High resolution non-contacting multi-turn position sensor

THE REPUBLIC OF POLAND (12) TRANSLATION OF THE EUROPEAN PATENT (19) pl (ii) PL / EP 2 365 290

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Patent Office of the Republic of Poland (96) Date and number of the European patent application: 17.01.2011 11250047.5 (97) The granting of the European patent was announced: 06.09.2017 European Patent Bulletin 2017/36 EP 2365290 B1 (13) T3 (51) Int.CI.

G01D 5/14 (2006.01) (54) Title of the invention:

HIGH RESOLUTION MULTI-TURN NON-CONTACT POSITION SENSOR (30),

Priority:

01/18/2010 US 689047 (43) Application announced:

2011/37 (45) in the European Patent Bulletin No. 2011/37 (45) The following was announced about the submission of the translation of the patent:

31.01.2018 Patent Office News 2018/01 (73) Patent holder:

Bourns, Inc., Riverside, US (72) Inventor (s):

CO σ&gt; CM IO CD every CM (74)

EUGEN BOGOS, Lakę Elsinore, US PERRY WEHLMAN, Corona, US

Proxy:

thing, pat. Piotr Kamiński KAMIŃSKI AND PARTNERS

KANCELARIA PATENTOWA SP. P. ul. Gerbera 14/13 05-500 Piaseczno

Attention:

Within nine months from the publication of the information on the grant of a European patent, any person may file an objection to the European Patent Office against the granted European patent. The opposition is filed in the form of a written statement of reasons.It is considered to have been brought only upon payment of the opposition fee (Art 99 ( 1) European Patent Convention)

HIGH RESOLUTION MULTI-TURN NON-CONTACT POSITION SENSOR

The present disclosure generally relates to the field of sensors, and more particularly to systems and methods for detecting the angular position of objects such as rotating shafts.

With many mechanical and / or electromechanical devices, it is desirable to accurately determine the state of the rotating object. For example, a rotating object such as a screw jack transfers the mechanical energy associated with linear motion to another object as a result of its rotation. In many cases, it is desirable to precisely identify the position of a linearly moving object. The determination of such a position may be based on the knowledge of the angular position of the rotating object.

In some devices, the angular position may be measured with an angle sensor. Such angle sensors, however, are limited to detecting an angle within only one rotation (360 degrees) or produce ambiguous results when the rotating device performs more than one rotation. An angle sensor using a magnet connected to a rotating shaft is disclosed in US 2008/0079423.

The present invention is defined in the claims. In some embodiments, the present disclosure relates to a device that includes a rotary shaft with a longitudinal axis. The apparatus also comprises a movable carrier connected to the shaft such that rotation of the shaft results in linear movement of the carrier along the longitudinal axis. The device also includes a magnet that has an axis of magnetization and is positioned on the carrier such that it moves with the carrier such that the range of rotation of the shaft translates to the linear range of motion of the magnet along the longitudinal axis. The magnet may be arranged such that the axis of magnetization of the magnet is substantially perpendicular to the longitudinal axis. The apparatus further comprises a magnetic sensor circuit for measuring the magnet, the circuit configured to measure the first flux density along the magnetization axis and the second flux density in a direction perpendicular to the magnetization axis and generate an output signal corresponding to the position of the magnet within the linear range of magnetization, thereby enabling the determination of the rotational position of the shaft in terms of rotation.

In some embodiments, the range of rotation of the shaft is greater than 360 degrees. In some embodiments, the carrier is connected to the shaft by mating threads formed on the carrier and the shaft. In some embodiments, mating threads are selected to generate a range of linear motion based on the range of rotational motion.

In some embodiments, the magnetic sensor circuit consists of a Hall sensor assembly and the second flux corresponds to the longitudinal axis. In some embodiments, the range of linear motion of the magnet is selected such that the measured flux density along the magnetization axis is at its maximum when the position of the magnet is about the center of the linear motion range. In some embodiments, ambiguity in the longitudinal position of the magnet resulting from the measured flux density along the magnetization axis is eliminated by the directivity of the measured flux density along the longitudinal axis.

In these embodiments, the magnetic pickup circuit is programmable to allow an output range to be defined that corresponds to a subset of the shaft rotation range. In some embodiments, a subset of the range of rotation includes M degrees of a shaft rotation. The value of M may be less than, equal to, or greater than 360 degrees. In some embodiments, the value of M is approximately equal to N times 360 degrees, where N is a positive integer greater than 1.

In some embodiments, the output within the output range has an approximately linear relationship to a shaft rotational position within a subset of the shaft rotation range. In some embodiments, the linear relationship has been derived from a number of known responses at shaft rotational positions within a subset of the shaft rotation range.

In some embodiments, the magnetic sensor circuit is configured to generate a signal representative of the rotational position of the shaft. In some embodiments, the magnetic sensor circuit includes an analog-to-digital converter (ADC) whose output includes a digital signal. In some embodiments, the resolution of the digital signal is selected based on a subset of the range of rotation of the shaft.

In some embodiments, the device also includes a sleeve dimensioned sufficient for the sleeve to provide a shaft support structure to facilitate rotation of the shaft relative to the housing. In some embodiments, the device also includes an enclosure to protect the magnetic sensor circuit from external electromagnetic fields. In some embodiments, the sheath is made of a high magnetic permeability material.

In some embodiments, the present disclosure relates to a sensor for determining the rotational position of an object. The sensor comprises a device as described above configured to pivot with the object. The sensor also includes a housing for mounting on a mounting structure, the housing having a curved wall, the first and second walls of which are substantially straight and extend from the ends of the curved wall to form a U-shape when viewed along the longitudinal axis.

