eng Science and Education Publishing Journal of Automation and Control 2372-3041 2017-12-13 5 2 50 53 10.12691/automation-5-2-4 AUTOMATION2017524 article Alexander Gmiterko 1 Ľubica Miková 1 Ivan Virgala 1 Tomáš Lipták 1 Michal Kelemen michal.kelemen@tuke.sk 1 Department of Mechatronics, Technical University of Kosice, Faculty of Mechanical Engineering, Kosice, Slovak Republic Paper deals with friction difference principle, which is used as basic principle of robot locomotion. Piezoactuator is used as driving unit for locomotion. Structure of robot is described and also steady state velocity is derived. http://pubs.sciepub.com/automation/5/2/4/automation-5-2-4.pdf friction difference pipe locomotion piezoactuator