CN111757994B

CN111757994B - Device and method for controlling a clutch in a drive train, and drive train

Info

Publication number: CN111757994B
Application number: CN201880090146.6A
Authority: CN
Inventors: T·M·H·K·拉海伊; R·H·M·提多拉尔; K·S·赖斯
Original assignee: Nanjing Bangqi Automatic Transmission Co ltd
Current assignee: Nanjing Bangqi Automatic Transmission Co ltd
Priority date: 2017-12-29
Filing date: 2018-12-20
Publication date: 2022-10-14
Anticipated expiration: 2038-12-20
Also published as: BE1025861A9; WO2019129663A1; CN111757994A; BE1025861B9; BE1025861B1; BE1025861A1

Abstract

A method for controlling a clutch in a transmission system is provided. The clutch is controllable by a control signal to selectively assume one of a disconnect mode of operation, a controlled slip mode of operation, and a lock-up mode of operation. The method comprises the following steps: using a feedback control component to generate a control signal that maintains the clutch in a stable slip operating mode, evaluating at least a first representative value of the control signal and a second representative value of transmission fluid temperature in the clutch while maintaining the clutch in the stable slip operating mode; the open-loop control component is used to generate a control signal that maintains the clutch in the locked mode of operation, wherein the control signal provided by the open-loop controller is dependent upon at least the evaluated first and second representative values.

Description

Device and method for controlling a clutch in a drive train, and drive train

Background

The present invention relates to a control apparatus for a power train.

The invention further relates to a method for controlling a powertrain.

The invention further relates to a powertrain comprising such a control device.

The powertrain in a continuously variable transmission typically includes a torque converter/lock-up clutch (TC/LUC), a forward-neutral-reverse clutch (DNR), and a transmission. The transmission is typically provided as a drive belt mechanically coupling two pulleys. In the normal driving phase, all elements of the powertrain are preferably operated in a non-slip operating mode, since slip operation may result in energy losses and thereby negatively impact fuel economy. Especially slipping operating modes of the transmission should be avoided, as this may lead to wear of the drive belt and/or the pulleys. This can be achieved by a high level of clamping. On the other hand, the clamping level, in particular of the drive belt, should not be set too high, since this would mean that the charging system supply does not necessarily need a high drive current to maintain this high clamping level, which also does not contribute to fuel economy. Additionally, increasing the level of clamping above that required for slip-free operation of the transmission tends to increase the transmission losses of the transmission and the wear of the transmission due to increased friction. Furthermore, it should be taken into account that the driving conditions may change suddenly, for example due to road damage or rapid braking of the vehicle. To avoid slippage of the transmission under such conditions, the LUC torque capacity should be set to a value lower than the torque capacity of the transmission. It is thereby achieved that the TC/LUC acts as a fuse in the case of an unexpectedly high torque to be transmitted, which absorbs the unexpected torque by slipping, thus avoiding slipping of the transmission. The LUC, which is typically designed as a wet clutch, can be operated in a continuous slip mode of operation without damage. The response characteristics of the various elements in the powertrain are also dependent upon their operating temperatures. These may vary to a large extent depending on the time elapsed since the vehicle was started. Especially for clutches, this depends to a large extent on their mode of operation. In the slipping mode of operation, the operating temperature increases to a large extent due to energy dissipation. The response characteristics of the clutch may also depend on other conditions. Also, the response characteristics change over time due to wear during use.

SUMMARY

A first object is to provide a control device that enables appropriate control of a clutch taking into account temperature variations and changes in characteristics of the clutch over the life.

A second object is to provide a powertrain comprising an improved control device.

A second object is to provide a control method arranged to control the powertrain in this way.

According to the first object, a control device according to claim 1 is provided. The control apparatus as claimed is configured for controlling a clutch in a driveline, for example, a lock-up clutch as used in a torque converter lock-up clutch assembly, or a clutch as used in a forward-neutral-reverse DNR assembly. The clutch is controllable by a control signal from the control device to selectively assume one of a disconnect mode of operation, a controlled slip mode of operation and a lock-up mode of operation. The control device includes an open-loop controller having a simulation module and an update module for updating the simulation module. The open-loop controller determines a control signal for controlling the clutch based on the estimated clutch response characteristic (e.g., based on manufacturer specifications). The control apparatus also includes a feedback controller to provide a control signal component for controlling the clutch based on the observed clutch response. The observed response may, for example, include a slip rate of the clutch. The feedback controller may further base its response on a derived quantity, such as an estimate of the torque delivered.

It is noted that the feedback controller (also referred to as a closed-loop controller) and the feedforward controller (also referred to as an open-loop controller) may share certain components. For example, the feedback controller and the feedforward controller may share an amplifier to provide a control signal of sufficient strength. As another example, the feedback controller and the feedforward controller may share a selection element that selects a signal from a particular feedback element or a particular feedforward element. Accordingly, the feedback controller and the feedforward controller may also be considered to be the same controller in a feedback configuration (closed-loop configuration) and a feedforward configuration (open-loop configuration), respectively. Further, in a feedback configuration, the control signal may be constructed by a superposition of the feedforward-based component and the feedback-based component.

