Aircraft parameter estimation using output-error methods

Figures & data

Figure 1. Aileron (δ a) and rudder (δ r) inputs for the dutch-roll maneuver.

Figure 2. Cost function evolution with NM.

Figure 3. Cost function evolution with LM.

Table 1. Estimation of the nondimensional stability and control derivatives.

Coefficient	Initial values	NM method	LM method
CYβ	−0.0068	−0.0077	−0.0058
CLβ	−0.1861	−0.1821	−0.1514
CLP	−0.3562	−0.3272	−0.4718
CLr	−1.1700	1.6393	1.4942
CNβ	0.0678	0.0644	0.0415
CNP	0.0616	0.0538	−0.0275
CNr	−2.7110	−1.2157	−0.6765
	0.0068	0.0099	0.0052
	−0.0068	−0.0079	−0.0073
	−0.0001	−0.0032	−0.0029
	−0.0198	0.0623	0.0704
	0.0016	0.0023	−0.0405
	−0.2037	−0.1147	−0.1029

Table 2. RMS error for the outputs.

Variable	Nelder–Mead	Leverberg–Marquardt
β	0.0143	0.0131
p	0.0142	0.0132
r	0.0054	0.0045
φ	0.0205	0.0143
ay	0.0187	0.0143

Figure 4. Measured sideslip angle β(t) and estimated values by the NM method.

Figure 5. Measured roll angular velocity p(t) and estimated values by the NM method.

Figure 6. Measured yaw angular velocity r(t) and estimated values by the NM method.

Figure 7. Measured roll angle φ(t) and estimated values by the NM method.

Figure 8. Measured lateral acceleration ay (t) and estimated values by the NM method.

Figure 9. Measured sideslip angle β(t) and estimated values by the LM method.

Figure 10. Measured roll angular velocity p(t) and estimated values by the LM method.

Figure 11. Measured yaw angular velocity r(t) and estimated values by the LM method.

Figure 12. Measured roll angle φ(t) and estimated values by the LM method.

Figure 13. Measured lateral acceleration ay (t) and estimated values by the LM method.