Method of determining axial displacement or axial position of shaft of electronic control device

Abstract

To provide a method of determining axial displacement or axial position of a shaft of an electronic control device.SOLUTION: The present invention concerns a method of determining axial displacement or axial position of a magnetized shaft, such as a setting stem (3) of a timepiece, of an electronic control device (1). The method is based on a new function which is obtained by multiplying the norm of the magnetic field generated by the magnetized shaft by a selected compensation function, which depends only on the rotation angle of the shaft in a plane orthogonal to the rotation axis of the shaft. A main advantage of introducing the compensation function is that it simplifies the processing of measurement and strongly minimizes necessary memory resources as there is no need to store a large number of different curves corresponding to different angular positions, and there is also no need to use directly the norm for determining the axial displacement / position. By applying the proposed method using the new function, it is possible to detect in a sufficiently precise manner the axial displacements / positions of the shaft, by using preferably a single magnetic sensor.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method for determining the axial displacement or axial position of a shaft of an electronic control device. The shaft may be, for example, the setting stem of a timepiece. The invention focuses on a magnetic crown stem associated with an electronic control module that includes a magnetometer, where the magnetic field of a magnet attached to the stem is measured to determine the axial position / displacement of the stem. The invention also relates to an apparatus configured to perform this method. [Background technology]

[0002] In the first type of electronic crown stem, the axial position of the stem is typically determined by electrical contacts that open and close at stable mechanical positions on the stem, designated T1, T2, and T3, where T1 refers to the rest position, T2 refers to the date-setting position, and T3 refers to the time-setting position. If the electronic control device enables the stem to also function as a pushbutton, an additional position, T0, is defined, which refers to the position where the crown is pressed and the stem is in contact with the end electrical contacts. These electrical contacts are mechanically actuated by a relatively complex number of components in contact with the stem.

[0003] In certain electronic control devices equipped with a magnet for detecting the rotation of a crown stem, the magnet forms a sliding part to maintain the axial position of the stem as it moves. The sliding part has a central hole with a square side, and the stem has at least a portion with a corresponding square cross section, which passes through the square hole, so that the magnet is rotated by the stem. The main drawback of this solution is that it requires as many electrical contacts as there are stable positions of the stem. The electrical contacts must not oxidize over time and must be able to withstand impacts. Furthermore, the number of mechanical parts is large, making their assembly relatively complex and expensive.

[0004] In the second type of electronic crown stem with a magnetic system, a magnet is attached to the stem and moves axially and rotationally with the stem. Detection of stem rotation is performed at position T1 using a magnetometer. Pressing the crown activates an end switch (position T0). In this way, the crown stem is used as a pusher, and when the switch is pressed, it can be determined that the crown stem is in position T0. Pressing the crown to activate the switch often results in unintentional rotation of the stem while its rotation is still being detected by the magnetometer. This unintentional rotation can be interpreted by the watch as an action (e.g., changing the selection in a displayed menu) that should be taken before pressing the switch (validating the entry of the selected item).

[0005] EP 3210083 describes a method for detecting the angular position of a magnet fixedly attached to a control stem, which is magnetized in the diametric direction. The detection of the magnet's axial position is only briefly mentioned and not explained. The method proposed in EP 3210083 is based on measuring three magnetic field components of the magnetic field generated by the magnet. The magnetic field vectors describe ellipses for different axial positions and complete rotations of the magnet, as illustrated in Figure 1. When these ellipses are projected onto a two-dimensional (2D) plane (XY), the resulting 2D curves remain elliptical, as illustrated in Figure 2. To accurately determine the angular position of the control stem, a circular curve is instead required in the XY plane. For this purpose, the magnetic field vectors are projected onto the two-dimensional (2D) plane XY by using a predetermined transformation matrix. However, as can be seen in Figure 3, for a preselected transformation matrix, the projections describe circles only for a given axial position of the magnet / stem. Projections for other axial positions describe ellipses. Although not mentioned in EP 3210083, the radii of the two circles used for detecting the axial displacement / position, as shown in Figure 3 of this patent document, can be assumed (the radii decrease as the rod, and therefore the magnet, moves away from the magnetic sensor / magnetometer). However, as mentioned above, the circles are obtained only for specific axial positions using a preselected transformation matrix. Therefore, at all other axial positions, first, there is an inaccuracy in detecting the value of the stem's rotation angle. Second, the length of the projected measured magnetic field vector also depends on the rotation angle, and therefore the axial position cannot be accurately determined. Such a vector describes an ellipse as the rotation angle changes over 360°. As a result, unless the axial position of the stem is known, the axial position of the stem cannot be accurately determined, and furthermore, the angular position of this stem cannot be accurately determined. Therefore, the method for determining the axial position proposed in document EP 3210083 is, first of all, unclear and lacks a detailed explanation.Furthermore, the teachings of this patent do not provide the skilled artisan with a means to efficiently and accurately measure the axial position of a magnet, particularly a dipole magnet, and therefore the stem. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] European Patent No. 3210083 [Patent Document 2] European Patent Application Publication No. 3705902 Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to overcome at least some of the above-mentioned drawbacks of existing solutions of magnetized control rods or shafts. It is therefore an object of the present invention to provide a solution for determining the axial displacement or axial position of a shaft of an electronic control device, such as a crown stem arrangement in a watch. [Means for solving the problem]

