JP4510434B2 - Method for determining start segment of rotation angle sensor having periodic characteristic curve and rotation angle sensor device - Google Patents

Description

  The present invention relates to a method for determining a start segment of a rotation angle sensor having a periodic characteristic curve and a rotation angle sensor device corresponding thereto.

  Rotational angle sensors are used in many applications to measure the angular position of a rotating object. In this case, the measurement is generally performed in a non-contact manner by means of a magnetic or optical transmitter. An application in the automotive field is, for example, the determination of the steering angle or steering wheel angle of an automobile.

  FIG. 1 shows a measuring device for measuring the rotation angle of a rotary shaft 1 known from the prior art, which can be rotated in the direction of arrow A. FIG. The illustrated measuring device includes a sensor (rotation angle sensor) 2 disposed at an end of the rotating shaft 1, and the sensor 2 has an evaluation unit 4 connected to the sensor 2. In this case, the sensor 2 is fixedly disposed. Cooperate with the transmitter 3. In this case, the transmitter 3 includes a permanent magnet, which induces, for example, a voltage in the sensor 2. As the sensor element, for example, a Hall sensor, a magnetoresistive sensor (MR sensor), a magnetic transistor, or the like may be used.

In a motor vehicle, a typical rotation angle sensor often used to measure the steering wheel angle has a characteristic curve as shown, for example, in FIG. 2a. As can be seen from the figure, sensor signal α _S of sensor 2 includes a full angle range (eg, steering wheel pivot angle α _L between −800 ° and + 800 °), so sensor 2 (sensor 2 is signal processing). The steering wheel angle α _L is actually output at the output of (which may have a unit). Thus, the steering handle is pivoted from the 0 position (α _L = 0 °) to the right stopper (eg, α _L = 800 °) and then returned to the 0 position, as shown at 6 in FIG. 2b. The steering motion is uniquely formed by the sensor 2. In this example, since a digitized signal is used, the sensor signal 7 is shown stepwise in FIG.

  The sensor signal 7 may be post-processed by another device (evaluation unit 4) arranged in the vehicle such as a traveling dynamic characteristic control device (for example, ESP: electronic stability program).

The sensor 2 having a linear characteristic curve over a wide measuring range has the disadvantage that it is relatively complex and therefore expensive.
Therefore, it is desirable to use other standard sensors with a simple configuration for angle measurement that do not require counting means and the direction of rotation in particular. Such a sensor can be formed, for example, from a number of MR sensor elements.

A sensor characteristic curve of such a rotation angle sensor is shown by way of example in FIG. 3a. As can be seen from the figure, the linear measurement range of the rotation angle sensor includes only a partial range (from −p to + p) of the entire measurement range with respect to the rotation angle α _L. For rotation angles α _L exceeding a partial measurement range (for example between −120 ° and + 120 °), the sensor characteristic curve 5 is periodically repeated.

During each period of the characteristic curve 5 that can be represented as a segment S, each characteristic curve 5 exhibits a characteristic curve abrupt change 8. When the partial measurement range of the rotation angle sensor includes, for example, an angle between −120 ° and + 120 °, the rotation angle α _L existing within this range is uniquely indicated. On the other hand, for example, at a rotation angle of 121 °, the rotation angle sensor supplies an output signal α _S corresponding to the rotation angle of −119 °.

  Thus, the rotational movement of the shaft as shown at 6 in FIG. 3b will result in a sensor signal 7 having a sudden signal change. Such sensor signal 7 cannot be directly processed by a lower-level device (evaluation unit 4) such as traveling dynamic characteristic control because the sensor signal 7 is not unambiguous.

  In order to generate a reconstructed (unique) sensor signal 9, the sensor signal 7 is monitored by a threshold value, and when a sudden signal change (ad; FIG. 4a) occurs, the threshold value is specified. Methods may be used. Depending on the direction of the signal abrupt change, this signal abrupt means a transition from one segment to the next higher segment or the next lower segment. Segment transitions are recorded by the segment counter, which increments or decrements the set segment value SN (FIG. 4b). From the segment value SN and the actual measurement angle, the evaluation unit 4 can easily calculate the reconstructed angle signal 9 (FIG. 4c), which is an unambiguous motion diagram after the initialization of the sensor 2. To reproduce.

