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Informacje o czasopiśmie
Format
Czasopismo
eISSN
1178-5608
Pierwsze wydanie
01 Jan 2008
Częstotliwość wydawania
1 raz w roku
Języki
Angielski

Wyszukiwanie

Tom 6 (2013): Zeszyt 3 (January 2013)

Informacje o czasopiśmie
Format
Czasopismo
eISSN
1178-5608
Pierwsze wydanie
01 Jan 2008
Częstotliwość wydawania
1 raz w roku
Języki
Angielski

Wyszukiwanie

25 Artykułów
access type Otwarty dostęp

LT-PAM: A Ranging Method Using Dual Frequency Optical Signals

Data publikacji: 05 Jun 2013
Zakres stron: 791 - 809

Abstrakt

Abstract

This paper describes a new ranging technique using optical signals. The proposed technique is called LT-PAM (Long-Term Phase Accordance Method), and it has been extended from our own ranging technique called Phase Accordance Method (PAM). LT-PAM transmits multiple sync patterns composed of two sinusoidal waves with different frequencies. Unlike chirp modulation techniques, LT- PAM transmits the two waves simultaneously and thus enables the shortening of measurement time. We have conducted experiments using two types of light sources, collimated and diffused light. The experimental results indicated that the proposed method showed a moderate level of accuracy by adjusting the measurement time. For example, LT-PAM using a light emitting diode transmitting multiple sync patterns lasting 4 ms achieved 19.5 mm standard deviation in a measurement ranging 1500 mm. We also describe the theoretical analyses related to the proposed technique and discuss possible improvements by comparing theoretical and experimental results.

Index terms

  • Optical distance measurement
  • signal processing
  • Long-Term Phase Accordance Method (LT- PAM)
  • time-of-flight (TOF)
access type Otwarty dostęp

Object Handling Precision Using Mouse-like Haptic Display Generating Tactile and Force Sensation

Data publikacji: 05 Jun 2013
Zakres stron: 810 - 832

Abstrakt

Abstract

This paper presents development of new haptic display capable of stimulating the muscles and tendons of the forearms as well as the tactile receptors in the fingers as a new approach for virtual reality device. Investigation of simultaneous presentation of both tactile and force effects are conducted and presented in this paper. The haptic display consists of a tactile display with a 4-by-12 array of stimulus pins driven by micro-actuators and an articulated manipulator. The display’s handle was constructed replicating a conventional PC mouse so that anyone could comfortably use it without special training or operation knowledge. Vertical movement of the virtual tactile pad in the virtual world is controlled in proportion to the compressive force applied on the display pad. This makes it possible to reduce the operator’s energy consumption during manipulation in 3D-space. Operators can now work in 3D-space in spite of their manipulations actually being done in 2.5D-space. Evaluation experiments were performed using the display, in both force-only mode and combined-mode (force + tactile) to verify its presentation capability. In the experiments, subjects tried to assemble virtual blocks in a line. Experimental results shows that the display combining tactile and force sensations provide higher accuracy in a precise virtual assembly task compared to the force-only display because the proposed display provides relative motion between the hands and the blocks.

Index terms

  • Haptic device
  • virtual reality
  • 2.5D-display
  • tactile sensation
  • objects handling
access type Otwarty dostęp

Auto-Adaptive Control of a One-Joint Arm Direct Driven by Antagonistic Shape Memory Alloy

Data publikacji: 05 Jun 2013
Zakres stron: 833 - 849

Abstrakt

Abstract

This paper pursues a promising approach to obtain strain feedback based angular motion control of a manipulator for any robotic application. The proposed single degree of freedom manipulator uses antagonistic shape memory alloy (SMA) actuated wires. Antagonistic SMA actuated structures employ opposing pairs of one-way SMA actuators to create systems capable of a fully reversible response. A self-tuning PID type fuzzy (auto adaptive) based control scheme is designed and implemented experimentally. The controller is designed based on the model estimated by using system identification technique. Experimental and simulation results show that antagonistic SMA actuator in combination with the controller can track any input trajectory signal with high accuracy motion control and is suitable for various control applications.

Index terms

  • Shape Memory Alloy
  • Antagonistic Angular Motion Control
  • One-Joint Arm Manipulator
  • Self-tuning Fuzzy PID
access type Otwarty dostęp

Analysis and Experimental Study of Optimal Soil Moisture Sensor Probe Length

Data publikacji: 05 Jun 2013
Zakres stron: 849 - 866

Abstrakt

Abstract

two parallel needle moisture sensors has been widely used in Soil moisture detection equipment, for example, frequency domain (FD), time domain reflectometry (TDR) and standing wave ratio (SWR) measurement. The design of probe’s port impedance is key technology parameters to soil moisture sensor. In this study, according to the relationships between the length and impedance characteristics of terminal open and closed state probe were presented based on two-pin probe structure of parallel resistance model. The best probe structure was simulated by high frequency structure simulator software HFSS, which based on Maxwell’s equations and finite element method. According to experiment of soil water content by organic solution, the theoretical analysis of the best structure of probe was further validated.

Index terms

  • soil water content
  • sensor
  • length of probe
  • impedance
access type Otwarty dostęp

The Reseach on Wireless Sensor Network for Landslide Monitoring

Data publikacji: 05 Jun 2013
Zakres stron: 867 - 887

Abstrakt

Abstract

The paper mainly discusses design and implementation of key functions such as transceiver unit, MCU control unit, Data acquisition module and Background monitoring unit. Furthermore, the corresponding software platform is implemented according to hardware architecture. Finally the solution is applied into Loess landslide at Luoshan County in China. The experimental results show that bit error rate remains between at 10-5~ 10-6. This range coincides with communication standards of wireless sensor network. Furthermore, collected data are proved to be consistent with natural phenomenon. Compared with traditional monitoring method, the new method has better advantages.

Index terms

  • Wireless sensor network
  • landslide monitoring
  • landslide pre-warning
  • data acquisition
  • bit error rate
access type Otwarty dostęp

Lossless Electrocardiogram Compression Technique and GSM Based Tele-Cardiology Application

Data publikacji: 05 Jun 2013
Zakres stron: 888 - 909

Abstrakt

Abstract

Software based efficient lossless Electrocardiogram compression and transmission scheme is proposed here. The algorithm has been tested to various ECG data taken from PTB Diagnostic ECG Database. The compression scheme is such that it outputs only ASCII characters. These characters are transmitted using Global System for Mobile Communication based Short Message Service system and at the receiving end original ECG signal is brought back using the reverse logic of compression. It is observed that the proposed algorithm offers a moderate to high compression ratio (7.18) without any alteration of clinical information (PRD = 0.023%) with an excellent Quality Score (312.17).

