Modeling, control and stabilization analysis on a two-link active tumbler system

Tumbler system is a self-stabilized platform and its mechanical structure and premium stability properties can be used for designing coaxial helicopters without using stabilizer bar or flyer bar. The advantage of adopting a tumbler structure in coaxial helicopters is that it will replace traditional stabilizer bar or flyer bar to greatly stabilize flying attitude as well to reduce the structure complexity and volume size induced by stabilizer bars or flyer bars. In this paper, we start to study the nonlinear dynamic model of a two-link tumble system with a half circle shape at the bottom that will be extended to use in the design of a coaxial helicopter without using stabilizer bar. Based on the established model, magnitude-frequency characteristics and excited response are numerically simulated and evaluated. The PID controller is then designed for the tumbler system and dynamic responses of the controlled system are then extensively studied through simulations.