PSO based parameter estimation and PID controller tuning for 2-DOF nonlinear twin rotor MIMO system

The present paper proposes a control methodology for a nonlinear multi-input multi-output (MIMO) system that combines a stochastic optimisation and proportional-integral-differential (PID) control scheme. This methodology is demonstrated through a laboratory scale helicopter setup commonly known as the twin rotor MIMO system (TRMS). The objective is to design a stochastically optimal/near optimal control law that can simultaneously stabilise the TRMS with considerable cross-couplings and provide satisfactory tracking performance to reach a desired position. The proposed control methodology utilises two PID controllers independently employed for the two rotors of TRMS. A PSO based parameter estimation technique has been utilised in this paper to estimate the parameters of the nonlinear TRMS laboratory setup. The nonlinear TRMS model with estimated parameters is employed to tune the PID gains by means of PSO in an offline manner and then implemented in real-life experimentations. The proposed realisation of PID control strategy is implemented for both simulation and real-life experimentations and their results demonstrate the usefulness of the proposed methodology.