JP2000019002A - Device for estimating mass of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the measurement of the mass of a vehicle regardless of the type of the vehicle by preparing the relationship between brake fluid pressure and deceleration into a map with the mass of vehicles as parameters, actually measuring and computing fluid pressure and acceleration, and tracing it onto the map. SOLUTION: A device for estimating the mass of a vehicle is provided with a brake pressure sensor 57, a brake pressure computing part 70, an axle rotation sensor 55, an acceleration and deceleration computing part 71, a mass estimation computing part 73, etc. Brake pressure data is inputted to the mass estimation computing part 73 from the brake pressure sensor 57 via the brake pressure computing part 70, and acceleration and deceleration data is inputted to the mass estimation computing part 73 from the axle rotation sensor 55 via the acceleration and deceleration computing part 71. The mass estimation computing part 73 estimates the mass of the vehicle by detecting the state of travelling of the vehicle according to input from the acceleration and deceleration computing part 71, plotting the relationship between brake fluid pressure and deceleration in the case that the vehicle is being decelerated on a map 80 in which the relationship between brake fluid pressure and the deceleration of vehicles is recorded with the mass of vehicles as parameters, and selecting a straight line appropriate to the curve of the plotting.

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 wheel rotation sensor on the wheel to detect the wheel rotation, and if the wheel rotation stops when the brake pressure is large, it will intermittently control the brake pressure as if there was a slip between the wheel and the road surface. is there. 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 is,
From the steering angle (the steering wheel angle) input by the driver, the course that the driver is going to read is read, and if the vehicle speed is too high for that course, the driver will automatically decelerate without having to depress the brake pedal. This is a device that performs control such as distributing the left and right brake pressures so as not to deviate from the course.

[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, when 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 skidding. 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.

A conventional attitude control device will be described with reference to FIGS. FIG. 4 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 includes a vehicle stabilization control device (VSC) 3 and an electronic control 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.

[0007] 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 supplies 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. 5 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, and is a vehicle stabilization control device that receives a driving operation input of the vehicle and behavior data of the vehicle and calculates and outputs a motion state of the vehicle. (VSC) and control means for providing the vehicle with a correction input for correcting the driving operation input and the disturbance input to a safe side in accordance with the calculation output of the vehicle stabilization control device.

This 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, and the respective detection outputs are connected to a control device 51. Wheel rotation sensors 55 are attached to the front wheels 54f and the rear wheels 54r, respectively, and their detection outputs are also connected to the control device 51.
A brake pressure sensor 57 is attached to the brake booster actuator 56, and its 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. 6 is a perspective view showing an example of mounting each sensor on a vehicle. FIGS. 5 and 6 show a vehicle having a two-axis structure, but in the case of a large vehicle, a three-axis or four-axis structure is used. Further, the attitude control device 2 is also mounted on a connected vehicle constituted by a header side and a trailer side.

In such an ABS and a vehicle attitude stabilizing device (VSC), brake pressure control is an important control element. At this time, the value of the brake pressure is determined by the mass of the vehicle. That is, since the magnitude of the mass is proportional to the magnitude of the inertial force, the magnitude of the mass is also proportional to the magnitude of the brake pressure.

[0011]

As described above, estimating the mass of the vehicle is important for the ABS and the vehicle attitude stabilizing device. The mass of this vehicle varies depending on the amount of cargo or the number of passengers. The brake fluid pressure for brake control must be changed and set accordingly. Conventionally, brake fluid pressure has been adjusted by adjusting how much the brake pedal is depressed according to the feeling of a familiar driver. However, the brake fluid pressure is directly controlled and output as in ABS and vehicle stabilization devices. It is necessary to input the current mass of the vehicle to the control device as a control parameter in advance.

Conventionally, an apparatus for estimating the current vehicle mass by measuring the displacement of a spring that supports the vehicle body with respect to the axle by an axle load sensor has been used. However, since the spring constant is different for each vehicle type, it is necessary to set the constant of the axle load sensor for each vehicle type, which is expensive. Also,
In the case of a tractor, the entire mass cannot be measured only by the tractor-side axle load sensor unless the connected trailers are individually provided with an axle load sensor. Therefore, development of a method or a device for estimating the vehicle mass without using the axle load sensor is desired.

The present invention has been made in view of such a background, and an object of the present invention is to provide a mass estimating apparatus capable of measuring the mass of a vehicle regardless of the type of vehicle. SUMMARY OF THE INVENTION An object of the present invention is to provide a mass estimating apparatus capable of estimating the mass of a connected vehicle including a trailer on a tractor side regardless of a connected trailer.

