DARWIN-MINI

DARWIN-MINI
Click on the picture above for more information about the DARwIn-mini.

Monday, September 26, 2016

SparkFun AVC 2016


Link to photo album: https://goo.gl/photos/nRTdoWDeTMmd4U1B7







Monday, September 5, 2016

Paper / Book Outline for 3D Printing of Humanoid Robots

Yes, it needs work but this is a quick brain dump of my ideas.



I. Introduction to 3d printing of Humanoid robots.


A. 3D printing and why you should use it?
1. Additive manufacturing instead of subtractive manufacturing.
2. You can create smoother, more rounded, natural shapes for your robots.
3. 3d printing allows you to be more creative and think outside of the box with our robot designs.
4. Cheaper entry level for people to get into robotics if you own a 3d printer.

 

B. What is a humanoid robotics and why should you want to build one.
1. How did the Hobby start in Japan? Hobbyist wanted their own version of the ASIMO robot. The first humanoid robots where built with repurposed Kondo hobby servos for R/C cars and airplanes. First servos used where similar in capability to the XL-320.
2. Humanoid robots try to mimic human movements as close as they can.
3. The best way to interact with humans and use human tools without modification is a humanoid robot.
4. Watch a RoboCup video to see how cool and capable they are.
5. Humanoid robots will start appearing in our everyday lives more and more in the not too distant future.

6. Watch videos of the DARPA DRC robotics challenge to see why robots need a human shape.

C. What are the benefits of 3D printing out a humanoid robot?
1. Cheaper cost to print out brackets then other traditional manufacturing processes if you own a 3d printer.
2. 3d printers are cheaper than most metal cutting CNC machines.
3. Gives you more design options.
4. Standard metal brackets are ¼ to ½ inch 5052 Aluminum Metal. The metal sheets cost around 9.00 dollars for a 12 by 24 sheet.
5. Need cost of an average bracket to print out.

D. Why I started 3d printing out humanoid robots.
1. Testing out a new manufacturing process (experimentation).
2. For me a 3d printing robot is easier to use than a metal cutting CNC machine and a metal bending machine. Creating a metal bracket is a two-step process.
3. It is also not easy to correctly bend a bracket from a 2d object to a 3d object. This is a lot harder than you think. If the bend lines of the brackets in the legs are. different than it can be almost impossible to get the robot to walk.

E. Why start with an open platform robot.
1. Most of the robot is ready to 3d print with only a few modifications.
2. You can share your work with other people.
3. Usually cheaper to build then a closed sourced robot.
4. Easier to ask for help when building or programing (community/forums).

 

II. The road traveled or a brief history of how I got here.
A. The early days. There was a lot of failures! The MakerBot Cupcake was full of possibilities but very hard to use.

B. My first usable bracket! (Picture) I printed it on a UP Plus version 1.1.

C. I can print out a robot now! I now regular print out all of my brackets on my personal UP Plus version 1.2.

III. Servo selection.
A. Picking the right servo to use is the first and most important step of the design process.
1. The selection comes down to Robotis servos vs. Kondo servos.
2. Servos are an actuator which acts as the joints and muscles of a robot. Each servo counts as a DOF for your robot (Degrees Of Freedom).   

3. Your servo will have two servo horns one on each side usually. One will be powered by the servo and the other will be free spinning.
3. A cheap servo selection leads to a cheap robot.

4. A good servo can turn a bad design into a workable robot.



B. Servo selection factors.
1. Price is important as you will need between 16 and 24 servos. You can get by with less but that will decrease the robots capabilities. It is all about how much can you afford. It is a balance between cost and capability.

2. Holding torque of the servo.

3. Speed of servo.
4. Backlash is when a servo comes to a stop but still moves or wobbles. Like a gymnast not sticking their landing. Metal gears usually have less backlash then plastic gears.

5. Metal gears vs. Plastic gears.
6. What is the resolution of the servo motor and internal controller?
7. A Digital servo is a most.
a. Higher resolution than an analog servo.
b. Faster response time, more acceleration than an analog servo.

c. Constant torque throughout the servo travel and increased holding power when stationary than an analog servo.

 

8. Servos need to be Daisy chainable to the controller. If not you will have a control wire from each servo to the controller. This will create a huge mess that you will have to deal with. Also Servo wire nicking is a consistent issue that you will have to watch out for.  

