Control of Twin Rotor MIMO System Using Cross PID Control Technique

This paper deals with the 2-Degree of Freedom (DOF) control of a Twin Rotor MIMO System (TRMS). The TRMS is a Multiple Input Multiple Output (MIMO) system which is used as a laboratory setup for control experiments. It is a highly nonlinear system with a high order and significant cross coupling. A linearized mathematical model of TRMS which takes into account process noises (disturbances) and measurement noises in the system is considered. A Kalman Filter is designed for this system to obtain the noise free outputs from the noisy outputs of the system. It is controlled in two degrees of freedom using a cross PID (CPID) controller and also a conventional PID controller for comparison purpose. Both these controllers are tuned using three different metaheuristic optimization algorithms - Particle Swarm Optimization (PSO), Dynamic Spread Factor PSO (SFPSO) which is an improved version of the PSO and NMSPSO which is a hybrid algorithm of PSO with Nelder Mead Simplex (NMS) search method. Numerical simulations are performed to obtain the transient and steady state performance of the system for both the controllers. It is observed that the CPID controller tuned using NMSPSO gives the best performance compared to all the other cases.