High-intensity spatial-mode steerable frequency up-converter toward on-chip integration

Integrated photonic devices are essential for on-chip optical communication,optical-electronic systems,and quantum information sciences.To develop a high-fidelity interface between photonics in various frequency domains without disturbing their quantum properties,nonlinear frequency conversion,typically steered with the quadratic(χ2)process,should be considered.Furthermore,another degree of freedom in steering the spatial modes during theχ2 process,with unprecedent mode intensity is proposed here by modulating the lithium niobate(LN)waveguide-based inter-mode quasi-phasematching conditions with both temperature and wavelength parameters.Under high incident light intensities(25 and 27.8 dBm for the pump and the signal lights,respectively),mode conversion at the sum-frequency wavelength with sufficient high output power(−7–8 dBm)among the TM01,TM10,and TM00 modes is realized automatically with characterized broad temperature(ΔT≥8°C)and wavelength windows(Δλ≥1 nm),avoiding the previous efforts in carefully preparing the signal or pump modes.The results prove that high-intensity spatial modes can be prepared at arbitrary transparent wavelength of theχ2 media toward on-chip integration,which facilitates the development of chip-based communication and quantum information systems because spatial correlations can be applied to generate hyperentangled states and provide additional robustness in quantum error correction with the extended Hilbert space.

A Novel Integrated Stability Control Based on Differential Braking and Active Steering for Four-axle Trucks

Di erential braking and active steering have already been integrated to overcome their shortcomings. However, existing research mainly focuses on two-axle vehicles and controllers are mostly designed to use one control method to improve the other. Moreover, many experiments are needed to improve the robustness; therefore, these control methods are underutilized. This paper proposes an integrated control system specially designed for multi-axle vehicles, in which the desired lateral force and yaw moment of vehicles are determined by the sliding mode control algorithm. The output of the sliding mode control is distributed to the suitable wheels based on the abilities and potentials of the two control methods. Moreover, in this method, fewer experiments are needed, and the robustness and simultaneity are both guaranteed. To simplify the optimization system and to improve the computation speed, seven simple optimization subsystems are designed for the determination of control outputs on each wheel. The simulation results show that the proposed controller obviously enhances the stability of multi-axle trucks. The system improves 68% of the safe velocity, and its performance is much better than both di erential braking and active steering. This research proposes an integrated control system that can simultaneously invoke di erential braking and active steering of multi-axle vehicles to fully utilize the abilities and potentials of the two control methods.

Nonlinear Derivative and Integral Sliding Control for Tracked Vehicle Steering with Hydrostatic Drive

In the steering process of tracked vehicle with hydrostatic drive,the motion and resistance states of the vehicle are always of uncertain and nonlinear characteristics,and these states may undergoe large-scale changes.Therefore,it is significant to enhance the steering stability of tracked vehicle with hydrostatic drive to meet the need of future battlefield.In this paper,a sliding mode control algorithm is proposed and applied to achieve desired yaw rates.The speed controller and the yaw rate controller are designed through the kinematics and dynamics analysis.In addition,the nonlinear derivative and integral sliding mode control algorithm is designed,which is supposed to efficiently reduce the integration saturation and the disturbances from the unsmooth road surfaces through a conditional integrator approach.Moreover,it improves the response speed of the system and reduces the chattering by the derivative controller.The hydrostatic tracked vehicle module is modeled with a multi-body dynamic software RecurDyn and the steering control strategy module is modeled by MATLAB/Simulink.The co-simulation results of the whole model show that the control strategy can improve the vehicle steering response speed and also ensure a smooth control output with small chattering and strong robustness.

A 12-Bit 1-Gsample/s Nyquist Current-Steering DAC in 0.35 µm CMOS for Wireless Transmitter

The present work deals with 12-bit Nyquist current-steering CMOS digital-to-analog converter (DAC) which is an essential part in baseband section of wireless transmitter circuits. Using oversampling ratio (OSR) for the proposed DAC leads to avoid use of an active analog reconstruction filter. The optimum segmentation (75%) has been used to get the best DNL and reduce glitch energy. This segmentation ratio guarantees the monotonicity. Higher performance is achieved using a new 3-D thermometer decoding method which reduces the area, power consumption and the number of control signals of the digital section. Using two digital channels in parallel, helps reach 1-GSample/s frequency. Simulation results show that the spurious- free-dynamic-range (SFDR) in Nyquist rate is better than 64 dB for sampling frequency up to 1-GSample/s. The analog voltage supply is 3.3 V while the digital part of the chip operates with only 2.4 V. Total power consumption in Nyquist rate measurement is 144.9 mW. The chip has been processed in a standard 0.35 μm CMOS technology. Active area of chip is 1.37 mm2.

