René Theska

Providing target performance indices when automating the assembly of microscope objectives

This paper discusses problems of providing target performance indices of series-produced microscope objectives when they are being automatically assembled and during the monitoring of such aberrations as spherical aberration and coma. The results of computer modelling of an immersion microscope objective with an OSKh-100 “infinity” tube are presented, demonstrating the possibility of compensating the influence of primary process errors of the objective elements on the image quality of a point object by choosing the thickness of the distance ring and the relative rotation of the mounts inside the supporting base cylinder.

The concept of an automatic assembly line for microscope objectives, based on adaptive selection of their components

This paper discusses the problems and concepts of the construction of an automated line for the assembly, adjustment, and quality monitoring of series-produced microscope objectives.

Design and Experimental Characterization of a Flexure Hinge-Based Parallel Four-Bar Mechanism for Precision Guides

This paper presents the investigation of the influence of the flexure hinge contour in compliant linkage mechanisms for precision engineering applications. Especially the influence on the precision of the path of motion and the stroke of the compliant mechanism is reflected. Based on previous results on optimized single polynomial flexure hinges, the validity of proposed guidelines is analyzed for a combination of several flexure hinges in one compliant mechanism. A parallel crank mechanism is used as an example for a compliant rectilinear guiding mechanism with constant link orientation. The parameters of the approximated linear motion are investigated for the rigid-body model, a compliant analytic model and a FEM model. Finally these results are compared with measurement results taken at manufactured prototypes.

Estimation of clearances in the design and adjustment of barrel type lens systems

Estimation of probable clearances in the fit of the installed lenses and the impact from mounting and adjustment of units on system alignment and the resulting imaging quality has been considered. The characters of dispersion fields and acceptable deviations in mating dimensions of parts and their allowance have been analyzed for the estimation of probable clearances. Very commonly existing deviations in the clearances have a considerable systematic component due to systematic components of errors in the mated dimensions of parts. It has been shown that the assembly of lens based optical systems in horizontal position of its body allows vast reduction of the impact given by clearances on the accuracy of the alignment of the lens parts as compared to assembly in vertical position of its body, as in the this case the lens misalignment is due to errors in the diameters of lens components. For the adjustment of the quality of the image generated by the optical system it is necessary to take into account both the impact from misalignment of lens components on edge and central aberrations of the image field.

Ein kompakter Tastschnittsensor als Teil eines Multi-Sensor-Systems für Nanomessmaschinen

Zusammenfassung Es wurde ein Tastschnittsensor zum Einsatz in der Nanomess- und Nanopositioniermaschine NMM-1 als Teil eines Multi-Sensor-Konzeptes entwickelt. Um die Einbindung in einen vorhandenen automatisierten Sensorwechsler zu ermöglichen, war ein besonders kompakter Aufbau erforderlich. Der Tastschnittsensor nutzt zwei kreisförmige, strukturierte Stahlmembranen zur Führung des Taststiftes und ein Laser-Fokussensor zur Messung der Auslenkung. Zum Funktionsnachweis und zur Ermittlung der messtechnischen Eigenschaften wurde der Sensor in die NMM-1 integriert. Die Messung verschiedener Proben zeigte eine Reproduzierbarkeit im Bereich von wenigen Nanometern.

Enhanced adjustment methods for optical rotary encoders

The subjects of this paper are optical rotary encoders and methods for a minimizing of measured errors of the controlled process of rotary encoders. In addition, the paper describes measuring methods and equipment for the automated accuracy control of optical rotary encoders and a method for compensation of measured errors. The paper presents a novel special coupling device for control encoders. The design of the novel coupling device provides an unrestrained connection between controlled and reference encoders. The elaborated experimental setup increases the calibration accuracy of rotary encoders considerably.

Food Safety by Using Machine Learning for Automatic Classification of Seeds of the South-American Incanut Plant

The following paper deals with the classification of seeds and seed components of the South-American Incanut plant and the modification of a machine to handle this task. Initially the state of the art is being illustrated. The research was executed in Germany and with a relevant part in Peru and Ecuador. Theoretical considerations for the solution of an automatically analysis of the Incanut seeds were specified. The optimization of the analyzing software and the separation unit of the mechanical hardware are carried out with recognition results. In a final step the practical application of the analysis of the Incanut seeds is held on a trial basis and rated on the bases of statistic values.

A novel approach to correction of optical aberrations in laser scanning microscopy for surface metrology

In this paper, we present the design and construction of a laser scanning microscope for surface metrology. The proposed system is designed for using simple uncompensated optics in order to reduce the overall costs and the weight of the movable focusing optics, therefore improving measurement speed and system dynamics and offering the possibility of system miniaturization. In order to overcome the effects of optical aberrations in the system caused by the use of simple optics, a new approach is proposed, where the effects of these aberrations in the measurements are computationally corrected.

Padrão Primário para Baixo Torque e Esforços para Melhoria da sua Incerteza

Este artigo apresenta a analise do estado da arte em padroes de torque. Foca-se no entendimento da dificuldade em realizar torque abaixo de 1 Nm com incertezas relativas na ordem 10-5. Este limite do estado da arte contrasta com a crescente demanda por miniaturizacao e suas implicacoes em calibracao nesta faixa de medicao. Por fim, apresentam-se as iniciativas de avancar o estado da arte em padrao primario de torque para esta faixa.