Index terms

  • Sign Byte
  • Amplification
  • Grouping
  • ASCII Character
  • SMS
access type Otwarty dostęp

A Novel Tri-Factor Mutual Authentication with Biometrics for Wireless Body Sensor Networks in Healthcare Applications

Data publikacji: 05 Jun 2013
Zakres stron: 910 - 931

Abstrakt

Abstract

User authentication, as a fundamental security protocol, has been addressed with more concerns recently. Unlike normal authentication processes invoked by a user to access the network, biosensors with healthcare applications normally need to be validated automatically, followed by data transmission to the remote server without any explicit request. Hence, implied authentication procedure involved in such application scenarios shall be addressed. In this paper, a novel tri-factor user authentication protocol with mutual access is proposed for the body sensor networks (BSN) in healthcare application. It is demonstrated that the proposed protocol has its advantages over the existing two-factor user authentication schemes.

Index terms

  • BSN
  • Biosensor
  • Mutual Authentication
  • Security
  • Pattern Vector
access type Otwarty dostęp

Wireless Sensor Network Applications in Cold Alpine Area of West China: Experiences and Chanllenges

Data publikacji: 05 Jun 2013
Zakres stron: 932 - 952

Abstrakt

Abstract

Wireless sensor network (WSN) shows unique advantages in cold alpine area comparing with traditional in-situ monitoring approaches. This paper presents two WSN applications in cold alpine area, one in the Hulugou watershed and the other in the Babaohe watershed, both of which are situated in the upper mountainous reach of the Heihe River Basin of West China. Apart from introductions to the two WSN applications and experimental results, experiences learned and challenges met during designing, testing and deployment of WSN are discussed. The paper concludes a promising future of WSN in environment monitoring in cold alpine areas.

Index terms

  • Wireless sensor network (WSN)
  • cold alpine area
  • environment monitoring
  • eco-hydrology
  • Heihe River Basin
access type Otwarty dostęp

Utility Based Data Gathering in Mobile Sensor Network

Data publikacji: 05 Jun 2013
Zakres stron: 953 - 972

Abstrakt

Abstract

Traditional data gathering approaches cannot be applied to Mobile Sensor Network (MSN) due to sparse network density and sensor node mobility. In this paper, we propose a utility based data gathering protocol (UDG). The distance utility is used to indicate the closeness between sensor nodes and the sink node, and the activity utility is used to evaluate the ability of sensor nodes acting as relays. UDG combines the distance utility with the activity utility to make routing decisions. It also presents a buffer management scheme based on the utility. Experimental results show that UDG achieves desirable performance with low delivery overhead.

Index terms

  • Mobile sensor network
  • location prediction
  • order- Markov chain
  • distance
  • activity
  • utility
  • data gathering
access type Otwarty dostęp

A Blind Source Separation Method for Convolved Mixtures by Non-Stationary Vibration Signals

Data publikacji: 05 Jun 2013
Zakres stron: 973 - 992

Abstrakt

Abstract

A simple and feasible of BSS method to separate the convolution mixture of non-stationary vibration signals is present in this paper. The method is carried out by means of two iterative procedures: The first procedure is to estimate the coefficients of the filters. The independence criterion is used and the unknown filters are obtained by a back propagation procedure by means of simplifying the coefficients of filters. The next procedure is to estimate the source vibration signals. The coupled vibration signals are obtained by means of the filters gotten from the former procedure and the estimation sources are obtained through decoupled procedure. Simulation and experiment results show that the method is effective. This improved method can be used to separate convolutive mixtures with non-stationary mechanical vibrations.

Index terms

  • Mechanical Vibration
  • Blind Source Separation
  • Convolutive Mixture
  • Non-stationary
access type Otwarty dostęp

BI-Filtered Forwarding: A Quasi-Optimal Routing Algorithm for Query Delivery in Wireless Sensor Networks

Data publikacji: 05 Jun 2013
Zakres stron: 993 - 1011

Abstrakt

Abstract

A quasi-optimal query propagation algorithm Bi-Filtered Forwarding (BFF) for quickly routing a query throughout a wireless sensor network is proposed in this paper. BFF is implemented in a limited flooding manner for guaranteeing quick query propagation and low message consumption in wireless sensor networks. The experimental results show that in comparison with the flooding algorithm, BFF can greatly reduce the redundant message consumption during the procedure of real time query propagation throughout a wireless sensor network.

Index terms

  • Real time routing
  • distributed query processing
  • query propagation
  • constrained flooding
  • wireless sensor networks
access type Otwarty dostęp

Design And Realization of a UHF RFID Interrogator

Data publikacji: 05 Jun 2013
Zakres stron: 1012 - 1031

Abstrakt

Abstract

RFID is a generic item which uses radio waves to automatically identify objects and people. This paper presents a flexible RFID interrogator system architecture which could support various kinds of RFID standards and realizes a UHF RFID interrogator based on the EPC global C1G2 standard in details. The proposed interrogator system consists of RF analog front end, digital baseband and MAC layer. The system circuit contains a FPGA chip and peripheral circuits. NiosII core as a controller is inserted in FPGA. The proposed FPGA based baseband platform could implement various kinds of RFID standards, and efficiently reduce the design time and development cost.

Index terms

  • RFID
  • interrogator
  • reader
  • UHF
  • EPC C1G2
  • baseband
  • transceiver
access type Otwarty dostęp

An Estimation Algorithm for Missing Data in Wireless Sensor Networks

Data publikacji: 05 Jun 2013
Zakres stron: 1032 - 1053

Abstrakt

Abstract

For estimating the missing data of wireless sensor networks, an estimation algorithm called HD method, which can make use of sensoring space-time correlation of the data, was proposed based on mathematical Hermite and DESM statistical models. The algorithm not only can adaptively adjust the time and space weights, but also can accurately estimate the missing or unavailable data. The experimental results show that the algorithm has good stability and relatively high estimation accuracy.

