Double 2 Review: Trying Stuff You Maybe Shouldn't With a Telepresence Robot

We find out how well a telepresence robot can visit the zoo and play golf at the beach

15 min read

Evan Ackerman is IEEE Spectrum’s robotics editor.

Double 2 telepresence robot at the Oregon Zoo
What, never seen a robot visiting the zoo before?
Photo: Colin Ackerman

At CES in January, Double Robotics announced the Double 2, a major upgrade to their super skinny telepresence platform that features better stability and turbo speed. It looked cool, but we didn’t get super excited about it, because like most telepresence robots, it’s designed to work very well in some very specific, usually business or education-focused environments. We’ve tested these things out before, and once you get past some hiccups and quirks, they generally do what they’re supposed to do, which is provide you with a mobile embodied presence somewhere that you’re not.

When Double Robotics asked us if we wanted to test out a Double 2, we said sure, with two conditions: 1. it had to come with an LTE cellular data connection, allowing us to use the robot free of Wi-Fi; and 2. we could take it anywhere we wanted. To their credit, the company didn’t even hesitate, and they shipped us a brand new Double 2, along with the camera and audio kit accessories and charging dock. Cool, now we can see what this robot can do—and maybe what it can’t.

Where are we taking it? Not some business or education environment. Our Double is going to the zoo.

To be clear, we aren’t trying to intentionally abuse the Double 2. We’re not going to deliberately run it into stuff, or drive down stairs, or take it swimming, or anything like that. Our goal is to see what the robot is capable of while knowingly operating it outside of the environments and infrastructure that it’s intended to be most effective in. The Double 2 is designed to operate indoors, in offices and workspaces and classrooms where you have strong and reliable Wi-Fi. And it’s not unique in these requirements: it’s where all telepresence robots do best. If you want to use a Double for business, then great, go right ahead. Personally, I’m less interested in business use cases, and for this review I wanted to know what this robot can do for me in different non-structured environments (aka the real world).

So it’s important to read this review in context: I’ll be trying to use this robot outside when it’s meant for indoor use. I’ll be using it extensively on weak LTE when it’s meant for strong Wi-Fi. Double is not really engineered or intended to do what I’m going to ask it to do, and from that perspective, this review will be rather punishing for the poor robot. I let Double (the company) know all of this beforehand, and they placed absolutely no restrictions on what I could try. They were probably confident that the robot, even if it couldn’t provide an ideal experience, would still perform reasonably well. So as you read about how this went, keep in mind that I’m doing the equivalent of trying to chop up a potato with a spatula. And with that metaphor for you to puzzle out, let’s get to it.

Assembling My Robot Body

Double 2 telepresence robotThe robot requires an iPad Air 2 or iPad Pro (not included), and comes with a 720p HD camera, audio kit, and charging dock.Image: Double Robotics

Reviewing a telepresence robot is a bit different than most of the reviews that we do, because the whole point of this robot is that it spends as much time as possible very far away from you. I live in Bethesda, Md., just outside of Washington, D.C. I asked Double to send a review unit to my family in Portland, Ore., approximately 4,300 kilometers away. That means I have not personally touched, or even seen, the robot I’m going to spend this article talking about, but here’s a picture [right] showing what it looks like.

For the setup process, I enlisted my brother, who took care of the whole thing in about 5 minutes. He said it was mostly just attaching things to places where they were obviously supposed to be attached. This includes attaching an iPad to the Double robot itself. It’s important to understand that for Double to work, you have to have your own iPad, which acts as the screen, functions as at least part of the brain, and provides wireless connectivity. In our case, Double supplied us with an iPad Air 2 that included LTE, so we didn’t have to worry about that.

I logged into the robot through a slick web interface on Google Chrome, and:

Double 2 telepresence robot screenshot

Oh hi Kallie! Good, it works.

Teleporting Myself Across the U.S.

