The subject matter disclosed herein relates to coordinate measurement devices and systems, and particularly to stable mobile platforms for use therewith.
The present disclosure relates to coordinate measuring devices and mobile platforms thereof. One set of coordinate measurement devices belongs to a class of instruments that measure three-dimensional (3D) coordinates of a target point by sending a beam of light to the point. The beam of light may impinge directly on the point or on a retroreflector target in contact with the point. In either case, the instrument determines the coordinates of the target point by measuring a distance and two angles to the target. The distance is measured with a distance-measuring device such as an absolute distance meter or an interferometer. The angles are measured with an angle-measuring device such as an angular encoder. The beam may be steered with a gimbaled mechanism, a galvanometer mechanism, or other mechanism.
A laser tracker is a particular type of coordinate-measuring device that tracks a retroreflector target with one or more beams emitted therefrom, which may include light from a laser or non-laser light source. Coordinate-measuring devices closely related to laser trackers are time-of-flight (TOF) scanners and a total station. A TOF scanner steps one or more beams of light to points on a surface. The TOF scanner picks up light reflected from the surface and, in response, determines a distance and two angles to each surface point. A total station is a 3D measuring device most often used in surveying applications. It may be used to measure the coordinates of a diffusely scattering target or a retroreflective target. Hereinafter, the term laser tracker is used in a broad sense to include, but is not limited to, laser scanners and total stations and to include dimensional measuring devices that emit laser or non-laser light.
In many cases, a laser tracker sends a beam of light to a retroreflector target. A common type of retroreflector target is a spherically mounted retroreflector (SMR), which comprises a cube-corner retroreflector embedded within a metal sphere. The cube-corner retroreflector comprises three mutually perpendicular mirrors. The vertex, which is the common point of intersection of the three mirrors, is located at the center of the sphere. Because of this placement of the cube corner within the sphere, the perpendicular distance from the vertex to any surface of the SMR rests remains constant, even as the SMR is rotated. Consequently, the laser tracker can measure the 3D coordinates of a surface by following the position of an SMR as it is moved over the surface. Stating this another way, the laser tracker needs to measure only three degrees of freedom (one radial distance and two angles) to fully characterize the 3D coordinates of a surface.
One type of laser tracker contains only an interferometer (IFM) without an absolute distance meter (ADM). If an object blocks the path of the laser beam from one of these trackers, the IFM loses its distance reference. The operator must then track the retroreflector to a known location to reset to a reference distance before continuing the measurement. A way around this limitation is to put an ADM in the tracker. The ADM can measure distance in a point-and-shoot manner, as described in more detail below. Some laser trackers contain only an ADM without an interferometer.
A gimbal mechanism within the laser tracker may be used to direct a laser beam from the tracker to the SMR. Part of the light retroreflected by the SMR enters the laser tracker and passes on to a position detector. A control system within the laser tracker uses position of the light on the position detector to adjust the rotation angles of the mechanical axes of the laser tracker to keep the beam of light centered on the SMR. In this way, the tracker is able to follow (track) a moving SMR.
Angle measuring devices such as angular encoders are attached to the mechanical axes of the tracker. The one distance measurement and two angle measurements of the laser tracker are sufficient to completely specify a three-dimensional location of the SMR. In addition, several laser trackers are available or have been proposed for measuring six degrees-of-freedom (six-DOF), rather than the ordinary three degrees-of-freedom.
Although laser trackers are generally suitable for their intended purpose, some limitations still exist in tracker complexity, maintenance, resistance to shock, and identification of target objects. Further, at times, it may be beneficial and/or required to move a laser tracker or other coordinate measurement device. When moving a coordinate measurement device, the coordinate system may require resetting or recalibration, and having a system for efficiently moving and maintaining stability of such coordinate measurement devices may be helpful. What is needed is a laser tracker having features to overcome these limitations and provide other features and/or functionality thereto.
