KR102427703B1 - Clutch control which takes hysteresis into consideration - Google Patents

Abstract

The friction clutch 105 may be operated by the slave piston 140 coupled to the master piston 130 by the hydrostatic section 120 . A method for control of a torque transmittable through a friction clutch (105) comprises controlling a position of a master piston based on a transfer function between a position of a master piston and a position of a slave piston, The position of the master piston is further controlled based on a hysteresis effect determined on the basis of the direction of movement passed through and of one of the pistons. A hysteresis effect is determined based on a plurality of support points each effective for a predetermined region of the position of the master piston.

Description

CLUTCH CONTROL WHICH TAKES HYSTERESIS INTO CONSIDERATION

The present invention relates to clutch control. In particular, the present invention relates to the control of the hydraulic actuation of a clutch, the hysteretic behavior of the actuation being taken into account.

A drivetrain in a vehicle includes a friction clutch capable of blocking torque transmission within the drivetrain. In this case, the friction clutch can be actuated hydraulically. As the operation gradually increases, the closing of the friction clutch is induced in the first embodiment, and the opening of the friction clutch is induced in the second embodiment. The resilient elements each provide a force against actuation. The hydraulic actuation includes a master cylinder having a master piston and a slave cylinder having a slave piston, the two cylinders being hydraulically coupled to each other. When the position of the master piston is changed, it acts on the slave piston and the torque transmittable via the friction clutch is correspondingly changed.

Typically, the operation of the friction clutch depends on the position of the master piston based on a transfer function. However, the elastic effect and friction in the region of the hydrostatic section induces a hysteresis effect, so that the actuation of the friction clutch is determined not only through the position of the master piston, but additionally also through the previous actuation direction of the master piston. The hysteresis effect can be dependent on the absolute position of the master piston. Also, the hysteresis effect may depend on the friction clutch used.

DE 10 2011 011 152 A1 relates to a method for controlling a friction clutch of this type.

DE 10 2013 201 261 A1 describes time-controlled compensation of hysteresis.

DE 10 2011 011 152 A1 relates to the further compensation of the aforementioned hysteresis effects.

It is an object of the present invention to provide an improved technique for the control of the torque transmittable by a friction clutch, through improved consideration of the hysteresis effect.

The present invention solves the above problems by using a method, a computer program and an apparatus having the features of the independent claims. The dependent claims specify preferred embodiments.

The friction clutch may be operated by a slave piston coupled to the master piston by a hydrostatic section. A method according to the invention for control of a torque transmittable via a friction clutch comprises controlling the position of the master piston based on a transfer function between the positions of the master piston and the slave piston, wherein the position of the master piston is In addition, it is controlled based on the hysteresis effect determined based on the position of the master piston and the direction of movement passed by one of the pistons. In this case, the hysteresis effect is determined on the basis of a plurality of support points each effective for a predetermined region of the position of the master piston.

By providing a plurality of hysteresis influences assigned to different positions of the master piston, the dependence of the hysteresis influence on the position of the master piston can be easily modeled. In this way, the trend of the hysteresis effect on the possible positions of the master piston can be easily modeled. Accordingly, the hysteresis effect can be improved and compensated for. The torque transmittable via the friction clutch can be more precisely controlled. Accordingly, driving comfort may be improved. In particular, the method can be preferably used for a dual clutch that can be connected upstream of a dual clutch transmission. In this case, one or both clutches of the dual clutch may be controlled by the above-described method so as to enable faster, smoother or more accurate switching between the input gear stages of the dual clutch transmission.

Preferably, the regions are adjacent to each other without overlapping. Thus, an apparent hysteresis effect can be easily assigned to each position of the master piston. The hysteresis effect can be determined quickly and without complexity for each position.

In another embodiment, the hysteresis effect is interpolated based on a point of support in a region assigned to that location at a given location of the master piston, and based on a point of support in one or more adjacent areas. By this interpolation, the typical course of the hysteresis effect on the possible positions of the master piston can be well modeled. In this case, the plurality of predetermined regions may be relatively small. Accordingly, memory consumption for the hysteresis effect each allocated to the region can be reduced.

In other embodiments, the points of support are not equidistant. Stated differently, in this embodiment, the regions contain different magnitudes of location differences. Thus, for example, a narrow region in which the hysteresis effect strongly changes with the position of the master piston can be selected. A small, wide area of change based on location can be selected. Thereby, an accurate modeling of the transition of the hysteresis effect with respect to the position of the master piston can be achieved without the need for many different hysteresis effects to be stored.