[0008] According to a first aspect of the present invention, there is provided a method for determining an axial displacement or axial position of a shaft of an electronic control device or a control value for a predetermined function or operation as a function of the axial displacement or axial position of the shaft, as set forth in claim 1.

[0009] The present invention has the advantage that the axial displacement or axial position of the crown stem (when the invention is applied to a wristwatch) can be detected with a relatively high degree of certainty without the use of electrical contacts and corresponding mechanical parts.

[0010] In certain modes, the present invention allows for the detection of the axial displacement or axial position of the shaft to be used to prevent or ignore detection of shaft rotation, to avoid unintended operation associated with shaft rotation, or to adjust the intensity of functions of the electronic watch.

[0011] Software implementation in a microcontroller or digital signal processor for determining the axial displacement or axial position of the stem is relatively straightforward. Furthermore, because most magnetometers have three measurement axes, these magnetometers can be used for determining axial displacement in accordance with the present invention without incurring additional cost by simply adding a sensor dedicated to measuring axial displacement.

[0012] According to a second aspect of the present invention there is provided an electronic control module for determining the axial displacement or axial position of a shaft of an electronic control device, as set out in claim 12. According to a third aspect of the present invention there is provided a timepiece comprising an electronic control module. Further aspects of the present invention are set out in the dependent claims attached hereto. [Effects of the Invention]

[0013] Other features and advantages of the invention will become apparent from the following description of non-limiting exemplary embodiments, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0014] [Figure 1] As already explained, Figure 1 illustrates the measurement of the 3D components of the magnetic field as a function of the rotation angle and the axial position of a bipolar magnet with a diametrical magnetization axis (two diametrically opposed poles) according to EP 3210083. [Figure 2] FIG. 2, as already explained, illustrates the measurement of the 2D components of the magnetic field as a function of the rotation angle of a dipole magnet and the axial position of this magnet according to EP 3210083. [Figure 3] FIG. 3, as already explained, illustrates the 2D components of the magnetic field projected onto the XY plane as a function of the rotation angle of a dipole magnet and the axial position of this magnet, by using a transformation matrix to have a circle at z=0.0 in this plane, according to EP 3210083. [Figure 4] FIG. 4 is an isometric view illustrating an example of an electronic control device according to the present invention. [Figure 5] FIG. 5 is a diagram illustrating the value of the component x of the magnetic field as a function of the rotation angle of the setting stem and the axial displacement / position of this setting stem in the electronic control device of FIG. [Figure 6] FIG. 6 is a diagram illustrating the value of the component y of the magnetic field as a function of the rotation angle of the setting stem and the axial displacement / position of this setting stem in the electronic control device of FIG. [Figure 7] FIG. 7 is a diagram illustrating the value of the component z of the magnetic field as a function of the rotation angle of the setting stem and the axial displacement / position of this setting stem in the electronic control device of FIG. [Figure 8] FIG. 8 is a diagram illustrating the value of the norm of the magnetic field as a function of the axial displacement / position of the setting stem and the angle of rotation in the electronic control device of FIG. [Figure 9] FIG. 9 is a diagram illustrating compensation functions, each dependent on the rotation angle of the setting stem, that compensate for the dependence of the magnetic field norm on the rotation angle for three different axial positions. [Figure 10] FIG. 10 is a diagram illustrating the values of the function G(z,θ) equal to the magnetic field norm multiplied by a single selected compensation function used in the first mode of the present invention to select the relationship between the possible values of these functions and the corresponding axial displacement / position of the setting stem for all possible rotation angles of the setting stem in the electronic control device of FIG. [Figure 11]FIG. 11 is a diagram illustrating the values of the function G(z,θ) equal to the magnetic field norm multiplied by another single selected compensation function used in a second mode of the present invention to select the relationship between the possible values of these functions and the corresponding axial displacement / position of the setting stem for all possible angles of rotation of this setting stem in the electronic control device of FIG. [Figure 12] Figure 12 is a flow chart summarizing the steps of the proposed method. DETAILED DESCRIPTION OF THE INVENTION

[0015] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The present invention will be described in the context of detecting the axial displacement or axial position of a shaft of an electronic control device of a timepiece, which in this example is a setting stem associated with an external crown of the electronic control device. The electronic control device described below comprises at least a crown, a setting stem, a magnetic element integrally attached to the stem, and an electronic control module formed by a magnetometer and a signal processor. In this configuration, a magnetic field is generated by the magnetic element of the rotating stem. However, the teachings of the present invention are not limited to this environment or application.

