like, and the data is obtained in the form of a map or the like. The lateral force is estimated by comparing the stored contact state with the state of the contact surface acquired during actual running. FIGS. 5 (b) and 5 (c) show changes in the shape according to the lateral force. Since the lateral force and the cornering force have a strong correlation, the cornering force generated on the wheels in a similar manner. (Which can also be referred to as the cornering force generated in the tire).
[0106]
As the camber angle increases from FIG. 5 (a) to (d) to (e), the difference between the left and right shapes of the ground contact surface also increases. The difference from the change in the lateral force is that, in this figure, a phenomenon that the width of the ground contact surface 40 is reduced appears. As in the case of the lateral force, data serving as a model is acquired by a test or the like, and the camber angle can be estimated by comparing the data with the actual state of the ground plane 40.
[0107]
FIG. 6 schematically illustrates the state of the ground contact surface acquired by the acquisition device including the external pressure detector 50, in which the wheel slip angle (also referred to as the tire slip angle) is different. FIG. 6A shows a state where the slip angle is 0 °, and FIGS. 6B and 6C show a state where the slip angle increases in that order. FIG. 6C shows a state immediately before the tire loses grip. The feature of the change in the shape of the ground contact surface is similar to that of the above-described lateral force because there is a correlation between the lateral force and the slip angle. Further, as can be seen from the drawing, the pressure distribution is biased to one side in the width direction, and the bias becomes stronger as the slip angle increases. Specifically, the maximum surface pressure P_maxSurface pressure point Q_maxEccentricity from the center in the width direction of the ground contact surface (which may be a centroid or a virtual center in the width direction of the tire) increases, and the maximum surface pressure P_maxAlso increases. If the left and right positions with respect to the center are set as specific positions, the contact pressure difference at those specific positions also increases as the slip angle increases. As described above, it is possible to estimate the values of the parameters related to various wheel behaviors from the contact surface state quantities such as the contact surface pressure, the contact load, and their distribution.
[0108]
The above describes the parameters relating to the behavior of the wheels, that is, the relationship between the wheel behavior-related state quantities and the contact surface state quantities, but the wheel behavior-related state quantities are powerful parameters for judging the abnormal running state of the vehicle. It becomes. For example, if the lateral force, the slip angle, and the like increase, an excessive side slip state such as spin and drift-out tends to occur. Further, as the lateral force and the slip angle increase, the possibility of the vehicle rolling over increases as the vehicle is operated. Therefore, the lateral force and the slip angle are also parameters indicating the ease with which the vehicle rolls over. obtain. Further, when the vehicle rolls over, the camber angle of the wheels increases, so that the camber angle can be a parameter indicating the possibility of rollover. As described above, it is possible to estimate the wheel behavior-related state quantity based on the actually acquired contact surface state quantity, and to detect the abnormal traveling state of the vehicle based on the estimated wheel behavior-related state quantity. It becomes. Further, the lateral force, the slip angle, and the like change depending on the operation state of the vehicle. Specifically, the lateral force and the slip angle change depending on the vehicle speed, the steering angle, and the like, and the shape, area, pressure distribution, and the like of the ground contact surface also change. That is, the operation state of the vehicle, the wheel behavior-related state quantity, and the ground contact state quantity have a correlation with each other. Therefore, it is also possible to directly detect the traveling abnormal state of the vehicle based on the actually acquired contact surface state quantity without estimating the wheel behavior related state quantity.
[0109]
In the actual running state of the vehicle, the state of the ground contact surface of the tire shows a complicated change due to the road surface state, the influence of rolling and pitching of the vehicle body, and the like. Therefore, when estimating parameters related to the behavior of the wheels from the state of the ground contact surface, or when detecting an abnormal running state of the vehicle, a reference is provided in accordance with the purpose of estimation and detection in consideration of the various effects described above, What is necessary is just to follow the reference.
[0110]
<Configuration of vehicle equipped with vehicle condition monitoring device and function of the device>
FIG. 7 schematically shows a hardware configuration of a vehicle equipped with the vehicle condition monitoring device of the present invention, mainly focusing on portions that are deeply related to the present invention. Various detectors and sensors are provided in various parts of the vehicle. More specifically, each of the four wheels 70FR, 70FL, 70RR, and 70RL (hereinafter, may be collectively referred to as "wheels 70") has a base for detecting the basic factor amount I described above. A factor amount detector 72 is provided. In the present vehicle, the basic factor amount detector 72 is configured to include both the tread radial displacement detector 14 and the external pressure detector 50 for the sake of convenience in the description below. In addition, it is also possible to implement in the aspect provided with any one detector.
[0111]
The vehicle is provided with a wheel rotation angle sensor 74 for each wheel 70. The wheel rotation angle sensor 74 includes the encoder 32, the relay unit 24, and the like described above, and detects the wheel rotation angle θ. In addition, the wheel rotation angle sensor 74 also functions as a wheel speed detector in ABS control of a brake and the like. Further, for each wheel 70, a tire sound detector 76 for detecting a tire sound N generated from the mounted tire 12 is provided. The tire sound detector 76 includes a microphone, an amplifier, a filter, and the like. In addition, a steering angle sensor 80 for detecting an operation angle φ (a steering angle in a narrow sense, which is a kind of steering operation state amount) which is a rotation angle of the steering wheel 78, a detection device attached to the driver's ear , A heart rate detector 82 for detecting a driver's heart rate H, a lateral G sensor 84 for detecting a lateral acceleration G of the vehicle, and the like. Further, a tag chip 86 as a storage medium for storing tire characteristic information T, which is information on characteristics of the tire 12, is attached to the inner surface of each tire 12 mounted on each wheel 70 (FIG. 3). The tag chip 86 has a function of transmitting the stored information by microwave. Each wheel 70 has a tire pressure P on the wheel 10._airIs provided (see FIG. 1). This air pressure sensor 88 also has an information transmission function. The relay unit 24 has a function as a receiving device for the information, and includes the tire characteristic information T and the tire pressure P._airIs output along the same path as the basic factor amount I. The detectors and sensors listed here have a well-known structure, and a detailed description thereof will be omitted.
[0112]
The vehicle is provided with an electronic control unit (ECU) 90 for controlling various onboard devices. The ECU 90 mainly includes a computer 102 including a CPU 92, a ROM 94, a RAM 96, an input / output interface (I / O) 98, and an internal bus 100 for connecting them. The above various detectors, sensors, and the like are connected to the I / O 98. Further, the ECU 90 controls on-vehicle devices such as an engine device 110, a brake device 112, a steering device 114, a transmission device 116, and a suspension device 118, which are a kind of vehicle driving force generating device. The ECU 90 includes a driver 120 that is a drive circuit of each of the vehicle-mounted devices. Each of the vehicle-mounted devices is connected to the I / O 98 via each of the drivers 120. The vehicle is provided with a notification device 122, and the notification device 122 is provided. The driver is notified of the abnormal traveling state of the vehicle. The notification device 122 includes a warning light, a warning buzzer, and the like provided on the instrument panel. In the present vehicle, all of the above-listed on-vehicle devices are electronically controlled, but any of them may be devices that are not electronically controlled. Further, in this vehicle, all of the above-listed vehicle-mounted devices are controlled by one ECU 90, but one or more of these vehicle-mounted devices are controlled by a separately provided ECU. May be adopted. In that case, the ECU 90 may be connected to another ECU by a communication unit.
