WO2011012376A1 - Method and device for time-controlled jamming detection - Google Patents

Abstract

For the time-controlled jamming detection for a displacing device having an electric motor (2) for window regulators, sliding roofs, or the like, wherein a value relative to a prevailing adjusting force (F) is monitored for exceeding a predetermined reference value, time intervals (T) in relation to current motor angular velocities (ω) generated continuously while operating the motor (2) are determined, and for every time interval an associated maximum time interval (T_max) is calculated on the basis of the minimum permissible angular velocity (ω _min) that is relative to the reference value, wherein then, when this maximum time interval (T_max) is achieved or exceeded by the respective time interval (T) in relation to the current angular velocity(ω), jamming is detected.

Description

description

Method and device for time-controlled jamming recognition

The invention relates to a method and a device for time-controlled Einklemmerkennung in an electric motor having adjustment for Fensterhe- ber, sunroofs or the like., A related to a current adjustment value is monitored for exceeding a predetermined reference value.

When the power-operated adjustment of components in motor vehicles, such as in particular for adjusting devices for electrically operated windows or sunroofs, a pinch protection system is provided to limit an excess force generated by the adjustment, which usually includes an electric motor. This anti-pinch protection system ideally detects jamming of an object, e.g. the arm of a person. According to the state of the art, during an adjustment process, changes in position of the adjusting device (or of the engine) or, at predetermined times, currently determined adjusting force values or correlated variables are compared with a predetermined reference force value (threshold value).

If the adjustment force applied by the motor increases above this reference value, this indicates an obstacle in the component travel and "jamming" is detected, movement of the component is then stopped and the motor is reversed.

In particular, in the conventional anti-trap protection systems, a suitably programmed microcontroller is used, which periodically executes a pinch detection algorithm; at the end there is a decision "Pinching not recognized" or "Pinching detected". As mentioned, there are two approaches for the period duration of this algorithm calculation: On the one hand, the anti-jamming algorithm is executed in a position-controlled manner, wherein, for example, in the case of a Hall sensor assigned to the motor or a magnetic wheel on the motor shaft with each Hall pulse Algorithm is started. Often such a system is also called speed-based anti-jamming protection. On the other hand, the anti-jamming algorithm can also be executed in a time-controlled manner, with the algorithm, ie computation, being started and executed at fixed predetermined times, for example every two milliseconds. Such a system is called time-based anti-jamming protection, in which case the motor current is generally the basic parameter for the anti-jamming calculation (in contrast to the motor speed). In both approaches, it is disadvantageous that a fixed, discrete time for starting the algorithm calculation is given; however, no interference detection is possible between every two calculations. This can now lead to situations where, between two such times, the optimum force threshold for the triggering is exceeded by the current adjustment force, and this exceeding is recognized only too late, the next time the algorithm is started. This results in systemic power fluctuations that can not be compensated, and this is undesirable and causes smaller safety reserves: namely, the force threshold must then be set correspondingly lower in order to secure trapping as securely as possible even with strong increases in the force curve between two algorithm start times detect, and without that an optimal triggering threshold, eg at 70 N, is exceeded. But if now the

Threshold value is set comparatively low, then the anti-pinch protection system tends to false triggering in Einklemmerkennung. This problem has not been solved in the prior art, and the force variations with the aforementioned adverse effects have been accepted in practice. It is an object of the invention to remedy this situation and to provide a method and a device for time-controlled Einklemmerkennung, as stated above, to achieve the simplest and most efficient way a secure Einklemmerkennung. The invention is based on the idea, instead of - as previously provided in the prior art - at fixed predetermined times or positions, e.g. at each pulse of a Hall sensor, perform a force calculation to provide variable time intervals for pinch detection, i. reverse the approach by using the triggering

Threshold, that is generally the reference value, a respective maximum period of time is calculated within which, for example, the next pulse of the Hall sensor would occur; If this is not done, jamming is detected.

To achieve the object, the invention thus provides a method and a device as defined in the independent claims. Advantageous embodiments and further developments are specified in the dependent claims.

