JPH0242249A - Speed change control device of continuous transmission - Google Patents

Abstract

PURPOSE:To prevent overshoot in case the target value is constant by deciding the shifting speed with a shift speed scanning part on the basis of deviation of actual gear ratio from the target gear ratio and the variation of this deviation. CONSTITUTION:Actual gear ratio (i) is calculated by a calculator part 40 with signals given from a primary and a secondary pulley revolving speed sensor 21, 22, while a target primary pulley revolving speed computed at a scanning part 41 from the degree of throttle opening given by a sensor 29 and the actual gear ratio (i), and further the target gear ratio reckoned by a second calculator part 42. A third calculator part 43 determines the deviation of actual gear ratio (i) from the target gear ratio is while another calculator part 44 obtains the variation of the deviation, and on the basis of these calculations, a scanning part 45 determines the shift speed di/dt by means of map scanning, and a solenoid valve 48 is driven with corresponding duty ratio D. This prevents overshoot etc. in case the target value is constant.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a shift control device that controls the shift speed based on the gear ratio and rotational speed in a belt-type continuously variable transmission for vehicles. This relates to speed change control determined based on the change in deviation.

[Conventional technology]

In this type of continuously variable transmission, it has been considered to perform speed change control so as to not only follow a transient state but also have good convergence so as to prevent overshooting, hunting, etc. For this reason, for example, the deviation between the target value of the target gear ratio and the actual value of the actual gear ratio. It has been proposed to control the shift speed by determining the operation amount as the shift speed using factors that take into account convergence. There is a tendency to further correct and optimize the target value and operation amount depending on various special driving conditions and the state of the engine or drive system. Conventionally, regarding speed change control of the above-mentioned continuously variable transmission, there is a prior art disclosed in, for example, Japanese Patent Laid-Open No. 60-98251. Here, in the method of controlling the follow-up control for the target value Ne' of the engine rotational speed Ne using the speed ratio e, multiple target values are determined for the throttle opening θ, etc., and multiple target values are set at the start and end of acceleration. Control is shown to select one.

[Problem to be solved by the invention]

By the way, in the prior art described above, in addition to the actual Ne and the target value Ne', the target value Ne' is changed by selecting either the steady state or the acceleration state depending on the operating conditions such as the throttle opening θ. Therefore, while the followability is improved during acceleration, for example, the convergence may be deteriorated. Furthermore, since a plurality of target values Ne' are set and selected, the control system becomes complicated. Therefore, in order to always achieve good followability and convergence and to simplify the control system, the following method has been proposed by the applicant of the present invention. That is, the target value i of the target gear ratio
The following element is determined by the deviation (is-i) between s and the actual value 1 of the actual speed ratio, and the change dis/d in the target value is of the target speed ratio
Determine the convergence element by t, and add both to get the shift speed di/d
t is calculated, and based on this, the operating amount is determined and controlled. However, according to this, the convergence element is the target value I
The actual speed ratio is set based on the change in S only! ! i
Therefore, especially when the target @iS is constant, the shift speed di/dt is equal to (is-i) of the following element, that is, the actual value l
overshoot, etc., is likely to occur. Therefore, it is desirable that the convergence element determines the target value IS and the actual value i using parameters, and that even when the target value IS is constant, the shifting speed is controlled by both the follow-up element and the convergence element. The present invention has been made in view of the above, and its purpose is to further improve convergence in a control system that controls speed change using a follow-up element and a convergence element based on a target value and an actual value. An object of the present invention is to provide a speed change control device for a continuously variable transmission that is capable of performing the following steps.

[Means to solve the problem]

In order to achieve the above object, the speed change control device of the present invention inputs signals output from a primary pulley rotation speed sensor, a secondary pulley rotation speed sensor, and a throttle opening sensor to determine the actual speed ratio of a continuously variable transmission. In a control unit for a continuously variable transmission having an actual gear ratio calculation unit that calculates an actual gear ratio and a target gear ratio calculation unit that calculates a target gear ratio, a target value based on a signal from the target gear ratio calculation unit and the actual gear ratio are calculated. a deviation calculation unit that calculates the deviation from the actual value based on the signal from the calculation unit; and a deviation change amount that inputs the signal from the deviation calculation unit and calculates the change in the deviation between the target gear ratio and the actual gear ratio. The present invention includes a calculation section, and a shift speed search section that determines a shift speed based on signals from the deviation calculation section and the deviation change calculation section.

