Method for initializing a rotation angle measurement system and rotation angle measurement system

Abstract

The present invention relates to a method for initializing a rotation angle measurement system (10) and a rotation angle measurement system having a corresponding initialization unit (38), which initializes the rotation angle measurement system by setting a defined initialization angular position of a rotor unit (18) relative to a stator unit (20), reading out stored partial rotation actual count values ​​(Un) indicating the relative rotation of the rotor unit relative to the stator unit in terms of the number of (360° / N) partial rotations, determining a real sub-interval value (HSn) indicating in which (360° / N) sub-interval of one whole rotation the rotor unit is located relative to the stator unit based on the partial rotation actual count value, and incrementing or decrementing the stored real sub-interval value when the real sub-interval value does not match a target sub-interval value (HS1 to HS4) assigned to the defined initialization angular position, thereby providing a rotation angle measurement system that can be reliably and simply initialized.

Description

[Technical Field]

[0001] The present invention relates to a method for initializing a rotation angle measurement system and a rotation angle measurement system for detecting the rotational movement of a shaft, comprising: a rotatable rotor unit designed to be mounted for rotation with the shaft and having a plurality of permanently excited magnets; a fixed stator unit having a Wiegand multi-turn sensor, a data storage device and an evaluation unit; and a single-turn sensor unit capable of detecting the angular position of the rotor unit with respect to the stator unit. The evaluation unit is connected to the Wiegand multi-turn sensor, the single-turn sensor unit and the data storage device and is capable of detecting the relative rotation of the rotor unit with respect to the stator unit in (360° / N) partial turns (where N=2 n (n=1, 2, 3, ...)) and an actual angular position value indicating the relative angular position of the rotor unit with respect to the stator unit, and stores the determined actual count of partial rotations and the determined actual angular position value in a data storage device. [Background technology]

[0002] Such rotation angle measurement systems are well known in the art and are used in particular for controlling and monitoring electric motors, in particular servomotors, in machines, plants or vehicles. Rotation angle measurement systems are also often referred to as angle measuring devices, rotation angle sensors or rotary encoders.

[0003] In a rotation angle measurement system with a Wiegand multi-turn sensor, particularly one in which the rotor unit and stator unit are separate assemblies, the rotor unit with a permanently excited magnet may unexpectedly move relative to the stator unit with the Wiegand multi-turn sensor during transportation and installation of the rotation angle measurement system, causing the Wiegand multi-turn sensor to generate unintended counting pulses. This typically results in an increment or decrement of the actual partial rotation count value stored in the data storage device, even without an external power source for the rotation angle measurement system. Therefore, the actual partial rotation count value of such a rotation angle measurement system may become indefinite after installation at the site of use.

[0004] However, since the actual partial rotation count values ​​stored in the data storage device are typically only incremented or decremented during operation of the rotation angle measurement system, it is essential for the rotation angle measurement system to have the actual partial rotation count values ​​determined after installation. Therefore, the rotation angle measurement system is typically initialized after installation to set a predetermined initial state. Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above, an object of the present invention is to provide a rotation angle measurement system that can be initialized reliably and easily. [Means for solving the problem]

[0006] This problem is solved by a method for initializing a rotation angle measuring system having the features of claim 1 as well as by a rotation angle measuring system having the features of claim 4.

[0007] In a method for initializing a rotation angle measurement system according to the present invention, after the rotation angle measurement system is mounted on a shaft to be detected, a predetermined initialization angular position of the rotor unit relative to a fixed stator unit of the rotation angle measurement system is set. The rotor unit is mounted to rotate with the shaft. Here, one initialization angular position can be predetermined. Alternatively, a plurality of initialization angular positions, generally substantially equally spaced, can be predetermined. The number of predetermined initialization angular positions preferably corresponds to the number of excitation magnets of the rotor unit. Preferably, the at least one initialization angular position is predetermined so that an excitation magnet of the rotor unit is positioned adjacent to the Wiegand multi-turn sensor at each initialization angular position. When there are a plurality of initialization angular positions, the predetermined initialization angular position closest in the direction of rotation of the shaft is typically set. The at least one initialization angular position can be determined by an initialization angular interval, in which case any angular position within the initialization angular interval constitutes the initialization angular position.

