| Unmanned helicopter, with unique flight characteristics of hovering, taking-off and landing vertically, is of great potential applications in military and civil areas such as reconnaissance, aerial photography, rescue and so on. MUH (Mini Unmanned Helicopter) has been a most often-used platform by research team on helicopters, also very popular in model fans, owing to its low cost and more flexible flight. Attitude augmentation system for MUH can ease the tension of the remote controller by reducing attitude sensitivity and helping to maintain MUH on the horizontal level. However, the present available augmentation systems are either high cost or weather dependence. Thus, the research for a low-cost and independent attitude augmentation system is of great necessity to the promotion of MUH application.This paper designed and developed a hardware platform adopting a high-efficiency and high-accuracy converter to supply both operating voltage and standard voltage, an inertial measurement unit with gyros and accelerometers as feedback unit to measure horizontal attitude, and a micro-chip controller as the central processor. All these work helped to cut the cost of the system.Secondly, this paper designs horizontal attitudes determination based on gravity adaptive complementary filter, fuses both angular rates and the measurement of accelerometers to get gravities attitude determination. This algorithm cuts the drifts of gyros and motion noise of MUH to an acceptable level. By this way, the low-cost system ensures stable performance and independence on the term of attitude feedback.Finally, this paper selects fuzzy PID control as the attitude augmentation scheme according to the research and simulation comparison, which is suitable for the system with no accurate model and only micro-chip controller. With the ECCPM de-coupling done, the paper designs a ground station for confirmatory experiments. The data of experiments shows that the augmentation system has a satisfactory performance.
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