This post is a followup from a previous post on invisibility experiments that can be done at home (http://salviusrobot.blogspot.com/2008/05/diy-invisibility-projects.html). In this post I am elaborating on the concept of using heat to bend light. Heat bends light because it excites air molecules that the light is traveling through. The excited air molecules move differently than they would normally and thus conduct light differently as well. In this experiment you will be able to see exactly how much light is actually distorted by the air molecules. Although this experiment is not necessarily useful for hiding an object completely it does provide insight into how a device could mask its existence by bending light. Again, extreme heat is not the safest way to bend light but it dose seem at the moment to provide an excellent mechanism for doing so. The key for making this experiment practical for making something invisible would be to find a way to agitate the air molecules without using something as dangerous as extreme heat.
I have been a bit busy lately but I have some very exciting improvements that I will be making on the robot sometime in the next few weeks. While going through some old photos of the robot I was surprised to see how much the robot has changed since I first started building it. Probably the most noticeable changes have occurred in the design of the robot's face. The first face I built in 2007 and it had very little mobility and contained very few sensors. In fact the only sensor it had was a single inferred motion sensor that I had removed from a toy security alarm.
The first head design (1) was extremely simple. The dome-shaped head housed only a motion sensor alarm and had a large speaker that could be plugged into a computer to make the robot speak. That first version was radio-controlled but the receiver had to be removed as soon as the robot got more motors than the receiver could control. While researching what the best way to control the robot was a second head was being prototyped.
The second head (2) was a cardboard cutout that could be easily modified and fitted with all sorts of sensors to test them out. Two speakers were added to this head along with a webcam that could be used to see what the robot was observing. The cardboard head fixed a lot of the problems that the first head had. The first head had lacked sufficient flat surface area to mount sensors and despite its appearance it lacked the volume to contain sophisticated circuitry.
After the cardboard head was thoroughly tested a few modifications were made and it was cut apart to be used as a template to cut sheet metal pieces to make a metal version (3) that would be much sturdier. The black painted metal housing of an old cassette player became the robot's new face. Only two things were changed from the original cardboard template. The first change was that the upper portion of the head was re-measured to provide a rounder top of the head so that the head could have more horizontal interior space. The second change was that the sharp point at the bottom of the chin was completely eliminated. This allowed the head to lean further forward to look at the ground in front of it.
The third head was nearly perfect although it had a few problems with stability due to the fact that the sheet metal was somewhat flimsy and there was no real secure way to mount it on the robot's body. Because of this fact a fourth head was designed. This head (4) had a thick metal plate for the front of the face that had to be meticulously rounded out by hand in order to make it the correct shape. The ears from the previous two versions of the head were enlarged and recessed into the sides of the head to protect them and a plexiglass face plate was cut out. The face plate could easily have holes drilled in it for sensors and many more could be made to replace it. Many of the previously used sensors were moved to the face plate and securely mounted on or behind the protective layer of the plexiglass. The final thing was to create a cranium that had enough volume to hold many electronics. To do so the original plastic domes used on the first version of the robot became re-recycled by putting them together to form the curvature of the head's cranium.
The fourth head is the strongest most versatile head yet built. It incorporates all of the best features of the previous versions that were created during the robot's evolution. I found that the most important features were flat surface area for mounting sensors and lights, volume for containing electronics, and structural integrity but along with these features there was one more aspect that I was looking to accomplish more in the fourth head than in any other version. I wanted the head to look friendly. I wanted to make the robot have a face that didn't necessarily replicate the features of a human face but would still be identifiable as a head which arguably was a major flaw of the first model of the head that was built.
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| Evolution of the Salvius Robot head design (1: oldest, 4: newest). |
The second head (2) was a cardboard cutout that could be easily modified and fitted with all sorts of sensors to test them out. Two speakers were added to this head along with a webcam that could be used to see what the robot was observing. The cardboard head fixed a lot of the problems that the first head had. The first head had lacked sufficient flat surface area to mount sensors and despite its appearance it lacked the volume to contain sophisticated circuitry.