  In the case of steering wheel angle measurement in an automobile, at the time of initialization of the sensor 2 (for example, ignition on), it is usually assumed that the rotating shaft 1 exists near the 0 position of the shaft. However, if the axis of rotation 1 is present in a sensor initialization other than segment S0 (eg at 400 ° or 500 °), the sensor signal 7 must be correspondingly corrected for this zero offset.

  An object of the present invention is to provide a method capable of determining a unique overall angle related to the 0 position of a rotating object from a sensor signal of a rotation angle sensor having a periodic characteristic curve, and a rotation angle sensor device corresponding thereto. Is to provide.

  According to the present invention, there is provided a rotation angle sensor that has a periodic characteristic curve including a large number of segments, in which a characteristic curve abruptly changes between segments, and that measures a limit angle range limited by a minimum segment and a maximum segment. In the method for determining the start segment, the step of reading the sensor signal into the evaluation unit, the step of measuring positive and negative signal sudden changes of the sensor signal, the step of generating a numerical value when the signal sudden change is specified, and the maximum number of segments And a maximum valid start segment from the maximum number determined after initialization of the rotation angle sensor, and from the minimum number of segments and the minimum number determined after initialization of the rotation angle sensor, Steps to calculate the minimum valid start segment and the maximum valid start segment is the minimum valid start segment When equal to cement, and determining a start segment, a.

  In addition, according to the present invention, a rotation having a periodic characteristic curve including a large number of segments, in which a characteristic curve suddenly changes between segments, and measuring only a limited angle range between the minimum segment and the maximum segment. In a rotational angle sensor device comprising an angle sensor and an evaluation unit to which a sensor signal having a signal sudden change is supplied, the evaluation unit measures positive and negative signal sudden changes in the sensor signal, and identifies the signal sudden change When generating the numerical value, calculating the maximum valid start segment from the maximum number of segments and the maximum number determined after initialization of the rotation angle sensor, and the minimum number of segments and initial rotation angle sensor Calculating a minimum valid start segment from the minimum number determined since conversion, and determining a start segment therefrom; and The capacitors signal or therefrom derived signal is formed so as to allow correct correspondingly.

  The essential idea of the present invention is to limit the possible segments as start segments during the rotational movement, and signals that are not valid considering the sensor output signals present, i.e. signals that cannot be a problem as start segments Are to be excluded sequentially. In the initialization of the rotation angle sensor, the start segment has not yet been determined and will exist between the maximum segment SNmax and the minimum segment SNmin. The segments SNmin and SNmax are determined by predetermined measurement range limits (for example, the steering wheel right and left stops at -800 ° and + 800 °). During rotational movement, this range is limited until the start segment can be uniquely determined.

  For example, when a signal sudden change from the segment SN to the segment SN + 1 is performed in the sensor signal due to rotational movement, the segment SN cannot be the maximum segment. Therefore, the segment SNmax is excluded because it is not valid as a start segment. The same applies to the minimum segment SNmin in the sudden change of the sensor signal, which means a transition from segment SN to segment SN-1. In this way, possible segments as start segments (initially this may be all segments between the minimum segment SNmin and the maximum segment SNmax) are stepped until the start segment can be accurately determined. Can be limited to each.

  In this case, the method for determining a start segment according to the invention essentially comprises the following steps: reading a sensor signal having a signal sudden change into the evaluation unit, which evaluates positive and negative in the sensor signal. A numerical value Z can be generated when a sudden signal change is measured and a sudden signal change is identified. Here, the numerical value Z is a counter value obtained by counting the number of segment shifts after the rotation angle counter is initialized. The evaluation unit calculates the maximum valid start segment SNplmax from the maximum number of segments SNmax and the maximum number Zmax determined after the initialization of the sensor, and the minimum number of segments SNmin and the initialization of the rotation angle sensor The minimum valid segment SNplmin is calculated from the determined minimum number Zmin. After a sufficient number of segment transitions, when the minimum valid start segment SNplmin and the maximum valid start segment SNplmax match, this detects the start segment (ie, the segment present in the rotation angle sensor initialization). The sensor signal or a signal derived therefrom, such as a reconstructed angular signal, can now be corrected for the start segment.

