Information and communication technologies for irrigation management

Transcription

1 Information and communication technologies for irrigation management Daniel Boffety a, Jean-Pierre Chanet a, Géraldine André a, Frédéric Vigier a a Cemagref, 24 Av. des Landais, BP 50085, Aubière Cedex France, daniel.boffety@cemagref.fr, jean-pierre.chanet@cemagref.fr, geraldine.andre@cemagref.fr, frederic.vigier@cemagref.fr Abstract Nowadays, water resource management is more and more important. Modern agriculture is a large-scale water consumer, which must adjust as well as possible its consumption in adequacy with its needs, while preserving the natural resources and the quality of the productions. Information and Communication Technologies (ICT) offer solutions to make possible a finer approach of the irrigation of the crop by facilitating the work of the farmers. The work exposed in this article shows the contribution of ICT to manage irrigation pivots in a farm. The technologies used are ad hoc wireless networks and Web technologies. The farmer can, via the Internet, ensure the monitoring and the remote control of the irrigation equipment, in a more precise way and in conformance with the crop's requirements. Key words: Information and Communication Technologies, irrigation pivots, wireless ad hoc networks, Web technologies. 1 Introduction Today, ICT are very useful for agriculture. They allow to ensure the traceability of products and practices, and also improve farmer's working conditions increasing the effectiveness of equipments. ICT also allow a better natural resources management such as water through the irrigation monitoring of the cultures. Irrigation is automated since a long time, but wireless networks allow to consider new and more powerful solutions, such as automatic integration of the crops water needs and the remote management for the irrigation devices like pivots systems. Moreover, Internet is now even accessible in rural areas by combination from various techniques. Telecommunications satellite systems with terrestrial Wi-Fi networks were tested for the installation of the broad band access in rural areas within the framework of the European project TWISTER 1 (Terrestrial Wireless Infrastructure integrated with Satellite Telecommunications for E-Rural). The objective of our work is to use these various solutions in order to develop new remote applications for irrigation. This is done by the combination of ad hoc networks and satellite Internet access. 1 TWISTER: Terrestrial Wireless Infrastructure integrated with Satellite Telecommunications for E-Rural applications 6th Framework Program R&D project Coordinator: EADS ASTRIUM SAS Partners: Aramiska-Netherlands, Eutelsat SA-France, Centre National D' Etudes Spatiales-France, Cemagref-France, Nera Broadband Satellite-Norway, Politechnika Warszawska-Poland, University of Malta-Malta, Diputacion Provincial de Zaragoza- Spain, Aneto-France, ICS-FORTH-Greece, Picopoint B.V-Netherlands

2 2 Application for the irrigation management In this project, the four irrigation pivots of a farm in Allier department in France were transformed into Wi-Fi relays with the objective to be able to send and receive information. In fact these relays are the nodes of an ad hoc network using the OLSR routing protocol. They can relay the information coming from other nodes. This technique of ad hoc networks allows to extend the Wi-Fi cover. By means of this network, the pivots are connected to the farm which is even connected to Internet. The Fig. 1 shows this ad hoc network on this farm. Laptop Pivot 3 Satellite Pivot 4 Satellite Box Parabolic Antena Pivot 2 Router Wi-Fi / Lan Farm Antenna Farm Computer Pivot 1 Laptop PHP Server Application Fig 1: Diagram of the farm ad hoc network 2.1 The irrigation pivot like Wi-Fi relay Each pivot system is equipped with an antenna connected with an electronic Wi-Fi unit which makes it possible to control its moves. Two directional antennas equip the pivots 1 and 3. The pivots 2 and 4 are equipped with omnidirectional antennas (see Fig. 2). A third omnidirectional antenna is connected to a Internet Wi-Fi router installed at the farm house. These five Wi-Fi points constitute the fixed wireless network. An electronic unit is made with a PIC 16F873 microcontroller card and a b router. Each irrigation pivot system behaves like a client and is connected to a Web server installed at the farm. This server stores the positions of each irrigation pivots and sends the instructions entered via a Web interface. The instructions are sent to the pivots by a message frame with different information like the rotation direction, the watering duration, the rotation speed and the angular coordinates of the sprinkled area. Fig 2: Pivots Wi-Fi relays with directional and omnidirectional antennas

