Robot follows a path near an obstacle without colliding
Robot Motion Planning is an important topic in Computational Geometry. There have been a lot of research in this field.

Here are some pointers that might help you:

Slide: http://www.mpi-inf.mpg.de/departments/d1/teaching/ss10/Seminar_CGGC/Slides/06_Bazhenova_RMP.pdf

Slide: http://www.cs.cmu.edu/afs/cs/academic/class/15381-s07/www/slides/020807motion.pdf

Book: http://books.google.com/books?hl=en&amp;lr=&amp;id=_VRM_sczrKgC&amp;oi=fnd&amp;pg=PR11&amp;dq=robot+motion+planning&amp;ots=zFkR07oxBJ&amp;sig=efsVfaDPAlhKgxZwClKS136moCI#v=onepage&amp;q=robot%20motion%20planning&amp;f=false

Website: http://correll.cs.colorado.edu/?p=965