Don't Just Build, Sustain: Why Reliability is the Ultimate Scoring Tool

By Sriyangsh Datta

Hey FIRST Tech Challenge teams! Robots can wear out very easily, especially after many matches. This is why having a reliable design is an important part of testing your robot. Reliable design means engineering your robot so that it performs its tasks consistently and predictably, without breaking down during crucial moments such as exhibitions or matches. We make designs reliable for one simple reason: a robot that constantly needs emergency repairs in the pit can't score points on the field. You can make a design reliable by keeping your mechanisms as simple, sturdy, and protecting your wiring.

As a fellow FTC member, I can tell you that reliability is quantifiable, engineers don't guess if a robot is working; they use math to measure it as a percentage of success. To test long-term reliability, engineers use something called "accelerated life testing," where engineers might run a robot arm back and forth continuously in a lab for days to simulate an entire season of wear and tear in just one week. However, it is a golden rule of engineering that reliability is never permanent. Due to friction and stress, every single part has a lifespan and will eventually break. That is exactly why your team needs a maintenance schedule to inspect the robot and replace worn-out gears or stretched belts before they snap during a match. For example, there can be routine bi-weekly maintenance checks to test the robot in all aspects.

While FTC robots mainly compete safely inside school gymnasiums, real-world reliability engineering means protecting robots from a massive, brutal list of environmental and external impacts. We constantly design against mechanical impacts (crashing into obstacles) and mechanical fatigue (materials slowly weakening and snapping after bending thousands of times). If a robot is designed for the outdoors, we have to seal it against weather like heavy humidity, water spray (like rain), and even extreme water depth and pressure if it's an underwater drone. We also choose special metals and coatings to prevent corrosion (rust) and use tough plastics to prevent damage from the sun's UV radiation. Finally, we have to test for extreme environments, like drastic or cyclic temperature changes (going from freezing to boiling over and over, which makes metal expand and shrink), and even unexpected chemical reactions. Did you know that the chemicals in everyday items like perfume or hand lotion on a human operator's skin can actually dissolve and ruin certain robot plastics over time? Tests on systems and mechanisms allow for the discovery of this and a further improvement to the product.

Overall, reliability testing is very important to ensure robustness of operation of a robot. Various tests help us mimic real life conditions to understand how we can design and fix our robots for successful run in FTC as well as in the industry. Recently, JavaJuice co-hosted an event to learn more about how to design keeping in mind several factors related to reliability. This event was attended by 6 FTC and 4 FLL teams and 60 attendees.