3 2.2 Electromechanical and Wi-Fi equipment Each Wi-Fi unit is made with a Wi-Fi Linksys WRT54G router card configured with the OLSR routing protocol, with a PIC 16F873 microcontroller electronic card and with a Acksys Cometh module (see Fig. 3). The microcontroller is directly programmable on its electronic card by a JTAG connector. The rotation direction and the angular position of each pivot are given by two detectors connected to this electronic card. The messages obtained from the electronic card are transmitted by a RS232 serial communication port to the Acksys Cometh module which transforms them into Ethernet messages for the Wi-Fi router card. This electronic connection allows to send the configuration messages of the pivots, their remote control, the transmission of the angular positions and of the rotation direction of each pivot. Each pivot message with its identifier are sent regularly in the form of an UDP broadcast frame on the network. Fig 3: Electronic unit with a Wi-Fi router A small electronic relay card is connected to the principal electric box of the pivots. The remote control from each pivot is possible in full safety by preserving all the monitoring and safety functionalities, in particularly the emergency stop key function, the watering limit area switches and the water valve security. This electronic card allows to ensure an electric adaptation and protection between the various electric levels of this control. The angular position and the rotation direction of each pivot are given by a sensor shaped like an angular sector with metallic studs and two electromechanical detectors. Fixed on the rotation part of the pivot, at each passage of a stud, each angular sector activates the electromechanical detector of angle. The second electromechanical detector gives the rotation direction. The spacing between two consecutive studs corresponds to a swing of 10 degrees angle. 2.3 Main functionalities of the device The remote programming function and the remote control of each pivot irrigation system are possible. Different choices of the pivot irrigation system configuration are possible, clockwise or anti-clockwise direction, rotation speed in the limit of a maximum speed of 119m/h defined by the maker, watering or not watering mode and the value of the watering angular sector. These options are validate by selecting rotation direction, by adjusting the electric motors power supply control of the different pivot sections and by activating the electromagnetic water valve of the pivot. Different safety functions are realised by the angular measurement of the positions of each pivot irrigation system, for example, to avoid any collision between two pivots irrigation system which move on the same working area or to respect the watering field areas near a road or a farm-road. This network allows the various equipments to interact with each other and to manage all of them without sending information to the network supervisor. The displacement of the pivot irrigation system without water can be possible from one Wi-Fi PDA or a Smartphone. The farmer can remote control the irrigation pivot system from his tractor to work on a free field.

4 2.4 Information display and communication on the established network For the visualization of the pivots irrigation system positions on the field, a specific supervision application was developed and installed on the farm desktop PC (see Fig. 4). This Web application remotely consult was developed in PHP language in relation with the free cartographic server MapServer. The messages reception of each electronic unit allows to display the position of each pivot irrigation system every second under Mapserver. The different positions of each pivot irrigation system are displayed by angular step of 10. A remote visualization is also possible by means of a PC or a PDA equipped with a Wi-Fi card and an Internet navigator. Fig 4: Monitoring display application and configuration window A configuration graphic interface makes it possible to interact with the electronic units of each irrigation pivots system by means of the Wi-Fi network and a communication protocol. Five identifiers allow to send the information on the network to identify each element of the network and in particularly the four pivots and the computer of the farm office. A sixth identifier is used for all elements of the network. Several information are exchanged on the network: - Position message of the pivot, management of the watering area, progression of the pivots, - Configuration message of the pivot activity, - Information message returned by the indicators of the electrical equipment box, - Protocol messages, acknowledgement of delivery and error message to the reception, - Initialization message for the installation of the system, - Emergency stop message, - Enable/disable message of the remote control system (SCD),

