Stator device for a displacement system

Abstract

Aspects of the present disclosure provide a stator device for a displacement system. The stator device may include a stator including at least one conductor positioned to generate at least one external magnetic field operable to move at least one mover in a working environment of the displacement system. The stator device may also include an enclosure non-releasably surrounding the stator and isolating the stator from an external environment comprising the working environment. The stator device may also include a coating adhered to the stator and isolating the stator from the external environment comprising the working environment.

Description

[0001] STATOR DEVICE FOR A DISPLACEMENT SYSTEM

[0002] CROSS-REFERENCE TO RELATED APPLICATION

[0003] This application claims the benefit of and priority from United States provisional patent application no. 63 / 678,969, filed August 2, 2024, the entire contents of which are incorporated by reference herein.

[0004] FIELD

[0005] This disclosure relates generally to displacement systems or conveyors and stator devices for such systems.

[0006] BACKGROUND

[0007] Displacement systems, or conveyors, such as XY tables and rotary tables may be used in various manufacturing, inspection, and assembling processes. These systems may include a stator and a mover, typically referred to as a robotic device, mover device, or moveable stage. The stator actuates the mover. XY motion may be achieved by stacking two linear stages (e.g., a X-stage and a Y-stage) together via connecting bearings. Alternatively, a single moving stage capable of XY motion may be used, eliminating additional bearings. It may also be desirable for such a moving stage to be able to provide at least some Z motion.

[0008] Attempts have been made to design displacement systems using the interaction between current-carrying coils and permanent magnets. Examples include: US patent No. 6,003,230; US patent No. 6,097,114; US patent No. 6,208,045; US patent No.6, 441,514; US patent No. 6,847,134; US patent No. 6,987,335; US patent No. 7,436,135; US patent No. 7,948,122; US patent publication No. 2008 / 0203828; W.J. Kim and D.L. Trumper, High- precision magnetic levitation stage for photolithography. Precision Eng. 22 2 (1998), pp. 66- 77; D.L. Trumper, et al, “Magnet arrays for synchronous machines”, IEEE Industry Applications Society Annual Meeting, vol. l, pp. 9 - 18, 1993; and J.W. Jansen, C.M.M. van Lierop, E.A. Lomonova, A. J. A. Vandenput, “Magnetically Levitated Planar Actuator with Moving Magnets”, IEEE Tran. Ind. App.,Vol 44, No 4, 2008.

[0009] More recent techniques for implementing displacement systems having a mover and a stator are described in: PCT application No. PCT / CA2012 / 050751 (published under WO / 2013 / 059934) entitled DISPLACEMENT DEVICES AND METHODS FOR FABRICATION, USE AND CONTROL OF SAME; PCT application No. PCT / CA2014 / 050739 (published under WO / 2015 / 017933) entitled DISPLACEMENT DEVICES AND METHODS AND APPARATUS FOR DETECTING AND ESTIMATING MOTION ASSOCIATED WITH SAME; PCT application No. PCT / CA2015 / 050549 (published under WO / 2015 / 188281) entitled DISPLACEMENT DEVICES, MOVEABLE STAGES FOR DISPLACEMENT DEVICES AND METHODS FOR FABRICATION, USE AND CONTROL OF SAME; PCT application No. PCT / CA2015 / 050523 (published under WO / 2015 / 184553) entitled METHODS AND SYSTEMS FOR CONTROLLABLY MOVING MULTIPLE MOVEABLE STAGES IN A DISPLACEMENT DEVICE; and PCT application No. PCT / CA2015 / 050157 (published under WO / 2015 / 179962) entitled DISPLACEMENT DEVICES AND METHODS FOR FABRICATION, USE AND CONTROL OF SAME.

[0010] However, existing displacement systems may lack certain functionality and performance. For example, stators of existing systems may not be adequately protected from adverse environmental conditions, may themselves contaminate environments in which they operate, or may undergo other undesirable interactions with their surroundings.

[0011] SUMMARY

[0012] Embodiments of the present disclosure may provide stator devices in which a stator is isolated from an external environment by a barrier such as a non-releasable enclosure and / or a coating.

[0013] According to at least one embodiment, there is disclosed a stator device for a displacement system, the stator device comprising: a stator comprising at least one conductor positioned to generate at least one external magnetic field operable to move at least one mover in at least two degrees of freedom in a working environment of the displacement system; and an enclosure non-releasably surrounding the stator and isolating the stator from an external environment comprising the working environment.

[0014] In some embodiments, the enclosure surrounds the stator from all sides of the stator. In some embodiments, the enclosure defines a stator environment containing the stator; and a pressure in the stator environment is different from a pressure in the working environment.

[0015] In some embodiments, the pressure in the stator environment is greater than the pressure in the working environment.

[0016] In some embodiments, the pressure in the stator environment is about 1 atmosphere greater than the pressure in the working environment.

[0017] In some embodiments, the enclosure comprises a plurality of enclosure portions joined together.

[0018] In some embodiments, the plurality of enclosure portions is joined together by at least one weld.

[0019] In some embodiments, the plurality of enclosure portions comprises a first enclosure portion and a second enclosure portion; and a portion of the second enclosure portion is between the stator and a portion of the first enclosure portion.

[0020] In some embodiments, the enclosure is fixed to the stator.

[0021] In some embodiments, the enclosure is fixed to the stator by an adhesive.

[0022] In some embodiments, the enclosure is fixed to the stator by a viscous fluid.

[0023] In some embodiments, the enclosure is fixed to the stator by a mechanical interlock.

[0024] In some embodiments, the enclosure is fixed to the stator by a vacuum formed between the enclosure and the stator.

[0025] In some embodiments, the enclosure is fixed to the stator by a weld.

[0026] In some embodiments, the enclosure is electrically conductive.

[0027] In some embodiments, the enclosure has no discontinuity in electrical conductivity larger than 1 cm.

[0028] In some embodiments, the enclosure defines an enclosure service opening dimensioned to received therethrough one or more utility service conduits associated with the stator.

[0029] In some embodiments, the enclosure comprises stainless steel.

[0030] In some embodiments, the stator is surrounded by the stainless steel of the enclosure.