[0113]
The vehicle condition monitoring device includes the above-described detectors and sensors, such as the basic factor amount detector 72, and the ECU 90 plays a central part thereof. In other words, the ECU 90 performs the process of estimating the wheel behavior-related state quantity and detecting the abnormal state of the vehicle running, and a part of the ECU 90 is a component of the vehicle state monitoring device. In the present vehicle, for convenience of explanation, the ECU 90 also serves as a control unit of each vehicle-mounted device. Therefore, the ECU 90 that controls the vehicle-mounted device performs a vehicle state monitoring process. However, in place of this embodiment, it is also possible to carry out the above-described estimation and detection process by a computer different from the vehicle-mounted device.
[0114]
FIG. 8 is a functional block diagram of the vehicle condition monitoring device, more specifically, a functional block diagram focusing on the functions of the ECU 90 as a part of the vehicle condition monitoring device. The broken line in the figure indicates the boundary of the ECU 90, and the functional blocks present inside the broken line represent the ECU 90 that performs various processes as components of the ECU 90. It should be noted that the details of the specific processing in each functional part will be described in detail later, so that the description here will be simplified.
[0115]
The contact surface information acquisition processing unit 130 performs a process of acquiring the contact surface state quantity based on the basis factor amount I from the basis factor amount detector 72. The ground plane information acquisition processing unit 130 and the basic factor amount detector 72 constitute a ground plane state quantity acquisition device, that is, a ground plane state quantity acquisition unit. The vehicle state monitoring processing unit 132 includes a wheel behavior state amount estimating unit 134 and a traveling abnormal state detecting unit 136, and performs monitoring processing based on the acquired ground surface state amount. The wheel behavior state quantity estimation unit 134 estimates a wheel behavior-related state quantity based on the acquired contact surface state quantity. The traveling state abnormality detection unit 136 detects a traveling abnormality state of the vehicle based on the acquired contact state state quantity, estimated wheel behavior-related state quantity, and the like. The monitoring information supply unit 138 supplies monitoring information, which is information relating to at least one of the acquired ground contact surface state quantity and the result obtained by the monitoring processing, to the vehicle-mounted device. Specifically, it is supplied to the control unit of the vehicle-mounted device. In the present vehicle, the control of the on-vehicle device is also performed by the ECU, so the supply process is a process inside the ECU 90. The abnormal state notification processing unit 140 configures an abnormal state notification unit with the notification device 122, and the abnormal state notification unit 140 notifies the driver of the detected abnormal state.
[0116]
The vehicle operation state amount acquisition processing unit 142 calculates the wheel rotation angle θ, the operation angle φ, the vehicle lateral acceleration G, and the like, which are operation state amounts detected by the wheel rotation angle sensor 74, the steering angle sensor 80, the lateral G sensor 84, and the like. It receives and, if necessary, performs a process of acquiring another operation state quantity from those operation state quantities. The steering operation determining unit 144 determines whether the steering operation is in an excessive state based on the steering operation state amount related to the steering operation among the acquired operation state amounts. The tire generated sound processing unit 146 performs a process of acquiring auxiliary information for detecting an excessive skid state of the vehicle based on the tire generated sound S detected by the tire generated sound detector 76. The tire characteristic information reading unit 148 reads the tire characteristic information T from the tag chip 86. In addition, for convenience, the figure shows that the tire characteristic information reading unit exists only inside the ECU 90. However, in practice, the tire characteristic information reading unit 148 includes the relay unit 24. The tension estimating unit 150 estimates the driver's tension based on the driver's heart rate H detected by the heart rate detector 82. The tire pressure processing unit 153 calculates the tire pressure P detected by the tire pressure sensor 88._airReceive information about The processing results of the above-described units are used for monitoring processing in the vehicle state monitoring processing unit 132.
[0117]
<Specific example of vehicle state monitoring processing>
The monitoring process of the vehicle state is performed by executing a monitoring process program stored in the ROM 94 of the ECU 90. In the present monitoring apparatus, a plurality of monitoring processes having different processes can be selectively performed, and each of them is performed by executing a routine corresponding to the processing included in the program. Hereinafter, some of the plurality of monitoring processes will be described with reference to FIG. 8 and a flowchart. Note that when any of the following routines is monitored by the routine, the routine is repeatedly executed at short time intervals during the processing.
[0118]
i) Comprehensive traveling abnormal state detection processing
This process is a process performed by executing the general running abnormal state detection processing routine shown in FIG. 9, and detects each state of high probability of excessive side slip such as de-wheeling, rollover, and spin, and determines each state. This is a process for issuing a corresponding alarm. In the processing according to this routine, first, in step 1 (hereinafter, abbreviated as “S1”; the same applies to other steps), a vehicle speed v, which is a vehicle operation state quantity, is acquired. The vehicle speed v is acquired by the vehicle operation state quantity acquisition processing unit 142. Specifically, the rotation speed of each wheel is calculated based on the wheel rotation angle θ detected by the wheel rotation angle sensor 74, and the calculation result is averaged. In the next S2, a wheel steering angle φ 'as a steering amount is obtained. The wheel steering angle φ ′ is also acquired by the vehicle operation state quantity acquisition processing unit 142. Specifically, it is calculated based on the operation angle φ detected by the steering angle sensor 80 and the steering gear ratio unique to the steering device 114.
[0119]
The ROM 94 stores the vehicle speed v, the wheel steering angle φ 'and the theoretical ground contact area S.^*And data created based on the vehicle model. Such data is referred to as so-called "map data", and in S3, based on the obtained vehicle speed v and wheel steering angle φ ', a theoretical ground contact area corresponding to the operation state of the vehicle in accordance with the map data. S^*Is estimated.
[0120]
In subsequent S5, the contact area S of each of the four wheels, which is the contact surface state quantity, is acquired. The contact area S is acquired by the contact surface state acquiring unit 130. Although the acquisition process is performed based on the basis factor amount I detected by the basis factor amount detector 72, the acquisition process based on the detection result of the tread portion radial displacement detector 14 may be performed, and the detection result of the external pressure detector 50 may be used. The acquisition process may be based on The specific process may follow the process described above, and a description thereof will be omitted.
