Call it R2-D2 without the attitude.

FedEx Corp. envisions a not-too-distant future in which it relies on Star Wars-style robots for more deliveries, as portrayed in a company video. Imagine a box-shaped bot that can roll out of a neighborhood pharmacy and drop off prescription medicine at a nearby house.

The courier is ready to begin testing a 4-foot, 2-inch tall delivery robot in Memphis, Tenn., and two other cities as early as this summer. The battery-powered bot travels at 10 miles an hour, has a range of eight miles and can navigate streets, sidewalks, curbs, potholes, dodge pedestrians and even take the steps up to a home's front door.

While airborne drone deliveries — and all the technological and regulatory hurdles they entail — are getting most of the attention these days, FedEx believes it has an option for same-day ground service that's ready to go. Six major retailers, including Walmart., Target, Walgreens and Lowe's, have signed on to try out the six-wheeled contraption, said Brie Carere, FedEx's marketing chief.

"Right now in the market, nobody does this effectively," Carere said. "This device is way more cost efficient than sending a full-sized truck or even a full-sized car. It's also safer and more environmentally friendly."

The demands of e-commerce shoppers are pushing retailers to compete for speedier delivery, which is driving up costs to hire drivers and buy and maintain vehicles while creating more traffic on busy city streets. Costs and congestion will only increase as internet purchases, which make up about 14 percent of overall retail sales, continue to surge.

FedEx developed its mobile robot with the help of Deka Research & Development Corp., the group founded by inventor Dean Kamen that produced the Segway scooter. The platform for the device is Deka's iBot, a motorized wheel chair that is capable of climbing stairs and has more than 10 million miles of operation by users.

The FedEx robot will be able to carry packages as heavy as 100 pounds and will use machine learning to calculate the optimal route to a delivery destination. It's equipped with sensors and cameras to help it find its way and avoid obstacles. The robot will signal to pedestrians, cyclists or motorists when it's turning or stopping. If needed, it can even talk to people it encounters via speakers operated by a FedEx employee who will monitor the robots remotely, Carere said.

The device weighs about 200 pounds and can run two hours on a single charge. FedEx declined to discuss the price of the robot, the delivery cost, or the potential volume the bots could handle. The company hasn't announced the two other test cities yet.