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The autonomous displacement and displacement measurement functions of the maglev ruler are performed by the mover core. The magnetic levitation ruler can serve as a viable alternative to the linear measurement system of a coordinate measuring machine. The stability of the four magnetic fields in air gaps and the levitation position of the maglev ruler is one of the key factors for the stability of the thrust force on the power core, and it is also one of the key factors for ensuring the precision of the maglev ruler. There is cross-coupling between the two ends of the mover core of the maglev ruler, resulting in a strongly coupled, nonlinear, multi-input and multi-output system for the levitating system of the maglev ruler. This paper establishes a mathematical model for the levitating system of the maglev ruler and designs a levitating control system for the maglev ruler based on an active disturbance rejection control algorithm to achieve decoupling and disturbance suppression. Through simulation analysis and experimental testing of the levitating system with starting and disturbance, it is proved that the levitating control system of the maglev ruler has good dynamic characteristics, static characteristics, and robustness.

A pillow plate heat exchanger (PPHE) is one of the types of heat exchangers that haven't received the attention they deserve despite their high efficiency and operational capability. A unique feature of PPHEs is their pillow-shaped structure, which is achieved through hydroforming. In light of this, scholars have been interested in analyzing and optimizing the thermo-hydraulic properties of PPHEs. In this study, the interior of the PPHE was occupied with a permeable substance with a high porosity percentage (0.9034 ≤ ɛ ≤ 0.9586 and 0.00015 ≤ dp ≤ 0.00065) and saturated with Ag-water (0 ≤ϕ ≤ 0.06) nanofluid, which has a profound influence on the heat transfer rate of PPHEs. In order to analyze the determinants affecting the heat transfer rate of PPHEs under these conditions, the governing equations were solved using the finite volume method and also the Brinkman-Forchheimer-extended Darcy equation. According to the results, heat transfer is enhanced in PPHE when using a permeable medium with high porosity and a small pore size. That is, PPHEs transfer heat more efficiently when they are placed in a denser porous medium because heat conduction is boosted. Moreover, due to the increased thermal conductivity of the nanoparticles, the application of nanoparticles to the base fluid also enhanced heat transfer and Nusselt number. However, decreases in friction factor and entropy generation were observed with increasing porosity, pore size, and Darcy number, due to reduced flow resistance. A decrease in Richardson number also results in a decrease in friction factor and entropy generation. At the wake region of welding spots, the velocity has reached its lowest values; consequently, this led to a reduction in the heat transfer rate. Nevertheless, within dense porous media, at the lower hydraulic diameter points, the conduction contributes to heat transfer improvement. The porous medium acts as a heat sink and absorbs the heat from the welding spot. This allows the heat to be dissipated away from the welding spot, which reduces the velocity and heat transfer rate. The nanofluid, on the other hand, helps to increase the thermal conductivity of the medium, resulting in more heat being transferred to the surrounding material. Consequently, the results demonstrated that PPHEs' thermal and thermodynamic performance could be significantly improved by using a porous medium saturated with nanofluid.

Abstract To study the numerical relationship between the pull-out force and indentation depth of aviation wire crimp terminal, the crimping process between electrical contacts and stranded conductors and the tensile process of crimping assembly were simulated by the explicit dynamic finite element method. Regarding the variation trend of the tension of the crimping assembly with the tensile displacement during the tensile process and the failure mode, the numerical results and the experimental results showed a high degree of fit, and the relative error of the pull-out force was only 2.6%, which verified the reliability of the established numerical model. This model obtained the pull-out force curve of the crimp terminal that changes with the indentation depth. The authors suggest selecting the interval where the pull-out force is not less than 95% of the peak value, and the depth is less than the corresponding value at the peak value as the best value range of the indentation depth.

The single axis linear displacement measurement system of CMM is composed of grating ruler, servo motor and linear motion mechanism. Although the measuring accuracy of grating ruler is high, the accuracy of servo motor and linear motion mechanism is low. Therefore, the complex structure limits the measurement accuracy of the linear displacement measurement system. This paper introduces a novel linear displacement measurement system named magnetic levitation ruler. According to the working principle of grating ruler and the characteristics of magnetic levitation technology, the magnetic circuit design and structural design of magnetic levitation ruler are completed in this paper. The mover core of the magnetic levitation ruler is in the stable working magnetic field provided by the stator yoke. The horizontal control coil wound on the mover core can obtain more stable ampere force to improve the control accuracy of the mover core displacement. Therefore, the mover core can be moved in step mode, and the length of each step is fixed. Each step is the minimum scale of the magnetic levitation ruler. Therefore, the mover core can implement displacement measurement while moving in a linear motion. This paper analyzes the working principle of levitation, horizontal motion, and displacement measurement of magnetic levitation ruler, and determines the structural materials and parameters of magnetic levitation ruler with the help of finite element analysis software. The simulation results show that the levitation force of the magnetic levitation ruler is proportional to the current passing through the levitation coils, and the thrust of the horizontal control coil is less disturbed by the magnetic field. Compared with the linear displacement measurement system with rotational servo motor or permanent magnet synchronous linear motor as the core, the magnetic levitation ruler has stable magnetic field, strong controllability, high integration, and is easier to achieve high-precision control.