9. Will you have to make your own servo horns?
10. How will the servo horns interact with your brackets?

C. The servo type selected will then tell you the robot size and
weight range.
1. It all comes down to holding torque; The weight of the robot will be determined by how much weight the servos can hold up right without too much stress, overloading or heating. If the servos can barely hold the robot upright then how can it support the robot when walking?
2. Big form factor servos will make it easier to build a larger robot.
3. Just as small form factor servo will make it easier to build a small robot.
4. Compare the size of the MX-106s to the XL-320 using a picture.
5. So you pick the servo based on the size, height and weight of the robot you want.

a. XL-320 < 1 kg.

b. AX-12 and AX-18 servos between 1 kg. and 2.5 kg.

c. MX-28 between 2.5kg and 4 kg.
d. MX-106 between 4 kg and 6 kg.

e. Dynamixel Pro > 5 kg .

 

D. The servo you select can make or break your robot project.
1. The right servo makes it easy to program the robot. The wrong servo makes it almost impossible to program the robot to do anything.
2. Do you want to spend a lot of time programing around weak servos?
3. Try to max out your budget as much as possible on servos. You will thank yourself later.

 

IV. What other hardware or software elements do I need?

A. Servo controller.
1. Open or closed sourced?
2. Is it the best way to control your servos?
3. Is the servo controller powerful enough to Handle 16 to 20 plus servos?
4. How will you connect your servos to the controller?

B. Programming software.
1. Ease of use. Is there a high learning curve?
2. Straight Embedded C++ programming is the most difficult to start out with.
3. GUI inference is very helpful for the first time user.
4. Can you program it like a Claymation movie? The robot replaces the clay figure.
5. Can you program the robot directly and then line capture the servo positions?
6. I use RoboPlus versions 1.1 and 2.1 and embedded C++. They were designed to be used by the Robotis line of servos.

C. Higher level brain then the servo controller.
1. Is the board too big or small for the robot?
2. The price of the add-on computer is a factor?
3. Can you connect it to your servo controller easily?
4. How will you power it?
5. How will you mount it on the robot?

D. Camera.
1. Vision capabilities can add a lot of functionality to your robot like face, color and object recognition.
2. PIXY camera is another option as it does a lot of the processing of the camera image on board.
3. Cameras are cheap and easy to buy.
4. They are usually easy to connect to your controller.

 

E. Battery.
1. Without a battery your robot will be tethered to the wall.
2. Need to get the right amperage and voltage plus capacity?
3. Will it connect to your servo controller?  

 

F. Sensors.
1. Sensors will allow your robot to interact with its environment.

2. Type of sensors need a good list.

3. If you are following RoboCup rules then you can only add sensors that a human has. Allow sensors are eyes (camera), ears (mic) and a way to communicate between robots (Wi-Fi).
4. Sonic distance sensor.
5. IR distance sensor.
6. Kinect like sensor which is both a camera and distance sensor. 
7. Speaker for voice.

8. Mic for voice commands.
9. Touch sensor.

V. Moding and creation of the brackets and body covers for 3d printing.

A. Open platform robots benefits.
1. Sharing of ideas and problems.
2. Gives you a great place to start.
3. Great for first time robotic builders.
4. Someone has already made this robot before. You can learn from their mistakes.

5. Hopefully it has Good documentation.

B. What is a robot bracket?
1. Servo connecter is its main job. Brackets are the bones of a robot.
2. The Brackets need to securely connect your servos together.

3. The brackets will be connected to your servos by servo horns. There is one horn on each side of the servo. Usually one side is powered by the servo and the other side is free spinning.
4. This is the main structure of you robot and needs to support everything your robot does. This is the main part you 3d print out.

C. Why does my robot need body covers?
1. Makes it look cool and give it personality.
2. Can decrease flex of the robot and make it stronger. This is based on how many connection points and where the connection points are on the robot. 
3. You can personalize your robot.
4. The covers can act as a cushion for your robot when it falls. This becomes more and more important as your robot gets bigger and heavier.   

 

D. Best CAD programs to use.
1. Price, ease of use.
2. Autodesk inventor, education license is free.
3. Solidworks questions? Need to talk to someone who uses it.
4. Free software is 123d design and Sketch up.

 

E. How to create a .STL file.
1. Make sure that you can easily convert a .STEP file to a .STL with your CAD program.
2. Show this in Solidworks through pictures and diagrams.
3. Show this in Inventor through pictures and diagrams.
4. Show this in 123d design and Sketch up through pictures and diagrams.

 

F. How to design for 3d printing tips.

1. Added Ribbing and Gussets especially perpendicular along the z layer of the part. If your part fails it will usually fail between z axis layers.

2. Rounded corners and rounded shapes to increase strength.

3. Increase thickness of part to force infill between walls. Think of infill as internal ribbing and gussets. You can create a hollow between walls if the walls are too thin

4. Eliminate as much bridging as possible
5. Always keep track of weights of each individual part and the total weight of the robot. You do not want to max out your servos.

