A miniaturized two-DOF rotational gyro with a ball-joint supported permanent magnet rotor

We proposed a miniaturized two-degrees of freedom (DOF) rotational gyro with a ball-joint supported permanent magnet rotor. The structural design and the dynamic model of the gyro are presented and analyzed in detail in this paper and testified by preliminary experiments. When the rotor tilts away from its null position, it will be constrained by a contactless magnetic equivalent elastic torque derived from the driving structure. As a rotational gyro, this structure is very simple and small, with a core size less than 6 cm³, and it needs only 0.75 W to keep the rotor spinning at a speed of 15 000 revolutions per minute (rpm) in a standard air pressure condition. Preliminary measurements show that, at 7000 rpm within a full scale of ±100 °/s, the gyro has a scale factor of 18.69 mV/(°/s), and a nonlinearity of 0.33% is also achieved through calculation. The results show that the gyro can be used to measure two DOFs' angular rates of carriers without close-loop control due to the existence of magnetic equivalent elasticity.