共查询到20条相似文献,搜索用时 281 毫秒
1.
2.
为了解决自来水厂原水水质突变引起的应变滞后问题,使预测信息更加准确、及时、全面的服务于水厂作业人员,该文应用时间序列的ARMA模型对原水水质的浊度进行分析研究,建立水质变化的回归模型,并在此模型基础上进行预测验证。仿真结果表明,该模型能够较好地拟合水质变化曲线,具有较高的精确度,能够对实际生产起良好的指导作用。 相似文献
3.
工业搬运车作为生产工具,设计工业搬运车必定要考虑提高生产效率和保障作业人员的安全性与舒适性,工业搬运车在搬运货物时,安全因素是主要考虑和保证的,安全的工作环境是保障工作效率的前提。在工业搬运车作业过程中,安全性影响因素有:驾驶室视野、驾驶室舒适性因素、驾驶座椅设计、操纵杆位置。项目以JACK为主要仿真工具,对工业搬运车虚拟模型仿真分析,并结合人机工程学原理分析驾驶员所处的人-机-环境系统。分析座椅H点和座椅设计、可视域仿真、双手可达域仿真、人体脊椎受力仿真、关节舒适度分析,再对驾驶员作业静态强度进行预测,最后基于人机工程学原理的工业搬运车作业环境分析、设计优化和建议。 相似文献
4.
5.
针对综掘面风筒出风口参数不能随瓦斯、粉尘的浓度变化动态调节风流状态,不能实现复杂恶劣下矿井物理作业环境和虚拟模型互联互通的智能化煤矿发展的要求,提出基于数字孪生技术的综掘面风流智能化调控方法,建立了风流调控装置的动态虚拟模型。研究了风筒出风口参数调控规则获取、基于长短期记忆网络的瓦斯粉尘浓度预测、基于遗传—反向传播神经网络的风筒出风口参数决策等支持虚拟模型实现动态预警预测、具有自主学习和自主决策功能的关键技术。实验表明,数字孪生系统能够高保真度地再现矿井巷道的作业环境,实现虚实融合、迭代优化和以虚控实的综掘面风流新型调控方式,有效优化瓦斯和粉尘的运移分布,提高煤矿开采作业的智能化水平。 相似文献
6.
基于人体血液循环系统的基本生理学知识,确定人工心脏瓣膜脉动流实验系统的工作原理及设计方案。根据人体健康、运动、心衰三种生理状态下各种生理参数的范围,确定人工心脏瓣膜脉动流实验系统的设计要求及参数指标。依据血液循环系统主要组成部分的功能和特征以及流体力学相似性理论,设计脉动流模拟循环系统。将人体血液循环系统类比为流体系统,应用AMESim仿真软件搭建脉动流实验系统的等效流体系统模型,模拟健康、运动、心衰三种生理状态下的血流动力学特性,并将仿真结果与实验系统的关键参数指标,如左心室压力、主动脉压力及脉动血流量进行对比,分析在各种典型参数下得到的仿真结果是否与真实人体生理参数吻合,以此验证人工心脏瓣膜脉动流实验系统设计的合理性。 相似文献
7.
为提高煤矿开采核心设备液压支架推移作业的控制精度,采用模型预测控制算法对支架推移千斤顶进行控制,设计出模型预测控制器,并通过MATLAB搭建仿真平台分析了推移千斤顶实际输出位移对参考序列的追踪情况。仿真分析结果表明:预测时域NP≥15 T时,推移千斤顶位移输出可以对设定参考值进行无超调平稳追踪,并且预测时域越大其位移追踪所需时间越长。研究结果验证了模型预测控制技术应用到液压支架推移作业过程中具备可行性。 相似文献
8.
在核电站中,存在辐照剂量高、结构环境复杂等问题,操作人员作业时不可避免地会受到核辐射照射,对操作人员生命安全带来极大威胁。针对上述问题,研制出作业于核环境下的核电站多功能水下打捞机器人。首先,对机器人进行运动学分析,分别求解出机械手的正逆运动学方程及奇异位形;在此基础上,考虑水阻力、附加质量力以及浮力的影响,建立了机器人的水动力学模型,对机器人复杂水下动力学问题进行描述;最后,根据理论分析研制出该机器人第3代工程样机,并通过核电站现场实验对该机器人进行实验验证。实验结果表明,核电站多功能水下打捞机器人能够快速准确的完成异物抓取作业,实现核环境下的水下异物搜索与异物打捞的设计目标。 相似文献
9.
