Helical configuration of the stacked balloon concept to shape the helical actuator (HA). (a) Fabrication mold for casting of the units that conform to (b) the helical chambers and a detailed view showing the dimensions of their cross-sectional area. (c) The exoskeletons for (i) AAC and (iii) RAC. Inserts (ii) and (iv) show how we introduced the elastomeric units into the exoskeleton for the AAC and RAC, respectively. (ii) To assemble AAC and RAC, we glued the centre of the AAC membranes to the stacked RAC exoskeleton using chemical bonding (CA). (d) The assembled Helical Hybrid Actuator (HA). (e) Conceptual image of the HA actuated with one turn of the AAC and two turns of the RAC.