Abstract: A robotic assembly (20) is provided which is adapted to traverse the surface of a member (138) for inspection and/or work on or about the surface of the member (138). The preferred assembly (20) includes two or more robots (10a-10c) spaced about the body (138) with a tether assembly (140) interconnecting the robots (10a-10c) in order to hold the latter in tractive engagement with the surface of the body (138). Each of the robots (10a-10c) includes rotatable traction wheel assemblies (16) which are independently controllable through respective drive motors (86), as well as independently controllable takeup reels (98) for adjusting the tension of the tether assembly (140). Each robot (10a-10c) preferably includes an elongated body (12) having four corner-mounted wheel assemblies (16) pivotally secured thereto, and a carriage (14) pivotally coupled to the body for pivoting thereof independently of the wheel assemblies (16) and about an axis transverse to the wheel assembly pivot axes.