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編號(hào)
無(wú)錫太湖學(xué)院
畢業(yè)設(shè)計(jì)（論文）
相關(guān)資料
題目： FMS自動(dòng)化立體倉(cāng)庫(kù)
堆垛起重機(jī)機(jī)械結(jié)構(gòu)設(shè)計(jì)
信機(jī) 系 機(jī)械工程及自動(dòng)化專(zhuān)業(yè)
學(xué) 號(hào)： 09230102
學(xué)生姓名： 趙 磊
指導(dǎo)教師： 尤麗華 （職稱(chēng)：副教授 ）
2013年5月25日
目 錄
一、畢業(yè)設(shè)計(jì)（論文）開(kāi)題報(bào)告
二、畢業(yè)設(shè)計(jì)（論文）外文資料翻譯及原文
三、學(xué)生“畢業(yè)論文（論文）計(jì)劃、進(jìn)度、檢查及落實(shí)表”
四、實(shí)習(xí)鑒定表
無(wú)錫太湖學(xué)院
畢業(yè)設(shè)計(jì)（論文）
開(kāi)題報(bào)告
題目： FMS自動(dòng)化立體倉(cāng)庫(kù)
堆垛起重機(jī)機(jī)械結(jié)構(gòu)設(shè)計(jì)
信機(jī) 系 數(shù) 控 專(zhuān)業(yè)
學(xué) 號(hào)： 00923102
學(xué)生姓名： 趙 磊
指導(dǎo)教師： 尤麗華 （職稱(chēng)：教授 ）
2012年11月28日
課題來(lái)源
本課題來(lái)源于工程生產(chǎn)實(shí)際，應(yīng)教學(xué)要求，使我們?cè)趯W(xué)習(xí)期間接觸到一些先進(jìn)的技術(shù)裝備和控制技術(shù)等重要知識(shí)，配合有關(guān)課程開(kāi)設(shè)“柔性制造系統(tǒng)綜合實(shí)驗(yàn)”的需求，培養(yǎng)獨(dú)立進(jìn)行科學(xué)研究、綜合分析思考以及實(shí)際動(dòng)手的能力，此畢業(yè)設(shè)計(jì)由此設(shè)立。
科學(xué)依據(jù)
目前自動(dòng)化倉(cāng)庫(kù)在發(fā)達(dá)國(guó)家已相當(dāng)普遍，日本是自動(dòng)化倉(cāng)庫(kù)發(fā)展最快，建造數(shù)量最多的國(guó)家，此外美國(guó)、德國(guó)、瑞士、意大利、英國(guó)、和法國(guó)等國(guó)家也建造了許多自動(dòng)化倉(cāng)庫(kù)，發(fā)展至今，自動(dòng)化倉(cāng)庫(kù)在設(shè)計(jì)、制造自動(dòng)化控制盒計(jì)算機(jī)管理方面的技術(shù)也日趨成熟。
50年代初，美國(guó)美國(guó)出現(xiàn)了采用橋式堆垛起重機(jī)的立體倉(cāng)庫(kù)。60年代初，出現(xiàn)了司機(jī)操作的香道式堆垛起重機(jī)立體倉(cāng)庫(kù)。1963年美國(guó)率先在立體倉(cāng)庫(kù)中采用計(jì)算機(jī)控制技術(shù)，建立了世界上第一座計(jì)算機(jī)控制的立體倉(cāng)庫(kù)。進(jìn)入80年代，我國(guó)對(duì)老式倉(cāng)庫(kù)進(jìn)行技術(shù)改造，開(kāi)始采用自動(dòng)化立體倉(cāng)庫(kù)。1980年由北京機(jī)械工業(yè)自動(dòng)化研究所等單位研制建成我國(guó)第一座自動(dòng)化立體倉(cāng)庫(kù)，在北京汽車(chē)制造廠投產(chǎn)。
據(jù)不完全統(tǒng)計(jì)，目前我國(guó)已建成立體倉(cāng)庫(kù)已有300座左右，其中全自動(dòng)的立體倉(cāng)庫(kù)有50多座，其中高度在12米以上的大型立體倉(cāng)庫(kù)有8座，主要集中在傳統(tǒng)優(yōu)勢(shì)行業(yè)。在此基礎(chǔ)上我國(guó)對(duì)倉(cāng)庫(kù)的研究也向著智能化的方向發(fā)展，但是目前還處于自動(dòng)化倉(cāng)儲(chǔ)的推廣和應(yīng)用階段。
研究?jī)?nèi)容
1.完成FMS自動(dòng)化立體倉(cāng)庫(kù)堆垛起重機(jī)機(jī)械結(jié)構(gòu)設(shè)計(jì)的總體設(shè)計(jì)；
2.完成機(jī)架、行走機(jī)構(gòu)、提升機(jī)構(gòu)和載貨臺(tái)、貨叉等關(guān)鍵部件設(shè)計(jì)；
3.繪制相應(yīng)的二維總裝圖及主要零部件圖紙；
4.設(shè)計(jì)工作量要求：至少完成A0圖紙2張和一份40頁(yè)以上的畢業(yè)論文；
5.查閱相關(guān)外文資料并完成不少于8000字符的外文資料翻譯；
6.完成一份畢業(yè)設(shè)計(jì)實(shí)習(xí)報(bào)告。
擬采取的研究方法、技術(shù)路線(xiàn)、實(shí)驗(yàn)方案及可行性分析
本文從實(shí)際問(wèn)題出發(fā)，以現(xiàn)有設(shè)備為依托，先確定出堆垛機(jī)的總體結(jié)構(gòu)及各部分的結(jié)構(gòu)草圖，然后運(yùn)用理論力學(xué)、材料力學(xué)、機(jī)械設(shè)計(jì)、制造技術(shù)等專(zhuān)業(yè)知識(shí)，并查閱相關(guān)設(shè)計(jì)手冊(cè)，對(duì)其機(jī)械部分進(jìn)行了詳細(xì)的設(shè)計(jì)計(jì)算，包括：機(jī)架、行走機(jī)構(gòu)、提升機(jī)構(gòu)、載貨臺(tái)和貨叉伸縮機(jī)構(gòu)等。設(shè)計(jì)過(guò)程中，以實(shí)現(xiàn)堆垛機(jī)的機(jī)械性能為目的，在滿(mǎn)足其強(qiáng)度、剛度、運(yùn)行穩(wěn)定性等要求的前提下，綜合考慮結(jié)構(gòu)的合理性和所選材料的經(jīng)濟(jì)性，力求達(dá)到高質(zhì)量、低成本。
可行性分析：由此可見(jiàn)，該設(shè)計(jì)方案切實(shí)可行。
研究計(jì)劃及預(yù)期成果
研究計(jì)劃：大致分為如下幾個(gè)階段。第一階段，熟悉老師提供的設(shè)計(jì)資料，設(shè)計(jì)參數(shù)等，仔細(xì)閱讀任務(wù)書(shū)，理清設(shè)計(jì)思路，搜集資料了解研究目標(biāo)，構(gòu)思設(shè)計(jì)方案。第二階段，進(jìn)行方案實(shí)施，根據(jù)設(shè)計(jì)參數(shù)進(jìn)行計(jì)算，按設(shè)計(jì)要求進(jìn)行設(shè)計(jì)使之滿(mǎn)足生產(chǎn)實(shí)際，完成設(shè)計(jì)。第三階段，制定檢測(cè)方案及檢測(cè)方法從而進(jìn)行校核，改善不滿(mǎn)足要求的設(shè)計(jì),最后完成圖紙。
預(yù)期成果： 巷道堆垛起重機(jī)滿(mǎn)足所給自動(dòng)化立體倉(cāng)庫(kù)中各項(xiàng)要求,如:在規(guī)定貨架上自由提取，存放貨物以及完成與輸送系統(tǒng)的配合，速度控制嚴(yán)格滿(mǎn)足穩(wěn)定性的要求等。實(shí)現(xiàn)最優(yōu)化設(shè)計(jì)。
特色或創(chuàng)新之處
