KR100285451B1 - Device and method for compensating initial duty rate of feedback control in transmission - Google Patents

Abstract

PURPOSE: An initial duty rate compensating apparatus of feedback control and a method thereof are provided to reduce shift shock by feedback controlling properly with correcting the duty rate of a hydraulic pressure valve according to vehicle speed, turbine RPM(Revolution Per Minute) and the output RPM of the transmission in downshifting. CONSTITUTION: An initial duty rate compensating of feedback control is composed of a turbine RPM detecting unit(10) detecting turbine RPM at the input part of a transmission; a vehicle speed detecting unit(20) detecting vehicle speed such as RPM at the output part of the transmission; a transmission control unit(30) connected to output ends of turbine RPM and vehicle speed detecting units to compensate the initial duty rate for feedback control according to changes of turbine RPM and vehicle speed; and a transmission unit(40) connected to the output end of the transmission control unit to operate hydraulic pressure according to the shift signal. The output of the transmission is improved, and shift shock is prevented with controlling the duty rate of the hydraulic valve according to vehicle speed and turbine RPM.

Description

Initial Duty Ratio Correction Device of Feedback Control in Vehicle Shift and Its Method

1 is a block diagram illustrating an initial duty ratio correcting apparatus for feedback control in a vehicle shift according to an exemplary embodiment of the present invention.

2 is a graph showing the rate of change of the turbine speed per hour according to an embodiment of the present invention,

3 is an operation flowchart of a feedback control initial duty rate correction method for shifting a vehicle according to an exemplary embodiment of the present invention.

The present invention relates to a feedback control initial duty rate correction device and a method thereof for shifting a vehicle. More specifically, when downshifting is performed in an automatic shifting vehicle, the feedback is corrected by correcting the initial duty ratio of the hydraulic valve according to the vehicle speed of the traveling vehicle. The present invention relates to a feedback control initial duty ratio correction device and a method for shifting a vehicle for performing control.

The shift control apparatus of the conventional automatic transmission vehicle corrects the duty ratio of the hydraulic valve according to the input rotational speed of the transmission, that is, the turbine rotational speed, at the time of downshift or upshift, so that the clutch is smoothly engaged. (feedback) Control is being performed.

At this time, the initial duty ratio for generating the initial hydraulic pressure according to the feedback control plays an important role in the shift control performance.

However, in the related art, since the initial duty ratio of the feedback control is fixed, a deviation occurs due to the gap change between the clutches and the wear of the vehicle according to the driving of the vehicle, so that the smooth shifting operation is not performed accordingly, thereby reducing the shifting feeling. Occurs.

In order to solve the above problems, a technique for correcting the initial duty rate for feedback control according to the change rate of the turbine speed and the change of vehicle speed is disclosed in Korean Patent Application No. 95-66763 (filed December 29, 1995). It is described in "Initial Duty Ratio Correction Apparatus and Method of Feedback Control in a 4 → 3 Speed Shift".

However, in the above-described conventional technology, since the set value for determining the run-up state and the tie-up state of the vehicle is fixed constantly regardless of the vehicle speed according to the change rate of the turbine speed, There is a problem in that misjudgment occurs when the vehicle speed is high speed and low speed.

In other words, it is determined that the measured turbine speed change rate is greater than or equal to the set value and the current vehicle state is in the run-up state. However, when the running vehicle is actually high speed, the run-up may occur even when the turbine speed change rate is less than or equal to the set value. Therefore, accurate determination of the run-up and tie-up states is not made.

In addition, when the turbine rotational speed increases and then suddenly increases above the target rotational speed, there is a problem that proper feedback control is not performed by determining this as a run-up state even though the state corresponds to a severe tie-up state.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, by correcting the initial duty ratio of a hydraulic valve according to the relationship between the vehicle speed of a traveling vehicle and the turbine speed and the output rotation speed of the transmission during downshifting in an automatic transmission vehicle. The present invention provides a feedback control initial duty rate correction device and a method for shifting a vehicle to improve output of a transmission by performing more appropriate feedback control according to a vehicle driving state.

