In this study, simulations and experiments were conducted on reducing the heave and pitch motions of a catamaran. To serve as stability appendages, an actively controlled T-foil and flap were designed, including their dimensions and installation position on the catamaran. Based on the uncoupled analysis of the appendages, the following control strategies were adopted: the previously proposed resultant force and moment distribution with feedback by displacement (RFMD-D) and the newly developed resultant force and moment distribution with feedback by velocity (RFMD-V). These two control strategies were applied to an S-plane controller, and their performances were tested in simulations and experiments. Finally, a bare catamaran and catamaran with actively controlled appendages were towed in a towing tank, and the two control strategies were tested. The results showed that both control strategies are effective and that RFMD-V is more effective than RFMD-D.
This study investigates the status quo of Teachers' Informationized Teaching Ability in a junior middle school in Shanghai. It adopts the instruments of questionnaires and interviews. Based on the data collected in the research, the results are as followed: (1) Teachers in this school have a positive attitude towards application of information technology into the curriculum and keep up with the tide of educational informationization in China; (2) The concept of being student-centered is emphasized in the use of teaching and learning resources and the rate of redevelopment of online resources increases a lot and timely feedback is highlighted in the information management mode; (3) Teachers' Informationized Teaching Ability to deal with problems in teaching practice and research varies a lot. Faced with the dynamic changes in current educational situation, teaching practice in this school is rewarding. However, there exist some problems which need to be worked out. Therefore, it is suggested that the overall improvements of teachers' Informationized Teaching Ability must combine study of theory on IT-based education with regular training on teaching practice; Secondly, learning community must be established to focus on the curriculum design, the characteristics of e-learning space and the cognitive and emotional features of the students so as to guide the students' autonomous learning more scientifically; Thirdly, action research can be conducted to help teachers reflect on their own teaching experiences in the forms of teaching reflection notes and share with each other and then in turn better their own teaching continuously.
In order to mitigate the excessive amplitudes of pitch and heave motions, a real‐time predictive control method is proposed for the high‐speed multihull with strict input constraints of anti‐pitching appendages. The vertical control model of the high‐speed multihull has been established with T‐foil and flap served as anti‐pitching appendages, and the motion couplings between heave and pitch have been analyzed. The wave disturbance considered as a kind of colored noise can be whitened so as to obtain the control signal, and then adaptive extended Kalman filtering method can be used to get the online estimates of the heave velocity and pitch angular velocity. The proposed predictive control‐based anti‐pitching method mainly contains two reformed aspects of the predictive control. One is to take into account the error between the actual and predicted system values, such that the prediction model with linear error correction can be obtained resulting in the enhanced robustness. The other is to employ the Laguerre function to convert the control sequence of moving horizon optimization into the fewer‐dimensional Laguerre parameters, and then the computational burden of online optimization can be significantly reduced indicating the improved real‐time performance. The closed‐loop system stability has also been theoretically analyzed. The simulation and experiment have been carried out to verify the effectiveness of the proposed algorithm in this paper.
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