期刊文献+
共找到19,268篇文章
< 1 2 250 >
每页显示 20 50 100
Hybrid Controller for Steady Speed of Agricultural Machinery on Slopes
1
作者 WU Caicong XU Haisong GAO Xingyu 《农业机械学报》 北大核心 2026年第2期416-426,共11页
Steady speed control of agricultural machinery can improve operating quality and efficiency.To address the impact of farmland slope variations on the speed stability of unmanned operation agricultural machinery,a hybr... Steady speed control of agricultural machinery can improve operating quality and efficiency.To address the impact of farmland slope variations on the speed stability of unmanned operation agricultural machinery,a hybrid control method was proposed.This method included a hybrid controller composed of a slope-based controller and a proportional-integral-derivative(PID)controller.The speed of agricultural machinery was influenced by longitudinal forces,which were divided into two parts:one part was slope-related forces and conventional resistance,and the other was hard-to-estimate forces,such as sliding friction.For the first part,a slope-based controller was designed;for the second part,a PID controller was implemented.By combining these two controllers,the system can dynamically adjust the throttle opening and the brake master cylinder pressure,ensuring steady speed travel on sloping farmland.Simulation tests at a target speed of 7 km/h demonstrated that the proposed controller maintained a stable speed,achieving a root mean square error of 0.13 km/h and a mean absolute percentage error of 1.6%.Field tests on a practical experimental platform validated the method’s effectiveness,with results showing consistent control performance across varying slope conditions.The proposed controller demonstrated superior control performance.Experimental data verified that this method can achieve precise control of the agricultural machinery’s movement speed,meeting the stability requirements for agricultural operations. 展开更多
关键词 farmland slope PID controller steady speed control agricultural machinery unmanned operation
在线阅读 下载PDF
A Comprehensive Review of Torque and Speed Control Strategies for Switched Reluctance Motor Drives 被引量:1
2
作者 Sreeram K Preetha P K +1 位作者 Javier Rodríguez-García Carlosálvarez-Bel 《CES Transactions on Electrical Machines and Systems》 2025年第1期46-75,共30页
Switched Reluctance Motors(SRMs),outfitted with rugged construction,good speed range,high torque density,and rare earth-free nature that outweigh induction motors(IM)and permanent magnet synchronous motor(PMSM),afford... Switched Reluctance Motors(SRMs),outfitted with rugged construction,good speed range,high torque density,and rare earth-free nature that outweigh induction motors(IM)and permanent magnet synchronous motor(PMSM),afford a broad range of applications in the domain of electric vehicles(EVs).Standard copper magnetic wire and low-carbon steel laminations are used to construct SRMs,which give them high efficiency in the range of 85-95%.Despite SRM's desirable features over traditional motor-speed drives,high torque ripples and radial distortions constrain their deployment in EVs.Precise rotor position is imperative for effective management of the speed and torque of SRMs.This paper provides an illustrative compendium on review of the torque-speed control and ripple mitigation techniques using design enhancements and control methods for SRM drives for EV applications.The various schemes were evaluated on their performance metricsoperational speed range,control complexity,practical realization,need for pre-stored parameters(look-up tables of current,inductance and torque profiles)and motor controller memory requirements.The findings provide valuable insights into balancing the gains and trade-offs associated with EV applications.Furthermore,they pinpoint opportunities for enhancement by analyzing the cost and technical aspects of different SRM controllers. 展开更多
