Highest precision, robustness and reliability are the top priority properties when selecting positioning equipment for the use in science and industry. SmarAct has designed a robotic positioning system with six degrees of freedom to be used for various positioning tasks in experiments or micro-assembly setups. Its compact design results in a slim silhouette and allows large rotary angles even in confined spaces. With a smart automated calibration routine, it achieves a sphere of confusion in the single-digit micrometer range for all rotary axis.
The SMARGON is a positioning system with six degrees of freedom based on a combination of serial and parallel kinematics mounted to a heavy duty rotation stage, defining the ω-axis of the device. This rotation platform can either be a Direct-Drive or a piezo-driven stage. The sophisticated hybrid kinematic approach allows the end eﬀector which can also be a component or another payload up to 50 grams to be positioned in X, Y and Z direction and to be rotated in χ-, φ- and ω-direction.
The SMARGON control system calculates the partially parallel kinematic transformation, which allows for direct positioning of the end effector which makes the teaching of poses an easy task. The compatibility with the MCS2 Modular Control System guarantees an easy integration into existing control environments and an intuitive way to command the positioning system.
The SMARGON consists of a combination of positioning systems with five degrees of freedom mounted on top a heavy duty rotation stage. A piezo driven rotation stage or a high precision air bearing can be used for the ω-rotation of the positioning system. The five axis positioning stage allows the sample under investigation to be positioned in X, Y and Z direction and to be rotated
in the χ- and φ-direction. The SMARGON control system calculates the partially parallel kinematic transformation which allows for direct positioning and alignment in the beam. In its standard configuration, a magnetic sample holder is mounted at the frontend which offers a fast and convenient way to load and unload different samples.
This high precision goniometer was especially designed for the use in X-ray diffraction experiments. Therefore, SmarAct devoted particular attention to the six degrees of freedom of the SMARGON positioning system.
The goniometers overall compactness and its small footprint help to minimize self-shadowing effects. This also allows the X-ray detector to be placed much closer to the sample, yielding a larger portion of the diffraction cone to be detected. SmarAct is also able to offer the SMARGON in a vacuum compatible version or fully made out of non-magnetic materials.
The sphere of confusion of the entire setup represents the overall performance and strongly depends on the precision of each individual positioning stage. Therefore, each stage is accurately aligned to ensure synergy in the combined multiaxial system. Furthermore, a sophisticated calibration via the available Calibration Kit provides the basis of an active compensation routine which is implemented in the systems motion controller. The following table provides an overview of the system specifications determined during on site operation after successful calibration
|Travel Range||unlimited||0° ... 90°||unlimited||± 2 mm||± 2 mm||± 2 mm|
|Sphere of Confusion [µm]||< 1||< 7||< 7||--||--||--|
|Resolution of Motion||< 100 µ°||< 20 µ°||< 20 µ°||< 5 nm||< 5 nm||< 5 nm|
|Velocity||180 °/s||10 °/s||80 °/s||~ 10 mm/s||~ 10 mm/s||~ 10 mm/s|
The calibration kit consists of a hardware and a software part, both designed to automatically measure deviations from an ideal rotation and to calculate compensation parameters which will be stored in the PMAC. The hardware part includes a calibration sample equipped with a ceramic sphere as test object. A three dimensional positioning system with force sensors is used to measure the lateral displacement of the ceramic sphere while the calibration sample is rotated by the SMARGON. A sophisticated routine ensures the calibration of the goniometer within minutes.
Using a SmarAct Gripping System as an end effector the SMARGON can be converted to a versatile robotic handling system. The robot can then be placed on a long linear stage rail system of the SLL Series to create the perfect solution for precise material and sample handling tasks.
An additional synergy effect would arise by the fact that it could not only be used for sample transportation from sample storages to analysis systems or microscopes but could also double as the primary sample stage for laboratories requiring high sample throughput.
The roots of the SMARGON can be found in Synchrotron XRD applications. But looking at the basis of the design one finds a universal device that can be described as a hybrid of a parallel and a serial kinematic positioning system.
With a kinematic that allows the SMARGON to translate in three dimensions and to rotate compucentric around a definable point in its working space it is not only a scientific tool but also a very versatile robotic handling system for other fields of application.
If additionally a receptacle that accepts SEM stubs is mounted as an end effector the SMARGON turns into a high precision SEM sample stage with six degrees of freedom and very thin silhouette.
Due to the availability of high and ultra-high vacuum compatible versions it can also be used as a sample manipulator for Auger- or Photo-Electron Spectroscopy or other analytical techniques that require vacuum conditions.
Combining high precision positioning with large travel ranges open up new fields of applications.
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