Your objective function does not allow the ga function to adjust any of the parameters of your model. (I would have expected this to have thrown an error.)
It ideally should be something like this:
object = @(b) sum((y_m(b)-y).^2);
where your ‘y_m’ model is a function of ‘b’ (or whatever you want to call your parameter vector). You can pass other parameters to it as well, if necessary. See the documentation on Passing Extra Parameters (link).
