Ball screws are the most common elements in machine tools for transferring rotational into linear movements. Within an electromechanical machine tool axis, ball screws belong to the decisive components for achieving small positioning errors. Due to wear, the preload of ball screws decreases. This often leads to vibrations in the electromechanical power train and influences the machining results negatively. This results in the need of preload compensation systems, which ensure the required machine accuracy. In this article, an adaptronic approach with piezoelectric self-sensing transducers for an active compensation system of preload control in ball screws is presented and common results of the developed self-sensing actuator are discussed.

Up to now, the fluidics-specific operation of micro-mechatronic fluidic systems has required two parallel forms of energy (fluidic and electronic share of work and output). This incurs costs for wire routing and energy provision. The self-sufficient fluidic systems known so far work with batteries or accumulators, which also incurs high costs for maintenance and disposal. The overall increase in decentralisation and flexibilisation moves the focus more towards the aspect of installation space:  Limited installation space requires functions to be integrated in the smallest possible space  The integration of functions requires the use of micro system components The powerFLUID project aims at converting the fluid-inherent mechanical energy into electric energy, herewith supplying microtechnical function modules by using suitable conversion systems [1]. As an initial step, this article describes a general approach to selecting suitable conversion systems and to applying adequate consumer loads, like actuators and sensors. The approach is based on the precise balancing of electrical and fluid-mechanical parameters of the active system components. As a representative mechatronic system an automatic water tap with an integrated microscale turbine/generator unit is introduced. The overall system design and design parameters of the used microscale turbine/generator unit as well as the other system components like the bistable microvalve, the capacitive self-sufficient sensor and control electronics are explained. The operation of all participated micro systems in the water tap is described. Monitored long-term operations of the automatic water tap under real-live conditions are presented, pointing out the stability of the system in this harsh environment. Furthermore, investigations on the behaviour of the prototype of a microscale turbine/generator unit in fluids with a different kinematic viscosity than Proceedings of the 11 euspen International Conference – Como – May 2011 water show the influence on the power/conversion rate. A different design of the fluidic part of the microscale turbine/generator unit is deduced for fluids with relatively high kinematic viscosities. The article concludes by giving suggestions for further applicable micro products that may have an advantageous operational behaviour if designed as a micro energy harvesting system. These could be systems for water regulation in horticulture and agriculture as well as active fluidic systems in machine tools. 1 Motivation and project targets In the field of fluid technology, it is common for stored potential and kinetic energy to be dissipated to the environment without being exploited or to be converted into heat. This means that a large share of the costs and time that go into the provision of energy is ineffective. One example is the outlet air of pneumatic cylinders used in production systems, which is generally released into the environment without being exploited. For extensive systems with decentralised energy supplies it makes sense to pick up the hitherto unused energy and make it available again to the production systems. The energy must be provided in an appropriate form. Therefore, it is converted into electric energy using suitable micro generators. This allows sensors and actuators to have a local and self-sufficient electric energy supply for actuation. The powerFLUID project, funded by the German Federal Ministry of Education and Research (BMBF), aims to develop and implement self-sufficient, decentralised energy supply systems for micro system components. Electromagnetic, piezoelectric and thermal converter principles are examined to see how the energy contained in a fluid can be converted into electric energy. The results are then integrated into simple converter modules that are easy to retrofit. One of the target systems is a selfsufficient, automatic water tap. 2 Design process for energy-sufficient fluidic systems If individual subsystems of an energy-sufficient system are to be adapted and integrated into a global system, the limit values for the fluidic working range of the individual components must be identified. They can be obtained from the descriptions of the respective subsystems. The fluidic components have limits for the minimum and maximum operating pressures, and for the minimum and maximum flow rates. Therefore, if several fluidic subsystems are integrated into a global system, there is an overlap of several fluidic working ranges (see Figure 1). Proceedings of the 11 euspen International Conference – Como – May 2011

Part supply is a major bottleneck for successful automation in micro assembly. So far, vibratory conveyors working according to the micro throw principle are applied predominantly. However, missing flexibility, fault liability and abrasive wear are significant disadvantages. In this paper, a multi body simulation model describing the micro slide principle including all major influencing parameters for micro parts is presented. By means of experiments with an especially designed piezoelectric conveyor, the functionality and advantages of this principle are demonstrated and the model is validated. Furthermore, optimization of the conveyor by automation, miniaturization and modularization is shown.

Guiding systems figure amongst the central components in the flux of a machine tool. Their characteristics have a direct impact on machining accuracy. Hydrostatic guiding systems are preferably used when specific requirements are to be met with regards to accuracy, stiffness and damping. However, an active intervention in the guiding system of such conventional systems, i.e. to absorb geometrical guiding rail errors, has so far not been possible. Compared to modular, conventional systems, adaptronic systems offer considerable cost savings potentials thanks to their increased functional degree of integration [1].

Allgemein zeigen Werkzeugmaschinen Verlagerungen im statisch/quasistatischen und im dynamischen Lastbereich auf. Ziel des Projekts ist die adaptronische Kompensation dieser Verlagerungen mit paralleler Bewältigung von Sensorund Aktorfunktion. In den ersten zwei Projektphasen wurde dazu bis heute auf den statisch/quasistatischen Bereich fokussiert, um in einer weiteren dritten Phase die Ausweitung des Konzepts auf den dynamischen Bereich anzugehen. Unter Ausnutzung des Prinzips einer Schwingsaitenwaage werden statische Verformungszustände zur Messung in ein dynamisches Eingangssignal für piezoelektrische Wandler gewandelt. Bild 1 verdeutlicht hierzu den prinzipiellen Aufbau des Systems. Dr.-Ing. Christian Munzinger, Dipl.-Ing. Stefan Herder, Dipl.-Ing. Martin Weis Institut für Produktionstechnik (wbk) Universität Karlsruhe (TH) Kaiserstr. 12, D-76128 Karlsruhe Tel. +49 (0)721 / 608-2449, Fax +49 721 / 699 503 E-Mail: weis@wbk.uka.de Internet: www.wbk-ka.de