Enhanced Flexible Fluidic actuators for biologically inspired lightweight robots with inherent compliance

Abstract

The actuation principle of spider legs has served as an analogue for several technological fields. The current generation of Flexible Fluidic actuators (FFA) follows this principle and pushes their performance to meet industrial requirements. These new actuators are fabricated in a new two step vulcanization process with specially developed rubber compounds. In the first step the inner rubber boot is manufactured. The second step bonds the fiber reinforcement and the metal connectors to the inner rubber boot. The Actuators can carry a statical internal pressure of 20 bars and withstand up to 1.200.000 load cycles at an internal pressure of 6 bars. The new manufacturing process allows applying the biomimetic spider leg approach even for structural robotic links with variable stiffness. In order to exploit the potential of FFAs a compliant mechanism with integrated position sensor was developed. This flexural joint exhibits highly integrated sensors, small weight, and low friction. Over all, actuators and structural links with variable stiffness and inherent compliance as well as light weight composite joints were developed. These components serve as a platform for applications in the field of service robotics, artificial hands, prosthetics, orthotics, and human-robot interaction.