The configuration of the present invention for achieving the above object, the turbine rotation speed detection means for detecting the turbine rotation speed which is the input rotational speed of the transmission and outputs an electrical signal corresponding thereto; Output rotation speed sensing means for sensing an output rotation speed of the transmission and outputting an electrical signal corresponding thereto; And a shift control means for correcting the initial duty ratio for feedback control in accordance with the change rate of the turbine rotational speed and the vehicle speed at the time of down shift.

Another aspect of the present invention for achieving the above object comprises the steps of measuring the turbine speed change rate by sampling the turbine speed output from the turbine speed sensing means at a predetermined time during downshift; Setting a duty ratio correction amount for increasing or decreasing hydraulic pressure according to the measured turbine speed change rate and the vehicle speed; Calculating an initial duty ratio for feedback control by adding the correction amount set according to the turbine rotation rate change rate to the basic duty ratio at high speed when the detected vehicle speed is faster than the set vehicle speed; When the detected vehicle speed is slower than the set vehicle speed, the initial duty ratio for feedback control is calculated by adding the correction amount set according to the turbine rotation speed change rate to the basic duty ratio at the low speed.

By the above configuration, the most preferred embodiment that can be easily carried out by those skilled in the art with reference to the present invention will be described in detail with reference to the accompanying drawings.

1 is a corner block diagram of an apparatus for correcting an initial duty rate of feedback control during vehicle shifting according to an embodiment of the present invention, and FIG. 2 is a graph showing a rate of change of turbine revolutions per hour according to an embodiment of the present invention. FIG. Is an operation flowchart of a feedback control initial duty ratio correction method in shifting a vehicle according to an exemplary embodiment of the present invention.

As shown in FIG. 1, the configuration of the initial duty ratio correction device for feedback control during vehicle shifting according to an embodiment of the present invention includes: turbine rotation speed sensing for sensing turbine rotation speed, which is an input side of the transmission output from the torque converter; It is connected to the vehicle speed detecting unit 20 for detecting the vehicle speed which is the output side rotation speed of the transmission unit 10 and the transmission, and the feedback rate according to the change rate and the vehicle speed of the turbine rotation speed detected by the output terminals of the detection units 10 and 20. The shift control unit 30 corrects the initial duty ratio, and the shift unit 40 connected to the output terminal of the shift control unit 30 to operate the hydraulic pressure with a corresponding friction element to perform a shift operation.

The shifting unit 40 performs shifting by a plurality of solenoid valves whose operating states are changed according to a signal output from the shift control unit 30 and hydraulic pressure applied according to an operating state of the pressure regulating solenoid valve. Friction elements are also included.

The operation of the feedback control initial duty rate correction device during vehicle shift according to the embodiment of the present invention by the above configuration is as follows.

When the vehicle travels at three speeds and is downshifted at two speeds, the shift control unit 30 branches to the routine shown in FIG. 3 and performs an initial duty rate correction operation according to feedback control as follows. .

The shift control unit 30 measures the turbine rotation speed change rate by sampling the signal output from the turbine rotation speed detection unit 10 at predetermined times as the vehicle travels (S110).

In the present invention, in order to adjust the hydraulic pressure to achieve a smooth shift in accordance with the rate of change of the turbine speed, as shown in the accompanying Figure 2 divided into a plurality of sections for measuring the turbine speed change rate, and then the turbine in each section The speed change rate is measured, and the shift control unit calculates and controls the duty rate of the solenoid valve so as to perform a smooth shift operation according to the measured turbine speed change rate and the target turbine speed change rate.

In other words, after dividing the sections into a plurality of sections (A, B) according to the increase in the turbine rotation speed, that is, the arrival rate to the target turbine rotation speed, the torque as the downshift operation is performed from three speeds to two speeds in each section. The turbine rotation rate, which is the input torque output from the converter, is measured and stored, and the value is stored in the corresponding address of many memories, not shown.

The target turbine rotation rate change rate as mentioned above represents the ideal turbine rotation rate change rate which can improve a shift feeling maximally at the time of a current shift.