Index terms

  • Wireless sensor network
  • missing data
  • mathematical model
  • estimation algorithm
  • spacetime correlation
access type Otwarty dostęp

Duty Cycling in Target Monitoring Wireless Sensor Network Systems

Data publikacji: 05 Jun 2013
Zakres stron: 1054 - 1076

Abstrakt

Abstract

Duty cycling is an important method for energy constrained sensor network systems to prolong lifetime. Current research on duty cycling is mainly based on such assumption that all the sensory coverage should be maintained while some nodes are sleeping. However, for the applications of target monitoring, it is not necessary anymore to keep the whole sensory coverage of the sensor network. It only needs to make sure that such kinds of nodes are active which can perceive the activities of the monitored targets. This paper proposes a novel duty cycling design for target monitoring sensor networks, which includes two algorithms - sleep scheduling algorithm and gradient query algorithm based on sleep periods. In the proposed design, most of sensor nodes are sleeping, while still keep the functions of target monitoring and information query in the sensor networks. The performance of our design has been evaluated through both theoretical analysis and simulations, which prove the functionality of the proposed design on the reduction of energy consumption.

Index terms

  • Duty cycling
  • sleep scheduling
  • gradient query
  • target monitoring
  • wireless sensor network systems
access type Otwarty dostęp

Comparative Study of Pressure Wave Mathematical Models for Hp Fuel Pipeline of Ceup at Various Operating Conditions

Data publikacji: 05 Jun 2013
Zakres stron: 1077 - 1101

Abstrakt

Abstract

High pressure (HP) Fuel Pipeline is one of the major components of Combination Electronic Unit Pump (CEUP) fuel injection system which has important role in building up of fuel pressure necessary for fuel injection. Three different 1D mathematical models of damped wave equation (WE) namely linear damped, viscous damped and damped model have been developed in MATLAB to investigate fuel pressure inside HP fuel pipeline of CEUP fuel injection system at various operating conditions of diesel engine. Lab experiments have been conducted to measure the pump side and injector side pressures by using KISTLER 4067 piezoresistive pressure sensors under controlled environment. Each model has been verified by comparing its simulated results with those of experimentally verified AMESim numerical model of CEUP system. Model evaluation statistical techniques like “Root Mean Square Error” (RMSE) and “Index of Agreement” (IA) have been used to quantify the predicted results of each mathematical model at various operating conditions. From analytical and quantitative analysis it has been concluded that viscous damped mathematical model predicts more accurately as compared to rest of models specially at all combinations of cam rotational speeds and cam angles of 700rpm, 1100rpm and 6°CaA, 10°CaA and 14°CaA respectively. Damped mathematical model predictions have been found relatively more precise at cam angles of 6°CaA and cam rotational speeds of 900rpm and 1300rpm. Moreover linear model was accurate at cam rotational speed of 900rpm and cam angle of 14°CaA.

Index terms

  • Wave equation
  • Mathematical model
  • High pressure fuel pipeline
  • Finite difference
  • RMSE
  • IA
access type Otwarty dostęp

The Effects of MOS Layers on Sensing Properties of MOS Photosensor

Data publikacji: 05 Jun 2013
Zakres stron: 1102 - 1110

Abstrakt

Abstract

In this research work, many samples of metal –oxide –silicon photosensors were laboratory prepared by thermal evaporation techniques. Some silicon samples were left in the air for a predefined time for SiO2 to grow naturally, while others were thermally coated with measured thickness of SiO. A number of the samples were coated with nickel while others with aluminum and one sample was coated with indium. Various tests and measurements were conducted; these include transmittance tests with a range of wavelength and for different thicknesses. The ideality factors of the samples and the potential barrier height were calculated from I-V and C-V characteristics. The photogenerated current of the samples were also measured at photoconductive mode under reverse voltage. Quantum efficiency measurement indicated that native oxide samples provided higher quantum efficiency than those thermally deposited samples. Detectivity measurement showed that thermally deposited oxide samples had low detectivity as compared to native oxide samples

Index terms

  • Schottky Barrier Diode
  • Photosensor
  • MOS Photosensor
  • Silicon Photosensor:
access type Otwarty dostęp

A reliable signal conditioning circuit to acquire human biopotentials

Data publikacji: 05 Jun 2013
Zakres stron: 1116 - 1132

Abstrakt

Abstract

It is well known that every human being is a complex system made up of cells, tissues, organs and organ systems that function together to maintain its health. The coordinated physiological processes maintain most of the steady states in an organism, not at a fixed value, but within a narrow, relatively constant range, known as homeostasis [1]. Recently, a non-invasive measurement of human biopotentials has been proposed in order to provide information about the condition of the human system as a whole [2]. In this work, the development of two identical signal conditioning circuits that facilitate the acquisition of the human biopotentials simultaneously from both the hands has been presented. The objective of developing these circuits is to enhance the signal levels of both the measured biopotentials uniformly and faithfully, without distortion. This is expected to enable a more reliable and detailed analysis of the acquired signals in future.

Słowa kluczowe

  • human system
  • bioelectric signals
  • signal conditioning circuit
  • static and dynamic calibration
  • statistical analysis
access type Otwarty dostęp

PLC Based Adaptive Fuzzy PID Speed Control of DC Belt Conveyor System

Data publikacji: 05 Jun 2013
Zakres stron: 1133 - 1152

Abstrakt

Abstract

Conveyor belt system is one of the most common transfer systems used in industry to transfer goods from one point to another in a limited distance. It is used in industries such as the electro- mechanical/mechanical assembly manufacturing to transfer work piece from one station to another or one process to another in food industries. The belt conveyor system discussed in this paper is driven by a DC motor and two speed controllers. The PID speed controller is designed to provide comparison to the main controller which is the Adaptive Fuzzy PID Speed controller. Both controllers are implemented in a real hardware where the algorithm will be written in PLC using SCL language. The experimental result shows that Adaptive Fuzzy PID controller performs better and adapted to the changes in load much faster than the conventional PID controller. This project has also proved that PLC is capable of performing high level control system tasks.

Index terms

  • DC belt conveyor system
  • speed controller
  • adaptive fuzzy PID
  • programmable logic controller
  • structured control language
access type Otwarty dostęp

Dielectric Resonator Antenna as a RFID Tag for Human Identification System in Wrist Watch

Data publikacji: 05 Jun 2013
Zakres stron: 1153 - 1166

Abstrakt

Abstract

Radio Frequency Identification (RFID) has been considered as a time and money-saving solution for a wide variety of applications, such as manufacturing, supply chain management, and inventory control. However, there is a growing need in the RFID community to research and find out the tag with miniature, circular polarized radiation patterns, dual band operation, high radiation efficiency and high bandwidth operations. This paper presents compact radio frequency identification (RFID) tag for human identification system in wrist watch. Dielectric resonator antenna (DRA) with patch is used as an active tag. The proposed antenna is operated on dual frequency bands. Simple microstrip line is used as a feeding mechanism. It is operated at 2.4 GHz and 5.8 GHz frequency band. It has circular polarization radiation patterns. Simulation results are presented on various parametric studies on the RFID tag.

