Thermal Model of High-Speed Spindle Units

For the purpose to facilitate development of high-speed Spindle Units (SUs) running on rolling bearings, we have developed a beam element model, algorithms, and software for computer analysis of thermal characteristics of SUs. The thermal model incorporates a model of heat generation in rolling bearings, a model of heat transfer from bearings, and models for estimation of temperature and temperature deformations of SU elements. We have carried out experimental test and made quantitative evaluation of the effect of operation conditions on friction and thermal characteristics of the SUs of grinding and turning machines of typical structures. It is found that the operation conditions make stronger effect on SU temperatures when rpm increases. A comparison between the results of analysis and experiment proves their good mutual correspondence and allows us to recommend application of the models and software developed for design and research of high-speed SUs running on rolling bearings.

Nonlinear Mathematical Modeling and Sensitivity Analysis of Hydraulic Drive Unit

The previous sensitivity analysis researches are not accurate enough and also have the limited reference value, because those mathematical models are relatively simple and the change of the load and the initial displacement changes of the piston are ignored, even experiment verification is not conducted. Therefore, in view of deficiencies above, a nonlinear mathematical model is established in this paper, including dynamic characteristics of servo valve, nonlinear characteristics of pressure-flow, initial displacement of servo cylinder piston and friction nonlinearity. The transfer function block diagram is built for the hydraulic drive unit closed loop position control, as well as the state equations. Through deriving the time-varying coefficient items matrix and time-varying free items matrix of sensitivity equations respectively, the expression of sensitivity equations based on the nonlinear mathematical model are obtained. According to structure parameters of hydraulic drive unit, working parameters, fluid transmission characteristics and measured friction-velocity curves, the simulation analysis of hydraulic drive unit is completed on the MATLAB/Simulink simulation platform with the displacement step 2 mm, 5 mm and 10 mm, respectively. The simulation results indicate that the developed nonlinear mathematical model is sufficient by comparing the characteristic curves of experimental step response and simulation step response under different constant load. Then, the sensitivity function time-history curves of seventeen parameters are obtained, basing on each state vector time-history curve of step response characteristic. The maximum value of displacement variation percentage and the sum of displacement variation absolute values in the sampling time are both taken as sensitivity indexes. The sensitivity indexes values above are calculated and shown visually in histograms under different working conditions, and change rules are analyzed. Then the sensitivity indexes values of four measurable parameters, such as supply pressure, proportional gain, initial position of servo cylinder piston and load force, are verified experimentally on test platform of hydraulic drive unit, and the experimental research shows that the sensitivity analysis results obtained through simulation are approximate to the test results. This research indicates each parameter sensitivity characteristics of hydraulic drive unit, the performance-affected main parameters and secondary parameters are got under different working conditions, which will provide the theoretical foundation for the control compensation and structure optimization of hydraulic drive unit.

Force Control Compensation Method with Variable Load Stiffness and Damping of the Hydraulic Drive Unit Force Control System

Each joint of hydraulic drive quadruped robot is driven by the hydraulic drive unit（HDU）, and the contacting between the robot foot end and the ground is complex and variable, which increases the difficulty of force control inevitably. In the recent years, although many scholars researched some control methods such as disturbance rejection control, parameter self-adaptive control, impedance control and so on, to improve the force control performance of HDU, the robustness of the force control still needs improving. Therefore, how to simulate the complex and variable load characteristics of the environment structure and how to ensure HDU having excellent force control performance with the complex and variable load characteristics are key issues to be solved in this paper. The force control system mathematic model of HDU is established by the mechanism modeling method, and the theoretical models of a novel force control compensation method and a load characteristics simulation method under different environment structures are derived, considering the dynamic characteristics of the load stiffness and the load damping under different environment structures. Then, simulation effects of the variable load stiffness and load damping under the step and sinusoidal load force are analyzed experimentally on the HDU force control performance test platform, which provides the foundation for the force control compensation experiment research. In addition, the optimized PID control parameters are designed to make the HDU have better force control performance with suitable load stiffness and load damping, under which the force control compensation method is introduced, and the robustness of the force control system with several constant load characteristics and the variable load characteristics respectively are comparatively analyzed by experiment. The research results indicate that if the load characteristics are known, the force control compensation method presented in this paper has positive compensation effects on the load characteristics variation, i.e., this method decreases the effects of the load characteristics variation on the force control performance and enhances the force control system robustness with the constant PID parameters, thereby, the online PID parameters tuning control method which is complex needs not be adopted. All the above research provides theoretical and experimental foundation for the force control method of the quadruped robot joints with high robustness.

