Wednesday, July 28, 2021
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Androids Invade!

Robo-Ones Prove Walking Robots Rule

Everybody wants a robot. Not a threeinch- tall pancake-shaped vacuum cleaner that keeps getting stuck under the couch, a robot! Ever since seeing Star Wars, I think we’ve all wanted our very own C-3PO. Sure, R2D2 was cute; but you can’t understand what he’s saying, and he doesn’t go up and down stairs without a lot of lifting by ILM lackies and some postproduction shot editing. If you want a robot to follow you anywhere, you need a biped. I’d go out and buy a Honda Asimo, except that I don’t think MasterCard would approve the ten million dollar charge. So what’s a guy to do?

The Pirkus-R standing on one leg. His footprint is about the same relative size as a human’s.


Ha! Build a real walking android? (I’m going to refer to humanoid robots as “androids”). That’s crazy talk, you say. Honda and Sony have spent close to half a billion dollars developing their androids—you can’t just slap one together in your garage for two grand with a couple of servos. Right? Wrong. Robo-Ones, the coolest toy for adults since the Porsche, have arrived.

Robo-One isn’t a company or product name; it’s a style of android made by hobbyists. It’s like saying “RC car.” There are lots of different styles and approaches, and you can build one yourself! Most Robo-Ones are home built (like RC cars scratch built from components, rather than those that can be bought off-theshelf) but there are a few kits available, and more are coming. Robo-One events, in which these humanoid bots fight it out using martial arts techniques, are themselves proliferating, and the variety of robots make these events extremely cool visually. You don’t have twenty identical robots with slightly different paint jobs going at it. Bots of all different shapes, sizes, strengths, abilities, and colors actively compete.

Roborzoid has been modified to be controlled by a Pocket PC.

The term “Robo-One” is a play on “K- 1” which is a type of kickboxing popular in Japan. Robo-Ones are fifteen-inch-tall androids that were originally designed to box against each other, but they now compete in many different events. Many fight, but some do complex gymnastic moves, stand on their heads, and even dance and sing in unison.

This category of hobby robot started in Japan about five years ago. Since then, the sport has grown from a few dozen robots that could barely walk three steps to thousands of robots that seem to be better articulated than most ballet dancers.


The principles behind Robo-Ones are fairly basic. You take about twenty hobby-grade servos, put them into a humanoid shell, and program them to move. These servos move robot parts much as your muscles and joints are used to move various limbs. Almost all of the current Robo-Ones use off-the-shelf parts, and fairly simple software.

Drop and give me twenty!

So why haven’t they been around for ten years? I think it’s the “Roger Bannister effect.” For centuries it was “known” that humans couldn’t run a mile in less than four minutes. It was a pipe dream. Since no one had done it, it couldn’t be done. Then in 1954, Bannister goes and runs a mile in three minutes and 59.4 seconds. So it went with androids. Getting a robot to walk like a human was impossible, so why try? Then Honda and Sony did it. With the knowledge that it could be done, hundreds of Japanese robot enthusiasts headed to their garages to make their own walking bots.

The Robo-Ones and their medals from ROBOlympics 2004.

And now they’re everywhere. Well, not quite. But you can buy them. Two companies market Robo-Ones worldwide, and many more are planning on selling Robo-One kits by year’s end. The KHR-1 (available from, via was the first kit available in the U.S., but it is now joined by the more advanced Pirkus (available from misterrobotics. com). Both retail for about $1700 as of this writing.

These kits are more expensive than most RC cars, but the wow-factor from your coworkers is also sure to be far higher than you’d ever get from something with four wheels. While both kits are fairly limited in their software, the mother companies are offering updates on an ongoing basis to make programming the robots easier.

The new RoboNova-1 from Hitec RCD.

