Rotational position sensing device and method

Abstract

A rotary position sensor is provided. In one example embodiment, the rotary position sensor may include a first component and a second component, one of which has a transmitting antenna and a receiving antenna, while the other of the first and second components has an intermediate coupling element. The receiving antenna has at least one receiving conductive winding arranged to form a first set of current loops and a second set of current loops. The intermediate coupling element comprises a conductive material arranged in a pattern. The pattern of the intermediate coupling element is arranged relative to the layout of the first and second sets of current loops such that any electromotive force induced by the background magnetic field in the first set of current loops is substantially balanced by an electromotive force induced by the background magnetic field in the second set of current loops.

Description

[0001] This application is a divisional application of Chinese Invention Patent Application No. 201880094054.5 (Applicant: AB Electronics Ltd., Invention Title: Rotational Position Sensing Device and Method), which was filed on May 29, 2018, under PCT application PCT / GB 2018 / 051453 and entered the Chinese national phase. Technical Field

[0002] An exemplary aspect of this disclosure relates to the sensing of the relative rotational position between two components. Background Technology

[0003] Various forms of inductive position sensors are known for detecting the position of a first component relative to a second component. In some cases, one component carries both a transmitting and receiving antenna, while the other carries an intermediate coupling element. The transmitting and receiving antennas are arranged such that, in the absence of the intermediate coupling element, the magnetic field generated by the alternating current flowing through the transmitting antenna induces a zero signal in the receiving antenna (the transmitting and receiving antennas are then referred to as balanced). However, in the presence of the intermediate coupling element, the magnetic field generated by the alternating current flowing through the transmitting antenna induces an electromotive force (EMF) in the receiving antenna, and the current generated by this EMF depends on the position of the intermediate coupling element relative to the transmitting and receiving antennas. By analyzing this current, the relative position of the two components can be determined. Summary of the Invention

[0004] According to a first aspect, a rotational position sensor is provided, comprising a first component and a second component, one of which has a transmitting antenna and a receiving antenna, and the other having an intermediate coupling element. The transmitting antenna has at least one conductive winding arranged such that a current flowing through the transmitting conductive winding generates a magnetic field, and the receiving antenna has at least one receiving conductive winding arranged to form a first set of current loops and a second set of current loops, the first and second sets of current loops being arranged such that a current flowing in the receiving conductive winding flows with a first rotational sensibility in the first set of current loops and with a second rotational sensibility opposite to the first rotational sensibility in the second set of current loops. The intermediate coupling element comprises a patterned conductive material such that the net electromotive force induced in the conductive winding of the receiving antenna by the magnetic field generated by the transmitting antenna varies according to the relative rotational positions of the first and second components. The pattern of the intermediate coupling element is arranged to correspond with the arrangement of the first and second sets of current loops, such that any electromotive force induced in the first set of current loops by an alternating background magnetic field is substantially balanced by the electromotive force induced in the second set of current loops by the alternating background magnetic field, regardless of the relative rotational positions of the first and second components.

[0005] Further aspects are set forth in the appended claims.

[0006] Other features and advantages of this disclosure will become apparent from the following description of preferred embodiments, which are given by way of example only and with reference to the accompanying drawings. Attached Figure Description

[0007] Figure 1 The main components of the rotary position sensor are shown.

[0008] Figure 2 A plan view showing the layout of the transmitting and receiving antennas on the first component of the rotary position sensor according to the first example is shown;

[0009] Figure 3 A plan view is shown of a conductive pattern forming an intermediate coupling element on a second component of a rotary position sensor according to a first example;

[0010] Figure 4A The layout of the conductive winding forming the transmitting antenna of the rotary position sensor according to the first example is shown;

[0011] Figure 4B The layout of the conductive winding forming the sinusoidal winding of the receiving antenna of the rotary position sensor according to the first example is shown.

[0012] Figure 4C The layout of the conductive winding forming the cosine winding of the receiving antenna of the rotary position sensor according to the first example is shown.

[0013] Figure 5 It schematically shows that in Figure 3 In the absence of the intermediate coupling element shown, the alternating background magnetic field is used in... Figure 4B The electromotive force generated in the sinusoidal winding shown;

[0014] Figure 6 It schematically shows that in Figure 3 In the presence of the intermediate coupling element shown, the alternating background magnetic field is used to... Figure 4B The electromotive force generated in the sinusoidal winding shown;

[0015] Figure 7 A plan view showing the layout of the transmitting and receiving antennas on the first component of the rotary position sensor according to the second example is shown;

[0016] Figure 8 A plan view is shown of a conductive pattern forming an intermediate coupling element on a second component of a rotary position sensor according to a second example;

[0017] Figure 9A The layout of the conductive winding forming the transmitting antenna of the rotary position sensor according to the second example is shown;

[0018] Figure 9B The layout of the conductive winding that forms the sinusoidal winding of the receiving antenna of the rotary position sensor according to the second example is shown;

[0019] Figure 9C The layout of the conductive winding forming the cosine winding of the receiving antenna of the rotary position sensor according to the second example is shown.

