| Our country's coastal areas is often subject to different wave's attacks by Typhoon.Study shows that: each year typhoon waves destroyed the coastal protection works and offshore aquaculture industry hazards and the economic loss is more than 700 million yuan. Breakwater is an important form of the protective equipments commonly used in waterfront. As the construction and production developed in our country, the breakwater is more and more important, depth water, far offshore, soft foundation, that's the environment of the new breakwater.In the Tianjin Port breakwater project, Tianjin University and other units designed a new type of box tube breakwater, and in 2005 identified through the Tianjin Science and Technology Commission, reaching the world advanced level. Beginning in 2006,the box tube type breakwater used in the construction of the Tianjin Port in large-scale, also that's the first time the new type of breakwater used in a real project in large-scale. So the relevant departments obtained a tentative plan about the running status of the new type of box tube breakwater and the surrounding environmental parameters changed to the safety performance of the breakwater.But this new type of model can not be designed from the existing norms and needed to simulate the loading environment, in order to reflect the real situation in the waves. As the size of breakwater is very large, Nanjing Institute of Science and Technology proposed the method of centrifuge model test. Overweight conditions in the centrifuge, the traditional way of loading, such as hydraulic loading, electrical cam loading can not meet the requirements of test, so we commissioned by Nanjing Institute of Science and Technology to design the non-contact electromagnetic wave simulation of the dynamic loading system.Electromagnetic force is not subject to the effects of gravity, it's one of four nature force. The experiments show that in the overweight condition the dynamic loading can meet the requirements. From the basic principles of electromagnetism, we know that the electromagnetic force is non-linear, and to load on the breakwater in mud of high damping, high plasticity is very difficult. As the system is nonlinear and time-varying, the traditional PID control technology, while having the algorithm of simple, no steady-state error, etc, can not achieve a smooth and accurate control status. Experiments shows the phenomenon of oscillations and overshoot. In view of this situation, based on the incremental PID control algorithm, used the intelligent control of fuzzy control theory, we designed a fuzzy nonlinear gain controller, the new control method based on traditional incremental PID control and fuzzy gain technology, it has not only the ordinary PID algorithm such as simple and reliable, easy to implement, technology, but also the characteristics of fuzzy control, better robustness and fast convergence, easy to compute.This new control technology is different from the fuzzy PID control technology. Fuzzy PID control technology is based on the change of deviation, In the entire process, PID control parameters should be calculated for each cycle in order to adjust to the non-linear time-varying system. In this paper, proposed the fuzzy non-linear gain of PID control method, the PID parameters, once be identified, the entire process parameters is no need to modify, the algorithm of fuzzy gain control is to strengthen or weaken the PID value of the output. The control method also points with the separation of points, and the "sleep zone". The "sleep zone" is similar to the"dead zone"control technology. System with this control method can be convergence smoothly and fastly when there is a large deviation,or strong interference and step-control. The "sleep zone" control proposed in this paper is a new concept, it can increase control accuracy in the steady-state automatically.Experiments proved that, PID fuzzy non-linear gain control method, can show different control characteristics in different stages. So the non-linear, time-varying systems can achieve real-time control, fast convergence, micro-or-no overshoot, better robustness. The steady-state error is less than 2% when the system is in full-scale, the system meet the design and use requirements absolutely. |