The control device has at least a first control mode in which the feedback controller is caused to be able to generate a control signal in accordance with a predetermined specification, the control signal maintaining the clutch in a stable slip operating mode, for example a mode in which the difference between the input and output rotational speeds is maintained at a constant value, or a mode in which the ratio between the input and output rotational speeds is maintained at a constant value. In this steady slip operating mode, the control device evaluates at least a first representative value of the control signal by which it maintains that operating mode, and also evaluates a second representative value of the temperature of the transmission fluid in the clutch. The control device updates the simulation module with the representative feedback signal value and one or more corresponding representative state values, such as a representative value of transmission fluid temperature.

The control device further has at least a second control mode in which the feedback controller is disabled and the open-loop controller generates a control signal that maintains the clutch in the locked mode of operation, wherein the control signal depends at least on the evaluated first and second representative values, i.e. the control signal has a value that depends on an emulated signal value of an emulated signal generated by the updated emulation module, the emulated signal value depending on an actual value of the one or more clutch status signals.

In an embodiment of the control device, the feedback controller comprises an integral action control component, and the representative feedback signal value is determined using said integral action control component. This is advantageous because the value of the output signal provided by the integral action control component can be used directly as an average value representative of the value of the feedback signal.

In an embodiment, the simulation module is updated in the first control mode to reduce a difference between a value of the simulation signal associated with the one or more respective representative state values by the simulation module and the characteristic feedback control signal value. The associated value is a simulated signal value generated by the simulation module based on the respective representative state value, i.e. the value necessary to obtain the controlled slip operation mode in accordance with the current state of the simulation model as implemented in the simulation module. This may be the value of the control signal by which the clutch is set in its controlled slip mode of operation, or may be the value by which another signal has to be modified to obtain the value of the control signal by which the clutch is expected to be set in its controlled slip mode of operation. The characteristic feedback control signal value is indicative of a signal value of the control signal for which the controlled slip operation mode is actually observed, or a signal value that has to be added to another signal to obtain a control signal value for which the controlled slip operation mode is actually observed.

In an embodiment, the difference is partially reduced at the time of updating, i.e. the updating is done in a conservative manner, so that observed fluctuations in the signal do not lead to an unstable behavior of the controlled clutch.

According to a second aspect, an improved powertrain for use in a continuously variable transmission system is provided that includes a torque converter/lock-up clutch (TC/LUC), a forward-neutral-reverse clutch (DNR) 0 and a transmission. The improved powertrain may comprise an embodiment of the control device for controlling the lock-up clutch as claimed and/or an embodiment of the control device for controlling the DNR clutch as claimed.

According to a third aspect, there is provided a method for controlling a clutch in a transmission system, the clutch being controllable by a control signal to selectively assume one of a disconnect mode of operation, a controlled slip mode of operation and a lock-up mode of operation, the method comprising:

in a closed-loop control mode, generating a feedback control signal based on an observed clutch response, the feedback control signal maintaining the clutch in a stable slip operating mode;

evaluating a representative control signal value of the feedback control signal by which the clutch is maintained in the steady slip operating mode, and one or more corresponding representative state values of one or more clutch state signals indicative of clutch state; updating a simulation model indicative of the estimated clutch response characteristic based on the evaluated representative control signal value and the one or more respective representative state values;

in the open-loop control mode, the updated simulation model is used to generate open-loop control signals as a function of respective actual values of the one or more clutch state signals to maintain the clutch in its locked mode of operation.

Brief Description of Drawings

These and other aspects are described in more detail with reference to the accompanying drawings. Wherein:

fig. 1 schematically shows a powertrain in a vehicle;

FIG. 2 illustrates aspects of the control device in more detail;

FIG. 3A illustrates an embodiment of a control device in a first control mode;

FIG. 3B illustrates the embodiment of the control device in a second control mode;

FIG. 4 illustrates a first embodiment of a method of controlling a clutch;

5A-5E depict various signals and status indicators during execution of the first embodiment of the method;

FIG. 6A illustrates another embodiment of the control device in a first control mode;

FIG. 6B illustrates the further embodiment of the control device in a second control mode;

FIG. 7 illustrates a second embodiment of a method of controlling a clutch;