In order to calculate the duty ratio for adjusting the hydraulic pressure in accordance with the occurrence of the downshift from the third speed to the second speed, the shift control unit 30 first has a minimum turbine speed having a minimum value among the turbine speed change rates measured at the first set value. Calculated by multiplying the first set value by the change rate dNt _min and the first set change rate for determining whether an interlock phenomenon occurs, that is, the target turbine rotation rate change rate Ni in the first set period. The value is compared and determined (S120).

The first set value according to the embodiment of the present invention is a variable for limiting the minimum allowable turbine rotation rate change rate in the first set section, and the target turbine rotation of the first set section when downshifting from three speeds to two speeds. An arbitrary value is multiplied by the number change rate, and a plurality of simulated shift experiments are performed according to the value, and then the value multiplied immediately before the interlock phenomenon occurs is set as the first set value. According to an embodiment of the present invention, the first set value is about 0.7.

When the minimum turbine speed change rate dNt _min measured in the first setting section is smaller than the first setting change rate, an interlock phenomenon may occur in which the clutch is fastened because the hydraulic pressure acting as a friction element is too strong. In operation S130, the correction amount b is increased by a predetermined value (0.4%) so as to increase the hydraulic pressure adjustment duty ratio to decrease the hydraulic pressure.

However, when the minimum turbine speed change rate dNt _min in the first predetermined section is greater than or equal to the first predetermined change rate, it is determined that the interlock phenomenon does not occur and the duty rate is determined according to the vehicle speed state of the traveling vehicle. Calibrate

In the case where the interlock phenomenon does not occur in the above, the shift controller 30 measures the current driving vehicle speed N _o according to the signal output from the vehicle speed detection unit 20, and then the current driving vehicle speed N _o . Comparing the set vehicle speed for determining whether or not the high speed (S140).

The set vehicle speed according to the embodiment of the present invention is about 2000 rpm.

When the current traveling vehicle speed is 2000 rpm or more, it is determined that the vehicle is in the high speed driving state, and the second set value for determining whether the run-up and the tie-up occurs is set to a value corresponding to the high speed driving (S150). If it is slower than 2000 rpm, the second set value is set to a value corresponding to low speed driving (S160).

According to the embodiment of the present invention, the second set value at high speed is about 1.9, and the second set value at low speed is about 2.2.

After setting the second set value for determining whether run-up and tie-up occur according to the vehicle speed of the traveling vehicle as described above, the shift control unit 30 determines the turbine rotation speed average change rate dN _ave of the second section. In operation S170, a comparison is made between a value calculated by multiplying the second set value set above by the second set change rate, that is, the target turbine speed change rate Ni2 in the second section.

Target turbine rotation of the second predetermined section when the second set value according to an embodiment of the present invention is a variable for limiting the average rate of change of the turbine speed change allowed in the second predetermined section, when downshifting from the third speed to the second speed An arbitrary value is multiplied by the number change rate, and a plurality of simulated shift experiments are performed according to the value, and then the value multiplied just before the run-up phenomenon occurs is set as the second set value.

In the above case, when the average turbine speed change rate dN _ave of the second section is smaller than the second set change rate, it is determined that a run up that rapidly increases the turbine speed does not occur, and whether or not a tie up occurs is determined accordingly. Set the correction amount.

In order to determine whether a tie-up has occurred in a state in which the current vehicle state does not generate a run-up, the shift control unit 30 determines the turbine rotation speed average change rate dNt _ave and the third set change rate, that is, the second set change rate in the second setting section. The value calculated by multiplying the target turbine speed change rate Ni2 in the set section by the third set value is compared and determined (S180).

The third set value according to the embodiment of the present invention is a variable for limiting the minimum change rate of turbine speed allowable in the second set section, and the target turbine rotation of the second set section when downshifting from three speeds to two speeds. An arbitrary value is multiplied by the number change rate, and a plurality of simulated shift experiments are performed according to the value, and then the value multiplied just before the tie-up phenomenon occurs is set as the third set value. According to an embodiment of the present invention, the third set value is about 1.0.