[0008] Once a predetermined initial angular position of the rotor unit relative to the stator unit is set, the relative rotation of the rotor unit relative to the stator unit is determined by the number of partial rotations (360° / N), where N=2. n The actual partial rotation counts, denoted by (n=1, 2, 3, ...), are read from the data storage device of the rotation angle measurement system where they are stored. The actual partial rotation counts represent the number of at least half a rotation (n=1), but may have a higher resolution than half a rotation, for example, the number of quarter rotations (n=2) or eighth rotations (n=3).

[0009] The read-out actual count values ​​of the partial rotations uniquely determine a real subinterval value. This real subinterval value indicates in which of the N (360° / N) subintervals the rotor unit is located relative to the stator unit throughout one complete rotation. Here, each subinterval encompasses an angular position range of (360° / N) degrees. Typically, the first (360° / N) subinterval encompasses an angular position range from 1° to (360 / N) degrees, and the second (360° / N) subinterval encompasses an angular position range from [(360 / N)+1]° to [2·(360 / N)]°.

[0010] In the present invention, the actual subinterval value is determined from the read-out partial-revolution actual count values ​​and compared with the target subinterval value assigned to each initialization angular position. Since the angular position of the rotor unit relative to the stator unit is uniquely known for each defined initialization angular position, a unique target subinterval value is also assigned to each defined initialization angular position. For example, when N=2, the actual subinterval value can be easily determined by evaluating one bit of the read-out partial-revolution actual count values, in particular by evaluating the last bit of the read-out partial-revolution actual count values. When the set initialization angular position is within the angular position range of the first (360° / N) subinterval, the target subinterval value indicates the first subinterval; when the set initialization angular position is within the angular position range of the second (360° / N) subinterval, the target subinterval value indicates the second subinterval, etc.

[0011] If the real subinterval value determined from the read-out actual partial revolution count value does not match the target subinterval value, a correction of the actual partial revolution count value stored in the data storage device is necessary. This correction is performed by increasing or decreasing the actual partial revolution count value stored in the data storage device so that the real subinterval value indicated by the actual partial revolution count value stored in the data storage device matches the target subinterval value. Typically, the actual partial revolution count value is incremented or decremented by a value X≦(N / 2). Within the meaning of the present invention, storing a partial revolution count offset that is added to or subtracted from the stored actual partial revolution count value when the stored actual partial revolution count value is read should be understood as incrementing or decrementing the actual partial revolution count value stored in the data storage device. If the real subinterval value determined from the read-out actual partial revolution count value matches the target subinterval value, the stored actual partial revolution count value remains unchanged.

[0012] The method for initializing a rotation angle measurement system according to the present invention ensures that, after initialization, actual count values ​​of a predetermined partial rotation, which indicate the correct partial section position of the rotor unit relative to the stator unit, are stored in a data storage device in a simple manner, thus enabling a simple and reliable initialization of the rotation angle measurement system.

[0013] Preferably, the rotational movement of the rotor unit relative to the stator unit is initiated to set a predetermined initialization angular position. This is typically done by driving the shaft. During the rotational movement, actual angular position values, which indicate the current relative angular position of the rotor unit relative to the stator unit, are determined (essentially continuously) by the single-turn sensor unit in a manner known in the art. The determined actual angular position values ​​are compared with at least one predetermined initialization angular position value, and each initialization angular position value is assigned to a unique predetermined initialization angular position. If the determined actual angular position value matches the predetermined initialization angular position value, the initialization angular position assigned to this initialization angular position value is considered to have been set, and the aforementioned method steps subsequent to setting the initialization angular position are executed. These subsequent processing steps can generally be performed very quickly, so it is not necessarily necessary to stop the rotational movement of the rotor unit when the initialization angular position is reached. This allows for a simple and reliable setting of the predetermined initialization angular position. If there are multiple predetermined initialization angular positions, automatically setting the predetermined initialization angular position closest in the direction of rotation minimizes the shaft rotations required to initialize the rotation angle measurement system.

