Jan Zimmermann

Kinodynamic planning - an analytical approximation with C n polynomials for industrial application

The need for n-times continuously differentiable trajectories arises when high speed, high precision control of dynamical systems is intended. Especially in mechanics, dynamical systems are usually limited in speed, acceleration and jerk. This paper introduces a strictly analytical method for generating Cn trajectories along given points under dynamic constraints and given maximum path deviations. Addressing the need for discrete time point evaluation in industrial application, a discrete time speed scheduling method is applied. By using higher order polynomials to interconnect given points along the trajectory it is shown that the resulting path complies with the given geometric and dynamic constraints. As an example, a trajectory for a given set of points is derived and the results are discussed in comparison to a computed time-optimal solution.

Motion planning for an autonomous vehicle driving on motorways by using flatness properties

In this paper, a motion planning algorithm based on differential flatness for an autonomous vehicle driving in a structured environment with moving obstacles is presented. A descriptions of the structured environment and definitions of safety and availability of the lane are proposed. In order to ensure that the trajectory is feasible and effective, dynamic longitudinal and lateral acceleration constraints are taken into account. Simulation results are validated by measurements of the outputs of a 14 degrees of freedom vehicle dynamics model with the generated trajectory as inputs.

Sensor and actuator conditioning for multiscale measurement systems on example of confocal microscopy

Multi-scale measurement systems utilise multiple sensors which differ in resolution and measurement field to pursue an active exploration strategy. The different sensor scales are linked by indicator algorithms for further measurement initiation. A major advantage of this strategy is a reduction of the conflict between resolution, time and field. This reduction is achieved by task specific conditioning of sensors, indicator algorithms and actuators using suitable uncertainty models. This contribution is focused on uncertainty models of sensors and actuators using the example of a prototype multi-scale measurement system. The influence of the sensor parameters, object characteristics and measurement conditions on the measurement reliability is investigated exemplary for the middle-scale sensor, a confocal microscope.

Modeling for Simulation and Control of a X-Y High Precision Positioning Table

The production of micro-scale objects with nano-scale properties demands for appropriate measurement and test equipment for quality control. This work is motivated by an experimental setup to proof nano-positioning capabilities with 200 mm traveling range. This paper is about the modeling of an x-y high precision positioning table, with double-H-configuration and driven by direct linear DC motors, using the Lagrange method. Furthermore the elasto-plastic friction model was extended, based on system parameters and former experiments with nano-positioning guides. The influence of the normal force on the friction force is essential for creating a connection between the macroscopic and microscopic models. A simplified model for control purposes was derived and applied to a PI-state regulator with additional feedforward of the system dynamics. Simulation results show the effectiveness of the approach.

Verlässlichkeitsanalyse von Indikator-Funktionen in einem Automatisierten Multiskalen-Messsystem

Zusammenfassung Innerhalb automatisierter multiskaliger Messsysteme werden im Allgemeinen verschiedene Sensoren in verschiedenen Skalen zur Vermessung/Inspektion verwendet. Ausgehend von der niedrigstauflösenden Skale werden Indikationen für Defekte mittels Indikatoralgorithmen gefunden. Basierend auf diesen Defektindikationen werden Unterregionen für eine Vermessung mit höherer Auflösung spezifiziert. Dieser Vorgang wird iterativ bis zur klaren Defekterkennung durchgeführt. Grundlage einer entsprechenden Vorgehensweise ist die Verwendung zuverlässiger Indikatoralgorithmen. Entsprechende Algorithmen für die Vermessung von Mikrooptiken werden vorgestellt und hinsichtlich ihrer Zuverlässigkeit analysiert. Abstract In an Automated Multiscale Measurement System (AMMS) different sensors at different scales are used for measurement and inspection of a given specimen. Starting from a coarse scale the indicators are detected by the indicator detection algorithms. Based on these indicators the regions of interest are specified for finer measurements in the next scale. This process continues until all indicators are classified. Hence reliable indicator detection algorithms are important. We present suitable indicator detection algorithms for microlens arrays and analyse their reliability.

FRICTION MODELLING FOR CONTROL OF A LINEAR HIGH-PRECISION ACTUATOR

Abstract For control applications aiming accurate positioning and exact path tracking the compensation of friction can be very important, especially when working with small displacements as usual in nano technologies. The paper at hand describes the identification of pre-sliding motion in terms of elastic and plastic movements, and the utilization of these properties for fine positioning. A feed forward control based on the model together with a simple feedback controller is used for validation of the model. Furthermore the parameters for locations with differing friction force are outlined. The axis is a linear high-precision ball bearing guide driven by a voice coil actuator and using high-resolution position measurement equipment.