With the present technique of pinch detection, the above objective can be met in an advantageous manner, based on simple calculations, ie simple algorithms to be implemented quickly be used to reliably detect a Einklemmfall can. In the process, variable time intervals are determined on the basis of the engine rotational speed or angular velocity, for example with the aid of the engine shaft, instead of being fixed as in the prior art

Coded disks, in particular of a magnetic wheel in conjunction with a Hall sensor. In this way, time pulses, in particular Hall pulses, are obtained as a function of the engine angular velocity, which determine the time intervals related to the angular velocity of the engine-in a variable form. For each time interval, at the same time an associated maximum time interval is calculated at the beginning, based on the maximum permissible force, ie the reference value, or in accordance therewith on the basis of the permissible minimum angular velocity, which is related to this reference value. If, during the execution of the algorithm or during the evaluation of the calculated time intervals, the maximum time interval expires earlier than the respective "reference" time interval related to the instantaneous motor angular velocity, then an entrapment situation is decided maximum time interval, the reference time interval, for example, the time between two Hall pulses expires, ie in the given example, the next Hall pulse already occurs, then the instantaneous adjusting force is smaller than the maximum allowable closing force, so the reference value, and the adjustment is continued.

It is particularly advantageous if the maximum time intervals are calculated on the basis of the measurement of the motor voltage, since this voltage measurement can be accomplished easily. The motor voltage is, while specifying a maximum permissible closing force, proportional to the permissible minimum angular velocity, as shown in more detail below. can be set and per motor revolution N reference time intervals or N Hall pulses (with N = I, 2, ...)

2π, in order to obtain the relation T _miiX =

auf das maximale Zeitintervall T_max zu schließen.

to close the maximum time interval T _max .

The maximum time intervals may be particularly simple based on the relationship

T max =! / ^(K l 'U _mot - k ₂ ^• F _max ⁾

to be calculated, in which

T _{max is} the respective maximum time interval

U _1nQ t is the instantaneous motor voltage

F _{max is} a predetermined force reference value and k] _, k ₂ , .... system constants

are.

With the beginning of each reference time interval, for example with each new Hall pulse of the Hall sensor, a microcontroller timer can now preferably be configured in such a way that, when the maximum permissible time duration T _max (or the maximum permissible reverb time) has expired Pulse duration)

Interrupt is triggered. Normally, however, before the end of this maximum time interval T _max, the following Hall pulse will occur, since normally there is no jamming and the actual adjustment or closing force F is smaller than the force threshold or the reference value F _max . In this

Case is again calculated at the end of the reference time interval or with the occurrence of the next Hall pulse, the maximum allowable time or pulse duration T _max , with the timer of the microcontroller is reconfigured. This happens regularly with each Hall pulse or generally with each new reference time interval (for example, can also pacitive or optical encoders are used to determine the angular speed of the motor); the exceptional case arises when jamming is present - in this case, as mentioned, the sequence of T _{max is} triggered by a timer interrupt, thereby stopping the motor or initiating its reversing.

The invention will be further explained by means of preferred embodiments and with reference to the drawings. In detail in the drawing:

Figure 1 is a diagram showing the process of a Einklemmerkennung according to the prior art, wherein in the graph, the force F in Newton (N) over time in milliseconds (ms) is plotted.

2 shows a block diagram of a drive device, for example for a window lifter or a sunroof, in connection with a device according to the invention;

FIG. 3 is a flowchart for illustrating the procedure according to the invention; FIG. and

Fig. 4 in a diagram closing force F over time t the procedure in the inventive technique.

FIG. 1 shows a diagram which shows a profile of the clamping force F [N] over the time t [ms] in the case of a clamping operation in an adjusting device of a window lifter or sliding roof of a motor vehicle with regard to anti-pinching protection according to the prior art illustrated. Specifically, in this example, at fixed time intervals Δt, for example every two milliseconds, a calculation is made correspondingly. The predetermined anti-jamming algorithm is carried out in order to calculate the respective closing force F and to compare it with a predetermined threshold value or reference value F _max . In the time interval .DELTA.t shown by way of example in FIG. 1, a differential force .DELTA.F results, which is thus given between two consecutive calculations of the anti-pinch detection and amounts to approximately 8 N in the example shown. Assuming now the optimum or desired triggering threshold for a force F _max = 61 N, the pinching detection in the first example (where a force value F = 60 N is determined) would not yet respond in the example shown, whereas the closing force F would be at the next calculation occurring two milliseconds later already

F = 68 N, ie 7 N above the desired value (61 N).

A similar disadvantageous pinching evaluation results when the anti-jamming algorithm is executed in a position-controlled manner, whereby the optimum threshold value can also be exceeded between two consecutive calculations so that the jam detection takes place too late, if the instantaneous force value is too high.

