Shape-Changing Robotic Materials Using Variable Stiffness Elements and Distributed Control

McEvoy, Michael A.

Graduate Thesis Or Dissertation

Shape-Changing Robotic Materials Using Variable Stiffness Elements and Distributed Control Öffentlichkeit Deposited

Analytics

Citations

Citeable URL: https://scholar.colorado.edu/concern/graduate_thesis_or_dissertations/p8418n45f

Abstract

Tightly integrating sensing, actuation and computation into materials enables a new generation of smart systems that can change their appearance and shape autonomously. Applications for such materials include airfoils that change their aerodynamic profile, vehicles with camouflage abilities, bridges that detect and repair damage, or robots and prosthetics with a rich sense of touch. While integrating sensors and actuators into composites is becoming more common, the opportunities afforded by embedding computation have only been marginally explored.I present a composite material that embeds sensing, actuation, computation and communication and can perform shape changes by temporarily varying its stiffness and applying an external moment. I describe the composite structure, the principles behind shape change using variable stiffness and the forward and inverse kinematics of the system. Experimental results use a 5-element beam that can assume different global conformations using two simple actuators. A distributed algorithm that calculates inverse kinematic solutions for shape-changing beams with integrated sensing, actuation, computation and communication is presented for beams consisting of n segments that can change their curvature and twist, perform computation and communicate with their local neighbors. The presented method distributes the computation among the n segments by sequentially applying the damped least squares method to m-segment neighborhoods, reducing the computational complexity of each individual update to O(n). The resulting solution does not require any external computation and can autonomously calculate a curvature profile to reach a desired end-pose. Results show that the proposed distributed approach performs as well as the centralized approach and grows linearly with the number of element in the beam.

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