Design, development and control of a new generation high performance linear actuator for parallel robots and other applications

The main focus of this research is to design and develop a high performance linear actuator based on a four bar mechanism. The present work includes the detailed analysis (kinematics and dynamics), design, implementation and experimental validation of the newly designed actuator. High performance is characterized by the acceleration of the actuator end effector. The principle of the newly designed actuator is to network the four bar rhombus configuration (where some bars are extended to form an X shape) to attain high acceleration. Firstly, a detailed kinematic analysis of the actuator is presented and kinematic performance is evaluated through MATLAB simulations. A dynamic equation of the actuator is achieved by using the Lagrangian dynamic formulation. A SIMULINK control model of the actuator is developed using the dynamic equation. In addition, Bond Graph methodology is presented for the dynamic simulation. The Bond Graph model comprises individual component modeling of the actuator along with control. Required torque was simulated using the Bond Graph model. Results indicate that, high acceleration (around 20g) can be achieved with modest (3 N-m or less) torque input. A practical prototype of the actuator is designed using SOLIDWORKS and then produced to verify the proof of concept. The design goal was to achieve the peak acceleration of more than 10g at the middle point of the travel length, when the end effector travels the stroke length (around 1 m). The actuator is primarily designed to operate in standalone condition and later to use it in the 3RPR parallel robot. A DC motor is used to operate the actuator. A quadrature encoder is attached with the DC motor to control the end effector. The associated control scheme of the actuator is analyzed and integrated with the physical prototype. From standalone experimentation of the actuator, around 17g acceleration was achieved by the end effector (stroke length was 0.2m to 0.78m). Results indicate that the developed dynamic model results are in good agreement. Finally, a Design of Experiment (DOE) based statistical approach is also introduced to identify the parametric combination that yields the greatest performance. Data are collected by using the Bond Graph model. This approach is helpful in designing the actuator without much complexity

Cross-Layer Optimization of Fast Video Delivery in Cache-Enabled Relaying Networks

This paper investigates the cross-layer optimization of fast video delivery and caching for minimization of the overall video delivery time in a two-hop relaying network. The half-duplex relay nodes are equipped with both a cache and a buffer which facilitate joint scheduling of fetching and delivery to exploit the channel diversity for improving the overall delivery performance. The fast delivery control is formulated as a two-stage functional non-convex optimization problem. By exploiting the underlying convex and quasi-convex structures, the problem can be solved exactly and efficiently by the developed algorithm. Simulation results show that significant caching and buffering gains can be achieved with the proposed framework, which translates into a reduction of the overall video delivery time. Besides, a trade-off between caching and buffering gains is unveiled.Comment: 7 pages, 4 figures; accepted for presentation at IEEE Globecom, San Diego, CA, Dec. 201

Non-Orthogonal Multiplexing of Ultra-Reliable and Broadband Services in Fog-Radio Architectures

The fifth generation (5G) of cellular systems is introducing Ultra-Reliable Low-Latency Communications (URLLC) services alongside more conventional enhanced Mobile BroadBand (eMBB) traffic. Furthermore, the 5G cellular architecture is evolving from a base station-centric deployment to a fog-like set-up that accommodates a flexible functional split between cloud and edge. In this paper, a novel solution is proposed that enables the non-orthogonal coexistence of URLLC and eMBB services by processing URLLC traffic at the Edge Nodes (ENs), while eMBB communications are handled centrally at a cloud processor as in a Cloud-Radio Access Network (C-RAN) system. This solution guarantees the low-latency requirements of the URLLC service by means of edge processing, e.g., for vehicle-to-cellular use cases, as well as the high spectral efficiency for eMBB traffic via centralized baseband processing. Both uplink and downlink are analyzed by accounting for the heterogeneous performance requirements of eMBB and URLLC traffic and by considering practical aspects such as fading, lack of channel state information for URLLC transmitters, rate adaptation for eMBB transmitters, finite fronthaul capacity, and different coexistence strategies, such as puncturing.Comment: Submitted as Journal Pape

Analysis and design of BICM-OFDM and buffer-aided relaying

The growing demand for high data rates, reliability, network densification, and coverage extension will make relaying one of the key enabling technologies in future wireless cellular and broadband access networks. As the underlying channels in broadband wireless communication experience frequency-selective fading, it is necessary to study new relaying schemes to exploit the inherent diversity offered by the frequency-selective channels. We adopt the combination of bit-interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM) to combat frequency-selective fading. We propose and analyze several new half-duplex (HD) BICM-OFDM relaying schemes for single- and multi-source communication systems. We derive the asymptotic pairwise error probability (PEP) and show that the proposed schemes can successfully extract full space and frequency diversity offered by the channel. The PEP expressions are exploited to develop guidelines for system design such as sub-carrier allocation, relay selection, relay grouping, relay placement, and power allocation. Although conventional HD relaying schemes, where relays receive and transmit according to a pre-fixed schedule, are simple in operation, their performance can be limited because the best links may not be exploited, in particular, when the channel changes from one time slot to the next. To circumvent this problem, we present buffer-aided relaying protocols where the relay decides on its transmission and reception based on the instantaneous qualities of the source-relay and relay-destination channels. For both flat-fading and frequency-selective fading links, we propose link selection protocols for buffer-aided relaying, which can yield a large coding and/or diversity gain advantage over conventional HD relaying for finite and infinite buffer sizes. We assume that the channel state information (CSI) can be outdated when link selection is performed and show that if both the instantaneous signal-to-noise ratio (SNR) and the reliability of the CSI estimates are incorporated into the link selection protocols, a lower error rate can be achieved compared to considering the SNR only. We introduce a decision threshold to the link selection protocols, which can be tuned to ensure buffer stability and trade error rate with delay and/or throughput.Applied Science, Faculty ofElectrical and Computer Engineering, Department ofGraduat

