Articulated arm coordinate measurement machine having a rotary switch

A rotary switch device such as that used on the probe end of an articulated arm coordinate measurement machine is provided. The rotary switch having a housing with an axis of rotation. A first actuator is coupled to the housing. A first switch is coupled to the first actuator, the first actuator being configured to selectively close the first switch. A first electrical circuit is provided. A first antenna circuit is electrically coupled the first switch to the first electrical circuit, wherein the first electrical circuit and first antenna circuit cooperate to modulate an operating field when the first switch is closed. A reader circuit is arranged fixed relative to the axis of rotation, the reader circuit including a transmitter configured to emit the operating field and a receiver configured to detect the modulated operating field.

BACKGROUND OF THE INVENTION

The present disclosure relates to metrology instruments that measure the three-dimensional coordinates of points on an object, and more particularly, to a metrology instrument having near field communications (NFC) capability to communicate with one or more external devices.

Metrology instruments, such as portable articulated arm coordinate measuring machines (AACMMs), laser trackers, laser scanners and triangulation scanners for example, have found widespread use in the manufacturing or production of parts where there is a need to rapidly and accurately verify the dimensions of the part during various stages of the manufacturing or production (e.g., machining). Portable metrology instruments represent a vast improvement over known stationary or fixed, cost-intensive and relatively difficult to use measurement installations, particularly in the amount of time it takes to perform dimensional measurements of relatively complex parts. In the instance of a portable AACMM, the user simply guides a probe along the surface of the part or object to be measured. The measurement data are then recorded and provided to the user. In some cases, the data are provided to the user in visual form, for example, three-dimensional (3-D) form on a computer screen. In other cases, the data are provided to the user in numeric form, for example when measuring the diameter of a hole, the text “Diameter=1.0034” is displayed on a computer screen.

An example of a prior art portable articulated arm CMM is disclosed in commonly assigned U.S. Pat. No. 5,402,582 ('582), which is incorporated herein by reference in its entirety. The '582 patent discloses a 3-D measuring system comprised of a manually-operated articulated arm CMM having a support base on one end and a measurement probe at the other end. Commonly assigned U.S. Pat. No. 5,611,147 ('147), which is incorporated herein by reference in its entirety, discloses a similar articulated arm CMM. In the '147 patent, the articulated arm CMM includes a number of features including an additional rotational axis at the probe end, thereby providing for an arm with either a two-two-two or a two-two-three axis configuration (the latter case being a seven axis arm).

Accordingly, while existing metrology instruments are suitable for their intended purposes the need for improvement remains, particularly in providing a method and apparatus for communicating between the metrology instrument and a device to allow the operator to control a metrology instrument, configure the metrology instrument, or change parameters on the metrology instrument.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with an embodiment, a rotary switch device is provided. The rotary switch including a housing have an axis of rotation. A first actuator is coupled to the housing. A first switch is coupled to the first actuator, the first actuator being configured to selectively close the first switch. A first electrical circuit is provided. A first antenna circuit is electrically coupled the first switch to the first electrical circuit, wherein the first electrical circuit and first antenna circuit cooperate to modulate an operating field when the first switch is closed. A reader circuit is arranged fixed relative to the axis of rotation, the reader circuit including a transmitter configured to emit the operating field and a receiver configured to detected the modulated operating field.

In accordance with another embodiment, a portable articulated arm coordinate measuring machine (AACMM) is provided. The AACMM includes a manually positionable articulated arm having opposed first and second ends, the arm including a plurality of connected arm segments, each of the arm segments including at least one position transducer for producing a position signal. An electronic processing system is electrically coupled to receive the position signals. A probe end is coupled to the first end, the probe end having a housing coupled to the first end to rotate about an axis. A measurement device is coupled to the housing and electrically coupled to the electronic processing system. A first actuator is coupled to the housing. A first switch is coupled to the first actuator, the first actuator being configured to selectively close the first switch. A first electric circuit is provided. A first antenna circuit is electrically coupled to the first switch to the first electric circuit, wherein the first near field communication circuit and first antenna circuit cooperate to modulate an operating field when the first switch is closed. A reader circuit is arranged fixed relative to the axis of rotation, the reader circuit including a transmitter configured to emit the operating field and a receiver configured to detect the modulated operating field.

In accordance with another embodiment of the invention, a method of conveying information with a portable articulated arm coordinate measuring machine (AACMM) is provided. The method including the steps of: providing a manually positionable articulated arm portion having opposed first and second ends, the arm portion including a plurality of connected arm segments, each of the arm segments including at least one position transducer for producing a position signal; providing a probe end coupled to the first end, the probe end having a housing arranged to rotate about an axis of rotation, the probe end further having a switch coupled to rotate with the housing, the switching being electrically coupled to a first electric circuit by an antenna circuit, the probe, the probe end further having a reader circuit fixedly arranged relative to the axis of rotation, wherein the electric circuit is arranged to move about the reader circuit; providing a measurement device coupled to the housing; providing an electronic processing system for receiving the position signals from the transducers and for determining a position of the measurement device; emitting an operating field with the reader circuit; closing the switch; modulating the operating field with the electric circuit and antenna circuit in response to the closing of the switch; transmitting a measurement signal to the electronic processing system in response to the reader circuit detecting the modulation of the operating field; and determining the three-dimensional coordinates of the measurement device with the electronic processing system in response to receiving the measurement signal.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention provides communicating between a 3D metrology instrument and a portable device, such as a phone, a tablet or another metrology instrument. Embodiments of the invention provide advantages in facilitating the configuration of settings, such as wireless communications parameters, in the metrology device. Embodiments of the invention provide advantages in allowing the remote control of the metrology device with a portable device. Embodiments of the invention provide still further advantages in allowing the wireless updating of boot load code for the metrology device by an operator. Further embodiments of the invention provide advantages in assignment of identification codes in position transducers through a near field communications circuit. Still further embodiments of the invention provide advantages in allowing service personnel to quickly determine configuration information of the metrology instrument. In still further embodiments of the invention advantages are gained in providing a near field communications device that functions as a powerless switch to eliminate mechanical components such as slip rings.

FIGS. 1-4illustrate exemplary metrology instruments, including an articulated arm coordinate measurement (AACMM) device100, a laser tracker device200, a time-of-flight (TOF) laser scanner device300and a triangulation scanning device400(collectively referred to herein as metrology devices) for example, according to various embodiments of the present invention. It should be appreciated that while embodiments herein may refer to specific metrology devices, the claimed invention should not be so limited. In other embodiments, the various embodiments may be used in other metrology devices, such as but not limited to laser line probes, total stations and theodolites for example.