In a particularly preferred embodiment, the spacing between adjacent support points depends on the hysteresis effect assigned thereto. In one embodiment, the spacing between support points or the boundaries of regions is selected such that the difference between the hysteresis effects of adjacent regions is substantially equal.

In another embodiment, the stored hysteresis effect in relation to the support point can be matched even during the actuation of the friction clutch. To this end, the torque actually transmitted via the friction clutch at one position of the master piston is measured, which compares the torque determined on the basis of the position of the master piston and the hysteresis effect with the measured actual torque, the hysteresis effect being Based on the comparison, the position of the master piston is matched.

Thereby, it is possible to take account of the dynamic effects that may arise, for example, on the basis of aging or heating or hydrostatic sections of the parts of the friction clutch.

The computer program product according to the invention comprises program encoding means for the execution of the method described above when the computer program product is executed in a processing device or stored in a computer readable medium.

In the device according to the invention for control of a torque transmittable via a friction clutch, the friction clutch can be actuated by a slave piston coupled with a master piston by means of a hydrostatic section, wherein the device determines the position of the master piston and the slave piston an interface for an actuator for controlling a position of the master piston based on a transfer function between the interface, and a control device for providing a signal to the interface, wherein the control device comprises: a position of the master piston and a position of one of the pistons; It is installed to determine the hysteresis effect on the basis of the passing direction of movement and trigger the actuator according to the hysteresis effect. In this case, the control device is provided for determining the hysteresis effect on the basis of a plurality of support points each effective for a predetermined region of the position of the master piston.

Preferably, the device can be used for control of a clutch in a drive train of a vehicle. In particular, by using the device, one or two clutches of the dual clutch of the dual clutch transmission can be controlled.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a clutch system for an automobile.
FIG. 2 shows a flow chart of a method for control of the friction clutch of FIG. 1 ;
Fig. 3 shows a characteristic curve in the clutch system of Fig. 1;
Fig. 4 shows the transition of the influence of hysteresis on the position of the master piston in the clutch system of Fig. 1;

1 shows, for example, a clutch system 100 for use in particular in a drive train of a vehicle. The clutch system 100 includes a friction clutch 105 , an electro-hydraulically configured actuating device 110 in this embodiment, and a control device 112 . In view of the following description, it does not matter whether the torque that can be transmitted through the friction clutch 105 is increased when the operation with the actuating device 110 is increased or decreased. The friction clutch 105 may transmit torque in particular between the drive engine and the transmission. In one embodiment, friction clutch 105 is part of a dual clutch of a dual clutch transmission.

The actuating device 110 may be electrically controlled in the illustrated embodiment. When actuation is performed using an electrically sensory clutch pedal, it is associated with a “clutch by wire” system. The actuating device 110 includes an electric actuator 115 and a hydrostatic section 120 . The hydrostatic section 120 includes a master cylinder 125 having a master piston 130 , a slave cylinder 135 having a slave piston 140 , and a connection line 145 provided between the cylinders 125 and 135 . includes The position of the master piston 130 is transmitted by the fluid 150 from the master cylinder 125 through the connection line 145 and from the slave cylinder 135 to the slave piston 140 . The slave piston 140 is installed to operate the friction clutch 105 . Thereby, the operation of the friction clutch 105 and the torque transmittable through the friction clutch 105 are controlled via the trigger of the actuator 115 which moves the master piston 130 to a predetermined position.

The actuator 115 may be triggered via the first interface 155 using the control device 112 . A trigger of the actuator 115 or movement of the master piston 130 to a predetermined position may be performed according to a requirement that the control device 112 may accommodate via the second interface 160 . The requirement may particularly relate to the torque that must be able to be transmitted via the friction clutch 105 .