关键词 Electric vehicles Switched reluctance motor Speed control Torque control Traction motor Torque ripple
在线阅读 下载PDF
Challenges and suggestions for high-speed boundary layer transition control using surface microstructure 被引量:1
3
作者 Jisen YUAN Shenghao YU Zhansen QIAN 《Chinese Journal of Aeronautics》 2025年第4期7-9,共3页
Due to the coexistence of compressibility,viscosity,and threedimensional effects,laminar flow is difficult to maintain for high-speed boundary layer on complex geometries.The unstable disturbance waves in the boundary... Due to the coexistence of compressibility,viscosity,and threedimensional effects,laminar flow is difficult to maintain for high-speed boundary layer on complex geometries.The unstable disturbance waves in the boundary layer are excited and rapidly increase during the receptivity process,so sufficiently large Reynolds stress causes the basic flow velocity profile to change,and the formation of turbulence is inevitable. 展开更多
关键词 high speed boundary layer large reynolds stress transition control surface microstructure unstable disturbance waves CHALLENGES suggestions boundary layer
原文传递
Idle speed control of proton exchange membrane fuel cell system via extended Kalman filter observer
4
作者 ZHAO Hong-hui DING Tian-wei +4 位作者 WANG Yi-lin HUANG Xing DU Jing HAO Zhi-qiang MIN Hai-tao 《控制理论与应用》 北大核心 2025年第8期1615-1624,共10页
When the proton exchange membrane fuel cell(PEMFC)system is running,there will be a condition that does not require power output for a short time.In order to achieve zero power output under low power consumption,it is... When the proton exchange membrane fuel cell(PEMFC)system is running,there will be a condition that does not require power output for a short time.In order to achieve zero power output under low power consumption,it is necessary to consider the diversity of control targets and the complexity of dynamic models,which brings the challenge of high-precision tracking control of the stack output power and cathode intake flow.For system idle speed control,a modelbased nonlinear control framework is constructed in this paper.Firstly,the nonlinear dynamic model of output power and cathode intake flow is derived.Secondly,a control scheme combining nonlinear extended Kalman filter observer and state feedback controller is designed.Finally,the control scheme is verified on the PEMFC experimental platform and compared with the proportion-integration-differentiation(PID)controller.The experimental results show that the control strategy proposed in this paper can realize the idle speed control of the fuel cell system and achieve the purpose of zero power output.Compared with PID controller,it has faster response speed and better system dynamics. 展开更多
关键词 proton exchange membrane fuel cell idle speed control zero power output output power nonlinear model extended Kalman filter observer
在线阅读 下载PDF
Method Design and Field Experiment Validation of Predictive Fuel-saving Cruise Control Based on Cloud Control Platform