[0121]
Next, in S6, a slip angle α generated at the wheel, which is a wheel behavior-related state quantity, is estimated. More specifically, first, the center of gravity (center of gravity) O of the ground contact surface is geometrically processed by the ground contact surface state acquisition unit 130 based on the basic factor amount I obtained earlier._sIs calculated and its center of gravity O is calculated._sOf center of gravity ΔO which is the amount of deviation of the tread portion 14 from the center in the width direction._sIs acquired as the shape specifying amount of the ground contact surface (see FIG. 4). Center of gravity deviation ΔO_sAnd the slip angle α are stored in the ROM 94 as separate map data, and then the center-of-gravity shift ΔO obtained by the wheel behavior-related state quantity estimating unit 134 according to the map data._sIs estimated. When the inspection result by the external pressure detector 50 is used, the center of gravity deviation ΔO_sInstead of the pressure center of gravity O, which is the center of gravity determined by weighting with pressure._pDeviation amount ΔO_pMay be estimated based on the slip angle α.
[0122]
In the next S6, the probability of derailing is determined based on the acquired contact area S. This determination is made by the traveling abnormal state detection unit 136. Specifically, one of the four wheels
S <S^*/ 2
Is satisfied, the contact area of the wheel is too small, so that it is detected that there is a high probability that the wheel will be released. If it is determined in step S6 that the probability of the derailing is high, a derailing alarm is issued in step S7. A signal to that effect is sent from the abnormal state notification processing unit 140 to the notification device 122 provided in the instrument panel, and the notification device 122 turns on a predetermined indicator light and sounds a predetermined warning sound.
[0123]
Unless the determination condition in S6 is not satisfied, the process in S8 is performed. S8 is performed by the abnormal traveling state detection unit 136, and the likelihood of rollover during a sharp turn is determined based on the contact area S and the decrease rate ΔS of the contact area. When the vehicle rolls over while turning, the turning inner wheel rises. This processing detects this phenomenon as soon as possible. The contact area S acquired in the previous execution of this routine is stored in the RAM 96, and the difference between the contact area S acquired this time and the previous contact area S is determined as the contact area reduction speed ( If the contact area decreases, the sign becomes negative.) In addition, the discrimination between the inner wheel and the outer wheel is made based on the detected operation angle φ. Specifically, one of the two front and rear wheels serving as turning inner wheels is determined by the following two conditions:
S <S^*/ 4
ΔS <ΔS₀
When the condition is satisfied, it is detected that the vehicle is likely to roll over. ΔS₀Is a set threshold value, and is a value set based on a value obtained by calculating a change in the contact area when the steering wheel is operated at various operation angular velocities at various vehicle speeds according to the vehicle model. In other words, the value is set to such a value that it can be determined that the vehicle is in a sharp turning state when the further decreasing speed becomes greater. That is, in the present detection processing, when it is determined that the ground contact area S of the turning inner wheel becomes abnormally small and the vehicle is in a sharp turning state, it is detected that the possibility of rollover is high. If it is determined that the probability of rollover is high, a rollover warning is issued in S9. A signal is sent from the abnormal state notification processing unit 140 to the notification device 122, a predetermined indicator light is turned on, and a predetermined warning sound is emitted.
[0124]
Subsequent to S6 or S9, in S10, the probability of excessive skidding of the vehicle is determined based on the slip angle α that is the estimated wheel behavior related amount. Maximum slip angle α for maximum lateral force_max ^*Can be considered as a characteristic value depending on the tire. The slip angle α is the maximum slip angle α_max ^*If the vehicle speed exceeds the threshold value, the vehicle is likely to cause excessive side slip. This detection processing is performed by the traveling abnormal state detection unit 136 based on the theory. Note that the maximum slip angle α_max ^*Is stored in the tag chip 86 as a unique value for each tire. In an initial setting process when the ignition switch of the vehicle is turned ON, the information is read by the tire characteristic information reading unit 148 and stored in the RAM 96. You. In this detection processing, specifically, one of the four wheels
α> α_max ^*
Is satisfied, it is detected that the vehicle is in a state of high probability of excessive skidding. When the possibility of excessive skidding is detected, in S11, a signal is sent from the abnormal state notification processing unit 140 to the notification device 122, a predetermined indicator light is turned on, and a predetermined warning sound is sounded. If the probability of excessive sideslip is not detected, S11 is skipped. As described above, a series of processing is executed, and one execution of the present processing routine ends.
[0125]
ii) Grounding load etc. estimation / standing wave detection processing
This process is a process that is performed by executing the grounding load etc. estimation / standing wave detection processing routine shown in FIG. 10, estimates the grounding load of each wheel from the grounding surface information, and estimates the cornering force and camber angle. And a process for detecting the occurrence of the standing wave phenomenon. In the processing according to this routine, first, in S21, the ground contact surface length l of each of the four wheels, which is the shape specific amount of the ground contact surface,_xIs obtained. More specifically, based on the detection result of the tread portion radial displacement detector 14, the circumferential length l at each of a plurality of different positions in the width direction of the tread surface._x(B_-2) ~ L_x(B₂) Is acquired (see FIG. 2). Then, in S22, the acquired ground contact surface length l_x, The contact area S of each wheel, which is the contact surface state quantity, is acquired. The acquisition of these contact surface state quantities is performed by the contact surface state quantity acquisition unit 130, but their specific processes may follow the processes described above, and a description thereof will be omitted.
[0126]
Next, in S23, the tire pressure P of each wheel is obtained._airIs obtained. Specifically, the tire pressure P detected by the tire pressure sensor 88_airIs obtained by the tire pressure processing unit 152. Subsequently, in S24, the following equation:
W = P_air× S
, The ground contact load W of each wheel is estimated.
[0127]
Next, in S25, the cornering force CF and the camber angle β generated in each wheel are estimated. As described above, based on the vehicle model, the ground contact surface length l_x(B_-2) ~ L_x(B₂), The relationship between the cornering force CF and the camber angle β is created as map data, and in the present estimation processing, the acquired contact surface length l_x(B_-2) ~ L_x(B₂), And CF and β are estimated based on the map data. The map data is stored in the tag chip 86 for each tire as tire characteristic information, and is read by the tire characteristic information reading unit 148 in an initial setting process when the ignition switch of the vehicle is turned on. , Are stored in the RAM 96. Although the explanation is simplified here, CF and β are actually the vehicle speed v and the tire pressure P_airAnd the map data for estimating them are v, P_airIn the estimation, the vehicle speed v estimated from the wheel rotation angle θ (refer to the integrated traveling abnormal state detection processing) and the tire pressure P acquired earlier_air, Appropriate map data is selected.
[0128]
Subsequently, in S26, the road surface friction coefficient μ, which is the friction coefficient between the tire and the road surface, is calculated by the following equation:
μ = CF / W
Is estimated according to W, CF, β, and μ are wheel behavior-related state quantities, and the above-described process of estimating them is performed by the above-described wheel state-related state quantity estimating unit 134.
[0129]
In the following S27, the acquired tire pressure P_airThe estimated ground contact load W, cornering force CF, camber angle β, road surface friction coefficient μ, and the like are sent by the monitoring information supply unit 138 as real-time information to each vehicle-mounted device that is electronically controlled. In each vehicle-mounted device, control is performed based on the transmitted information. Specifically, for example, the grounding load W is used for vehicle attitude control (VCS control) or the like in the brake device 112 or the like, for height control control or the like in the suspension device 118, and the camber angle β is used for the VCS control or the suspension device 118. , And the road friction coefficient μ is used for changing a control threshold value in antilock brake control, VCS control, or the like. It should be noted that the probability of the vehicle rolling over is detected based on the camber angle β, and that the vehicle is traveling on a low μ road based on the road surface friction coefficient μ, and a warning is issued to the driver based on these detection results. It is also possible to emit.
