JP2003042284A - Hydraulic controller for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic controller for an automatic transmission capable of achieving a favorable shift feeling by ideally changing a slip amount in clutch-to-clutch shift control of an automatic transmission. SOLUTION: The hydraulic controller for the automatic transmission is provided with a reference model M(s) where an output becomes a slip amount gradually and ideally changing with passage of time when it is provided with a stepwise changing target slip amount, and the output Mout of the reference model M(s) is set as a target slip amount of a feedback controller Cpi(s). An error err between the reference model M(s) and an actual slip amount sp is determined by subtracting the slip amount sp from the output Mout of the reference model M(s). The error err is used as an input of a predetermined controller Cef (a controller multiplying an input amount by a gain T and outputting it), and an output of the controller Cef is superimposed on an input of the controller Cpi(s).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for an automatic transmission for a vehicle, which controls a plurality of friction engagement elements to automatically switch gears, and more particularly to engagement and engagement of friction engagement elements. The present invention relates to a hydraulic control device for an automatic transmission that appropriately controls the hydraulic pressure for releasing.

[0002]

2. Description of the Related Art In gear shifting of an automatic transmission, it is necessary to reduce the transmission torque carried by the disengagement side frictional engagement element as the transmission torque of the engagement side frictional engagement element increases. The one-way clutch is a mechanism adopted to reduce the transmission torque carried by the disengagement side frictional engagement element.
On the other hand, in recent years, the "Clutch to Clutch" shift control has been adopted in which the one-way clutch is abolished and the function of the one-way clutch is achieved by hydraulically controlling the friction engagement elements. There is.

In such clutch-to-clutch shift control, unless the hydraulic control is properly performed, the output torque of the automatic transmission suddenly changes and the shift feeling is deteriorated. For example, if the reduction of the transmission torque of the disengagement side friction engagement element is delayed with respect to the increase of the transmission torque of the engagement side friction engagement element, a so-called interlock state occurs and the output torque sharply decreases. On the other hand, if the transmission torque of the disengagement side friction engagement element decreases too fast with respect to the transmission torque of the engagement side friction engagement element, the turbine rotation speed increases (the turbine rotation speed rises), and therefore the output torque increases. Torque decreases sharply.

In order to deal with this, so-called slip amount control is considered in which the transmission torque of the disengagement side frictional engagement element is reduced to cause a slip, and in that state, the transmission torque of the engagement side frictional engagement element waits for an increase. Has been done. As an example of this control, as shown in FIG. 11, it is conceivable that the slip amount is feedback-controlled by the feedback controller Cpi (s). In this case, the target slip amount is
It is a value that changes stepwise from “0” to a predetermined value rs, and is a controller Cpi (s) for feedback control.
Is composed of a general PI controller (proportional integral controller). Also, P (s) is the control target (automatic transmission body)
Of the hydraulic pressure of the release side, and the output is the actual slip amount (actual slip amount), and is determined using the system identification method.

[0005]

However, if the slip amount is controlled by such a system, it is difficult to control the slip amount to a desired value during the period until the slip amount converges by the feedback control. As a result,
For example, since the slip amount sharply increases as shown at times t10 to t20 in FIG. 12B or the slip amount fluctuates up and down as shown at times t20 to t30, the broken line circle in FIG. As shown in the figure, there is a problem that the output torque fluctuates greatly and shift shock occurs. Therefore,
An object of the present invention is to provide an automatic transmission that can ideally change the slip amount in the clutch-to-clutch shift control of the automatic transmission smoothly and without causing a shift shock to achieve a good shift feeling. To provide a hydraulic control device.

[0006]

SUMMARY OF THE INVENTION A feature of the present invention is that a predetermined shift speed is achieved by controlling hydraulic pressure applied to each of a plurality of friction engagement elements to maintain the friction engagement elements in an engaged state or a released state. However, when shifting from one shift stage to another shift stage, the hydraulic pressure applied to the disengagement side friction engagement element that is in the engaged state before the same shift and is in the released state after the same shift is reduced to reduce the disengagement side friction. Slip is generated by reducing the transmission torque by the engagement element, and the hydraulic pressure applied to the engagement side friction engagement element that is in the released state before the same gear shift and is in the engaged state after the same gear shift is increased. An oil pressure control device for an automatic transmission that performs the same gear shift by increasing a transmission torque by an engagement side frictional engagement element, wherein a deviation between an actual slip amount representing the magnitude of the actually generated slip and a target slip amount. Is the input amount, and A feedback controller that feedback-controls the hydraulic pressure applied to the disengagement side frictional engagement element so that the slip amount matches the target slip amount, and an ideal feedback controller that continuously and gradually changes over time and does not cause a shift shock. And a target slip amount generating means for generating a slip amount as the target slip amount.

