Results of Short-Period Helicopter System Identification Using Output-Error and Hybrid Search-Gradient Optimization Algorithm

Table 5

Stability and control derivatives of the uncoupled short-period mode at 80 kt and 5,000 ft using only Levenberg-Marquadt approach.

Flight derivatives	Identified parameters	CRLB	Normalized CRLB (%)
$\frac{Z_w}{m}$ [1/s]	−0.7135	0.0155	2.2
$\frac{Z_q}{m}$ [m/s$\mathrm{\hspace{0.17em}\hspace{0.17em}}·\mathrm{\hspace{0.17em}\hspace{0.17em}}$rad]	0.0967	0.193	199.6
$\frac{M_w}{I_y}$ [rad/m$\mathrm{\hspace{0.17em}\hspace{0.17em}}·\mathrm{\hspace{0.17em}\hspace{0.17em}}$s,]	−0.0283	0.0007	2.5
$\frac{M_q}{I_y}$ [1/s]	−1.6821	0.0237	1.4
$\frac{Z_{\delta m}}{m}$ [m/s^2$\mathrm{\hspace{0.17em}\hspace{0.17em}}·\mathrm{\hspace{0.17em}\hspace{0.17em}}$cm]	−1.8328	0.0307	1.7
$\frac{M_{\delta m}}{I_y}$ [rad/s^2$\mathrm{\hspace{0.17em}\hspace{0.17em}}·\mathrm{\hspace{0.17em}\hspace{0.17em}}$cm]	0.2549	0.0023	0.9