Customizable soft pneumatic finger actuators for hand orthotic and prosthetic applications

Traditional actuators are usually heavy, expensive and require a complex multi-component mechanical structure to generate human-like movement. Therefore, we proposed a lightweight soft finger actuator (25g) that is powered by pneumatic means to perform the grasping tasks. The soft actuators were fabricated using 3D-printing and soft lithography techniques. 5 healthy subjects (3 males and 2 females; age: 25±2.5 years) were recruited and they were asked to wear a hand orthosis with actuator attached on index finger to evaluate the performance of the soft actuators. The flexion angle at metacarpo-phalangeal joint is 55.7±19.0°, proximal interphalangeal joint is 141.2±2.0°, and distal interphalangeal joint is 126.6±3.0°. Also, three finger actuators were used to create a prosthetic hand, which is capable of grasping and holding objects with different sizes and weights up to 600 g. These studies showed the possibility of deploying these soft finger actuators in hand orthotic and prosthetic devices.