Retracted Tentacle Membrane Tensegristat Concept Inflated Tentacle P3, V3 Stub P2, V2 Shape-Change Tendon Motion Tendon Tentacle P1,V1 Gripper (a) Tendon 2 3 4 5 6 7 1 Pump 0.01 0.1 110 Time, Log Scale (s) (b) ∆P 0.2 0.4 0.6 05 10 15 20 25 30 35 40 45 ∆P (kPa) (c) FIGURE 1. (a) The tensegristat concept. The structure derives from tensegrity between the pressurized internal fluid and the tensioned membrane and tendons. A tensegristat robot can be made to switch between a selection of different pressurized appendages. (b) Setup and results from the experiment comparing an untethered tendon actuator (as used in a tensegristat) with a typical untethered pneumatic actuator. When the mass is lifted fully to the end position it closes a circuit, which shuts off the measurement. Note: we plotted the trendlines without the datapoints because of crowding due to the log scale. The shading represents standard deviation between runs. (c) Setup and results from the experiment comparing everting shape change (as in a tensegristat) with stretching-based shape change. Shading again denotes standard deviation between runs. 22 IEEE ROBOTICS & AUTOMATION MAGAZINE SEPTEMBER 2023 Everting Unconstrained Stretching Inextensible Hoop Fibers x ∆P x ∆P x L0 h Tendon Pneumatic Total Energy 0.4 J Tendon 14.2 J Pneumatic Motor Const. P h Pneumatic Strain (L - L0)/L Power (W) End Position: Height = h