In some embodiments, the curved wall is a substantially semi-cylindrical wall curved about an axis that substantially coincides with the longitudinal axis of the shaft. In some embodiments, the carrier has a U-profile sized to slide through the U-shaped wall of the housing.

In some embodiments, the housing is sized to be mounted on a mounting structure so as to be mountable about the axis of the semi-cylindrical wall. In some embodiments, the rotating shaft is connected to the housing in a manner that allows a range of rotation greater than one revolution.

In some embodiments, the housing also includes an enclosure wall opposed to the curved wall. In some embodiments, the closure wall may engage the substantially straight first and second walls such that the closure wall is approximately perpendicular to the substantially straight first and second walls. In some embodiments, the closure wall and the substantially straight first and second walls may define rounded corners. In some embodiments, the closure wall and the substantially straight first and second walls may define substantially square corners.

In some embodiments, the sensor also includes a shield to protect at least the sensor assembly from external fields or radiation. In some embodiments, the shield is configured to suppress X-rays, gamma rays, streams of charged particles, or neutron radiation. In some embodiments, the sensor assembly is disposed on the top of the U-shaped housing. In some embodiments, the shield fits substantially over the top of the U-shaped housing to provide protection against external fields or radiation that are substantially directional. In some embodiments, the housing and the shield are configured to remove the shield.

In some embodiments, the present disclosure is directed to a rotational position sensor comprising the device described above, wherein the rotational range is greater than zero degrees.

In some embodiments, the magnet consists of at least one dipole magnet. In some embodiments, the magnet consists of a dipole magnet having north and south poles along an axis that is substantially perpendicular to the longitudinal axis.

In some embodiments, the present disclosure relates to a rotary position sensor as described above, wherein the range of rotation is greater than 360 degrees, and the magnetic sensor circuit is further configured as a programmable IC having a function to define the range of rotation of the shaft as the operating range of the rotary position sensor.

The following are preferred embodiments of the present invention, illustrated by reference to corresponding examples, with reference to the accompanying figures, of which:

Figure 1 schematically describes an embodiment of a rotation position sensor;

Figures 2A and 2B show that the rotational position sensor of Figure 1 can be configured to mechanically convert input rotation motion into a translational movement range of a sensed element, e.g. a magnet, the translational position of which can be detected by a detection element, e.g. a magnetic field detector;

Figure 3 schematically illustrates that, in some embodiments, the pivot sensor may include a processor and memory to enhance programming capabilities;

Figure 4A shows non-limiting examples of magnet configurations that may be used with the magnet shown in Figure 1;

Figure 4B shows that, in some embodiments, the magnet may be a permanent dipole magnet arranged such that its axis of magnetization is substantially perpendicular to the direction of longitudinal movement of the magnet;

Figure 4C illustrates that, in some embodiments, a magnet may be oriented with respect to its translational movement and the magnetic field detector such that its magnetic axis corresponding to the field distribution at or around the detector is substantially perpendicular to the direction of the translational movement and substantially normal to the plane defined by magnetic field detector;

Figures 5A and 5B show exemplary magnetic field strength distributions for the configuration of Figure 4;

Figures 6A and 6B show that the exemplary arrangement of the magnet of Figure 4 provides for substantial symmetry of the magnet with respect to its magnetic axis to reduce sensitivity to inaccuracy of the magnet's alignment with the magnetic field detector;

Figures 7A and 7B show that the exemplary arrangement of the magnet of Figure 4 may also provide a reduced sensitivity to displacement of the magnet in the transverse directions;

Figure 8 is an exploded view of an embodiment of the rotational position sensor of Figure 1;

Figure 9A shows a sectional perspective view of the rotational position sensor of Figure 8;

Figure 9B shows a cross-sectional side view of the rotation position sensor of Figure 8;

Figure 10 shows a perspective view of the assembled pivot position sensor of Figure 8;

Figure 11A shows that in some embodiments, a pivot sensor housing of Figure 10 may be provided;

Figure 1 1B shows an exemplary situation where an internal component, e.g. a detection element in a pivot position sensor, may be protected by the exemplary cover of Figure 11A;

Figures 12A through 12F show various non-limiting examples of housing shapes and shield shapes that may be used;

Figure 13 shows an exemplary configuration of a system for calibrating a rotational position sensor;

Figure 14 shows an example of presenting and storing calibration data used when using a rotational position sensor;

Figure 15 shows an example calibration process that may be used;

Figure 16 shows that, in some embodiments, the pivot position sensor may include a speed determination component configured to calculate, for example, a rotational speed based on detected angular positions, and

Figures 17A and 17B show non-limiting examples of feedback controls that may be implemented using a rotational position sensor.

These and other aspects, advantages, and novel features of the present invention will become apparent upon reading the following detailed description taken with reference to the accompanying drawings. In the drawings, the same elements have the same numerical references.

The present disclosure generally relates to a rotation position sensor. As discussed herein, at least one embodiment of a rotational position sensor may have advantageous features. For example, the sensor may be configured to measure a multiple revolutions input, and the number of revolutions for such input may be selected and programmed. Accordingly, the rotational position resolution of the sensor may be adjusted from relatively low resolution to relatively high or very high resolution. In another example, the sensor may be configured to provide such functionality with the contactless arrangement of the sensing element and the sensing element. This avoids many of the mechanical problems that are usually associated with configurations where physical contact occurs.

In some embodiments of the present disclosure, the rotation sensor converts the rotational movement of a rotating object (e.g., shaft) to a translational movement of a detected element. The detection element is positioned with respect to the detected element so as to be able to determine the translational position of the detected element. In some embodiments, this translational position of the sensing element corresponds to a unique rotational position of the shaft.

