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Dadalau A.,Institute for Control Engineering of Machine Tools and Manufacturing Units ISW | Verl A.,Institute for Control Engineering of Machine Tools and Manufacturing Units ISW
Production Engineering | Year: 2012

In this work a new efficient finite element (FE) model for rolling contact [RiBEM (rigid ball with equivalent material)] is shortly presented. The RiBEM model is used to efficiently compute the eigenmodes of a linear guide system. Experimental modal analysis of the real linear guide shows with 5 % error a very good correlation with the numerical results. Although the new contact model reduces computational time by more than ten times compared with the standard FE model, it is still too expensive for use within whole machine tool models. For this reason an equivalent, mesh independent and geometrically scalable model (rolling contact spring) based on the Hertz theory is introduced and also validated with the help of modal measurements. As a justification for the presented work, results with stiffness data from the manufacturer are also presented and less correlation with the experiment is found in this case. © 2012 German Academic Society for Production Engineering (WGP). Source


Eberspacher P.,Institute for Control Engineering of Machine Tools and Manufacturing Units ISW | Verl A.,Institute for Control Engineering of Machine Tools and Manufacturing Units ISW
Procedia CIRP | Year: 2013

Industrial manufacturing has started focusing on the topic of energy efficiency already some years ago. Nowadays, even machine controls are equipped with possibilities to switch the machine into energy saving modes or even to shut it down entirely based on fixed time intervals or manually. The developed combination and modification of state-based consumption modeling with graph-based optimization theory enables the control to choose the energy-optimal state sequence for given unproductive times. The approach is presented in detail and its saving potential is demonstrated by a usage scenario from an industrial setup. © 2013 The Authors. Source


Altintas Y.,University of British Columbia | Verl A.,Institute for Control Engineering of Machine Tools and Manufacturing Units ISW | Brecher C.,RWTH Aachen | Pritschow G.,Institute for Control Engineering of Machine Tools and Manufacturing Units ISW
CIRP Annals - Manufacturing Technology | Year: 2011

This paper reviews the design and control of feed drive systems used in machine tools. Machine tool guides designed using friction, rolling element, hydrostatic and magnetic levitation principles are reviewed. Mechanical drives based on ball-screw and linear motors are presented along with their compliance models. The electrical motors and sensors used in powering and measuring the motion are discussed. The control of both rigid and flexible drive systems is presented along with active damping strategies. Virtual modeling of feed drives is discussed. The paper presents the engineering principles and current challenges in the design, analysis and control of feed drives. © 2011 CIRP. Source


Vivanco J.M.,Institute for Control Engineering of Machine Tools and Manufacturing Units ISW | Keinert M.,Institute for Control Engineering of Machine Tools and Manufacturing Units ISW | Lechler A.,Institute for Control Engineering of Machine Tools and Manufacturing Units ISW | Verl A.,Fraunhofer Gesellschaft
Procedia CIRP | Year: 2016

Multi-core processors offer a performance increment compared to single-core platforms. This leap in performance is desired to be ported to computerized numerical controls. However, in order to profit of the benefits multi-core processors can bring, the software has to be tailored to real parallel execution. In this paper a concept is proposed for partitioning numerical control software functions for being concurrently executed on multi-core systems. Specifically, the interpreter and the cutter radius compensation modules have been analyzed for devising a feasible parallel architecture. The parser algorithm has been implemented following the proposed scheme in a thread-based approach. Experiments were conducted under a real time Linux kernel extension utilizing the PREEMPT-RT patch. The results were compared against its serial version in terms of execution times to validate the concept. © 2016 The Authors. Source


Frey S.,Institute for Control Engineering of Machine Tools and Manufacturing Units ISW | Dadalau A.,Institute for Control Engineering of Machine Tools and Manufacturing Units ISW | Verl A.,Institute for Control Engineering of Machine Tools and Manufacturing Units ISW
Production Engineering | Year: 2012

Ball screw feed drives are the most commonly used mechanism to provide linear motion in high speed machine tools. Position accuracy and the achievable closed loop bandwidth of such drive systems are usually limited by the structural vibration modes of the mechanical components. Higher order plant models allow for a better understanding of the system dynamics, improve the design process of feed drives and are essential for the development of sophisticated control strategies. The ball screw shaft, describing a complex flexible structure, is probably the most significant component concerning structural vibration modes of a feed drive. In this paper, the behavior of the shaft and its dominant influence at different operating and coupling conditions is particularly addressed. Using a hybrid modeling technique, the main characteristics of the shaft are derived and projected onto a clearly arranged and versatile lumped mass model. Simulative and experimental examinations are conducted and a parameter analysis is performed. The presented model proofs to be accurate for a great range of parameters and in addition allows for a physical interpretation of the dominant structural vibration modes of a feed drive. © 2012 German Academic Society for Production Engineering (WGP). Source

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