[0031] In some embodiments, the enclosure comprises a coating adhered to the stator. According to at least another embodiment, there is disclosed a stator device comprising: a stator comprising at least one conductor positioned to generate at least one external magnetic field operable to move at least one mover in a working environment of the displacement system; and a coating adhered to the stator, the coating isolating the stator from an external environment comprising the working environment.

[0032] In some embodiments, the at least one external magnetic field is operable to move the at least one mover in at least two degrees of freedom in the working environment.

[0033] In some embodiments, the coating surrounds the stator.

[0034] In some embodiments, the coating surrounds the stator from all sides of the stator.

[0035] In some embodiments, the coating seals the stator from the working environment.

[0036] In some embodiments, the coating is airtight.

[0037] In some embodiments, the coating is electrically conductive.

[0038] In some embodiments, the coating has no discontinuity in electrical conductivity larger than 1 cm.

[0039] In some embodiments, the coating is non-porous.

[0040] In some embodiments, the coating is non-volatile.

[0041] In some embodiments, the coating is non-absorptive.

[0042] In some embodiments, the coating is smooth.

[0043] In some embodiments, the coating defines a coating service opening dimensioned to received therethrough one or more utility service conduits associated with the stator.

[0044] In some embodiments, the coating comprises a polymer coating.

[0045] In some embodiments, the coating comprises a ceramic.

[0046] In some embodiments, the coating comprises a metal.

[0047] In some embodiments, the coating comprises carbon.

[0048] In some embodiments, the external environment further comprises a non-working environment, the stator between the working environment and the non-working environment at least when the at least one mover is moving in the working environment in response to the at least one external magnetic field.

[0049] In some embodiments, the stator device isolates the working environment from the non-working environment. In some embodiments, the stator device seals the working environment from the nonworking environment.

[0050] In some embodiments, the stator further comprises at least one sensor positioned to measure at least a magnetic field from at least one magnet of the at least one mover when the at least one mover is positioned within a sensor range of the at least one sensor.

[0051] In some embodiments, the stator further comprises a driving circuit operable to drive at least one electrical current in the at least one conductor to cause the at least one conductor to generate the at least one external magnetic field.

[0052] In some embodiments, the stator device further comprises a controller configured to control the driving circuit to drive the at least one electrical current in the at least one conductor in response to at least the magnetic field measured by the at least one sensor.

[0053] Other aspects and features will become apparent to those ordinarily skilled in the art upon review of the following description of illustrative embodiments in conjunction with the accompanying figures.

[0054] BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive.

[0056] FIG. 1 is a is a front section view of a displacement system according to one embodiment.

[0057] FIG. 2 is a front section view of a displacement system according to another embodiment.

[0058] FIG. 3 is a front section view of a displacement system according to another embodiment.

[0059] FIG. 4 is a front section view of a displacement system according to another embodiment.

[0060] FIG. 5 is a front section view of a displacement system according to another embodiment. DETAILED DESCRIPTION

[0061] Manufacturing, assembly, and inspection systems may use displacement systems, or conveyors, to transport components to be processed, combined, and packaged. Electromagnetic planar motors may be used as displacement systems in such applications. An electromagnetic planar motor generally includes one or more movers for holding components and one or more stators for supporting and driving / actuating the movers. The one or more stators may be incorporated into a stator device, which may further include additional elements such as support structures, enclosures, coatings, utility conduits, and / or protective covers. Described herein are stator devices which include a non-releasable / non-removable barrier around a stator which isolates the stator from an external environment.

[0062] Referring to FIG. 1, a displacement system according to one embodiment is shown generally at 100 and includes a mover 102, a stator device 104, and a controller 106. The mover 102 may be configured to carry one or more components (not shown). The mover 102 may also be referred to as a “mover device”, a “robotic device”, a “moveable stage”, a “motion stage”, or a “moveable motion stage”. Further, as used herein, the term “component” is a general term and non-limiting examples of components that may be carried by the mover 102 may include workpieces, products being assembled, raw parts, materials, samples, biological samples, drugs, containers, payloads, devices, and assemblies. In the embodiment shown, the displacement system 100 includes only one mover 102. However, alternative embodiments may include multiple movers, and in some alternative embodiments, a plurality of movers may carry a holder which may hold one or more components. In some systems, all movers are substantially similar or nearly identical. However, other systems may include movers of varying sizes and configurations.

[0063] The stator device 104 includes a stator 108 and an enclosure 110 for the stator 108, and generally supports and actuates the mover 102, such that the mover 102 travels across the stator device 104 to another location in displacement system 100. In the embodiment shown, the displacement system 100 includes only the one stator device 104, and the stator device 104 includes only the one stator 108. However, alternative embodiments may include multiple stator devices, and may include stator devices incorporating multiple stators. In some alternative embodiments, the multiple stators and / or stator devices may be of different types - for example, in some alternative embodiments, some stator devices may have large work areas, while other stator devices may function as flyways between the work areas for rapid movement of movers and components in narrow spaces. This may be achieved by arranging a stator made from multiple electromagnetic driving regions, arranged in a single row in the direction of movement of the mover.

[0064] The controller 106 controls the stator 108 and the mover 102. The controller 106 may be directly connected to the stator 108 using a wired or wireless connection, and may control the mover 102 indirectly through the stator 108. Alternatively, the controller 106 may also be connected to the mover 102 using a wired or wireless connection, such that the controller 106 may communicate with the mover 102 directly. For example, a high speed data cable may be used, such as an ethernet cable, a HDMI cable, or any cable of sufficient data rate bandwidth. In some embodiments, the controller 106 may be completely integrated with the stator 108 within the stator device 104. In embodiments where the controller 106 is completely integrated within the stator device 104, any method of electrical connection may be used, such as ribbon cables, edge board connectors, wire connectors, headers and pins, etc. A wireless connection may include Bluetooth®, WiFi, Zigbee®, Cellular, Near Field Communications (NFC), etc. In some embodiments, more than one controller may be used within the displacement system 100. For example, the controller 106 may only control the stator 108 or a group of stators including the stator 108, while another controller may control another stator or group of stators.

[0065] Generally, the mover 102 and the stator 108 may interact with each other via one or more magnetic fields, so that the stator 108 can provide forces and torques to the mover 102 to controllably move the mover 102. The controller 106 may determine and provide commands to the stator 108 to generate specific forces and torques to move the mover 102.