  In particular, the sensor signal having a signal abrupt change is preferably reconstructed into a unique angular signal based on the determined number of signals, and the reconstructed angular signal is corrected with respect to the start segment.

  The rotation angle sensor device according to the present invention includes a rotation angle sensor having a periodic characteristic curve including a large number of segments in which a characteristic curve sudden change occurs between the segments, and an evaluation unit. Only a limited angular range between the largest segments is measured. In this case, the evaluation unit to which the sensor signal is supplied is formed so as to be able to perform any of the above methods.

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

Reference is made to the opening description for the description of FIGS.
FIG. 5 shows a rotation angle sensor device including a rotation angle sensor (steering handle angle) 2 having a periodic characteristic curve 5 (FIG. 3 a) and a travel dynamic characteristic control device (ESP) as the evaluation unit 4.

  In this case, the evaluation unit 4 converts the non-unique sensor signal (see FIG. 4a) supplied from the rotation angle sensor 2 into the first reconstructed sensor signal 9 (see FIG. 4c) (signal reconstruction means). 27), and the reconstructed sensor signal 9 is corrected with respect to the start segment (start segment correction means 28). Here, the start segment detecting means 29 is used for detecting a start segment (= 0 offset). The result of this method is, for example, a unique steering handle angle Lwin that can take values within the entire measurement range between -800 ° and + 800 °.

  The detection of the start segment (the segment in which the steering shaft without the rotation shaft 1 exists in the initialization of the rotation angle sensor 2) in the start segment detection means 29 will be described in detail below as an example.

In the initialization of the rotation angle sensor 2 (ignition on), the steering handle may be in any position, i.e. the associated segment S is not known. That is, the start segment can exist within a range between SNmin and SNmax. Normally, the steering handle is in the 0 position (0 °), so the numerical value is in the start segment. Z = 0 Start from being assigned. As described above, the numerical value Z is incremented when the negative signal abrupt changes a and d are present in the sensor signal 7 and decremented when the positive signal sudden changes b and c are present. If a negative signal sudden change a occurs at time t1 (see FIG. 4a), the numerical value Z is incremented accordingly (see FIG. 6). From this, at time t1, the start segment is the largest segment SNmax = 5 It can be speculated that it was not. Therefore, the largest segment SNmax = 5 Can be excluded as invalid (see shaded area).

It is assumed that the numerical value Z suddenly returns to 0 at time t2. This makes it impossible to obtain new knowledge about possible start segments. Only at time t3 when the numerical value Z is decremented to the value -1 based on the positive signal sudden change c, the smallest segment SNmin = -5 Can be excluded as a valid start segment.

After that, only the steering movement is performed, from which no new knowledge about possible start segments can be obtained. Only at the time t5 when the numerical value Z suddenly returns to the value -2 can the segment S- ₄ also be excluded as a possible valid start segment. The possible segments for the start segment are further limited in a sufficiently large steering movement until the final possible segment S still remains as the start segment. When all segments S between SNmin and SNmax have been executed, the start segment can be determined.

  In the following, a mathematical representation of the above method that can be performed by the evaluation unit 4 will be described. The start segment may initially be each segment between the measurement range limits SNmin and SNmax in the initialization of the rotation angle sensor 2. That is, all possible segments S are valid in this state. When a segment sudden change a-d occurs, the maximum and minimum valid start segments SNplmax, SNplmin can be determined, in which case:

Here, Zmax and Zmin are the maximum number or the minimum number Z generated after the rotation angle sensor 2 is initialized (ignition-on).
After a sufficiently large number of segment transitions via multiple steering handle rotations, the reasonable range is limited to only one valid segment, and SNplmax = SNplmin = start segment When is established, a start segment is detected.

