1. Institute of Systems and RoboticsDepartment of Electrical EngineeringUniversity of Coimbra Coimbra 3030‐290 Portugal
2. CEMMPRE—Department of Chemical EngineeringUniversity of Coimbra Coimbra 3030‐290 Portugal
3. Soft Machines LabDepartment of Mechanical EngineeringCarnegie Mellon University Pittsburgh PA 15213 USA