Modeling And Control For A Quadrotor With Slung Payload

Quadrotor is a four-rotor-driven aircraft that has the ability of VTOL(vertical take-off and landing),with this structure it has a number of unique properties,possessing important military and civil values.Quadrotor with a slung payload can be utilized in many senarios,such as cargo delivery、removing dangers、geological survey and so on.Studies associated with modeling and control of this system is still not much,current modeling methods in terms of cable angles feedback are too complicated,so are the control algorithms.Based on conventional quadrotors,this paper simplified both modeling and control design of the quadrotor with slung payload system.The main contributions and innovations are as follows:(1)A review of quadrotor’s history,the state of art,hot areas and difficulties was presented.(2)Analysis of the basic structure and principles of the quadrotor was depicted,and then the dynamic model of quadrotor including the translational and rotational motion was derived;the establishment of attitude dynamics model was abtained through two different ways.(3)Starting from the classification of slung payload model,tethered model under different scenarios was introduced,exclusively followed by a review of helicopter with slung payload,control laws under multiple scenarios were clasified,in adition means to deal with a quadrotor with slung payload were analysed.(4)Dynamic model for a quadrotor with slung payload was derived and a modified algorithm was proposed.In traditional modeling,the expressions of cable angles feedback are obtained by solving Lagrangian equations which is tough and the solutions are complicated.Hence it is not easy to determine the state variables,making it difficult to design controllers.This paper proposed a new solving algorithm,which simplifies the dynamic equations of the system greatly and contributes to controlling it.(5)On the basis of the new model,a PD controller was put to a quadrotor with slung payload for the first time,realising height controlling and attitude controlling efficiently.Rresults from the MATLAB simulation shows that the designed PD controller can achieve that the control errors approach zero in a relatively short period of time,which means the controller can obtain effective flight controlling performance.