Video demo of the kenzoh humanoid robot )via University of Tokyo)
Our attempts to recreate the human body are often remarkably simple approximations compared to the real thing. Most of the time increasing complexity gives rise to other unforeseen problems but nature has given us one of the most versatile machines, and we know very well how we are designed so we will certainly try to replicate it. At the same time, there are many things that a human body cannot do, which gives rise to bots that look and function very different from our structures. These imaginative bots could function and substitute body parts in stranger ways.
Researchers in Japan are already starting to trek down the path towards an extremely accurate humanoid robot. Researcher Yuto Nakanishi from the University of Tokyo has worked for years trying to develop robots that share the same degrees of freedom as the human body.
His efforts have produced robots called Kenzoh, Kojiro and know Kenshiro, all listed in order of increasing accuracy. The last robot, demonstrated at the Humanoids 2012 conference in Osaka, Japan, has the same skeletal frame as a 12-year-old boy. It is composed to aluminum bones that are connected to 160 muscles with artificial ligaments.
In this iteration, Nakanishi and his team wanted to replicate the human bones better than before. They also wanted to keep the weight ratio of different muscles i.e. thigh to calf weight, true through out the robot. To do that they remodeled the bots vertebrae, knee joints, rib cage etc. to better match the shape of the real body, reducing the total weight of Kenshiro from 100 kg to just 50 kg.
Each of its muscles is made of wire springs or flat elastic material, which is pulled by its own actuator. These motors move entire muscle groups with pulleys. In total, Kenshiro has 50 muscles in its legs, 76 in its trunk, 12 in the shoulder and 22 in the neck. Some of those are flat muscles that give the bot more stability in its neck, spine, arms, abdomen and legs. This robot has the most artificial muscles than any other.
With all these muscles, Kenshiro has 64 degrees of freedom. Even with all those DoF’s, the 5’1’’ Kenshiro can only perform movements of certain body parts at a speed lower than humans. Synching these parts has been a challenge itself, and a lot of work must be done before Kenshiro can walk or perform functions that require every part of the body.
But the body of a robot can be made out of drastically different shapes and material, and still the same tasks can be completed. From the most accurate humanoid bot, we go to the most general robot that may even out perform Kenshiro in a foot race or assisting people.
At the University of Chicago, professor Heinrich Jaeger has created something called a JamBot. This robot is a sphere, which is made of triangles just like a soccer ball is made out of pentagons. Each triangle is a cell full of a granular material, the inside is filled with an incompressible liquid and at its center is an actuator than can vary its volume.
This JamBot can produce locomotion, shrink in size to move through small holes and even grip stuff. The way it works is by “jamming” a triangle cell causing the granular material to change from fluid-like to solid-like with just a small change in confining volume. Different combinations and sequences of jammed cells and changes in volume of the actuator can control the JamBot to roll in any direction.
Unlike Kenshiro, this robot has no hard components and its applications are still being imagined. Jaeger has developed similar bots that can grip objects and its deformability will make it ideal for exploration of hard-to-reach environments.
The JamBot is still tethered to the control unit with hoses and wires but Jaeger says these will all be located inside the robot in the future. A less than useful Hexapod version of the Jambot was also shown off by iRobot. The concept is there, but the functionality is not. More to come on this, I am sure.
Kenshiro’s creator wishes to attain a robot with all of the degrees of freedom of a human. While this feat will be impressive, the creations of our imaginations, like the JamBot, can represent the possibilities of our imaginations, which often are constrained by our physical bodies.