DE10235432B4 - Method for carrying out a diagnosis of an operating state of an electromagnetic drive system - Google Patents

Abstract

Method for carrying out a diagnosis of an operating state of an electromagnetic drive system (1), in particular an electric actuator, with a coil and an armature which can be longitudinally movably actuated via a magnetic field of the coil, an actual value (i_act) of a coil current, a theoretical value (i_theo) of a coil current Coil current and a coil current difference (i_res) between the actual value (i_ist) and the theoretical value (i_theo) are determined, characterized in that
- Changes in the theoretical value (i_theo), which occur for example as a result of a mutual induction (L_g) in the electric actuator, a detector (3) are supplied and / or
- Changes in the theoretical value (i_theo), which are caused in particular by temperature influences, be compensated by means of an observer controller (8).

Description

The The invention relates to a method for carrying out a diagnosis of a Operating state of an electromagnetic drive system according to the im Preamble of claim 1 further defined type.

Out In practice, electromagnetic drive systems such as designed as proportional pressure control valves electro-hydraulic Actuators known by means of which from a generated electrical Electricity proportional hydraulic pressure to hydraulic Consumer is adjustable. Such proportional pressure control valves are with a coil and a over a magnetic field of the coil longitudinally movably actuated Anchor formed, the method in the same way for electromechanical Actuators is applicable.

Becomes applied to the coil, a voltage is formed in the iron circle of Coil out a magnetic flux, which is about the anchor and one formed between the coil and the anchor Working air gap closes. An armature force in the axial direction acts on the armature, in the case of proportional solenoids, they are largely proportional to the adjacent ones Excitation current and independent from the anchor position. Due to the position of the anchor is the Size of the variable Aperture cross-section, which is the gap between valve seat and anchor corresponds and forms the connection to the tank, varies and thus the flow rate of hydraulic oil set.

Battery powered as well as electromechanical actuators are used to control automatic transmissions as an interface between an electrical signal circuit and a hydraulic circuit used by electro-hydraulic systems. It is usually for each gear to be switched to the forward drive and reverse a clutch or brake unit provided, which is usually hydraulic is pressed.

to Realization of the gear change has an electrohydraulic system an automatic transmission now the task, depending on a driving condition and a specification of a driver, the clutches and brakes of the automatic transmission to control the requirements accordingly, so that a desired Gear is engaged.

at increase in hydraulic components used in automotive engineering the requirements regarding the dirt oil resistance constantly These requirements arise from increasing transmission times and longer and longer expectant oil change cycles up to the omission of the oil change result. With increasing contamination of the hydraulic oil occurs in electromagnetic actuators a so-called Hystereseverbreiterung as well as a so-called "stick-slip" behavior up to to a valve terminals. From these malfunctions of the actuators results in a poor shifting comfort, resulting in a transition into an emergency program can.

Around such malfunctions to diagnose or an anchor terminals before a total failure of a To detect electromagnetic actuator can be method proposed by means of which errors in the electrical and in the Mechanics can be detected.

One such method for model-based Error detection on electromagnetic proportional valves with Microcontrollers, for example, in the German magazine "O + P, oil hydraulics and pneumatics ", 44 (born 2000), no. 7, pages 449-453. In this The method becomes an armature stroke of a proportional pressure control valve estimated by measuring current and voltage, and then it becomes carried out an error analysis. It generates many features that are used to Errors in the electrical system and in the mechanics to recognize.

such Methods have the disadvantage that measurements and the time follow it Evaluations or diagnoses due to their complexity not feasible in real time are. Furthermore, to carry out such a method due to the complex diagnosis a very high storage use as well as a high computing power required in the field of Vehicle control technology usually used not provide.

• – ein Schließsignal ermittelt wird, das von einem Soll-Bremsdruck abhängig ist,
• – ein Schließimpuls aus dem Vergleich eines aktuellen Soll-Bremsdruckes mit einem zeitlich zurückliegenden Wert des Soll-Bremsdruckes ermittelt wird,
• – ein Stellsignal aus einem Vergleich des Soll-Bremsdruckes mit einem Ist-Bremsdruckes ermittelt wird und
• – ein Dämpfungssignal aus einer Bewegungsgeschwindigkeit eines Aktuators des Ventils ermittelt wird.

