Linearization of SimMechanics models

I'm trying to trim a 4 DoF SimMechanics model. I need all the velocities and accelerations zero at the equilibrium point, also I need to keep all the states at initial conditions. That means the goal of trimming is to find the input such that the initial states is an equilibrium. I know that there exist such an input.There are 16 states, and my code for trimming is

ix = [1;2;9;10]';     % Since this is 4Dof system, keep 4 states fixed    
y0 = [0 0]';                 % Output is the initial output
iy = [1 2]';                 % Keep outputs fixed to initial output

dx0 = zeros(16,1);    % Set initial guess velocities to zero
idx = [1;2;9;10];           % Keep two velocities/accelerations fixed to initial condition

u0 = [0 0 0]';                 % Initial guess value of input
iu = 3;                % Keep only 3rd input fixed (This is disturbance)

%%Trim the model
 [x,u,y,dx] = trim('Loader',x0,u0,y0,ix,iu,iy,dx0,idx,2);

The resulted trim point of this model does not give all zero states and zero velocities and accelerations. Does anyone have any idea what is wrong here? Is my understanding correct? I did not find a good documentation on how the trimming process works. Thanks in advance -Punit

Answer 1

[Guy Rouleau]

Try the function FINDOP from Simulink Control Design.

It is designed for trimming models and is more powerful than TRIM.

[N/A]

SimMechanics supports FINDOP, so this function is really the way to go if you have access to the Simulink Control Design toolbox.