Matteo Ruzdijic
Placeholder cover image for the Custom Cycloidal Gearbox Robotic Arm project

Custom Cycloidal Gearbox Robotic Arm

CAD · Mechatronics · Ongoing

Role
Sole Designer & Engineer
Timeline
Sep 2025 – Present
Team
Solo project
Tools
Fusion 360, C++, Arduino, 3D Printing, Custom PCB/Protoboard Design

Designing a fully custom robotic arm around a self-designed 19:1 cycloidal gearbox built for high torque and low backlash.

The Problem

I wanted to design a robotic arm from first principles instead of bolting together off-the-shelf actuators. That meant engineering the gearbox, structure, and electronics myself, and getting real experience with high-torque, low-backlash actuation.

My Approach

I modeled every component in Fusion 360 with manufacturability in mind, and designed the 19:1 cycloidal gearbox for compact, high-torque, low-backlash actuation. I backed it with shear, bending, and torque calculations before cutting anything. On the electronics side, I wrote the C++ stepper motor control logic for an Arduino and hand-soldered custom driver boards on protoboard, then 3D-printed the structural parts and iterated based on how they actually performed.

Outcome

The project is ongoing. I'm currently developing the end articulator and its controller code, working toward a modular arm for pick-and-place tasks, demos, and other projects down the line.

Placeholder image: cycloidal gearbox CAD model
19:1 cycloidal gearbox, CAD model
Breadboard wiring for the shoulder and elbow joint stepper drivers, connected to an Arduino Mega
Breadboard wiring, shoulder and elbow joints
Placeholder image: 3D-printed arm segment assembly
3D-printed arm segments, test assembly