6. If you start with a bracket designed to be created by metal, one of the easy tricks to do is eliminate the weight saving holes of the bracket. This will increase the weight of the bracket but with plastic it will make it stronger less flexible and make it easier and cheaper to print out.

 

VI. 3d printing of the robot.

 

A. 3d printing on your own personal 3d printer.
1. First you need to buy one. Checkout Make’s Ultimate Guide to 3d printing for suggests. This guide usually comes out each year in November and December. 
2. What capabilities will you need (make a list).
3. Support material is very helpful for robot brackets.
4. Can the printer print in ABS?
5. Is the price of the printer in your budget range?
6. Price of the plastic.
7. Ease of use. Is the hardware and software easy to use?

B. Printing out the robot through Shapeways and I,materialize 3d printing services.
1. There are other services but these are the two that I use.
2. Compare prices for parts at both Shapeways and I,materialize before you order.
3. What types of plastic should you use?

a. Nylon is the cheapest but it is very flexible.

b. ABS can be very expensive.

c. Nylon / aluminum is the best of both worlds, strong and tough parts and flex of part is less than ABS. But the parts can be very expensive!!

4. Show how by pictures and diagrams how to upload a design to both services. Also how to start-up a store in Shapeways and how to get the parts into the BETA program.

C. Sharing your robot design.
1. Allows other people to help you with the design and testing of your robot.
2. Thingiverse is still a good place to store .STL files for sharing them.
3. Open up a shop through Shapeways BETA product is another.
4. Share more than just the .STL files. Example is .STEP files which you can change and modify.

D. Tips and tricks I have learned while printing out my robots.
1. Elmer’s purple glue sticks works great and it is safe to use. Put it on the heated build platform to get rid of ABS curling. I use a thin sheet of aluminum with a thin layer of purple glue stick. I have also experimented with borosilicate glass and purple glue stick.
2. I try to keep the temperature of my print room at 80 degrees using a space heater.
3. I enclose the printer with a large cardboard box. This also protects the printer from my cat. I find that I get less curling and better layer adhesion with an enclosed printer. 

4. Warm dry air is great for 3d printing.

5. I also keep my house closed and use the best air filters you can buy because of my allergies. This keeps dust from collecting on your filament.
6. I store my plastic in a plastic container with a lid and inside is a water wick compound.

 

E. Types of Filament you can use.

1. PLA, pros and cons for robot brackets. PLA is usually to Heat sensitive and too brittle.

2. ABS, pros and cons for robot brackets. Good compromise between PLA and Nylon.

3. Nylon, pros and cons for robot brackets. Very strong and tough but it has too much flex.

4. Carbon nanotubes, pros and cons for robot brackets.  Adds increased strength and toughness to ABS. I have just started to use this filament.
5. ABS/Nylon adds increased toughness to ABS.

6. Future filament in the works that looks interest.

7. Too much flexing of a robot bracket when the robot moves can lead to increasing oscillations of the whole. This will then leads to major failure of disastrous results.

VII. Building of the robot.

A. So how do I assemble the robot
1. Make your own assembly manual or use an already created one.
2. Think out how you are going to assemble the robot beforehand.
3. Planning, planning and planning beforehand is key.

4. Sometimes you will have to disassembly part of the robot to assembly another part. Then you will have to reassembly the parts again. This is where documentation and pictures will come in handing. So you can show other people how not to make the same mistakes. For example the DARwIn-OP manual is full of small mistakes on which parts to assemble first.

B. What tools will you need?
1. Jewelry type straight edged screw drivers and Phillip’s screw drivers are a most (sizes 000, 00, 0, 01).
2. Extra lighting over your work table.
3. A build surface that is clean and where you can easily see small screws.
4. Lock-tight glue is dangerous to use with 3d printed parts as it will damage them.

5. Pliers set.

C. Fasteners or glue.
1. Pros and cons of both.
2. Experiment to see which creates the strongest joint.
3. Use both on important joints like in the legs, high stress joints.
4. Glue is like welding in some ways. Welding is how most robot parts are joined together.

D. Zen and robot assembly.
1. Lots of small screws and very tedious work. You need to channel the screw driver. That or have all of your screw drivers magnetized! 

2. Lock-tight can help keep screws from coming louse but the lock-tight will damage plastic parts.
3. Take breaks, no take breaks. Set back and take a deep breath every once and a while.
4. A cool, quiet area with few distractions works best for me. No cats (pets) or kids.
5. Organize and label all parts. Specially screws and nuts!!!.

VIII. Intro to robot programming.
A. How to get started.
1. How do you program the servo controller?
2. Embeded C++ is the usually way.
3. GUI software package that converts high level programming to embeded C++.
4. Motion capture software that takes servo postions and converts them to C++ code.