[0020] Figure 10 It schematically shows that in Figure 8 In the absence of the intermediate coupling element shown, the alternating background magnetic field in Figure 9B The electromotive force generated in the sinusoidal winding shown;

[0021] Figure 11 It schematically shows that in Figure 8 In the presence of the intermediate coupling element shown, the alternating background magnetic field in Figure 9B The electromotive force generated in the sinusoidal winding shown;

[0022] Figure 12 A plan view showing the layout of the transmitting and receiving antennas on the first component of the rotary position sensor according to the third example is shown;

[0023] Figure 13A The layout of the conductive winding forming the transmitting antenna of the rotary position sensor according to the third example is shown;

[0024] Figure 13B The layout of the conductive winding that forms the sinusoidal winding of the receiving antenna of the rotary position sensor according to the third example is shown.

[0025] Figure 13C The layout of the conductive winding forming the cosine winding of the receiving antenna of the rotary position sensor according to the third example is shown.

[0026] Figure 14 It schematically shows the situation in relation to Figure 8 In the presence of the matching intermediate coupling element shown, the alternating background magnetic field is used in... Figure 13B The electromotive force generated in the sinusoidal winding shown;

[0027] Figure 15 A plan view showing the layout of the transmitting and receiving antennas on the first component of the rotary position sensor according to the fourth example is shown;

[0028] Figure 16A The layout of the conductive winding forming the transmitting antenna of the rotary position sensor according to the fourth example is shown.

[0029] Figure 16BThe layout of the conductive winding that forms the sinusoidal winding of the receiving antenna of the rotary position sensor according to the fourth example is shown.

[0030] Figure 16C The layout of the conductive winding that forms the cosine winding of the receiving antenna of the rotary position sensor according to the fourth example is shown.

[0031] Figure 17 An intermediate coupling element according to the fourth example is shown;

[0032] Figure 18 An intermediate coupling element according to the fifth example is shown;

[0033] Figure 19 An intermediate coupling element according to the sixth example is shown;

[0034] Figure 20 An intermediate coupling element according to the seventh example is shown;

[0035] Figure 21 An intermediate coupling element according to the eighth example is shown; and

[0036] Figure 22 An intermediate coupling element is shown according to another example. Detailed Implementation

[0037] Now refer to Figures 1 to 6 A rotary position sensor according to an example embodiment of this disclosure is described. For example... Figure 1 As schematically shown in this example, the rotary position sensor has a transmitting antenna 1, a receiving antenna formed by a sine winding 3 and a cosine winding 5, and an intermediate coupling element 7. The transmitting antenna 1 and the receiving antenna are formed on a first member (not shown), and the intermediate coupling element 7 is formed on a second member (also not shown), such that relative rotational movement between the first member and the second member results in a corresponding relative rotational movement, on the one hand, between the transmitting antenna 1 and the receiving antenna, and on the other hand, between the intermediate coupling element.

[0038] The transmitting antenna 1, the sine winding 3, and the cosine winding 5 are each formed by their respective conductive windings, the ends of which are electrically connected to corresponding terminals of the processing circuit 9. In this example, the processing circuit 9 is in the form of a semiconductor integrated circuit device, such as an application-specific integrated circuit (ASIC) or a standard application-specific product (ASSP). In other examples, the processing circuit 9 may alternatively utilize multiple interconnected devices and / or may be implemented using one or more suitable components (e.g., electronic components, such as discrete electronic components).

[0039] like Figure 1As shown, the processing circuit 9 includes a TX driver stage 11, which generates an oscillating electrical signal to be provided to the transmitting antenna 1. In this example, the TX driver stage 11 is a free-running oscillator that generates the oscillating electrical signal at a drive frequency determined by the inductance of the transmitting antenna 1 and the capacitance of the capacitor 13 connected in parallel with the transmitting antenna 1. This drive frequency is typically chosen to be a few MHz, for example, in the range of about 1 MHz to about 6 MHz. As used herein, the term "about" in conjunction with a numerical value is intended to mean within 20% of said value.

[0040] Providing an oscillating current to the transmitting antenna 3 induces an electromotive force in the sinusoidal winding 3 and the cosine winding 5, causing current to flow in both windings. For example... Figure 1 As shown, the sine winding 3 and the cosine winding 5 are separate windings, such that separate currents flow in the sine winding 3 and the cosine winding 5. The sine winding 3 and the cosine winding 5 are electrically connected to separate terminals of the processing circuit 9. The current flowing in the sine winding 3 is processed to provide a sine output signal 23, while the current flowing in the cosine winding 5 is processed to provide a cosine output signal 25. The relative magnitudes of the sine output signal 23 and the cosine output signal 25 indicate the relative rotational positions of the first and second components.

[0041] Upon entering the processing circuit 9, the current flowing in the sinusoidal winding 3 first passes through the EMC filter stage 15 to reduce signal components at frequencies far from the drive frequency. For example, the filtered signal components may be caused by interference from electrical signals generated by other nearby electrical components.

[0042] The filtered electrical signal then passes through a synchronous demodulation stage 17, where it is mixed with the demodulated signal from the TX drive stage 11. The demodulated signal is in phase with the drive signal, and because the intermediate coupling element 7 is formed of a conductive material, the electrical signal from the sinusoidal winding 3 is 180° out of phase with the drive signal. Therefore, the demodulated electrical signal generated by synchronous demodulation has a baseband component, the magnitude of which varies depending on the relative rotational position of the first and second components and the higher frequency components at twice the drive frequency and at higher harmonics of the drive frequency.