In some embodiments, as shown in Figure 1, rotational position sensor 100 may include a rotating object, e.g., shaft 102, mechanically connected to carrier 104. The mechanical linkage may be configured so that rotational motion of shaft 102 is converted into translational motion of carrier 104. In some embodiments, such translational movement of media 104 may be a substantially linear movement in a direction substantially parallel to the axis of rotation of shaft 102.

In some embodiments, the mechanical connection between shaft 102 and carrier 104 may include mating screw threads formed on shaft 102 and on an interior surface of the slot defined by carrier 104. Details of such threaded connection are provided herein.

In some embodiments, the pitch of mating threads may be selected to provide a mechanical ratio between the rotation of shaft 102 and the translational movement of media 104. As used herein, the term "pitch" may be used interchangeably with the term "pitch" in assuming that the individual bolt thread examples are single threads. It should be understood that at least one feature of the present disclosure may also be applied to multiple helix threads. Therefore, where appropriate, the two terms may be distinguished throughout the specification.

As shown in Figure 1, the rotational position sensor 100 also includes a magnet 106 disposed on the carrier 104 such that it can move on the carrier 104. Detailed information is provided herein about the various orientations of the magnet 106 with respect to the direction of translational movement.

As shown in Figure 1, the rotation position sensor 100 also includes a sensing element 108 configured to detect the magnet 106 at various locations in the direction of the translational movement. This document provides details on the detection element 108.

In some embodiments, rotational position sensor 100 may also include a housing 110 to protect individual components, facilitate assembly, and the like. Details of the housing are provided herein.

Figures 2A and 2B show that, in some embodiments, rotation of the shaft 102 in the first direction (arrow 120) results in a linear movement of the carrier 104 (and magnet 106) in the first direction (arrow 122) according to the mechanical ratio between shaft 102 and carrier 104. Rotation of the shaft in the opposite direction (arrow 130) results in linear movement of the carrier 104 (and magnet 106) in a second direction (arrow 132), i.e., away from the first direction of linear movement 122.

Based on this connection between the shaft and the carrier, the range (Δα) of rotation (indicated by arrow 140) of shaft 102 may correspond to the range (ΔΥ, indicated by arrow 142) of linear motion of magnet 106 defined by the two end positions (144a, 144b) of the carrier 104. in some embodiments, the linear movement of the carrier 104 and / or the magnet 106 may be limited within the housing 110. Accordingly, the mechanical connection between shaft 102 and carrier 104 can be selected such that the range of linear motion (∆Υ) corresponding to the range of rotational motion (∆α) of shaft 102 is less than or equal to the range of mechanically limited motion of carrier 104 and / or magnet 106 .

Figure 2B shows an exemplary coordinate system where the symbol "Y" corresponds to the direction of linear motion. It should be understood that the illustrated coordinate system is simplified for the purposes of this document and does not limit the scope of this disclosure in any way.

Figure 3 shows that, in some embodiments, the rotational position sensor 100 can include various functional components. As described in Figures 1 and 2, the mechanical coupling component 156 can convert the rotational movement of the shaft (102) into a linear movement of the magnet (106), which may be matched by the magnetic component 158. The positions of the magnet can be detected by a sensor element (108), which may be represented by a field detecting component 154.

In some embodiments, rotational position sensor 100 may also include a processor component 150 and a memory component 152 that may provide at least one function as described herein. In some embodiments, the processor 150 and memory 152 may be programmable with respect to, for example, calibration and the operating dynamic range of the sensor 100.

For example, such programmability may facilitate the selection of a desired range of rotation (defined as input 160), and a shaft rotational position within such range may be determined by a unique output value within the selected output range (defined as output 170). This document provides detailed information on the programming options.

In some embodiments, the magnet 106 shown in Figures 1 and 2 may be configured in various ways. Figure 4A shows non-limiting examples of magnets that can be used with at least one embodiment of the rotational position sensor 100 herein. For example, the magnet may be cylindrical (172a, 172b, 172c) or some other shape, such as cuboid (172d, 172e, 172f). For the description of Figure 4A, it should be understood that the hatched areas and the unhashed areas represent the two poles of a dipole magnet. For example, the unhashed area may represent the North Pole, and the hatched area may represent the South Pole.

In some embodiments, the magnet 106 may be a permanent magnet. In some embodiments, the permanent magnet may be one dipole magnet or a combination of at least two dipole magnets.

For the purposes of this specification, a permanent magnet may consist of a magnet containing a magnetized material that generates its own substantially permanent magnetic field. Such materials may include ferromagnetic materials such as iron, nickel, cobalt, and some rare earth metals and some of their alloys.

For the purposes of this description, it should be understood that a single dipole magnet has the so-called "north" and "south" poles arranged such that the magnetic field lines extend from the north pole to the south pole. In the case of a single dipole magnet, its axis of magnetization is assumed to be a line drawn through the north and south poles of the magnet.

The exemplary magnet 172a is a cylindrical magnet having north and south poles along the axis of the cylinder. In such a configuration, the axis of magnetization may be approximately coaxial with the axis of the cylinder.

In another example of a cylindrical magnet 172b, the north and south poles are shown as azimuth halves of a cylinder. Hence, the axis of magnetization is likely to be approximately perpendicular to the axis of the cylinder. In the case of shaped magnets having at least two dipole magnets (e.g. 172c, 172f), the magnetization axis may or may not have a relatively simple arrangement with respect to the shape axis. For the purposes of the present description, it should be understood that the axis of magnetization may consist of the general characteristics of the magnet as well as the local characteristics of the magnetic field distribution generated by the magnet.

In some examples described herein, the axis of magnetization is shown as an axis substantially perpendicular to the direction of longitudinal movement of the magnet. However, it should be understood that other arrangements of the magnetization axis are also possible. For example, magnet configurations 172b, 172c, 172e, and 172f can have non-perpendicular magnetization axes when oriented as shown and move in a particular Y direction.

