Building an electromagnetic spherical robot

Electromagnetic Spherical Robot Project Team Picture

Joshua Bauman, Lucas Henderson, Kristopher Kirkwood, Logan Underwood and Levi Varsanyi

Degree:
- Bachelor of Applied Science
Program:
- Engineering Physics
Campus: Vancouver

Our project

Although many capstone projects focus on a specific use case and application, we wanted to pursue a project where the potential applications were of secondary importance to our desire to grow our knowledge of fundamental physics, gain experience applying magnetic circuit theory, develop power electronic systems and implement advanced control algorithms.

We came up with the idea of building a spherical robot that could actuate itself and move along a ferromagnetic surface using electromagnets configured inside the ball.

Our goal was to be able to move and direct the sphere by turning on different electromagnets in different sequences.

Our design solution

Each of our 20 magnets is mounted to the inside of the shell and paired with its own custom printed circuit board that drives current through the electromagnet. These actuator modules are powered by a central board that is connected to two internal batteries. That same central structure also holds the ESP microcontroller, which runs the control algorithm and sends signals out to every magnet board. Because the sphere is built from two completely modular halves, each side mirrors the other.

We built the entire system from scratch, including designing and manufacturing the electromagnets and control circuits and 3D printing the shell.

Diagrams showing a spherical robot design with internal components, control loop, and information flow.

Technical diagrams of electromagnet design, control system, and magnet selection process.

The technical challenges we faced

One of the biggest technical challenges was determining how to reliably control the sphere’s motion. We assumed that, in principle, we could activate specific internal magnets to drive the ball in a given direction, but that only works if you know where those magnets are as the ball rotates.

Once we solved that, we had to design an algorithm that could decide which magnets to activate, and at what strength, to produce the desired velocity. This required integrating data from an inertial measurement unit, applying filtering techniques to clean up the signal, and then building the control algorithm and software architecture to integrate it all.

Another major challenge was identifying how to physically fit and organize all the components inside a completely wireless spherical shell. We have 20 magnets inside a 3D‑printed shell, and each one needs its own dedicated driving circuit.

Designing an internal structure that could hold those magnets, their individual boards, the batteries, and all the wiring took a lot of design and thought. We also wanted the entire assembly to be spherically symmetric to keep the system’s behaviour predictable, but achieving that symmetry while accommodating so many components was far from straightforward.

How our design progressed over two years

In year one, we focused mainly on magnet design. Knowing that we needed the magnets to be as strong as possible, we derisked our project by focusing on making an electromagnetic disk that spun along one axis. We invested considerable time designing and building a test stand to measure the force generated by the magnets, and then used this information to select a magnet shape optimized for strength and weight.

In 2025/2026, year two, we split up the work based on our interests and areas where we wanted to gain more experience.

What’s next for this project

Although our sphere moves in response to our control, it does not move as quickly as we had hoped, primarily as a result of its weight. Our final project report outlines a series of recommendations, including using higher capacity batteries, implementing advanced magnet activation algorithms, increasing the number of magnets, using improved magnet materials and exploring sheetless propulsion methods.

What we’re most proud of

We are proud of the progression we’ve made from an early idea to a fully functioning system we can hold in our hands.

Each part of the project went through multiple iterations, whether it was the driver boards, the software architecture or the electromagnets themselves. The first magnet we tested was probably six times weaker than what we have now.

If you look at the boards you can see the evolution of a progression of design choices. It all comes together into one system with each of the layers—physics, electronics, software and mechanical design—integrated in a system that is easy to control with a joystick.

Over the course of this project we have learned a significant amount about magnetism, including how magnets of different materials and geometries perform, as well as how electronics interact with these magnetic fields and the interdependencies that emerge between the two.

Finally, this project has reinforced the importance of integration. This project draws on many different areas of science and engineering, and they all need to work together. Effective engineers are confident working in – or coordinating with – multiple domains to achieve complex project goals.