According to aspects of the present disclosure, platforms configured to support coordinate measurement devices are provided. The platforms include a base plate defining a stable mobile platform, at least one movement device configured to enable movement of the stable mobile platform, at least one stabilizing actuator configured to deploy a stabilizer to engage with a surface, the at least one stabilizing actuator moveable between a deployed state in which the stabilizer contacts a surface and a mobile state in which the at least one movement device contacts the surface, and a platform controller configured to drive movement of the stable mobile platform by controlling operation of the at least one movement device when the at least one stabilizing actuator is in the mobile state.
In addition to one or more of the features described above, or as an alternative, further embodiments of the platforms for coordinate measurement devices may include a coordinate measurement device mounted to the base plate.
In addition to one or more of the features described above, or as an alternative, further embodiments of the platforms for coordinate measurement devices may include that the base plate is triangular in shape.
In addition to one or more of the features described above, or as an alternative, further embodiments of the platforms for coordinate measurement devices may include three stabilizing actuators, wherein one stabilizing actuator is positioned at each corner of the triangular shape on the base plate.
In addition to one or more of the features described above, or as an alternative, further embodiments of the platforms for coordinate measurement devices may include at least one sensor configured to track a position of the stable mobile platform within an environment, wherein the at least one sensor is configured in communication with the platform controller.
In addition to one or more of the features described above, or as an alternative, further embodiments of the platforms for coordinate measurement devices may include that the at least one sensor is a proximity sensor.
In addition to one or more of the features described above, or as an alternative, further embodiments of the platforms for coordinate measurement devices may include that the at least one sensor is an inertial movement unit.
In addition to one or more of the features described above, or as an alternative, further embodiments of the platforms for coordinate measurement devices may include a support plate arranged proximate to the base plate and connected to the base plate by at least one plate connector to form a stable mobile platform.
In addition to one or more of the features described above, or as an alternative, further embodiments of the platforms for coordinate measurement devices may include at least one sensor configured to track a position of the stable mobile platform within an environment, wherein the at least one sensor is configured in communication with the platform controller, wherein the at least one sensor is mounted to the support plate.
In addition to one or more of the features described above, or as an alternative, further embodiments of the platforms for coordinate measurement devices may include that the at least one movement device is an omni-directional wheel.
In addition to one or more of the features described above, or as an alternative, further embodiments of the platforms for coordinate measurement devices may include that the at least one movement device is a Mecanum wheel.
In addition to one or more of the features described above, or as an alternative, further embodiments of the platforms for coordinate measurement devices may include that the at least one movement device includes a roller element and a drive element.
In addition to one or more of the features described above, or as an alternative, further embodiments of the platforms for coordinate measurement devices may include that the drive element is configured in communication with the platform controller.
In addition to one or more of the features described above, or as an alternative, further embodiments of the platforms for coordinate measurement devices may include that the at least one stabilizing actuator is one of a hydraulic actuator, an electromechanical actuator, and a linear actuator.
According to some embodiments, systems are provided that include a platform configured to support a coordinate measurement device. The platform includes a base plate defining a stable mobile platform, at least one movement device configured to enable movement of the stable mobile platform, at least one stabilizing actuator configured to deploy a stabilizer to engage with a surface, the at least one stabilizing actuator moveable between a deployed state in which the stabilizer contacts a surface and a mobile state in which the at least one movement device contacts the surface, and a platform controller configured to drive movement of the stable mobile platform by controlling operation of the at least one movement device when the at least one stabilizing actuator is in the mobile state, and a mounting frame mounted on the base plate of the platform.
In addition to one or more of the features described above, or as an alternative, further embodiments of the systems may include a coordinate measurement device mounted to the mounting frame.
In addition to one or more of the features described above, or as an alternative, further embodiments of the systems may include that the coordinate measurement device is a laser tracker 3D coordinate measuring device.
In addition to one or more of the features described above, or as an alternative, further embodiments of the systems may include that the mounting frame is a tripod.
In addition to one or more of the features described above, or as an alternative, further embodiments of the systems may include a battery pack suspended from the tripod.