[0043] The demodulated electrical signal then passes through a low-pass filter stage 19 to remove high-frequency components corresponding to the harmonics of the drive signal, leaving the baseband components, and then passes through a gain and output buffer stage 21, thereby allowing an adjustable gain to be applied before the processing circuit 9 outputs a sinusoidal output signal 23.

[0044] from Figure 1 It can be clearly seen that the current induced in the cosine winding 5 passes through the EMC filter 15, synchronous demodulation 17, low-pass filter 19, and gain and output buffer 21 in the processing circuit 9 before being output as the cosine output signal 25.

[0045] The transmitting antenna 1, the sine winding 3 and the cosine winding 5 are formed by conductive traces arranged on the first component, while the intermediate coupling element 7 is formed by a pattern 31 of conductive material arranged on the second component.

[0046] In this example, Figure 2 The layout of the conductive traces on the first component is shown. Figure 3 A pattern 31 of the conductive material on the second component is shown. For ease of illustration, Figure 4A , 4B Figures 4C and 4C separately show the conductive traces forming the transmitting antenna 1, the conductive traces forming the sine winding 3, and the conductive traces forming the cosine winding 5. From... Figure 2 It can be seen that the conductive traces form a pattern that is approximately rotationally symmetrical about the rotation axis 29 of the first component.

[0047] like Figure 4A As shown, the conductive traces forming the transmitting antenna 1 have: an inner loop 41 that surrounds the central portion of a first radial range 49a extending from the rotation axis 29; and an outer loop 43 that surrounds the inner loop 41, such that a loop is formed between the inner loop 41 and the outer loop 43 in a second radial range 49b. Figure 4A From the perspective of the angle, the drive current supplied to the conductive trace at terminal 45 flows around the outer group circuit 43 with a rotational feel (e.g., clockwise) and around the inner group circuit 41 with an opposite rotational feel (e.g., counterclockwise). The drive current then flows to terminal 47 (it should be understood that the radial portions of the conductive traces passing through the inner group circuit 41 and the radial portions of the conductive traces passing through the outer group circuit are electrically insulated from the inner group circuit 41 and the outer group circuit 43, respectively). By providing an oscillating electrical signal to the transmitting antenna 1, a magnetic field is generated having a field component of one polarity passing through the loop between the inner group circuit 41 and the outer group circuit 43 and a field component of opposite polarity passing through the central portion surrounded by the inner group circuit 41.

[0048] like Figure 4B As shown, the sinusoidal winding 3 forms two sets of current loops. The current flowing in one set of current loops 51a-51d with a rotational inclination (e.g., clockwise) flows in the second set of current loops with a different rotational inclination (e.g., counterclockwise). The first set of current loops 51 intersects the second set of current loops 53 symmetrically at an angle. Therefore, advancing along the direction of rotation, the layout of the conductive windings forming the sinusoidal winding 3 repeats periodically, each cycle including the first set of loops 51 and the second set of loops 53. In this example, there are four cycles, but other numbers of cycles can also be used.

[0049] In a similar way, such as Figure 4CAs shown, the cosine winding forms two sets of current loops. Current flows in a rotational inclination (e.g., clockwise) in the first set of current loops 61a-61d, and in the opposite rotational inclination (e.g., counterclockwise) in the second set of current loops 63a-63d. The first set of current loops 61 intersects the second set of current loops 63 symmetrically at an angle. Therefore, advancing along the direction of rotation, the layout of the conductive windings forming the cosine winding 5 repeats periodically, each cycle including the first set of loops 61 and the second set of loops 63. The cosine winding 5 has the same number of windings as the sine winding 3, but is angularly offset by a quarter cycle relative to the sine winding 3.

[0050] In the absence of the intermediate coupling element 7, the electromotive force directly induced in the sinusoidal winding 3 by the magnetic field generated by the transmitting antenna 1 is balanced, resulting in no current flowing directly in the sinusoidal winding 3 due to the magnetic field generated by the transmitting antenna 1. Furthermore, as... Figure 5 As illustrated, in the absence of the intermediate coupling element 7, the electromotive forces induced in the sinusoidal winding 3 by any alternating background magnetic field that is substantially uniform within the range of the sinusoidal winding 3 are substantially balanced, resulting in substantially no associated current flow. Similarly, in the absence of the intermediate coupling element 7, the electromotive forces directly induced in the cosine winding 5 by the magnetic field generated by the transmitting antenna 1 are balanced, such that no current flows directly in the cosine winding 5 due to the magnetic field generated by the transmitting antenna 1. Likewise, the electromotive forces induced in the cosine winding 5 by any alternating background magnetic field that is substantially uniform within the range of the cosine winding 5 are substantially balanced, resulting in substantially no associated current flow.

[0051] like Figure 3 As shown, the pattern 31 of the conductive material forming the intermediate coupling element is also periodically repeated along the rotation direction, having the same number of cycles as the sine winding 3 and the cosine winding 5 (four in this example). Each cycle corresponds to a circular sector 33 and is formed by two adjacent, non-overlapping sub-sectors 35a, 35b. In the first sub-sector 35a, there is no conductive material in the first radial range 37a extending from the center of the pattern to the first radial position, but there is conductive material in the second radial range 37b extending from the first radial position to the second radial position. In the second sub-sector 35b, there is conductive material in the first radial range 37a, but no conductive material in the second radial range 37b, so that the sub-patterns in the first and second sub-sectors 35a, 35b are complementary. At the boundary between the first radial range 37a and the second radial range 37b, a gap is provided between the conductive materials in the first sub-sector 37a and the second sub-sector 37b to avoid the formation of undesirable current loops.