Automated multiscale measurement system for MEMS characterisation

In former publications we presented an automated multiscale measurement system (AMMS) based on an adaptable active exploration strategy. The system is armed with several sensors linked by indicator algorithms to identify unresolved defects and to trigger finer resolved measurements. The advantage of this strategy in comparison to single sensor approaches is its high flexibility which is used to balance the conflict between measurement range, resolution and duration. For an initial proof of principle we used the system for inspection of microlens arrays. An even higher challenge for inspection systems are modern micro electro-mechanical systems (MEMS). MEMS consist of critical functional components which range from several millimeters down to micrometers and typically have tolerances in sub-micron scale. This contribution is focused on the inspection of MEMS using the example of micro calibration devices. This new class of objects has completely different surface characteristics and features hence it is necessary to adapted the components of the AMMS. Typical defects found on calibration devices are for example broken actuator combs and springs, surface cracks or missing features. These defects have less influence on the optical properties of the surface and the MEMS surface generates more complex intensity distributions in comparison microlense arrays. At the same time, the surface features of the MEMS have a higher variety and less periodicity which reduce the performance of currently used algorithms. To meet these requirements, we present new indicator algorithms for the automated analysis of confocal as well as conventional imaging data and show initial multiscale inspection results.

Model-Based Control of a High-Precision Measurement Machine for Multiscale Inspection Tasks

Abstract Quality inspection of micro systems on wafer scale must cope with opposing demands: nanometre accuracy and high velocity in a comparatively large workspace. An Automated Multiscale Measurement System (AMMS) combines multiple sensors that operate at specific scales by an intelligent measurement strategy in order to balance speed and accuracy. The AMMS demonstrator is based on a modified Mahr MFU100 with a position and tilt measurement resolution of 1 nm. In this paper multiscale models of a horizontal linear axis with an operating range of 200 mm and their application to state linearization and control parameterization of the residual dynamics are developed and discussed. Main modeling issues are sliding and submicron presliding friction for model-based control, reaching from submicron positioning to high-velocity trajectory tracking with desired performance. Therefore, sliding friction parameters and the friction state of an elasto-plastic friction estimator are adapted online. Experimental results show the effectiveness of the approach for fast submicron and large scale positioning.

Fusion multimodaler Daten am Beispiel eines Mikrolinsen-Arrays (Multimodal Data Fusion Exemplified on a Microlens Array)

Die Zusammenführung von Messinformationen aus verschiedenen Verfahren ermöglicht eine einheitliche und umfassende Charakterisierung von 3D-Geometrien und deren Kenngrößen. Es werden Methoden zur Verarbeitung, Vereinigung und Auswertung von multimodalen und multiskaligen Messdaten vorgestellt und anhand beispielhafter Messungen konkretisiert. Ein eingesetzter Probenkörper, basierend auf einem Mikrolinsenarray, wird mittels taktiler, konfokaler, interferometrischer Verfahren sowie Röntgentomographie und Streulicht untersucht. Anhand der resultierenden Messdatensätze werden Rauheitsspektren berechnet und diese wiederum zu einem gemeinsamen Rauheitsspektrum des Probenkörpers fusioniert. Nach der Registrierung der Datensätze mittels einer Pyramidenstruktur und Referenzmarken wird ein multimodaler Vergleich der verwendeten Messgeräte möglich. Merging information from different measurement procedures enables consistent and extensive characterization of 3D geometries and features. Methods of processing, merging, and analyzing multimodal measurement data are shown and used with exemplary measurements. The test specimen, based on a microlens array, is examined by means of atomic force and confocal microscopy, white-light interferometry, computed tomography, and angle-resolved scattering. The power spectral densities of selected data sets are evaluated and merged to a single power spectral density of the test specimen. The different data sets are registered using a reference structure with reference markers, thus enabling a multimodal comparison of the respective measurement instruments.

Virtuelle Messgeräte: Definition und Stand der Entwicklung (Virtual Measuring Instruments: Definition and Development Status)

Die Mikro- und Nanotechnologie gehört zu den Schlüsseltechnologien des 21. Jahrhunderts mit hohen Wachstumsprognosen, wie auch die im Auftrag des BMBF durchgeführte Studie “Nanotechnologie als wirtschaftlicher Wachstumsmarkt” von 2004 ausführlich darstellt. Aus diesem Trend resultiert ein steigender Bedarf an Messsystemen, die Nanostrukturen prozessnah bzw. im Fertigungsprozess charakterisieren können. Virtuelle Messgeräte liefern Erkenntnisse zur Entwicklung neuartiger Messsysteme, Analyse und Optimierung bestehender Verfahren sowie die Bestimmung der Messunsicherheit und modellbasierten Korrektur systematischer Fehler. Der virtuelle Messprozess umfasst neben dem Messmittel auch die Probe und die Wechselwirkungen zwischen beiden. In diesem Beitrag werden virtuelle Messgeräte vorgestellt sowie deren Anwendung diskutiert. Micro- and nanotechnology experienced a high economic growth in recent years. This yields in a growing demand for measuring instruments which are closely linked to the production process. Virtual measuring instruments provide knowledge for the development of new systems, the analysis and optimization of established devices as well as the determination of the uncertainty in measurement. The virtual measuring process consists of the measuring instrument, the sample, and the interaction between both. In this article examples of current developments of virtual instruments are presented and their way of utilization is discussed.