Table 1.

Comparison of actuation method of soft robots. Bold denotes better performance. Adapted with permission.^{[ 90 ]} Copyright 2018, Springer Nature

Actuation method	Strain [%]	Work density [kJ m−3]	Modulus [MPa]	Power density [kW m−3]	Strain rate [% s−1]	Frequency [Hz]	Auxiliary equipment
Skeletal muscle	20–40	8–40	10–60	50–300	10–50	1–10	Body metabolism
PA	10–40	1–200	0.1–100	10–103	10–70	1–5	Pneumatic pump, values
LCE	10–50	1–180[ 55 ]	0.1–3	0.01–10	1–10	0.001–1	Light, heat
BHA	10–25	0.1–10	0.01–1	1–10	10–100	1–5	Biocompatible medium
SMA	4–8	104–105	28–75 × 103	103–105	10–50	0.5–5	Power supply
IPMC	0.5–10	1–10	25–2.5 × 103	0.01–1	1–3	0.1–2	Power supply
DE	1–103	102–3.5 × 103[ 91 ]	0.1–3	103–105	102–105	1–100	Power supply
HA	<87[ 84 , 92 ]	10−2[ 83 ]–102[ 93 ]	10−3–0.1 [ 94 ]	10−5[ 95 ]–35[ 96 ]	–	<1[ 97 ]	Light, heat, pH, water, etc.
TCY	0.2–90[ 98 , 99 , 100 , 101 , 102 , 103 ]	2.5 × 103 [ 104 ] –1.6 × 104 [ 105 ]	2.4 × 103[ 91 ]	1.3 × 103[ 105 ]−5 × 103[ 104 ]	15[ 98 ]–50[ 103 ]	2–12[ 79 , 99 , 100 , 106 ]	Heat, solvent