Simulation and Flight Test of a Temperature Sensing Stabilisation System

Thermopile sensors read electromagnetic radiation as a function of the object’s temperature. Because there is a temperature difference between the cold ground and the warm sky, these sensors could be used to detect the horizon and thus be used as a reference to stabilise a small aircraft, such as a UAV. To verify this hypothesis, a system has been developed that uses horizon detection using thermopile sensors to stabilise an R/C aircraft model. The aircraft has gone through a number of flight trials using remote control to enable and disable the stabilisation system. During the flight trials the aircraft was given various bank angles when the system was enabled. The stabilisation system was able to assume wing level under various bank angles and weather conditions with minimum overshoot and oscillation. Although the system shows good performance during flight trials, most of the design was done using trial and error. A design tool was needed to implement further improvements to the system and to efficiently implement it on other aircraft. This required a good understanding of the physical behaviour of the system and the interaction between the sensors, aircraft and the environment. A mathematical overall system model was developed and the MATLAB/Simulink toolbox was used to simulate the behaviour of the system under various conditions. The simulation results were then compared with actual flight experiments. This paper describes the modelling techniques used for the different system components and the results of the simulation compared to actual flight