The field of Flapping Wing Micro Aerial Vehicles (FWMAVs) or commonly known as Ornithopters have seen a tremendous amount of research based upon an argument that they are more efficient than the traditional stationary wing or the rotary wing flight at smaller scales. Ornithopters emulate the natural flapping wing motion of birds and insects resulting in the flight. The presented work deals with the design and prototyping of the novel flapping wing mechanism for the Ornithopter in conjunction with the development of sophisticated system which can measure the flight parameters such as lift and thrust forces.
Intensive design iteration was carried out by varying the length of the linkages and their hinge positions in order to optimize the mechanism. All these kinematic analysis was aimed towards achieving higher flapping angle which can theoretically generate higher lift and thrust values. The optimized mechanism was manufactured and assembled. It was subjected further modifications based upon the operational feasibility and was installed on a chassis made up of the high density foam and wings were attached. Several tests such as the frequency measurement test, high speed photography test, wind tunnel test were performed in order to assess the aerodynamic characteristics and ensure the successful operation of the FWMAV. The final prototype was then enabled with BLDC motors and PWM transmitters to control the speed of the motor. The flight of the prototype was recorded.
In order to assess and enhance the flight characteristics of these Flapping wing MAVs, a sophisticated system is needed to measure its flight parameters accurately. The presented work also embodies the Design, Analysis and prototyping of a versatile and cost efficient test rig to measure the lift and thrust forces along with the flapping frequency of an ornithopter. A sensitive setup was developed based on NI Lab-view using Data Acquisition systems which has the ability to measure the lift and thrust forces with an accuracy of 0.1gram. The flight characteristics are measured with the aid of Strain gauge resistive type load cells and data acquisition system which is then refined by Lab-view software. The functional feasibility of the test rig was tested at room conditions as well as in a low speed wind tunnel for different angle of attacks (AOA) and various wind speeds using an ornithopter with 24 cm wing span and self-weight of 14 g. The test rig is designed in such a way that it can be used to test flight parameters for the Ornithopters of any wing span and load capacity. The wind tunnel test result shows that the maximum lift force, thrust force and flapping frequency generated by the used ornithopter is 41 g, 10 g and 16 Hz respectively.
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