國(guó)內(nèi)外其它行業(yè)采用自動(dòng)化倉(cāng)庫(kù)的情況已經(jīng)充分證明，使用自動(dòng)化立體倉(cāng)庫(kù)能夠產(chǎn)生巨大的社會(huì)效益和經(jīng)濟(jì)效益。這些效益主要表現(xiàn)在以下幾個(gè)方面：
1.搞層貨架存儲(chǔ) 由于使用高層貨架，存儲(chǔ)區(qū)可以大幅度地向空間發(fā)展，充分利用倉(cāng)庫(kù)地面和空間，因此節(jié)省了庫(kù)存占地面積，提高了空間利用率。
2.自動(dòng)存取 自動(dòng)化立體倉(cāng)庫(kù)使用機(jī)械和自動(dòng)化設(shè)備，運(yùn)行和處理速度快，提高了作業(yè)效率。
3.計(jì)算機(jī)控制與管理 計(jì)算機(jī)能夠準(zhǔn)確無(wú)誤地對(duì)倉(cāng)庫(kù)的各種信息進(jìn)行存儲(chǔ)和管理，降低了操作人員的勞動(dòng)強(qiáng)度，從而提高倉(cāng)庫(kù)的管理水平。
4.作業(yè)效率明顯提高 能充分保證“先進(jìn)先出”的合理作業(yè)原則。由于計(jì)算機(jī)管理、自動(dòng)作業(yè)，可以方便地實(shí)施貨位和賬目的科學(xué)管理，改善庫(kù)存結(jié)構(gòu)，避免盲目壓貨，并改善勞動(dòng)環(huán)境。
5.節(jié)約費(fèi)用 隨著經(jīng)濟(jì)的高速的發(fā)展，我國(guó)有關(guān)行業(yè)開(kāi)始重視立體庫(kù)的研究，對(duì)于促進(jìn)傳統(tǒng)觀念的轉(zhuǎn)變、提高現(xiàn)代化物流意識(shí)，形成新型的商品流通產(chǎn)業(yè)等方面均產(chǎn)生了強(qiáng)勁的推動(dòng)作用。
已具備的條件和尚需解決的問(wèn)題
已具備的條件：設(shè)計(jì)過(guò)程中所需要的幾種軟件、相關(guān)搜集資料的網(wǎng)站。
尚需解決的問(wèn)題：相關(guān)文獻(xiàn)資料的缺乏，對(duì)一些結(jié)構(gòu)設(shè)計(jì)部分的具體設(shè)計(jì)指導(dǎo)，以及三維軟件的高級(jí)運(yùn)用技巧。
指導(dǎo)教師意見(jiàn)
指導(dǎo)教師（簽名）： 年 月 日
系主任（簽名）： 年 月 日
英文原文：
Realization of Neural Network Inverse System with PLC in Variable Frequency Speed-Regulating System
Abstract. The variable frequency speed-regulating system which consists of an induction motor and a general inverter, and controlled by PLC is widely used in industrial field. .However, for the multivariable, nonlinear and strongly coupled induction motor, the control performance is not good enough to meet the needs of speed-regulating. The mathematic model of the variable frequency speed-regulating system in vector control mode is presented and its reversibility has been proved. By constructing a neural network inverse system and combining it with the variable frequency speed-regulating system, a pseudo-linear system is completed, and then a linear close-loop is designed to get high performance. Using PLC, a neural network inverse system can be realized in system. The results of experiments have shown that the performances of variable frequency speed-regulating system can be improved greatly and the practicability of neural network inverse control was testified.
1.Introduction
In recent years, with power electronic technology, microelectronic technology and modern control theory infiltrating into AC electric driving system, inverters have been widely used in speed-regulating of AC motor. The variable frequency speed-regulating system which consists of an induction motor and a general inverter is used to take the place of DC speed-regulating system. Because of terrible environment and severe disturbance in industrial field, the choice of controller is an important problem. In reference [1][2][3], Neural network inverse control was realized by using industrial control computer and several data acquisition cards. The advantages of industrial control computer are high computation speed, great memory capacity and good compatibility with other software etc. But industrial control computer also has some disadvantages in industrial application such as instability and fallibility and worse communication ability. PLC control system is special designed for industrial environment application, and its stability and reliability are good. PLC control system can be easily integrated into field bus control system with the high ability of communication configuration, so it is wildly used in recent years, and deeply welcomed. Since the system composed of normal inverter and induction motor is a complicated nonlinear system, traditional PID control strategy could not meet the requirement for further control. Therefore, how to enhance control performance of this system is very urgent.
