CN103120113A - Small-sized area irrigation system based on ZigBee - Google Patents

Abstract

The invention belongs to the field of novel agriculture, and discloses a small-sized area irrigation system based on ZigBee. The small-sized area irrigation system based on the ZigBee is designed to be an intelligent irrigation system composed of a terminal node, a route control node, a Sink node and a central monitoring system. Real-time monitoring and automatic control of farmland soil moisture content are achieved. According to a short-range wireless sensing network based on a ZigBee protocol, an automatic control mode is adopted, not only can the problems that a traditional automatic irrigation control system is high in cost and inconvenient to expand, electricity is difficult to supply, an algorithm is not accurate and the like be solved, but also strong information processing functions of the small-sized area irrigation system lay a foundation for optimizing decisions.

Description

A kind of small area irrigation system based on ZigBee

One, technical field

The present invention is based on the intelligent irrigation system of ZigBee technology, belongs to field of intelligent control.

Two, background technology

China is a large agricultural country, the serious poor country of a water resource simultaneously, wherein Water Consumption in Agriculture accounts for 75% of total water amount, but the availability of China's agricultural irrigation water is only 45% at present, and water utilization rate high country has reached 80% left and right, and the wretched insufficiency of water resource is restricting the development of China's agricultural.

Drought and water shortage has become the main restriction of China's agricultural stable development and grain security supply because of rope, is secondly urban water shortage.In city, 670, the whole nation, more than 400 city lack of water is in various degree arranged, water deficit is 60 billion cubic meters approximately, because lack of water affects more than 2,000 hundred million yuan of industrial output values. to the middle of this century, China's population will be increased to 1,300,000,000, and irrigated area develops into 6,333 ten thousand square metres, and the Population Urbanization rate will increase to 56% left and right from present 28.7%, economy will reach world's level of medium-developed country, and the supply of water will become the important restriction factor of whole socio-economic development.China's city domestic water is in short supply on the one hand, and waste is also very serious on the other hand.

Reasonably promote automation and control in irrigation system, not only can improve water utilization rate, alleviate the contradiction that is becoming tight water resource day, can also increase the output of crops, reduce the cost of agricultural product.The level of irrigation system automation is low is also the main cause that restricts China's high-efficiency agriculture development.Some countries such as Israel, Japan, the U.S. have adopted advanced Water Saving Irrigation System.Being developed to insufficient irrigation by traditional abundant irrigation, Irrigation Water is carried out monitoring and prediction, actual dynamic management. soil tilth monitored by the employing sensor and crops can grow, and realizes the automation of water management.High-efficiency agriculture and precision agriculture require us must improve the availability of water resource.

The ZigBee radio network technique that is day by day rising recent years in addition progressively moves to maturity, and it is comprised of the wireless ordinary node of a large amount of ZigBee and one or several aggregation node, carries out data interaction by the ZigBee wireless transmission method between ordinary node.Wherein ordinary wireless node is responsible for image data, gets mode by routing node single-hop or multi-hop and passes to aggregation node and carry out data fusion, processing.

Three, summary of the invention

The object of the present invention is to provide one based on the intelligent irrigation system of ZigBee.Specific implementation comprises the following steps:

(1) humiture collection of soil: gather by the SHT11 sensor;

(2) transmission of information: by ZigBee, the temp. and humidity that collects is reached the Sink node from terminal node via routing node, transfer data to PC by serial ports at last.Communication between each radio node is identified by ID (self numbering);

(3) fusion treatment of data: utilize the D-S data fusion that the value of multisensor is merged, carry out at last decision-making;

(4) demonstration of data, inquiry and deletion: utilize VB to write the interface, the ACCESS database is preserved so that inquiry from now on and operation the data that gather.

The invention has the advantages that identification accurately, and can in time process arid situation.

Description of drawings

Fig. 1 is the hardware block diagram that uses in the present invention;

Fig. 2 grid topological structure schematic diagram.

Fig. 3 monitoring system interface.

Embodiment:

The present invention will be further described below in conjunction with accompanying drawing and instantiation:

A) collection of soil temperature and humidity:

By reference to the accompanying drawings 1, utilize the I that has that Switzerland Sensirion company produces ²The accurate digital relative moisture of the monolithic whole school of C EBI and temperature sensor. this sensor adopts unique CMOSens TM technology, has digital output, exempts to debug, non-calibrating, exempts from peripheral circuit and full characteristics of exchanging.

The points for attention of installation of sensors:

1) sensor need be placed on horizontal level, in order to avoid moisture is assembled at two ends;

2) sensor should directly not be placed in the place that is exposed under sunlight;

3) not the close power line of transmission line;

4) when a more than sensor is arranged, the minimum range of installing between them is 1 meter, in order to avoid possible reading problem occurs.

in addition, the riding position of soil temperature-moisture sensor needs to consider. in irrigation canals and ditches are irrigated, sensor is placed on 2/3 length place of irrigation canals and ditches, that is to say 1/3 place of afterbody, because it is exuberant that this zone is moisture, also possible irrigate the poorest place. when tree is arranged, sensor should be placed on trunk limit, the southeast, because this regional sun lights many. in sprinkling irrigation, spray water more even, but also be subject to the difference of soil property, what and landform of permeable layers and make moisture inhomogeneous. just note following situations during installation of sensors: if set, sensor must be placed in the formation of trees. guarantee that sensor can not be placed on the back of barrier, such as shrub etc., because these things may affect the moisture distribution in working sensor zone.