B. Create basic movements.
1. Start out with upper body movements.

2. Build moves one small movement at a time.

3. Motion capture GUI tool is great for this.

4. Lower body movements are the hardest to get right.
5. This can be a long an arborous process. Great example is that it takes humans one to 2 years to learn how to walk and we are not including stairs.

 

C. Create a basic walk.

1. Start out with the robot balancing on both the right and left foot.

2. Then have the opposite foot move forward a few millimeters.

3. Start with a shuffle step then work towards the robot picking up its moving foot.

4. Create a loop of this motion.

5.  Walking and running is a balance between the speed of the robot legs and the distance between its foot strikes or gait length. 


D. Make your robot dance.
1. GUI software packages like RoboPlus 2.1 makes this easy. There is a 3d computer model of your robot on your computer screen that acts like your robot. You then build the moves using the model. Then when you are done you uploaded it to the robot.

2. Embedded C++ is not for beginners.

3. Another easy way is to connect your robot to a software program. Then you turn the robot servos off and on. You move then to the next position then turn them on and line captures their positions. This way is usually a series of very small moves. Like the Claymation movie process. 

4.

 

IX. Testing of the robot leads to improvements (iteration).

A. what is iteration and why it is a great tool.
1. Small changes to the robot with a 3d printer cost very little.
2. Design and print out small improvements or changes then test.
3. If the part does not work redesign it.
4. The important thing to remember is that failure is okay as it will not cost you that much.
5. Don’t get frustrated if things do not work. See this as a challenge not a road block.

 

B. Think of testing as playing with your robot.
1. You have to have fun or why do a humanoid robot project?
2. You have to have fun or why would you do this in the first place?
3. You can learn a lot about robotics and what works and what does not work.
4. Testing validates your design and tells you what parts you need to improve.
5. Hands on work or testing is the best way to learn anything.

 

C. A robot competition is a great testing ground for your robot.
1. What better way to test your robots functionality.
2. Learn from your issues and make your robot better.
3. Talk to the other roboticist and see how they work or design around their issues.
4. Robogames in San Mateo, US is a great competition to go to.
5. General Lessons learned during competitions or what not to do at your first competition (list).

D. Share your robot at your local hacker/maker space or Maker faire.
1. Feedback is always good.
2. Showing off what you are working on is fun.
3. Making and robotics can and should be a social activity.
4. After you get your robot working you need to do something with it! Not having it collect dust on a shelf or your desk.

 

X. Future ideas and ways to print out humanoid robots.

A. Metal printers.
1. The future is in both professional grade and DIY/ personal grade printers.

2. As robots get bigger, stronger and faster than so do brackets need to get stronger and tougher to.
3. Big issues will be the cost of the printer and cost of the parts.
4. Maybe a good option for a few very important parts of your robot (legs, hips).

B. Resin printers.
1. Examples: Form1.
2. Very detailed and precise objects can be created.
3. Solves the issue of z layer adhesion issues and breakage.
4. The liquid resin is the support material.

C. Better tougher and stronger plastics for FFM printers.
1. ABS/Nylon.
2. Granite and Nao-tube filament to increase strength and toughness.
3. Graphene filament to print out servos and circuit boards?
4. Right now FFM printers are the cheapest and easiest printers to use and to buy.
5. We need better ways to do support material.
6. Plastics are now being design for their properties after they are printed not before.

7. More testing needs to be done on the after 3d printed properties of filament.

 

D. Flexible and non-flexible plastic in the same print.
1. Yes way!
2. Possibilities are endless.
3. May revolutionize bracket creation and design.
4. We getting closer to printing out the whole robot at once now.
5. Flexible plastic for covers would be a good experiment to start with.

6. A part of the bracket can be flexible, while other parts can be rigid.
7. Parts can be made like a samurai sword. Flexible plastic in the middle that is incased by non-flexible plastic on the outside or the other way around may work better? This needs testing! 

 

E. Soft robotics and 3d printing.

1. Build the internal frame by 3d printing.

2. The soft outer shell will protect the internal frame. This could be 3d printed.

3. Soft to the touch.
4. Will the robot be powerful enough to be a Heath assistant robot like Baymax?
5. The old axiom is true. The bigger the robot is the harder it will fall!!

 

XI. Examples of robots to start with.

 

A. DARWIN-MINI project.
1. Parts list and what is needed.
2. List pros and cons of the robot.
3. Price too build is the lowest of any humanoid.
4. Capabilities okay but limited.

B. DARWIN-OP project.
1. Parts list and what is needed.
2. List pros and cons of the robot.
3. Very expensive robot to make and buy.
4. Capabilities are off the charts.

