Abstract: A load-handling device for lifting and moving containers stacked in stacks in a storage structure, the storage structure including, above the stacks of containers, a first set of tracks extending in a first direction and a second set of tracks extending in a second direction which is transverse to the first direction, the load-handling device being configured to move on the tracks above the stacks, the load-handling device including at least one wheel which is provided by a combined wheel and wheel-control unit having the at least one wheel and a controller configured to control rotation of the at least one wheel.

Abstract: A load-handling device is provided for lifting and moving containers stacked in stacks in a storage system. The load-handling device includes a body; a wheel assembly arranged to support the body; a container-lifting mechanism configured to lift a container into or out of the body; and a wheel-positioning mechanism with wheel-engaging functionality for selectively engaging either a first set of wheels of the wheel assembly with a first set of rails or tracks of the storage system, or a second set of wheels of the wheel assembly with a second set of rails or tracks of the storage system. A wheel-engaging device can include at least one non-vertically-orientated linear actuator and/or at least one eccentric-rotation-based wheel-engaging device.