Muscle contraction hardening serves not only to enhance strength but also enables rapid reactions in living organisms. Inspired by nature, a team of researchers at Queen Mary's School of Engineering and Materials Science has successfully engineered an artificial muscle capable of seamless transitions between soft and hard states, while also possessing the remarkable ability to sense forces and deformations.
This cutting-edge artificial muscle mimics the flexibility and stretchability of natural muscle, making it an ideal candidate for integration into intricate soft robotic systems and adaptable to various geometric shapes. Withstanding over 200% stretch along its length, this flexible actuator with a striped structure exhibits exceptional durability. By applying different voltages, the artificial muscle can rapidly adjust its stiffness, achieving continuous modulation with a stiffness change exceeding 30 times. The voltage-driven nature of the muscle provides a significant advantage in terms of response speed over other artificial muscle types.
Moreover, this novel technology can monitor its deformation through resistance changes, eliminating the need for additional sensor arrangements, simplifying control mechanisms, and reducing costs. The fabrication process for this self-sensing artificial muscle is simple and reliable. Carbon nanotubes are mixed with liquid silicone using ultrasonic dispersion technology and uniformly coated to create the thin layered cathode, which also serves as the sensing part of the artificial muscle. The anode is made directly using a soft metal mesh cut, and the actuation layer is sandwiched between the cathode and the anode. After curing the liquid materials, a complete self-sensing variable-stiffness artificial muscle is formed.
The potential applications of this flexible variable stiffness technology are vast, ranging from soft robotics to medical uses. The seamless integration with the human body opens up possibilities for aiding individuals with disabilities or patients in performing essential daily tasks. By incorporating the self-sensing artificial muscle, wearable robotic devices can monitor a patient's activities and provide resistance by adjusting stiffness levels, facilitating muscle function restoration during rehabilitation training.
The groundbreaking research conducted by the team at Queen Mary University of London signifies a significant milestone in the field of bionics. Their development of self-sensing electric artificial muscles holds promise for advancing soft robotics and medical applications.