JPH11304663A - Estimation operation device of center-of-gravity height of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rationally estimate the behavior of a vehicle such as a skid and a wheel lift by real-time operation, and to estimate the height of center of gravity. SOLUTION: The height of center of gravity is obtained according to a steering angle when a vehicle turns left and right or changes its lane and a roll angle being generated at that time. The transfer function of roll for the steering angle of a dynamics model with degree of freedom including the roll is equal to that of the roll for the steering angle being obtained by the AR method (auto-regressive method) from data being sampled from a loaded vehicle, thus deriving the height of center of gravity by comparing coefficients.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to attitude control of an automobile. INDUSTRIAL APPLICABILITY The present invention is used for a device that automatically controls the attitude of a vehicle in a stable direction based on the behavior of a running vehicle such as yaw or roll. The present invention, for example, by automatically detecting and calculating that the vehicle may be in a skidding state while traveling, by automatically controlling the brake pressure of all or some wheels, the vehicle The present invention can be used for an automatic control device that recovers to a state in which a side slip is less likely to occur. The present invention relates to attitude control for automatically restoring a stable state when a vehicle reaches a behavior not intended by a driver due to a driving operation exceeding the characteristics of the vehicle, such as a large steering wheel operation during high-speed running.
INDUSTRIAL APPLICATION This invention is utilized for rollover prevention of commercial vehicles, such as a bus and a truck.

[0002]

2. Description of the Related Art Conventionally, electronic control devices for brakes and vehicle stability control devices (VSC, Vehicle Stability Control) have been used.
Etc. are known. ABS (Antilock Brake System) is a typical system for electronic control devices related to brakes.
It is. This is to provide a rotation sensor on the wheel to detect the wheel rotation, and when the wheel rotation stops when the brake pressure is large, assuming that there was a slip between the wheel and the road surface,
The brake pressure is intermittently controlled. ABS has become widespread in passenger cars and freight cars, and has become widely known as a device that can handle while braking. As a typical device of the vehicle stabilization control device (VSC), a skid prevention device is known. This means that the course the driver is going to travel is read from the steering angle (steering angle) input by the driver, and if the vehicle speed is too high for that course, the driver will automatically enter without having to press the brake pedal. This is a device in which control for deceleration is performed and control such as distributing left and right brake pressures so as not to deviate from the course is performed.

[0003] A known vehicle attitude stabilizing device (VSC) (JP-A-63-279976, JP-A-2-112755, etc.) will be further described. When this is done, the direction of the vehicle changes and the vehicle rolls. At this time, if the tire of the inner wheel turning by steering exceeds the grip limit of the road surface, the inner wheel tends to be a so-called wheel lift, and the vehicle starts to skid. For example, when the driver steers to the left from a straight running state, the vehicle leans to the right. At this time, the vehicle turns in accordance with the steering in a normal state, but if the steering speed is too high relative to the traveling speed, the vehicle leans to the right and the left wheel is in a floating state, so that the driver Will move to the right from the intended direction. Such a behavior of the vehicle causes a deviation from the traveling lane or, in an extreme case, a rollover of the vehicle.

In a normal running state, the magnitude and speed of steering, the speed of the vehicle, the speed of lateral movement of the vehicle, and the speed of change in the direction of the vehicle (yaw rate, rotational acceleration of the vehicle around the vertical axis) are detected. A device has been developed which predicts the starting point of a skid of a wheel or the starting point of a wheel lift of an inner wheel by controlling the brake pressure of the wheel before the skid or the wheel lift starts. The brake pressure control of the wheels does not necessarily apply the same brake pressure to all the wheels, but applies a large or small brake pressure to one wheel to prevent the vehicle from skidding. Such an apparatus has been well studied not only for its basic structure and design, but also for its economy and durability, and has reached the stage of being mounted on a commercial product for a passenger car.

[0005] Such a conventional apparatus calculates a yaw rate from parameters relating to the current driving operation including steering and braking and parameters relating to the current behavior of the vehicle, that is, from the parameters at the current time. When it is determined that the yaw rate having the possibility of the sideslip that has been set and stored is reached, the brake pressure of the vehicle is automatically controlled. The possibility of this side slip is calculated by a transfer function from the vehicle operation data which is a driving operation input and various sensor outputs.

In the conventional transfer function calculation device, the calculation using the transfer function is a calculation method in which fast Fourier calculation is widely used. That is, the frequency of the operation input data and the behavior data is frequency-decomposed, and the response is approximated using a Fourier function. The fast Fourier operation has a convenient point such that a general-purpose analyzer that can be installed and used in a computer device can be easily obtained.

