Patent Description:
Motion stages (e.g. XY tables and rotary tables) are widely used in various manufacturing, inspection, and assembling processes. A common solution currently in use achieves XY motion by stacking together two linear stages (e.g. an X-stage and a Y-stage) via connecting bearings. A more desirable solution involves having a single moving stage capable of XY motion, eliminating the need for additional bearings. It might also be desirable for such a moving stage to be able to provide at least some Z motion. Attempts have been made to design such displacement devices using the interaction between current-carrying coils and permanent magnets. For example, a magnetic mover may be displaced relative to stator operable to generate one or more magnetic fields.

One problem with such systems, however, is that it may be difficult for a controller of the stator to distinguish one mover on the stator from other movers on the stator.

<CIT> describes a movement device with a stator and at least one body movable relative to the stator, the stator having a movement surface and the movable body adjacent to the movement surface. <CIT> describes magnetically moveable displacement devices or robotic devices.

<CIT> describes a transport device comprising at least one mover, which comprises at least several permanent magnets, the permanent magnets interacting with at least one coil level of a drive surface for driving the mover, and at least one permanent magnet being designed as a plastic-bonded magnet.

Generally, according to embodiments of the disclosure, there is described a system comprising one or more magnetic movers and one or more stators. A stator defines a work surface, for example a 2D planar work surface, and comprises an actuation coil assembly for driving movement of the one or more magnetic movers over the work surface. The stator comprises at least one stator identification device which is a stator coupling coil. A magnetic mover comprises at least a first magnetically responsive unit (<NUM>st MRU) and at least one mover identification device (a second magnetically responsive unit or (<NUM>nd MRU). The stator coupling coil and the <NUM>nd MRU, and more generally the stator identification device and the mover identification device, are operable to interact with one another, for example through magnetic induction. According to some embodiments, rather than using magnetic induction, interaction between the stator identification device and the mover identification
device may be active rather than passive. For example, the stator identification device may initiate communication with the mover identification device and request that the mover identification device transmit identification or other information to the stator identification device. Alternatively, the mover identification device may periodically transmit identification or other information to the stator identification device, for example.

The system further comprises one or more sensors for sensing a position of the magnetic mover.

Based on the position of the magnetic mover, a controller may control one or more stator driving circuits to drive the actuation coil assembly to thereby move the magnetic mover over the work surface. In particular, the actuation coil assembly interacts with one or more magnetic components (such as one or more magnet arrays) on the mover to cause movement of the mover over the work surface. The movement is in at least two or more degrees of freedom, for example in the x and y directions.

According to a first aspect of the invention, there is provided a system according to claim <NUM>.

According to a second aspect of the invention, there is provided a method according to claim <NUM>. Particular embodiments of the invention are described in dependent claims <NUM>-<NUM>.

This summary does not necessarily describe the entire scope of all aspects. Other aspects, features and advantages will be apparent to those of ordinary skill in the art upon review of the following description of specific embodiments.

In the accompanying drawings, which illustrate one or more example embodiments:.

The present disclosure seeks to provide improved systems and methods for identifying a magnetic mover. While various embodiments of the disclosure are described below, the disclosure is not limited to these embodiments, and variations of these embodiments may well fall within the scope of the disclosure which is to be limited only by the appended claims.

Throughout the following description, specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, elements well known in the prior art may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense.

According to some embodiments, robotic devices (or systems) are provided and which comprise one or more stators and one or more movers. Each mover may carry one or more workpieces or parts (workpieces and parts are used interchangeably throughout this disclosure). In some applications, a plurality of movers may carry one part holder, which may hold one or more parts. A "part" is a general term, and non-limiting examples include a component, a sample, or an assembly. Generally, a stator and one or more movers may interact with each other via one or more magnetic fields so that the stator can provide forces and/or torques to the one or more movers to controllably move the one or more movers. In some embodiments, all movers in a system are substantially similar or nearly identical; however, this is not essential, and a system may comprise movers comprising magnet arrays of different size and/or configuration. In some embodiments, a stator may comprise a plurality of coils distributed in one or more planar layers. In some embodiments, a stator may further comprise a plurality of teeth, such as iron teeth.

The stator provides a work surface (which may have any of various suitable shapes, such as, flat, curved, cylindrical, or spherical), and each mover is able to move along, over, or on the work surface either in a contacting manner (via one or more contacting media such as sliding and/or rolling bearings, contact mode, or sitting mode) or without any contact by maintaining a controllable gap between a mover and a stator in a normal direction of the work surface. Such a gap may be maintained by passive or active levitation means.

Throughout this disclosure, moveable motion stages, moveable stages, motion stages, and movers are used interchangeably. Each mover may comprise one or more magnet assemblies. Each magnet assembly may comprise one or more magnet arrays rigidly connected together. Each magnet array may comprise one or more magnetization elements. Each magnetization element has a magnetization direction. Generally, magnets on a mover interact with stator coils via a working gap that is much smaller than a lateral dimension of the mover, i.e. a dimension parallel with the stator work surface.

In some embodiments, one or more amplifiers may be connected to drive a plurality of currents in the plurality of coils in the one or more stators. One or more controllers may be connected to deliver control signals to the one or more amplifiers. The control signals may be used to control current driven by the one or more amplifiers into at least some of the plurality of coils. The currents controllably driven into the at least some of the plurality of coils create magnetic fields which cause corresponding magnetic forces on the one or more magnet assemblies of a mover, thereby moving the mover relative to the stator (e.g. over or on the work surface) controllably in at least <NUM> in-plane degrees-of-freedom (DOF), or at least <NUM> in-plane DOFs, or at least <NUM> DOFs. In some embodiments, the magnetic forces associated with the interaction between the magnetic fields created by the currents in at least some of the coils and the magnetic fields associated with the magnet arrays may attract the moveable stage toward the stator when the controller is controlling the currents driven by the one or more amplifiers. In some embodiments, the magnetic forces associated with the interaction between the magnetic fields created by the currents in at least some of the coils and the magnetic fields associated with the magnet arrays may force the mover stage away from the stator to balance gravitational forces with an air gap when the controller is controlling the currents driven by the one or more amplifiers. In some embodiments, the gap between the movers and the stator is maintained by air bearings or compressed-fluid bearings.