From the DE 100 21 436 A1 a method for determining a manipulated variable of a valve in a vehicle brake system is known, in whose context

• A closing signal is determined, which is dependent on a desired brake pressure,
• A closing pulse is determined from the comparison of a current setpoint brake pressure with a value of the setpoint brake pressure which is past in time,
• - An actuating signal from a comparison of the desired brake pressure with an actual brake pressure is determined and
• - A damping signal from a movement speed of an actuator of the valve is determined.

berechnet wird. Hierbei wird der verkettete magnetische Fluß als Funktion der Zeit und daraus die Änderung des verketteten magnetischen Flusses als Funktion des Stroms berechnet, wobei die Funktion des verketteten magentischen Flusses als einen allmählich verlaufenden Anteil die differentielle Induktivität L_d(i) der Spule enthält, und die differentielle Induktivität L_d(i) aus der Funktion mit Hilfe eines Integrationsverfahrens abgetrennt wird.From the DE 100 34 830 A1 a method is known in which an armature movement of an electromagnetic actuator with at least one coil by means of the equation

is calculated. Here, the concatenated magnetic flux is calculated as a function of time and therefrom the change of the concatenated magnetic flux as a function of the current, wherein the function of the concatenated magentic flux contains as a gradual portion the differential inductance L _d (i) of the coil, and differential inductance L _d (i) is separated from the function by means of an integration method.

The DE 100 62 107 C1 discloses an actuator control for an electromagnetic actuator including, inter alia, two three-position controller for controlling the field currents in two solenoids. The task variable of the two three-position controllers is in each case the difference between a respective desired field current and a sum, weighted by control parameters, from a measured coil current and a coil current calculated by an observer.

The DE 199 10 497 A1 discloses a method for the position measurement of a magnetic tank mounted in a magnetic tank, wherein it is proposed, the differential inductance (L _D ) by measuring the time course of the coil current (i) according to L D = Δt / Δi (u - R · i) to determine and from this after prior calibration of the armature position as a function of the differential inductance (L _D ) to determine the respective armature position.

ermittelt, wobei für L_i(i) als Modellvorstellung ein gerades Polynom 6-ter Ordnung angenommen wird, dessen Koeffizienten über einen Least Square Schätzer aus einer Datenmatrix des magnetischen Flusses ψ bestimmt wird. Der magnetische Fluss ψ und ∂ψ/∂i werden dabei aus einer gemessenen Ankerspannung u und einem sich aufbauenden Stromverlauf i ermittelt.From ISERMANN, R., among others: Model-based error detection on electromagnetic actuators. In: Progress, Reports VDI, Series 8, No. 743, pp 58-80 it is known to estimate an armature stroke of an electromagnetic actuator from a current and voltage measurement. For this purpose, the armature stroke on the equation

determined, where for L _i (i) is assumed as a model idea a straight polynomial of 6th order whose coefficient is determined by a least square estimator from a data matrix of the magnetic flux ψ. The magnetic flux ψ and ∂ψ / ∂i are determined from a measured armature voltage u and a build-up current curve i.

Of the The present invention is therefore based on the object, a method for detecting mechanical malfunctions of electromagnetic Drive systems available which has a low resource requirement and feasible in real time is.

According to the invention this Task with a method according to the features of claim 1.

By the adaptation of a theoretically determined resistance value of Coil of an electromagnetic drive system is achieved that a course the actual value of the coil current almost identical to a Model is modeled in real time, and deviations of the actual value of the coil current from the theoretically determined value of the coil current advantageously for the diagnosis of malfunctions of the electromagnetic Drive system can be used. In particular mechanical Dysfunctions such as jamming or tearing an anchor in one Valve or even an elevated one Friction during an armature movement in a valve can occur in be diagnosed advantageously.

When using an electromagnetic drive system in an automatic transmission in connection tion with the method according to the invention, the shift quality is significantly improved. This is achieved in that with the adaptation of the theoretical resistance value of the coil and the high accuracy of the simulation of the course of the actual value of the coil current an exact control, for example by an optimized on the respective coil resistance current control, the switching elements is possible.

If a maximum voltage on the electromagnetic drive system or rests against the coil, there is a risk of a critical Coil internal temperature, which leads to destruction of the windings of the coil to lead can exceed. Such coil internal temperatures result inter alia from a greatly increased Coil current associated with a high ambient temperature the electromagnetic drive system, the electrohydraulic in an electrohydraulic Control system of an automatic transmission essentially from the temperature of the hydraulic oil affected becomes.

With Help of the method according to the invention, in which the theoretical Resistance value of the coil by means of adaption in dependence of the currently present operating state exactly determined can be, in a simple way, from the adapted theoretical Resistance value of the coil, the coil internal temperature can be determined and thus the availability of the electromagnetic drive system can be increased.