[0130]
At S28, the previously acquired ground contact surface length l_x, A standing wave phenomenon is detected. The detection processing is performed by the traveling abnormal state detection unit 136, and specifically, the contact surface length l at each position in the width direction._x(B_-2) ~ L_x(B₂) Is the set threshold value, the critical contact surface length l_x0Is exceeded, it is determined that the tire has a standing wave phenomenon. If it is determined that the phenomenon has occurred, a warning is issued to the driver in subsequent S29. Specifically, a signal to that effect is sent from the abnormal state notification processing unit 140 to the notification device 122 provided in the instrument panel, and the notification device 122 turns on the indicator light indicating the tire where the phenomenon occurs, Sounds a predetermined warning sound. When S29 ends, or when it is determined in S28 that the standing wave phenomenon has not occurred, S29 is skipped and one execution of this processing routine ends.
[0131]
iii) Rollover detection processing based on internal / external surface pressure difference
This process is a process performed by executing the inside / outside surface pressure difference-dependent rollover detection process routine shown in FIG. This is a process of detecting a state in which a rollover is likely to occur and issuing an alarm. In the process according to this routine, first, in S31, the vehicle speed v, which is the vehicle operation state quantity, is obtained, and in the next S32, the wheel steering angle φ 'as the steering amount is obtained. These acquisition processes are the same as those in the above-described comprehensive traveling abnormal state detection process, and thus description thereof will be omitted.
[0132]
Here, the criterion regarding the inner and outer surface pressure difference will be described. As shown in FIG. 12A, the ground plane 40 can be divided into left and right regions with a center line in the width direction interposed therebetween. The ground contact surface 40 shown in the figure is a wheel on the left side of the vehicle._OAnd the area on the right is the inner area R_I(The opposite is true for the right wheel). The ground contact surface 40 shown in the figure is a state where the vehicle is turning to the right, and as described above, both the left and right wheels are in the region outside the turn (the outside region R in the vehicle left wheel in the diagram)._O, For the right wheel of the vehicle, the inner area R_I) Is in the area inside the turn (the inner area R for the left wheel of the vehicle in the figure)._I, For the right wheel of the vehicle, the outer region R_O) Is higher than the contact pressure. In this processing, a state in which the probability of rollover is high is determined based on the difference in the contact pressure. More specifically, with respect to the midpoint O of the line connecting the two ground contact surfaces on the center line in the width direction of the tire, a distance equal to the outside direction and the inside direction on the line in the width direction orthogonal to the center line. The two separated points are referred to as outer reference points Q_O, Inside reference point Q_IAnd each reference point Q_O, Q_IOuter contact pressure P which is the contact pressure at_O, Inner contact pressure P_IAs the contact pressure P_O, P_IAbsolute value (| P_O-P_I|) Is defined as a difference ΔP_{I / O}And the internal and external pressure difference ΔP_{I / O}Thus, the probability of rollover is determined.
[0133]
The ROM 94 stores the vehicle speed v and the wheel steering angle φ ′, and the internal / external surface pressure difference ΔP estimated therefrom._{I / O}Is the theoretical internal and external pressure difference ΔP_{I / O} ^*The map data created based on the vehicle model is stored. In S33, based on the acquired vehicle speed v and the wheel steering angle φ ′, 4 Theoretical internal and external pressure difference ΔP according to the operating state of the vehicle for each of the two wheels_{I / O} ^*Is estimated.
[0134]
In subsequent S34, based on the detection result by the external pressure detector 50, the inner and outer surface pressure difference ΔP_{I / O}Is acquired (see FIG. 4). In the next S35, the probability of rollover is detected. This detection is performed by the traveling abnormal state detecting unit 136, and the inner / outer surface pressure difference ΔP obtained for any of the wheels is obtained._{I / O}Is the theoretical internal and external pressure difference ΔP_{I / O} ^*Allowable pressure ΔP as margin₀Is exceeded, it is determined that the probability of rollover is high. That is, the internal and external surface pressure difference ΔP_{I / O}Is large, for example, it can be considered that the vehicle is in a sharp turning state, and it is estimated that the possibility of rollover is high.
[0135]
If it is determined that there is a high possibility of rollover, a rollover warning is issued in subsequent S36. A signal to that effect is sent from the abnormal state notification processing unit 140 to the notification device 122 provided in the instrument panel, and the notification device 122 turns on a predetermined indicator light and sounds a predetermined warning sound. This warning assists the driver in performing a rollover avoidance operation. When S36 ends or when it is not determined that the possibility of rollover is high, S29 is skipped and one execution of the present processing routine ends.
[0136]
The inside / outside surface pressure difference is a difference between the contact surface pressures at two set points. Instead, for example, as shown in FIG._OSurface pressure and inner area R_IIt is also possible to perform the above-described detection processing using the difference between the average surface pressure and the average surface pressure as the difference between the inner and outer surface pressures. Also, the outer region R_OAnd the inner region R_IIt is also possible to perform a similar detection process based on the difference from the load applied to the whole.
[0137]
iv) Side slip detection processing dependent on high contact pressure area
This processing is performed by executing the high surface pressure area-dependent side slip detection processing routine shown in FIG. 13, and based on the position in the width direction of the area where the contact surface pressure is equal to or higher than the set contact surface pressure on the contact surface. This is a process for detecting a state of high probability of excessive skidding such as that described above, and responding to it. In this process, first, in S41, the operation angle φ, which is the operation amount of the steering device 114 detected by the steering angle sensor 80, is acquired. In the next S42, the operation speed ω, which is the rotational angular speed of the steering wheel, is obtained from the difference between the operation angle φ obtained this time and the operation angle φ obtained last time. The operation angle φ and the operation speed ω are the operation state quantities of the steering device 114, that is, the operation state quantities of the vehicle, and these are acquired by the vehicle operation state quantity acquisition processing unit 142.
[0138]
In the next S43, the steering operation determination unit 144 determines whether the steering operation is in an excessive state. Specifically, the operation angle φ is equal to the set threshold angle φ₀Is larger and the operation speed ω is equal to the set threshold speed ω₀If it is larger (strictly, larger in the turning direction), it is determined that the steering operation is in an excessive state. In this process, the following detection process is executed only when the steering operation is in the excessive state.