Controller design based on viscoelasticity dynamics model and experiment for flexible drive unit

In order to ensure that the system has the advantage of light weight and vibration absorption, the steel rope is used as a flexible transmission part. A flexible drive unit(FDU) is developed, whose features are guided by steel rope, increasing force by the movable pulley group, modular, convenient and flexible. Dynamics model for controller is deduced based on the constitutive equation of viscoelasticity. Controller is designed for position control and is based on the viscoelasticity dynamics model compensation control strategy proposed. The control system is based on the TURBO PMAC multi-axis motion control card.Prototype loading experiments and velocity experiments results show that the FDU can reach 2 Hz with no load and the max speed of 30(°)/s. The FDU has the capability of the load torque 11.2 N·m and the speed of 24(°)/s simultaneously, and the frequency response is 1.3 Hz. The FDU can be used to be the pitch joint of hip for biped robot whose walking speed is 0.144 km/h theoretically.

Model of Rotation Accuracy of High-Speed Spindles on Ball Bearings

For the purpose to improve a design quality of high-speed spindle units, we have developed mathematical models and software to simulate a rotation accuracy of spindles running on ball bearings. In order to better understand the mechanics of ball bearings, the dynamic interaction of ball bearings and spindle unit, and the influence of the bearing imperfections on the spindle rotation accuracy, we have carried out computer aided analysis and experimental studies. When doing this, we have found that the spindle rotation accuracy can vary drastically with rotational speed. The influence of bearing preload has a secondary importance. Comparison of the results of these studies has demonstrated adequacy of the models developed to the real spindle units.

Analysis of stress and natural frequencies of high-speed spatial parallel mechanism

In order to grasp the dynamic behaviors of 4-UPS-UPU high-speed spatial parallel mechanism, the stress of driving limbs and natural frequencies of parallel mechanism were investigated. Based on flexible multi-body dynamics theory, the dynamics model of 4-UPS-UPU high-speed spatial parallel mechanism without considering geometric nonlinearity was derived. The stress of driving limbs and natural frequencies of 4-UPS-UPU parallel mechanism with specific parameters were analyzed. The relationship between the basic parameters of parallel mechanism and its dynamic behaviors, such as stress of driving limbs and natural frequencies of parallel mechanism, were discussed. The numerical simulation results show that the stress and natural frequencies are relatively sensitive to the section parameters of driving limbs, the characteristic parameters of material on driving limbs, and the mass of moving platform. The researches can provide important theoretical base of the analysis of dynamic behaviors and optimal design for high-speed spatial parallel mechanism.

Repacking practice for G-3 engineering driller power unit with drive shaft of dual channel reverse circulation

In order to satisfy operating requirements for constant core drilling technology in reverse circulation with hollow-through DTH,the power unit of G-3 engineering driller was ameliorated. The new one with dual channel drive shaft, achieved the perfect assemble with transmission structure of the original power unit. It could interconvert according to need by using two sets of drive shafts with direct and reverse circulation. The repacked G-3 engineering driller carried on experiment in the field test in Luanchuan molybdenum mine of Henan, whose effect was very good.

