Optimal nonlinear disturbance rejection control for nonlinear cascade systems

Robust backstepping control for slew maneuver using nonlinear tracking function

“…Employing terminologies of (A1) and (A2) in the Appendix, the rest-to-rest maneuvering problem corresponds to , , and . The first step in the backstepping control method is to find the control law for the subsystem described by (3). Let us consider the following candidate Lyapunov function (6) In (6), (5a) is considered as the final condition and (5b) will be incorporated later.…”

“…Recently, researches on the backstepping control method have tried to combine the backstepping control method with other control methods such as the sliding mode control law [2], optimal control law [3], adaptive control law [4]- [6], robustness accommodated control law [7], [8], and neural network theory [9], [10]. The backstepping control method can be combined as such because it mainly prescribes the controller structure.…”

On the rotating surge and stall and the polar control method

“…where PI, /32 are positive constants and w1, w2 are L2 external disturbances as defined in [2]. To analyze the system, the same disturbances used in [2] were applied i.e, w1 = 0.1e-0.5t sint and wp = 0.5e-0.05tsin0.7t.…”

“…Several variations exist on the basic model, and in this paper one such variation is used to evaluate the control law required for stabilization. To achieve stabilization, several techniques have been applied by various authors: backstepping [5], nonlinear robust control [3], and nonlinear disturbance rejection [2]. These three control techniques will be discussed, and the recently introduced polar control method [6] will be applied, and compared to previous works.…”

Nonlinear robust controller for rotating stall and surge in axial flow compressors

“…In practice, however, because of unavoidable uncertainties and external disturbances, this operating point may be perturbed into instable regions causing the instabilities mentioned above. That is the reason why, in recent years, the development of integrated control system has led to a significant activity in modeling [l, 2, 3, 41 and control [5, 6, 71 and more recently in [8, 9, Recently a robust control design approach initially developed in [13] has been applied to robustly control rotating stall and surge in axial flow compressors [14]. The performances of the resulting closed loop system have been compared to many existing stabilizing feedbacks [15, 10, 61.…”