Movie S7. Application on a fabric-based finge

2.5.3 Quadruped robot

To verify the potential application of the Triple Bellows, we adopt an electronics-free soft-legged design \cite{Drotman.2021} and fabricate a quadruped robot (Figure 5, Supplementary Note 8,  and Movie S8). The quadruped robot (244.1 g with a body length of 220 mm) constitutes four Triple Bellows, whose chambers are connected to form three groups numbered in color (Figure 5a and b). By sequentially actuating these chambers, we let the robot walk on a 900 mm floorboard and record the walking performance (Figure 5c). According to the results in Figure 5d-f, both the step frequency and walking velocity with our IEAR mechanism are markedly more than that with DIDO for the full range of pressures, while IEAR consumes much less energy per step than DIDO. Typically when \(p_{high}\) =75 kPa, the walking time with IEAR (64.5 ± 2.3 s) is 30.6±4.4 s shorter than that with DIDO (95.1 ± 3.7 s), and the energy consumption per step with IEAR (16.53 ± 0.82 mWh·step-1) is 39.4% less than that with DIDO (27.27 ± 1.42 mWh·step-1). Moreover, the steplength with DIDO is smaller than that with IEAR, which reflects the smaller air supply with the DIDO mechanism (Figure 5f). For the quadruped robot, the supplied air pressure \(p_{tank}\)  and system power are also slightly ameliorated (Figure S8g-i). Compared with the robotic fin and fabric-based glove, the large air consumption of the quadruped robot might reduce the extra improvement of  \(p_{tank}\) and system power.