Displacement system and mover and stator device therefor

Abstract

Aspects of the present disclosure provide a mover operable to move in response to external magnetic fields. The mover may include magnets for generating forces for moving the mover in response to the magnetic fields, and a support surface. The support surface may be rotatable relative to the magnets. The mover may be positionable to contact, with at least the support surface, a working surface of a stator device operable to generate the magnetic fields. Aspects of the present disclosure also provide a stator device for a displacement system. The stator device may include a stator for generating magnetic fields operable to move movers of the displacement system, a working surface between the movers and the stator during operation, and a support surface. The support surface may support the movers and may be rotatable relative to the working surface around a support rotation axis non-parallel to the working surface.

Description

[0001] DISPLACEMENT SYSTEM AND MOVERAND STATOR DEVICE THEREFOR

[0002] CROSS-REFERENCE TO RELATED APPLICATION

[0003] This application claims the benefit of and priority from United States provisional patent application no. 63 / 631,917, filed April 9, 2024, the entire contents of which are incorporated by reference herein.

[0004] FIELD

[0005] This disclosure relates generally to displacement systems or conveyors and movers 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 CONTROLL ABLY 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, existing systems may be better suited to translation of a mover than they are to rotation of that mover about a vertical axis, and may have limited mover carrying capacity during such mover rotation.

[0011] SUMMARY

[0012] Embodiments of the present disclosure may provide displacement systems having increased mover carrying capacity for mover rotation relative to a working surface, and movers and stator devices for such displacement systems.

[0013] According to at least one embodiment, there is disclosed mover operable to move in response to at least one external magnetic field, the mover comprising: at least one actuation magnet, the at least one actuation magnet configured to generate forces for moving the mover in response to the at least one external magnetic field; and at least one support body comprising at least one support surface, the at least one support surface rotatable relative to the at least one actuation magnet, wherein the mover is positionable to contact, with at least the at least one support surface, a working surface of a stator device operable to generate the at least one external magnetic field. According to at least another embodiment, there is disclosed a stator device for a displacement system, the stator device comprising: at least one stator comprising at least one conductor positioned to generate at least one external magnetic field operable to move at least one mover of the displacement system; a working surface configured to be between the at least one mover and one or more of the at least one stator when the at least one mover is moving in response to the at least one external magnetic field; and at least one support body attached to the working surface, the at least one support body comprising at least one support surface, the at least one support surface rotatable relative to the working surface around a support rotation axis non-parallel to the working surface, the at least one support surface operable to support the at least one mover.

[0014] According to at least another embodiment, there is disclosed a displacement system comprising: the mover as described above; and the stator device as described above.

[0015] According to at least another embodiment, there is disclosed a method of operating the displacement system as described above, the method comprising causing the at least one stator to cause the mover to contact the working surface with the at least one support surface of the mover.

[0016] According to at least another embodiment, there is disclosed a method of operating the displacement system as described above, the method comprising causing the at least one stator to cause the mover to contact the at least one support surface of the stator device.

[0017] 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.

[0018] BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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.

[0020] FIG. l is a front sectional view of a displacement system according to one embodiment. FIG. 2 is a front sectional view of the displacement system of FIG. 1, with a mover of the displacement system landed on a working surface of the displacement system.

[0021] FIG. 3 is a front sectional view of a displacement system according to another embodiment.

[0022] FIG. 4 is a top sectional view of the displacement system of FIG. 3, taken along the line labelled FIG. 4 in FIG. 3.

[0023] FIG. 5 is a front sectional view of a displacement system according to another embodiment.

[0024] FIG. 6 is a front sectional view of a displacement system according to another embodiment.

[0025] FIG. 7 is a front view of a displacement system according to another embodiment.

[0026] FIG. 8 is a top sectional view of the displacement system of FIG. 7, taken along the line labelled FIG. 8 in FIG. 7.

[0027] FIG. 9 is a front sectional view of a displacement system according to another embodiment.

[0028] FIG. 10 is a front sectional view of the displacement system of FIG.9, with a mover of the displacement system landed on a working surface of the displacement system.

[0029] FIG. 11 is a front sectional view of a displacement system according to another embodiment.

[0030] FIG. 12 is a front sectional view of the displacement system of FIG. 11, with a mover of the displacement system landed on a support surface of a stator device of the displacement system.

[0031] DETAILED DESCRIPTION

[0032] 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, utility conduits, and / or protective covers. Described herein are movers and stator devices which include rotatable supports for supporting rotation of a mover relative to its actuating stator, along with displacement systems incorporating such movers and stator devices.

[0033] Referring to FIGS. 1 and 2, 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.

[0034] The stator device 104 includes a 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 the displacement system 100. In the embodiment shown, the stator device 104 includes only the one stator 108. However, alternative embodiments may include stator devices incorporating multiple stators, and in some alternative embodiments, the multiple stators may be of different types - for example, in some alternative embodiments, some stators may have large work areas, while other stators 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.

[0035] 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 device 104 or the stator 108. In embodiments where the controller 106 is completely integrated within the stator 108, 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.

[0036] 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.

[0037] 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).

[0038] The mover 102 includes a structural frame 110, one or more actuation magnets 112 fixed to the structural frame 110, and a support body 114 also fixed to the structural frame 110. The structural frame 110 may provide support to and between the magnets 112 and the support body 114, may facilitate bonding, and / or may provide an interface for a part, fixture, or tooling. In some embodiments, the structural frame 110 may optionally be used to mount additional mounting or locating features (not shown).

[0039] The one or more actuation magnets 112 may also be referred to as an “actuation magnet assembly” or, more generally, a “magnet assembly”. The one or more actuation magnets 112 may be, for example, permanent magnets. In some embodiments, the one or more actuation magnet 112 may include a plurality of magnetization regions, each magnetization region having a respective magnetization direction. In FIGS. 1 and 2, the mover 102 is shown as including at least two actuation magnets 112. However, in some embodiments, the mover 102 may include only one actuation magnet 112, while in other embodiments, the mover 102 may include more than two actuation magnets 112. Generally, one, some, or all of the actuation magnets 112 of the mover 102 may be fixed to the structural frame 110. The actuation magnets 112 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).

[0040] The support body 114 includes a support surface 116 which is rotatable, relative to the structural frame 110 and thus the actuation magnets 112, around a support rotation axis 118. More specifically, in the embodiment shown, the support surface 116 is rotatable, relative to the structural frame 110 and the actuation magnets 112, a full 360° around the support rotation axis 118. Apart from such rotation around the support rotation axis 118, the support body 114 of the embodiment shown generally restricts movement of the support surface 116 relative to the support body 114, such that the support rotation axis 118 of the support surface 116 is fixed (i.e., in a fixed position) relative to the support body 114. As described above, both the actuation magnets 112 and the support body 114 are fixed to the structural frame 110. Therefore, in the embodiment shown, the support rotation axis 118 is fixed relative to the actuation magnets 112, and thus each of the actuation magnets 112 is fixed relative to the support rotation axis 118.

