Wire Gear for Small Rotary Actuator intended for Low Earth Orbit Applications.

Abstract

In this master thesis, a small rotary actuator with wire driveline intendent for space solutions is developed and tested. The replication of the environment with focus on surface friction, surface roughness, and more dynamical related features are considered. Features like temperature, vibration, radiation and more are excluded to limit the size. This because the field of interest in this iteration is to see if a wire driveline can replace traditional gear transmissions for small rotary actuators in the future related to the simplest dynamical operational environment. During this thesis a small rotary actuator was developed. The actuator was designed, so that angular rotational friction is represented in a feasible way, gear ratio accordingly to torque and power requirement and finally representative surface roughness and sizing as desired. In addition, the wire driveline was implemented in the most feasible configuration with a preload mechanism and a load cell to monitor tension in the wire related to slack in the wire. Component and lifetime tests show that the actuator works satisfactory and represent the desired environment. The following half time result was obtained: The wire tension seems stable and minor degradation of the wire is noticed after 600.000 cycles of 0-180-0 deg.