[0014] As is known in the prior art, in Wiegand multi-turn sensors, so-called Wiegand pulses are generated by polarity changes in the excitation field generated by a permanent excitation magnet at the location of the Wiegand multi-turn sensor. The Wiegand pulses are detected by the Wiegand multi-turn sensor and evaluated, among other things, to determine the actual count value of a partial rotation. It is also known that so-called "runt" pulses occur in Wiegand multi-turn sensors. This applies if, after a previous change in direction of rotation, there are no Wiegand pulses generated by polarity changes in the excitation field that occur during the rotation of a permanent excitation magnet past the Wiegand multi-turn sensor, or if only Wiegand pulses with insufficient strength are generated to be detected.

[0015] Therefore, it is advantageous to read an actual pulse polarity value, indicating the polarity of the last Wiegand pulse generated by the Wiegand multi-turn sensor, from the data storage device after setting a specific initialization angular position and before checking the actual partial revolution count value. The read actual pulse polarity value is then compared with a target pulse polarity value assigned to the set initialization angular position. Preferably, at least one initialization angular position is predetermined so that a permanent magnet excitation magnet of the rotor unit is positioned adjacent to the Wiegand multi-turn sensor at each initialization angular position. As a result, the target pulse polarity value for each initialization angular position is clearly defined by the magnetic polarity of the excitation magnet positioned adjacent to the Wiegand multi-turn sensor at the initialization angular position, regardless of the direction of shaft rotation. If the read actual pulse polarity value does not match the target pulse polarity value for the specific initialization angular position, this indicates that a "runt" pulse has occurred. In this case, the actual partial revolution count value cannot be reliably checked and corrected, as described above. In this case, the rotor unit is then rotated in the direction of rotation to the next initialization angular position. If only one initialization angular position is preset, the rotor unit is then rotated one more revolution. Since two consecutive "runt" pulses are not possible if the direction of rotation is maintained, a non-"runt" Wiegand pulse is always generated when the rotor unit is rotated to the next initialization angle position. As a result, the actual count values ​​of the partial rotations can be reliably checked and, if necessary, corrected after the rotation. This allows for particularly reliable initialization of the rotation angle measurement system.

[0016] The rotation angle measurement system according to the present invention comprises a rotatable rotor unit designed to be mounted for rotation with a shaft, the rotor unit having an excitation magnet consisting of a plurality of permanent magnets, and a fixed stator unit having a Wiegand multi-turn sensor, a data storage device, and an evaluation unit.

[0017] The excitation magnets, consisting of permanent magnets of the rotor unit, are arranged along the circumference of the rotor unit such that at the location of the Wiegand multi-turn sensor, the polarity of the excitation field generated by the excitation magnet changes at least twice during one rotation of the rotor unit. Thus, during one complete rotation of the rotor unit, at least two Wiegand pulses are generated at the Wiegand multi-turn sensor, indicating the relative rotation of the rotor unit with respect to the stator unit (360° / N) number of partial rotations, N=2. n (n=1, 2, 3, ...) can be determined from the number of Wiegand pulses in a manner well known in the art. The rotor unit typically comprises a disk-shaped carrier that can be attached to a shaft, and a number of excitation magnets are attached to the carrier.

[0018] The rotation angle measurement system according to the present invention also comprises a single-turn sensor unit capable of detecting the angular position of the rotor unit relative to the stator unit. The single-turn sensor unit typically comprises a fixed sensor means assigned to the stator unit and a sensor means arranged on the rotor unit, which sensor means functionally interact with each other to detect the angular position of the rotor unit relative to the stator unit. The single-turn sensor unit can in principle be any single-turn sensor unit known in the prior art, which is capable of detecting the angular position of the rotor unit relative to the stator unit. The single-turn sensor unit can be, for example, a capacitive single-turn sensor unit, an optical single-turn sensor unit, or a mechanical single-turn sensor unit known in the prior art.

[0019] The data storage device can in principle be any data storage device known in the art and can consist of any number of volatile and / or non-volatile storage devices. Typically, a data storage device comprises at least one volatile storage device and one non-volatile storage device.