以斜沟煤矿滚筒式采煤机为研究对象,在分别建立其截割部动力学模型和三维仿真模型的基础上,对不同截齿安装角度和螺旋升角下的动力学特性进行仿真分析。仿真分析认为,MG-260/600-WD型号采煤机适应煤矿生产的相关参数,本次仿真环境可以指导实际生产。 相似文献
10.
11.
The body temperature of pilots wearing anti-G garments becomes uncomfortably or even dangerously high in moderate to hot environments.To reduce the body heat stress,thermal characteristics and thermal protection performance of anti-G garments should be studied systematically,but up to now there is no related research to simulate the anti-G garment thermal protection performance.First,a human thermoregulation model is established which can analyze blood convective heat exchange and the central blood temperature fluctuation,according to this model the heat and mass transfer processes of a thermal system are simulated which consists of human body,an anti-G garment,and the surrounding environment,then on the base of this thermal system simulation influences of clothing permeability,thermal resistance and bladder coverage on anti-G garments are analyzed.Calculation of the human thermoregulation model is carried out by using finite element method.Experiments are conducted in 35 ℃ and 40 ℃ climate chambers,and model built above is well validated by these experiments.Model simulation reveals that low thermal resistance and high permeability of anti-G garments reduce body heat stress in moderate environments.In hot environments,however,anti-G garments with lower thermal resistance increase body heat stress.The body heat stress rises significantly as the bladder coverage area of anti-G garments increases.Anti-G garments thermal parameters can be appropriately designed by using the model built in this paper to ensure body physiological requirements. 相似文献
12.
13.
14.
The existing investigations on thermal comfort mostly focus on the thermal environment conditions, especially of the air-flow field and the temperature distributions in vehicle cabin. Less attention appears to direct to the thermal comfort or thermal sensation of occupants, even to the relationship between thermal conditions and thermal sensation. In this paper, a series of experiments were designed and conducted for understanding the non-uniform conditions and the occupant's thermal responses in vehicle cabin during the heating period. To accurately assess the transient temperature distribution in cabin in common daily condition, the air temperature at a number of positions is measured in a full size vehicle cabin under natural winter environment in South China by using a discrete thermocouples network. The occupant body is divided into nine segments, the skin temperature at each segment and the occupant's local thermal sensation at the head, body, upper limb and lower limb are monitored continuously. The skin temperature is observed by using a discrete thermocouples network, and the local thermal sensation is evaluated by using a seven-point thermal comfort survey questionnaire proposed by American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc(ASHRAE) Standard. The relationship between the skin temperature and the thermal sensation is discussed and regressed by statistics method. The results show that the interior air temperature is highly non-uniform over the vehicle cabin. The locations where the occupants sit have a significant effect on the occupant's thermal responses, including the skin temperature and the thermal sensation. The skin temperaWa-e and thermal sensation are quite different between body segments due to the effect of non-uniform conditions, clothing resistance, and the human thermal regulating system. A quantitative relationship between the thermal sensation and the skin temperature at each body segment of occupant in real life traffic is presented. The investigation result indicates that the skin temperature is a robust index to evaluate the thermal sensation. Applying the skin temperature to designing and controlling parameters of the heating, ventilation and air conditioning(HVAC) system may benefit the thermal comfort and reducing energy consumption. 相似文献
15.
16.
无温度传感器的数控机床进给轴热误差补偿 总被引:1,自引:0,他引:1
分析了目前常见的进给轴热误差补偿方法的缺点,如需要多个温度传感器、模型的鲁棒性较差等。提出一种基于无温度传感器的、强鲁棒性的机床进给轴热误差补偿方法,在恒温环境下实现对运动生热导致的热误差的补偿。给出了热误差模型的推导过程以及应用ISIGHT平台进行参数优化的过程。热误差模型基于摩擦生热、热传导和散热机理实时预测滚珠丝杠的温度场,以实现预测并补偿丝杠热误差的目的。在一台立式加工中心VMC850上对x、y、z轴进行了热误差测试并给出了模型的仿真效果。在另一台立式加工中心VMC850上采用激光干涉仪进行了热误差补偿前后的对比试验和加工对比试验。试验结果表明,该热补偿方法具有很高的精度稳定性和强鲁棒性。 相似文献
17.
