The conception and the implementation of a control system for
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1. both electronic boards were nearly completed the only two things left to do were soldering the headers to the WiFly shield and creating a reset button with a correspond ing LED connecting pins for servos and photocells and casing for the antenna Until the project was finished all ideas were prepared and tested on the breadboard All the casings were made from 3mm plexi plates Main casing transparent BlackBox black A reset button was added as a safety measure that returns all network settings to default to avoid having to reprogram the mainboard in case the wrong settings were set Second was the software which was also divided into two sections control board and PC A block diagram of control system software is presented in figure 2 loadlibraries define registers variables and structures initialize 1 0 SPI_UARTbridge connect to the network me NO Client Request YES pau gt gt Resetto default Restet NO Photocell value request Clear register buffer Execute Telnet command Post gt gt YES Move servo NO e a cet gt ESs Send data over HTML Check client request Fig 2 Block diagram of control system software After start up and setting up all needed libraries WCS can be set into two modes One when awaiting for a speci fied order and sending back to the PC values measured by the sensors and second where automatic mod2. rity sensors etc not only from on wall panels inside the house but also from a computer or mobile device through a computer network or even remotely via internet SECURITY another place to adopt a designed control system is security This is where many connections be tween motion and data from various sensors are found As we all know the main issue in this application is safety In this case highly encrypted wireless connections between a control system and access points as well as additional en cryption algorithms inside of the control system are needed All of the requirements for this application are fulfilled and new security algorithms can be adopted INDUSTRY CONTROL OVER AUTOMATION OF PRODUCTION PROCESS this is the application where a wide area must be covered by many independent control systems responsible for separate processes In this case adopting a wireless control limits the amount of work for the personnel that directly leads to the reduction of the staff and increases monthly savings Implementation Implementation of the conception presented above was divided into two separate parts The first part contained hardware and a main box Arduino Uno WiFly shield with WCS onboard and the preparation of two servomotors and creating a BlackBox with photocell and servo connect ed to the blind inside The process of creating the hardware aspect of the project was not complicated In the first part the main con trol box
3. In the case of a fluorescent lamp the light intensity pulses causing a reading of 5 points when daylight reading was nearly constant To overcome this effect but not at a huge cost of accuracy the delay at a level of 5 points to servo reaction has been added SPEED CONTROL as this project is based on open source platform many beta or open libraries are available One of those is VarSpeedServo library which allows us to easily control the speed of the connected servos Due to the problems with application that appeared when the project was created we have decided not to use this library Con PRZEGLAD ELEKTROTECHNICZNY ISSN 0033 2097 R 90 NR 2 2014 sidering rapid development of libraries it will be a very valu able asset in future modification of WCS ELECTRIC DISCHARGE another advantage that is really important in application of a control system is safety from electrical discharges When power is supplied from the source and is separate from the power network there is no risk in electrical discharges from the grid This allows us to omit expensive devices which are designed to protect from power network influence RESET two reset buttons are placed on the control system One silver gold acts like turning off and on again It is meant to be used when WCS hangs up The other one black is designed to reset to the default settings of the wireless module Both of them appear to be working without any problems ANTENNA to expand
