Preliminary Research On Morphing Wing Based On Avian Morphology

Since bionic morphing wing air vehicle has an extremely promising application prospect in themilitary and the civil field, it becomes a hot research spot at home and abroad. Compared to thefixed-wing and the rotary-wing air vehicle, bionic morphing wing air vehicle has the superiority,which will certainly occupy an important position in this field and have great significance indeveloping aerotechnics.Some related design problems about bionic morphing wing air vehicle has been studied in thispaper. The main work is as follows:Firstly, embarking from the avian flight theory, the flight modes of birds were analyzed afterabserving the characteristics of flapping, gliding and soaring. In order to have further understanding ofavian flight, the structure and function of the chest muscles and the wing were studied. The bionictheories were provided as the fundation for the designing of bionic morphing wing air vehicle.Difficulties still existed were discussed, and it came to a conclution that neither idiographic theory norexperiential formula could be found out, which reqires further exploration in bionic research.Secondly, pigeon was selected as the object for biomechanical study and its flying wing geometrywas inductived by observing and studying the external form. The flight structures and muscles wereobtained through the surgery experiment. Besides, the posture changes under flight were studiedthrough electrical stimulation and infrared thermal imaging. A morhing wing structure which has twojoints with four degrees of freedom was put forward based on the bionic experimental analysis. Theimpact of sweep and dihedral angles on aerodynamic performance was discussed which showed thatthe designed morphing wing can have a rather good simulation on avian structure and function.Thirdly, since birds have different geometry of wing shape in the process of flight simulation of theflapping and soaring were carried out respectively according to different kinds of birds. Selectingpigeon as the analysis sample of flapping, the geometry of wing was chosen in accordance with thelong distance flight racing champion pigeon. By controlling the joint angles and the stabilityrequirements, the vehicle shape change was gotten for different missions such as takeoff and landing,cruise, and steep descent, which were studied for aerodynamic analysis. Albatross was selected as theanalysis sample of gliding and soaring because of its excellent flying performance. Do as the processto the analysis of the pigeon, the configuration and the aerodynamic characteristics of morphing wingfor the three missions were gained. The optimization of the wing layout appearance came to greatmatch with avian postures. Finally, the SMA (Shape Memory Alloy) spring actuator of one DOF was designed to actuate thejoint to up/down or forward/backward. Heat training time, spring diameter and spring coil number ofSMA spring were studied to find out how manufacturing factors have an impact on its mechanicalproperties. The relationship between spring temperatures, mechanical properties and currentmagnitude was studied. A one joint wing was tested, so that the relationship between currentmagnitude and deflection angles was obtained.