Flexible and stable grasping by multi-jointed pneumatic actuator mimicking the human finger-impacts of structural parameters on performance

Most current pneumatic actuators, whether they have a single inflation chamber or multiple inflation chambers, are driven by a single air source, limiting their ability to complete precise and targeted manipulation. This paper describes a flexible pneumatic actuator with a three-chamber structure to mimic the motion of a human finger. Each chamber, which mimics the finger joint, is independently driven by a pressurized air source, making the finger flexible enough to grasp an object according to its shape. To achieve a more extensive deformation with lower pressure, the finite element method (FEM) was used to optimize and determine the structural parameters of the actuator. Actuators, both with and without fiber-reinforcement, were experimentally investigated to determine the bending performance of the artificial finger when pressurized individually or simultaneously. A three-finger gripper fabricated based on the multi-jointed pneumatic actuator successfully grasps various objects with higher contact area compared to previous designs, which achieves more stable grasping. The current actuator is flexible and stable enough to be used for a wide range of objects with different dimensions, shapes, and textures by controlling the various chambers.