After the cardboard head was thoroughly tested a few modifications were made and it was cut apart to be used as a template to cut sheet metal pieces to make a metal version (3) that would be much sturdier. The black painted metal housing of an old cassette player became the robot's new face. Only two things were changed from the original cardboard template. The first change was that the upper portion of the head was re-measured to provide a rounder top of the head so that the head could have more horizontal interior space. The second change was that the sharp point at the bottom of the chin was completely eliminated. This allowed the head to lean further forward to look at the ground in front of it.
The third head was nearly perfect although it had a few problems with stability due to the fact that the sheet metal was somewhat flimsy and there was no real secure way to mount it on the robot's body. Because of this fact a fourth head was designed. This head (4) had a thick metal plate for the front of the face that had to be meticulously rounded out by hand in order to make it the correct shape. The ears from the previous two versions of the head were enlarged and recessed into the sides of the head to protect them and a plexiglass face plate was cut out. The face plate could easily have holes drilled in it for sensors and many more could be made to replace it. Many of the previously used sensors were moved to the face plate and securely mounted on or behind the protective layer of the plexiglass. The final thing was to create a cranium that had enough volume to hold many electronics. To do so the original plastic domes used on the first version of the robot became re-recycled by putting them together to form the curvature of the head's cranium.
The fourth head is the strongest most versatile head yet built. It incorporates all of the best features of the previous versions that were created during the robot's evolution. I found that the most important features were flat surface area for mounting sensors and lights, volume for containing electronics, and structural integrity but along with these features there was one more aspect that I was looking to accomplish more in the fourth head than in any other version. I wanted the head to look friendly. I wanted to make the robot have a face that didn't necessarily replicate the features of a human face but would still be identifiable as a head which arguably was a major flaw of the first model of the head that was built.
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| How hardware is connected in Salvius (arrows show data flow). |
I was looking for an alternative to a CAD (computer aided design) program so that I could do some simple work with 3D models of the robot. I have used Google SketchUp before and I was very satisfied with how it works but it wasn't until recently that I thought to use it for modeling projects. Google SketchUp is simple and easy to use compared to many other free 3D graphics programs that are available. Although SketchUp lacks the advanced features of programs like AutoCAD which can actually be used to make the objects that you draw by feeding the file into a CNC milling machine it is still very useful for creating conceptual images and animations.
Exporting 2D images from SketchUp:
By choosing SketchUp I was sure that I would not using these models to create parts but to simply to model form and function of the robot so that I could generate images like the ones bellow or potentially to create animations. The 3D image part is easy as SketchUp has a built-in image exporter: (File --> Export --> 2D Graphic...). Alternatively, if for some reason you are unable to use the built-in exporter you can always just take a screen capture by pressing the 'PrintScr' key on the keyboard and then right clicking and selecting paste in a blank word or image file.
Exporting 3D images from SketchUp to Alice:
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| Robot model loaded into 3D world |
As for my intention to create 3D animations of the robot, that would be a bit more difficult. I learned programming using a language called Alice. Alice is a beginner programming language that uses its code to control 3D objects in a simulated world. SketchUp saves by default in a .skp format that as far as I know only SketchUp can read, but it can export files as a .dae format which can be read by some other 3D object programs. In order to load 3D objects made in SketchUp into Alice they first need to be converted to a .ase format. The process of doing this is a bit complicated but here it goes:
- You will need to download and install/extract the following programs (all are free to use).
- GoogleSketchup: http://sketchup.google.com/
- Blender: http://www.blender.org/download/get-blender/
- Biturn: http://mirex.mypage.sk/
- Alice: http://www.alice.org/
- Export your object made in SketchUp as a .dae file by going to File --> Export --> 3D Graphic... and then save it with a .dae after the name.
- Open Blender and import the .dae file using File --> Import... and then choose your .dae file. If your object looks broken or distorted in blender you may have to go back to SketchUp and open your original .skp file. Press 'Ctrl+a' on the key board to select all parts of the object then right click on it and choose 'Explode'. You must then re-export it as done in step 2.
- In Blender go to File --> Export... and choose the .obj format. Export the .obj file.
- Open Biturn and open your .obj file. Then export it as a .ase file.
- Run Alice and open a blank world. Go to File --> Import... and choose your .ase file. It should load and you may have to re-size it as it may be out of proportion with the rest of the world.