Słowa kluczowe

  • Dielectric Resonator Antenna
  • RFID tag
  • human identification system
access type Otwarty dostęp

A Simplified Model Structure for an Activated Sludge System

Data publikacji: 05 Jun 2013
Zakres stron: 1167 - 1179

Abstrakt

Abstract

Activated sludge system is the essential technology in use for municipal wastewater treatment plant. The system design for pollutants removal, safety analysis and experimentation relied upon an effective, straightforward and reliable model. However, most of the available models are too complex to use for control purposes either practically or via simulation. Therefore, vehement need for a simplistic and efficient model could not be avoided. This paper presents a simplified model structure for an activated sludge system using neuro-fuzzy system. Efficiency, ease of use, effectiveness and fast convergence are some of the alluring qualities of neuro-fuzzy technique. Building a reliable and flexible model requires validation with full scale or experimental data. Therefore, with the use of the full-scale data from the domestic wastewater treatment plant in Malaysia, the validation was achieved. For comparison, auto regressive with exogenous input (ARX) model was used. Simulation studies showed that the proposed method produced promising results, thus revealing the technique is effective and robust in modelling the activated sludge system.

Index terms

  • Model
  • pollutants
  • neuro-fuzzy
  • anfis
  • parameters
access type Otwarty dostęp

Model Based Application Level Middleware for Design of Wireless Smart City

Data publikacji: 05 Jun 2013
Zakres stron: 1180 - 1199

Abstrakt

Abstract

The Wireless Smart City (WSC), an emerging concept in Smart Grid and Internet of Things, has attracted an increasing number of customers and developers - based with its promise of low cost implementation and flexibility. At the same time, the challenges faced with in the field applications hinder the progress of WSC from researches into commercial production. A model based application level auxiliary platform is presented to help the development of WSC. This middleware together with the existing network simulators replace field test during WSC design. The proposed platform reduces engineering cost and increases development efficiency. Network optimization is implemented to provide an automatic design of WSC.

Index terms

  • Smart City
  • Performance Evaluation
  • Optimal Deployment
  • Simulated Annealing
  • Wireless Sensor Network
access type Otwarty dostęp

Multiple Parameter Monitoring System for Landslide

Data publikacji: 05 Jun 2013
Zakres stron: 1200 - 1229

Abstrakt

Abstract

China has complex terrain where landslide happens very frequently, thus leading to serious damages sometimes. So in China much attention is paid to the monitoring of landslide. There are various methods in landslide monitoring all over the world. Bas1200ed on the analysis on previous landslide monitoring instruments, this paper designs a new kind landslide monitoring system, which can monitor three parameters of different depth at a time: internal displacement, internal geotechnical pressure and pore water pressure. The system consists of three parts: mechanical structure, monitoring system and PC software. In this system the data collected by sensors are firstly stored in the SD card, and the user will be able to read the monitoring data at regular intervals instead of monitoring data changing timely, which can save labor, especially at the initial stage of landslide. At last laboratory testing has been done to verify the accuracy of this measuring system and the result satisfies the design requirements.

Index terms

  • Landslide
  • monitoring
  • internal geotechnical pressure
  • pore water pressure
  • internal displacement
access type Otwarty dostęp

Fall Detection and Prevention for the Elderly: A Review of Trends and Challenges

Data publikacji: 05 Jun 2013
Zakres stron: 1230 - 1266

Abstrakt

Abstract

It is of little surprise that falling is often accepted as a natural part of the aging process. In fact, it is the impact rather than the occurrence of falls in the elderly, which is of most concern. Aging people are typically frailer, more unsteady, and have slower reactions, thus are more likely to fall and be injured than younger individuals. Typically, research and industry presented various practical solutions for assisting the elderly and their caregivers against falls via detecting falls and triggering notification alarms calling for help as soon as falls occur in order to diminish fall consequences. Furthermore, fall likelihood prediction systems have been emerged lately based on the manipulation of the medical and behavioral history of elderly patients in order to predict the possibility of falls occurrence. Accordingly, response from caregivers may be triggered prior to most fall occurrences and accordingly prevent falls from taking place. This paper presents an extensive review for the state-of-the- art trends and technologies of fall detection and prevention systems assisting the elderly people and their caregivers. Furthermore, this paper discusses the main challenges, facing elderly fall prevention, along with suggestions for future research directions.

Index terms

  • Fall detection
  • fall prevention
  • elderly monitoring
  • motion sensing
access type Otwarty dostęp

Field Programmable Gate Array Based Embedded System for Non-Invasive Estimation of Hemoglobin in Blood using Photoplethysmography

Data publikacji: 05 Jun 2013
Zakres stron: 1267 - 1282

Abstrakt

Abstract

In this paper, a Field Programmable Gate Array (FPGA) based embedded system has been proposed for non-invasive detection of hemoglobin in blood using photoplethysmography. Photoplethysmography (PPG) is a non-invasive and low-cost optical technique that can be used to detect blood volume changes in the micro-vascular bed of tissue. Our investigations revealed that volume of water present in blood considerably affects the reading of the concentration of blood hemoglobin. In our current work, the proposed device is developed with monitoring of PPG waves at three wavelengths so as to compensate for the error due to absorption of near infrared radiation (NIR) by water in the blood. The device also has been developed to be robust enough to tolerate distortions in the waveform due to motion of the subject. In order to sense the motion of the subject a 3-axis accelerometer has been used and correction is suitably applied to the sensed waveform. As a result, it is possible to measure the concentration of hemoglobin in blood while the subject is on the move.

Index terms

  • Field Programmable Gate Array
  • photoplethysmography
  • non invasive estimation
  • near infra red radiation
access type Otwarty dostęp

Development of a Cardan Mechanism for the Asteroid Lander

Data publikacji: 05 Jun 2013
Zakres stron: 1283 - 1297

Abstrakt

Abstract

It is of great significance for improving the landing stability and adjusting the attitude of equipment base by designing a cardan mechanism in the asteroid lander. In the paper, a cardan mechanism having cushion and attitude adjusting functions is designed for the asteroid lander. The cardan mechanism contains electromagnetic damping, belt transmission and cross-shaft, and it has merits of adjustable damping and bearing large overload. The attitude control system of the cardan mechanism is built by FPGA chip. Kinematics and kinetics of the cardan mechanism are analyzed for attitude control. Complex feedback PD controller is applied to control the attitude of the cardan mechanism as large mass equipment base would influence control performance. This controller contains real time gravity compensation, desired acceleration compensation and velocity feed forward compensation. The experiments show that the cardan mechanism designed in this paper has good performance by adopting Complex feedback PD controller.

