JPH07190184A - Speed change control device for automatic transmission - Google Patents

Abstract

PURPOSE:To make the execution of appropriate speed change operation possible even to the fluctuation of a system immediately after the start of speed change by providing a control value correcting means for computing the deviation between the actual ratio value and the target ratio value, computing the correction value to bring this deviation close to zero and outputting the correction value to the control quantity of an engagement control means. CONSTITUTION:The ratio of the rotating speed respectively detected by rotating speed detecting means 100, 101 is computed by a ratio computing means 102, and the actual ratio value, the time change rate, is outputted. A deviation computing means 104 computes the deviation between the actual ratio value and the target ratio value which is the time change rate of the target rotating speed ratio computed by a target ratio value computing means 103, and outputs it to a control value correcting means 105. The correction quantity DELTAS of an engagement control means 106 is outputted from the control value correcting means 105. The control quantity S is outputted from the engagement control means 106, and a clutch 17 and a brake 18 are controlled to execute speed change. Speed change operation can be thereby performed without generating large speed change shock.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission used in a vehicle or the like, and more particularly to a shift control device for an automatic transmission which detects and controls a rotational speed.

[0002]

2. Description of the Related Art Normally, during a gear shift operation, torque fluctuation easily occurs on the output shaft, and various measures have been proposed in the past. Therefore, in automatic transmissions often used in vehicles,
The signal detection of the shift control is detected by the rotation speed, and the deviation of the rotation speed from the target value is feedback-controlled to the target value. As known from Japanese Patent Laid-Open No. 4-337159 and Japanese Patent Laid-Open No. 63-212137, a target rotational speed value after a rotational change that changes during a gear shift operation of a transmission is calculated and determined before the rotational change. Then, some control is performed so that the difference between the value and the actual value becomes small.

[0003]

In the control of the above automatic transmission, the rotational speed of the input shaft and the rotational speed of the output shaft are monitored and controlled. If the rotation of the output of the automatic transmission rises while the rotation system composed of the torque generator and the automatic transmission is driven, the torque to be transmitted may be small, so a shift determination for switching the transmission torque is made. The shift operation is performed by lowering the gear ratio and suppressing the input shaft speed. Considering a case where the operator happens to immediately increase the rotation speed of the torque generator immediately after the start of this gear shifting operation, the load on the input shaft of this automatic transmission is light and the rotation speed is low. However, since the control to suppress the rotation is applied originally, the control to suppress the rotation increase works strongly, the engagement degree becomes large, and a sudden torque is generated on the output shaft. Is increased (in some cases, the shift control cannot be completed and there is also a problem that the shift is not performed forever). On the contrary, when the operator takes measures to reduce the rotation speed of the torque generation device immediately after the start of the gear shift, the rotation of the input shaft is lower than the target, so the control is performed to loosen the engagement degree to increase the rotation. On the contrary, this causes a problem that the shift operation is interrupted and the phenomenon of not shifting is generated.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a shift control device for an automatic transmission in which an appropriate shift operation can be carried out even with respect to the system fluctuation immediately after the start of shift as described above.

[0005]

In order to solve the above-mentioned problems, the structure of the present invention is an automatic transmission comprising frictional engagement means for connecting / disengaging / constraining a friction element and for changing and transmitting a rotational force. And a shift control device for an automatic transmission, comprising an engagement control means for detecting an input rotation speed of an input shaft and an output rotation speed of an output shaft by a rotation speed detection means and controlling the friction engagement means. In, a ratio calculating means for obtaining an actual ratio value which is a time change ratio of the rotation speed ratio between the input rotation speed and the output rotation speed, and a target ratio value which is a target time change ratio of the rotation speed ratio are calculated. Target ratio calculating means, and deviation calculating means for calculating a deviation between the actual ratio value and the target ratio value,
And a control value correction means for calculating a correction for bringing the deviation close to zero and outputting the correction amount to the control amount of the engagement control means. Further, the configuration of the related invention is characterized in that the correction calculates the deviation by PID control and sets an output of the PID control as the correction amount.