[0066] A pair of coordinate systems may be defined to help explain the movement of the mover 102 relative to the stator 108 and, more generally, the stator device 104. In particular, a stator coordinate system may be defined, which is fixed to the stator 108. A mover coordinate system may also be defined, which is fixed to the mover 102 and moves with the mover 102 relative to the stator 108 and the stator coordinate system. Conventional Cartesian coordinates (x, y, z) may be used to describe these coordinate systems, although it will be appreciated that other coordinate systems could be used. For convenience and brevity, in the present description and the associated drawings, the directions (e.g., x, y, z directions) in the stator coordinate system and the directions in the mover coordinate system may be shown and described as being coincident with one another - i.e., the stator-x (or Xs), stator-y (or Ys), and stator-z (or Zs) directions may be shown as coincident with mover-x (or Xm), mover-y (Ym), and mover-z (or Zm) directions, respectively. Accordingly, reference to directions x, y, and / or z may refer to directions in both or either of the stator and mover coordinate systems. However, it will be appreciated from the context herein that in some embodiments and / or circumstances, the mover 102 may move relative to the stator 108 such that these stator and mover coordinate systems are no longer coincident with one another. In such cases, the following convention may be adopted: the terms stator-x, stator-y and stator-z may be used to refer to directions and / or coordinates in the stator coordinate system and the terms mover-x, mover-y and mover-z may be used to refer to directions and / or coordinates in the mover coordinate system. The symbols Xm, Ym, and Zm may be used to refer respectively to the mover-x, mover-y and mover-z directions, the symbols Xs, Ys, and Zs may be used to refer respectively to the stator-x, stator-y and stator-z directions and the symbols X, Y, and Z may be used to refer respectively to either or both of the mover-x, mover-y, and mover-z and / or stator-x, stator-y, and stator-z directions. In some embodiments, during normal operation, the mover-z and stator-z directions are approximately in the same direction (e.g. within ±30° in some embodiments; within ±10° in some embodiments; and within ±2° in some embodiments).

[0067] The mover 102 includes a structural frame 112 and one or more actuation magnets 114 fixed to the structural frame 112. The structural frame 112 may be used to provide support to the magnets, facilitate bonding, and / or provide an interface for a part, fixture, or tooling. In some embodiments, the structural frame 112 may optionally be used to mount additional mounting or locating features (not shown). The one or more actuation magnets 114 may also be referred to as an “actuation magnet assembly” or, more generally, a “magnet assembly”. The one or more actuation magnets 114 may be, for example, permanent magnets. In some embodiments, the one or more actuation magnets 114 may include a plurality of magnetization regions, each magnetization region having a respective magnetization direction. In FIG. 1, the mover 102 is shown as including a single actuation magnet 114. However, in some embodiments, the mover 102 may include more than one actuation magnet 114, that is, the mover 102 may include a plurality of actuation magnets 114. In such embodiments, one, some, or all of the plurality of actuation magnets 114 may be fixed to the structural frame 112. The one or more actuation magnets 114 are configured to respond to one or more external magnetic fields, and in particular are configured to generate forces for moving the mover 102 in response to one or more external magnetic fields. Examples of such actuation magnets are described and illustrated in United States patent no. US 10,222,237 (incorporated herein by reference) as arrays of permanent magnets 112A, 112B, 112C, 112D (or collectively, magnet arrays 112).

[0068] Still referring to FIG. 1, the stator 108 includes sensors 116, electrical conductors 118, and an amplifier 120. In some embodiments, at least the electrical conductors 118, and possibly also the sensors 116, may collectively be referred to as a “stator motor board”. Each of the sensors 116 is configured to measure at least one magnetic field, such as a magnetic field from the one or more actuation magnets 114 of the mover 102. Each of the sensors 116 may only accurately measure a magnetic field within a certain range of that sensor 116. Examples of such sensors are described and illustrated in United States patent no. US 10,222,237 as magnetic field sensors 501. The sensors 116 may include, for example, Halleffect magnetic field sensors, magneto-resistive sensors, and / or other suitable types of magnetic field sensors that can measure magnetic flux density. In FIG. 1, the stator 108 is shown as including three sensors 116; however, it will be appreciated that in some embodiments, the stator 108 may include only one sensor 116, or two sensors 116, or more than three sensors 116. These sensors 116 may also be arranged at positions extending along the Y direction in addition to different X positions that are shown in FIG. 1.

[0069] Each of the electrical conductors 118 is configured to generate at least one external magnetic field. The electrical conductors 118 may be, for example, coils. Examples of such coils are described and illustrated in United States patent no. US 10,222,237 as coil traces 126. In FIG. 1, the stator 108 is shown as including four electrical conductors 118; however, it will be appreciated that in some embodiments, the stator 108 may include only one electrical conductor 118, two electrical conductors 118, three electrical conductors 118, or more than four electrical conductors 118. In some embodiments, the stator 108 may include a plurality of electrical conductors distributed in one or more planar layers. In some embodiments, the layout of the electrical conductors 118 may include a first group of coils that are linearly oriented and / or elongated in a first direction (e.g., the X-direction as shown in FIG. 1). The first group of coils may also include a second coil pitch or spacing in a second direction (e.g., the Y-direction as shown in FIG. 1). The electrical conductors 118 may also include a second group of coils that are linearly elongated in the second direction. The second group of coils may also include a first coil pitch or spacing in the first direction. The first and second coil pitch / spacing may be equal. In some embodiments, the electrical conductors 118 may be linearly elongated in different directions (e.g., linearly elongated in the X-direction or linearly elongated in the Y-direction) and may vertically overlap with other electrical conductors.

[0070] The sensors 116 and electrical conductors 118 may be arranged in a pattern on the stator 108, for example as described and illustrated in United States patent no. US 10,222,237. Patterns may include one or more sensors 116 configured around each of the electrical conductors 118, such as one of the sensors 116 at each edge of one of the electrical conductors 118. Other patterns may also be possible. It will be appreciated that the sensors 116 may be arranged in patterns near or around the electrical conductors 118 to provide proper feedback to the controller 106 for position sensing and control of the mover 102, for example. In some embodiments, the stator device 104 may further include a plurality of iron teeth (not shown).

