Autonomous Underwater Vehicles for the 2018 RoboSub Competition

The underwater robot team of HEU (Harbin Engineering University) has been built for many years. In recent years, we have attended many robot competitions, and gained many experiences. We improved our robot constantly and hope our robot have a perfect performance. This year, a new robot “Aoming II” was made by”HEU-AUV”, which has been developed in many way. Our team consists of visual group, software group, hardware group, mechanical group, navigation group,sonar group, and this structure makes the team more efficient. I. COMPETITION STRATEGY Firstly, we analysed the problems we met during the past competition with the final run video,several problems were aroused: 1,The shake of image, which was caused by the sway of the robot when the distance between camera and object longer than 3 meters. 2,The glaring sunlight influenced the image and created noise spots in the images. As shown in Figure 1, these noise spots can become the reason of the failure of algorithm. 3,USBL’s signal influenced by running motor. 4,The depth sensor had temperature drift. 5,USBL system was not precise and fast enough to guide the AUV arrive above the acoustic pinger. Figure 1:sunlight spot Beyond these problems, we realized that to score more points, our robot must have ability to finish most of the tasks. But it’s hard to finish the work with the old robot, because the old robot was designed for reaching high speed with a fairshaped design, which means it will be hard to refit the mechanical structure. Therefore, our team decided to design a new robot. We divided the tasks into two categories, one includes the tasks which we had a clear way of achieving so that we don’t have to spend much time on the technology, such as mechanical as the acoustic strategy, the algorithm of vision servo, and the robust detection algorithm. So on the one hand, some of us were concentrating on the basic mechanical frame, PID control algorithm, USBL system and so on, and the rest of us were trying to find an effective method from the paper to solve the challenge problem. We had spent about three months discussing the method of solving these key technical goals: 1,vision servo algorithm for object grasping. 2,small object detection for golf ball . 3,More fast and stable acoustic system . And with these goals reached, we will have chance to finish most of the tasks. Aoming II, our new robot can achieve 6 degrees of motions with eight brushless motors. And it was equipped with a more accurate ultra-short baseline hydrophone than the one on Aoming II which can help the robot achieve acoustic navigation. And it was also equipped with DVL and INS to get robot’s relative location. Besides, it was equipped with efficient and simple grasping system and shooting system. NVIDIA platform Jetson TX2 is employed as core computer, the program runs under the ROS software framework. The front view stereo camera and the stereo camera below robot body to help Autonomous Underwater Vehicles for the 2018 RoboSub Competition “HEU-AUV” Harbin Engineering University 2 of 5 obtain information like the location of the target to complete the visual servo task