The neural network inverse system [4][5] is a novel control method in recent years. The basic idea is that: for a given system, an inverse system of the original system is created by a dynamic neural network, and the combination system of inverse and object is transformed into a kind of decoupling standardized system with linear relationship. Subsequently, a linear close-loop regulator can be designed to achieve high control performance. The advantage of this method is easily to be realized in engineering. The linearization and decoupling control of normal
system can realize using this method.
Combining the neural network inverse into PLC can easily make up the insufficiency of solving the problems of nonlinear and coupling in PLC control system. This combination can promote the application of neural network inverse into practice to achieve its full economic .
In this paper, firstly the neural network inverse system method is introduced, and mathematic model of the variable frequency speed-regulating system in vector control mode is presented. Then a reversible analysis of the system is performed, and the methods and steps are given in constructing NN-inverse system with PLC control system. Finally, the method is verified in
traditional PI control and NN-inverse control.
2.Neural Network Inverse System Control Method
The basic idea of inverse control method [6] is that: for a given system, anα-th integral inverse system of the original system is created by feedback method, and combining the inverse system with original system, a kind of decoupling standardized system with linear relationship is obtained, which is named as a pseudo linear system as shown in Fig.1. Subsequently, a linear close-loop regulator will be designed to achieve high control performance.
Inverse system control method with the features of direct, simple and easy to understand does not like differential geometry method [7], which is discusses the problems in "geometry domain". The main problem is the acquisition of the inverse model in the applications. Since non-linear system is a complex system, and desired strict inverse is very difficult to
obtain, even impossible. The engineering application of inverse system control don’t meet the expectations. As neural network has non-linear approximate ability, especially for nonlinear
the powerful tool to solve the problem.
a ? th NN inverse system integrated inverse system with non-linear ability of the neural network can avoid the troubles of inverse system method. Then it is possible to apply inverse control method to a complicated non-linear system. a ? th NN inverse system method needs less system information such as the relative order of system, and it is easy to obtain the inverse model by neural network training. Cascading the NN inverse system with the original system, a pseudo-linear system is completed. Subsequently, a linear close-loop regulator will be designed.
