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Underwater Vehicles Part 11

Tham khảo tài liệu 'underwater vehicles part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Development of Test-Bed AUV ISiMI and Underwater Experiments on Free Running and ViSion Guided Docking 389 Noise Light Sources from the External Environment -Similar or Brighter than Dock lights -Unpredictable Existence and Motion Inversed Dock Image reflecting from the water surface -Similar Intensity to Dock Lights Fig. 18. Raw Image left and Noisy Luminaries right Several lamps were outside of the basin and the dock lights are reflected down from the water surface. Processed Image - Noisy has been eliminated - Detected lights of the dock are marked by squares - Estimated center of the dock is marked. Fig. 19. Image process sequence test screenshots was used Raw image left binary image-some noisy luminaries remain. center and processed image - elimination of noisy luminaries and discrimination of the dock lights. 7. Final approach algorithm It was first suggested by Deltheil et al 2000 that a vision system is suitable for docking because it offers simplicity stealthiness and robustness. In this chapter a final approach algorithm based on vision-guidance is suggested. It was supposed that the AUV could be 390 Underwater Vehicles guided to the dock by controlling only yaw and pitch. This final approach algorithm generates reference yaw and reference pitch and makes the AUV track them. The docking stage begins when the AUV arrives within 10-15 m in front of the dock. The docking stage of the return process is subdivided here into two stages because there exists an area where the dock lights are out of the camera viewing range when the AUV is close to the dock. Figure 20 shows the first and second stages. During the second stage the AUV is about 1.4m from the dock and the lights of the dock are out of the range of the camera. The essential difference of the second stage is the manner of generating reference yaw for steering motion and reference pitch for diving motion. During both parts of the docking stage a conventional Proportional-Derivative PD control is applied