In addition to one or more of the features described above, or as an alternative, further embodiments of the systems may include at least one sensor configured to track a position of the stable mobile platform within an environment, wherein the at least one sensor is configured in communication with the platform controller.
In addition to one or more of the features described above, or as an alternative, further embodiments of the systems may include a remote computing system configured in communication with the platform controller, wherein the platform controller is configured to receive instructions from the remote computing system.
In addition to one or more of the features described above, or as an alternative, further embodiments of the systems may include that the platform controller is configured to autonomously control movement of the stable mobile platform when in the mobile state.
In addition to one or more of the features described above, or as an alternative, further embodiments of the systems may include an inertial movement unit mounted to the stable mobile platform and configured to track a position of the stable mobile platform and in communication with the platform controller.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
A coordinate measurement device 101 is shown in
The coordinate measurement device 101 in
The base assembly 111 includes a base pan 135, which may include a handle, an air intake, and a fan that serves as an air exhaust, as will be appreciated by those of skill in the art. In an embodiment, the base assembly 111 further includes an interface panel 137 having a number of buttons, ports, and indicator lights. Various features and aspects of the interface panel can include, without limitation, an on-off button and a Wi-Fi (IEEE 802.11) button. In some embodiments, indicator lights can be arranged on the interface panel 137 (or elsewhere on the base assembly 111) to indicate laser power, system health, tracker Ethernet (IEEE 802.3) activity, and/or six-DOF Ethernet activity, for example.
In some embodiments, for example, the interface panel 137 can include one or more ports for receiving cables. In one non-limiting example, a sensor port may accept an air temperature sensor cable, material temperature sensor cable, or other temperature sensor cable. The temperature sensor cable can attach to the interface panel 137 at a respective sensor port with a connector and may be configured to detect or sense temperatures with a cabled temperature sensor. Similarly, a material temperature sensor cable can attach to the interface panel 137 at a tracker temperature sensor port with a respective connector and be configured to sense material temperature with a cabled material temperature sensor. In some embodiments, the interface panel 137 can include a power-input port that receives power from a power cable, which can attach using a connector to the power-input port. The power cable may attach with another connector to an external power supply. In some embodiments, various ports of the interface panel 137 can provides communication connections (e.g., Ethernet) for bidirectional communication between a computing device and the coordinate measurement device 101. Additional ports can enable connection with an auxiliary box, which may provide auxiliary interface signals. The auxiliary interface signals can include power signals, trigger signals, synchronization (sync) signals, time signals (e.g., time stamp), with any of such signals being unidirectional or bidirectional. In some embodiments, the connections with the interface panel 137 can provide for industrial Ethernet having protocols that provide determinism and real-time control. Examples of protocols for industrial Ethernet include EtherCAT, EtherNet/IP, PROFINET, POWERLINK, SERCOS III, CC-Link IE, and Modbus/TCP.
Turning to
In an example operation of a coordinate measurement device in accordance with an embodiment of the present disclosure, the battery pack 239 may be used stand-alone without being connected to an external power supply. In this mode of operation, the battery pack 239 can provide DC power through a port 251 (e.g., output) to the coordinate measurement device. In another mode of operation, the battery pack 239 may be configured to receive DC power from an external power supply. In this case, DC power may be provided from the external power supply to a port 251 (e.g., input) and pass through another port 251 (e.g., output) to provide DC power to the coordinate measurement device.
Turning now to
The mounting frame 300 includes a device mounting head 306 having an engagement element 308 for engagement with the coordinate measurement device 301 to enable mounting of the coordinate measurement device 301 to the device mounting head 306. The engagement element 308 can be threaded connection, a quick-release mechanism, a pin-lock connection, or other connection as will be appreciated by those of skill in art. To provide additional stability and lower a center of gravity of the tripod, when the coordinate measurement device 301 is mounted thereto, in some embodiments, a battery pack 339 may be connected to and suspended from the mounting frame 300. The battery pack 339 may be substantially similar to that shown and described above with respect to the
As shown in
In addition to being stationary for a given scanning or imaging operation, it may be advantageous to move the coordinate measurement device mounted to the tripod. Typically, such movement can impact the scanning errors, and thus recalibration may be required. Further, moving the system may require disassembly and reassembly at a new location, which can be time consuming and intensive. Accordingly, embodiments of the present disclosure are directed to provide improved systems for enabling movement of tripod-mounted coordinate measurement devices.