8A-8F depict various signals and status indicators during execution of the first embodiment of the method;

detailed description of the embodiments

Fig. 1 schematically shows a powertrain in a vehicle for transmitting power from a power source 10, such as an internal combustion engine or an electric motor, to wheels 70 of the vehicle. The powertrain shown in fig. 1 includes a torque converter/lock-up clutch (TC/LUC) 20, a forward-neutral-reverse clutch (DNR), a transmission 40, fixed gears 50, and a differential 60.TC/LUC 20 couples the output shaft of power source 10 to DNR 30 at a controllable slip ratio and torque ratio (i.e., the ratio between the torque transmitted at its output and the torque received from power source 10 at its input). A DNR clutch 30 is provided to couple the TC/LUC 20 to the transmission 40. The DNR clutch 30 is controllable to assume one of a drive mode of operation D corresponding to driving the vehicle in a forward direction, a reverse mode of operation R in which the vehicle is driven in a reverse direction, and a neutral mode of operation in which it maintains the transmission 40 decoupled from the TC/LUC 20. The transmission 40 transmits the power delivered from the DNR clutch 30 to the wheels 70 via the fixed gear 50 and the differential 60 at a gear ratio selectable from a continuous range.

In the illustrated embodiment, the settings or operating modes of the torques TC/LUC 20, DNR 30, and the transmission 40 are determined by hydraulic signals (i.e., pressures of hydraulic fluid). The hydraulic signal is generated by a Hydraulic Control Unit (HCU) 80, and a supply flow P is supplied to the Hydraulic Control Unit (HCU) 80 by a pump 85 ₈₀ . In the illustrated embodiment, the TC/LUC 20 mode of operation is governed by hydraulic pressure P ₂₀ The operating mode of the DNR clutch 30 is controlled by the hydraulic pressure P ₃₂ And the operating mode of the transmission is controlled by the hydraulic pressure P ₄₁ And P ₄₂ To set. For this purpose, a hydraulic control unit 80 is provided, which hydraulic control unit 80 is in turn controlled by a Transmission Control Unit (TCU) 100. Alternatively, the operating modes of the various powertrain elements may be controlled by electrical signals, for example using electromagnetic actuating elements. The TCU 100 is further coupled to the engine control unit 90, for example via a bus (here CAN bus 95). The TCU is further configured to receive input signals from various inputs, such as a turbine speed signal (output speed of TC/LUC), a primary pulley speed corresponding to the DNR output speed, a secondary pulley speed at the output of the transmission 40, a secondary pulley pressure, and a tank temperature. Other input signals, e.g. from accelerator pedal, brake pedal (not shown) and sensorsInput signals to components, such as speed sensors, temperature sensors, torque sensors, etc. (not shown), may be received and monitored by the engine control unit 90 and communicated to the TCU 100 via the CAN bus 95.

Fig. 2 schematically shows a control arrangement 100 comprising a controller C for controlling a clutch CL in a transmission system _CL . Controller C _CL Configured as an open-loop controller and a closed-loop controller. The clutch CL can be controlled by a control signal P _set To be controlled to selectively assume one of a disconnect mode of operation, a controlled slip mode of operation and a lock mode of operation. In practice, there are hydraulic systems that convert a control signal, typically a low energy signal, into a signal capable of actuating a clutch (for example, into an electrical signal that actuates the clutch by electromagnetic force), or into a hydraulic pressure that causes a hydraulic actuator to actuate the clutch. In other embodiments, there may be an amplifier that amplifies the control signal and uses the amplified control signal to generate hydraulic pressure to actuate the clutch. These details will be omitted here in order not to distract from the essential features of the present controller. At present, it is only necessary that the clutch CL is coupled to the control signal P _set Responsive, and the response characteristics may vary over time due to wear of the clutch, and also depend on the operating temperature T of the clutch _CL In particular the working temperature of the hydraulic fluid present therein.

As shown in fig. 2, a controller C _CL Includes an open-loop controller OLC that determines a control signal component P for controlling the clutch CL based on the estimated clutch response characteristic _f . The response characteristic may be estimated based on specifications provided by the manufacturer and the prevailing temperature of the clutch. Open-loop controller OLC (i.e. controller C configured in an open-loop control configuration) _CL ) Includes a simulation module 124, the simulation module 124 is based on the input control signal S from the main controller 110 _OLC And indicating the actual temperature T of the clutch _CL Generates a control signal component Pf.

Controller C _CL Also included is a feedback controller CLC (i.e., configurable as a feedback controller) to be based onObserved response of clutch CL to provide a feedback control signal component P for controlling the clutch _c . In the illustrated embodiment, the observed response is slip rate ns as determined by slip detector 116. The feedback controller CLC further comprises a comparator 111 for comparing a desired response (e.g. a specified slip rate) with the observed response and providing an error signal indicative of the difference. The feedback controller CLC further comprises a control signal generator 112 for generating a feedback control signal component P based on the error signal e _c . The control signal generator 112 may, for example, include one or more of a proportional component, an integrator component, and a differentiator component.

Controller C _CL Further comprises a combination component 113 which may select a feedback control signal component Pc, an open-loop control signal component Pf or a combination thereof as the control signal P to be provided to the clutch depending on the control signal S113 from the main controller 110 _set . The combination of the control signal components Pc and Pf may for example be a (weighted) sum or product of these signal components.