5
作者 Keke Wan Shuyan Li +2 位作者 Bolin Gao Fachao Jiang Yanbin Liu 《Chinese Journal of Mechanical Engineering》 2025年第5期297-316,共20页
Predictive cruise control(PCC)is an intelligence-assisted control technology that can significantly improve the overall performance of a vehicle by using road and traffic information in advance.With the continuous dev... Predictive cruise control(PCC)is an intelligence-assisted control technology that can significantly improve the overall performance of a vehicle by using road and traffic information in advance.With the continuous development of cloud control platforms(CCPs)and telematics boxes(T-boxes),cloud-based predictive cruise control(CPCC)systems are considered an effective solution to the problems of map update difficulties and insufficient computing power on the vehicle side.In this study,a vehicle-cloud hierarchical control architecture for PCC is designed based on a CCP and T-box.This architecture utilizes waypoint structures for hierarchical and dynamic cooperative inter-triggering,enabling rolling optimization of the system and commending parsing at the vehicle end.This approach significantly improves the anti-interference capability and resolution efficiency of the system.On the CCP side,a predictive fuel-saving speed-planning(PFSP)algorithm that considers the throttle input,speed variations,and time efficiency based on the waypoint structure is proposed.It features a forward optimization search without requiring weight adjustments,demonstrating robust applicability to various road conditions and vehicles equiped with constant cruise(CC)system.On the vehicle-side T-box,based on the reference control sequence with the global navigation satellite system position,the recommended speed is analyzed and controlled using the acute angle principle.Through analyzing the differences of the PFSP algorithm compared to dynamic programming(DP)and Model predictive control(MPC)algorithms under uphill and downhill conditions,the results show that the PFSP achieves good energy-saving performance compared to CC without exhibiting significant speed fluctuations,demonstrating strong adaptability to the CC system.Finally,by building an experimental platform and running field tests over a total of 2000 km,we verified the effectiveness and stability of the CPCC system and proved the fuel-saving performance of the proposed PFSP algorithm.The results showed that the CPCC system equipped with the PFSP algorithm achieved an average fuel-saving rate of 2.05%-4.39%compared to CC. 展开更多
关键词 Predictive cruise control Cloud control platform Hierarchical control architecture Fuel-saving speed planning
在线阅读 下载PDF
Enhanced interconnection and damping assignment passivity-based control for PM synchronous motors
6
作者 Mohamed Azzi Lotfi Baghli +2 位作者 Ehsan Jamshidpour Phatiphat Thounthong Noureddine Takorabet 《Global Energy Interconnection》 2025年第4期657-667,共11页
