Résumé
Soft tensegrities are prestressed assemblies of soft elastic cables and rigid bars. They combine the interest of tensegrities, with high payload to weight ratio, stiffness tunable by the internal prestress, and the interest of soft robots with a large compliance thanks to the use of soft elastic cables. Their use is hampered by their difficult manufacturing due to a complex spatial arrangement of cables and bars and the use of soft materials for cables. In this paper, we propose a method for the design and manufacturing of both tensegrity structures and tensegrity mechanisms. We consider their production using bi-material additive manufacturing and silicone deposition. The proposed method relies on the design of specific tooling simultaneously with the tensegrity. This tooling eases the control of the tensegrity geometric arrangement and makes possible the introduction of prestress in the structure. The method is then applied to obtain planar and spatial soft tensegrity structures and a soft tensegrity mechanism. The capability to obtain variable level of prestress, and how it can be leveraged to achieve variable stiffness is also shown.