A Proposed Framework for Fingerprint-based Voting System in Bangladesh

The objective of this project is to improve the existing voting system that will be accurate, transparent, and faster and will ensure a single vote for a single person. Our proposed system has covered all of these issues successfully. This product is affordable by many organizations where preferential elections conducted. The product is a prototype and can be implemented for vast use. Voting is an onerous task for the election commission to conduct free and fair polls in our country, the largest democracy in the world. A lot of money has been spent on this to make sure that the elections are rampage free. But, now- a -days it has become very usual for some forces to indulge in rigging which may eventually lead to a result contrary to the actual verdict given by the people. In order to provide inexpensive solutions to the above, this project is implemented with the biometric system i.e. fingerprint scanning. This is used to ensure the security to avoid fake, repeated voting, etc. It also enhances the accuracy and speed of the process. The system uses a thumb impression for voter identification as we know that the thumb impression of every human being has a unique pattern. Thus it would have an edge over the present-day voting systems. The purpose of such a system is to ensure that the voting rights are accessed only by a legitimate user and no one else. In this, creation of a database consisting of the thumb impressions of all the eligible voters in a constituency is done as a pre-poll procedure. During elections, the thumb impression of a voter is entered as input to the system. This is then compared with the available records in the database. If the particular pattern matches with anyone in the available record, access to cast a vote is granted. But in case the pattern doesn’t match with the records of the database or in case of repetition, access to cast a vote is denied or the vote gets rejected. The result is instantaneous and counting is done. The overall cost for conducting elections gets reduced and so does the maintenance cost of the systems

Analysis and Design of Cooperative BICM-OFDM Systems

In this paper, we propose a novel cooperative diversity scheme for wireless systems employing the combination of bit–interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). The proposed scheme utilizes an amplify–and–forward protocol where relays are assigned to multiple groups. Relays in the same group transmit concurrently over disjoint sets of sub–carriers and relays in different groups transmit in different time slots. We derive closed–form expressions for the asymptotic worst–case pairwise error probability and the diversity gain of the proposed cooperative BICM–OFDM scheme. Based on the derived analytical results we develop design guidelines for sub–carrier allocation, relay grouping, and relay selection. Simulation results corroborate the derived analytical results and confirm the effectiveness of the developed optimization framework

The contamination appraisal and depthwise scrutiny of trace elements in sediments of the Moyur river, Bangladesh

Trace element pollution in river sediments from multiple sources can pose ecological risks to aquatic systems. Therefore, the evaluation of elemental contamination and ecological risks in sediments is important for the proper management of a river system. In this study, concentrations of 12 major and trace elements (Cr, Mn, Fe, Al, Br, Rb, V, Co, As, Ta, Th, and U) were measured in sediments of the Moyur River, Bangladesh using neutron activation analysis technique. It is observed that concentrations of As, Br, Rb, Ta, Th, and U are higher than those of the upper continental crustal average values. Different environmental contamination indicators suggest that Moyur River sediments are heavily contaminated by Br. The pollution load index derived from the contamination factor also indicate the deteriorating condition of the sediments at different sampling points of the river. The depth-wise variation of the trace elements elucidates their contamination profiles along the sediment cores. An ecological risk assessment by different ecological risk factors and sediment quality guidelines indicates that sediments of the Moyur River are subjected to ecological risk by Cr and As. The multivariate statistical analyses indicate the origin and transport behavior of the studied elements in the sediments of the river. This study will provide baseline elemental concentration data for future monitoring of the contamination and to develop effective pollution control strategies for this urban river

Network coded multi-source cooperative communication in BICM-OFDM Networks

In this paper, we study a cooperative diversity scheme for wireless systems employing network coding and the combination of bit-interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). The considered system comprises multiple sources, one relay, and one destination. The relay decodes the signal received from all sources and performs network coding before forwarding the signal to the destination. We propose a simple cooperative maximum-ratio combining scheme for the destination which can successfully exploit the full spatial and frequency diversity offered by the channel for arbitrary numbers of sources and arbitrary linear modulation schemes. Furthermore, we propose techniques to reduce the signaling overhead and the decoding complexity at the destination. To gain insight for system design, we derive a closed-form upper bound for the asymptotic worst-case pairwise error probability and the diversity gain of the considered network coded cooperative BICM-OFDM system. These analytical results reveal the influence of various system parameters, including the number of sources, the free distance of the code, and the frequency diversity of the involved links, on performance. Based on the derived analytical results, we develop schemes for optimal relay placement and power allocation. Simulation results corroborate the derived analytical results and confirm the effectiveness of the developed optimization framework