Automatizuotų skaitmeninių sistemų mažiems pokyčiams įvertinti tyrimas ; Investigation of digital automatic systems for evaluation of small changes

Rokas

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Rokas KVEDARAS INVESTIGATION OF DIGITAL AUTOMATIC SYSTEMS FOR EVALUATION OF SMALL CHANGES Summary of Doctoral Dissertation Technological Sciences, Electrical Engineering and Electronics (01T) 1211 Vilnius 2005 VILNIUS GEDIMINAS TECHNICAL UNIVERSITY Rokas KVEDARAS INVESTIGATION OF DIGITAL AUTOMATIC SYSTEMS FOR EVALUATION OF SMALL CHANGES Summary of Doctoral Dissertation Technological Sciences, Electrical Engineering and Electronics (01T) Vilnius 2005 Doctoral dissertation was prepared at Vilnius Gediminas Technical University in 2001 – 2005 Scientific Supervisor Prof Dr Habil Romanas MARTAVI ČIUS (Vilnius Gediminas Technical University, Technological Sciences, Electrical Engineering and Electronics – 01T) The Dissertation is being defended at the Council of Scientific Field of Electrical Engineering and Electronics at Vilnius Gediminas Technical University: Chairman Prof Dr Habil Albinas Jonas MARCINKEVI ČIUS (Vilnius Gediminas Technical University, Technological Sciences, Electrical Engineering and Electronics – 01T) Members: Prof Dr Habil Stanislovas ŠTARAS (Vilnius Gediminas Technical University, Technological Sciences, Electrical Engineering and Electronics – 01T) Prof Dr Habil Julius SKUDUTIS (Vilnius Gediminas Technical Univectrical Engineering and Electronics – 01T) Prof Dr Habil Stanislavas SAKALAUSKAS (Vilnius University, Technological

Sujets

• DAC
• SAK

Informations

• Publié par: vilnius_gediminas_technical_university
• Publié le: 01 janvier 2006
• Nombre de lectures: 35

Extrait

 

        Rokas KVEDARAS         INVESTIGATION OF DIGITAL AUTOMATIC SYSTEMS FOR EVALUATION OF SMALL CHANGES   Summary of Doctoral Dissertation Technological Sciences, Electrical Engineering and Electronics (01T)                

 

Vilnius

  2005

1211

 

VILNIUS GEDIMINAS TECHNICAL UNIVERSITY                   Rokas KVEDARAS         INVESTIGATION OF DIGITAL AUTOMATIC SYSTEMS FOR EVALUATION OF SMALL CHANGES       Summary of Doctoral Dissertation Technological Sciences, Electrical Engineering and Electronics (01T)              

 

Vilnius

  2005

 

Doctoral dissertation was prepared at Vilnius Gediminas Technical University in 2001  2005 Scientific Supervisor Prof Dr Habil Romanas MARTAVIČIUS(Vilnius Gediminas Technical University, Technological Sciences, Electrical Engineering and Electronics 01T)  The Dissertation is being defended at the Council of Scientific Field of Electrical Engineering and Electronics at Vilnius Gediminas Technical University:  Chairman Prof Dr Habil Albinas Jonas MARCINKEVIČIUS(Vilnius Gediminas Technical University, Technological Sciences, Electrical Engineering and Electronics  01T)   Members: Prof Dr Habil Stanislovas TARAS (Vilnius Gediminas Technical University, Technological Sciences, Electrical Engineering and Electronics  01T)    Prof Dr Habil Julius SKUDUTIS Gediminas Technical (Vilnius University, Technological Sciences, Electrical Engineering and Electronics  01T) Prof Dr Habil Stanislavas SAKALAUSKAS University, (Vilnius Technological Sciences, Electrical Engineering and Electronics  01T) Prof Dr Habil Algirdas Jonas GALDIKAS (Semiconductor Physics Institute, Physical Sciences, Physics  02P) Opponents: Prof Dr Habil Stasys Vygantas AUGUTIS (Kaunas University of Technology, Technological Sciences, Measurement Engineering  10T) Assoc Prof Dr Jurij NOVICKIJ(Vilnius Gediminas Technical University, Technological Sciences, Electrical Engineering and Electronics  01T) The dissertation will be defended at the public meeting of the Council of Scientific Field of Electrical Engineering and Electronics in the Senate Hall of Vilnius Gediminas Technical University at 2 p. m. on 22 December 2005. Address: Saulėtekio al. 11, LT-10223 Vilnius-40, Lithuania Tel.: [phone]; fax [phone]; e-mail [e-mail] The summary of the doctoral dissertation was distributed on 22 November 2005 A copy of the doctoral dissertation is available for review at the Library of Vilnius Gediminas Technical University (Saulėtekio al. 14, Vilnius, Lithuania) © Rokas Kvedaras, 2005  