In such an apparatus for controlling the attitude of a vehicle, the position of the center of gravity of the vehicle is a very important parameter. The position of the center of gravity of a large commercial vehicle represented by a large truck changes depending on the state of the cargo. In the case of a bus, particularly in a route bus, the position of the center of gravity of the vehicle changes as passengers get on and off. Regarding the attitude control for preventing the rollover of the vehicle, the height of the center of gravity of the vehicle is an important parameter.

Conventionally, the center of gravity of a vehicle can be statically measured, but there is no method for measuring the center of gravity of a vehicle in real time in a running state. That is, while the vehicle whose center of gravity is to be measured is stopped on a horizontal road surface, the load distribution of each wheel is measured,
Next, the vehicle is moved to a road surface having a gradient in the front-rear direction and a road surface having a gradient in the left-right direction, and the load distribution of each wheel is measured, so that the position of the center of gravity including the height of the center of gravity is three-dimensionally measured. be able to.

FIGS. 21 to 23 show a conventional attitude control device.
This will be described with reference to FIG. FIG. 21 is a diagram showing an example of the overall configuration of conventional attitude control. The vehicle 1 is a controlled object of the attitude control device. The vehicle 1 is provided with steering, braking, acceleration, and other driving operation inputs, and the response thereto is the behavior of the vehicle. The vehicle 1 has an attitude control device 2 mounted thereon. The attitude control device 2 is a vehicle stabilization control device (VS
C) 3 and an electronically controlled braking device 4. The electronic control braking device 4 is a device represented by a conventional ABS means.

In order to observe the behavior of the vehicle as data, behavior data is output from sensors 11 mounted on the vehicle 1. The behavior data includes speed, lateral acceleration, yaw rate, roll rate, wheel rotation information, and others.

The vehicle stabilization control device 3 predicts and calculates the behavior of the vehicle using the driving operation input and the behavior data as input, and gives the result to the electronic control braking device 4. The electronically controlled braking device 4 also takes in driving operation input and behavior data, and additionally, a vehicle stabilization control device (VSC) 3
And outputs an automatic control output in a safe direction with respect to the driving operation input and the disturbance input to the vehicle 1, and this is a correction input.

FIG. 22 is a system configuration diagram of a conventional attitude control device. The control device 51 is an electronic device mounted on a vehicle including a computer circuit controlled by a program,
A vehicle stabilization control device (VSC) for calculating and outputting a vehicle motion state using a driving operation input of a vehicle and behavior data of the vehicle as inputs, and a driving operation input and a disturbance input according to the calculation output of the vehicle stabilization control device. Control means for giving a correction input to the vehicle to correct the vehicle safety.

The vehicle is equipped with a yaw rate sensor 52, a lateral acceleration sensor 53, a roll rate sensor 60, and a longitudinal acceleration sensor 61. The detection outputs of these sensors are connected to a control unit 51. Four wheels 54
Are respectively attached with wheel rotation sensors 55, and their detection outputs are also connected to the control device 51. A brake pressure sensor 57 is provided for the brake booster actuator 56.
The detection output is also connected to the control device 51. A steering angle sensor 59 is attached to the steering wheel 58, and the output is connected to the control device 51. A governor sensor 63 is incorporated in the governor 62 for controlling the internal combustion engine, detects the state of the governor 62, and a detection output thereof is connected to the control device 51. FIG. 23 is a perspective view showing an example of mounting each sensor on a vehicle. FIGS. 22 and 23 show a vehicle having a two-axis structure, but a large vehicle uses a three-axis or four-axis structure.

[0014]

However, in the fast Fourier calculation conventionally used in the transfer function calculation, (1) a long time data is required for a signal with a low frequency, and (2) the number of data. Is a power of 2 (8, 16, 32, 64
..), An appropriate number of data may not be obtained in some cases, and (3) a closed loop in which feedback control is performed cannot be operated. In particular, in commercial vehicles such as trucks and buses, there is a component having a vibration frequency of about 1/100 Hertz in the behavior data, and such behavior data is used to calculate a transfer function by fast Fourier computation. Requires real-time data over 200 seconds, at least twice that period. In this case, it is not possible to obtain a practical device for performing calculations in real time during traveling. This is a serious problem that hinders the realization of a commercial vehicle attitude control device.