[0041] Generally, the support body 114 is configured to support the mover 102 when the mover 102 contacts an extraneous surface with, at least, the support surface 116 of the support body 114. For example, if the mover 102 vertically “lands” on a horizontal extraneous surface with the support surface 116, then the support body 114 may support some or all of a weight of the mover 102 on that extraneous surface. Because the support surface 116 is rotatable relative to the structural frame 110 and the actuation magnets 112, when the mover 102 lands on the extraneous surface, the support body 114 may support the structural frame 110 and the actuation magnets 112 for rotation relative to the extraneous surface. In the embodiment shown, the support body 114 includes a ball bearing including an inner race 120, an outer race 122, and a plurality of bearing balls 124. The support surface 116 is attached to the inner race 120, the outer race 122 is fixed to the structural frame 110, and the bearing balls 124 support rotation of the inner race 120 relative to the outer race 122, such that the support surface 116 is rotatable relative to the structural frame 110 (and thus the actuation magnets 112 attached thereto).

[0042] Of course, the support body 114 of the embodiment shown in FIGS. 1 and 2 is an example only, and alternative embodiments may differ. For example, in some alternative embodiments, the support surface 116 may instead be attached to the outer race 122, and the inner race 120 may instead be fixed to the structural frame 110. In the embodiment shown in FIGS. 1 and 2, the support rotation axis 118 (around which the support surface 116 is rotatable relative to the structural frame 110 and the actuation magnets 112) is non-parallel to the support surface 116. More specifically, the support rotation axis 118 is transverse to the support surface 116. Even more specifically, in the embodiment shown, the support rotation axis 118 is perpendicular to the support surface 116. However, alternative embodiments may include a support body having a support surface which is rotatable around a support rotation axis parallel to the support surface (see, e.g., FIGS. 7 and 8 below). Also in the embodiment shown in FIGS. 1 and 2, the support surface 116 is planar. However, alternative embodiments may include a support surface which is non-planar. For example, in some such alternative embodiments, the support surface may be curved and / or convex (again, see, e.g., FIGS. 7 and 8 below). A curved and / or convex support surface may allow, on contact between the support surface and a surface extraneous to the mover, a small amount of rotation relative to the extraneous surface around an axis non-parallel to the support rotation axis. Such additional rotation may be desirable for mover levelling purposes. Additionally, although the support body 114 of the embodiment shown includes a ball bearing, in alternative embodiments the support body may include more than one ball bearing and / or may include one or more other types of rolling element bearings. More generally, in embodiments such as the embodiment shown in FIGS. 1 and 2, a support body of the mover may include one or more rolling or rotating parts such as bearings (including mechanical bearings, sliding bearings, air bearings, and / or magnetic bearings) and / or wheels which allow a support surface of the support body to rotate, relative to at least actuation magnets of the mover, around a support rotation axis.

[0043] Still referring to FIGS. 1 and 2, the stator 108 includes sensors 126, electrical conductors 128, and an amplifier 130. Each of the sensors 126 is configured to measure at least one magnetic field. Each of the sensors 126 may only accurately measure a magnetic field within a certain range of that sensor 126. Examples of such sensors are described and illustrated in United States patent no. US 10,222,237 as magnetic field sensors 501. The sensors 126 may include, for example, Hall-effect 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 126; however, it will be appreciated that in some alternative embodiments, the stator 108 may include a different number of sensors 126, or may not include any sensors. These sensors 126 may also be arranged at positions extending along the Y direction in addition to different X positions that are shown in FIG. 1.

[0044] Each of the electrical conductors 128 is configured to generate at least one external magnetic field. The electrical conductors 128 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 128; however, it will be appreciated that in some alternative embodiments, the stator 108 may include only one electrical conductor 128, two electrical conductors 128, three electrical conductors 128, or more than four electrical conductors 128. 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 128 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 include a second coil pitch or spacing in a second direction (e.g., the Y-direction as shown in FIG. 1). The electrical conductors 128 may also include a second group of coils that are linearly elongated in the second direction. The second group of coils may 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 128 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.

[0045] The sensors 126 and electrical conductors 128 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 126 configured around each of the electrical conductors 128, such as one of the sensors 126 at each edge of one of the electrical conductors 128. Other patterns may also be possible. It will be appreciated that the sensors 126 may be arranged in patterns near or around the electrical conductors 128 to provide proper feedback to the controller 106 for position sensing and control of the mover 102, for example. The amplifier 130 is connected to the electrical conductors 128. In some embodiments, the amplifier 130 may be referred to as a “driving circuit” or a “stator driving circuit”. In general, the amplifier 130 may drive one or more electrical currents in the electrical conductors 128, generating one or more external magnetic fields. The controller 106 may be connected to deliver control signals to the amplifier 130. The control signals may be used to control current driven by the amplifier 130 into the electrical conductors 128. In the embodiment shown in FIG. 1, the stator 108 includes one amplifier 130. However, in alternative embodiments, a stator may include more than one amplifier.

[0046] The current controllably driven into each of the electrical conductors 128 may cause that electrical conductor 128 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 actuation magnets 112, thereby moving the mover 102 relative to the stator 108. 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.

[0047] In the embodiment shown, the stator device 104 includes a cover 132 overlaying the stator 108. The cover 132 may overlay an entire top surface of the stator 108 and may function as a barrier between the stator 108 and an operating environment of the mover 102, shown generally at 134. The operating environment 134 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 cover 132 may protect the stator 108 from adverse conditions in the operating environment 134, such as humidity, liquids, and / or corrosive environments. In some embodiments, the cover 132 may protect the operating environment 134 from contamination. The cover 132 may be made up of one or more materials that minimally interact with magnetic fields, such as non-magnetic steel (i.e., austenitic stainless steel), plastic, ceramic, aluminum, titanium, or other minimally magnetic or non-magnetic materials. In some embodiments, the cover 132 may be subject to internal stresses (e.g., tensile stresses) when installed.