When the average turbine speed change rate dNt _ave in the second set section is less than the third set change rate, an interlock phenomenon or a tie-up phenomenon in which the clutch is fastened due to a high hydraulic pressure applied to the clutch in the current vehicle state may occur. It is determined that the generated state, in order to reduce the hydraulic pressure applied to the clutch is set by increasing the duty amount (b) by a predetermined value (S190).

However, when the turbine speed average change rate dNt _ave in the second set section is greater than or equal to the third set change rate, it is determined that a normal shift operation is being performed and the duty cycle correction amount is set to '0' ( S200).

In the above case, when the turbine speed average change rate dN _ave of the second section is larger than the second set change rate, it is determined that a runup in which the turbine speed is rapidly increased may occur, and whether the time when the clutch is engaged is reached. Perform duty ratio correction accordingly.

In other words, in the case where the average value dN _ave of the turbine speed change rate in the second section is larger than the second set change rate, the control is performed until the synchronous point at which the vehicle speed, which is the output speed of the transmission, and the turbine speed are equal to each other have passed. The time point at which the clutch is engaged without a gap is estimated according to the duty ratio (S210).

In the above, when the current vehicle state reaches the time when the clutch is engaged at the synchronous point, the shift controller 30 compares the relationship between the vehicle speed, which is the output speed of the transmission, and the turbine speed, which is the speed of the transmission input, again, to possibly cause a runup. To judge.

If the turbine rotation speed currently measured is equal to or greater than the preset rotational speed, that is, the second gear ratio multiplied by the vehicle speed and the fourth set value, it is again determined whether the turbine rotational speed is maintained for a predetermined time (about 60 msec). Determine (S220).

The fourth set value is a variable for limiting the output speed of the transmission for determining whether a run-up has occurred, and multiplies the current vehicle speed with an arbitrary value by multiplying the output speed of the transmission by the current vehicle speed when the speed is downshifted from 3 speeds to 2 speeds. Then, after performing a plurality of simulated shift experiments, the value multiplied just before the run-up phenomenon is set to the fourth set value. According to an embodiment of the present invention, the fourth set value is about 30 rpm.

In the case where the value of the turbine rotation speed is higher than the set rotation speed for a predetermined time, run-up in which the turbine rotation speed, which is the input torque, increases and decreases beyond the rotation speed corresponding to 2 speed due to the lack of hydraulic pressure acting as a friction element. It is determined that the phenomenon can occur, and the correction amount b is set to decrease by a constant value (-0.4%) so that the duty ratio is reduced to increase the oil pressure (S230 to S240).

However, when the turbine rotation speed is less than or equal to the set rotation speed, it is determined that the normal shift operation is being performed, and the duty cycle correction amount is set to '0' (S250).

On the contrary, in the above, when the current vehicle state does not reach the point where the clutch is engaged at the synchronous point, the shift control unit 30 is a tie-up or interlock in which the hydraulic pressure acting as a friction element is strong and the turbine speed is increased rapidly. It is determined that the phenomenon can occur, and the correction amount b is increased by a constant value (0.4%) so as to reduce the duty ratio to increase the oil pressure (S130).

As described above, the shift control 30 sets the initial duty ratio correction amount according to the change rate of the turbine rotation speed according to the shift operation of the vehicle and the vehicle speed, and then calculates the initial duty ratio according to the vehicle speed output from the transmission according to the shift operation.

In other words, when the vehicle speed is greater than the set vehicle speed, the shift control unit 30 determines that the current vehicle speed is high speed, and the correction amount set according to the turbine rotation speed change rate and the vehicle speed in the set basic duty ratio at high speed ( By adding b) to calculate the initial duty rate for performing the feedback control (S260 ~ S270).

On the contrary, when the detected vehicle speed is a low speed state which is equal to or smaller than the set vehicle speed, the initial duty ratio for feedback control is calculated by adding the correction rate set according to the turbine speed change rate and the vehicle speed to the set basic duty rate at low speed. (S280).

