共查询到18条相似文献,搜索用时 234 毫秒
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在采用电子膨胀阀控制的制冷试验装置中,供冷可调系统通常采用模块式并联供冷,存在滞后性、时变性和非线性等特点.本文针对此特点着重设计了环境温度和压冷机组过热度参数自整定模糊PID控制器,并结合环境温度和过热度整体控制电子膨胀阀开度值,实现电子膨胀阀对制冷系统的精准可靠控制.实践结果表明,搭载了该控制策略的制冷系统,对温控室环境温度控制具有很强的鲁棒性能,并且过热度和限载运行压力均在舒适运行范围之内,有效实现对制冷系统的可靠性和精确性的双重控制. 相似文献
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为有效解决机械谐振问题,伺服系统弹性负载的辨识是非常关键的步骤.本文以工业中最常见的双惯量系统作为辨识对象设计闭环辨识方法,使用伪随机二进制序列作为激励并采集电机电流转速信号.在此基础上,使用最小二乘法拟合系统的自回归移动平均模型,并提高模型阶次以保证拟合精度.为抑制采样噪声的影响,提出基于平衡截断的模型降阶方法,根据Hankel奇异值大小判断系统阶次并提取主要模态.最后,通过仿真和实验进行验证,结果表明:相比于传统辨识方法,本文所提出的辨识方法能够有效抑制噪声干扰,具有更高的精度. 相似文献
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针对广义预测控制(GPC)模型中输入输出数据可能存在噪声和系统先验结构信息未知导致的难于辨识问题,提出了一种子空间辨识的广义预测控制算法。该算法采用变遗忘因子的子空间辨识方法,按照预测优化值与参考输出值的误差构造变遗忘因子,调整采集数据权重,进行在线辨识以提高灵敏度和控制效果。实验结果验证了所提出算法的有效性。 相似文献
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针对蒸发器过热度具有大纯时延的特点,提出采用预测控制的方法。根据对象的输入输出数据辨识出蒸发器过热度对象的动态模型,再根据动态矩阵控制(DMC)的预测模型预测出系统未来时刻的输出,从而达到将过热度控制在目标范围内的要求。实验结果表明,采用DMC的控制方法,系统运行稳定,抗干扰性强,与常规PID控制相比,DMC的控制精度高,控制效果更佳。 相似文献
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《机器人》2015,(5)
为了能够利用变刚度关节实现对机器人动态特性的调整,需要对关节的动态刚度进行有效的辨识和控制.本文首先根据机器人变刚度关节的结构特点建立了简化模型,并对其刚度输出特性表达做出假设;然后对模型中的力矩相关参数进行解耦,消除了关节刚度调节参数对力矩的影响,获取与刚度辨识相关的归一化力矩;利用泰勒展开对归一化力矩进行线性化处理,采用卡尔曼滤波器进行了系数优化,并进一步实现了对关节动态刚度的辨识.仿真中该刚度在线辨识方法可以将辨识误差控制在±2%以内,在实现动态刚度辨识的基础上研究了基于前馈的刚度闭环控制方法,通过仿真实验验证了该方法对于机器人关节刚度闭环控制是有效的. 相似文献
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遥感相机中需要对焦面组件进行高精度的制冷控制以保证高质量的成像效果,因此基于模型识别进行焦面高精度制冷控制策略的设计。制冷系统在硬件上设计特定的二级放大机制以获得高精度测温数据,实现数字化增量式PID控制算法优化以获得高精度控温效果。系统采用脉冲管制冷机作为控制对象,结合继电反馈识别方式与高阶模型,使用最小二乘拟合方法获得制冷系统过程模型。模型的建立保证了控制算法参数的准确性与控温的精确度,这与传统的PID调参手段相比,大大降低了时间成本,提升了系统的控温精度。通过实验结果表明,本系统的控温精度为±27mk,受到干扰后在6分钟内回稳,实现了高精度高稳定度的制冷控制。 相似文献
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Vapor compression refrigeration cycle (VCC) system is a high dimensional coupling thermodynamic system for which the controller design is a great challenge. In this paper, a model predictive control based energy efficient control strategy which aims at maximizing the system efficiency is proposed. Firstly, according to the mass and energy conservation law, an analysis on the nonlinear relationship between superheat and cooling load is carried out, which can produce the maximal effect on the system performance. Then a model predictive control (MPC) based controller is developed for tracking the calculated setting curve of superheat degree and pressure difference based on model identified from data which can be obtained from an experimental rig. The proposed control strategy maximizes the coefficient of performance (COP) which depends on operating conditions, in the meantime, it meets the changing demands of cooling capacity. The effectiveness of the control performance is validated on the experimental rig. 相似文献