[0048] The cover 132 includes and thus supports a working surface 136 for the mover 102 to move upon. Generally, the working surface 136 describes a continuous area of the cover 132 upon which the mover 102 may be controlled by the stator 108. That is, when the cover 132 overlays the stator 108, the working surface 136 is between the stator 108 and the operating environment 134, and is thus between the stator 108 and the mover 102 when the mover 102 is being controlled by the stator 108 (i.e., when the mover 102 is moving in response to external magnetic fields generated by the stator 108). Suitable feedback control algorithms executed by the controller 106 and suitable position feedback from the sensors 126 allow the controller 106 and the stator 108 to control the mover 102 along the working surface 136. The working surface 136 may be flat, curved, cylindrical, spherical or some other shape that allows the mover 102 to move along the working surface 136. In some embodiments, a combined working surface may be defined by a plurality of stators each having a respective stator cover, such that each working surface of each stator cover may be combined into a larger combined working surface. In other embodiments, a single stator cover or unitary cover may overlay a plurality of stators, forming a single continuous working surface. While the working surface 136 is depicted horizontally in FIG. 1, it should be understood that the working surface 136 may be mounted vertically or at an angle to gravity.

[0049] In general, under the control of the controller 106, the mover 102 may move (e.g., translation and / or rotation) along or over the working surface 136 in a “contact mode”, wherein at least a part of the mover 102 contacts the working surface 136, as depicted in FIG. 2, or a “non-contact mode”, wherein no part of the mover 102 contacts the working surface 136, as depicted in FIG. 1. The contact mode (also known as “sitting mode”) may involve separate contact media such as sliding and / or rolling bearings between the mover 102 and the working surface 136. The non-contact mode (also known as “levitation mode”) may require maintaining a controllable gap 138 between all parts of the mover 102 and the working surface 136 of the cover 132 in a normal direction Z. The gap 138 may be an air gap. The mover 102 may also rest upon or over the working surface 136 without moving, which may be in a contact mode or a non-contact mode. In the non-contact mode, the mover 102 may have 6- DOF controllable motion (known as “active levitation mode”). Alternatively, the mover 102 may maintain the gap 138 by passive levitation means (known as “passive levitation mode”). In the passive levitation mode, the mover 102 may rest above the working surface 136 in the non-contact mode.

[0050] In some embodiments, the magnetic forces associated with the interactions between the magnetic fields created by the currents in the electrical conductors 128 and the magnetic fields associated with the actuation magnets 112 may attract the mover 102 toward the stator 108, and thus the working surface 136, at all times when the controller 106 is controlling the currents driven by the amplifier 130. In other embodiments, the magnetic forces associated with the interactions between the magnetic fields created by the currents in the electrical conductors 128 and the magnetic fields associated with the actuation magnet 112 may force the mover 102 away from the stator 108, and thus the working surface 136, in order to balance gravitational forces to maintain the gap 138 at all times.

[0051] In some embodiments, the gap 138 between the mover 102 and the working surface 136 of the cover 132 may be maintained by air bearings or compressed-fluid bearings. It will be appreciated that in some embodiments, the gap 138 may be zero, such as when the mover 102 operates in contact mode.

[0052] As described above, the mover 102 may work in “levitation mode”, being levitated near the working surface 136 of the cover 132 without contacting the cover 132. In the levitation mode, the mover 102 can perform translation and rotation motions about all axes. For example, the mover 102 may move along the working surface 136 in X and Y directions, where X and Y are two non-parallel (e.g., orthogonal) directions inside the working surface 136. It will be appreciated that the gap 138 between the working surface 136 and a bottommost surface of the mover 102 (e.g., the support surface 116 in FIG. 1) may generally be much smaller than the mover’s lateral dimensions (i.e., dimensions in the X and Y directions).

[0053] 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 at all times and heavy load carrying capability of the mover 102 may be desirable. In such embodiments, for at least some types of movement, the mover 102 may be controlled by the stator 108 to land and sit on the working surface 136 with, for example, the support surface 116. In particular, when carrying a heavy payload, the mover 102 may be controlled by the stator to land, with the support surface 116, on the working surface 136 for rotation of the payload around a Z direction normal to the working surface 136. Such rotation may be supported by the support body 114. Landing during such rotation may improve rotation precision, may allow the application of a large force during rotation to a component carried by the mover 102, may improve efficiency of rotation motion, and / or may increase allowable mover payload.

[0054] Still referring to FIGS. 1 and 2, the mover 102 includes an external surface 140 which includes the support surface 116 of the support body 104 as well as a stator-facing surface 142 which is positioned to face the working surface 136 at least when the support surface 116 contacts the working surface 136. In the embodiment shown, the stator-facing surface 142 is adjacent to and positioned around the support surface 116. A portion of the support body 104 which includes the support surface 116 protrudes a protrusion distance 144 from the statorfacing surface 142, such that when the mover 102 is oriented with the support surface 116 and the stator-facing surface 142 facing the working surface 136 of the stator device 104, the support surface 116 is closer to the working surface 136 than the stator-facing surface 142. For example, when the mover 102 is levitating away from the working surface 136 in non- contact / levitation mode, as depicted in FIG. 1, the support surface 116 is separated from the working surface 136 by the gap 138, while the stator-facing surface 142 is separated from the working surface 136 by a larger gap 146. Similarly, when the mover 102 is in contact / sitting mode with the support surface 116 in contact with the working surface 136, the stator-facing surface 142 remains separated from the working surface 136 by the protrusion distance 144.

[0055] In general, the mover 102 is positionable to contact the working surface 136 with at least the support surface 116. As shown in FIG. 2, the mover 102 may be positioned to contact the working surface 136 with only the support surface 116. Thus, in general, the support surface 116 is accessible from an exterior of the mover 102 (e.g., from the operating environment 134).

[0056] In general, the support body 104 is configured to support the mover 102 on the working surface when the support surface 116 is in contact with the working surface 136. More specifically, when the support surface 116 is in contact with the working surface 136, the support body 104 is configured to support the mover 102 against one or more forces - e.g., due to gravity - urging the mover 102 toward the working surface 136. For example, the support body 104 may support at least some of, a majority of, or all of a weight of the mover 102 on the working surface 136 when the support surface 116 contacts the working surface 136. When the mover 102 is carrying a payload, the support body 104 may also support a majority of or all of a combined weight of the mover 102 and the carried payload when the support surface 116 contacts the working surface 136. In some embodiments, such a payload may have a weight of, for example, at least 75% of the weight of the mover 102.