C. BIOLOID-3D project.
1. Parts list and what is needed.
2. List pros and cons of the robot.
3. Good compromise between the MINI and the OP.

D. 4 servo robot project.
1. Parts list and what is needed.
2. List pros and cons of the robot.
3. Cheap and easy robot to put together.
4. Limited capabilities.

XII. Conclusion.

 

A. There is a synergism between robots and 3d printing.
1. Leads to cheaper and easier access to both printers and robots.
2.  Improvements in one area will help the other area.
3. Leads to robot being improved and designed faster. Great help in decreasing development time.

 

B. The future is only limited by our imagination.
1. What do you want a robot to do?
2. What do you want a robot to look like?
3. What cool capabilities do you want your robot to do that no other robot does?
4. 3D printing will help you express your imagination better.

C. Humanoid robots among us.
1. It is just a matter of time. Examples are the DARPA DRC challenge, ASIMO and Pepper robots.
2. Best robot is a robot that can use human tools without a redesign of our tools.
3. Best robot is a robot that can move around in the human environment without issues. The humanoid shape works the best here.


D. What are my next 3d printed humanoid robot projects?
1. A 3d printed adult size humanoid robot for the DARPA Rescue robot Challenge.
2. A robot that can repair itself using an external or internal 3d printer .
3. Thinking outside of the box when designing a humanoid robot. 3D printing will allow me to do this. 

6 Years of My 3D Printing of Humanoid Robots Project and the next Steps.

I am collecting my thoughts and lessons learned from the Last 6 Years, I still think there is a lot more to do with this project. Should I collect all of my thought and ideas and write a book or paper next? You can read below what I have so far.




My 3D printing journey to create a DARwIn-OP Clone.

OR My adventures in additive manufacturing. 

Link to my full article on this project.

I have learned a lot during this project and what follows is some highlights.

This is my first 3D printer. I have a love hate relationship with the MakerBot CupCake. I never printed out a usable bracket with this printer but it showed me the possibilities of what a printer could do.



My first usable bracket. This bracket took a lot of trial and error and a whole new generation of printers to come out for me to print it out. 







 I printed it on a first generation UP Plus 3D printer.   The UP printer is a FDM printer.

"Fused deposition modeling (FDM) is an additive manufacturing technology commonly used for modeling, prototyping, and production applications.

FDM works on an "additive" principle by laying down material in layers; a plastic filament or metal wire is unwound from a coil and supplies material to produce a part.

The technology was developed by S. Scott Crump in the late 1980s and was commercialized in 1990.

The term fused deposition modeling and its abbreviation to FDM are trademarked by Stratasys Inc. The exactly equivalent term, fused filament fabrication (FFF), was coined by the members of the RepRap project to give a phrase that would be legally unconstrained in its use. It is also sometimes called Plastic Jet Printing (PJP)."




I then started my DARwIn-OP project. After lots of trial and error I printed out my first version of the DARWIN-OP. The DARwIn-OP is a open platform robot which made making my clone so much easier.

You can download the plans here. 






DARwIn-OP covers made from nylon by Shapeways. 

"Strong & Flexible plastic is printed with an SLS process that uses a laser to fuse together nylon powder."


"Selective laser sintering (SLS) is an additive manufacturing technique that uses a laser as the power source to sinter powdered material (typically metal), aiming the laser automatically at points in space defined by a 3D model, binding the material together to create a solid structure. It is similar to direct metal laser sintering (DMLS); the two are instantiations of the same concept but differ in technical details. Selective laser melting (SLM) uses a comparable concept, but in SLM the material is fully melted rather than sintered,[1] allowing different properties (crystal structure, porosity, and so on). SLS (as well as the other mentioned AM techniques) is a relatively new technology that so far has mainly been used for rapid prototyping and for low-volume production of component parts. Production roles are expanding as the commercialization of AM technology improves."







First test. Lots of issues but you have to start somewhere.





After more printing, re-calibration of the servos and redesigning of the brackets. Robby the clone is starting to come around but it still needs some work.




After a few more iterations he is more stable.  ("Iteration is the act of repeating a process with the aim of approaching a desired goal, target or result. Each repetition of the process is also called an "iteration", and the results of one iteration are used as the starting point for the next iteration.")




Next phase is to explore new materials such as Alumide from I,Materialise. 

This is also an Selective laser sintering (SLS) process

"Alumide models are constructed from a blend of gray aluminum powder and polyamide, a very fine granular powder. Alumide is a strong, somewhat rigid material that can take small impacts and resist some pressure while being bent. The surface has a sandy, granular look and is slightly porous."







In the future I will explore parts made on metal printers and SLA printers. So stay tune to this blog for more information on my project.