In this case, it is preferable that the feedback controller is a PI controller based on proportional-plus-integral control, and the target slip amount generating means receives an input that changes stepwise from 0 to a predetermined value. In addition, it is preferable that it is configured by a reference model that outputs the target slip amount.

According to this, since the target slip amount continuously changes gradually, the actual slip amount by feedback control can be made to follow the target slip amount, and the target slip amount causes a shift shock. Since it is the ideal amount of slip that will not be caused, the clutch of the automatic transmission
It is possible to improve the feeling of gear shifting during two-clutch gear shifting.

Further, in this case, an error feedback controller which inputs the difference between the actual slip amount and the output of the reference model is added, and the output of the error feedback controller is superimposed on the input of the feedback controller. It is preferable to configure.

As a result, even if the characteristics of the controlled object fluctuate due to manufacturing errors, this fluctuation can be automatically absorbed, so that the labor required for adaptation can be reduced and the manufacturing cost can be reduced. .

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a hydraulic control device for an automatic transmission for a vehicle according to the present invention will be described below with reference to the drawings. FIG. 1 schematically shows an example in which the hydraulic control device for the automatic transmission is mounted on a vehicle. This vehicle includes an engine 10 as a prime mover, a hydraulic torque converter 20 with a lockup clutch, and an automatic transmission 30.
And a hydraulic control circuit 4 for controlling the pressure (hydraulic pressure) of the oil supplied to the torque converter 20 and the automatic transmission 30.
0 and an electric control device 50 that gives a control instruction signal to the hydraulic control circuit 40, and the torque generated by the engine 10 that is increased or decreased by operating an accelerator pedal (not shown)
Torque converter with lockup 20, automatic transmission 3
0, and is transmitted to the drive wheels via a differential gear device (differential gear) not shown.

The torque converter with lockup 20 is
As shown in FIG. 1 and FIG. 2, a fluid type transmission mechanism 21 that transmits the power generated by the engine 10 to the automatic transmission 30 via a fluid (hydraulic oil), and a fluid transmission mechanism 21 that is parallel to the fluid transmission mechanism 21. And a lockup clutch mechanism 22 connected to the.

The hydraulic transmission mechanism 21 is a torque converter input shaft 1 that rotates integrally with the crankshaft of the engine 10.
2, a pump impeller 21a, a turbine impeller 21b that is rotated by the flow of hydraulic oil generated by the pump impeller 21a, and is connected to the input shaft 31 of the automatic transmission 30, and a stator impeller 21c. (Omitted in FIG. 1).

As shown in FIG. 2, the lockup clutch mechanism 22 is configured to include a lockup clutch 22a, and the hydraulic converter circuit 40 connected to the lockup clutch mechanism 22 supplies and discharges the hydraulic oil to the torque converter input shaft 12. And the input shaft 31 of the automatic transmission 30 with the lockup clutch 22.
It is possible to achieve an engaged state in which they are mechanically coupled by a to rotate them integrally and a non-engaged state in which the mechanical coupling by the lock-up clutch 22a is released.

As shown in FIG. 2, the automatic transmission 30 achieves 6 forward speeds and 1 reverse speed. As shown in FIG. 2, a first row single pinion planetary gear G1 having a ring gear R1 and a second gear. A single pinion planetary gear G2 in a row and a single pinion planetary gear G3 in a third row are provided, and friction clutches C1, C2, C3 and friction brakes B1, B2 are provided as friction engagement elements. The relationship between the engaged / released state of each frictional engagement element in the automatic transmission 30 and the achieved shift speed is as shown in Table 1 below. In Table 1, ◯ indicates the engaged state, and blank indicates the released state.