In the actual clutch system 100 , hysteresis effects appear between the position of the master piston 130 and the operation of the friction clutch 105 due to elasticity, friction loss and manufacturing accuracy. The hysteresis is presented substantially the same with respect to the position of the slave piston 140 or the hydraulic pressure of the fluid 150 . The hysteresis effect is different from the first actuation level upon movement of the master piston 130 in a first direction to a predetermined position and reaches a first actuation level upon movement of the master piston 130 in the opposite direction to the same position. act to reach a second operating level. In order for the friction clutch 105 to operate correctly, it is required to properly compensate for the hysteresis effect. To this end, it is proposed to distribute the spectrum of possible positions of the master piston 130 into regions each assigned a hysteresis effect. In particular, a plurality of fulcrum points that may be provided within the memory 165 are formed. Based on the hysteresis effect stored at the support point or stored for the regions, the hysteresis effect of the actuating device 110 for the pre-provided position of the master piston 130 can be compensated by the control device 112 .

FIG. 2 shows a flow diagram of a method 200 for control of the friction clutch 105 of FIG. 1 .

In step 205 , in particular via the second interface 160 , a requirement for the torque to be transmitted via the friction clutch 105 may be received. Based on these values, in step 210 , a desired actuation of the friction clutch 105 may be determined. In step 215 , the desired position of the master piston 130 is determined. The position may be determined based on a transfer function that assigns the positions of the master piston 130 and the slave piston 140 with respect to each other.

In step 220 , the region 170 corresponding to the predetermined position of the master piston 130 is determined. In step 225, the hysteresis effect assigned to the predetermined region is determined. In particular, the hysteresis effect may be stored in memory 165 . In one embodiment, the determination of the hysteresis effect is performed directly based on the assigned area of the position of the master piston 130 . In this case, it is desirable to provide a relatively large number of regions 170 for good resolution.

In another embodiment, which may lead to good results with a small area 170 , the hysteresis effect is interpolated to the position of the master piston 130 . To this end, the hysteresis effect of the allocated region 170 and one or more adjacent regions 170 is used as a support point for interpolation. The interpolation may be, for example, linear interpolation, quadratic interpolation, cubic interpolation, general polynomial interpolation or exponential interpolation.

In the case of the two variants, in step 235 , a predetermined position of the master piston 130 is matched based on the hysteresis effect. Then, at step 240 , the actuator 115 may be triggered to move the master piston 130 to a predetermined position.

The method 200 may be extended such that the stored hysteresis effects may be continuously matched during the operational execution of the clutch system 100 . For matching, in step 245 , the torque actually transmitted through friction clutch 105 may be determined. This can be done, for example, on the basis of sensor values, model calculations or methods that can be implemented, in particular in the inactive friction clutch 105 of the dual clutch. Alternatively, in this step, the actuation of the friction clutch 105 for a predetermined torque may be determined. In both cases, in step 250, the difference between the position of the master piston 130 determined on the basis of steps 245 and 250 and the position determinable using steps 205 to 240 can be calculated. have. Based on this difference, in step 255, the hysteresis effect assigned to the region 170 where the position of the master piston 130 is or should be matched can be matched.

Method 200 may be executed periodically. In particular, steps 205 to 240 may be periodically executed according to steps 245 to 255, respectively.

3 shows a graph 300 having a characteristic curve 305 of the clutch system 100 of FIG. 1 . The position of the master piston 130 in the horizontal direction is shown. The hydraulic pressure of the fluid 150 in the hydrostatic pressure section 120 in the vertical direction is shown. The hydraulic pressure qualitatively corresponds to the position of the slave piston 140 or the operation of the friction clutch 105 .

The characteristic curve 305 is a hysteresis loop formed based on the transfer function 302 and the hysteresis effect. In the preferred clutch system 100 , a direct relationship between the position of the master piston 130 and the position of the slave piston 140 or hydraulic pressure can be presented. However, this relationship depends on the direction 310 in which the master piston 130 moves due to elasticity, tolerance and friction. In this figure, the vertical spacing between the upper and lower portions of the hysteresis slope 305 is denoted as a hysteresis effect 315 , the absolute value of which is different at different positions of the master piston 130 .

It is therefore proposed to form regions 170 , each assigned a hysteresis effect 315 , via a possible position of the master piston 130 . A hysteresis effect 315 and, optionally, an assigned region boundary of region 170 may be provided, for example, in memory 165 . In this case, the regions 170 are preferably adjacent to each other without overlapping. If the hysteresis effect 315 changes strongly with respect to the position of the master piston 130 , the regions 170 do not need to be equally large, but may be particularly small in this position, relative to the position of the master piston 130 . The regions may be correspondingly large if the hysteresis effect 315 is only slightly changed.