Furthermore let yourself from the knowledge of the supplied electric power and the coil inside temperature the oil temperature determine, since a thermal equilibrium is established.

One Emergency program, which protects the electromagnetic drive system is provided and over the one operation of the electromagnetic drive system from a critical inside coil temperature prevented is thus only started to actual damage to avoid. A well-known from practice as prophylactic Starting an emergency program when a hydraulic oil temperature is detected, which could cause a critical coil internal temperature, wherein an electromagnetic drive system disadvantageously already deactivated before reaching a critical coil internal temperature can be avoided here. Due to the exact knowledge the coil internal temperature becomes the availability of the actuators elevated, that these can be operated to their thermal design limits.

Furthermore is advantageous that electromagnetic Drive systems whose operating conditions with the inventive method be easily diagnosed, even in hard-to-reach Positions of an automatic transmission can be arranged, d. H. directly into the gearbox can be implemented because a cause of error can be pinpointed and an exchange be carried out targeted by defective components and thus cost-saving can. This means that the Expansion of an electromagnetic drive system using the inventive method must be done only with knowledge of a really given defect.

Further Advantages and developments of the invention will become apparent from the dependent claims and from the principle described below with reference to the drawing Embodiment.

In The drawings are several block diagrams of a method for execution a diagnosis of an operating state of an electromagnetic Drive system as well as several current-time diagrams, which will be explained in more detail in the following description.

It shows:

1 a highly simplified block diagram of an electromagnetic drive system for performing a diagnosis of an operating state of the electromagnetic drive system;

2 a block diagram of a computer unit with its input and output variables;

3 a block diagram of a part of a detector;

4 a block diagram of another part of the detector according to 3 ;

5a and 5b a course of a coil current over time in a normal armature movement and a corresponding course of a difference between an actual value and a theoretically determined value of a coil current;

6a and 6b a course of a coil current over time in a mechanical anchor terminals and a subsequent tearing of the armature and a corresponding course of a difference between an actual value and a theoretically determined value of a coil current;

7a and 7b a course of the coil current over time at a mechanical anchor terminals and a corresponding course of a difference between an actual value and a theoretically determined value of a coil current and

8th a block diagram of an electromagnetic drive system with an adaptation of a coil resistance and a dependent of the adapted coil resistance current control of the coil current.

The 1 shows a highly simplified block diagram of an electromagnetic drive system 1 to which a voltage u_act is applied. In this case, an actual value of a coil current i_act flows through a coil, not shown, of the electromagnetic drive system designed as a proportional pressure control valve 1 ,

Parallel to the real electromagnetic drive system 1 is a computer unit 2 switched, via which on the basis of the real electromagnetic drive system 1 applied voltage u_ist a theoretical value i_theo of the coil current is calculated. The theoretical value i_theo of the coil current is calculated using a linear model. When calculating the theoretical value i_theo of the coil current, in contrast to the real system of the electromagnetic drive system 1 Movements of an armature in the interior of the coil, which cause disturbances in the course of the actual value i_act of the coil current through a mutual induction L_g generated by the armature movement, are initially not taken into account, as a result of which the normal behavior is reproduced exactly.

Both systems, ie the real drive system 1 and the linear model, as a function of the voltage u_act, determine the coil current i_ist or i_theo, the detected current strengths differing in such a way that the measured actual value i_act of the electromagnetic drive system 1 the mutual induction L_g as a disturbance affects its course.

At the Comparison of the two currents or in the comparison between the actual value i_act of the coil current and the theoretical value i_theo of the coil current thus occurs Difference or Residual i_res on, by the by the mutual induction disturbed Power buildup is caused in the real system, with this deviation the armature movement is clearly assigned.

