Modelling and Oscillation Control of a Quadrotor with Cable-suspended Load

Abstract

A quadrotor with cable-suspended load is a type of aerial transport vehicle to carry a payload attached with a cable to underside of the quadrotor. It has potential applications requiring transporting goods quickly, such as search-and-rescue and logistics. One important requirement is that the controller should be able to safely move the quadrotor and suppress excessive load swing which can be dangerous. This work presents a modelling of this system and a PID position controller with feedforward input shaping to suppress load swing. The model is formulated with Euler-Lagrange equations. This model assumes offset between quadrotor centre-of-mass and suspension point of the cable, as such is able to capture double-pendulum-like behaviour of the real system. Simulations are done to validate the model and controller to suppress the load, swing and its robustness to varying percentages of modelling errors.