[0020] The evaluation unit is designed, as is known in the prior art, to determine an actual count of partial rotations, which indicates the relative rotation of the rotor unit with respect to the stator unit in number of (360° / N) partial rotations, and an actual angular position value, which indicates the relative angular position of the rotor unit with respect to the stator unit. The evaluation unit is also designed to store the determined actual count of partial rotations and the determined actual angular position value in a data storage device. The evaluation unit can in principle be composed of any number of components interacting with each other. As is known in the prior art, the evaluation unit can be composed, for example, of specific electrical circuits and / or of an integrated circuit or microcontroller programmed accordingly.

[0021] In the present invention, the rotation angle measurement system also includes an initialization unit having a predetermined target subinterval value, which is typically stored in a data storage device. The initialization unit according to the present invention is designed to read the actual partial rotation count values ​​from the data storage device and determine from the actual partial rotation count values ​​an actual subinterval value indicating which (360° / N) subinterval of one complete rotation the rotor unit is located in relative to the stator unit. The initialization unit according to the present invention is also designed to increment or decrement the actual partial rotation count values ​​stored in the data storage device when the actual subinterval value does not match the target subinterval value. Here, the actual partial rotation count values ​​are incremented or decremented so that the actual subinterval value indicated by the stored actual partial rotation measurement values ​​will later match the target subinterval value. Typically, the initialization unit according to the present invention is designed to increment or decrement the actual partial rotation count values ​​by a value X≦(N / 2). In the sense of the present invention, storing a partial revolution count offset, which is added to or subtracted from the stored actual partial revolution count when reading out the stored actual partial revolution count, is to be understood here as incrementing or decrementing the actual partial revolution count stored in the data storage device. The partial revolution count offset is then typically stored in a non-volatile storage device of the data storage device so that it remains available even after an interruption of the power supply to the rotation angle measurement system. The initialization unit is preferably constituted by an integrated circuit or a microcontroller programmed accordingly.

[0022] The initialization unit according to the invention makes it possible to carry out the above-mentioned method for initializing the rotation angle measurement system according to the invention, which method reliably stores in the data storage device, after initialization, actual count values ​​of predetermined partial revolutions that indicate the correct partial section position of the rotor unit relative to the stator unit. The initialization unit according to the invention thus provides a rotation angle measurement system that can be reliably and simply initialized.

[0023] The rotor unit preferably includes an excitation magnet consisting of at least four permanent magnets. As a result, the polarity of the excitation field generated by the excitation magnet at the Wiegand multi-turn sensor changes at least four times during one complete rotation of the rotor unit. Therefore, at least four Wiegand pulses are generated in the Wiegand multi-turn sensor during one complete rotation of the rotor unit. This allows for the determination of multiple initialization angle positions, so that the method for initializing the rotation angle measurement system according to the present invention can be performed with only relatively small rotations of the shaft. Furthermore, the presence of at least four excitation magnets allows for particularly reliable and accurate detection of the rotational movement of the shaft.

[0024] Advantageously, the rotor unit of the rotation angle measurement system is constituted by a first assembly and the stator unit of the rotation angle measurement system is constituted by a separate second assembly, and the first and second assemblies can be mounted on the shaft one after the other, which allows for easy mounting of the rotation angle measurement system on the shaft.

[0025] An embodiment of a rotation angle measurement system according to the present invention will be described below with reference to the accompanying drawings. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a cross-sectional view of a rotation angle measurement system according to the present invention. [Figure 2] FIG. 2 is a diagram showing a part of the stator unit of the rotation angle measurement system of FIG. [Figure 3] FIG. 3 is a top view of the rotor unit placed at the zero angle position of the rotation angle measurement device. [Figure 4] FIG. 4 shows the rotor unit of FIG. 3 in an initial angular position after installation of the rotation angle measurement system on the shaft, and shows the values ​​stored in the data storage device after installation. [Figure 5]FIG. 5 is a diagram showing the rotor unit of FIG. 3 rotated to an initialization angular position, showing values ​​stored in the data storage device after the rotation, and showing a flowchart of a method for initializing the rotation angle measurement system executed by the initialization unit of the rotation angle measurement system. DETAILED DESCRIPTION OF THE INVENTION

[0027] 1 shows a rotation angle measurement system 10 that detects rotational movement of a shaft 12. In this embodiment, the shaft 12 is a hollow shaft that extends substantially axially and is driven by a drive motor 14 having a fixed motor housing 16. The rotation angle measurement system 10 includes a rotor unit 18 and a stator unit 20. In this embodiment, the rotor unit is formed by a first assembly 19, and the stator unit 20 is formed by a second assembly 21, and the first assembly 19 and the second assembly 21 are sequentially attached to the shaft 12 when installing the rotation angle measurement system 10.