[0014]

According to the present invention, the relationship between the brake fluid pressure and the deceleration of the vehicle is prepared in a map using the vehicle mass as a parameter, and the brake fluid pressure and the deceleration are measured from a speed sensor. The approximate vehicle mass is estimated by calculating and tracing on the map.

That is, if the brake fluid pressure is plotted on the abscissa and the deceleration by the time derivative of the wheel rotational speed is plotted on the ordinate, many straight lines having different slopes can be drawn on this plane using the mass as a parameter. When the measured value of the brake fluid pressure of the vehicle and the measured value based on the time derivative are plotted on this plane, it is determined which of the many straight lines the curve drawn by the plot approximates. Can be. Thereby, the estimated value of the vehicle mass can be obtained.

Further, before the brake fluid pressure is zero and deceleration due to the time differential value of the wheel rotation speed is observed,
When a gradient is observed by the gradient sensor in the vehicle traveling direction, it is necessary to correct the influence of the gradient.
Further, when the locked state of the wheel is detected even temporarily, the time differential value of the wheel rotational speed becomes inaccurate, and in that case, the output of the estimated value must be invalidated.

That is, the present invention relates to a mass estimating apparatus for a vehicle. The present invention is characterized by a brake pressure sensor for detecting a fluid pressure of a brake, a wheel rotation sensor for detecting a wheel rotation speed, and Means for calculating the acceleration and deceleration of the vehicle by calculating the time differential value of the vehicle speed obtained based on the output of the wheel rotation sensor, and the relationship between the vehicle deceleration and the brake fluid pressure is recorded in advance using the vehicle mass as a parameter. When the time differential value indicates a deceleration state, the deceleration calculated by the calculating means with respect to the brake fluid pressure measured by the brake pressure sensor corresponds to the deceleration characteristic on the map. And a means for estimating the mass to be generated.

The mass estimating means may be a means for plotting the value of the deceleration calculated with respect to the measured fluid pressure over time on the map, and may approximate a curve drawn by the plot. Means for selecting a straight line.

A means for calculating the deceleration of the vehicle, wherein the means for calculating the deceleration includes means for correcting and calculating the deceleration according to the slope measured immediately before deceleration by the slope sensor. Is desirable.

It is preferable that the apparatus further comprises means for invalidating the output of the means for estimating the mass when the wheel rotation sensor indicates a zero value.

[0021]

Embodiments of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of a main part of a vehicle mass estimating apparatus according to an embodiment of the present invention. The vehicle mass estimating device according to the embodiment of the present invention is mounted in a control device 51 shown in FIGS.

The present invention relates to a mass estimating apparatus for a vehicle. The present invention is characterized by a brake pressure sensor 57 for detecting a brake fluid pressure, a wheel rotation sensor 55 for detecting a wheel rotation speed, and Acceleration / deceleration calculation section 71 which is means for calculating the acceleration and deceleration of the vehicle by calculating the time differential value of the vehicle speed obtained based on the output of wheel rotation sensor 55, and the relationship between the deceleration of the vehicle and the brake fluid pressure And a map 80 pre-recorded with the vehicle mass as a parameter, wherein the acceleration / deceleration calculating unit 71 calculates the fluid pressure of the brake measured by the brake pressure sensor 57 when the time differential value indicates a deceleration state. It is provided with a mass estimating calculation unit 73 which is means for estimating a corresponding mass on the map 80 from the characteristics of deceleration.

The mass estimating calculation unit 73 plots the value of the deceleration calculated with respect to the measured fluid pressure over time on the map 80, and selects a straight line approximating the curve drawn by the plot. I do.

A gradient sensor 65 for measuring the gradient of the vehicle
The acceleration / deceleration calculation unit 71 corrects and calculates the deceleration according to the gradient measured immediately before deceleration by the gradient sensor 65.

When the wheel rotation sensor 55 indicates a zero value, the output of the mass estimating calculation unit 73 is invalidated.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a flowchart showing the operation of the mass estimating operation unit 73 according to the embodiment of the present invention. FIG. 3 is a diagram for explaining the map 80 according to the embodiment of the present invention.

The operation of the mass estimating operation unit 73 according to the embodiment of the present invention will be described with reference to FIG. The output of the brake pressure sensor 57 shown in FIG. 1 is taken in by the brake pressure calculation unit 70, and the brake pressure data output from the brake pressure calculation unit 70 is input to the mass estimation calculation unit 73. Further, the output of the wheel rotation sensor 55 is taken in by the acceleration / deceleration calculation unit 71, and the acceleration / deceleration data output from the acceleration / deceleration calculation unit 71 is input to the mass estimation calculation unit 73 (S1).