Permanent Magnet Synchronous Motors(PMSMs)are widely employed in high-performance drive applications due to their superior efficiency and dynamic capabilities.However,their control remains challenging owing to nonline... Permanent Magnet Synchronous Motors(PMSMs)are widely employed in high-performance drive applications due to their superior efficiency and dynamic capabilities.However,their control remains challenging owing to nonlinear dynamics,parameter variations,and unmeasurable external disturbances,particularly load torquefluctuations.This study proposes an enhanced Interconnection and Damp-ing Assignment Passivity-Based Control(IDA-PBC)scheme,formulated within the port-controlled Hamiltonian(PCH)framework,to address these limitations.A nonlinear disturbance observer is embedded to estimate and compensate,in real time,for lumped mis-matched disturbances arising from parameter uncertainties and external loads.Additionally,aflatness-based control strategy is employed to generate the desired current references within the nonlinear drive system,ensuring accurate tracking of time-varying speed commands.This integrated approach preserves the system’s energy-based structure,enabling systematic stability analysis while enhancing robustness.The proposed control architecture also maintains low complexity with a limited number of tunable parameters,facilitating practical implementation.Simulation and experimental results under various operating conditions demonstrate the effectiveness and robustness of the proposed method.Comparative analysis with conventional proportional-integral(PI)control and standard IDA-PBC strategies confirms its capability to handle disturbances and maintain dynamic performance. 展开更多
关键词 Hamiltonian energy control Interconnection and damping assignment passivity-based control IDA-PBC Motor drives Permanent-magnet synchronous machine(PMSM) Speed control
在线阅读 下载PDF
Aerodynamic/control coupling optimization of reentry vehicle under wide speed range
7
作者 Lulu Jiang Chao Dong +1 位作者 Xin Pan Gang Chen 《Acta Mechanica Sinica》 2025年第5期65-78,共14页
The high-speed reentry vehicle operates across a broad range of speeds and spatial domains,where optimal aerodynamic shapes for different speeds are contradictory.This makes it challenging for a single-Mach optimizati... The high-speed reentry vehicle operates across a broad range of speeds and spatial domains,where optimal aerodynamic shapes for different speeds are contradictory.This makes it challenging for a single-Mach optimization design to meet aerodynamic performance requirements throughout the vehicle’s flight envelope.Additionally,the strong coupling between aerodynamics and control adds complexity,as fluctuations in aerodynamic parameters due to speed variations complicate control system design.To address these challenges,this study proposes an aerodynamic/control coupling optimization design approach.This method,based on aerodynamic optimization principles,incorporates active control technology,treating aerodynamic layout and control system design as primary components during the conceptual design phase.By integrating the design and evaluation of aerodynamics and control,the approach aims to reduce design iterations and enhance overall flight performance.The comprehensive design of the rotary reentry vehicle,using this optimization strategy,effectively balances performance at supersonic and hypersonic speeds.The results show that the integrated design model meets aerodynamic and control performance requirements over a broader range of Mach numbers,preventing performance degradation due to deviations from the design Mach number,and providing a practical solution for high-speed reentry vehicle design. 展开更多
关键词 Aerodynamic/control coupling Surrogate-based optimization High-speed vehicle Wide speed range HYPERSONIC
原文传递
A new fixed-depth suspension control algorithm for mobile marine seismometer and its testing results