Another structure of the present invention is also characterized in that the control value correcting means is a means which is implemented by an automatic transmission of a vehicle, which is monitored and executed while the vehicle is traveling and during a shift. Still another configuration is that the engagement control means is a hydraulic control device that controls the friction element by the hydraulic pressure supplied through a hydraulic port in an automatic transmission of a vehicle.

[0007]

[Advantageous Effects of the Invention] The parameter for gear change control is not the fluctuation rate of the rotational speeds of the input shaft and the output shaft that are directly detected, but the rate of temporal change of the rotational speed ratio.
Since the speed ratio is the speed ratio itself, the control configuration is such that the time change rate of the speed ratio is calculated from the speed and the deviation of the change rate is constant. Therefore, the gear ratio changes at a predetermined change rate even when a transitional operating condition such as changing the rotation speed occurs during gear shifting, so that the gear shifting operation can be completed without increasing the gear shifting shock. Further, since the shift shock is suppressed and the shift operation is performed, optimal control can be performed with good responsiveness when the friction element is controlled by the solenoid valve.

[0008]

EXAMPLES The present invention will be described below based on specific examples. FIG. 1 shows a block diagram of a shift control device of the present invention for an automatic transmission (also called an automatic transmission) 1 using a torque converter.
The configuration diagram of the automatic transmission 1 shown in FIG. 1 shows a torque converter 11, a turbine shaft (input shaft) 12, a speed change gear 13 that is a speed change mechanism including a planetary gear, a ring gear, and an output shaft 14. It is a simplification.
The input shaft 12 and the output shaft 14 are provided with rotation sensors 100 and 101, each of which includes an electromagnetic pickup, a reed switch, a photo interrupter, or the like, to form a rotation speed detection unit. A clutch mechanism 17 that engages a rotational force and a brake mechanism 18 that suppresses rotation are provided in a speed change mechanism portion that is a friction engagement means.
Although not shown, the automatic transmission 1 has an intermediate shaft, which should be called a speed change auxiliary shaft, between the input shaft and the output shaft. It is configured to change significantly. Therefore, it is usual that there are a plurality of clutch mechanisms 17 and a plurality of brake mechanisms 18, respectively. In FIG. 1, they are collectively shown as one. In addition, these various mechanisms / devices are usually referred to as a gear box in case 1.
5 is stored, supported, and protected in 5, and is arranged in a target use environment together with a torque generator (not shown).

The rotation speeds of the respective shafts detected by the rotation speed detection means 100 and 101 are calculated as a ratio of rotation speeds (NT / NO = GE) by the ratio calculation means 102, and the time change rate is the actual value. The ratio value (ΔGE) is calculated and output. Then, in the deviation calculating means 104, the deviation ERR _N (= ΔGE − ΔGE) from the target ratio value (ΔGE _TGT ) which is the time change rate of the target rotation speed ratio calculated by the target ratio value calculating means 103
_TGT ), and the control value correction means 105 calculates and outputs the correction amount ΔS (= ΔP + ΔI + ΔD) of the engagement control means 106, and the engagement control means 106 outputs the control amount S (= S ₀ + ΔS) is output to control the clutch 17 and the brake 18, which are friction elements, to shift gears. Specifically, an operation of switching a plurality of clutches and an operation of switching a plurality of brakes are also performed, and the intermediate shafts having different gear ratios are connected to the input / output shafts. At the time of this switching, control works and is gradually switched so as not to cause a sudden torque change. The original control amount S ₀ for the friction element is calculated by the engagement control means 106 according to each use condition, and the control correction amount ΔS and the control amount S = S ₀ + ΔS are output to the friction element to be controlled. To be done.

The configuration diagram shown in FIG. 2 is an embodiment of an actual device in which the configuration of FIG. 1 is applied to a vehicle, and is a case of an electronically controlled automatic transmission 20. For convenience of description, the engine and the automatic transmission are separated from each other in FIG. 2, the intermediate shaft is also omitted, and the clutch and the brake of the friction engagement means are collectively shown as one. . The specific structure is shown in the maintenance manual for the conventional automatic transmission, and any type of automatic transmission may be used as long as it has the configuration of the present invention.

In FIG. 2, the torque of the engine 21 of the vehicle, which is a torque generator, is transmitted to the automatic transmission 20 via the torque converter 36. The turbine shaft 26 of the torque converter serves as an input shaft of the automatic transmission, and transmits torque to the output shaft 27 via an intermediate shaft (not shown). As an actual friction engagement means of the automatic transmission, a lockup clutch (direct coupling clutch) 3 for directly coupling the rotational force from the engine 21 to the turbine shaft 26 when there is no gear shifting operation is performed.
7. Also, although not specifically shown, a first clutch mechanism (C1) configured to engage the turbine rotary shaft 26 and the first intermediate shaft over both, a first intermediate shaft and a second intermediate shaft. A second clutch mechanism (C2) for engaging the and, a first brake mechanism (B1) for suppressing the rotation speed of the first intermediate shaft, a second brake mechanism (B2) for suppressing the second intermediate shaft. In some cases, a third clutch mechanism (C3) and a third brake mechanism (B3) may be provided as the third intermediate shaft. These clutches,
The gear ratio is switched by implementing a combination of the operations of the brake with the above-mentioned control amount S. The structure of each of these clutches and brakes is of a conventional structure, and a multi-plate clutch, a multi-plate brake, or a band brake that tightens a drum with a flat belt called a lining is used. A one-way clutch mechanism is often provided as a speed change mechanism. The engagement control means is a device connected to each of the above-mentioned clutches and brakes, and in the case of the hydraulic pressure supply device 33 and the hydraulic port 35, the hydraulic control system,
Further, it is composed of a hydraulic pressure distribution device such as a collective valve, an accumulator which is a hydraulic pressure adjusting means, and in the case of the electronic control type of FIG. 2, it is composed of an electromagnetic valve 34 which directly controls the hydraulic pressure to each clutch and each brake.

A control value correction means 105 and a control means 106 shown in blocks in FIG.
2, 03 and 104 are incorporated as software in an ECU (engine control unit) 25 mainly composed of a microcomputer in a ROM in the ECU as a part of program data. The ECU 25 is connected with not only the signals from the rotation sensors 30 and 31 of the input shaft 26 and the output shaft 27 but also the sensor signals such as the engine rotation sensor 24 and the throttle sensor 23 necessary for engine control, and also necessary for engine control. Various actuators (not shown) are connected so as to send an instruction signal. By the program of the ECU 25, the control value correction amount of the automatic transmission is calculated based on the signals from the rotation sensors 30 and 31 of the two rotary shafts as the control of the automatic transmission with respect to the change of the driving state during the gear shifting operation of the present invention. Then, a predetermined correction is performed on the control amount of each of the above-mentioned clutch mechanism and each brake mechanism which is the control target of the control means. Therefore, the ECU 25
Relates to all of the input shaft and output shaft rotation speed detection means and ratio calculation means, target ratio calculation means, deviation calculation means, control value correction means, and control means.

The characteristics of this correction will be described with reference to the time chart of FIG. FIG. 3 illustrates a conventional engine in which a throttle change is made while a vehicle is operating and a throttle operation is performed immediately after a shift operation of an automatic transmission is started to increase a throttle opening and an engine speed. The changes in the rotational speeds of the respective shafts and the changes in the output shaft torque in the case, in the case where the throttle is not operated at all, and in the case where the control of the present invention is performed and the throttle is operated, are schematically shown. The difference between the engine rotational speed and the rotational speed of the input shaft is the amount of slippage of the lockup clutch 37 or the torque converter 36, and the ratio of the rotational speed between the input shaft and the output shaft just means the gear ratio GE. Is 2nd and the gear ratio is 1: 1.
3 shows a third speed state in which the input shaft and the output shaft rotate at the same speed as the gear ratio becomes 1: 1 from the state of about 3 to 1.6.

If the throttle is not operated,
The rotation speed and the output shaft torque follow the locus shown by the broken line in FIG. First, when the shift judgment changes from OFF to ON (see Fig. 3
t ₀ ), the hydraulic pressure of the clutch starts increasing so as to reach the hydraulic pressure necessary for establishing the gear ratio of the third speed. When the hydraulic pressure becomes equal to or higher than a predetermined value, torque transmission is started, so that the output shaft torque temporarily decreases. Then, the input rotation speed of the reduction with increased output shaft torque starts (t ₁ in FIG. 3), the input shaft speed is controlled to run so as to decrease at a constant rate, the output shaft and the rotational speed of the input shaft When the number of revolutions of the gears coincides, the gear shifting ends (t _{4 in} FIG. 3). Actually, the entire shift process takes about 1 second, and the shift is completed so that the torque does not change significantly.
It should be noted that the torque graph of FIG. 3 is displayed by ignoring noise-like fluctuations, and the degree of inclination during the shift processing is also an appropriate value, which actually shows various fluctuations.

