Two-dimensional motions of a body containing internal moving masses

Movement of a body inside a resistive medium can be based on special vibrational motions of internal masses contained within this body. This principle of movement does not require any external devices such as wheels, legs, or tracks interacting with the outer environment; the system can be hermetic. This type of mobile systems sometimes called vibro-robots or capsubots can be useful for motions inside hazardous or vulnerable media and inside tubes. In the literature, one-dimensional motions of such systems were studied in various resistive media. In the paper, two-dimensional motions of a multibody mobile system carrying internal masses are analyzed in the presence of dry friction forces acting between the system and the horizontal plane. It is shown that, under certain conditions, this system can be brought from any initial position to the prescribed terminal position in the plane. The algorithm of motion is described and specified.