Printable pneumatic artificial muscles for anatomy-based humanoid robots

We propose a printable, pneumatic artificial muscle with great flexibility in design that is suitable for bio-inspired machines, especially, anatomy-based musculoskeletal robots. This artificial muscle is based on the recently developed thermal fabrication technique of inflatable actuators on sheet materials. In contrast to the cylindrical shape of the McKibben artificial muscle, the proposed actuator has a free two-dimensional shape that is less than 0.1 mm thick. We investigated known morphologies of the muscles in anatomy, such as parallel/pennate muscles, and biceps/triceps muscles. A sample of a 120 mm long and 50 mm wide rectangular muscle with a weight of 1.2 g yielded a maximum output force of up to 35 N at a pressure of 40 kPa. The data showed that the actuator can mimic the properties of the pennate muscle, which has angled muscle fibers. We also implemented muscles with anatomy-based designs on a bionic arm.