Transient DC motor performance

Kt_spec = 13.7; % oz-in/A ... torque constant from spec
Kv_spec = 10.2; % V/krpm ... voltage constant from spec
Tmax_spec = 2.82; % N-m ... max (stall) torque from spec
Omax_spec = 628; % rad/s ... max speed (no load) from spec 
N_oz = 0.278013851; % N/oz
m_in = 0.0254; % m/in
Kt_si = Kt_spec*N_oz*m_in; % N-m/A
rads_krpm = 1e3*2*pi/60; % (rad/s)/krpm
Kv_si = Kv_spec/rads_krpm; % V/(rad/s)
d = 2.5*m_in; % m ... flywheel diameter
thick = 1*m_in; % m ... flywheel thickness
vol = pi*(d/2)^2*thick; % flywheel volume
rho = 8000; % kg/m^3 ... flywheel density (304 stainless)
m = rho*vol; % kg ... flywheel mass
Jf = 1/2*m*(d/2)^2; % kg-m^2 ... inertia of flywheel
Jr = 56.5e-6; % kg-m^2 ... inertia of rotor
J = Jf+Jr; % kg-m^2 ... total inertia
Bm = 16.9e-6; % N-m/s^2 ... motor damping coef
Bd = 20e-6; % N-m/s^2 ... bearing damping coef
B = Bm + Bd; % N-m/s^2 ... total damping coef
R = 1.6; % Ohm ... armature resistance
L = 4.1e-3; % H ... armature inductance
TF = Kv_si; % N-m/A ... trans ratio/motor constant

a = [-B/J,TF/J;-TF/L,-R/L];
b = [0;1/L];
c = [1,0;-B,TF;-TF,-R;0,1;1,0;B,0;...
    0,R;0,1;TF,0;0,1;1,0;0,-TF;0,0;0,1];
d = [0; 0; 1; 0; 0; 0; 0; 0; 0; 0; 0; 0; 1; 0];
sys = ss(a,b,c,d);