Figure 4B shows that, in some embodiments, the magnet 106 may be a permanent dipole magnet arranged with its axis of magnetization 182 substantially perpendicular to the longitudinal direction of motion of the magnet (indicated by arrow 174). For example, a cylindrical permanent magnet may be arranged such that its north and south poles substantially define an axis of magnetization 182 which is substantially perpendicular to the longitudinal direction. As discussed herein, such longitudinal movement may result from the rotation (120, 130) of the shaft 102 to which the magnet 106 is connected. According to this document, such longitudinal movement may shift the magnet 106 relative to the sensor element 108 to allow the longitudinal position of the magnet to be determined relative to the element. sensor 108.

In the example shown in Figure 4B, the axis of magnetization 182 may coincide substantially with the axis of the shape of the magnet (e.g., cylinder). The example shown in Figure 4C shows a more localized view of the magnetic field lines 180 generated by the magnet 106. While the magnet 106 shown in Figures 4C through 7B is described as a dipole magnet, such as e.g. shown in Figure 4B, it should be understood that a similar magnetic field distribution may be generated or obtained by other magnet configurations having at least one dipole magnet. Therefore, the magnetization axis 182 shown in Figure 4C may be representative of a local field affecting the sensor element 108.

In some embodiments, magnet 106 may be positioned such that its axis of magnetization 182, representative of the magnetic field at or around the sensor element 108, is substantially perpendicular to the direction of the translational movement. In some embodiments, the magnet 106 may be arranged such that the axis of magnetization and the longitudinal axis substantially define a plane that passes through the approximate center of the sensor element 108. In the context of the exemplary coordinate system shown in Figure 2B, the axis of magnetization of magnet 106 extends substantially along the Z axis in such embodiments. As discussed herein, such a configuration may provide the desired features.

Figure 4C shows a more detailed cross-sectional view of the pole of the magnet 106 with respect to a side view of the sensor element 108. As shown, the axis of magnetization 182 of the magnet 106 is shown as being substantially perpendicular to the plane defined by the sensor element 108.

The magnetic field lines 180 generated by the magnet 106 are also shown graphically. Assuming that the depicted pole is the magnetic north pole, several vectors are broken down into component vectors (BZ and BY) (in the exemplary coordinate system shown in Figure 2B). As shown, the field vectors 184 are substantially symmetrical about the magnetization axis 182. Therefore, the Z component of the field vector 184a has substantially the same direction and absolute value as the field vector 184d component and the Y component of the vector 184a has the opposite direction but substantially the same absolute value as the Y component of the vector 184d. Similarly, field vector 184b is generally a mirror image of field vector 184c.

Accordingly, the average proportion of the BZ component is substantially symmetrical about the Y = 0 axis as the magnet moves in the Y direction. Such symmetry is shown as the BZ curve 190 in Figure 5A. If the sensor element 108 measures the BZ component alone, then the determination of the magnet position may or may not be ambiguous. For example, if the sensor element 108 and the magnet 106 are configured such that the movement of the magnet is limited to one side of the longitudinal sensor element, the measured BZ component may be a component within the Y&gt; 0 portion of the curve 190. In such a situation, probably not. there will be ambiguity in determining the position based only on the BZ component. However, if the sensor element 108 and the magnet 106 are configured such that movement of the magnet is allowed on both longitudinal sides of the sensor element, there may be an ambiguous position determination problem which, however, can be resolved.

In some embodiments, the component of the magnetic field in the direction of translational motion (BY) may be measured simultaneously with the BZ component. According to the exemplary representation of the field 184 in Figure 4C, the mean BY component proportion is substantially asymmetric with respect to the Y = 0 axis as the magnet moves in the Y direction. Such asymmetry is shown as the BY curve 192 in Figure 5B. Therefore, the problem of ambiguity of the BZ component with respect to the Y = 0 axis can be solved by applying asymmetry, where BY&gt; 0, when Y&gt; 0, and BY &lt;0, when Y &lt;0.

In some embodiments, it is possible to characterize the position of the magnet in the Y direction based on the value of the BY component. However, for many reasons it may be beneficial to use the BZ component. For example, usually the most advantageous of all component detections is the detection of the perpendicular component (relative to the magnetic field detection plane). In another example, curve BY 192 goes through the zero value on the Y = 0 axis. Therefore, on the Y = 0 axis or near the Y = 0 axis, the BY component has a value of zero or a relatively small value. Consequently, the signal-to-noise ratio can be unacceptably low at the center of the magnet's Y-direction. On the other hand, the BZ component is maximal at substantially the same mid-point of the magnet's Y-movement. Moreover, the maximum value of the BZ component can typically be significantly greater than the maximum value of the BY component.

In addition to the above features, there are additional considerations whereby the exemplary magnet arrangement of Figure 4C may provide advantageous features. These features include the relative insensitivity of the output signal (170 in Figure 3) to various deviations in the arrangement of the magnet.

Figures 6A and 6B show a magnet 106 mounted on a carrier 104 as viewed along the axis of magnetization. With such an exemplary configuration, the attachment may be by a support 104 defining a recess (262 in Figure 8) that is similar in shape to at least a portion of the magnet 106 (e.g., a cylindrical recess into which a cylindrical magnet may be placed). In the context of such an exemplary mounting configuration, Figures 6A and 6B show that, because of the substantial symmetry of the magnetic field, the azimuthal alignment of the magnet 106 with respect to the magnetization axis (parallel to the Z axis in Figures 6A and 6B) does not substantially affect the magnetic field 180 acting on the component. sensor (108 in Figure 4C). An indicator 200 is provided on the magnet 106 to show the different azimuth positions.