3. Mathematic Model of Induction Motor Variable Frequency
Speed-Regulating System and Its Reversibility
Induction motor variable frequency speed-regulating system supplied by the inverter of tracking current SPWM can be expressed by 5th order nonlinear model in d-q two-phase rotating coordinate. The model was simplified as a 3-order nonlinear model. If the delay of inverter is neglected,
the model is expressed as follows:
(1)
where denotes synchronous angle frequency, and is rotate speed. are stator’s current, and are rotor’s flux linkage in
(d,q)axis. is number of poles. is mutual inductance, and is rotor’s inductance. J is moment of inertia.is rotor’s time constant, and
is load torque.
In vector mode, then
Substituted it into formula (1), then
(2)
Taking reversibility analyses of forum (2), then
The state variables are chosen as follows
Input variables are
Taking the derivative on output in formula(4), then
(5)
(6)
Then the Jacobi matrix is Realization of Neural Network Inverse System with PLC
(7)
(8)
As so and system is reversible. Relative-order of system is
When the inverter is running in vector mode, the variability of flux linkage can be neglected (considering the flux linkage to be invariableness and equal to the rating). The original system was simplified as an input and an output system concluded by forum (2).
According to implicit function ontology theorem, inverse system of formula (3)
can be expressed as
(9)
When the inverse system is connected to the original system in series, the pseudo linear compound system can be built as the type of
4. Realization Steps of Neural Network Inverse System
4.1 Acquisition of the Input and Output Training Samples
Training samples are extremely important in the reconstruction of neural network inverse system. It is not only need to obtain the dynamic data of the original system, but also need to obtain the static date. Reference signal should include all the work region of original system, which can be ensure the approximate ability. Firstly the step of actuating signal is given corresponding every 10 HZ form 0HZ to 50HZ, and the responses of open loop are obtain. Secondly a random tangle signal is input, which is a random signal cascading on the step of actuating signal every 10 seconds, and the close loop responses is obtained. Based on these inputs, 1600 groups
training samples are gotten.
4.2 The Construction of Neural Network
A static neural network and a dynamic neural network composed of integral is used to construct the inverse system. The structure of static neural network is 2 neurons in input layer, 3 neurons in output layer, and 12 neurons in hidden layer. The excitation function of hidden neuron is monotonic smooth hyperbolic tangent function. The output layer is composed of neuron with linear threshold excitation function. The training datum are the corresponding speed of open-loop, close-loop, first order
derivative of these speed, and setting reference speed. After 50 times training, the training error of neural network achieves to 0.001. The weight and threshold of the neural network are saved. The inverse model of original
system is obtained.
5 .Experiments and Results
5.1 Hardware of the System
The hardware of the experiment system is shown in Fig 5. The hardware system includes upper computer installed with Supervisory & Control configuration software WinCC6.0 [8], and S7-300 PLC of SIEMENS, inverter, induction motor and photoelectric coder.
PLC controller chooses S7-315-2DP, which has a PROFIBUS-DP interface and a MPI
is connected with S7-300 by CP5611 using MPI protocol.
The type of inverter is MMV of SIEMENS. It can communicate with SIEMENS PLC by
inverter in this system.
5.2 Software Program
5.2.1 Communication Introduction
MPI (Mu Point Interface) is a simple and inexpensive communication strategy using in slowly and non-large data transforming field. The data transforming between and PLC is not large,
chosen.
The MMV inverter is connected to the PROFIBUS network as a slave station, which is mounted with CB15 PROFIBUS module. PPO1 or PPO3 data type can be chosen. It permits to send the control data directly to the inverter addresses, or to use the system function blocks of
SFC14/15.
OPC can efficiently provide data integral and intercommunication. Different type servers and clients can access data sources of each other. Comparing with the traditional mode of software and hardware development, equipment manufacturers only need to develop one driver. This can short the development cycle, save manpower resources, and simplify the structure
of the entire control system.
Variety data of the system is needed in the neural network training of , which can not obtain by reading from PLC or directly. So OPC technology can be used l to obtain the needed data between . Setting as OPC DA server, an OPC client is constructed in Excel by VBA. System real time data is and to Excel by, and then the data in Excel is transform to for offline
training to get the inverse system of original system.
5.2.2 Control Program
Used STL to program the communication and data acquisition and control algorithm subroutine in STEP7 V5.2, velocity sample subroutine and storage subroutine are programmed in regularly interrupt A, and the interrupt cycle chooses 100ms. In order to minimum the cycle time of A to prevent the run time of A exceeding 100ms and system error, the control procedure and
procedure B.
In neural network algorithm normalized the training samples is need to speed up the rate of n
input and output data before the final training.