[For production]

Based on the above configuration, the shift speed is always determined by a follow-up element based on the deviation between the target value and the actual value, and a convergence element for the change in the deviation, and by the operation amount based on the shift speed,
Shift control is performed so that the actual value follows and converges with the target value. Since the convergence element is the change in the deviation between the target value and the actual value, even if the target value is constant, it converges without overshooting due to the convergence state of the actual value, and at the point of convergence when the deviation is zero, the actual value with respect to the target value It will control to a stable convergence state depending on the convergence status of the value.

【Example】

Embodiments of the present invention will be described below based on the drawings. Referring to FIG. 1, the overall configuration of a drive system that combines an electromagnetic clutch and a belt-type continuously variable transmission will be described. The engine 1 is continuously variable 31 through an electromagnetic clutch 21 such as an electromagnetic powder type, and a forward/reverse switching device 3. 5. Connected to the machine 4, and connected to the continuously variable transmission 4. Output shaft 6. The transmission is configured to be transmitted to drive wheels 9 via a differential gear 7 and an axle 8. The electromagnetic powder clutch 2 has a drive member 2a on the engine crankshaft 1°, and a driven member 2b on the input shaft 11 with a clutch coil 2c. Then, due to the clutch current flowing through the clutch coil 2C, both members 2a,
Electromagnetic powder is bonded and accumulated in the gap between the parts 2b and 2b, and the resulting bonding force variably controls clutch engagement/disengagement and clutch torque. The forward/reverse switching device 3 is configured in a synchronous meshing manner between an input shaft 11 and a transmission main shaft 12 by gears, a hub, or a sleeve, and has at least a forward position where the input shaft 11 is directly connected to the main shaft 12, and a forward position where the input shaft 11 is directly connected to the main shaft 12. 11 is reversed and transmitted to the main shaft 12. 'The continuously variable transmission 4 has a main shaft 12 and a subshaft 13 arranged parallel to the main shaft 12. The main shaft 12 is provided with a hydraulic cylinder 14a, and a primary pulley 14 with variable pulley spacing is connected to the subshaft 1.
3 is similarly provided with a secondary pulley 15 equipped with a hydraulic cylinder 15a. Further, a drive belt 16 is wound around both pulleys 14 and 15, and both cylinders 14a,
15a is configured as a hydraulic control circuit 17. Line pressure corresponding to the transmitted torque is supplied to both cylinders 14a and 15a to apply a pulley pressing force, and the primary pressure causes the drive belt 16 to wrap around the pulley 14.15 steplessly by changing the diameter ratio. It is configured to perform speed change control. Next, the electronic control system of the electromagnetic powder clutch 2 and the continuously variable transmission 4 will be explained. Engine speed sensor 19 for engine 1. Continuously variable transmission 4 primary pulley rotation speed sensor old, secondary pulley rotation speed sensor 22. It has sensors 23 and 24 that detect the operating status of the air conditioner and choke. Further, the operating system shift lever 25 is mechanically connected to the forward/reverse switching device 3, and is equipped with a shift position sensor 26 that detects each range of reverse (R), drive (D), and sporty drive (Ds). has. Further, the accelerator pedal 27 has an accelerator switch 28 for detecting the accelerator depression state, and a throttle opening sensor 29 for opening the throttle valve. The various signals from the switches and sensors are input to the electronic control unit 20 and processed by software using a microcomputer or the like. Then, the clutch control signal output from the electronic control unit 20 is input to the electromagnetic clutch 2, and the shift control signal and line pressure control signal are input to the hydraulic control circuit 17 of the continuously variable transmission 4 to perform each control operation. There is. Referring to FIG. 2, the electromagnetic clutch control system and continuously variable speed control system of the control unit 20 will be explained. First, the electromagnetic clutch control system includes a reverse excitation mode determination section 32 to which the engine speed Ne and signals of parking (P) and neutral (N) ranges other than R, D, and DS of the shift position sensor 26 are input. , for example Ne <3
In the case of 00 rpm or in the P or N range, it is determined to be the reverse excitation mode, and the output determination section 33 causes a small current to flow in the opposite direction to the normal one. Then, the residual magnetism of the electromagnetic clutch 2 is removed and the electromagnetic clutch 2 is completely released. Further, an energization mode determination unit 34 receives the determination output signal of the reverse excitation mode determination unit 32, the depression signal of the accelerator switch 28, and the rotation (hereinafter referred to as vehicle speed ■) signal of the secondary pulley rotation speed sensor 22.
This discrimination signal determines the driving state such as starting.
