Development, Design and Experimental Testing of Fuzzy-based Controllers for a Laboratory Scale Sun-tracking Heliostat

Abstract

The objective of this study is to develop and design fuzzy-based controllers for experimental examination and application to a laboratory scale sun tracking heliostat with dynamic movement about azimuth and elevation axes. The experimental approach accounts for unknown parameters such as, nonlinear static and dynamic frictions, nonlinear and variant effect of gravity on system, magnetic saturation of motors, limitations of power source in supplying rush and steady current and variation in heliostat dynamics due to different spacial and time passing conditions. To meet the objective, a classical PI and PID as well as Fuzzy-PI (F-PI) and Fuzzy-PID (F-PID) controllers are designed and experimentally implemented. The performance of each controller is measured by means of evaluating a cost function that is based on the integral of absolute value of error signal. The results show that for azimuth-axis angle, the cost of F-PI controller for deviation from set point is 67% lower as compared with that of PI controller. Also, it is shown that the application of F-PI controller results in lower cost for elevation-axis angle by 36%, 40%, and 50%, when compared with PI, PID, and F-PID controllers, respectively.

Development of a DSP Microcontroller-Based Fuzzy Logic Controller for Heliostat Orientation Control

“…The algorithms of the FLC and PID controller were designed for the position control of the DC motors at no load. Both controllers were tuned to accomplish with the design parameters of 10 ms sampling time and 100 ms of rising time without overshoot for the smallest change in the reference signal in order to reduce the energy consumed by the DC motors when the heliostat is moving [27]. Figure 12 shows the block diagram of the FLC.…”

“…Finally, the FLC has also been applied in orientation control of heliostats. Ardehali and Emam [27] performed a comparison between a classical PI and PID controller, a PI-FLC and a PID-FLC for the orientation control of a laboratory-scale heliostat with two mirrors of 0.9 m × 0.7 m, two 15 W DC motors, and a data acquisition system with 20 ms sampling time. The FLC uses three membership functions in order to adjust the PID controller gains.…”