Control of Quadcopter with Suspended Load by Internal Model Control and Input Shaping for Reducing the Load Oscillation

In this paper, the performance of the internal model controller on the behavior of suspended load quadcopter is investigated, where due to the inherent instabilities of the quadcopter and the hazards and instabilities that may be caused by suspended mass oscillation, the use of a method to stabilize and ensure the safe performance of the system is important and necessary. The proposed controller in this paper is responsible for controlling the attitude and position of the quadcopter and maintaining the overall stability of the system as well as the robustness against internal disturbances and suspended load swing. Internal model control is a robust model-based controller that directly uses the nominal system model and its approximate inverse in its synthesis. When the inverse of nominal model is improper, a filter is also used in the design. The compensator, used to control the system, employs only one control parameter. This is the reason of the controller synthesis simplicity as well. The required nominal model, used in internal model controller structure, is obtained via linear parameter varying modeling method. Furthermore, in order to reduce the suspended load oscillation, the input shaping technique is used, where the simulation results show the appropriate performance of the system to maintain attitude and position of the quadcopter and suspended load swing reduction during the path tracking.