Getting the error “Undefined function 'ilaplace' for input arguments of type 'double'.” when trying to laplace a heaviside function in MATLAB

I am trying to solve for the output of a system by taking the laplace transform of a function with a heaviside function. In my code when I have

v = 0.05715*(2*pi/td)*sin(2*pi/td*t)*(heaviside(t))

it works. However, when I change it to

v = 0.05715*(2*pi/td)*sin(2*pi/td*t)*(heaviside(t)-heaviside(t-td))

I can't seem to graph anything because the input V ends up having complex numbers in it and gives the error Undefined function 'ilaplace' for input arguments of type 'double'. Anyone know how to fix this?

% Constants and variables
syms s t
k1 = 12500;
k2 = 87320;
m1 = 84;
m2 = 23;
b1 = 1000;
b2 = 708.6;
td = 0.6652;
pi = 3.1416;

% State space matrices
A = [-b1/m1 b1/m1 1/m1 0; b1/m2 -(b1+b2)/m2 -1/m2 1/m2; -k1 k1 0 0; 0 -k2 0 0];
B = [0; b2/m2; 0; k2];
C = [-b1/m1 b1/m1 1/m1 0];
D = 0
I = [1 0 0 0; 0 1 0 0; 0 0 1 0; 0 0 0 1];

v = 0.05715*(2*pi/td)*sin(2*pi/td*t)*(heaviside(t)-heaviside(t-td));    % input in t domain
V = laplace(v,s)    % input in s domain
G = (C*inv(s*I-A)*B*.68 + D)*V % output in s domain

V1 = vpa(ilaplace(G, s, t), 3) % output in t domain
ezplot(V1,[0,1])