S.R. Mousavi Firdeh

Bio: S.R. Mousavi Firdeh is an academic researcher. The author has contributed to research in topics: Describing function & Control theory. The author has an hindex of 2, co-authored 3 publications receiving 19 citations.

Single‐range controller design for a cruise missile

Abstract: Purpose – The purpose of this paper is to describe the application of a systematic single‐range controller design procedure to control a cruise missile.Design/methodology/approach – The controller design approach is based on one describing function model of the missile followed by linear system identification. The missile includes discontinuous nonlinear terms, and therefore, a small signal model is not obtainable by straight linearization. Once a linear approximation to the quasilinear model of the missile is obtained, a H∞ controller is designed to achieve a robust nonlinear closed‐loop system.Findings – It is found that performance of the closed‐loop system with the applied simple controller design approach competes with one other complicated describing function‐based controller design technique.Research limitations/implications – At present, the research is limited to design of linear H∞ controllers.Practical implications – The major outcome of this paper is the verification that the applied simple de...

Computer-aided design of nonlinear H ∞ controllers using describing functions

Abstract: A computer-aided procedure for design of nonlinear Hinfin controllers for nonlinear plants, whose dynamic and static behavior are highly sensitive to the amplitude level of excitation, is presented The procedure is based on describing function concepts involving sinusoidal input describing function models of the nonlinear plant, and it includes an application of a newly developed inverse describing function technique to arrive at nonlinear gains of the Hinfin controller The procedure is applied to a servomechanism problem to demonstrate the typical results that may be achieved

Design of Nonlinear Lead and/or Lag Compensators

Abstract: A known nonlinear compensator design approach is adapted to allow design of nonlinear lead and/or lag compensators, and a number of MATLAB functions are developed that automate the compensator design procedure. With this design tool, control engineers would be able to rapidly design nonlinear lead and/or lag compensators. An example of a tutorial nature is presented.

Nonlinear Controller Synthesis for Single-Input Multiple-Output Systems with Application to Cruise Missile

Abstract: The purpose of this paper is to present a new systematic procedure for synthesis of nonlinear controllers for single-input multiple-output systems. The procedure is based on several describing function models of the plant, and the nonlinear gains are obtained via an inverse describing function technique. The procedure and associated software are applied to control the bank angle of a cruise missile. The results are compared with a linear controller and another nonlinear controller that was previously reported in the open literature; it is shown that the developed procedure has resulted in a less conservative design (i.e., performance is not sacrificed to assure absolute stability).

Single‐range controller design for a cruise missile

Abstract: Purpose – The purpose of this paper is to describe the application of a systematic single‐range controller design procedure to control a cruise missile.Design/methodology/approach – The controller design approach is based on one describing function model of the missile followed by linear system identification. The missile includes discontinuous nonlinear terms, and therefore, a small signal model is not obtainable by straight linearization. Once a linear approximation to the quasilinear model of the missile is obtained, a H∞ controller is designed to achieve a robust nonlinear closed‐loop system.Findings – It is found that performance of the closed‐loop system with the applied simple controller design approach competes with one other complicated describing function‐based controller design technique.Research limitations/implications – At present, the research is limited to design of linear H∞ controllers.Practical implications – The major outcome of this paper is the verification that the applied simple de...

Modelling, simulation, and optimization of a hot pressurization system for a liquid propellant space engine and comparison with experimental results

Abstract: The main objective of this paper is to optimize the performance of a gas generator (GGO) in order to reduce propellant consumption, flyweight, and contamination. Hence, the periodic operation of a GGO is offered. For this purpose, a non-linear modelling and dynamic simulation of a hot pressurization system is developed in order to predict the history of pressure, temperature, and mass flowrate of pressurant and propellant during the expulsion of the propellant from a tank. This model calculates the change in ullage volume owing to expulsion of the propellant. It also considers the net heat transfer in the ullage space. The new approach is validatedusing experimental results. It is noticeable that despite othermodelling approaches, the present pressurization systemmodelling is not decoupled from the turbopump system. It means that the interaction is observed between these two systems. Finally, the periodic operation of a GGO is compared with its normal performance, and acceptable results are obtained.