Film-based anisotropic balloon inflatable bending actuator

Most soft pneumatic actuators require large pressures to realize their full deformations, have a non-negligible weight from their polymeric structures and have limited bending angles. In this work, a new soft pneumatic actuator utilizing anisotropic expansion of a pocket made from two different films is presented. This actuator is capable of bending angles of 500° while weighing less than 3 g and requiring less than 3 kPa to produce its maximum bending angle. It was also shown that the actuator can produce helical deformations by simply varying the angle of the bonded lines of the actuator. The effect of its most important geometric parameters as well as the application to two types of grippers is presented that can gently but firmly grasp objects or wrap themselves around structures.