Index terms

  • Cardan mechanism
  • kinematics
  • kinetics
  • complex feedback PD controller
  • asteroid lander
25 Artykułów
access type Otwarty dostęp

LT-PAM: A Ranging Method Using Dual Frequency Optical Signals

Data publikacji: 05 Jun 2013
Zakres stron: 791 - 809

Abstrakt

Abstract

This paper describes a new ranging technique using optical signals. The proposed technique is called LT-PAM (Long-Term Phase Accordance Method), and it has been extended from our own ranging technique called Phase Accordance Method (PAM). LT-PAM transmits multiple sync patterns composed of two sinusoidal waves with different frequencies. Unlike chirp modulation techniques, LT- PAM transmits the two waves simultaneously and thus enables the shortening of measurement time. We have conducted experiments using two types of light sources, collimated and diffused light. The experimental results indicated that the proposed method showed a moderate level of accuracy by adjusting the measurement time. For example, LT-PAM using a light emitting diode transmitting multiple sync patterns lasting 4 ms achieved 19.5 mm standard deviation in a measurement ranging 1500 mm. We also describe the theoretical analyses related to the proposed technique and discuss possible improvements by comparing theoretical and experimental results.

Index terms

  • Optical distance measurement
  • signal processing
  • Long-Term Phase Accordance Method (LT- PAM)
  • time-of-flight (TOF)
access type Otwarty dostęp

Object Handling Precision Using Mouse-like Haptic Display Generating Tactile and Force Sensation

Data publikacji: 05 Jun 2013
Zakres stron: 810 - 832

Abstrakt

Abstract

This paper presents development of new haptic display capable of stimulating the muscles and tendons of the forearms as well as the tactile receptors in the fingers as a new approach for virtual reality device. Investigation of simultaneous presentation of both tactile and force effects are conducted and presented in this paper. The haptic display consists of a tactile display with a 4-by-12 array of stimulus pins driven by micro-actuators and an articulated manipulator. The display’s handle was constructed replicating a conventional PC mouse so that anyone could comfortably use it without special training or operation knowledge. Vertical movement of the virtual tactile pad in the virtual world is controlled in proportion to the compressive force applied on the display pad. This makes it possible to reduce the operator’s energy consumption during manipulation in 3D-space. Operators can now work in 3D-space in spite of their manipulations actually being done in 2.5D-space. Evaluation experiments were performed using the display, in both force-only mode and combined-mode (force + tactile) to verify its presentation capability. In the experiments, subjects tried to assemble virtual blocks in a line. Experimental results shows that the display combining tactile and force sensations provide higher accuracy in a precise virtual assembly task compared to the force-only display because the proposed display provides relative motion between the hands and the blocks.

Index terms

  • Haptic device
  • virtual reality
  • 2.5D-display
  • tactile sensation
  • objects handling
access type Otwarty dostęp

Auto-Adaptive Control of a One-Joint Arm Direct Driven by Antagonistic Shape Memory Alloy

Data publikacji: 05 Jun 2013
Zakres stron: 833 - 849

Abstrakt

Abstract

This paper pursues a promising approach to obtain strain feedback based angular motion control of a manipulator for any robotic application. The proposed single degree of freedom manipulator uses antagonistic shape memory alloy (SMA) actuated wires. Antagonistic SMA actuated structures employ opposing pairs of one-way SMA actuators to create systems capable of a fully reversible response. A self-tuning PID type fuzzy (auto adaptive) based control scheme is designed and implemented experimentally. The controller is designed based on the model estimated by using system identification technique. Experimental and simulation results show that antagonistic SMA actuator in combination with the controller can track any input trajectory signal with high accuracy motion control and is suitable for various control applications.

Index terms

  • Shape Memory Alloy
  • Antagonistic Angular Motion Control
  • One-Joint Arm Manipulator
  • Self-tuning Fuzzy PID
access type Otwarty dostęp

Analysis and Experimental Study of Optimal Soil Moisture Sensor Probe Length

Data publikacji: 05 Jun 2013
Zakres stron: 849 - 866

Abstrakt

Abstract

two parallel needle moisture sensors has been widely used in Soil moisture detection equipment, for example, frequency domain (FD), time domain reflectometry (TDR) and standing wave ratio (SWR) measurement. The design of probe’s port impedance is key technology parameters to soil moisture sensor. In this study, according to the relationships between the length and impedance characteristics of terminal open and closed state probe were presented based on two-pin probe structure of parallel resistance model. The best probe structure was simulated by high frequency structure simulator software HFSS, which based on Maxwell’s equations and finite element method. According to experiment of soil water content by organic solution, the theoretical analysis of the best structure of probe was further validated.

Index terms

  • soil water content
  • sensor
  • length of probe
  • impedance
access type Otwarty dostęp

The Reseach on Wireless Sensor Network for Landslide Monitoring

Data publikacji: 05 Jun 2013
Zakres stron: 867 - 887

Abstrakt

Abstract

The paper mainly discusses design and implementation of key functions such as transceiver unit, MCU control unit, Data acquisition module and Background monitoring unit. Furthermore, the corresponding software platform is implemented according to hardware architecture. Finally the solution is applied into Loess landslide at Luoshan County in China. The experimental results show that bit error rate remains between at 10-5~ 10-6. This range coincides with communication standards of wireless sensor network. Furthermore, collected data are proved to be consistent with natural phenomenon. Compared with traditional monitoring method, the new method has better advantages.

Index terms

  • Wireless sensor network
  • landslide monitoring
  • landslide pre-warning
  • data acquisition
  • bit error rate
access type Otwarty dostęp

Lossless Electrocardiogram Compression Technique and GSM Based Tele-Cardiology Application

Data publikacji: 05 Jun 2013
Zakres stron: 888 - 909

Abstrakt

Abstract

Software based efficient lossless Electrocardiogram compression and transmission scheme is proposed here. The algorithm has been tested to various ECG data taken from PTB Diagnostic ECG Database. The compression scheme is such that it outputs only ASCII characters. These characters are transmitted using Global System for Mobile Communication based Short Message Service system and at the receiving end original ECG signal is brought back using the reverse logic of compression. It is observed that the proposed algorithm offers a moderate to high compression ratio (7.18) without any alteration of clinical information (PRD = 0.023%) with an excellent Quality Score (312.17).