[0028] The rotor unit 18 includes a disk-shaped rotor circuit board 22 that radially surrounds the shaft 12 and is directly attached to the shaft 12. The rotor unit 18 is connected to the shaft 12 so as to rotate together with the shaft 12. Four excitation magnets 24a to 24d, each consisting of a permanent magnet, are arranged on the rotor circuit board 22. In this embodiment, the excitation magnets 24a to 24d are radially magnetized disk magnets, and are arranged so that their magnetization directions extend substantially parallel to the radial direction, i.e., so that their magnetic north poles N and magnetic south poles S are adjacent to each other in the radial direction. The excitation magnets 24a to 24d are particularly arranged so that adjacent excitation magnets 24a to 24d in the circumferential direction have opposite magnetization directions.

[0029] The stator unit 20 includes an annular stator circuit board 26 that radially surrounds the shaft 12. A Wiegand multi-turn sensor 28, a data storage device 32, and an integrated circuit 34 that forms an evaluation unit 36 ​​and an initialization unit 38 are arranged on the stator circuit board 26. In this embodiment, the stator unit 20 is attached to the motor housing 16 using a number of fastening means 40.

[0030] The Wiegand multi-turn sensor 28 is positioned so that the Wiegand wires 42 of the Wiegand multi-turn sensor 28 extend in the radial direction. By positioning the Wiegand multi-turn sensor 28 at substantially the same radial distance from the shaft 12 as the exciting magnets 24a-24d, the exciting magnetic fields generated by the exciting magnets 24a-24d can be reliably detected by the Wiegand multi-turn sensor 28.

[0031] The rotation angle measurement system 10 also includes a single-turn sensor unit 29. In this embodiment, the single-turn sensor unit 29 includes an optical single-turn sensor 30 disposed on the stator circuit board 26 and a code track (not shown) formed on the rotor unit 18 that is scanned by the single-turn sensor 30.

[0032] Four initialization angular position values ​​W1 to W4 are stored in the data storage device 32. In this embodiment, W1=45°, W2=135°, W3=225°, and W4=315°. Furthermore, for each initialization angular position value W1 to W4, target sub-interval values ​​HS1 to HS4 indicating in which (360° / N) sub-interval of one rotation relative to the stator unit 20 the rotor unit 18 is located. In this embodiment, N=2, and the target sub-interval values ​​HS1 to HS4 indicate whether the rotor unit 18 is located in the first half interval (HS=1: 0° to 180°) or the second half interval (HS=2: 180° to 360°) of one entire rotation relative to the stator unit 20 at each initialization angular position. Therefore, in this embodiment, HS1=HS2=1, and HS3=HS4=2. Furthermore, target pulse polarity values ​​PP1 to PP4, which indicate which polarity the last Wiegand pulse generated in the Wiegand multi-turn sensor 28 should have for each initialization angular position (PP=1: outer north pole of the exciting magnet, PP=2: outer south pole of the exciting magnet), are stored in the data storage device 32 for each initialization angular position value W1 to W4. Therefore, in this embodiment, PP1=PP3=2, and PP2=PP4=1.

[0033] The evaluation unit 36 ​​is connected to the Wiegand multi-turn sensor 28, the single-turn sensor 30, and the data storage device 32. The evaluation unit 36 ​​is designed to determine an actual partial-turn count value Un and an actual angular position value Wn by evaluating the sensor signals from the Wiegand multi-turn sensor 28 and the single-turn sensor 30. The actual partial-turn count value Un indicates the current number of partial turns (360° / N) of the relative rotation of the rotor unit 18 with respect to the stator unit 20, i.e., the current number of half turns, i.e., the number of half turns the shaft 12 has made. The actual angular position value Wn indicates the current angular position of the rotor unit 18 with respect to the stator unit 20. The evaluation unit 36 ​​is also designed to determine an actual pulse polarity value PPn, which indicates the polarity of the last non-runt Wiegand pulse generated by the Wiegand multi-turn sensor 28. The evaluation unit 36 ​​is also designed to store the determined actual partial revolution count values ​​Un, the determined actual angular position values ​​Wn and the determined actual pulse polarity values ​​PPn in the data storage device 32.