Abstract In this study, the relationship between the tensile strength and the indentation depth was studied by analysing the deformation mechanism of the crimping assembly of the aviation wiring harness end. Tensile strength tests were performed on samples of crimping assemblies with different indentation depths. The results showed that the experimental and theoretical values were in good agreement, verifying the validity of the established mathematical model for tensile strength. Based on this model, a reasonable design range for the indentation depth corresponding to the specific combination of contacts and strands was determined.

A reasonable laser wire stripping process parameter set is a prerequisite for high-quality and high-efficiency wire stripping. For the X-ETFE insulated wire used in aviation, this study explores the method of obtaining the optimal stripping process parameters based on a 405 nm wavelength semiconductor laser. Build energy conversion model, mobile heat source model, and finite element simulation numerical model of the laser stripping insulating layer process. Based on the single-factor analysis method, simulate the effect of laser power, scanning speed, and processing time on the kerf width, heat-affected zone width, and cutting seam depth of the insulating layer. The results show that increasing the laser power to improve the stripping efficiency will also increase the width of the kerf and heat-affected zone, and increasing the scanning speed can effectively reduce the kerf width. A reasonable combination of laser power and scanning speed can improve stripping efficiency while ensuring quality. According to the single-factor simulation analysis results, select the possible value levels for each parameter to carry out the actual laser wire stripping orthogonal test. There is a good correspondence between the range analysis results of the test data of each stripping quality evaluation index and the conclusions obtained from the single-factor simulation, which verifies the reliability of getting the optimal combination of laser stripping process parameters through the orthogonal test.

Free-form surfaces have good aberration correction capability and balance capability for nonrotationally symmetric imaging systems. In this study, we analyzed the quantitative relationship between X–Y polynomial combination and aberration for the efficient design of X–Y free-form optical systems. The purpose of this study was to provide an exhaustive design method for off-axis triple inverse optical systems with X–Y free-form surfaces. Finally, we designed a free-form off-axis optical system with a large field of view (FOV) and low distortion based on the off-axis triple inverse optical system without an intermediate image plane. The primary mirror (PM) of the system adopted an X–Y polynomial free-form surface to correct the aberration of different FOVs of the system and improve the image width and quality. The optical system had a focal length of 1000 mm, an F-value of 9.5, an FOV angle of 23° × 1°, a maximum distortion grid in the FOV less than or equal to −0.05%, and a full-field average wave aberration better than 0.055 λ (λ/18.2, λ = 632.8 nm). The analysis of the design results showed that the system had high-quality imaging and a compact structure. This design method can provide a technical reference for the study of such free-form off-axis systems.

Audio-visual speech recognition (AVSR) utilizes both audio and video modalities for the robust automatic speech recognition. Most deep neural network (DNN) has achieved promising performances in AVSR owing to its generalized and nonlinear mapping ability. However, these DNN models have two main disadvantages: 1) the first disadvantage is that most models alleviate the AVSR problems neglecting the fact that the frames are correlated; and 2) the second disadvantage is the feature learned by the mentioned models is not credible. This is because the joint representation learned by the fusion fails to consider the specific information of categories, and the discriminative information is sparse, while the noise, reverberation, irrelevant image objection, and background are redundancy. Aiming at relieving these disadvantages, we propose the auxiliary loss multimodal GRU (alm-GRU) model including three parts: feature extraction, data augmentation, and fusion & recognition. The feature extraction and data augmentation are a complete effective solution for the processing raw complete video and training, and precondition for later core part: fusion & recognition using alm-GRU equipped with a novel loss which is an end-to-end network combining both fusion and recognition, furthermore considering the modal and temporal information. The experiments show the superiority of our model and necessity of the data augmentation and generative component in the benchmark data sets.

With the continuous development of science and technology, industrial production has higher and higher requirements for precision. Many high-precision measurement technologies emerge as the times require, and nanoscale grating ruler displacement measurement technology is one of them. As a kind of precision sensor, nanoscale grating ruler has important application in displacement measurement system. CPLD has the advantages of high integration and fast programming speed, which is often used to control the displacement measurement system of nanoscale grating ruler. The purpose of this paper is to deeply explore the measurement effect and related application principle of nanoscale grating ruler displacement measurement system based on CPLD technology. A set of nanoscale grating ruler displacement measurement system is designed based on CPLD technology. The output signal of grating ruler is programmed by CPLD. The x-axis displacement of the experimental platform controlled by stepping motor is measured, and the measured data are recorded by carrying out analysis and research. The results show that compared with the traditional phase difference measurement system, the measurement accuracy of the system based on CPLD is improved by 24.7%, the robustness of the measurement system is improved by 18.6%, and the measurement speed is increased by 27.3%. Therefore, this kind of nanoscale measurement precision grating ruler displacement measurement control system based on CPLD has three characteristics: high measurement accuracy, strong anti-interference ability, and high measurement motion efficiency, which can effectively meet the requirements of grating ruler displacement measurement system for high-precision manufacturing technology.

Statement of Retraction: We, the Editor and Publisher of Applied Artificial Intelligence, have retracted the following article: Zhang Maoyun, Xi Huizhuang, Tang Chen, Jiang Yuheng, Zhang Ziyan & Tian Chunlin, Binding Mechanism of Aviation Wire Harness Based on Improved Particle Swarm Optimization, Applied Artificial Intelligence Since publication, concerns have been raised by the authors about the integrity of the data presented in the article. The authors have identified issues with the programming statistics that have led to conclusions which are not credible and have requested the retraction of the article. We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as "Retracted". [ABSTRACT FROM AUTHOR]