Modelling and Controlling a Dexterous Walking Space Manipulator for In-Orbit Missions

Abstract

Robotics, Automation and Autonomous Systems are the main pillars for large-scale futuristic in-orbit missions. The state-of-the-art semiautonomous robotic manipulators in orbit are operated from the International Space Station and have limited walking features restricting their workspace. Hence, they cannot efficiently assemble complex infrastructures in-situ, such as space telescopes and space-based solar power. To overcome the technological gaps in the conventional space manipulators, the next generation of walking space manipulator, known as the End-Over-End Walking Robot (E-Walker), is introduced. The E-Walker's inbuilt redundancy and modular design offers enhanced workspace utilization, greater agility and maneuverability both for in-space missions and other terres-trial applications. The assembly mission Concept of Operations (ConOps) dealt in this paper is the modular Large Aperture Space Telescope (LAST) and presents the modelling of a fully dexterous seven degrees-of-freedom E-Walker with its gait analysis and control. The closed-loop performance of the E-Walker is analyzed under perturbed microgravity conditions using two widely used space-proven controllers a. The Proportional-Integral-Derivative controller coupled with the Computed-Torque-Controller (PID-CTC) and b. The robust H ∞ controller. The simulation results prove E-Walker's efficacy for accomplishing multiplex in-situ assembly of a large aperture space telescope.