Modeling And Nonlinear Control Of An Unmanned Tandem Helicopter

Unmanned tandem helicopter is an excellent aerial platform for reconnaissance, surveillance and search. Some important theoretical analysis and research results are as follows:(1) A brief review of unmanned helicopter and application of nonlinear control is given.(2) The dynamics and motion equations of unmanned tandem helicopter are established by mathematical modeling. And the system equations are transformed to affine nonlinear form.(3) Based on input-output feedback linearization, a controller is designed for tracking the output of unmanned tandem helicopter.(4) The non-minimum phase characteristics of unmanned tandem helicopter is analyzed. Dynamic extension of MIMO system and approximate linearization are combined to design the controller for output tracking of the unmanned tandem helicopter. The error of output tracking is proved to be bounded and stable.(5) For a class of nonlinear systems with unknown parameters, an output regulate method is proposed based on adaptive internal model. The vertical error dynamics is stabilized by the controller designed with the method. The lateral, longitudinal and attitude dynamics are stabilized based on small-gain input-to-state stable theory. The simulation results show that the output tracking of a class of vertical motion with known or unknown parameters can be achieved.(6) A kind of fuzzy PID controller is proposed based on incremental tuning and evolutionary strategies. Further, by using the developed fuzzy PID method, a practical controller is designed for unmanned tandem helicopter in position command. Simulations show that the proposed controller can improve system performances effectively.