In a large vehicle, depending on the state of the cargo,
Alternatively, the physical characteristics of the vehicle greatly vary depending on the number of passengers and the seating position. That is, in the case of a passenger car, even if the number of passengers varies, the weight of the passenger (for example, 50 kg per person) is equal to the total weight of the vehicle (for example, 2000 kg).
And the crew is small. Moreover, since the boarding position of the passenger is fixed at a position with a low center of gravity,
Even when the number of passengers fluctuates, even if the calculation is performed with the vehicle model holding the physical constants of the vehicle fixed, the calculation result of the attitude control device does not have a large effect. However, in the case of a heavy-duty vehicle, in the case of a freight vehicle, the weight of the entire vehicle and the position of the center of gravity greatly change between a case where there is no load and a case where there is a typical load close to the loadable limit. Therefore, since the physical characteristics of the vehicle greatly change, even if the calculation is performed using a fixed vehicle model, it does not become a realistic value.

Further, in a truck, the load is not always loaded in a constant state, and the weight and the position of the load or the position of the center of gravity change each time. Even in the case of a large bus, the number of passengers varies from zero to about 50 people, and the position of the passengers in the vehicle also changes each time. In the case of a regular bus, it will change for each stop. Therefore, if the vehicle model on which the attitude control is based is fixedly set, practical attitude control cannot be performed.

Considering the height of the center of gravity among the above parameters, there is conventionally a method of static measurement described in JIS security standards or the like. The height of the center of gravity could not be measured.

That is, in the conventional measuring method, it is impossible to use the current data on the change in the center of gravity of the vehicle. In particular, in a freight vehicle in which the weight and the appearance of a load change, the center of gravity of the vehicle cannot be measured each time the load is unloaded, and the attitude control is performed using the approximate value.

In particular, since the height of the center of gravity changes depending on the cargo style of the cargo, for example, the height of the center of gravity measured at the time of departure for delivery changes when the cargo is unloaded to the customer. It cannot be used as control device data. Therefore, a technology that can measure the height of the center of gravity in real time while traveling is required.

The present invention has been made in such a background, and an object of the present invention is to provide an attitude control device suitable for a large vehicle, particularly a commercial vehicle. An object of the present invention is to provide a posture control device for adapting to a large vehicle in which behavior data includes many low frequency components. The present invention
An object of the present invention is to provide a posture control device for adapting to a vehicle in which the state of a load or a passenger changes. An object of the present invention is to provide a posture control device in which a vehicle model automatically follows a change in the state of a load or a passenger. An object of the present invention is to prevent a large vehicle from deviating from a traveling lane and to prevent rollover by driving control that exceeds the characteristics of the vehicle. An object of the present invention is to provide a device that can estimate the height of the center of gravity of a vehicle in real time. An object of the present invention is to improve control accuracy of a vehicle attitude control device.

[0021]

According to the present invention, the height of the center of gravity is determined in real time. That is, the present invention is characterized in that the height of the center of gravity is obtained according to the steering angle when the vehicle turns right or left or changes lanes and the roll angle generated at that time.

The transfer function of the roll with respect to the steering angle of the dynamic model having the degree of freedom including the roll and the transfer function of the roll with respect to the steering angle obtained by using the AR method (autoregression method) from data collected from the actual vehicle are as follows. Because they are equal, we tried to derive the height of the center of gravity by comparing the coefficients.

Here, the AR method is a method in which a past data is multiplied by a weighting factor and the calculation is performed in reverse to obtain the current data. In general, when comparing the AR method and the fast Fourier calculation method (FFT), the FFT has advantages such as that a general-purpose analyzer can be easily obtained, and that when the calculation is started, the calculation is completed in a short time. In order to obtain an appropriate resolution for a low (long period) component, data over twice as long as the period is required. For example, the behavior data of a large vehicle includes a frequency component such as 1/100 Hertz (period of 100 seconds), so that the calculation cannot be performed in real time. On the other hand, in the AR method, a past data is multiplied by a weighting coefficient and the calculation is performed in reverse, so that a corresponding result can be obtained one by one, which is suitable as a calculation for real-time control. In the FFT method, the number of data is a power of 2, that is, 2 ⁿ
However, in the AR method, the number of data is not limited and the calculation can be performed using the data held at each time, so that the degree of freedom is increased. In the FFT method,
In principle, it is impossible to perform a loop, that is, a loop control in which the calculation result is immediately fed back to the behavior data. However, the AR method is suitable for closed-loop calculation, and is suitable for the attitude control of a vehicle. This is advantageous in a device in which loop control is always performed.