You can now experiment by writing your own code to move the object. You can also add other pre-made objects to the world to make it more interesting. Alice has a built in video exporter so that you can export your videos directly as movies.
My completed 3D animation using my custom model:
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| Completed 3D model of Salvius Robot |
One of the benefits of having the robots on-board computer mounted in the recessed space on the robot's torso allows modifications to be made to the robot's programming "in the field" or when no other wireless device is available. On Salvius the computer is mounted so that it can fold out to expose the keyboard. Salvius uses GNOME as the GUI for its Ubuntu installation. The computer is a Lenovo Ideapad S10e. When closed the bottom fans face outward so that the computer does not overheat.
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| Laptop folded out to modify programming. |
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| Laptop closed. |
What is a robot? A robot by definition is something that can make decisions based on some sort of logic.
1. (noun) automaton, robot, golem
a mechanism that can move automatically
Synonyms: golem, zombi, robot, zombie, automaton
a mechanism that can move automatically
Synonyms: golem, zombi, robot, zombie, automaton
Humans have a natural tendency to fear that which they do not understand. It is interesting when one reads common words that are assigned the same meaning as 'robot' that the names have the commonality of being portrayed by monsters. A zombie; something without logic, acting on pure instinct. The Golem; a entity of Jewish mythology. The Golem was a mass of inanimate matter that was given life through magic incantations. The Golem proceeds to serve its master but over time becomes more independent and more difficult to control. Eventually the golem becomes destructive and destroys its master unless the master can erase the magic life-giving words from its forehead.
A good friend of mine once said that it is perhaps the things we dislike the most about others are secretly the things we dislike the most about ourselves. If this is true than the reason so many people would associate robots with golems is that they secretly fear that they will become like us. We must remember that humans have killed humans and polluted our world for centuries. We have wiped other species out of existence for pure enjoyment. We have split the atom and unleashed its destructive energies on countless innocent lives.
If the human species is to learn to live with its self it must first learn to live with others, even if the others it lives with are intelligent machines.
robot. (n.d.). Synonyms.net. Retrieved January 6, 2012, from Synonyms.net Web site: http://www.synonyms.net/synonym/robot
I visualize a time when we will be to robots what dogs are to humans, and I'm rooting for the machines.
- CLAUDE SHANNON, The Mathematical Theory of Communication
The danger of the future is that men may become robots. True enough, robots do not rebel. But given man’s nature, robots cannot live and remain sane, they become “Golems,” they will destroy their world and themselves because they cannot stand any longer the boredom of a meaningless life.- CLAUDE SHANNON, The Mathematical Theory of Communication
- ERICH FROMM, The Sane Society
If you make [robots] perfectly realistic, you trigger this body-snatcher fear in some people.
- DAVID HANSON, CNN.com, Nov. 23, 2006
- FRED HAPGOOD, Discover Magazine, June 2008
Any sufficiently advanced technology is indistinguishable from magic.
Arthur C. Clarke
Arthur C. Clarke
It is the oldest plot that robots take over human civilization but the truth is that this has already happened. Your car now computes fuel usage and some even parallel park on their own. The fact that we have used robots for almost every modern application is monumental. Robots can revolutionize the way we live. It is impossible to stop the progression of technological advancement, what is left now is for us to decide what we are going to do with it.
Up until now the left arm of the robot has been a bit awkward due to its width of 7.5 inches. I originally built the elbow this way because it needed extra parts on either side of the gear box to increase torque and to support the weight of the arm all because this arm is excessively heavy compared to the opposite one which did not require the additional torque to move.
This new configuration for the robot's elbow joint is actually more stable, secure, and it reduces the previous awkward width of the joint. On top of that there was also a small wight reduction because a small set of metal spacers was no longer needed. Although this amount is insignificant (only a few grams) it is still that much less weight on the robot.
This new configuration for the robot's elbow joint is actually more stable, secure, and it reduces the previous awkward width of the joint. On top of that there was also a small wight reduction because a small set of metal spacers was no longer needed. Although this amount is insignificant (only a few grams) it is still that much less weight on the robot.
