function   r_feedback


    h0 = 500;
    gamma0 = 0;
    v0 = 30:1:50;

    proj = slproject.getCurrentProject;
    wd = cd;
    cd([proj.RootFolder '/docs']);
    mdl = evalin('base', 'mdl_name');
    fcn = [mdl, '_an'];
    opts =  trimoptions(fcn);
    opts.v0_type = uint8(0);
    opts.max_alpha = 12/57.3;
    opts.min_alpha = -4/57.3;
    opts.max_de = 25/57.3;
    opts.min_de = -25/57.3;
    opts.max_da = 25/57.3;
    opts.min_da = -25/57.3;
    opts.max_dr = 25/57.3;
    opts.min_dr = -25/57.3;
    opts.max_throttle = 1;
    opts.throttle = 0.8;
    opts.TrimOptions.OptimizationOptions.Display = 'iter';
    opts.TrimOptions.DisplayReport = 'on';
    
    load_system(fcn);
    mdlWks = get_param(fcn,'ModelWorkspace');
    assignin(mdlWks,'mass0',360);
    
    h1 = figure();
    h2 = figure();
    for v =v0
        [success,opts1,op_point] = trimLon( opts, h0, v, gamma0 );
        if success
            opts = opts1;
            [~,Glat] = linfdm(opts.fcn,op_point);            
            figure(h1);
            [~,p,~] = zpkdata(Glat);
            Glat1 = zpk([],p{1,1},1);
            pzmap(Glat1);
            set(gca,'fontsize',10);
            xlabel('Real');
            ylabel('Imag');
            grid on;
            hold on ;
            ev = eig(Glat1);
            damp(ev);
            
            
            Glat_f = feedback(Glat, [0 0 0 0;0 0 -0.25*tf([1 0],[1 1]) 0]);
            figure(h2);
            [~,p,~] = zpkdata(Glat_f);
            Glatf = zpk([],p{1,1}([1:5]),1);
            pzmap(Glatf);
            set(gca,'fontsize',10);
            xlabel('Real');
            ylabel('Imag');
            grid on;
            hold on ;
            ev = eig(Glatf);
            damp(ev);
            
        end
    
    
    end
    cd(wd);
end