Abstract: A self-propelled vehicle for use in performing work inside pipes of piping systems, for example, for cleaning or coating the inner surface of the pipe includes at least three traveling assemblies connected to the body of the vehicle by parallel link assemblies. The traveling assemblies are travaeled along the pipe inner surface to be worked on by the operation of a drive unit and transmissions while being pressed against the pipe inner surface by a collapsing assembly. During travel, a liquid can be sprayed onto the pipe inner surface by a nozzle which is rotated.