| Research Abstract |
In recent years, multirotor helicopter type autonomous UAVs are being used for aerial photography andaerial survey. In addition, various applications such as buildings maintenance, security and rescue are expected in multirotor helicopters. Not so distant future, these technology will be penetrate in our life. However, serious accident could occur if became widespread without guidelines and guarantees of safeness. Therefore, manufacturers need to be able to show that region of applicable application and behavior of fault mode to users. To show that, analytical model that can be used for analysis of behavioron model parameter change and hardware fault is needed. Our research group has started research onmultirotor helicopters since 2007. In 2010, we started to develop a practical multirotor with own design. Our research goal is to achieve advanced network system of ubiquitous small-scale aerial and groundrobots for high performance prevention of disaster in this project. In 2011, we suc
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ceeded in autonomouscontrol and we launched a consortium of multirotors in 2012. As described above, analytical model is needed for realizing safe multirotors. In this research, we constructed an analytical model which can beapply to general multirotors. The model was verified in experiment by constructing a control system. We constructed a simulation system which can be use for operator training and control system validation. Inaddition, this simulator can be simulated rotor failure and sensor failure. Actually by using this simulator, we showed that our simulator is useful for analyzing behavior of rotor failure, and is useful for training anoperator. While the multirotor helicopters are mainly used in outdoors, also it is expected for informationgathering in indoors. Autonomous navigation of flying robots in GPS-denied environments such as indoors requires that the the flying robot be able to estimate the position using external sensors. While laser scanners are mainly used for studies of indoor flight, development of smaller size robots is prevented due to the larger mass of sensor. Thus in this study, we develop a lightweight flying robot forachieving indoor autonomous flight using four infrared (IR) sensors. However, following problems are exists in localization based on IR sensors. First, it is difficult to use IR sensors close to a wall, because doing so would yield faulty results when calculating distance using the sensor output voltage. The secondproblem is that the spatial resolution is low because only four IR sensors are used. For the first problem, we constructed a probabilistic model of IR sensor that can be estimate position from voltage informationwithout the use of calculated distance. The second problem, was solved by rotating the robot horizontallyat all times to acquire information from various directions. Finally, the localization performance wasverified experimentally using an electric turntable and a cart. In the experiments, we confirmed that localization is successful even when the robot is in motion and even when the robot is flying near a wall. Less
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