# Research on the Flight Performance of Biomimetic Moth Based on Flapping Function Control
## 4 Flight Experiment and Result Analysis of Biomimetic Flapping-Wing Aircraft
### Turning Test: Turning Based on Amplitude Difference of Left and Right Wings  
Two flight tests were carried out using the flight controller to input parameters, as shown in Table 11.  
In both groups of experiments, the flapping amplitude of the left wing is greater than that of the right wing, and the flapping-wing aircraft turns left, indicating that the flapping-wing aircraft will turn to the side with a larger flapping amplitude. When the amplitude difference is \(9^{\circ}\), the turning radius is larger, and when the amplitude difference is \(18^{\circ}\), the turning radius is smaller, indicating that the magnitude of the amplitude difference affects the turning performance of the flapping-wing aircraft, and the larger the amplitude difference, the tighter the turning radius. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Control Parameters** & **(a)** & **(b)** \\ \hline Flapping frequency & 4 Hz & 4 Hz \\ Mid-position angle & \(5^{\circ}\) & \(5^{\circ}\) \\ Left flapping-wing aircraft & \(58.5^{\circ}\) & \(63^{\circ}\) \\ Right flapping-wing aircraft & \(49.5^{\circ}\) & \(45^{\circ}\) \\ Amplitude difference & \(9^{\circ}\) & \(18^{\circ}\) \\ Initial pitch angle & \(10^{\circ}\) & \(10^{\circ}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Control parameter table of turning test. Figure 16: Results of Turning Test. (**a**) diagram with a \(9^{\circ}\) amplitude difference; (**b**) diagram with an \(18^{\circ}\) amplitude difference; (**c**) merged diagram of flight trajectories. The altitude of the flapping-wing aircraft decreases when turning, indicating that amplitude difference turning will affect the generation of lift to a certain extent. Before turning, the flapping-wing aircraft can be made to pitch backward and generate an upward trend, which can offset the downward trend caused by turning to a certain extent. In summary, creating a difference in the flapping amplitude of the left and right wings can make the flapping-wing aircraft turn, and the flapping-wing aircraft will turn to the side with a larger flapping amplitude. The larger the amplitude difference, the tighter the turning radius. This is consistent with the results of the simulation calculation, indicating that the simulation results are basically accurate. Flight Altitude Test: Impact of Change in Absolute Value of Mid-Position Angle on Flight Altitude of Flapping-Wing Aircraft  
Three flight tests were carried out using the flight controller to input parameters, as shown in Table 12.  
When the absolute value of the mid-position angle increases, the flight trajectory of the flapping-wing aircraft slopes downward and then becomes horizontal again, indicating that increasing the absolute value of the mid-position angle can make the flapping-wing aircraft pitch forward and dive, and it has almost none impact on its flight capability. The position distribution of the flapping-wing aircraft is compact and close over time, indicating \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Control Parameters** & **(a)** & **(b)** & **(c)** \\ \hline Flapping frequency & 4 Hz & 4 Hz & 4 Hz \\ Mid-position angle & 5\({}^{\circ}\) & 5\({}^{\circ}\)\(\rightarrow\)10\({}^{\circ}\) & 5\({}^{\circ}\)\(\rightarrow\)0\({}^{\circ}\) \\ Flapping-wing aircraft & 54\({}^{\circ}\) & 54\({}^{\circ}\) & 54\({}^{\circ}\) \\ Initial pitch angle & 10\({}^{\circ}\) & 10\({}^{\circ}\) & 10\({}^{\circ}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Control parameter table of flight altitude test. Figure 17: Results of Flight Altitude Test. (**a**) diagram when normal fight; (**b**) diagram when mid-position angle increases; (**c**) diagram when mid-position angle decreases; (**d**) merged diagram of flight trajectories. that the generated propulsive force is weak. In general, increasing the absolute value of the mid-position angle can make the flapping-wing aircraft fly lower.