Travelling capsule with two drive mechanisms

A capsule robot, particularly for traversing the gastrointestinal tract, has two systems of propulsion: an inertial mass drive and driven legs. The robot comprises a housing closed by two end caps, enclosing a pair of linear actuators and first and second sets of legs. The actuators may be solenoids or linear motors and releasably couple to the legs via grippers which can be electromagnets. When the grippers are disengaged the actuators provide an inertial drive; when engaged, the actuators extend the legs through slots in the housing to engage with the wall
of the lumen through which the capsule is travelling. The two sets of legs may operate sequentially to drive the capsule forwards. Preferably, the end caps carry an LED light, camera, biopsy instrument and a power and control unit.