[0016]

[Table 1]

As shown in FIG. 1, the hydraulic control circuit 40 includes three on / off solenoid valves 41 to 43 and 4 controlled by a control finger signal from an electric control unit 50.
Including linear solenoid valves 44-47,
The supply / discharge of oil to / from the friction engagement element of the automatic transmission 30 is controlled based on the combination of the operations of the on / off solenoid valves 41 to 43, and the linear solenoid valves 44 to 46 are driven to supply / discharge the same. The oil pressure (hydraulic pressure) can be adjusted within the range of line pressure or less. Further, the hydraulic pressure supplied to and discharged from the lock-up clutch mechanism 22 by driving the linear solenoid valve 47 can be adjusted within a range below the line pressure.

The electric control unit 50 is a microcomputer including a CPU, a memory (ROM, RAM), an interface, etc., all of which are omitted from the drawing, and includes a throttle opening sensor 61, an engine speed sensor 62,
It is connected to the turbine rotation speed sensor 63 and the output shaft rotation speed sensor 64, and inputs signals generated by these sensors 61 to 64.

The throttle opening sensor 61 is used for the engine 1
The opening of the throttle valve 11 provided in the intake passage of 0 and opened / closed in response to the operation of an accelerator pedal (not shown) is detected, and a signal representing the throttle opening th is generated. The engine rotation speed sensor 62 detects the rotation speed of the engine 10 and generates a signal representing the engine rotation speed ne. The turbine rotation speed sensor 63 detects the rotation speed of the input shaft 31 of the automatic transmission and generates a signal representing the turbine rotation speed nt. The output shaft rotation speed sensor 64 detects the rotation speed (output rotation speed) of the output shaft 32 of the automatic transmission and generates a signal representing the output shaft rotation speed (that is, a value proportional to the vehicle speed) no. It has become.

The electric control device 50 stores in the memory a shift map and a lockup clutch operation map which are composed of the output shaft rotational speed no and the throttle opening th, and the detected output shaft rotational speed no. When the point determined by the detected throttle opening th crosses the shift line shown in the shift map, the on / off solenoid valves 41 to 43 and the linear solenoid valves 44 to 46 of the hydraulic control circuit 40 are controlled to As shown in Table 1, the engagement / release state of the friction engagement element is changed. At the same time,
The linear solenoid valve 47 is controlled according to whether or not the point is within the lockup region of the lockup clutch operation map to engage / disengage the lockup clutch 22a.
It is designed to change the release status.

Next, the clutch-to-clutch control performed by the hydraulic control device for an automatic transmission configured as described above at the time of shifting from the second speed to the third speed will be described.

(Outline) First, an outline of hydraulic control at the time of shifting from the second speed to the third speed will be described with reference to FIGS. 3 (A) to 3 (E). In addition, in FIG. 3 (A), a solid line and a broken line indicate a release side frictional engagement element (brake B).
The command hydraulic pressure for 1) (hereinafter, referred to as "disengagement command hydraulic pressure") and the command hydraulic pressure for the engagement side frictional engagement element (clutch C3) (hereinafter, referred to as "engagement command hydraulic pressure"), respectively. It represents. Further, in FIG. 3B, the solid line and the broken line represent the actual hydraulic pressure for the disengagement side frictional engagement element (hereinafter referred to as “disengagement side hydraulic pressure”) and the actual hydraulic pressure for the engagement side frictional engagement element. (Hereinafter, referred to as "engagement side hydraulic pressure").

At time t1, when the point defined by the output shaft rotational speed no and the throttle opening th crosses the shift-up shift line from the 2nd speed to the 3rd speed, the electric control unit 50 changes the release side hydraulic pressure from the line pressure PL. Perform initial ramp release control that reduces rapidly. As a result, the disengagement side frictional engagement element begins to slip at time t3. Next, the electric control device 5
0 performs slip amount feedback control which will be described later. As a result, as shown in FIG. 3 (E), the slip amount smoothly rises from time t3 to t4.