 

 

  VILNIAUS GEDIMINO TECHNIKOS UNIVERSITETAS                   Rokas KVEDARAS       AUTOMATIZUOTŲSKAITMENINIŲSISTEMŲ   MAIEMS POKYČIAMSĮVERTINTI TYRIMAS         Daktaro disertacijos santrauka Technologijos mokslai, elektros ir elektronikos ininerija (01T)              

 

Vilnius

2005 

 

Disertacija   rengta   2001      2005   metais   Vilniaus   Gedimino   technikos universitete.   Mokslinis vadovas prof. habil. dr. Romanas MARTAVIČIUS Gedimino (Vilniaus technikos universitetas, technologijos mokslai, elektros ir elektronikos ininerija  01T).   Disertacija ginama Vilniaus Gedimino technikos universiteto Elektros ir elektronikos ininerijos mokslo krypties taryboje: Pirmininkas prof. habil. dr. Albinas Jonas MARCINKEVIČIUS (Vilniaus Gedimino technikos universitetas, technologijos mokslai, elektros ir elektronikos ininerija  01T). Nariai: prof. habil. dr. Stanislovas TARAS Gedimino technikos (Vilniaus universitetas, technologijos mokslai, elektros ir elektronikos ininerija  01T), prof. habil. dr. Julius SKUDUTIS (Vilniaus Gedimino technikos universitetas, technologijos mokslai elektros ir elektronikos ininerija  01T), prof. habil. dr. Stanislavas SAKALAUSKAS universitetas, (Vilniaus technologijos mokslai, elektros ir elektronikos ininerija  01T), prof. habil. dr. Algirdas Jonas GALDIKAS (Puslaidininkių fizikos institutas, fiziniai mokslai, fizika  02P). Oponentai: prof. habil. dr. Stasys Vygantas AUGUTIS technologijos (Kauno universitetas, technologijos mokslai, matavimųininerija  10T), doc. dr. Jurij NOVICKIJ(Vilniaus Gedimino technikos universitetas, technologijos mokslai, elektros ir elektronikos ininerija  01T). Disertacija bus ginama vieame Elektros ir elektronikos ininerijos mokslo krypties tarybos posėdyje 2005 m. gruodio 22 d. 14 val. Vilniaus Gedimino technikos universiteto senato posėdiųsalėje. Adresas: Saulėtekio al. 11, LT-10223 Vilnius-40, Lietuva. Tel.: [phone]; faksas [phone]; el. patas [e-mail] Disertacijos santrauka isiuntinėta 2005 m. lapkričio 22 d. Disertaciją galima periūrėti Vilniaus Gedimino technikos universiteto bibliotekoje (Saulėtekio al. 14, Vilnius, Lietuva) VGTU leidyklos Technika 1211 mokslo literatūros knyga © Rokas Kvedaras, 2005

 

 

  1. General Characteristic of the Dissertation   Topicality of the problem  Progress of the science and technology is increasing need of evaluation of small values of physical quantities and its changes each day. Together with increasing amount of data to be transmitted and evaluated, the need to investigate new or to improve knowledge over existing physical laws and to monitor multiple points of different systems and constructions in real-time to identify unique states of these systems and constructions it is needed to gain comprehensive monitoring and evaluation data which has to be more comprehensive and accurate to meet the needs of the modern science and technologies. The physical quantities in modern automated electronic systems are changed to electrical values for easy automation of the monitoring and evaluation process and digital processing of the results. The processing results are provided to system operator in numeric, graphical or other formats or in case physical model is applied it is possible to provide final conclusion on the unique state of the object under investigation.  Despite of the newest technology trends and new possibilities to decrease costs of the mass electronic production there are still the situations when standard solutions that are used for a long time already are not providing necessary accuracy or, scaling these solutions to the necessary extent those are becoming too complex and expensive. For this reason it is necessary to develop new methods of evaluation of physical parameters or find the ways to develop existing methods in order to increase accuracy and number of channels and at the same time gain low initial investments and support costs and gain high return on investments and low total cost of ownership. Increasing need of evaluation and identification of small changes of physical parameters and spreading of such a technologies from laboratory environment to industry and services, it is necessary critically review technologies and methods used in these fields for many years and to define necessary changes in order to gain simplicity of the use, decrease of the investments and operational costs and to gain characteristics not lower than those used in classic systems. In this doctoral dissertation problems of multipoint and multichannel evaluation of small parameter changes are investigated simultaneously solving problems for reliable evaluations and system operational and manufacturing simplicity and thus low initial investments and operational costs. Two specific systems aimed to define unique state (quality) of the object under test are chosen for investigation. Despite of different parameters of which small parameter changes are to be evaluated in these systems the problems and

