Application of optimization techniques for generating trajectories and adjusting the controller gains of a hydraulic servo-positioner using the Firefly metaheuristic algorithm

This work evaluates the influence of the reference trajectory on the tracking error in a servo-positioner control system. Thus, the objective is to improve the ideal tuning of the gains of a controller applied to the tracking of the positional trajectory of a hydraulic actuator through the physical characteristics of the plant and the trajectory. The applied controller uses a cascade strategy and consists of dividing the mathematical model into two interconnected subsystems, one hydraulic and the other mechanical, applying specific control strategies to each subsystem. The proposed methodology is implemented using the Firefly Metaheuristic Algorithm (FMA). The first stage consists of generating the 5th order optimal trajectories by means of b-splines functions, in which they must minimize the acceleration along the actuator's path, considering speed and flow restrictions related to the hydraulic servo-position. The second step consists in determining the effective value of the error during the execution of the trajectory and the respective gains applied to the model. The results show that this strategy proved to be useful for obtaining adequate trajectories and gains in plants with significant non-linearities, because the trajectory error was 27% lower than the empirical adjustment method of gains compared in this study.