Development Of A Testbed For Measuring And Analyzing Magnus Effect

With high efficiency, low noise, safety, and vertical take-off and landing ability,ducted-fan UAV has become a hot spot in recent years. Air rudders are used in most ofUAVs as a part of control system, but it also has shortcomings such as different rubbersare mutual coupling and the system is nonlinear. Therefore, aided by The NationalNatural Science Foundation of China, our group has developed a ducted-fan UAV basedon the Magnus effect.This paper aims to provide reference data to optimize the control system of theUAV, with the following work done.Firstly, the principle of Magnus effect is studied, the surface pressure distributionof the rotating cylinder under the air stream is simulated with Fluent.The simulationdata is compared with calculated data, and the reasons for ineffiency are analyzed.Toimprove effiency, the simulation analysis of related factors for the Magnus forceformula is made. According to glof ball’s trajectory effected by its surfacecharacteristics, the assumption that the unsmooth surface will improve the efficiency ofMagnus effect is put forward and verfied by simulation.According to the characteristics of the UAV’s rubber actuator units and theprinciple of similar Reynolds number, a testbed to measure the Magnus force isdeveloped.The testbed constitute of airblow device, rotating cylinder device, datameasurement and collection device, and host computer system. Two rotating cylinderwill generate two forces that are equal but in opposite direction, so in the flat plane, atorque will be produced, and by measuring which, the force can be calculated.Finally, experiments under different wind speed and rotating speed are done.Curves showing how the force changes with different speeds are drawn to be comparedwith the theoretical value obviously. All the experimental data are used to optimize thecontrol system of the ducted fan UAV. Then a tether experiment is made to test andverify the feasibility of the rubber actuator units.Verified by experiment, the effect of the rubber actuator units meets the designrequirements. In hover state the flying direction can be adjusted easily. Magnus effectcan be taken advantage of as the rubber actuator instead of traditional air rubber.