However, even in such a short time of about 1 second, if the throttle operation is performed before the shift change is completed (t _{2 in} FIG. 3) and the engine speed increases during the shift process, the conventional control is performed. In the system, since the control is in order to reduce the rotation, the clutch works strongly in order to suppress the increase in rotation, and in order to strengthen the engagement, the torque increases rapidly as shown by the solid line in the graphs of Fig. 3 (c) and (d). Then, the input shaft and the output shaft have the same rotational speed in a short time (t ₃ in FIG. 3), and
The target gear ratio is reached on the locus shown by the solid line in (e),
After that, the rotation speed locus corresponding to the engine rotation speed is traced.
However, in this case, as shown by the solid line in FIG. 3 (d), the fluctuation of the torque is considerably large, which causes a considerable shift shock. Incidentally, the time for the torque in the shifting process varies (t ₁ ~t ₃ or t ₁ ~t _4,) is called the inertia phase, two pairs of friction elements, i.e. the input shaft, intermediate shaft, the output shaft is sliding It is known that the torque fluctuation is occurring, and the torque fluctuation is reduced by appropriately controlling the control timing and the control amount (S above).

In contrast to the above-mentioned case, under the control of the present invention, the control is performed on the basis of the temporal change rate of the rotation speed ratio of each shaft with respect to the change of the engine rotation speed. The gear ratio changes as shown by the one-dot chain line, and the same gear ratio switching as when there is no throttle operation is realized with conventional control, and the torque and rotation speed are the same as those in Fig. 3 (c) and (d). It becomes a locus like a chain line. That is, the rotational speed ratio does not abruptly match, and the rotational speed ratio change rate is maintained at a substantially constant relationship even when the rotational speed changes, so that a large gear shift shock does not occur and the rotational speed ratio does not exceed a predetermined value ( The gear shifting operation is performed until it becomes 1: 1), and the gear shifting is completed in the same operating time as in the steady case. That is, since the control for gradually changing the speed change ratio is executed, the speed change operation can be completed without being out of control regardless of any rotation change during the speed change operation.

FIG. 4 shows the flow of processing relating to the control correction of the automatic transmission in the ECU 25 of FIG. 2, and is a configuration that is implemented when a shifting operation is performed during traveling. First, as a general processing condition, it is determined whether or not the vehicle is in a traveling state and gear shifting processing is being performed (steps 401 and 402). If the condition is not a problem, the correction value is set to 0 and the current state is ended (step 408). , 409, 410). If the gear change mode to be monitored is in question, the number of revolutions of the input shaft and the output shaft is sampled in step 403 to find the current number of revolutions ratio (gear ratio) GE. Change ΔGE is calculated. The difference between this calculated value ΔGE and the target rate of change ΔGE _TGT for obtaining the target rotation value is calculated (step 404), and this difference is set as the deviation ERR _n in step 405.
PID control correction term (ΔP: proportional term, ΔI: integral term, Δ
D: differential term) is calculated to obtain the control correction value ΔS, and the current deviation ERR _{n and the} like are stored and held (step 406) and then output (step 407). If the device that drives the clutch mechanism of the automatic transmission is an electronically controlled solenoid valve, the correction output ΔS is the valve operation amount or regulator operation amount that determines the hydraulic pressure value in the electromagnetic drive duty ratio adjustment or hydraulic control. Is. This control amount adjusts the hydraulic pressure that determines the engaged, restrained, and released states of the clutches (C1 to C3) and the brakes (B1 to B3) that are the final engagement control means.

