Astronomy & Space Sciences

Title :

High speed self-bearing actuators

Area of research :

Astronomy & Space Sciences

Focus area :

Active MagLev systems


Executive Summary :

In the field of Space applications, the interest is increasing quickly for high speed actuators which can operate in several tens of thousands to lakhs of rpm. In order to maintain a longer life time for high speed actuators, Magnetic bearings are preferred instead of mechanical ball bearings. Using magnetic levitation to provide rotor suspension offers several advantages, including active control of rotor dynamics through variable stiffness and damping as well as isolation or cancellation of rotor vibration. Contactless suspension through magnetic levitation also permits higher rotational speeds, precision rotor positioning over the air gap, and operation without mechanical wear, thus reducing maintenance and carryingcosts. Traditionally, magnetically levitated motors useactive magnetic bearings (AMBs) for levitation and a conventional motor for rotation. A Self-bearing motor (SBM) integrates an AMB and an electric motor into a single device. In other words, an SBM is an electric motor that can simultaneously levitate and rotate a shaft. The major benefits of an SBM are compactness and economy. An SBM is more compact because of its reduced shaft length, yielding higher critical speeds and more stable operation of the rotating shaft. The aim of this project is to design and develop a Selfbearing motor to operate in 1.5 lakh rpm and deliver atorque output of 0.01 Nm. Motor is preferably a slot-less BLDC/PMSM motor. Drive Electronics has to bedesigned and developed for the high speed Self-bearing motor. Sensor-less control is preferred for the motor. Rotor position for levitation control can be obtained using eddy current sensors. The whole system should be power efficient and compact.


Shri Ravichandran MH, ISRO Inertial Systems Unit (IISU), Thiruvananthapuram

Organizations involved