[0016] Identical or corresponding functional and structural elements that appear in different drawings are assigned the same reference numerals. As used herein, "and / or" means one or more of the items in the list joined by "and / or." As an example, "x and / or y" means any element from the three-element set {(x), (y), (x,y)}. In other words, "x and / or y" means "one or both of x and y." As another example, "x, y and / or z" means any element from the seven-element set {(x), (y), (z), (x,y), (x,z), (y,z), (x,y,z)}. In other words, "x and / or y" means "one or more of x, y, and z." Furthermore, the term "comprising" is used herein as an open-ended term. This means that an object encompasses all listed elements but may also include additional, unnamed elements. Accordingly, the term "comprises" is to be interpreted in its broader sense as including, incorporating, or encompassing.

[0017] In this description, a magnetic field is a vector field that represents the magnetic effects of electric currents and magnetized materials. The term "magnetic field" is sometimes used for two different but closely related fields, denoted by the symbols B and H. H is measured in units of amperes per meter, while B is measured in tesla, which is equal to newtons per meter per ampere. H and B differ in their methods of magnetization. In a vacuum, B and H are the same except for their units, but in a magnetized material, they differ depending on the magnetization M of the material. In the following description, the magnetic field will be expressed as B, but H can be used interchangeably.

[0018] FIG. 4 illustrates an example of an electronic control device 1 to which the teachings of the present invention can be applied. A rotatable element or shaft 3 is shown, which in this example is a setting stem of a timepiece such as a wristwatch. The stem 3 defines a rotation axis 5 that coincides with the central or longitudinal axis of the stem 3. Such a setting stem is also known as a crown stem. Thus, the rotatable element 3 (i.e., the stem) in this example is a small, elongated piece with a diameter, for example, in the range of 0.5 mm to 1 mm. The stem 3 is provided with a magnet 7 in its internal end region (i.e., at the end of the setting stem that is located inside the timepiece case, opposite the crown, if the setting stem terminates in the crown) assembled with the stem for rotation and axial displacement therewith. In this example, the magnet is configured as a ring through which the stem passes. The magnet 7 is preferably a diametrically magnetized bipolar permanent magnet with two magnetic poles diametrically opposed relative to the rotation axis 5 and will be referred to hereinafter as a "bipolar magnet" or simply as a "magnet."

[0019] The stem 3, and therefore the magnet 7, has only two degrees of freedom: one degree of rotation relative to the axis of rotation 5, and the other degree of translation along this axis of rotation 5. The angle of rotation of the magnet, and therefore of the stem, is indicated by θ, and the axial displacement / position of the magnet, and therefore of the stem, along the axis of rotation is indicated by z.

[0020] The magnetometer 9, mounted on a circuit board 11, in particular a printed circuit board (PCB), measures the magnetic induction field of the magnet along three orthogonal axes X, Y and Z, and defines a reference frame for this magnetometer, B x ,B y and B zThe Z axis is parallel to the axis of rotation 5 of the stem and therefore of the magnet, and therefore the plane XY is perpendicular to the axis of rotation 5. In this example, the centre of the magnetometer at the origin of the reference frame defines the zero position (z=0) of the dipole magnet 7 and therefore of the stem along the axis of rotation, i.e., crossing the XY plane by the axis of rotation 5 defines the zero axial position (z=0) of the magnet and therefore of the stem 3. In this example, an optional switch 13 is also provided, which is used to selectively enable or disable the magnetometer and / or to activate selected functions of the timepiece.

[0021] The magnetic field lines generated by magnet 7 impinge on magnetometer 9, which is a three-axis sensor device that measures the incident magnetic field along three measurement axes: X-axis, Y-axis, and Z-axis. Magnetometer 9 can be, for example, a small surface mounted device (SMD) mounted on PCB 11 and connected to the PCB via an SMD connection.

