JP2002114138A - Vehicular speed information arithmetic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular speed information arithmetic device that can more precisely detect speed information such as vehicle body speed from wheel rotating speed. SOLUTION: Wheels 12, 14, 16 and 18 have respective speed sensors 20, 22, 24 and 26. The output of each sensor 20, 22, 24, 26 is inputted into a rotation signal processing part 10a in an ECU 10 for controlling the state of vehicle operation. The rotation signal processing part 10a detects the rotating direction and rotating speed of each wheel 12, 14, 16, 18. The operation of an average driving wheel speed from the rotation information in consideration of, for example, the rotating directions of both driving wheels 16 and 18 can produce a more precise estimate of vehicle body speed and thus an estimate of engine driving force. The use of the speed information improves the controllability of traction control, ABS control and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle speed information calculation device for calculating speed information including a vehicle speed necessary for controlling the operation state of a vehicle.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 9-309352 discloses a technique in which a rotational speed sensor provided for each drive wheel detects the average speed of the drive wheels of each drive wheel and estimates the vehicle speed from the average speed of the drive wheels. Is disclosed.

[0003]

However, in the above-described apparatus, since the rotation direction of the wheels is not taken into consideration, when any of the driving wheels is rotating in reverse, the vehicle speed or the rotation state of the driving wheels is not considered. May not be accurately detected, and the running state of the vehicle may not be properly controlled.

[0004] For example, consider the case where the vehicle body slips backward while climbing a hill. As an example of such a case, one of the drive wheels on the road surface with a high friction coefficient reverses with the slip of the vehicle body, and the other drive wheel on the road surface with a low friction coefficient among the drive wheels is There may be a case where the wheel is idling at the normal rotation due to the operation of the differential gear.

In such a case, the rotational speed sensor incorporated in the conventional device does not consider the rotational direction, so that the vehicle speed is the average of the absolute values of the respective drive wheel speeds, and the speed of the vehicle is estimated. Is far away from reality.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a vehicle speed information calculation device capable of detecting speed information such as a vehicle speed more accurately based on the rotation speed of wheels.

[0007]

In order to solve the above-mentioned problems, a vehicular speed information calculating device according to the present invention comprises at least one speed information calculating device.
In a vehicle speed information calculation device that calculates predetermined speed information based on a rotation speed of one drive wheel and a rotation speed of another wheel, the rotation speed and the rotation direction information of the at least one drive wheel and the other wheel are used. The predetermined speed information is calculated based on the calculated speed information.

In this case, the predetermined speed information is calculated based on the rotation speed and the rotation direction information of the at least one drive wheel and the other wheel, so that the speed information can be calculated in consideration of the rotation direction of the wheel. That is, even when there is a wheel that is rotating in reverse, it is possible to reduce the calculation error of the speed information.

In the above arithmetic device, the predetermined speed information may be a driving wheel average speed.

In the above arithmetic device, the predetermined speed information may be a rotation speed of a propeller shaft.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a vehicle speed information calculation apparatus according to an embodiment of the present invention.

FIG. 1 is a diagram conceptually illustrating the configuration of a vehicle incorporating the vehicle speed information calculation device of the embodiment. This vehicle has a front right wheel 12, a front left wheel 1
4, a rear right wheel 16 and a rear left wheel 18. The driving force from the power source 4 including the engine and the transmission is transmitted to the right rear wheel 16 and the rear left wheel 18, which are the driving wheels, via the propeller shaft 6, the differential 8, and the pair of axles 9, 9. You.

This vehicle is provided with a brake pedal 30 for a driver to perform a braking operation. The master cylinder 32 connected to the brake pedal 30
A brake fluid pressure corresponding to the amount of depression of the brake pedal 30 is generated. The brake fluid pressure from the master cylinder 32 is applied to each of the wheels 12, 14, 1 via an actuator 34.
The power is transmitted to a front right wheel cylinder 36, a front left wheel cylinder 38, a rear right wheel cylinder 40, and a rear left wheel cylinder 42 provided on the wheels 6 and 18, respectively.

An accelerator pedal 50 is provided near the brake pedal 30 for the driver to perform an acceleration operation. The accelerator pedal 50 is connected to the throttle device 51 via a wire, and can adjust the engine output according to the amount of depression of the accelerator pedal 50.

Each of the wheels 12, 14, 16, 18 is provided with a front right speed sensor 20, a front left speed sensor 22, a rear right speed sensor 24, and a rear left speed sensor 26, respectively. Each sensor 20, 2
The outputs of 2, 24 and 26 are input to an electronic control unit (hereinafter referred to as ECU) 10 for controlling the operation state of the vehicle.

Each speed sensor 20, 22, 24, 26 provided on each wheel 12, 14, 16, 18 is connected to the
Detection for detecting a signal in accordance with passage of rotors 20a, 22a, 24a, and 26a, which are annular rotating members that rotate together with 14, 16, and 18, and detection portions provided on these rotors 20a, 22a, 24a, and 26a It comprises magnetic sensor units 20b, 22b, 24b and 26b as means.