[0071] The amplifier 120 is connected to the electrical conductors 118. In some embodiments, the amplifier 120 may be referred to as a “driving circuit” or a “stator driving circuit”. In general, the amplifier 120 may drive one or more electrical currents in the electrical conductors 118, generating one or more external magnetic fields. The controller 106 may be connected to deliver control signals to the amplifier 120. The control signals may be used to control current driven by the amplifier 120 into the electrical conductors 118. In the embodiment shown in FIG. 1, the stator 108 includes one amplifier 120. However, in alternative embodiments, a stator may include more than one amplifier.

[0072] The current controllably driven into each of the electrical conductors 118 may cause that electrical conductor 118 to create or generate at least one external magnetic field. The at least one external magnetic field thus generated causes corresponding magnetic forces to act on the mover 102. The one or more external magnetic fields may act on the one or more actuation magnets 114, thereby moving the mover 102 relative to the stator 108 and thus the stator device 104. The mover 102 may be controllable in at least two degrees-of-freedom (2- DOF) motions, including but not limited to three in-plane degrees-of-freedom (3 -DOF) controllable motions and six degrees-of-freedom (6-DOF) controllable motions, which may include three translational degrees of freedom and three rotational degrees of freedom, for example. In general, embodiments such as those described herein may involve one or more movers that are controllably movable relative to a stator in at least 2 in-plane DOF motions, in 3 in-plane DOF motions, in 4 DOF motions, in 5 DOF motions, or in 6-DOF controllable motions, for example.

[0073] As noted above, the stator device 104 includes an enclosure 110 for the stator 108. In the embodiment shown in FIG. 1, the enclosure 110 surrounds the stator 108 and may function as a barrier between the stator 108 and at least a working environment of the mover 102, shown generally at 122, thus isolating the stator 108 from at least the working environment 122. The working environment 122 is generally a space in which the mover 102 moves during operation - that is, when being controlled by the stator 108, e.g., when carrying a component. In some embodiments, the 110 may protect the stator 108 from adverse conditions in the working environment 122, such as humidity, liquids, and / or corrosive environments. In some embodiments, the enclosure 110 may protect the working environment 122 from contamination (e.g., from the stator 108).

[0074] The enclosure 110 of the stator device 104 includes a working surface 124 for the mover 102 to move upon. Generally, the working surface 124 describes a continuous area of the enclosure upon which the mover 102 may be controlled by the stator 108. Suitable feedback control algorithms executed by the controller 106 and suitable position feedback from the sensors 116 allow the controller 106 and the stator 108 to move and control the mover 102. The working surface 124 may be flat, curved, cylindrical, spherical or some other shape that allows the mover 102 to move along the working surface 124. In some embodiments, a combined working surface may be defined by a plurality of stators or stator devices, such that each working surface of each stator / stator device may be combined into a larger combined working surface. While the working surface 124 is depicted horizontally in FIG. 1, it should be understood that the working surface 124 can be mounted vertically or at an angle to gravity.

[0075] In general, under the control of the controller 106, the mover 102 may move along the working surface 124 in a “contact mode” or a “non-contact mode”. The contact mode (also known as “sitting mode”) may involve contact media such as sliding and / or rolling bearings. The non-contact mode (also known as “levitation mode”) may require maintaining a controllable gap 126 between the mover 102 and the working surface 124 of the enclosure 110 in a normal direction Z. The gap 126 may be an air gap. The mover 102 may also rest upon the working surface 124 without moving, which may be in a contact mode or a non-contact mode. In the non-contact mode, the mover 102 may have six degrees-of-freedom (6-DOF) controllable motion (known as “active levitation mode”). Alternatively, the mover 102 may maintain the gap 126 by passive levitation means (known as “passive levitation mode”). In the passive levitation mode, the mover 102 may rest above the working surface 124 in the noncontact mode.

[0076] In some embodiments, the magnetic forces associated with the interactions between the magnetic fields created by the currents in the electrical conductors 118 and the magnetic fields associated with the one or more actuation magnets 114 may attract the mover 102 toward the stator 108, and thus the working surface 124, at all times when the controller 106 is controlling the currents driven by the amplifier 120. In other embodiments, the magnetic forces associated with the interactions between the magnetic fields created by the currents in the electrical conductors 118 and the magnetic fields associated with the one or more actuation magnets 114 may force the mover 102 away from the stator 108, and thus the working surface 124, in order to balance gravitational forces to maintain the gap 126 at all times.

[0077] In some embodiments, the gap 126 between the mover 102 and the working surface 124 may be maintained by air bearings or compressed-fluid bearings. It will be appreciated that in some embodiments, the gap 126 may be zero, such as when the mover 102 operates in contact mode. Contact mode may involve contact media such as sliding and / or rolling bearings between mover 102 and working surface 124.

[0078] As described above, the mover 102 may work in “levitation mode”, being levitated near the working surface 124 of the enclosure 110 without contacting the enclosure 110. In levitation mode, the mover 102 may move along the working surface 124 in X and Y directions, where X and Y are two non-parallel (e.g., orthogonal) directions inside the working surface 124. It will be appreciated that the gap 126 between the working surface 124 and a bottom surface of the mover 102 is generally much smaller than the mover’s lateral dimensions (i.e., dimensions in the X and Y directions).

[0079] Although the mover 102 may generally be capable of 6-DOF controllable motion, such functionality may not be necessary in all situations. In certain embodiments, levitation of the mover 102 may not be needed and heavy load carrying capability of the mover 102 may be desirable. In such embodiments, the mover 102 may sit on the working surface 124 supported with mechanical bearings (for example, planar sliding bearings and / or ball transfer units), and may be capable of in-plane 3-DOF controllable motion: translation in X and Y and rotation around Z, where X and Y are two non-parallel (e.g., orthogonal) directions in working surface 124 and Z is a direction normal to the working surface 124. When the mover 102 relies on sliding and / or rolling bearings for support on the working surface 124 and the mover 102 is capable of 3-DOF controllable motion, it may be referred to as working in “3-DOF controlled sitting mode”.

