One can argue that the solution where they add a 4th gimbal to the stable platform to avoid the possibility of a gimbal lock is kinda-sorta a mechanical equivalent for a quaternion. See for example the famous exchange between CapCom and Apollo 11 Command Module Pilot Michael Collins:
https://space.stackexchange.com/questions/30953/did-michael-...
But when I wrote that really all I meant is that it is advised to use quaternions to represent the attitude information in the software which fills the gap between the sensors and the actuators.
But when I wrote that really all I meant is that it is advised to use quaternions to represent the attitude information in the software which fills the gap between the sensors and the actuators.