[0034] The initialization unit 38 can be activated as needed, for example by setting a corresponding bit switch in the data storage device 32 , to initialize the rotation angle measurement system 10 .

[0035] The initialization unit 38 is designed to set a predetermined initialization angular position. To this end, the initialization unit 38 is designed to read all the initialization angular position values ​​W1-W4 from the data storage device 32 and provide (directly or indirectly) a start signal to the drive motor 14 to initiate the rotational movement of the shaft 12, i.e., the rotor unit 18, relative to the stator unit 20. The initialization unit 38 is designed to substantially continuously read the actual angular position Wn from the data storage device 32 and compare it with the initialization angular position values ​​W1-W4. When the read actual angular position Wn matches the initialization angular position value W1-W4, the initialization unit 38 provides (directly or indirectly) a stop signal to the drive motor 14 to stop the rotational movement of the shaft 12, i.e., the rotor unit 18, relative to the stator unit 20.

[0036] The initialization unit 38 is also designed to perform a check for a "runt" pulse by retrieving the target pulse polarity values ​​P1-P4 and the actual pulse polarity values ​​PPn assigned to previously set initialization angular positions from the data storage device 32 and comparing the retrieved actual pulse polarity values ​​PPn with the retrieved target pulse polarity values ​​P1-P4.

[0037] The initialization unit 38 is also designed to set a next initialization angular position value W1-W4 when the actual pulse polarity value PPn does not match the read-out target pulse polarity values ​​P1-P4. To this end, the initialization unit 38 is designed, inter alia, to supply a start signal (directly or indirectly) to the drive motor 14 to start the rotational movement of the shaft 12, and to substantially continuously read out the actual angular position Wn from the data storage device 32, compare it with the initialization angular position values ​​W1-W4, and, if the read-out actual angular position Wn matches one of the determined initialization angular position values ​​W1-W4, to supply a stop signal (directly or indirectly) to the drive motor 14 to stop the rotational movement of the shaft 12.

[0038] The initialization unit 38 is also designed to check the partial rotation actual count value Un stored in the data storage device 32 and correct it if necessary. To this end, the initialization unit 38 is designed to read the partial rotation actual count value Un and the target sub-interval values ​​HS1 to HS4 assigned to the set initialization angle positions from the data storage device, and evaluate the read partial rotation actual count value Un to determine, from the partial rotation actual count value Un, a real sub-interval value HSn indicating which (360° / N) sub-interval of one complete rotation the rotor unit 18 is located in relative to the stator unit 20. Therefore, in this embodiment, the real sub-interval value HSn indicates whether the rotor unit 18 is located in the first half or the second half of one complete rotation relative to the stator unit 20. Here, the actual count value Un of an odd-numbered partial rotation has a real sub-interval value HSn=1 (first half interval), and the actual count value Un of an even-numbered partial rotation has a real sub-interval value HSn=2 (second half interval). The initialization unit 38 is also designed to compare the determined real subinterval value HSn with the read target subinterval values ​​HS1-HS4, and to increment the real count value U of the partial rotation stored in the data storage device 32 by a value X=N / 2=1 (corresponding to a half rotation) (or decrement by X=N / 2=1) if the determined real subinterval value HSn does not match the read target subinterval values ​​HS1-HS4.

[0039] FIG. 3 shows the rotor unit 18 in the zero angular position (Wn=0°) and indicates the individual values. An angle scale is depicted on the radial outside of the rotor unit 18. This allows the respective actual angular position value Wn to be determined for each rotational position of the rotor unit 18 by projecting the Wiegand wire drawing direction D of the fixed Wiegand multi-turn sensor 28 onto the (virtually rotated) angle scale. Furthermore, FIG. 3 shows four angular positions corresponding to the stored initialized angular position values ​​WS1-WS4, each with its own target subinterval value HS1-HS4 and its own target pulse polarity value PP1-PP4.

