The Three G’s: Three Engineering Principles Applied in the Design of the Picky Eater

By Lucy C.

There are so many different concepts and approaches to engineering. The Nuclear Regulatory Commission, for instance, created a lengthy, sixty-eight paged presentation about a variety of different engineering principles, such as force, ductility, and elasticity, to name just a few. Meanwhile, different organizations and companies brainstorm and implement their own approaches to engineering. For example, the software company GitLab focuses its design processes on six core engineering principles: iteration, simplicity, reliability, quality, predictability, and velocity. Meanwhile, the nonprofit organization EngineerGirl implements acronyms and pithy statements like KISS (Keep It Simple, Stupid) and “keep the target user in mind” to look at engineering from a bigger picture perspective.

There are just so many ways to approach engineering!

Understandably, this can be quite overwhelming. It always leaves us with so many questions. Which approach should we use? Which concepts should we study, learn, and implement? How do we ensure we are learning and applying relevant material? Indeed, these are challenging questions to answer when we are given so many options!

This is why I have created a concise, bite-sized acronym to encapsulate some important hardware and engineering principles CAOS Robotics has applied in the design of the Picky Eater, a robot meant to intake, lift, and plunge cones down plastic poles in FIRST’s 2022-2023 Tech Challenge. This little acronym is called The Three G's.

Disclaimer: Please note that this acronym is only meant to be a starting point in hardware engineering, not an exhaustive review of all there is to know about engineering. Audiences are still encouraged to read this article and use it as a creative starting point, but they should not use it to replace a complete engineering education.

What are the Three G’s? Remember those fun little acronyms and mnemonics you used to remember facts in grade school, like Please Excuse My Dear Aunt Sally (PEMDAS) for the Order of Operations and ROY G. BIV to remember the colors of the rainbow? The three G’s is another one of those mnemonics. It represents three indispensable engineering principles that all begin with the letter G:

Gear mechanics

Gravity

Game strategy

1. Gear mechanics

A little gear can hold so much power. It can influence a system’s speed, force, rotation, and energy transference.

While designing the lift system for the Picky Eater, we had to ensure we selected and mounted the gears strategically in order to provide the lift with enough energy to move upward.

To do this, we utilized a simple yet effective gear system to provide kinetic energy for the lift. We decided to mount a smaller gear over a larger gear, then positioned our motor accordingly so that it would allow the smaller gear to revolve around the larger gear, providing energy for the lift.

We reasoned that this gear system would provide the lift system with optimal energy and efficiency; by allowing the smaller gear to revolve around a larger gear, the smaller gear would be given the entire circumference of the larger gear to revolve around, allowing it to provide more rotations per revolution to elevate the arm’s angle. Making a larger gear rotate over a smaller gear would have given the large gear a smaller path of travel, forcing it to travel more revolutions around the smaller gear’s circumference just to provide sufficient rotations to help lift the arm.

2. Gravity

Have you ever struggled to find the root cause of a complicated problem? We most certainly did while testing our robot.

While doing driving practice with our robot, we ran into some complications with our intake’s movement and control. We hoped for the robot’s arm to smoothly and seamlessly move up and down whenever necessary. Instead, however, the intake’s arm was shaky and spasmodic whenever we tried to move it, hindering seamless lifting and angling.

We initially struggled with finding the root cause to this problem; could the spasmodic movements of the intake be caused by problems with the hardware or problems with the software?

On one hand, there could have been some potential software complications associated with the robot’s movement data, given that the code had previously been modified to accommodate some mechanical changes we made to the robot. However, we used the concept of gravity to deduce that problems with the hardware were most likely the cause to those coordination issues.

Our captain concluded that the intake’s extension was forced to fight gravity whenever it moved. The extension was relatively small and thin, making it probable that its structure may not have been large enough to remain stable and support its own mass whenever it moved. Additionally, we noticed that the more the intake moved either up or down, the more unsteady the structure became. This might have indicated that the small structure may have struggled to handle the downward pull of gravity while moving up, explaining its quivering motions upon moving up. Meanwhile, when the force of gravity was drawing the intake toward the ground while it was already being plunged down by a human driver, it made sense for it to shake due to all that downward force and motion.

From there, we learned about how important it was to create stable hardware structures in the field of robotics.

3. Game Strategy

Not only did we have to remember and apply some hardware concepts to facilitate necessary design decisions for our robot, but we also had to make strategic decisions to ensure our success in our 2022-2023 season at FIRST.

During that season's competition, we decided to take a methodical and collaborative approach to our game strategy called scouting. This is where FTC competitors visit, study, and communicate with other teams in order to select an alliance partner, a team whom they will collaborate with throughout the competitions in a competitive yet mutually beneficial way.

To do this, our team developed a “Scouting Sheet,” which consisted of a variety of different survey questions we posed to other teams about their robot’s hardware, software, strengths, flaws, etc. This sheet would inquire about the teams' basic aspects of their autonomous code, teleoperated programming, and game strategy. We would in turn do the same thing. This would allow us to exchange ideas with fellow competitors while brainstorming potential alliance partners to work with during the competitions. After brainstorming and swapping ideas, we would then select an alliance partner willing to collaborate with us during competitions and use our knowledge about one another’s strengths and weaknesses to strategize a collaborative and mutually beneficial approach to a certain competition.

To conclude, the Three G’s were immensely helpful when it came to designing the Picky Eater. Gear mechanics, gravity, and game strategy were all paramount to developing our hardware, solving mechanical problems, and approaching our 2022-2023 competitions strategically. While the Three G’s do not encapsulate the complexity entirety of all engineering principles, they were still a great start to brainstorming our design.