In some embodiments, movers may work in levitation mode, i.e. movers may be levitated near the work surface without contacting the work surface either in a passive way or in an active way, and movers <NUM> may move along the work surface extending in X and Y directions, where X and Y are two in-plane, non-parallel directions. The separation gap between the work surface and a mover is generally much smaller than dimensions of the mover in both the X and the Y directions. Although in some embodiments movers are capable of <NUM> DOF controllable motion, this is not essential. In certain applications, where levitation of a mover may not be required and heavy load-carrying capability is more important, it will be understood by those of skill in the art that movers can sit on the work surface with proper mechanical bearings (including but not being limited to planar sliding bearings and ball transfer units), and are capable of three in-plane DOF controllable motion (translation in the X and Y directions, and rotation around the Z direction), where the X and Y directions are two in-plane, non-parallel direction, and the Z direction is normal to the work surface. When a mover relies on sliding and/or rolling bearings to sit on the work surface and the mover is capable of <NUM> in-plane DOF controllable motion (translation in the X and Y directions, and rotation around the Z direction), it is working in a <NUM>-DOF controlled sitting mode. In some embodiments, a mover is capable of <NUM>-DOF controllable motion (translation in the X and Y directions, and rotation around the Z direction) while working in levitation mode without contact with the stator; in this mode, translation in the Z direction, and rotation around the X and Y directions are open-loop controlled without feedback, using suitable passive levitation technology known to those of skill in the art. When a mover is capable of <NUM>-DOF controllable motion without contact with the stator, it is working in a <NUM>-DOF controlled levitation mode.

Generally, a stator working region is a two-dimensional (2D) area provided by the stator work surface, and movers can be controllably moved with at least two in-plane DOFs inside the stator working region, with suitable feedback control algorithms and suitable position feedback sensors.

For the purposes of describing the movers disclosed herein, it can be useful to define a pair of coordinate systems - a stator coordinate system which is fixed to the stator (e.g. to stator <NUM> of <FIG>); and a mover coordinate system which is fixed to the moveable stage (e.g. mover <NUM> of <FIG>) and moves with the mover relative to the stator and the stator coordinate system. This description may use conventional Cartesian coordinates (x, y, z) to describe these coordinate systems, although it will be appreciated that other coordinate systems could be used. For convenience and brevity, in this 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 the mover-x (or Xm), mover-y (Ym) and mover-z (or Zm) directions, respectively. Accordingly, this description and the associated drawings may refer to directions (e.g. x, y, and/or z) to refer to directions in both or either of the stator and mover coordinate systems. However, it will be appreciated from the context of the description herein that in some embodiments and/or circumstances, a mover (e.g. mover <NUM>) may move relative to a stator (e.g. stator <NUM>) such that these stator and mover directions are no longer coincident with one another. In such cases, this disclosure may adopt the convention of using the terms stator-x, stator-y and stator-z to refer to directions and/or coordinates in the stator coordinate system, and the terms mover-x, mover-y and mover-z to refer to directions and/or coordinates in the mover coordinate system. In this description and the associated drawings, 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 ±<NUM>° in some embodiments; within ±<NUM>° in some embodiments; and within ±<NUM>° in some embodiments). Although in this description the work surface is essentially flat and planar, it will be understood to those skilled in the art that this is not essential and that the work surface of the stator (e.g. the surface facing movers) can be a curved surface including but not being limited to a cylindrical surface or a spherical surface, with suitable modification of control algorithms and stator coil layout disclosed herein.

In some embodiments, the stator-x and stator-y directions are non-parallel. In particular embodiments, the stator-x and stator-y directions are generally orthogonal. In some embodiments, the mover-x and mover-y directions are non-parallel. In particular embodiments, the mover-x and mover-y directions are generally orthogonal. In some embodiments, the stator-x and stator-y directions are parallel with the stator work surface, and the stator-z direction is normal to the stator work surface.

<FIG> shows a robotic system <NUM> according to a particular embodiment. <FIG> shows a side view of the system <NUM>. The robotic system <NUM> comprises a stator <NUM> and a mover <NUM>, one or more controllers <NUM>, and one or more sensors <NUM> (not shown) for providing position feedback signals. The stator <NUM> comprises a stator actuation coil assembly <NUM> and a stator coupling coil assembly <NUM>. The mover <NUM> comprises at least a first magnetically responsive unit (<NUM>st MRU) <NUM> and a second magnetically responsive unit (<NUM>nd MRU) <NUM>. The stator actuation coil assembly <NUM> comprises a plurality of actuation coil circuits <NUM>. Actuation coil circuits <NUM> may be driven with suitable currents by stator driving circuits, which generate magnetic fields interacting with the <NUM>st MRU to move the mover <NUM> in at least two in-plane degrees of freedom (such as but not being limited to linear motion in the X and Y directions). The stator coupling coil assembly <NUM> comprise one or more coupling coil circuits <NUM> which can create magnetic field coupling with the <NUM>nd MRU <NUM> for the purpose of transfer of energy or information. In some embodiments, coupling coil circuits <NUM> and <NUM>nd MRU <NUM> overlap with each other in the Z direction. However, this is not essential. In some embodiments, the <NUM>nd MRU <NUM> overlaps with an effective stator coupling coil region <NUM>, which generally extends beyond the footprint of stator coupling coil assembly <NUM> by <NUM>-<NUM>% of the linear dimension of stator coupling coil assembly <NUM> in X and Y directions, respectively, as shown in <FIG>. In some embodiments, the effective stator coupling coil region <NUM> has a footprint that is smaller than the coupling coil assembly <NUM>'s footprint. In some embodiments, a single coupling coil assembly <NUM> may have more than one effective stator coupling coil region <NUM>, as shown in <FIG>. In one example, when the <NUM>nd MRU <NUM> overlaps with the effective stator coupling coil region <NUM> in the Z direction, the coupling between <NUM>nd MRU <NUM> and coupling coil circuits <NUM> is very strong and may alter the coupling coil mutual inductance significantly in comparison with that in a weak coupling (e.g. when the <NUM>nd MRU <NUM> has little or no overlap with the effective stator coupling coil region <NUM> in the Z direction). In one example, bidirectional transfer of power/information between stator coupling coil assembly <NUM> and <NUM>nd MRU <NUM> includes bidirectional information transfer. In another example, bidirectional transfer of power/information between stator coupling coil assembly <NUM> and <NUM>nd MRU <NUM> includes power transfer in one direction (such as from stator coupling coil assembly <NUM> to <NUM>nd MRU <NUM>) and information transfer in another direction (such as from <NUM>nd MRU <NUM> to stator coupling coil assembly <NUM>).

