ADAPTIVE CONTROLLER FOR STABILIZING THE INVERTED PENDULUM SYSTEM

Program year: 1994/1995Digitized from print original stored in HDRThe Inverted Pendulum System, which consists of a two-dimensional inverted pendulum mounted on a motor driven cart, is a very good model to describe an unstable system. The objective of our research is to keep the pendulum in a vertical position by asserting appropriate force to the cart. The force will then counter the torque caused by the movement of the pendulum. Using Pole Placement and State Feedback techniques, we can find that the required force is proportional to the angular displacement and angular velocity of the pendulum. This force is also influenced by the system parameters, i.e. the mass of the cart, the mass of the pendulum, and the length of the pendulum. Unfortunately, in the real-world applications, most of the time the system parameters are not known or changing with time. In such a case, we need a controller that possesses the capability to continuously and automatically monitor any small changes in the system parameters, and then appropriately adjust itself to keep the system in a stable condition. Such a controller is called an Adaptive Controller. An adaptive controller can be designed as follows. First, a Standard Parametric Model containing the unknown parameters is developed. Then, an On-line Parameter Estimation technique is used to estimate the unknown parameters. Finally, the controller is designed based on the current estimates. The block diagram as well as the MATLAB - SIMULINK circuitry of the designed adaptive controller is presented in this paper