The basic duty ratio according to the vehicle speed state is calculated according to an experimental value and stored in a memory (not shown).

After calculating the initial duty ratio for the feedback control according to the turbine speed change rate and the vehicle speed according to the downshift operation from the third speed to the second speed as described above, the shift control unit 30 according to the calculated initial duty ratio 40 By controlling the oil pressure by driving the control, it is controlled so that the input torque variation of the transmission is ideally made (S290 to S300).

In the embodiment of the present invention, the shift feedback control duty ratio is corrected when the vehicle shifts at the third speed and downshifts at the second speed. However, the shift feedback control duty ratio is not necessarily limited to the downshift from the third speed to the second speed. It is possible to apply.

As described above, according to the embodiment of the present invention, the duty ratio of the hydraulic valve is corrected in accordance with the relationship between the vehicle speed of the traveling vehicle and the turbine rotational speed and the transmission rotational speed of the transmission during downshifting of the automatic transmission vehicle. According to the more appropriate feedback control can be made to improve the shift quality of the transmission.

In addition, it is possible to provide a feedback control initial duty ratio correction device and method for shifting a vehicle having an effect of performing a smooth shift operation according to a vehicle driving state.

Claims (26)

Turbine rotational speed sensing means for sensing the turbine rotational speed, which is an input rotational speed of the transmission, and outputting an electrical signal corresponding thereto; Vehicle speed detecting means for detecting a vehicle speed which is an output speed of the transmission and outputting an electrical signal corresponding thereto; In the case of downshifting, after dividing the sections into a plurality of sections according to the arrival rate to the target turbine rotational speed, the rate of change of the turbine rotational speed at the time of downshifting in the first predetermined section is measured so that the minimum turbine rotational speed change rate is set to the first setting. If the change rate is smaller than the change rate, it is determined that an interlock phenomenon may occur, and the duty rate is increased. If the change rate of the minimum turbine speed is equal to or greater than the first set change amount, the current speed is faster than the set speed. Set the second set value corresponding to the high speed, and if the vehicle speed is slower than the set vehicle speed, set the second set value corresponding to the low speed, and then the average rate of change of the turbine speed in the second set section is If the change rate is less than or equal to the set change rate, the turbine rotation speed average change rate and the third set change rate in the second section are compared and judged. If the duty ratio correction is performed according to the above, and the average turbine rotation rate change rate is larger than the second predetermined change rate in the second section, the duty ratio correction is performed according to whether or not the turbine rotation speed has reached the point where the clutch is engaged at the same synchronous point as the vehicle speed. Initial duty ratio correction device for the feedback control during the vehicle shift, characterized in that it comprises a shift control means for performing. The initial duty ratio correcting apparatus for feedback control during vehicle shifting according to claim 1, wherein the shift control means sets the first set change rate as follows. First set rate of change = target turbine speed change rate in first set section x first set value First set value = variable for defining the minimum allowable turbine speed change rate in first set section. The initial duty ratio correcting apparatus of a feedback control during vehicle shifting according to claim 2, wherein the shift control means sets the first set value to 0.7. 2. The initial duty ratio correcting apparatus for feedback during vehicle shifting according to claim 1, wherein the shift control means sets the second set change rate as follows. 2nd set change rate = target turbine speed change rate in a 2nd setting section x 2nd set value 2nd set value = a parameter for limiting the allowable average turbine speed change rate in a 2nd setting section. The initial speed ratio correction of the vehicle shift control according to claim 4, wherein the shift control means sets the second set value at high speed to 1.9 and the second set value at low speed to 2.2. Device. The turbine speed average change rate according to claim 1, wherein the shift control means compares the turbine speed average change rate in the second section with a third set change rate for determining whether a tie-up has occurred. If it is less than or equal to the rate of change, it is determined that a tie-up can occur, and the correction amount is increased to increase the duty rate, and when the turbine rotation rate average rate of change is greater than the third set rate of change, the feedback control at the time of shifting the vehicle is determined. Initial Duty Ratio Corrector. The initial duty ratio correcting apparatus of feedback control during vehicle shifting according to claim 6, wherein the shift control means sets the third set change rate to a value calculated as follows. 