It is an approximate principle figure showing an example of a measuring device for measuring a rotation angle of a rotating shaft. 2a is a characteristic curve diagram of a rotation angle sensor known from the prior art, and FIG. 2b is a sensor signal diagram of the rotation angle sensor of FIG. 2a. 3a is a sensor characteristic curve diagram of a known rotation angle sensor having a periodic characteristic curve, and FIG. 3b is a sensor output signal diagram of the sensor of FIG. 3a. 4a is a sensor signal diagram of a rotation angle sensor having a periodic characteristic curve, FIG. 4b is a count value diagram of a segment counter when the signal of FIG. 4a is present, and FIG. 4c is a reconstruction angle signal. FIG. It is a systematic diagram regarding the reconfiguration of a sensor signal of a sensor having a periodic characteristic curve and zero point correction. FIG. 6 is a diagram showing a full angle range (for example, an automobile steering wheel turning angle of −800 ° to + 800 °) between a minimum segment SNmin and a maximum segment SNmax that can be measured by the rotation angle sensor 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating shaft 2 Rotation angle sensor 3 Transmitter 4 Evaluation unit 5 Characteristic curve 6 Motion diagram 7 Sensor signal 8 Characteristic curve sudden change 9 Reconstructed sensor signal 27 Signal reconstruction means 28 Start segment correction means 29 Start segment detection means S Segment -p, + p Segment limit Z Value α _S sensor angle α _L measurement angle t Time SNmin Minimum number of segments SNmax Maximum number of segments SNplmin Minimum valid segment SNplmax Maximum valid segment

Claims (4)

A characteristic curve sudden change (8) occurs between the segments (S), which has a periodic characteristic curve (5) including a large number of segments (S), and is limited by the minimum segment (SNmin) and the maximum segment (SNmax) In the method of determining the start segment (S) of the rotation angle sensor (2) that measures the limited angle range,
Reading the sensor signal (7) into the evaluation unit (4);
Measuring positive and negative signal abrupt changes (ad) of the sensor signal (7);
Generating a numerical value (Z) that is assigned 0 to the start segment (Z = 0), incremented when a negative signal sudden change exists, and decremented when a positive signal sudden change exists ;
The maximum valid start segment (SNplmax) is calculated from the maximum number of segments (SNmax) and the maximum number (Zmax) of the numerical values (Z) determined after the initialization of the rotation angle sensor (2), and the minimum Calculating a minimum valid start segment (SNplmin) from the number of segments (SNmin) and the minimum number (Zmin) of numerical values (Z) determined after initialization of the rotation angle sensor (2);
Determining a start segment (S) when a maximum valid start segment (SNplmax) is equal to a minimum valid start segment (SNplmin);
A method for determining a start segment of a rotation angle sensor having a periodic characteristic curve.   2. The sensor signal according to claim 1, wherein the sensor signal having a sudden signal change is reconstructed into a unique angular signal based on the determined numerical value. Decision method. A characteristic curve sudden change (8) occurs between the segments (S), the periodic characteristic curve (5) including a number of segments (S), and the minimum segment (SNmin) and the maximum segment (SNmax) In a rotation angle sensor device comprising a rotation angle sensor (2) for measuring only a limited angle range between and an evaluation unit (4) to which a sensor signal (7) having a sudden signal change (ad) is supplied,
Evaluation unit (4)
Measuring positive and negative signal abrupt changes (ad) in the sensor signal (7);
Generating a number (Z) that is assigned 0 to the start segment (Z = 0) and is incremented when there is a negative signal sudden change and decremented when there is a positive signal sudden change ;
The maximum valid start segment (SNplmax) is calculated from the maximum number of segments (SNmax) and the maximum number (Zmax) of the numerical values (Z) determined after the initialization of the rotation angle sensor (2), and the minimum Calculate the minimum valid start segment (SNplmin) from the number of segments (SNmin) and the minimum number (Zmin) of the numerical value (Z) determined after initialization of the rotation angle sensor (2), and start from now Determining the segment (S) and correcting the sensor signal (7) or the signal derived therefrom (9) correspondingly,
The rotation angle sensor device is characterized in that it is formed so as to be possible. The evaluation unit (4) first reconstructs the sensor signal (7) with a sudden signal change (ad) into a unique angular signal (9) and starts the reconstructed angular signal (9) The segment (S) is corrected for the rotation angle sensor device according to claim 3.

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