KR20100097908A

KR20100097908A - Rpm sensing method for auto transmission

Info

Publication number: KR20100097908A
Application number: KR1020090016788A
Authority: KR
Inventors: 조명수
Original assignee: 현대 파워텍 주식회사
Priority date: 2009-02-27
Filing date: 2009-02-27
Publication date: 2010-09-06

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission, and more particularly, to a rotation speed measuring method for an automatic transmission that can reduce an error of the rotation speed measured when a low speed rotation is below a predetermined value.

The present invention, judging step of determining whether the rotation speed of the measuring wheel is less than the set value; And a predicted output step of outputting a predicted rotation speed measured by a dynamic model when the rotation speed of the measuring wheel is less than or equal to a set value.

Description

Rotation speed measurement method for automatic transmission {RPM SENSING METHOD FOR AUTO TRANSMISSION}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission, and more particularly, to a rotation speed measuring method for an automatic transmission that can reduce an error due to a decrease in the rotational speed (Resolution) measured during a low speed rotation below a predetermined value.

In general, an automatic transmission for an automobile has a multi-speed gear mechanism connected to a torque converter that receives power from an engine, and hydraulic operation for selecting one of gear stages of the gear shift mechanism according to driving conditions of the vehicle. It consists of a hydraulic control system that supplies the friction elements and the hydraulic pressure required to operate the control valve.

Such an automatic transmission typically performs an appropriate shift stage change according to a driving state of a vehicle while the automatic transmission electronic control device (hereinafter referred to as TCU) exchanges signals with the engine in an automatic transmission period.

1 is a configuration diagram showing a rotation speed measuring device of an automatic transmission according to the prior art.

Referring to FIG. 1, the rotation speed of an automatic transmission according to the related art is calculated by detecting a period of a square wave using a voltage square wave generated from the measuring wheel 10 and the sensor 20.

An example of a formula for calculating the rotation speed from the detected value is the same as that of Formula 1.

[Formula 1]

Revolutions (units per minute) = 1 (unit) / period (msec) * 1000 * 60 / number of projection wheel

As described above, the rotation speed measuring method of the automatic transmission according to the related art is determined by the number of the projections 12 of the measuring wheel 10, and the period of the square waveform is shorter than the minimum unit time (Task Time) of driving the TCU. The rotational speed of the automatic transmission is the average value for all cycles of the corresponding task time.

The rotation speed measuring method for an automatic transmission according to the prior art measures when the driving speed is lower than a predetermined speed because the rotation speed is not calculated constantly for the rotation of a constant measuring wheel when the period of the square wave is longer than the task time of the TCU. There is a problem that the error is large in the number of revolutions of the automatic transmission.

Therefore, there is a need for improvement.

The present invention has been made to solve the above problems, and an object thereof is to provide a rotation speed measuring method for an automatic transmission in which an error of the rotation speed measured when driven at a low speed is reduced.

In order to achieve the above object, the present invention, judging step of determining whether the rotation speed of the measuring wheel is less than the set value; And a predicted output step of outputting a predicted rotation speed measured by a dynamic model when the rotation speed of the measuring wheel is less than or equal to a set value.

In addition, in the determining step of the present invention, if the number of revolutions of the measuring wheel is greater than the set value provides a rotation speed measuring method for an automatic transmission, characterized in that the switching to a measurement output step of outputting the number of revolutions of the measuring wheel measured by the sensor. do.

The rotation speed measuring method for an automatic transmission according to the present invention calculates the predicted rotation speed by a dynamic model, and when the automatic transmission is driven at a low speed below a set value, the predicted rotation speed is determined as the final rotation speed. There is an advantage that can reduce the error caused by the degree of degradation of the generated rotation sensor.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of a rotation speed measuring method for an automatic transmission according to the present invention.

In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of description.

In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to a user's or operator's intention or custom.

Therefore, definitions of these terms should be made based on the contents throughout this specification.

2 is a block diagram illustrating an apparatus for measuring rotation speed for an automatic transmission according to an embodiment of the present invention, and FIG. 3 is a flowchart illustrating a method for measuring rotation speed for an automatic transmission according to an embodiment of the present invention.