The Robovie-M will also soon be joining the U.S. Market. This is probably the most advanced Robo-One, both in terms of hardware and software. The Robovie-M was put together by Team Osaka, who were the first ever team to win all five humanoid challenges at RoboCup. The Robovie-M and Roboive-MS will also be available from


A good Robo-One offers “hierarchical control.” Basically, if you tell the robot to go forward, it walks forward. You don’t have to get so specific as to command it to raise the left leg, bend the left knee, rotate the hips, etc. As of now, no off-the-shelf kit offers a suite of such advanced “macros,” but they do allow you to program the robot to do just about anything you can imagine, and both come with a wide variety of pre-programmed moves. The Pirkus is slightly more advanced, in that the software gives you a virtual android on your PC screen so you can see what the moves would look like.

Of course, most Robo- One builders become obsessed with their kits, so software limitations aren’t going to slow them down. Having played with both kits, I got both robots walking in about a day, but I expect the newer versions will be much easier to program. The Pirkus kit also has the benefit of having a built-in accelerometer, so it knows if it has fallen down.

The new Pirkus is two feet tall!

For the hardcore, you can follow the Japanese enthusiasts who’ve made their own. But regular servos won’t do the trick! The force put on a knee joint is far greater than a tendollar servo can handle. If you want to play with Robo- Ones, you’ll need hundred-dollar, hightorque digital models! Several U.S.-based builders have already taken the plunge, so you won’t be alone.

Hitec, Futaba, Kondo, and many other servo manufacturers are all offering digital robotics servos with steel or titanium gears – make sure you buy something strong enough to support the forces you’ll encounter. Buying seventeen $10 servos to save a few hundred bucks will only be wasting $170. The gears will all strip and the servos will be worthless.

ScreenShots of Robo-One control software – Pirkus

So what can a Robo-One do once you’ve gotten it built? Just about anything. These rockin’ robots do Tai Chi, stand on their heads, do summersaults better than a stunt man, easily perform high kicks over their heads, and just about anything else you can imagine and program them to do. With fast servos, they can even jog!

ScreenShots of Robo-One control software – KHR-1

Of course, once you’ve got a Robo-One, you’ve got to show it off. And just like owning an RC car – while it’s fun to play with alone, it’s way better to compete against someone else. At the last ROBOlympics and RoboGames events held in San Francisco, over twenty Robo-Ones made appearances, including several made in America!









RoborZoid does a head stand at RoboGames 2005.


The Demonstration event is the highlight of a Robo-One show. This is where builders get a chance to show off not only their design prowess, but their creativity as well. While most robots are content to show off their high kicks or do a few handstands, one of the best demonstrations comes from Weird-72, a robot based in San Jose, CA. The builder lays an ordinary magazine on a table (about 1/2-inch thick— like RC Driver or Cosmopolitan). Suddenly, the cover of the magazine opens, and a super thin android does a back-flip out of a hole cut into the center of the pages. The robot is no thicker than the magazine, until its feet rotate! Once its feet are angled out, this bot can walk around, roll head-over heels, and even jump! It won’t be long before these droids are doing pirouettes.

Yokozuna-Bot and Robovie-M play Rock-em Sock-em.


Rock-‘em, Sock-‘em Robots get real! Matches are based on boxing, and a bout goes for three rounds of two minutes each. The fights are surreal, and still photos just don’t convey how cool it is to see an android dropping to one hand to use its feet to kick out the knees of its opponent. The bots aren’t as fast as humans, but in terms of flexibility, they’d kick Bruce Lee’s butt. Robots don’t have to limit themselves to the degrees of freedom built into humans. Our knees only bend one way – a bot’s can bend both. And its hip joint can extend and rotate the leg above waist height.

Robovie-M knocks Yokozuna-Bot down at iRex 2003.

While the fights are not autonomous (the builders use RC to tell the robot which move to make and which direction to face), the bots still make the moves by themselves. The operator doesn’t have to tell the bot to “raise left leg while extending right arm for balance” –the motions are pre-programmed so you can attack and defend much more quickly. And the better bots have accelerometers built into them to help ensure that they don’t fall down while executing a move.

And if that’s not enough, the standard boxing rules apply: If a droid gets knocked down (or falls down on its own), it has ten seconds to stand up, just like in regular boxing! In Japan, all matches are called in Japanese, but the countdown is still in English, which gives the matches a weird dubbed-movie feel to them. Should a match go the full three rounds without a knockout, the match goes to the judges – and in an unlikely nod to combat robotics, the judging system is nearly identical to that used in combat robot matches. Three judges allocate points in aggression, damage, and strategy categories. The only difference is that it’s a three-point scale, not a five-point scale.