[0022] In this example, magnetometer 9 is a Hall effect sensor device, which is a device used to measure the magnitude or strength of a magnetic field. The output voltage of a Hall sensor is directly proportional to the strength of the magnetic field passing through it. Magnetometer 9 measures a first magnetic field component B along a first axis, which in this case is the X axis. x and the strength of the second magnetic field component B along a second axis, in this case the Y axis. y and a third magnetic field component B along a third axis, in this case the Z axis. z and the intensity of the magnetic field component B. In this example, these three axes are orthogonal to one another. To measure the temperature, a temperature sensor (not shown in the figure) may additionally be provided. If provided, the temperature sensor may for example be integrated into the magnetometer 9. The behavior of the Hall sensor usually depends on the operating temperature. Instead of the system comprising one three-axis magnetometer, for example, three sensors may be provided, each measuring the magnetic field component B x ,B y and B zIt should be noted that the present invention may include three independent magnetic field sensors configured to measure different magnetic field components of the three sensors, in which case all three sensors may or may not be in the same plane.

[0023] According to the invention, the method for determining the axial displacement or axial position of the magnet 7, and therefore of the stem 3, along the axis of rotation 5 is carried out by measuring the component B of the magnetic induction field. x ,B y and B z These magnetic field components not only depend on the rotation angle θ of the dipole magnet, but also on the position of this magnet along the axis of rotation 5, which is parallel to the Z axis but away from the axis of rotation. It should be noted that the symbol θ is used interchangeably in this description for both the rotation angle of the magnetic field (and therefore of the magnet 7) and the rotation angle of the stem 3. The magnetic field components B as a function of the rotation angle θ of the magnet x ,B y and B z The values of can be seen in Figures 5, 6 and 7 for three different axial displacements / positions: z=0.0 mm, z=0.5 mm and z=1.0 mm, respectively. The magnetic field components are compensated for hard iron coefficients to eliminate effects due to parasitic magnetic fields and possibly temperature variations. In other words, the main effects of the compensation are: to eliminate offsets due to the manufacturing of the Hall sensors, to eliminate distortions due to the presence of parasitic magnetic fields, especially those generated by the circuit board hosting the magnetometer, and also somehow to eliminate temperature effects. Figures 5, 6 and 7 illustrate the values of the compensated magnetic field components.

[0024] These components taken individually are insufficient to detect the axial displacement or axial position of the magnet. z has two zero crossings per magnet revolution. However, if we consider the norm of the magnetic field (Euclidean norm in this example), we get:

[0025] JPEG2025115942000002.jpg18170

[0026] An interesting behavior is obtained in that the value decreases as the magnet 7 moves away from the magnetometer 9 along the axis of rotation. Furthermore, the norm never reaches zero. This is illustrated in Figure 8. In practice, to save calculations, the square root is often not calculated and the square of the norm is used. However, in this example, the norm is calculated and used.

[0027] In Figure 8, it can be seen that the value of the norm depends not only on the axial displacement / position but also on the rotation angle θ. To avoid or minimize this angular dependence, the method introduces a first function F(θ), also referred to as a compensation function, that depends only on the rotation angle / angular position θ. In other words, the value of the selected compensation function does not depend on the axial displacement / position. The compensation function is selected such that the norm of the magnetic field, when multiplied by the compensation function, results in a second function G(z,θ) that depends heavily on the axial position of the shaft (stem) and is less or not dependent on the rotation angle of the shaft.

[0028] JPEG2025115942000003.jpg13170

[0029] This second function G(z,θ) is plotted along the axis of rotation 5 (z is used as the variable along the axis of rotation parallel to the Z axis) in FIGS. 10 and 11, respectively, for two different specific compensation functions, which show the lower and upper curves defined by the second function G(z,θ) for all angular positions θ, i.e., the envelope of all possible curves of G(z,θ) resulting from the dependence of this second function on the angular position θ. These two different specific compensation functions will be further explained later in this description. It can be seen in these figures that the variance of the second function G(z,θ) for all rotation angles / angular positions is much smaller than the variance of the corresponding norm.

[0030] The method continues with a second function G(z,θ), because it allows the axial displacement or position z of the magnet 7 / stem 3 to be determined with sufficient accuracy for multiple applications by simply selecting one specific compensation function F(θ) (named "compensation function") for each specific application. The main advantage of introducing a compensation function is that it simplifies the measurement process and significantly minimizes the memory resource requirements, since it is not necessary to store many different curves corresponding to different rotation angles / angular positions, nor is it required to directly use the norm to determine the axial displacement / position (see FIG. 8).

[0031] The preferred individual compensation function F z (θ) is plotted in FIG. 9 for axial position z from 0.0 mm (the individual compensation function with the largest amplitude) to 1.0 mm (the individual compensation function with the smallest amplitude), where it can be seen that these individual compensation functions are somewhat dependent on axial position. Between the two extreme compensation functions (corresponding to z=0.0 mm and z=1.0 mm, respectively), for a given position range from 0.0 mm to 1.0 mm, for each angular position, there is a specific compensation function F that corresponds to the mean / median of all the individual compensation functions over axial position z. m (θ) is expressed. Therefore, the function F m (θ) corresponds to either the mean or median compensation function.