Referring now toFIG. 1, an AACMM100according to various embodiments of the present invention, an articulated arm being one type of coordinate measuring machine. The AACMM100may be the same as that described in commonly owned U.S. Pat. No. 8,533,967 entitled “Coordinate Measurement Machine,” the contents of which are incorporated herein by reference. The exemplary AACMM100may comprise a six or seven axis articulated measurement device having a probe end401that includes a measurement probe housing102coupled to an arm portion104of the AACMM100at one end.

The arm portion104comprises a first arm segment106coupled to a second arm segment108by a rotational connection having a first grouping of bearing cartridges110(e.g., two bearing cartridges). A second grouping of bearing cartridges112(e.g., two bearing cartridges) couples the second arm segment108to the measurement probe housing102. A third grouping of bearing cartridges114(e.g., three bearing cartridges) couples the first arm segment106to a base116located at the other end of the arm portion104of the AACMM100. Each grouping of bearing cartridges110,112,114provides for multiple axes of articulated movement. Also, the probe end401may include a measurement probe housing102that comprises the shaft of the seventh axis portion of the AACMM100(e.g., a cartridge containing an encoder system that determines movement of the measurement device, for example a contact probe118, in the seventh axis of the AACMM100). In this embodiment, the probe end401may rotate about an axis extending through the center of measurement probe housing102. In use the base116is typically affixed to a work surface.

Each bearing cartridge within each bearing cartridge grouping110,112,114typically contains an encoder system (e.g., an optical angular encoder system). The encoder system (i.e., transducer) provides an indication of the position of the respective arm segments106,108and corresponding bearing cartridge groupings110,112,114that all together provide an indication of the position of the probe118with respect to the base116(and, thus, the position of the object being measured by the AACMM100in a certain frame of reference—for example a local or global frame of reference).

The probe118is detachably mounted to the measurement probe housing102, which is connected to bearing cartridge grouping112. A handle accessory126may be removable with respect to the measurement probe housing102by way of, for example, a quick-connect interface. In exemplary embodiments, the probe housing102houses a removable probe118, which is a contacting measurement device and may have different tips118that physically contact the object to be measured, including, but not limited to: ball, touch-sensitive, curved and extension type probes. In other embodiments, the measurement is performed, for example, by a non-contacting device such as a laser line probe (LLP). In an embodiment, the handle126is replaced with the LLP using the quick-connect interface. Other types of accessory devices may replace the removable handle126to provide additional functionality. Examples of such accessory devices include, but are not limited to, one or more illumination lights, a temperature sensor, a thermal scanner, a bar code scanner, a projector, a paint sprayer, a camera, a video camera, an audio recording system or the like, for example.

In accordance with an embodiment, the base116of the portable AACMM100contains or houses an electronic data processing system that includes a base processing system that processes the data from the various encoder systems within the AACMM100as well as data representing other arm parameters to support three-dimensional (3-D) positional calculations, and resident application software that allows for relatively complete metrology functions to be implemented within the AACMM100.

As will be discussed in more detail below, the electronic data processing system500in the base116may communicate with the encoder systems, sensors, and other peripheral hardware located away from the base116(e.g., a LLP that can be mounted to or within the removable handle126on the AACMM100). The electronics that support these peripheral hardware devices or features may be located in each of the bearing cartridge groupings110,112,114located within the portable AACMM100. As will be discussed in more detail herein, each of the angular encoders within the bearing cartridge groupings110,112,114includes a definable identification number that allows the electronic data processing system to determine which angular encoder transmitted a positional signal and also compensate for known calibration errors in the particular encoder. The 3-D positional calculations may be determined at least in part on positional signal that includes the angular encoder identification number.

An exemplary laser tracker system200illustrated inFIG. 2includes a laser tracker202, a retroreflector target204, an electronic data processing system500, and an optional auxiliary computer208. The laser tracker200may be similar to that described in commonly owned U.S. Provisional Application Ser. No. 61/842,572 filed on Jul. 3, 2013, the contents of which are incorporated herein by reference. It should be appreciated that while the electronic data processing system is illustrated external to the laser tracker200, this is for exemplary purposes and the electronic data processing system500may be arranged within the housing of the laser tracker200. An exemplary gimbaled beam-steering mechanism210of laser tracker200comprises a zenith carriage212mounted on an azimuth base214and rotated about an azimuth axis216. A payload218is mounted on the zenith carriage212and rotated about a zenith axis220. Zenith axis220and azimuth axis216intersect orthogonally, internally to tracker200, at gimbal point222, which is typically the origin for distance measurements.

A laser beam224virtually passes through the gimbal point222and is pointed orthogonal to zenith axis220. In other words, laser beam224lies in a plane approximately perpendicular to the zenith axis220and that passes through the azimuth axis216. Outgoing laser beam224is pointed in the desired direction by rotation of payload218about zenith axis220and by rotation of zenith carriage212about azimuth axis216. A zenith angular encoder226, internal to the tracker220, is attached to a zenith mechanical axis aligned to the zenith axis220. An azimuth angular encoder228, internal to the tracker, is attached to an azimuth mechanical axis aligned to the azimuth axis216. The zenith and azimuth angular encoders226,228measure the zenith and azimuth angles of rotation to relatively high accuracy. Outgoing laser beam224travels to the retroreflector target204, which might be, for example, a spherically mounted retroreflector (SMR).

By measuring the radial distance between gimbal point222and retroreflector204, the rotation angle about the zenith axis220, and the rotation angle about the azimuth axis216, the position of retroreflector204and thus the three-dimensional coordinates of the object being inspected is found by the electronic data processing system500within the local spherical coordinate system of the tracker.

Referring now toFIG. 3, an exemplary laser scanner300is shown in accordance with embodiment of the invention. The laser scanner300has a measuring head302and a base304. The laser scanner300may be similar to that described in commonly owned United States Patent Publication 2014/0078519 entitled “Laser Scanner,” the contents of which are incorporated by reference herein. The measuring head302is mounted on the base304such that the laser scanner300may be rotated about a vertical axis306. In one embodiment, the measuring head302includes a gimbal point308that is a center of rotation about a vertical axis306and a horizontal axis310. In an embodiment, the measuring head302has a rotary mirror312, which may be rotated about a horizontal axis310. The rotation about the vertical axis may be about the center of the base304. In an embodiment, the vertical (azimuth) axis306and the horizontal (zenith) axis310intersect at the gimbal point308, which may be an origin of a coordinate system.