4. USB and power jack beyond Table 2 HXT900 specification Modulation Analog Torque 4 8V 1 6 kg cm Speed 4 8V 0 12 sec 60 Weight 9 1g Dimensions 21x12x22mm Motor Type Coreless Gear Type Plastic Rotation Support Brushing Rotation Range 90 Pulse Cycle 20ms Pulse Width 450 2450 us Connector Type JR Arduino platform capabilities are also presented in 15 16 17 138 PRZEGL D ELEKTROTECHNICZNY ISSN 0033 2097 R 90 NR 2 2014 Application The main issues of new inventions are the applications History of man kind is full of gadgets created without pur pose that land on shelves never to be used again This is why few examples of implementation of a control system for servomotors via wireless network are presented STAGE LIGHT CONTROL separately controlled stage lights with an ability of preprogrammed movement scenari os or manually controlled The only limitation in the number of lights is determined by the quality of intermediary devices forming a wireless network with an emphasis on DHCP server SPOTLIGHT CONTROL this is very interesting in ad vertising for example Spotlights of appropriate power over the fluorescent surface leaves a luminescent trace that fades away with time Usually advertising boards due to safety issues and better visibility are placed out of people s range With the application of this control system users can control the whole process without the necessity of using h
5. Zygfryd GLOWACZ Jakub WOJCIK AGH University of Science and Technology The conception and the implementation of a control system for servomotors with the application of a wireless network Abstract The aim of this study was to design and create a control system for servomotors with the application of a computer wireless network To achieve this goal 802 119 wireless standard servomotors and open source Arduino platform were used Streszczenie Celem niniejszej pracy by o zaprojektowanie oraz wykonanie systemu sterowania serwomechanizmami z wykorzystaniem bezprze wodowej sieci komputerowej w standardzie 802 11 Do osi gni cia celu zastosowano standard 802 11g serwomechanizmy oraz open source platform Arduino Koncepcja i implementacja systemu sterowania serwomechanizmami z zastosowaniem bezprzewodowej sieci kompu terowej Keywords control system for servomotors wireless network 802 11 arduino S owa kluczowe uk ad sterowania serwomechanizmami sie bezprzewodowa 802 11 arduino doi 10 12915 pe 2014 02 36 Introduction The world runs faster and faster everyday New inven tions appear in every corner of the world This is a fact But the reason cannot be more prosaic Everybody wants to avoid physical activities That is why intelligent buildings become more and more popular cars park themselves or vacuum cleaners operate without our supervision We simp ly do not know in how many different fields we are being replaced
6. by machines That is why this trend of conception of a control system for servomotors with the application of a wireless network is relevant It can also be used in electrical engineering and electronics 1 9 Many different solutions are already available on the market but our purpose was to present a solution that can be adopted not only in the industry or in everyday life but also by academics as interesting laboratory exercise that draws students attention To achieve this goal open source Arduino platform with the adaptation of wireless 802 11 standard 10 as the heart of the control system was cho sen Conception Every project begins with an idea In this case the main idea was to control a servomotor via wireless IEEE 802 11 network 11 To achieve this goal following establishment has been considered Main schematic diagram is presented in figure 1 4 Fig 1 Schematic diagram 1 Every PC contains a WCC Wireless Control Client application For the purpose of the control system one was created with CodeGear Delphi programming language Object language based on Pascal this decision was dictat ed strictly by the experience of the programmer In the fu ture creation of applications on Windows RT Phone An droid Symbian or iOS are possible 2 As 802 11 protocol is basically used in small wireless networks either access point with DHCP server or ad hoc connections between a computer and a control system was requi
7. de 140 servomotors will move by the desired degree as told When entering this mode on servo_1 the photocell automatically goes into auto mode In photocell manual mode users can set searched light intensity inside the box The system will try to adjust the blinds If the value of light intensity needed reaches its max imum value the application will display an appropriate mes sage To control data flow an Advanced checkbox was cre ated When checked both sent and received data will ap pear on the screen The last part of the WCC are settings that are divided into groups Basics where all information needed to estab lish connection are stored Advanced where more network settings like DHCP netmask gateway IP DNS connection password external antenna are placed Observations While conducting tests during the process of projecting and creating a Control System we have noticed a series of pros and cons Some of them are to be revised and some are not Knowing just a few is rather significant LAG as expected in every wireless system visible lag occurs In our case the time from sending a command from WCC software and receiving back confirmation of the com pleted task is about 0 8 seconds When we take into con sideration that this data flows over a WPA2 PSK encrypted network the lag is not that long To decrease this delay optimization of the Arduino code is needed MAX SERVOS for the demonstration of t