The coupling coil circuits <NUM> are driven with currents at a base frequency significantly higher than the base frequencies of currents flowing into the actuation coil circuits <NUM>. In one non-limiting example, the base frequency of currents in actuation coil circuits <NUM> are in the range of a few hundred hertz or less, while the base frequency of currents in coupling circuits <NUM> are in the range of tens of kHz or higher. The coupling coil circuits <NUM> are driven with currents of amplitudes significantly lower than the amplitude of currents driven into the actuation coil circuits <NUM>. In one non-limiting example, the amplitude of currents in the actuation coil circuits <NUM> is in the range of amperes or higher, while the amplitude of currents in the coupling coil circuits <NUM> is in the range of milliamperes or lower. The coupling coil circuits <NUM> have a geometry (shape and/or coil width) significantly different from the actuation coil circuits <NUM>. For example, the coil circuits <NUM> may be linearly elongated in the X or Y directions; the coil circuits <NUM> may be have a rectangular, square, circular, or any other suitable shape in the plane extending in the X or Y directions.

In one non-limiting example, the <NUM>st MRU <NUM> comprises a magnet array suitably designed so that the interaction between the actuation coil currents and the <NUM>st MRU <NUM> via magnetic fields can controllably move the mover <NUM> in at least two degrees of freedom.

In one non-limiting example, the <NUM>nd MRU <NUM> comprises an inductive coil and a capacitor, the inductive coil and the capacitor suitably connected to form a resonance circuit to facilitate bidirectional transfer of power or information. In some embodiment, the <NUM>nd MRU <NUM> may transfer its internally stored information to the coupling coil circuit <NUM>, by demodulating the terminal voltage or currents of the coupling coil circuit <NUM>.

In one non-limiting example, the <NUM>nd MRU <NUM> comprises a material of high electrical conductivity, such as but not being limited to copper or gold, so that the coupling between the <NUM>nd MRU <NUM> and the coupling coil circuit <NUM> significantly weakens the inductance of the coupling coil circuit <NUM>, such as by <NUM>% or more. The inductance change (reduction) can be used to indicate whether the <NUM>nd MRU <NUM> is located above the coupling coil circuit <NUM> for detecting the mover's in-plane orientation (its angular rotation relative to the Z axis).

In one non-limiting example, the <NUM>nd MRU <NUM> may comprise a magnetic core made of material(s) of high magnetic permeability, such as but not being limited to iron and/or nickel, so that the coupling between the <NUM>nd MRU <NUM> and the coupling coil circuit <NUM> is strengthened. In this embodiment, the inductive coil of the <NUM>nd MRU <NUM> is wound around the magnetic core.

One non-limiting example of actuation coil circuits <NUM> and/or coupling coil circuits <NUM> are traces manufactured with PCB fabrication technology.

In some embodiments, the actuation coil circuits <NUM> and the coupling coil circuits <NUM> overlap with each other in the stator Z direction, but are located at different Z positions, so that the coupling coil circuits <NUM> do not interrupt the continuity of actuation coil circuits <NUM>, and the mover <NUM> can be actuated smoothly during its planar motion in at least two planar degrees of freedom.

The actuation coil circuits <NUM> and the coupling coil circuits <NUM> are intentionally designed or created in such a way to minimize the cross-coupling between the coupling coil circuits <NUM> and the <NUM>st MRU <NUM>, and/or the cross-coupling between the actuation coil circuits <NUM> and the <NUM>nd MRU <NUM>.

The mover <NUM> is controllably moveable along a work surface <NUM>, which is the top surface of stator <NUM> extending in the X and Y directions. Due to the fact that the actuation coil circuits <NUM> and the coupling coil circuits <NUM> are separated from the mover <NUM> by the work surface <NUM>, the mover <NUM>'s planar motion in the X and Y directions is not mechanically constrained by the actuation coil circuits <NUM> or the coupling coil circuits <NUM>.

The stator <NUM> comprises a controller <NUM>. The controller <NUM> may receive signals from position sensors <NUM> (not shown in <FIG>) to generate suitable currents flowing into the actuation coil circuits <NUM> to controllably move the mover <NUM> in the X and Y directions. The controller <NUM> may also generate suitable currents flowing through the coupling coil circuits <NUM> or apply a suitable voltage on the coupling coil circuits <NUM> to interact with the <NUM>nd MRU <NUM> for the purpose of wireless transfer of power or information or for the purpose of detecting the absence/presence of <NUM>nd MRU <NUM>. The controller <NUM> may also detect or measure the terminal voltage and/or currents in the coupling coil circuits <NUM> for information receiving. Controller <NUM> and sensors <NUM> may be configured or connected for controllably moving movers <NUM> relative to a stator <NUM> along a work surface <NUM> either in contact mode or in noncontact mode by separating the mover <NUM> from the work surface <NUM> with a Z oriented gap. For example, controller <NUM> may be configured to receive signals from sensors <NUM> and generate currents flowing through the coil traces inside the stator actuation coil assembly <NUM> according to suitable algorithms. Generally, controller <NUM> comprises power electronics (power amplifiers) to generate the suitable currents.

The mover <NUM> may be controllably moved relative to the stator <NUM> by the interaction between the stator actuation coil assembly <NUM> and the <NUM>st MRU <NUM> about a working region in at least two in-plane DOFs. In some embodiments, mover <NUM> is capable of <NUM>-DOF controllable motion (X, Y, Z, Rx, Ry, and Rz); in some embodiments, mover <NUM> is capable of three in-plane DOF controllable motion (X, Y, and Rz), in a passive levitation mode or in a sitting mode.