Simulation on Driving System Used for Differential Steering of Electric Scooter

To investigate the feasibility and effectiveness of the designed control system used for driving and steering of an electric scooter,a model of differential steering was developed.The function of electronic differential steering was realized by controlling the speed of right or left wheel and the corresponding speed difference.The control system was simulated with MATLAB/SIMULINK and ADAMS.It is found that the motor load torque is proportional to the tire vertical force,so the adhesive capacity is met.The electric scooter can operate stably on the slope road at a speed of more than 1.5m/s and turn stably at yawing velocities of 10°and 90°per second.

On the Existence of an Optimal Control of Ship Automatic Steering Instruments

The existence of linear quadratic optimal control of ship automatic steering instruments is studied. Firstly, the sufficient conditions for the quadratic integrability of the solutions of linear second order time-variant differential equations are developed. Secondly, the optimal control form of the ship automatic steering instrument is obtained by using the dynamic programming method, which guarantees a minimal ship sway range, during long-distance navigation, by using as little energy as possible. Finally, based on the above mentioned sufficient conditions, the conditions for the realization of optimal control are obtained, which provides a foundation for choosing the weighted coefficients for optimal control in engineering.

四川盆地深层页岩气钻井关键技术新进展及发展展望

四川盆地页岩气资源丰富,目前深层页岩气已成为该盆地天然气增储上产的重点领域,但随着埋深增加和构造背景变化,地质工程条件将更加复杂,钻井过程中将面临井漏风险高、井下工具高温易失效、水平井轨迹控制难度大等技术难题。为此,在系统分析已完钻井实钻数据的基础上,依据深层页岩气区块地质工程特征,系统梳理了影响安全优快钻井的关键技术难点,形成了以地质工程一体化导向技术、钻井提速技术、防漏治漏与复杂防治技术为主体的深层页岩气安全优快钻井关键技术系列。研究结果表明:(1)以精细地质建模优选地质工程“双甜点”、实时靶体追踪为主的地质工程一体化导向技术,实现了地质目标的精准优选和精确追踪;(2)以“高效PDC钻头选型+个性化优化+大扭矩螺杆”高效破岩技术、“MSE+CCS”参数实时优化技术、油基钻井液地面降温+高温旋转导向技术为主的钻井提速技术,实现了页岩气钻井提速提效;(3)以井壁稳定性评价、裂缝性漏层识别、井漏与复杂防治为主的复杂防治技术,从源头降低了井下漏失和卡钻风险。结论认为:(1)形成的深层页岩气安全优快钻井技术,显著提高了机械钻速和铂金靶体钻遇率,在现场规模化推广应用200余口井,单井平均钻井周期降低42.7%,钻井提速效果显著,有力支撑了深层页岩气效益规模开发;(2)深层页岩气钻井将聚焦“地质工程一体化、水平段一趟钻、防漏治漏及智能钻井决策”等方面的技术攻关。

线控主动四轮转向汽车控制策略研究

目的针对线控四轮转向汽车横向稳定性不足及控制鲁棒性差等问题,提出一种主动转向反馈控制策略。方法使用Simulink搭建线控转向系统转向执行机构动力学模型,将MATLAB/Simulink与Carsim联合仿真,建立线控四轮转向整车模型;基于二自由度模型分析横摆角速度和质心侧偏角对汽车稳定性的影响,推导理想的横摆角速度和质心侧偏角;以横摆角速度增益恒定为依据设计理想传动比,得到期望前轮转角,以横摆角速度误差为控制量设计模糊控制器得到附加前轮转角对期望转角实时修正,实现前轮主动转向;针对横摆角速度和质心侧偏角与理想值之间的误差,加权得到稳定性控制目标;设计自适应积分滑模反馈控制策略输出后轮转角,对理想值进行跟踪,实现后轮主动转向。结果仿真实验结果表明:所搭建的线控转向系统能够准确反映汽车动力学特性。相比无控制的机械前轮转向汽车与横摆反馈控制的四轮转向汽车,线控主动四轮转向汽车在双移线工况下将质心侧偏角控制在0值附近波动,横摆角速度跟踪误差控制在1.149 deg/s以内;在角阶跃工况下将质心侧偏角稳态值控制在0.065 deg,横摆角速度稳态值误差为0.074 deg/s。结论线控主动四轮转向控制策略在双移线和角阶跃工况下控制效果显著,鲁棒性能好,能有效提高汽车的操纵稳定性和主动安全性。

