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EP-4735855-A1 - INDUCTIVE POSITION SENSOR

EP4735855A1EP 4735855 A1EP4735855 A1EP 4735855A1EP-4735855-A1

Abstract

A sensor (9) for sensing a rotation angle (22) of a shaft (7, 11) and a torque angle (16), which is dependent on a torque acting on the shaft (7, 11), wherein the shaft (7, 11) is divided into a first shaft section (11), a second shaft section (7) and a torsion element separating the first shaft section (11) and the second shaft section (7), comprising – a coarse track (18), which can be positioned circumferentially around the first shaft section (11) and comprises a coarse-track number, denoted hereafter by the formula symbol A, of coarse-track elements (29) arranged equidistantly in relation to one another; - a fine track (17), which can be positioned circumferentially around the second shaft section (7) and comprises a fine-track number, denoted hereafter by the formula symbol B and greater than the coarse-track number, of fine-track elements (27) arranged equidistantly in relation to one another; and - a sensing device (19), which is set up to sense the rotation angle (22) and the torque angle (16) from an angular position (34) of the coarse track (18) and an angular position (33) of the fine track (17) within a maximum torque-angle range, denoted hereafter by the formula symbol T, and a maximum rotation-angle range (51), denoted hereafter by the formula symbol S; - wherein the coarse-track number and the fine-track number are in a non-integer relationship to one another, characterized in that the coarse-track number and the fine-track number satisfy the following condition: formula (I), where the function gcd() stands for the determination of the greatest common divisor and the formula symbol Θ stands for the degree of a full angle.

Inventors

  • MUELLER, PETER

Assignees

  • Firma Bourns, Inc.
  • Mueller, Peter

Dates

Publication Date
20260506
Application Date
20240701

Claims (10)

  1. 1. Sensor (9) for detecting a rotation angle (22) of a shaft (7, 11) and a torque angle (16) which is dependent on a torque acting on the shaft (7, 11), wherein the shaft (7, 11) is divided into a first shaft section (11), a second shaft section (7) and a torsion element separating the first shaft section (11) and the second shaft section (7), comprising - a coarse track (18) which can be laid circumferentially around the first shaft section (11) and has a coarse track number of coarse track elements (29) arranged equidistant from one another, designated hereinafter by the formula symbol B; - a fine track (17) which can be laid circumferentially around the second shaft section (7) and has a fine track number of fine track elements (27) arranged equidistantly from one another, designated below with the formula symbol A, which is greater than the coarse track number; and - a detection device (19) which is designed to detect the angle of rotation (22) and the torque angle (16) from an angular position (34) of the coarse track (18) and an angular position (33) of the fine track (17) within a maximum torque angle range designated hereinafter by the formula symbol T and a maximum rotation angle range (51) designated hereinafter by the formula symbol S; - wherein the coarse track number and the fine track number are in a non-integer ratio to each other, characterized in that the coarse track number and the fine track number satisfy the following condition: where the function gcd() is used to determine the greatest common divisor and the symbol 0 is used to measure the degree of a full angle. 16 CORRECTED SHEET (RULE 91 ) ISA/EP
  2. 2. Sensor (9) according to claim 1, wherein the coarse track number and the fine track number have a common divisor.
  3. 3. Sensor (9) according to claim 1 or 2, wherein the coarse track (18) and the fine track (17) are designed to change an electrical and/or magnetic property of the space depending on their angular position (34, 33), and wherein the detection device (18) for detecting the angular position (34, 33) of the coarse track (18) or the fine track (17) is designed to generate an electrical coarse track signal (39) or fine track signal (40) dependent on the electrical and/or magnetic property of the space.
  4. 4. Sensor (9) according to claim 3, wherein the detection device (19) is set up to detect the coarse track signal (39) with an electrical coarse track signal error, designated below with the formula symbol E A , and the fine track signal (40) with an electrical fine track signal error, designated below with the formula symbol E B , and wherein the coarse track number and the fine track number are selected such that an error in the torque angle (16), designated below with the formula symbol E T , satisfies the following condition: where the formula symbol C can be any real value.
  5. 5. Sensor (9) according to one of the preceding claims, wherein the maximum angle of rotation range (51) is selected such that it satisfies the following condition: S=±19 - preferably S=±9.5 - - -. gcd(A,B) gcd(A,B)
  6. 6. Sensor (9) according to one of the preceding claims, wherein the maximum torque angle range (51) is selected such that it satisfies the following condition:
  7. 7. Sensor (9) according to one of the preceding claims, wherein the Coarse track number and fine track number is selected from: - A=9 and B=6, or - A=10 and B=6, or - A=12 and B=8, or - A=12 and B=9, or - A=15 and B=6, or - A=15 and B=10, or - A=18 and B=12.
  8. 8. Method for detecting a rotation angle (22) of a shaft (7, 11) with a sensor (9) according to one of the preceding claims, comprising: - detecting the angular position (34) of the coarse track (18); - detecting the angular position (33) of the fine track (17); - determining, based on the detected angular position (34) of the coarse track (18), a number of full periods (44) that the angular position (33) of the fine track (17) has already passed through; and - Correcting the angular position (33) of the fine track (17) based on the determined number of full periods (44) of the angular position (33) of the fine track (17).
  9. 9. The method according to claim 8, wherein the angular position (33) of the fine track (17) is added to the determined number of full periods (44) in order to correct the angular position (33) of the fine track (17).
  10. 10. Control device (19) for carrying out a method according to one of the preceding claims.

