(Nanowerk News) In a study published recently in Advanced Smart System (“Electric Sensing Artificial Muscle and Variable Stiffness”), researchers from Queen Mary University of London have made significant progress in the field of bionics with the development of a new type of electrically variable stiffness artificial muscle that has self-sensing capabilities. This innovative technology has the potential to revolutionize soft robotics and medical applications.
Hardening of muscle contractions is not only important for increasing strength but also enabling quick reactions in living organisms. Taking inspiration from nature, a team of researchers at QMUL’s School of Engineering and Materials Science have succeeded in creating an artificial muscle that seamlessly transitions between soft and hard states while also possessing the uncanny ability to sense force and deformation.
Ketao Zhang, a Lecturer at Queen Mary and principal investigator, explains the importance of variable stiffness technology in artificial muscle-like actuators. “Empowering robots, especially those made of flexible materials, with self-sensing capabilities is an important step towards true bionic intelligence,” said Dr. Zhang.
The advanced artificial muscles developed by the researchers exhibit flexibility and flexibility similar to natural muscles, making them ideal for integration into complex soft robotic systems and adapting to various geometric shapes. With the ability to withstand over 200% of the stretch along the length direction, these flexible actuators with a ribbed structure exhibit exceptional durability.
By applying different tensions, artificial muscles can rapidly adjust their stiffness, achieving continuous modulation with stiffness changes exceeding 30 times. Its tension-driven nature gives it a significant advantage in terms of response speed over other types of artificial muscle. In addition, the new technology can monitor deformation through changes in resistance, eliminating the need for additional sensor settings and simplifying control mechanisms while reducing costs.
The fabrication process for this self-sensing artificial muscle is simple and reliable. The carbon nanotubes are mixed with liquid silicone using ultrasonic dispersion technology and uniformly coated using a film applicator to create a thin-coated cathode, which also serves as the sensing part of the artificial muscle. The anode is made directly using pieces of soft metal mesh, and the driving layer is sandwiched between the cathode and the anode. After the liquid material is cured, a complete self-sensing variable stiffness artificial muscle is formed.
The potential applications of this flexible variable stiffness technology are wide ranging, from soft robotics to medical applications. Seamless integration with the human body opens up possibilities for assisting individuals with disabilities or patients in performing important daily tasks. By integrating self-sensing artificial muscles, the wearable robotic device can monitor patient activity and provide resistance by adjusting the level of stiffness, facilitating the recovery of muscle function during rehabilitation training.
“While there are still challenges to be overcome before these medical robots can be used in clinical settings, this research is an important step towards human-machine integration,” Dr. Zhang highlighted. “This provides a blueprint for the development of soft and wearable robots in the future.”
The groundbreaking study conducted by researchers at Queen Mary University of London marks an important milestone in the field of bionics. With their development of self-detecting electric artificial muscles, they have paved the way for advances in soft robotics and medical applications.