[0052] Figure 6The conductive pattern 31 of the intermediate coupling element 7 superimposed on the sinusoidal winding 3 in a relative rotational position of the first and second components is shown. Regarding the magnetic field generated by the transmitting antenna 1, coupling occurs in the current loop 51 of the first set of current loops in the first radial range 37a of the conductive pattern 31, and coupling occurs in the second set of current loops in the second radial range 37b of the conductive pattern 31. However, assuming that the polarity of the magnetic field generated by the transmitting antenna 1 in the first radial range 37a is opposite to the polarity of the magnetic field generated by the transmitting antenna 1 in the second radial range 37b, the induced electromotive forces act together to generate a current in the sinusoidal winding 3. The magnitude of the current induced in the sinusoidal winding 3 due to the magnetic field generated by the transmitting antenna 1 will vary depending on the relative rotational position of the first and second components according to the first and second sine functions. Similarly, the magnitude of the current induced in the cosine winding 5 due to the magnetic field generated by the transmitting antenna 1 will vary depending on the relative rotational position of the first and second components according to the second sine function which is 90° out of phase with the first sine function.

[0053] Regarding any alternating background magnetic field, the conductive material of the intermediate coupling element 7 shields adjacent portions of the receiving antenna. However, the pattern 31 of the intermediate coupling element 7 is arranged in relation to the layout of the first set of current loops 51 and the second set of current loops 53 of the sinusoidal winding 3, such that any electromotive force induced in the first set of current loops 51 by the remaining background alternating magnetic field is substantially balanced by the electromotive force induced in the second set of current loops 53 by the background alternating magnetic field. This is independent of the relative rotational positions of the first and second elements. For any component of the background magnetic field at frequencies close to the driving frequency, it is not filtered out by EMC filtering and synchronous demodulation, which removes possible noise components from the signal corresponding to the field-induced current generated by the transmitting antenna 1, thereby improving the signal-to-noise ratio.

[0054] Reference Figures 1 to 6 The described example differs from conventional designs in the patterning of the conductive material 31 forming the intermediate coupling element 7 and the layout of the conductive traces of the transmitting antenna 1. As mentioned above, this difference can achieve many technical effects and benefits. For example, the difference can achieve a balance of electromagnetic forces induced in the sinusoidal winding 3 and the cosine winding 5 through a uniform alternating background magnetic field, independent of the relative rotational positions between the first and second components. Reference will now be made to... Figure 7 Sections 9 to 9 describe another rotary position sensor according to exemplary embodiments of the present disclosure, wherein the rotary sensor differs from conventional designs in the arrangement of the transmitting and receiving antennas to achieve the same effect.

[0055] In this example, Figure 7 The layout of conductive traces forming the transmitting antenna 1 and the receiving antenna 71 on the first component is shown, while Figure 8A pattern 81 of conductive material on the second component is shown. For ease of illustration, Figure 9A , 9B Figures 9C and 9C separately show the conductive traces forming the transmitting antenna 1, the conductive traces forming the sine winding 3, and the conductive traces forming the cosine winding 5. For example... Figure 7 As shown, the conductive traces of the transmitting antenna 1 and the receiving antenna 1 are approximately rotationally symmetrical about the rotation axis 29 of the first component.

[0056] from Figure 9A As can be seen from this, the conductive traces forming the transmitting antenna 1 are similar to those forming... Figure 4A The conductive traces of the transmitting antennas in the previous examples shown have substantially the same layout; therefore, the same reference numerals are used to refer to the same features. Specifically, the conductive traces have: an inner group loop 41 that surrounds the central portion of a first radial range 49a extending from the rotation axis 29; and an outer group loop 43 that surrounds the inner group loop 41, such that a loop is formed between the inner group loop 41 and the outer group loop 43 on a second radial range 49b. Figure 9A From the perspective of the angle, the drive current supplied to the conductive trace at terminal 45 flows around the outer group circuit 43 with a rotational feel (e.g., clockwise) and around the inner group circuit 41 with an opposite rotational feel (e.g., counterclockwise). The drive current then flows to terminal 47 (it should be understood that the radial portions of the conductive traces passing through the inner group circuit 41 and the radial portions of the conductive traces passing through the outer group circuit are electrically insulated from the inner group circuit 41 and the outer group circuit 43, respectively). By providing an oscillating electrical signal to the transmitting antenna 1, a magnetic field is generated having a field component of one polarity passing through the loop between the inner group circuit 41 and the outer group circuit 43 and a field component of opposite polarity passing through the central portion surrounded by the inner group circuit 41.

