A scanning system for use in inspecting or writing on a substrate minimizes vibrations by applying movement-actuating forces directly between a carriage and a countermass which are both free to move along parallel tracks. Forces for decelerating and accelerating the scanning carriage are preferably applied along a minor part of a length of movement of the carriage. The carriage is then isolated from forces applied parallel to the track while moving along a major part of its length of movement. As a result, the carriage travels smoothly with approximately uniform speed during it's operative pass, without suffering from vibrations introduced by direct closed-loop feedback control.