Turning now to
The mounting frame 400 includes a plurality of support legs 402 having support feet 404 on ends thereof. The mounting frame 400 includes a device mounting head 406 having an engagement element 408 for engagement with a coordinate measurement device to enable mounting of the coordinate measurement device to the device mounting head 406. The engagement element 408 can be threaded connection, a quick-release mechanism, a pin-lock connection, or other connection as will be appreciated by those of skill in art. To provide additional stability and lower a center of gravity of the tripod, when the coordinate measurement device is mounted thereto, in some embodiments, a battery pack may be connected to and suspended from the mounting frame 400, as shown and described above.
The stable mobile platform 412 is a dual-platform configuration having a base plate 414 and a support plate 416. As shown, the stable mobile platform 412 is a triangular shape to enable mounting of the mounting frame 400. The base plate 414 is fixed attached to or connected to the support plate 416 by one or more plate connectors 418. The base plate 414 provides a relatively smooth and flat surface for placement and supporting of the support feet 404 of the mounting frame 400. The support plate 416 can provide additional rigidity and support to the base plate 414. The support plate 416 may also provide a surface or area for mounting components of the stable mobile platform 412. Although shown herein with two plates (414, 416) that are fixedly connected by plate connectors (418), such configuration is not to be limiting. For example, as will be readily appreciated, a single plate (i.e., the base plate 414) may be provided to support and contain all the features described herein. Moreover, additional plates or support plates may be implemented beyond just two, depending on various factors, including but not limited to, weight, structural rigidity, weight tolerance, etc. In embodiments with a single plate forming stable mobile platform, the various components may be fixedly mounted to or connected to the single plate.
As shown, mounted to the support plate 416 are a platform controller 420, sensors 422, and movement devices 424. The platform controller 420 may be operably connected to and/or in communication with the sensors 422, the movement devices 424, a coordinate measurement device mounted to the mounting frame 400, to a remote computing system, or to other components as will be appreciated by those of skill in the art. The platform controller 420 can be configured communicate over wired or wireless communication protocols/components with one or more of elements that are operably connected and/or in communication therewith. The movement devices as employed in some embodiments of the present disclosure can be configured to provide micrometer stability, such that during movement the platform remains stable with little to no fluctuation in stability.
The sensors 422 may be proximity sensors that are configured to detect the position of the stable mobile platform 412 relative to an environment around the stable mobile platform 412. For example, the sensors 422 may be configured to detect proximity to various structures of features that are external to the stable mobile platform 412 and to ensure that during movement of the stable mobile platform 412 the stable mobile platform 412 does not run into or otherwise contact any external elements inadvertently or unintentionally. Although shown with only two sensors 422 arranged at corners of the support plate 416, those of skill in the art will appreciate that a third sensor may be arranged at the corner not visible in
In some embodiments, the platform controller 420 and/or the sensors 422, or other components, may be configured to monitor the position of the stable mobile platform 412. For example, the platform controller 420 may be configured with or as a tracking system. In some embodiments, a tracking system may be implemented externally from the platform controller 420, such as a stand-alone unit or in combination/connection with the sensors 422. The tracking aspect may be implemented as an inertial movement unit, as will be appreciated by those of skill in the art. In some embodiments, the tracking can be employed to enable autonomous movement of the stable mobile platform 412. For example, a pre-programmed movement or travel instruction may be executed using the platform controller 420, with determinations of position within a given space based, at least in part, upon information from the tracking capabilities of the stable mobile platform 412. Further, in some embodiments, the tracking information may be incorporated into or integrated into data collection from a coordinate measurement device mounted to the mounting frame 400. In some embodiments, the tracking can be achieved through use of an accelerometer and/or compass integrated into, connected to, and/or in communication with the platform controller 420.