You drive Double through the web interface, and it works pretty well. Most of what you see is the picture coming from the main camera on top of the robot. Inset on the lower left is the view from a downward-looking secondary camera that shows you the area around the base and the ground directly in front of you (you can click on it to enlarge it, as shown below). There’s also a small window on the right that displays the view from your webcam, which is what everyone on the other end is seeing.

Double 2 telepresence robot screenshot

Initially, the driving experience takes a bit of practice. The robot moves slowly and carefully (to start off with, at any rate), and it’s very forgiving, but getting accustomed to the lag is a bit of a challenge. Lag, or latency, refers to the amount of time it takes for you to push a button on your keyboard to send a command to the robot, have that command relayed from your computer to the robot, have the robot to execute that command, and then for the result to make its way back from the robot to your computer. Anyone who plays real-time online games will be familiar with this principle, but there’s an additional layer here of a physical robot that needs to engage motors. The upshot is that it takes several hundred milliseconds for a “go forward” command that you send to the robot to show up on your screen as the robot moving forward.

Hundreds of milliseconds doesn’t sound like a lot, and strictly speaking it isn’t a lot, but it makes driving Double 2 (or any robot, for that matter) require a bit of getting used to. You have to account for the lag when you drive by planning ahead, and turning or stopping on your end before you need the robot to turn or stop on its end. This is exacerbated if you have a poor connection, but don’t worry, we’ll be talking lots more about that.

According to a speed test that day, my brother’s internet connection was something like 60 Mbps download, but only 3 Mbps upload. This kind of asymmetrical connection is typical, because most people download lots of stuff and don’t upload lots of stuff, so many internet providers skew the connections towards downloads. Most cellular data connections do this, too. For a telepresence robot, a good download speed and not-as-good upload speed mean that the people interacting with the robot are likely going to have a much better experience than the robot operator. That was true in my case, with everyone talking with my Double getting flawless audio and video of my noggin. I guess this is the best way for it to work, since as the user, you’re much more likely to be forgiving of questionable quality than someone who you’re trying to talk to who knows nothing about robots and bandwidth and asymmetrical connections.

With that meager 3 Mbps up, the quality of my experience driving around my brother’s house on his Wi-Fi was tolerable. Decent, I guess. I could talk to him face to face-ish, follow him around, and avoid running over the dog. Everything was dark and a bit blocky, but not too bad, and my brother said that the image he was seeing on the iPad was good quality, and that I was easy to see and understand, although he stopped short of actually saying that I “looked good.”

Robo-Walking the Dog

With the robot up and running, we decided to take the dog for a walk. Here’s what Double says about taking the robot outside:

Your Double is intended for indoor use. Hard, smooth surfaces are the perfect environment for your Double. We recommend that you avoid driving your robot over thick, shaggy carpet, rough surfaces, or deep thresholds. This is mostly to avoid damage to your Double’s wheels. 

They aren’t kidding: there is no suspension, very little ground clearance, and the wheels on the robot are covered in thin strips of rubber that offer good traction but no cushioning. This will not be a fun experience for the robot.

The other problem is, of course, that my brother’s Wi-Fi isn’t going to work very far from his house, which means that we’re going to be on LTE. This is what Double says about running the robot over a cellular connection:

Double works great over cellular/4G/LTE, as long as you have decent reception. It’s common to use a cellular connection in crowded venues, like conferences and trade shows, where Wi-Fi sometimes doesn’t work very well.

“Works great,” you say? Great! 

We headed outside into the street, and the iPad automatically switched from Wi-Fi to LTE, disconnecting me in the process. When this happens, incidentally, the Double will sit still and wait for its user to come back. I was able to reconnect immediately, and was greeted by this:

Double 2 telepresence robot screenshot

Yeah, it’s bad. This is what driving a telepresence robot looks like on one or two bars of LTE. The problem was compounded by the road: some of the older neighborhoods in Portland have roads with a charming patchwork of different compositions and vintages of cement, which Double did not handle well at all. Still, the robot never fell over (props for that), but there was a lot of starting and stopping, and it was impossible to drive fast enough to keep up with someone walking a dog, which was frustrating for everyone involved (especially the dog). Using Double 2’s new “turbo mode,” you can keep up with a person walking, but you need a good connection for it to work safely. After about 5 minutes of trying not to run into stuff when I could barely see, my brother got fed up with me, and carried the robot back home.