[0032] All preferred individual compensation functions are based on a general compensation function F that depends on the axial position z and the angular position θ. G It is defined by (z,θ).

[0033] JPEG2025115942000004.jpg15170

[0034] However, by definition, the axial position is unknown before performing this method, which is actually implemented to determine the axial displacement / position of the magnet / stem. Therefore, the method of the present invention uses two extreme compensation functions F (z=0.0 mm and z=1.0 mm). z9 (where θ is the general compensation function F θ ) and all other general compensation functions are in between. G A single specific compensation function F(θ) is selected based advantageously on (z, θ).

[0035] A single specific compensation function (termed "compensation function"), i.e., its amplitude, is specific to each electronic control device of the present invention. According to a preferred implementation of the present invention, a single specific compensation function F(θ) is selected in relation to the application in which the axial displacement / position determination method is implemented. For example, if the method is used to detect individual axial displacements / positions of the stem according to a first mode, such as stable positions T1, T2, and T3, then the average / median compensation function F(θ) is selected. m (θ) can be advantageously chosen such that the compensation function is:

[0036] Mean or median across z of JPEG2025115942000005.jpg24121

[0037] This means that in the first mode, the mean or median value (shown as a solid line in FIG. 9) is adopted to minimize the deviation with angular position over the entire displacement / position range (z=0.0-1.0 mm) of the corresponding second function G(z,θ), as can be seen in FIG. 10. In this FIG. 10, the mean / median compensation function F(θ) is used for the compensation function F(θ). m By selecting (θ), curve UC1 becomes the upper limit and curve LC1 becomes the lower limit of the second function G(z,θ) as a function of axial position z. Based on these upper limit curve UC1 and lower limit curve LC1, the method establishes / selects a relationship between the value g of G(z,θ) and the axial position z based on all angular positions θ. In general, the method selects a relationship between a first set of possible second values and a second set of possible axial displacements, or for each second value of the first set, a corresponding axial displacement or axial position of the shaft, or a corresponding range of axial displacements or positions of the shaft, or a corresponding control value.

[0038] In the example provided in FIG. 10 , three position ranges R1, R2, and R3 are defined for positive values of the stem's axial position z around three corresponding, distinct, stable axial positions T1, T2, and T3 that the stem can have. The position ranges R1, R2, and R3 are selected to cover all possible positions for each axial position T1, T2, and T3 without overlapping, with sufficient margin to account for manufacturing tolerances of the various elements forming the electronic control device and tolerances resulting from the assembly of these elements. It should be noted that for each, the range Rn,n=1,2,3 corresponds to the range Pn,n=1,2,3, which comprises all possible values g of the second function G(z,θ) for this range Rn. Conversely, the ranges Rn,n=1,2,3 do not include all possible values z of the respective range Pn of G(z,θ). The selected relationship advantageously defines distinct, non-overlapping ranges Pn of g values for corresponding axial position ranges Rn of axial positions. In other words, the ranges of second values Pn are distinct so that they do not overlap with one another, as shown in Figure 10. Thus, for any possible second value, there is only one position range Rn and corresponding axial position Tn.

[0039] On the other hand, if the displacement / position determination method is used to detect the axial displacement of the stem 3, for example, in terms of position T0 from position T1, a different compensation function can be selected according to the second mode to disable the determination of the rotation angle of the stem 3 or to ignore the determination of the rotation angle of the stem 3 when the stem is pressed by the user. This type of operation is particularly useful if, in a given position of the stem (usually the non-pressed position of the stem), rotating the stem displays a different menu, while in a second position of the stem (usually the pressed position of the stem), pressing the stem is used, for example, to select a given function or enter a menu. In this example, if the user presses the stem, they may accidentally rotate it at the same time, which would display a different menu unless the rotation detection is disabled or ignored. In this scenario, the compensation function F(θ) is defined as follows, where it more accurately takes the value z=P at the start of the displacement from the axial position P so that the pressing of the stem can be determined at an early stage:

[0040] JPEG2025115942000006.jpg21170

[0041] If the pressing force is intended from the axial position T1 (near z=0), z=0 is introduced into the above compensation function as shown in Figure 11. For the compensation function F(θ), the compensation function F for P=0 is P By selecting (θ), the upper limit of the second function G(z,θ) as a function of the axial position z is the curve UC2, and the lower limit is the curve LC2. Th A threshold g can be selected below which the detection of stem rotation should no longer be considered. This is illustrated in Figure 11, where negative position values along the axis of rotation are shown. In other words, the threshold g Th is defined for G(z,θ), and the method comprises disabling or ignoring the determination of the rotation angle of the shaft / stem 3 if the value g of G(z,θ) is less than or equal to a threshold value.