Although only one mover <NUM> is shown in <FIG>, it should be understood to those skilled in the art that a system may comprise one or more movers. Although only one stator <NUM> is shown in <FIG>, this is not essential as it will become apparent that a robotic system may comprise more than one stator.

<FIG> shows a side view of a non-limiting example of actuation coil circuits <NUM> and coupling coil circuits <NUM>. In this embodiment, actuation coil circuits <NUM> and coupling coil circuits <NUM> overlap with each other in the stator Z direction.

As shown in <FIG>, actuation coil circuits <NUM> comprise multiple (four in the embodiment of <FIG>) layers of coil circuits (51a, 51b, 51c, and 51d). <FIG> shows a non-limiting example of the layer 51a comprising a plurality of Y-oriented coils traces 53a, each coil trace 53a having a width 52a. <FIG> shows a non-limiting example of layer 51b, comprising a plurality of X-oriented coil trace 53b, each with a width 52b. As a non-limiting example shown in <FIG>, coupling coil circuits <NUM> comprise two layers of coil circuit 61a and 61b. Generally, coupling coil circuits <NUM> comprise one or more layers. <FIG> shows a non-limiting example of trace layers 61a and 61b. The traces in different trace layers 61a and 61b are connected by vias (not shown) in series or in parallel to increase the magnetic coupling to <NUM>nd MRU <NUM>. One possible way to make coupling coil circuits <NUM> is to use printed circuit board fabrication technology. Although two layers of coil traces 61a and 61b are shown in <FIG>, this is not essential. Generally, coupling coil circuits <NUM> may comprise one or more layers of coil traces, and each layer may comprise one or more turns of coil traces (circuits).

It should be noted that the actuation coil circuits <NUM> and the coupling coil circuits <NUM> are substantially different from each other in geometry. In some embodiment, the width <NUM> of coil traces in the coupling coil circuits <NUM> is substantially smaller than the width <NUM> of coil traces in the actuation coil circuits <NUM>. In some embodiments, the shape of coil traces in the coupling coil circuits <NUM> is substantially different from the shape of coil traces in the actuation coil circuits <NUM>. For example, the traces (circuits) in the coupling coil circuits <NUM> may be in square, circular, triangular, rectangular, or polygonal shapes; traces in the actuation coil circuits <NUM> may be linearly elongated. A reason for the different geometry is that these two groups of coil traces in the actuation coil circuits <NUM> and the coupling coil circuits <NUM> are used to carry currents of significantly different frequencies and significantly different amplitudes.

<FIG> shows a schematic top view of mover <NUM> according to one embodiment of the disclosure. Mover <NUM> comprises a <NUM>st MRU <NUM> and four <NUM>nd MRU 20A, 20B, 20C, 20D. Although four <NUM>nd MRU <NUM> are shown in <FIG>, this is not essential. In some embodiments, a mover <NUM> may comprise one <NUM>nd MRU <NUM>; in some embodiments, a mover <NUM> may comprise two <NUM>nd MRU <NUM>. Generally, a mover <NUM> may comprise one or more <NUM>nd MRU <NUM>. Although <NUM>nd MRUs <NUM> are located at the periphery of <NUM>st MRU <NUM> as shown in <FIG> and <FIG>, this is not essential. In some embodiments, there may exist a magnet-free space in the center of <NUM>st MRU <NUM>'s footprint relative to the stator work surface <NUM>, in which there is no magnet; the <NUM>nd MRU <NUM> may be located in such a magnet-free space, as discussed later.

<FIG> shows a non-limiting example of a <NUM>nd MRU <NUM> which comprises an inductive coil <NUM>, a magnetic field enhancement core (or a magnetic core) <NUM> that is made of materials with high magnetic permeability, and a processing unit <NUM>. The processing unit <NUM> may comprise one or more capacitors so that the one or more capacitors and the inductive coil <NUM> form a resonant circuit with a resonance frequency tuned to be consistent with the frequency of excitation currents in coupling coil circuits <NUM> to facilitate power or information transmission with high efficiency from the stator <NUM> to the mover <NUM>. In some embodiments, the processing unit <NUM> may additionally comprise one or more modulating circuits and one or more information storage components. The modulation circuit allows the transfer of the information stored in the information storage component from the mover <NUM> to the stator <NUM>. During the information and/or power transfer process between <NUM>nd MRU <NUM> and coupling coil assembly <NUM>, the magnetic core <NUM> is used to guide and enhance the magnetic flux encircled by the inductive coil <NUM>. The magnetic core axial direction <NUM> is the direction of the magnetic core orientation and also the direction around which the inductive coil <NUM> is wound based on the right-hand rule. The magnetic flux is guided along the axial direction inside the magnetic core <NUM>. Although the magnetic core axial direction <NUM> is an arrow pointing to the left, it should be understood to those of skill in the art that the actual AC flux may be in direction <NUM> or opposite to direction <NUM>. Therefore, the magnetic core axial direction <NUM> is referred as the <NUM>nd MRU flux generation axial direction. It should be noted that the magnetic flux generated from the stator coupling coil assembly <NUM> can achieve the best coupling to the inductive coil <NUM> when the flux generated by the coupling coil assembly <NUM> is aligned with the <NUM>nd MRU flux generation axial direction. Therefore, the axial direction <NUM> is a preferred direction for <NUM>nd MRU flux generation and for detecting flux by the coupling coil circuits <NUM>. Generally, it is preferred that the flux generated by <NUM>st MRU <NUM> does not saturate the magnetic core <NUM> of the <NUM>nd MRU <NUM> in the axial direction; otherwise, the coupling effect (and thus power transfer and information transfer) between the <NUM>nd MRU <NUM> and the stator coupling coil assembly <NUM> will be impaired because, if the magnet core <NUM> is saturated or close to being saturated in its axial direction, the effective permeability of the magnetic core is significantly reduced.