[0080] In some embodiments, the mover 102 may be capable of in-plane 3-DOF controllable motions (translations in X and Y and rotation around Z) working in levitation mode without contact with working surface 124. In this mode, the translation in Z, rotation around X, and rotation around Y (and thus the associated degrees-of-freedom) of the mover 102 may be open-loop controlled without feedback, using suitable passive levitation technology. When the mover 102 is capable of 3-DOF controllable motion without contact with the stator device 104, it may be referred to as working in “3-DOF controlled levitation mode”.

[0081] In the embodiment shown in FIG. 1, the enclosure 110 includes a first enclosure portion 128 and a second enclosure portion 130 joined together. More specifically, in the embodiment shown, the first and second enclosure portions 128 and 130 are joined together by a weld to form a welded perimeter joint 132. However, in alternative embodiments, enclosure portions may be joined together by other means, such as, for example, adhesives. The second enclosure portion 130 is secured to a mounting plate 134 by fasteners 136 to mount the stator device 104 for operation beneath the working environment 122. The first and second enclosure portions 128 and 130, and thus the enclosure 110, non- releasably surround the stator 108 and thus isolate the stator 108 from an external environment, shown generally at 138, around the stator device 104. In the embodiment shown, the external environment 138 includes the working environment 122 generally above the stator device 104 and a non-working environment, shown generally at 140, generally below the stator device 104. That is, the stator device 104, and thus the stator 108, is positioned between the working environment 122 and the non-working environment 140 at least when the mover 102 is moving in the working environment 122 in response to external magnetic fields generated by the stator 108. In some embodiments, the stator device 104, along with the mounting plate 134, may isolate the working environment from the non-working environment. Further, in some such embodiments, the stator device 104, along with the mounting plate 134, may seal the working environment from the non-working environment.

[0082] In the embodiment shown, the enclosure 110 non-releasably surrounds the stator 108 from all sides of the stator 108, including from above the stator 108 (where the working environment 122 is) and from below the stator 108 (where the non-working environment 140 is), such that the entire stator is encapsulated. Such an arrangement may be desirable in hygienic environments such as food processing and / or pharmaceuticals. More specifically, in the embodiment shown, the enclosure 110 defines a stator environment, shown generally at 142, which contains the stator. In some embodiments, the stator environment 142 may have a pressure which is different from a pressure in the working environment 122 and / or different from a pressure in the non-working environment 140, or, more generally, different from a pressure in the external environment 138. For example, the pressure in the stator environment 142 may be greater than the pressure in the working environment 122. As a more specific example, the working environment 122 may include a vacuum or a near-vacuum and the stator environment 142 may be at or near atmospheric conditions, such that the pressure in the stator environment 142 is about 1 atmosphere greater than the pressure in the working environment 122. However, alternative embodiments may vary. For example, in some alternative embodiments, an enclosure may non-releasably surround a stator from some but not all sides of the stator. In some embodiments, the enclosure 110 may be fixed to the stator 108. For example, the enclosure 110 may be fixed to the stator 108 by an adhesive, by a viscous fluid, by a mechanical interlock, by a vacuum formed between the enclosure 110 and the stator 108, and / or by welding. In some embodiments, an interface between the enclosure 110 and the stator 108 may contain no gaps or pockets of air near atmospheric pressure, or no such air gaps or pockets greater than 10 milliliters in volume. Such air gaps or pockets may cause damage to the stator device 104 (e.g., delamination) when the working environment 122 includes a vacuum or a near-vacuum.

[0083] In some embodiments, the enclosure 110 may be electrically conductive. In some such embodiments, the enclosure 110 may generally be continuously conductive or may have only minimal discontinuities in conductivity throughout the enclosure 110, such that at least some forms of electromagnetic radiation are prevented or impeded from passing through the enclosure 110 and are thus trapped within the enclosure 110. That is, the enclosure 110 may function as a Faraday cage, containing, for example, at least some forms of electromagnetic radiation generated by operation of the stator 108. As a more specific example, in some embodiments, the enclosure 110 may have no breaks, gaps, or discontinuities in electrical conductivity larger than 1 cm.

[0084] In some embodiments, the enclosure 110 may be made up of or may include stainless steel. In some such embodiments, the stator 108 may be surrounded by the stainless steel of the enclosure 110. More specifically, the stator 108 may be surrounded from all sides by the stainless steel of the enclosure 110.

[0085] Still referring to FIG. 1, the second enclosure portion 130 of the enclosure 110 of the embodiment shown defines an enclosure service opening, shown generally at 144. The enclosure service opening 144 may be used, for example, to pass wires, cables, and / or other conduits through from outside the enclosure 110 to inside the enclosure 110 to connect the stator 108 to one or more devices outside of the enclosure 110 (e.g., a power source or a controller). For example, in the embodiment shown, a conduit 146 from the controller 106 passes through the enclosure service opening 144. In embodiments where the enclosure 110 may function as a Faraday cage, metallic or otherwise conductive elements of the conduit 146 may maintain the continuity of electrical conductivity of the enclosure 110 (i.e., at least partly fill in a discontinuity introduced by the enclosure service opening 144).

[0086] In the embodiment shown, a seal 148 is positioned between the second enclosure portion 130 of the enclosure 110 and the mounting plate 134 in order to seal the second enclosure portion 130 against the mounting plate 134 to prevent movement of material between the working environment 122 and the non-working environment 140 (e.g. via an opening in the mounting plate 134 corresponding to the enclosure service opening 144 of the second enclosure portion 130) and / or between the working environment 122 and the stator environment 142 (e.g., via the enclosure service opening 144). In some embodiments, the seal 148 may be, for example, an O-ring. In some embodiments, other sealing mechanisms may be used, such as, for example, gaskets or curing or vulcanizing sealants.

[0087] The enclosure 110 may be manufactured using various manufacturing methods, such as, for example, stamping or cutting and then folding and welding one or more sheets of material. In some embodiments, the second enclosure portion 130 may be machined for more constrained and reliable tolerances, to allow for a more reliable fit between the first and second enclosure portions 128 and 130. Additionally, in some embodiments, other types of welding / sealing shapes may be used at the interface between the first and second enclosure portions 128 and 130.