Starting mode current setting section 35. It is input to the drag mode current setting section 3G and the direct connection mode current setting section 37. The starting mode current setting unit 35 separately sets starting characteristics in relation to the engine rotation speed Ne, etc. in the case of normal starting or starting using an air conditioner or a choke. Then, throttle opening θ and vehicle speed ■. The clutch current is set by correcting the starting characteristics according to each driving range of R, D, and DS. The drag mode current setting unit 36 determines a slight drag current when the accelerator is released at low vehicle speed in each of the R, D, and Ds ranges, and generates a drag torque in the electromagnetic clutch 2 to reduce play in the belt and drive system. , to perform a smooth start. In this mode, the current is set to zero until just before the vehicle stops after the clutch is released in the D range, to ensure coasting performance. The direct-coupling mode current setting unit 37 determines the direct-coupling current based on the relationship between the vehicle speed V and the throttle opening θ in each range of R, D, and Ds, fully engages the electromagnetic clutch 2, and saves power in the engaged state. . The output signals of these current setting units 35, 36, and 37 are input to the output determining unit 33, and the clutch current is determined according to the instructions thereof. Next, to describe the variable speed control system of continuously variable transmission control, the primary rotation speed Nl of the primary pulley rotation speed sensor 21 and the secondary pulley rotation speed sensor 22) and the secondary rotation speed Ns are input to the actual speed ratio calculation unit 40, Actual speed ratio 1 is calculated from actual speed ratio 1=Np/Ns. This actual gear ratio i and the throttle opening θ of the throttle opening sensor 29 are input to the target primary rotation speed search unit 41, and R
, D, and Ds based on the shift pattern for each range.
The target primary rotation speed NPD is searched using the map. Target primary rotation speed NPD and secondary rotation speed N
s is input to the target gear ratio calculating section 42, and the target gear ratio is is calculated by s=NPD/Ns. These target gear ratio IS and actual gear ratio i are input to the deviation calculating section 43, and the deviation (is-i) between the two is calculated.
This deviation is input to the deviation change calculating section 44 to calculate the deviation change d(is −i)/dt. Furthermore, these surface differences (is-i) and its variation d(is-i)/dt are input to the shifting speed search section 45, and the shifting distance di/dt is calculated from these factors as follows. do. di/dt = f((is-i), d(is-i)
/dt) Here, 1s-i is a follower element, d(is-i)
/dt is a convergence element, and the shift speed di/dt is determined by searching a map of the relationship between the two. In this case, the map is
The deviation between the target gear ratio is and the actual gear ratio i is positive and large (PB)
. Positive and medium (PM), positive and small (PB), zero (20). Using a negative value of small (NS), a negative value of medium (NM), a negative value of large (NB), and a predetermined value (K), the result is as shown in FIG. That is, at least l5-1≧Q, d(is)/dt≦0
and 1s-i≦01d(is-i
)/dt≧O upshift region and shift speed di/d
t is determined. Deviation change d(is −i)/dt=
If it is 0, the deviation (is-i) is PB, PM, PS. The value of ... is 3N! The speed di/dt is also directly proportional to the values of PB, PM, PS, etc. In addition, when the law difference 1s-i=o, the deviation change d(is-i)
When /dt is PB, PM, PS, ..., the shifting speed d1/dt is directly proportional to PB, PM, PS, ...
・Set to the value of . Then, the shift speed di/dt is set so as to gradually change when the deviation 1s-i and the difference change d(is-i)/dt are near zero. The shift speed di/dt and the actual gear ratio 1 are input to the duty ratio search section 46. Here, since the duty ratio of the manipulated variable is set according to the relationship D = f (di/dt, i), the duty ratio in upshift and downshift is equal to the shift speed and actual gear ratio, that is, di/d
The search is performed using the map of t-i. The value of the duty ratio of this operation amount is outputted to the shift speed control solenoid valve 48 of the hydraulic control circuit 17 via the drive unit 47. Next, the line pressure control system for continuously variable transmission control will be described. Engine speed sensor 19. Throttle opening sensor 2
The engine torque retrieval unit 50 receives the engine rotational speed Ne of 9 and the throttle opening θ, and calculates the engine torque T from the torque characteristic map of θ-Ne. The engine torque T and the signal of the actual gear ratio i from the actual gear ratio calculation unit 40 are as follows:
The target line pressure PL is input to the target line pressure setting unit 51 and is determined by the product of the required line pressure according to the engine torque and the actual gear ratio 1.
Define d. On the other hand, since the maximum line pressure value changes as the pump discharge pressure changes depending on the engine speed, the maximum line pressure search unit 52 inputs the engine speed Ne and the actual gear ratio i in order to detect this fluctuation state. and N
The maximum line pressure P LlaX is determined from the map of e-1. The target line pressure PLd and the maximum line pressure P LlaX are input to the reduced pressure value calculation unit 53, and the maximum line pressure P LlaX is
line pressure PLR at the ratio of target line pressure Pl-d to
This is input to the duty ratio search section 54 to determine the duty ratio according to the line pressure PLR. The duty signal is configured to be outputted to the line pressure control solenoid valve 56 via the drive section 55. Next, the operation of the shift control device for the continuously variable transmission configured as described above will be explained. First, power from the engine 1 corresponding to the depression of the accelerator is input to the primary pulley 14 of the continuously variable transmission 4 via the magnetic latch 21 and forward/reverse switching device 3, and the power is input to the primary pulley 14 of the continuously variable transmission 4.
6. The power that has been changed by the secondary pulley 15 is output, and this is transmitted to the drive shaft 9 side, thereby causing the vehicle to run. During the above-mentioned running, the target line pressure is set to be larger as the engine torque T is larger in the lower speed gear where the value of the actual gear ratio 1 is larger, and a duty signal corresponding to this is input to the solenoid valve 56 to generate the control pressure. By controlling the line pressure using the averaged pressure, the line pressure PL is increased. Then, as the shift to a high speed gear occurs, the gear ratio i becomes smaller, and as the engine torque T also becomes smaller, the line pressure PL is controlled to decrease by the same effect, and in this way, the transmission by the drive belt 16 is always A pulley push that corresponds to a torque exerts a force. The line pressure PL is always supplied to the secondary cylinder 15a, and is supplied to the primary cylinder 14a by a speed change control valve (not shown) using the control pressure of the solenoid valve 48.