Here are before and after pictures of the elbow joint:
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| Elbow joint before modification. |
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| New joint. |
The name Salvius originates from ancient Rome. Although this article is straying from the usual technicalities of the Salvius robot I thought it would be interesting to write about some other Salviuses. Through history this name has been held by some extraordinary people the likes of which the world has not yet forgotten.
There was a Salvius who was a Roman flute player, Gāius Salvius Līberālis a Roman aristocrat stationed in Britain and the subject of the Cambridge Latin Course Book II, Salvius (bishop), saint and Bishop of Albi in Gaul, Salvius (Amiens) a saint and bishop of Amiens in Gaul, Laurence Salvius (aka Laurentii Salvii, 18th century), of Stockholm who published the works of Carl Linnaeus.
(above) a coin from 7 BC bearing the image of Augustus AE Dupondius. This coin was made by moneyer M Salvius Otho. The reverse side of the coin bears the moneyer's name.
From Wikipedia, the free encyclopedia: "
Salvius (died c. 100 BCE) was a flute player who was proclaimed king by the rebelling slaves of ancient Sicily during the Second Servile War. He assumed the name Tryphon, from Diodotus Tryphon, a Seleucid ruler. For some time, he waged war against the Romans.
Gaius Salvius Liberalis (fl. 80s CE) was a Roman aristocrat and general, who held civil office in Britain and a religious office in Rome.
The historical facts about him provide the basis for the fictional character Gaius Salvius Liberalis in the Cambridge Latin Course. He grew up in Italy and moved to Rome, where he became very successful in the position of a senator and lawyer. He then became an Arval Brother.
The Cambridge Latin Course (CLC) is a series of textbooks published by Cambridge University Press, used to teach Latin to secondary school students. First published in 1970, the series is now in its fifth edition, and has sold over 3.5 million copies. It has reached high status in the UK, being the most successful Latin course in the country and used by 85% of Latin-teaching schools.
Salvius or Sauve (fl. c. 580) was a bishop of Albi in Gaul who was later declared to be a saint."
In many cultures, names have been thought to have special properties. The Planes Indians believed that a name could be bought, sold, or even stolen.
An online search provided this as a result for the meaning behind the name Salvius.
An online search provided this as a result for the meaning behind the name Salvius.
- The name of Salvius indicates you are a patient, meticulous person who enjoys working in a very detailed, systematic way, in such fields as mathematics, science, mechanics, computers, or engineering.
- You do your best work when there is no disruption, as you do not easily adjust to interference and changes once you start a project; also you like to work step by step at your own speed.
- Your infinite patience would allow you to develop intricate, involved skills to perfection.
- However, it is not easy for others to work and live with you as you deliberate so long in arriving at conclusions and allow small details to restrict your point of view.
- Although the name Salvius creates the urge to be both logical and technical, we emphasize that it limits your versatility and scope, tuning you to technical details exclusively.
- This name, when combined with the last name, can frustrate happiness, contentment, and success, as well as cause health weaknesses in the elimination system, which can lead to other complications.
Resources: http://en.wikipedia.org/wiki/Salvius_(disambiguation), http://www.kabalarians.com/cfm/DisplayNameAnalysis.cfm
http://www.kabalarians.com/m/Salvius.htm.
Images used with permission of www.wildwinds.com
Hundreds of dollars can be saved by recycling used electronics.
Since the beginning of the Salvius robot project it has been a major goal to spend as little money as possible. Although at first that goal might be said to be the equivalence of "cheaping out" on the robot, but in my opinion the price of a few hundred dollars far exceeds the price you pay for spending thousands. Many companies and laboratories have put millions of dollars into the development of robots only to have their design become obsolete the following year.
Since the beginning of the Salvius robot project it has been a major goal to spend as little money as possible. Although at first that goal might be said to be the equivalence of "cheaping out" on the robot, but in my opinion the price of a few hundred dollars far exceeds the price you pay for spending thousands. Many companies and laboratories have put millions of dollars into the development of robots only to have their design become obsolete the following year.