On the other hand, the electric control unit 50 performs precharge control for rapidly increasing the engagement-side hydraulic pressure for a predetermined time from time t1, and when the precharge control ends at time t2, the engagement-side oil pressure continues until slip starts. Engagement standby pressure control that maintains the hydraulic pressure at a constant value is performed. Then, when the slip starts at time t3, the shelf pressure control for maintaining the engagement side hydraulic pressure at a predetermined pressure is started. As a result, the engagement-side frictional engagement element starts transmitting torque and the slip amount begins to decrease. At this time, the electric control device 50 tries to maintain the slip amount at the target value by the slip amount feedback control, so that the release side hydraulic pressure is reduced in order to increase the slip amount.

When this state continues and the slip amount disappears at time t5, the electric control unit 50 immediately reduces the hydraulic pressure on the disengagement side to "0", and at the same time, the target rate of change Δnt of the hydraulic pressure nt on the engaging side is set to the target. The inertia feedback control for controlling the rotation change rate ΔMNT is executed. Then, at time t6, the turbine rotation speed nt is changed after the gear shift (third speed in this case) and the output shaft rotation speed n.
When it matches the product with о, the hydraulic pressure on the engagement side is increased to the line pressure PL. As described above, the clutch-to-clutch shift is completed.

(Principle of Slip Amount Feedback Control)
Next, the principle of the slip amount feedback control at the above-mentioned times t3 to t5 will be described. First, consider the reference model M (s) shown in FIG. This reference model M
As shown in FIG. 5, when the target slip amount rslip, which changes stepwise from 0 to a predetermined value rs, is given as an input, (s) gradually changes with time and the value tr Target slip amount rsli after a time determined by
It outputs an ideal slip amount Mout "not causing a shift shock" that reaches p (the predetermined value rs), and the transfer function of the reference model M (s) is a "binomial model".
Is determined using. Specifically, the reference model M (s)
Is represented by the following formula 1. In Expression 1, “s” is a differential operator.

[0027]

## EQU1 ## M (s) = 1 / (tr.s + 1) ²

Then, as shown in FIG.
A closed loop system is constructed in which (s) is feedback-controlled using a feedback controller Cpi (s) which is a proportional-integral controller (PI controller), and the target input value of the feedback controller Cpi (s) is set to the reference model M (s). ) Output Mout. Therefore, the reference model M
(S) constitutes a target slip amount generation means.

In this case, the controlled object P (s) has the input as the release hydraulic pressure (engagement pressure of the brake B1) and the output as the actual slip amount (actual slip amount) sp.
It is the transfer function of the entire automatic transmission determined using the system identification method.

Feedback controller Cpi (s)
Is expressed by the following equation 2, and constitutes the normal feedback system shown in FIG. 11 after determining the controlled object P (s), and the target slip amount that changes stepwise from 0 as the target value to the predetermined value rs. And a proportional gain (proportional sensitivity) Kp and an integral gain (integral sensitivity) Ki that enable feedback control (servo) without vibrating and diverging the actually generated slip amount are obtained by experiments. The actual disengagement side command hydraulic pressure is determined based on the output of the feedback controller Cpi (s).

[0031]

(2) Cpi (s) = Kp + Ki / s

Further, in the present embodiment, as shown in FIG. 6, by subtracting the actual slip amount sp which is the output of the feedback control system from the output Mout of the reference model M (s), the reference model M The error err between (s) and the actual slip amount sp is calculated, and the error err is used as an input of a predetermined controller Cef (in the example of FIG. 6, a controller that multiplies the input amount by the gain T and outputs). The system is configured to superimpose the output on the input of the feedback controller Cpi (s). The controller Cef (gain T in the example of FIG. 6) is set so as to actually control the slip amount of the automatic transmission based on the system shown in FIG. 6 and prevent the actual slip amount from diverging at that time. .

By controlling the hydraulic pressure on the release side in this way, the change in the target slip amount is relatively smooth even if there is a response delay (control delay) in the feedback control system due to the feedback controller Cpi (s). , The actual slip amount sp can be changed by following the output of the reference model M (s), and as a result, fluctuations in the output torque of the automatic transmission 30 can be suppressed. More than,
This is the control principle of slip amount feedback.