The mass estimating operation unit 73 includes an acceleration / deceleration operation unit 7
According to the acceleration / deceleration data input from step 1, the traveling state of the vehicle is detected. The acceleration / deceleration calculation unit 71 measures the vehicle speed according to the output of the wheel rotation sensor 55, and further calculates the acceleration or deceleration by differentiating the vehicle speed with time. According to the acceleration / deceleration data of the acceleration / deceleration calculation unit 71, if the vehicle is decelerating (S2), the deceleration value is referred to (S4). At this time, if the output of the wheel rotation sensor 55 temporarily becomes zero, the wheel may be in a slip state and may be locked (S3). The calculation stops. When the deceleration value is referred to without locking the wheels, the relationship between the brake pressure and the deceleration is plotted on the map 80 as shown in FIG. The mass of the vehicle is estimated by selecting a straight line (shown by a broken line) that approximates the curve drawn by this plot (S5). The map 80 shown in FIG. 3 has the brake pressure on the horizontal axis and the deceleration on the vertical axis. The straight line on the map 80 is obtained by an experiment in advance in which the relationship between the brake fluid pressure and the deceleration of the vehicle is determined by using the vehicle mass as a parameter.

When the gradient detecting section 72 detects the gradient by the gradient sensor 65 shown in FIG. 1, the estimated mass value is corrected in consideration of the gradient resistance (S7), and this value is output. (S8). That is, for example, if the uphill slope is compared with a flat ground under the condition that the vehicle is stopped at the same braking distance, the uphill slope requires less brake pressure, so it is necessary to make a correction for this. . Conversely, in the case of a downhill slope, a larger brake pressure is required as compared to a flat ground, and therefore, it is necessary to make a correction for this. When acceleration or deceleration is performed, the output of the gradient sensor during acceleration / deceleration cannot be used because the gradient sensor 65 detects a gradient that rises or falls forward even on a flat ground.

As described above, the mass estimating apparatus of the present invention can estimate the mass of the vehicle by inputting the brake pressure and the deceleration. Therefore, as before,
There is no need to provide different axle load sensors for each model,
Even when it is not clear what kind of vehicle is connected to the trailer side like a connected vehicle, the mass of the entire connected vehicle can be estimated by providing the mass estimating device of the present invention on the tractor side.

[0031]

As described above, according to the present invention,
Since the mass of the vehicle can be estimated by inputting the brake pressure and the deceleration, the mass of the vehicle can be measured regardless of the vehicle type. Further, the mass of the connected vehicle including the trailer can be estimated on the tractor side regardless of the connected trailer.

[Brief description of the drawings]

FIG. 1 is a block diagram of a main part of a vehicle mass estimating apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation of a mass estimation calculation unit according to the embodiment of the present invention.

FIG. 3 is a diagram for explaining a map according to the embodiment of the present invention.

FIG. 4 is a diagram showing an example of the overall configuration of a conventional attitude control.

FIG. 5 is a system configuration diagram of a conventional attitude control device.

FIG. 6 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) 11 sensors 51 control device 52 yaw rate sensor 53 lateral acceleration sensor 54f front wheel 54r rear wheel 55 wheel rotation sensor 56 brake booster Actuator 57 Brake pressure sensor 58 Steering wheel 59 Steering angle sensor 60 Roll rate sensor 61 Front-rear direction acceleration sensor 62 Governor 63 Governor sensor 65 Gradient sensor 70 Brake pressure calculating unit 71 Acceleration / deceleration calculating unit 72 Gradient detecting unit 73 Mass estimation calculating unit 80 Map

Claims (4)

[Claims] 1. A vehicle comprising: a brake pressure sensor for detecting a fluid pressure of a brake; a wheel rotation sensor for detecting a wheel rotation speed; and a time differential value of a vehicle speed obtained based on an output of the wheel rotation sensor. Means for calculating the acceleration and deceleration of the vehicle, and a map in which the relationship between the deceleration of the vehicle and the brake fluid pressure is recorded in advance using the vehicle mass as a parameter, and when the time differential value indicates a deceleration state, the brake pressure sensor A mass estimating device for a vehicle, comprising: means for estimating a corresponding mass on the map from characteristics of deceleration calculated by the means for calculating the fluid pressure of the brake measured by the above. 2. The means for estimating the mass includes: means for plotting a value of a deceleration calculated with respect to a measured fluid pressure over time on the map, and a curve drawn by the plot. Means for selecting a straight line to be approximated. 3. A slope sensor for measuring the slope of the vehicle, wherein the means for calculating the deceleration corrects and calculates the deceleration according to the slope measured immediately before deceleration by the slope sensor. The vehicle mass estimating device according to claim 1 or 2, further comprising: 4. The mass estimating device for a vehicle according to claim 1, further comprising means for invalidating an output of said mass estimating means when said wheel rotation sensor indicates a zero value.