5.3 Experiment Results
When speed reference is square wave signal with 100 seconds cycle, where the inverter is
tracking performance of neural network control is better than traditional PI control.
When speed reference keeps in constant, and the load is reduced to no load at 80 seconds, and increased to full load at 120 seconds, the response curves of speed with traditional PI control and neural network inverse control are shown in Fig. 11 and 12 respectively. It is clearly that the performance of resisting the load disturbing with neural network inverse
control is better than the traditional PI control.
(Speed response in PI control)
(Speed response in neural network inverse control)
6. Conclusion
In order to improve the control performance of PLC Variable Frequency Speed-regulating System, neural network inverse system is used. A mathematic model of variable frequency speed-regulating system was given, and its reversibility was testified. The inverse system and original system is compound to construct the pseudo linear system and linear control method is design to control. With experiment, neural network inverse system with PLC has its effectiveness and its feasibility in industry application.
中文譯文
PLC變頻調(diào)速的網(wǎng)絡(luò)反饋系統(tǒng)的實(shí)現(xiàn)
摘要。變頻調(diào)速系統(tǒng),包括一個(gè)異步電動(dòng)機(jī)和通用逆變器、且PLC控制被廣泛地應(yīng)用于工業(yè)領(lǐng)域。然而,對(duì)多變量、非線(xiàn)性和強(qiáng)耦合的異步電機(jī)的控制性能卻不足,不能很好地滿(mǎn)足客戶(hù)的調(diào)速要求。該數(shù)學(xué)模型的變頻調(diào)速系統(tǒng)提出了矢量控制方式,其可逆轉(zhuǎn)性得到證實(shí)。通過(guò)構(gòu)建一種基于神經(jīng)網(wǎng)絡(luò)的逆系統(tǒng),并結(jié)合變頻調(diào)速系統(tǒng),pseudo-linear系統(tǒng)被完成了,并且為了得到性能優(yōu)良的系統(tǒng)采用了一個(gè)線(xiàn)性閉環(huán)調(diào)節(jié)器。采用PLC、神經(jīng)網(wǎng)絡(luò)逆系統(tǒng)在實(shí)際系統(tǒng)可以實(shí)現(xiàn)。實(shí)驗(yàn)結(jié)果表明變頻調(diào)速系統(tǒng)的性能得到了很大的提高，并且神經(jīng)網(wǎng)絡(luò)反饋控制的可行性得到了驗(yàn)證。
1. 導(dǎo)論
