BONNEY LAKE, Wash. – When an autonomous floor scrubber was rolled out in Walmart's Bonney Lake store last month, shoppers mistook the teal blue scrubber zipping down the aisles for a runaway machine.

"Some customers are a little freaked out," store manager David Klein said.

The Auto-C robot has relieved his employees of several hours of cleaning every evening, and has allowed him to avoid hiring another maintenance worker on the previously understaffed team.

The 4-foot-tall scrubber, which resembles a riding lawn mower but is considerably quieter, uses sensors to scan its environment and to avoid people or objects in its way. San Diego-based Brain Corp. makes the Auto-C robot's operating system.

At Walmart, the automated machines are just part of a push to bring this pioneer of big-box discounting into the future of brick-and-mortar retail, with implications for its workforce that are still unknown.

Last month the retail giant said it plans to spend $36 million on the remodeling of seven Washington stores, as well as the deployment of autonomous floor scrubbers, dozens of FAST unloaders akin to smart conveyor belts, and 16-foot-tall vending machines called pickup towers that dispense products ordered online.

Rivals such as Kroger and Seattle-based Amazon — which acquired Whole Foods in 2017 and launched a still-small chain of cashierless convenience stores called Amazon Go — have pushed Walmart to compete for customers by rolling out automated technology that offers convenience while keeping prices low. Meanwhile, the low unemployment rate and low corporate tax rate has spurred it to raise wages, increasing the allure of automation.

Artificial intelligence technology also allows the machine to map the layout of the store during a training ride and to continuously adapt to its surroundings, according to Brain Corp. But the machine occasionally needs help from humans, so it has a seat that is cordoned off by yellow straps in case the robot runs into an obstacle it can't outmaneuver and a Walmart worker needs to put it into manual mode.

At rest in the backroom of Walmart, the new autonomous floor scrubber stands near three manual ones that have been retired, their surfaces speckled with dirt and hoses haphazardly strewn about the handles. Klein said he plans to sell them.

Nearby, a conveyor belt churns as it scans boxes of items coming off a truck. It spots the product codes and separates the items into piles for workers to quickly restock shelves.

No employees have lost hours or changed positions in the past four months due to the rollout of new technology, Klein said. Other aspects of Walmart's online push have meant hiring: Thirteen workers have been hired at the Bonney Lake location.

According to a report by research firm CB Insights, "as the lines between physical and digital retail continue to blur," retailers are increasingly experimenting with automated technology and using stores to fulfill digital orders. For workers, said labor law professor Charlotte Garden of Seattle University's School of Law, the question is whether the expanded automation will mean they are redirected to other tasks or cut.

Klein said the innovations are making employees' jobs easier and increasing revenue. The FAST unloader has increased the availability of items on shelves by 2%, which he estimates has resulted in the store gaining $1,000 to $2,000 a day in sales.

Despite the new unloading technology, the Bonney Lake location has actually added 200 additional hours to the afternoon and evening stocking team shift since January as the company pivots toward constantly replenishing the shelves, Klein said. Previously, employees struggled to restock the depleted shelves during the day.

But it actually takes employees longer to unpack the trucks with the automated machine than it did during the days of manual unloading, he said. "The goal of this is not to unload faster," Klein said as a case of popcorn whirled past on the conveyor belt. "[It's] to get product to the floor faster."