The present invented mechanism comprises more than two (legs) with phase difference (like polygon-shape, ellipse-shape, and etc) between their rotation angles to produce pre-loading for improved adhesion. Two rigid plates covered with adhesives are attached to each phase difference wheel. Each plate connects to the wheels via a hinge embodying a torsional spring, which forces the plate back to its original position after each contact with surface. The phase difference wheels are made of elastic materials for application of controlled pre-loads at contact surfaces during locomotion. The difference between height and width of each wheel as well as the elastic properties of the materials determine the pre-load pressure applied during locomotion. The pre-load pressure is not strongly dependent on the orientation of locomotion. This enables locomotion in vertical, inclined and even upside-down orientation and also in the non-gravity environment.