8
作者 Fei Hou Jiabiao Li +2 位作者 Xinke Zhu Weiwei Ding Zhiteng Yu 《Acta Oceanologica Sinica》 2025年第2期91-103,共13页
A mobile marine seismometer(MMS)is a vertical underwater vehicle that detects ocean seismic waves.One of the critical operational requirements for an MMS is that it remains suspended at a desired depth.This article ai... A mobile marine seismometer(MMS)is a vertical underwater vehicle that detects ocean seismic waves.One of the critical operational requirements for an MMS is that it remains suspended at a desired depth.This article aimed to propose a fixed-depth suspension control for the MMS with a limited onboard energy supply.The research team established a kinematic model to analyze fluctuations in the vertical motion of the MMS and the delayed response of the system.We ascertained a direct one-to-one correlation between the displacement volume of the mobile ocean seismic instrument and the depth at which it reaches a state of neutral buoyancy(commonly referred to as the hover depth).A fixed-depth control algorithm was introduced,allowing a gradual approach to the necessary displacement volume to reach the desired suspension depth.The study optimized the boundary conditions to reduce unnecessary adjustments and mitigate the time delay caused by the instrument’s inertia,thereby significantly minimizing energy consumption.This method does not require calculating the hydrodynamic parameters or transfer functions of the MMS,thereby considerably reducing the implementation complexity.In the three-month sea trial in the South China Sea,the seismic instrument was set to hover at 800 m,with a permissible fluctuation of±100 m,operating on a seven-day cycle.The experimental results show that the seismic instrument has an average hover error of 34.6 m,with a vertical drift depth of 29.6 m per cycle,and the buoyancy adjustment system made six adjustments,indicating that our proposed control method performs satisfactorily.In addition,this method provides new insights for the fixed-depth control of other ocean observation devices that rely on buoyancy adjustment. 展开更多
关键词 mobile marine seismometer fixed-depth control algorithm low buoyancy-adjustment cost faster convergence speed
在线阅读 下载PDF
Autonomous Navigation Algorithm for Underactuated Unmanned Surface Vehicle Based on Model Predictive Control
9
作者 CHEN Guoquan LI Yuqin +1 位作者 HUANG Zike YANG Shenhua 《Journal of Shanghai Jiaotong university(Science)》 2025年第6期1255-1264,共10页
To achieve the track following and collision avoidance of underactuated unmanned surface vehicle(USV),autonomous navigation model based on model predictive control is established by including the track offset,speed va... To achieve the track following and collision avoidance of underactuated unmanned surface vehicle(USV),autonomous navigation model based on model predictive control is established by including the track offset,speed variation and rule compliance as the evaluation functions and including the ship domain of dynamic/static navigation obstacles and the mechanical characteristics limitation as constraints.The effectiveness of the model for autonomous navigation of USV in the situation of multi-ship encounters and in the complex waters with both dynamic and static obstructions is verified by several groups of simulation work.The simulation results show that the proposed model can realize the autonomous navigation of the underactuated USV under the complex waters. 展开更多