In some embodiments, the magnet 106 is preferably mounted on the carrier 104 such that the magnetization axis of the magnet extends substantially along the Z axis and thus is perpendicular to the X and Y axis. However, the axis of magnetization may deviate from the Z axis for many reasons; examples of such deviations are shown in Figures 7A and 7B.

Figure 7A shows a side view of the magnet and carrier assembly showing that the axis of the mounted magnet 182 deviates from the Z axis (labeled 210) resulting in the magnet 106 being tilted with respect to the Y axis. Figure 7B shows an end view of the magnet and carrier assembly. which shows that the axis of the mounted magnet 182 deviates from the Z axis (labeled 210), resulting in the magnet 106 being inclined with respect to the X axis. In some embodiments, the magnet 106 may be tilted for a combination of the tilts from the X and Y axes shown in Figures 7A and 7B.

If the magnet 106 is tilted as described above, the magnetic field distributions may differ from the ideal distribution shown in Figures 5A and 5B.

Since the BZ component has a relatively high value in relation to the BY component, and the deviation angle (in relation to the Z axis) is relatively small, the total impact on the BZ component will be relatively small. Moreover, even if there will be significant variations in the BZ and / or BY components, the programmability available in some of the embodiments described herein allows for such variations to be accommodated and thus further reduces the sensitivity of the output to the orientation of the magnet.

Figures 8-10 are various views of an exemplary configuration of the pivot position sensor 100. Figure 8 is an exploded view 220, Figure 9A is a sectional perspective view of the assembled device 300, Figure 9B is a sectional side view of the assembled device 310, and Figure 10 is a perspective view of the assembled device 320 is shown.

As shown, shaft 102 has a first end 230 configured to allow torque to be transferred to shaft 102 from an external component (not shown). In the example shown, first end 230 has a groove 302 (Figure 9A) used for this purpose. It should be understood that many different configurations are possible.

Shaft 102 also has a second end 232 for engaging with carrier 104. In the illustrated example, the second end 232 of shaft 102 and a corresponding slot 260 in carrier 104 are mating threads that permit translational movement of carrier 104 in response to rotation of the shaft. 102.

The shown second end 232 of the shaft 102 is formed such that it can receive a retaining clip 256 to limit the advance of the media 104. The shown second end of shaft 232 also includes a tip 234 (Figure 9A) configured to fit into a similarly shaped recess 304 formed. in end cap 272 to secure the second end 232 of the shaft.

In the example shown, the portion between the first and second ends (230, 232) of the shaft 102 is formed to be supported in a slot 252 formed in the sleeve 250. The sleeve 250 is in turn shaped to be secured to the housing 110 by sleeves 240 and washers 254. Thus, supporting shaft 102 by sleeve 250 and a recess 304 in end cap 274 allows the shaft to rotate relatively precisely with respect to housing 110. In addition, the longitudinal movement of the shaft 102 relative to the sleeve 240 (and therefore the housing 110) is inhibited by the shim 242 and the shim 254.

In some embodiments, bushing 240 may have external screw threads to mate with mounting nut 244 to allow sensor assembly to be mounted. As shown in Figure 9B, the arrangement of the threads on the sleeve may be selected to provide an adjustable space 312 between the mounting nut 244 and the housing to allow mounting on structures of various shapes, e.g., plates. Washer 246 may also serve to enable such mounting.

In some situations, it may be desirable that the overall shape of the sensor assembly be in a specific form. For example, a rounded housing (viewed longitudinally) may be required. In particular, a round housing with respect to the longitudinal axis of the shaft may be required. However, if the inside of the housing is circular and the carrier is also circular in shape and the shaft exits from its center, the tendency of the carrier to rotate (in response to rotation of the shaft) may not be limited unless certain rotation inhibiting measures are taken. .

Therefore, in some embodiments, the side wall 270 of the housing 110 may be "U" shaped (viewed in the longitudinal direction) and the shape of the carrier may be suitably matched. In some embodiments, the curved portion of wall "U" may have a substantially half-circle shape and the longitudinal axis of shaft 102 may be centered on a circle defined by two such semi-circles. Such a configuration can meet at least part of the requirements of the aforementioned circular design. In some embodiments, the sides of the "U" wall may be extended upward to inhibit the tendency of the carrier 104 to pivot.

In some embodiments, the upper portion of "U" sidewall 270 may be substantially flat to allow a circuit assembly 280, which may be a flat printed circuit, to be mounted therein. In the example shown, circuit assembly 280 may be a substantially complete printed circuit unit dimensioned to slide into grooves 276 proximate the top of sidewall 270.

In some embodiments, as shown in Figure 8, the exemplary carrier 104 also may be "U" shaped to conform to sidewall 270 and slide longitudinally therein in response to the rotation of shaft 102. As with sidewall 270, also the upper portion of carrier 104 may be substantially flat to allow a flat circuit unit 280 to be mounted therein. The height of the "U" shape of the carrier may be selected to allow the magnet 106 (using the recess 262) to be mounted thereto at the desired distance Z (see the exemplary coordinate system in Figure 2B) from the sensing member 108.

As shown, circuit assembly 280 may include at least one electrical contact 282, which contacts may extend beyond housing 110 through suitably shaped openings in end cap 272. In some embodiments, a sealing member 274 may be provided to facilitate assembly of the rotational position sensor device. and having at least one sealing function for individual components within housing 110. The sealing element can be a gasket, epoxy, or any combination thereof.

Figure 10 shows a perspective view of the assembled pivot sensor 320. It will be appreciated that the exemplary configurations and placements of the individual components described herein allow the pivot position sensor to perform a magnetic field sensing function in a relatively simple and compact package while still meeting certain design criteria.