[0088] Referring now to FIG. 2, a displacement system according to another embodiment is shown generally at 150 and includes a mover 152, a mover 154, a stator device 156, a stator device 158, and one or more controllers (not shown). The movers 152 and 154 may generally be similar to the mover 102 of the displacement system 100 (i.e., of the embodiment of FIG. 1), and the stator devices 156 and 158 may generally be similar to the stator device 104 of the displacement system 100, and may be controlled by the one or more controllers as described above with respect to the controller 106 of the displacement system 100. In this embodiment, the stator devices 156 and 158 are mounted to a single mounting plate 160 to form an assembly 162. The assembly 162 isolates and seals a working environment 164 of the displacement system 150 from a non-working environment 166 of the displacement system 150. Each of the stator devices 156 and 158 has a width 168 which is less than a pitch 170 between the stator devices 156 and 158, such that there is an inter-stator device gap, shown generally at 172, between the stator devices 156 and 158. Alternative embodiments may include different-sized inter-stator device gaps, and some alternative embodiments may not have an inter-stator device gap.

[0089] Referring now to FIG. 3, a displacement system according to another embodiment is shown generally at 180 and includes a mover 182, a stator device 184, and one or more controllers (not shown). The mover 182 may generally be similar to the mover 102 of the displacement system 100 (i.e., of the embodiment of FIG. 1), and the stator device 184 may generally be similar to the stator device 104 of the displacement system 100, and may be controlled by the one or more controllers as described above with respect to the controller 106 of the displacement system 100. Like the stator device 104 of the displacement system 100, the stator device 184 of the embodiment shown in FIG. 3 includes a stator 186 and an enclosure 188 which may function as a barrier between the stator 186 and at least a working environment of the mover 182, shown generally at 190. Like the enclosure 110 of the stator device 104, the enclosure 188 of the embodiment shown in FIG. 3 includes a first enclosure portion 192 and a second enclosure portion 194 joined together by a weld to form a welded perimeter joint 196. The second enclosure portion 194 is secured to a mounting plate 198 by fasteners 200 to mount the stator device 184 for operation beneath the working environment 190, and is sealed to the mounting plate 198 by a seal 202.

[0090] In the embodiment shown in FIG. 3, a portion 204 of the first enclosure portion 192 overlaps a portion 206 of the second enclosure portion 194, such that the portion 206 of the second enclosure portion 194 is between the stator 186 and the portion 204 of the first enclosure portion 192. In some embodiments, a lower portion of the stator 186 may be narrowed (e.g., cut out) relative to an upper portion of the stator 186 such that both the first enclosure portion 192 and the second enclosure portion 194 can lie flush with the stator wall. In the embodiment shown, the second enclosure portion 194 may be too thin to by itself support mounting, via the fasteners 200, of the stator device 184 onto the mounting plate 198. Thus, as shown in FIG. 3, a portion of the stator 186 within the enclosure 188 may receive a portion of each fastener 200 to provide some additional support for mounting.

[0091] Referring now to FIG. 4, a displacement system according to another embodiment is shown generally at 210 and includes a mover 212, a stator device 214, and one or more controllers (not shown). The mover 212 may generally be similar to the mover 102 of the displacement system 100 (i.e., of the embodiment of FIG. 1). The stator device 214 includes a stator 216 and a coating 218 adhered to the stator 216. The stator 216 may generally be similar to the stator 108 of the displacement system 100, and may be controlled by the one or more controllers as described above with respect to the controller 106 of the displacement system 100. More specifically, the stator 216 includes one or more electrical conductors on a stator motor board. In some embodiments, the stator 216 may also include one or more sensors on the stator motor board 220.

[0092] The coating 218 may function as a barrier between the stator 214, or at least the stator motor board 220, and at least a working environment of the mover 212, shown generally at 222, thus isolating the stator 214 (or stator motor board 220) from at least the working environment 222. In the embodiment shown, the coating 218 surrounds the stator 214 along an upper portion of the stator 214 near the working environment 222. However, in alternative embodiments, the coating 218 may surround the stator 214 from all sides of the stator 214, and may thus isolate the stator from not only the working environment 222 but also from other external environments around the stator 214, such as a non-working environment shown generally at 224. In some embodiments, the coating 218 may seal the stator 214 from the working environment 222.

[0093] The coating 218 may provide resistance to the stator 214, and in particular to the stator motor board 220, from adverse conditions in the working environment 222 such as chemicals, water, and vacuum. The coating 218 may also allow the stator 214 and / or the stator motor board 220 to minimally affect the working environment 222. For example, the coating 218 preventing off gassing from the stator motor board 220 into a vacuum in the working environment 222. In some embodiments, the coating 218 may be airtight, non-porous, nonvolatile, non-ab sorptive, and / or smooth.

[0094] In some embodiments, the coating 218 may include a polymer, a ceramic, and / or carbon. In some embodiments, the coating 218 may include a metal. In some such embodiments, the coating 218 may be applied to the stator 214, for example, by electroplating the coating onto the stator 214. In some embodiments, the coating 218 may be electrically conductive. In some such embodiments, the coating 218 may generally be continuously conductive or may have only minimal discontinuities in conductivity throughout the coating 218, such that at least some forms of electromagnetic radiation cannot pass through the coating 218. As a more specific example, in some embodiments, the coating 218 may have no breaks, gaps, or discontinuities in electrical conductivity larger than 1 cm.

[0095] In some embodiments, the coating 218 may define a coating service opening similar to the enclosure service opening 144 of the embodiment of FIG. 1. That is, the coating 218 may define a coating service opening dimensioned to received therethrough one or more utility service conduits associated with the stator 214.

[0096] Referring now to FIG. 5, a displacement system according to another embodiment is shown generally at 230 and includes a mover 232, a stator device 234, and one or more controllers (not shown). The mover 232 may generally be similar to the mover 102 of the displacement system 100 (i.e., of the embodiment of FIG. 1). The stator device 234 includes a stator 236, a cover 238, and a band 240. The stator 236 may generally be similar to the stator 108 of the displacement system 100, and may be controlled by the one or more controllers as described above with respect to the controller 106 of the displacement system 100. More specifically, the stator 236 includes one or more electrical conductors on a stator motor board 242. In some embodiments, the stator 236 may also include one or more sensors on the stator motor board 242.

