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.

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.

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。

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。

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。

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。

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。

外肢体机器人驱动单元低速死区自适应补偿方法

为提高外肢体机器人高功率密度驱动单元的控制精度,提出一种低速死区自适应补偿方法。首先基于最小二乘系统辨识与阻尼辨识方法建立驱动单元模型,然后提出驱动单元的计算力矩控制方法,最后提出驱动单元的低速死区自适应补偿方法,并进行了实验验证。研究结果表明,与传统PID控制方法相比,采用计算力矩控制方法后驱动单元最大角度跟踪误差减小了约53%,平均角度跟踪误差减小了约38%;在计算力矩控制方法的基础上,采用低速死区自适应补偿方法后,驱动单元最大角度跟踪误差减小了约45%,平均角度跟踪误差减小了约60%,驱动单元的控制精度得到了显著提高。

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。

一种自适应路况的重载AGV驱动单元设计与分析

为使重载AGV更好地适应复杂路况,设计一种新型驱动单元并对其受力状态进行分析,为驱动电机的选型提供直接依据;对AGV底盘以及路况做出了分析,利用SolidWorks Simulation静力分析模块对底盘进行强度研究;对样机进行了实际测试,获取数据分析验证驱动单元设计的可行性。

基于新型混合多电平变换器的车载供电系统

采用蓄电池和超级电容的储能单元是车载供电-驱动系统中的重要部分。此处提出了一种新型的混合级联型多电平充放电电路拓扑结构,储能单元的连接方式不再是传统的直接串并联,而是由每个桥臂单独控制储能单元后进行级联。将传统的均压电路和充放电控制电路合并为一个电路。由于每个储能单元是独立控制的,所以能够实时实现电压均衡,既能保护储能单元,也能提高储能单元的利用率。该电路拓扑输出为多电平电压,可以减小逆变器输出的电压变化率对电机绝缘的影响,并且谐波含量少,提高控制性能。分析了电路拓扑控制策略,并以铅酸蓄电池为例进行了实验,实验结果验证了该新型储能系统拓扑的合理性和优越性。

氧化锆陶瓷在高温转速校准装置传动部件的应用浅析

本文针对高温转速校准装置中传动部件的设计进行研究。首先,基于力学理论计算,初步确定材料强度是否适用;其次,利用仿真计算,分析传递精度是否满足要求;最后,通过高速旋转试验,验证设计结果的适用范围。

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。

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。

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。

输送类驱控一体机及其运动控制系统设计

针对传统自动化生产线输送类单元体积大、成本高、安装过程复杂等不足,设计了输送类单元驱控一体机及其运动控制系统。对该驱控一体机的整体架构及关键部件进行了详细设计,设计优化内容主要包括变频器模块、远程IO模块、MCU控制模块等;数据传输架构方面采用可编程逻辑控制器(PLC)作为系统的主服务器,在此架构中,主服务器与驱控一体机通过工业以太网通信协议(Profinet)进行数据交互,从而实现主服务器对驱控一体机的控制命令传达,其控制命令包括系统的启停、调速、正反转等操作。该输送类驱控一体机一方面降低了现场安装配线的时间成本,以满足柔性化产线依据订单变化而快速响应的生产需求;另一方面也降低了自动化产线维保的复杂程度,以实现低成本、高集成的现代工业自动化作业要求。该产品目前已投入实际生产使用,运行结果表明:一体机抗扰度能力在技术规范内性能正常,整机作业稳定,运行状况良好,达到了降成本、缩空间、减人工、集一体、保性能的设计目的。

西门子SIMOVERT MASTERDRIVE传动系统故障及过程分析

西门子SIMOVERT MASTERDRIVE传动系统广泛应用于工业控制领域。以宝钢某机组SIMOVERT MASTERDRIVE传动系统故障为例,介绍了该套传动系统构成、故障现象及故障处理过程,并从主夹送辊负载情况、回馈方式、整流回馈单元合闸方式、晶闸管/接地检测方式等方面对故障原因进行分析,提出了对主夹送辊设置转矩限幅、改进整流回馈单元分合闸回路、屏蔽整流回馈单元晶闸管接地检测方式及加强传动装置的定期检查和维护的解决方案,彻底解决了原有故障并消除其潜在隐患,保证设备稳定运行。

带式输送机可伸缩机尾结构改进技术

针对矿井综掘工作面作业时,必须在巷道内不断地移动皮带输送机,造成了掘进效率受到影响的问题,通过对综掘巷道内可伸缩皮带机的可伸缩机尾结构进行研究,采用逐点计算法和静力学分析方法,得出了在不同工作状态下输送带的张力是不同的,必须通过锁紧装置,使其尾部的重力分力能提供足够的摩擦力来支撑皮带机的张力。因此,对可伸缩式机尾必须进行结构上的改进,在系统中增加液压回路,使其能够在不同位置上进行尾部伸缩长度的锁定,对于提高掘进速度有着良好的作用。