[0139]
If the steering operation is in the excessive state, the processing of S44 and thereafter is performed. As described with reference to FIG. 6 as well, the maximum contact pressure P_maxBecomes higher, and the maximum surface pressure point Q_maxAlso shifts. The process of this routine uses this phenomenon to determine the probability of excessive skidding. FIG. 14 shows the shape of the contact surface and the distribution of the contact surface pressure in the width direction. As shown in the lower diagram of FIG. 14, when the degree of the side slip state increases, a contact pressure distribution as shown by a solid line is shown. The two-dot line indicates the contact pressure distribution in a state in which the skid does not slide. As can be understood from this comparison, there is a high pressure region in the left area of the contact surface. In S44, based on the detection result of the external pressure detector 50, the set threshold pressure P_HThe contact area R exceeds_HAnd the high contact surface pressure region R_HIt is determined whether or not there is. In other words, the maximum contact surface pressure P acquired as the contact surface state quantity by the contact surface state quantity acquisition unit 130_maxIs the predetermined threshold pressure P_HIt is determined whether it is higher. High contact pressure area R_HIf does not exist, this routine is terminated. If there is, the next S45 is executed.
[0140]
In S45, the high contact surface pressure region R in the width direction_HHigh-pressure area turning inside position Q which is the position in the turning inside direction of_RHAnd the shift amount ΔQ from the center in the width direction of the position._RHIs acquired as the contact surface state quantity by the contact surface state quantity acquisition unit 130. FIG. 14 shows a state where the vehicle turns rightward, and the high contact surface pressure region R_HThe rightmost part of is the high-pressure area turning inside position Q_RHAnd the shift amount from the center of the ground plane in the width direction at that point is the shift amount ΔQ of the high pressure region._RHIt is said. In the following S46, the acquired shift amount ΔQ_RHIs set to the threshold shift amount ΔQ_RH014, that is, in FIG. 14, the ground contact pressure region R higher than the set position._HIs located outside the turn, it is determined that the probability of excessive side slip is high. S44 and S46 are performed by the traveling abnormality state detection unit 136, and the detection processing of this routine in which S44 and S46 are combined, that is, both the maximum surface pressure of the contact surface and the degree of deviation in the width direction of the surface pressure distribution are performed. That is, the process is to determine the abnormal traveling state based on the above.
[0141]
If the possibility of excessive skidding is detected, a process for dealing with excessive skidding is performed in S47. Specifically, first, a signal is sent from the abnormal state notification processing unit 140 to the notification device 122, a predetermined indicator light is turned on, and a predetermined warning sound is emitted. Then, the monitoring information supply unit 138 supplies the information to, for example, the engine device 110 and the transmission device 116. Based on this information, the engine device 110 limits the number of revolutions, and the transmission device 116 prohibits gear change. If S47 is terminated or if it is not determined that the possibility of excessive sideslip is high, S47 is skipped and one execution of the present processing routine is terminated.
[0142]
v) Handle removal detection processing
This process is a process performed by executing the steering wheel picking detection routine shown in FIG. 15, and based on the lateral force generated on each of the wheels, specifically, the two front wheels that are the steered wheels, the steering wheel picking state is determined. This is a process of detecting and responding to it. The description of the processing according to this routine will be made with reference to FIG. 16 as appropriate.
[0143]
First, in S51, a vehicle speed v, which is a vehicle operation state quantity, is obtained, and in the next S52, a wheel steering angle φ 'as a steering amount is obtained. These acquisition processes are the same as those in the above-described comprehensive traveling abnormal state detection process, and thus description thereof will be omitted. Subsequently, in S53, the theoretical lateral force F of the left and right front wheels determined by the operation state of the vehicle._R ^*, F_L ^*Is estimated on the basis of the vehicle speed v and the wheel steering angle φ ′, and the sum of them is the theoretical lateral force sum ΣF^*Is required. The ROM 94 stores the vehicle speed v, the wheel steering angle φ ', and the theoretical lateral force F._R, F_LIs stored, and the theoretical lateral force F_R ^*, F_L ^*Is estimated, the map data is referred to.
[0144]
In the next step S54, the contact surface state distribution of each of the two front wheels is acquired by the contact surface state acquisition unit 130 as the contact surface state amount. More specifically, as shown in FIG. 16A, the ground plane 40 has four regions R in the width direction._-2~ R₂(Generally referred to as “region R”) are set separately, and the contact pressure P for each region R is set._R-2~ P_R2(Collectively, "contact pressure P_RIs sometimes obtained based on the detection result of the external pressure detector 50 (see FIG. 4). The contact pressure P_RIs the ground load W applied to the region R._RIs the area S of the region R_RDivided by Obtained contact pressure P_RIndicates a distribution as shown in FIG. 16B, for example.
[0145]
Next, in S55, the acquired contact pressure P_RCamber angle β of each of the left and right front wheels based on the distribution state of_R, Β_LIs estimated. As shown in FIG. 16C, when the vehicle travels on a rough road with a rut or the like, the camber angle β of the wheel changes according to the inclination of the road surface. As described above, the change in the camber angle β appears as a change in the state of the ground contact surface. The estimation using this phenomenon is performed. The estimation is performed by the wheel behavior-related state quantity estimating unit 134. The ROM 94 has a contact pressure P_RMap data for associating the distribution state of the camber angle with the camber angle β, and referring to the map data, the camber angle β_R, Β_LIs estimated.
[0146]
Next, in S56, the lateral force F of each of the left and right wheels is obtained._R, F_LAnd the sum of the lateral forces ΣF is the estimated camber angle β of each of the left and right front wheels._R, Β_LIt is performed based on. As conceptually shown in FIG. 16D, the camber angle β and the lateral force F generated on the wheel have a correlation, and map data for associating the two is stored in the ROM 94. Lateral force F_R, F_LIs estimated by the wheel behavior-related state quantity estimating unit 134, at which time the map data is referred to. Lateral force F of each wheel_R, F_LAre estimated, they are summed to calculate the sum of lateral forces ΣF.
[0147]
In subsequent S57, the state in which the steering wheel is taken is detected by the traveling abnormality state detection unit 136. More specifically, the sum of the lateral forces ΣF obtained as a result of the estimation and the sum of the theoretical lateral forces ΣF^*Is different from the set threshold value ΔΣF₀Is exceeded, it is determined that the steering wheel is ready to be taken. Note that this threshold Δ 閾 値 F₀Is a value corresponding to the frictional force of the steering device 114.
[0148]
If it is detected that the steering wheel has been taken, corresponding processing is performed in S58. Specifically, first, a signal is sent from the abnormal state notification processing unit 140 to the notification device 122, a predetermined indicator light is turned on, and a predetermined warning sound is emitted. Then, the monitoring information supply unit 138 supplies the information to the steering device 114. In the steering device 114, for example, when the steering device 114 is a so-called power steering device, a counter force corresponding to the difference ΔΣF in the lateral force sum is applied to the wheels. This is so-called preload control. Note that, in the case of a steering device of a so-called steer-by-wire type, in which a steering unit is separated from a steering unit, it is possible to correct and steer the steered wheels separately from the operation of the steering wheel. When S58 is terminated or when it is determined that the handle is not taken, S58 is skipped and one execution of the present processing routine is terminated.
