US Patent 9738449 Inventory holder load detection and/or stabilization

An inventory system includes an inventory holder that may be moved by a mobile drive unit. The inventory holder may hold inventory items. The mobile drive unit may move in a manner for facilitating a shift of position of at least one inventory item relative to the inventory holder. Such movement may be accomplished, for example, by accelerating, decelerating, turning while driving, spinning, dropping the inventory holder, or by causing at least one of the mobile drive unit or the inventory holder to at least one of interact with or engage an obstacle such as a bump over which the mobile drive unit drives, a bar positioned above a floor on which the mobile drive unit drives, a wall, another mobile drive unit, or another inventory holder.