Method for handling malfunctioning vehicles on a rail system and a storage and retrieval system using such a method

A method for handling malfunctioning vehicles on a rail system constituting part of a storage and retrieval system configured to store a plurality of stacks of storage containers, wherein the rail system comprises a first set of parallel rails arranged in a horizontal plane P and extending in a first direction X and a second set of parallel rails arranged in the horizontal plane P and extending in a second direction Y which is orthogonal to the first direction X, the first and second sets of rails forming a grid pattern in the horizontal plane P comprising a plurality of adjacent grid cells, each comprising a grid opening defined by a pair of adjacent rails of the first set of rails and a pair of adjacent rails of the second set of rails,

• wherein the storage and retrieval system comprises
• a plurality of remotely operated vehicles each configured to move laterally on the rail system and to lift the storage containers stacked in the stacks through the grid openings in the rail system using a lifting device, and
• a control system for monitoring and controlling wirelessly movements of the plurality of vehicles,
• wherein
• the control system forms by wireless data communication at least the following steps:
• A. registering an anomaly in an operational condition of a vehicle on the rail system,
• B. registering the vehicle with the anomalous operational condition as a malfunctioning vehicle,
• C. bringing the malfunctioning vehicle to a halt,
• D. registering a halt position of the malfunctioning vehicle relative to the supporting rail system,
• E. setting up a two-dimensional shutdown zone within the rail system into which the malfunctioning vehicle is halted,
• F. updating movement pattern of the plurality of remotely operated vehicles outside the two-dimensional shutdown zone such that entrance into the two-dimensional shutdown zone is avoided and
• G. dynamically rerouting any operating vehicle that is outside the shutdown zone to avoid physical impact with a service vehicle during transport of the service vehicle to the shutdown zone, and/or to avoid physical impact with an operator walking to the shutdown zone.