Description

INDUCTIVE POSITION SENSOR Description The present invention relates to a sensor for detecting a rotation angle of a shaft and a torque angle which is dependent on a torque acting on the shaft, a method using the sensor and a control device for carrying out the method. EP 1 081 454 A1 discloses an angle sensor with an oscillator circuit, several receiving coils and both a coarse track and a fine track in the form of movable inductive coupling elements. The angular position is evaluated by applying the Vernier algorithm, whereby the coarse and fine tracks must have different pitches. It is essential that the number of periodic repetitions of the elements of the coarse and fine tracks over the entire measuring range of the angle sensor are in a non-integer ratio to one another. However, no specific instructions for selecting the pitch are disclosed. The object of the invention is to improve the angle sensor. i REPLACEMENT BLADE (RULE 26) The problem is solved by the features of the independent claims. Preferred developments are the subject of the dependent claims. According to one aspect of the invention, a sensor for detecting a rotation angle of a shaft and a torque angle which is dependent on a torque acting on the shaft, wherein the shaft is divided into a first shaft section, a second shaft section and a torsion element separating the first shaft section and the second shaft section, - a coarse track which can be laid circumferentially around the first shaft section and has a coarse track number of equidistantly arranged coarse track elements, designated below by the symbol A; - a fine track that can be laid circumferentially around the second shaft section with a fine track number of fine track elements arranged equidistantly from one another, designated below with the symbol B, which is greater than the coarse track number; and - a detection device which is arranged to detect the angle of rotation and the torque angle from an angular position of the coarse track and an angular position of the fine track within a maximum torque angle range designated hereinafter by the formula symbol T and a maximum rotation angle range designated hereinafter by the formula symbol S; - wherein the coarse track number and the fine track number are in a non-integer ratio to each other, characterized in that the coarse track number and the fine track number satisfy the following condition: wherein the function gcd() for the Determination of the greatest common divisor and the formula symbol 0 stands for the degree measure of a full angle (360°). Based on the sensor mentioned at the beginning, the motivation behind the sensor is to measure torque integrate, but use both the coarse track and the fine track to determine the angle of rotation. Based on this motivation, the sensor specified is based on the preliminary consideration that in the case of a torque acting on the shaft, the coarse track and the fine track are adjusted relative to each other and thus distort the detection of the angular position. Algorithms already exist to correct this distortion, but these only work reliably if the torque acting on the shaft complies with an unknown torque angle limit. Here, the specified sensor attacks with the idea of bringing the coarse track and the fine track as close as possible to this torque angle limit, which is achieved with the inventive condition. In a further development of the specified sensor, the coarse track and the fine track are designed to change an electrical and/or magnetic property of the space depending on their relative angular position, and wherein the detection device for detecting the angular position of the coarse track or the fine track is designed to generate an electrical coarse track signal or fine track signal dependent on the electrical and/or magnetic property of the space. These signals can be further processed in a simple manner using information technology in order to determine both the torque with the aid of a spring hardness of the torsion element, which is assumed to be known because it can be freely selected, and the angle of rotation. In a further development of the specified sensor, the number of fine tracks and the number of coarse tracks have a common divisor. In this way, the maximum measurable torque angle can be maximized. In an additional development of the specified sensor, the detection device is designed to detect the coarse track signal with an electrical coarse track signal error, designated below with the formula symbol E A , and the fine track signal with an electrical fine track signal error, designated below with the formula symbol E B , and wherein the coarse track number and the fine track number are selected such that an error in the torque angle, designated below with the formula symbol E T , satisfies the following condition EE is sufficient: E f ~±(— +— +C), where the symbol C can be any real value for an AB. In this way, a buffer can be taken into account for measu