Abstract
KEYWORDS
vehicle, stability, oscillatory, analysis and semi-active
ABSTRACT
Automobile represents a very complex oscillatory system. Classic twin-shaft automobile could be observed as mechanical system with three suspensions masses, mutual connected with elastic elements. Automobile oscillations are mostly induced with road influence. The oscillations provoke addition dynamic tension of vehicle and road in one side, and in the side loads and fatigue of driver and passenger. The prices of full active suspension impede this systems to bee serially incorporated during the automobile production, many manufactures decided to use semi-active or adaptive suspensions systems. Semi-active suspension as main truss form uses classical spring and damper. Semi-active suspension also uses hydro cylinders for increasing comfort and maneuverability. Nowadays they are many construction solutions who are developing more and more in direction of minimize necessary energy for system works. Aim of this work is to enable stability analysis of nonlinear systems of automatic control using theory of Ljapunov. In that case we are not look out for every shape of nonlinearity specifically V-function. Instead of that, equations of assign nonlinear system derives by mathematical transformations on canonical form. Those parameters are used for getting stability conditions. This observation is not general, so there is special class of system witch can be analysed. The class of this systems is wide, so the process is very important for analysis nonlinear systems of automatic control. For stability research, very importance is the way how objects without regulator behave in that case. Information of stability or nonstability of discrete object is necessary for use of this proceeding. Base postulate for this application procedure is to describe behavior of object guidance with system of linear differentials equations with constants coefficient. With this equations it is very easy to diagnose stability of linear parts of systems. With previously regard, nonlinear system characteristic was consequence for regulator works. In practice, this situation is very often. Particularly, displacement of actuator of automatic system control wasn't always proportional to output signal. Action of hydraulic, pneumatic and other valves depend on nonlinear way of theirs positions. Besides of that, in regulation loop belong sensors, amplifiers and others components outside of object. This components can also may have nonlinear characteristics. Every simulation was created in MatLAB Simulink.