In this research, an automatic control system is designed for landing of a small helicopter on a 4 DOF moving platform. The platform has three translational and one directional degree of freedom. The controller design approach is based on development of helicopter nonlinear dynamic model into the SDC (State Dependent Coefficient) form and real time solving of state dependent Riccati equation (S...

The assessment of seismic performance of existing structures is becoming an important problem in earthquake engineering. Some important ructures are considerably old and, therefore, their strengths and ductilities are less than strength and ductility demands because of changes in codes and design methodologies. Such structures must be strengthened to resist future earthquakes. First, a structur...

in this paper coupled nonlinear equations of motion of a suspended cable with time dependent tension and velocity are derived by using hamilton’s principal. a modal analysis for a stationary sagged cable is initially carried out in order to identify the dynamic system. the natural solution is directed to compute the natural frequencies and mode shapes of the free vibration of a suspended cable....

In this paper, seismic behavior of the existing buildings equipped by friction dampers is studied. Seismic performance of6-story, 9-story and 12-story steel buildings with damper and without damper were studied. The finite element modeling technique (SAP2000 Software) is used for analysis. Time History analyzing was done to achieve this purpose. For nonlinear dynamic analysis, the responses of ...

Most of the Takagi–Sugeno Fuzzy (TSF) systems found in the literature have only used linear functions of input variables as rule consequent and can be called as TSF Models with Fixed Coefficient (TSFMFC). This paper presents TSF model with variable coefficient (TSFMVC) which can more closely approximate a class of nonlinear systems, nonlinear dynamic systems, and nonlinear control systems. It i...

Friction is a nonlinear phenomenon which has destructive effects on performance of control systems. To obviate these effects, friction compensation is an effectual solution. In this paper, an adaptive technique is proposed in order to eliminate limit cycles as one of the undesired behaviors due to presence of friction in control systems which happen frequently. The proposed approach works for n...

The assessment of seismic performance of existing structures is becoming an important problem in earthquake engineering. Some important ructures are considerably old and, therefore, their strengths and ductilities are less than strength and ductility demands because of changes in codes and design methodologies. Such structures must be strengthened to resist future earthquakes. First, a structur...