In some embodiments, as shown in Figures 10 and 11A, housing sidewall 270 may include grooves 324 shaped to allow easy assembly and disassembly of shield 290. In some situations, the pivot sensor may be exposed to external electric fields. and / or magnetic and / or radiation.

Since the sensor element 108 operates to detect magnetic fields, it is desirable to limit the magnetic fields to those generated by the magnet 106 to ensure accurate measurements. Therefore, in some embodiments, shield 290 may be made of a material. with relatively high magnetic permeability. For example, the sheath 290 may be made of a metal alloy, e.g., permalloy or mum metal.

As shown, cover 290 may have a shape to substantially conform to top 322 of sidewall 270. In some embodiments, cover 292 may be shaped such that its edges slide into grooves 324, including cover 290 between cover 292 and top 322 of sidewall. 270. In some embodiments, cover 292 can be formed relatively easily from plastic to conform to a shape that is more complex than that of cover 290 (and fits into grooves 324).

Under some operating conditions, the rotational position sensor may be exposed to radiation such as X-rays, gamma rays, streams of charged particles, neutron radiation, and / or other ionizing radiation. Such radiation can significantly affect at least one part of the rotational position sensor, especially in the case of a long exposure. For example, in embodiments where the sensor element 108 is made of or based on semiconductor materials and / or components, exposure to radiation may degrade the sensor properties.

Figure 1 IB illustrates that, in some embodiments, the exemplary shield 290 can provide effective protection of the sensor element 108 from radiation 328 without completely covering housing 270. In common situations where the general direction of radiation 328 is known, the rotational position sensor may be positioned such that the shield 290 protects the sensor element 108 and / or other components from radiation to reduce their exposure.

For example, it can be assumed that the pivot sensor is used to monitor the position of the movable patient platform in radiation treatment devices or imaging systems. Many of these platforms are elevated by screw jacks, and monitoring of such jacks (by a rotational position sensor) can provide information about the position of the platform. In such controlled clinical environments, the direction and amount of radiation generated by a treatment or imaging device are generally known. Therefore, the rotary position sensor (with cover) can be positioned in such a way as to provide protection against radiation.

In some embodiments, the radiation shield 290 can be shaped and sized to provide protection against specific radiation by suppressing the intensity of such radiation. Materials such as lead with heavy nuclei are suitable for shielding against X-rays and gamma rays, while low-density materials such as plastics or acrylic glass can be used against radiation generated by high energy electrons. Other materials or types of radiation are also possible.

As stated herein, the use of such easily installed and removable shields may be an advantage in terms of radiation protection. Since the internal components are protected against degrading radiation, the position sensor may have a longer service life. If it becomes necessary to replace the shield that becomes radioactive due to prolonged exposure, it can be replaced relatively easily, and the radioactive shield can be stored or disposed of easily and safely due to its relatively small size and uncomplicated shape.

Figures 12A through 12F show various non-limiting examples of a housing 270 that may be used as part of a rotational position sensor. Also provided are non-limiting examples of configurations for shield 290 having at least one feature described herein.

Figure 12A shows an exemplary configuration of housing 500 in which housing 270 includes a curved wall 502 and first and second walls 504a, 504b extending from curved wall 502, thereby forming a U-shaped wall. Examples of U-shaped wall features are described herein with reference to Figures 8 and 9.

Figure 12A also shows that, in some embodiments, the carrier 104 can have a shape substantially coinciding with the interior of the U-shaped wall and move longitudinally with respect to it. Specific features of the carrier 104 are described herein (e.g., engagement with shaft 102 and attachment of magnet 106 for longitudinal movement relative to sensor element 108).

Figure 12B shows that, in some embodiments, the curved wall may be defined by a portion of a circle 516. In an exemplary configuration of the housing 510, the curved wall may be defined by a semicircle 512 being part of the illustrated circle 516. In some embodiments, the portion of the circle defining the curved wall may be an arc extending more or less than approximately 180 degrees out of the semicircle. In the example shown in Figure 12B, the center of the circle 516 defining the semicircular wall 512 may be substantially coaxial with the center of the shaft 102.

As shown in Figure 12B, the first and second walls 514a, 514b may extend from the semicircular wall 512 to form the U-wall of the housing 270. In some embodiments, the carrier 104 may have a shape substantially to match the interior of the curved portion of the U-shaped wall. For example, the curved portion of the carrier 104 may be defined by a semicircle being part of the circumscribed circle 518 to conform to the exemplary semicircular wall 512.

Figures 12C and 12E show that the upper portion of the U-shaped housing can be configured in a number of different ways. The exemplary configuration 520 of Figure 12C shows that the closure wall 524 can be joined to the side walls (e.g., 514a, 514b in Figure 12B) so as to form substantially square corners shown as 522a and 522b. Another exemplary configuration 540 of Figure 12E shows that the closure wall 544 can be joined to the side walls (e.g. 514a, 514b in Figure 12B) so as to form the rounded corners shown as 542a and 542b.

Figures 12D and 12F show that a cover 290 for at least one function described herein may be configured in a variety of ways. The exemplary configuration 530 of Figure 12D shows that the cover 290 can follow the exemplary square shape (522a, 522b) of the upper housing portion of Figure 12C such that the cover 290 has substantially square corners defined as 532a and 532b. Another exemplary configuration 550 of Figure 12F shows that the shield 290 may follow the exemplary round shape (542a, 542b) of the upper housing portion (542a, 542b) of the upper housing portion of Figure 12E such that the shield 290 has substantially rounded corners defined as 552a and 552b.