床椅一体化机器人设计与实现

针对床椅机器人在室内狭小空间灵活行走的问题,研制一款四轮独立驱动转向的床椅一体化机器人。根据室内狭小空间的转向需求,确定了底盘总体布局方案和主要技术参数。对重要部件进行了理论计算、有限元分析,对驱动轮支架进行了应力及形变分析;在ADAMS软件中建立了床椅机器人的动力学仿真模型,进行了稳定性分析。仿真结果表明,驱动轮支架的强度和刚度均满足设计要求,床椅机器人的各项指标符合国家相关标准的规定。样机试验进一步验证了仿真分析的结果,确认了床椅一体化机器人的稳定性、越障性能和在室内狭小空间的转向性能。

夏子街油田X50区块随钻地层边界探测工具应用

夏子街油田X50井区受构造复杂影响,水平井钻井过程中出现钻入储层上部或者下部低钻速泥岩中造成井壁不稳定、卡钻、水平段井斜调整困难、追不到目的层而导致侧钻等问题。针对存在问题,斯伦贝谢公司结合本区块地质及储层的电阻率特征,进行旋转导向配合边界探测工具的可行性研究。边界探测工具探测深度较深,是具有方向性测量的随钻电磁感应测井工具,应用实时导向软件对测量参数进行反演,估算出工具到地层边界的距离以及地层边界的延伸方向。现场实践表明,在第一口水平井SP-2井侧钻过程中,使用边界探测工具能够提前预判储层顶和底部泥岩的位置,并根据轨迹与边界的距离进行实时调整,避免钻遇泥岩,机械钻速提升近两倍,储层钻遇率达100%,减少了循环和决策时间,提高了钻井效率。SP-2井侧钻成功为后期新区开发提供了技术保障,也为实现工程地质一体化奠定了基础。

Photonic integrated optical phased arrays and their applications[Invited]

In recent years,optical phased arrays(OPAs)have attracted great interest for their potential applications in light detection and ranging(Li DAR),free-space optical communications(FSOs),holography,and so on.Photonic integrated circuits(PICs)provide solutions for further reducing the size,weight,power,and cost of OPAs.In this paper,we review the recent development of photonic integrated OPAs.We summarize the typical architecture of the integrated OPAs and their performance.We analyze the key components of OPAs and evaluate the figure of merit for OPAs.Various applications in Li DAR,FSO,imaging,biomedical sensing,and specialized beam generation are introduced.

基于KFESO的四轮主动转向积分滑模控制

为消除参数不确定和外部不确定扰动对四轮转向车辆操纵稳定性的影响,提出了一种基于卡尔曼扩张状态观测器的四轮主动转向非线性积分滑模控制(KFESO-ISMC)方法。首先设计了一种卡尔曼扩张状态观测器(KFESO),实现了车辆状态观测以及外部扰动估计,克服了传统卡尔曼滤波算法对模型参数精度的依赖的缺点。其次为降低外部扰动引起的车辆状态的跟踪误差,将KFESO观测的系统总扰动补偿到控制输入;并为实现全局鲁棒控制和抑制积分饱和现象,设计了四轮主动转向非线性积分滑模控制方法。最后,硬件在环试验结果表明:在存在内外部不确定扰动情况下,KFESO观测器具有较高的观测精度;在四轮主动转向操纵稳定性的控制方面,KFESOISMC方法相比LQR和ISMC方法具优良的抗扰性能。

基于Simulation X的多轴转向系统功能安全仿真分析

基于ISO 26262《道路车辆功能安全》的标准要求,对特种车的多轴电液转向系统进行分析,以提高系统的安全性和可靠性。运用Simulation X软件建立详细的多轴特种车仿真模型,通过模拟故障模式注入进行仿真试验。对仿真结果和数据进行分析,评估得到故障的严重性、暴露度和可控性,从而确定相应的汽车安全完整性等级。基于故障注入仿真的汽车功能安全分析方法,在系统早期设计阶段可以作为评估架构安全性的重要手段。

集成电路技术在拖拉机系统优化中的应用研究

以拖拉机精准作业导航控制为研究对象,利用集成电路技术对拖拉机导航控制系统进行设计,将拖拉机导航控制终端、转向控制器以及作业提升机构之间的通讯数据通过CAN总线集成电路进行连接,分别设计拖拉机精准作业导航控制系统硬件电路和控制系统通讯软件。为验证CAN总线集成电路在拖拉机导航控制终端与导航控制器之间的通讯有效性,在农田环境内进行导航路径规划验证,结果表明:导航控制系统实际运行轨迹X方向与理论路径偏差值为1m,Y方向产生2m偏差;拖拉机实际运行距离为99.02m,与理论规划路径总偏差值为0.98m,运行距离误差比例为0.98%,运行方向偏差1.16°。