In order to remedy this situation, lower thresholds have been provided in the past, but the known systems then have a higher tendency to false triggering during pinch detection.

In contrast, the invention is based on the idea of calculating a maximum time interval based on the triggering force in response to the engine angular velocity ω, for example with each pulse of an angular velocity sensor associated with the engine, in particular a Hall sensor. within which the next pulse of the angular velocity sensor, eg Hall sensor, must occur during normal operation, so that a decision is not made on a pinching situation. This maximum time interval T _max can be loaded into a timer of a microcontroller, as will be explained in more detail below with reference to FIG. 2, in the case that the next measuring pulse, ie the time interval T related to the angular velocity, is later than the maximum Time interval T _max expires, stopping the engine and a reversing movement, for example, the powered sunroof, window or the like. initiate. In this case, a temporal resolution in the microsecond range is possible, in contrast to the time calculations according to the prior art at intervals of a few milliseconds, ie the resolution is a factor of 1000 better than in the prior art; Therefore, the otherwise occurring force fluctuations can be avoided.

If the use of a timer is disadvantageous for software-technical reasons, it can be checked at position-controlled anti-trap systems at defined time intervals (eg 2 ms) as to whether the maximum time interval T _{max has} already expired. In the case of expiration pinching is detected. This approach corresponds to the prior art described in time-controlled systems, but is an improvement in position-controlled systems, since the distance between two position events (in particular pulses of the Hall sensor) is often - especially in the pinching situation - much larger than this period. Therefore, this approach does not achieve the optimum trip point as when using a timer, but less

Variations than in a position-controlled system. Before now goes into detail on the block diagram of FIG. 2, is still based on the physical conditions in an electric motor, the relationship between the voltage U _mo - _| - Be explained on the engine, the armature current I of the motor and the angular velocity ω of the engine as follows.

The known static motor _equation U _Uot = k _a -ω + RI leads to resolution after motor current I.

_I _U _Mot -k _ω -ω

 R

In this mean:

UMot- .. Motor voltage

 I motor current (armature current)

k _ω .... proportionality factor (motor constant) and

R anchor resistance.

If another motor constant k _m is defined as the proportionality factor, the torque M of the motor through this constant k _m proportional to the armature current I:

With the radius r of the cable winding of the motor and the respective given transmission ratio ü, the force F results on the cable and thus on the sunroof, windows, etc. as follows: rr - R

Die maximal zulässige Schließkraft F_max entspricht dabei der gesetzlichen Forderung von beispielsweise 100 N oder einem darunter liegenden Zielwert des Fahrzeugherstellers (z.B. 70 N) . Dabei müssen auch noch additive Kräfte wie die Reibung an den Dichtungen berücksichtigt werden, was beispielsweise den Grenzwert wieder auf 90 N erhöhen kann. Jedenfalls handelt es sich hierbei um eine jeweils vorgegebene und somit bekannte Größe. From this equation for the closing force F at equating the closing force F equal to the maximum allowable closure force F _max, the minimum allowable rotational speed ω _mj, by conversion, _ _n be written as follows:

The maximum permissible closing force F _max corresponds to the legal requirement of, for example, 100 N or an underlying target value of the vehicle manufacturer (eg 70 N). Additive forces such as friction on the seals have to be taken into account, which can, for example, increase the limit value to 90 N again. In any case, this is a given and thus known size.

From the above equation for the minimum speed ω _mj _ _n , the maximum permissible time duration T _max between two successive pulses of the (Hall) sensor can now be calculated. If N (with N = I, 2, ...) denotes the number of measuring pulses per motor revolution, then: _τ _ ₌ J-JfL ₌ I. 2π-ü-k _^ -k.

 Max

Nω_ "NU _Mot -u-k _m -F_-rR

Most terms of this equation are known system constants. Thus, the equation with the composite system constants k _] _ and k2 can be simplified as follows K "U _Mot - k ₂ ^■ F _max

In it, F _max is given and U _mo - _| - can be simple

Be measured way.

For each successful (Hall) pulse, a microcontroller timer is now configured in such a way that an interrupt would be triggered when the maximum permissible Hall pulse duration T _max expires. In the normal case, however, the following Hall pulse will occur before this expiration of T _max , ie the time interval T related to the angular velocity co will expire, since there is no pinching and the instantaneous adjusting force F is less than F _max . In this case, the maximum pulse duration T _{max is} calculated again at the next pulse in order to reconfigure the timer. This happens regularly at each

Hall pulse (general: measuring pulse). The exception is the case of pinching. Here, as already mentioned, a timer interrupt is triggered and reversing of the motor is initiated.

