Design and fabrication of an intention based upper-limb exo-skeleton

Abstract

Exoskeletons are a special type of collaborative robot that can be thought of as a humanoid robot clung to a human body (or a pilot). The proposed powered exoskeleton/ robot is a 3 Degree of Freedom (DoF) robot and it relies on DC motors to apply the necessary joint torques which in turn require an input to drive these motors. The idea here is to read the pilot's intention using an array of Force Sensing Resistors (FSRs) and then parsing it through a Dynamic Intention Filter (DIF), that yields a meaningful output, necessary to drive the exoskeleton. The DIF proposed here is a novel approach that serves as an intelligent element in the system; based on various inputs, the DIF intelligently controls the motors within the predefined and dynamically-changing safe limits of a typical human arm. Nested PID controllers are used to drive the exoskeleton in "torque-control" and "position-control" modes, and a comparison is made regarding their advantages and disadvantages.