Roger Bannister would be proud. Robots run the two-meter dash! Unlike a standard trackand- field competition, the ‘bots must start lying down, before standing and running the distance. Just like human events, the fastest time wins. It may sound easy, but unlike boxing or demonstration, the robots must perform the event in autonomous mode–with no humans guiding them.

The arena for the Eagle.


This is probably the most complex and yet the coolest event in Robo-One. It’s very much C-3PO meets James Bond. Imagine having to break into Dr. No’s underground lab. First, the robot must slide down a nine-foot sloping rod. The starting point of this rod is one meter (40 inches) off the ground, and slopes down to about 20 inches. Easy for you, not so easy for a foot-tall robot. Then the robot must run around a corner, cross a two-foot diameter spinning “disk of death,” round another corner, go down two stairs, and finally make it across a three-footlong teeter-totter without falling down. Most wheeled robots can’t do that!

If climbing stairs is so easy, how come Dean Martin had so much trouble?


This is the true test of an android. If it can’t operate in three dimensions, it’s no better than a wheeled bot. While you and I have been running up stairs since the age of two, it’s a heckuva lot harder for an android. Once it’s up on one foot, the droids all too often end up face-planting. There’s a lot of balancing in standing on one foot, and ten times as much when the majority of their body weight isn’t on the contact foot. So this is no easy task. Each stair is only about an inch high, but they’re four inches deep, and the robot must ascend five steps, walk about a foot, and then descend another five steps, all without tripping.


If he can open the door, he’ll get a treat on the other side!

What good is an android if it can walk up the stairs but can’t open the door once it gets to the landing? This event tries to achieve what your dog’s been dreaming of doing for years. Robots can be either RC or autonomous (most are RC). They key onto the door handle (which has been lowered), grab it, open the door, and walk through. Of course, it’s important to be able to have a hand that offers enough traction to grip the door knob, but enough feedback to not break it off by turning too hard or too much. Easy for you, hard for the robot!


Baseball for robots? Why not? The toss is the first step in getting there. This is the only other competition event, besides the dash, that is entirely autonomous. Androids stand about three feet in front of an archerystyle target, with their backs facing the target. They pick up a ping-pong ball, turn 180 degrees, and throw the ball at the target. The center ring is only four inches in diameter, and it’s yet to be done with any repeatable accuracy. Hopefully, they’ll greatly improve the precision of the robots in the next few years, as the Giants could really use some help in their bullpen.


If you plan on competing at a Robo-One event, or you’d just like to see a show, you’re in for a pleasant surprise. There isn’t just one competition. There are seven! Not all bots compete in all categories, but it’s fun to watch the different events. If you want to compete, build a Robo- One and pick your categories! Almost everyone competes in Demonstration and Boxing, but many bots compete in the other challenges as well! Still photos just don’t do justice to how cool these robots are when competing, so I’ve put up videos of all of the latest competitions at to augment the photos included in this article.


While robots come in all forms, sizes, abilities, and prices, humanoids are obviously the coolest of the bunch. And Robo-Ones are the best way to get yourself one. At the recent RoboCup2005, Team Osaka showed off their VisiON Robo-One, which had a built-in 360° vision system and vision recognition software which let it detect objects, avoid them, and kick soccer balls – much like the current capabilities of the Sony Aibo, only in a humanoid form rather than canine.

Like all new technologies, every year will bring radical advancements, and I can honestly foresee five-foot-tall humanoid robots available for sale within five years. They will be used for anything from household butlers to replacing wheeled combat robots for exhibitions. While this may sound optimistic, once you’ve seen Robo-Ones – or any other humanoids – you’ll be amazed by how far the tech has come in the last few years, and how quickly we’re advancing. It may not be cheap, but it sure will be fun! 


Hitec RCD USA, Inc., (858) 748-6948


Pirkus and Robovie

Videos of competitions:

Words by David Calkins