As described above, the present invention focuses on the movement in the roll direction with respect to the steering angle, and compares the coefficient of the transfer function between the movement model and the "AR method model" obtained from the experimental data to thereby determine the height of the center of gravity. Attempted estimation. As a result: It is quite possible to estimate the height of the center of gravity from these. 2. Difference in height of the center of gravity depending on the actual package, so-called flat load,
High load determination is also possible. It became clear that.

That is, the present invention relates to an apparatus for estimating the height of the center of gravity of a vehicle. Means for deriving the height of the center of gravity assuming that the coefficients of the respective orders with the transfer function of the roll with respect to the steering angle obtained from the data obtained by using the AR method (autoregression method) are equal to each other.

More specifically, the vehicle has an autoregressive method (A
R method), and a calculation circuit for a vehicle response automatically updated in real time in a running state by the driving method is provided, and the deriving means calculates a steering angle input by a driving operation in a state where the vehicle is running, by a differential operator s. When a roll generated in the vehicle by the steering angle is represented as a function φ (s) of a differential operator s, the transfer function of the roll with respect to the steering angle (φ (s) / δ (s) is expressed as a function δ (s). ) Represents the value hs · f (s) calculated from the equation of motion of the vehicle having the height of the center of gravity hs as a quadratic expression of the differential operator s, while the roll of the roll with respect to the steering angle calculated by the calculation circuit is calculated. The transfer function (φ (s) / δ (s)) is expressed as a quadratic expression of a differential operator s, and an equation in which the coefficients of the respective order terms of the quadratic expressions of the two differential operators s are equal to each other. Including means for estimating the height hs of the center of gravity Desirable. Thus, the height of the center of gravity can be estimated in real time by detecting the steering angle and the roll angle.

The apparatus further includes means for preferentially employing the height hs of the center of gravity obtained by an equation which assumes that the coefficients of the first-order terms of the differential operator s are equal to each other. Means for performing zero correction using the median value of the angle value and the measured roll angle value,
Means for setting a point in time at which the value of the roll angle becomes zero by this zero point correction including a range in which the measured roll angle change is large as a start point and an end point, and sampling between the start point and the end point; It is desirable to include a band-pass filter unit through which output data of the sampling unit passes. Thereby, the accuracy of estimating the height of the center of gravity can be improved.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1, 2, 9 and 10. FIG. FIG. 1 is a flowchart showing the procedure of the first embodiment of the present invention. FIG. 2 is a block diagram showing the procedure of the first embodiment of the present invention. FIG. 9 is a flowchart showing the procedure of the second embodiment of the present invention. FIG. 10 is a block diagram showing the procedure of the second embodiment of the present invention. The overall configuration is the same as that of the conventional example shown in FIGS.

The present invention relates to an apparatus for estimating the height of the center of gravity of a vehicle, and as shown in FIG. 1, a transfer function of a dynamic model having a degree of freedom including a roll with respect to a steering angle input by a driver during traveling. Means for deriving the height of the center of gravity assuming that the coefficients of the respective orders of the roll transfer function with respect to the steering angle obtained using the AR method (autoregression method) from the data collected from the actual vehicle are equal to each other are shown in FIG. A feature is provided in the control device 51 shown in FIG.

The control device 51 shown in FIGS. 22 and 23 is provided with a vehicle response calculation circuit that is automatically updated in real time in a running state by an autoregressive method (AR method). While the vehicle is traveling, the steering angle input by the driving operation is calculated by the function δ of the differential operator s.
(S), and when a roll generated in the vehicle by the steering angle is a function φ (s) of the differential operator s, a transfer function of the roll with respect to the steering angle (φ (s) / δ (s))
Represents the value hs · f (s) calculated from the equation of motion of the vehicle having the center of gravity height hs as a quadratic expression of the differential operator s, while transmitting the roll to the steering angle calculated by the arithmetic circuit. The function (φ (s) / δ (s)) is expressed as a quadratic expression of the differential operator s, and the center of gravity is calculated by an equation in which the coefficients of the respective order terms of the quadratic expressions of the two differential operators s are equal to each other. Estimate the height hs.