Form 1 SLA printer.




Sedgwick DLP printer.





My first print of a DARWIN-MINI head by a DLP 3d printer.





Metal 3D printing.


'Stereolithography (SLA or SL; also known as optical fabrication, photo-solidification, solid free-form fabrication and solid imaging) is an additive manufacturing or 3D printing technology used for producing models, prototypes, patterns, and production parts up one layer at a time by curing a photo-reactive resin with a UV laser or another similar power source.

Another 3D printing approach is the selective fusing of materials in a granular bed. The technique fuses parts of the layer, and then moves the working area downwards, adding another layer of granules and repeating the process until the piece has built up. This process uses the unfused media to support overhangs and thin walls in the part being produced, which reduces the need for temporary auxiliary supports for the piece. A laser is typically used to sinter the media into a solid. Examples include selective laser sintering (SLS), with both metals and polymers (e.g. PA, PA-GF, Rigid GF, PEEK, PS, Alumide, Carbonmide, elastomers), and direct metal laser sintering (DMLS).

Selective Laser Sintering (SLS) was developed and patented by Dr. Carl Deckard and Dr. Joseph Beaman at the University of Texas at Austin in the mid-1980s, under sponsorship of DARPA. A similar process was patented without being commercialised by R. F. Housholder in 1979.

Selective Laser Melting (SLM) does not use sintering for the fusion of powder granules but will completely melt the powder using a high-energy laser to create fully dense materials in a layerwise method with similar mechanical properties to conventional manufactured metals.

Electron beam melting (EBM) is a similar type of additive manufacturing technology for metal parts (e.g. titanium alloys). EBM manufactures parts by melting metal powder layer by layer with an electron beam in a high vacuum. Unlike metal sintering techniques that operate below melting point, EBM parts are fully dense, void-free, and very strong."

The latest video of my 3D printed robots in action.



Finally a Robot and his printer.



I WILL ADD MORE TO THIS AS I FURTHER ADVANCE THIS PROJECT.

Over the last few years I have been experimenting with 3d printing of robot brackets for my humanoid robot Boomer. I take my robot to many events during the year. The two biggest are Maker Faires and RoboGames. At RoboGames I compete in many events like KungFu, demo, stair climbing and a few autonomous events. So the question many people ask me is why 3d printing and robotics? Why do you not just make the brackets out of metal like everyone else does? The answer is both simple and complicated. I started to do it because I could and not for any other reason. The advent of cheap DIY 3d printers over the last 3 years has given me and other people the access to a new way of manufacturing and customization of parts and objects that we have never have had access to before. So simply I was trying to explore this new manufacturing process at first. As I printed more and more parts for my Humanoid robot I realized that I could be done and two it could be done cheaply. The next step towards my project was when I first saw the DARwIn-OP about two years ago at the Humanoid’s 2010 Robotic Conference. After seeing the robot in person and seeing how capable and ground breaking it was. I decided that I wanted one. The problem was how could I afford it? A new DARwIn-OP from ROBOTIS costs 12,000 USD. So that is how this project idea got started. Simply what was the cheapest way to build my own DARwIn-OP.

What is the Darwin-OP you may ask? DARwIn-OP is an acronym for (Dynamic Anthropomorphic Robot with Intelligence - Open Platform) or DARwIn for short. The DARwIn-OP was developed by the RoMeLa research lab at Virginia Tech in collaboration with University of Pennsylvania, Purdue University and ROBOTIS. ROBOTIS is a world leading South Korean robotic’s company. Their Dynamixel servos are the leading robotic servos in the world and the key to why the DARwIn-OP is so ground breaking. The lead designers of the DARwIn-OP project were Dr. Dennis Hong of Virginia Tech’s RoMeLa and ROBOTIS. It is a state of the art research and development humanoid robot. The DARwIn-OP weighs in at about 2.9 kilograms and a height of 45.5 cm. The DARwIn-OP has won the gold medal for humanoid Kid size 3 on 3 soccer robot class at RoboCup for both 2011 and 2012. The robot is both an open hardware and software project. Being a open project is a great help to me in getting this project to work because all of the 3D files and plans are available online for download.

I tried to 3d printed out all of the parts myself and had Shapeways print a few for me as a fall back option for the hardest to print out parts. DIY 3d printing has advanced a lot in the last 3 years but there are a few parts of the DARwIn-OP that are still almost impossible to print out for a DIY printer. The issues are that the parts where designed to be made from aluminum or thin walled injection molded plastic. The best example is the front body cover. The part needs to be printed out on as a highest resolution as possible for it to work and look right. The problem is that on these high settings the build time is over 16 hours on my 3d printer. A lot can go wrong in 16 hours so I have yet to print out a usable front body cover. That is way I had Shapeways print that part out for me. I then bought 20 MX-28T servos and all of the electronics from ROBOTIS. The DARwIn-OP’s electronics can be bought as a kit. At this point with the robot fully assembled my cost has been about 6100.00 dollars USD. If you do not include the costs of the 3d printers I used. That is still a lot but almost half off of the full price of a factory built one!

