a, CAD model of a four-bladder actuator design. Other than bladder number, the design is similar to the actuators illustrated in Fig. 4a. b, EMB3D-printed actuator is shown before inflation. c, Actuator inflated to working pressure. Scale bars in b and c, 5 mm. d, Pressure versus displacement curves for four-bladder actuators with varying hyperelastic-layer thickness, h (see legend; values in micrometres). The data points reported are the mean inflation displacement angles for two representative actuators over five inflation cycles and the shading indicates 95% confidence intervals. e, f, Blocked force versus pressure curves for two-bladder (e) and four-bladder (f) actuators of varying hyperelastic-layer thickness, h (see legends; values in micrometres). The lines shown are third-degree polynomial fits of data collected from five inflation–deflation cycles of representative actuators. The shaded regions indicate 95% confidence intervals. Detailed procedures for characterizing actuator performance are provided in Methods.