Each rotor 20a, 22a, 24a, 26a
The detected portion formed on the rotor may be, for example, a protrusion made of a magnetic material periodically formed on the outer periphery of the rotor.
Magnetic sensor units 20b, 22b, 24b, 26b
Consists of a pair of Hall elements, a semiconductor magnetic sensor such as an MR element, and a signal processing circuit arranged in close proximity, and detects the passage of a protrusion or the like as a small change in the magnetic field,
It forms a signal of a suitable type for transmission to the ECU 10.

The ECU 10 includes sensors 20, 22, 2,
A rotation signal processing unit 10a that receives information from the signals from the rotation signal processing unit 4 and 26 and outputs information about the rotation speed and the rotation direction; A traction control (TC) computer 10c, an anti-lock brake system (ABS) computer 10b, and a vehicle stability control (VSC) computer 10d. Here, the TC computer 10b
Prevents the idle rotation of the drive wheels by using information output from the rotation signal processing unit 10a. Further, the ABS computer 10c controls the braking of the vehicle using information output from the rotation signal processing unit 10a and the like. In addition, the VSC computer 10d controls the posture and operation of the vehicle when turning based on information from the rotation signal processing unit 10a and the yaw rate sensor 11.

Based on the detection signals output from the magnetic sensor units 20b, 22b, 24b, and 26b, the rotation signal processing unit 10a determines not only the rotation speeds of the wheels 12, 14, 16, and 18 but also the rotation speeds of these wheels. Detect direction.

FIG. 2 is a timing chart for explaining the principle of detecting the rotation speed and the rotation direction using the magnetic sensor unit 20b. FIG. 2A shows an output signal from one element, and FIG. 2B shows an output signal from the other element.
By sequentially detecting t2 and t3, the rotation speed of the wheel 12 can be detected, and the rotation direction of the wheel 12 can be detected based on the phase difference between the two pulses.

FIG. 3 is a timing chart for explaining specific outputs of the magnetic sensor unit 20b and the like. FIG.
(A) shows an output signal of the magnetic sensor unit 20b. The pulse rising interval corresponds to the rotation speed of the wheel 12, and the pulse level corresponds to the rotation direction of the wheel 12. FIG. 3B shows a detection result of the rotation direction of the wheel 12.

Returning to FIG. 1, a TC computer 10b provided in the ECU 10 outputs a control signal to the throttle device 51 based on information from the rotation signal processing unit 10a and the like, and a power source separately from the accelerator pedal 50. 4 to adjust the amount of fuel supplied to the engine and perform traction control when the vehicle is accelerated. Therefore, the TC computer 10b
Are a CPU that executes a program, a RAM that stores the program and data,
It has a storage device such as an OM and an interface for exchanging data with the rotation signal processing unit 10a and the throttle device 51. Note that the TC computer 10b, the accelerator pedal 50, the throttle device 51, and the like constitute a TC system.

ABS computer 1 provided in ECU 10
0c is based on information from the rotation signal processing unit 10a and the like,
By outputting a control signal to the actuator 34 and controlling the hydraulic pressure of each of the wheel cylinders 36, 38, 40, and 42 provided on each of the wheels 12, 14, 16, and 18, ABS control is performed when the vehicle is braked. Perform This A
The BS computer 10c also includes a CPU, a storage device, an interface, and the like. The ABS computer 10
c, the brake pedal 30, the actuator 34, the wheel cylinders 36, 38, 40, and 42 constitute an ABS system.

VSC computer 1 provided in ECU 10
0d is the rotation signal processing unit 10a, the yaw rate sensor 11
A control signal is output to the actuator 34 on the basis of information from each of the wheel cylinders 36, 38, 40, 42 provided on the wheels 12, 14, 16, 18.
By controlling the hydraulic pressure of the vehicle, yaw control is performed when the vehicle turns. This VSC computer 10c has a CP
U, a storage device, an interface, and the like. Note that V
SC computer 10d, yaw rate sensor 11, actuator 34, wheel cylinders 36, 38, 40,
42 and the like constitute a VSC system.

The operation of the apparatus shown in FIG. 1 will be described below. When the driver operates the accelerator pedal 50 or the brake pedal 3
By appropriately operating a steering wheel (not shown) or the like, the vehicle takes various running states such as accelerating, decelerating, and turning. At this time, the rotation signal processing unit 10a constantly detects the rotation speed and rotation direction of each wheel 12, 14, 16, 18 based on the detection signal from each magnetic sensor unit 20b, 22b, 24b, 26b. Information is sequentially output to each of the computers 10b, 10c, and 10d.

The TC computer 10b obtains information on the wheel speed and the rotation direction from the rotation signal processing unit 10a obtained as described above, and the driving wheels 16, 1
Based on the average speed of the drive wheel 8 and the number of revolutions of the propeller shaft 6, the idling of the driving wheels 16 and 18 and the degree thereof are detected, the operation of the throttle device 51 is controlled, and the idling of the driving wheels 16 and 18 is effectively performed. To prevent.