In the first embodiment of the present invention, as shown in FIG. 2, the height hs of the center of gravity obtained by the equation that the coefficients of the quadratic terms of the differential operator s are equal to each other is adopted. On the other hand, in the second embodiment of the present invention, as shown in FIG. 10, the height of the center of gravity hs obtained by the equation that the coefficients of the primary terms of the differential operator s are equal to each other is preferentially adopted. And

Further, in the second embodiment of the present invention, as shown in FIG. 9, the control device 51 performs a zero correction using the median value of the input steering angle value and the measured roll angle value. The time when the roll angle value becomes zero by the zero point correction including the range in which the measured roll angle change is large is set as a start point and an end point, and sampling is performed between the start point and the end point. And a band-pass filter through which the output data according to (1) passes.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a feature of a large vehicle, two axes, three
Since the vehicle is classified into an axle and an axle, and various types of wheelbases are present, the vehicle has different motion characteristics. FIG. 3 is a diagram showing the motion characteristics of the vehicle. The horizontal axis indicates frequency, and the vertical axis indicates gain and phase. When different wheelbases (WB (1) <WB (2) <WB (3)) of the same axle configuration are used, as shown in FIG. This indicates that the sensitivity is increased.

Also, from the viewpoint of the use of the vehicle, the axle load changes greatly when the vehicle is empty or loaded, and the center of gravity changes greatly depending on the type of package. Therefore, it is important to grasp the position and height of the center of gravity as motion characteristics. is there.

FIG. 4 is a diagram showing the relationship between the height of the center of gravity and the roll rate. The difference in roll characteristics depending on the height of the center of gravity is shown by data at the time of course change (required distance 40 m, speed 90 km / h). is there. Figure 4 (a) shows time on the horizontal axis.
In FIG. 4, the vertical axis indicates the steering angle, and in FIG. 4B, the vertical axis indicates the roll rate. When the height of the center of gravity is high, the roll rate is large and a phase delay occurs. Normally, the driver can sufficiently recognize the roll feeling that changes depending on the package, and safe driving is ensured. However, the present embodiment examines a method of estimating the height of the center of gravity using this feature.

FIG. 5 is a diagram showing a dynamic model used in the embodiment of the present invention. The transfer function of the roll for the steering of the dynamic model having the degrees of freedom including the roll as shown in FIG. 5 is equal to the transfer function of the roll for the steering obtained by using the AR method from the data collected from the actual vehicle. Therefore, coefficient comparison is performed to derive the center of gravity row.

(First Embodiment) A dynamic model of a vehicle is created, and a motion is described as shown in FIG. 5 according to a coordinate system fixed in advance in order to derive a transfer function of a roll with respect to a steering angle. In order to describe the relationship between the height of the center of gravity and the roll, three degrees of freedom of the vehicle side slip angle including the roll and the yaw rate are considered. The whole equation of motion is as follows.

Hs: distance between sprung center of gravity and roll center hrs: distance between roll center and ground I: yawing moment Kf: cornering power of front tire Kr: cornering power of rear tire Ms: sprung weight M: Gross vehicle weight Mu: Unsprung weight kfai: Roll rigidity lf: Distance between front axle and center of gravity position lr: Distance between rear axle and center of gravity position V: Vehicle speed β: Lateral sliding angle γ: Yaw rate δ: Steering angle φ: Roll As a corner

[0039]

(Equation 1) Focusing on the roll, expanding it as a transfer function of the roll with respect to the steering angle input,

[0040]

(Equation 2) Becomes However,

[0041]

(Equation 3) It is. Equation (1) is

[0042]

(Equation 4) Becomes

Here, an AR model obtained by applying the AR method to input and output of data obtained from an actual vehicle is generally as follows.

[0044]

(Equation 5) If this is converted into a continuous system and the actual vehicle moves with the degree of freedom as described in the theoretical equation, the order of the obtained transfer function matches the theoretical equation (2). Therefore, equation (2)
Using the fact that the coefficients of the transfer function s in equation (3) match each other as a constraint condition, the following holds. When the coefficient of the term of s ² and e ₂ the height of the center of gravity (hs) is a specification of the functions involved in e ₂ and the vehicle. That is, if the vehicle specifications and the transfer function coefficient e ₂ are known, the height of the center of gravity can be derived, and as shown in FIG.

[0045]

(Equation 6) become that way.

