Solar.q_1: A new solar-tracking mechanism based on four-bar linkages

Abstract

This paper describes the early stages of the design process of a 2-DOF parallel mechanism, based on the use of four-bar linkages and intended to move photovoltaic panels in order to perform sun tracking. Primary importance is given to the search for a way to compensate sun–earth’s relative motions with two decoupled rotations of the panel. This leads to devise a kinematic structure characterized by a particular arrangement of the revolute axes. At the same time, the structure itself is designed in order to be slender. Subsequently, the fact that during a day the earth’s revolution around the sun has negligible effects on the apparent trajectory of the sun, if compared to the rotation around the polar axis, leads to choose a control strategy which, also thanks to the said arrangement of axes, employs only 1-DOF for most of the daytime. The tracker which employs this strategy has, theoretically, an energy consumption similar to that of 1-DOF solar trackers but a precision similar to that of 2-DOF ones.