[0057] As described above, the support surface 116 is rotatable, relative to the structural frame 110 and the actuation magnets 112, around the support rotation axis 118. Thus, when the support surface 116 is in contact with the working surface 136, the support body 104 may support the mover 102 - including the structural frame 110 and the actuation magnets 112 — for rotation relative to the working surface 136 around a mover rotation axis 148. When the support body 104 thus supports the mover 102 for rotation on the working surface 136, the support surface 116 may remain rotationally stationary relative to the working surface 136. Thus, such supported rotation of the mover 102 around the mover rotation axis 148 may in turn cause rotation of the support surface 116, relative to the structural frame 110 and the actuation magnets 112, around the support rotation axis 118. Non-rotation of the support surface 116 relative to the working surface 136 when the when the support surface 116 contacts the working surface 136 may reduce damage or wear on the working surface 136 when the support body 104 supports the mover 102 on the working surface 136 for rotation around the mover rotation axis 148, especially when the mover 102 is carrying a heavy payload.

[0058] In general, when the mover 102 contacts the working surface 136 with the support surface 116 and is supported by the support body 104 for rotation relative to the working surface around the mover rotation axis 148, the mover may be subject to a first resistance to rotation (e.g., due to friction) around the mover rotation axis 148. Conversely, when the mover 102 contacts the working surface 136 with any other portion or portions of its external surface, such as with the stator-facing surface 142, the mover may be subject to a second resistance to rotation (e.g., due to friction) around the mover rotation axis 148, which may be greater than the first resistance to rotation. That is, the support body 114 (including the rotatable support surface 116) may generally reduce resistance to rotation around at least the mover rotation axis 148 when the mover 102 contacts the working surface 136.

[0059] In the embodiment shown in FIGS. 1 and 2, the mover rotation axis 148 is non-parallel to the working surface 136. More specifically, in the embodiment shown, the mover rotation axis 148 is transverse to the working surface 136. Even more specifically, in the embodiment shown, the mover rotation axis 148 is perpendicular to the working surface 136. Also in the embodiment shown in FIGS. 1 and 2, the mover rotation axis 148 is colinear with the support rotation axis 118. However, in alternative embodiments, the mover rotation axis may be non- colinear with the support rotation axis.

[0060] As described above, in operation, the controller 106 may control the stator 108 to generate at least one external magnetic field operable to move the mover 102. For example, the controller 106 may control the stator 108 to generate at least one external magnetic field to cause the mover 102 to levitate above the working surface 136 (i.e., in non-contact / levitation mode), including above any protrusion from the working surface 136 (see, e.g., FIGS. 9 to 12). That is, the mover 102 may be moved over the working surface 136 at a levitation distance away from the working surface which is greater than a length of any protrusion from the working surface. The controller 106 may also control the stator 108 to generate at least one external magnetic field to cause the mover 102 to contact the working surface 136 with the support surface 116 (i.e., to “land” on the working surface 136). That is, the mover 102 may be positionable to contact the working surface 136 with or via the support surface 116 in response to the at least one external magnetic field generated by the stator 108. When the the support surface 116 is in contact with the working surface 136 such that the support body 104 supports the mover 102 on the working surface 136, the controller 106 may also control the stator 108 to generate at least one external magnetic field to cause the mover 102 to rotate at least the actuation magnets 112 relative to the working surface 136 around the mover rotation axis 148. Thus, for example, the mover 102 may be controlled to carry a payload while levitating over the working surface 136, land on the working surface 136 with the support surface 116, rotate the payload relative to the working surface 136, and then levitate up away from the working surface 136. Such operation may provide the mover 102 with an increased carrying capacity for rotation relative to the working surface 136.

[0061] In some embodiments, when the mover 102 is vertically above the working surface 136 with the support surface 116 in contact with the working surface 136 and the support body 104 supporting the mover 102, a center of mass or center of gravity of the mover 102, or of the mover 102 and a carried payload, may not vertically overlap (i.e., may not be above) an interface between the support surface 116 and the working surface 136, or may vertically overlap (i.e., may be above) a periphery of this interface, or - more generally - may be further away from the mover rotation axis 148 than any portion of this interface. In such embodiments, the support body 104 may experience a moment resulting from the weight of the mover or mover and payload, and may be configured to support the mover 102 against such a moment. Further, in such embodiments, the controller 106 may be configured to control the stator 108 to maintain an orientation of the mover 102 relative to the working surface 136, as variations in the orientation of the mover 102 may cause the mover 102 to come into further contact with (and potentially get caught on) the working surface 136 and / or other parts of the stator device 104.

[0062] Of course, the support body 114 of the embodiment shown in FIGS. 1 and 2 is an example only, and alternative embodiments may differ. For example, some alternative embodiments may include a mover with more than one support body (i.e., a plurality of support bodies), and thus more than one support surface (i.e., a plurality of support surfaces). In such embodiments, each of the support bodies may include one or more of the support surfaces (see, e.g., FIGS. 7 and 8 below). Also, in some alternative embodiments, the support surface of the support body may be above a top surface of the mover.

[0063] Referring now to FIGS. 3 and 4, a displacement system according to another embodiment is shown generally at 150 and includes a mover 152, a stator device 154, and a controller (not shown). The stator device 154 may generally be similar to the stator device 104 of the displacement system 100 (i.e., of the embodiment of FIGS. 1 and 2), and includes one or more stators (not shown) and a working surface 156. The mover 152 is generally similar to the mover 102 of the of the displacement system 100 (i.e., of the embodiment of FIGS. 1 and 2), and includes a structural frame 158 similar to the structural frame 110 of the mover 102, actuation magnets 160 fixed to the structural frame 158 which may be similar to the actuation magnets 112 of the mover 102, and a support body 162 also fixed to the structural frame 158. Similar to the support body 114 of the mover 102, the support body 162 includes a support surface 164 which is rotatable, relative to the structural frame 158 and the actuation magnets 160, around a support rotation axis 166. When the mover 152 contacts the working surface 156 with the support surface 164, the support body 162 is generally configured to support the mover 152 for rotation, relative to the working surface 156, around a mover rotation axis 168 colinear with the support rotation axis 166. However, unlike the support body 114 of the mover 102, the support body 162 is a radial ball bearing which surrounds at least the actuation magnets 160 in at least one plane passing through the mover 152 (for example, as depicted in FIG. 3, a plane parallel to the working surface 156), such that the support surface 164 is at a periphery of the mover 152. The support body 162 includes an outer race 170 which includes the support surface 164 and a plurality of bearing balls 172 which support rotation of the structural frame 158 (acting as an inner race) relative to the outer race 170 around the support rotation axis 166.