The measuring head302is further provided with an electromagnetic radiation emitter, such as light emitter314for example, that emits an emitted light beam316. In one embodiment, the emitted light beam316is coherent light, such as a laser beam for example. The laser beam may have a wavelength range of approximately 300 to 1600 nanometers, for example 790 nanometers, 905 nanometers, 1550 nm, or less than 400 nanometers. It should be appreciated that other electromagnetic radiation beams having greater or smaller wavelengths may also be used. The emitted light beam316may be amplitude or intensity modulated, for example, with a sinusoidal waveform or with a rectangular waveform. The emitted light beam316is emitted by the light emitter314onto the rotary mirror312, where it is deflected to the environment. A reflected light beam318is reflected from the environment by an object320. The reflected or scattered light is intercepted by the rotary mirror312and directed into a light receiver322. The directions of the emitted light beam316and the reflected light beam318result from the angular positions of the rotary mirror312and the measuring head302about the axis306and axis310, respectively. These angular positions in turn depend on the rotary drives that cause rotations of the rotary mirror312and the measuring head302about the axis310and axis306, respectively. Each of the axes310,306include at least one angular transducer324,326for measuring angle. The angular transducer may be an angular encoder.

Coupled to the light emitter314and the light receiver322is an electronic data processing system500. The electronic data processing system328determines, for a multitude of surface points X, a corresponding number of distances d between the laser scanner300and surface points X on object320. The distance to a particular surface point X is determined based at least in part on the speed of light in air through which electromagnetic radiation propagates from the device to the surface point X. In one embodiment the phase shift between the laser scanner300and the surface point X is determined and evaluated to obtain a measured distance “d”. In another embodiment, the elapsed time between laser pulses is measured directly to determine a measured distance “d.”

The speed of light in air depends on the properties of the air such as the air temperature, barometric pressure, relative humidity, and concentration of carbon dioxide. Such air properties influence the index of refraction n of the air. The speed of light in air is equal to the speed of light in vacuum “c” divided by the index of refraction. In other words, cair=c/n. A laser scanner of the type discussed herein is based on the time-of-flight of the light in the air (the round-trip time for the light to travel from the device to the object and back to the device). A method of measuring distance based on the time-of-flight of light (or any type of electromagnetic radiation) depends on the speed of light in air.

In an embodiment, the scanning of the volume about the laser scanner300takes place by quickly rotating the rotary mirror312about axis310while slowly rotating the measuring head302about axis306, thereby moving the assembly in a spiral pattern. For such a scanning system, the gimbal point308defines the origin of the local stationary reference system. The base304rests in a local stationary frame of reference.

Referring now toFIG. 4, an embodiment of a triangulation scanner400is shown that includes a light source402and at least one camera404and an electronic data processing system500that determines the three dimensional coordinates of points on the surface410of an object408. The triangulation scanner may the same as that described in commonly owned U.S. patent application Ser. No. 14/139,021 filed on Dec. 23, 2013, the contents of which are incorporated herein by reference. A triangulation scanner400is different than a laser tracker200or a TOF laser scanner300in that the three-dimensional coordinates are determined based on triangulation principals related to the fixed geometric relationship between the light source402and the camera404rather than on the speed of light in air.

In general, there are two common types of triangulation scanners400. The first type, sometimes referred to as a laser line probe or laser line scanner, projects the line or a swept point of light onto the surface410. The reflected laser light is captured by the camera404and in some instances, the coordinates of points on the surface410may be determined. The second type, sometimes referred to as a structured light scanner, projects a two-dimensional pattern of light or multiple patterns of light onto the surface. The three-dimensional profile of the surface410affects the image of the pattern captured by the photosensitive array38within the camera404. Using information collected from one or more images of the pattern or patterns, the electronic data processing system406can in some instances determine a one-to-one correspondence between the pixels of the photosensitive array in camera404and the pattern of light emitted by the light source402. Using this one-to-one correspondence together with a baseline distance between the camera and the projector, triangulation principals are used by electronic data processing system500to determine the three-dimensional coordinates of points on the surface410. By moving the triangulation scanner400relative to the surface410, a point cloud may be created of the entire object408.

In general, there are two types of structured light patterns, a coded light pattern and an uncoded light pattern. As used herein the term coded light pattern refers to a pattern in which three dimensional coordinates of an illuminated surface of the object are based on single projected pattern and a single corresponding image. With a coded light pattern, there is a way of establishing a one-to-one correspondence between points on the projected pattern and points on the received image based on the pattern itself Because of this property, it is possible to obtain and register point cloud data while the projecting device is moving relative to the object. One type of coded light pattern contains a set of elements (e.g. geometric shapes) arranged in lines where at least three of the elements are non-collinear. Such pattern elements are recognizable because of their arrangement. In contrast, as used herein, the term uncoded structured light pattern refers to a pattern that does not allow 3D coordinates to be determined based on a single pattern. A series of uncoded light patterns may be projected and imaged sequentially, with the relationship between the sequence of obtained images used to establish a one-to-one correspondence among projected and imaged points. For this embodiment, the triangulation scanner400is arranged in fixed position relative to the object408until the one-to-one correspondence has been established.

It should be appreciated that the triangulation scanner400may use either coded or uncoded structured light patterns. The structured light pattern may include the patterns disclosed in the journal article “DLP-Based Structured Light 3D Imaging Technologies and Applications” by Jason Geng published in the Proceedings of SPIE, Vol. 7932, which is incorporated herein by reference.

Collectively, the metrology instruments such as the AACMM100, the laser tracker200, the TOF laser scanner300and the triangulation scanner400are referred to herein as metrology devices. It should be appreciated that these metrology instruments are exemplary and the claimed invention should not be so limited, as the systems and methods disclosed herein may be used with any metrology instrument configured to measure three-dimensional coordinates of an object.

FIG. 5is a block diagram of an embodiment of an electronic data processing system500utilized in metrology devices100,200,300,400in accordance with an embodiment. The electronic data processing system500includes a base processor board502for implementing the base processing system, a communications module526, a base power board506for providing power, and a base tilt board508. As will be discussed in more detail below, the communications module526may include one or more sub-modules, such as a near field communications circuit (NFC), a cellular teleconference circuit (including LTE, GSM, EDGE, UMTS, HSPA and 3GPP cellular network technologies), a Bluetooth® (IEEE 802.15.1 and its successors) circuit and a Wi-Fi (IEEE 802.11) circuit for example.

In embodiments, the metrology device100,200,300includes one or more encoders, and the electronic data processing system500for the metrology device is in communication with the aforementioned plurality of encoder systems via one or more electrical busses510. The metrology device100,200,300,400may further include an optical bus520in communication with the electronic data processing system500. It should be appreciated that the data processing system500may include additional components, such as connectors, terminals or circuits, for example, which are configured to adapt the incoming and outgoing signals to busses510,520. For the clarity purposes, not all of these components are shown inFIG. 5.