车辆线控转向系统的永磁同步电机谐波抑制策略

为解决车辆线控转向系统的永磁同步电机因谐波电流引起的相电流畸变问题,提高车辆横向控制的跟随性和回正力矩估算的准确性,设计了基于扩张状态观测器和积分滑模控制器的永磁同步电机谐波抑制策略。使用扩张状态观测器实现对电机基波电流环的dq电流估算,完成解耦及扰动补偿,根据从估算电流中提取的5、7次谐波电流设计积分滑模控制器实现对谐波电流的解耦与抑制。通过Carsim和Matlab/Simulink仿真平台搭建电机对拖和整车仿真模型,结果表明,该策略对额定转速和超额定转速时的5、7次谐波电流有良好抑制能力,可以提高电机转角控制的精确性和回正力矩估算的准确性。

基于规则的多轴特种车辆稳定性集成控制

为提升多轴特种车辆的主动安全性与操纵稳定性,以某重型5轴特种车辆为研究对象,基于自适应协调控制策略,设计了集成主动后轮转向(ARS)与差动制动力矩分配(DBTD)的分层稳定性集成控制策略。决策层基于规则决策出ARS与DBTD子控制系统的协调控制指令;分配层基于前馈+反馈控制策略实现主动转向轮转向角的分配;基于滑膜控制与既定规则实现车轮差动制动力矩的分配。通过Trucksim与Simulink联合仿真对所提控制策略的控制效果进行验证,对比分析了高速高附转向与低速低附转向2种极限工况下稳定性控制车辆与无控制车辆的运动状态。结果表明:在集成控制系统控制下的车辆,对于高速高附工况,车辆的横摆角速度与质心侧偏角的幅值相比于无控制车辆分别降低了46%与63%,对于低速低附工况,车辆的横摆角速度与质心侧偏角的幅值相比于无控制车辆分别降低了47%与58%,集成控制系统能有效提升车辆高速高附转向时的行驶稳定性与低速低附转向时的转向灵敏度和路径跟随性能。

泌阳凹陷页岩油水平井随钻定测录导一体化模式探索

水平井是油藏开发实现少井高产、一井多靶、降本提效的主要手段之一,但泌阳凹陷核三段页岩油藏地质条件复杂,不利于水平井钻井提速提效。文中以地震、测井、录井及分析化验资料为基础,通过对泌阳凹陷核三段页岩油藏地质特征剖析,梳理了页岩油水平井钻井施工难点,从一体化组织运行、一体化协调施工及一体化支撑保障等方面阐述了泌阳凹陷定测录导一体化模式的探索及应用。研究表明:泌阳凹陷核三段页岩油层存在局部微构造及断层发育、地层倾角变化快等特点,同时其地震资料品质差。这些导致钻井施工中靶点预测及井眼轨迹调整难度大,影响随钻资料评价的准确性。通过优选定向系统、钻具组合及高效钻头,应用正反演结合测井数据及校正后的元素录井资料综合评价,实现了井眼轨迹优化着陆及长水平段持续追踪。随钻定测录导一体化模式在YYY1HF井进行了应用,提高了机械钻速,目的层钻遇率达100%,助力了区域页岩油水平井优快钻井,对于水平井优快钻井技术的发展及页岩油高效开发具有重要的意义。

超长距离沉管浮运技术研究及应用

深中通道沉管预制场位于珠海市桂山岛,与隧址区距离约为50 km,这是目前国内最长的沉管拖航距离,并且需要穿越多个社会航道。经过方案比选选择了浮运安装一体船的拖航方式,并开展了船管连接、航道设计,并针对不同的航道特点,选择不同的浮运操控方式,减少了社会航道的航道管控时间,保证了浮运的安全,可为类似项目提供参考。

分布式驱动电动汽车四轮转向与横摆力矩集成控制研究

针对四轮独立驱动与独立转向的分布式驱动电动汽车稳定性控制问题,提出了一种四轮转向与横摆力矩集成控制策略。采用分层控制结构,基于模糊理论设计上层控制器,根据期望横摆角速度、期望质心侧偏角与实际值的偏差,计算附加后轮转角和附加横摆力矩;下层控制器包括四轮转角控制器和四轮力矩分配器,附加后轮转角控制器根据转向盘转角和车速分别采用比例前馈加模糊反馈或阿克曼转向进行附加后轮转角控制,四轮力矩分配器根据附加横摆力矩需求采用二次规划算法对四轮力矩进行优化分配。选取典型实验工况,通过联合仿真实验对后轮转向与横摆力矩集成控制策略进行验证。结果表明:集成控制策略能有效提高分布式驱动电动汽车稳定性。

旋转导向系统中非接触电能与信号一体化传输技术

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