[0064] Referring now to FIG. 5, a displacement system according to another embodiment is shown generally at 180 and includes a mover 182, a stator device 184, and a controller (not shown). The stator device 184 may generally be similar to the stator device 104 of the displacement system 100 (i.e., of the embodiment of FIGS. 1 and 2), and includes one or more stators (not shown) and a working surface 186. The mover 182 is generally similar to the mover 102 of the of the displacement system 100 (i.e., of the embodiment of FIGS. 1 and 2), and includes a structural frame 188 similar to the structural frame 110 of the mover 102, actuation magnets 190 fixed to the structural frame 188 which may be similar to the actuation magnets 112 of the mover 102, and a support body 192 also fixed to the structural frame 188. Similar to the support body 114 of the mover 102, the support body 192 includes a support surface 194 which is rotatable, relative to the structural frame 188 and the actuation magnets 190, around a support rotation axis 196. When the mover 182 contacts the working surface 186 with the support surface 194, the support body 192 is generally configured to support the mover 182 for rotation, relative to the working surface 186, around a mover rotation axis 198 colinear with the support rotation axis 196. However, unlike the support body 114 of the mover 102, the support body 192 is an axial ball bearing or thrust bearing. The support body 192 includes a lower race 200 which includes the support surface 194, an upper race 202 which is fixed to the structural frame 188, and a plurality of bearing balls 204 which support rotation of the lower race 200 relative to the upper race 202 around the support rotation axis 196. During operation, and in particular when the mover 182 is in non-contact / levitating mode, mechanical or magnetic retaining means may be used to keep the support body (i.e., the lower race 200, upper race 202, and bearing balls 204) together.

[0065] Referring now to FIG. 6, a displacement system according to another embodiment is shown generally at 210 and includes a mover 212, a stator device 214, and a controller (not shown). The stator device 214 may generally be similar to the stator device 104 of the displacement system 100 (i.e., of the embodiment of FIGS. 1 and 2), and includes one or more stators (not shown) and a working surface 216. The mover 212 is generally similar to the mover 102 of the of the displacement system 100 (i.e., of the embodiment of FIGS. 1 and 2), and includes a structural frame 218 similar to the structural frame 110 of the mover 102, actuation magnets 220 fixed to the structural frame 218 which may be similar to the actuation magnets 112 of the mover 102, and a support body 222 also fixed to the structural frame 218. Similar to the support body 202 of the mover 180, the support body 222 is an axial / thrust bearing and includes a support surface 224 which is rotatable - relative to the structural frame 218 and the actuation magnets 220 - around a support rotation axis 226, a lower race 228 which includes the support surface 224, an upper race 230 which is fixed to the structural frame 218, and a plurality of bearing balls 232 which support rotation of the lower race 228 relative to the upper race 230 around the support rotation axis 226. When the mover 212 contacts the working surface 216 with the support surface 164, the support body 222 is generally configured to support the mover 212 for rotation, relative to the working surface 216, around a mover rotation axis 234 colinear with the support rotation axis 226. However, unlike the support body 202 of the mover 180, the support body 222 further includes a retaining shoulder 236 attached to the upper race 230 which may not be in contact with the lower race 228 during supported rotation, but which may contact the lower race 228 when the mover 212 is levitating to retain the lower race 228 the and the bearing balls 232 during levitation. That is, the retaining shoulder 236 may prevent the lower race 228 the and the bearing balls 232 from falling away from the upper race 230 during levitation of the mover 212. In some alternative embodiments similar to the embodiment shown in FIG. 6, the support body 222 may include an air bearing - including upper and lower races which are very smooth, flat surfaces and a film of air between the races during rotation - instead of or in addition to a ball bearing, and the retaining shoulder 236 may keep the lower air bearing race from separating during levitation of the mover 212.

[0066] Referring now to FIGS. 7 and 8, a displacement system according to another embodiment is shown generally at 240 and includes a mover 242, a stator device 244, and a controller (not shown). The stator device 244 may generally be similar to the stator device 104 of the displacement system 100 (i.e., of the embodiment of FIGS. 1 and 2), and includes one or more stators (not shown) and a working surface 246. The mover 242 is generally similar to the mover 102 of the of the displacement system 100 (i.e., of the embodiment of FIGS. 1 and 2), and includes a structural frame 248 similar to the structural frame 110 of the mover 102, actuation magnets 250 fixed to the structural frame 248 which may be similar to the actuation magnets 112 of the mover 102, and support bodies 252, 254, and 256 which also fixed to the structural frame 248. Unlike the support body 114 of the mover 102, the support bodies 252, 254, and 256 include wheels. The support body 252 includes a support surface 258 which is rotatable, relative to the structural frame 248 and the actuation magnets 250, around a support rotation axis 260 parallel to the support surface 258. Similarly, the support body 254 includes a support surface 262 which is rotatable, relative to the structural frame 248 and the actuation magnets 250, around a support rotation axis 264 parallel to the support surface 262. Likewise, the support body 256 includes a support surface 266 which is rotatable, relative to the structural frame 248 and the actuation magnets 250, around a support rotation axis 268 parallel to the support surface 266. When the mover 242 contacts the working surface 246 with the support surfaces 258, 262, and 266, the support bodies 252, 254, and 256 are generally configured to work in conjunction to support the mover 242 for rotation, relative to the working surface 246, around a mover rotation axis 270. Unlike the movers 102, 152, 182, and 212, the mover rotation axis 270 is not colinear with any of the support rotation axes 260, 264, or 268 - rather, in the embodiment shown in FIGS. 7 and 8, the mover rotation axis 270 is perpendicular to an intersection of the support rotation axes 260, 264, or 268. In alternative embodiments similar to the embodiment shown in FIGS. 7 and 8, the mover rotation axis 270 may be non-colinear with the support rotation axes 260, 264, or 268 but may not be perpendicular to an intersection of the support rotation axes 260, 264, or 268.

[0067] Referring now to FIGS. 9 and 10, a displacement system according to another embodiment is shown generally at 280 and includes a mover 282, a stator device 284, and a controller (not shown). The stator device 284 may generally be similar to the stator device 104 of the displacement system 100 (i.e., of the embodiment of FIGS. 1 and 2), and includes one or more stators (not shown) and a working surface 286. The mover 282 is generally similar to the mover 102 of the of the displacement system 100 (i.e., of the embodiment of FIGS. 1 and 2), and includes a structural frame 288 similar to the structural frame 110 of the mover 102, actuation magnets 290 fixed to the structural frame 288 which may be similar to the actuation magnets 112 of the mover 102, and a support body 292 also fixed to the structural frame 288. The support body 292 is generally similar to the support body 114 of the mover 102, and includes a support surface 294 which is rotatable, relative to the structural frame 288 and the actuation magnets 290, around a support rotation axis 296. Like the mover 202, the mover 282 includes a stator-facing surface 298 which is positioned to face the working surface 286 at least when the support surface 294 contacts the working surface 286. However, unlike the mover 102, the stator-facing surface 298 of the mover 282 defines a recess, shown generally at 300, which contains the support body 292 such that the support surface 294 is recessed from the stator-facing surface 298. The working surface 286 of the stator device 284 includes a protruding portion 302 which is sized and shaped to be received into the recess 300 such that when the mover 282 lands on the working surface 286 with the recess 300 aligned with the protruding portion 302 of the working surface 286, the protruding portion 302 is received into the recess 300 and contacts the support surface 296. When the mover 282 thus contacts the protruding portion 302 of the working surface 286 with the support surface 294, the support body 292 is generally configured to support the mover 282 for rotation, relative to the working surface 286, around a mover rotation axis 304 colinear with the support rotation axis 296. In the embodiment shown in FIGS. 9 and 10, the support surface 294 may only be able to contact the working surface 286 at the protruding portion 302. That is, if the mover 286 lands on the working surface 286 without the protruding portion 302 being received into the recess, then the support surface 294 may not contact the working surface 286.

