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Schulze D.,Ostfalia University of Applied Sciences
Advanced Powder Technology | Year: 2011

In 2008 a round robin project on ring shear testers was initiated in order to determine a range of results for a defined bulk solid (limestone powder CRM-116), similar to a round robin project with Jenike shear testers carried out in the 1980s. All users of automatic ring shear testers RST-XS or RST-01.pc were invited to take part. Twenty-seven labs supplied results. Finally, per stress level up to 60 yield loci (21 labs) measured with the RST-XS, and up to 19 yield loci (10 labs) measured with the RST-01.pc have been received. Compared to the above mentioned tests on Jenike-type shear testers, both ring shear testers provide clearly smaller standard deviations. Thus, despite different ambient conditions, the range of results is quite narrow. With the mean values and standard deviations calculated from the ring shear tester results a kind of "reference range" is defined. This range should be matched with a certain probability with the results of future tests with the standard powder if the instructions regarding stresses and ambient conditions are followed. Thus, the results provide orientation to all users of ring shear testers RST-XS and RST-01.pc. © 2011 The Society of Powder Technology Japan. Source

Turtur C.W.,Ostfalia University of Applied Sciences
Aircraft Engineering and Aerospace Technology | Year: 2013

Purpose - The purpose of the paper is the presentation of a new source of energy, the so-called zero point energy (ZPE) of the quantum-vacuum. Same as thermal heat or as ponderable matter have been identified as a type of energy some centuries ago, space is now being identified a type of energy. The advantage of ZPE is its application, because it is an energy source with many practical advantages: clean, friendly to environment and health, extremely low cost, inexhaustible, available everywhere and at all time. It is not expected that this type of energy will be the main source for the future air transport system, which is topic of this special issue. However, if the ZPE technology is developed at a more advanced level, it might contribute as energy source for instance during taxing to a certain level. Design/methodology/approach - ZPE-converting engines can be constructed on the basis of the theory presented here, which is new. Findings - In the next steps, the technology needs to be further studied. For instance more powerful engines on the basis of his theory need to build and investigated, although the applications seem to be almost anywhere, it needs to be found out which applications are the most appropriate in the first step. Originality/value - ZPE engines exist already, but the theory of ZPE conversion is unique and new in the work presented here. It can be understood on the basis of the finite propagation speed of the interacting fields, similar to retarded potentials of Lienart and Wiechert. The experimental verification of this theory is also presented in the article here. Copyright © 2013 Emerald Group Publishing Limited. Source

Mercorelli P.,Ostfalia University of Applied Sciences
Kybernetika | Year: 2010

This paper investigates the geometric and structural characteristics involved in the control of general mechanisms and manipulation systems. These systems consist of multiple cooperating linkages that interact with a reference member of the mechanism (the "object") by means of contacts on any available part of their links. Grasp and manipulation of an object by the human hand is taken as a paradigmatic example for this class of manipulators. Special attention is devoted to the output specification and its controllability. An example design of a force controller using algebraic output feedback is presented at the end of this paper. In this example, a matrix representing a static output feedback is designed. The coefficients of this matrix are the weights for the sensed outputs. With the approach proposed in this paper, a robust decoupling is obtained between the output feedback and the contact forces and joint positions. Source

Fabbrini A.,University of Siena | Garulli A.,University of Siena | Mercorelli P.,Ostfalia University of Applied Sciences
IEEE Transactions on Control Systems Technology | Year: 2012

Camless internal combustion engines offer improvements over traditional engines in terms of torque performance, reduction of emissions, reduction of pumping losses and fuel economy. Theoretically, electromagnetic valve actuators offer the highest potentials for improving efficiency due to their control flexibility. For real applications, however, the valve actuators developed so far suffer from high power consumption and other control problems. One key point is the design of the reference trajectory to be tracked by the closed loop controller. In this brief, a design technique aimed at minimizing power consumption is proposed. A constrained optimization problem is formulated and its solution is approximated by exploiting local flatness and physical properties of the system. The performance of the designed trajectory is validated via an industrial simulator of the valve actuator. © 2011 IEEE. Source

Mercorelli P.,Ostfalia University of Applied Sciences
PRECEDE 2011 - Workshop on Predictive Control of Electrical Drives and Power Electronics | Year: 2011

This paper deals with a hybrid actuator composed by a piezo and a hydraulic part and with a switching Model Predictive Control (MPC) Structure for camless engine motor applications. In a precision control problem, nonlinearities such as hysteresis, creep etc. must be taken into account. In this paper the Preisach dynamic model with the above mentioned hysteresis is considered together with a robust switching MPC utilized to manage the hysteresis nonlinearity. Simulations with real data are shown. © 2011 IEEE. Source

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