鲸鱼算法优化CNN-BiGRU-ATTENTION的车辆换道意图识别模型

针对时空多样特征、超参数敏感性影响车辆行为意图识别精度的问题,提出一种改进的CNN-BiGRU-ATTENTION混合换道意图识别模型。采用目标车辆轨迹序列和与周围车辆互动特征作为模型输入进行训练,实现考虑车辆动态变化状态的意图识别预测;使用鲸鱼优化算法对模型调整参数进行多目标寻优,降低模型调优难度;利用NGSIM数据集对模型进行评估校验。结果表明:所提出的WOA-CNN-BiGRU-ATTENTION模型与CNN-BiGRU-ATTENTION模型、Transformer模型相比,准确率分别提升了4.53%、0.97%,达到97.64%;WOA-CNN-BiGRU-ATTENTION模型在不同预判时间下的意图识别准确率最高,在换道前2.5 s的识别精度均能达到91%以上,证明模型具有较强的车辆换道意图识别性能。

面向三维多目标追踪的运动补偿优化方法

三维多目标追踪是自动驾驶系统中的关键模块之一,其结果的优劣主要取决于追踪模块中数据关联过程的准确度.现有的追踪方法大多从外观特征或运动特征出发计算两帧之间物体的相似度,而基于运动特征的方法通常根据当前帧和历史帧三维包围框之间的交并比(Intersection over Union,IoU)进行关联,然而这种方式在观测点物体自身运动时存在严重缺陷.在观测点物体自身进行运动时,观测到的两帧数据将处于不同的局部坐标系,导致无法使用运动模型准确预测已追踪物体在下一帧中的位置.本文针对上述问题,通过引入观测点自身的惯性测量单元(Inertial Measurement Unit,IMU)或全球定位系统(Global Positioning System,GPS)数据,在一帧数据到达之后计算当前帧局部坐标系与上一帧局部坐标系之间的旋转和平移关系,并对已追踪的物体状态按得到的坐标变换关系进行运动补偿,使其抵消因观测点自身运动造成的偏移量.这种运动补偿增强了追踪模块的数据关联环节,提高追踪时三维包围框的关联成功率,降低误关联数量,改善三维多目标追踪的精度.在相关追踪框架及KITTI数据集上的原型验证表明,所提的运动补偿优化方法实现了1%左右的精度提升.

机载130 mJ激光照射器的脉冲驱动电源设计

针对机载130 mJ激光照射器对脉冲驱动电源的实际使用需求,设计了一款高可靠性、宽温度范围、小型化的脉冲驱动电源。采用了基于超低ESR储能单元的前级低功率充电、后级高功率脉冲放电的技术方案。详细设计中,防反及缓启电路采用双PMOS管的方式;BOOST升压式充电电路选用具有开关频率可调、逐周期电流限制的控制芯片CYT5022JVS;储能单元由多只超低ESR的高分子固态铝电解电容器并联构成;放电电路开关管选用两只2.3 mΩ导通内阻的IRF150P220并联来降低发热功率。为保证宽温工作范围,采用电压补偿的方式来解决高、低温下储能单元容值变化的问题。测试表明,驱动电源能够输出峰值160 A、脉宽230μs、频率25 Hz的脉冲电流,激光照射器在照射模式下单脉冲平均能量大于130 mJ,满足系统要求。

智能网联环境下车载终端的发展现状与挑战

随着智能网联技术的快速发展,智能网联汽车装配的智能车载终端功能也相应扩展。经过数十年的进步,智能车载终端系统在多个领域取得了显著的发展,并在自动驾驶领域展现出巨大的潜力。该文从智能车载终端在智能网联环境中的现状入手,描述了智能车载终端系统的架构,并回顾了在车间通信和车路协同赋能下车载终端系统的发展历程;对5G时代车联网无线通信技术的创新对智能车载终端发展的重大影响做了深入分析,并详细回顾了在协同驾驶与控制、边缘计算与雾计算、数字孪生等领域的最新研究成果,同时指出了智能车载终端在信息安全和自动驾驶测试领域面临的挑战。