[0057] like Figure 9BAs shown, the sinusoidal winding of the receiving antenna 71 forms two sets of current loops. In the first set of current loops 91a-91d, the current flows along a rotational direction (e.g., clockwise), while in the second set of current loops 53a-53d, the current flows along another rotational direction (e.g., counterclockwise). Current loops 91 and 93 are formed by a first sub-loop within a first radial range 95a and a second sub-loop within a second radial range, respectively. The second radial range extends beyond the first radial range without overlapping, and the first and second sub-loops are angularly offset. The first set of current loops 91 and the second set of current loops 93 intersect each other angularly in a symmetrical manner. Therefore, advancing along the direction of rotation, the layout of the conductive winding forming the sinusoidal winding 3 is periodically repeated on circular sectors. Sector 97 includes a first sub-sector angularly adjacent to the second sub-sector, wherein the first sub-sector includes a sub-loop of one of the first set of current loops 91 within a first radial range 95a, and a sub-loop of one of the second set of current loops 93 within a second radial range 95b, and wherein the second sub-sector includes a sub-loop of one of the second set of current loops 93 within the first radial range 95a, and a sub-loop of one of the first set of current loops 91 within the second radial range 95b. In this example, there are four cycles, but other numbers of cycles may also be used.

[0058] In a similar way, such as Figure 9C As shown, the cosine winding forms two sets of current loops. Current flows in a rotational inclination (e.g., clockwise) in the first set of current loops 101a-101d, while it flows in the opposite rotational inclination (e.g., counterclockwise) in the second set of current loops 103a-103d. The current in the first set 101a flows in a rotational inclination (e.g., counterclockwise) with... Figure 9B The sinusoidal winding shown is symmetrically intersected angularly with the second group of current loops 103 in the same manner, but is offset angularly by a quarter cycle relative to the sinusoidal winding.

[0059] In the absence of an intermediate coupling element, the electromotive force directly induced in the sinusoidal winding by the magnetic field generated by the transmitting antenna 1 is balanced, resulting in no current flowing directly in the sinusoidal winding 3 due to the magnetic field generated by the transmitting antenna 1. Furthermore, as... Figure 10As illustrated schematically, in the absence of an intermediate coupling element, the electromotive forces induced in the sinusoidal winding by any background magnetic field that is substantially uniform within the range of the sinusoidal winding are substantially balanced, resulting in substantially no associated current flow. Similarly, in the absence of an intermediate coupling element, the electromotive forces directly induced in the cosine winding by the magnetic field generated by transmitting antenna 1 are balanced, such that no current flows directly in the cosine winding due to the magnetic field generated by transmitting antenna 1. Likewise, the electromotive forces induced in the cosine winding by any background magnetic field that is substantially uniform within the range of the cosine winding are substantially balanced, resulting in substantially no associated current flow.

[0060] like Figure 8 As shown, the pattern 81 of the conductive material forming the intermediate coupling element also repeats periodically in the rotational direction, with the same number of cycles as the sine and cosine windings (four in this example). Each cycle corresponds to a circular sector and is formed by two adjacent, non-overlapping sub-sectors. There is no conductive material in the first sub-sector 35a, but there is conductive material in the second sub-sector 35b. This corresponds to the conventional design of the intermediate coupling element.

[0061] For any alternating background magnetic field, the pattern 81 of the intermediate coupling element and the layout of the first set of current loops 91 and the second set of current loops 93 of the sinusoidal winding are arranged in relation to each other, such that... Figure 11 As shown, any electromotive force induced by the background alternating magnetic field in the first current loop 91 is substantially balanced by the electromotive force induced by the background alternating magnetic field in the second current loop 93. This is independent of the relative rotational positions of the first and second components. Any component of the background magnetic field at frequencies close to the driving frequency is not filtered out by EMC filtering and synchronous demodulation, which removes possible noise components from the signal corresponding to the field-induced current generated by the transmitting antenna 1, thereby improving the signal-to-noise ratio.

[0062] In reference Figures 1 to 6 and Figures 7 to 11 In the described example, the transmitting and receiving antennas extend 360°, thus providing data indicating the relative positions of the first and second components throughout the entire range of rotational motion (it will be appreciated that the provided data may not indicate a unique position, but rather one of a finite number of possible positions). In other rotational sensors, the relative motion of the first and second components can be limited to an angular range. For such an arrangement, it is known that the transmitting and receiving antennas are positioned only on a sector of the first component, depending on the range of angular motion. However, conventional arrangements suffer from noise problems caused by the background alternating magnetic field. Figures 12 to 14 Rotational positions according to exemplary embodiments of the present disclosure are depicted, in which the embodiments employ a layout of transmitting and receiving antennas to reduce such noise in rotational position sensors with a limited range of motion angles.

[0063] Figure 12 The layout of the conductive windings forming the transmitting and receiving antennas on the first component is shown. For ease of illustration, Figures 13A to 13C Conductive trace 131 forming a transmitting antenna, conductive trace 141 forming a sinusoidal winding forming a receiving antenna, and conductive trace 151 forming a cosine winding forming a receiving antenna are shown respectively.

[0064] like Figure 13A As shown, the conductive trace 131 forming the transmitting antenna has a first loop 133a that is approximately aligned with a first small arc of a circle centered on the axis of rotation, and a second loop 133b that is diametrically opposite to the first loop and approximately aligned with a second small arc of a circle centered on the axis of rotation. At any given time, current flows through the first loop 133a and the second loop 133b with opposite rotational intuition (i.e., from...). Figure 13A From the perspective of the current flowing clockwise through the first circuit 133a and counterclockwise through the second circuit 133b (and vice versa), the alternating current flowing through the conductive trace 131 generates a magnetic field due to the current flowing through the first circuit 133a. The polarity of this magnetic field is opposite to that generated by the current flowing through the second circuit 133b. It should be understood that the first circuit 133a and the second circuit 133b are connected by two separate conductive traces that are insulated from each other but follow substantially the same path.

