This paper proposes a calibration method for angular positioning deviation of a high-precision rotary table based on the laser tracer multi-station measurement system. The algorithm error of the calibration method for angular positioning deviation of a high-precision rotary table based on the laser tracer multi-station measurement system was mainly discussed. During the experiments, the laser tracer was fixed on the work surface of the rotary table, and the rotary was fixed on the work surface of the coordinate measurement machine (CMM). The rotary table was rotated with the same angular interval. In this case, an optimization method for calculating the coordinates of a laser tracer station by using Levenberg–Marquardt algorithm and singular value decomposition transform was proposed. Then, the angular positioning deviation of the rotary table was calibrated by an established geometric relationship model between the coordinates of laser tracer stations and the rotation angle of the rotary table. The angular positioning deviation of the high-precision rotary table was as low as ±0.9″, and the error of the calibration method was ±0.4″. The experimental results proved the feasibility of the proposed calibration method. The calibration method proposed in this paper is suitable for the case that the rotary table is not linked with the CMM, especially for large high-precision rotary tables.

Jamming style denial-of-service attack is the transmission of radio signals that disrupt communications by decreasing the signal to noise ratio.This kind of attack can be easily launched by jammer through either bypassing MAC-layer protocols or emitting a radio signal targeted at blocking a particular channel. In this paper, we consider the item of localizing a jammer in which little work has been done. First we explored the existing localization algorithms that have been used in wireless sensor networks. We then proposed a geometry-covering based localization (GCL) algorithm, which utilizes the knowledge of computing geometry, especially the convex hull. Simulation results showed that GCL is able to achieve higher accuracy than centroid localization, and has the time complexity of O(n logn), which is proper to sensor networks.

With the continuous improvement of the theory and method of gear measurement, the effectiveness of gear contact measurement is reduced, making it difficult to meet the need for 100% gear detection. To improve the measurement efficiency and make effective use of the full tooth surface data, a gear pitch rapid measurement method by point laser sensor is proposed. This method studies the principle of measuring the gear based on a laser point sensor, and the efficient model of collection and analysis of tooth surface data is established. Then the evaluation of the pitch deviation is completed, including the individual single pitch deviation, the single pitch deviation, the individual cumulative pitch deviation, and the total cumulative pitch deviation. Additionally, the pitch deviation of the multiple cross-sections is investigated, which may characterize the overall pitch deviation of the tooth surface. Compared to the gear measuring center P26, the experimental results show that the optical measurement of pitch deviation is feasible and efficient. Depending on the different measuring conditions, the offset status of the sensor can be selected to meet the different efficiency and accuracy requirements. The research and application potential of a point laser sensor in gear measurement is wide-ranging.