Design Of Hardware-in-the-loop Simulation For Small-scale Unmanned Helicopter

Small-scale unmanned helicopter has become an ideal unmanned aerial vehicle (UAV) owing to its unique characteristics such as taking off and landing vertically, hover flight, cruising as well as fast heading transformation. The research of UAV becomes a challenging work, since field trial for autonomous UAV development requires open space and is high-risk. In order to ensure the safety of the flight experiments, reduce development costs, and facilitate the verification and debugging of flight control, to establish a real-time simulation system for UAV become more necessary. Hardware in the loop (HIL) simulation can be used to test the UAV autopilot hardware reliability, the closed loop performance of the overall system and tuning the control parameter. Compared with the traditional testing methods, this method can fully test the product with a relatively low cost. Most of the HIL simulation for UAV is to buy X-Plane software. The commercial simulation software is not open source software and can not be modified for specific models. This paper introduces a Linux-base HIL simulation, which can be modified according to the model we are researching.By referencing to Raptor-90 UAV physical parameters obtained through system identification, and analyzing the relationship between the various parameters to obtain the other parameters we establish a mathematical model of Raptor-90. Based on accurate mathematical model, we adapt to multi-process structure, use C + + programming language to construct module of mathematical model of UAV, data fusion module, controlling input module, turntable control module, the target receiving module and graphical interface modules in Linux system. All of these modules constitute the HIL simulation platform.The simulation platform of a small-scale unmanned helicopter based on Linux system is set to greatly reduce workload, time-consuming , and cost of the experiments, while the codes of the simulation software could be installed in the autonomous helicopter system for debugging task as well. By comparison with actual flight, this system can well simulate the fight course and the result is agreeable.