Design and Control of Compliant Actuation Topologies for Energy-Efficient Articulated Robots

Considerable advances have been made in the field of robotic actuation in recent years. At the heart of this has been increased use of compliance. Arguably the most common approach is that of Series-Elastic Actuation (SEA), and SEAs have evolved to become the core component of many articulated robots. Another approach is integration of compliance in parallel to the main actuation, referred to as Parallel- Elastic Actuation (PEA). A wide variety of such systems has been proposed. While both approaches have demonstrated significant potential benefits, a number of key challenges remain with regards to the design and control of such actuators. This thesis addresses some of the challenges that exist in design and control of compliant actuation systems. First, it investigates the design, dynamics, and control of SEAs as the core components of next-generation robots. We consider the influence of selected physical stiffness on torque controllability and backdrivability, and propose an optimality criterion for impedance rendering. Furthermore, we consider disturbance observers for robust torque control. Simulation studies and experimental data validate the analyses. Secondly, this work investigates augmentation of articulated robots with adjustable parallel compliance and multi-articulated actuation for increased energy efficiency. Particularly, design optimisation of parallel compliance topologies with adjustable pretension is proposed, including multi-articulated arrangements. Novel control strategies are developed for such systems. To validate the proposed concepts, novel hardware is designed, simulation studies are performed, and experimental data of two platforms are provided, that show the benefits over state-of-the-art SEA-only based actuatio

Open Source VSA-CubeBots for Rapid Soft Robot Prototyping

Nowadays, rapid robot prototyping is a desired capability of any robotics laboratory. Combining the speed of 3D plastic printing and the use of custom Open Source electronic hardware/software solutions, our laboratory successfully developed and used tools related to variable impedance robot technology. This paper describes how we capitalized the design and use of one kind of variable stiffness actuators as a modular tool to prototype and test in a quick fashion several robot capabilities. The extension of such a modular tool for rapid prototyping allowed us to use it in several applications and scenarios, including the educational setting, aiming to speed up the gap between theory and practice in robotics. The complete palette of developments of our laboratory in hardware/software as well as some robotic systems applications shown here, are open source and contribute to the Natural Motion Initiative