FIGS. 6A-6Bare block diagrams describing features of the electronic data processing system500of the metrology device100,200,300,400in accordance with an embodiment. In an embodiment, the electronic data processing system500is located internally within a housing of the metrology device and includes the base processor board502a base power board506, a communications module526, and a base tilt module508.

The base processor board502includes the various functional blocks illustrated therein. For example, a base processor function522is utilized to support the collection of measurement data from the metrology device and receives raw metrology data (e.g., encoder system or time of flight data), such as via electrical bus510. The memory function523stores programs and static metrology device configuration data. As will be discussed in detail below, in some embodiments the static configuration data may be stored in memory associated with an NFC module on the communications module526. The base processor board502may also include an external hardware option port functions for communicating with any external hardware devices or accessories such as but not limited to a graphical monitor or television via HDMI port, an audio device port, a USB 3.0 port and a flash memory (SD) card via port for example.

The base processor board502may also manage all the wired and wireless data communication with an external computing device. The base processor board502has the capability of communicating with an Ethernet network via a gigabit Ethernet function (e.g., using a clock synchronization standard such as Institute of Electrical and Electronics Engineers (IEEE) 1588), with a wireless local area network via communications module526. The communications module526may include a Bluetooth module528, a WiFi module530and a near field communications (NFC) module532. It should be appreciated that the communications module526may include other communications related circuits or modules and the modules described herein are exemplary and not intended to be limiting.

In the illustrated embodiment, the NFC module532is a dual-interface memory/tag device such as the M24SR series NFC tags manufactured by ST Microelectronics N.V. for example. A dual-interface memory device includes a wireless port that communicates with an external NFC reader, and a wired port that connects the device with another circuit, such as base processor board502. As will be discussed in more detail below, the use of a dual-interface memory device provides advantages allowing the NFC module532to interact with or control functionality of the base processing board502. In one embodiment, the NFC module532includes the boot load code, the executable code used by the processor522during operation initiation (initial power-on state of operation). By storing the boot load code in the memory of NFC module532, this executable code may be upgraded or replaced by the end-user using the NFC communications medium rather than involving service personnel.

In another embodiment, the NFC module532is a single port NFC tag, such as MIFARE Classic Series manufactured by NXP Semiconductors. With a single port tag, the module532is not electrically coupled to the base processor board502. In this embodiment, the NFC module532stores a set of device data regarding the metrology device, such as but not limited to: serial number, configuration, revision data or encoder identification data for example. This provides advantages in allowing the user or service personnel to quickly identify the metrology device. Further, this data may be used with a portable computing device to automatically associate the measurements made by the metrology device with the serial number of the instrument to allow tracing of the measurements to a particular instrument. It should be appreciated that in this embodiment, the NFC module532may be integrated onto the same board as the other modules as illustrated, or may be mounted separately. In one embodiment, the NFC module532is mounted to an adhesive label that is coupled to the outside of the metrology device.

Further, it should be appreciated that whileFIG. 6illustrates the communications module as having a single connection, this is for exemplary purposes and the connections from the sub-modules528,530,532to the base processor board502may include several connections, such as but not limited to a parallel to serial communications (PSC) function. The base processor board502also includes a connection to a universal serial bus (USB 3.0) device534.

The base processor board502transmits and collects raw measurement data (e.g., encoder system counts, temperature readings) for processing into measurement data without the need for any preprocessing. As will be discussed in more detail herein, the base processor502sends the processed data to an external computing device via a wired Ethernet interface, USB interface534or communications module526. In an embodiment, the base processor502also sends the raw measurement data to the external computing device.

Turning now to the communications module526, this module allows the base processor502to wirelessly transmit and receive signals from one or more computing devices, such as a portable computing device. These portable computing devices may include but is not limited to a cellular phone, a tablet computer, a wearable computer or a laptop for example. The external wearable device may be, for example, glasses having a display that shows the user the data/information from the metrology device as described herein. The wearable device may also be a watch with a display that shows the user data/information from the metrology device. The wearable device may further be an article such as a badge, ring, broach or pendant that displays information from the metrology device. It should be appreciated that these wearable devices may also indicate or display a subset of the data/information, for example, a ring may have an indicator that changes color based on a measurement parameter (e.g. the measurement was successfully acquired). The wearable device and other portable computing devices each have a processor and memory that is configured to execute computer instructions on the respective processor to perform the functions described herein.

The communications module526may transmit the angle and positional data received by the base processor and utilize it with applications executing on a portable computing device to provide a portable and autonomous metrology system that operates with the metrology device. Applications may be executed on the portable computing device to support functions such as, but not limited to: measurement of features, guidance and training graphics, remote diagnostics, temperature corrections, control of various operational features, connection to various networks, and display of measured objects.

The electronic data processing system500may also include a base power board506with an environmental recorder536for recording environmental data. The base power board506also provides power to the electronic data processing system500using an AC/DC converter538and a battery charger control540. The base power board506communicates with the base processor board502using inter-integrated circuit (I2C) serial single ended bus as well as via a DMA serial peripheral interface (DSPI). The base power board506is connected to a tilt sensor542via an input/output (I/O) expansion function544implemented in the base power board506.

Though shown as separate components, in other embodiments all or a subset of the components may be physically located in different locations and/or functions combined in different manners than that shown inFIG. 6. For example, in one embodiment, the base processor board502is shielded to reduce radio frequency (RF) interference and the communications module board526is disposed outside of the shielding to allow communication with external devices.

FIG. 7illustrates an embodiment of the NFC module532(sometimes colloquially referred to as an NFC tag or listening device) and an NFC reader550(sometimes colloquially referred to as a polling device). The term “near field communications” refers to a communications system that allows for a wireless communications between two devices over a short or close range, typically less than 5 inches (127 millimeters). NFC further provides advantages in that communications may be established and data exchanged between the NFC tag532and the reader550without the NFC tag532having a power source such as a battery. To provide the electrical power for operation of the NFC tag532, the reader emits a radio frequency (RF) field (the Operating Field). Once the NFC tag532is moved within the Operating Field, the NFC tag532and reader550are inductively coupled, causing current flow through an NFC tag antenna552. The generation of electrical current via inductive coupling provides the electrical power to operate the NFC tag532and establish communication between the tag and reader, such as through load modulation of the Operating Field by the NFC tag532. The modulation may be direct modulation, frequency-shift keying (FSK) modulation or phase modulation, for example. In one embodiment, the transmission frequency of the communication is 13.56 megahertz with a data rate of 106-424 kilobits per second.