5 For these information exchanges, seven main types of messages with seven identifiers are used. All the messages have "#"character like indicator of start of message, and one like indicator of end of message. The information contained in the same message are separated by the character ",". On the network, with the routing messages of the OLSR routing protocol in according to the needs, these main types of messages used are: - pivot position message: "# recipient transmitter, P, This message is sent by each pivot for all the network. It contains the information of the pivot angular position, preceded by the code message "P": - configuration message: "# recipient transmitter, counter of frame, code message, sequence number, final position, watering, rotation direction, speed@ checksum". When the user defined a sequence of displacement of a pivot, a message of configuration is sent to it. This message contains the values of the various variables necessary to the configuration of a sequence: Code message: S Number of sequence: N Final position: N (X 10 ) Watering: 0 or 1 Feel rotation: 0 or 1 Speed: N. In this frame, a counter of frame, incremented by the transmitter, is used by the receiver to transmit the acknowledgement of delivery and to check the coherence between the sent data and the received data. A checksum is calculated for this message to check the possible errors. The checksum is placed after the end character of frame to avoid confusions if ever the checksum had the same value as the character "@". The end of the configuration of the sequences will be done by the sending of a configuration sequence message with a null speed variable. No sequence can be carried out as long as a message indicating the end of the configuration will not have been delivered. The end configuration message can be : "# recipient transmitter, counter of frame, code message, sequence number, final position, watering, rotation direction, checksum". - Acknowledgement of delivery message: "# recipient transmitter, number of frame, When the microcontroller receives a message of configuration without error, it returns with the number of the frame of configuration, an acknowledgement of delivery with message OK. If there is another configured sequence it will be sent to him only if the microcontroller shows reception of the preceding sequence. - Error message: "# recipient transmitter, number of frame, If the microcontroller receives a message of configuration and that after checking of the checksum it notes an error, it will return an error message to the application with the number of the frame concerned so that it is sent to him again. - Initialization message: "# recipient transmitter, The initialization message is in theory only used at the first starting of the system of remote control. It will use to initialize the pivot position at 0. Thus when the microcontroller receives this message, its position is forced to zero. The code message used is the character "I". - Emergency Stop message: "# recipient transmitter, The emergency stop message stops the pivot remote control. After an emergency stop, a new pivot configuration sequences is necessary. The code of emergency stop message is the character "T". - Enable of the remote control system message: "# recipient transmitter, This message permits to choose which system will be use, the original electric box or the remote control system (SCD). The code message used here is the character "D".

6 3 Conclusion An agricultural ad hoc Wi-Fi network fixed was set up on pivots irrigation system starting from electronic routers Linksys WRT54G cards. These Wi-Fi modules configured with OLSR protocol constitute the basic elements of this ad hoc Wi-Fi network. The electronic card developed starting from a microcontroller PIC 16F873 makes it possible to follow and to remote all the pivots starting from a dataprocessing interface developed in PHP language with the assistance of the free cartographic server MapServer and a graphic application installed on the farm PC. Also this station permits to diffuse the pivots positions on Internet. The remote monitoring irrigation can be realised with a computer connected to Internet. These applications can be directly used starting from a PDA Wi-Fi or Smartphone to make it possible to the farmer to follow and to control these pivots in any point of its farm. A mobile or fixes Wi- Fi element disseminating information could be easily attached to this network. An agricultural equipment working on a field will be able to communicate towards the fixed network, a remote recording of information is then possible. The next stage of our work is the integration in the network of sensors like water sensor to develop a complete control of the irrigation management which takes into account the real water crops's requirements. Of course the sensors will be wireless sensors sending their data via the network to the server of the farm. This free communication solution of pivot irrigation system remote control has an undeniable advantage compared to the Global System for Mobile communication solutions (GSM). The replacement of the electronic microcontroller card by a programmable logic controller with Ethernet modules will simplify the application and will adapt it at all the situations. 5 References E. Barbe, D. Boffety, J. P. Chanet, G. André, V. Abt and F. Vigier, Implementation of mixed communication solutions, satellite and Wi-Fi, applied to agriculture. Experiments conducted in the French agricultural sector within the framework of the European project Twister, 4th World Congress on Computers in Agriculture and Natural Resources (WCCA 2006), Orlando, USA, July 2006, 2006, pp J. P. Chanet, Wireless technology and information system for traceability, Workshop on Farm Advisory System and Farm Level Traceability, Barza di Ispra, ITA 02/04 October 2006 ;, 2006, pp. 16. J. P. Chanet, D. Boffety, G. André and F. Vigier, Ad Hoc Network for Agriculture: Irrigation Management, XVI CIGR World Congress, Bonn, Germany, 2006, pp. 6. T. Clausen and P. Jacquet, Optimized Link State Routing Protocol (OLSR), RFC 3626, IETF - MANET Working Group, 75p., H. J. Meyer, C. Rusch and U. Hoppe, Self-configurating, mobile networks in the area of agriculture, XVI CIGR World Congress, Bonn, Germany, 2006, pp. 6. P. Minet, Réseaux mobiles ad hoc et réseaux de capteurs sans fil, Hermes- Lavoisier, 2006, pp E. Quendler, I. Kristler, A. Pohl, T. Buchegger, B. Jakoby, S. C. Niernsee and J. Boxberger, Driver Assistant System LISA, XVI CIGR World Congress, Bonn, Germany, 2006, pp. 21. G. Steinberger, M. Rothmund and H. Auernhammer, Agricultural Process Data Service (APDS), XVI CIGR World Congress, Bonn, Germany, 2006, pp. 6. G. Vellidis, M. Tucker and C. Bednarz, A Real-time Smart Sensor array for Scheduling Irrigation, Automation Technology for Off-Road Equipment, Bonn, Germany, 2006, pp