In Fig. 2 is a device 1 for timed Einklemmerkennung according to the procedure described above in connection with a drive device for adjusting a window regulator, sliding roof or the like. However, only the parts of interest here, namely a motor 2 together with the associated motor drive unit 3, are illustrated by this drive device. By way of example, the motor 2 is assigned a code wheel, for example a magnetic wheel 4, with which a Hall sensor 5 (or, in the case of another code wheel, a corresponding other sensor) cooperates. This sensor 5 (hereinafter, for the sake of simplicity, without limitation, is always of a Hall sensor 5 spoken), for example, gives off N Hall pulses per motor revolution, these Hall pulses on the angular velocity ω of the motor 2 related time intervals T (see Fig. 4) define.

The Hall pulses are detection means 6 for determining whether these time intervals T are each shorter than an associated, respectively recalculated maximum time interval T _max , fed, these detection means 6 may be formed for example by a microcontroller. These detection means (or the microcontroller 6) contain (or contain) a timer 7 and, upstream of it, means or a calculation module 8 for calculating the respective maximum time interval T _max . On the other hand, the (Hall) sensor 5 forms means 9 for monitoring the motor angular velocity ω and determining related time intervals T. The maximum time interval T _max is calculated in the calculation module 8 according to the above-mentioned relationship for T _max , where the value the motor voltage U ₁₁₁₀ -I ₁ of voltage measuring means 10, which are connected for example to the terminals of the motor 2, is supplied. (However, it is also possible, for example, to use the supply voltage of the electronic module for this purpose, which approximately corresponds to the voltage at the motor.) An input unit 11 is also provided for fixing fixed values, such as the respective reference force F _max or the system constants k] _, k2 Here, it is also conceivable that the system constants k] _, k2 on the basis of the other constants mentioned in the above relationships, such as armature resistance R, motor constant k _ω , transmission ratio ü, radius r of the cable winding, etc It is also conceivable that the system constants k] _ and k2 can be predicted empirically in advance Startup of the system to determine and store, so that the unit 11 then has these sizes as well as on the respectively input reference value for the closing force ^F max.

In operation, the calculation module 8 thus calculates the maximum time interval T _max for each time interval T or for each Hall pulse on the basis of, in particular, the measured motor voltage U _1nQ t and the parameters F _max , k] _, k2, and the timer then becomes 7 is set via a connection 12, ie the maximum time interval T _max is loaded into the timer 7. If now the next Hall pulse from the Hall sensor 5 is delivered in time, so this is supplied via a reset input to the timer 7, there is a new calculation of the maximum time interval T _max in the module 8, and the timer 7 is set again. If, however, the next Hall pulse is emitted by the sensor 5 only after expiration of the maximum time interval T _max , then the timer 7 already triggers a corresponding drive signal to the motor drive unit 3 with the expiry of the maximum time interval T _max Connection 13 and then the motor drive unit 3 then stops in a conventional manner the motor 2 or initiates its reversing. The procedure, as described above, will now be illustrated with reference to the flowchart of Fig. 3.

According to FIG. 3, after a starting step 20 it is provided that, according to a block 21, the maximum time interval T _max is calculated. This is followed, according to block 22, by the configuration of the timer 7, and according to a decision field 23, it is then determined whether the momen- tane time interval T, specifically the next Hall pulse, expires earlier (or occurs earlier) than the maximum time interval T _max expires. If so, the system returns to block 21 and the procedure described is repeated. This is generally done until the motor is stopped at the end of the movement without jamming. However, if jamming occurs, query field 23 will indicate that T _max expires before, ie timer 7 expires before the next Hall pulse occurs. In this case, a jamming is detected, see block 24, and according to block 25, the reversing of the motor 2 is initiated.

