Development of an acceleration sensor incorporating a magneto-sensitive elastomer. - In: Engineering for a changing world, (2017), insges. 9 S.
The present paper introduces an operating principle and concept of an acceleration sensor with an adaptable measuring range and sensitivity basing on the adjustability of the material properties of magneto-sensitive elastomers. The development of such a sensor requires a comprehensive understanding of the behaviour of the utilized material. Therefore, the magnetic field dependent behaviour of magnetic hybrid elastomer (MHE) with embedded magnetically soft and hard particles is investigated. Free vibrations of MHE beams are executed and hereafter, the frequency and damping behaviour are established. It is shown that the change of the magnetic field caused by a vibrating MHE beam contains detailed information about its deflection. Basing on the revealed results, the acceleration sensor concept incorporating a functional MHE element is presented. The possibility to adjust the material properties of this element with an externally applied magnetic field is used.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2017iwk-055:3
Model-based development of a compliant locomotion system for a small scout rover. - In: Engineering for a changing world, (2017), insges. 20 S.
All currently active planetary exploration robots employ wheels for locomotion. In this work an alternative robotic locomotion concept is examined: the rimless wheel, also known as whegs. It has been proven to be successful in traversing rough terrain on earth and inhibits an appealing simplicity in its mechanics and controls. These aspects along with its inherent redundancy make the rimless wheel particularly suited for planetary exploration. The rimless wheel's kinematics and compliant spokes are analytically examined using mechanical models. The dynamics of these models are explored in a computational multi-body simulation which confirms the conclusions drawn from the analytical models about running, climbing and movement on rough terrain. A parameter variation then yields a set of suitable parameters for a future scout rover. The application in sand is considered separately both analytically and computationally. Based on these results a single wheel is build and tested on the conclusions drawn from modelling and simulation. These experiments provide strong support that the two-sided goal of efficient movement on hard and flat surfaces as well as reliable negotiation of rough terrain can be achieved with the developed locomotion system.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2017iwk-012:0
Investigations on the mechanical relevance of prominent vibrissa features for surface texture detection. - In: Engineering for a changing world, (2017), insges. 9 S.
The tactile hairs of animals are used as paradigm for artificial tactile sensors. In the case of mystacial vibrissae, the animals can determine the distance to an object, recognize the shape of the object and detect the surface texture of the object. The goal is to design an artificial tactile sensor inspired by the natural paradigm. In the present work, the vibrissa and the follicle-sinus-complex are modeled as a one-sided clamped beam within the limits of the non-linear Euler-Bernoulli beam theory. The theoretical background of the function principle and the effects of typical properties of the natural vibrissa, e.g., a tapered shape and a pre-curvature while operating in surface texture detection are analyzed. The beam-surface contact is described by Coulomb's law of friction. When the beam is in touch with the surface, a quasi-static displacement of the support takes place. As a consequence of the displacement the support reactions are changing. The resulting support reactions are analyzed in parameter studies and beneficial levels of tapering and pre-curvature are identified.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2017iwk-094:0
Vibrissa-based design of tapered tactile sensors for object sensing. - In: Engineering for a changing world, (2017), insges. 13 S.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2017iwk-050:5
Object contour sensing using artificial rotatable vibrissae. - In: Engineering for a changing world, (2017), insges. 13 S.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2017iwk-049:9
Multi-segmented artificial locomotion systems with adaptively controlled gait transitions. - In: Engineering for a changing world, (2017), insges. 14 S.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2017iwk-047:1
Control of compliant robotic systems with muscle-like actuators and saturated feedback. - In: Engineering for a changing world, (2017), insges. 9 S.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2017iwk-048:9
Screw-driven robot for locomotion into sand. - In: Engineering for a changing world, (2017), insges. 13 S.
The locomotion into sand is needed in various applications, but due to the complex mechanics of granular matter it causes special difficulties. High resistance forces on penetration systems and parameter dependent behavior, like stable or instable boreholes, complicate the design of mobile robots for the locomotion in sandy soil. The most effective state of the art devices deploy hammering mechanisms. Screw-driven systems arise more and more in the literature, as they promise to be a simple, robust and low-cost solution. In this paper, an autonomous drilling robot for the locomotion into sandy soils is presented. The design is based on theoretical modeling and experimental analyses of the screw drive aiming to minimize the needed torque and to maximize the locomotion speed. The presented prototype is able to reach a depth of 20 centimeters within a minute with a torque of 0.66 Nm.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2017iwk-005:6
Approaches to the application of magnetic fluids in electromechanical drive systems. - In: Engineering for a changing world, (2017), insges. 12 S.
This paper shows the approach of applications of magnetic liquids in electromechanical drive systems. Magnetic fluids consist of colloidal ferromagnetic nanoparticles, a particle surfactant and carrier liquid. These fluids are divided into two groups called ferrofluids and magneto-rheological fluids (MRF). Both liquids are examined in two different kinds of electric motor prototypes. Following the ideas of Nethe [4], a ferrofluid is located in the air gap of an electrical drive. The influence on torque and especially heat transfer is shown by experiments. The system is also studied analytically as a classical Taylor-Couette-System. A second motor prototype is a novel and innovative magnetorheological assisted electrical machine. The construction and the functional principle are presented in this paper. In addition, some of first measurements are shown.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2017iwk-057:9
Theoretical and experimental investigations of micro robots based on piezoelectric triangular plates. - In: Engineering for a changing world, (2017), insges. 19 S.
The creation of mobile miniature robots is an advanced and promising branch of modern engineering. The most important issues in the design of such robots are the development of propulsion and energy systems. The use of miniature electromechanical systems in the technological world is growing rapidly. Considering new applications the piezoelectric drive is a practical base to create miniature robots which move on different surfaces and in different media. Due to the small dimensions and low energy supply the development of piezoelectric platforms for miniature robots in the form of spheres, cylinders, plates with support rods can effectively solve many theoretical and practical problems. To study complex stress-strain states of plate-platforms for miniature robots methods of numerical analysis (finite element calculation) are used. This allows to obtain solutions of boundary value problems for plates with various shapes in conditions of a controlled resonance. This results can be compared with experimental data. This approach leads to a significant reduction of the design costs.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2017iwk-004:8