[0042] Thus, as explained, the compensation function can be advantageously tailored depending on the use case or application of the displacement or position determination method.

[0043] Once the compensation function F(θ) has been selected and the current rotation angle θ of the stem has been measured, the value of the second function G(z,θ) can be calculated. It should be noted that the rotation angle can be measured or determined according to the teachings of EP 3705902. As explained in EP 3705902, the value of the current rotation angle of the stem in a plane perpendicular to the axis of rotation of the shaft is calculated by dividing the two magnetic field components perpendicular to the axis of rotation, namely component B x ,B y Then, when the current rotation angle θc is first applied to the compensation function F(θ), the norm N of the measured magnetic field is calculated. c The compensation function value g c The value of G(z,θ) can be calculated by multiplying

[0044] The compensation function is chosen so that the value g of G(z,θ) depends primarily on the axial position z of the shaft and relatively little or no dependence on the rotational angle θ of the shaft. The upper and lower curves represent the uncertainty of any value g with respect to the axial displacement / position.

[0045] In summary, when using the proposed method to detect stable mechanical positions such as positions T1, T2 and / or T3 (first mode), a set of non-overlapping ranges of values P1, P2 and P3 of the second function G(z,θ) corresponding to these stable positions of the stem including possible errors / misalignments can be defined, as further illustrated in Figure 10. When preventing rotation detection (second mode), a threshold g of G(z,θ) can be defined. Th and angle values below this threshold should not be considered. This is illustrated in FIG.

[0046] The flowchart of Figure 12 summarizes the above method for determining the axial displacement or axial position of an at least partially magnetized stem of an electronic control device. In step 101, first, second, and third magnetic field components, in this case orthogonal to each other, are measured by magnetometer 9. This step typically comprises compensating the magnetic field components to take into account hardening iron factors. In step 102, the current rotation angle value θ of stem 3 in a plane orthogonal to rotation axis 5 is measured. c (current angular position) is determined based on at least two of the magnetic field components orthogonal to the axis of rotation. In step 103, the current norm N is calculated as a squared or non-squared value of the magnetic field based on the first, second, and third magnetic field components. c , JPEG2025115942000007.jpg1351 is calculated. The norm depends on the axial displacement of the shaft along the axis of rotation and the angle of rotation of the shaft.

[0047] In step 104, a first function F(θ), referred to as a compensation function, is selected for at least the mode / application, e.g., the first and second modes previously described, in which case an appropriate function is selected for the current mode (detection of an axial position from a set of possible stable axial positions, or detection of activation of a push button function). The selected compensation function depends on the rotation angle of the shaft, but is independent of the axial displacement of the shaft. In step 105, the value of the current rotation angle is calculated based on the selected compensation function V(θ). c =F(θ c ) to obtain a first value V, referred to as the compensation function value. c is the current rotation angle value θ c The obtained value V c is stored in the memory of the electronic crown module.

[0048] In step 106, the calculated magnetic field norm and the determined compensation function value g c =N c ·V c. and the second value of the second function previously described is calculated. According to the invention, the compensation function is selected so that the second function depends primarily on the axial position of the shaft and relatively little or no dependence on the rotation angle of the shaft. In particular, the compensation function is selected so that the bundle of the second function G(z,θ) is sufficiently narrow, as illustrated, for example, in FIGS. 10 and 11, so that G(z,θ) provides a relatively good approximation of the axial position z for all θ and thus allows the position z to be determined with a relatively low margin of error, in particular to unambiguously distinguish between predetermined different positions (T1, T2, T3) or to determine the position z within a certain threshold D. Th , which allows for determining whether a function has been pressed beyond the threshold g to activate the function, or to prevent accidental selection of a function in a menu by, for example, rotating the stem. In practice, the invention relies on extreme curves, i.e., upper and lower curves, for positions T1, T2 and T3 with a margin of error. For pressure detection, the invention generally relies on the lower curve, and a predetermined threshold g Th For values of g less than , the stem is at the corresponding quantile value D given by this lower curve. Th It can only be concluded that it is at least being pressed.