In FIG. 4, in a diagram comparable to that of FIG. 1, but without dimensions, a force profile 30 is illustrated during an adjusting movement, for example, of a window lifter or sunroof, monitoring of pinching. At a time tg, it was assumed that the last Hall pulse occurred at the Hall sensor 5 (FIG. 2), whereby, triggered, the associated maximum time interval T _{max was} calculated as described. If the next Hall pulse at time t] _, this results in the on

Angular velocity ω related time interval T, as shown in Fig. 4, and this time interval T runs in the example shown earlier than the maximum time interval T _max . However, if the next Hall pulse, rather than the time t] _, appears until time t] _ ', a time interval T' which relates to the angular velocity ω and which expires later than the maximum time interval T _{max would result} . in this case, contrary to the former case, trapping (due to the force F _max being exceeded) would be inferred. The described method therefore leads to one to t _] _ '- (t _Q + T _max ) earlier detection of pinching against the position-controlled prior art.

Assuming, however, the next Hall pulse occurs at time t] _, similarly as described above, a now associated maximum time interval T _{max is again} calculated

(not shown in Fig. 4), and the next Hall pulse occurs, for example, at time t2, repeating the above explained in connection with the times t _] _ and t _] _ 'compared to T _max .

Claims

claims 1. A method for time-controlled Einklemmerkennung in an electric motor (2) having adjusting device for windows, sunroofs or the like. in which a value related to a current adjustment force (F) is monitored for exceeding a predetermined reference value, characterized in that it refers continuously to the instantaneous engine angular velocity (ω) resulting during operation of the engine (2) Time intervals (T) are determined and for each time interval, an associated maximum time interval (T _max ) based on the minimum allowable angular velocity (&> _m -j_ _n ), which is based on the reference value is calculated, and if this maximum time interval (T _max ) is reached or exceeded by the respective time interval (T) related to the instantaneous angular velocity (co), jamming is detected. 2. The method according to claim 1, characterized in that on the instantaneous angular velocity (co) related time intervals (T) by Hall pulses of a motor (2) associated Hall sensor (5) are defined. 3. The method according to claim 1 or 2, characterized in that the maximum time intervals (T _max ) based on the measurement of the motor voltage (U ₁₁₁₀ -I ₁ ) are calculated. 4. The method according to claim 3, characterized in that the maximum time intervals (T _max ) based on the relationship T max =! / ^(K l 'U _mot - k ₂ ^• F _max ⁾ to be calculated, in which T _{max is} the respective maximum time interval U _1nQ t is the instantaneous motor voltage F _{max is} a specified force reference value and k] _, k2 .... system constant  are. 5. The method according to any one of claims 1 to 4, characterized in that the respective maximum time period (T _max ) in a timer (7) of a microcontroller (6) is loaded, in its expiry, before the expiry of the current angular velocity (co) related time interval (T), an interrupt to initiate a Rever- sierbewegung the motor (2) is generated. 6. Device (1) for time-controlled Einklemmerkennung in an electric motor (2) having adjusting for windows, sunroofs or the like. in which a value related to a current adjustment force (F) is monitored for exceeding a predetermined reference value, characterized by means (9) for monitoring the motor angular velocity (co) and determining related time intervals (T), by means (8 ) for calculating a respective maximum time interval (T _max ) for each time interval (T) related to the angular velocity (ω) and detecting means (6) for determining whether the respective maximum time interval (T _max ) precedes the associated one the angular velocity {co) related time interval (T) expires so as to detect pinching. 7. Apparatus according to claim 6, characterized in that the means (9) for monitoring the angular velocity (ω) and determining the related timing tervalle (T) having a motor (2) associated Hall sensor (5) whose Hall pulses define the time intervals (T). 8. Apparatus according to claim 6 or 7, characterized by means (10) for measuring the motor voltage (U _mo t) 'which is supplied to the means (8) for calculating the respective maximum time interval (T _max ) for its calculation. 9. Apparatus according to claim 8, characterized in that the means (8) for calculating the respective maximum time interval (T _max ) are set up, the respective maximum time interval (T _max ) based on the relationship T _max = 1 / U ₁ ^• U _{mo t} - k ₂ ^• F _max )  to calculate in which T _{max is} the respective maximum time interval U _1nQ t is the instantaneous motor voltage F _{max is} a predetermined force reference value and k] _, k ₂ , .... system constant  are. 10. Device according to one of claims 6 to 9, characterized in that the means (8) for calculating the respective maximum time interval (T _max ) are connected to a timer (7) of a locking means (6) provided as a micro- rocontrollers to load the respective maximum time interval (T _max ) into it, the timer (7) at a lapse of the respective maximum time interval (T _max ) before expiry of the associated angular velocity (co) related interval (T) generated terrupt to initiate a reversing movement of the motor (2).