[0068] Referring now to FIGS. 11 and 12, a displacement system according to another embodiment is shown generally at 310 and includes a mover 312, a stator device 314, and a controller (not shown). The stator device 314 may generally be similar to the stator device 104 of the displacement system 100 (i.e., of the embodiment of FIGS. 1 and 2), and includes one or more stators (not shown) and a working surface 316. The mover 312 is generally similar to the mover 102 of the of the displacement system 100 (i.e., of the embodiment of FIGS. 1 and 2), and includes a structural frame 318 similar to the structural frame 110 of the mover 102, and actuation magnets 320 fixed to the structural frame 318 which may be similar to the actuation magnets 112 of the mover 102. However, unlike in the displacement system 100, in the displacement system 310 shown in FIGS. 11 and 12, the stator device 314 includes a support body 322 which is attached to the working surface 316 and which is operable to support the mover 312 on the working surface 316. The support body 322 includes a support surface 324 which is rotatable relative to the working surface 316 around a support rotation axis 326 non-parallel to the working surface 316. More specifically, in the embodiment shown, the support rotation axis 326 is transverse to the working surface 316. Even more specifically, in the embodiment shown, the support rotation axis 326 is perpendicular to the working surface 316.

[0069] The support body 322 protrudes from the working surface 316 such that a stator-facing portion 328 of an external surface of the mover 312 may contact the stator device only at the support surface 324. When the stator-facing portion 328 of the external surface of the mover 312 contacts the support surface 324, the support body 322 - including the support surface 324 - may support the mover 312 for rotation, relative to the working surface 316, around the stator support axis 326. In operation, the controller may control the one or more stators of the stator device 314 to cause the mover 312 to contact the support surface 324, and may then further control the one or more stators to cause the mover 312 to rotate relative to the working surface 316 around the support rotation axis 326.

[0070] In the embodiment shown, the stator device 314 includes one ball bearing support body 322. However, alternative embodiments may include stator devices with one or more support bodies which may be or which may include bearings - such as mechanical bearings (including ball bearings and other rolling element bearings), sliding bearings, air bearings, and / or magnetic bearings - and / or wheels. Also, although the support body 322 of the embodiment shown in FIGS. 11 and 12 is recessed / embedded in the working surface 316, alternative embodiments may include support bodies which are not recessed / embedded in the working surface and which are instead located entirely above the working surface

[0071] Clauses

[0072] This disclosure includes but is not limited to the following clauses, which may be combined with other subject matter in this specification.

[0073] 1. A mover operable to move in response to at least one external magnetic field, the mover comprising: at least one actuation magnet, the at least one actuation magnet configured to generate forces for moving the mover in response to the at least one external magnetic field; and at least one support body comprising at least one support surface, the at least one support surface rotatable relative to the at least one actuation magnet, wherein the mover is positionable to contact, with at least the at least one support surface, a working surface of a stator device operable to generate the at least one external magnetic field.

[0074] 2. The mover of clause 1 wherein the mover is positionable to contact the working surface with at least the at least one support surface in response to the at least one external magnetic field.

[0075] 3. The mover of clause 1 wherein the mover is positionable to contact the working surface with only the at least one support surface.

[0076] 4. The mover of clause 3 wherein the mover is positionable to contact the working surface with only the at least one support surface in response to the at least one external magnetic field. 5. The mover of any one of clauses 1 to 4 wherein the at least one support surface is accessible from an exterior of the mover.

[0077] 6. The mover of any one of clauses 1 to 5 wherein the at least one support surface is at a periphery of the mover.

[0078] 7. The mover of any one of clauses 1 to 6 wherein the at least one support surface is around a periphery of the mover.

[0079] 8. The mover of any one of clauses 1 to 7 wherein the at least one support surface surrounds the at least one actuation magnet within at least one plane passing through the mover.

[0080] 9. The mover of any one of clauses 1 to 8 wherein the at least one support surface is planar.

[0081] 10. The mover of any one of clauses 1 to 8 wherein the at least one support surface is non-planar.

[0082] 11. The mover of clause 10 wherein the at least one support surface is curved.

[0083] 12. The mover of clause 10 or 11 wherein the at least one support surface is convex.

[0084] 13. The mover of any one of clauses 1 to 12 wherein the at least one support surface is rotatable relative to the at least one actuation magnet around a support rotation axis parallel to the at least one support surface.

[0085] 14. The mover of any one of clauses 1 to 12 wherein the at least one support surface is rotatable relative to the at least one actuation magnet around a support rotation axis non-parallel to the at least one support surface.

[0086] 15. The mover of clause 14 wherein the support rotation axis is transverse to the at least one support surface.

[0087] 16. The mover of clause 15 wherein the support rotation axis is perpendicular to the at least one support surface.

[0088] 17. The mover of any one of clauses 13 to 16 wherein each of the at least one actuation magnet is fixed relative to the support rotation axis. 18. The mover of any one of clauses 13 to 17 wherein the at least one support surface is rotatable relative to the at least one actuation magnet 360° around the support rotation axis.

[0089] 19. The mover of any one of clauses 1 to 18 wherein the at least one support body is configured to support the at least one actuation magnet for rotation relative to the working surface around a mover rotation axis when the at least one support surface contacts the working surface.

[0090] 20. The mover of clause 19 wherein, when the at least one support surface contacts the working surface, rotation of the at least one actuation magnet relative to the working surface around the mover rotation axis causes rotation of the at least one support surface relative to the at least one actuation magnet.

[0091] 21. The mover of clause 19 or 20 wherein the mover rotation axis is non-parallel to the working surface.

[0092] 22. The mover of clause 21 wherein the mover rotation axis is transverse to the working surface.