<FIG> shows one non-limiting example of coupling coil circuits <NUM>: the coil circuits contain multiple turns placed in a plane with its normal direction in the Z direction. <FIG> shows another non-limiting example of the coupling coil circuits <NUM>: the coil circuits contain multiple turns located in a plane with its normal direction in the Y direction. <FIG> shows the effective stator coupling coil region <NUM> relative to the coupling coil circuits <NUM>.

<FIG> shows another embodiment according to the disclosure. In this embodiment, the stator <NUM> comprises multiple coupling coil assemblies <NUM> and two movers: 100A and 100B. Using controller <NUM>, movers 100A and 100B can be driven to two separate locations, such that the <NUM>nd MRU of mover 100A will interact with the stator coupling coil assembly 60A, and the <NUM>nd MRU of mover 100B will interact with the stator coupling coil assembly 60B. Thus, it is possible to simultaneous receive data from the <NUM>nd MRU of movers 100A and 100B.

In some embodiments, the coupling between the coupling coil circuits <NUM> and the <NUM>nd MRU <NUM> is used to detect the presence or absence of <NUM>nd MRU <NUM> above coupling coil assembly <NUM>. The inductance of coupling coil assembly <NUM> will differ greatly between the case of <NUM>nd MRU <NUM> being located above coupling coil assembly <NUM> as opposed to the case of <NUM>nd MRU <NUM> not being located above coupling coil assembly <NUM>. Such characteristics may be used to detect the presence of mover <NUM> and/or the orientation of mover <NUM>, as explained later in connection with <FIG>.

According to the invention, the stator coupling coil assembly <NUM> can transfer power/energy to <NUM>nd MRU <NUM> when effective stator coupling coil region <NUM> and <NUM>nd MRU <NUM><NUM> are overlapping with each other in the stator Z direction. With the received energy from stator coupling coil assembly <NUM>, <NUM>nd MRU <NUM> can transmit its stored information to coupling coil assembly <NUM> by exciting its inductive coil <NUM> with information-carrying AC current <NUM> to produce a magnetic flux that is coupled to the coupling coil circuits <NUM>, and the coupled flux will induce electrical voltage on the coupling coil circuits <NUM>. In some embodiments, each <NUM>nd MRU <NUM> may store unique identification information so that coupling coil assembly <NUM> may detect whether a <NUM>nd MRU <NUM> is within its effective stator coupling coil region <NUM> (in other words, <NUM>nd MRU <NUM> and effective stator coupling coil region <NUM> are overlapping in the Z direction), but also can detect exactly which <NUM>nd MRU <NUM> is within its effective stator coupling coil region <NUM>.

In some embodiments, each mover <NUM> may only be able to be rotated around Rz for a relatively small angle range such as +/- <NUM> degrees or less. However, there may exist multiple possible Rz orientation ranges, including but not limited to <NUM> +/-<NUM> degrees, <NUM> +/-<NUM> degrees, <NUM> +/-<NUM> degrees, and <NUM> +/-<NUM> degrees. In order to determine the absolute Rz orientation (e.g. distinguish which Rz orientation range the mover <NUM> is actually in), one method is described in connection with <FIG> show one embodiment according to the disclosure. One mover <NUM> comprises four second magnetically responsive units 20A, 20B, 20C, and 20D. Each of the four <NUM>nd MRUs <NUM> stores unique identification information related to mover <NUM>. When the mover center <NUM> is positioned at a determining location (x0, y0), one of the <NUM>nd MRUs <NUM> will overlap with the effective stator coupling coil region <NUM> in the Z direction. By detecting the specific <NUM>nd MRU <NUM> above effective stator coupling coil region <NUM>, the system controller <NUM> can determine which one of the four possible orientations (<FIG>) the mover <NUM> is positioned in.

In <FIG>, a star is used to represent the mover Rz absolute orientation. In <FIG>, when the mover center <NUM> is moved to (x0, y0), <NUM>nd MRU 20A will overlap with effective stator coupling coil region <NUM> and the unique information stored in <NUM>nd MRU 20A can be transferred to coupling coil assembly <NUM>, and accordingly the controller <NUM> can detect the mover Rz absolute orientation. <FIG> shows another possible orientation of mover <NUM> with the star in the positive Y direction relative to the mover center <NUM>. When the mover center <NUM> is moved to (x0, y0), <NUM>nd MRU 20D will overlap with effective stator coupling coil region <NUM> and the unique information stored in <NUM>nd MRU 20D can be transferred to coupling coil assembly <NUM>, and accordingly the controller <NUM> can detect the mover Rz orientation. Two other possible orientations (<FIG>) can also be detected with similar methods by reading the unique information from the <NUM>nd MRU <NUM> overlapping with effective stator coupling coil region <NUM>. It should be noted that the four <NUM>nd MRU <NUM> should be positioned such that, when the mover center <NUM> is positioned in the determining position (x0, y0) (which may otherwise be known as a sensing position), there is always at least one <NUM>nd MRU <NUM> overlapping with the coupling coil assembly <NUM> in the Z direction. Although in the above description the term mover center <NUM> has been used, generally, any suitable reference point <NUM> on the mover <NUM> may be used.

Generally, the detection procedure can be summarized in the following steps:.

<FIG> and <FIG> show another embodiment according to the disclosure. As shown in <FIG>, a mover <NUM> comprises one <NUM>nd MRU <NUM>. However, when the mover <NUM> is placed onto the stator <NUM>, it may be in one of the four possible Rz orientations: (a), (b), (c), and (d) in<FIG>, with small Rz angle ranges such as +/- <NUM> or +/-<NUM> degrees. In order to determine the absolute Rz orientation in which the mover <NUM> is in, the mover <NUM> can be driven such that its reference point <NUM> (such as but not being limited to its center) is moved sequentially to each of the four determining locations (XA, YA), (XB, YB), (XC, YC), (XD, YD) shown in <FIG>. The distance d between <NUM>nd MRU <NUM> and the reference point <NUM> is equal to the distance d between effective stator coupling coil region <NUM> center and any of the four determining locations. As a result, the <NUM>nd MRU <NUM> will overlap with effective stator coupling coil region <NUM> in the Z direction when the reference point <NUM> is located in one of the four determining locations. Accordingly, the Rz orientation of the mover <NUM> can be derived. For example, if the mover Rz orientation is the case of (b) shown in <FIG>, then, when the reference point <NUM> is at (XD, YD), the coupling coil assembly <NUM> will detect the presence of <NUM>nd MRU <NUM>, but not when the reference point <NUM> is at any of the other three determining positions. As mentioned above, although the mover center <NUM> is used as a reference point for defining the mover position in the XY plane, this is not essential. The reference point could be any other point on the mover <NUM>. Furthermore, it is not essential for the mover <NUM> to be driven to all four determining locations before <NUM>nd MRU <NUM> is identified; the <NUM>nd MRU <NUM> may be detected before the mover <NUM> has been driven to all four determining locations.