The robot never fell over (props for that), but there was a lot of starting and stopping, and it was impossible to drive fast enough to keep up with someone walking a dog, which was frustrating for everyone involved (especially the dog).

Part of what made this attempt frustrating for us was that the asymmetric nature of the LTE connection made it so that my brother was getting relatively decent picture and audio from me, while I was getting, well, you saw the picture above. There was really no way for him to know what I was dealing with, so he just thought I was being overly cautious. I wasn’t.

Let’s Go to the Zoo!

It was immediately obvious that the only way we were going to get Double to behave itself outside was to find somewhere with a strong and reliable LTE connection, along with very smooth surfaces to drive on. I decided that we’d go visit the Oregon Zoo, which is at the top of a hill, minutes from downtown Portland.

Double 2 telepresence robot screenshot

I didn’t bother to ask anyone at the zoo for permission or anything; my brother texted me after he’d parked and unloaded the Double 2, and I logged into the robot right there in the parking lot. My brother walked off to buy his ticket, and I just kind of hung out there awkwardly for a while, exchanging a few words with people walking past.

Double 2 telepresence robot at Oregon Zoo screenshot

It was a little bit unnerving to think about the fact that any one of those people could have picked “me” up and run off, and I wouldn’t be able to do anything to stop them. The way I dealt with this was by not thinking about it at all, and just assuming that everyone would be friendly. And since this was Oregon, they were.

Double 2 telepresence robot at Oregon Zoo screenshot

I introduced myself to the people taking tickets, and rolled on in for free. They can’t charge me if I’m not technically at the zoo, right? For the record, I don’t feel bad about doing this because in high school I spent about a bajillion hours volunteering in the zoo’s birds of prey show, so I figure they owe me.

The LTE at the zoo was much, much better than outside my brother’s house. It was still not nearly as good as any sort of Wi-Fi, but it was easily good enough that I could drive around with confidence. The Oregon Zoo is on a hill, but it’s all wheelchair accessible, which means it’s also Double 2 accessible, with nice big smooth paths and ramps everywhere.

While I wasn’t worried about people stealing the robot, having my brother around as a chaperone was valuable, since he made sure that I didn’t accidentally get myself into trouble. More importantly, he was there to explain to people just what the heck I was, answering questions about the robot from people who didn’t immediately realize they could just talk to me.

Double 2 telepresence robot at Oregon Zoo screenshot

It was an amazing amount of fun to interact with people, explaining what the robot was, and that yes, I really was controlling it from Maryland. Kids in particular were fascinated, and the Double 2 was, arguably, more popular than the animals. I mean, everyone has seen animals before, but a robot is something new.

“What IS that?”
“It’s a robot!”
“There’s a face on it!”
“Is there a person in there?”
“That’s so cool!”

Many adults were just as fascinated as the kids, although some didn’t seem that enthusiastic about a possible robot surrogate future. “It’s for people who want to go to the zoo without leaving their house,” I overheard a guy telling a small child.

Driving over LTE, even halfway decent LTE, is a serious challenge. While moving, I was occasionally experiencing severely degraded video with latency that varied from a few tenths of a second to a full second, and sometimes the video and audio froze completely for 5 or 10 seconds at a time. Steering under these conditions meant that turning involved sending a command, waiting a few seconds to see if the command resulted in a turn and how much of a turn, and then repeating the process as necessary. A tap of the arrow key looked like it resulted in a turn of about 10 degrees, but it was hard to get a sense of how much of a turn holding down the key would give you, so my strategy was to just send multiple taps as necessary. Because of the lag involved, I would often send a command, not see any result, and then frantically send a bunch more as the robot approached a person obstacle, only to have all of them seemingly arrive at once, turning the robot way past where I was aiming for.

