THIS paper presents a bidirectional 3D-printed soft pneumatic actuator that is capable of inward and outward bending. A direct 3D-printing approach is adopted to fabricate the actuator, which reduces fabrication complexity and allows for easy customization of actuator dimensions for various applications. To illustrate the applicability of the bidirectional actuators, four of these actuators were incorporated into a gripper system. A suite of various functional grasping tasks, such as packaging, assembly, and alignment tasks, were successfully conducted. It was observed that the unique bidirectional bending characteristic of the actuator allows the gripper to grasp objects with sizes up to 245% larger than its default grasping width. To complement the gripper system, a graphite-based flex sensor that is able to sense bending in two directions is developed to control the bidirectional actuators. A preliminary test was conducted successfully where the user controlled the gripper system to grasp, hold, and release an object using a glove with the sensors.