<FIG> shows another embodiment according to the disclosure. The mover <NUM> comprise one <NUM>nd MRU <NUM>; the stator <NUM> comprises four stator coupling coil assemblies 60A, 60B, 60C, 60D, each with a respective effective stator coupling coil region 63A, 63B, 63C, 63D. When the reference point <NUM> is positioned at a determining location (x0,y0), the <NUM>nd MRU <NUM> overlaps with one of the four effective stator coupling coil regions 63A, 63B, 63C, 63D. As a result, regardless of which Rz orientation range of <FIG> the mover <NUM> is in, its absolute Rz orientation can be detected. For example, when the mover <NUM> as shown in <FIG>, effective static coupling coil region 63A overlaps with <NUM>nd MRU <NUM> in the Z direction, and thus can detect the presence of <NUM>nd MRU <NUM>. However, none of the other three coupling coil assemblies 60B, 60C, 60D can detect the presence of <NUM>nd MRU <NUM>. Based on which coupling coil assembly can detect <NUM>nd MRU <NUM>, the absolute Rz orientation range of mover <NUM> can be determined.

<FIG> show another non-limiting embodiment according to the disclosure. The <NUM>st MRU comprises a plurality of magnet arrays (four magnet arrays 12A, 12B, 12C, 12D for the example embodiment in <FIG>). Each magnet array comprises a plurality of magnetization segments <NUM> (four magnetization segments <NUM> in each magnet array in <FIG>). For example, magnet array 12A comprises four magnetization segments 14A. As shown in <FIG>, each of magnetization segments 14AA, 14AB, 14AC, 14AD is linearly elongated in the X direction and each magnetization segment has a magnetization direction orthogonal to its elongation direction in the X direction. As shown in <FIG>, near the center of the <NUM>st MRU magnet assembly in the X and Y directions, there is a magnet-free space <NUM>. Due to the <NUM>-degree symmetric configuration of the magnet assembly (i.e. when the magnet assembly is rotated around the Z axis by <NUM> degrees, there is no difference in terms of magnetic field generation from the <NUM>st MRU), in the magnet-free space <NUM> the magnetic flux from the <NUM>st MRU magnet assembly is in the +Z or -Z directions. In some embodiments, a <NUM>nd MRU <NUM> can be located inside the magnet-free space <NUM> and the <NUM>nd MRU flux generation axial direction is preferably positioned orthogonal to the Z direction. As a result, the flux from the permanent magnet of the <NUM>st MRU does not saturate the magnetic core <NUM> of the <NUM>nd MRU <NUM> in the flux generation axial direction, and thus interference between the <NUM>st MRU and the bidirectional transfer of information and/or power between <NUM>nd MRU and the stator coupling coil assembly <NUM> is minimized.

In some embodiments, it may be advantageous to position the <NUM>nd MRU <NUM> such that the <NUM>nd MRU magnetic core axial dimension center <NUM> (shown in <FIG>) does not coincide with the center <NUM> of the magnet-free space <NUM> so that the offset in the X and/or Y directions between them can be used to detect the mover <NUM>'s absolute Rz orientation (e.g. in which of the four possible Rz orientations the mover <NUM> is in).

As shown in <FIG>, a <NUM>nd MRU <NUM> is placed beside a magnet array 12B of the <NUM>st MRU so as to minimize the effect of the leakage flux from the magnet array 12B on the functionality of the <NUM>nd MRU <NUM>. The <NUM>nd MRU flux generation axial direction <NUM> is generally parallel to the elongation direction of its adjacent magnetization segment 14BA. As shown in <FIG>, the magnetization direction of each magnetization segment 14B in 12B is orthogonal to its elongation direction (i.e. the Y direction); when the <NUM>nd MRU flux generation axial direction <NUM> is generally parallel to the Y direction, the leakage flux from the magnet array will penetrate into the magnetic core <NUM> in a direction orthogonal to the <NUM>nd MRU flux generation axial direction <NUM>, which minimizes the likelihood that the leakage flux will saturate the magnetic core <NUM> in the <NUM>nd MRU flux generation axial direction <NUM>. As a result, the effect on the flux generation of <NUM>nd MRU <NUM> is minimized. Generally, in some embodiments, the <NUM>nd MRU flux generation axial direction <NUM> is generally parallel to the elongation direction of its adjacent magnetization segment of the <NUM>st MRU, where the magnetization segment has a magnetization direction orthogonal to its elongation direction.

Since magnet array 12B has a finite extension in the Y direction, the leakage field from the magnet array 12B has a Y-component that is strongest near the two ends of the magnet array 12B in the Y direction, and weakest near the plane extending in the X and Z directions and passing through the Y dimension center of the magnetization segment 12B. In some embodiments, it is advantageous to position the <NUM>st MRU <NUM> and <NUM>nd MRU <NUM> such that the <NUM>nd MRU magnetic core axial dimension center <NUM> is sufficiently near to or coincides with the plane extending in the X and Z directions and passing through the Y dimension center of the magnetization segment 12B adjacent to the <NUM>nd MRU magnetic core, or such that the <NUM>nd MRU magnetic core axial dimension center <NUM> is sufficiently far from the two ends of the magnet array 12B in the Y direction, such that the leakage field from the magnet array has a minimal axial (Y-direction) component. Sufficiently far from the two ends of the magnet array 12B may be interpreted as a Y-distance between the magnetic core axial dimension center <NUM> and the ends of the magnet array 12B that is larger than about <NUM>/<NUM> of the Y-dimension of the magnet array 12B. In some embodiments, sufficiently far may be interpreted as meaning that a distance separating either end of magnet array 12B from magnetic core axial dimension center <NUM> is greater than a length of the <NUM>nd MRU magnetic core.