Index terms

  • Sign Byte
  • Amplification
  • Grouping
  • ASCII Character
  • SMS
access type Otwarty dostęp

A Novel Tri-Factor Mutual Authentication with Biometrics for Wireless Body Sensor Networks in Healthcare Applications

Data publikacji: 05 Jun 2013
Zakres stron: 910 - 931

Abstrakt

Abstract

User authentication, as a fundamental security protocol, has been addressed with more concerns recently. Unlike normal authentication processes invoked by a user to access the network, biosensors with healthcare applications normally need to be validated automatically, followed by data transmission to the remote server without any explicit request. Hence, implied authentication procedure involved in such application scenarios shall be addressed. In this paper, a novel tri-factor user authentication protocol with mutual access is proposed for the body sensor networks (BSN) in healthcare application. It is demonstrated that the proposed protocol has its advantages over the existing two-factor user authentication schemes.

Index terms

  • BSN
  • Biosensor
  • Mutual Authentication
  • Security
  • Pattern Vector
access type Otwarty dostęp

Wireless Sensor Network Applications in Cold Alpine Area of West China: Experiences and Chanllenges

Data publikacji: 05 Jun 2013
Zakres stron: 932 - 952

Abstrakt

Abstract

Wireless sensor network (WSN) shows unique advantages in cold alpine area comparing with traditional in-situ monitoring approaches. This paper presents two WSN applications in cold alpine area, one in the Hulugou watershed and the other in the Babaohe watershed, both of which are situated in the upper mountainous reach of the Heihe River Basin of West China. Apart from introductions to the two WSN applications and experimental results, experiences learned and challenges met during designing, testing and deployment of WSN are discussed. The paper concludes a promising future of WSN in environment monitoring in cold alpine areas.

Index terms

  • Wireless sensor network (WSN)
  • cold alpine area
  • environment monitoring
  • eco-hydrology
  • Heihe River Basin
access type Otwarty dostęp

Utility Based Data Gathering in Mobile Sensor Network

Data publikacji: 05 Jun 2013
Zakres stron: 953 - 972

Abstrakt

Abstract

Traditional data gathering approaches cannot be applied to Mobile Sensor Network (MSN) due to sparse network density and sensor node mobility. In this paper, we propose a utility based data gathering protocol (UDG). The distance utility is used to indicate the closeness between sensor nodes and the sink node, and the activity utility is used to evaluate the ability of sensor nodes acting as relays. UDG combines the distance utility with the activity utility to make routing decisions. It also presents a buffer management scheme based on the utility. Experimental results show that UDG achieves desirable performance with low delivery overhead.

Index terms

  • Mobile sensor network
  • location prediction
  • order- Markov chain
  • distance
  • activity
  • utility
  • data gathering
access type Otwarty dostęp

A Blind Source Separation Method for Convolved Mixtures by Non-Stationary Vibration Signals

Data publikacji: 05 Jun 2013
Zakres stron: 973 - 992

Abstrakt

Abstract

A simple and feasible of BSS method to separate the convolution mixture of non-stationary vibration signals is present in this paper. The method is carried out by means of two iterative procedures: The first procedure is to estimate the coefficients of the filters. The independence criterion is used and the unknown filters are obtained by a back propagation procedure by means of simplifying the coefficients of filters. The next procedure is to estimate the source vibration signals. The coupled vibration signals are obtained by means of the filters gotten from the former procedure and the estimation sources are obtained through decoupled procedure. Simulation and experiment results show that the method is effective. This improved method can be used to separate convolutive mixtures with non-stationary mechanical vibrations.

Index terms

  • Mechanical Vibration
  • Blind Source Separation
  • Convolutive Mixture
  • Non-stationary
access type Otwarty dostęp

BI-Filtered Forwarding: A Quasi-Optimal Routing Algorithm for Query Delivery in Wireless Sensor Networks

Data publikacji: 05 Jun 2013
Zakres stron: 993 - 1011

Abstrakt

Abstract

A quasi-optimal query propagation algorithm Bi-Filtered Forwarding (BFF) for quickly routing a query throughout a wireless sensor network is proposed in this paper. BFF is implemented in a limited flooding manner for guaranteeing quick query propagation and low message consumption in wireless sensor networks. The experimental results show that in comparison with the flooding algorithm, BFF can greatly reduce the redundant message consumption during the procedure of real time query propagation throughout a wireless sensor network.

Index terms

  • Real time routing
  • distributed query processing
  • query propagation
  • constrained flooding
  • wireless sensor networks
access type Otwarty dostęp

Design And Realization of a UHF RFID Interrogator

Data publikacji: 05 Jun 2013
Zakres stron: 1012 - 1031

Abstrakt

Abstract

RFID is a generic item which uses radio waves to automatically identify objects and people. This paper presents a flexible RFID interrogator system architecture which could support various kinds of RFID standards and realizes a UHF RFID interrogator based on the EPC global C1G2 standard in details. The proposed interrogator system consists of RF analog front end, digital baseband and MAC layer. The system circuit contains a FPGA chip and peripheral circuits. NiosII core as a controller is inserted in FPGA. The proposed FPGA based baseband platform could implement various kinds of RFID standards, and efficiently reduce the design time and development cost.

Index terms

  • RFID
  • interrogator
  • reader
  • UHF
  • EPC C1G2
  • baseband
  • transceiver
access type Otwarty dostęp

An Estimation Algorithm for Missing Data in Wireless Sensor Networks

Data publikacji: 05 Jun 2013
Zakres stron: 1032 - 1053

Abstrakt

Abstract

For estimating the missing data of wireless sensor networks, an estimation algorithm called HD method, which can make use of sensoring space-time correlation of the data, was proposed based on mathematical Hermite and DESM statistical models. The algorithm not only can adaptively adjust the time and space weights, but also can accurately estimate the missing or unavailable data. The experimental results show that the algorithm has good stability and relatively high estimation accuracy.

Index terms

  • Wireless sensor network
  • missing data
  • mathematical model
  • estimation algorithm
  • spacetime correlation
access type Otwarty dostęp

Duty Cycling in Target Monitoring Wireless Sensor Network Systems

Data publikacji: 05 Jun 2013
Zakres stron: 1054 - 1076

Abstrakt

Abstract

Duty cycling is an important method for energy constrained sensor network systems to prolong lifetime. Current research on duty cycling is mainly based on such assumption that all the sensory coverage should be maintained while some nodes are sleeping. However, for the applications of target monitoring, it is not necessary anymore to keep the whole sensory coverage of the sensor network. It only needs to make sure that such kinds of nodes are active which can perceive the activities of the monitored targets. This paper proposes a novel duty cycling design for target monitoring sensor networks, which includes two algorithms - sleep scheduling algorithm and gradient query algorithm based on sleep periods. In the proposed design, most of sensor nodes are sleeping, while still keep the functions of target monitoring and information query in the sensor networks. The performance of our design has been evaluated through both theoretical analysis and simulations, which prove the functionality of the proposed design on the reduction of energy consumption.