In one embodiment, the NFC tag532includes a logic circuit554that may include one or more logical circuits for executing one or more functions or steps in response to a signal from the antenna552. It should be appreciated that logic circuit554may be any type of circuit (digital or analog) that is capable of performing one or more steps or functions in response to the signal from antenna552. In one embodiment, the logic circuit554may further be coupled to one or more memory devices556configured to store information that may be accessed by logic circuit554. NFC tags may be configured to read and write many times from memory556(read/write mode) or may be configured to write only once and read many times from memory556(card emulation mode). For example, where only static instrument configuration data is stored in memory556, the NFC tag may be configured in card emulation mode to transmit the configuration data in response to a reader device550being brought within range of the antenna552.

In addition to the circuits/components discussed above, in one embodiment the NFC tag532may also include a power rectifier/regulator circuit, a clock extractor circuit, and a modulator circuit. The Operating Field induces a small alternating current (AC) in the antenna when the reader is brought within range of the tag. The power rectifier and regulator converts the AC to stable DC and uses it to power the NFC tag, which immediately “wakes up” or initiates operation. The clock extractor separates the clock pulses from the Operating Field and uses the pulses to synchronize the logic, memory, and modulator sections of the NFC tag with the NFC reader. The logic circuit separates the 1's and 0's from the Operating Field and compares the data stream with its internal logic to determine what response, if any, is required. If the logic circuit determines that the data stream is valid, it accesses the memory section for stored data. The logic circuit encodes the data using the clock extractor pulses. The encoded data stream is input into the modulator section. The modulator mixes the data stream with the Operating Field by electronically adjusting the reflectivity of the antenna at the data stream rate. Electronically adjusting the antenna characteristics to reflect RF is referred to as backscatter. Backscatter is a commonly used modulation scheme for modulating data on to an RF carrier. In this method of modulation, the tag coil (load) is shunted depending on the bit sequence received. This in turn modulates the RF carrier amplitude. The NFC reader detects the changes in the modulated carrier and recovers the data.

In an embodiment, the NFC tag532is a dual-interface NFC tag, such as the aforementioned M24SR series NFC tags for example, having two ports, the antenna552for wireless communication and a wired port558. The wired port558may be coupled to transmit and receive signals from the processor522for example. In one embodiment, the memory556stores the boot load code for the processor522. As used herein the term “boot load code” or “boot loader code” is a set of computer program instructions that is loaded into the main memory523to initiate operation of the operating system on the processor522and the electronic data processing system500. The boot load code stored in NFC tag memory556may be a primary boot load code or a secondary boot load code.

It should be appreciated that while embodiments herein disclose the operation of the NFC tag532in a passive mode, meaning an initiator/reader device provides an Operating Field and the NFC tag responds by modulating the existing field, this is for exemplary purposes and the claimed invention should not be so limited. In other embodiments, the NFC tag532may operate in an active mode, meaning that the NFC tag532and the reader device550may each generate their own Operating Field. In an active mode, communication is performed by the NFC tag and reader device alternately generating an Operating Field. When one of the NFC tag and reader device is waiting for data, its Operating Field is deactivated. In an active mode of operation, both the NFC tag and the reader device may have its own power supply.

The reader device550is a portable or mobile computing device and may be a general computing device, such as a cellular (smart) phone or a tablet computer for example. The reader device550includes a processor560coupled to one or more memory modules562. The processor560may include one or more logical circuits for executing computer instructions. Coupled to the processor560is an NFC radio564. The NFC radio564includes a transmitter566that transmits an RF field (the Operating Field) that induces electric current in the NFC tag532. Where the NFC tag532operates in a read/write mode, the transmitter566may be configured to transmit signals, such as commands or data for example, to the NFC tag532.

The NFC radio564may further include a receiver568. The receiver568is configured to receive signals from, or detect load modulation of, the Operating Field by the NFC tag532and to transmit signals to the processor560. Further, while the transmitter566and receiver568are illustrated as separate circuits, this is for exemplary purposes and the claimed invention should not be so limited. In other embodiments, the transmitter566and receiver568may be integrated into a single module. The antennas being configured to transmit and receive signals in the 13.56 megahertz frequency.

Referring now toFIGS. 1 and 8-10, an embodiment is shown of the AACMM100cooperating with a mobile computing device, such as cellular phone602. The mobile computing device602may also be a smart pad, laptop computer, smart music player, or other type of device having a computer processor. It should be appreciated that while the illustrated embodiment is in reference to the AACMM100, these methods and processes may be similarly applied to other metrology devices, such as the laser tracker200, the TOF laser scanner300and the triangulation scanner400for example. In the exemplary embodiment, the cellular phone602includes a display606that presents a graphical user interface (GUI)608to the user. In one embodiment, the GUI608allows the user to view data, such as measured coordinate data for example, and interact with the cellular phone602. In one embodiment, the display606is a touch screen device that allows the user to input information and control the operation of the cellular phone602using their fingers. The cellular phone602further includes a processor610(FIG. 10) that is responsive to executable computer instructions and to perform functions or control methods, such as those illustrated inFIGS. 11-14 and 16for example. The cellular phone602may further include memory612, such as random access memory (RAM) or read-only memory (ROM) for example, for storing application code that is executed on the processor610and storing data, such as coordinate data for example. The cellular phone602further includes communications circuits, such as near field communications (ISO 14443) circuit614, Bluetooth (IEEE 802.15.1 or its successors) circuit550and WiFi (IEEE 802.11) circuit618for example. The communications circuits614,616,618are transceivers, meaning each is capable of transmitting and receiving signals. It should be appreciated that the cellular phone may include additional components and circuits, such as a cellular communications circuit, as is known in the art.

The cellular phone602may further include additional modules or engines620, which may be in the form of application software or “apps” that execute on processor610and may be stored in memory612. In one embodiment, a trigger module622is provided that cooperates with the NFC circuit550to activate one or more modules620when the NFC circuit550is brought within range of another NFC enabled device, such as AACMM100for example. In one embodiment, the trigger module622initiates the transfer of application program interface (API) code633from the metrology device100to the cellular phone602. In one embodiment, the API code633may be transmitted by an embedded web server631(FIG. 9) in the electronic data processing system500. In still another embodiment, the trigger module622initiates the downloading of an application or module (an “app”) from an online store or remote computing server when the desired module is not already installed on the device. The downloaded module then cooperates with the API code633to control one or more aspects of the metrology device. This provides advantages in that the size of the downloaded module may be reduced since the API's are stored on the metrology device. The downloaded module could include functionality such as controlling the 3D measuring instrument, collecting data from measurements made by the 3D measuring instruments, and displaying the results of data obtained from the metrology device.

The API code may be specific to the particular metrology device (such as AACMM100) and specify for the cellular phone602how the components or modules620interact with each other and the metrology device. It should be appreciated that the API code for an AACMM100may be different than that for a laser tracker200. In one embodiment, the API code specifies a set of functions or routines that accomplish a specific task or are allowed to interact with a specific software component. For example, there may be calls to functions or routines, such as but not limited to: connecting with the metrology device, disconnecting from the metrology device, acquiring a measurement, capturing a point cloud, initiating a compensation process, and acquiring an image for example.