<FIG> shows a particular embodiment according to the disclosure. The stator <NUM> comprises a sensor <NUM> that is significantly larger in the XY plane than the stator coupling coil assembly <NUM>. During operation of the robotics system <NUM>, the mover <NUM> is identified according to any of the herein-described methods, e.g. by moving the mover <NUM> such that its <NUM>nd MRU <NUM> overlaps with an effective stator coil region <NUM> in the Z direction, and information from the <NUM>nd MRU <NUM> is transmitted to the controller <NUM> through the interaction between the <NUM>nd MRU <NUM> and the stator coupling coil assembly <NUM>, and this information is used to identify the mover <NUM> and optionally determine the mover <NUM>'s absolute orientation. After this transmission of information, the controller <NUM> continuously tracks the position of the <NUM>st MRU <NUM> of mover <NUM> by using sensor <NUM>, so that the identification of mover <NUM> is always known, even when mover <NUM>'s <NUM>nd MRU <NUM> is not positioned above an effective stator coil region <NUM>. In this embodiment, it is only necessary to perform the identification of mover <NUM> once, through the interaction between the <NUM>nd MRU <NUM> and the stator coupling coil assembly <NUM>.

<FIG> shows that, in some embodiments, it may be advantageous to control the Z direction separation <NUM> between the mover <NUM> and the work surface <NUM> in order to achieve the strongest coupling between the <NUM>nd MRU <NUM> and the stator coupling coil assembly <NUM>. In a particular embodiment, the Z direction separation <NUM> is generally minimal (e.g. about <NUM>) such that the mover <NUM> is considered to be in contact with the work surface <NUM>. In some embodiments, the Z direction separation <NUM> is greater than <NUM>, such that the mover <NUM> is levitating above the work surface <NUM>. One reason for having different optimal Z direction separations is due to the different materials that may exist between <NUM>nd MRU <NUM> and stator coupling coil assembly <NUM> (e.g. such as the material forming work surface <NUM>), and that may affect the coupling between <NUM>nd MRU <NUM> and stator coupling coil assembly <NUM> in different ways.

As show in <FIG>, the controller <NUM> can be used transmit currents <NUM> into the actuation coil assembly <NUM>, as well as one or more currents <NUM> into the stator coupling coil assembly <NUM>. In some embodiments, it may be advantageous to turn off currents <NUM> when performing mover identification through the coupling between stator coupling coil assembly <NUM> and <NUM>nd MRU <NUM>. This may minimize the disturbance caused by currents <NUM> in stator coupling coil assembly <NUM>, so that the coupling between the <NUM>nd MRU <NUM> and the stator coupling coil assembly <NUM> may be maximized strongest. Similarly, it may be advantageous to turn off currents <NUM> when driving currents <NUM> into stator actuating coil assembly <NUM>, in order to minimize the disturbance caused by currents <NUM> on the stator actuating coil assembly <NUM>, so that the mover <NUM> may move smoothly during operation.

<FIG>, <FIG> show a particular embodiment in which the mover <NUM> has a rectangular footprint in the XY plane (e.g. in the plane of the stator working surface <NUM>), and the <NUM>nd MRU <NUM> is positioned near one of the long edges of mover <NUM>. In this arrangement, the <NUM>nd MRU <NUM> can be positioned inside the effective stator coupling region <NUM> for all mover orientations. Conversely, if the <NUM>nd MRU <NUM> is placed near one of the short edges of mover <NUM>, then it may not be possible for the <NUM>nd MRU <NUM> to overlap with effective stator coupling region <NUM> without having mover <NUM> extending beyond the stator work surface <NUM>.

In some embodiments, the stator coupling assembly <NUM> is positioned such that the XY center point of the stator coupling assembly <NUM> is roughly aligned with the XY center point of the stator <NUM> in the Z direction. This arrangement may accommodate different positions of the <NUM>nd MRU <NUM> on mover <NUM>, such as placing <NUM>nd MRU <NUM> on the edge of the mover <NUM> or placing <NUM>nd MRU <NUM> in the center of mover <NUM>. With the stator coupling assembly <NUM> positioned roughly in the XY center of the stator <NUM>, it is possible to achieve strong coupling between <NUM>nd MRU <NUM> and stator coupling assembly <NUM> without making the mover <NUM> extend beyond the boundaries of the stator <NUM>.

In some embodiments, <NUM>nd MRU <NUM> may be incorporated into a workpiece <NUM> carried by mover <NUM>, as shown in <FIG>, so that the workpiece <NUM> can be uniquely identified, regardless of which mover <NUM> is carrying the workpiece <NUM>. In some embodiments, the mover <NUM> comprises a magnet-free region <NUM>, so that the <NUM>nd MRU <NUM> placed in the workpiece <NUM> may overlap with the opening in the Z direction, to assist with the coupling between <NUM>nd MRU <NUM> and stator coupling assembly <NUM>, as shown in <FIG>.

In some embodiments, a <NUM>rd MRU <NUM> is incorporated into the workpiece <NUM> carried by the mover <NUM>, as shown in <FIG>. The <NUM>rd MRU <NUM> interacts with a <NUM>nd stator coupling coil assembly <NUM> in a similar fashion as the <NUM>nd MRU <NUM> interacts with the stator coupling coil assembly <NUM> described earlier. However, the <NUM>rd MRU is not configured to interact with stator coupling coil assembly <NUM>, such that it is possible for the <NUM>nd stator coupling coil assembly <NUM> to interact only with the <NUM>rd MRU <NUM> in workpiece <NUM> without also interacting with the <NUM>nd MRU <NUM> in mover <NUM>. For example, <NUM>nd stator coupling coil assembly <NUM> and <NUM>rd MRU <NUM> may be configured to interact using one or more frequencies different than those used by stator coupling coil assembly <NUM> when interacting with <NUM>nd MRU <NUM>. Controller <NUM> may comprise a computer-readable medium having stored thereon computer program code which may be configured, when executed by one or more processors, to cause the one or more processors to perform any of the methods described herein. According to some embodiments, the computer program code, when read, may cause the one or more processors to perform the method now described in connection with <FIG> shows a flow diagram of a method of identifying a mover, as well as determining an orientation of the mover.

