arXiv subjects

Markus Pagitz

Publications and source records attributed to Markus Pagitz.

5 recordsLinked to original sources

arXiv2021

Space-Time Finite Element for Sensor Fusion

Drones estimate their position and orientation with the help of various sensors. Their data streams, that differ with respect to the sampling rate and standard deviation, need to be fused to get an accurate position and orientation estimate. It is subsequently shown that a nonlinear space-time finite element and static condensation can be used to accomplish this task. This is done, for the sake of clarity, in three stages. The first stage estimates the local magnetic north vector with the help of magnetometers and gyroscopes. The second stage projects the remaining sensor data onto the plane that is orthogonal to the local magnetic north vector and the third stage solves the corresponding two-dimensional problem.

physics.data-an↗

arXiv2019

Pressure Actuated Cellular Structures

This postdoctoral thesis starts by reviewing the historic development of airplane structures and high lift devices from an engineering point of view. However, the main purpose of this document is the development of a novel concept for shape changing, gapless high lift devices that is inspired by the nastic movement of plants. A particular focus is put on the efficient simulation and optimization of compliant pressure actuated cellular structures.

q-bio.QM↗

arXiv2014

A modular approach to adaptive structures

A remarkable property of nastic, shape changing plants is their complete fusion between actuators and structure. This is achieved by combining a large number of cells whose geometry, internal pressures and material properties are optimized for a given set of target shapes and stiffness requirements. An advantage of such a fusion is that cell walls are prestressed by cell pressures which increases, decreases the overall structural stiffness, weight. Inspired by the nastic movement of plants, Pagitz et al. 2012 Bioinspir. Biomim. 7 published a novel concept for pressure actuated cellular structures. This article extends previous work by introducing a modular approach to adaptive structures. An algorithm that breaks down any continuous target shapes into a small number of standardized modules is presented. Furthermore it is shown how cytoskeletons within each cell enhance the properties of adaptive modules. An adaptive passenger seat and an aircrafts leading, trailing edge is used to demonstrate the potential of a modular approach.

q-bio.QM↗

arXiv2014

Continuum Model for Pressure Actuated Cellular Structures

Previous work introduced a lower-dimensional numerical model for the geometric nonlinear simulation and optimization of compliant pressure actuated cellular structures. This model takes into account hinge eccentricities as well as rotational and axial cell side springs. The aim of this article is twofold. First, previous work is extended by introducing an associated continuum model. This model is an exact geometric representation of a cellular structure and the basis for the spring stiffnesses and eccentricities of the numerical model. Second, the state variables of the continuum and numerical model are linked via discontinuous stress constraints on the one hand and spring stiffness, hinge eccentricities on the other hand. An efficient optimization algorithm that fully couples both sets of variables is presented. The performance of the proposed approach is demonstrated with the help of an examples.

q-bio.QM↗

arXiv2014

Shape Optimization of Compliant Pressure Actuated Cellular Structures

Biologically inspired pressure actuated cellular structures can alter their shape through pressure variations. Previous work introduced a computational framework for pressure actuated cellular structures which was limited to two cell rows and central cell corner hinges. This article rigorously extends these results by taking into account an arbitrary number of cell rows, a more complicated cell kinematics that includes hinge eccentricities and varying side lengths as well as rotational and axial cell side springs. The nonlinear effects of arbitrary cell deformations are fully considered. Furthermore, the optimization is considerably improved by using a second-order approach. The presented framework enables the design of compliant pressure actuated cellular structures that can change their form from one shape to another within a set of one-dimensional C1 continuous functions.

q-bio.QM↗