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Soft crawling robots have attracted considerable attentions due to their merits of flexibility, safety, cost, and their unique applications that are not available for the rigid robots. However, poor precision resulting from the strongly nonlinear reconfiguration prevents such soft robots from wider applications. This paper reported a novel SMA spring driven soft crawling robot with feet of constant curvature, and the constant height of the feet during crawling enabled effective alleviation of the nonlinearity of the robotic reconstruction. An analytical static model for the step length of the robot’s crawling gait was built based on 11 independent design parameters, and the influential significance of each parameter was parametrically studied based on the static model. These parameters were then qualitatively classified as strong, medium, and weak factors based on their influences on the theoretical step length of the crawling robot, among which the minimum and the maximum bending angles and the length of the silicone body functioned as the dominant factors. This work provides an efficient approach to the design, prediction, evaluation, and optimization of such soft crawling robots for diverse application surroundings.

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Solar sailing enables efficient propellant-free attitude adjustment and orbital maneuvers of solar sail spacecraft with high area-to-mass ratios. However, the heavy supporting mass for large solar sails inevitably leads to low area-to-mass ratios. Inspired by chip-scale satellites, a chip-scale solar sail system named ChipSail, consisting of microrobotic solar sails and a chip-scale satellite, was proposed in this work. The structural design and reconfigurable mechanisms of an electrothermally driven microrobotic solar sail made of Al\Ni50Ti50 bilayer beams were introduced, and the theoretical model of its electro-thermo-mechanical behaviors was established. The analytical solutions to the out-of-plane deformation of the solar sail structure appeared to be in good agreement with the finite element analysis (FEA) results. A representative prototype of such solar sail structures was fabricated on silicon wafers using surface and bulk microfabrication, followed by an in-situ experiment of its reconfigurable property under controlled electrothermal actuation. The experimental results demonstrated significant electro-thermo-mechanical deformation of such microrobotic bilayer solar sails, showing great potential in the development of the ChipSail system. Analytical solutions to the electro-thermo-mechanical model, as well as the fabrication process and characterization techniques, provided a rapid performance evaluation and optimization of such microrobotic bilayer solar sails for the ChipSail.