(Specific Operation) Next, a specific operation of the hydraulic control device for the automatic transmission at the time of shifting from the second speed to the third speed will be described. The CPU of the electric control device 50 is
The release side hydraulic pressure control routine shown by the flowchart in FIG. 7 is repeatedly executed every time a predetermined time elapses. Therefore, when the predetermined timing comes, the CPU proceeds to step 70.
The processing is started from 0, and the routine proceeds to step 705, where it is determined whether or not the shift-up timing from the 2nd speed to the 3rd speed is determined by the output shaft rotation speed no and the throttle opening th. The determination is made based on whether or not the shift up line to the high speed is crossed. At this time, from 2nd to 3rd
If it is not the fast shift-up timing, the CPU makes a “No” determination at step 705 to proceed to step 795 to end the present routine tentatively.

On the other hand, if the shift-up timing of the second speed to the third speed is currently reached, the CPU makes a "Yes" determination at step 705 to determine steps 710 to 745.
Then, the initial lamp release control is started. Specifically, in step 710, the CPU sets the release side instruction hydraulic pressure PD to a value obtained by subtracting the predetermined pressure SK from the line pressure PL. As a result, the linear solenoid valve 44 is driven and the disengagement hydraulic pressure is reduced by the predetermined pressure SK (see time t1 in FIG. 3).

Next, the CPU proceeds to step 715 to reset and start the timer T1 (start time counting), and at step 720, the value of the timer T1 is set to the predetermined value T.
It is repeatedly determined whether or not it is larger than A. As a result, the release side command hydraulic pressure PD is maintained at a constant value while the value of the timer T1 is smaller than the predetermined value TA. Then timer T
When the value of 1 becomes larger than the predetermined value TA, the CPU makes a “Yes” determination at step 720 to proceed to step 725, at which the timer T1 is reset and started again, and at the following step 730. Actual slip amount
Monitor whether sp is greater than "0" (that is, whether slip has started). Here, the actual slip amount sp is calculated by the following expression 3. In Expression 3, the value G1 is the gear ratio before gear shifting (here, the gear ratio of the second speed).

[0037]

[Equation 3] sp = nt-nо ・ G1

If slip occurs at this stage, C
The PU makes a “Yes” determination at step 730 to proceed to step 750 to execute slip amount feedback control. If no slip has occurred at this stage, the CPU makes a “No” determination at step 730 to proceed to step 735 to determine whether the value of the timer T1 is greater than a predetermined value TA. At this point in time, the timer T1 is just after starting the time measurement in the previous step 725, so the value of the timer T1 is smaller than the predetermined value TA. Therefore, CP
U determines “No” in step 735 and determines in step 7
In step 740, the value of the disengagement side instruction hydraulic pressure PD is decreased by a predetermined value α, and in step 745, the process waits for a short time Δt from the execution of the previous step 740 and then proceeds to step 730. Return. In this way, C
The PU reduces the release side command hydraulic pressure PD by a predetermined value α every time Δt, and monitors the start of slip in step 730. Therefore, if a slip occurs before the value of the timer T1 becomes larger than the predetermined value TA, the CPU makes a “Yes” determination at step 730 to proceed to step 750 to start the slip amount feedback control (FIG. 3).
See time t3). On the other hand, the value of the timer T1 is the predetermined value TA
If no slip occurs before it becomes larger, CPU
Is determined to be “Yes” in step 735 and is determined in step 7
Proceed to 55.

When the CPU proceeds to step 750, it starts the process of the slip amount feedback control routine shown in FIG. 8 from step 800 and proceeds to step 805 to discretize (Z-transform) the reference model M (z). The coefficients {am1, am2, bm0, bm1, bm2} of are read. Next, the CPU reads the proportional gain Kp and the integral gain Ki of the feedback controller Cpi in step 810, the error feedback gain T in step 815, and the value of the release hydraulic pressure P at that time in step 820. It is stored as the feedback initial value Pfb.

The CPU then proceeds to step 825 and
In step 825, the target slip amount rslip (n) is read, and in step 830, the output Mout (n) of the reference model M (z) is calculated according to the following equation 4. This target slip amount rslip is the amount that changes stepwise from "0" to the predetermined value rs, as shown in FIG. The subscript “n” indicates that the sampling is the n-th sampling.

