warbot1

 

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This is  our first warbot design

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View of  the business end including the ramming bar and drive train

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Undercarriage  view

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Close-up of the rear wheel assembly

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The remote control pendant assembly

We spent a lot of time recently watching the robots battle on late night cable television. It is interesting to watch these highly technical creations tearing each other apart by whatever means possible. It occurred to us that we could have our own robot war right at home using our two Lego bricks.

This one was our first design. It is made entirely using pieces from the Lego Robotics Invention set. We wanted to design a robot that had some possibility of staying in one piece when fighting opponents of similar size and capabilities. Just as in the case of the televised robots, we wanted this one to be human controlled instead of autonomous. We also wanted to use the least amount of pieces while having a sound structural design. Less pieces meant less to fall off during a battle.

Two long structural members were attached to the RCX brick using pins. Then extensions were added at each end using the black pins, one for the drive train assembly and one for the rear wheel assembly. The two transversely mounted motors are attached directly to the frame extensions and rest against the RCX brick for additional support. The axles also go through the frame extensions and each is  independently driven.

The rear wheel assembly is freely rotating and is held in place with a long axle. The axle is kept stationary with two gray supports. Refer to the close-up photograph below. The frame extension must be far enough away from the RCX brick to allow this wheel assembly 360 degree rotation.

The ramming bar assembly consists of two long structural members held in place by flat pieces perpendicular to the bar attached directly to the frame. Extra support was added to both the top and bottom of the robot to assist in keeping this bar rigid, straight, and most importantly, attached.

We reused the pendant control design from the Useless Bot project. The two lever arms contact the touch sensors. When the touch sensors close, the wheel for that side moves forward. each lever arm is held open by a small rubber band.

>The survival strategy for this warbot is to ram its opponents. It needs about 18 inches to get a good flying headstart. The low center of gravity makes it difficult for a slow moving opponent to easy flip it onto its back. Most of the assembly is rigid and reinforced, making it more difficult for an opponent to disassemble this model by ramming or tearing. The only two immediately apparent weaknesses are the lack of rigidity in the rear wheel assembly design and the inability to back up -- the robot can only turn or move forward.

Our next step will be to design and build several warbot opponents and then have the different designs battle each other to find out what works and what doesn't.