Implementations relate to a brake mechanism for a spherical wheel. In some implementations, a wheel mechanism includes a spherical wheel and a base coupled to the spherical wheel via a rotary bearing contacting a surface of the spherical wheel, where the rotary bearing is configured to allow the spherical wheel to rotate. The wheel mechanism includes a brake ring coupled to the base and configured to selectively engage and disengage the surface of the spherical wheel, where the brake ring provides friction opposing rotation of the spherical wheel when engaged.