However, the free blade design can change the windward blades angle, and the acting force on the blade can work more efficiently.On the other hand, blades are set free in the upwind stroke.

• 本研究所提出之活动式叶片，其迎风侧能改变叶片角度，使迎风叶片保持正向受力，但逆风侧时可随风摆动降低其逆风阻力。