Karl-Heinz Wurst

Systematic Design of Hexapods and other Parallel Link Systems

During the last 30 years, a variety of different parallel kinematic links which are based on the known Stewart platform have been proposed and which are all inventive ideas. All existing machines, however, share the common characteristic that motion is generated either by length modification, positioning of the base points or by a combination of both. This contribution describes a systematic procedure for the design of paralllel kinematic link mechanisms which comprises a great variety of possibilities.

Thermal Behaviour of Industrial Robots and Possibilities for Error Compensation

Abstract The fundamental differences between the kinematics of SCARA-, six-axes- and portal robots as well as tripod and hexapod machines are also reflected in their varying thermal behaviour This paper describes the sequential investigation of the thermal behaviour of industrial robots with a standardized experimental setup It includes a comparison of the results for the different robot types as well as conclusions regarding improvement possibilities in robot design. There are also suggestions for the compensation of errors due to thermal effects and for a correction of the spatial position of the tool center point (TCP)

Modularity in small machine tools

Up to now, machine tools in micro production hardly feature modularity and hence offer only few opportunities to reconfigure or individualize a manufacturing process. This article gives a summary of concepts, how modularity in small micro machine tools can be designed and implemented. A size-adaptable machine frame is the basis for various possible process layouts. Adapters, a feed module with replaceable drive and kinematics, equipped with appropriate interfaces as well as a supply concept are introduced to allow further configuration. The combination of those concepts characterizes a small modular machine tool system. Technical solutions and fully functional prototypes will be shown and discussed in the following paper.

Modulkonzept für rekonfigurierbare Bearbeitungs- und Steuerungssysteme

Kurzfassung Die Integration von Mechanik, Elektrik und Software zur Mechatronik bietet bei der Konzeption von Maschinen- und Anlagenstrukturen neue Möglichkeiten durch Bildung neuartiger, in sich geschlossener mechatronischer Module. In diesem Artikel wird ein Konzept für wandelbare Bearbeitungssysteme basierend auf mechatronischen Modulen und einer selbstadaptierenden Steuerung vorgestellt. Damit ist eine schnelle und wirtschaftliche Anpassung der Produktionstechnik an die sich ständig ändernden Randbedingungen des Produktionsprozesses möglich.

Conception of Reconfigurable Machining Systems

This article gives a definition of reconfiguration and evaluates former approaches towards reconfigurable machining systems. Derived from the lack of these approaches a concept for the design of a reconfigurable machining system, including the control system is presented. The basic principle is autarkic, mechatronic components with well defined mechanical, electrical and information interfaces. The machine’s modularisation in mechatronic components and the demand for a fast and reliable reconfiguration process leads to a self-adaptable, platform-based control system. To maintain the machines production ability after reconfiguration processes an autarkic diagnostic system is introduced.

A new Communication System for Reconfigurable Mechatronic Modules

In this article, in line with a research study, analysis and investigation of a new communication system are presented to reduce interfaces and save cables for mechatronic self-sustainable modules, which will result in new modular machine concepts. The DC link of inverter driven electrical drives is used as a communication medium for transmitting data to control the drive and to get the values of sensors installed at the motor. This article deals with analysis and modeling of disturbances and with frequency domain channel and in a second step it presents simulation results of coded orthogonal frequency division multiplex (OFDM) system operating in a realistic scenario.

Fabrication of Biomimetic and Biologically Inspired (Modular) Structures for Use in the Construction Industry

The transformation of biological paradigms into building construction involves the transfer of structure and system-defining properties from biological role models to construction-specific and innovative non-construction-specific systems and processes. The challenge of manufacturing biomimetic and bio-inspired structures includes the provision of methods and procedures that allow the mapping of biological features on a production-related description. The methodological approach requires the validation and verification of existing production methods at the small scale (model, elementary cell) in order to transfer findings to the production of components at the construction scale. Additionally, the biological features that cannot be reproduced by existing methods require further adjustment or the development of new methods for appropriate transfer. A basic condition for the further development of such production procedures is the possibility of manufacturing complex structures based on biological strategies concerning resource and energy consumption, waste production and greenhouse gas emissions.

Implementation of a new communication system for reconfigurable mechatronic modules

In this article, in line with a research study, analysis and investigation of a new communication system are presented to reduce interfaces and save cables for mechatronic self-sustainable modules, which will result in new modular machine concepts. The DC link of inverter driven electrical drives is used as a communication medium for transmitting data to control the drive and to get the values of sensors installed at the motor. This article deals with analysis and modeling of disturbances and with frequency domain channel and in a second step it presents simulation results of coded orthogonal frequency division multiplex (OFDM) system operating in a realistic scenario.

Industrial powerline communication for machine tools and robotics

Nowadays, machining systems worldwide are on a very high level, regarding mechanics as well as control technology. Therefore, in the case of challenging sub-assemblies like drive and control systems and technological components (e.g. high-frequency spindles and processing heads) the emphasis should be placed on the integration of these components in specialised machine and plant configurations, especially by reducing the interfaces with a new communication system. In the future, technological innovations can be primarily expected from the introduction of highly integrated mechatronic machine modules. The concept of this new powerline communication system is the transmission of data and power for a drive unit over a common power cable. This can be achieved by high-frequency modulation of the data onto the cable. In this paper, the basic conditions for the industrial powerline communication are presented. First an overview is given on the existing communication systems in production technology. As an essential requirement the transfer function of the transmission channel is analysed. Further, the disturbances on the transmission channel are discussed. The final essential requirement is the compliance with the standards regarding elimination of disturbances, conducted as well as radiated. For proof of functionality the Orthogonal Frequency Division Multiplex- (OFDM-) transmission method is applied. This is implemented in two modems which have been set up within a demonstration system.

A novel rapid additive manufacturing concept for architectural composite shell construction inspired by the shell formation in land snails

State-of-the-art rapid additive manufacturing (RAM)-specifically fused filament fabrication (FFF)-has gained popularity among architects, engineers and designers for the quick prototyping of technical devices, the rapid production of small series and even the construction scale fabrication of architectural elements. The spectrum of producible shapes and the resolution of detail, however, are determined and constrained by the layer-based nature of the fabrication process. These aspects significantly limit FFF-based approaches for the prefabrication and in situ fabrication of free-form shells at the architectural scale. Snails exhibit a shell building process that suggests ways to overcome these limits. They produce a soft, pliable proteinaceous film-the periostracum-which later hardens and serves, among other functions, as a form-giving surface for an inner calcium carbonate layer. Snail shell formation behavior is interpreted from a technical point of view to extract potentially useful aspects for a biomimetic transfer. A RAM concept for the continuous extrusion of thin free-form composite shells inspired by the snail shell formation is presented.