actuator selection is one of those things that looks deceptively simple until you actually have to build the machine.
when we first started working with geared motors, wiper motors were our immediate pick. they were a pain to work with from the get-go, but as FAMA grew in size and complexity, we needed more torque and had few other options.
at the time, we moved to a 12 V architecture and used four geared wiper motors, one at each wheel. each motor was rated at around 60 W, giving us 240 W across the drivetrain. with roughly 8 Nm of output torque per motor, the four motors gave us about 32 Nm of combined wheel torque. with our 22 cm diameter tires, that translated to roughly 291 N of theoretical tractive force at the ground. for a robot weighing under 50 kg at the time, that was enough to get us moving.
on paper, everything looked good. we had the torque, the power and a robot that could actually move. we thought we had finally figured out the actuator problem. then the real problems started biting us in the ass.
we kept blowing motor controllers. the motors were inductive loads, and rapid current changes during PWM switching and braking produced large voltage transients from back EMF and the energy stored in the motor windings. our early boards weren’t designed to absorb those spikes, and components kept failing.
a lot has changed since then, but those were some hard lessons to learn!
throwback to when we had our very first real-world test with our 5th FAMA prototype in 2022. this was our very first ever build with metal, and it was scrappy as hell, but it gave us a platform to finally put our autonomous driving stack to the real-world test.
for months, we were locked in a garage figuring out how to deal with metal: welding, cutting, grinding, riveting, etc. the funny part was that we were still software engineers with basically zero experience building anything in the real world. we knew getting it right on the first try wasn’t possible, so we aimed for smaller goals with each prototype, rapidly testing, breaking, learning, and scaling from there. i still remember watching youtube videos on how to weld.
we went through several prototypes, learned a ton, and gathered massive amounts of field data that shaped how we thought about FAMA and its ability to understand and operate in the field. that period completely changed how we approached product development. we became obsessed with field testing because we realized the fastest way to get better was to put something into the real world, see what broke, learn from it, and build the next version better.
looking back, those scrappy days taught us a lot about engineering, resilience, and building with almost no idea what we were doing at first. we were just determined to prove that our idea could work, so we had to learn everything on the fly and keep going.
a lot has changed since then, but those years of prototypes, failed tests, broken parts, field experiments, and endless iteration are still baked into how we build today.
i lowkey miss the scrappy hacking days :)