Real time hybrid fuzzy-PID control of a twin rotor system

This paper presents the development and implementation of a real time hybrid fuzzy-PID control paradigm for an aerodynamic test rig, a twin rotor multi-input-multi-output system (TRMS) which resembles the dynamics of a helicopter in certain aspects. The TRMS can be perceived as a challenging control problem due to its high nonlinearity, the coupling effects between its two axes and the inaccessibility of some of its states and outputs for measurements. The objective of the controller is to move the beam of the TRMS to the desired positions accurately addressing these demanding attributes. The controllers are based on the accurate dynamic models for both vertical and horizontal movements of the system. A fuzzy controller is firstly designed according to the characteristics of the process and then improved with an integrator, in order to reduce the steady state error compared to a conventional fuzzy controller. The responses of the controllers are validated using various reference inputs. A comparative performance study between the developed hybrid fuzzy-PID control approach and the single PID based approach is also made in this investigation.