FIG. 6 is a diagram showing a method of statically measuring the height of the center of gravity. As a method of statically measuring the height of the center of gravity, there is a method of FIG. 6 described in JIS security standards and the like. In this case, using a medium-sized truck, an equilibrium state in which a concrete load is directly mounted on the carrier, and The height of the center of gravity of each of the two specifications and the empty car, which are mounted in a so-called high-load state, mounted on a special frame, was measured and set to the true value.
That is, hs = (W · Lr−Wf · L) / Wtanα, where W: Gross weight of vehicle body Wf: Weight applied to front wheels L: Distance from front wheels to rear wheels Lr: Distance from center of gravity position to rear wheels α: Incline Calculate as angle. Next, under these conditions, the vehicle travels on a general road along a normal flow, and the steering angle,
Roll rate and vehicle speed were measured.

FIG. 7 shows the state of the height of the center of gravity estimated by sampling the roll behavior during running. The horizontal axis indicates time, and the vertical axis indicates the height of the center of gravity. The height of the center of gravity constantly fluctuates, and if the collected data is subjected to the theoretical processing as it is, it indicates that there is a problem. FIG. 8 is a diagram illustrating the relationship between the yaw rate, the roll angle, and the steering angle. In FIG. 8A, the steering angle is plotted on the horizontal axis, and the yaw rate is plotted on the vertical axis.
In (b), the roll angles are respectively set on the vertical axis. This is due to the fact that the roll rate is generally more susceptible to the cant and unevenness of the road surface than the yaw rate with respect to the steering input, and the correlation with the steering input is low as shown in FIG.

(Second Embodiment) In such a situation,
To accurately extract the response component of the roll to steering,
As shown in steps S1 to S4 shown in FIG. 9, continuous preprocessing is performed and input to the calculation system for estimating the center of gravity is taken into consideration.

FIG. 11 is a diagram showing a zero point drift due to an error of the measuring instrument. Time is plotted on the horizontal axis and roll rate is plotted on the vertical axis. The roll rate sensor 60, which is a roll rate measuring device shown in FIGS. 22 and 23, includes an error, and causes a zero point drift as shown in FIG. Therefore, the roll rate input needs to prevent the influence of the zero drift of the measuring instrument.

FIG. 12 is a diagram showing the situation of zero point correction using the median value. In FIG. 12A, the horizontal axis represents time,
The vertical axis shows the roll rate. In FIG. 12B, the roll rate is plotted on the horizontal axis, and the frequency is plotted on the vertical axis. In the second embodiment of the present invention, as shown in FIG. 12, the cumulative average value of the measurement signal is treated as a zero point.

Further, in order to increase the correspondence of low-rate behavior due to steering, a steering input of a certain magnitude and speed is used as a trigger, and an appropriate section adapted to the input is sampled to improve the consistency of input and output.

FIG. 13 is a diagram showing a conventional steering angle and low rate sampling. Figure 1 shows the time on the horizontal axis.
3A shows the steering angle on the vertical axis, and FIG. 13B shows the low rate on the vertical axis. Conventionally, the sampling interval is fixed as shown in FIG. 13, but this may cause a loss of necessary data. In the example of FIG. 13, in FIG. 13A, the roll rate of a portion marked with a circle where steering has been performed appears slightly after the steering is actually performed. However, in FIG.
The roll rate of the portion marked with a circle in which the steering in (a) is performed appears after the sampling has already been completed. As a result, the roll rate of the portion marked with a circle in which the steering operation is performed in FIG. 13A is not taken in as data, and high-precision sampling cannot be performed.

FIG. 14 is a diagram showing the sampling of the steering angle and the low rate according to the second embodiment of the present invention. Time is plotted on the horizontal axis, FIG. 14A shows the steering angle on the vertical axis, and FIG. 14B shows the low rate on the vertical axis. In the second embodiment of the present invention, in order to solve the problem shown in FIG.
As shown in FIGS. 4 (a) and (b), a point where both the steering angle and the roll angle are zero is set as a start point and an end point, and a section in which 500 or more data exist between them is sampled.

FIG. 15 is a diagram showing characteristics of the bandpass filter according to the second embodiment of the present invention. FIG. 15A shows time on the horizontal axis and roll rate on the vertical axis. In FIG. 15B, the horizontal axis indicates time, and the vertical axis indicates roll angle. FIG.
In (c), the horizontal axis represents time, and the vertical axis represents the steering angle. FIG.
5 (d) shows time on the horizontal axis and roll angle on the vertical axis.
In FIG. 15E, the horizontal axis represents time, and the vertical axis represents the steering angle. In FIG. 15F, the horizontal axis represents time, and the vertical axis represents roll angle. In FIG. 15G, the horizontal axis represents frequency, and the vertical axis represents power spectrum density.