By supplying and draining oil to and from the engine, the speed change speed is controlled, and this will be explained below. First, the primary boolean rotation speed sensor 21. Secondary boolean rotation speed sensor 22 and throttle opening sensor 2
The signals Np, Ns, and θ from 9 are read, and the actual gear ratio calculation unit 40 of the control unit 20 calculates the actual gear ratio (.In addition, the target primary rotation speed search unit 41 calculates the actual gear ratio i, throttle opening θ Once the target primary rotation speed NPD is searched by the map, the target gear ratio calculation unit 42
Then, a target gear ratio is corresponding to this target primary rotation speed NPD is calculated. Therefore, in the region where the primary rotation speed is constant, the target gear ratio is is the same fixed value as calculated by the Ns-θ method, but in the region where the primary rotation speed is variable, the target gear ratio is is the same as that calculated by the Ns-θ method. Compared to the one calculated by the method, the target speed ratio is is set to be offset to the lower gear side, and furthermore, the target speed ratio is becomes a value that changes by itself. The deviation between these actual gear ratio i and target gear ratio IS (is-1
) and the deviation change d[is −i)/dt is used to find the shift speed di/dt in the shift speed search unit 45. Then, the duty ratio search unit 46 searches for the duty ratio based on the shift speed di/dt and the actual gear ratio 1. The duty signal is input to the solenoid valve 48 to generate a pulse-like control pressure, thereby repeatedly operating the speed change control valve in two positions: oil supply and oil drain. Here, when the duty ratio becomes smaller, the shift speed control valve operates for a longer time in the refueling position due to the off time, and the primary cylinder 14a is refueled, thus upshifting. On the other hand, when the duty ratio increases, the operating time at the oil draining position becomes longer due to the on-time, and the first primary cylinder 14a drains oil, thereby causing a downshift. Since the gear shift speed di/dt in this case corresponds to the change in the duty ratio, if the deviation between the target gear ratio IS and the actual gear ratio 1 is small, the change in the duty ratio is small and the flow rate of the primary cylinder 14a changes. Because there is less, the gear shifting speed becomes slower. On the other hand, as the deviation between the target gear ratio is and the actual gear ratio i increases, the change in the flow rate of the primary cylinder 14a increases due to a change in the duty ratio, and the shift speed becomes longer. In this way, the gears are shifted steplessly by upshifting or downshifting while changing the gearshift speed over the entire gearshift range between the low gear and the high gear. Now, to describe the downshift control when the accelerator is depressed as shown in FIG. 4(a) to C), if the deviation 1s-i between the initial target value is and the actual value i is large, A shift speed di/dt corresponding to the value of i is searched, and the actual value i immediately follows the target value S by controlling the shift according to the duty ratio of this shift speed di/dt. Then, the deviation converges at 1s-i=o, but in this case, it is further controlled by the element of deviation change d(is-i)/dt,
As shown in Figure 4(a), the deviation change d(is −i)/d
If t rapidly converges at NB and overshoot is likely to occur, the shift speed di/dt will be adjusted to NB according to the map in Figure 3.
is set to Due to this change, the actual value i smoothly converges toward the upshift direction, as shown by the broken line. As shown in Figure 4(b), the deviation change d(is −i)/dt is N
In a situation where M converges more slowly than mentioned above, the shift speed di/d
t is set to NM by the map in Fig. 3, and Fig. 4 (C
), the deviation change d(is −i)/dt is further N
In a situation where S converges more slowly than mentioned above, the shift speed di/d
t is set to NS according to the map shown in FIG. 3, and convergence occurs smoothly while being upshifted. On the other hand, regarding the upshift control shown in Fig. 4 (a゛) or Co), as shown in Fig. 4 (a゛), the inertia variation d(is - i)/dt rapidly converges at PB. In this case, the shift speed di/dt is set to PB according to the map shown in FIG. 3, and the actual value i is greatly corrected in the downshift direction as shown by the broken line. If the deviation change d(is - i)/dt is PM as shown in Fig. 4 (bo), the shift speed di/d
If t is PM according to the map in Fig. 3, and the deviation change d(is - i)/dt is ps as shown in Fig. 4 (Co), the shift speed idi/dt is converted to PS according to the map in Fig. 3. set and converges smoothly as well. Next, in FIG. 5(a) to C), the target value is
and the actual value j are parallel and the deviation change d(is −i)/d
The case where t=0 will be described. At this time, if the deviation (is-i) is PB as shown in FIG. 5(a), the shift speed di
/dt is set to the same PB according to the map shown in Fig. 3, and as a result, the actual value i is significantly downshifted to the target value IS.
converges to. When the deviation (is-i) is PM as shown in Fig. 5(b) and the deviation (IS-1) is PS as shown in Fig. 5(C), the shift speed di/dt is also Therefore, the same PM and PS are set, and the actual value quickly converges to the target value is without overshooting. Deviation (is-
In the upshift region where i) is negative, control is done in exactly the same way. Although one embodiment of the present invention has been described above, the present invention can also be applied to cases other than gear ratios as objects to be controlled.