基于IMU与激光雷达融合的无人弹药补给车SLAM系统研究

针对单一传感器建图精度低、实时性不足的问题,将IMU融合到激光雷达SLAM算法中。首先,采用手眼标定方法对2种传感器坐标系外参进行标定,实现传感器在时间与空间上的对齐。然后,结合因子图优化模型,解决在建图过程中产生的漂移现象,并将IMU融合到激光雷达LeGO-LOAM算法中。最后,在室外场景下搭建了无人弹药补给车SLAM实验平台,分别进行了LeGO-LOAM算法融合IMU前后的建图和定位试验。结果表明,融合IMU后的SLAM算法建图和定位精度都明显提高,满足了在未知环境下无人弹药补给车建图和定位的性能要求。

LF精炼炉钢包回转台驱动系统设计与分析

LF炉是整个钢铁精炼工艺过程中最为重要的设备,具有脱硫、脱氧,微调钢水成分的作用,对提高钢水品质具有重要作用;是每个钢企生产优钢特钢的必备设备。现有LF精炼炉主要结构型式分为双车式、回转台式以及电极旋转式。回转台式LF炉其特点是利用回转台的自转将钢水从等待工位转运钢水至冶炼工位进行冶炼;回转台式LF炉具有占地面积小,使用安全可靠,维护保养工作量小,效率高等优势。回转台作为LF精炼炉的重要组成设备,对整个精炼炉安全运行有着重要的作用;而回转台的平稳运行又取决于驱动装置设计的可靠性。针对回转台的驱动装置设计进行分析。通过对回转台驱动系统基础数据的计算、电机和减速机的选型,提出一个安全、可靠的设计方案,以便其他设计者进行参考。

城市道路场景下考虑多类交通参与者的多模态车辆轨迹预测方法研究

车辆轨迹预测是自动驾驶的关键技术之一,针对以往模型较少考虑城市道路场景中车辆以外多类交通参与者的问题,本研究提出了一种多类交通参与者的多模态车辆轨迹预测模型。该模型使用门控循环单元对历史轨迹信息进行编码,并利用注意力机制将多类交通参与者的特征映射到用图结构表达的驾驶场景中,通过图注意力网络进行环境特征提取,从而使模型能感知环境中的多类交通参与者。此外,模型通过节点轨迹预测与坐标轨迹预测模块输出最终的多模态轨迹预测结果。基于城市道路场景数据集nuScenes的实验结果表明:相较于同类现有模型,所提出的模型算力需求更低、预测更准确,且能适用于人车混合的城市道路驾驶场景。

矿井中单轨吊辅助运输系统驱动单元配置与实践研究

单轨吊作为矿井中人员、材料、设备的辅助运输设备,其具有安全可靠、爬坡能力强、不跑车掉道、不受底板影响等优势,使得单轨吊在煤矿辅助运输系统中有着较为广阔的应用前景。但我国对于单轨吊的研究时间较短,并且未根据矿井实际地质条件和巷道条件进行具体设计选择,难以保障单轨吊设计的应用价值。据此,以某煤矿为研究案例,结合煤矿地质和巷道条件,合理实施巷道断面锚固、单轨吊选择及吊箱以及单轨吊作业流程优化设计。通过SolidWorks+ANSYS联合仿真方式,确认优化后机架、夹紧装置等单轨吊辅助运输系统驱动单元关键结构件的受力情况,进而快速分析优化设计可行性。另外,将优化配置应用工程实践,确认单轨吊辅助运输系统驱动单元配置设计具有较强的社会效益和经济效益。

Biomimetic Lightweight Design of Legged Robot Hydraulic Drive Unit Shell Inspired by Geometric Shape of Fish Bone Rib Structure