为解决煤矿井下低照度、高粉尘、多杂光环境中掘进装备位姿测量不易的问题,提出了一种基于改进随机抽样一致性(RANSAC)特征提取的掘进装备视觉定位方法。首先,对矿用防爆相机采集的三激光标靶图像进行预处理,分别建立形状模型与线框模型;其次,根据形状模型以坐标极值为椭圆模型初始点,将前后两次内点差值比值作为最优迭代次数,迭代求取椭圆模型最优参数获得点特征;然后,根据线框模型以像素坐标模为直线模型初始点,利用自适应条件阈值、抽样次数获得线特征;最后,将点线特征作为三点三线位姿解算模型输入,通过空间坐标变换求得掘进装备位姿信息。实验结果表明,在掘进装备距三激光标靶80 m范围内,所述视觉定位方法的相对误差为±45 mm,可基本满足煤矿井下掘进装备定位需求,为煤矿井下恶劣环境中掘进装备的位姿测量提供一种新的思路。 相似文献
18.
星载光机电设备兼有光学系统和运动机构的特点,前者温度指标要求高,后者构型复杂并且相对星体其他部分运动,这给热设计的验证带来困难。文章以光机电设备激光通信终端为例,提出了热设计的间接验证方法,即通过地面试验数据修正热分析模型、再由热分析模型预示在轨温度,进而验证热设计。设计了热平衡试验,并根据试验结果修正了模型,修正后的试验模型计算结果与试验结果基本一致,81%的测温点偏差小于5℃,模型较好地反映了真实的热物理状态,其预示的在轨温度可用于验证热设计。对比了轨道计算温度与飞行温度,81%的测温点偏差小于4℃,证明了间接验证方法的正确和有效,满足星载激光通信终端的应用要求。所述的验证方法显著降低了热试验的难度,对多姿态与高温度指标的光机电设备具有借鉴意义。 相似文献
19.
针对永磁同步电机设计、参数优化和热分析等问题,对永磁同步电机的热路法温度计算进行了研究,建立了考虑安装和冷却方式的热路模型,提出了一种热路关键参数的测试方法,测试了机壳与空气间的等效热阻、端盖与空气间的等效热阻、安装板与空气间等效热阻,绕组与定子铁芯之间的等效热传导系数,机壳与定子铁芯之间的等效空气隙厚度、端盖与机壳间的等效空气隙厚度、安装板与端盖之间的等效空气隙厚度等热路参数.同时对热路模型进行了热阻敏感性分析,得到了影响电机温升的主要热路参数.实验结果表明,该热路模型和实验测试数据,可以较准确地计算电机温升,误差在5%以内.该热路模型和实验测试热路参数可为同类型电机的设计以及热分析提供很好的参考. 相似文献
20.
Hemodialysis treatment is biased by complications during its operative phases. One of these potential accidents consists in intradialytic hypotension, that causes discomfort to the patient and may even increase the risk of death. Therefore, it is very important to predict these events in routine clinical procedures. A cause of hypotension may be thermal energy/heat exchanges between extracorporeal system and the surrounding environment. A model to evaluate these heat losses is proposed and improved in order to maintain constant patient blood temperature. A convenient procedure is defined to improve and optimize clinical treatment. Although most hemodialysis machines automatically control the dialysate solution temperature starting from peripheral body temperature measurements, the proposed method is based on the control of the pre-dialysis core temperature of the patient, and the temperature of the blood entering the artery from the extracorporeal circuit after the treatment in the dialyzer. Measurements of arterial and venous blood temperatures are obtained in a non invasive way by a suitable estimate of the thermal energy exchanges between the blood and the environment during the extracorporeal recirculation. The suggested model guarantees a constant core temperature of the patient, improving prevention from intradialytic hypotension. 相似文献