Robotics: Part 1

This blog was initially started to post modeling builds, but after dealing with competitive robotics for about 5 years, I guess it's rather important to document what we did last time, that made robotics one of SM St. Patrick's main activities and source of pride. How we started and how we came to what we are now is an interesting, but long story, so I guess it's better to start off by describing the past few projects I was involved in, which were actually the first few robotics projects of the school. One note before I begin, though. Over the course of the past few years, various computer problems and hard disk crashes have caused some records and pictures to disappear, so I can only put out what I have left.

National Robotics Competition 2007 Open Category
Theme: Science Fiction Story
Main rules: 50% of the project MUST be lego, robot controllers must be Lego Controllers, i.e. NXT, RCX, Scout.

For the Sabah East Coast/State level, this was what we built:



I think the movie "Transformers" was released during 2007, so we decided to build one for ourselves. Out of the 6 of us, only me and Aaron had any sort of experience with Lego Mindstorms, but both of us were used to building small regular category robots using the RCX controller and Robolab 2.5.4 as the diagrammatic programming language. The NXT, its new motors (with internal rotation sensor), many parts and sensors were all very new to us. But we didn't care, we just plunged in and started building. We drew out various plans on how to transform, i.e. combine 2 seperate vehicles to one large robot, a truck folding in half and extending upwards to form a robot etc. Maybe because Optimus Prime was the main transformer in the movie, all of us wanted a truck to transform. In the end, due to the limitations of the robotics sets, we decided for a single vehicle with seperate, but connected modules, starting with the base of 3 parts:

Front Base(2 middle wheels were eventually deleted to enhance steering):

Rear Base:




The 2 front wheel bases were to be joined with a steering mechanism with a rack and pinion (pinion was driven by a worm gear connected to a motor) for the vehicle to turn:




Unfortunately, because there're 4 wheels in each front 'paws', the turning of the vehicle was a slow, gradual turn. We only found that out when we tested the robot after building, so we had to stick with it.

The front and rear wheel bases were joined with a railing with cogs on it:



To transform the truck into the robot, the front and rear base modules moved towards each other, folding the rails.



The base was simple, but that wasn't the case with the body. We wanted a body that can travel up and down the rails, so weight is quite an issue. The body needed to incorporate 2 arms with a few motors each, one with a metal sword, another with a shield, as well as a rotating head. This is what we did:


Motor 1 controls a shaft that rotates the head, motor 2 controls gears that move the body up and down the folding railing, motors 3 and 4 are sword arm motors, while motor 5 is to control the arm wielding the shield. Here's a hand for scale:


We kept the arms as simple as possible. Minimum number of gears and parts to cut weight. The sword arm had 2 motors, so that it could swing the sword through a large axis:


The arm holding the shield was a little more complicated, because it used 1 motor to move the arm up, as well as rotate the shield:


Mounting the body to the folding rail was an interesting task. We experimented with various motor layouts, gearings and guides for the gears so that they stayed on the track. As it turned out, the simplest solution, utilising small connectors to secure the gear onto the rack was the best:



And the body moved up and down the rail like a rack railway:


The head was a simple issue, because Lego supplied a head-like ultrasonic sensor with the NXT set. We gave it a helmet and some lego-decor, and presto! A head:

The whole body, with head, arms and sword (minus shield and chest plate):



The completed base with railing:

We added a few things to the base, including 2 touch sensors on the rear railing(with the green bricks) so that the controller can sense that the folding rail has completely folded.

Upon testing, we found out that there we numerous problems. The steering was sluggish, and the folding of the robot was nearly impossible. At that point, we did not have much time (less than a day left), so we just stuck to the theme of 'Transformers", while frankly, the robot did not transform much.


It's an impressive robot, though. It's just that it does not conceal itself.

During the competition, there were less than 10 competing teams in the Open category. The robot did not turn out as planned, but it was far ahead of the others, in terms of complexity, ideas and engineering. As a note of interest, most of the other competitors built vehicles: Trucks, cars, etc. Ours was unique.

During our presentation and demonstration of our robot, we managed to sell our robot to the judges pretty well. What they wanted was a project that had potential to improve and win in the national levels, and this project definitely fit the bill, outshining the rest. As a result, we won Gold award, i.e. first prize.

Today, after so many robotics projects and competitions, this robot still defines "Open Category" in my mind. We had little experience, but we rose to the challenge and delivered. This was the first time our school ever participated in the Open category. 4 members of our team, Aaron Tay, Alan Tiong, Jason Lee and Lee Joeshua had no prior experience with robots, and it was the first time me and Aaron Raj GC ever embarked on such a large project. Regular category robots that we usually build commonly utilised 1 controller, 2 motors and 2 sensors,with about 70-90 parts. This massive project utilised 3 NXT controllers, 9-10 motors, 5-6 sensors and 1750+ Lego parts. That's quite a difference.

A final team portrait, taken right after the competition:

Top, left to right: Jason Lee, Alan Tiong, Lee Joeshua (supporting members)
Bottom, left to right: Aaron Tay, Jia Wei (Me), Aaron Raj GC (main members)

That's all for now.