Double 2 telepresence robot at Oregon Zoo screenshot

The scary part is that when the video lags out (as in the image above), you have absolutely no idea what’s going on. Is there a toddler near my wheels? A peacock crossing the road? You have no clue. What you do know, however, is that 4,000 kilometers away you’ve got a not insignificantly sized moving robot that’s doing something. Effectively, it’s not under your control anymore, and that’s kind of terrifying. Like, there were times where I was trying to peer through video artifacts while driving, and then the video froze, and when it came back 5 seconds later there were a bunch of people all clustered around the robot. Fortunately, I didn’t run into anyone, and I had my brother watching out for me, but still, driving is not relaxing under those conditions. 

I decided that a reasonable test of Double 2 would be to go try and find an elephant, figuring that an elephant would be the easiest animal for me to spot. And hey, look!

Double 2 telepresence robot at Oregon Zoo screenshot


Video and audio were noticeably worse while moving, and also seemed to be bad in narrow, crowded areas, possibly because the available LTE bandwidth was reduced. The best experiences I had were while completely stationary and talking to people, or looking at the elephants.

Overall, taking Double 2 to the zoo was equal parts entertaining and stressful. When the audio and video were halfway decent (I’m not even saying good, just decent), checking out the animals and interacting with people was a blast, and I could have stayed there all day. But when the audio and video sucked, it was really frustrating.

Again, I want to emphasize that this kind of connectivity is completely out of Double’s control, and it’s not a criticism of the robot. In fact, it was impressive that the robot did as well as it did, under circumstances that it was definitely not designed for. I’m not sure how Double could solve this even if it wanted to—multiple LTE modems?—or maybe we’ll just have to wait for faster networks like 5G.

Out to the Beach

My parents were going to the Oregon coast for the weekend, so my brother handed Double 2 off to them, and just like that I was headed to the beach. They set me up in their hotel room that evening, and connected me to the hotel Wi-Fi. I logged in to this:

Double 2 telepresence robot screenshot

Heck of a view. I don’t know if the video I was getting was technically high definition, but it looked great.

I can’t really say that it was just like being there in person, but it was a lot like being there in person, in the sense that I could move around, look at what I wanted to look at, and talk to my parents without them having to focus on me the whole time, as they would have to if I was on the phone. It was pleasant and relaxing.

The next day, my dad had a conference at the world famous (or at least, Oregon coast-famous) Salishan Resort, so my mom and I tagged along to see how well Double would do, back on LTE.

Double 2 telepresence robot at hotel

This kind of rough surface was not ideal for the robot. It managed okay, and never fell over, but on a regular basis, the robot would develop a kind of resonating shimmy, which my guess is was caused by the balancing system overcompensating for bumps in the ground. The video would go all wobbly and there would be some very loud rattling, persisting for several seconds or until the robot accelerated or turned or otherwise changed its motion significantly. Sometimes, it continued even when the robot was otherwise stationary, and it was obvious enough that my mom noticed it on her end, and occasionally solved it by putting a hand on the iPad to calm the robot down. This happened at the zoo as well, or whenever the surface that the robot was driving on wasn’t almost completely smooth.

Most of the time, LTE was sufficient for a decent experience here, but from time to time the signal would drop, and things would look like this:

Double 2 telepresence robot screenshot

I tried to keep driving in a mostly straight line until things got better.

We checked out the pool:

Double 2 telepresence robot at hotel

And then headed for Salishan’s putting greens to try some actual off-roading:

Double 2 telepresence robot playing golf

Double 2 happily managed very short grass like this. And it was even possible to play golf with the robot by repeatedly running into the ball:

Double 2 telepresence robot playing golf

The robot wasn’t having it with longer grass or loose dirt, but even these hilly, bumpy putting greens didn’t present a problem:

Double 2 telepresence robot at hotel

Overall verdict on taking Double 2 off-road? It’s a surprisingly capable robot that’s able to handle much more than I’d expected. You wouldn’t want to buy a Double robot specifically for this, but if you have one (or have access to one), you can give it a shot without worrying too much. In fact, the robot was so good at staying upright that, to see what a crash would look like, I had to deliberately cause one: I made the Double drive off of a sidewalk and face-plant into a bush. The robot was totally fine, not even a scratch, and with a sturdy body and iPad case, I imagine it could survive much worse.

