Achim Wagner Matthias Nübel Essameddin Badreddin Peter Pott Markus L. R. Schwarz Disturbance feed forward control of a handheld parallel robot. 44-51 2007 conf/icinco/2007ra1 ICINCO-RA (1) db/conf/icinco/icinco2007-ra1.html#WagnerNBPS07