[0093] 23. The mover of clause 22 wherein the mover rotation axis is perpendicular to the working surface.

[0094] 24. The mover of any one of clauses 19 to 23 when directly or indirectly dependent from clause 13 or 14 wherein the mover rotation axis is colinear with the support rotation axis.

[0095] 25. The mover of any one of clauses 19 to 23 when directly or indirectly dependent from clause 13 or 14 wherein the mover rotation axis is non-colinear with the support rotation axis.

[0096] 26. The mover of any one of clauses 1 to 25 wherein the at least one support body is configured to support the mover against at least one force urging the mover toward the working surface when the at least one support surface contacts the working surface.

[0097] 27. The mover of clause 26 wherein the at least one support body is configured to support the mover against at least one moment generated by the at least one force when the at least one support surface contacts the working surface. 28. The mover of any one of clauses 1 to 27 wherein the at least one support body is configured to support at least some of a weight of the mover on the working surface when the at least one support surface contacts the working surface.

[0098] 29. The mover of clause 28 wherein the at least one support body is configured to support a majority of the weight of the mover on the working surface when the at least one support surface contacts the working surface.

[0099] 30. The mover of clause 29 wherein the at least one support body is configured to support all of the weight of the mover on the working surface when the at least one support surface contacts the working surface.

[0100] 31. The mover of clause 29 or 30 wherein the at least one support body is configured to support a majority of a combined weight of the mover and a payload carried by the mover on the working surface when the at least one support surface contacts the working surface.

[0101] 32. The mover of clause 31 wherein a weight of the payload is at least 75% of the weight of the mover.

[0102] 33. The mover of clause 31 or 32 wherein, when the at least one support surface contacts the working surface, a center of mass of the mover with the payload does not vertically overlap an interface between the at least one support surface and the working surface.

[0103] 34. The mover of any one of clauses 27 to 33 wherein a center of mass of the mover, when the at least one support surface contacts the working surface, a center of mass of the mover does not vertically overlap an interface between the at least one support surface and the working surface.

[0104] 35. The mover of any one of clauses 1 to 34 wherein the mover comprises an external surface comprising the at least one support surface.

[0105] 36. The mover of clause 35 wherein: the external surface further comprises at least one stator-facing surface positioned to face the working surface when the at least one support surface contacts the working surface, the at least one stator-facing surface defining at least one recess; and the at least one support surface is in the at least one recess and recessed from the at least one stator-facing surface.

[0106] 37. The mover of clause 35 wherein: the external surface further comprises at least one stator-facing surface positioned to face the working surface when the at least one support surface contacts the working surface; at least a portion of the at least one support body protrudes from the at least one statorfacing surface, the at least a portion of the at least one support body comprising the at least one support surface.

[0107] 38. The mover of clause 35, 36, or 37 when directly or indirectly dependent from clause 19 wherein: when the mover contacts the working surface with the at least one support surface, the mover is subject to a first resistance to rotation relative to the working surface around the mover rotation axis; when the mover contacts the working surface with at least one portion of the external surface other than the at least one support surface, the mover is subject to a second resistance to rotation relative to the working surface around the mover rotation axis; and the first resistance to rotation is less than the second resistance to rotation.

[0108] 39. The mover of any one of clauses 1 to 38 wherein the mover is operable to move in three degrees-of-freedom in response to the at least one external magnetic field.

[0109] 40. The mover of any one of clauses 1 to 38 wherein the mover is operable to move in six degrees-of-freedom in response to the at least one external magnetic field.

[0110] 41. The mover of any one of clauses 1 to 40 wherein the at least one actuation magnet comprises a plurality of actuation magnets.

[0111] 42. A stator device for a displacement system, the stator device comprising: at least one stator comprising at least one conductor positioned to generate at least one external magnetic field operable to move at least one mover of the displacement system; a working surface configured to be between the at least one mover and one or more of the at least one stator when the at least one mover is moving in response to the at least one external magnetic field; and at least one support body attached to the working surface, the at least one support body comprising at least one support surface, the at least one support surface rotatable relative to the working surface around a support rotation axis non-parallel to the working surface, the at least one support surface operable to support the at least one mover.

[0112] 43. The stator device of clause 42 wherein the support rotation axis is transverse to the working surface.

[0113] 44. The stator device of clause 43 wherein the support rotation axis is perpendicular to the working surface.

[0114] 45. The stator device of clause 42, 43, or 44 wherein the at least a portion of the at least one support body protrudes from the working surface.

[0115] 46. The stator device of any one of clauses 42 to 45 wherein the at least one conductor comprises at least one coil positioned to generate the at least one external magnetic field.

[0116] 47. The stator device of any one of clauses 42 to 46 further comprising an amplifier 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.

[0117] 48. The stator device of any one of clauses 42 to 47 wherein the at least one support surface is operable to support the at least one mover for rotation relative to the working surface around the support rotation axis.

[0118] 49. The mover of any one of clauses 1 to 41, or the stator device of any one of clauses 42 to 48, wherein the at least one support body comprises at least one bearing.

[0119] 50. The mover or the stator device of clause 49, wherein the at least one bearing comprises at least one mechanical bearing.

[0120] 51. The mover or the stator device of clause 50 wherein the at least one mechanical bearing comprises at least one rolling element bearing.

[0121] 52. The mover or the stator device of clause 51 wherein the at least one rolling element bearing comprises at least one ball bearing.

[0122] 53. The mover or the stator device of any one of clauses 49 to 52 wherein the at least one bearing comprises at least one sliding bearing. 54. The mover or the stator device of any one of clauses 49 to 53 wherein the at least one bearing comprises at least one air bearing.

[0123] 55. The mover or the stator device of any one of clauses 49 to 54 wherein the at least one bearing comprises at least one magnetic bearing.

[0124] 56. The mover of any one of clauses 1 to 41 or 49 to 55, or the stator device of any one of clauses 42 to 55, wherein the at least one support body comprises at least one wheel.

[0125] 57. The mover of any one of clauses 1 to 41 or 49 to 56, or the stator device of any one of clauses 42 to 56, wherein: the at least one support body comprises a plurality of support bodies; the at least one support surface comprises a plurality of support surfaces; and each of the plurality of support bodies comprises one or more of the plurality of support surfaces.

[0126] 58. A displacement system comprising: the mover of any one of clauses 1 to 41 or 49 to 57; and a stator device comprising: at least one stator comprising at least one conductor positioned to generate the at least one external magnetic field; and a working surface configured to be between the mover and one or more of the at least one stator when the mover is moving in response to the at least one external magnetic field.

[0127] 59. A displacement system comprising: the mover of any one of clauses 1 to 41or 49 to 57; and the stator device of any one of clauses 42 to 57.