berechnet. Dabei setzt sich die Spannung u aus der am Widerstand der Spule abfallenden Spannung, die sich aus dem Produkt des Widerstandes R_sp(T) und der Stromstärke i_theo ergibt, der induzierten Spannung, die sich aus zeitlicher Änderung des magnetischen Flusses ergibt, und der geschwindigkeitsabhängigen Störgröße z, die in Abhängigkeit der Ankergeschwindigkeit steht, zusammen. In der Systemgleichung des elektrischen Teilsystems sind nur die sehr vereinfachten partiellen Ableitungen nach der Stromstärke I und der Ankerposition x dargestellt. Die Ableitung des magnetischen Flusses nach der Stromstärke ist hierbei durch eine konstante Induktivität L ersetzt, die für die jeweils eingesetzten Komponenten des elektromagnetischen Antriebssystems bekannt ist. Die partielle Ableitung nach der Ankerposition wird zusammen mit der Geschwindigkeit als geschwindigkeitsabhängige Störgröße interpretiert, welche hier die induzierte Spannung aufgrund der Gegeninduktion L_g darstellt.In the computer unit 2 is the system equation of the electrical subsystem a voltage u according to the formula

calculated. In this case, the voltage u is made up of the voltage drop across the resistor of the coil, which results from the product of the resistor R_sp (T) and the current i_theo, the induced voltage which results from temporal change of the magnetic flux, and the speed-dependent disturbance z, which is dependent on the anchor speed together. In the system equation of the electrical subsystem, only the very simplified partial derivatives according to the current intensity I and the armature position x are shown. The derivation of the magnetic flux according to the current strength is replaced by a constant inductance L, which is known for the particular components of the electromagnetic drive system used. The partial derivative according to the anchor position is interpreted together with the velocity as a velocity-dependent disturbance, which here represents the induced stress due to the mutual induction L_g.

at the method shown for performing a diagnosis of Operating state of an electromagnetic drive system the physical relationships evaluated. Ohm's law describes a linear relationship between the voltage u and the current i. From the ratio of Voltage u to the current i is for an initial value of the resistance determination a rough estimate of the current value of the resistance derivable. In addition, the resistance R of the coil depends on the temperature, and there is also a linear relationship between the resistance the coil and the temperature of the coil.

This results in a temperature-dependent value R_sp (T) of the coil resistance according to the formula R_sp (T) = R_sp_0 * (1 + α * (T_sp-T_sp_0)) with R_sp_0 as a known reference resistance at the reference temperature T_sp_0. With α the temperature coefficient of electrical resistance is included in the calculation approach, this represents the ratio of the relative change of the resistance in relation to the temperature change.

The residual i_res is used to diagnose the operating state of the real electromagnetic drive system 1 and also the adaptation or adaptation of the linear model to the real electromagnetic drive system 1 carried out.

2 provides a block diagram of the computer unit 2 , wherein the various input and output variables are specified. In particular, the coil temperature T_sp is determined from the theoretically determined resistance value R_sp of the coil, and the resistance value R_sp is forwarded to a diagnostic module (not shown).

In 3 is a block diagram of a detector 3 the computer unit 2 represented, by means of which on the basis of the actual value i_ist the coil current, the actual value u_ist the coil voltage and a voltage of a current source u_bat the residual i_res the coil current, the theoretical value i_theo of the coil current and the resistance value R_sp the coil is determined.

By the applied voltage u_bat the voltage source or a vehicle electrical system voltage of a motor vehicle and the duty u_ist, which with a filter 4 is filtered, the effective voltage u_theo is calculated for the linear model.

After the determination of the theoretical voltage u_theo is in a function block 5 a comparison of the theoretical value u_theo carried out over an empirically determined map. The resulting value of the voltage u_anp is used to determine the theoretical value i_theo of the coil current, the theoretical value i_theo of the coil voltage being determined via the system equation of the electrical subsystem, which in the block diagram in accordance with FIG 3 in which by the reference numeral 6 designated area is shown graphically.

The theoretical value i_theo of the coil current is in the function block 7 of the block diagram is compared with the actual value i_act of the coil current, and at the same time the residual i_res is determined, which is an output value of the detector 3 represents. Furthermore, the residual i_res becomes a switch 8th supplied as input signal. The desk 8th is switched in response to a predetermined threshold, which may preferably be about 50 mA, depending on the actual value i_ist the coil current. In this case, the residual i_res when exceeding the threshold of the switch 8th on a functional block 9 passed through. If the value of the actual value i_act of the coil current falls below the predetermined threshold of the switch 8th , becomes the function block 9 the constant "zero", which in a function block 10 is filed, passed through.

The desk 8th thus has only two positions that are switched depending on the threshold of the switch. Thus, as a function of the residual i_res or the difference between the actual value i_ist of the coil current and the theoretical value i_theo of the coil current, there is a change in the theoretically determined resistance value R_sp of the coil used to determine the theoretical value i_theo of the coil current. These method steps are in the reference number 11 marked area of the block diagram of the 3 shown in more detail.