[0040] FIG. 4 shows the rotor unit 18 in an exemplary initial angular position after the rotation angle measurement system 10 has been attached to the shaft 12, with the actual angular position value Wn=283°, the actual partial rotation count value Un=11, and the actual pulse polarity value PPn=2 stored in the data storage device 32.

[0041] In the present invention, after the rotation angle measurement system 10 is attached to the shaft 12, the initialization unit 38 is activated to perform initialization of the rotation angle measurement system 10.

[0042] To set the initial angular position predetermined by the initial angular position values ​​W1-W4, the initialization unit 38 provides a start signal to the drive motor 14 to initiate the rotational movement of the shaft 12, i.e., the rotational movement of the rotor unit 18 in the clockwise direction relative to the stator unit 20. The evaluation unit 36 ​​substantially continuously determines and stores in the data storage device 32 the actual partial rotation count value Un, the actual angular position value Wn, and the actual pulse polarity value PPn during the rotational movement. The initialization unit 38 reads the actual angular position value Wn stored in the data storage device 32 and compares the read actual angular position value Wn with the initial angular position values ​​W1-W4 also read from the data storage device 32. If the read actual angular position value Wn matches one of the initial angular position values ​​W1-W4, the initialization unit 38 provides a stop signal to the drive motor 14 to stop the rotational movement of the shaft 12.

[0043] The initialization unit 38 starts with the actual angular position value Wn=283° shown in FIG. 4 as the initial angular position, and sets an initial angular position corresponding to the fourth initial angular position value W4=315° shown in FIG.

[0044] After setting the specified initialization angle position, the initialization unit 38 first reads out the actual pulse polarity value PPn from the data storage device 32, assigns the read out actual pulse polarity value PPn to each initialization angle position value W1 to W4 (here, W4), and compares it with the target pulse polarity values ​​PP1 to PP4 (here, PP4=1) read out from the data storage device 32.

[0045] Thus, in the described example, the read actual pulse polarity value PPn matches the target pulse polarity value PP4 of the set initialized angular position. If they do not match, the initialization unit 38 provides a start signal to the drive motor 14 to start the rotational movement of the shaft 12, and stops the rotational movement when the actual angular position value Wn read from the data storage device 32 again matches one of the initialized angular position values ​​W1-W4. In this case, the initialization unit 38 sets the next initialized angular position in the direction of rotation (here, W1).

[0046] Next, the initialization unit 38 reads the actual count value Un of the partial rotation (here, Un=11) from the data storage device 32, determines the actual sub-interval value HSn (here, HSn=1) from the read actual count value Un of the partial rotation, assigns the determined actual sub-interval value HSn to each of the initialized angular position values ​​W1 to W4 (here, W4), and compares it with the target sub-interval values ​​HS1 to HS4 (here, HS4=2) read from the data storage device 32.

[0047] Therefore, in the described example, the determined real subinterval value HSn does not match the target subinterval value HS4 of the set initialization angular position. Therefore, initialization unit 38 increments the partial rotation actual count value Un stored in data storage 32 by X=N / 2=1, i.e., by a value corresponding to one-half rotation. As a result, the partial rotation actual count value Un=12 is stored in data storage 32, resulting in a real subinterval value HSn=2.

[0048] After initialization according to the present invention, the actual sub-interval value HSn (here, HSn=2) determined from the actual count value Un (here, Un=12) of the partial rotation stored in the data storage device 32 eventually coincides with the target sub-interval values ​​HS1 to HS4 (here, HS4=2) corresponding to the set initialization angular position. [Explanation of symbols]

[0049] 10 Rotation angle measurement system 12 shafts 14 Drive motor 16 Motor housing 18 Rotor unit 19 First Assembly 20 Stator unit 21 Second Assembly 22 rotor circuit board 24a, 24b, 24c, 24d excitation magnet 26 Stator circuit board 28 Wiegand Multi-Turn Sensor 29 Single-turn Sensor Unit 30 Single-turn Sensors 32 Data storage device 34 Integrated Circuits 36 evaluation units 38 Initialization Unit 40 Fastening means 42 Wiegand Wire D Wiegand wire extension direction HS1, HS2, HS3, HS4 target subinterval values HSn real subinterval value N magnetic north pole PP1, PP2, PP3, PP4 Target pulse polarity values PPn Actual pulse polarity value S magnetic south pole Un actual count of partial rotation W1, W2, W3, W4 Initialized angle position value Wn Actual angle position value

