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DFG
FOR 1845
UP-HPC
DFG Research Unit
FOR 1845
Ultra-Precision High Performance Cutting (UP-HPC)

Project TP 3

Electromagnetic ultra-precision linear guide

Design of the electromagnetic guide and integration in cross table at the IFW
Figure 1: Design of the electromagnetic guide and integration in cross table at the IFW


Position accuracy of the electromagnetic actuators
Figure 2: Position accuracy of the electromagnetic actuators


Decoupled control of the slide's five degrees of freedom
Figure 3: Decoupled control of the slide's five degrees of freedom

Usually, the feed axes of ultra-precision machine tools are designed to achieve the highest degree of working accuracy. This is often accomplished at the expense of position dynamics and machining speed since increased process dynamics lead to higher dynamic disturbance forces and position errors respectively. In this context, the subproject 3 of the research group FOR 1845 "UP-HPC" focuses on the development and research of an electromagnetic guide system for ultra-precision high performance machining. The objective is to increase the applicable feed rates in ultra-precision milling processes by factor 10 up to 3,000 mm/min at consistent workpiece quality, i.e. with form deviations of <0.1 µm and a surface quality of ≤10 nm.

An electromagnetic guide system prototype was developed at the IFW and integrated in a two-axis positioning stage (Figure 1). The electromagnetic actuators provide a position accuracy in the submicron range (Figure 2). The initial operation was achieved with independent PID controllers for every degree of freedom. Preliminary results show that a control algorithm with low complexity can be used to individually control the levitating slide's five degrees of freedom with an accuracy of ±0.25 µm (Figure 3).

Current work focuses on implementing a PI state space control for a further increase of position accuracy and dynamics of the electromagnetic guide.

Research institute

IFW, Leibniz Universität Hannover
Contact: M. Sc. Rudolf Krüger (krueger_r@ifw.uni-hannover.de)