While embodiments herein describe the transfer of API code from the metrology device to the cellular phone602when the NFC communication is established, this is for exemplary purposes and the claimed invention should not be so limited. In other embodiments, the API code may be transferred from the metrology device as needed, such as when a user executes an application module for example. In still other embodiments, the API code is transferred by the web server631once a WiFi connection is established between the metrology device and the cellular phone602.

In still other embodiments, the API code is stored in a remote computer server. The remote computer server may be arranged on the local area network or in a distributed/cloud computer network. A computer network may include a wireless network, a hardwire network or a cellular telecommunications network. It should be appreciated that the remote computer server may be comprised of a plurality computers in a distributed computing configuration. Where the API code is stored on a remote computer server, advantages may be gained by allowing for updating of the API code without having to transfer to each individual instrument. Further, API code may be stored/acquired based on the serial number of the metrology device. This provides advantages in allowing the API code to reflect changes in the manufacturing builds be organized efficiently. Further, by establishing communication with the remote computer server, other computing functions such as processing the three-dimensional coordinate data may be performed on the remote computer server.

The module620may also include a communications module624that establishes communications with the AACMM100using Bluetooth circuit618or WiFi circuit618(e.g. IEEE 802.11) for example. With a Bluetooth circuit618, the communications module624establishes communication directly with the portable computing device. A WiFi circuit618on the other hand will communicate with the portable computing device via an access point that connects the WiFi circuit618to a local area network. It should be appreciated that the portable computing device may incorporate an access point that allows the transmission of signals directly to the portable computing device via the WiFi circuit618. The modules620may also include a parameters module626, which allow the operator to change settings and parameters, such as encoder parameters within the electronic data processing system210of AACMM100. For example, the parameters module626may allow the changing of the WiFi settings (e.g. power levels, approved networks, service set identifier or SSID). It may also include instrument parameters related with the characteristics of the individual instrument—for example, kinematic model parameters that might be distances, angles, offsets, and so forth.

The module620may further include a control or measurement module628. The measurement module628allows the user to issue commands, such as indicating the type of measurement being performed to the AACMM100. In one embodiment, the measurement module628may receive an inspection plan, meaning a series of measurements to be performed, and present the measurements to the user in the order defined by the inspection plan. In one embodiment, an NFC circuit or tag532is either attached to the object being inspected or its accompanying documentation. The cellular phone602retrieves the inspection plan by placing the NFC module550into proximity of the object NFC tag. The NFC tag is powered by the Operating Field generated by the NFC circuit550and the inspection plan is transmitted to the cellular phone602. Finally, in the exemplary embodiment, the module620may include a calibration module630that provides instructions to the user on carrying out calibration steps for the AACMM100. The calibration module630may also perform calculations to process measurement results obtained from the calibration procedure.

In the exemplary embodiment, the metrology device100,200,300, or400may include on the instrument a visual indicator of NFC capability. For example, in an AACMM100, the visual indicator may be provided on an area604of the base116. In one embodiment, the NFC module532or its antenna552is located proximate the area604. To couple the portable computing device602to communicate with the AACMM100, the device602is brought in proximity (e.g. less than 5 inches) to the area604. When within range, the Operating Field generated by the NFC circuit550induces current within the NFC module532to power the NFC module532via inductive coupling. Once powered the NFC module532transmits a signal to the device602causing the trigger module622to initiate operation of one or more modules within the module620.

Once the NFC module550and the NFC circuit532establish communication, this may allow for a series of automated or partially automated functions to occur that facilitate the operation of the metrology device by the user. In the embodiment ofFIG. 11, a method700is provided that allows the establishment of communications between the portable computing device602and the AACMM100. The method700starts in block702where the user places the device602in proximity to the area604. The Operating Field created by the NFC circuit550induces a current in the NFC module532in block704, and in response a signal is transmitted to the NFC module550in block706, such as by modulation of the Operating Field. The receipt of the signal by the NFC module550in block708activates the trigger module622, which executes one or more modules620, such as the communications module624for example. As discussed above, the metrology device may also transmit API code to the device602.

In block710, the communication module624transmits signals to the NFC module532that include parameters to configure in block712communication between the device602and the metrology device (e.g. AACMM100) using a communications protocol, such as cellular telecommunications (e.g. LTE), Bluetooth or WiFi, for example, that allows the user to maintain communication between the device602and the metrology device at greater distances than is allowed by NFC. This provides advantages in allowing the user to move the device602while maintaining communication with the metrology device during the measurement process. Once the communication channels are established, the method700proceeds to block714where a signal may be transmitted to the metrology device, such as with measurement module628for example. A function is executed by the metrology device, such as acquire a coordinate data on an object in block716. The data is then transmitted to the device602in block718, such as to display the coordinate data on the display506for example.

It should be appreciated that the ability to establish communications in a simple manner between the device602and the metrology device provides advantages in the set up and operation of the metrology device. For example, where a local area network or wireless network is not available (e.g. a construction site), the establishment of communications via the NFC tag could be used to initiate a process within the cellular phone to establish an ad-hoc WiFi network (e.g. a hotspot) for communication between different metrology devices. Further, this ad-hoc network could use the cellular data telecommunications capability (e.g. LTE) of the cellular phone to transmit and receive data from a remote computer server.

In still further embodiments, the establishment of communications via the NFC tag could be used to coordinate measurements performed by multiple metrology devices. In this embodiment, the device is brought into proximity with each of the metrology devices and establishes communications with each. The device is then used to control the collection of instruments and collect data as needed. In one embodiment, the device is used to determine one or more measurements that utilize data from a plurality of metrology devices.

In still further embodiments, the establishment of communications via the NFC tag could be extended to establish communications with other peripheral equipment and devices, such as robotic device or assembly line machinery for example. In this embodiment, having established communications with the metrology device and the peripheral equipment could quickly and simply establish control and coordination of the operation.