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solution strategies solved in both of these systems are depending to the same problem of electrical and electronic engineering science. The first system under investigation is used to identify unique states of different constructions. The system is based on the strain gauges which are attached to the construction under testing and changing length of the gauges in case construction points are under deformation. The change of the length is transformed to the very small change of the gauge resistance which should be evaluated and recalculated to the actual change of the length of the construction at the point of the gauge. Typical systems used for solving this problem is rather complex and therefore these are quite expensive. Most of these systems are not providing enough evaluation accuracy when used in field conditions. Most of the systems are built around unbalanced resistive Wheatstone bridge. There are systems using different methods of deformation evaluation but they are quite expensive and are not used widely for long term multipoint investigations. The second system under investigation is used to automatically identify dynamic parameters of integrated circuits and digital-to-analog converters (DAC). It is used for analysing quality level and class of the produced integrated circuits. There are several parameters to be investigated  the propagation delay time and the settling time. Time of the propagation delay of the fast integrated circuits is in the range of 200 ps. To evaluate settling times of the DACs it is necessary to evaluate very small delay times while the signal amplitude is changing in very small interval of 1 least significant byte (LSB). For instance for 12-bit DAC 1 LSB is only 0,025 % of the total DAC output range and for 16-bit it is only 0,0015 %. For modern high-speed DACs settling times are in the range of tens nanoseconds. Therefore the circuit quality evaluation is dependant on the evaluation of two small parameter changes  the time and the amplitude. Dynamic parameters of the circuits are investigated by scientists of Vilnius Gediminas Technical University. These works are the base for further investigations and development provided in this doctoral dissertation. Nevertheless the problems to be solved are very much the same as for construction state investigation systems: existing methods are not providing enough quality for investigation of multichannel ICs and the systems for such evaluation are too complex and expensive.   Aim and tasks of the work.The aim of the work is to develop methods for evaluation of multichannel small changes of resistance and dynamic parameters of circuits, analyse characteristics efficiency and application possibilities of the methods developed. In order to achieve the aim such problems are solved:

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1. The Wheatstone bridge with automatic digital balancing method using DAC R-2R matrix for evaluation of small resistance changes is developed and investigated. 2.   The measures to increase the quality for evaluation of small changes are investigated. 3.   The capabilities of multichannel systems using balanced Wheatstone bridge for evaluation of small resistance changes are investigated.  4.   The new structure of construction state identification system is proposed. 5.   The multichannel sampling converters are developed and investigated and choosing the best ones. 6.   The methods to increase the quality of dynamic parameters evaluation results based on digital signal processing are investigated.  7.   The new structure of the device for multichannel dynamic parameters evaluation based on research results is proposed. 8.   The basic results are proved by experiments.   Scientific novelty and practical value.In this dissertation new method for implementation of multichannel construction state identification systems based on resistive strain gauges such as acceleration, deformation, force and other gauges where small resistance change is the parameter to be evaluated is proposed. The dissertation author proposed for Wheatstone bridge new automatically digitally balanced method using R-2R DAC. This method and implemented digital signal and result processing enables evaluate for ensuring very small resistance changes and simplify multichannel system. New methods for automatic multichannel evaluation of dynamic parameters of circuits based on multichannel compensating sampling converters are developed and investigated. Digital signal processing method for evaluation of required dynamic parameters of high-speed multi-bit DACs is proposed and investigated.  New method for evaluation of automatic multichannel IC dynamic parameters guarantee simpler and lower price of system implementation, ensuring smaller device dimensions higher reliability and quality of results. The investigation results and the similarities of the proposed methods for different systems are enabling to apply these methods for existing or newly created systems used for evaluation of other small changes parameters.  