The calculation of the PID control in step 405 is performed by a microcomputer (ECU) and is therefore a digital value calculation, and the proportional constant K _j (j = P, I, D) of each term is determined by the torque generator to be used. A predetermined set value is selected according to the characteristic. Further, since this control including sampling depends on the processing speed of the microcomputer, even if the monitoring target is about 1 second, which is the actual operation time of the shift operation, it is sufficiently sampled and controlled. . Note that the processing of the flowchart shown here is the same as that of the shift control 1
The control is repeatedly performed for each control, and if the shift determination is not made, it is determined that there is no need to correct the shift, and the control is not performed.

In the above embodiment, the proportional constant of the PID control shown in step 405 is shown in the flowchart of FIG. 4 as a constant value, but since these values are processed by the ECU 25, they may follow operating conditions if necessary. Alternatively, the constant may be determined by a map, and the correction amount may be obtained based on the result of appropriate deformation calculation of each PID calculation amount. Furthermore, in the present embodiment, an example of control by PID control is shown, but a model is created for the rotation speed ratio (gear ratio) change rate ΔGE, that is, the GE inclination is calculated by the model calculation means at an appropriate time under a predetermined condition. Even if it is configured in advance to be moved up and down in advance and controlled by the model, it will not be affected by the change in the rotation speed of the input shaft and output shaft, and the same control result will be obtained. Have an effect. This model may be a simple straight line type or a non-linear type with smooth switching.

As described above, according to the control means of the present invention, the gear shift operation does not follow under any driving condition during the gear shift, and there is no possibility of being out of control as in the conventional case. (EN) Provided is a shift control device for an automatic transmission that does not cause

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a shift control device for an automatic transmission to which the present invention is applied.

FIG. 2 is a system diagram of an automatic transmission for a vehicle using an electronically controlled solenoid valve that is the specific control device of FIG.

FIG. 3 is a time chart diagram when the number of rotations is increased by the operator immediately after the start of the gear shift operation.

FIG. 4 is a flowchart showing how to perform shift control correction control.

[Explanation of symbols]

1, 20 Automatic transmission 11, 36 Torque converter 12, 26 Input shaft (turbine shaft) 13 Transmission mechanism (planetary gear, ring gear) 14, 27 Output shaft 15 Case (gear box) 17, 28 Friction engagement means (friction element , Clutch) 18, 29 friction engagement means (friction element, brake) 100 input shaft rotation speed detection means (rotation speed sensor and sampling) 101 output shaft rotation speed detection means (rotation speed sensor and sampling) 105 control value correction means 106 Engagement control means 21 Engine (torque generator) 23 Throttle sensor 24 Engine rotation sensor 25 ECU (control means, control value correction means, each calculation means, each detection means) 30 Output shaft rotation sensor (rotation speed detection means) 31 Input Shaft rotation sensor (rotation speed detection means) 33 Hydraulic pressure supply device (engagement control means) 34 Electric The valve (engagement control means) 35 Hydraulic port (engagement control means) 37 lock-up clutch (direct coupling clutch)

Claims (4)

[Claims] 1. An automatic transmission comprising frictional engagement means for connecting, releasing, and restraining frictional elements, and for changing and transmitting rotational force, the input rotational speed of an input shaft and the output rotational speed of an output shaft. In a gear shift control device for an automatic transmission, which comprises an engagement control means for detecting the number of revolutions by means of a revolution speed detection means and controlling the frictional engagement means, a rotation speed ratio of the input rotation speed and the output rotation speed A ratio calculating means for obtaining an actual ratio value which is a time change rate, a target ratio calculating means for calculating a target ratio value which is a target time change rate of the rotation speed ratio, a real ratio value and the target ratio value An automatic transmission characterized by having a deviation calculating means for calculating the deviation of the deviation, and a control value correcting means for calculating a correction for bringing the deviation close to zero and outputting the correction amount to the control amount of the engagement control means. Shift control device. 2. The shift control device for an automatic transmission according to claim 1, wherein in the correction, the deviation is calculated by PID control, and an output of the PID control is used as the correction amount. 3. The automatic transmission according to claim 1, wherein the control value correction means is an automatic transmission of a vehicle, and is a means that is monitored and implemented while the vehicle is running and during a shift. Gear shift control device. 4. The engagement control means is a hydraulic control device for controlling the friction element by hydraulic pressure supplied through a hydraulic port in an automatic transmission of a vehicle.
A shift control device for an automatic transmission as set forth in.