关键词 underactuated unmanned surface vehicle(USV) model predictive control track offset speed variation rule compliance
原文传递
Optimizing risk management for post-amputation wound complications in diabetic patients: Focus on glycemic and immunosuppressive control
10
作者 Zhi-Peng Li Jin-Ke Sun +1 位作者 Wei-Ping Fu Chang-Jiang Zhang 《World Journal of Diabetes》 2025年第3期277-283,共7页
This study highlights the importance of identifying and addressing risk factors associated with wound complications following transtibial amputation in diabetic patients.These amputations,often necessitated by severe ... This study highlights the importance of identifying and addressing risk factors associated with wound complications following transtibial amputation in diabetic patients.These amputations,often necessitated by severe diabetic foot ulcers,carry significant risks of postoperative complications such as infection and delayed wound healing.Elevated hemoglobin A1c levels,indicative of poor glycemic control,and a history of kidney transplantation,due to required immunosuppressive therapy,are key factors influencing these outcomes.This paper emphasizes the need for enhanced glycemic management and personalized postoperative care,particularly for immunocompromised individuals,to minimize complications and improve patient prognosis.Future research should focus on prospective studies to validate targeted interventions and optimize care strategies,ultimately aiming to reduce the healthcare burden associated with diabetic foot complications. 展开更多
关键词 Transtibial amputation Diabetic foot Wound complications Risk factors Glycemic control Hemoglobin A1c Immunosuppressive therapy Kidney transplantation Personalized care Postoperative outcomes
暂未订购
Osteocytic vinculin controls bone mass by modulating Mef2c-driven sclerostin expression in mice
11
作者 Yishu Wang Jianmei Huang +7 位作者 Sixiong Lin Lei Qin Dingyu Hao Peijun Zhang Shaochuan Huo Xuenong Zou Di Chen Guozhi Xiao 《Bone Research》 2025年第5期1282-1294,共13页
The focal adhesion(FA)is the structural basis of the cell-extracellular matrix crosstalk and plays important roles in control of organ formation and function.Here we show that expression of FA protein vinculin is dram... The focal adhesion(FA)is the structural basis of the cell-extracellular matrix crosstalk and plays important roles in control of organ formation and function.Here we show that expression of FA protein vinculin is dramatically reduced in osteocytes in patients with aging-related osteoporosis.Vinculin loss severely impaired osteocyte adhesion and dendrite formation.Deleting vinculin using the mouse 10-kb Dmp1-Cre transgenic mice causes dramatic bone loss in the weight-bearing long bones and spine,but not in the skull,in both young and aged mice by impairing osteoblast formation and function without markedly affecting bone resorption.Vinculin loss impairs the anabolic response of skeleton to mechanical loading in mice.Vinculin knockdown increases,while vinculin overexpression decreases,sclerostin expression in osteocytes without impacting expression of Mef2c,a major transcriptional regulator of the Sost gene,which encodes sclerostin.Vinculin interacts with Mef2c and retains the latter in the cytoplasm.Thus,vinculin loss enhances Mef2c nuclear translocation and binding to the Sost enhancer ECR5 to promote sclerostin expression in osteocytes and reduces bone formation.Consistent with this notion,deleting Sost expression in osteocytes reverses the osteopenic phenotypes caused by vinculin loss in mice.Finally,we find that estrogen is a novel regulator of vinculin expression in osteocytes and that vinculin-deficient mice are resistant to ovariectomy-induced bone loss.Thus,we demonstrate a novel mechanism through which vinculin inhibits the Mef2c-driven sclerostin expression in osteocytes to promote bone formation. 展开更多
