EFFICIENCY ANALYSIS OF DOUBLE CRANK RING-PLATE-TYPE PIN-CYCLOIDAL GEAR PLANETARY DRIVE

From the general formula for calculating the efficiency of planetary geartrains, the efficiency of the double crank ring-plate-type pin-cycloidal gear planetary drive isderived. To prove the theory, an experimental study has been conducted. The tested value of theefficiency of a sample set of the new-type drive in the experiment agrees with the calculated one.It shows that the new-type drive is of not merely high bearing capacity, but also quite highefficiency.

Double Position Servo Synchronous Drive System Based on Cross-Coupling Integrated Feedforward Control for Broacher

Synchronization errors directly deteriorate the machining accuracy of metal parts and the existed method cannot keep high synchronization precision because of external disturbances. A new double position servo synchronous driving scheme based on semi-closed-loop cross- coupling integrated feedforward control is proposed. The scheme comprises a position error cross-coupling feedfor-ward control and a load torque identification with feed- forward control. A digital integrated simulation system for the dual servo synchronous drive system is established. Using a 20 t servo broacher, performance analysis of the scheme is conducted based on this simulation system and the simulation results show that systems with traditional parallel or single control have problems when the work- table works with an unbalanced load. However, the system with proposed scheme shows good synchronous perfor- mance and positional accuracy. Broaching tests are performed and the experimental results show that the maximum dual axis synchronization error of the system is only 8μm during acceleration and deceleration processes and the error between the actual running position and the given position is almost zero. A double position servo synchronous driving scheme is presented based on crosscoupled integrated feedforward compensation control, which can improve the synchronization precision.

Simulation on model predictive control for PMSM drive system based on double extended state observer

A novel double extended state observer(DESO)based on model predictive torque control(MPTC)strategy is developed for three-phase permanent magnet synchronous motor(PMSM)drive system without current sensor.In general,to achieve high-precision control,two-phase current sensors are necessary for successful implementation of MPTC.For this purpose,two ESOs are used to estimate q-axis current and stator resistance respectively,and then based on this,d-axis current is estimated.Moreover,to reduce torque and flux ripple and to improve the performance of the torque and speed,MPTC strategy is designed.The simulation results validate the feasibility and effectiveness of the proposed scheme.

LOAD DISTRIBUTION ON DRUMS OF DOUBLE DRIVE BELT CONVEYOR

The double drum drive is widely used on the mine belt conveyor, which are divided the rigid connected double drums and separately driving double drums according to connected method of two drums. Because of the change of real work condition, the load distribution is changed on the two drive drums, which may produce a slippage between a drum and belt. Slippage may intensify the wear of the drum, and sometimes causing the fire of the belt. This restricts the development toward narrow belt, high velocity and large power of belt conveyor. In this paper, the factors affecting the load distribution of two drums of double drum belt conveyor are systematically analyzed and some computing formulas derived, by these formulas, the actual lcad distribution on the two drums of rigid connected or separately driving belt conveyor can be separately calculated.These formulas also can be as the theory base for adjusting the driving force of two drums.

Research on Angular Output Velocity of a Drive Shaft with Double Cross Universal Joints

The study object is the angular output velocity of the drive shaft which is made up of two series-wound cross universal joints. We have deduced the function relation between the angular output velocity and initiative input angle of the drive shaft with double cross universal joints that is based on the calculation formula of the angular output velocity of a single cross universal joint, and by analyzing the relation between the two input angles. By using this function relation, the constant velocity condition of the drive shaft with double cross universal joints＂ is verified. The step-by-step searching algorithm is adopted to obtain the optimal phase angle that leads to the minimum fluctuate index of the angular output velocity in the vary velocity condition. At the same time, we worked out the maximal and minimum value of the angular output velocity, and their initiative input angle. The correctness of the function of the angular output velocity and the step-by-step search algorithm are verified by an ADAMS simulation example.

Phase-dependent double optomechanically induced transparency in a hybrid optomechanical cavity system with coherently mechanical driving

We propose a scheme that can generate tunable double optomechanically induced transparency in a hybrid optomechanical cavity system.In this system, the mechanical resonator of the optomechanical cavity is coupled with an additional mechanical resonator and the additional mechanical resonator can be driven by a weak external coherently mechanical driving field.We show that both the intensity and the phase of the external mechanical driving field can control the propagation of the probe field, including changing the transmission spectrum from double windows to a single-window.Our study also provides an effective way to generate intensity-controllable, narrow-bandwidth transmission spectra, with the probe field modulated from excessive opacity to remarkable amplification.

Torque analysis for double-stator permanent-magnet motor

In addition to the characteristics of a conventional motor, a novel direct-drive double-stator permanent-magnet brushless motor proposed can operate in the state of either a generator or a motor as appropriate. Through numerical calculation and analysis, the output torque of double-stator permanent-magnet brushless motor of the same volume as the traditional machine is discussed, and the reduction of torque ripple by using the structure features of this motor is investigated. The results indicate that lower torque ripple under the condition of ideal effective torque can be obtained by the rational design of motor. The prototype motors tested show that this kind of motor structure has a higher power density.

基于车桥耦合振动的双层钢桁梁斜拉桥行车舒适度分析

探究车辆在双层钢桁梁斜拉桥的行车舒适性,为优化双层桥梁结构设计理论提供依据。以车桥耦合振动理论为基础,利用ANSYS分析软件进行数值模拟,通过求解车体的振动加速度,并根据《机械振动和冲击—评估人体暴露于全身振动的情况》(ISO2631-1)中均方根乘值法对乘车舒适性进行评价,探究了单(双)层加载、车速、车载质量、桥面不平顺度、车辆间距、车辆数目等因素对行车舒适性的影响。相较于单层通车,上下层同时通车时车体的振动强度略微降低;当车载质量越小或车速越大时,车体的加速度均方根值会逐渐增大;路面对车体振动强度影响较大,当路面等级处于较差的D级和E级时,车体振动强度会成倍增加。双层同时加载时,车辆的行车舒适性略优于单层通车;保持适当的车速或增大车载质量可以提高司乘人员的行车舒适性;行车舒适性对于路面等级较为敏感,当路面等级较差时,车内司乘人员受其影响无法长时间乘车。

双联液压元件新型应用与性能分析

针对现有传统液压回路在多种不同压力、不同流量工况中需要借助繁多功能控制阀来调节的功能缺陷,以及能耗大、效率低等问题,将双联液压元件应用于几种典型回路中,并对由双联液压元件组成的新型液压系统的节能特性、输出特性进行了研究分析。结果表明:双联液压元件的应用能够节省成本、简化系统、消除压力互相干扰、减少功率损失,实现了功率的匹配,达到了节能目的。

Mathematical modeling and characteristics analysis for the nutation gear drive based on error parameters

We focused on the mathematical modeling and characteristics analysis for the nutation drive based on error parameters. The crown gear tooth profile equation was introduced according to the national standard double circular arc tooth profile and based on the equal tooth strength principle. The nutation drive meshing coordinate system was set up by introducing the cone vertex error, tilt error, nutation angle error and spiral angle error. The tooth profile equations of the double circular arc external and internal spiral bevel gears were further obtained based on the crown gear tooth profile equation concerning above mentioned error parameters. The influences of the nutation gear reducer tooth contact conditions were analyzed with the gear tilt error and axial misalignment error. Finally, the correctness of the theoretical analysis was verified by the contact spot test.

双碳背景下中国制浆造纸产业碳效率时空分布特征研究

我国的制浆造纸产业不仅是国民经济的重要支柱,还面临着能源消耗大、污染物排放量高的挑战。在这样的背景下,深入了解并分析该产业的碳排放情况,对推动行业的绿色转型和实现碳减排目标具有不可小觑的作用。首先,通过探讨造纸行业碳效率的计算方法,综合考察了2002年至2014年我国及各主要省份造纸及纸制品行业的碳排放总体情况及其强度变化,揭示了行业碳排放的地域分布和时间演变规律,进一步识别了驱动制浆造纸产业碳效率变动的关键因素,为产业政策制定提供了科学依据。其次,结合当前我国经济发展与低碳经济转型的大环境,提出了针对制浆造纸产业的碳减排策略。

双缸液压驱动系统灰色预测模糊PID控制研究

为了提高双缸液压驱动系统非线性变化力的跟踪精度,使驱动力变化相对稳定,设计了灰色预测模糊比例积分微分(PID)控制器,并对驱动力跟踪效果进行仿真验证。为了对双缸液压驱动系统工作原理进行介绍,绘制了双缸液压驱动系统装置简图。针对传统PID控制器进行改进,结合模糊推理和灰色预测理论,设计出灰色模糊PID控制器,并且给出了双缸液压驱动系统控制过程。利用灰色补偿提高控制器的抗干扰能力,采用Matlab软件对双缸液压驱动系统非线性力的变化跟踪进行仿真,与改进前的控制效果进行对比。结果显示:在无干扰环境中,采用PID控制、模糊PID控制和灰色预测模糊PID控制方法,均能提高双缸液压驱动系统力的变化跟踪精度,这3种控制器控制效果相差不大。在有干扰环境中,灰色预测模糊PID控制方法明显优于PID控制和模糊PID控制方法。双缸液压驱动系统采用灰色预测模糊PID控制方法,能够抑制外界波形的干扰,从而提高控制系统的稳定性。

特厚煤层沿空掘巷围岩支卸协同控制技术

针对特厚煤层小煤柱沿空掘巷大范围塑性全煤巷道锚网索的支护难题,以塔山煤矿8204-2小煤柱工作面为工程背景,采用现场实测、理论分析等方法,揭示了锚杆、锚索对沿空大范围塑性全煤巷道的支护机理。锚杆支护主要作用于浅部二次破碎区煤体,形成浅部连续承载结构;锚索主要作用于深部处于三向受力状态的稳定煤体,形成更大范围的连续稳定承载结构;进一步明确了锚杆、锚索有效长度的计算方法,形成了以高预紧力、高强“锚-网-索”支护为基础,以坚硬顶板井下磨料水射流切顶卸压、巷帮大直径钻孔卸压、底板卸压槽卸压为辅的“支卸协同”小煤柱沿空巷道围岩控制技术体系。工程应用结果表明,试验巷道围岩最大变形量小于700 mm,能够满足使用要求。

一种雷达转台双电机驱动系统设计与同步控制方法

作为机械传动系统的一个重要组成,转台被广泛应用于雷达系统中,为满足雷达检测等领域对转台驱动系统惯量、功率、性能方面的要求,提出采用双电机同步驱动转台的方式。利用双电机伺服系统的电消隙原理和差速耦合负反馈的同步控制方法,由控制器将控制量经数/模转换送入驱动器,以实现系统的消隙功能、同步补偿功能,提高转台驱动系统的精度和同步控制性能,并将其运用到雷达转台伺服系统中,结果证明了方法的可行性,能够提高所设计雷达转台双电机驱动系统的精确性。

高速公路立体复合扩容设计的仿真模型研究

针对传统交通仿真技术在高速公路立体复合扩容场景存在评估精度不足、应用效果甚微的问题,提出了一种面向高速公路立体复合扩容设计的仿真模型构建方法。选取深圳市机荷高速改扩建工程为研究对象,梳理路网设施、交通需求数据、驾驶行为模型参数等3大仿真模型建模要素,提出仿真建模的技术流程;对包含互通立交、收费站、上下匝道等重点基础设施的全路网进行仿真建模,基于交通量预测模型获取项目范围的出行OD矩阵,完成交通需求建模;引入驾驶模拟仿真技术,构建高速公路立体复合扩容的驾驶模拟场景,设计并开展驾驶模拟实验,采用K均值聚类算法将驾驶行为划分为激进、保守、正常3个类别,并分别分析驾驶行为特征,据此对仿真驾驶行为模型参数进行标定,提升仿真模型精度。仿真结果表明:该模型构建方法,可以有效标定期望速度、车头时距、临界间隙等参数,从而提升仿真模型分析精度。

基于Pearson相关性分析的双V型永磁同步电机失磁故障动态识别方法

针对电驱动系统用高功率密度永磁驱动电机存在的不可逆退磁问题,以一款8极48槽的双V型永磁同步电机为例对退磁故障的动态识别方法进行了研究。在考虑电机闭合磁路对永磁体退磁故障影响的基础上,通过分析高退磁率电机模型退磁前后的空载和负载参数变化,采用Pearson相关性分析的方法提取了表征退磁故障的特征参量,给出了一种退磁故障的动态识别方法,并分析了转速和电流对特征参量的影响,完成了对退磁故障动态识别方法的修正。通过仿真和实验测试的方法对退磁故障动态识别方法的准确性进行了验证,结果表明,仿真结果的误差为0.68%,实验测试的预测结果最大误差为1.765%,误差均在可接受范围内。

自动化决策系统语境中不作为因果关系之司法证明

智能辅助驾驶等自动化决策系统的成熟引发的证据法问题,是如何运用证据认定“机器的不作为”与损害结果之间具有事实上的因果关系,为此,可引入双重相关性证明理论加以解决。不作为因果关系的实体法构成要件要素包括作为可能性与结果回避的统计概率,其中,结果回避的统计概率建立在作为可能性基础上。实体法上的作为可能性在证据层面对应的待证事实,是因果干预的能力事实和能力的触发条件事实。在进行证据调查时,所有可采纳的证据材料需满足双重相关性要求,即证据材料与待证的能力事实和条件事实的相关性,以及能力及其触发条件与结果得到避免的假设之间的相关性。在进行事实重建时,应运用“二次重建”方法,在第一次重建中,事实认定者必须使用所有可采证据来重建行为人(自动化决策系统)的干预能力和能力的触发条件,而后在第二次重建中,他需要基于这些能力和条件,重建行为人(自动化决策系统)避免结果发生的行动计划、过程及其可能的成效,并根据第二次重建来计算结果回避的统计概率。

基于组合结构的双界面液体透镜的设计与分析

为了提高液体透镜的成像质量和变焦范围,应用介电泳和液压驱动,设计了一款基于组合结构的双界面液体透镜,其主要由介电泳双液体透镜和PDMS薄膜液体透镜组成。首先,在Comsol软件中建立液体透镜模型,研究不同电压下的液滴界面和PDMS薄膜的面型变化,并导出两个曲面的面型数据。其次,在Matlab软件中,采用非球面表达式进行拟合,得到不同电压下液滴的界面和薄膜的面型图及其相应的非球面系数。最后,在Zemax软件中,构建出相应的双界面组合液体透镜光学模型,像面选取为高斯像面,并通过相应器件的制备与初步实验研究,将仿真结果和实验数据进行比较分析。结果表明,所设计的基于组合结构的双界面液体透镜仿真和实验的变焦范围基本一致,同时实验获得的变焦比可达2.1254、成像分辨率最大可达101.5937 lp/mm。本文设计的基于组合结构的双界面液体透镜具有结构简单紧凑、界面可调控性强、成像分辨率高的优点。

创新驱动政策赋能新质生产力发展——来自国家自主创新示范区的证据

将国家自主创新示范区政策视为创新驱动赋能的准自然实验,基于2004—2022年城市面板数据,采用渐进双重差分法评估国家自主创新示范区政策对城市新质生产力发展的影响效应。研究发现,以国家自主创新示范区为代表的创新驱动政策能够显著促进城市新质生产力发展。机制检验结果表明,创新驱动政策是技术创新的“助推器”、结构变迁的“奠基石”,而技术创新与结构变迁是促进城市新质生产力发展的重要抓手,以国家自主创新示范区为代表的创新驱动政策能够通过绿色技术创新和产业结构变迁赋能新质生产力发展。异质性分析结果表明,不同区域的国家自主创新示范区均有效赋能新质生产力发展,同时对“新料质”劳动对象的促进作用更显著,并且城市的新质生产力水平越高则政策赋能效果越好。拓展分析结果表明,创新驱动政策存在叠加效应,同时能有效赋能制造业企业创新实现“提质增量”。