近年來(lái),隨著電力電子技術(shù)、微電子技術(shù)和現(xiàn)代控制理論,逐漸涉及到交流電機(jī)系統(tǒng),這些技術(shù)已經(jīng)廣泛應(yīng)用于變頻器調(diào)速的AC馬達(dá)。變頻調(diào)速系統(tǒng),包括一個(gè)異步電動(dòng)機(jī)和通用逆變器，用來(lái)代替直流調(diào)速系統(tǒng)。由于在工業(yè)領(lǐng)域中的糟糕的環(huán)境和嚴(yán)重的干擾,選擇控制器是一個(gè)十分重要的問(wèn)題。在文獻(xiàn)[1][2][3],介紹了利用工業(yè)控制計(jì)算機(jī)和數(shù)據(jù)采集卡實(shí)現(xiàn)了神經(jīng)網(wǎng)絡(luò)反饋控制。工業(yè)控制計(jì)算機(jī)的優(yōu)勢(shì)有較高的計(jì)算速度，龐大的記憶能力以及與其他軟件良好的兼容性等。但是工業(yè)控制計(jì)算機(jī)在工業(yè)應(yīng)用上也有一些不足，比如運(yùn)行不穩(wěn)定,不可靠及更惡劣的通信能力。可編程序控制器(PLC)控制系統(tǒng)是專(zhuān)為工業(yè)環(huán)境中的應(yīng)用而設(shè)計(jì)的,它的穩(wěn)定性和可靠性好。PLC控制系統(tǒng),可以很容易地集成到現(xiàn)場(chǎng)總線(xiàn)控制系統(tǒng)并得到高性能的通信結(jié)構(gòu),所以它在近年來(lái)被廣泛地使用,并且深受歡迎。該系統(tǒng)由普通的逆變器和異步電機(jī)組成，是一種復(fù)雜的非線(xiàn)性系統(tǒng),傳統(tǒng)的PID控制策略,并不能滿(mǎn)足要求和進(jìn)一步控制。因此,如何加強(qiáng)系統(tǒng)的控制性能是非常迫切的事情。
神經(jīng)網(wǎng)絡(luò)逆系統(tǒng)[4][5], 在未來(lái)幾年里將是一種新型的控制方法。其基本的想法是:對(duì)于一個(gè)給定的系統(tǒng),原系統(tǒng)的逆系統(tǒng)是由一個(gè)動(dòng)態(tài)神經(jīng)網(wǎng)絡(luò)引起的,對(duì)象信號(hào)和反饋信號(hào)的組合系統(tǒng)被轉(zhuǎn)化成一種線(xiàn)性關(guān)系的解耦標(biāo)準(zhǔn)系統(tǒng)。隨后,一個(gè)線(xiàn)性閉環(huán)調(diào)節(jié)器設(shè)計(jì)可以達(dá)到較高的控制性能。該方法的優(yōu)點(diǎn)是在工程上很容易實(shí)現(xiàn)。在線(xiàn)性化及其解耦控制正常的非線(xiàn)性系統(tǒng)能實(shí)現(xiàn)采用這種方法。
把神經(jīng)網(wǎng)絡(luò)反饋結(jié)合到可編程序控制器(PLC)上就可以很容易地彌補(bǔ)不足的問(wèn)題，解決在PLC控制系統(tǒng)上的非線(xiàn)性耦合。這個(gè)組合可以促進(jìn)神經(jīng)網(wǎng)絡(luò)反饋付諸實(shí)踐，來(lái)實(shí)現(xiàn)其全部的經(jīng)濟(jì)效益和社會(huì)效益。
在這篇文章中，首先對(duì)神經(jīng)網(wǎng)絡(luò)反饋方法進(jìn)行了介紹,并且描述了采用矢量控制的變頻調(diào)速系統(tǒng)的數(shù)學(xué)模型。然后是對(duì)反饋系統(tǒng)進(jìn)行分析的的介紹,并給出了關(guān)于PLC控制系統(tǒng)中構(gòu)造NN-反饋系統(tǒng)的方法和步驟。最后,該方法在實(shí)驗(yàn)中被驗(yàn)證,并將傳統(tǒng)的PI控制和NN-反饋控制進(jìn)行了對(duì)比。
2. 神經(jīng)反饋網(wǎng)絡(luò)控制方法
基本的反饋控制方法[6]就是:對(duì)于一個(gè)給定的系統(tǒng)、一種α-th由反饋方法建立的完整的反饋系統(tǒng),并結(jié)合反饋系統(tǒng)與原系統(tǒng)的特點(diǎn),提出了一種解耦的線(xiàn)性關(guān)系,以標(biāo)準(zhǔn)化體系,并命名為偽線(xiàn)性系統(tǒng)。隨后,一個(gè)線(xiàn)性閉環(huán)調(diào)節(jié)器運(yùn)行并將達(dá)到較高的控制性能。
當(dāng)在“幾何領(lǐng)域”討論這些問(wèn)題時(shí)，反饋系統(tǒng)控制方法并不像微分幾何方法，其特點(diǎn)是直接，簡(jiǎn)單，易于理解。主要的問(wèn)題是怎樣在應(yīng)用軟件中獲得反饋模型。由于非線(xiàn)性系統(tǒng)是一個(gè)復(fù)雜的系統(tǒng),所以很難要求嚴(yán)格解析反饋信號(hào),這甚至是不可能的。反饋系統(tǒng)控制在工程應(yīng)用中不能達(dá)到期望值。作為神經(jīng)網(wǎng)絡(luò)非線(xiàn)性逼近能力,尤其是對(duì)于非線(xiàn)性的復(fù)雜系統(tǒng),它會(huì)是來(lái)解決問(wèn)題的強(qiáng)大工具。反饋系統(tǒng)集成了具有非線(xiàn)性逼近能力的反饋系統(tǒng)，其中具有非線(xiàn)性逼近能力的反饋系統(tǒng)能夠避免使用反饋方法帶來(lái)的麻煩。這樣就可能，運(yùn)用反饋控制方法去控制一個(gè)復(fù)雜的非線(xiàn)性系統(tǒng)。a ? th NN 反饋系統(tǒng)的控制方法只需要較少的系統(tǒng)信息，比如與系統(tǒng)相關(guān)的命令，并且容易獲得運(yùn)行網(wǎng)絡(luò)的反饋模型。原系統(tǒng)的層疊式的 NN反饋系統(tǒng),會(huì)形成一個(gè)偽線(xiàn)性系統(tǒng)。然后,一個(gè)線(xiàn)性閉環(huán)調(diào)節(jié)校準(zhǔn)器將工作。