In another embodiment shown inFIG. 12, a method720provides for the updating of parameters in the metrology device. In this embodiment, communication between the device602and the metrology device is established in blocks702,704,706,708as described herein above. In this embodiment, the trigger module622may initiate activation of the parameters module622. With the parameters module622operating on the device602, the user selects or enters the data parameters that need to be updated or changed on the metrology device in block722. The updated parameters are transmitted to the metrology device in block724. In one embodiment, the parameters are stored in the metrology device memory523in block726, such as in the NFC module532or in memory556for example. It should be appreciated that the transfer of parameters from the device602to the metrology device may be performed through the NFC communications medium, the Bluetooth communications medium or the WiFi communications medium. For example, a Wifi parameter may include the set-service identifier (SSID) of the wireless network, or the acceptable power output of the WiFi radio. Further, it should be appreciated that when the parameters module622is executed, the current settings of metrology device may be transmitted to the device602for review by the user prior to updating or changing of the settings. It should be appreciated that this provides advantages in allowing the metrology device to be quickly configured to comply local regulatory requirements. For example different jurisdictions have different output power limitations for wireless communications circuits (e.g. WiFi). Typically manufacturers create different model instruments that are preconfigured to comply with the different regulatory requirements. Embodiments of the present invention provide advantages in allowing the metrology device to be quickly configured, either prior to shipping from the manufacturer or at the location of use via a mobile general purpose computing device, such as a cellular phone.

Referring now toFIG. 13, another embodiment is shown for updating the boot load code that initiates operation of the metrology device. In this embodiment, a method730starts in block732with the metrology device in the powered off state of operation. The method730then proceeds to block734where the NFC module532is activated via inductive coupling as described herein above. When the NFC module532is powered, a signal is transmitted to the NFC circuit550in block736. The trigger module622initiates the execution of an update module on the device602in block738. The update module transmits to the NFC module532the updated boot load code in block740and the new boot load code is stored in memory556in block742. It should be appreciated that in this embodiment, the boot load code is stored in the NFC module532since the base processor board502is unpowered. Therefore, the executable code used by the processor522during the initiation or boot process is obtained from the NFC module532when the metrology device is powered on in block744and booted in block746. In one embodiment, the memory used in the NFC module532is but not limited to universal serial bus, 1-wire, inter-integrated circuit (I2C) or a serial peripheral interface (SPI) types of memory. In one embodiment, the boot load code is a first level code used to initiate or boot the processor522. In another embodiment, the boot load code is a secondary level code that is executed by the processor522after initial activation.

Referring now toFIG. 14, another embodiment is shown of a method748for operating the metrology device with the device602in accordance with an inspection plan. Method748starts in block750by storing an inspection plan on an object NFC tag. As used herein, the term “inspection plan” refers to a set or series of measurements that are performed on the object, such as to determine if the object was manufactured within the desired specifications for example. The object NFC tag may be directly coupled to the object (e.g. an adhesive label) or may be coupled to an associated item, such as a bin, a tote, a box, an engineering drawing or other documentation for example. The method748then proceeds to block752where the object NFC tag is activated by the device602. The method748then transmits the inspection plan to the device602in block754. The user then moves the device602in proximity to metrology device and activates the NFC module532in block486and communication between the device602and the metrology device is established in block758as described herein above. The device602then displays on the display606instructions on a measurement, or a series of measurements for the object that the user is to acquire using the metrology device in block760. In one embodiment, the instructions are displayed sequentially in the order they are to be performed. In another embodiment, the instructions are displayed as a group or list and the user selects the measurements prior to performing the measurement with the metrology device.

The user then performs the measurement (e.g. flatness of a surface, diameter of a hole or surface, etc.) or determines three-dimensional coordinate data in block762. In query block764, it is determined whether there are any additional measurements to be performed. If query block764returns a positive, the method748loops back to block760and the next measurement in the inspection plan is displayed and acquired. If query block764returns a negative, the method748proceeds to block766where the acquired data is stored. In some embodiments, the device602may download from the web server631of the metrology device additional APIs required to complete the inspection plan.

It should be appreciated that components within the metrology device may incorporate NFC tags. For example, as shown inFIGS. 15-16, in an embodiment, the metrology device is an AACMM100and each of the bearing cartridge groupings110,112,114includes one or more NFC tags770. As discussed above, each of the bearing cartridge groupings110,112,114includes one or more rotary encoders that measure the amount of rotation of an axis of a bearing cartridge. These encoders include device data, such as a unique identification number or address relative to the other encoders in the AACMM. This identification number is transmitted with the rotary data to the electronic data processing system210. In this way, the electronic data processing system210may determine which encoder transmitted the positional signal and the 3-D positional calculations may be determined. Further, during the manufacturing process, each of the encoders is measured and calibrated. This calibration data may be utilized by the AACMM100in compensating the 3D measurements. Further, by providing an NFC tag770, the calibration data may be stored with the encoder and therefore more reliably tracked and applied by the AACMM100.

Typically, in prior art systems, the identification number was assigned to an encoder using a manual dual in-line package (DIP) switch. As a result, when an encoder is replaced, the installer needs to determine identification number or address of the encoder and manually assign the new encoder with the same identification number. In the exemplary embodiment, the identification number for the encoder is stored in the NFC tag770. Thus, by placing the device602adjacent the NFC circuit500, the operator may determine the identification number of the encoder. Further, in one embodiment, the NFC circuit770is a read-write type of NFC circuit. This also provides advantages in allowing the operator to change the identification number of the encoder.

Referring now toFIG. 16, a method772for assigning an identification-number/address to an encoder. The method772starts with activating the NFC tag770with the device602in block774. The NFC tag500then transmits a signal to the device602in block776which causes trigger module622to execute an application module on the device602for communicating with an NFC tag in block778. The user selects or enters an encoder identification number using the application module in block780. The new identification number is transmitted to the NFC tag770in block782. The new identification number is stored in the NFC tag770memory in block784where it may be accessed by the encoder during operation of the AACMM100.

Another exemplary embodiment is shown inFIG. 17A and 17Bof an NFC tag being used with a metrology device, such as AACMM100, for communicating between two components that move relative to each other. In this embodiment, the AACMM100is a six-axis coordinate measurement machine. In a six-axis AACMM, the bearing cartridge812only rotates about a single axis800and there is no rotation of the probe end401about the centerline802. However, in some embodiments, the probe housing814includes a grip portion804that freely rotates about the centerline802. It should be appreciated that this arrangement facilitates the user holding the probe end401in a comfortable position during operation. It also facilitates redirecting a beam of light from a line scanner attached to the end of the articulated arm, should one be present. Mounted on the grip portion804are one or more actuators806,808. These actuators allow the operator to activate different functions of the metrology device, such as taking a measurement for example.

In one embodiment, each actuator806,808includes an NFC tag532A,532B coupled to a switch810A,810B. The switches810A,810B are arranged as part of the antenna circuit552A,552B of each NFC tag532A,532B. An NFC reader550is arranged in the probe housing102adjacent the actuators806,808, such that NFC reader550remains stationary relative to the grip portion804. In other words, the grip portion, and therefore the actuators806,808, rotate about the NFC Reader550. The switches810A,810B are configured to be in a “normally open” position, meaning that the switches810A,810B form an open circuit unless the respective actuator806,808is depressed or actuated by the operator. Thus, when the actuators806,808are actuated, the switches810A,810B are closed allowing the respective antenna circuits552A,552B to be formed.

