Mechatronics Research Group, Department of Mechanical and Manufacturing Engineering, University of Melbourne, Victoria, Australia 3010. alhs@mame.mu.oz.au|Mechatronics Research Group, Department of Mechanical and Manufacturing Engineering, University of Melbourne, Victoria, Australia 3010. alhs@mame.mu.oz.au|Mechatronics Research Group, Department of Mechanical and Manufacturing Engineering, University of Melbourne, Victoria, Australia 3010. alhs@mame.mu.oz.au