关键词 focal adhesion fa mef c driven sclerostin expression aging related osteoporosis osteocytic vinculin osteocyte adhesion bone loss control organ formation functionhere focal adhesion
暂未订购
基于VSD-MPC的主动悬架预瞄控制策略
12
作者 赵健 周文博 +5 位作者 王月 朱冰 陈志成 韩嘉懿 张培兴 宋东鉴 《汽车工程》 北大核心 2026年第1期146-155,共10页
针对主动悬架预瞄控制策略对车速适应性弱的问题,提出一种基于变速离散模型预测控制(variable speed discrete-model predictive control,VSD-MPC)的主动悬架预瞄控制策略。首先,通过时域转换方法设计一种车速自适应路面高程信息采样机... 针对主动悬架预瞄控制策略对车速适应性弱的问题,提出一种基于变速离散模型预测控制(variable speed discrete-model predictive control,VSD-MPC)的主动悬架预瞄控制策略。首先,通过时域转换方法设计一种车速自适应路面高程信息采样机制,匹配不同车速下主动悬架对控制周期内所需路面信息的变化需求。其次,提出一种VSD-MPC方法用于主动悬架预瞄控制。利用拉盖尔函数将传统MPC中二次规划求解最优控制序列的过程替代为拟合求导环节,降低算力需求。仿真测试结果表明,本文设计的主动悬架预瞄控制策略不仅能够在不同的车速下使车辆的垂向性能至少提升39.4%,同时可以将算力降低50%以上。 展开更多
关键词 车辆工程 主动悬架 预瞄控制 车速自适应 模型预测控制
在线阅读 下载PDF
基于改进自抗扰控制的艾草收获滚筒转速稳定控制研究
13
作者 李奕 张开 +1 位作者 陈俊男 胡新宇 《液压与气动》 北大核心 2026年第1期73-85,共13页
为解决艾草收获机弹齿滚筒在作业过程中因负载扰动引起的转速不稳定问题,提出了一种基于改进自抗扰控制的滚筒转速稳定控制策略。建立了滚筒负载数学模型,分析了负载扰动对液压系统动态特性的影响规律。为提高比例阀在复杂工况下的响应... 为解决艾草收获机弹齿滚筒在作业过程中因负载扰动引起的转速不稳定问题,提出了一种基于改进自抗扰控制的滚筒转速稳定控制策略。建立了滚筒负载数学模型,分析了负载扰动对液压系统动态特性的影响规律。为提高比例阀在复杂工况下的响应平滑性与抗扰能力,在传统自抗扰控制算法的扩张状态观测器中引入平滑非线性函数shfal,改善了原fal函数在原点处的不光滑性,实现了对扰动的连续估计与补偿。通过AMESim-MATLAB联合仿真验证,改进自抗扰控制策略,在稳态、正弦及突变负载条件下均具有较快的响应速度、更高的稳态精度和更强的抗扰性能。田间试验进一步表明,该控制策略能够显著改善脱叶效果,提高脱净率,降低含杂率与破损率,验证了其在实际作业条件下的工程可用性。研究表明,该方法能有效抑制滚筒转速波动,提升系统稳定性与作业质量,为艾草收获机液压控制系统的优化设计提供了可行方案与理论依据。 展开更多
关键词 艾草收获 转速控制 液压系统 自抗扰控制
在线阅读 下载PDF
一种新型管道内检测器泄流调速装置的数值模拟分析
14
作者 唐建 余文秀 +2 位作者 张秋平 焦向东 丁学鹏 《上海交通大学学报》 北大核心 2026年第2期319-330,共12页
针对输油管道内检测器运行速度控制问题,提出了一种新型的泄流调速装置,该装置由泄流阀座、泄流阀芯、弹簧、导杆等组成.通过分析检测器泄流调速装置在水平管道内的受力情况,建立了泄流调速装置的数学模型.利用数值模拟的方法研究了泄... 针对输油管道内检测器运行速度控制问题,提出了一种新型的泄流调速装置,该装置由泄流阀座、泄流阀芯、弹簧、导杆等组成.通过分析检测器泄流调速装置在水平管道内的受力情况,建立了泄流调速装置的数学模型.利用数值模拟的方法研究了泄流阀座弧度、泄流阀芯-检测器后端距离以及入口流体速度对管道内检测器运动状态的影响.研究结果表明,在相同边界条件下,流体介质通过检测器时,泄流调速装置前后两端压差、总水头损失系数、流场的湍流动能值与泄流阀座左侧弧度成反比关系,而与右侧弧度成正比关系,当泄流阀座左侧弧度为60°、右侧弧度为15°时,各参数均为最小值;入口流体速度的增加会导致泄流调速装置前后两端压差、流场湍流动能值增大,当泄流阀座弧度相同、入口流体速度从0.6 m/s增加到2 m/s时,压差增加了106290 Pa,湍流动能增加了1.831 m^(2)/s 2;泄流阀芯-检测器后端距离与泄流调速装置前后两端压差、检测器速度成反比关系,当阀芯-检测器后端距离从15 mm增加到35 mm时,泄流调速装置前后两端的压差减小了240 Pa.本研究为优化输油管道内检测器的运行性能、提高检测效率提供了重要的理论基础与实践指导. 展开更多
关键词 输油管道 内检测器 泄流调速装置 压差 速度控制
在线阅读 下载PDF
涡流发生器对动车组气动减阻的研究
15
作者 崔洪江 吴博威 +1 位作者 樊伟航 关颖 《铁道学报》 北大核心 2026年第2期31-39,共9页
为了降低列车高速运行受到的气动阻力,选择尾车3个典型安装位置,包括流线型过渡位置、边界层突变处和尾车压力突变处。采用基于SST k-ω湍流模型的雷诺时均法研究高速列车尾车安装涡流发生器对尾部流动特征以及列车气动载荷的影响。结... 为了降低列车高速运行受到的气动阻力,选择尾车3个典型安装位置,包括流线型过渡位置、边界层突变处和尾车压力突变处。采用基于SST k-ω湍流模型的雷诺时均法研究高速列车尾车安装涡流发生器对尾部流动特征以及列车气动载荷的影响。结果表明:涡流发生器能显著改变尾车周围的流场,产生一对与原涡流旋向相反的涡流结构,降低尾流涡强度和范围。在尾车安装涡流发生器后,气流流动受到涡流发生器的阻碍产生积聚,从而在尾车表面形成正压区域,降低压差阻力;当涡流发生器布置在尾车压力突变处时,阻力显著降低,尾车阻力降低16.8%,整车阻力降低6.82%。研究结果为动车组气动减阻提供了新的思路,对突破传统气动减阻技术的局限性具有重要意义。 展开更多
关键词 动车组 流动控制 涡流发生器 气动减阻 压差阻力
在线阅读 下载PDF
高速平面机械臂柔性末端残余振动主动控制方法
16
作者 李华 蒋勉 +2 位作者 谢凌波 何宽芳 徐震 《噪声与振动控制》 北大核心 2026年第1期68-75,共8页
