Abstract:
This thesis designed and implemented tha Narma-L2 neurocontroller to control nonlinear systems including water tank system and nonlinear pendulum system. The Narma-L2 neurocontroller, first, learns and models the nonlinear system, then is reconfigured to be a controller that eliminates both the nonlinearity and dynamic behavior of the system. The Narma-L2 neurocontroller computes the control effort based on reference position and the actual position and its past value. Once the system eliminates the nonlinearity and dynamic behavior, the closed loop system becomes implicit algebraic relation between the reference position and the actual position. This means that the actual position do follow the reference position in real time. Normally, there is a time delay between the control effort and teh reference position in the calculation, i.e., the current control effort controls the actual position to match the reference position in the future time step.
In the first experiment, the Narma-L2 neurocontroller is used to control the water tank system that its cross section varies. The Narma-L2 nuerocontroller cannot eliminate the dynamic efficiently in this case. The remedy is that the predefine dynamics is installed back to the system such that the closed loop dynamics is as defined. The Narma-L2 neurocontroller combined with predefined dynamic is able to stabilize the system and also control the system follow a desire trajectory.
In the second experiment, the Narma-L2 neurocontroller is used to control the pendulum system. In this case, the Narma-L2 neurocontroller is able to elimnate nonlinearity and dynamic of the system, and thus, able to perfectly control the system to follow a smooth reference trajectory that is generated in real time using input device.