[0065] like Figure 13B As shown, the conductive trace 141 forming the sinusoidal winding of the receiving antenna has a first set of current loops including two current loops 143a and 143b, and a second set of current loops including two current loops 145a and 145b. The conductive trace 141 is wound such that current flowing in the conductive trace 141 will flow through the first set of current loops 143 with a rotational feel, and through the second set of current loops 145 with an opposite rotational feel. One current loop 143a in the first set of current loops and one current loop 145a in the second set of current loops are generally aligned with the first loop 133a of the conductive trace 131 of the transmitting antenna, but are angularly spaced from each other. Similarly, the other current loop 143b in the first set of current loops and the other current loop 145b in the second set of current loops are generally aligned with the second loop 133b of the conductive trace 131 of the transmitting antenna, but are angularly spaced from each other. Each current loop 143 in the first set of current loops is diametrically opposed to the current loop 145 in the second set of current loops. It should be understood that the first loop 143a and the second loop 143b of the first set of current loops are connected by two separate conductive traces that are insulated from each other but follow substantially the same path.

[0066] like Figure 13CAs shown, the layout of the cosine winding of the receiving antenna, the conductive trace 151, basically corresponds to the layout of the conductive trace of the sine winding rotating a quarter cycle.

[0067] In this example, the pattern of the conductive material forming the intermediate coupling element is consistent with... Figure 8 The patterns shown are identical and will be referenced using the same reference numeral 81.

[0068] For any alternating background magnetic field, the pattern 81 of the intermediate coupling element and the layout of the first set of current loops 143 and the second set of current loops 145 of the sinusoidal winding are arranged in relation to each other, such that... Figure 14 As shown, any electromotive force induced by the background alternating magnetic field in the current loop of the first set of current loops 143 is substantially balanced by the electromotive force induced by the background alternating magnetic field in the current loop of the second set of current loops 145. This is independent of the relative rotational positions of the first and second components. Any component of the background magnetic field at frequencies close to the driving frequency is not filtered out by EMC filtering and synchronous demodulation, which removes possible noise components from the signal corresponding to the field-induced current generated by the transmitting antenna 1, thereby improving the signal-to-noise ratio.

[0069] The previously described embodiments all relate to the use of novel transmit antenna layouts and novel receive antenna layouts, or combinations of novel conductive patterns formed on intermediate coupling elements. Reference will now be made to... Figures 15 to 17 Describe an example that uses a novel conductive pattern on an intermediate coupling element.

[0070] Figure 15 Conductive traces formed on the first component to form the transmitting and receiving antennas are shown. For ease of illustration, each is shown separately. Figures 16A to 16B The diagram shows conductive trace 171 forming a transmitting antenna, conductive trace 181 forming a sinusoidal winding, and conductive trace 191 forming a cosine winding. (See diagram for reference.) Figure 16A As shown, the conductive traces forming the transmitting antenna are formed by a set of loops with similar radii centered on the axis of rotation. Figure 16B and 16C As shown, the conductive traces 181 forming the sinusoidal winding for the receiving antenna and the conductive traces forming the cosine winding for the receiving antenna are respectively located in... Figure 4B and 4C The basic structure shown is the same.

[0071] In this example, such as Figure 17 As shown, the conductive material 201 on the intermediate coupling element is in the form of a continuous pattern with varying thickness. Specifically, in this example, the conductive material 201 extends over the entire range of the receiving antenna and has a region with a first thickness d1 and a second thickness d2. By comparison... Figure 17 and Figure 8 It can be seen that, Figure 17 The region with a first thickness d1 in the intermediate coupling element basically corresponds to the region in the middle coupling element. Figure 8 There are regions in which there is no conductive material, while Figure 17 The region with a second thickness d2 in the intermediate coupling element basically corresponds to the region in the middle coupling element. Figure 8 There is a region containing conductive material. Those skilled in the art will understand that, regarding the magnetic field generated by the alternating current flowing through the conductive trace 171 of the conductive material, depending on the relative rotational positions of the first and second components, by means of... Figure 8 The pattern of the conductive material 201 in the intermediate coupling element will induce electromagnetic forces in the conductive traces 181 and 191 of the receiving antenna. Furthermore, Figure 17 The conductive material 201 of the intermediate coupling element, extending continuously above the receiving antenna, shields the receiving antenna from the alternating background magnetic field, thereby reducing noise. In this example, the difference between the first thickness d1 and the second thickness d2 is approximately on the same order of magnitude as the loop widths of the sine and cosine windings, resulting in good signal strength.

[0072] In some embodiments, Figure 17 The intermediate coupling element can be made of Figure 18 An intermediate coupling element is used instead to increase signal strength. In this example, a thin layer of ferromagnetic material 211 is formed on a non-conductive substrate 213 (e.g., a printed circuit board), and its pattern is consistent with... Figure 8 Pattern matching of the conductive material of the intermediate coupling element. Given the thinness of the ferromagnetic material, the alternating background magnetic field will pass through essentially unimpeded. Figure 18 The intermediate coupling element. Therefore, any electromotive force induced by the background alternating magnetic field in the current loop of the first set of current loops 141 is substantially balanced by the electromotive force induced by the background alternating magnetic field in the current loop of the second set of current loops 143.

