Active articulation for future space applications inspired by the hydraulic system of spiders.

This paper presents and discusses a novel mechanism which was conceived taking inspiration from the micro-hydraulic system used by spiders to extend their legs. The mechanism has the potential to be used in future space applications, although the harsh space conditions, and in particular outgassing, should be carefully addressed in the design of a space-qualified model. The new system has one degree of freedom and is actuated by a pressurized fluidic system. The prototype, which has been designed, simulated, built and tested, is of compact size and presents a repeatable behaviour. The relation between pressure and rotation is approximately linear. The mechanism is suitable for a modular configuration in which several elastic joint modules are joined together. This modular configuration allows large rotations and does not increase the complexity of the actuation. A single module bends about 1.8 degrees when the pressure of the working fluid is 1.2 MPa.