[0097] In the embodiment shown, the cover 238 is attached to the stator motor board 242 of the stator 236 by an adhesive layer 244. However, in alternative embodiments, the cover 238 may be attached to the stator motor board 242 by other means, such as vacuum pressure or gravity. In the embodiment shown, the band 240 is used to cover a side portion of the stator 236 below the cover 238. Additionally, in the embodiment shown, the band 240 is joined to the cover 238 by a weld to form a welded perimeter joint 246. The band 240 is also joined to the stator 236 by an interference fit with the stator motor board 242, and a seal 248 (such as an O-ring) forms a seal between the band 240 and the stator 236. However, in alternative embodiments, the band 240 may be joined to the stator 236 by other means, such as pressfitting, brazing or welding. In some alternative embodiments, the ring may be incorporated into the stator 236 rather than a separate component. The embodiment shown in FIG. 5 may be particularly easy to assemble. The non-stator components of the stator device 244, such as the cover 238 and the band 240, are generally simple to manufacture and fit together. Additionally, these non-stator components can fit within the perimeter of the stator 236, which allows more freedom in the pitch distance between adjacent stator devices when using multiple stator devices together.

[0098] Clauses

[0099] This disclosure includes but is not limited to the following clauses, which may be combined with other subject matter in this specification.

[0100] 1. A stator device for a displacement system, the stator device comprising: a stator comprising at least one conductor positioned to generate at least one external magnetic field operable to move at least one mover in at least two degrees of freedom in a working environment of the displacement system; and an enclosure non-releasably surrounding the stator and isolating the stator from an external environment comprising the working environment.

[0101] 2. The stator device of clause 1 wherein the enclosure surrounds the stator from all sides of the stator.

[0102] 3. The stator device of clause 1 or 2 wherein: the enclosure defines a stator environment containing the stator; and a pressure in the stator environment is different from a pressure in the working environment.

[0103] 4. The stator device of clause 3 wherein the pressure in the stator environment is greater than the pressure in the working environment.

[0104] 5. The stator device of clause 4 wherein the pressure in the stator environment is about 1 atmosphere greater than the pressure in the working environment.

[0105] 6. The stator device of any one of clauses 1 to 5 wherein the enclosure comprises a plurality of enclosure portions joined together.

[0106] 7. The stator device of clause 6 wherein the plurality of enclosure portions is joined together by at least one weld.

[0107] 8. The stator device of clause 6 or 7 wherein: the plurality of enclosure portions comprises a first enclosure portion and a second enclosure portion; and a portion of the second enclosure portion is between the stator and a portion of the first enclosure portion.

[0108] 9. The stator device of any one of clauses 1 to 8 wherein the enclosure is fixed to the stator.

[0109] 10. The stator device of clause 9 wherein the enclosure is fixed to the stator by an adhesive.

[0110] 11. The stator device of clause 9 or 10 wherein the enclosure is fixed to the stator by a viscous fluid.

[0111] 12. The stator device of clause 9, 10, or 11 wherein the enclosure is fixed to the stator by a mechanical interlock.

[0112] 13. The stator device of any one of clauses 9 to 12 wherein the enclosure is fixed to the stator by a vacuum formed between the enclosure and the stator.

[0113] 14. The stator device of any one of clauses 9 to 13 wherein the enclosure is fixed to the stator by a weld.

[0114] 15. The stator device of any one of clauses 1 to 14 wherein the enclosure is electrically conductive.

[0115] 16. The stator device of clause 15 wherein the enclosure has no discontinuity in electrical conductivity larger than 1 cm.

[0116] 17. The stator device of any one of clauses 1 to 16 wherein the enclosure defines an enclosure service opening dimensioned to received therethrough one or more utility service conduits associated with the stator.

[0117] 18. The stator device of any one of clauses 1 to 17 wherein the enclosure comprises stainless steel.

[0118] 19. The stator device of clause 18 wherein the stator is surrounded by the stainless steel of the enclosure.

[0119] 20. The stator device of any one of clauses 1 to 19 wherein the enclosure comprises a coating adhered to the stator.

[0120] 21. A stator device for a displacement system, the stator device comprising: a stator comprising at least one conductor positioned to generate at least one external magnetic field operable to move at least one mover in a working environment of the displacement system; and a coating adhered to the stator, the coating isolating the stator from an external environment comprising the working environment.

[0121] 22. The stator device of clause 21 wherein the at least one external magnetic field is operable to move the at least one mover in at least two degrees of freedom in the working environment.

[0122] 23. The stator device of clause 20, 21, or 22 wherein the coating surrounds the stator.

[0123] 24. The stator device of clause 23 wherein the coating surrounds the stator from all sides of the stator.

[0124] 25. The stator device of any one of clauses 20 to 24 wherein the coating seals the stator from the working environment.

[0125] 26. The stator device of any one of clauses 20 to 25 wherein the coating is airtight.

[0126] 27. The stator device of any one of clauses 20 to 26 wherein the coating is electrically conductive.

[0127] 28. The stator device of clause 27 wherein the coating has no discontinuity in electrical conductivity larger than 1 cm.

[0128] 29. The stator device of any one of clauses 20 to 28 wherein the coating is non- porous.

[0129] 30. The stator device of any one of clauses 20 to 29 wherein the coating is nonvolatile.

[0130] 31. The stator device of any one of clauses 20 to 30 wherein the coating is non- absorptive.

[0131] 32. The stator device of any one of clauses 20 to 31 wherein the coating is smooth.

[0132] 33. The stator device of any one of clauses 20 to 32 wherein the coating defines a coating service opening dimensioned to received therethrough one or more utility service conduits associated with the stator. 34. The stator device of any one of clauses 20 to 33 wherein the coating comprises a polymer coating.

[0133] 35. The stator device of any one of clauses 20 to 34 wherein the coating comprises a ceramic.

[0134] 36. The stator device of any one of clauses 20 to 35 wherein the coating comprises a metal.

[0135] 37. The stator device of any one of clauses 20 to 36 wherein the coating comprises carbon.

[0136] 38. The stator device of any one of clauses 1 to 37 wherein the external environment further comprises a non-working environment, the stator between the working environment and the non-working environment at least when the at least one mover is moving in the working environment in response to the at least one external magnetic field.

[0137] 39. The stator device of clause 38 wherein the stator device isolates the working environment from the non-working environment.