The function block 9 is presently designed as an observer controller, via which the theoretical resistance R_sp of the coil in the form of an I-controller to the real electromagnetic drive system 1 is adapted. With this approach, in particular the phenomenon is taken into account that changes the ohmic coil resistance during operation with the increase of the coil internal temperature T_sp and the duration of the energization. Without adaptation, a deviation of the actual value i_act of the coil current and of the theoretical value i_theo of the coil current would result, which increases with the duration of operation of the electromagnetic drive system 1 a diagnosis of the operating state of the electromagnetic drive system 1 distort or would make impossible.

The observer controller 9 is designed such that influences of the mutual induction L_g, which are caused by the movement of the armature, in the adaptation of the theoretically determined cons value of the coil are not taken into account. That means over the observer controller 9 only slow persistent deviations between the actual value i_act of the coil current and the theoretical value i_theo of the coil current, which are detected via the residual i_res, are taken into account, while the rapid changes as a result of the mutual induction are used for the diagnosis.

The observer controller 9 in combination with the switch 8th causes a control of the theoretical resistance R_sp of the coil is omitted at only low actual values i_ist the coil current. However, currents are observed which are greater than the threshold of the switch 8th are, the resistance value R_sp via the observer controller 9 readjusted. This allows to create a correspondingly sensitive observer controller, since in particular when the coil current i_act falls, the observer controller 9 is switched off and the value of the residual i_res is set to zero when a minimum value of the actual value i_act of the coil current is reached. This ensures that the observer controller 9 at any time has the correct initial value and in the de-energized state or at low coil currents no control of the theoretical resistance of the coil performs, making the controlled system is much more stable.

In order to adapt the theoretical resistance value R_sp of the coil as a function of the respectively present operating state of the electromagnetic drive system 1 in the appropriate manner, takes place in the determination of the residual i_res in the function block 7 a sign reversal of the residual i_res, so that the linear model at any time in the "right" direction, ie by increasing or decreasing the theoretical resistance value R_sp the coil is adjusted.

Another functional block 12 represents the starting value or the reference resistance R_sp_0, which is at a startup of the electromagnetic drive system 1 is used as the starting value of the theoretical resistance value R_sp of the coil for determining the theoretical value i_theo of the coil current. With increasing regulation by the observer controller 9 is in the function block 13 the adaptation of the reference resistance R_sp_0 via the output values of the observer controller 9 carried out.

The adjusted theoretical resistance R_sp of the coil becomes a functional block 14 supplied as an input signal, which receives as a further input signal the theoretical value i_theo of the coil current. From these two input signals, a control voltage u_regel is determined, which in turn is a function block 15 is supplied as an input signal. The control voltage u_regel is in turn used to adapt the matched voltage u_anp used to determine the theoretical value i_theo of the coil current.

The one in the function block 13 determined or readjusted theoretical resistance value R_sp of the coil additionally provides a further output signal of the detector 3 The theoretical resistance value R_sp of the coil is used to calculate the coil internal temperature T_sp, which can be determined in a simple manner via the above-described linear relationship between the theoretical resistance value R_sp (T) of the coil and the temperature T_sp of the coil.

With the above-described procedure of tracking the theoretical resistance value R_sp of the coil, a continuous determination of the resistance R_sp and the temperature T_sp of the coil in contrast to stationary evaluation methods is possible because of the observer controller 8th only slow changes in the electromagnetic drive system 1 , such as the temperature influences are corrected.

This can be done preferably by the evaluation of the tracking resistance value R_sp and with the aid of a moving average, which is based on fluctuations of the observer controller 9 is tuned, a smoothed continuous resistance value of the coil can be provided. On the basis of this value or of the non-smoothed theoretically determined resistance value R_sp of the coil, the coil internal temperature T_sp can thus also be calculated with the equation for the heat resistance.

In 4 a further block diagram is shown, which is a second part of the detector 3 shows. About this part of the detector 3 For example, a lower threshold i_schw_u and an upper threshold i_schw_o are determined dynamically as a function of an excitation current i_anreg, which represents a predetermined desired value and is preferably generated by an electronic transmission control (EGS).

Exceeds that in the function block 7 certain residual i_res of the coil current one of the two thresholds i_sches_u, i_sches_o, is a fault of the electromagnetic drive system 1 recognized. For values of residual i_res less than the upper threshold or greater than the lower threshold, respectively become a "normal" operating behavior of the real electromagnetic drive system 1 recognized.