In the illustrated embodiment, a main controller 110 is also provided to control the exchange of respective corresponding signals S ₁₀ 、S ₄₀ 、S ₃₀ Other driveline components T ₁₀ 、T ₄₀ 、T ₃₀ . Other driveline components may include, for example, the engine 10, as well as the transmission 40 and another clutch. For example, if clutch CL is DNR clutch 30, the other clutch to be controlled may be a lock-up clutch in the torque converter, and vice versa. The master controller 110 is responsible for proper coordination of the manner in which the various components of the transmission are controlled. For example, the main controller 110 may control the driveline such that the transmission always has the highest torque capacity, such that sudden torque changes, e.g., caused by bumps in the road, are absorbed by the clutches and slippage of the transmission is avoided.

Controller CCL has at least a first operating mode in which feedback controller CLC is enabled to generate control signal P maintaining clutch CL in a stable slip operating mode _c . Stable sliding operation dieFormula refers to a slip operating mode in which the clutch transmits at least substantially constant torque at an at least substantially constant slip rate. This may be the case, for example, for a situation where the input to the clutch rotates at a constant speed, while the output of the clutch does not rotate but a predetermined torque is applied (e.g., when a vehicle using the driveline is held stationary). In another example, the output of the clutch rotates, but at a lower rotational speed than the input, while a substantially constant torque is transmitted to maintain the vehicle at a constant speed or accelerate at a constant rate. It should be noted that minor variations are tolerable, for example no more than 20% variation in the torque transferred and slip ratio over a 20ms interval.

In case the feedback controller CLC maintains the clutch CL in a stable slipping mode of operation, the controller evaluates the control signal P by which this mode of operation is maintained _c Is measured. Control signal P _c May for example be a stable value of a control signal, such as an output provided by an integrator component of the control signal generator 112. The control signal may be considered to be sufficiently stable if the change in the control signal is less than a predetermined threshold (e.g., based on the estimated noise level) (e.g., a slip rate corresponding to zero slip or a predetermined minimum amount of slip). If no integrator component is present, it may be an average value. In an alternative embodiment, the control signal P may be based on an expectation, taking into account the time constant determined by the elements in the closed loop _c The stable estimated final value is used to estimate the representative value before stabilization. For example, the value of the control signal may be evaluated upon expiration of a predetermined time interval (e.g., a time interval having a duration of 2 or 3 times the time constant). Although the feedback component may still show variations over the noise level, the estimate at this point in time may be used to estimate the value at which the control signal will settle. Controller evaluates transmission fluid temperature T in clutch _CL A second representative value of (a). Typically, the transmission fluid temperature T _CL Will rise during this mode of operation due to energy dissipation in the clutch. Transmission fluid temperature T _CL The first control at the controllerThe average value during the mode may be, for example, a representative value. Alternatively, the representative value may be the transmission fluid temperature T _CL The value halfway through the first control mode, or may be corrected for changes due to energy dissipation based on a measurement of transmission fluid temperature at another point in time.

Controller C _CL Further has a second control mode in which the feedback controller CLC is disabled and the open-loop controller OLC generates a control signal P maintaining the clutch in the locked operating mode _f Wherein the control signal is dependent on at least the evaluated first and second representative values. This functionality is schematically indicated by the updating module 120 for updating the simulation module 124 based on the evaluated representative value.

The open-loop control signal generator 124 may, for example, include a predicted signal generator component that generates a predicted component based on specifications provided by the manufacturer of the clutch and a simulation module that provides an adaptation of the predicted component based on input from the update module 120.

The first embodiment is described in more detail with reference to fig. 3A and 3B. In the embodiment shown in fig. 3A, clutch CL is DNR clutch 30. In the illustrated embodiment, clutch CL is illustrated as a unit that further includes a hydraulic actuation system that is responsive to control signal P _set To actuate clutch 30. In the illustrated embodiment, the open-loop control signal generator 124 is schematically illustrated as providing the predicted signal component P _Kp . Which may receive a predicted signal component P from an external source as shown in the figure _Kp Or the signal is generated internally. In this example, the signal P _Kp Specifying control signal P _set Expected value of the control signal P _set The DNR clutch is caused to operate at its kiss point and at the reference temperature in the new state of the clutch. When operating at its kiss point, the DNR clutch transmits a low torque, different from 0, that nevertheless facilitates acceleration from a stationary condition of the vehicle. The torque transmitted in this operating mode of the clutch may be, for example, in the range of 1 to 10 Nm. However, the control signalDepends on the temperature of the clutch (indicated as T) _oil ) And this dependency will also change during the life of the clutch 30. The open-loop control signal generator 124 further comprises a simulation module 126 to adapt the prediction signal P _Kp In order to obtain an open-loop control signal component P _Kp,adp . The update module 120 periodically adapts the characteristics of the simulation module 126 to account for changes in the dependencies. The simulation module 126 may, for example, comprise a look-up table specifying the adaptation signal P for each temperature range _adp The value of (c). Each temperature range may be, for example, a fixed range of 1-10 degrees, such as from 0 to 10, from 10 to 20, and so forth. Alternatively, the temperature ranges may have different sizes, for example, a larger size temperature range may be used where the response of the clutch is less dependent on temperature. In another embodiment, P _adp Is expressed as a temperature value T _oil Wherein the parameters of the function (e.g., splines) are adapted to satisfy the observed characteristic.

