% Linearize airframe dynamics at each trim condition
G = linearize('csthl20_trim','csthl20_trim/HL20 Airframe',ops);
size(G)
8x5 array of state-space models.
Each model has 34 outputs, 9 inputs, and 12 states.
The linear equivalent of the "Controls Selector" block depends on the amount of elevator
deflection and should be computed for qbar_inv=1 (nominal dynamic pressure at
Mach=0.6). For convenience, also linearize this block at the 40 trim conditions.
CS = linearize('csthl20_trim','csthl20_trim/Controls Selector',ops);
% Zero out a/b and qbar_inv channels
CS = [CS(:,1:3) zeros(6,2)];
Linear Model Simplification
The linearized airframe models have 12 states:
xG = G.StateName
xG =
12x1 cell array
{'phi theta psi(1)'}
{'phi theta psi(2)'}
{'phi theta psi(3)'}
{'p,q,r(1)' }
{'p,q,r(2)' }
{'p,q,r(3)' }
{'ub,vb,wb(1)' }
{'ub,vb,wb(2)' }
{'ub,vb,wb(3)' }
{'xe,ye,ze(1)' }
{'xe,ye,ze(2)' }
{'xe,ye,ze(3)' }
Some states are not under the authority of the roll/pitch/yaw autopilot and other states
contribute little to the design of this autopilot. For control purposes, the most important
Trimming and Linearization of the HL-20 Airframe