This section describes some tests which have been carried out to characterize the soft manipulator. The motion range of the manipulator has been analyzed and the experimental stiffness has been compared with the theoretical one shown in Modeling Section.
In De Falco et al., a motion evaluation of the manipulator is reported. A 6 degrees of freedom tracking probe has been fixed on the tip of the arm and the different positions during the motion have been acquired with the Aurora EM tracking system.
The following figures show how the manipulator elongates and bends when different actuation chambers are actuated with the pressure range of 0 – 650 mbar. The colour of the curves corresponds to the actuation of the same coloured chambers.
- actON, vacON: all 9 chambers are actuated with the same pressure (650 mbar), granular jamming is simultaneously activated in all 3 modules (980 mbar vacuum pressure).
Below the experimental set-up, the results and the comparison with the theoretical evaluation are reported.
As shown, the stiffness is mainly influenced by the vacuum actuation. Theoretical results underestimate experimental ones of about 0.13 MPa, probably due to the presence of the tubes and sheath not considered in the model illustrated in Modeling Section.