3rd set change rate = target turbine speed change rate in a 2nd section x 3rd set value 3rd set value = a parameter for limiting the minimum allowable turbine speed change rate in a 2nd set section. 8. The apparatus of claim 7, wherein the shift control means sets the third set value to 1.0. 2. The speed change control means according to claim 1, wherein the shift control means compares the turbine rotational speed with the set rotational speed when the current vehicle state reaches the time when the clutch is engaged at the synchronous point, and the turbine rotational speed is set. If it is larger, it is determined that it is a run-up state, and the correction amount is decreased by a certain value so that the hydraulic pressure is increased. When the current vehicle state does not reach the time when the clutch is engaged at the synchronous point, the correction amount is increased by a constant value so that the hydraulic pressure is increased. An initial duty ratio corrector for feedback control during vehicle shifting. 10. The initial duty ratio correction apparatus of claim 9, wherein the shift control means sets the set rotation speed to a value calculated as follows. Set Speed = Downshift Shift Gear Ratio × Vehicle Speed × Fourth Set Value Fourth Set Value = Variable for limiting the output speed of the transmission to determine whether run-up has occurred. 10. The method of claim 9, wherein the shift control means, if the turbine rotational speed is greater than the set rotation speed, it is determined whether the turbine rotational speed maintains a state having a value greater than the set rotational speed for a predetermined time, the turbine rotational speed is set rotation It is determined that the current vehicle state is in the run-up state only when the value larger than the number is maintained for a predetermined time, and the normal state is determined when the turbine speed is not maintained for a predetermined time. Initial duty ratio correction device for feedback control during vehicle shifting. 2. The speed change control means according to claim 1, wherein the shift control means sets a correction amount according to the turbine speed change rate, and then, when the detected vehicle speed is higher than the set vehicle speed, the speed change rate of the turbine speed is changed from the basic duty rate at high speed. The initial duty ratio for feedback control is calculated by adding the correction amount set accordingly, and when the detected vehicle speed is slower than the set vehicle speed, feedback control is performed by adding the correction amount set according to the turbine rotation rate change from the basic duty rate at low speed. Initial duty ratio correction apparatus for feedback control during vehicle shift, characterized in that for calculating the early duty ratio for. 2. The initial duty ratio correcting apparatus of claim 1, wherein the shift control means performs an initial duty ratio correction operation when the vehicle shifts at three speeds and is downshifted at two speeds. Dividing the sections into a plurality of sections according to an increase in turbine rotation speed, that is, an arrival rate for the target turbine rotation speed; Measuring down rate by sampling the turbine rotational speed output from the turbine rotational speed sensing means every predetermined time when the downshift is performed; The first change rate of the turbine rotational speed during downshifting is measured, and the minimum turbine rotational speed change rate in the first predetermined section and the hydraulic pressure applied during the downshifting are too high to cause an interlock phenomenon in which the clutch is fastened. Comparing and determining a set change rate; When the minimum turbine speed change rate is smaller than the first set change rate, determining that the currently operated hydraulic pressure is too high so that an interlock phenomenon may occur, and setting the correction amount by increasing a fixed value; Setting a duty rate correction amount for increasing or decreasing the hydraulic pressure according to the measured turbine speed change rate and the vehicle speed, and comparing the current running vehicle speed with the set vehicle speed when the minimum turbine speed change rate is equal to or greater than the first predetermined change amount. And setting a second set value corresponding to the high speed when the vehicle speed is faster than the set vehicle speed, and setting a second set value corresponding to the low speed when the vehicle speed is slower than the set vehicle speed; Comparing and determining the turbine rotation speed average change rate in the second section and the second set change rate for determining whether the run-up occurs, and again if the turbine rotation rate average change rate in the second section is less than or equal to the second set change rate. Comparing and determining the turbine