The NFC reader550continuously emits an Operating Field during operation. When the actuators806,808are not actuated by the operator, the open switches810A,810B prevent inductive coupling. Thus, the NFC tags532A,532B are not powered and no signal is transmitted by the NFC tags532A,532B. Once an actuator806,808is actuated, the antenna circuit for the respective NFC tag is closed. The NFC tag then modulates the Operating Field to signal the NFC reader550that the actuator has been actuated. As a result, the NFC reader550may transmit a signal to the electronic data processing system206indicating that the respective actuator806,808has be actuated. It should be appreciated that the coupling of the NFC tags to a movable body member has advantages in allowing signals indicating the activation of an actuator on the movable body member to be transmitted wirelessly without the need for expensive and complicated slip rings. Thus the costs of the AACMM100may be reduced while also improving reliability.

It should be appreciated that while embodiments herein describe communication between the AACMM100and the portable computing device602, this is for exemplary purposes and the claimed invention should not be so limited. In another embodiment, the NFC module532may be used to couple the AACMM with a portable accessory, such as but not limited to a laser line probe, a laser scanner, or a retroreflector for example. The NFC module532may also be used to establish communication with accessories coupled to the probe end401for example. The communication between the AACMM100and the accessories via the NFC communications medium may allow the AACMM100to set parameters or settings within the accessory, or may synchronize the accessory clock with that of the AACMM for example.

It should be appreciated that while embodiments described herein make reference to an AACMM, the claimed invention should not be so limited. In other embodiments, the NFC circuits may be used with other metrology instructions, such as but not limited to laser trackers, laser scanners and laser line probes for example. In one embodiment, an NFC circuit may be implemented in a laser tracker and a retroreflector to allow the serial number of the retroreflector to be automatically associated with data acquired by the laser tracker for example.

In an embodiment, a rotary switch device is provided. The rotary switch including a housing have an axis of rotation. A first actuator is coupled to the housing. A first switch is coupled to the first actuator, the first actuator being configured to selectively close the first switch. A first electrical circuit is provided. A first antenna circuit is electrically coupled the first switch to the first electrical circuit, wherein the first electrical circuit and first antenna circuit cooperate to modulate an operating field when the first switch is closed. A reader circuit is arranged fixed relative to the axis of rotation, the reader circuit including a transmitter configured to emit the operating field and a receiver configured to detect the modulated operating field.

In an embodiment, the first electric circuit and the first antenna circuit are inductively coupled when the first switch is in the closed position. The reader circuit may be configured to transmit a signal in response to detecting modulation of the operating field. In an embodiment, the rotary switch may further comprise a second actuator coupled to the housing. A second switch may be coupled to the second actuator, the second actuator being configured to selectively close the second switch. A second electric circuit is provided having a second logic circuit. A second antenna circuit is electrically coupled the second switch to the second electric circuit, wherein the second electric circuit and second antenna circuit cooperate to modulate the operating field when the second switch is closed.

In another embodiment, a portable articulated arm coordinate measuring machine (AACMM), is provided. The AACMM includes a manually positionable articulated arm having opposed first and second ends, the arm including a plurality of connected arm segments, each of the arm segments including at least one position transducer for producing a position signal. An electronic processing system is electrically coupled to receive the position signals. A probe end is coupled to the first end, the probe end having a housing coupled to the first end to rotate about an axis. A measurement device is coupled to the housing and electrically coupled to the electronic processing system. A first actuator is coupled to the housing. A first switch is coupled to the first actuator, the first actuator being configured to selectively close the first switch. A first electric circuit is provided. A first antenna circuit is electrically coupled to the first switch to the first electric circuit, wherein the first near field communication circuit and first antenna circuit cooperate to modulate an operating field when the first switch is closed. A reader circuit is arranged fixed relative to the axis of rotation, the reader circuit including a transmitter configured to emit the operating field and a receiver configured to detect the modulated operating field.

In an embodiment, the first switch is a normally open type switch. The first electric circuit and the first antenna circuit may be inductively coupled when the first switch is in the closed position. The reader circuit may be configured to transmit a measurement signal to the electronic processing system in response to detecting modulation of the operating field. In an embodiment, the AACMM further comprises a second actuator coupled to the housing. A second switch is coupled to the second actuator, the second actuator being configured to selectively close the second switch. A second electric circuit is provided. A second antenna circuit is electrically coupled to the second switch to the second electric circuit, wherein the second electric circuit and second antenna circuit cooperate to modulate the operating field when the second switch is closed. In another embodiment, the measurement signal is transmitted from the reader circuit to the electronic processing system, the electronic processing system providing data corresponding to a position of the measurement device in response to the measurement signal.

In another embodiment, a method of conveying information with a portable articulated arm coordinate measuring machine (AACMM) is provided. The method including the steps of: providing a manually positionable articulated arm portion having opposed first and second ends, the arm portion including a plurality of connected arm segments, each of the arm segments including at least one position transducer for producing a position signal; providing a probe end coupled to the first end, the probe end having a housing arranged to rotate about an axis of rotation, the probe end further having a switch coupled to rotate with the housing, the switching being electrically coupled to a first electric circuit by an antenna circuit, the probe, the probe end further having a reader circuit fixedly arranged relative to the axis of rotation, wherein the electric circuit is arranged to move about the reader circuit; providing a measurement device coupled to the housing; providing an electronic processing system for receiving the position signals from the transducers and for determining a position of the measurement device; emitting an operating field with the reader circuit; closing the switch; modulating the operating field with the electric circuit and antenna circuit in response to the closing of the switch; transmitting a measurement signal to the electronic processing system in response to the reader circuit detecting the modulation of the operating field; and determining the three-dimensional coordinates of the measurement device with the electronic processing system in response to receiving the measurement signal.

In an embodiment, the method may further include inductively coupling the reader circuit with the antenna circuit and electric circuit in response to the switch being closed. In an embodiment, the method may further include providing a second switch coupled to the housing. A second electric circuit is disposed to rotate about the reader circuit. A second antenna circuit is electrically coupled the second switch and to the second electric circuit, wherein the second electric circuit and second antenna circuit cooperate to modulate the operating field when the second switch is closed.

In an embodiment, the method further includes inductively coupling the reader circuit, the second antenna circuit and the second electric circuit in response to the second switch being closed. In an embodiment, the method further includes transmitting a second measurement signal to the electronic circuit in response to the switch being closed.

Technical effects and benefits include providing a contactless switch without the use of slip rings for a device having a housing with switches that rotates about an axis such as on the probe end of an articulated arm coordinate measurement machine. The technical effects and benefits further include the improved reliability and a lower cost switch.

While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.