[0149]
In the detection process of the steering wheel being taken, the lateral force F generated on the wheel is estimated based on the camber angle β after estimating the camber angle β of the wheel._RIt is also possible to directly estimate the lateral force F from the distribution state of. In that case, the contact pressure P_RMay be stored, and the map data may be referred to. In addition, the detection process can detect that the steering wheel has been taken even while the vehicle is turning. For example, the detection process can be performed in a processing mode in which the steering wheel is taken only when the vehicle is traveling straight. In this case, S51 to S53 are omitted, and the theoretical lateral force sum 横 F^*Is set to 0, and a series of processes may be performed.
[0150]
vi) Side slip detection processing based on tire noise
This process is a process performed by executing the tire-sound-dependent side-slip detection process routine shown in FIG. 17. In addition to the state of the contact surface pressure on the contact surface, the excessive spin and the like are generated based on the sound generated from the tire. This is a process for detecting a state in which the probability of side slip is high. In the processing according to this routine, first, in S61, a wheel steering angle φ 'as a steering amount is obtained by a process similar to that in the above-described comprehensive traveling abnormal state detection processing. Subsequently, in S62, the contact surface pressure P (contact load W / contact area S) of each of the front and rear turning inner wheels (wheels on the side close to the turning center) is acquired as a contact surface state quantity. The determination as to whether or not the wheel is a turning inner wheel is made based on the wheel steering angle φ ′. The process of acquiring the contact surface pressure P is performed by the contact surface state quantity acquisition processing unit 130, but may be the acquisition process based on the detection result of the tread portion radial displacement detector 14 as described above. The acquisition process may be based on the detection result of the device 50.
[0151]
Subsequently, in S63, the sound pressure NP of the tire generated sound N is obtained. The tire generated sound pressure NP is acquired by the tire generated sound processing unit 146 based on the tire generated sound N detected by the tire generated sound detector 76. The so-called squeal sound generated by slipping between the tire and the road surface in the tire generated sound N has a high sound pressure in a certain frequency range (for example, 500 Hz to 1500 Hz), so the tire generated sound processing unit 146 performs a filtering process. Thus, the sound pressure in the frequency range is used to detect the traveling abnormality. Further, since the squeal sound at the time of the skid is large at the turning outer wheel (wheel farther from the turning center), only the sound pressure of each of the front and rear turning outer wheels is acquired.
[0152]
Next, in S64, the threshold angle φ at which the wheel steering angle φ is set is set.₀'Is determined. This determination is made by the steering operation determination unit 144, and φ is φ₀If it is smaller than ', the routine is terminated assuming that excessive side slip does not occur because the steering wheel is not turned greatly, and if it is larger, the next S5 is executed. In S65, the threshold pressure P at which the contact surface pressure P of one of the two turning inner wheels obtained earlier is set.₀Is smaller than the threshold time t_pIt is determined whether the above is continued. If the possibility of occurrence of excessive side slip is high, a load shift occurs to the turning outer wheel side, and the contact pressure of the turning inner wheel decreases. This determination is based on the phenomenon, and the contact pressure P is equal to the threshold pressure P₀If the smaller state is not continued, this routine is ended, and if it is continued, the next S66 is executed. In S66, the threshold sound pressure NP at which the tire-generated sound pressure NP of one of the two turning outer wheels obtained earlier is set.₀The greater the state is, the set threshold time t_nIt is determined whether the above is continued. If it has not been continued, this routine ends. If it has been continued, the next step S67 is executed. The determinations in S65 and S66 are both performed by the traveling abnormality state detection unit 136, and a state in which the vehicle is highly likely to be excessively skid is detected by these determinations. If it is determined that the probability of excessive lateral slip is high, in S67, a signal is sent from the abnormal state notification processing unit 140 to the notification device 122, a predetermined indicator light is turned on, and a predetermined warning sound is sounded. As described above, a series of processing is executed, and one execution of the present processing routine ends.
[0153]
In the actual running of the vehicle, the contact surface state quantity changes even by slight ups and downs of the road surface, and therefore, it may be determined that the vehicle is in the traveling abnormal state even if it is not in the traveling abnormal state. Normal detection may not be possible due to a so-called noise phenomenon. In this processing, the determination is made on the condition that the predetermined state is continued for a predetermined time, and the detection is less affected by such a noise phenomenon, and the detection accuracy is good. Therefore, in order to improve the detection accuracy and the estimation accuracy, it is possible to adopt a determination method on the condition that the predetermined time is continued, in a process by a routine other than this routine.
[0154]
vii) Tension-dependent rollover detection processing
This process is a process that is performed by executing a tension-based rollover detection process routine shown in FIG. 18, and detects a state in which the probability of rollover is high only when it is determined that the driver's tension is high, This is processing corresponding to the state. In this process, first, in S71, the heart rate H of the driver is detected by the heart rate detector 82. In the following S72, the degree of tension is estimated. This estimation is performed by the tension estimation unit 150. Specifically, the normal heart rate H of the detected heart rate H₀Is the set tension determination coefficient k₁If it exceeds (for example, a value such as 1.2), it is determined that the driver is in a nervous state. Normal heart rate H₀May be registered and stored in advance for the value of the individual driving the vehicle, and the value of that person may be adopted in accordance with the driver's selection, or when the ignition switch is turned on. The value may be a value detected by the heart rate detector 82 in the initial processing. If it is determined that the user is not in a nervous state, the execution of this routine ends. If it is determined that the user is in a nervous state, the next step S73 is executed.
[0155]
In S73, the operation speed ω, which is the steering operation state quantity, is acquired. This acquisition processing is the same as the processing in the above-described maximum surface pressure position-dependent side slip detection processing, and thus description thereof will be omitted. In the following S74, the acquired operation speed ω is changed to the set threshold speed ω.₀Is determined. This determination is made by the steering operation determination unit 144, and ω becomes ω₀If not, the routine ends. If it does, it is determined that the steering wheel has been suddenly operated, and S75 and subsequent steps are executed. That is, in the present process, when the driver is nervous and the steering operation is excessive, the process of detecting the probability of rollover is performed.
[0156]
In S75, based on the direction of the steering operation, it is specified whether each of the four wheels is a turning inner wheel or a turning outer wheel. In subsequent S76, the turning inner wheel contact surface pressure P which is the contact surface pressure of each of the two front and rear wheels specified as the turning inner wheel._INAnd the turning outer wheel contact surface pressure P, which is the contact surface pressure of each of the two front and rear wheels specified as the turning outer wheel._OUTAre obtained as the contact surface state quantities. These contact pressures P_IN, P_OUTIs equivalent to a value obtained by dividing the contact load W on the entire contact surface by the contact area S of the contact surface. These acquisitions are performed by the ground contact surface state acquisition processing unit 130, but may be based on the detection result of the tread radial displacement detector 14 described above, and may be detected by the external pressure detector 50. It may be based on the result.