8. e is on In this case WCS maintains the light intensity inside the BlackBox on a defined level This mode shows that this control system is not only prepared to set value we send to it but also can supervise the whole operation returning state of the operation to the PC application connected For programming a mainboard environment called Arduino alpha is provided It is an open project written debugged and supported by Massimo Banzi David Vaurtil les Tom Igoe Ginaluca Martino and David Caurtielles It is based on Processing by Casey Reas and Ben Fry As the entire language is mostly based on C this process was limited to recognize syntax distinctive for Arduino board The Learning section of the Arduino project website con tained essential code examples and appeared to be very useful in understanding how all of this works After a few days of playing with Arduino it was time for the WiFly shield Everything went smoother as in this case more technical support was provided The last step was application of the BlackBox To do this the handling of analog input as well as two modes of work PRZEGLAD ELEKTROTECHNICZNY ISSN 0033 2097 R 90 NR 2 2014 139 manual manual control over servos and automatic setting light intensity without controlling over the servo were need ed The entire syntax of Arduino code consists of 4 parts Declarations of libraries variables structures and registers that are needed For exam
9. eavy machinery to reach standard cable control systems In addition with the help of an internet connection control over a network of advertising boards can be remotely con trolled from one place CONNECTION BETWEEN A SENSOR AND A SERVOMOTOR CONTROL everywhere motion is needed as a response to the environmental data collected by the sensors light movement sound acceleration hu midity etc that is out of range for servicing personnel Another advantage is the size area that can be covered by this control system that is limited only by the range of a wireless network In addition the amount of control sys tem in one infrastructure is also nearly limitless EDUCATIONAL LABORATORY EXCERCISE the advantage of this control system is the simplicity of the basics When trying to pass on to students a little bit of new knowledge it is important not to discourage them with very difficult tasks Here we have simple basics that provide instant visible result which motivates new students to the subject as well as capabilities of creating really complicated and advanced projects that demand knowledge and outside the box thinking from students familiar with the subject SMART HOUSES to connect automation of the smart houses to the computer network inside intermediary sys tems are needed This is where the application of a wireless servo control systems comes in The next step in smart housing is to be able to control blinds heating secu
10. he control system we have implemented control over two servomotors In practice the only obstacle that limits number of servos available are pins and power supply In this case 10 13 pins are used by the WiFly shield to communicate with Arduino over SPI The second pin is used by the button and the seventh by the LED This leaves us with a total maximum amount of 6 servomechanisms To increase this amount an additional shield is required STATUS INDICATOR a very useful solution adopted in the WiFly shield is a set of status indicators To control status by taking a look over a control system three onboard LEDs are used PIO4 5 and 6 are highly active and can be connected to external LEDs to provide network connection and data status RANGE in a tested prototype system wireless 802 119 network is used In accordance with the wireless router specifications the device does not exceed a range of 100m indoors or 400m outdoors As always those values are perfect In reality the range did not exceeded 100 meters outdoor in building area PHOTOCELL ACCURACY daylight bulb fluorescent lamp during testing we have noticed that the type of light source from which we are trying to measure light intensity has great influence on the results When we use a bulb the light flickers with such an intensity that despite constant distance and light intensity the reading from the photocell in extreme cases was dropping and rising in range of 15 points