[0128] 60. The displacement system of clause 58 or 59 when directly or indirectly dependent from clause 36 wherein the working surface of the stator device comprises at least one protruding portion sized and shaped to be received into the at least one recess of the mover to contact the at least one support surface.

[0129] 61. The displacement system of clause 60 wherein the at least one support surface can only contact the working surface at the at least one protruding portion.

[0130] 62. A displacement system comprising: the stator device of any one of clauses 42 to 57; and a mover operable to move in response to the at least one external magnetic field.

[0131] 63. The displacement system of any one of clauses 58 to 62 further comprising a controller configured to control the at least one stator to generate the at least one external magnetic field operable to move the mover.

[0132] 64. The displacement system of clause 63 when directly or indirectly dependent from clause 1 wherein the controller is configured to control the at least one stator to cause the mover to contact the working surface with the at least one support surface of the mover.

[0133] 65. The displacement system of clause 64 wherein the controller is further configured to, at least when the at least one support surface contacts the working surface, control the at least one stator to cause the mover to rotate the at least one actuation magnet relative to the working surface.

[0134] 66. The displacement system of clause 63, 64, or 65 when directly or indirectly dependent from clause 42 wherein the controller is configured to control the at least one stator to cause the mover to contact the at least one support surface of the stator device.

[0135] 67. The displacement system of clause 66 wherein the controller is further configured to, at least when the mover contacts the at least one support surface, control the at least one stator to cause the mover to rotate relative to the working surface around the support rotation axis.

[0136] 68. The displacement system of clause 65 or 67 wherein the controller is configured to, when controlling the at least one stator to cause the mover to rotate relative to the working surface, control the at least one stator to maintain an orientation of the mover relative to the working surface.

[0137] 69. The displacement system of any one of clauses 63 to 68 wherein the controller is further configured to control the at least one stator to cause the mover to move over the working surface at a levitation distance away from the working surface, the levitation distance greater than a length of any protrusion from the working surface.

[0138] 70. A method of operating the displacement system of clause 58, 59, or 60, the method comprising causing the at least one stator to cause the mover to contact the working surface with the at least one support surface of the mover. 71. The method of clause 68 further comprising, when the at least one support surface contacts the working surface, causing the at least one stator to cause the mover to rotate the at least one actuation magnet relative to the working surface.

[0139] 72. A method of operating the displacement system of clause 59 or 61, or of clause 60 when directly or indirectly dependent from clause 59, the method comprising causing the at least one stator to cause the mover to contact the at least one support surface of the stator device.

[0140] 73. The method of clause 72 further comprising, when the mover contacts the at least one support surface, causing the at least one stator to cause the mover to rotate relative to the working surface around the support rotation axis.

[0141] 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 mover operable to move in response to at least one external magnetic field, the mover comprising: at least one actuation magnet, the at least one actuation magnet configured to generate forces for moving the mover in response to the at least one external magnetic field; and at least one support body comprising at least one support surface, the at least one support surface rotatable relative to the at least one actuation magnet, wherein the mover is positionable to contact, with at least the at least one support surface, a working surface of a stator device operable to generate the at least one external magnetic field.

2. The mover of claim 1 wherein the mover is positionable to contact the working surface with only the at least one support surface.

3. The mover of claim 1 or 2 wherein the at least one support surface is rotatable relative to the at least one actuation magnet around a support rotation axis parallel to the at least one support surface.

4. The mover of claim 1, 2, or 3 wherein the at least one support surface is rotatable relative to the at least one actuation magnet around a support rotation axis non-parallel to the at least one support surface.

5. The mover of claim 3 or 4 wherein each of the at least one actuation magnet is fixed relative to the support rotation axis.

6. The mover of any one of claims 1 to 5 wherein the at least one support body is configured to support the at least one actuation magnet for rotation relative to the working surface around a mover rotation axis when the at least one support surface contacts the working surface.

7. The mover of claim 6 wherein the mover rotation axis is non-parallel to the working surface.

8. The mover of claim 6 or 7 when directly or indirectly dependent from claim 3 or 4 wherein the mover rotation axis is colinear with the support rotation axis.

9. The mover of any one of claims 6 or 7 when directly or indirectly dependent from claim 3 or 4 wherein the mover rotation axis is non-colinear with the support rotation axis.

10. The mover of any one of claims 1 to 9 wherein the at least one support body is configured to support the mover against at least one force urging the mover toward the working surface when the at least one support surface contacts the working surface.

11. The mover of any one of claims 1 to 10 wherein the mover comprises an external surface comprising the at least one support surface.

12. The mover of claim 11 wherein: the external surface further comprises at least one stator-facing surface positioned to face the working surface when the at least one support surface contacts the working surface, the at least one stator-facing surface defining at least one recess; and the at least one support surface is in the at least one recess and recessed from the at least one stator-facing surface.

13. The mover of claim 11 wherein: the external surface further comprises at least one stator-facing surface positioned to face the working surface when the at least one support surface contacts the working surface; at least a portion of the at least one support body protrudes from the at least one statorfacing surface, the at least a portion of the at least one support body comprising the at least one support surface.

14. A stator device for a displacement system, the stator device comprising: at least one stator comprising at least one conductor positioned to generate at least one external magnetic field operable to move at least one mover of the displacement system;a working surface configured to be between the at least one mover and one or more of the at least one stator when the at least one mover is moving in response to the at least one external magnetic field; and at least one support body attached to the working surface, the at least one support body comprising at least one support surface, the at least one support surface rotatable relative to the working surface around a support rotation axis non-parallel to the working surface, the at least one support surface operable to support the at least one mover.

15. The stator device of claim 14 wherein the at least a portion of the at least one support body protrudes from the working surface.

16. The mover of any one of claims 1 to 13, or the stator device of claim 14 or 15, wherein: the at least one support body comprises a plurality of support bodies; the at least one support surface comprises a plurality of support surfaces; and each of the plurality of support bodies comprises one or more of the plurality of support surfaces.

17. A displacement system comprising: the mover of any one of claims 1 to 13; and the stator device of claim 14 or 15.

18. The displacement system of claim 17 when directly or indirectly dependent from claim 12 wherein the working surface of the stator device comprises at least one protruding portion sized and shaped to be received into the at least one recess of the mover to contact the at least one support surface.

19. A method of operating the displacement system of claim 17 or 18, the method comprising causing the at least one stator to cause the mover to contact the working surface with the at least one support surface of the mover.

20. A method of operating the displacement system of claim 17 or 18, the method comprising causing the at least one stator to cause the mover to contact the at least one support surface of the stator device.

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