Lei Hong

The kurtosis of stress response significantly affects the fatigue failure time of structures under nonstationary excitation, making it a vital parameter for characterizing the study of fatigue damage caused by nonstationary vibrations. However, the existing methods have not yet considered the assessment of response kurtosis when the structural modal damping is low, which poses a hindrance to the advancement of vibration fatigue acceleration theories. This study focuses on analyzing the envelope characteristics of the response of linear structures under nonstationary excitation produced by the amplitude modulation method. A novel approach is proposed to assess kurtosis by leveraging the envelope curve of the nonstationary signal response. The simulation results demonstrate that the frequency resolution of signal sampling also impacts the response’s kurtosis. The proposed method offers an accurate evaluation and rapid control of response kurtosis in both numerical and experimental examples.

In this paper, the radar servo system is modeled based on PSO Algorithm and Akaike Information Criterion and system identification theory. It is modeled by linear dynamic equations. Linear model of parameters which have a variety of different orders are identified based on PSO Algorithm whose order can be decided by Akaike Information Criterion. At last, the linear mathematical model of radar servo system can be concluded. The test and the simulation results show that it has great effect that radar servo system is described by this model.

Through taking the cold rolling process as the research object, the three-dimensional finite element model of the strip rolling process is established by using ANSYS/LS-DYNA software. The actual rolling product data has strong consistency with the finite element simulation results. The rolling process is dynamically simulated, and the distribution curves of important rolling parameters such as equivalent stress, control efficiency coefficient, transverse rolling pressure, lateral thickness and work roll deflection is obtained. Based on summarizing the influence of rolling parameters on rolling deformation, the research results of this paper can play an important role in the actual rolling process control. The research results have certain guiding significance for the development and optimization of the rolling control system.

During the flatness control process, there are frequently some uncoordinated regulating behaviors in the flatness actuator group. This has a bad influence on the flatness control accuracy and the flatness control efficiency. Therefore, a collaboration strategy based on conflict resolution for the flatness actuator group has been proposed in this paper. First of all, the feature of flatness measurement value is extracted through establishing the actual flatness condition discriminating factor. After that, the coordination cooperation that is appropriate to the actual flatness condition is developed for the flatness actuator group. Finally, the optimal adjustment of the actuator population is solved by the coordinated algorithm of Topkis-Veinott and genetic algorithm collaborative optimization. The collaboration strategy proposed in this paper has been successfully applied to a flatness control system of a 1450 mm five-stand cold rolling mill.

It is proposed to introduce a novel division based self- motion scheme for redundant joint manipulators to avoid obstacles in a static and known environment. The proposed scheme chooses an intuitionistic manifold of self-motion throughout the workspace. A review of the traditional research on self-motion manifolds for redundant manipulators is presented in this paper. And after an overview of the proposed approach, a comparison between the traditional techniques and this algorithm is made. A 9-DoF modular manipulator illustrates the methodology. Also, an experiment is carried out to verify the effectiveness of this scheme. Although discussed and illustrated mainly by a three degrees of redundancy, it is possible to extend this algorithm to lower or even higher degrees of redundancy.