One method of operation is now described in more detail with reference to fig. 4 and 5A-5E, as well as fig. 3A, 3B. Wherein fig. 4 schematically illustrates the steps of the method, and fig. 5A-5E illustrate signals occurring in the controlled drive train as follows:

fig. 5A shows a binary signal that specifies whether a calibration procedure can be initiated (true/false).

Fig. 5B shows the (physical) operating mode of the DNR clutch.

FIG. 5C shows a feedback control signal component, here an integrator component P from a PID controller _I 。

FIG. 5D shows the contribution P from the simulation module 126 _adp 。

FIG. 5E shows the temperature T of the hydraulic transmission fluid in the clutch 30 _oil 。

Returning now to FIG. 4, there is shown a verification step S0 in which it is verified whether the appropriate conditions are in force to perform a calibration procedure, i.e., a procedure in which the simulation module 126 or simulation model used to control the clutch is updated. In this step, it is possible, for exampleVerifying that the main controller 110 has controlled the transmission in the idle-neutral state. In this state, the vehicle is in a stationary state, in which the output shaft of the DNR clutch 30 is in a non-rotating state, while the input shaft of the DNR clutch 30 is driven by the engine at a non-zero rotational speed and the engine 10 is in a stationary operating state. As can be seen in FIGS. 5A, 5B, this condition is at time t ₀ None (not yet) is satisfied because the DNR clutch 30 is in its off mode of operation. Additionally, it may be verified whether a predetermined distance has been traveled since a previous execution of the method. Alternatively, if an abnormal condition in the drive train is detected, the request may be denied. In other embodiments, the method may be performed in a stationary state at a time, regardless of the distance traveled. At a point in time t ₁ Here, the DNR clutch is set to the slip operation mode with the vehicle in a stationary state, so the rotation speed of the output shaft of the DNR clutch is still 0. In the idle-neutral mode of operation, the main controller 110 is configured to maintain the clutches in the TCLUC assembly in a fully disengaged mode of operation. In this mode of operation, the torque converter in the TCLUC assembly provides only a weak mechanical coupling.

At the time point t ₁ Here, it is confirmed that the required condition is satisfied in step S0, and the feedback controller CLC is enabled to generate the control signal P in step S1 _c The control signal P _c The clutch 30 is maintained in a stable slip operating mode in which a specified minimum amount of torque (e.g., in the range of 1 to 10 Nm) is transferred to the output of the DNR clutch 30. The control mode of the controller in this step is schematically shown in fig. 3B. In the example shown, the feedback controller CLC provides only a correction to the predicted value, which is the output signal P required to achieve maintenance of the clutch in this operating mode _set As necessary. In other embodiments, the open loop component 124 as shown in FIG. 3B may also provide an adaptation component P _adp And in this case the feedback controller CLC provides a correction signal P _c To correct the signal P _Kp,adp To achieve the kissing point, as shown in figure 5C. After a predetermined time interval, at a point in time t2, the signal P is corrected _c Is stable and has a representative value of C _I Is estimated in step S2. Also confirm that is denoted as T _oil * Is a representative value of the temperature of the hydraulic transmission fluid. This may be at time interval t ₂ -t ₃ In order to determine an average value of the feedback control signal component and an average value of the temperature.

In step S3, the update module 120 updates the simulation module 126. For example by using a representative value C derived from the correction signal _I The determined new lookup table value is updated with the determined representative temperature T _oil * Signal P of the temperature range of interest _adp The look-up table value of (2). For example, if the representative value T of the temperature _oil * At 73 degrees celsius, the lookup table values for the range that includes the interval are updated. The previous value in the look-up table may be replaced by a representative value of the control signal, for example, but alternatively it may be replaced by an alternative value which is a linear combination of the previous value and the representative value. Alternatively, if the simulation module 126 calculates its output signal as a parametric function of the actual value of the temperature, the update module 120 may update the simulation module 126 by modifying the functional parameters.

S4 in fig. 4 is a waiting step in which a change in the operation mode of the clutch from slipping to open or slipping to close is monitored.

If one of these operating mode changes is at the point in time t ₄ Is detected, the clutch 30 is controlled by the open loop controller OLC using the updated simulation module 120.

