Thermo-Pneumatic SMA Artificial Muscle for Enhanced Pumpless Pneumatic Actuation

Several actuators using pneumatic pressure have been developed to create light and flexible movements in various soft robot fields. However, various systems such as pneumatic pumps and regulators are required to use pneumatic pressure. To simplify this pneumatic system, this study introduces an actuator that increases pneumatic pressure through heating of the air and simultaneously operates a shape memory alloy to create linear movement through a driving method that integrates the two forces. To confirm that it was strengthened by SMA, the displacement and pressure were measured and compared at each driving force (Heat expansion & SMA, SMA, Heat expansion), and the increased driving force was confirmed. Additionally, to verify high performance, the increased chamber with 80 SMA springs fabricated, and the displacement control at a weight of 20 kg was performed. For displacement control, a PID controller was applied to the PWM control method for the power applied to the nichrome wire.