1. School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, 2052, Australia
2. The Robotics and Autonomous Systems Group, Commonwealth Scientific and Industrial Research Organization (CSIRO), Pullenvale, 4069, Australia
3. Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
4. Institute of Mechanical, Process and Energy Engineering, Heriot-Watt University, Edinburgh, UK EH14 4AS