Because you gave no MWE I had to guess. I used paper=A6 to simulate your column.
\documentclass[paper=A6]{scrartcl}
\usepackage[hyphens]{url}
\makeatletter
\g@addto@macro{\UrlBreaks}{\UrlOrds\do\r\do\u\do\b\do\i}
\makeatother
\usepackage{showframe} % to show typing area and margins
\begin{document}
text
\url{http://people.mech.kuleuven.be/~bruyninc/tmp/HermanBruyninckx-robotics.pdf}
\end{document}
With the line \g@addto@macro{\UrlBreaks}{\UrlOrds\do\r\do\u\do\b\do\i} I defined that an url can be broken at the letters r, u, b or i. You can add more if you need. The syntax is \do\ followed with the letter were the url can be broken.
Result:

For example test with adding \do\t to allow breaking at t.
I just found that question Forcing linebreaks in \url is a possible duplicate (see answer of Herbert Voss).
\usepackage{url}and then\url{http://people.mech.kuleuven.be/~bruyninc/tmp/HermanBruyninckx-robotics.pdf}do the trick? – yo' Oct 25 '15 at 18:57~is cutting the URL to only the first half? I.e. tohttp://people.mech.kuleuven.be/. How do I fix this? – space_voyager Oct 25 '15 at 19:03