11. ion of eigenvector method and K Nearest Neighbor classifier Archives of Metallurgy and Materials Vol 57 2012 No 2 pp 403 407 4 Glowacz A Glowacz W Diagnostics of Direct Current motor with application of acoustic signals reflection coefficients and K Nearest Neighbor classifier Przeglad Elektrotechniczny Vol 88 2012 No 5a pp 231 233 5 Glowacz A Glowacz W Diagnostics of synchronous motor based on analysis of acoustic signals with application of LPCC and Nearest Mean classifier with cosine distance Archives of Metallurgy and Materials Vol 55 2010 No 2 pp 563 569 6 Glowacz A Glowacz W Diagnostics of dc machine based on sound recognition with application of FFT and Jacquard dis tance Przeglad Elektrotechniczny Vol 86 2010 No 4 pp 292 295 7 Gwozdziewicz M Zawilak J Influence of the rotor construction on the single phase line start permanent magnet synchronous motor performances Przegl d Elektrotechniczny Vol 87 2011 No 11 pp 135 138 8 Sulowicz M Borkowski D Wegiel T Weinreb K Specialized diagnostic system for induction motors Przeglad Elektrotech niczny Vol 86 2010 No 4 pp 285 201 9 Zawilak T Investigation of higher harmonics in a Line Start Permanent Magnet Synchronous Motor Przeglad Elektrotech niczny Vol 84 2008 No 12 pp 122 125 10 802 11 network standards http standards ieee org findstds interps 11 IEEE 802 11 Executive Commi
12. l product this is a worthwhile solution Of course there are plenty of settings not implemented in WCC software We can connect to the Adhoc networks manage tie or UART parameters of use UDP protocol in stead of TCP IP With all of these possibilities highly ad vanced projects are at our fingertips Conclusion In summary this solution implemented to resolve the problem of the wireless control system of the servomotor has met the expectations of the project Furthermore po tential future expansions leaves the solution open for devel opment in many different directions For example in more complicated situations to improve the speed of operations a golden section search algorithm can be implemented Various new sensors like accelerometer pressure temper ature tilt move or hallotron can be connected Many com munication protocols can be implemented xbee gsm gps etc Even bigger projects that would need up to 48 sepa rately controlled servomotors for example are quite possi ble REFERENCES 1 Gieras J F Gieras I A Electrical Energy Utilization Publishing House Adam Marszalek 1998 2 Glowacz A Glowacz A Korohoda P Recognition of Color Thermograms of Synchronous Motor with the Application of Image Cross Section and Linear Perceptron Classifier Prze glad Elektrotechniczny Vol 88 2012 No 10a pp 87 89 3 Glowacz A Diagnostics of induction motor based on analysis of acoustic signals with the applicat
13. ontrol servo with the BlackBox and to man age WCS settings that allows it to connect to the wireless network To achieve this we cannot forget about assigning an appropriate security level Operating principles are very simple At the beginning a user needs to log in After posi tive verification the application tries to connect via telnet protocol with WCS IP address is written in an external setup ini file If the connection was successful control options and settings are available During the writing process the following components were used idTelnet responsible for handling telnet protocol MainMenu simple menu component Timet controlling on time events in application GUI Graphical User Interface is a single standard build with components provided by a programming envi ronment Nothing extraordinary was adopted in this matter just a simple menu with Login Servo and Settings pages that are clear for the user but not necessarily eye pleasing To prevent unwanted people from accessing basic login protection was implemented To level up security a sepa rate algorithm to encode login and password are imple mented Both of them are stored inside setup ini file next to the main execute file When it comes to controlling both servomotors external pins are connected to the servomotor and a photocell is connected inside the BlackBox In each case two modes are available manual and auto In servo manual mo
14. ple External libraries o string h responsible for string commands o servo h set of commands controlling servo mechanisms o EEPROM h allows us to store data in 512 bytes of EEPROM memory where values are stored when the board is turned off SC16IS750 register definitions 14 SPI pin definitions Global variables SC16IS750 communication parameters and struc ture Il void setup activated only once at the start of the board For example Defining servos on proper pins and resetting their position SPI Serial Peripheral Interface to allow communi cation between Arduino Uno board and WiFly Shield Checking in SPI to UART bridge is initializes suc cessfully Ill void loop function which is called over and over again by the Arduino itself This is the place for the main program IV Functions and procedures that we need for the board to serve its purpose from part II or III PC application arrives in the second stage Delphi is the object oriented programming language based on Pascal The version that has been used was 2009 Professional that allows to test all means necessary for the project Permis sion from the official Embarcadero distributor in Poland to use the trial version was granted for this stage For the application to serve its purpose a set of require ments had to be met To describe the whole application we must start with operating principles WCC application has two tasks to c