Fig. 6A shows a second embodiment in which the clutch to be controlled is a lock-up clutch of a torque converter lock-up clutch unit. As in the embodiment of fig. 3A, clutch CL is illustrated as a unit further including a hydraulic actuation system responsive to control signal P _set To actuate the clutch 20. Alternatively, another actuation system (such as an electromechanical actuation system) may be used. As in the embodiment of FIG. 3A, the operation of the clutch 20 is dependent upon its operating temperature. As a further complication, a torque M to be transmitted is required _luc Should be controllable. In the embodiment shown, the open-loop controller OLC comprises a prediction signal generator PRD,the prediction signal generator PRD generates the prediction signal P, for example, based on manufacturer specifications for a new product when operating at a reference temperature _f . The prediction signal generator PRD uses an input signal M, for example, provided by the main controller 110 _ref And n _s,ref Generating a prediction signal P _f . Generated prediction signal P _f Instructing the clutch 20 to assume a condition according to these specifications in which the clutch 20 can be caused to slip at a slip rate n _s,ref Transmitting torque M _ref Of the operating mode of (c). The simulation module 126 generates a simulation signal P _adp The simulation signal P _adp Will predict the signal P _f Adapted to obtain a transmitted torque M as a function of the clutch _luc And the actual prevailing temperature T _luc Control signal P of _set . The simulation module 126 may, for example, include a look-up table that specifies the adaptation signal P for each combination of temperature range and torque range _adp The value of (c). Each temperature range may be, for example, a fixed range of 1-10 degrees, such as from 0 to 10, from 10 to 20, and so forth. Alternatively, the temperature ranges may have different sizes, for example, a larger size temperature range may be used where the response of the clutch is less dependent on temperature. Likewise, the torque ranges used may be of the same magnitude as one another or may be of different magnitudes, depending on the degree of torque transmitted, depending on the adaptation signal required. In another embodiment, P _adp Is expressed as a temperature value T _oil And the torque M transmitted _luc Wherein the parameters of the function (e.g., splines) are adapted to satisfy the observed characteristic.

The method of operation in this embodiment will now be described in more detail with reference to fig. 7 and 8A-8F and fig. 6A, 6B. Wherein fig. 7 schematically illustrates the steps of the method, and fig. 8A-8F illustrate signals occurring in the controlled drive train as follows:

fig. 8A shows a binary signal that specifies whether a calibration procedure can be initiated (true/false).

Fig. 8B shows the (physical) operating mode of the lock-up clutch.

Figure 8C shows the feedback control signal component,here the integrator component P from the PID controller _I 。

FIG. 8D shows the contribution P from the simulation module 126 _adp 。

Fig. 8E shows the torque transmitted by the clutch.

FIG. 8F shows the temperature T of the hydraulic transmission fluid in the clutch 30 _luc 。

Returning now to fig. 7, there is shown a verification step S10 in which it is verified whether the appropriate conditions in force exist to perform the calibration procedure in S10. In this step, it may be verified, for example, that the transmission system is operating under steady state driving conditions, such that the clutch 20 transmits at least a substantially constant torque at a substantially constant rotational speed. This is the case, for example, if the vehicle is driving in a cruise control driving mode. This procedure may also be performed if the vehicle is in a constant moderate acceleration driving mode, while maintaining the transmitted torque at a substantially constant level. This procedure can be successfully completed as long as the variations in the transmitted torque and rotational speed remain within predetermined limits (e.g., no more than 20% deviation from their average). Alternatively, the procedure can be started without a prerequisite, but this has the following disadvantages: the risk of unsuccessful procedures is high. In addition, it may be verified whether a predetermined distance has been traveled or a predetermined time period has elapsed since a previous execution of the method. Alternatively, if an abnormal condition in the driveline is detected, the request may be denied. As shown in fig. 8A, at a time point t ₁₀ The condition has not been met because the transmitted torque is detected to show a change that exceeds a predetermined limit.

At t ₁₁ In the subsequent step S11A, S B of the initiation, the ramp down control signal P _ramp Is provided to cause the operation of the clutch 20 to gradually transition from the locked operating mode to a slip operating mode in which the LUC transmits a predetermined value of torque and a predetermined amount of slip. This is schematically illustrated in fig. 6B. In this mode of operation, the difference between the input rotation speed and the output rotation speed is maintained at a constant value, for example a value in the range of 10 to 100rpm, for example around 30 rpm.

Once this condition is detected, feedback control is enabled in step S12 to generate a control signal to maintain the clutch in a stable slip operating mode. In an exemplary embodiment, if the control signal component p is fed back within a predetermined time interval _c Is less than the threshold value, the operation of the clutch 20 is deemed stable in the designated slip operating mode. For example, a feedback control signal component p may be required _c Is less than 20% of the average value over a specified time interval (e.g., a 20ms interval). In this example, at a point in time t ₁₄ Where a feedback control signal component p is detected _c Here, pi is kept within specified boundaries during a specified time window. Assuming a PID or PI controller is used as the feedback control signal generator 112, the feedback signal component will be equal to that from the integrator component p _I Of the signal of (1).