As Salvius becomes inevitably obsolete it will be no great loss to anyone who contributed money to the robot's creation. The fact that very simple and easy to replace parts were used in Salvius's construction also weigh greatly in the economic equation. Accidentally burning out a $100 controller is a waist but at this point in the robot's construction no controller has cost over $30. Salvius's plywood frame, although lacking in appearance compared to the laser-cut plastic housing of other robots, is composed of industrial scrap that would have otherwise ended up in a landfill.
Many of Salvius's other components including plexiglass and PVC plastic parts are all odds and ends of other projects that would normally be thrown away. So many parts of this robot have been recycled from other projects that if they were to all be purchased brand new the total cost would be over $2000 but by recycling Salvius has only costed a mere fraction of that amount. It goes to show that ingenuity and determination can easily triumph over economic barriers.
The photo right shows Salvius after the recent upgrade of the drive-base. The new lower chassis is more efficient than the cumbersome previous version. The wheels have been left off for now because there is still no motors to drive the wheels. This new design also allowed the torso motor to be directly connected to the upper body which will save a lot of space.The narrower design of the new lower body is closer to the eventual goal of building a pair of biped legs for the robot. Before legs are built however, it is more likely that a gyroscope will be used to get the robot to balance on two wheels. For now the robot will remain wheel-less until I get some motors to drive the wheels.
The new chassis's design has also reduced the robot's overall height. This is acceptable as the robot is still tall enough to do everything that a human can. The reduction in height also reduces the intimidating factor of having a six-foot tall robot staring at you.
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| Image by mielconejo (Creative Commons) |
Along with being one of my personal favorite authors, Asimov was also an inspiration for the creation of this blog where I write about my recent progress with the Salvius robot. It was about a year before I created an account on blogger, that I came across this quote while searching the web for something inspirational to say in an English paper. It took me about a year to track it down my original paper to find the quote again but now that I have found it I plan to make it easier to find by placing it in this post. Here it is:
“You must keep sending work out; you must never let a manuscript do nothing but eat its head off in a drawer. You send that work out again and again, while you're working on another one. If you have talent, you will receive some measure of success - but only if you persist.”
― Isaac Asimov
I felt that this one quote wholly embodied what I wanted to do with my robot project. My goal is as it has been for the longest time. I want to make a humanoid robot that can compete with some of the the most advanced robots in the world. I want to compete with those robots not only on a technological basis bot on a public basis because the robot itself means nothing if it remains a private hobby. I want to document my progress and to share it with the world. People are the most important part of robotics. Without people there would be no need for robots nor would there be anyone to make them in the first place. I believe that people can make a difference by contributing knowledge to the internet so that it can be absorbed by the global intellect of every person on earth. Once an idea is out there it can be built upon and it takes on a life of its own. That is my dream for robotics. "I don't believe in personal immortality; the only way I expect to have some version of such a thing is through my books." (Asimov).
Degrees of freedom in the human body in relation to robotics.
In robotics degrees of freedom (DOF) are the amount of movable joints that a robot has. Essentially the more DOF that a robot has the more it can move and interact with its environment. Degrees of freedom are measured as the total amount of all the degrees of freedom of every moving part. For robotics we do not actually include the exact amount of moving parts that a robot has because that number would be astronomical. Things like individual gears and links of chain must be excluded in order to provide an accurate number comparable to other robots. DOF are measured in robotics by determining the type of joint; A joint may provide one or two degrees of freedom.
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| Hinge or sliding joints provide one degree of freedom. |
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| Cylindrical joints provide two degrees of freedom. |
Example from Wikipedia the free encyclopedia: "A human arm [excluding the hand] is considered to have seven DOFs. A shoulder gives pitch, yaw, and roll, an elbow allows for pitch and roll, and a wrist allows for pitch and yaw. Only 3 of those movements would be necessary to move the hand to any point in space, but people would lack the ability to grasp things from different angles or directions. A robot (or object) that has mechanisms to control all 6 physical DOF is said to be holonomic. An object with fewer controllable DOFs than total DOFs is said to be non-holonomic, and an object with more controllable DOFs than total DOFs (such as the human arm) is said to be redundant.
When building robots that are humanoid in appearance it is often helpful to look at the underlying features of human anatomy. Joints are what allow robots to move and interact easily with their environment. When the DOF of every movable and semi-movable joint in the human body is added up that gives us 230 DOF.
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