Gain Scheduling Control System Design Of A2-DOF Helicopter Model

As a common control object in the control field, the experimental helicoptersystem has many characteristics including nonlinearity, multi-variable coupling, andnatural instability and so on. When we control this system, many controlperformance problems can be studied, such as the follow-up, stabilizability,anti-interference and tracking. The system is the ideal platform of researchingcontrol algorithms and designing the control low, just because it has so manyfeatures. So usually it is very difficult to be described by exact mathematical model.In this paper, in order to study the internal properties of such systems, we built a2-DOF helicopter model in the laboratory on our own, and set the actual device as acontrol object, created the model and designed a gain scheduling output feedbackcontroller for the linear saturation system. A good combination of theory andpractice was achieved.Firstly, a deep analysis of the experimental system was conducted, after whichwe programmed the software based on RTX and MFC: a background runningprogram and a front control interface. The background running program controls theplant floor equipments. The user can control the system through the front controlinterface and save the running data.Secondly, in order to control the experimental system in-depth, we need toestablish the model of the system. In this paper, a nonlinear dynamic model wasestablished for the experimental system. We determined the relationship betweenthe voltage and the speed of the propeller and the relationship between the propellerspeed and lift. Then we got the final model of the actual system and the model wasvalidated in open-loop and close-loop with a PID controller.Thirdly, the theory and practice was combined in this paper. A PID controllerin theory was designed in this article and then the controller was used in the actualdevice. We validated the model’s correctness further by comparing the simulationresults with the response of the actual device, and also proved the effectiveness ofthe control law. But the PID controller can’t solve the actuator saturation of theexperimental system.Finally, we proposed and researched a gain scheduling output feedbackcontroller in order to deal with the actuator saturation problem in theory. Thecontroller was designed for saturated linear plants. It is a new kind of controllerwhich is in the form of LFT and can deal with the actuator saturation. And it isproved that the controller is effective through numerical simulation examples. A controller was designed for the linearized model. Then the controller was verified inpractical device after the simulation analysis. It has achieved good results insimulation and experiments.