The lightweight design of hydraulic quadruped robots,especially the lightweight design of the leg joint Hydraulic Drive Unit(HDU),can improve the robot's response speed,motion speed,endurance,and load capacity.However,the lightweight design of HDU is a huge challenge due to the need for structural strength.This paper is inspired by the geometric shape of fish bones and biomimetic reinforcing ribs on the surface of the HDU shell are designed to increase its strength and reduce its weight.First,a HDU shell with biomimetic fish bone reinforcing ribs structure is proposed.Then,the MATLAB toolbox and ANSYS finite element analysis module are used to optimize the parameters of the biomimetic reinforcing ribs structure and the overall layout of the shell.Finally,the HDU shell is manufactured using additive manufacturing technology,and a performance testing platform is built to conduct dynamic and static performance tests on the designed HDU.The experimental results show that the HDU with biomimetic fish bone reinforcing ribs has excellent dynamic performance and better static performance than the prototype model,and the weight of the shell is reduced by 20%compared to the prototype model.This work has broad application prospects in the lightweight and high-strength design of closed-pressure vessel components.

空冷机组汽轮机主轴直接驱动给水泵的变工况运行仿真试验

汽轮机主轴直接驱动给水泵技术是一种全新的给水泵驱动方式,目前国内尚无成熟的运行经验。针对采用该技术的某350 MW直接空冷机组进行了系列变工况运行仿真试验。结果表明:对于配置1台100%容量主机泵和1台50%容量备用泵的机组,该技术完全能够满足在机组背压快速变化、负荷变化及给水泵故障等工况下给水流量的需求。

自动驾驶多目标追踪运动IMU局部信息补偿优化

多目标追踪是自动驾驶系统中的关键模块之一,其结果的优劣主要取决于追踪模块中数据关联过程的准确度。通过引入观测点自身的惯性测量单元(IMU)或全球定位系统(GPS)数据,在一帧数据到达之后计算当前帧局部坐标系与上一帧局部坐标系之间的旋转和平移关系,并对已追踪的物体状态按得到的坐标变换关系进行运动补偿,使其抵消因观测点自身运动造成的偏移量;这种运动补偿增强了追踪模块的数据关联环节,提高追踪时三维包围框的关联成功率,降低误关联数量,改善多目标追踪的精度;在相关追踪框架及KITTI数据集上的原型验证表明,所提的运动补偿优化方法实现了1%左右的精度提升。

光伏与网电协同接入变频器驱动抽油机技术

近年来采油厂利用井场空间安装了一些光伏发电系统,采用光伏发电接入电网模式,采油厂两千多口抽油机井从网电上获取电能,这个模式电能在转换和传输过程中产生损耗。本文研究井场光伏就地消纳技术,根据采油厂有大量抽油机井使用变频器的情况,开展了光伏直接接入抽油机井变频器的直流线路技术研究,基于抽油机井负载和光伏发电规律,建立稳定的光伏-网电协同驱动接入电路,并采用超级电容吸收和回馈抽油机井的倒发电。进行了抽油机井试验,验证了技术性能,还减少了光伏转换和传输过程的损耗,有利于光伏电能就地使用。

并网光伏发电机组中旋转机械驱动控制方法研究

并网光伏发电机组为了最大限度吸收太阳能,需要在面板底部安装旋转机械装置,以便可以随时调整方向,保证发电效率,该文研究了一种有效的并网光伏发电机组旋转机械驱动控制方法。计算并网光伏发电机组暂态响应和旋转机械动不平衡量,获取旋转机械的运行状态。将虚拟同步发电机控制策略、PI调节器和本体算法等自动化控制技术结合在一起,建立旋转机械驱动控制模型,控制并网光伏发电机组输出功率达到初始振荡幅值,实现对旋转机械的驱动控制。实验结果表明,该方法的振动幅度未超过0.6 cm,平均控制响应时间为1.28 s,失控率未超过7.5%,具有良好的驱动控制能力。