FIG. 4 shows a graph 400 with a trend 405 of the hysteresis effect 315 corresponding to FIG. 3 . Similar to the figure of FIG. 3 , the position of the master piston 130 is indicated in the horizontal direction and the absolute value of the assigned hysteresis influence is indicated in the vertical direction. For each region 170 , a predetermined hysteresis effect 315 is shown at each support point 410 . In order to determine a hysteresis effect 315 with reduced granularity from the stored hysteresis effect 315 , an interpolation or extrapolation method may be performed through the support points of the known hysteresis effect 315 . The result of this interpolation is shown as transition 405 . For the determination of the trend 405, for example, linear interpolation, polynomial interpolation or other interpolation may be used. In one embodiment, the present global hysteresis effect 315 is used for interpolation. In another embodiment, interpolation is performed only between adjacent hysteresis effects 315 or around a region 170 where the position of the master piston 130 is through a predetermined number of hysteresis effects 315 .

100: clutch system
105: friction clutch
110: operating device
112: control device
115: electric actuator
120: static hydraulic section
125: master cylinder
130: master piston
135: slave cylinder
140: slave piston
145: connection line
150: fluid
155: first interface
160: second interface
165: memory
170: area
200: method
205: Receive requirement for torque to be transmitted
210: Friction clutch operation determination
215: master piston positioning
220: Determining area from location
225: Determination of the hysteresis effect in the determined area
230: Optionally, interpolation of hysteresis effects on adjacent regions
235: matching of the measured position of the master piston
240: actuator trigger
245: Determine the actual transmitted torque
250: Determination of hysteresis effect deviation
255: match of stored hysteresis effect
300: graph
302: transfer function
305: characteristic curve
310: direction
315: hysteresis effect
400: graph
405: trend
410: support point

Claims (8)

A method (200) for control of a torque transmittable through a friction clutch (105), wherein the friction clutch (105) is operated by a slave piston (140) coupled with a master piston (130) by a hydrostatic section (120) can be, the method
controlling the position of the master piston (130) based on a transfer function (302) between the position of the master piston (130) and the position of the slave piston (140);
At this time, based on the position of the master piston 130 and the hysteresis effect 115 determined based on the moving direction 310 of one of the pistons 130 and 140, the position of the master piston 130 is A further controlled, torque control method comprising:
Method (200) of torque control, characterized in that the hysteresis effect (115) is determined on the basis of a plurality of support points (410) each effective for a predetermined area (170) of the position of the master piston (130). The method (200) of claim 1, wherein the regions (170) are adjacent to each other without overlapping. The hysteresis effect (115) according to any one of the preceding claims, wherein the hysteresis effect (115) is based on a support point (410) of a region (170) assigned to said position at a position of said master piston (130) and at least one adjacent region. Torque control method (200) interpolated based on the fulcrum (410) of (170). Method (200) according to claim 1 or 2, wherein the support points (410) are not equidistant. 5. A method (200) according to claim 4, wherein the spacing between adjacent support points (410) is dependent on the hysteresis effect assigned thereto. 3. The method of claim 1 or 2,
determining the torque actually transmitted through the friction clutch (105) at one position of the master piston (130);
comparing the torque determined on the basis of the position of the master piston (130) and the hysteresis effect (115) with the measured actual torque;
and matching the hysteresis effect (115) to the position of the master piston (130) based on the comparison. A computer program product comprising program encoding means for executing a method ( 200 ) according to claim 1 , when the computer program product is executed on a processing device or stored on a computer readable medium. A device 100 for controlling a torque transmittable through a friction clutch 105 , wherein the friction clutch 105 is operated by a slave piston 140 coupled with a master piston 130 by a hydrostatic section 120 . can be, the device is
an interface (155) for an actuator for controlling the position of the master piston (130) based on a transfer function (302) between the positions of the master piston (130) and the slave piston (140);
a control device (112) for providing a signal to the interface;
At this time, the control device determines the hysteresis effect 115 based on the position of the master piston 130 and the passing direction 310 of one of the pistons 130 , 140 , and determines the hysteresis effect 115 according to the actuator according to the hysteresis effect 115 . In the torque control device installed to trigger,
The control device (112) is arranged to determine the hysteresis effect (115) on the basis of a plurality of support points (410) each effective for a predetermined area (170) of the position of the master piston (130). torque control device.

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