Introduction: FOBO Bipedal Walking Robot

FOBO is the fourth prototype from Project Biped.  It is a 3D printed, self-contained, statically balanced, bipedal robot. It has 8 DOF (degrees of freedom) and can walk around its environment and avoid obstacles using an ultrasonic range sensor.  All of the designs, instructions, source code, and parts lists are provided for free.  FOBO was designed to be easily made by anyone with a low cost 3D printer and an interest in learning about robotics. 

Step 1: Static Walking

FOBO walks statically meaning that at every frame of the animation it is balanced and won't fall over if it stops.  The walking cycle is 10 key frames with 10 frames interpolated in between each frame.

Step 2: Get the Parts

FOBO uses an Arduino Uno microcontroller to actuate 8 servo motors.  It also has an ultrasonic range sensor so that it can walk around without bumping into things.  FOBO is powered by a rechargeable lithium ion battery that lasts for a couple of hours on a full charge.   All of the parts together cost about $200.  Here is the full list of the the parts along with links to the vendor, price, and quantity.  Note that none of the vendors listed are affiliated with Project Biped ... they are just where I bought my parts from.  If you find a part cheaper from another website let me know and I'll update the list.

Step 3: Print the Robot Parts

FOBO is made up of 17 3D printed plastic parts.  The full list of diagrams showing where each part goes can be found here and all 3D stl files for each part can be downloaded here.    I printed FOBO using an open source Makerbot Thing-O-Matic 3D printer.  All of the parts can be printed in about 18 hours (depending on your printer and settings) with about $10 worth of plastic (193 cc is about 1/5th of a standard spool of plastic).

Step 4: Set Up the Servos

FOBO uses 8 servos to move around.  These need to be aligned before construction begins to make calibration easier.  You can access the presentation with animated instructions here (the image is a screen shot of the presentation). 

Step 5: Assemble the Right Leg

FOBO's right leg has 5 printed parts and the following :

4 servos
2 screws  3M 16mm
2 screws  3M 12mm
4 screws  3M 8mm
1 nut 3M

You can access the presentation with animated instructions here (the image is a screen shot of the presentation).

Step 6: Assemble the Left Leg

FOBO's left leg has 5 printed parts and the following :

4 servos
2 screws  3M 16mm
2 screws  3M 12mm
4 screws  3M 8mm
1 nut 3M

You can access the presentation with animated instructions here (the image is a screen shot of the presentation).

Step 7: Assemble the Frame

FOBO's frame has 4 printed parts and the following :

2 radial ball bearings
2 washers
2 screws  3M 16mm
6 screws  3M 12mm
4 screws  3M 8mm
1 Arduino Uno board
1 Arduino Servo shield board

You can access the presentation with animated instructions here (the image is a screen shot of the presentation).

Step 8: Connect the Electronics

FOBO's has the following electronic parts :

4 servo extension wires 6"
2 sections of wire wrap 14" each
1 rocker switch
1 fuse 5 amps
1 DC to DC voltage regulator (5v/6v)
3 solderless wire connectors (female)

You can access the presentation with animated instructions here (the image is a screen shot of the presentation).

Step 9: Put the Head and Battery Case On

FOBO's head is two printed parts and the battery case is a single printed part.  The other items that you'll need:

1 lithium ion battery 2 cell 7.4v
4 screws  3M 20mm
4 screws  3M 8mm

You can access the presentation with animated instructions here (the image is a screen shot of the presentation).  Please be careful when using the LIPO battery and follow all safety instructions!

Step 10: Calibrate the Servos

Time to calibrate FOBO's servos.  This is necessary because the it is impossible for everyone to assemble the servos in exactly the same orientation.  So the calibration describes the unique servo offsets for a specific FOBO.  This allows every FOBO to use actions created by someone else. You can access the presentation with animated instructions here (the image is a screen shot of the presentation). 

Step 11: Let FOBO Roam!

Upload the navigation program to FOBO and let it walk around!

Step 12: Create New Actions

You can use the free Poser application to create your own custom animation sequences for FOBO.  Save the actions to file and share them with other FOBO makers.  The image is a screen shot of a step by step tutorial that shows how to use the Poser application to create a new action for FOBO.

Step 13: Program FOBO

There are more applications, such as controlling FOBO via a Kinect, available at the FOBO website.  As always everything is provided free and all of the hardware and software is open source.  Have fun and share your creations!

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