As shown in FIGS. 15 (c), (d), (e), and (f), the roll rate is sensitive to irregularities on the road surface and to left and right swings such as diagonal joints in a high frequency range. On the other hand, FIG.
As shown in FIGS. 5 (a) and 5 (b), in a low frequency range, an integration error occurs when a vehicle body shake caused by a road surface cant or rutted road is integrated as a roll. In order to prevent these effects, the sensitivity to the steering range is increased by using a band-pass filter to discard both the low frequency on which the integration error rides and the high frequency on which disturbance due to irregular road surface rides.

After performing these processes, as shown in step S4 of FIG. 9, the transfer function of one input and one output is obtained by the AR method to derive the height of the center of gravity. In the present invention the second embodiment, characterized by deriving the height of the center of gravity by using the coefficient e ₁ of the s term. This is because the coefficient e ₁ is more stable than the coefficient e ₂ of the first embodiment of the present invention. Assuming that the coefficient of the term of s is e ₁ , the height of the center of gravity (hs) is a function of e ₁ and various parameters related to the vehicle. That it is, can be derived centroid height Knowing coefficient e ₁ of the specification and the transfer function of the vehicle, as shown in FIG. 10,

[0057]

(Equation 7) become that way.

(Summary of Embodiment) FIG. 16 is a diagram showing the result of estimating the height of the center of gravity of the first embodiment of the present invention. FIG. 17 is a diagram showing the result of estimating the height of the center of gravity of the second embodiment of the present invention. FIG.
17 and 17, the horizontal axis represents time, and the vertical axis represents the height of the center of gravity. According to the first embodiment of the present invention, the height of the center of gravity, which can be conventionally estimated only statically, can now be estimated in real time. However, as shown in FIG. 16, the estimated value has a large error as compared with the true value. Therefore, in the second embodiment of the present invention, steps S1 to S1 shown in FIG.
By executing S4, it can be seen that the estimated value and the true value dramatically match as shown in FIG.

The following is an example of analysis. FIG. 18 is a diagram showing an example of analysis on a general road. FIG. 18 shows time on the horizontal axis, and FIG. 18A shows the steering angle on the vertical axis.
18B shows the roll rate on the vertical axis, and FIG. 18C shows the speed on the vertical axis. Further, the example of FIG. 4 is used as an example in the test course. FIG. 19 is a diagram showing an estimation result of the height of the center of gravity on a test course and a general road. The horizontal axis represents the test course and the general roads a and b, and the vertical axis represents the height of the center of gravity.

The arrow part (← →) in FIG. 18 is a part used for obtaining the transfer function. The estimation can be performed when the correlation between the steering angle input and the low rate is sufficient and the s / n ratio is high (part a).

On the other hand, when the input / output is not sufficient or when the change in the speed is large (part b), a value different from the true value is calculated as the estimation result. As described above, a high s / n ratio and a small change in speed are preconditions necessary for estimation.

FIG. 20 shows an example of calculating the height of the center of gravity of a vehicle having a different height of the center of gravity by changing the loading conditions under these preconditions. FIG. 20 is a diagram showing the estimation results of the height of the center of gravity of an empty vehicle, a flat load, and a heavy load. The horizontal axis indicates empty, flat, and height, and the vertical axis indicates the height of the center of gravity. As can be seen from FIG. 20, the difference in the height of the center of gravity depending on the packing style has been detected, and the tendencies match well.

[0063]

As described above, according to the present invention,
An attitude control device suitable for a large vehicle, particularly a commercial vehicle, can be realized. It is possible to realize a posture control device for adapting to a large vehicle in which behavior data includes many low frequency components. An attitude control device for adapting to a vehicle in which the state of a load or a passenger changes can be realized. Even if the state of the cargo or the passenger changes, it is possible to realize a posture control device in which the vehicle model automatically follows. It is possible to prevent a large vehicle from deviating from the traveling lane and to prevent rollover by driving control that exceeds the characteristics of the vehicle. The height of the center of gravity of the vehicle can be estimated in real time. The control accuracy of the vehicle attitude control device can be improved.

[Brief description of the drawings]

FIG. 1 is a flowchart showing the procedure of a first embodiment of the present invention.

FIG. 2 is a block diagram showing the procedure of the first embodiment of the present invention.

FIG. 3 is a diagram showing the motion characteristics of a vehicle.

FIG. 4 is a diagram showing the relationship between the height of the center of gravity and the roll rate.