[0041]

[Equation 4]

Next, the CPU proceeds to step 835, and in step 835, the output Mout of the reference model is output.
The actual slip amount sp is subtracted from (n) to obtain the model error amount err, and this is multiplied by T to obtain the error feedback amount
EFB (n) is obtained, and in the following step 840, the output Mout (n) of the reference model and the error feedback amount EFB
Input PIin (n) to the feedback controller Cpi by subtracting the actual slip amount sp from the sum of (n)
Ask for. Then, the CPU proceeds to step 845,
The output PIout (n) of the feedback controller Cpi is calculated according to the following equation 5. Note that Equation 5 is a discrete version of Equation 2 above, and SMPLT is the sampling time.

[0043]

[Equation 5]

Thereafter, the CPU outputs the output PIout of the feedback controller Cpi obtained in step 850.
A value obtained by adding the stored feedback initial value Pfb to (n) is set as the instruction pressure Psiji and output. As a result, the disengagement hydraulic pressure is controlled to Psiji. Then CP
U determines in step 855 whether or not the actual slip amount has disappeared, based on whether or not the actual slip amount sp has become “0”.

At this stage, immediately after the slip has started, the hydraulic pressure supplied to the engagement side frictional engagement element is small as will be described later, so the engagement side frictional engagement element has not started torque transmission. Therefore, since the actual slip amount sp is larger than “0”, the CPU makes a “No” determination at step 855 to return to step 825. After that, the CPU executes steps 825 to 85 until the actual slip amount sp becomes “0”.
Repeat 5

When the slip amount feedback control is performed in this manner, the actual slip amount sp substantially coincides with the output of the reference model M (s), as shown from time t3 to t4 in FIG. 3 (E). It will increase smoothly. As a result, the vertical variation of the output torque of the automatic transmission is small, and the shift feeling is good.

On the other hand, the CPU of the electric control unit 50 is shown in FIG.
The engagement-side hydraulic pressure control routine shown in the flowchart in FIG. 3 is repeatedly executed every time a predetermined time elapses. Therefore, at a predetermined timing, the CPU starts the process from step 900, proceeds to step 905, and proceeds to step 705.
Similarly, it is determined whether or not it is the shift-up timing from the second speed to the third speed. At this time, if it is not the shift-up timing of the second speed to the third speed, the CPU makes a “No” determination at step 905 to proceed to step 995 to end the present routine tentatively.

If the shift-up timing of the second speed to the third speed is currently reached, the CPU makes a "Yes" determination at step 905 to proceed to step 910, at which the engagement side is commanded to perform the precharge control. The hydraulic pressure PE is set to a predetermined precharge pressure PRCH (line pressure PL in this example). As a result, as shown at times t1 to t2 in FIG. 3B, the engagement side hydraulic pressure rises and the oil passage or the like is filled with oil. Next, the CPU resets and starts the timer T2 in step 915 (starts time counting), and then in step 92
At 0, it is determined whether the value of the timer T2 is larger than the predetermined value tprch. If the value of the timer T2 is smaller than the predetermined value tprch, step 920 is repeatedly executed.

After that, when the value of the timer T2 becomes larger than the predetermined value tprch, the CPU proceeds to step 925 to set the engagement side instruction hydraulic pressure PE to the predetermined standby pressure PTAIKI, and at the subsequent step 930, the actual slip amount sp becomes " It is monitored whether it has become larger than "0". On the other hand, as described above, when the predetermined time TA elapses from the shift-up timing from the 2nd speed to the 3rd speed, the hydraulic pressure on the release side starts to decrease, so that the slip occurs at the time t3 in FIG. Therefore, the CPU
Is determined as “Yes” in Step 930, and Step 9 is performed.
35, the engagement side command hydraulic pressure PE is set to a predetermined pressure (shelf pressure) PTANA larger than the standby pressure PTAIKI in the same step 935, and then, in step 940, it is determined whether the actual slip amount sp becomes 0 or not. To determine. As a result, the actual engagement-side hydraulic pressure rises, so that the engagement-side frictional engagement element starts torque transmission after a predetermined period of time, and the actual slip amount sp begins to decrease.