[0073] Figure 17 and 18 An intermediate coupling element is illustrated, wherein the conductive material of the intermediate coupling element overlaps with the entire receiving antenna, thereby protecting the receiving antenna from any background alternating magnetic field. In some embodiments, the intermediate coupling element consists of alternating sectors of conductive and ferromagnetic materials to interact with... Figure 17 and 18 The same pattern is formed as shown. In this arrangement, noise components will be present in the current flowing in the sine and cosine windings because the ferromagnetic material cannot shield the receiving antenna from the background alternating magnetic field. However, since both the conductive and ferromagnetic materials contribute to the signal components of the current flowing in the sine and cosine windings in a cooperative manner, given the difference in phase shift imparted by the conductive and ferromagnetic materials, the signal-to-noise ratio is still improved as the signal increases.

[0074] although Figure 3 and 8 The intermediate coupling element has a pattern formed by a uniform range of conductive material, but this is not necessary. For example... Figure 19 As shown, Figure 3 The pattern can be replaced by pattern 221, in which each area of ​​the conductive material is replaced by a conductive loop corresponding to the periphery of that area. For Figure 19 The intermediate coupling element, the alternating background magnetic field will induce an electromotive force, which causes currents with the same direction of motion to flow in each loop, thereby generating a magnetic field opposite to the background magnetic field. Thus, Figure 19 intermediate coupling element to with Figure 3 The intermediate coupling element provides shielding against the background alternating magnetic field in a similar manner. Therefore, for utilizing... Figure 3 The embodiment of the intermediate coupling element can be alternatively used. Figure 19 The intermediate coupling element.

[0075] In a similar way, Figure 20 The pattern 231 of conductive traces is shown, which can replace Figure 8 The intermediate coupling element is used.

[0076] Can be used as an alternative Figure 19 The conductive traces forming a loop in the intermediate coupling element are connected to form a closed conductive winding 241 (i.e., a conductive winding with interconnected ends), such as... Figure 21 As shown, or multiple closed conductive windings, such as Figure 22 As shown, the conductive traces form four conductive windings 25la-25ld, where each conductive winding forms a balanced set of clockwise and counterclockwise loops relative to the uniform background magnetic field. For Figure 21 and 22 The intermediate coupling element does not shield the receiving antenna from the background magnetic field. The balance of the conductive winding relative to the background magnetic field results in no net current flowing through the intermediate coupling element due to the alternating background magnetic field. Therefore, there is no shielding effect of the intermediate coupling element relative to the conductive winding of the receiving antenna. Figure 21 and 22 The intermediate coupling element effectively and completely eliminates the shielding effect of the intermediate coupling element on the alternating background magnetic field. Assuming the receiving antenna itself is balanced relative to the background magnetic field, noise in the receiving antenna caused by the alternating background magnetic field is essentially avoided. Therefore, for utilizing... Figure 3 The embodiment of the intermediate coupling element can be alternatively used. Figure 21 Or 22 intermediate coupling elements.

[0077] exist Figures 12 to 14In the example, each loop in the first set of loops is diametrically opposite a loop in the second set of current loops. In some embodiments, the different segments may be rotated relative to each other by any multiple of half the periodicity of the conductive pattern of the intermediate coupling element.

[0078] Although the receiving antenna has both sine and cosine windings in all the examples given above, this is not necessary, and only one type of sine or cosine winding can be used. In such an arrangement, the magnitude of the oscillating drive current applied to the transmitting antenna can be varied using a feedback signal, thereby allowing position information to be derived solely from the current flowing in a single sine / cosine winding. The above embodiments should be understood as illustrative examples of this disclosure.

[0079] Other embodiments of this disclosure are contemplated. It should be understood that any feature described with respect to any embodiment may be used alone or in combination with other described features, and may also be used in combination with one or more features of any other embodiment or in any combination of any other embodiment. Furthermore, equivalents and modifications not described above may be employed without departing from the scope of the invention as defined by the appended claims.

Claims

1. A rotational position sensor, comprising a first component and a second component, one of the first and second components having a transmitting antenna and a receiving antenna, while the other of the first and second components has an intermediate coupling element. The transmitting antenna includes at least one conductive winding arranged such that an alternating current flowing in the at least one conductive winding generates an alternating magnetic field for transmission. The receiving antenna includes a conductive winding arranged in a layout having a first set of current loops and a second set of current loops, such that current flowing in the conductive winding flows along a first rotational inclination in the first set of current loops and along a second rotational inclination opposite to the first rotational inclination in the second set of current loops. The intermediate coupling element comprises a conductive material arranged in a pattern such that the electromotive force induced in the conductive winding of the receiving antenna by the transmitting alternating magnetic field varies according to the relative rotational positions of the first and second components. wherein The pattern of the intermediate coupling element is arranged in relation to the layout of the first set of current loops and the second set of current loops, such that any electromotive force induced by the background alternating magnetic field in the first set of current loops is basically balanced with the electromotive force induced by the background alternating magnetic field in the second set of current loops, regardless of the relative rotational position of the first and second components. The transmitting antenna includes a first current loop in a first section of the first component and a second current loop in a second section of the first component, wherein the first current loop and the second current loop of the transmitting antenna are arranged to generate magnetic fields of opposite polarities. The receiving antenna includes at least one first set of current loops and at least one second set of current loops in the first segment, and at least one second set of current loops in the second segment. The intermediate coupling element is arranged such that when the conductive material is present near the current loop of the first set of current loops in the first section, the conductive material is present near the current loop of the second set of current loops in the second section. The first and second sections are radially opposite each other.

