Walmart just patented a system based on mini-robots that can control shopping carts, as well as complete a long list of duties once reserved for human employees. Last week, Walmart was granted a patent for a new system that allows shopping carts to drive themselves, untouched by customers and employees. However, the system goes far beyond self-driving carts, with details on automated devices that can do much of the work a human employees would do.

According to the patent, “motorized transport units” are tools that attach to shopping carts, allowing the carts to drive freely around the store, be summoned to customers, and move safely into docks instead of clogging up parking lots. The system uses a combination of sensors, video cameras, a wireless network, and a central computer.

“Walmart was able to revolutionize retail using technology to better serve customers,” Walmart spokesperson Lorenzo Lopez told Business Insider. “And as the retail landscape continues to evolve, we want to be able to serve customers when and how they want to shop. That means testing new and innovative ways to serve the customer, which we’ve done through different initiatives like our grocery pickup service.”

While the patent describes the motorized unit’s role as enhancing a shopping experience and assisting customers or employees, the new tech could be bad news for Walmart employees. Walmart has come under fire for a number of issues with staffing and employees in recent months.

More than 200 violent crimes have been committed so far this year at Walmart locations across the US, with Bloomberg arguing that the rise in crime is linked to the retailer understaffing stores. Cost-cutting policies that started in the early 2000s resulted in a drop in store quality, while the loss of greeters and the rise of self-checkout scanners made shoplifting and other illegal activities easier to engage in without employees noticing.

The patent’s authors argue that the new, tech-heavy system could improve customers’ in-store experience and solve problems that Walmart employees cannot.