A low-cost sun tracking system based on image processing and a robot arm

Concentrated photovoltaics (CPV) envisages the use of optical systems built of lenses and/or mirrors to focus sunrays in highly efficient cells, thus reducing the amount of active material while increasing efficiency and energy production. When high concentration is desired, precise tracking systems must be implemented, as only direct radiation will contribute to energy conversion. This requires the development of tracking mechanisms that be compatible with the low angular displacements allowed. The higher the desired concentration, the higher the complexity and cost of typical tracking systems. This paper proposes a low-cost tracking mechanism, built by a webcam on a robotic arm, with distinct tracking modes implemented. The architecture and hardware and software components of the system are described, and its performance is assessed in clear sky and partial cloudy days. The system performance is more affected by the precision of the stepper motors used in the drive of the robotic arm, but a viable tracker, that can control large tracking structures, is built and demonstrated.