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为提高制冷系统故障诊断的准确率,提出一种基于改进引力搜索算法(IGSA)优化的最小二乘支持向量机(LSSVM)的制冷系统故障诊断方法。首先,引入粒子群算法的速度更新机制对引力搜索算法进行改进,增加粒子的记忆性和信息共享能力,提高了算法的收敛速度和搜索精度;其次,利用IGSA对LSSVM的核参数与正则化参数进行优化,得到最优的IGSA-LSSVM故障诊断模型。最后,利用故障模拟实验台模拟制冷系统的四种典型故障,将优化好的LSSVM模型对其进行分类识别,并与标准LSSVM、GSA-LSSVM和PSO-LSSVM模型进行比较。仿真结果表明,基于IGSA优化的LSSVM方法具有良好的辨识能力和泛化能力,能够更好地对制冷系统故障进行诊断。 相似文献
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Bin Li Richard Otten Vikas Chandan William F. Mohs Jeff Berge Andrew G. Alleyne 《Control Engineering Practice》2010,18(12):1406-1417
This paper presents a hysteretic on–off control scheme with optimization algorithms for temperature regulation in refrigerated transport systems. A nonlinear dynamic refrigerated transport system model, which consists of a refrigeration unit and a cargo space, is developed. The model serves as an analytical tool for control design. An optimal on–off control strategy is developed based on the time domain analysis of the temperature oscillations. A cost function involving temperature variations from the set-point, energy consumption and average compressor on–off cycling frequency is introduced for minimization. Choices of weighting values in the cost function give the flexibility of the control approach to meet different requirements. Simulation examples are presented that demonstrate the ability and robustness of the proposed method in achieving tighter temperature regulation and higher system efficiency control in transport refrigeration systems. The simulations are augmented by experimental validation via a novel hardware-in-the-loop load emulation approach. 相似文献
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传统的锅炉过热蒸汽温度控制系统通过检测过热蒸汽温度及其变化趋势来调节减温水量,从而维持过热蒸汽温度在允许的范围之内.由于过热蒸汽温度在减温水量扰动下延迟较大,这种特性使过热蒸汽温度的控制滞后,控制效果不理想.分析现有热电厂锅炉过热蒸汽温度调节系统的控制策略,提出利用锅炉出口蒸汽温度的变化率和炉膛出口烟气温度作为前馈信号,解决过热蒸汽温度调节的滞后性.基于此设计一种锅炉过热蒸汽温度在线模糊PID双模控制方法,并给出详细设计方案.现场运行表明该方法可有效提高原系统的鲁棒性. 相似文献
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Haipeng FangJuan Wang Enmin FengZhijun Li 《Computers & Mathematics with Applications》2011,62(11):4015-4020
In this paper, we establish a distributed parameter coupled system concerning Arctic sea ice temperature field, in which the ice thickness is regarded as a movable inner boundary of the space domain. The existence and continuity of the weak solution to the coupled system are proved. According to the measured data, we establish a parameter identification model with the ice thickness as control variable and the coupled system as constraints. Finally, an optimization algorithm is constructed on the basis of non-overlapping domain decomposition method and semi-implicit difference scheme. Through numerical calculation, we obtain the characteristics of the ice thicknesses and the ice temperatures. 相似文献