[0157]
In the following S77, the turning inner wheel contact surface pressure P_INAnd outer contact pressure of turning outer ring P_OUTBy comparing with, the probability of rollover is determined. Specifically, the two turning inner wheels and the turning outer wheel are divided into front wheels and rear wheels, respectively, and the turning inner wheel and the turning outer wheel of the front wheel are compared, and the turning inner wheel and the turning outer wheel of the rear wheel are compared. Then, at either the front wheel or the rear wheel, the turning inner wheel contact surface pressure P_INTurning outer ring contact pressure P_OUTIs the set load movement determination coefficient k₂If it falls below, it is determined that the possibility of rollover cannot be ignored. In other words, the determination is made based on how much the load moves to the turning outer wheel side when the vehicle turns. If it is determined that the possibility of rollover can be ignored, this routine ends. If the possibility of rollover cannot be ignored, the next step S78 is executed.
[0158]
In S78, the vehicle lateral acceleration G detected by the lateral G sensor 84 is obtained by the vehicle operation state amount acquisition processing unit 142. In S79, the detected vehicle lateral acceleration G is set to the set threshold acceleration G.₀It is determined that there is a high probability that the vehicle will roll over if it exceeds. The determinations in S77 and S79 are performed by the abnormal traveling state detection unit 136, and the abnormal traveling state of the vehicle is detected through these two determinations. If it is determined that there is no possibility of rollover, this routine is ended. If it is determined that the probability of rollover is high, a process corresponding to rollover is performed in S80. Specifically, in the corresponding process, first, a signal is sent from the abnormal state notification processing unit 140 to the notification device 122, a predetermined indicator light is turned on, and a predetermined warning sound is sounded. Then, the monitoring information supply unit 138 sends the information to the on-vehicle device that is performing the attitude control of the vehicle, and in the on-vehicle device, increases the control gain value in the execution of the attitude control according to the information. Is performed. Further, for example, in the suspension device 118, performing control such as hardening the turning outer wheel side or lowering the vehicle height is also effective for suppressing rollover. After the above series of processing is completed, one execution of this processing routine is completed.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a tread radial displacement detector provided in a contact surface information acquisition device according to an embodiment of the present invention.
FIG. 2 schematically shows a relationship between a change in tread radial displacement associated with rotation of a wheel detected by the tread radial displacement detector and a contact surface state quantity acquired based on the change. FIG.
FIG. 3 is a diagram illustrating a configuration of an external pressure detector included in a contact surface information acquiring device according to an embodiment of the present invention.
FIG. 4 is a diagram schematically showing a detection result by the external pressure detector.
FIG. 5 is a diagram showing a state of a ground contact surface acquired by a contact surface state quantity acquisition device provided with the tread portion radial displacement detector, in a case where parameter values relating to wheel behavior are variously different. .
FIG. 6 shows a state of the ground contact surface acquired by the contact surface state quantity acquisition device including the external pressure detector, showing a state where the slip angles of the wheels are different.
FIG. 7 is a diagram schematically showing a configuration of a vehicle equipped with a vehicle condition monitoring device according to an embodiment of the present invention.
FIG. 8 is a functional block diagram showing functional parts of a vehicle state monitoring device according to an embodiment of the present invention.
FIG. 9 is a flowchart of an integrated traveling abnormal state detection processing routine executed by the vehicle state monitoring device according to the embodiment of the present invention.
FIG. 10 is a flowchart of a grounding load etc. estimation / standing wave detection processing routine executed by the vehicle state monitoring device according to the embodiment of the present invention.
FIG. 11 is a flowchart of an inside / outside surface pressure difference dependent rollover detection processing routine executed by the vehicle state monitoring device according to the embodiment of the present invention.
FIG. 12 is a conceptual diagram for describing a criterion for acquiring an internal / external surface pressure difference.
FIG. 13 is a flowchart of a high surface pressure region-dependent side slip detection processing routine executed by the vehicle state monitoring device according to the embodiment of the present invention.
FIG. 14 is a conceptual diagram illustrating a high-side-pressure-region-dependent sideslip detection process.
FIG. 15 is a flowchart of a steering wheel picking detection processing routine executed by the vehicle state monitoring device according to the embodiment of the present invention.
FIG. 16 is a conceptual diagram for explaining a handle taken detection process.
FIG. 17 is a flowchart of a tire-sound-dependent side slip detection processing routine executed by the vehicle state monitoring device according to the embodiment of the present invention.
FIG. 18 is a flowchart of a tension-dependent rollover detection processing routine executed by the vehicle state monitoring device according to the embodiment of the present invention.
[Explanation of symbols]
10: Wheel 12: Tire 14: Tread radial displacement detector 16: Tread 20: Ultrasonic probe 40: Ground plane 50: External pressure detector 52: Surface pressure sensor 58: Piezoelectric element 70: Wheel 72: Basic factor Quantity detector 74: Wheel rotation angle sensor 76: Tire sound detector 78: Steering wheel 80: Steering angle sensor 82: Heart rate detector 84: Lateral G sensor 86: Tag chip (tire characteristic information storage medium) 88: Tire pressure Sensor 90: Electronic control unit (ECU) 110: Engine device 112: Brake device 114: Steering device 116: Transmission device 118: Suspension device 122: Notification device
130: contact surface information acquisition processing unit 132: vehicle state monitoring processing unit 134: wheel behavior related state quantity estimation unit 136: running abnormal state detection unit 138: monitoring information supply unit 140: abnormal state notification processing unit 142: vehicle operation state Amount acquisition processing unit 144: steering operation determination unit 146: tire sound processing unit 148: tire characteristic information reading unit 150: tension estimation unit 152: tire pressure processing unit

Claims (24)

On the ground contact surface that is in contact with the road surface of the tire, a contact surface state amount acquisition unit that acquires a contact surface state amount that is a state amount indicating the state of the contact surface,
A vehicle state monitoring unit that performs a vehicle state monitoring process based on the acquired ground contact surface state quantity. The vehicle according to claim 1, wherein the vehicle state monitoring processing unit includes a traveling abnormal state detection unit that detects a traveling abnormal state that is an abnormal state of traveling of the vehicle based on the acquired contact state state quantity. Condition monitoring device. The traveling abnormal state detection unit, as the acquired contact state state quantity, based on at least one of the maximum surface pressure of the contact surface and the degree of deviation in the width direction of the contact pressure distribution, as the traveling abnormal state 3. The vehicle condition monitoring device according to claim 2, wherein the vehicle condition monitoring device detects an excessive side slip of the vehicle or a state of high probability of the slip. The traveling abnormal state detection unit detects a standing wave phenomenon as the traveling abnormal state or a state in which the probability of the standing wave phenomenon is high, based on the length of the contact surface as the acquired contact surface state quantity. The vehicle condition monitoring device according to claim 2. The traveling abnormal state detection unit is configured to determine a relationship between the acquired ground contact surface state quantity and a theoretical ground contact surface state quantity that is the theoretical ground contact state state quantity estimated based on a state in which the vehicle is operated. The vehicle condition monitoring device according to claim 2, wherein the traveling abnormal condition is detected based on the condition. The traveling abnormal state detection unit, based on the relationship between the area of the contact surface as the acquired contact surface state quantity and the theoretical contact area that is the area of the contact surface estimated as the theoretical contact surface state amount, 6. The vehicle condition monitoring device