Based on the basic theory of harmonic drive, circular spline profile is computed by envelope method when flexspline profile chooses double circular-arc tooth. The load distribution among the teeth of the flexspline has been calculated under different working conditions. When the force intersection angle of the four-acting-force wave Generator decreases, the load distribution will become centralized, and the maximum force acting on the areas of the teeth will also increase.

With the rapid development of Internet of Things (IoT) and Internet technology, the network is becoming more and more important and strict. The IoT networks that access to a large number of devices make network intrusion more convenient. However, because the traditional network intrusion detection methods have the problems of low detection rate and high false alarm rate, this paper proposes a network intrusion detection method based on data mining. Firstly, a pre‐processing model is established to process the initial data. Then, according to the characteristics of network behavior, a new feature subset selection process is designed. Based on the above data mining and analysis process, a dynamic detection generation rule matching with data mining is set to detect abnormal network intrusion traffic. Then, the network intrusion detection based on data mining is completed. The experimental results show that, compared with other methods, the network intrusion detection method based on data mining has higher network intrusion detection rate and lower false alarm rate, which is helpful to improve the detection accuracy.

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In order to realize the high efficiency and precision clamping of large workpieces with several processes and multiple species processing, the distribution number and position of the zero point clamping unit in the flexible quick-change process system for big thin-walled cylindrical structural parts are presented. The error model of the flexible quick-change process system is established by the Monte Carlo method, which is used to optimize the system structure design. The error variation of the flexible quick-change process system under the action of transposition and extreme working conditions such as cutting force is revealed, and further analysis on the sensitivity of the workpiece’s global displacement error and global attitude error to each error source is carried out. After the optimization, a high-quality, cost-effective, flexible quick-change clamping system is created. The three-coordinate measurement experiment is used to test the functionality and accuracy of the flexible quick-change process system. A significantly improved level of the system’s repetitive positioning accuracy (less than 0.01 mm) is detected. Importantly, the flexible quick-change system obtained by the combinatorial optimal design method has been successfully applied to the production of aerospace components with improved quality and efficiency.