Development Of Driving Device For Space Environment

In the high vacuum and microgravity space environment, the temperature of an object surface will be increased drastically when it under sunshine directly; and that will be decrease to extremely low when it in the shade. Due to the limit of Curie temperature effect, motors based on electromagnetic theory cannot directly adapt to extreme temperature in space. This study adopts the methods of radiation isolation, heating device, double layer of walls and phrase change material within walls, to control the temperature of the inner room of the box for step motor and other electronics components. The device included gears, angle sensors, temperature sensors to drive the thermostatic valve in EVA spacesuit to positions controlled. This system has experienced high and low temperature vacuum tests, and successfully applied in the EVA spacesuit simulated flight tests. The detail works of this thesis listed in following points.According to the requirements of thermostatic valve operation, three plans of the mechanical structure of driving device were designed and compared. The step motor, gearbox and a partial gear to drive the thermostatic valve handle to positions needed was selected in this application. Meanwhile, a single chip microcomputer and touching screen constructed the main control system.Mechanical transmission system between temperature control valve and motor was designed, and gear surface contact fatigue strength and tooth root bending fatigue strength of every gear were checked. Also, a protective structure for step motor and sensors was designed. The protection box was constructed with double layer walls and paraffin filled within the walls to absorb the heat, and hence avoid the box over heat. Actuators outside the protection box were made of temperature enduring and heat isolating materials.A three-D model was established by software Inventor, and introduced to Fluent to simulate their heat transfer characteristics, and temperature distributions of the temperature control box was analyzed.Software to operate the step motor and control the temperature was designed. An operation manual for the system was revised. Based on the development, experiments under various environments include simulated space environment was carried out. Temperature within and out the protection box and operation of the actuators performance were recorded. The experiments validated the development.This study developed the thermostatic valve operating system for the requirements of the spacesuit thermostatic valve operation. The driving device can be operated normally in space environment. The study provides a new idea for space robot development and other electromechanical devices to be used in space.