In the illustrative embodiment of
In operation, the stable mobile platform 412 will be operated, at least in part, by the platform controller 420. The platform controller 420 may receive information from the sensors 422 and other sources of information (e.g., external computing systems, etc.) to drive and move the stable mobile platform 412. As will be appreciated by those of skill in the art, the movement devices 424 must be in contact with a surface to provide mobility and move over the surface. However, when a specific or desired location is reached and imaging or other sensing is desired using a coordinate measurement device mounted on the mounting frame 400, it may no longer be desirable for the movement devices 424 to be in contact with a surface.
Accordingly, the stable mobile platform 412 is configured with stabilizing actuators 430. The stabilizing actuators 430 may be operably connected to or in communication with the platform controller 420 and are operable to deploy stabilizers 432 which may be affixed to piston rods 434. The stabilizers 432 may be pads or other footing structure or device that can be engaged with a surface to enable a stable and firm engagement therewith. The piston rods 434 are moveable by actuation to move the stabilizers 432 toward or away from the support plate 416 (i.e., deployable toward or away from a surface to be engaged with). The piston rods 434 may be actuated upward relative to the base plate 414 to cause movement of the stabilizers 432. The stabilizers 432 may be hingedly, rotatably, or pivotably attached to or connected to the piston rods 434 to allow for engagement with uneven surfaces and allow for a stable engagement of the entire stable mobile platform 412 to the surface.
The stabilizing actuators 430 may be any type of actuator as known in the art. For example, linear actuators, hydraulic actuators, electromechanical actuators, etc. may be employed without departing from the scope of the present disclosure. The stabilizing actuators 430 may be operable through control commands received from the platform controller 420 or other computing and/or control device. In some embodiments, the platform controller 420 can provide for programmed or automated movement and deployment, which may be, in some embodiments, pre-programmed into or onto the platform controller 420. In other embodiments, the platform controller 420 may provide an interface or intermediary connection between an external device and the operation of the movement devices 424 and/or the stabilizing actuators 430. Further, in some embodiments, the stable mobile platform 412 can be controlled remotely by an operator, such as by use of a joystick or other controller (e.g., general purpose computer, handheld device, etc.).
Although the present disclosure has been made with respect to a tripod mounted to the stable mobile platform for supporting a coordinate measurement device, those of skill in the art will appreciate that this is merely an example, and is not to be limiting. For example, in another embodiment a single stand or rod may be mounted/affixed to the stable mobile platform, and support a coordinate measurement device.
For example, turning to
Although shown and described with respect to a triangular stable mobile platform various other geometric shapes may be implemented without departing from the scope of the present disclosure. For example, circular or square platforms may be employed, with an appropriate number of stabilizing actuators and movement devices (e.g., omnidirectional wheels or other locomotion means) configured therewith.
Advantageously, embodiments described herein provide for a stable mobile platform for use with a coordinate measurement device. The stable mobile platform provides for mobility with respect to the coordinate measurement device within an environment while maintaining stability, and further enables deployment to provide a secure and supported position for operating the coordinate measurement device. Furthermore, in some embodiments, autonomous operation may be implemented with the stable mobile platform of the present disclosure. For example, a platform controller may be programmed to perform a predefine movement within a space based on tracking and/or proximity sensing. Further, in some embodiments, the platform controller can enable communication with a remote or connected controller (e.g., joystick) such that an operator can control movement and operation of the stable mobile platform and a coordinate measurement device mounted thereto.
While the present disclosure 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.
This application claims the benefit of U.S. Provisional Application Ser. No. 62/799,913, filed Feb. 1, 2019, the entire disclosure of which is incorporated herein by reference.
Number | Date | Country | |
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62799913 | Feb 2019 | US |