Mechanical Design
The major components of the robot's mechanical structure can be broken into 3 main parts:
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The Chassis & Drive System
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The Collection Arm
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The Zipline Mechanism
In order for Indy on the Rocks to do anything, it first must learn to move. The body in which it moves in is the Chassis, while the mechanisms which it moves is the Drive System. These two components were our first priority to complete.
During development, we realized we needed a quick physical model to brainstorm the kind of space we had. Thus, to begin with, a copy of the chassis was constructed entirely out of cardboard. This allowed us to visualize the available space for further designs.
Once we were content with our layout, we proceeded to manufacture the real Indy on the Rocks out of steel. We used a waterjet cutter to cut out the body, which was then folded into shape.
Chassis & Drive System
After the chassis was complete, we set out to make it follow black electrical tape. This is the method it would need to navigate through the Temple of Doom.
Below, watch a demo of our Tape Following:
In the competition, robots score points by first collecting artifacts (1 point each) and the Idol (3 points), then successfully bring them to the Starting position.
The artifacts and the Idols are small, 3D printed figurines with a magnet on top. These allow for a variety of ways to collect them.
Originally, we had planned to use electromagnets and solenoids to attract magnetic artifacts. However, our Electromechanical Integration expert, Kevin Multani, researched such a possibility and realized that a solenoid simply does not have enough strength to lift the item from ground.
Therefore, we reconsidered our options and designed a new collection system: an arm actuated by a large servo, holding a small 'retriever' arm, which swings down with a piece of iron to magnetize and pickup the item, then retracts to pop the item out.
Mechanical Lead, Ben Mattison set out to turn this idea into a reality. Within days we had a fully functioning collection system. This system remained with us until Indy on the Rocks' final form.
Check out the video below to see it in action:
Collector Arm
Zipline Mechanism
Theoretically, at this point it is possible to complete the challenge by turning around and driving back. However, we were an ambitious team from the start, so when we heard about the Zipline escape option, we decided to go for it.
The design of our Zipline Mechanism is, in many ways, the defining trait of Indy on the Rocks. We wanted it to reflect how the real Indiana Jones would escape: with a rugged lasso and wicked panache. What we came up with was a unique two-part mechanism for riding the zipline: first, a deployment arm swings a carabiner upwards; if it misses the zipline, the robot moves backwards to correct itself; if it hits the zipline, the carabiner detaches from the deployment arm and falls onto the zipline; next, a winch pulls the carabiner via a leather belt, lifting the robot up off the ground; finally the 3D printed spool on the carabiner rolls freely to let Indy on the Rocks swing home. The key concept is that the deployment onto the zipline is separated from the winching onto the zipline.
Once again, Mechanical Lead Ben Mattison led the development of this mechanism. Within a week, Indy on the Rocks was able to go home from the rockpit.
Hard to believe that a robot can be so acrobatic? Maybe you should see it in action yourself:
