Bearing mechanism of roof and rib support structure in automatically formed roadway and its support design method

Non-pillar mining technology with automatically formed roadway is a new mining method without coal pillar reservation and roadway excavation.The stability control of automatically formed roadway is the key to the successful application of the new method.In order to realize the stability control of the roadway surrounding rock,the mechanical model of the roof and rib support structure is established,and the influence mechanism of the automatically formed roadway parameters on the compound force is revealed.On this basis,the roof and rib support structure technology of confined lightweight concrete is proposed,and its mechanical tests under different eccentricity are carried out.The results show that the bearing capacity of confined lightweight concrete specimens is basically the same as that of ordinary confined concrete specimens.The bearing capacity of confined lightweight concrete specimens under different eccentricities is 1.95 times higher than those of U-shaped steel specimens.By comparing the test results with the theoretical calculated results of the confined concrete,the calculation method of the bearing capacity for the confined lightweight concrete structure is selected.The design method of confined lightweight concrete support structure is established,and is successfully applied in the extra-large mine,Ningtiaota Coal Mine,China.

Towards fast focal mechanism inversion of shallow crustal earthquakes in the Chinese mainland

We have developed an automatic regional focal mechanism inversion system based on the Earthquake Rapid Report(ERR) system and the real-time three-component seismic waveform stream of 1 000 broadband seismic stations provided by the China Earthquake Networks Center(CENC). The system can rapidly provide a double couple solution and centroid depth within 5–15 min after receiving earthquake information from the ERR system.The data processing is triggered by earthquake information obtained from the ERR system. The system is capable of determining the focal mechanism of all shallow-depth earthquakes in the Chinese mainland with a magnitude of 5.5–6.5. It utilizes waveform data recorded by seismic stations located within 500 km from the epicenter,enabling the reporting of a focal mechanism solution within 5–15 min of an earthquake occurrence. Additionally,the system can assign a corresponding grade(A B C) to the focal mechanism solution. We processed a total of 301earthquakes that occurred from 2021 to June 2022, and after the quality control, 166 of them were selected.These selected solutions were manually checked, and 160 of them were compiled in a focal mechanism catalog.This catalog can be conveniently downloaded online via the Internet. The automatic focal mechanism solution of earthquakes in eastern China exhibits a good agreement with that provided by the Global Centroid Moment Tensor(GCMT), when available. The average Kagan angle between this catalog and GCMT is 22°, and the average difference in MWis 0.17. Furthermore, compared with GCMT, the minimum magnitude of our catalog has been reduced from approximately 5.0 to 4.0. The correlation between the centroid depth and crustal thickness in the Chinese mainland confirms the distribution of the centroid depth.

Mathematical modeling and analytical solution for stretching force of automatic feed mechanism

Load of an automatic feed mechanism is composed of the stretching force of feed belt at the entrance to lower flexible guidance and the friction force between feed belt and flexible guidance. A mathematical model for computing the load was presented. An optimization problem was formulated to determine the attitude of the flexible guidance based on the principle that the potential energy stored in the system was the minimum at the equilibrium. Then the friction force was obtained according to the attitude of guide leaves and the moving velocity of the feed belt and the friction factor. Consequently, the load of the automatic feed mechanism can be calculated. Finally, an example was given to compute the load when the horizontal and elevating firing angles of the automation were respectively 45° and 30°. The computing result can be a criterion to determine the designing parameters of automat.

Research on Cam-linkage Mechanism of Automatic Piecing Device

The principle of an automatic piecing device is presented, and the mathematic model of a specific combined mechanism of the automatic piecing device is analysed. The kinematics and dynamics equation of the combined mechanism is established on the basis of the mathematic model. By the virtual prototype technology, the motion of this mechanism is simulated, whose result is post-processed by ADAMS. To improve the output motion, according to the simulation output and automatic piecing device's practical working condition, the optimisation of the cam mechanism is carried out by finite difference method. The simulation result of this combined mechanism turns out in accordance with its theoretical analysis of virtual prototype in this research, which, therefore, lays a principle basis for the further study of automatic piecing device.

A Method for Automatically Establishing a Mathematical Model of Kinematic Analysis to a Planar Mechanism with a Multiple Joint and Prismatic Pair

A method for automatically establishing a mathematical model of kinematic analysis to a planar mechanism with multiple joint and prismatic pair is presented. The breadth （ or depth ） first search spanning tree can be obtained based on an adjacency matrix of the mechanism. Then the kinematic chain （or mechanism）＇s basic loops can be obtained. On the basis of these basic loops, a mathematical model of kinematic analysis can be established and solved automatically. In the sense of a calculative mechanism, structural analysis of the kinematic chain relates to the kinematic analysis of a mechanism. Thus, an effective way is supplied to the given mechanism＇s kinematic analysis for automatic modeling and solving, and a method is supplied to the structural type to optimize kinematic synthesis.

Adaptive Clutch Engaging Process Control for Automatic Mechanical Transmission

Based on detail analysis of clutch engaging process control targets and adaptive demands, a control strategy which is based on speed signal, different from that of based on main clutch displacement signal, is put forward. It considers both jerk and slipping work which are the most commonly used quality evaluating indexes of vehicle starting phase. The adaptive control system and its reference model are discussed profoundly. Taking the adaptability to different starting gears and different road conditions as examples, some proving field test records are shown to illustrate the main clutch adaptive control strategy at starting phase. Proving field test gives acceptable results.

OPTIMAL TORQUE CONTROL STRATEGY FOR PARALLEL HYBRID ELECTRIC VEHICLE WITH AUTOMATIC MECHANICAL TRANSMISSION

In parallel hybrid electrical vehicle （PHEV） equipped with automatic mechanical transmission （AMT）, the driving smoothness and the clutch abrasion are the primary considerations for powertrain control during gearshift and clutch operation. To improve these performance indexes of PHEV, a coordinated control system is proposed through the analyzing of HEV powertrain dynamic characteristics. Using the method of minimum principle, the input torque of transmission is optimized to improve the driving smoothness of vehicle. Using the methods of fuzzy logic and fuzzy-PID, the engaging speed of clutch and the throttle opening of engine are manipulated to ensure the smoothness of clutch engagement and reduce the abrasion of clutch friction plates. The motor provides the difference between the required input torque of transmission and the torque transmitted through clutch plates. Results of simulation and experiments show that the proposed control strategy performs better than the contrastive control system, the smoothness of driving and the abrasion of clutch can be improved simultaneously.

Defect Analysis and Innovation Design of Synchronizer for Clutchless Automatic Mechanical Transmission

The synchronizer is a key component of automatic mechanical transmission(AMT)equipped in electric vehicles,but the inertial lock-ring synchronizer(ILRS)commonly used there is not suitable especially for pure electric vehicles without a clutch because of big shift impact.To make the shifting process rapid and smooth,a new synchronizer named pressure-controllable friction ring synchronizer(PCFRS)was designed.Initially,the inevitable shortcoming of ILRS was verified by simulation and test.Furthermore,the mechanical characteristics and advantages of the new synchronizer over ILRS were analyzed.Then,the formulations describing the dynamic transmission based on the working mechanism of the PCFRS were established.Finally,the shifting simulation results with PCFRS and ILRS based on the same operating conditions were compared and analyzed.The research shows that the PCFRS can meet the main shifting evaluation index of an AMT without complex control methods,as well as it takes only 0.2406 s to finish the comfortable and zero-speed-difference shifting.The shifting quality of PCFRS is better than that of the ILRS.It lays a foundation for using the new synchronizer as a part of clutchless AMTs equipped in pure electric vehicles.

The Application of Automatic Welding in Mechanical Welding

With the development of science and technology, automation technology has begun to be applied to various fields. Automatic welding technology is increasingly used in the welding industry in the area. The introduction of automatic welding technology not only improve the quality and production efficiency, but also reduce production costs, the production environment in which the staff has also been improved. This paper discusses the current situation of automatic welding technology, mechanical industry, the demand for automatic welding, automatic welding technology advantages and development trends.

Design and application of electric oil pump in automatic transmission for efficiency improvement and start–stop function

For the purpose of improving efficiency and realizing start–stop function, an electric oil pump(EOP) is integrated into an 8-speed automatic transmission(AT). A mathematical model is built to calculate the transmission power loss and the hydraulic system leakage. Based on this model, a flow-based control strategy is developed for EOP to satisfy the system flow requirement. This control strategy is verified through the forward driving simulation. The results indicate that there is a best combination for the size of mechanical oil pump(MOP) and EOP in terms of minimum energy consumption. In order to get a quick and smooth starting process, control strategies of the EOP and the on-coming clutch are proposed. The test environment on a prototype vehicle is built to verify the feasibility of the integrated EOP and its control strategies. The results show that the selected EOP can satisfy the flow requirement and a quick and smooth starting performance is achieved in the start–stop function. This research has a high value for the forward design of EOP in automatic transmissions with respect to efficiency improvement and start–stop function.

Variable-mass Thermodynamics Calculation Model for Gas-operated Automatic Weapon

Aiming at the fact that the energy and mass exchange phenomena exist between barrel and gas-operated device of the automatic weapon, for describing its interior ballistics and dynamic characteristics of the gas-operated device accurately, a new variable-mass thermodynamics model is built. It is used to calculate the automatic mechanism velocity of a certain automatic weapon, the calculation results coincide with the experimental results better, and thus the model is validated. The influences of structure parameters on gas-operated device's dynamic characteristics are discussed. It shows that the model is valuable for design and accurate performance prediction of gas-operated automatic weapon.

Optimal Guaranteed Cost Control Algorithm for Automatic Chain Shell Magazine

The automatic chain shell magazine is the primary subassembly of the automatic ammunition loading system of a big-caliber howitzer. Due to the change of the shell amount in the magazine during firing, its positioning control is a kind of control problem of systems with uncertain parameters. In order to realize accurate control of shell position, an optimal guaranteed cost control algorithm based on linear matrix inequality (LMI) theory was put forward. The motion equations of the magazine were built, and the motion equations for four special load situations were linearized; according to the basic theory of the guaranteed cost control, the motion equations were written as the standard forms for linear uncertain systems; the optimal guaranteed cost control law for the position control of the magazine was obtained by use of LMI toolbox in MATLAB package. Using this control law, the controlled dynamic simulation of the shell magazine was carried out. The simulation results indicate that the control algorithm has high control precision.

Dynamics analysis on transverse cutting mechanism of straw checkerboard paving robot

The transverse cutting mechanism of the checkerboard paving robot, which directly affects the robot＇s operation, is regarded as the most important part in a transverse pavement system This research aims at designing a new system which is appropriate for desert wofidng en- vironments and finishing cutting the rope of straw. In this paper, computer emulating technology is applied, and with three-dimensional modeling by Pro/ENGINEER software, can observe whether or not interference exists. Also, the speed and displacement parameters of the main parts of the cutting system are given by the dynamic emulation by Automatic Dynamic Analysis of Mechanical System （ADAMS）, which theoretically assures the feasibility and appropriateness of the cutting mechanisrn~ Finally, results of the experinaent shows that the cutting mechanism can cut the straw strand as designed.

Real-Time, Automatic and Wireless Bridge Monitoring System Based on MEMS Technology

Currently, the monitoring of bridges in China heavily relies on manual operation, which has several major problems. It generally takes a very long time to complete an inspection process on bridges. The manual data is sometimes unreliable or even wrong in the case of careless operation. The inspection activity itself is dangerous for inspectors, e.g., bridges are located in the sea or river. Some semi-automatic monitoring methods are recently employed, but they are either very expensive or do not work properly. Therefore, the traditional bridge monitoring process becomes an increasing challenge for bridge operators. In this paper, a real-time and automatic bridge monitoring system is presented to meet the bridge monitoring needs, and MEMS （Micro Electro Mechanical Systems） are the key building block in this system. By using the MEMS-based sensors, it is much more efficient and accurate in monitoring bridges with the measurement of inclination, acceleration, displacement, moisture, temperature, stress and other data.

内牙水管接头的注塑模具设计及CAE仿真

针对一端带有内螺纹和另一端为光孔的水管接头,设计了一套带有齿轮传动+抽芯液压缸的自动脱螺纹机构和斜导柱侧抽芯机构的三板式注塑模具。首先,结合塑件的结构特点,确定了点浇口进胶以及浇口位置和直流循环式的冷却回路,利用模流仿真分析软件moldflow对确定的模流分析模型进行注塑成型工艺过程模拟分析。结果表明,塑料熔体的充填时间、缩痕指数、气穴分布以及翘曲变形量等成型工艺参数都在合理范围之内,验证了浇注系统和冷却系统设计的合理性。其次,对模具结构进行设计,将主分型面取在塑件的轴心面上,其余两个分型面顺序分型实现浇注系统凝料的自动脱落。由于塑件为带内螺纹的管状零件,针对内螺纹脱模难的问题,设计了齿轮传动机构驱动螺纹侧型芯旋转和抽芯液压缸的直线移动的两套运动机构实施自动脱螺纹,塑件光孔部分的成型和抽芯采用斜导柱侧抽芯机构来实现。通过模流分析,验证了模具结构的合理性,并且缩短了模具设计的开发周期,有效地提高了塑件的成型质量。

PLC技术的造纸机械设备自动控制系统设计与研究

新型造纸公司依托于高科技实现了生产流程的机械化和自动化,造纸行业的生产效率和效益都得到了提升。PLC技术在工业自动化生产中应用广泛,在造纸机械设备的应用有利于提高造纸设备的自动化运转,同时有助于提高产品的质量,节约产品的人力成本和时间成本等。对PLC技术进行了简要介绍,并讨论了其在造纸机械设备的应用的形式以及自动化设计系统的设计等,为造纸行业的进一步发展提供更多的技术支撑。

机械通气人机不同步自动检测算法综述

该研究总结了患者与呼吸机非同步性(patient-ventilator asynchrony,PVA)自动识别技术在机械通气过程中的应用。在早期阶段,规则及阈值的设定方法依赖于呼吸机参数及波形的人为解析,虽然这类方法直观并易于操作,但在阈值设定和规则选择上相对敏感,不能很好地适应患者状态的微小变动。随后,机器学习和深度学习的技术开始出现并发展。这些技术通过算法自动提炼和学习数据特性,使PVA的检测更具鲁棒性和通用性。其中,逻辑回归、支持向量机、随机森林、隐马尔可夫模型、卷积自编码器、长短期记忆网络、一维卷积神经网络等方法都被成功地用于PVA的识别。尽管深度学习方法在特性提取上取得了显著进步,但是它们对标签数据的需求较大,可能会消耗大量医疗资源。因此,强化学习与自监督学习的结合可能是一个实际可行的解决方案。此外,算法的验证大多基于单一的数据集,未来对于跨数据集验证的需求将是一个重要且充满挑战性的发展方向。

数字孪生下的液压缸机械运行位置自动控制

液压缸机械系统非线性特征复杂,机械运行行为特征不明确,位置控制结果存在偏差,对此,该文提出数字孪生下的液压缸机械运行位置自动控制方法。连续检测液压缸机械系统运行状态,构建非线性状态方程,对比实际测量数据与输出数据的差异,选取RBF核函数与支持向量机,机械运行位置变化量,描述机械运行行为特征,建立位置控制目标函数,将最高适应度值对应的位置点自动更新为副本位置点,引入猫群算法求解目标函数,对位置控制目标函数的全局最优解展开更新,实现液压缸机械运行位置自动控制。实验结果表明,所提方法应用后,位移检测曲线与实际位移曲线之间的偏差较小,且在恒负载工况下和变负载工况下,位移稳态误差均较小,说明其机械运行位置自动控制结果精度高、控制效率高、控制精度高。

基于可微分架构搜索的多载波信号自动调制识别

针对城市多径信道下缺乏多载波信号通用数据集,以及传统信号特征与网络模型难以有效识别低信噪比下失真信号调制类型的问题,提出一种基于可微分架构搜索的多载波信号自动调制识别算法。首先,产生了常见OFDM、FBMC与OTFS多载波信号经过典型城市多径信道的接收信号数据集,选取对调制参数不敏感的信号时频图作为特征向量来训练神经网络;其次,采用可微分架构搜索方法自动搜索最佳网络结构,避免了网络结构设计的反复验证工作;最后,在特征学习过程中引入联合注意力机制,将失真信号特征进行空间转换以降低多径干扰影响,同时计算特征图各通道信息权重并排序,以提升相关特征图通道的分类效果。仿真结果表明,所提算法不仅能提升在城市多径信道环境下尤其是低信噪比时的识别正确率,而且对调制参数变化和小样本场景具有更好的鲁棒性。

基于自注意力机制神经机器翻译的软件缺陷自动修复方法

循环神经网络对于代码序列数据有着良好的处理能力,软件缺陷修复的补丁生成模型大多采用循环神经网络实现.然而,基于循环神经网络的补丁生成模型在处理代码序列中长距离依赖问题时仍然具有局限性,其修复成功率和修复效率较低.针对此问题,提出一种基于自注意力神经机器翻译的软件缺陷自动修复方法(Self-attention Neural machine translation based automatic software Repair,SNRepair).首先,为有效缓解源码中的未登录词问题,对数据集引入子词切分技术进行预处理;其次,为解决源代码中棘手的长距离依赖问题并更充分地利用局部信息,构建融合局部建模的Transformer程序补丁生成模型;然后,采用缺陷自动定位技术定位缺陷语句位置,利用参数优化后的Transformer补丁生成模型生成候选补丁;最后,运行测试用例验证候选补丁.在具有395个真实Java软件缺陷的Defects4J缺陷库上实验评估,结果表明SNRepair方法与对比方法比较,修复成功率和修复效率更高.