Dynamic Reconfiguration Motion Analysis and Attitude Control of H-shaped Transformable Rotorcraft
Current tandem-type transformable rotorcrafts can realize the motion in a limited space,but some problems still exist in the stable flight control in the high-passability configuration,and also in the smooth control during the transforming process,caused by the time-varying center-of-gravity.To solve these problems,an H-shaped transformable tilt-rotor aircraft is proposed.The aircraft body is a segmented rotational structure,with both sides of arms spinning around the body.In this way,not only the tandem-type high-passability configuration is achieved,but also the adverse situation is avoided that the center-of-gravity locates outside the body.After the analyses on the aircraft flight control methods and the construction of motion models,a dynamic PID(proportional-integral-differential)control method and the corresponding allocation strategy are proposed based on motion characteristic values.The experimental verification is conducted on the motion attitude control response ability in the high-passability configuration,and the control stability during reconfiguration.Results of actual flight experiments show that,with the high-passability configuration,the maximum tracking error of the attitude angle in each axis is less than 4°,the tracking response time is less than 0.15 s,and the maximum passing-through size can be reduced to 44.2％compared to that of the normal flight configuration;in the reconfiguration process,attitude angle errors in each axis can be controlled within±2.3°.The mentioned flight in high-passability configuration reflects a good motion response characteristics,while the control response is generally smooth in the transition configuration.Overall,the aircraft has a good ability of the continuous traversal flight.
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