Abstract: Coiled polymer artificial muscles with both large tensile stroke and giant force generation are needed for practical applications in robotics, soft exosuits, and prosthesis. However, most polymer yarn artificial muscles cannot generate a large force or stress. Here, we report an inexpensive Twisted and Coiled Polymer artificial muscle (TCP) that performs both large isobaric and isometric contractions. This TCP can generate a tensile stroke of 20.1% and a specific work capacity of up to 1.3 kJ kg?1 during temperature changes from 20 to 180 °C. Moreover, the nylon yarn artificial muscle produced a reversible output stress of 28.4 MPa, which is 100 times larger than human skeletal muscle. A robot arm and a simple gripper were made to demonstrate the isobaric actuation and isometric actuation of our TCP muscle, repectivley. Thus, the polymer artificial muscles with dual-mode actuation show potential applications in the field of robotics, grippers, and exoskeletons and so on.

Key words: Coiled nylon muscles , · Dual-mode actuation , · Large stroke , · Stress generation