In an embodiment, step S12 may immediately follow step S10 if it is determined that the conditions set in S10 are complied with. However, this may involve a risk of an appreciable and audible transition of the clutch 20 from its locked operating mode to its slipping operating mode, which leads to reduced driving comfort. In an alternative embodiment, the transition between step S10 and step S12 may be provided by: in this phase, the feedback controller is immediately enabled, but the slip ratio n _s,ref Gradually increasing from zero slip to a steady slip operating mode.

Once at the time point t ₁₄ Where it is determined that the feedback control signal is stable, in step S13, for the control signal p _c Evaluation of the representative value c _I . In practice, this may be, for example, at the point in time t ₁₄ The determined output of the integrator component in the control signal generator 112. Also for the temperature T of the clutch 20 _luc Evaluation of the representative value T _luc * E.g. temperature T of hydraulic fluid used therein _oil Representative values of (a). Typically, the transmission fluid temperature T _oil Will rise during this mode of operation of the clutch due to energy dissipation in the clutch. Transmission fluid temperature T _CL At the controllerThe average value during the first control mode may be, for example, a representative value. Alternatively, the representative value may be the transmission fluid temperature T _CL T in which stable operation is determined ₁₄ The value halfway through the previous time window, or the measurement may be corrected for changes due to energy dissipation based on the measurement of the transmission fluid temperature at another point in time. Further, for the point at t ₁₄ Evaluating the representative value M for the torque transmitted in a steady slip operating mode maintained within a previously specified time window _luc *。

Representative value c _I 、T _luc * And M _luc * Is used in step S14 to determine updated settings for the simulation module 126. To this end, the update module 120 may identify an entry in a lookup table maintained in the simulation module 126 corresponding to the respective representative values T of the clutch temperature and the transmitted torque _luc * And M _luc * And using the representative value c of the feedback control signal component _I To replace the value of the entry. Alternatively, the update module 120 may replace the old value in the entry with a value determined as a weighted average of the old value and the representative value. It is noted that if an entry in the lookup table maintained in the simulation module 126 has a value containing the representative value T _luc * And M _luc * And boundary values of the transmitted torque, the entry corresponds to these representative values. In which the signal component P is adapted _adp Is calculated as the transmitted torque value M _luc And a temperature value T _luc In a further embodiment of the parameter function of (3), the updating module 120 may adapt the parameters of the function to adapt the signal component P _adp And the representative value c of the feedback control signal _I And correspondingly.

In the illustrated embodiment, updates to the settings of the emulation module 126 are not immediately applied. Instead, in step S15, at a point of time t ₁₅ At this point, the clutch returns to its locked mode of operation in its old setting. Instead, the update is postponed until at point in time t ₁₆ The clutch enters a disconnect mode of operation. At this point in time, the new settings are applied in step S16. Changes in settings will not be madeThe driver perceives.

It should be noted that the illustrative embodiments may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Although specific functions may be performed by respective dedicated functional elements as an example, various functions may alternatively be performed by the same element at different points in time. Example embodiments may be implemented using a computer program product, such as a computer program tangibly embodied in an information carrier (e.g., in a machine-readable medium) for execution by, or to control the operation of, data processing apparatus (e.g., a programmable processor, a computer, or multiple computers). In an example embodiment, the machine-readable medium may be a non-transitory machine storage medium or a computer-readable storage medium.

Claims

1. A control device (100) for controlling a Clutch (CL) in a transmission system, which clutch can be passed a control signal (P) _set ) To be controlled to selectively assume one of a disconnect mode of operation, a controlled slip mode of operation and a lock mode of operation, the control arrangement comprising an Open Loop Controller (OLC) having a simulation module (126) and an update module (120) for updating the simulation module, the control arrangement further comprising a feedback controller (CLC) to provide a feedback control signal component (P) based on an observed response of the clutch _c ) The control device has at least a first control mode and a second control mode; wherein in the first control mode the feedback controller is caused to be able to generate a feedback control signal according to predetermined specifications, the feedback control signal maintaining the clutch in a stable slip operating mode, in the first control mode the controller evaluating a representative feedback signal value (c) of the feedback control signal _I ) And one or more respective representative state values of the one or more clutch state signals;

wherein the control means updates the simulation module using the representative feedback signal value and the one or more respective representative state values,

wherein in the second control mode, the feedback controller is disabled and the open-loop controller generates a control signal that maintains the clutch in the locked mode of operation, the control signal having a value that depends on an emulated signal value of an emulated signal generated by the updated emulation module, the emulated signal value depending on an actual value of the one or more clutch status signals.

2. The control apparatus of claim 1, wherein the feedback controller includes an integral action control component (112), and the representative feedback signal value is determined using the integral action control component.

3. A control arrangement in accordance with claim 1, wherein said simulation module (126) is updated in said first control mode to reduce a difference between said simulated signal value and a characteristic feedback control signal value associated with said one or more respective representative state values by said simulation module.

