The magnetohydrodynamic (MHD) angular rate sensor (ARS) with low noise level in ultra-wide bandwidth is developed in lasing and imaging applications, especially the line-of-sight (LOS) system. A modified MHD ARS combined with the Coriolis effect was studied in this paper to expand the sensor’s bandwidth at low frequency (<1 Hz), which is essential for precision LOS pointing and wide-bandwidth LOS jitter suppression. The model and the simulation method were constructed and a comprehensive solving method based on the magnetic and electric interaction methods was proposed. The numerical results on the Coriolis effect and the frequency response of the modified MHD ARS were detailed. In addition, according to the experimental results of the designed sensor consistent with the simulation results, an error analysis of model errors was discussed. Our study provides an error analysis method of MHD ARS combined with the Coriolis effect and offers a framework for future studies to minimize the error.

To realize a one-sided stitching action and stable stitch formation, a poor match between the lead and the hook yarn needles in the stitching process must be avoided as it can lead to hook dropping and hook errors, causing loop loss, thread breaking, and even thread relaxing. Based on an analysis of the principle of one-sided stitching and matching the hook and lead yarn needles, the original stitching technology is improved and a method of trajectory superposition is proposed. A yarn-pulling mechanism is designed for a one-sided stitching device for three-dimensional preformed carbon/carbon composites. By analyzing the principle of the yarn-pulling mechanism, a mathematical model of that mechanism is established, and a trajectory simulation analysis is carried out with MATLAB, which verifies the rationality of the yarn-pulling principle. Results for the two crank angles of the yarn-pulling mechanism and the crank angle of the hook yarn needle at two particular moments reflect the matching relationship of the three, which provides a theoretical reference for the stitching device to adjust to and work well, forming the desired stitch. Finally, stitching tests are carried out, and the test results show the designed yarn-pulling mechanism can cooperate with the hook and the lead yarn needles to complete the stitch lock. This realizes a stable stitching action and avoids hook dropping and hook errors, thereby increasing stitching efficiency.

In this article, the finite-time output feedback sliding mode control problem is investigated for a class of continuous-time linear systems with unmeasurable states. First, a novel terminal sliding mode observer is established to estimate the unmeasured system states. Second, a novel integral sliding surface is introduced with tunable parameters. Then, an output feedback sliding mode controller with power terms is constructed to drive the given system to the origin in a finite time. A switching from the terminal sliding mode to a usual sliding manifold is taken to avoid singularity problem. Finally, two application-oriented examples are offered to verify the effectiveness of the proposed algorithm.

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Recent research has shown that, during integrated piercing, the yarn tension can displace the needles from the centers of the holes in the piercing template. To reduce the damage done to the needle tips when the needles and the hole walls collide when the needle displacement is too large, this paper proposes a method for optimizing the needle shape that satisfies the strength constraint while targeting minimum needle displacement. First, the optimal objective function and strength constraint conditions for the tip displacement of the integrated puncture needle are established, which are affected by many factors. Then, the feature selection method of machine learning is used to reduce the dimensionality of the objective function after data reduction, and the feasible region of key features is reduced to avoid falling into the local best point in the optimization iteration. Finally, machine vision is used to measure experimentally the tip displacement of a needle array. The results show that the average tip displacement is reduced by 18.16–31.42% and the collision risk is reduced from 43.14% to 5.54%. It shows that the optimization method of needle shape based on feature selection is effective for reducing needle tip impact damage during integrated piercing.