In the function blocks 16 . 17 In each case, a lower offset value i_offs u or an upper offset value i_offs_o is generated and used as input signal to further function blocks 18 . 19 fed. Furthermore, the exciter current i_anreg becomes two function blocks designed as low-pass filters, for example DT1 filters 20 . 21 supplied, the output values of the function blocks 20 . 21 further function blocks 22 . 23 be supplied as input values. In the function blocks 22 . 23 becomes the amount of filtered output values of the function blocks 20 . 21 formed and after a subsequent amplification with the offset values i_offs_u and i_offs_o applied, so that the upper threshold i_schw_o and the lower threshold i_schw_u are determined in dependence of the excitation current i_anreg. The evaluation of in 3 certain residual i_res together with the dynamically adjusted thresholds 4 enables the diagnosis of mechanical malfunctions.

In the 5a . 6a . 7a in each case a curve of the actual value i_act of the coil current and a profile of the theoretical value i_theo of the coil current over the time t is plotted, wherein, under the graphical representation of the coil current in the 5b . 6b . 7b in each case a corresponding representation of the residual i_res with the dynamically adjusted thresholds i_schw_u or i_schw_o is shown.

The in 5a illustrated course of the actual value i_ist the coil current represents a current profile in a "normal" behavior of the electromagnetic drive system 1 , as it occurs when applying an excitation current i_anreg, which has a movement of the armature result.

The in the beginning of the course of the in 5b Residuals i_res occurring fluctuations are due to a typical behavior of the current controller, which is properly disregarded by the correspondingly dynamically guided course of the thresholds without a corresponding error message of the detector or the detector downstream diagnostic module.

A good function of the electromagnetic drive system 1 Characterizing feature represents a negative deviation of the curve of the actual value i_ist of the coil current from the course of the theoretical value i_theo in the rising region of the two curves, since such a deviation indicates the induced by the movement of the armature mutual inductance L_g at the beginning of energization with the excitation current i_anreg. This negative current rash is in 5a and 5b recognizable with the area marked under I closer.

The in 6a illustrated course of the actual value i_ist the coil current has in a designated area closer to II a positive rash against the theoretical value i_theo of the coil current. The curves of the actual value i_ist and of the theoretical value i_theo then resemble each other after a short time. The course of the actual value i_act of the coil current corresponds to that in 6b illustrated course of Residuums i_res, which also has a positive rash in the range of the deflection of the actual value i_ist the coil current.

In exceeds this area II the course of the residual i_res the upper threshold i_schw_o. With increasing Time t returns the course of the residual i_res the coil current again into that of the upper threshold i_schw_o and the lower threshold i_schw_u band spanned back. On the basis of the first essentially the same curve of the actual value i_ist des Coil current and the theoretical value i_theo of the coil current in the rise of the curves and the later positive rash of the Actual value i_ist and the subsequent re-adjustment of the Both curves will be a mechanical anchor clamping at the beginning of the current supply the coil with the excitation current i_anreg with a later tearing of the Anchor detected.

The in 5a In the rise range of the curves of the actual value i_act and the theoretical value i_theo of the coil current in the region I, a recognizable negative current ripple is not recognizable in the rise range of the curves of the actual value i_act and i_theo. This suggests a stuck anchor. Only on the basis of the deviation of the course of the actual value i_ist from the course of the theoretical value i_theo in the region II in 6a , which is triggered by the tearing of the armature, a movement of the armature is detected.

In the 7a illustrated current waveforms of the actual value i_ist and the theoretical value i_theo of the coil current represent a so-called mechanical anchor terminals without tearing the anchor. This means that the armature despite the applied excitation current i_anreg over the entire time considered does not do any movement. Such a disturbance can be caused for example by too high contamination of the hydraulic oil and a resulting high friction of the armature in his leadership.

The anchor terminals can be detected in a simple manner by detecting a deviation from the course of the theoretically determined value i_theo of the coil current neither in the rise range nor in the further course of the current profile of the actual value i_act, the event exceeding the upper or lower threshold i_schw_o, i_schw_u by the in 7b shown course of Residuums i_res result. The absence of such an event indicates that movement of the armature has failed, suggesting an anchor clamp.

