| The tethered multi-rotor UAV system is a special kind of UAV in the field of Engineering application.It is mainly used in environmental monitoring,boundary detection,fire prevention and control,power transmission line monitoring and so on.The power generated by the cable ground mobile vehicle platform is supplied to the UAV,which solves the shortcoming of the traditional multi-rotor UAV in short duration and widens the use scenario of the UAV.However,at present,the domestic research results of this kind of UAV are few and have not achieved comparatively commercial value.At present,the domestic researchers mainly focus on the structural improvement of the device.There are few studies on the cable force and anti-jamming ability of the tethered UAV.At the same time,there are few studies on the application of tethered UAV in trajectory tracking and tracking efficiency improvement.Perform research on improvement.Therefore,this paper designs and analyses the tethered UAV platform from two aspects of dynamic model and trajectory tracking.By using the micro-element method,the force of the system is analyzed,and the dynamic model of tethered UAV is constructed.However,under the influence of unknown disturbance,the tethered UAV system has the problems of weak anti-jamming ability and low control accuracy.Therefore,this paper designs a controller based on backstepping sliding mode method to enable the tethered UAV system to track the preset trajectory more accurately.The main results of this study are as follows:1)The system realizes the power supply of the tethered system by using the power supply module,power conversion device and generator designed based on VICOR module.Then the ground mobile platform and the parts of the airplane are optimized,and the parameters are calculated.The design of the whole tethered UAV platform is completed.Through altitude control flight experiment,the stable operation of the equipment is proved.And the correctness of the dynamic model.2)Because the UAV is affected by the tethered cables,this paper uses the cross-flow principle to analyze the micro-segment of the cables,and solves the resistance of the cables under the influence of wind resistance,then uses the micro-element method to analyze the tension on the cables,calculates the tension caused by the cables on the UAV,and then based on the traditional Four-rotor UAV dynamics model.The cable forces acting on the UAV are taken into account and the model is improved to construct the dynamic model of the tethered UAV.3)Aiming at the characteristics of multi-rotor UAV,such as non-linearity and strong coupling,the back-stepping sliding mode method is used to design the corresponding control rate,and then the simulation of the preset trajectory tracking control is compared with the traditional back-stepping control method.The final results show the effectiveness of the method used in this paper.The research results in this paper have certain reference value for the trajectory tracking field of tethered UAV.To sum up,the Tethered UAV platform built in this paper can basically meet the test requirements,and the tracking method used by the platform has certain advantages,which can provide certain reference for the follow-up research of the Tethered UAV. |