 I wanted to print out as much of the DARwIn-OP as I could using a 2,000 dollar or under DIY printer (not a 10,000 dollar plus commercial printer). Using a commercial printer would have been way too easy and not much of a challenge for me. I could have used Shapeways to do all of the printing for me but I wanted to see if I could do it cheaper and if the DIY 3D printers were advanced enough to perform the task. I still had to use Shapeways to print a few of the parts. The two piece head and body cover where the pieces I had them do. I still hope in the future to be able to find a DIY 3d printer or modify the parts so that they can be printed out with a DIY 3d printer. I also printed everything in ABS considering I have found that PLA is not as strong as ABS and is more brittle. The printers that I used where the UP! Plus / Afinia, Thing-o-Matic, Replicator 1 and Ultimaker to print out the parts. I would then pick the best part to use in building the DARwIn-OP. I agree with the review of the Afinia in the Make Ultimiate Guide to 3d printers. It is one of the best printers on the market right now. It so far has printed out about 90% of all of the parts for my clone. I had to do some fine tuning of the printers and the parts themselves to get everything to work. I could not have done this project without the help of Luis Rodriguez , Rob Giseburt, Paul Piong, Roc Terrell, James Rao and Kayla Kim. I used their printers and knowledge to get everything done.

 Next, I had to find a 3D design software program that I liked. I decide on Autodesk 123D Beta version to create my .stl files(Stereo Lithographic). I picked 123D Beta for its ease-of-use and price. 123D Beta is a great value because it is a free download. The .stl file format is what most slicer programs use as input to create G-code. G-code is then use by the printer to print out the object. G-code is a language in which people tell computerized machine tools what to make and how to make it. I learned many lessons during this project. What follows is a few of the most important. I had trouble with many of the part’s walls being too thin or in-between widths. The width of some of the object where 1 ½ or 2 ½ extruder paths instead of 2 or 3 extruder paths. Many DIY printers cannot handle this problem well and it may cause a hollow cave within the object walls. This hollow cave could weaken the strength of many of the parts. We added cross-holes in some of the object’s walls to fix this. The DARwIn-OP covers also were very close to being less than one extruder path, which also caused many printing issues. Which is why I had Shapeways print many of the covers out with their powered laser 3d printing process. I also learned the value of a raft and support material. Support material is used when an object’s walls exceed a 45 degree overhang or a screw hole or a bridge in the object. The UP! Plus printer’s software supports the use of support material without any input from the user. The software of the Thing-O-Matic and the Replicator 1 can use support material, but it takes fine tuning, adjustments and a lot of experimentation for it to work. A raft is a technique used to prevent warping. Parts are built on top of a raft of disposable material instead of directly on the build surface. The raft is larger than the part and so it has more adhesion. Even with a raft the UP! Plus printer and many of the other printers I used where still having trouble with many of the larger parts curling. I solved this by upgrading the heated build platform of the UP! Plus to glass covered with Kapton tape. A heated build platform is a requirement if you want to print with ABS. The platform is usually heated to temp of around 110 degrees Fahrenheit. Even with all of this work, I still had to play around with the orientation of many of the parts on the build platform because the orientation of the part on the build platform can affect the way it is printed. I also still had to use a raft on many of the parts because the support material was not sticking to the build platform. We also had to add temporary support structures on many of the parts printed on the Thing-O-Matic and Replicator 1 because of issues getting support structures to work on them. I also learned that one of the most important 3d printing skills is to become very efficient at leveling the build platform of all the printers I used for this project! A Level building platform will greatly increase the quality of your prints. I used the paper leveling trick, where you use a sheet of paper to set the extruder height from the build platform. If the piece of paper can freely move between the extruder tip and the build platform you are okay. If it does not, then the extruder tip is too close. If it moves to easily or you see a gap then it is too far away. I have been warned about ABS shrinkage during cooling. I have not found this to be a problem because all of the slicing programs that I use take this into account. A slicing program is what you use to take a .stl file and create a g-code file that your 3d printer can use.