Index terms

  • Duty cycling
  • sleep scheduling
  • gradient query
  • target monitoring
  • wireless sensor network systems
access type Otwarty dostęp

Comparative Study of Pressure Wave Mathematical Models for Hp Fuel Pipeline of Ceup at Various Operating Conditions

Data publikacji: 05 Jun 2013
Zakres stron: 1077 - 1101

Abstrakt

Abstract

High pressure (HP) Fuel Pipeline is one of the major components of Combination Electronic Unit Pump (CEUP) fuel injection system which has important role in building up of fuel pressure necessary for fuel injection. Three different 1D mathematical models of damped wave equation (WE) namely linear damped, viscous damped and damped model have been developed in MATLAB to investigate fuel pressure inside HP fuel pipeline of CEUP fuel injection system at various operating conditions of diesel engine. Lab experiments have been conducted to measure the pump side and injector side pressures by using KISTLER 4067 piezoresistive pressure sensors under controlled environment. Each model has been verified by comparing its simulated results with those of experimentally verified AMESim numerical model of CEUP system. Model evaluation statistical techniques like “Root Mean Square Error” (RMSE) and “Index of Agreement” (IA) have been used to quantify the predicted results of each mathematical model at various operating conditions. From analytical and quantitative analysis it has been concluded that viscous damped mathematical model predicts more accurately as compared to rest of models specially at all combinations of cam rotational speeds and cam angles of 700rpm, 1100rpm and 6°CaA, 10°CaA and 14°CaA respectively. Damped mathematical model predictions have been found relatively more precise at cam angles of 6°CaA and cam rotational speeds of 900rpm and 1300rpm. Moreover linear model was accurate at cam rotational speed of 900rpm and cam angle of 14°CaA.

Index terms

  • Wave equation
  • Mathematical model
  • High pressure fuel pipeline
  • Finite difference
  • RMSE
  • IA
access type Otwarty dostęp

The Effects of MOS Layers on Sensing Properties of MOS Photosensor

Data publikacji: 05 Jun 2013
Zakres stron: 1102 - 1110

Abstrakt

Abstract

In this research work, many samples of metal –oxide –silicon photosensors were laboratory prepared by thermal evaporation techniques. Some silicon samples were left in the air for a predefined time for SiO2 to grow naturally, while others were thermally coated with measured thickness of SiO. A number of the samples were coated with nickel while others with aluminum and one sample was coated with indium. Various tests and measurements were conducted; these include transmittance tests with a range of wavelength and for different thicknesses. The ideality factors of the samples and the potential barrier height were calculated from I-V and C-V characteristics. The photogenerated current of the samples were also measured at photoconductive mode under reverse voltage. Quantum efficiency measurement indicated that native oxide samples provided higher quantum efficiency than those thermally deposited samples. Detectivity measurement showed that thermally deposited oxide samples had low detectivity as compared to native oxide samples

Index terms

  • Schottky Barrier Diode
  • Photosensor
  • MOS Photosensor
  • Silicon Photosensor:
access type Otwarty dostęp

A reliable signal conditioning circuit to acquire human biopotentials

Data publikacji: 05 Jun 2013
Zakres stron: 1116 - 1132

Abstrakt

Abstract

It is well known that every human being is a complex system made up of cells, tissues, organs and organ systems that function together to maintain its health. The coordinated physiological processes maintain most of the steady states in an organism, not at a fixed value, but within a narrow, relatively constant range, known as homeostasis [1]. Recently, a non-invasive measurement of human biopotentials has been proposed in order to provide information about the condition of the human system as a whole [2]. In this work, the development of two identical signal conditioning circuits that facilitate the acquisition of the human biopotentials simultaneously from both the hands has been presented. The objective of developing these circuits is to enhance the signal levels of both the measured biopotentials uniformly and faithfully, without distortion. This is expected to enable a more reliable and detailed analysis of the acquired signals in future.

Słowa kluczowe

  • human system
  • bioelectric signals
  • signal conditioning circuit
  • static and dynamic calibration
  • statistical analysis
access type Otwarty dostęp

PLC Based Adaptive Fuzzy PID Speed Control of DC Belt Conveyor System

Data publikacji: 05 Jun 2013
Zakres stron: 1133 - 1152

Abstrakt

Abstract

Conveyor belt system is one of the most common transfer systems used in industry to transfer goods from one point to another in a limited distance. It is used in industries such as the electro- mechanical/mechanical assembly manufacturing to transfer work piece from one station to another or one process to another in food industries. The belt conveyor system discussed in this paper is driven by a DC motor and two speed controllers. The PID speed controller is designed to provide comparison to the main controller which is the Adaptive Fuzzy PID Speed controller. Both controllers are implemented in a real hardware where the algorithm will be written in PLC using SCL language. The experimental result shows that Adaptive Fuzzy PID controller performs better and adapted to the changes in load much faster than the conventional PID controller. This project has also proved that PLC is capable of performing high level control system tasks.

Index terms

  • DC belt conveyor system
  • speed controller
  • adaptive fuzzy PID
  • programmable logic controller
  • structured control language
access type Otwarty dostęp

Dielectric Resonator Antenna as a RFID Tag for Human Identification System in Wrist Watch

Data publikacji: 05 Jun 2013
Zakres stron: 1153 - 1166

Abstrakt

Abstract

Radio Frequency Identification (RFID) has been considered as a time and money-saving solution for a wide variety of applications, such as manufacturing, supply chain management, and inventory control. However, there is a growing need in the RFID community to research and find out the tag with miniature, circular polarized radiation patterns, dual band operation, high radiation efficiency and high bandwidth operations. This paper presents compact radio frequency identification (RFID) tag for human identification system in wrist watch. Dielectric resonator antenna (DRA) with patch is used as an active tag. The proposed antenna is operated on dual frequency bands. Simple microstrip line is used as a feeding mechanism. It is operated at 2.4 GHz and 5.8 GHz frequency band. It has circular polarization radiation patterns. Simulation results are presented on various parametric studies on the RFID tag.

