Reaching Law Controller for Backlash Compensation in Parabolic Antenna Systems

Presented is a study on the application of the reaching law controller for suppressing the effect of backlash disturbance in parabolic antenna systems. The parabolic antennas are reflector antennas specifically designed to work at line-of-sight, otherwise there might be interruption or stoppage of communication. Backlash is one of the interferences that may affect the operation of such systems, and researches deduce that it could be reduced using suitable control systems. This will result in a reduced down time, maintenance costs, handling system complexities and enhanced life span. Many control methods have been tested on such systems ranging from linear methods to non-linear approaches. The antenna model in this study is adopted from a previous work. This study targets the performances of the controller in the presence of backlash disturbance which was then compared with that of the PID controller. The simulation work was done using MATLAB/SIMULINK software. Results portrayed that the Constant Rate Reaching Law Controller (CRC) was able to completely compensate for the disturbance created by the presence of backlash in the system. The PID compensation was not up to that of the CRC. Therefore, the CRC showed better performance in terms of robustness. Furthermore, it indicated the suitability of the scheme for this class of plants; that is parabolic antenna systems. Further studies may aid in achieving simple as well as robust control system for such systems.