3. 異步電機(jī)變頻調(diào)速系統(tǒng)的數(shù)學(xué)模型和它的反饋性能
異步電機(jī)變頻調(diào)速系統(tǒng)提供的跟蹤電流正弦脈寬調(diào)制逆變器可以表示為非線(xiàn)性模型在兩相循環(huán)的協(xié)調(diào)。該模型簡(jiǎn)化為一個(gè)3-order非線(xiàn)性模型。如果忽略逆變器的延遲,該模型表述如下:
（1）
（表示同步角頻率；表示轉(zhuǎn)速；
表示定子的電流；表示轉(zhuǎn)子在（qd）軸線(xiàn)上的不穩(wěn)定部分；
表示點(diǎn)的數(shù)量；表示互感系數(shù)；表示慣性轉(zhuǎn)矩；
表示轉(zhuǎn)子的時(shí)間常數(shù)；表示負(fù)載轉(zhuǎn)矩。）
用矢量模式,得
代進(jìn)公式(1),得
（2）
可逆轉(zhuǎn)性分析(2),得
（3） （4）
可供選擇的狀態(tài)變量如下
輸入變量
由公式(4)得出結(jié)果,得
（5）
（6）
然后雅可比矩陣
（7）
（8）
作為 所以并且系統(tǒng)是可逆的。
相關(guān)的系統(tǒng)是
當(dāng)變頻器運(yùn)行模式的變化,在矢量磁鏈的可以忽略的磁鏈(考慮到是恒定,等于等級(jí))。原系統(tǒng)簡(jiǎn)化為一個(gè)輸入和輸出系統(tǒng)訂立的(2)。
根據(jù)隱函數(shù)定理，公式(3)的反饋系統(tǒng)可以表達(dá)為:
（9）
當(dāng)反饋系統(tǒng)連續(xù)連接到原系統(tǒng)時(shí)，偽線(xiàn)性復(fù)合系統(tǒng)形成類(lèi)型。
4. 網(wǎng)絡(luò)反饋系統(tǒng)的實(shí)現(xiàn)步驟
4.1 輸入與輸出的運(yùn)行樣本的采集
采樣對(duì)網(wǎng)絡(luò)反饋系統(tǒng)的建立是極其重要的。它不僅需要獲得原系統(tǒng)的動(dòng)態(tài)數(shù)據(jù),還需要獲得了靜態(tài)的數(shù)據(jù)。參考信號(hào)應(yīng)該包括原始系統(tǒng)所有的工作范圍,并確保近似。信號(hào)的欲處理的第一階段是從每0HZ到50HZ中得到10HZ，并得到開(kāi)環(huán)響應(yīng)。第二階段是混亂信號(hào)的輸入，當(dāng)每10秒鐘出現(xiàn)預(yù)處理信號(hào)時(shí)，隨機(jī)信號(hào)輸入,并得到閉環(huán)響應(yīng)?；谶@些輸入,將得到1600組得到運(yùn)行樣本。
4.2 網(wǎng)絡(luò)的建設(shè)
靜態(tài)神經(jīng)網(wǎng)絡(luò)和動(dòng)態(tài)神經(jīng)網(wǎng)絡(luò)的完美組合將能構(gòu)建一個(gè)反饋系統(tǒng)。靜態(tài)神經(jīng)網(wǎng)絡(luò)的結(jié)構(gòu)是由2個(gè)輸入層的神經(jīng)元，3個(gè)輸出層的神經(jīng)元和12個(gè)隱蔽層的神經(jīng)元組成。隱藏神經(jīng)元的激勵(lì)函數(shù)是單調(diào)平滑雙曲正切函數(shù)。輸出層是由線(xiàn)性臨界激勵(lì)函數(shù)的神經(jīng)元組成。運(yùn)行數(shù)據(jù)是這些速度的開(kāi)環(huán)，閉環(huán)的相對(duì)應(yīng)速度和設(shè)置的參考的速度。50次運(yùn)行之后，神經(jīng)網(wǎng)絡(luò)的運(yùn)行錯(cuò)誤達(dá)到0.001。神經(jīng)網(wǎng)絡(luò)的負(fù)荷和臨界值被保存下來(lái)。并得到原系統(tǒng)的反饋模型。
5. 實(shí)驗(yàn)和結(jié)果
5.1 系統(tǒng)硬件
硬件系統(tǒng)包括上層監(jiān)督計(jì)算機(jī)安裝，控制結(jié)構(gòu)軟件WinCC6.0,西門(mén)子S7-300PLC，變頻器，異步電動(dòng)機(jī)和光電編碼器。
選擇S7-315-2DP PLC控制器,它有一個(gè)PROFIBUS-DP接口和一個(gè)MPI接口。高速采集模塊是FM350-1。WinCC用MPI協(xié)議被CP5611貫穿到S7-300。
