6 River Systems is a US-based company that provides collaborative mobile robots for warehouses. Its flagship product is the autonomous warehouse robot, Chuck, which collaborates with warehouse workers on task guidance, picking and load carrying. 6 River's offering runs at about $250,000 for 8 robots in the first year, with annual maintenance costs of around $50,000 thereafter. (UPDATE: Shopify has completed acquisition of 6 River Systems on October 17, 2019.)
Visit 6 River's website at https://6river.com/.