15. red In this case D Link DSL G684T wireless G54M ADSL2 Modem Router w 4 Port 10 100 Switch capable to test connection WiFi WiFi as well as Ethernet WiFi 3 A control system consists of Arduino Uno mainboard with additional WiFly SparkFun Shield Tab 1 12 13 For this project the control system is called WCS Wireless Control System 4 We have chosen to control two simple 9 gram servomo tors HXT900 by HEXATRONIK Tab 2 The main factors were low cost and relatively good construction 5 As all new inventions without the suggestion of applica tion are rather meaningless to make this project a little bit more alive we decided to add one To do so this Black Box was created Inside a small photocell and one servo motor are hidden The purpose of this box is to maintain previously set light intensity inside The top of the box works like a set of blinds in windows Servomotor controls obscure the blinds while the photocell checks light intensity Table 1 Arduino specification Microcontroller ATmega328 Operating Voltage 5V Input Voltage recommended 7 12V Input Voltage limits 6 20V Digital I O Pins 14 6 PWM Analog Inputs Pins 6 DC Current per I O Pin 40mA DC Current for 3 3V Pin 50mA Flash Memory 32KB ATmega328 0 5KB used by bootloader SRAM 2KB ATmega328 EEPROM 1KB ATmega328 Clock Speed 16MHz Dimensions 2 7x2 1 inches
16. the range of the device an exter nal antenna is provided In the prototype a standard 2dBi D Link antenna is used As standard connection is used there is a possibility to change the antenna to one with greater range HANGING UP unfortunately a prototype device is not flawless During test specific situations WCS tended to hang up and needed to be reset The main issue is insuffi cient power supply When a lack of power appears even for a brief moment communication between the computer software and control system becomes impossible FUTURE IMPLEMENTATION as we can see in the overview of the WiFly shield there are many settings in our Control system The most valuable appears to be power management When using a portable edition of this sort of device power consumption becomes an issue Thanks to sleep mode wake on UART and other available functions we can significantly extend work time on a battery Another not fully implemented feature is the HTTP server As an example an editor is stored inside of the Control System It gives us opportunity to create a separate interface to man age certain settings or just show status data Real time clock within WiFly allows us to use time stamping Thanks to this login session algorithms can be implemented to increase the security level of data sent over HTTP To allow up to date with firmware there is a possibility to deliver over the air updates with the use of the ftp When thinking about fina
17. ttee http www ieee802 0rg 12 Arduino official website http arduino cc 13 WiFly User Manual http www sparkfun com datasheets Wireless WiFi WiFlyGSX um2 pdf 14 SC161S750 Datasheet http www sparkfun com datasheets Components SMD SC161 740_750_760 pdf 15 Arizaga J A de la Calleja J Hernandez R Benietez A Au tomatic control for laboratory sterilization process based on ar duino hardware Electrical Communications and Computers CONIELECOMP 22nd International Conference 27 29 Feb 2012 130 133 16 Georgitzikis V Akribopoulos O Chatzigiannakis 1 Controlling Physical Objects via the Internet using Arduino Platform over 802 15 4 Networks Latin America Transactions IEEE Revista IEEE America Latina Vol 10 2012 Iss 3 17 Sarik J Kymissis l Lab kits using the Arduino prototyping platform Frontiers in Education Conference FIE 2010 IEEE T3C 1 T3C 5 Authors dr hab in Zygfryd G owacz Akademia G rniczo Hutnicza Wy dzia Elektrotechniki Automatyki Informatyki i In ynierii Biome dycznej Katedra Energoelektroniki i Automatyki System w Prze twarzania Energii al Mickiewicza 30 30 059 Krak w E mail qglowacz agh edu pl mgr in Jakub Wojcik Wydzia Elektrotechniki Automatyki Infor matyki i In ynierii Biomedycznej al Mickiewicza 30 30 059 Kra k w E mail jawojcik agh edu pl PRZEGLAD ELEKTROTECHNICZNY ISSN 0033 2097 R 90 NR 2 2014 141
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