In this paper, research was done to see how cable elasticity affects the behaviour of a quadrotor unmanned aerial vehicle (UAV) carrying a slung load. The research consists of two main steps.
In the first step, a non-linear model was derived using the Newton-Euler method. This resulted in the rotational and translational equations of motion of the system. The model was then simulated and validated using Simulink.
The second step was to design a controller for the UAV. This was done by finding the equilibrium for hovering, which is used as a basis for linearizing the non-linear system. The linearization resulted in the Jacobian matrix A and input matrix B; these were validated using the linmod function. While trying to design the LQR controller, the system was found to be not entirely controllable. It was tried to divide the problem into two with a cascaded controller. However, the same problems were experienced.