With the described method for performing a diagnosis of Operating state of an electromagnetic drive system is an online adaptation of the theoretically determined resistance value of the Coil current through the observer controller to the effect that based a permanent in real time feedback of the difference i_res the measured actual value i_act of the coil current and the theoretical one determined or the simulated output signal i_theo of the coil current an adaptation to the real system parameters is made.

there represents an evaluation of the by anchor movements in the coil inside induced voltage is a basis for the process in which in a computer unit via a model calculated, ideal current waveform with a measured Current signal is compared and a deviation is detected in real time. additionally a dynamic adaptation of detection thresholds is performed because the behavior of the real electromagnetic drive system over the linear model can only be reproduced within certain limits. This difference leads in particular with fast setpoint changes to significant differences or deviations between the model and the real system or between the actual value i_act of the coil current and the theoretical value i_theo of the coil current.

So that a false alarm is avoided in operating states which have large intentional deviations of the curves of the actual value i_ist and the theoretical value i_theo, it is provided via the dynamization of the detection thresholds to lower the lower threshold i_schw_u for a short time and briefly raise the upper threshold i_schw_o. This is preferably done by using low pass filters, for example the DT1 filter 17 . 18 ,

Furthermore, from the above the observer controller 9 adapted resistance value R_sp the Spuleninnentem temperature T_sp and a temperature T of existing in the vicinity of the electromagnetic drive system hydraulic oil of an automatic transmission can be determined in a simple manner, wherein the temperature determination in 8th strongly schematized by a functional block 26 is shown. This is particularly advantageous when it is not possible to arrange a separate temperature sensor due to confined spaces.

Referring to 8th is opposite 1 expanded block diagram of the electromagnetic drive system 1 shown. The actual value of the coil current i_act represents an input variable for the computer unit 2 and an empirically determined variable for determining a control deviation i_ab in relation to the excitation current i_anreg, which is a desired value specification of an electrical transmission control device (not illustrated in greater detail).

A deviation or a control deviation i_ab can result, for example, from a supply voltage delivered by a vehicle electrical system of a motor vehicle if this is too low in order to achieve the desired value input i_anreg. The control deviation i_ab in turn represents an input variable of a current controller 24 is, depending on the control deviation i_ab a corresponding actual value of the coil voltage u_ist adjusts the control deviation i_ab.

The current regulator 24 in the present case is a software component, whereby it is of course at the discretion of the skilled person to perform the current regulator as a function of the particular application case alternatively as a separate electronic component.

The electromagnetic drive system 1 or the electromagnetic actuator is driven with a corrected or adapted actual value of the coil voltage u_ist, whereupon a coil current i_ist in the coil. sets, which corresponds approximately to the setpoint input i_anreg. The setpoint input i_anreg corresponds to a value that corresponds to a desired event, that of the electromagnetic drive system 1 to be set in the transmission. This can, for example, a closing process be a hydraulically controlled with a hydraulic system of a transmission clutch of an automated transmission or an automatic transmission, when the electromagnetic actuator is an electro-hydraulic actuator, by means of which a desired pressure profile is set.

A controller setting of the current controller 24 takes place as a function of various parameters, one of these parameters being the resistance of the coil R_sp of the electromagnetic drive system 1 is.

With the above-described adaptation method for the theoretical mapping of the real coil resistance R_sp is advantageously on the in 8th illustrated coupling of the current controller 24 with the computer unit 2 a constant nominal behavior of the current controller 24 during changing operating states of the electromagnetic drive system 1 achieved. The parameter "Coil resistance" of the current controller 24 becomes the real system of the electromagnetic drive system 1 Operational condition is adjusted, so that an optimal current control of the coil by the current controller 24 is guaranteed.

This procedure is in 8th through a function block 25 represented, in which, depending on the theoretical resistance value of the coil R_sp, the current to the current operating state of the electromagnetic drive system 1 adaptively, the optimal current regulator parameters for the current regulator 24 be determined.

In order to is guaranteed that the Setpoint input i_anreg the transmission control device, for example to set a desired Pressure curve is output from the transmission control device, exactly and in case of deviations within a very short period of time can be readjusted.

