Hardware-In-Loop Simulation Development

Abstract

This work describes the development of a hybrid simulation environment to be used in order to assess the performance of a satellite launcher control system. The hybrid simulation program starts from a digital simulation program that digitally simulates the complete system, that is, the on-board computer with the control laws, the vehicle dynamics, the actuators dynamics, and the sensors dynamics. The digital program is then broken into two simulation programs, one that simulates the on-board computer with control laws and another that simulates the rest of the system. After validation of these two programs, the hardware interfaces are then included. In this case, the ADC (analogue-to-digital converter), DAC (digital-U<analogue converter), and 1553B interfaces are included. After a new validation, the real actuators are included in the system, and finally, the real sensors are included. So in the final phase only the vehicle is simulated digitally, and as this is the most real condition possible before the actual flight, it represents the best condition to assess the flight control system performance and to detect possible problems not clear at the design phase. Finally, comparisons of the system response in each phase are shown in order to give an idea of the differences between each phase. The work mainly describes the method used in order to obtain a very reliable hybrid simulation environment for a satellite launcher.