It may not seem obvious, but getting all of the fasteners and servo horns that I needed for assembly was a huge issue for me. I found through trial and error that McMaster-Carr in Chicago is the best place to order fasteners in the US. Many companies including McMaster-Carr require you to buy a minimum of 100 of each screw or nut when you may only need a few. This can very easily inflate the cost of assembly. I also bought horns and brackets directly from ROBOTIS because they were the only company that could get me the part quickly. The rumor is that ROBOTIS is going to start selling a fastener and servo horn kit along with its electronics kit for the DARwIn-OP. This will make it a lot easier for future fabricators to assembly a DARwIn-OP from scratch. The downloadable assembly manual was a great help because it has an detail inventory list of all the fasteners you need. I used it to fill out my fastener orders correctly. Assembly of the DARwIn-OP was somewhat straight forward. There are 3 manuals online that can be downloaded from the internet. The manuals are a fabrication manual, electronics manual, and an assembly manual. Like building any robot kit the process was both time consuming and tedious. There were about 800 hundred screws and nuts for the assembly. The manuals were very helpful in the assembly process and broke the assembly down into many small steps. All three manuals were very helpful in getting through the assembly work of the DARwIn-OP. I must say that the manuals where the most comprehensive and detail manuals that I have ever worked with. I must thank Dr. JK Han for all of the tireless work he put into in the writing and creation of all three manuals! I just always assumed that the best way to connect two brackets together was to use screws, nuts and bolts. This works great for metal brackets but is not the ideal way for plastic brackets. I bought and have experimented with different types of plastic glues. I am now gluing two 3d printed brackets together instead of attaching them with screws, nuts and bolts. As I think the glued attachment is stronger than a screwed attachment for plastic. I learned so many new things while working on this challenging project. One is the interesting comparison between what Shapeways would charge to print out the parts and what it would cost in plastic to print them on a DIY 3D printer. I used almost two spools of plastic about 90.00 USD. The cost of Shapeways to print out the DARwIn-OP is almost 1000.00 USD. That cost is close to the cost of many DIY 3D printers, and in my opinion the quality of the print is 70% to 80% of what a professional printer can. I think that I am now close to proving that DIY 3D printing is not just for rapid prototyping it is for making your finished pieces. The pictures show my success and process so far. I can print out all of the brackets, but I am still having trouble printing out all of the DARwIn-OP covers. One option I have consider is having all of the Darwin covers printed out by Shapeways as they are the most difficult parts to get right. Total cost for all covers is about 400 USD. So step one is done which is assembly. I am now one step closer to fully cloning the DARwIn-OP.

 The next step is to download the control software for the robot and get it to walk, talk and see! Yes the DARwIn-OP can talk; it has both a mic to hear with an speakers to talk with! It can also see by using a camera in its head. You download the control software to the fitpc in the robot which has a Linux OS. I will then try to run my version of the DARwIn-OP with as few modifications to the software and hardware as possible. I may need to redesign some of the brackets and structure of the robot because it was design to be made from aluminum. My plan is to redesign only the parts that break then make them stronger. As I do not want to add extra weight unless I need to. That is one of the great benefits of personal manufacturing. If something does not work redesign it and print it out. You can do this as many times as needed because the cost of a part is only a few dollars and you just have to wait for it to be printed!

After the robot is fully functional the next step will be in redesigning its covers or modifying its covers for cosmetic or for functional reasons. Cosmetic ideas are to make it look like my favorite humanoid robot’s Robbie, Gort or C3-PO. I will leave the functional redesign to the imagination of the reader. What would you want a Humanoid robot to do and what do you think it should look like to do it? My best example is a fully articulating hand with fingers. (more) As I work on this robot and make it as good or better than then the original I have come to realize that I may never be fully done with this project or idea. I think the only limit to this project is my imagination. This I think is the greatest benefit that we will get from the personal fabrication movement. I think it has opened up limitless possibility for an individual to fully explore in solid form their dreams, ideas and imagination.


Link to my Instructable


Michael Overstreet Bio: He is a computer programmer by day and an amateur roboticist by night. Michael and his humanoid robot Boomer have competed in the last six Robogames and have won multiple bronze, silver and gold metals. For the past 3 years he has been experimenting with 3D printed robot designs at his local hackerspace (Cowtown Computer Congress Kansas City, MO) which he is a founding member of. He is an active member of the 3D printer community and he is working on his own 3d printer design. He also has been a grass roots supporter of the Kansas City Maker Faire as well as attending all of the national Maker Faires. People who are interested in his adventures in robotics should check out his blog "I, Bioloid". He is currently exploring open-source 3D printed robotics.




Monday, August 22, 2016

M3D Pro: Feature-Packed 3D Printer for Improved Reliability by M3D LLC

I have the Micro M3D. It is a great printer to travel with. Plus it is a very reliable and easy to use printer. I hope the PRO will have the same characteristics with increased dimensional accuracy for robot parts.


Link to Kickstarter!