Słowa kluczowe

  • Dielectric Resonator Antenna
  • RFID tag
  • human identification system
access type Otwarty dostęp

A Simplified Model Structure for an Activated Sludge System

Data publikacji: 05 Jun 2013
Zakres stron: 1167 - 1179

Abstrakt

Abstract

Activated sludge system is the essential technology in use for municipal wastewater treatment plant. The system design for pollutants removal, safety analysis and experimentation relied upon an effective, straightforward and reliable model. However, most of the available models are too complex to use for control purposes either practically or via simulation. Therefore, vehement need for a simplistic and efficient model could not be avoided. This paper presents a simplified model structure for an activated sludge system using neuro-fuzzy system. Efficiency, ease of use, effectiveness and fast convergence are some of the alluring qualities of neuro-fuzzy technique. Building a reliable and flexible model requires validation with full scale or experimental data. Therefore, with the use of the full-scale data from the domestic wastewater treatment plant in Malaysia, the validation was achieved. For comparison, auto regressive with exogenous input (ARX) model was used. Simulation studies showed that the proposed method produced promising results, thus revealing the technique is effective and robust in modelling the activated sludge system.

Index terms

  • Model
  • pollutants
  • neuro-fuzzy
  • anfis
  • parameters
access type Otwarty dostęp

Model Based Application Level Middleware for Design of Wireless Smart City

Data publikacji: 05 Jun 2013
Zakres stron: 1180 - 1199

Abstrakt

Abstract

The Wireless Smart City (WSC), an emerging concept in Smart Grid and Internet of Things, has attracted an increasing number of customers and developers - based with its promise of low cost implementation and flexibility. At the same time, the challenges faced with in the field applications hinder the progress of WSC from researches into commercial production. A model based application level auxiliary platform is presented to help the development of WSC. This middleware together with the existing network simulators replace field test during WSC design. The proposed platform reduces engineering cost and increases development efficiency. Network optimization is implemented to provide an automatic design of WSC.

Index terms

  • Smart City
  • Performance Evaluation
  • Optimal Deployment
  • Simulated Annealing
  • Wireless Sensor Network
access type Otwarty dostęp

Multiple Parameter Monitoring System for Landslide

Data publikacji: 05 Jun 2013
Zakres stron: 1200 - 1229

Abstrakt

Abstract

China has complex terrain where landslide happens very frequently, thus leading to serious damages sometimes. So in China much attention is paid to the monitoring of landslide. There are various methods in landslide monitoring all over the world. Bas1200ed on the analysis on previous landslide monitoring instruments, this paper designs a new kind landslide monitoring system, which can monitor three parameters of different depth at a time: internal displacement, internal geotechnical pressure and pore water pressure. The system consists of three parts: mechanical structure, monitoring system and PC software. In this system the data collected by sensors are firstly stored in the SD card, and the user will be able to read the monitoring data at regular intervals instead of monitoring data changing timely, which can save labor, especially at the initial stage of landslide. At last laboratory testing has been done to verify the accuracy of this measuring system and the result satisfies the design requirements.

Index terms

  • Landslide
  • monitoring
  • internal geotechnical pressure
  • pore water pressure
  • internal displacement
access type Otwarty dostęp

Fall Detection and Prevention for the Elderly: A Review of Trends and Challenges

Data publikacji: 05 Jun 2013
Zakres stron: 1230 - 1266

Abstrakt

Abstract

It is of little surprise that falling is often accepted as a natural part of the aging process. In fact, it is the impact rather than the occurrence of falls in the elderly, which is of most concern. Aging people are typically frailer, more unsteady, and have slower reactions, thus are more likely to fall and be injured than younger individuals. Typically, research and industry presented various practical solutions for assisting the elderly and their caregivers against falls via detecting falls and triggering notification alarms calling for help as soon as falls occur in order to diminish fall consequences. Furthermore, fall likelihood prediction systems have been emerged lately based on the manipulation of the medical and behavioral history of elderly patients in order to predict the possibility of falls occurrence. Accordingly, response from caregivers may be triggered prior to most fall occurrences and accordingly prevent falls from taking place. This paper presents an extensive review for the state-of-the- art trends and technologies of fall detection and prevention systems assisting the elderly people and their caregivers. Furthermore, this paper discusses the main challenges, facing elderly fall prevention, along with suggestions for future research directions.

Index terms

  • Fall detection
  • fall prevention
  • elderly monitoring
  • motion sensing
access type Otwarty dostęp

Field Programmable Gate Array Based Embedded System for Non-Invasive Estimation of Hemoglobin in Blood using Photoplethysmography

Data publikacji: 05 Jun 2013
Zakres stron: 1267 - 1282

Abstrakt

Abstract

In this paper, a Field Programmable Gate Array (FPGA) based embedded system has been proposed for non-invasive detection of hemoglobin in blood using photoplethysmography. Photoplethysmography (PPG) is a non-invasive and low-cost optical technique that can be used to detect blood volume changes in the micro-vascular bed of tissue. Our investigations revealed that volume of water present in blood considerably affects the reading of the concentration of blood hemoglobin. In our current work, the proposed device is developed with monitoring of PPG waves at three wavelengths so as to compensate for the error due to absorption of near infrared radiation (NIR) by water in the blood. The device also has been developed to be robust enough to tolerate distortions in the waveform due to motion of the subject. In order to sense the motion of the subject a 3-axis accelerometer has been used and correction is suitably applied to the sensed waveform. As a result, it is possible to measure the concentration of hemoglobin in blood while the subject is on the move.

Index terms

  • Field Programmable Gate Array
  • photoplethysmography
  • non invasive estimation
  • near infra red radiation
access type Otwarty dostęp

Development of a Cardan Mechanism for the Asteroid Lander

Data publikacji: 05 Jun 2013
Zakres stron: 1283 - 1297

Abstrakt

Abstract

It is of great significance for improving the landing stability and adjusting the attitude of equipment base by designing a cardan mechanism in the asteroid lander. In the paper, a cardan mechanism having cushion and attitude adjusting functions is designed for the asteroid lander. The cardan mechanism contains electromagnetic damping, belt transmission and cross-shaft, and it has merits of adjustable damping and bearing large overload. The attitude control system of the cardan mechanism is built by FPGA chip. Kinematics and kinetics of the cardan mechanism are analyzed for attitude control. Complex feedback PD controller is applied to control the attitude of the cardan mechanism as large mass equipment base would influence control performance. This controller contains real time gravity compensation, desired acceleration compensation and velocity feed forward compensation. The experiments show that the cardan mechanism designed in this paper has good performance by adopting Complex feedback PD controller.

Index terms

  • Cardan mechanism
  • kinematics
  • kinetics
  • complex feedback PD controller
  • asteroid lander

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