[0138] 40. The stator device of clause 39 wherein the stator device seals the working environment from the non-working environment.

[0139] 41. The stator device of any one of clauses 1 to 39 wherein the stator further comprises at least one sensor positioned to measure at least a magnetic field from at least one magnet of the at least one mover when the at least one mover is positioned within a sensor range of the at least one sensor.

[0140] 42. The stator device of any one of clauses 1 to 41 wherein the stator further comprises a driving circuit operable to drive at least one electrical current in the at least one conductor to cause the at least one conductor to generate the at least one external magnetic field.

[0141] 43. The stator device of clause 42 when directly or indirectly dependent from clause 41 further comprising a controller configured to control the driving circuit to drive the at least one electrical current in the at least one conductor in response to at least the magnetic field measured by the at least one sensor. Although specific embodiments have been described and illustrated, such embodiments should be considered illustrative only and not as limiting the invention as construed according to the accompanying claims.

Claims

CLAIMS1. A stator device for a displacement system, the stator device comprising: a stator comprising at least one conductor positioned to generate at least one external magnetic field operable to move at least one mover in at least two degrees of freedom in a working environment of the displacement system; and an enclosure non-releasably surrounding the stator and isolating the stator from an external environment comprising the working environment.

2. The stator device of claim 1 wherein the enclosure surrounds the stator from all sides of the stator.

3. The stator device of claim 1 or 2 wherein: the enclosure defines a stator environment containing the stator; and a pressure in the stator environment is different from a pressure in the working environment.

4. The stator device of claim 3 wherein the pressure in the stator environment is greater than the pressure in the working environment.

5. The stator device of claim 4 wherein the pressure in the stator environment is about 1 atmosphere greater than the pressure in the working environment.

6. The stator device of any one of claims 1 to 5 wherein the enclosure comprises a plurality of enclosure portions joined together.

7. The stator device of claim 6 wherein the plurality of enclosure portions is joined together by at least one weld.

8. The stator device of claim 6 or 7 wherein: the plurality of enclosure portions comprises a first enclosure portion and a second enclosure portion; anda portion of the second enclosure portion is between the stator and a portion of the first enclosure portion.

9. The stator device of any one of claims 1 to 8 wherein the enclosure is fixed to the stator.

10. The stator device of claim 9 wherein the enclosure is fixed to the stator by an adhesive.

11. The stator device of claim 9 or 10 wherein the enclosure is fixed to the stator by a viscous fluid.

12. The stator device of claim 9, 10, or 11 wherein the enclosure is fixed to the stator by a mechanical interlock.

13. The stator device of any one of claims 9 to 12 wherein the enclosure is fixed to the stator by a vacuum formed between the enclosure and the stator.

14. The stator device of any one of claims 9 to 13 wherein the enclosure is fixed to the stator by a weld.

15. The stator device of any one of claims 1 to 14 wherein the enclosure is electrically conductive.

16. The stator device of claim 15 wherein the enclosure has no discontinuity in electrical conductivity larger than 1 cm.

17. The stator device of any one of claims 1 to 16 wherein the enclosure defines an enclosure service opening dimensioned to received therethrough one or more utility service conduits associated with the stator.

18. The stator device of any one of claims 1 to 17 wherein the enclosure comprises stainless steel.

19. The stator device of claim 18 wherein the stator is surrounded by the stainless steel of the enclosure.

20. The stator device of any one of claims 1 to 19 wherein the enclosure comprises a coating adhered to the stator.

21. A stator device for a displacement system, the stator device comprising: a stator comprising at least one conductor positioned to generate at least one external magnetic field operable to move at least one mover in a working environment of the displacement system; and a coating adhered to the stator, the coating isolating the stator from an external environment comprising the working environment.

22. The stator device of claim 21 wherein the at least one external magnetic field is operable to move the at least one mover in at least two degrees of freedom in the working environment.

23. The stator device of claim 20, 21, or 22 wherein the coating surrounds the stator.

24. The stator device of claim 23 wherein the coating surrounds the stator from all sides of the stator.

25. The stator device of any one of claims 20 to 24 wherein the coating seals the stator from the working environment.

26. The stator device of any one of claims 20 to 25 wherein the coating is airtight.

27. The stator device of any one of claims 20 to 26 wherein the coating is electrically conductive.

28. The stator device of claim 27 wherein the coating has no discontinuity in electrical conductivity larger than 1 cm.

29. The stator device of any one of claims 20 to 28 wherein the coating is non-porous.

30. The stator device of any one of claims 20 to 29 wherein the coating is non-volatile.

31. The stator device of any one of claims 20 to 30 wherein the coating is non-absorptive.

32. The stator device of any one of claims 20 to 31 wherein the coating is smooth.

33. The stator device of any one of claims 20 to 32 wherein the coating defines a coating service opening dimensioned to received therethrough one or more utility service conduits associated with the stator.

34. The stator device of any one of claims 20 to 33 wherein the coating comprises a polymer coating.

35. The stator device of any one of claims 20 to 34 wherein the coating comprises a ceramic.

36. The stator device of any one of claims 20 to 35 wherein the coating comprises a metal.

37. The stator device of any one of claims 20 to 36 wherein the coating comprises carbon.

38. The stator device of any one of claims 1 to 37 wherein the external environment further comprises a non-working environment, the stator between the working environment and the non-working environment at least when the at least one mover is moving in the working environment in response to the at least one external magnetic field.

39. The stator device of claim 38 wherein the stator device isolates the working environment from the non-working environment.

40. The stator device of claim 39 wherein the stator device seals the working environment from the non-working environment.

41. The stator device of any one of claims 1 to 39 wherein the stator further comprises at least one sensor positioned to measure at least a magnetic field from at least one magnet of the at least one mover when the at least one mover is positioned within a sensor range of the at least one sensor.

42. The stator device of any one of claims 1 to 41 wherein the stator further comprises a driving circuit operable to drive at least one electrical current in the at least one conductor to cause the at least one conductor to generate the at least one external magnetic field.

43. The stator device of claim 42 when directly or indirectly dependent from claim 41 further comprising a controller configured to control the driving circuit to drive the at least one electrical current in the at least one conductor in response to at least the magnetic field measured by the at least one sensor.