Symmetric Reduction of Tensegrity Rover Dynamics for Efficient Data-Driven Control

TitleSymmetric Reduction of Tensegrity Rover Dynamics for Efficient Data-Driven Control
Publication TypeConference Paper
Year of Publication2018
AuthorsSurovik, D, Bekris, KE
Conference NameASCE Earth and Space Conference, Symposium on "Tensegrity - Structural Concept and Applications"
Date Published04/2018
Conference LocationCleveland, Ohio

Tensegrity robots consist of disconnected rods suspended within a network of length-actuated cables, which gives them a high degree of compliance and adaptability suitable for traversing rugged terrain. These vehicles, however, undergo complex contact dynamics that prevent the use of traditional control techniques based on mathematical analyses of equations of motion. Data-driven approaches are thus an appropriate choice for controller design, but are themselves hindered by the high number of degrees of freedom and correspondingly large state spaces.

This paper presents a scheme for exploiting the 24th-order symmetry of an icosahedral tensegrity robot to vastly reduce the breadth of the controller input space without loss of information. Symmetric properties and state reduction operations are detailed and placed in the context of a data-driven control pipeline. Results are illustrated by comparing the input and output of a locomotive controller in both raw and symmetry-reduced dynamical spaces. The findings suggest a strong relief of the data requirements for training locomotive controllers.