[0049] In step 107, a relationship between the first set of possible second values and the second set of possible axial displacements or axial positions and / or control values is selected to establish, for each second value of the first set, a corresponding axial displacement or axial position of the shaft, or a corresponding range of axial displacements or positions of the shaft, or a corresponding control value. The control value is related to the adjustment of the function or operation of the timer. More specifically, the control value in this example can provide an intensity adjustment of the function of the timer depending on the axial displacement or axial position of the shaft. It should be noted that the second function G(z) is not used directly, but rather simply uses the range defined by the lower and upper curves (envelopes), i.e., g → Rz, where Rz is the range of possible axial positions for a given value g of the second function G(z). In this way, a relationship between g and z is selected, but is not necessarily a function that, by definition, gives a single z value for each g. Furthermore, in the case of a mode linked to pressure detection, for stems with at least a constant displacement, the algorithm calculates the obtained g c Instead of determining the axial displacement z from the value of g c The algorithm directly determines the command of the function based on z. There is an implicit link with the axial position of the stem, but in this case the algorithm works as if there is no specific step of determining the axial displacement z before the action.

[0050] In step 108, the calculated second value g c to the selected relationship between the first and second sets, the axial displacement or axial position z of the shaft relative to the sensor arrangement (9) c , or a control value is determined.

[0051] The data processing steps of the methods described above may be performed by a digital signal processor (DSP) and are therefore computer-implemented processing steps. The DSP may be part of the magnetometer or may be a stand-alone device. The DSP may also comprise memory, or a stand-alone memory unit may be used, for example, to store different functions and measurements.

[0052] The solution proposed by the present invention allows the axial displacement or axial position of the stem to be detected in an analog manner without electrical contacts. When the magnetometer 9 and angle-determining algorithm operate during stem 3 movement, the crown angle, and thus the axial position, can be known with sufficient precision to unambiguously determine a specific axial position or range of axial positions, determined using a single electronic component configured to perform the necessary calculations. Adjustment positions T1, T2, and T3 (in the first mode) can then be detected, particularly by eliminating the mechanical complexity of electrical contacts. Regarding the second mode, when the crown is pressed to reach T0 to activate an operation or enter a menu, a slight rotation of the crown can produce an increment of angle sufficient to cause an unintended change of the watch's menu. By monitoring the axial position of the crown according to the method of the present invention, rotation detection can be blocked or ignored once a predetermined axial displacement or axial position value is reached, avoiding unintended menu changes.

[0053] Considering the above, at least the following use cases are possible application scenarios of the present invention: detection of different positions of the stem (e.g. T1 to T3) according to a first mode, blocking or ignoring angle detection during axial movement of the stem, especially when selecting a function (menu) by pressing the crown (second mode 2), and intensity adjustment of an electronic watch function (third mode). The intensity adjustment function could involve moving the watch hands slower or faster when setting the time, or could serve as an interface for a game, for example.

[0054] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive, and the invention is not limited to the disclosed embodiments. Other embodiments and variations can be understood and effected by those skilled in the art in practicing the claimed invention, based on the drawings, the disclosure, and the appended claims.

[0055] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. The mere fact that different features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be used to advantage. Reference signs in the claims are not to be construed as limiting the scope of the invention. [Explanation of symbols]

[0056] 1. Electronic Control Devices 3 Stem, shaft 5 Displacement axis, rotation axis 7 Magnets, permanently magnetized parts, bipolar magnets 9 Magnetic sensor arrangement, magnetometer 11 Circuit Board 13 Switch

Claims

1. A method for determining an axial displacement or axial position along a displacement axis (5) of a shaft (3) comprising a permanently magnetized portion (7) and rotating about said displacement axis, or a control value of a predetermined function or operation as a function of said axial displacement or axial position of said shaft, by means of a magnetic sensor arrangement (9) and a processing unit collectively forming an electronic control module, said method comprising the following steps executed by said electronic control module: - measuring (101) using said magnetic sensor arrangement first, second and third field components of the magnetic field generated by said permanently magnetized portion along orthogonal first, second and third axes linked to said magnetic sensor arrangement, respectively, and along a third axis parallel to said displacement axis, and compensating said first, second and third field components for a hardening iron coefficient; - based on the compensated first and second magnetic field components, the value of the current rotation angle (θ) of the shaft (3) in a plane perpendicular to the displacement axis (5) of the shaft (3); ｃ ) (102); based on the compensated first, second and third magnetic field components, the norm of the magnetic field (N ｃ ) as a squared or non-squared norm, said norm depending on the axial position of the shaft along the displacement axis (5) and on the rotation angle of the shaft (3); a step (104) of selecting a compensation function F(θ) that depends on the angle of rotation (θ) of the shaft (3) but that is independent of the axial displacement or axial position (z) of the shaft; - the current rotation angle value (θ ｃ ) to the compensation function to obtain a first value (V ｃ ) (105), the calculated norm of the magnetic field (N ｃ ) and the determined compensation function value (V ｃ ) to obtain a second value (g ｃ ) wherein the compensation function is selected such that the second value depends primarily on the axial position of the shaft and less or not on the rotation angle of the shaft; - selecting (107) a relationship between a first set of possible second values and a second set of possible axial displacements or axial positions or / and control values as a function of said possible axial displacements or axial positions, and establishing for each second value of said first set a corresponding axial displacement or axial position of said shaft, or a corresponding range of axial displacements or axial positions of said shaft, or a corresponding control value; - the calculated second value (g ｃ and determining (108) the axial displacement or axial position of the shaft relative to the magnetic sensor arrangement (9), or the control value, by applying a set of the selected relationships between the first set and the second set.

