Large-Deformation Analysis and Experimental Validation of a Flexure-Based Mobile Sensor Node

Abstract—This paper presents a new magnetic wall-climbing car as a mobile sensor node for health monitoring and dynamic testing of large civil (ferromagnetic) structures. Unlike traditional design, where the distance between the front and rear wheel pairs is fixed, the electromagnetically driven compliant beam connecting the axles not only offers an effective means to negotiate corners when maneuvering on ferromagnetic surfaces, but also serves as a sensor attachment device. Specifically, this paper presents the design concept of a novel magnetic flexonic mobile node incor-porating a compliant beam and permanent magnets, and a 2-D model for simulating the deformed shape of the compliant beam. Simulation results show that there exist consistent relations be-tween input/output displacements and rotation angle for control implementation in sensor attachment and corner negotiation re-gardless of gravity direction or the critical force for buckling. Ex-periment results are also provided to validate the theoretical model and compare with the analysis for sensor attachment and corner negotiation. Index Terms—Buckling, compliant mechanism, constraint, flex-ible (mobile) robot, flexible structure, large deformation, sensor network. I