Claims

1. A method for initializing a rotation angle measurement system (10), comprising the steps of: setting a predetermined initial angular position of the rotor unit (18) relative to the stator unit (20); reading an actual count (Un) of partial revolutions from a data storage device (32), the actual count (Un) indicating the relative rotation of the rotor unit (18) with respect to the stator unit (20) in (360° / N) partial revolutions (where N=2n (n=1, 2, 3, ...)); determining an actual sub-interval value (HSn) indicating in which (360° / N) sub-interval of a full rotation the rotor unit (18) is located relative to the stator unit (20) from the actual count value (Un) of the partial rotation; and incrementing or decrementing the partial rotation actual count value (Un) stored in the data storage device (32) when the real subinterval value (HSn) does not match the target subinterval value (HS1-HS4) assigned to the specified initialization angular position.

2. In the method for initializing the rotation angle measurement system (10), the step of setting the predetermined initialization angular position of the rotor unit (18) relative to the stator unit (20) comprises: Initiating rotational movement of the rotor unit (18) relative to the stator unit (20); determining an actual angular position value (Wn) indicative of the relative angular position of the rotor unit (18) with respect to the stator unit (20); and comparing the determined actual angular position value (Wn) with the initial angular position values ​​(W1-W4) assigned to the defined initial angular positions.

3. The method for initializing the rotation angle measurement system (10) comprises: After setting the predetermined initialization angular position, reading from the data storage device (32) a real pulse polarity value (PPn) indicating the polarity of the last Wiegand pulse generated in the Wiegand multi-turn sensor (28); The read actual pulse polarity value (PPn) is compared with the target pulse polarity values ​​(PP1 to PP4) assigned to the set initialization angle positions, 3. The method according to claim 1, wherein when the actual pulse polarity value (PPn) does not match the target pulse polarity value (PP1 to PP4) assigned to the set initialization angular position, the rotor unit (18) is rotated to a next initialization angular position.

4. A rotation angle measurement system (10) for detecting rotational movement of a shaft (12), comprising: a rotatable rotor unit (18) designed to be mounted to rotate with the shaft (12) and having excitation magnets (24a-24d) consisting of a plurality of permanent magnets; a fixed stator unit (20) having a Wiegand multi-turn sensor (28), a data storage device (32) and an evaluation unit (36); a single-turn sensor unit (29) capable of detecting the angular position of the rotor unit (18) relative to the stator unit (20); the evaluation unit (36) is connected to the Wiegand multi-turn sensor (28), the single-turn sensor unit (29) and the data storage device (32); the data storage device is designed to determine an actual count value (Un) of partial rotations indicating the relative rotation of the rotor unit (18) with respect to the stator unit (20) in terms of the number of (360° / N) partial rotations (where N=2n (n=1, 2, 3, ...)) and an actual angular position value (Wn) indicating the relative angular position of the rotor unit (18) with respect to the stator unit (20), and to store the determined actual count value (Un) of partial rotations and the determined actual angular position value (Wn) in the data storage device (32); An initialization unit (38) is provided to predetermine target subinterval values ​​(HS1-HS4), said initialization unit (38) comprising: Reading the actual count value (Un) of the partial rotation from the data storage device (32), determining an actual partial interval value (HSn) indicating in which (360° / N) partial interval of one rotation the rotor unit (18) is located relative to the stator unit (20) based on the actual count value (Un) of the partial rotation; A rotation angle measurement system (10) designed to increment or decrement the actual count value (Un) of the partial rotation stored in the data storage device (32) when the actual subinterval value (HSn) does not match the specified target subinterval value (HS1 to HS4).

5. 5. The rotation angle measurement system (10) according to claim 4, wherein the rotor unit (18) comprises an excitation magnet (24a to 24d) consisting of at least four permanent magnets.

6. 6. The rotation angle measurement system (10) according to claim 4 or 5, wherein the rotor unit (18) is constituted by a first assembly (19) and the stator unit (20) is constituted by a separate second assembly (21).

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