Surrogate Models for Compliant Joints in Programmable Structures

Abstract This work focuses on compliant joints in autonomous cells. These cells preserve the underlying geometry of a triangular mesh and enable self-reconfiguration using six-bar linkages. The six-bar linkages, essential for maintaining mesh geometry, are realized as 3D-printable compliant mechanisms. However, compliance in the hinges and deviations from the desired remote center of rotation results in positioning errors. Detailed multibody models have been developed using nonlinear beam elements to accurately represent the compliant mechanisms. In order to meet the required computational real-time performance, we propose surrogate models that can accurately predict positioning errors during self-reconfiguration. Finally, these errors are corrected by solving the inverse kinematics of a hyper-redundant manipulator using the static solution of a linearized model. Our study illustrates the benefits of utilizing a surrogate model, which reduces CPU time compared to beam elements. For the first time, we have successfully corrected positioning errors within a system of cells.