這個(gè)逆變器的類(lèi)型是西門(mén)子的MMV。西門(mén)子的PLC能兼容美國(guó)的協(xié)議。在這個(gè)系統(tǒng)上ACB15模塊被增加在逆變器上。
5.2 軟件編程
5.2.1 通信介紹
MPI(多點(diǎn)接口)是一種簡(jiǎn)單、便宜的通訊策略，運(yùn)用在運(yùn)行慢，非大型數(shù)據(jù)轉(zhuǎn)換的場(chǎng)合。在WinCC與PLC之間的數(shù)據(jù)轉(zhuǎn)換不是很大,所以選擇MPI協(xié)議。
MMV變頻器作為從動(dòng)裝置連接到PROFIBUS網(wǎng)絡(luò),并安裝到CB15 PROFIBUS模塊上。PPO1或PPO3的數(shù)據(jù)類(lèi)型可供選擇。它允許控制信號(hào)直接發(fā)送到變頻地址,或者使用STEP7V5.2 SFC14/15的系統(tǒng)功能模塊。
OPC能有效的提供完整的數(shù)據(jù)和通信能力。不同類(lèi)型的服務(wù)器和客戶(hù)機(jī)可以存取彼此的數(shù)據(jù)來(lái)源。比較傳統(tǒng)的軟件模式和硬件發(fā)展,設(shè)備生產(chǎn)商只需要培養(yǎng)一個(gè)操作員。這樣可以縮短開(kāi)發(fā)周期,節(jié)省人力資源,并簡(jiǎn)化了整個(gè)控制系統(tǒng)的結(jié)構(gòu)。
矩陣實(shí)驗(yàn)室的神經(jīng)網(wǎng)絡(luò)運(yùn)行需要系統(tǒng)各種各樣數(shù)據(jù)的時(shí)候，這些數(shù)據(jù)不能從PLC或WinCC直接讀取。所以O(shè)PC技術(shù)可以用來(lái)獲得在WinCC和Exce之中所需的數(shù)據(jù)。設(shè)置WinCC作為OPC DA的服務(wù)器,一個(gè)OPC客戶(hù)將被很好的建立關(guān)于VBA。系統(tǒng)的實(shí)時(shí)數(shù)據(jù)被WinCC讀取并寫(xiě)到Excel上,然后Excel上的數(shù)據(jù)被轉(zhuǎn)換到矩陣實(shí)驗(yàn)室為在離線(xiàn)運(yùn)行時(shí)獲得原系統(tǒng)的反饋系統(tǒng)。
5.2.2控制程序
通常用STEP7 V5.2的標(biāo)準(zhǔn)模板庫(kù)來(lái)對(duì)通訊，數(shù)據(jù)采集和控制算法進(jìn)行編程，速度采樣程序和存儲(chǔ)程序被編程為有規(guī)律的中斷程序A，中斷周期為100毫秒。為了阻止程序A運(yùn)行時(shí)間超過(guò)100毫秒，減小程序的運(yùn)行周期和系統(tǒng)錯(cuò)誤，控制步驟和神經(jīng)網(wǎng)絡(luò)算法被編程為主程序B。
神經(jīng)網(wǎng)絡(luò)算法標(biāo)準(zhǔn)化對(duì)運(yùn)行采樣來(lái)說(shuō)是必要的以便加快信號(hào)收集速度，在最終運(yùn)行之前輸入和輸出信號(hào)乘以一個(gè)放大系數(shù)。
5.3 實(shí)驗(yàn)結(jié)果
當(dāng)速度參照是100秒每周期的方波信號(hào)時(shí),逆變器運(yùn)行的是矢量模式。結(jié)果表明,神經(jīng)網(wǎng)絡(luò)控制的跟蹤性能均優(yōu)于傳統(tǒng)的常規(guī)PI控制。
當(dāng)速度參照保持恒定時(shí),經(jīng)過(guò)80秒時(shí)間，負(fù)荷降低到?jīng)]有負(fù)荷,經(jīng)過(guò)120秒時(shí)間,負(fù)荷增加到滿(mǎn)負(fù)荷，所以在傳統(tǒng)控制下的速度響應(yīng)曲線(xiàn)和網(wǎng)絡(luò)反饋控制下的速度響應(yīng)曲線(xiàn)如下圖所示。很明顯,在穩(wěn)定性能上，網(wǎng)絡(luò)反饋控制的負(fù)載擾動(dòng)優(yōu)于傳統(tǒng)的PI控制的負(fù)載擾動(dòng)。
（PI控制下的速度響應(yīng)） （網(wǎng)絡(luò)反饋控制下的速度響應(yīng)）
6. 結(jié)論
為了改善PLC變頻調(diào)速系統(tǒng)的控制性能，因而神經(jīng)網(wǎng)絡(luò)反饋系統(tǒng)被使用。并給出了一個(gè)變頻調(diào)速系統(tǒng)的數(shù)學(xué)模型,且其可逆轉(zhuǎn)性得到了檢驗(yàn)。反饋系統(tǒng)和原系統(tǒng)被組合并構(gòu)建成偽線(xiàn)性系統(tǒng)，并設(shè)計(jì)了線(xiàn)性控制的方法進(jìn)行控制。通過(guò)實(shí)驗(yàn),PLC神經(jīng)網(wǎng)絡(luò)的反饋系統(tǒng)在工業(yè)應(yīng)用中具有有效性和可行性的到了驗(yàn)證。