2. 2. The method of claim 1, wherein the step of selecting a relationship between the first set and the second set establishes a corresponding range of second values for each possible stable axial position of the shaft.

3. The method of claim 2 , wherein the second range of values is distinct such that the second range of values does not overlap with other ranges.

4. The step of selecting the relationship may include determining a threshold value (g Ｔｈ 2. The method of claim 1, further comprising the step of defining a second value of the axial displacement or the axial position or the control value, and wherein the step of determining the axial displacement or the axial position or the control value comprises the step of disabling or ignoring the determination of the rotation angle of the shaft (3) if the second value is less than or equal to the threshold value.

5. 2. The method of claim 1, wherein the control value in the step of selecting the relationship provides an intensity adjustment depending on the axial displacement or axial position of the shaft for a function of a timepiece incorporating an electronic control device comprising the shaft and the electronic control module.

6. 6. The method of claim 1, wherein the compensation function is selected based on how the axial displacement or position of the shaft is to be used.

7. The compensation function F(θ) is where z denotes the axial displacement or axial position of the shaft (3) along the axis of rotation (5) and θ denotes the angle of rotation of the shaft (3) in a plane perpendicular to the axis of rotation (5), The method of claim 2 or claim 3, wherein denotes the magnetic field.

8. The compensation function F(θ) is where θ denotes the angle of rotation of the shaft (3) in a plane perpendicular to the axis of rotation (5), and z=P denotes a predetermined axial displacement or axial position along the axis of rotation (5) of the shaft (3) at which an axial displacement is detected; The method of claim 4 , wherein denotes the magnetic field.

9. The method of claim 8 , wherein the axial position P=0.

10. 10. The method according to any one of claims 1 to 5, 8 and 9, wherein the magnetic sensor arrangement is a three-axis magnetometer (9) or is formed by three sensors, each configured to determine a different one of the magnetic field components.

11. 10. The method according to any one of claims 1 to 5, 8 and 9, wherein the electronic control module is integrated into a timepiece, the shaft (3) is a setting stem associated with a crown of the timepiece, and the permanently magnetized portion of the shaft is a diametrically magnetized bipolar magnet fixed to the shaft.

12. 1. An electronic control device (1) for determining an axial displacement or axial position of a shaft (3) along a displacement axis (5) or a control value of a predetermined function or operation as a function of said axial displacement or axial position of said shaft, said shaft being provided with a permanently magnetized portion (7) and configured to rotate about said displacement axis, said electronic control device comprising a control module with a magnetic sensor arrangement (9) and a processing unit, said electronic control module comprising: - measuring, using said magnetic sensor arrangement (9), first, second and third magnetic field components of the magnetic field generated by said permanently magnetized portion along orthogonal first, second and third axes linked to said magnetic sensor arrangement, respectively, and along a third axis parallel to said displacement axis, and compensating said first, second and third magnetic field components for a hardening iron coefficient; - based on the compensated first and second magnetic field components, the value of the current rotation angle (θ) of the shaft (3) in a plane perpendicular to the displacement axis (5) of the shaft (3); ｃ ) is determined, based on the compensated first, second and third magnetic field components, the norm of the magnetic field (N ｃ ) as a squared or non-squared norm, said norm depending on the axial position of the shaft along the displacement axis (5) and on the rotation angle of the shaft, - selecting a compensation function F(θ) that depends on the angle of rotation (θ) of the shaft (3) but that is independent of the axial displacement or axial position (z) of the shaft; - the current rotation angle value (θ ｃ ) to the compensation function to obtain a first value (V ｃ ) is determined, a second value (g ｃ ) and the compensation function is selected such that the second value depends primarily on the axial position of the shaft and less or not on the rotation angle of the shaft; - selecting a relationship between a first set of possible second values and a second set of possible axial displacements or axial positions or / and control values as a function of said possible axial displacements or axial positions, and establishing for each second value of said first set a corresponding axial displacement or axial position of said shaft, or a corresponding range of axial displacements or axial positions of said shaft, or a corresponding control value; an electronic control device (1) comprising means for determining the axial displacement or axial position of the shaft relative to the magnetic sensor arrangement (9), or the control value, by applying the calculated second value to the selected relationship between the first set and the second set.

13. A timepiece comprising an electronic control device according to claim 12.

Images