A comparative study of robust attitude synchronization controllers for multiple 3-DOF helicopters

Two robust controllers, a linear disturbance estimator (DE) based controller and a standard integral controller, are respectively designed for multiple 3-DOF helicopters to achieve attitude-trajectory synchronization in both elevation and pitch tracking. These two controllers are shown to have similar structure but with different tuning parameters. It is further discovered that DE benefits from a single-parameter tuning for small tracking error while the other controller requires multiple parameters. Experimental investigations demonstrate the effectiveness of both controllers as well as the differences in tracking accuracy owing to different controller parameters.