Fig. 2.

Actuator design. (A) Finite element (FE) simulations of the constrained recovery of the bistable–muscle pair. The vertical dashed black line separates thicknesses unable to activate the bistable element (Left) from functional thicknesses (Right). (B) Experimental and numerical correlation between the thickness of the SMP muscle and its recovery forces as well as the time that it takes to heat to its original shape. Insets show the different muscles tested. The error bars in the force readings represent the SD. The error bars for the activation times represent the errors in reading the times from video recordings of the experiments.