Encoders 010 - Encoder Applications - Encoders Used on Mobile Robots

My plan for these posts has been to focus on technical concepts in posts released on the 2nd Tuesday of the month and focus on real world applications in posts released on the 4th Tuesday of the month. I’ll continue that pattern with today’s post and discuss the exciting application of Encoders Used on Mobile Robots.

Years ago, the world of science fiction promised us we would all have robots in our future. With the help of books from authors like Isaac Asimov and movies like Star Wars, we envisioned robots which could move about freely, communicate with us, and help us in many ways (Star Wars); or sometimes scare the living daylights out of us (Terminator).

When the first robots arrived in real life a few decades ago, they were very different than we imagined. They didn’t walk on two legs, or even four legs. They were industrial robots, firmly mounted on a pedestal, and they stayed in one place as they drilled holes, welded or painted.

Industrial robots have been great for automating manufacturing tasks—but where are those mobile robots that move around on their own and interact with us in our daily lives? Where are the science fiction robots?

Guess what—they’re here! And they rely on encoders to help them function.

A company named Savioke (pronounced SAVVY-oak) has developed their Relay robot to help in hospitality, medical and other settings.

Savioke robots in action

The robot is shaped like a tall cylinder. It can move throughout a hotel or hospital, navigating on its own and even calling for an elevator when necessary. The robot has a lid on top that opens to reveal a cargo compartment. Items for delivery are placed inside the compartment, and the robot rolls away to make the delivery.

If a guest in a hotel forgets their toothbrush or razor, they can call the front desk and the Relay robot can deliver a replacement for the forgotten item within minutes.

In a hospital, a nurse can draw a blood sample, place it in the Relay’s cargo bin, and the robot will quickly deliver the sample to the lab for analysis.

Savioke uses encoders on the drive wheels, to accurately sense and measure the distance the robot travels. They also use an encoder on the lid, to sense the angle of the lid when it opens.

By the way, an interesting book called The Sprint Book has a section that discusses an experiment Savioke performed in a real hotel with actual guests. The company worried about the reaction unsuspecting humans might have when they opened their doors to discover a robot outside. The short answer: humans loved it! Many guests even took selfies with the robot. (Amazon’s free “Look Inside” preview of the book includes the section about the experiment.)

Mobile robots are becoming popular in retail stores, too. Badger Technologies developed a mobile robot to monitor hazards in grocery stores like spills. They’ve continued to add features; Badger’s latest model roams store aisles and scans shelves for depleted inventory, misplaced items or incorrect price tags. Badger uses encoders on the drives that move the robot.

“Yes,” you say, “those are mobile robots. But they move by rolling. Where are the exciting science fiction robots? The ones that walk on their own two – or four, or six – legs?”

Researchers have been busy developing the capabilities of robots that walk, sometimes called “legged robots.” It hasn’t always been easy. This video from a few years ago shows researchers at the University of Michigan, plagued by an intermittent failure of what turned out to be an encoder interface board.

Engineers have been making steady progress. Students at Stanford are developing their cute “Doggo” robot, which can walk on four legs and even do backflips.

Doggo the robot

You can see Doggo go through its moves in this video:

The students designed Doggo to be open source. Anybody can download the plans and build their own Doggo robot.

The link for the Bill of Material (BOM) shows that Doggo uses 8 encoders and 8 motors. Each motor has an encoder used to track the motor angle.

The trend in legged mobile robots seems to be for development to start in university research laboratories. As researchers gain knowledge, they start spinoff companies, and then eventually team up with industrial partners for broader sales distribution.

Agility Robotics, located in Albany, Oregon is a good example. One of the co-founders is also a professor at Oregon State University. Agility developed the “Cassie” robot, a two-legged walking robot.

Agility Robotics Cassie robot

Cassie’s legs utilize encoders on their joints, to measure the joint angle, as detailed in this video and technical paper from researchers at the University of Michigan.

Agility Robotics’ YouTube channel has more videos of Cassie walking, like this one.

Agility’s next step was to add a torso and arms – and probably more encoders – mounted above Cassie’s hips and legs. They call their new robot Digit, and just a few weeks ago Ford Motor Company announced that it was teaming up with Agility Robotics to explore integrating Digit with Ford’s self-driving vehicles. The plan is to deliver packages straight to a customer’s doorstep, with Digit stepping over obstacles and climbing staircases along the way.

Among many others, CNN reported the story about Ford and Agility, and explained that Amazon and FedEx are also developing delivery robots—but those are rolling robots, and can’t climb stairs as well as Digit. Those robots also require that the customer unload the package from the robot. Digit, on the other hand, can drop off the package all by itself if no one is home.

The trend is clear: those sci-fi robots you’ve been wondering about are definitely coming. They might already be in your grocery store, and before long you could get a text message saying that your pizza is at your front door—delivered by a mobile robot, every inch of its progress monitored by its encoders.

It is my goal to make this blog as informative, engaging and as accurate as possible. If you ever have some additional or contrary information, please contact me directly and I will be glad to make any appropriate corrections in a future post. Previous Post


Written by Steve Mathis
Director of Customer Relations & Marketing

"My goal at US Digital is to work with the excellent teams here to contribute to the success of our customers by eliminating pain points and making it easy for them to do business with us."