Fig. 4: Closed-loop control servos, accelerates, and robustifies the folding process.
a Averaged curvature (κavg) response to duty cycle modulation. Morphing bases {1, 2, 3, 4}, indexed in Fig. 3d, are adopted for the experiment, under recruiting the morphing basis 5 as the role of flattening. Dashed lines indicate linear fit (all show R2 > 0.95). The inset shows the region of folding by each morphing basis recruitment. b A trajectory tracking 0.09 Hz harmonic temperature input T. The inset shows a photograph of the applied folding configuration (activated region is depicted in red). c, d Frequency response in temperature control, in magnitude (c) and phase (d). Same shape configuration is adopted as (b). e, f Demonstration of thermal robustness to wind (e) and changes in ambient temperature Tamb (f). The shape configuration adopts the set of morphing bases {1, 2, 3, 5} indexed in Fig. 3d. The insets show photographs of the sheet operation. Scale bars, 15 mm. For (b–f) OL and CL denote open-loop control and closed-loop control, respectively.
