Large stroke Rotary Voice Coil Motor for cryogenic application

Inhalt:
CTEC is developing and testing Rotary Voice Coil Motors (RVCM) for new cryogenic space scan mechanisms applications, based on former MTG space program heritage. The RVCM is an electromagnetic motor based on Laplace force. The motor is composed of coils at the rotor part (mobile) and magnets at the stator part (fixed). The Laplace motor generates a pure torque, without cogging or parasitic force drawback, which makes it specifically relevant for scan mechanisms. For the expected next generation of scan mechanisms, CTEC has been asked to extend the angular stroke of RVCM technology up to ± 90 deg, and to make a specific design for cryogenic temperature condition at -140 °C. The design and test results are presented, up to a torque of 1.2 N.m. The functional tests are presented at ambient temperature and pressure, as well as in the operational temperature range [105 to -140 °C to °C] under vacuum. The goal of this paper is to present the motor that meets these requirements. The first part will focus on the approach that leads to the selection of the architecture and magnetic materials. It will point out on the main issues that are the torque characteristic and the power consumption. Then, the actuator by itself will be presented, associated with the expected performances. To conclude, the test results of the prototype will be summed up.