**4.2. AUVs' attitude simulation and experiment**

**Figure 9** shows the whole system of the TrenchRoDer equipped with the proposed AIRS. The whole equipment includes the TrenchRoDer, a camera, an AIRS, a Bluetooth box, and a floating board. We put a camera in the waterproof bags and tied them to a fixed plate in order to observe the situation when the airbag is inflated. The function of the floating board is to protect the Bluetooth box from immersing into the water.

**Figure 8.** The calibration results from the static condition produced by the SCEKF processing. (a) Roll angle calibration. (b) Pitch angle calibration. (c) Yaw angle calibration.

Design and Estimation of an AUV Portable Intelligent Rescue System Based on Attitude Recognition Algorithm http://dx.doi.org/10.5772/intechopen.79980 61

**Figure 9.** The TrenchRoDer equipped with the proposed AIRS.

In order to construct a robust underwater vehicle fault attitude database, we simulated the underwater vehicle motion model with different situations in the water environment, which can provide the particular case of attitude data, such as if the AUVs suffered a crash or a disabled propeller. Moreover, we built the fault simulator GUI interface for a more convenient operation, in other words, the AIRS starts with the fault simulator GUI interface, after inputting the required AUV's dimensions, hydrodynamic coefficients, buoyancy center, and inertia coefficients. Next, the simulator calculates the different AUV motion data under different cases through the Matlab™ program as shown in **Figure 10**. The above results from simulator will combine with the experimental data as the database for the training and verification of BPN classifier. Last but not least, the real AUV motion signal is set as the testing dataset to ensure the establishment of the AIRS. The modular modeling equation of AUVs is selected from [28]. The modeling method of Prestero's which id without considering the sea conditions of emission can help us to generate the dynamic models of AUVs quickly and conveniently. The dynamics model and kinematics model of AUVs are established by analysis of the force working on AUVs moving underwater, based on the theorem of the momentum of the rotation around the buoyancy center and the theorem of the motion of mass center. The motion in 6-DOF of the AUVs is determined. And then, the attitude data of AUVs at any instant are determined.

Since we simulated the AUV motion in the underwater environment without considering the influence of currents and waves, we did the wave maker experiment in NCKU's ship model towing tank to observe the changes and effects on the AUV motion data for different wave heights. By experimenting with simulation, we can be closer to the state of the real ocean environment. The experiment of the AUVs affected by wave maker in NCKU's ship model towing tank is illustrated in **Figure 11**.
