This is an old revision of the document!
“TBD” - Generator’s Totally Badass Dragon Champbot Entry
June 23, 2016
Summary of Project
The TBD team is asking for $500 of member money to build a remote controlled swimming robot, aka Champbot, for the competition at the Champlain MakerFaire in September 2016. Description:
A highlight of the Champlain MakerFaire is the champbot competition. Contestants build a swimming robotic lake monster to navigate a course of buoys; the winner is the robot with the fastest time through the course. Contestants can increase their scores by adding any or all of the following challenges: putting an object in a target, submerging, lighting a target on fire, and being entertaining or visually interesting. Design:
The two sketches below show the preliminary design for the basic functional parts of Champ, namely a frame, propulsion, and battery location. Not shown are any control elements, decorative features, or anything relating to the optional challenges. This design is intended as a “mule,” meaning a device for testing basic functionality, but not necessarily reflecting a final design or configuration.
Some features of this design include:
Flotation elements (large green tubes and orange frame) are made of pvc and are completely sealed. They contain no electronic or mechanical components, no perforations, and hence should not lose buoyancy due to leakage. Leakage has been a big problem in recent competitions.
Steering is entirely by thrusters placed wide apart for maximum leverage. Rudders are less effective at low speeds or close maneuvering, and work poorly in reverse. The final design will probably have additional thrusters.
The battery will be placed low, and should help keep the craft upright in a windy environment. Wind effects have been a big problem in the past. The frame offers little resistance to movement through the water.
Benefits to the Generator
We believe this project benefits the Generator community in many ways:
Glory, publicity for the Generator. The MakerFaire is attended by thousands of people, many of which watch the event. Note the potential for public embarrassment does also exist.
An enjoyable project for the participants.
If successful, a model for how to develop a good community project.
Skill building among the community. Some of the technologies required are not well known.
Workplan and Schedule
A basic timeline is shown above. (We also have a more detailed schedule.)
The basic concept is that we will not at first attempt to build an “A+” robot. There are too many unknowns and technical challenges to make that a successful approach. Instead we plan to build a basic robot to test basic functionality: flotation, propulsion, stability, control; we will do this quickly. We will gradually add enhancements to our basic design based on lessons learned. Hopefully this can result in a very good robot by the end of the process.
The total cost is estimated at about $500, as follows:
PVC and related fittings $75
Drive motors - RS550 @ $14 28
Drive motor controllers @ $21 42 (range is $20-$60)
Batteries @ $64 128
Radio setup borrowed
Other motors 25
Other controllers borrowed
Decorative features 75 (unknown at this point)
Devices for optional challenges 100 (unknown at this point)
$523 (round off to $500)
To the extent that we can find salvaged supplies the cost might be reduced. To the extent that we experience “false” starts and need to backtrack, the cost may be greater. All participants are willing to put in some personal funds.
Note that substantial prize money will be awarded - $2,500 for first prize and about $5,000 in total. It is not entirely impossible that we could be one of the winners. If so, depending on the prize amount, we would expect to return the Generator's investment, with possibly some stipend going to the participants.
A group at the Generator is meeting to design and build a champbot. Jim Wick, who has lead many first robotics league teams to success, is coordinating this project. Participants include Daryl Stultz, Cameron Stultz, Brook Martenis, Jake Blend, Lars Hasselblad-Torres, Isabel Hasselblad-Torres, and Leisa Fearing. Progress So Far We have already done some testing:
Test of a motor and propeller combination. The RS550 motor and 2“ propeller seemed to give good thrust during a “bathtub” test. We discovered that this motor is capable of running directly in the water with no protection and no apparent damage.
Test of flotation. The two 4” flotation chambers have the buoyancy to support a large, heavy, lead-acid battery with plenty of capacity to spare.
We glued together the basic chassis for the “mule.” It is complete.
We received two RS550 motors and two 60 amp motor controllers. We tested these. We are able to control a motor from a wireless joystick. Runs fast, slow, forwards, backwards. Controller operates directly from the RC signal without the need of a microcontroller or programming.
We are committed to this project and are making good headway. This is the kind of project that builds community, increases member skills and raises Generator’s visibility in wider community.