B) the D-S data fusion of multisensor:

What the present invention used is a kind of D-S data anastomosing algorithm based on Weighted Similarity, and this algorithm is the size according to similarity between the evidence body, adjusts the weights of each evidence body. the step of algorithm is as follows:

Step 1: suppose n evidence body, at first use formula $d_{\mathrm{BPA}}(m_1,m_2)=\sqrt{\frac{1}{2}{(m_1-m_2)}^T\underset{=}{D}(m_1-m_2)}$ Calculate the distance between the evidence body in twos, the formula that here similarity is calculated is defined as:

S _ij=1-d _ij(i, j=1,2 ..., n). consisting of s-matrix is: $S={\left[\begin{array}{cccc}1& s_{12}& \·\·\·& s_{1n}\\ s_{21}& 1& \·\·\·& s_{2n}\\ \·& \·& & \·\\ \·& \·& & \·\\ \·& \·& & \·\\ s_{n1}& s_{n2}& \·\·\·& 1\end{array}\right]}_{n\×n}$

Suppose that i evidence body weights coefficient is w _i, its computing formula is:

λw _i＝w ₁S _1，i+w ₂S _2，i+...+w _nS _n，i

Make w=(w ₁, w ₂..., w _n) ^T, can draw λ w=with linear algebra knowledge ^STW, wherein w is that matrix S is eigen vector, w _iIt is initial weight ^[26].

Step 2: after asking for each weights, choose the w of the maximum of these weights the insides _max.

w _max=max (w ₁, w ₂..., w _n), use

Represent that i evidence accounts for all evidences ^{[27[28] [29]}The size of proportion is designated as σ _i, and be called factor of influence, if the similarity degree between some evidences and other evidences is higher, to affect in fusion rule be larger to this evidence so, its weight w _iLarger, factor of influence σ so _iAlso just larger, it is apparent in view describing evidential function with factor of influence.

Step 3: after determining factor of influence, its conflict coefficient is:

$k^d=\frac{1}{2}(\underset{A_i\∩B_j=\mathrm{\Φ}}{\mathrm{\Σ}}{m}_1\left(A_i\right)\·m_2\left(B_j\right)+d(m_1,m_2))$

Step 4: if clash between evidence, need evidence is revised ^[30], here take two evidences as example, revised fusion rule is:

$m\left(A\right)=m_1\⊕m_2=\underset{A=A_i\∩B_j}{\mathrm{\Σ}}{m}_1\left(A_i\right)\·m_2\left(B_j\right)+\frac{1}{2}\·k^d\underset{i=1}{\overset{2}{\mathrm{\Σ}}}{\mathrm{\σ}}_i{m}_i\left(A\right)$

C) Simulation results

Do emulation experiment as an example of humidity example, now suppose identification framework be Θ=a, b, c}, wherein a={ is suitable, humidity value is greater than 70%}; Drought during b={ is light, humidity value is at 45%-70%}; The heavy drought of c={, humidity value carries out three features of identification framework are carried out data observation with four sensors less than 45%}, consists of four evidence bodies, and their weights are allocated as follows:

Basic probability assignment

Merge for a plurality of evidence bodies, two evidences first can be merged, then with other merge, and fusion sequence is unaffected.According to this theory, take here first with m ₁And m ₂Merge, obtain

[σ ₁, σ ₂]=[0.9608,1]; Then m after merging ₁₂Same m ₃Merge, obtain [σ ₁, σ ₂]=[0.2655,1]; At last with m ₁₂₃Same m ₄Combination obtains

[σ ₁, σ ₂]=[0.095,1].Can find out from the conflict coefficient size, at m ₁And m ₂After combination, conflict or fairly obvious between evidence, along with the evidence source constantly adds and to the modification of conflicting evidence, Become by 0.985

0.28, the method has well reduced the evidence conflict; Can see that from the factor of influence size evidence that adds that makes new advances plays a major role to fusion, its factor of influence perseverance is 1, when this shows the sensor image data, very important, if there is a certain sensor to break down, can accurately orient which sensor with the method fault has occured, the below is through result after merging.

Fusion results

Can be got by fusion results, the soil of this moment does not need to irrigate.

Claims (4)

1. real-time intelligent irrigation system based on ZigBee, this system contains following steps:

(1) humiture collection of soil: gather by the SHT11 sensor;

(2) transmission of information: by ZigBee, the temp. and humidity that collects is reached the Sink node from terminal node via routing node, transfer data to PC by serial ports at last.Communication between each radio node is identified by ID (self numbering);

(3) fusion treatment of data: utilize the D-S data fusion that the value of multisensor is merged, carry out at last decision-making;

(4) demonstration of data, inquiry and deletion: utilize VB to write the interface, the ACCESS database is preserved so that inquiry from now on and operation the data that gather.

2. intelligent irrigation according to claim 1 system, it is characterized in that: the transmission means of described step (2) is whole ZigBee transmission, for this variation of farmland water content situation slowly, the ZigBee wireless transmission of low rate can meet the demands fully.

3. intelligent irrigation according to claim 1 system, it is characterized in that: described step (3) is summed up on previous experiences and is constantly revised in the selection of the weights that utilize data fusion.

4. intelligent irrigation according to claim 1 system, is characterized in that: interface easy operating and the management of described step (4) hommization.

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