4. A control arrangement according to claim 3, characterised in that said difference is partly reduced.

5. Control arrangement according to one of the preceding claims, characterized in that the one or more clutch status signals comprise a temperature signal (T) indicating the operating temperature of the clutch _luc ，T _oil ) And in its first control mode, the controller determines a representative temperature value of the temperature signal, and the control device further uses the representative feedback signal value (c) _I ) And the representative temperature value (T) _oil * ) To update the simulation module (126).

6. The control arrangement according to claim 5, characterized in that the clutch is a clutch (30) in a forward-neutral-reverse DNR assembly, and the feedback controller is configured to maintain an operating mode in which the clutch transmits at least substantially constant torque at an at least substantially constant slip rate as a stable slip operating mode, wherein the output rotational speed of the clutch is equal to zero.

7. The control device of claim 5, wherein the one or more clutch state signals further include a torque signal (M) indicative of torque transmitted by the clutch (20) _luc ) And the controller in its first control mode determines a representative torque value (M) of the torque signal _luc * ) (ii) a Wherein said control means uses said representative feedback signal value (c) _I ) The representative temperature value (T) _luc * ) And the representative torque value (M) _luc * ) To update the simulation module (126).

8. The control arrangement according to claim 7, characterized in that the Clutch (CL) is a lock-up clutch (20) and the feedback controller is configured to maintain as the stable slip operation mode an operation mode in which the lock-up clutch transmits at least substantially constant torque at an at least substantially constant slip ratio, the control arrangement being configured to evaluate a representative torque value (M) indicative of the at least substantially constant torque in the stable slip operation mode _luc *)。

9. The control device of claim 8, wherein the control device is configured to cause the open-loop controller to gradually change the operating mode of the clutch in its locked operating mode to a slipping operating mode, and subsequently enable the feedback controller to maintain the clutch in the stable slipping operating mode.

10. A powertrain in a continuously variable transmission system comprising a torque converter/lock-up clutch (TC/LUC) (20), a forward-neutral-reverse DNR clutch (30) and a transmission (40), the powertrain further comprising a control device for controlling the DNR clutch (30) according to one of claims 1 to 6 and/or a control device for controlling the lock-up clutch (20) according to one of claims 1-5 and 7-9.

11. A method for controlling a clutch in a transmission system, the clutch being controllable by a control signal to selectively assume one of a disconnect mode of operation, a controlled slip mode of operation, and a lock mode of operation, the method comprising:

generating, by a feedback controller, a feedback control signal based on an observed response of the clutch in a closed-loop control mode, the feedback control signal maintaining the clutch in a stable slip operating mode;

evaluating a representative control signal value of the feedback control signal by which the clutch is maintained in the steady slip operating mode, and one or more respective representative state values of one or more clutch state signals indicative of a state of the clutch;

updating a simulation model indicative of the estimated response characteristic of the clutch based on the evaluated representative control signal value and the one or more respective representative state values;

12. The method of claim 11, wherein an integrating action is used in the closed-loop control mode, and the representative control signal value is determined using the integrating action.

13. The method of claim 11 or 12, wherein the clutch is a forward-neutral-reverse DNR clutch and the feedback controller is configured to maintain an operating mode in which the clutch transmits at least substantially constant torque at an at least substantially constant slip rate as the stable slip operating mode, wherein an output rotational speed of the clutch is equal to zero, wherein the one or more clutch state signals comprise a temperature signal indicative of an operating temperature of the clutch, and the evaluating comprises evaluating a representative temperature value of the temperature signal; wherein the updating comprises updating the simulation model using the representative control signal value and the representative temperature value, and the updated simulation model is used to generate an open loop control signal as a function of an actual value of the temperature signal to maintain the clutch in its locked mode of operation.

14. The method of claim 11 or 12, wherein the clutch is a lock-up clutch and the steady slip operating mode is an operating mode in which the lock-up clutch transmits at least substantially constant torque at an at least substantially constant slip rate,

and the evaluating includes evaluating a representative temperature value of the temperature signal indicative of the operating temperature of the lock-up clutch, and also evaluating a representative torque value indicative of the at least substantially constant torque;

wherein the updating comprises updating the simulation model using the representative feedback signal value, the representative temperature value, and the representative torque value;

and the updated simulation model is used to generate an open loop control signal as a function of the actual value of the temperature signal and the actual value of the torque.

15. The method of claim 11 further comprising an open loop control mode preceding the closed loop control mode to gradually change the operating mode of the clutch from its locked mode to a slipping operating mode and then enable a feedback control assembly to maintain the stable slipping operating mode.

16. The method of claim 11, wherein the open-loop control signal for maintaining the clutch in the locked mode of operation depends on the evaluated representative value in a delayed manner in which adaptation of the simulation model is postponed until the clutch has assumed an off mode of operation.