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Methodology of research. In this doctoral dissertation analytical, digital modelling and experimental investigation methods are used. Methods of small resistance change evaluation is analysed analytically, analysis of construction identification methods using alternating current Wheatstone resistance bridge is done by digital modelling using MatLab software package, analytical results are approved by experimental investigations. Multichannel sampling converters are investigated using analytic, digital modelling using Electronic Workbench and LabView software packages methods and experimental investigations.   Defended propositions   •   The method for automatic digital balancing of Wheatstone bridge for evaluation of resistance small changes and methods for improvement of evaluation results reliability. •   The structures of automatic digital systems for construction state investigations and monitoring. •   converter for evaluation of dynamic parameters ofMultichannel sampling circuits. •   The structures of multichannel sampling systems for evaluation of dynamic circuits parameters and digital methods for improvement of evaluation results reliability. The scope of the scientific work. scientific work consists of the The general characteristic of the dissertation, 4 chapters, conclusions, list of literature, list of publications and addenda. The total scope of the dissertation  129 pages, 65 pictures, 1 table and 8 addendums with total 26 pages.   2. The content of the dissertation In chapter 1general characteristics of the problem of evaluation of small changes and two systems chosen for investigations are described. In this chapter existing construction state identification systems, its theory and trends are reviewed. Evaluation of small resistance changes by using unbalanced Wheatstone bridges is done. Analysis and experimental investigation of classic strain evaluation systems performed determining the disadvantages. Systems of evaluation of dynamic parameters of circuits are reviewed highlighting disadvantages. At the end of the chapter the aim of the work and the tasks are formulated.  In chapter 2 analysisof the method for evaluation of small resistance  changes by using automatically digitally balanced Wheatstone bridge using R- 2R DAC created by author. General structure of the method is provided in Fig 1. It is established that proposed method allows to avoid multiple

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disadvantages that are typical to the classic system. The main advantages of this method are: a.   Evaluation results are not influenced by the stability and value of the power supply voltage of the Wheatstone bridge: R=R 1 =R 2 R 3 R 4 2 N+2 n R IN , (1) n x R 4 R IN   where n  number of DAC bits,R IN resistance of DAC input (resistance R-2R matrix elements),N decimal DAC control code.   Bridge power supply     U          U +   m th gauge pair R 1   R   2   DA1 Controlle DA2       >    ∞ = =   U 0         Balance   Control and evaluation data     Ba    R 3   R 4   R C   gnicnall de co       Code controlled resistor

  Fig 1.Functional scheme of the method for evaluation of small resistance changes by using automatically digitally balanced Wheatstone bridge with R-2R DAC   b.   Feedback system is regulating itself and therefore reducing influence of external noise to evaluation results. c.   is not influenced by length and resistance of the gaugeSystem connecting wires and therefore can be easily used as multichannel system by multiplexing gauges using low resistance switches. Analysis has shown that this method can be used for monitoring tasks with resolution up to 2 8 . Further increase of resolution is possible only by taking measures to reduce external influence to the evaluation results. It is established that main causes for inaccuracies are:

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1. Zero drift of the operational amplifier. 2.   Higher resolution leads to lower balancing voltage which is influenced by noise and bridge balance point can not be established. Methods of reducing these influences are analysed. It is shown that the resolution can be increased applying these methods: Zero drifts are reduced with: •   Operational amplifiers for alternating voltage: usage of alternating voltage power supply for Wheatstone bridge and amplifiers with signal modulation. •   Compensate drifts: usage of duplicate operational amplifier and known reference evaluation just before evaluation of gauges. Noises with lagging phases are reduced by: •   Usage of digital filters; •   Usage of hardware filtering; •   Averaging of evaluation results. It is established that applying these methods in parallel it is possible to gain resolutions up to 2 14 and therefore gain 0,024 % - 0,006 % accuracy level of evaluation of small resistance changes. In order to gain necessary system flexibility and implement all the methods it is proposed to use Digital Signal processors as a system controller. MatLab tool is used to investigate and define necessary signal filtering digital modelling. The spectrum of the signal of Wheatstone bridge output during balancing and the results of the digital modelling of the filters are shown in Fig 2. Structures of systems of the small changes for resistance evaluation are proposed. Different systems for monitoring and for laboratory purposes are developed. Structure of the system for laboratory investigations with resolution of 2 12 is shown in Fig 3. In chapter 3the problems for evaluation of very short time intervals and dynamic parameters are solved. It is established that multichannel sampling converters has to be developed in order to evaluate propagation delay times for high-speed logic ICs and settling time of high-speed high-bit DACs. Multichannel sampling converter with multiplexer on output is investigated and disadvantages are established. The main disadvantage of such type of converter is that each channel is using energy of sampling pulse and when the number of channels is increased to 610 the energy of the sampling pulse is not enough for normal work of the converters. Converter with multiplexer on input is developed and investigated (Fig 4) to improve characteristics and to reduce physical space of the multichannel converter.  

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