according to claim 5, wherein the vehicle condition monitoring device detects a derailment or a highly probable condition as the traveling abnormal condition. The traveling abnormal state detection unit, based on the relationship between the area of the contact surface as the acquired contact surface information amount, and the theoretical contact area that is the area of the contact surface estimated as the theoretical contact surface state amount 6. The vehicle condition monitoring device according to claim 5, wherein the vehicle condition monitoring device detects a rollover or a highly probable condition of the vehicle as the traveling abnormal condition based on the decreasing speed of the contact area. The traveling abnormal state detection unit, as the acquired contact surface information amount, by the surface pressure difference between a predetermined portion closer to the vehicle outside and a predetermined portion closer to the vehicle inside from the center in the width direction of the contact surface. Based on a relationship between a certain inner and outer surface pressure difference and a theoretical inner and outer surface pressure difference that is the theoretical inner and outer surface pressure difference estimated as the theoretical ground contact surface state quantity, the vehicle is likely to roll over as the vehicle state or is highly probable. The vehicle state monitoring device according to claim 5, wherein the state is detected. 2. The vehicle state monitoring processing unit according to claim 1, further comprising: a wheel behavior-related state quantity estimating unit that estimates a wheel behavior-related state quantity that is a state quantity related to a behavior of a wheel based on the acquired contact surface state quantity. The vehicle condition monitoring device according to claim 1. The wheel behavior-related state quantity estimating unit estimates the load applied to the contact surface based on the area of the contact surface as the acquired contact surface state amount and the air pressure of the tire, and obtains the acquired load. A cornering force generated by the wheel 2 as the wheel behavior-related state quantity is estimated based on a shape specifying amount capable of specifying the shape of the ground contact surface as a contact surface state quantity, and the estimated contact The vehicle condition monitoring device according to claim 9, wherein the vehicle condition monitoring device is configured to estimate a friction coefficient between a road surface and a tire as the wheel behavior-related condition quantity based on a load on the ground and the estimated cornering force. The vehicle state monitoring processing unit, based on the wheel behavior related state quantity estimated by the wheel behavior related state quantity estimating unit, based on a running abnormal state detection unit that detects a running abnormal state that is an abnormal state about the running of the vehicle The vehicle condition monitoring device according to claim 9, further comprising: The wheel behavior-related state quantity estimating section estimates a wheel slip angle as the wheel behavior-related state quantity, and the traveling abnormal state detecting section can obtain the estimated slip angle and the maximum lateral force. 12. The vehicle condition monitoring device according to claim 11, wherein the vehicle condition monitoring device detects an excessive side slip of the vehicle as the vehicle condition or a state of a high probability thereof based on a relationship with a maximum slip angle that is a theoretical slip angle. The traveling abnormal state detection unit, the estimated wheel behavior-related state quantity, and the theoretical wheel behavior-related state quantity that is the theoretical wheel behavior-related state quantity estimated based on the state in which the vehicle is operated. The vehicle condition monitoring device according to claim 11, wherein the abnormal condition is detected based on the relationship. The wheel behavior-related state quantity estimating unit is for estimating a lateral force generated on a wheel as the wheel behavior-related state quantity, and the traveling abnormal state detection unit is configured to calculate the theoretical wheel behavior-related state quantity. A method for detecting a state in which a steering wheel is taken or a state in which the steering wheel is highly likely to be taken as the traveling abnormal state, based on a relationship between a lateral force and a lateral force estimated by the wheel behavior-related state quantity estimating unit. A vehicle condition monitoring device according to claim 13. The vehicle condition monitoring device includes a tire noise detector that detects a tire noise that is a sound generated from the tire, and the traveling abnormal state detection unit further includes a tire noise detector that detects the tire noise detected by the tire noise detector. 14. The vehicle state according to claim 2, wherein an excessive side slip of the vehicle as the traveling abnormal state or a state of a high probability thereof is detected based on the sound. Monitoring device. The wheel state monitoring device includes a steering operation determining unit that determines whether the operation of the steering device is in an excessive state based on at least a steering operation state amount that is a state amount indicating the operation state of the steering device. 10. The abnormal traveling state detecting unit detects the abnormal traveling state when the steering operation determining unit determines that the steering operation is in an excessive state. The vehicle condition monitoring device according to any one of claims 11 to 15. 17. The vehicle state monitoring device according to claim 2, further comprising an abnormal state notifying section that notifies an abnormal state detected by the traveling abnormal state detecting section to a driver. The vehicle condition monitoring device according to claim 1. The vehicle condition monitoring device includes a tension estimation unit that estimates a driver's tension, and the vehicle condition monitoring processing unit changes a mode of the vehicle state monitoring process based on the estimated tension. The vehicle condition monitoring device according to any one of claims 1 to 17, wherein the vehicle condition monitoring device is a vehicle condition monitoring device. The vehicle condition monitoring device further includes a control unit that performs control using the monitor information, which is information relating to at least one of the acquired ground contact surface state amount and a result obtained by the monitoring process, using the monitor information. 19. The vehicle condition monitoring device according to claim 1, further comprising a monitoring information supply unit that supplies the monitoring information supply unit to the vehicle-mounted device. The contact surface state quantity acquisition unit,
A basic factor amount detector for detecting a basic factor amount which is a physical quantity related to a tread portion of a tire and is a basic factor for obtaining the contact surface state quantity, and a basic factor detected by the basic factor amount detector The vehicle state monitoring device according to any one of claims 1 to 19, further comprising a contact surface state quantity acquisition device that acquires the contact surface state amount based on the quantity. The basic factor amount detector includes a tread portion radial displacement detector that detects the radial displacement of the tread portion of the tire as the basic factor amount, and the tread portion state quantity acquisition device includes a tread portion radial direction. 21. The vehicle state monitoring device according to claim 20, wherein the ground state state quantity is obtained based on the displacement detected by a displacement detector. The basic factor amount detector includes an external pressure detector that detects, as the basic factor amount, an external pressure applied to each of one or more detection points of a tread portion of the tire from the outside thereof, and obtains the ground contact surface state amount. 22. The vehicle condition monitoring device according to claim 20, wherein the device acquires the ground contact surface condition amount based on an external pressure detected by the external pressure detector. The basic factor amount detector is provided on a wheel, and the ground contact surface state amount acquiring device is provided on a wheel, and a transmitting device that wirelessly transmits a signal regarding a detection value of the basic factor amount detector, 23. The vehicle condition monitoring device according to claim 20, further comprising: a receiving device provided on a vehicle body to receive the transmitted signal. A basic factor which is a physical quantity related to a tread portion of a tire and is a basic factor for obtaining a contact surface state quantity which is a state quantity indicating a state of the contact surface at a contact surface which is in contact with the road surface of the tire. A ground plane state quantity acquisition device, comprising a basic factor amount detector for detecting an amount, and acquiring the ground plane state quantity based on the basic factor amount detected by the basic factor amount detector.

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