Trevor Hocksun Kwan

An air bearing table for satellite attitude control simulation

Attitude control of a spacecraft is critical for its operations, but at the same time poses a significant challenge to control engineers due to the non-linear behaviour of attitude dynamics. Hence, a physical ground testing platform for space-craft attitude dynamics and control is essential for verification of a control algorithm prior to its airborne application. In this paper, we present an air bearing based simulation platform which, unlike previous air bearing table designs, is small in size so that it can simulate the behaviour of smaller (nano) satellites such as CubeSat. Currently, the air bearing table is capable of unrestricted motion about the yaw axis and we demonstrate this by the implementation of a closed-loop yaw angle controller. However, gravitational torque prevents us from achieving a simulation about the pitch and roll axes, which should otherwise provide us with up to ±60 degrees of motion. Subsequently, an automatic counterweight system is currently being constructed to overcome this problem, and its governing algorithms are presented herein.

A Parametric Study and Optimization of an Air Conditioning System for a Heat-Loaded Room

Optimization of an air conditioning system is critical in terms of the transient and steady state behavior of the air distribution along the room and the temperature of the equipment themselves. In this paper, three computational techniques, namely, the standard , RNG , and the model, are used to numerically simulate and determine the air distribution in an air-conditioned room. The simulation results for all three methods are verified via a comparison with an experiment involving a room that contains a computer server which generates up to 6 kW of heat. In doing so and by additionally performing an error analysis, it is determined that the model produces the most accurate results. The results also indicated that the direction of air supply from the air conditioners has a strong impact on the velocity field and temperature distribution along the room and on the computer server. Hence, many candidate directions of air supply options were selected for study and by conducting a performance evaluation in terms of air temperature around the server, the optimal solution was obtained.