During this time, the release side hydraulic pressure is controlled by the slip amount feedback control by the feedback controller Cpi (s). This slip amount feedback control controls the disengagement hydraulic pressure so as to maintain the actual slip amount sp at the target slip amount. Therefore, when the slip amount begins to decrease as the engagement hydraulic pressure increases, the slip amount The release side hydraulic pressure (release side command hydraulic pressure PD) is decreased in an attempt to increase the amount.

Then, as shown at time t5 in FIG.
When the actual slip amount sp becomes "0", the CPU proceeds to step 9
Proceeding to 45, the engagement side hydraulic pressure is controlled so that the change rate Δnt of the turbine rotation speed nt becomes the target rotation change rate ΔMNT in order to end the torque phase and shift to the inertia phase. This is called inertia feedback control.

The CPU then proceeds to step 950 and
In the same step 950, it is determined whether or not the turbine rotation speed nt matches the product of the gear ratio G2 of the third speed after shifting and the output shaft rotation speed no, and if they do not match, the above step 9 is performed.
Return to 45. After that, when the turbine rotation speed nt matches the product of the gear ratio G2 of the third speed after the gear shift and the output shaft rotation speed no, the CPU makes a “Yes” determination at step 950 to proceed to step 955, at which step 955. The engagement side command hydraulic pressure PE is set to the line pressure PL at, and the engagement side hydraulic pressure control routine ends at step 995.

Further, as shown at time t5 in FIG. 3, when the actual slip amount sp becomes “0”, the CPU determines “Yes” in step 855 in FIG. 7, the release side command hydraulic pressure PD
Is set to "0", the routine proceeds to step 795, where the release side hydraulic pressure control routine is ended. As described above, the clutch-to-clutch shift control is executed.

In the release side hydraulic control of FIG. 7, if the slip does not occur before the value of the timer T1 becomes larger than the predetermined value TA, the CPU determines in step 735 “Yes”.
s ”is determined and the process directly proceeds to step 755. This is because slippage does not occur even though the release side hydraulic pressure is sufficiently reduced. Therefore, even if the release side hydraulic pressure is reduced at once without slipping, the turbine rotation speed n
This is because it is considered that the rising of t does not occur.

FIG. 10 is a time chart showing the actual measured value of the slip amount under such control. As is clear from FIG. 10, the actual slip amount sp changes following the target slip amount.

As described above, according to the above embodiment, the time change of the actual slip amount is the reference model M (s).
Controlled to follow the output of. As a result, even if the transmission torque by the engagement-side frictional engagement element rises later than the scheduled timing due to variations in the clutch stroke of the engagement-side frictional engagement element and changes in the hydraulic characteristics, slippage occurs. Since the quantity ideally rises and changes so as not to cause fluctuations in the output torque, a good shift feeling can be maintained. Further, in the above embodiment, since the model error amount err is obtained and fed back, even if the characteristic of the controlled object P (S) changes due to the manufacturing error, this change can be automatically absorbed. Therefore, the labor required for adaptation can be reduced and the manufacturing cost can be reduced.

The present invention is not limited to the above embodiment, and various modifications can be adopted within the scope of the present invention. For example, in the above embodiment, the shift from the second speed to the third speed has been described, but the present invention can be applied to the clutch-to-clutch control from another shift speed. In this case, the proportional gain (proportional sensitivity) Kp and the integral gain (integral sensitivity) Ki of the feedback controller Cpi (s), the gain T of the error feedback controller Cef, etc. are stored in the ROM in advance according to the type of shift. It is preferable to read the data according to the actual type of gear shift and use it for gear shift control.

[Brief description of drawings]

FIG. 1 is a schematic diagram when a hydraulic control device for an automatic transmission according to the present invention is installed in a vehicle.

FIG. 2 is a skeleton diagram of the automatic transmission shown in FIG.

3 (A) is a disengagement-side command hydraulic pressure and an engagement-side command hydraulic pressure at the time of shifting from the second speed to the third speed controlled by the hydraulic control device for the automatic transmission shown in FIG. ) Is the actual release side hydraulic pressure and engagement side hydraulic pressure, (C) is the engine speed and turbine speed, (D) is the output torque,
(E) is a time chart showing the actual slip amount.

FIG. 4 is a block diagram of a reference model used by the hydraulic control device for the automatic transmission shown in FIG.

