Automata and Robots
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Research on Traditional Technology from the Edo Period and Modern Robots
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Episode 8: Program Technology for “Movement” and Robots in the World
It is important to be able to “feel” and “review” a variety of information sent from sensors in a robot moving.
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“Feeling, thinking, and moving” is essential technology in developing robots. Of them let me now talk about the “movement” mechanism.
A biped robot can walks on two legs. This may seem natural enough; however, “walking” is actually very complicated and can be roughly divided into three main points.
First, “walking” is made up of a continuous falling forward motion. However, the wonderful thing is that you never actually fall over if you are continuously falling forward. The higher the centre of gravity of an object is the slower falling motion is but conversely it easily falls over when low.
The larger the robot the higher the centre of gravity and therefore the falling over motion is slower allowing the command to “Move the legs and hands in this manner” can be given well in advance. In contrast the legs and hands of smaller robots must be moved quickly as they fall over easily, which is the reason why it is so difficult for small robots to walk.
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Second, “walking” includes securely placing your legs on the floor. Have you ever experienced feeling the impact in your stomach when moving down steps without realizing there were still some to go?
1.4 times the impact of your body weight is applied to the feet when landing. And nearly twice that when running. Human bodies subconsciously absorb that impact when landing. The impact in your stomach was that motion being absorbed.
It is rather easy to make a giant robot walk. However, the pilot would die from the large impact of that walking. If a robot weighs 43 tons the impact applied will be 1.8 times that; about 80 tons. How the walking takes place and how to absorb the landing impact both need to be carefully considered.
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Third, stopping is just as important as walking and moving. Your body wobbles when you suddenly stop swinging a baseball bat or tennis racket. In this case, the heavier the moving part the more difficult the control.
A variety of robots are available in the world today, many of which have slender legs. There is good reason for that. Similar to swinging a bat it is difficult to balance heavy legs as they produce a lot of inertia. Slender legs are lighter and therefore produce less inertia even when heavily moved. The purpose of legs is merely balance. Hence the thicker robot legs are the more difficult control is.
morph3 maintains its balance using interlocking upper and lower bodies. The lower body wiggles to cancel upper body power when the upper body quickly moves. Cars cannot stop suddenly. However, canceling inertia allows for easier stops. Newton’s law is wonderful, isn’t it? It is the key to movement.
Robot “Feelings” depend on how you make them think. Simple AI programs attempt to make decisions using the necessary information extracted from all information got through sensors. However, advanced robots have a lot of sensors and therefore cannot process the necessary information because it is too much for the computer. This is similar where people get tired after too absorbing much sensory information.
Recent high performance robots focus their sense on the force applied to the soles of their feet but not so much on other parts while walking. They select which sensor to use depending on what their AI thinks. Here “Thinking” and “feeling” are regarded as a duo.
For example, Hallucigenia 01 can climbs steps and slopes with its body flat. It slightly moves a leg not being used up in searching for a step to use with the computer concentrating on tactual sensations. It concentrates on and tries to sense whether “There’s anything touching its feet?” all within a short period of time. That sensor information is then transferred to the other leg robots.
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Hallucigenia 01, Eight leg robot
Jointly developed by fuRo and LEADING EDGE DESIGN
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As I am engaged in developing robots I am often asked: “Does Astro Boy actually exist?” or “Will robots revolt like the Terminator?” In fact computers are an aggregate of “ON” and “OFF”. Programs determine whether a bit is on or off. In short, currently it is impossible for computers to have AIs that actually “think”.
By the way, the various robots available today include a cleaner robot, the Roomba. Its mode can change to wall mode when a distance sensor detects a wall. It recognizes the shape of a room by using sensors to detect the various points of it, for example if it detects steps it can avoid falling down them. It is quite a good robot. Current robots are all made by combining their good points only.
As for walking technology MIT has already developed a hopping robot with slender legs. As described above it is reasonable concept.
Moreover, Boston Dynamics is developing a Pentagon funded military robot. It is controlled just like how I described above: The robot never falls over as it moves by leaning forward. It falls forward but immediately puts another leg forward too.
A company in Kitakyushu released the rescue robot “Enryu” in 2004. A human rides the robot when used in disaster relief. For example, it can break open automobile doors that cannot be opened due to a traffic accident. However, humans help and remove the disaster victim from the automobile. The robot never directly touches the victim. So why are human rather than robots used in disaster relief? The answer is for the following reasons: Robots cannot determine either the size or whether the victim is sitting (or lying down) or how big they are and the force needed to hold them. It is still very difficult for robots to make those kinds of decisions.
AIST (Advanced Industrial Science and Technology) made a press-release on a modular type robot that can operate in cooperation with other robots in 2003. Each of the robots includes a magnet module and its form changes depending on how they are combined. AIST seems to think that it could prove useful in disaster relief. A modular robot consists of multiple ordinary robots with each of them combining to form a module. For your information, Hallucigenia 01 is also a modular robot.
A sense of fun can sometimes lead to the creation of technology. The key points of robot can be understood if you understand their technology: “This robot has slender legs so it moves due to such and such technology.” Understanding technology can change your point of view. And it is very interesting anyway.
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[morph3]
Demonstration of complex motion
(Click the image to see the movie.
2 minutes and 56 seconds, 14,706KB)
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Takayuki Furuta
Director of Future Robotics Technology Center of Chiba Institute of Technology
Engaged in developing humanoid robots as the leader of the Kitano Symbiotic System Project, JST robot development group. Has been the director of the Future Robotics Technology Center of Chiba Institute of Technology since June 2003. Developed the humanoid robot “morph3” in 2002 and “Hallucigenia 01” which was produced by integrating automobile technology with robot technology in 2003.
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Automata and Robots 