engine speed average change rate in the two sections with a third set change rate for determining whether a tie-up has occurred and performing duty rate correction accordingly; If the turbine speed average change rate in the second section is greater than the second set change rate, performing a duty rate correction according to whether or not the turbine speed reaches a time when the clutch is engaged at the same synchronous point as the vehicle speed; Calculating the initial duty ratio for feedback control by adding the correction amount set according to the turbine rotation speed change rate from the basic duty ratio at high speed when the detected vehicle speed is faster than the set vehicle speed; When the detected vehicle speed is slower than the set vehicle speed, the vehicle comprises the step of calculating the initial duty ratio for feedback control by adding the correction amount set according to the turbine rotation rate change rate from the basic duty ratio at the low speed. Initial duty ratio correction method of feedback control in shifting. 15. The method of claim 14, wherein the first set change rate is set as follows. First set rate of change = target turbine speed change rate in first set section x first set value First set value = variable for defining the minimum allowable turbine speed change rate in first set section. 16. The method of claim 15, wherein the first set value is set to 0.7. 15. The method of claim 14, wherein the second set change rate is set as follows. 2nd set change rate = target turbine speed change rate in a 2nd setting section x 2nd set value 2nd set value = a parameter for limiting the allowable average turbine speed change rate in a 2nd setting section. 18. The method of claim 17, wherein the second set value at high speed is set to 1.9 and the second set value at low speed is set to 2.2. 15. The method of claim 14, wherein the turbine speed average change rate in the second section is compared with the third set change rate for determining whether a tie-up has occurred, and when the turbine speed average change rate is less than or equal to the third set change rate. Determining that a tie-up can occur, and increasing the correction amount so that the duty ratio is increased; And determining the steady state when the turbine rotation speed average change rate is larger than the third set change rate. 20. The method of claim 19, wherein the third set change rate is set to a value calculated as follows. 3rd set change rate = target turbine speed change rate of a 2nd oral department x 3rd set value 3rd set value = a variable for limiting the minimum allowable turbine speed change rate in a 2nd set section. 21. The method of claim 20, wherein the third set value is set to 1.0. 15. The turbine rotation speed according to claim 14, wherein in the step of correcting the duty ratio according to whether or not the timing at which the clutch is engaged at the synchronous point is reached, when the current vehicle state reaches the timing at which the clutch is engaged at the synchronous point, Comparing and determining the set rotation speed; Determining that the turbine rotational speed is greater than the set rotational speed to reduce the correction amount by a predetermined value to increase the hydraulic pressure; And if the current vehicle state does not reach the point at which the clutch is engaged at the synchronous point, increasing the correction amount by a predetermined value such that the oil pressure is increased. 23. The method of claim 22, wherein the set rotation speed is set to a value calculated as follows. Set Speed = Downshift Shift Gear Ratio × Vehicle Speed × Fourth Set Value Fourth Set Value = Variable to limit the number of revolutions on the output side of the transmission to determine whether run-up has occurred. 23. The method of claim 22, wherein the comparing of the turbine speed and the set speed comprises: determining whether the turbine speed is greater than the set speed for a predetermined time when the turbine speed is greater than the set speed. Wow; If the turbine speed is greater than the set speed for a predetermined time is determined as a run-up state, and if the turbine speed is greater than the set speed for a predetermined time it is determined that the normal state The initial duty ratio correction method of the feedback control during vehicle shift further comprising. 15. The method of claim 14, wherein the correction amount is set according to the turbine speed change rate, and at a high speed at which the detected vehicle speed is faster than the set vehicle speed, the correction amount set according to the turbine speed change rate is added to the feedback at the basic duty rate at high speed. Calculating an initial duty rate for control; When the detected vehicle speed is slower than the set vehicle speed, the vehicle shift feedback further comprises calculating an initial duty ratio for feedback control by adding a correction amount set according to the turbine rotation speed change rate from the basic duty ratio at low speed. Initial duty ratio correction method of control. 15. The method of claim 14, wherein the initial duty ratio correction operation is performed when the vehicle travels at the third speed and downshifts at the second speed.