Positioners and piezo actuators from PI and PI miCos keep Mars Curiosity roving smoothly

Auburn, MA--After a lengthy collaboration between PI (Physik Instrumente) and miCos GmbH, piezoelectric actuators from PI and positioning stages from the now PI miCos are making sure that the Mars Curiosity rover rolls smoothly over the red planet with stabilized and accurately positioned onboard instrumentation. Prior to sending the positioning instrumentation into space, many qualification tests needed to be passed.

PI's contribution to the Mars mission is the PI ceramic monolithic piezo actuators (PICMA) that are being used in the Chemistry and Mineralogy instrument (CheMin) described at http://msl-scicorner.jpl.nasa.gov/Instruments/CheMin. CheMin is an X-ray diffraction-capable mineralogy instrument whose purpose is to determine if water was present in the formation of Martian rocks and soil. The mineral powder samples are fed through a funnel into individual sample cells and the powder is shaken at variable amplitudes and frequencies in the range of 0.9 to 2.2 kHz to homogenize particle size or density segregations. The precisely controlled vibrations are generated by PICMA multilayer piezo actuators that passed 100,000,000,000 (100 billion) cycles of life testing with no failures, maintaining greater than 96% of their performance at the end of the test.

The ChemCam (chemistry and camera instrument) on Curiosity is equipped with the PI miCos MT-40 autofocus precision motorized positioning stage and consists of a laser-induced breakdown spectrometer (LIBS) and a high-resolution imaging camera. The high-power laser beam evaporates the rock and the light emitted from the plasma is analyzed with the spectrometer (see www.msl-chemcam.com/index.php?menu=inc&page_consult=textes&rubrique=64&sousrubrique=224&soussousrubrique=0&art=259 for further information). The specially modified PI miCos stage focuses the analyzing system at the desired distance by translating the secondary mirror of the telescope. Due to violent shocks and vibration during launch and landing, every component in the stage from the stepper motor to the crossed roller bearings and limit switches had to be closely examined and optimized to eliminate the possibility of failure or performance loss. For fast and precise focusing, high resolution and linearity are required and backlash has to be controlled tightly--not an easy task given the very wide operating temperature range of the instrument. Modeling and thermal compensation were used as well as special vacuum compatible lubricants for all moving parts. The stage passed all tests.

PI is present worldwide with 10 subsidiaries, R&D / engineering on 3 continents and total staff of 700+. PI LP, the US operation of piezo and nanopositioning systems manufacturer Physik Instrumente GmbH, will now handle sales, distribution and service of miCos GmbH products for the US, Mexico and Canada effective June 1, 2012 (see www.micronixusa.com/motion/news/pressdetail.cfm?pressid=5). Distribution of miCos GmbH products will be integrated in PI’s North American organization. MICOS USA will be renamed to MICRONIX USA (Irvine, CA; www.micronixusa.com) and will continue to be headed by Manfred Schneider, currently president of MICOS USA, who has successfully grown the business for miCos GmbH in the US over the past 6 years. The renamed company will continue the support of the MICOS USA-developed products. All other miCos GmbH products will now globally be marketed under the new PI miCos brand name.

SOURCE: Physik Instrumente US; www.pi-usa.us