【Effect of the invention】

As described above, according to the present invention, in a control system that makes the actual value follow the target value by the deviation between the two, and furthermore performs speed change control so as to converge the two, not only the target value but also the actual value is used as a convergence element. Since the value is also added to the setting, it is possible to prevent overshoot etc. when the target value is constant. Furthermore, the convergence element is determined by the change in deviation, and the shift speed is determined by a map of the change with the deviation, so that control is performed so that convergence occurs most quickly and smoothly when the deviation or its change is zero. This eliminates convergence defects and greatly improves convergence.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram showing an embodiment of a shift control device for a continuously variable transmission of the present invention, Fig. 2 is a block diagram of the entire control system, Fig. 3 is a diagram showing a shift speed search map, and Fig. 4 is a diagram showing a shift speed search map. Diagram (a)
or C) is a diagram showing a convergence state of downshift control;
fa') or Co) shows the convergence state of upshift. FIGS. 5(a) to 5C) show the convergence state when the target value and the actual value are parallel. 4... Continuously variable transmission, 20... Control unit, 40...
...Actual speed ratio calculation unit, 42...Target speed ratio calculation unit, 4
3... Deviation calculation unit, 44... Deviation change calculation unit, 4
5...Shift speed search section

Claims (2)

[Claims] (1) An actual gear ratio calculation unit that calculates the actual gear ratio of the continuously variable transmission by inputting the signals output by the primary pulley rotation speed sensor, the secondary pulley rotation speed sensor, and the throttle opening sensor, and the target gear ratio. In a control unit of a continuously variable transmission having a target gear ratio calculation unit that calculates a deviation between a target value based on a signal from the target gear ratio calculation unit and an actual value based on a signal from the actual gear ratio calculation unit, a deviation calculation unit that calculates the deviation, a deviation change calculation unit that inputs the signal from the deviation calculation unit and calculates the change in the deviation between the target gear ratio and the actual gear ratio, and the deviation calculation unit and the deviation change calculation unit. 1. A shift control device for a continuously variable transmission, comprising: a shift speed search section that determines a shift speed based on a signal from a calculation section. (2) When the change in the deviation calculated by the deviation change calculation section is zero, the speed change speed is determined in direct proportion to the deviation, and when the deviation is zero, 2. The shift control device for a continuously variable transmission according to claim 1, wherein the shift speed is set to be determined in direct proportion to the deviation change.