For the purposes of Figures 12A through 12F, it should be understood that terms such as "top" or "side" are used in the context of the relative positions of various parts of the U-shaped wall and do not imply that the pivot position sensor as a whole should be positioned in this manner. . For the sake of clarity, it should be understood that in the case of embodiments with a U-shaped housing, the sensor may be arranged in any required or desired manner (e.g. U-arms pointing up, down, sideways, or any combination of these directions).

As described herein with reference to Figure 3, some embodiments of the rotational position sensor 100 may include a programming function with respect to, for example, calibration and the working dynamic range of the sensor 100. Figures 13 and 14 show examples of such programming possibilities.

The calibration circuit 330 shown in Figure 13 may include a controller 332 in communication (indicated by line 334) with actuator 336 to allow controlled rotation (arrow 338) of shaft 102. In response to controlled rotation (e.g., steps), magnet 106 moves relative to the member. sensor 108 over a selected range of longitudinal movement (designated 350) within housing 110. In all controlled positions of the magnet, the output signal can be received via contacts 282 via connector 342; such a signal may be passed (line 340) to controller 332 for processing.

The calibration data 360 obtained as follows may be presented in a variety of ways. As shown in the exemplary representation 360 in Figure 14, a relationship between an output signal, e.g., voltage, and an input signal, e.g., angular position?, Can be derived. Due to multiple calibration data points 362 obtained for multiple angular positions (e.g., in increments of fit a curve, such as straight line 380, to reflect the relationship between the output voltage and the input angular position. Fitting such a representative curve can be achieved in a number of commonly known ways.

In some situations, certain sets of calibration data points may deviate systematically from the representative curve. For example, data points near the upper limit of angular position a are shown deviating from line 380 (representing the greater part of the angular range). Such deviations can occur for many reasons. For the purposes of this document, the systematic deviations are shown as the deviation curve 370.

In some embodiments, at least one correction may be made to adjust the output signal to obtain the desired representation of the output signal. For example, the systematic deviation 370 can be adjusted (arrow 372) such that the output voltage can be represented as a substantially linear relationship over the defined range of angular position α.

In some embodiments, information about the calibrated input to output relationship may be recorded to be reproduced during operation of the rotational position sensor 100. For example, such information may be stored on the memory component 150 of Figure 3 in one of a number of formats, e.g. an array, one or more parameters (e.g. parameters of the slope and point of intersection in the case of a linear relationship) for an algorithm representative of the relationship, etc.

Figure 15 shows an exemplary process 400 that may be used to achieve at least one feature of the calibration process described with reference to Figures and 14. In process block 402, angular position sensor shaft 100 may rotate to a first position (on) corresponding to a first limit ( e.g., a lower limit) of the desired range of rotation. Process 400 may then introduce an iterative sequence where the measurements are made in incremental steps. Therefore, in decision block 404, process 400 determines whether the current angular position a is less than the second position (a ') corresponding to the second limit (e.g., upper limit) of the desired range of rotation. If the answer is "Yes", process 400 continues with another iterative measurement. In process block 406, a calibration measurement can be made at the current position of shaft a. In process block 408, the position of the shaft may be incrementally changed by Δα, and process 400 may perform a test of decision block 404 with the current angular position.

If the answer is "No" in decision block 404, a systematic correction (if required) can optionally be made in process block 410. In process block 412, a representative output response (e.g., a linear output response) can be obtained. In process block 414, information on the representative output response may be recorded in a manner that is reproduced during operation of the angular position sensor 100.

In some embodiments, the calibration function may include a lockout function to prevent unauthorized calibration and / or modification of the response output information. In some situations, this lockout may be applied after the calibration process has been performed by an authorized facility, such as a calibration facility.

In some situations, it may be desirable to provide at least some ability to adjust, adjust, etc. after locking the calibration function and / or calibration data. In some embodiments, the calibration function may include a key (e.g., electronic key) that allows an authorized subject to unlock at least some of such functions. Locking, unlocking, and operations related to the description below can be performed in known ways.

In the following description referring to Figures 13 to 15, the linear relationship between the output and input signals is characterized, which is one of many possible relationships. In some embodiments, such a linear relationship may be derived from the translational position of the magnet relative to the sensing element 108.

In some embodiments, the detection element 108 may be an integrated circuit capable of detecting three components (BX, BY, BZ) of the magnetic field. Such an integrated circuit (IC) may, for example, comprise a monolithic Hall detection IC (model MLX90333) manufactured by Melexis Microelectronic Systems. Additional information on an example of an IC-based sensing element can be found in the documentation (including application) available at http://melexis.com.

In the case of sensor elements equipped with the function of detecting at least two components of the magnetic field (e.g. Melexis sensor), the combination of the BZ component and the longitudinal component (e.g. BY) allows to obtain a quantity with an approximately linear relationship to the longitudinal position of the magnet (relative to the sensor element). For example, Θ = arctan (BY / BZ) (Θ is defined as shown in Figure 4C) may provide an approximately linear response to the longitudinal position of the magnet in the Y direction.

In some embodiments, such an approximately linear relationship between an exemplary amount θ and a position Y may be used to obtain an approximately linear relationship between an amount θ and the angular position (a) of the shaft.

Such a derivation of the relationship poses no problems since the angular position (a) of the shaft is essentially characterized by a linear relationship to the translational movement of the magnet carrier connected by substantially uniform threads.

In some embodiments, the linear relationship between the angular position (a) of the shaft and the magnitude of the magnetic field θ may additionally be characterized by an amplitude parameter that allows the desired output range to be selected. For example, the amplitude parameter may be selected to produce outputs ranging from 0 to 5 volts.

While the following example is described in the context of a substantially linear property that may result from a combination of magnetic field components, it should be understood that the detected quantities need not necessarily be linear from the outset. For example, the BY and / or BZ components described with reference to Figure 5 may be linearized by using commonly known techniques with respect to calibration data points and / or representative curves.