At block <NUM>, controller <NUM> activates actuation coil assembly <NUM>. For example, controller <NUM> may cause current to flow through actuation coil circuits <NUM>. At block <NUM>, by driving actuation coil circuits <NUM>, controller is able to move mover <NUM> over or on work surface <NUM>, through the interaction of the magnetic fields generated by actuation coil circuits <NUM> with the magnetic components of mover <NUM>. Mover <NUM> is moved to a sensing position, which may be a position in which a <NUM>nd MRU <NUM> of mover <NUM> overlaps effective stator coupling region <NUM>. At block <NUM>, identification information is read by controller <NUM>. For example, controller <NUM> may drive coupling coil circuits <NUM> so as initiate the transfer of data from <NUM>nd MRU <NUM> to stator coupling assembly <NUM>. Based on the identification information read by controller <NUM>, controller <NUM> may identify mover <NUM>.

Controller <NUM> may additionally determine the orientation of mover <NUM>. In particular, at block <NUM>, controller <NUM> determines whether it is possible based on the identification information obtained at block <NUM> to determine the orientation of mover <NUM>. For example, the identification information may include information identifying a position of the <NUM>nd MRU <NUM> on mover <NUM>. If it is possible to determine from the identification information the orientation of mover <NUM>, then at block <NUM> controller <NUM> determines the orientation of mover <NUM>. If it is not possible to determine from the identification information the orientation of mover <NUM>, then at block <NUM> controller <NUM> adjusts a position of the mover <NUM>. For example, through suitable driving of actuation coil circuits <NUM>, controller <NUM> may cause the mover <NUM> to be repositioned in the X and/or Y directions such that another <NUM>nd MRU <NUM> of mover <NUM> overlaps effective stator coupling region <NUM>. At block <NUM>, identification information is read by controller <NUM>. In particular, controller <NUM> drives coupling coil circuits <NUM> so as initiate the transfer of data from the other <NUM>nd MRU <NUM> to stator coupling assembly <NUM>. At block <NUM>, controller <NUM> determines whether it is possible based on the identification information of the other <NUM>nd MRU <NUM> to determine the orientation of mover <NUM>. The process repeats until controller <NUM> is able to determine the orientation of mover <NUM>.

According to some embodiments, the system may include more than one stator, with the stators positioned adjacent one another such a mover moving over or on the surface of a first one of the stators may be moved onto an adjacent one of the stators, such that the mover may then be moved over or on the adjacent stator.

According to some embodiments, the stator coupling coil circuits may be sized such that, for any given position of a mover on or over the work surface, at least a portion of the <NUM>nd MRU overlaps with at least a portion of the stator coupling coil circuits.

Throughout this description, it should be understood that a mover may carry one or more part(s), such as but not limited to more biological sample(s), device(s), one or more drugs possibly in suitable container(s), product(s) being assembled, raw part(s) or material(s), component(s), to meet the needs of a desired manufacturing purpose. Suitable tooling and/or material feeding mechanism may be installed or distributed along the sides of stators or over the stators from above, although these are not shown to avoid obscuring the description.

While a number of exemplary aspects and embodiments are discussed herein, those of skill in the art will recognize that the disclosure extends to any suitable modification, permutation, addition, and subcombination thereof falling into the scope of the appended claims. For example:.

The word "a" or "an" when used in conjunction with the term "comprising" or "including" in the claims and/or the specification may mean "one", but it is also consistent with the meaning of "one or more", "at least one", and "one or more than one" unless the content clearly dictates otherwise. Similarly, the word "another" may mean at least a second or more unless the content clearly dictates otherwise.

The terms "coupled", "coupling" or "connected" as used herein can have several different meanings depending on the context in which these terms are used. For example, the terms coupled, coupling, or connected can have a mechanical or electrical connotation. For example, as used herein, the terms coupled, coupling, or connected can indicate that two elements or devices are directly connected to one another or connected to one another through one or more intermediate elements or devices via an electrical element, electrical signal or a mechanical element depending on the particular context. The term "and/or" herein when used in association with a list of items means any one or more of the items comprising that list.

As used herein, a reference to "about" or "approximately" a number or to being "substantially" equal to a number means being within +/- <NUM>% of that number.

Claim 1:
A system comprising:
at least one magnetic mover including a first magnetic mover (<NUM>), wherein the first magnetic mover comprises at least one first magnetically responsive unit (<NUM>) and at least one second magnetically responsive unit (<NUM>);
a stator (<NUM>) defining a two-dimensional planar work surface and comprising:
an actuation coil assembly (<NUM>) comprising a plurality of actuation coils (<NUM>); and
at least one stator coupling coil (<NUM>) operable to interact with the at least one second magnetically responsive unit;
one or more sensors (<NUM>) for sensing a position of the first magnetic mover; and
one or more stator driving circuits for driving the actuation coil assembly to thereby move the first magnetic mover over the work surface,
wherein the at least one first magnetically responsive unit is positioned such that interaction of one or more magnetic fields emitted by the at least one first magnetically responsive unit with one or more magnetic fields generated by the actuation coil assembly when driven by the one or more stator driving circuits enables movement of the first magnetic mover in at least two degrees of freedom,
wherein, when a current is driven through the at least one stator coupling coil, the at least one stator coupling coil is configured to magnetically couple with the at least one second magnetically responsive unit for wirelessly transferring:
energy from the at least one stator coupling coil to the at least one second magnetically responsive unit; and
identification information from the at least one second magnetically responsive unit to the at least one stator coupling coil,
wherein the work surface separates the first magnetic mover from the at least one stator coupling coil, and
wherein the work surface separates the first magnetic mover from the actuation coil assembly.