Design of a cam and follower linear actuator for satellite optical systems

Abstract

Optical systems for satellites are used to image and track the physical environment of earth from space. Where the optical system images can be controlled through the rotation and movement of the optical system. Optical alignment is achieved though linear actuators, which constrain different degrees of freedom of the optical system. Optical systems require precise alignment, meaning the linear actuators that align them must have precise resolutions. During satellite launch, the satellite experiences both high acceleration and large magnitude vibrations, which can damage equipment. Common precision actuation methods cannot meet the high stiffness required for these satellite linear actuators. A cam and follower linear actuator was designed to fulfill these stiffness and precision requirements. Through modeling the dynamic and kinematic interactions between the cam and follower, a cam shape was designed, and necessary materials were chosen. Next through analysis of process capabilities of available fabrication tools, manufacturing methods for different parts were selected. Finally, using components designed for testing, kinematic tests were conducted on the linear actuator. Testing of the actuator demonstrated it was capable of actuating with a precision of 9.15 microns. More testing is needed to understand the stiffness of the device.