Sharif Digital Repository

This paper is concerned with the control of a laboratory setup called the twin rotor MIMO system. A novel nested saturation controller based on well-known extended state observer is proposed. Extended state observer has been utilized to tackle control difficulties due to existence of a high coupling between system channels. Nested saturation control is also utilized to improve closed-loop performance of system considering inevitable input saturation constraint. Besides the complexity of system, the proposed method can be simply designed and implemented. Numerical simulations are utilized to demonstrate the effectiveness of proposed method in comparison with the existing ones. © 2017 IEEE  

This paper is concerned with the global stabilization of multiple integrator systems subjected to input saturation. Among the existing works, nested saturation method has been demonstrated to be an effective tool. In the present contribution, an adaptive nested saturation feedback law is proposed which takes the advantages of time varying parameters in the saturation functions along with employing the well-known extended state observer. The global stability of the proposed approach for a desired order of integrators’ chain is demonstrated. The performance of the proposed control law is compared with the existing methods in the case of a triple integrator chain. It is shown that the proposed... 

To achieve an exact three-dimensional command to line of sight (CLOS) guidance law, a novel control scheme comprising feed-forward terms (to exactly compensate known kinematics) accompanied by an adaptive nested saturated feedback strategy is presented. A square-root cubature Kalman filter is designed as the CLOS non-linear guidance filter. Performance of the proposed guidance law is compared with the augmented proportional navigation (APN), at the absence and presence of target maneuvers, autopilot dynamics and non-ideal tracking filter. Simulation results demonstrate the satisfactory performance of proposed strategy. © 2018 Concern CSRI Elektropribor, JSC  

In this paper, a novel scheme of command to line-of-sight guidance law regarding the outstanding practical limitations is proposed. With the aid of formulating problem in pursuer's line of sight frame, the exact feed-forward acceleration commands are derived for a general target motion in three-dimensional engagement geometry. Then, a nonlinear control scheme constructed from feed-forward terms along with a nested saturated feedback strategy is suggested. Two momentous practical limitations are considered. The first is related to existence of pursuer's acceleration saturation which is ignored in all existing solutions. The required conditions to insure the global stability are derived... 

This paper considers the problem of high-performance global stabilization of an integrator chain via a bounded control at the presence of input disturbance. While nested saturated feedback (NSF) is known as the most inspiring existing solution in the literature, we shall highlight the inherent shortcomings of this approach which cause a poor performance in terms of convergence rate. Then, a novel dual-mode control scheme combining an improved NSF law with a linear matrix inequality (LMI)-based model predictive controller (MPC) is developed to overcome the weaknesses of pure NSF. By offline calculations, a set of nested robust invariant attraction regions and their attributed feedback gains...