Blue blades are mounted on yellow rotor of a vertical wind turbine (VWT) by revolute joints.
Green slider has prismatic joint with the rotor.
Pink conrods of two spherical joints connect the slider and the blades.
Orange piston, which can move up down only, has planar joint with the slider.
Blue cylinder moves piston and the slider up down to set angular positions of the blades in relation with the rotor.