Degradation test of the actuator
The circular-type actuator was placed on actinomycetes (Oki, Dr. Actinomycete)-mixed soil in an oven (Yamato Scientific, ADP 300C) at 60 °C. The oven had a small hole that allowed air to flow in, which kept the actinomycete active. The soil was collected on the campus of the University of Electro-Communications.