SYNTHESIS AND ANALYSIS OF CONTROLLER BASED ON BACKSTEPPING CONTROL TECHNIQUE FOR LINEAR INVERTED PENDULUM

Abstract

Backstepping control technique is a Lyapunov based nonlinear robust technique which is applicable to only strict feedback system. Backstepping control technique has been applied on Linear Inverted Pendulum (LIP) system which is under actuated so that LIP is swung from its pendant position and gets stabilize at its upright position. Swing up is achieved by nonlinear Backstepping controller but the LIP is having unstable zero dynamics. So new Linear Backstepping controller is proposed which stabilize both the angle & position at upright position with the help of integral regulated variable in which Backstepping design is applied by making axis transformation and also with help of partial feedback linearization. In practical control system, the model which represents the control system might not he precise due to aging problem which causes the perturbation in parameter. This perturbation in parameter causes unsatisfactory performance of controller and might make system to become unstable. To overcome this problem Adaptive Backstepping control technique has been used here which is able to alleviate the perturbation in parameter prescribed in within the bounded region along with ensuring the stability in Global asymptotically stability (GAS) as compared to any conventional controller like PID. In Adaptive Backstepping algorithm, the Feedback control law designed by Backstepping is made adaptive by including parameter estimation mechanism which converts static feedback control law into dynamic control law to accommodate the perturbation in parameter with the help of integral regulated variable upon which Backstepping algorithm is applied. But control effort is increased in Adaptive Backstepping control Technique in large extent due to handling of external disturbances and parameter variation of plant. This problem is removed by combination of Exact Feedback Linearization and Lyapunov Based control algorithm. This control algorithm provides stability in GSA through Linearization, angle reference switching and energy control. Simulation results show the effectiveness such as great anti-interference capabilities and good control effects of adaptive Backstepping control technique.