Back Home

Back at my parent’s place in Portland, I logged into the robot one last time before asking them to pack it up and send it back to Double. They have a 35 Mbps down, 12 Mbps up internet connection. My experience was fantastically better, the best I’d ever had with the robot. I still had a bit of latency, but the audio and video was high quality and seamless, which significantly improved the “being there” feeling.

My parents were in the middle of packing for a raft trip, and I just sort of hung out for a while, dropping in and out of conversation while I did a little bit of work on my computer. I explored our living room, in the process of redecoration. I bothered my brother’s dog. Attention wasn’t focused on me the whole time, which, I think, would be part of the point of having one of these in your house long-term: You can just be there sometimes, and interact with people like you would if you were physically there. It’s not like a phone call or video chat, where the other party feels obligated to direct all of their attention to you the whole time. Because you’re independent, with freedom of motion, people seem to trust that you’ll be able to just take care of yourself. And largely, they are correct, both from a social and technical perspective, which is where you’ll find a lot of the value of a mobile telepresence robot like Double 2.

What a Telepresence Robot Can Do for You

There are clear value propositions and use-cases for telepresence robots like Double. The Double website leads with two of the most common: “Double gives you a physical presence at work or school when you can’t be there in person.” A personal use case is trickier, especially for a robot that you’d be paying for yourself that costs $3,000 plus an iPad. For it to work well, you also need strong Wi-Fi with good download and upload speeds, which may be an additional investment. For so much money, is Double really better than an iPad running FaceTime?

I'm starting to see how a remote controlled robot can be totally different (than a laptop running Skype) . . . You don't have to rely on others, or be the focus of attention. It's not like a phone call or a meeting: you can just exist, remotely, and interact with people when you or they choose.

Before using Double for myself for a week, I was of the opinion that hiring someone to carry around a laptop running Skype would be essentially the same experience, except way cheaper and able to deal with stairs. But now, I’m starting to see how a remote controlled robot can be totally different, because you have independence and agency. You don’t have to rely on others, or be the focus of attention. It’s not like a phone call or scheduled meeting: you can just exist, remotely, and interact with people when you or they choose. Once everyone gets over the novelty of “it’s a robot,” it’s blissfully easy to just be there as if you were actually, you know, there

For a more detailed perspective on this, you should watch this 4-minute video from Willow Garage. It features Dallas Goecker, who worked at Willow full time from his home in Indiana, using a telepresence robot made from scavenged PR2 parts that eventually became Suitable Technologies’ Beam and Beam+ remote presence platforms.

As for operating the robot outside and on LTE, your experience will vary. Mine ranged from “almost unusable” to “tolerably decent.” If you get lucky, “tolerably decent” is good enough to have a great time meeting people in public, especially keeping in mind that their experience is likely to be much better than yours.

So the bottom line is Double and other robots like it are totally and completely at the mercy of your data connection: if it’s good, you’ll have a good experience, and if it’s bad, you’ll have a bad experience. This is unfortunate, because that’s not something that the robot makers themselves can really solve. As cellular data gets faster and more reliable, telepresence robots will work better and become much more versatile, but at this point, it’s something you’ll have to be aware (and careful) of.

Double 2 telepresence robot at the beach

At this point, I would guess that most people would have a hard time justifying a Double 2 of their own for personal use. But if you’ve been thinking about getting one for your business or school, hopefully the experience that we had has given you a sense of just how capable this robot is. I was surprised, to be honest: most of the time, when you take a robot outside of the context for which it was designed, it’ll fail miserably. Double 2 just kept on going, doing its best to deal with everything I threw at it, and more often than not, succeeding.

[ Double Robotics ]

Thanks to Double Robotics for lending us a robot to play with, and thanks to my brother and parents for putting up with me while I played with it.

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