2 and 3, the method for measuring the rotation speed for an automatic transmission according to an embodiment of the present invention includes a determination step S10 of determining whether the rotation speed of the measurement wheel is less than or equal to the set value, and the rotation speed of the measurement wheel less than or equal to the set value. And a predictive output step S20 of outputting a predicted rotation speed measured by the back surface dynamics model.

Thus, when the rotation speed measurement of the automatic transmission is started, the rotation speed is calculated according to the number of protrusions of the measuring wheel per unit time input from the sensor 30, and the TCU 50 receives the number of the protrusions of the measuring wheel detected within the unit time. Rotation speed is calculated.

The rotational speed calculated by the TCU 50 is used to control the automatic transmission 70 to perform accurate control, and the formula for calculating the rotational speed from the number of protrusions of the measuring wheel is shown in [Formula 1] and same.

At this time, when the number of revolutions detected by the sensor 30 is less than or equal to the set value, it is switched to the predictive output step S20 of determining the number of revolutions of the measuring wheel by the dynamics model to determine the number of revolutions of the automatic transmission by the dynamics model.

Here, the set value means the minimum value of the rotation speed measurement and the minimum value of the rotation speed measurement is determined by the number of protrusions of the measuring wheel.

The dynamic model used when the automatic transmission performs a low speed drive below a set value is shown in [Formula 2].

[Formula 2]

Where Jt is the moment of inertia, Nt is the turbine speed, Tt is the turbine torque, Ta is the coupling torque, Tr is the release torque, and xa and xr are constants derived from planetary gear kinematics.

In the case of static shifts such as N-D and N-R, [Formula 2] can be expressed in a simple form as shown in [Formula 3].

[Formula 3]

г

,

Where μ is the coefficient of friction, A is the piston area, Fs is the return spring reaction force, n is the number of clutches, eq is the equivalent radius, and Pa is the control pressure of the clutch.

The predicted rotational speed calculated by [Formula 2] and [Formula 3] as described above is output and the automatic transmission is controlled by this output value.

If the number of revolutions of the measuring wheel in the determination step (S10) or more than the set value is converted to the measurement output step (S30) for outputting the number of revolutions of the measuring wheel measured by the sensor 30, the rotation by [Formula 1] described in the prior art The number is determined.

Therefore, when the automatic transmission is driven at a speed higher than the set value, the rotation speed is determined by the data measured by the sensor 30. When the automatic transmission is driven at the speed lower than the set value, the automatic transmission is predicted by the predicted rotation speed by the dynamic model. The rotation speed of is determined.

As a result, the error of the number of revolutions measured at low speed can be reduced, thereby achieving safe control of the automatic transmission. In particular, the rotation for the automatic transmission in which the shifting feeling is improved when the shift generated during stop or low speed driving such as static shifting is performed. It is possible to provide a number measurement method.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and various modifications and equivalent other embodiments are possible to those skilled in the art. Will understand.

In addition, although the rotation speed measuring method of the automatic transmission installed in the vehicle has been described as an example, this is merely exemplary, and the rotation speed measuring method of the present invention may be used in other products other than the vehicle.

Therefore, the true technical protection scope of the present invention will be defined by the claims below.

1 is a block diagram showing a rotation speed measuring device of an automatic transmission according to the prior art.

2 is a block diagram showing an apparatus for measuring rotation speed for an automatic transmission according to an embodiment of the present invention.

3 is a flowchart illustrating a rotation speed measuring method for an automatic transmission according to an embodiment of the present invention.

30 sensor 50 TCU

70: automatic transmission

Claims

A determination step of determining whether the rotation speed of the measuring wheel is equal to or less than a set value; And

And a predicted output step of outputting a predicted rotation speed measured by a dynamic model when the rotation speed of the measuring wheel is less than or equal to a set value.

The method of claim 1,

And in the determining step, the rotation speed of the measuring wheel is set to a measurement output step of outputting the rotation speed of the measuring wheel measured by the sensor.