Terra Spider: Autonomous Remediation Robot

This project was designed and built by students in the Architecture program at the California College of the Arts; Manali Chitre (MAAD), Anh Vu (BArch), and Mallory Van Ness (MArch). The studio course was called Creative Architecture Machines (Fall 2014) and was taught by Jason Kelly Johnson and Michael Shiloh. Please visit http://digitalcraft.cca.edu/ for more information on this and other classes at CCA.

Project Concept:

Terra-Spider is part of a wireless robotic system capable of designing, repairing, and maintaining vast landscapes over extended periods of time. Taking inspiration from current farming and remediation practices as well as land art projects, this proposal rethinks the way landscapes are addressed. By programming each robot to understand the given site conditions, and equipping it with tools to remove and place bio-matter, it begins to take on a life of its own, creating patterns in and shifting the soil to best address the specific site’s needs. As a performance piece, each Terra-Spider is able to reveal a pattern currently hidden beneath the superficial surface.

This Instructable will show how to construct and operate the Terra Spider, capable of drilling through and placing materials along a path. This serves as a prototype to be developed into a larger, more complex robot that can be released on contaminated landscapes.

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HARDWARE:

XBee Wireless Components:

-SparkFun XBee Shield XBee Shield (WRL-12847)

-SparkFun XBee Explorer USB (WRL-11812)

-XBee 1mW Wire Antenna - Series 1 (802.15.4) (WRL-08665) (2)

Moving Parts:

-Power HD High-Torque Servo 1501MG From www.pololu.com

-SparkFun Micro Gearmotor - 90 RPM (6-12V) (ROB-12285) (2)

-Eurotool Pro-Electric Bead Reamer (for drill)

-Huhushop(TM) 12V DC DIY Dosing Peristaltic Pump

All Other Electronics:

-Arduino Uno

-Adafruit Proto Shield for Arduino Kit - v.5

-H-Bridge Motor Driver (SN754410)

-IC Socket - for 16-pin 0.3" Chips

-DROK LTC1871 Volmeter Didplay 3.5V-30V DC Volt Converter (2)
-Cutequeen Trading White 5050 48SMD 48-SMD LED Light

-N-Channel Power MOSFET F 12N10L (2)

-Juno Power NOVA BLOX 4000mAh External Battery (2)

-9 Volt Battery

Brackets, Supports, and Connectors:

-Alloy Steel Socket Head Cap Screws http://www.mcmaster.com/#socket-head-cap-screws/=v...

-1/2" 6-32 (30)

-1.25" 6-32 (5)

-1" 6-32 (5)

-Hex Locknuts 6-32 (60) http://www.mcmaster.com/#hex-locknuts/=v0waff

-Stainless Steel Washers http://www.mcmaster.com/#standard-washers/=v0w9cc

-Spacers (1/4", 1/2", 3/4", 1") http://www.mcmaster.com/#unthreaded-spacers/=v0wa...

-Actobotics Side Mount Bracket (pair) (ROB-12252) (8)

-Actobotics Servo Mount - Servo Plate C (ROB-12237)

-Actobotics Channel Standoff - Aluminum (Threaded) (ROB-12132) (6)

Material:

-1/8" Acrylic
-1/16" Acrylic

-7/8" Acrylic tube (interior dimension) to hold ink or biomatter

SOFTWARE:

-Rhinocerous (With Grasshopper and Firefly Plugins)

-ReacTIVision Version 1.5 http://reactivision.sourceforge.net

-Arduino 1.0.6 http://arduino.cc/en/Main/Software

Most of the Terra Spider is made out 1/8" Acrylic, however, to add strength to the legs and base, 1/4" acrylic is used. In addition, there are three parts that need to be 3d printed (we used a type A printer with PLA). These parts include the drill holder, extruder head, and gear track.

Using the 1/2" cap screws and spacers, washers, and lock nuts, attach the four pieces of each leg as shown. Be sure not to tighten the screws too much (each piece should rotate freely when connected).

Each gear box is made up of three gears; two large and one small. The two large gears need to be glued (using acrylic welding glue) to one circle on each side as shown. This will allow the gear itself to turn freely between the two exterior acrylic pieces. Tip: Use zip ties to loosely secure the components while you are putting them together.

The final bot should have 8 legs total. Connect them to the gear box with the 1" and 1.25" screws and spacers (longer screw on the bottom). Always place a washer between any two pieces of plastic you are connecting.

It may be helpful to do all of the wiring on the base before connecting the legs. The main components of this assembly are the Arduino Uno, rechargeable batteries, peristaltic pump, XBee wireless controller, and servo motor. See diagram above for how to wire each of these components.

These 3D printed components help the drill and pump run smoothly. The gear track is connected to the actual drill, which moves up and down in the drill holder. Many drills will work, however, we used a simple nail salon bead reamer (small drill) and replaced the dc motor with a high torque motor. We also replaced the sanding tool with an acrylic drill bit.

After attaching the top to the the robot, you are ready to make a fiducial marker to wirelessly track the terra spider through firefly. We cut several layers the exterior ring of the fiducial marker in order to fit a small LED light set within the marker itself. By using semi-transparent white acrylic for the base color of this component, we were able to create a nice, even glow. The glowing marker creates significantly more contrast, which allows the computer to more easily track robot.

In order to track the robot wirelessly, we first set up a white backdrop (on the ground) and centered the webcam three feet above this. By testing out only the dropping mechanism first, we were able to see that it was able to very accurately follow a path and drop matter within 5 mm of any specific point. Please feel free to use the attached grasshopper file to begin your own tests. Keep in mind that any pattern you input (for the bot to walk move on) must be a polyline with an endpoint at each location the bot needs to stop. There are several example paths in the file.

The bottom of each leg is designed to allow for feet to be attached in order for the spider to walk smoothly on any terrain. Feel free to design your own!