FIG. 5 is a diagram showing a dynamic model used in the embodiment of the present invention.

FIG. 6 is a diagram showing a method for statically measuring the height of the center of gravity.

FIG. 7 is a diagram showing the state of the center of gravity height estimated by sampling the roll behavior during traveling.

FIG. 8 is a diagram showing a relationship between a yaw rate, a roll angle, and a steering angle.

FIG. 9 is a flowchart showing the procedure of the second embodiment of the present invention.

FIG. 10 is a block diagram showing the procedure of a second embodiment of the present invention.

FIG. 11 is a diagram showing a zero point drift due to an error of a measuring instrument.

FIG. 12 is a diagram showing a state of zero point correction using a median value.

FIG. 13 is a diagram showing a conventional steering angle and low rate sampling.

FIG. 14 is a diagram showing steering angle and low rate sampling according to the second embodiment of the present invention.

FIG. 15 is a diagram showing characteristics of the bandpass filter according to the second embodiment of the present invention.

FIG. 16 is a diagram showing a center-of-gravity height estimation result of the first embodiment of the present invention.

FIG. 17 is a diagram showing a center-of-gravity height estimation result according to the second embodiment of the present invention.

FIG. 18 is a diagram showing an example of analysis on a general road.

FIG. 19 is a diagram showing estimation results of the height of the center of gravity on a test course and a general road.

FIG. 20 is a diagram showing estimation results of the height of the center of gravity of an empty vehicle, a flat load, and a heavy load.

FIG. 21 is a diagram showing an example of the overall configuration of a conventional attitude control.

FIG. 22 is a system configuration diagram of a conventional attitude control device.

FIG. 23 is a perspective view showing an example of mounting each sensor on a vehicle.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 vehicle 2 attitude control device 3 vehicle stabilization control device (VSC) 4 electronic control braking device (EBS) 5 observer 6 numerical model 7 calculation means 8 evaluation means 9 control amount calculation means 11 sensors 51 control device 52 yaw rate sensor 53 side Direction acceleration sensor 54 Wheel 55 Wheel rotation sensor 56 Brake booster actuator 57 Brake pressure sensor 58 Steering handle 59 Steering angle sensor 60 Roll rate sensor 61 Forward / backward acceleration sensor 62 Governor 63 Governor sensor S1 to S4 Step

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G01C 5/00 G01C 5/00 Z // B62D 101: 00 103: 00 105: 00 109: 00 111: 00 113: 00 131: 00 137: 00

Claims (4)

[Claims] 1. A transfer function of a dynamic model having a degree of freedom including a roll with respect to a steering angle input by a driver during traveling,
Means for deriving the height of the center of gravity assuming that the coefficients of the respective orders with the roll transfer function with respect to the steering angle obtained by using the AR method (autoregression method) from data collected from the actual vehicle are equal to each other. Calculation device for estimating the height of the center of gravity of the vehicle. 2. The vehicle according to claim 1, further comprising a vehicle response calculation circuit automatically updated in real time in a running state by an auto-regression method (AR method). The steering angle input by the function δ of the differential operator s
(S), and when a roll generated in the vehicle by the steering angle is a function φ (s) of the differential operator s, a transfer function of the roll with respect to the steering angle (φ (s) / δ (s))
Represents the value hs · f (s) calculated from the equation of motion of the vehicle having the center of gravity height hs as a quadratic expression of the differential operator s, while transmitting the roll to the steering angle calculated by the arithmetic circuit. The function (φ (s) / δ (s)) is expressed as a quadratic expression of the differential operator s, and the center of gravity is calculated by an equation in which the coefficients of the respective order terms of the quadratic expressions of the two differential operators s are equal to each other. 2. The apparatus for estimating the height of the center of gravity of a vehicle according to claim 1, further comprising means for estimating the height hs. 3. A calculation method for estimating the height of the center of gravity of the vehicle according to claim 1, further comprising means for preferentially adopting the height of the center of gravity hs obtained by an equation in which the coefficients of the first-order terms of the differential operator s are equal to each other. apparatus. 4. The means for estimating includes: a means for performing a zero correction using a median value for a value of a steering angle to be inputted and a value of a measured roll angle; Means for setting the time when the value of the roll angle becomes zero by the zero point correction as a start point and an end point, and sampling between the start point and the end point; and a band pass through which output data of the sampling means passes. 3. The apparatus for estimating the height of the center of gravity of a vehicle according to claim 2, further comprising a filter.