Fluid-driven artificial muscles: bio-design, manufacturing, sensing, control, and applications

Developing artificial muscles that can replace biological muscles to accomplish various tasks is what we have long been aiming for. Recent advances in flexible materials and 3D printing technology greatly promote the development of artificial muscle technology. A variety of flexible material-based artificial muscles that are driven by different external stimuli, including pressure, voltage, light, magnetism, temperature, etc., have been developed. Among these, fluid-driven artificial muscles (FAMs), which can convert the power of fluid (gas or liquid) into the force output and displacement of flexible materials, are the most widely used actuation methods for industrial robots, medical instruments, and human-assisted devices due to their simplicity, excellent safety, large actuation force, high energy efficiency, and low cost. Herein, the bio-design, manufacturing, sensing, control, and applications of FAMs are introduced, including conventional pneumatic/hydraulic artificial muscles and several innovative artificial muscles driven by functional fluids. What’s more, the challenges and future directions of FAMs are discussed.