In some embodiments, the output from rotational position sensor 100 need not even be a linear response to the input rotation. Preferably, however, each angular position of the shaft has a unique corresponding output value.

In various examples described herein, the output of the rotational position sensor 100 is sometimes voltage. However, it should be understood that the output signal may take various forms. The output signal can be digital or analog and include, inter alia, signals based on pulse width modulation or serial protocol.

In some embodiments, the output of rotational position sensor 100 may be in a processed format. Such processing may be, for example, amplification and / or analog-to-digital conversion.

In some embodiments, detecting the translational position of the magnet (and thus the angular position of the shaft) may determine the rate of such position changes. Accordingly, as shown in Figure 16, sensor system 420 may include a position determination component 422 with the features described herein, and optionally a speed determination component 424. In some embodiments, the speed determination component may allow the average or approximate instantaneous shaft rotation speed to be determined from position measurements performed as described herein and time information (e.g., sampling period). In some embodiments, an estimated angular acceleration of the shaft may be derived from such a speed determination.

Figures 17A and 17B are schematic illustrations of non-limiting examples of systems in which the rotational position sensor may be used. In one exemplary system 430 shown in Figure 17A, a rotational position sensor 440 may be positioned between an actuator 432 and a controlled device 444 driven mechanically by actuator 432 via mechanical linkage 436. For this reason, the mechanical output element (arrow 434) of the actuator 432 can be connected (arrow 438) to a sensor 440 (e.g. by a shaft), such mechanical control being transferred to the sensor 440 and transferred (arrow 442) to the device to be controlled. 444.

The sensor 440 can operate as described herein to enable, e.g., determination of a rotational state of a mechanical connection (e.g., a rotational position of a shaft). As shown, sensor 440 can communicate with a controller 450 that controls (line 452) actuator 432 in response to an output from the sensor. In some embodiments, such actuator detection and control system 432 (and therefore controlled device 444) may be configured as a feedback control system.

Figure 17B shows another example of a system 460, which may be a variation of the system of Figure 17A. In an exemplary configuration 460, a mechanical coupling component 466 may be coupled to a mechanical output member (arrow 464) from an actuator 462 and provide separate mechanical outputs 472 and 468. Output 472 may be connected to a controlled device 474 and output 468 may output to a sensor 470. Similar to example 430 of Figure 17A, sensor 470 may have an output 434 to a controller 480 that controls (line 482) actuator 462.

Likewise, such actuator sensing and control system 462 may be configured as a feedback control system.

As described with reference to Figures 17A and 17B, the exemplary configuration 430 may be considered an embedded monitoring system and the exemplary configuration 460 may be considered a parallel monitoring system. Other configurations of monitoring systems and / or feedback signals are also possible.

In at least one embodiment, the functions, methods, algorithms, techniques, and components described herein may be implemented in hardware, in software, in firmware (e.g., with code segments), or any combination thereof. When implemented in software, the functions may be written or transmitted as one or more instructions or code on a computer readable medium. Tables, data structures, formulas, etc. can be written on a computer readable medium. The computer readable medium may be a computer storage medium or a communication medium, including any medium that allows a computer program to be transferred between different locations. The data carrier can be any available medium that is supported by a general purpose or special purpose computer. By way of non-limiting example, such computer-readable medium may be RAM, ROM, EEPROM, CD-ROM or other optical disk, magnetic disk or other magnetic storage device, or any other medium. which can be used to carry or save the desired program code in the form of instructions or data structures, and which can be operated by a general purpose or special purpose computer or general purpose or special purpose processor. A computer-readable medium may also be referred to as any communication method. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, optical fiber, twisted-pair cable, digital subscriber line (DSL), or wireless technologies such as infrared, radio waves, or microwave, then coaxial cable, optical fiber , twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio waves or microwaves also meet the definition of a carrier. The terms "discs" and "discs" used in this documentation refer to compact disc (CD), laser disc, general purpose digital disc (DVD), flexible disc and blu-ray disc, with discs generally playing back data magnetically and the discs optically with a laser. Combinations of the foregoing media are also included within the scope of a computer-readable medium.

In a hardware implementation, at least one processing unit in the transmitter and / or receiver may be implemented in the at least one computing device, including but not limited to specialized integrated circuits (ASIC), digital signal processors (DSP), digital signal processing devices (DSPD), programmable logic devices (PLD), programmable logic devices (FPGA), processors, drivers, microcontrollers, microprocessors, electronic devices, other electronic units used to perform the described functions or their combinations.

In the case of a software implementation, the techniques described herein may be implemented with code segments (so-called modules) that perform the described functions. Software codes can be saved in memory units and executed by processors. The memory unit may be implemented within the processor or external to the processor, in the latter case it may be coupled to and communicate with the processor via various means known in the art. The segment code may correspond to a procedure, function, subroutine, program, repeating program, repeating subroutine, module, software package, class, or any combination of instructions, data structures, or program declarations. A code segment may be coupled to another code segment or hardware circuit by transmitting and / or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. may be uploaded, transferred, or transferred by any appropriate means, including memory sharing, messaging, token transfer, network transmission, etc.

While the above-disclosed embodiments have demonstrated, described, and demonstrated significant novel features of the invention with respect to the above-disclosed embodiments, it should be recognized that various omissions, substitutions, and modifications in the detailed device form of the systems and / or methods set forth herein can be made by those skilled in the art. in the field of interest without departing from the scope of the present invention. Consequently, the scope of the present invention cannot be limited to the above description, but should be defined by the appended claims.

All publications and patent applications mentioned in this specification indicate the level of knowledge of the art by those skilled in the art to which the present invention pertains.