高速运行的机械臂会对其机械结构产生强烈冲击,尤其加速度与减速度的突变导致在其柔性末端产生较大的残余振动,从而影响机械臂的运动和定位精度。为有效抑制平面机械臂柔性末端残余振动,避免控制系统高度依赖机械臂精确模态参数,主要研... 高速运行的机械臂会对其机械结构产生强烈冲击,尤其加速度与减速度的突变导致在其柔性末端产生较大的残余振动,从而影响机械臂的运动和定位精度。为有效抑制平面机械臂柔性末端残余振动,避免控制系统高度依赖机械臂精确模态参数,主要研究高速平面机械臂柔性末端残余振动主动控制方法。首先对平面机械臂进行有限元分析获取振型和频率,其次建立平面机械臂运动学模型并对运动轨迹进行开环平滑速度规划,最后以加速度为反馈信号实现闭环残余振动控制。考虑由滤波、加速度-位移相位差及传输等因素引起的残余振动加速度信号相位滞后,进一步采用相移技术,通过加速度相移补偿和模糊反馈控制,进行残余振动控制研究与实验验证。实验结果表明,开环速度规划算法使速度具有良好的平滑性,对残余振动有一定抑制能力;闭环加速度反馈控制算法采用合适超前时间和模糊反馈增益,能达到更好的高速机械臂残余振动控制效果。 展开更多
关键词 振动与波 高速平面机械臂 残余振动 速度规划 加速度反馈 模糊反馈控制
在线阅读 下载PDF
一种电子增材制造喷墨打印精度的协同控制方法
17
作者 刘清涛 于攀宇 +3 位作者 郭炯棋 尹恩怀 杨鹏涛 吕景祥 《华南理工大学学报(自然科学版)》 北大核心 2026年第1期94-103,共10页
电子增材制造技术在高精度微电子制造中具有重要的应用价值,但打印速度波动导致的墨滴落点低精度问题一直制约着打印质量的提升。鉴于此,该文提出了基于LinuxCNC的S型速度规划+恒间距喷射(SSP-FDI)协同控制策略,通过将传统数控系统速度... 电子增材制造技术在高精度微电子制造中具有重要的应用价值,但打印速度波动导致的墨滴落点低精度问题一直制约着打印质量的提升。鉴于此,该文提出了基于LinuxCNC的S型速度规划+恒间距喷射(SSP-FDI)协同控制策略,通过将传统数控系统速度算法优化为S型速度控制算法来有效降低运动冲击,采用恒间距触发模式来实现墨滴间距的精确控制,削弱速度波动对落点精度的影响。作者还自主搭建了一套集成五轴运动控制与电子喷墨打印的实验平台,开发了相应的控制系统,设计了多角度折线以及电极对比实验。结果表明:相较于传统的梯形速度规划+固定频率喷射控制策略,SSP-FDI协同控制策略可显著降低墨滴落点的精度误差;在基板温度为100°C、20 mm×20 mm的矩形电极打印实验中,补偿后的电极表面最大粗糙度降低至6μm;在5组不同的基板温度下,样件表面粗糙度平均降幅达18.79%,电阻率平均降幅达18.70%。该文提出的基于LinuxCNC的协同控制策略能有效提升复杂轨迹下的打印质量,为高精度电子器件增材制造提供了一种新的解决方案。 展开更多
关键词 电子增材制造 打印精度 LinuxCNC系统 速度控制算法 协同控制
在线阅读 下载PDF
高速动车组C/C-SiC复合材料制动盘渐进损伤分析
18
作者 王文静 曾祥莉 +2 位作者 韩子轩 曲俊生 焦标强 《中国铁道科学》 北大核心 2026年第1期12-23,共12页
为进一步研究碳陶制动盘在高速服役工况下因热-机耦合载荷产生的损伤,以高速动车组轮装C/C-SiC复合材料制动盘为研究对象,在开展碳陶复合材料力学性能试验的基础上,建立碳陶制动盘热-机耦合仿真模型并进行试验验证,仿真研究不同制动工... 为进一步研究碳陶制动盘在高速服役工况下因热-机耦合载荷产生的损伤,以高速动车组轮装C/C-SiC复合材料制动盘为研究对象,在开展碳陶复合材料力学性能试验的基础上,建立碳陶制动盘热-机耦合仿真模型并进行试验验证,仿真研究不同制动工况下制动盘的热-机特性演化规律;结合Linde准则和Hashin准则,计算高速紧急制动工况下制动盘易损伤区域的损伤量并探究纤维排布方向对制动盘损伤的影响。结果表明:碳陶复合材料面内的拉伸强度约为层间的7.3倍,面内的剪切强度约为层间的2.0倍,碳陶复合材料面内的拉伸和剪切性能优于层间,面内的高强度和高模量可保障抗变形能力,层间压缩性能稳定能避免承压工况下的分层失效,为其作为制动盘材料的适用性提供了力学支撑;热-机耦合仿真表明,随着制动初速度和制动压力的增大,碳陶制动盘的温度场、应力场及变形量均呈单调递增趋势,最大应力集中于螺栓沉孔区域,且400 km·h^(-1)初速度紧急制动工况下的渐进损伤计算结果也进一步证实制动盘最大损伤同样聚集于螺栓沉孔处;纤维方向和结构夹角的变化对制动盘轴向损伤变量影响较小,其峰值波动范围为0.153~0.157。 展开更多
关键词 高速动车组 碳陶复合材料 轮装制动盘 热-机耦合仿真 渐进损伤分析 Linde准则 Hashin准则
在线阅读 下载PDF
考虑抑制二次跌落的风电自适应频率支撑控制策略及其参数整定
19
作者 张超 文云峰 +2 位作者 黎婧娴 廖帮昆 孙铭锐 《电工技术学报》 北大核心 2026年第5期1510-1525,共16页
风资源的起伏致使风电在不同场景下对系统的频率支撑能力有所差异,而风电的频率支撑能力、控制策略及控制参数的不匹配将严重影响系统频率的动态响应。为提升风电参与频率支撑时的稳定性与持续性,该文首先提出一种考虑转速平滑恢复的风... 风资源的起伏致使风电在不同场景下对系统的频率支撑能力有所差异,而风电的频率支撑能力、控制策略及控制参数的不匹配将严重影响系统频率的动态响应。为提升风电参与频率支撑时的稳定性与持续性,该文首先提出一种考虑转速平滑恢复的风机频率支撑控制策略,使风机在系统频率到达最低点之后自适应地减小有功功率输出,使其进入转速恢复状态,同时根据转速恢复情况自适应地减小频率支撑控制参数,抑制了转速恢复对系统频率的不利影响;其次,依据风机参与频率支撑期间的运行点偏移,求得不同转速下风机的最小动能损耗,进而求出风机的最大频率支撑能量;然后推导出了计及同步机与风电参与频率支撑的系统频率动态响应模型的时域表达式,统一了不同阻尼比下的频率极值点计算式;随后,基于系统频率安全约束与风机频率支撑能量约束,建立了分别以风机频率支撑量和风机偏移量最小为目标的优化模型,实现了故障场景下各风电场控制参数的整定;最后通过IEEE 30节点系统和实际电网的仿真算例验证了所提方法的有效性。 展开更多
关键词 风电场 频率支撑控制 参数整定 转速恢复 二次跌落
在线阅读 下载PDF
泵阀联控锚杆钻机回转马达转速研究
20
作者 高有山 唐光伟 +2 位作者 闫政 张梦圆 孙浩然 《机床与液压》 北大核心 2026年第1期119-126,共8页
针对锚杆钻机在复杂煤巷钻锚支护作业中,因围岩性状多变导致马达转速调节不及时而引起的钻头磨损与卡钻问题,提出一种泵阀联合控制策略,并构建泵阀联合控制系统。在阀控部分,针对回转系统的非线性和未建模扰动,设计改进型滑模自抗扰控制... 针对锚杆钻机在复杂煤巷钻锚支护作业中,因围岩性状多变导致马达转速调节不及时而引起的钻头磨损与卡钻问题,提出一种泵阀联合控制策略,并构建泵阀联合控制系统。在阀控部分,针对回转系统的非线性和未建模扰动,设计改进型滑模自抗扰控制器(SM-ADRC),利用扩张状态观测器估计并补偿系统总扰动,结合改进的趋近律滑模控制提高响应性和鲁棒性。在泵控部分,伺服电动机转速环采用一阶线性自抗扰控制(LADRC)以提升启动快速性和抗扰能力。为实现动力源与负载的流量匹配,引入基于灰色预测的负载流量预测模型,动态调节伺服电动机转速。此外,在系统中增设蓄能器以补偿负载突变时的流量需求。通过AMESim与Simulink搭建联合仿真模型,并在两种典型工况(围岩硬度系数突变、瞬时负载扰动)下与PID控制策略进行对比验证。结果表明:基于负载流量预测的泵控系统能使绝大部分输出流量用于负载马达回转,稳压阀溢流仅占5.82%,实现了流量的高效利用;在阀控部分,改进型SM-ADRC在围岩硬度系数由f=4突变至f=8时,马达转速超调量小于PID控制,调整时间略长但综合控制性能更优;在f=6工况下施加18 N·m瞬时扰动时,SM-ADRC控制的马达转速波动更小,稳定时间较PID控制缩短6.4%;在泵控部分,LADRC相较于PID控制使电动机转速响应时间减少10.6%,超调量降低1.8%;蓄能器有效平抑了系统压力和流量冲击,并在负载突变时快速补充流量,提升了系统动态响应能力。 展开更多
关键词 泵阀联控 改进型滑模自抗扰控制 马达回转速度 锚杆钻机
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部