1

electromagnetic drive system

2

computer unit

3

detector

4

filter

5

function block

6

Area

7

function block

8th

switch

9 10

function block

11

Area

12-19

function block

20

Function block, DT1 filter

21

Function block, DT1 filter

22 23

function block

24

current regulator

25 26

function block

I

Area

II

Area

i

amperage

i_ab

deviation

i_anreg

Excitation current, Setpoint

i_ist

actual value of the coil current

i_offs_u

lower offset value

i_offs_o

upper offset value

i_res

Residuum, Difference of the coil current

i_schw_u

lower threshold

i_schw_o

upper threshold

i_theo

theoretical Value of the coil current

L

inductance

L_g

mutual induction

R

resistance

R_sp

theoretical Resistance value of the coil

R_sp_0

Reference resistance

R_sp (T)

temperature-dependent resistance value the coil

u

tension

u_anp

adapted voltage

U_bat

Board supply voltage

u_ist

actual value the coil voltage

u_regel

control voltage

u_theo

theoretically determined tension

t

Time

T

temperature a transmission oil

T_sp

Coils inside temperature

T_sp_0

reference temperature

α

temperature coefficient

Claims (20)

Method for carrying out a diagnosis of an operating state of an electromagnetic drive system ( 1 ), in particular an electric actuator, with a coil and a longitudinally movably actuated by a magnetic field of the coil armature, wherein an actual value (i_ist) of a coil current, a theoretical value (i_theo) of a coil current and a coil current difference (i_res) between the actual value (i_ist ) and the theoretical value (i_theo), characterized in that - changes in the theoretical value (i_theo) which occur, for example as a consequence of a mutual induction (L_g) in the electric actuator, a detector ( 3 ) and / or - changes of the theoretical value (i_theo), which are caused in particular by temperature effects, by means of an observer controller ( 8th ). Method according to claim 1, characterized in that that the Diagnosis performed in real time becomes. Method according to Claims 1 and 2, characterized the existence theoretically determined resistance value (R_sp) of the coil used for Determination of the theoretical value (i_theo) of the coil current used becomes so dependent the coil current difference (i_res) is adapted that this is minimized. Method according to one of claims 1 to 3, characterized that the Adaptation of the theoretically determined resistance value (R_sp) above an amount of a threshold value (i_schw_u, i_schw_o) of the coil current difference (i_res) takes place. Method according to one of claims 1 to 4, characterized that at a determined coil current difference (i_res) greater than an upper detection threshold (i_schw_o) or less than a lower detection threshold (i_schw_u), an error detection is triggered. Method according to claim 5, characterized in that that the Detection thresholds (i_sches_o, i_schw_u) are adapted dynamically. Method according to claim 5 or 6, characterized that the Detection thresholds (i_schw_0, i_schw_u) depending on a given Excitation current (i_anreg) changed become. Method according to one of claims 1 to 7, characterized that the theoretical value of the coil current (i_theo) in dependence an inductance (L) of the coil is determined, one by a movement of the Anker's generated counterinduction (L_g) is disregarded. Method according to one of claims 1 to 8, characterized that as Start value of the theoretical resistance value (R_sp) of the coil Reference resistance value (R_sp_0) at a reference temperature is set which is in a map of an electrical control device is stored. Method according to one of Claims 1 to 9, characterized in that the adaptation of the theoretical resistance value (R_sp) of the coil via the observer controller ( 8th ), which adjusts the resistance value (R_sp) in the form of an I-controller to a real resistance value of the coil. Method according to claim 10, characterized in that an image of influences of a mutual induction on the actual value (i_ist) of the coil current on the theoretical value (i_theo) of the coil current by the observer controller ( 8th ) is omitted. Method according to one of Claims 1 to 11, characterized in that an actual value (u_act) of a pulse width-generated coil voltage is filtered. Method according to claim 12, characterized in that that out the filtered coil voltage (u_act) and one applied to the coil Voltage (u_bat) of a voltage source as a function of a switch-on time and a period time an averaged, effectively applied to the coil Voltage is determined. Method according to claim 13, characterized in that that one Adjustment of the determined effective coil voltage to a measurable effective Coil voltage occurs. Method according to claim 14, characterized in that that the theoretical value of the coil current (i_theo) in dependence the adapted one effective coil voltage (u_anp) is determined. Method according to claim 15, characterized in that that the Effective coil voltage adjusted with values from a map becomes. Method according to one of claims 1 to 16, characterized that one Temperature (T_sp) of the coil from the adapted theoretically determined Resistance value (R_sp) of the coil is determined. Method according to Claim 17, characterized in that the coil current (i_ist) is supplied via one of a current regulator ( 24 ) of the transmission control device regulated coil voltage (u_ist) is set. Method according to Claim 17 or 18, characterized in that a difference between the setpoint input (i_anreg) for the coil current of the gearbox control device and the actual value (i_ist) of the coil current is a control deviation (i_ab) for the current controller ( 24 ). Method according to one of Claims 1 to 19, characterized in that the current regulator ( 24 ) is adaptively adjustable depending on the resistance value (R_sp) of the coil determined in real time.