2. A rotational position sensor, comprising a first component and a second component, one of the first and second components having a transmitting antenna and a receiving antenna, while the other of the first and second components has an intermediate coupling element. The transmitting antenna includes at least one conductive winding arranged to form a first loop and a second loop. The first loop is aligned with a first minor arc of a circle centered on the axis of rotation, and the second loop is diametrically opposite to the first loop and aligned with a second minor arc of a circle centered on the axis of rotation. Current flows through the first and second loops with opposite rotational inertia, such that alternating current flowing in the at least one conductive winding generates an alternating magnetic field for transmission. The receiving antenna includes a conductive winding arranged in a layout having a first set of current loops and a second set of current loops, such that current flowing in the conductive winding flows along a first rotational inclination in the first set of current loops and along a second rotational inclination opposite to the first rotational inclination in the second set of current loops. The intermediate coupling element comprises a conductive material arranged in a pattern such that the electromotive force induced in the conductive winding of the receiving antenna by the transmitting alternating magnetic field varies according to the relative rotational positions of the first and second components. The conductive material repeats periodically in the rotational direction, with the same number of cycles as the sine and cosine windings. Each cycle corresponds to a circular sector and is formed by two adjacent, non-overlapping sub-sectors. In the first sub-sector, there is no conductive material, while in the second sub-sector, conductive material is present. wherein The pattern of the intermediate coupling element is arranged in relation to the layout of the first set of current loops and the second set of current loops, such that any electromotive force induced by the background alternating magnetic field in the first set of current loops is substantially balanced with the electromotive force induced by the background alternating magnetic field in the second set of current loops, regardless of the relative rotational position of the first and second components.

3. The rotary position sensor of claim 2, wherein, Compared to the second region of the conductive material, the first region of the conductive material is arranged closer to the receiving antenna, such that the current induced in the conductive winding of the receiving antenna by the magnetic field generated by the transmitting antenna varies according to the relative rotational positions of the first and second components.

4. The rotary position sensor of claim 2, wherein, A ferromagnetic material pattern is formed on the conductive material, the ferromagnetic material pattern being arranged such that the current induced in the conductive winding of the receiving antenna by the magnetic field generated by the transmitting antenna varies according to the relative rotational positions of the first and second components.

5. The rotary position sensor of claim 2, wherein, The conductive material of the intermediate coupling element includes one or more closed conductive windings, each closed conductive winding including a balanced set of clockwise and counterclockwise loops relative to a uniform background magnetic field.

6. The rotary position sensor of claim 2, wherein, The first and second sets of current loops of the receiving antenna have corresponding widths, and wherein a first region of the conductive material of the intermediate coupling element is closer to the receiving antenna by an order of magnitude of the width of the first and second sets of current loops than a second region of the conductive material of the intermediate coupling element.

7. The rotary position sensor according to any one of the preceding claims, further comprising: An excitation circuit is arranged to provide an oscillating electrical signal to the transmitting antenna; as well as A processing circuit is arranged to process the current flowing in the receiving antenna to generate an output signal indicating the relative rotational position of the first and second components.

8. The rotary position sensor of claim 7, wherein, The excitation circuit and the processing circuit are integrated in a semiconductor integrated circuit device.

9. A method for sensing the relative rotational position of a first component and a second component, the method comprising: An oscillating excitation signal is provided to a transmitting antenna formed on the first member. The transmitting antenna includes at least one conductive winding arranged such that an alternating current flowing in the at least one conductive winding generates a transmitting alternating magnetic field. The transmitting antenna includes a first current loop in a first section of the first member and a second current loop in a second section of the first member, wherein the first and second current loops of the transmitting antenna are arranged to generate magnetic fields of opposite polarities. The system processes at least one signal from a receiving antenna formed on the first component, the at least one signal being a result of a current induced in an intermediate coupling element formed on the second component by the transmitting alternating magnetic field. The receiving antenna includes a conductive winding arranged in a layout having a first set of current loops and a second set of current loops. The first and second sets of current loops are arranged such that current flowing in the conductive windings flows with a first rotational inclination in the first set of current loops and with a second rotational inclination opposite to the first rotational inclination in the second set of current loops. The receiving antenna includes at least one first set of current loops and at least one second set of current loops within a first section, and at least one second set of current loops within a second section. The intermediate coupling element comprises a conductive material arranged in a pattern such that the electromotive force induced in the conductive windings of the receiving antenna by the transmitting alternating magnetic field varies according to the relative rotational positions of the first and second elements. The pattern of the intermediate coupling element is arranged in relation to the layout of the first set of current loops and the second set of current loops, such that any electromotive force induced by the background alternating magnetic field in the first set of current loops is substantially balanced with the electromotive force induced by the background alternating magnetic field in the second set of current loops, and is independent of the relative rotational position of the first and second components. The intermediate coupling element is patterned such that when the conductive material is present near the current loop of the first set of current loops in the first segment, the conductive material is also present near the current loop of the second set of current loops in the second segment; and The first and second sections are radially opposite each other.

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