Die Positionserfassung bewegter Komponenten in der Robotik und Medizintechnik wird immer komplexer und erfordert in vielen Anwendungen die gleichzeitige Erfassung vieler Freiheitsgrade eines Objektes im Raum. Das führt zur Entwicklung von 3D-Sensoren, die die Raumlage der Roboter bzw. Instrumente bestimmen können. Ein optoelektronisches und berührungslos arbeitendes Messsystem zur dreidimensionalen Positionserfassung, basierend auf einem CCD-Flächenbildsensor, wurde entwickelt. Es kann sechs Freiheitsgrade erfassen, die drei translatorischen in x-, y- und z-Richtung und die drei rotatorischen um die jeweilige Koordinatenachse. Die experimentell bestimmten Auflösungen des Systems liegen für die x- und y-Richtung bei ca. 1 mm, für die z-Richtung bei 6 mm und für die Rotationen bei ca. 1º.

A hierarchical neural-network-based approach for circuit tuning at the post-fabrication stage is proposed. In this approach, measurements that characterize the behavior of the circuit under test are first selected. The best candidates of circuit parameters for tuning are also determined. A training set comprising the selected circuit measurements is then constructed. These measurements are calculated during simulations in which the circuit parameter values are uniformly distributed in a tolerance region around their nominal values. The training set is fed to a self organizing map neural network to cluster the measurements. The generated clusters are manipulated and classified via a hierarchical circuit tuning procedure. Based on this classification, tuning values for the tuning parameters are calculated. Situations in which the circuit cannot be tuned are also addressed. Experimental results indicate that the developed approach provides a robust and efficient technique for circuit tuning.

A few years ago it became possible to carry out complicated surgical procedures in humans with the required precision by combining medical imaging (MRI, CT) with minimally invasive surgery. The confined space within these imaging systems and the resulting inaccuracies associated with the manual use of instruments increasingly make necessary the help of aids ranging from positioning systems to robotic devices, which themselves must be position controlled. A position sensor has been developed for a medical robotic system allowing the image-controlled insertion of injection needles and the simultaneous administration of different drugs. The 3D position coordinates are determined by a noncontact optical principle, which also enables simultaneous determination of all 6 basic degrees of freedom of the robotic system (3 translational, 3 rotational). On the basis of an area image sensor and the measurement of a geometrically defined structure in the path of the rays between sensor and light source, the position coordinates are calculated almost real time. Special emphasis was placed on designing the sensor system to cover a sufficiently large workspace to enable it to cover the entire intervention area. The sensor described herein determines the position coordinates in a volume of 10 x 10 x 10 cm at a resolution of up to 1 mm for translations and 1 degree for rotations.