Your ‘const*t’ signal is a ramp function. Probably the easiest way to do what you want is to use the lsim function:
s = tf('s');
H = s/(s^2 + 1); % Arbitrary System
t = linspace(0,100); % Time Vector
Const = 4.2;
u = Const * t; % Ramp Function
figure
lsim(H, u, t); % System Response To Ramp
Make necessary changes to the ‘t’ vector and ‘Const’ to work with your code.
