MODULAR ORIGAMI-BASED SOFT PNEUMATIC ACTUATORS FOR A WEARABLE SUPERNUMERARY ROBOTIC ARM IN HUMANROBOT COOPERATIVE TASKS
Khin Phone May, Marcelo H. Jr. Ang, Chen Hua Yeow
National University of Singapore, Singapore
Actuators, which are commonly used in conventional robotic technology, are assembled using “hard” materials such as metals. As such, these structures can weigh heavy and are rigid, making them unsuitable to perform delicate tasks or interact with humans. “Soft” robotic technology utilizes compliant materials to create “soft” actuators, which are commonly developed using elastomers as the functional material. The soft actuators would have internal chambers of variable design. Hence, when the actuator is activated by means of pneumatic or hydraulic source, the mode of actuation and the magnitude of force produced by the actuator can be controlled. The non-linearity of response enables the soft actuators to perform tasks such as grasping, which would otherwise be harder to achieve using conventional rigid actuators. This paper aims to further explore the materials, which can be used to build soft actuators. Thermoplastic polyurethane coated textiles are used to create modular units of origamibased airtight structures. Upon air pressurization, the pleated structure of each module of actuator would unfold and the inflated pleats would exert compressive force against the wall of the adjacent actuator unit. Upon serial arrangement of these modular pleated actuators, the mode of the actuation of the structure and the resultant force generated can be customized. Experimental analysis is carried out to analyze the behavior of the actuator, i.e. range of curvature and the force generated, under different pneumatic pressure. The array of pleated actuators can be integrated with inflatable beam modules to be further developed into a wearable supernumerary robotic arm for human-robot cooperative tasks.