The ABS computer 10c detects slips of the wheels 12, 14, 16, and 18 based on the information on the wheel speed and the rotation direction from the rotation signal processing unit 10a, and performs a normal brake mode, a pressure reduction mode, and a hold mode. , And the pressure increase mode is appropriately switched to enable safe and quick braking of the vehicle.

The VSC computer 10d detects the occurrence of understeer or oversteer during cornering by using information from the rotation signal processing unit 10a and the yaw rate sensor 11, controls the operation of the actuator 34 and the like, and controls the operation of the outer ring or the inner ring. Apply proper braking to keep the vehicle stable.

A specific example of the average driving wheel speed calculated by the TC computer 10b will be described below. When the differential 8 is an open differential, the speed conversion value of the number of revolutions of the propeller shaft 6 (hereinafter, the speed of the propeller shaft)
Is 5 km / h, the wheel speed of both drive wheels 16 and 18 is usually 5 km / h from the relation of the propeller shaft speed = (right wheel speed + left wheel speed) / 2.

Here, when starting on a slope, the rear right wheel 16
However, consider a case in which the vehicle is running on a road surface with low frictional resistance such as ice and the driving force is applied, and the vehicle body as a whole slips down a slope. Assuming that the rear left wheel 18 is on the road surface with high frictional resistance and reverses with the rearward movement of the vehicle body, the speed of the propeller shaft is 5 km / h, the rear left wheel 18 is -5 km / h, Right wheel 16 is 15
km / h, and the average driving wheel speed is 5 km / h.
On the other hand, if the average driving wheel speed is obtained without considering the rotation direction of the driving wheels as in the related art, the average driving wheel speed is 10 km / h as an average of the absolute value, which is different from reality.

When the average driving wheel speed is calculated in consideration of the rotational directions of the driving wheels 16 and 18 as in the present embodiment, the estimation of the vehicle body speed becomes more accurate, and the driving force of the engine can be estimated. By using these speed information,
Controllability such as traction control, ABS control, and yaw control (VSC control) is improved.

Although the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment.
For example, in the above-described embodiment, the ECU 10 is separated into the rotation signal processing unit 10a, the TC computer 10b, the ABS computer 10c, and the VSC computer 10d for each function, but these arithmetic processing functions are realized by one computer. Can also.

The rotation speed and rotation direction detected by the rotation signal processing unit 10a can be used not only for calculating the average driving wheel speed but also for calculating the rotation speed of the propeller shaft 6. In this case, without providing a rotation speed sensor on the propeller shaft 6, the output signal of the rotation signal processing unit 10a can be used to accurately calculate the speed of the propeller shaft and its converted value. The rotation speed of the propeller shaft can be used for controlling the engine and the transmission.

Although the above-described embodiment is a two-wheel drive vehicle, the present invention can be applied to a four-wheel drive vehicle.

[0035]

According to the vehicle speed information calculation device of the present invention, the predetermined speed information is calculated based on the rotation speed and the rotation direction information of at least one driving wheel and the other wheels. Can be calculated in consideration of the vehicle speed, and the traveling state of the vehicle can be more appropriately controlled.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a vehicle incorporating a vehicle speed information calculation device according to an embodiment.

FIGS. 2A and 2B are timing charts for explaining a principle of detecting a rotation speed and a rotation direction.

FIG. 3A is a timing chart illustrating a specific output of a magnetic sensor unit, and FIG. 3B is a detection result of a rotation direction of a wheel.

[Explanation of symbols]

4 power source, 6 propeller shaft, 8 differential, 10 ECU, 10a rotation signal processing unit, 10
b: TC computer, 10b: ABS computer,
10c: VSC computer, 11: yaw rate sensor, 12, 14, 16, 18 ... wheels, 20, 22, 24, 26
... speed sensors, 20a, 22a, 24a, 26a ... rotors, 20b, 22b, 24b, 26b ... magnetic sensor units, 30 ... brake pedals, 32 ... master cylinders, 34 ... actuators, 36, 38, 40, 42 ... wheel cylinders , 50 ... accelerator pedal, 51 ... throttle device.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Noritaka Yamada 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Automobile Co., Ltd. (72) Inventor Toshinobu 2-1, Asahimachi, Kariya City, Aichi Prefecture Aisin Seiki Co., Ltd. (72) Inventor Yasuhito Ishida 2-1-1 Asahi-cho, Kariya-shi, Aichi F-term (reference) in Aisin Seiki Co., Ltd. 3D046 BB28 BB29 CC02 EE01 HH02 HH36

Claims (3)

[Claims] 1. A vehicular speed information calculation device for calculating predetermined speed information based on a rotation speed of at least one drive wheel and a rotation speed of another wheel, wherein the at least one drive wheel and the other wheel A speed information calculation device for a vehicle, wherein the predetermined speed information is calculated based on rotation speed and rotation direction information. 2. The vehicle speed information calculation device according to claim 1, wherein the predetermined speed information is a driving wheel average speed. 3. The vehicle speed information calculation device according to claim 1, wherein the predetermined speed information is a rotation speed of a propeller shaft.