5 is a time chart showing a target slip amount input to the reference model shown in FIG. 4 and an output of the reference model with respect to this input.

6 is a block diagram showing a connection relationship between a control target of the hydraulic control device for the automatic transmission shown in FIG. 1 and a controller used by the device.

7 is a flowchart of a program (routine) executed by the CPU of the electric control device shown in FIG.

8 is a flowchart of a program (routine) executed by the CPU of the electric control device shown in FIG.

9 is a flowchart of a program (routine) executed by the CPU of the electric control device shown in FIG.

FIG. 10 is a time chart showing an actual slip amount controlled by a hydraulic control device for an automatic transmission according to the present invention.

FIG. 11 is a block diagram showing a connection relationship between a control target of a hydraulic control device for a conventional automatic transmission and a controller used by the device.

FIG. 12 (A) is a time chart showing a turbine rotational speed at the time of shifting according to a conventional technique, (B) is a slip amount, and (C) is an output torque.

[Explanation of symbols]

10 ... Engine, 12 ... Torque converter input shaft, 20
... Fluid type torque converter with lock-up clutch, 2
DESCRIPTION OF SYMBOLS 1 ... Fluid type transmission mechanism, 22 ... Lock-up clutch mechanism, 30 ... Automatic transmission, 31 ... Input shaft, 32 ... Output shaft,
40 ... Hydraulic control circuit, 41-43 ... ON / OFF solenoid valve, 44-47 ... Linear solenoid valve, 50
... Electric control device, 63 ... Turbine rotation speed sensor, 64
... Output shaft rotation speed sensor, M (s) ... Reference model, P
(S) ... Control object, Cpi (s) ... Controller.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Sato Victory             Aichi, 2-chome, Asahi-cho, Kariya city, Aichi prefecture             Within Seiki Co., Ltd. (72) Inventor Yasuo Shirai             Aichi, 2-chome, Asahi-cho, Kariya city, Aichi prefecture             Within Seiki Co., Ltd. (72) Inventor Atsumi Ohara             19 Asahi Plaza, Mihogaoka, Ibaraki City, Osaka Prefecture             Senri North D Building No.709 F-term (reference) 3J552 MA02 MA12 NA01 NB01 PA02                       QA26C QB03 RA13 SA09                       SA10 SA18 SA57 TA01 VA06W                       VA32Y VA37Y VA76W VC01Z                       VC03Z

Claims (4)

[Claims] Claim: What is claimed is: 1. A predetermined shift speed is achieved by controlling the hydraulic pressure applied to each of the plurality of friction engagement elements to maintain the friction engagement element in the engaged state or the released state. To the other shift stage, the hydraulic pressure applied to the disengagement side frictional engagement element that is in the engaged state before the same gearshift and is in the released state after the same gearshift is reduced to reduce the torque transmitted by the disengagement side frictional engagement element. By causing the slip to occur and increasing the hydraulic pressure applied to the engagement side frictional engagement element that is in the released state before the same gear shift and is in the engaged state after the same gear shift. An oil pressure control device for an automatic transmission that performs the same speed change by increasing a transmission torque by an element, wherein a deviation between an actual slip amount that represents the magnitude of the actual slip that has occurred and a target slip amount is an input amount, and Same actual slip amount A feedback controller for feedback-controlling the hydraulic pressure applied to the disengagement side frictional engagement element so as to match the target slip amount, and an ideal slip amount that does not cause a shift shock continuously and gradually changes over time. A hydraulic control device for an automatic transmission, comprising: a target slip amount generating means for generating a target slip amount. 2. The hydraulic control device for an automatic transmission according to claim 1, wherein the feedback controller is a PI controller based on proportional-plus-integral control. 3. The hydraulic control device for an automatic transmission according to claim 1 or 2, wherein the target slip amount generation means provides an input that changes stepwise from 0 to a predetermined value. A hydraulic control device for an automatic transmission, comprising a reference model that outputs the target slip amount. 4. The hydraulic control device for an automatic transmission according to claim 3, further comprising an error feedback controller that inputs the difference between the actual slip amount and the output of the reference model, and the output of the error feedback controller. And a hydraulic control device for an automatic transmission configured to superimpose on the input of the feedback controller.