共查询到10条相似文献,搜索用时 62 毫秒
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针对花茶烘焙时对温度的精细化要求,提出由模糊控制、神经网络和PID组合算法构成的控制系统,实现对温、湿度的可靠控制,达到对鲜花快速去湿干燥的目的。系统将温度和湿度的误差e和误差率ec作为输入变量进行模糊化处理,确立隶属度函数,通过模糊推理和解模糊化生成输出量,为PID控制系统提供优化的调控因子△K,精准控制执行单元。系统采用RBP神经网络算法对模糊控制过程进行精细实时变量调控,以Delta(δ)函数和梯度下降算法为学习规则调整网络加权系数w、中心向量cij和基宽向量bij。系统利用Matlab软件进行数据仿真,对比传统PID控制和模糊控制,验证模糊神经网络PID组合控制的优越性,数据分析表明组合控制系统对温度的响应速度和数据的精确性都明显改善,扰动补偿和抗干扰能力有效提高,系统鲁棒性更好。 相似文献
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石蜡加热器是浸出车间石蜡尾气回收工艺中的重要设备,石蜡加热器温度闭环系统是典型的非线性、时变、不确定性系统,难以建立精确的数学模型。为提高石蜡加热器电动调节阀温度闭环控制效果,以检测石蜡加热器的温度偏差(e)和温度偏差变化率(ec)为输入,模糊PID控制器的KP、KI、KD为输出,构造了二输入三输出的模糊PID控制器。以西门子S7-300 PLC为下位机,WINCC组态软件为上位机,采用STEP 7软件编写模糊PID控制的算法程序,并将程序下载到S7-300 PLC存储卡中,利用S7-300 PLC对电动调节阀开度进行调节,从而实现石蜡加热器温度闭环控制。模糊PID控制器应用于浸出车间石蜡加热器温度闭环控制系统可以减少系统超调量,具有响应速度快、稳定性高等优点,提高了石蜡加热器温度闭环控制系统的运行效率。 相似文献
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Microwave power modulation during drying was evaluated to guarantee mild temperatures, reducing burning spots when producing sweet potatoes snacks. Samples were peeled, sliced, blanched, and microwave vacuum dried with (MWVDc) and without (MWVD) controlling the temperature (60 °C) with a PID system. MWVD used constant power, while MWVDc adjusted the power input based on samples' temperature target. Moisture content was reduced from 4.5 g g−1 (db) to 0.4 g g−1 (db), resulting in water activity lower than 0.55. MWVD processing time was about 80, 15, and 10 min at 300, 1500, and 2700 W, respectively, resulting in dried samples with dark areas due to hot spots. The power modulation in MWVDc resulted in intermediary drying time (50 min) and uniform color products without burnings. This study demonstrated that automated temperature control leads to high-quality sweet potato chips by microwave processing. 相似文献
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Improving grape quality using microwave vacuum drying associated with temperature control 总被引:3,自引:0,他引:3
ABSTRACT: Microwave (MW) vacuum dehydration using temperature to control the level of MW power demonstrated potential in improving the performance of the process. Product surface temperature measured by an infrared temperature sensor was used to control MW power at any level between 0 and 3 kW. Multiple linear regression analysis indicated an r 2 = 0.942 for prediction of final moisture content and r 2 = 0.985 for prediction of puffed character of grapes based on product temperature, time, specific energy, fresh fruit sugar, and fresh fruit moisture content. Temperature was found to be the most significant predictor. The elemental and compound contents of grapes dried using MW vacuum was compared to sun-dried raisins. The grapes dried using MW vacuum exhibited better preservation. Vitamin A was found in the MW-vacuum-dried grapes but none was detected in the raisins, and Vitamin C, thiamine, and riboflavin were also higher in the MW-vacuum-dried grapes than in the raisins. 相似文献
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