Search results for "DT"
showing 10 items of 2454 documents
New Solution for Telescopic Robotic Arm
2014
This paper deals with a Robotic arm actuated by a monomobil telescopic planetary gear and servo DC motor. Experimental model of robot was designed and manufactured at the Faculty of Engineering from Sibiu, (Patent no. 112418 CI6.B25J 18/02). The Servo DC as actuator drives a reel. Wires on the reel will produce displacement of telescopic modules from robotic arm structure. The reference as a voltage for future arm displacement is provided by a PWM generator. The rotation of the reel in one way or another has the effect of lengthening or shortening robotic arm. Robotic arm length is directly related to the PWM signal. Control of robotic arm positioning is done with a linear transducer.
Aggregated Packet Transmission in Duty-Cycled WSNs: Modeling and Performance Evaluation
2017
[EN] Duty cycling (DC) is a popular technique for energy conservation in wireless sensor networks (WSNs) that allows nodes to wake up and sleep periodically. Typically, a single-packet transmission (SPT) occurs per cycle, leading to possibly long delay. With aggregated packet transmission (APT), nodes transmit a batch of packets in a single cycle. The potential benefits brought by an APT scheme include shorter delay, higher throughput, and higher energy efficiency. In the literature, different analytical models have been proposed to evaluate the performance of SPT schemes. However, no analytical models for the APT mode on synchronous DC medium access control (MAC) mechanisms exist. In this …
Efficient CAD of Optimal Multi-Port Junctions Loaded with Partial-Height Cylindrical Posts using the 3D BI-RME Method
2005
A rigorous full-wave technique based on the 3D BI-RME (Boundary Integral-Resonant Mode Expansion) method for the analysis and design of compensated waveguide junctions is presented. This method is used to investigate the electrical performance of right-angled bends and rectangular waveguide T-junctions loaded with partial-height cylindrical posts, with the aim of extending the typical usable bandwidths of such components. It is found that the electrical performance of a two-way power divider can be significantly improved by considering a post displaced along the symmetry plane of the structure. Therefore, this contribution reveals a new crucial design parameter not considered in previous wo…
A low-cost compact uniplanar Quasi–Yagi printed antenna
2008
A low cost directive uniplanar broadband printed Quasi–Yagi antenna design is presented. As a particular realization, some prototypes have been designed to operate in the 2.45 GHz band. They have been then modeled, fabricated onto standard printed circuit dielectric substrate and tested successfully. For the design and the modeling processes, we have make use of FDTD based in-house developed algorithms. The obtained bandwidth is, for all the considered cases, better than 15%. The main radiation characteristics are 2–5.5 dBi gain, depending on the number of director elements, and better than 25 dB front-to-back ratio. Overall antenna size was, in any case lesser than 1 λ × 0.5 λ. © 2008 Wile…
Two Methods to Broaden the Bandwidth of a Nonlinear Piezoelectric Bimorph Power Harvester
2017
We propose two methods to broaden the operation bandwidth of a nonlinear pinned–pinned piezoelectric bimorph power harvester. The energy-scavenging structure consists of a properly poled and electroded flexible bimorph with a metallic layer in the middle, and is subjected to flexural vibration. Nonlinear effects at large deformations near resonance are considered by taking the in-plane extension of the bimorph into account. The resulting output powers are multivalued and exhibit jump phenomena. Two methods to broaden the operation bandwidth are proposed: The first method is to extend the operation frequency to the left single-valued region through optimal design. The second method is to exc…
Finite-Difference Time-Domain Simulation of Towers Cascade Under Lightning Surge Conditions
2015
In this paper, the simulation of towers cascade under lightning surge conditions is presented. Finite-difference time-domain method is used to solve both the Maxwell's and telegraph equations. Maxwell's equations and the time-domain resistivity model of Darveniza are used to simulate the nonlinear behavior of the grounding system. Telegraph equations are used to describe the propagation in the overhead lines. Multiple ionizations, on different grounding electrodes belonging to various towers, can be implemented simultaneously, without making assumptions on the shape of the ionized areas.
PAUT inspection of complex-shaped composite materials through six DOFs robotic manipulators
2015
The requirement to increase inspection speeds for the non-destructive testing (NDT) of composite aerospace parts is common to many manufacturers. The prevalence of complex curved surfaces in the industry provides significant motivation for the use of six-axis robots for the deployment of NDT probes in these inspections. The IntACom project, developed by TWI Technology Centre (Wales) and supported by a number of major aerospace partners and the Welsh government, has produced a prototype robotic NDT system. The prototype system is capable of inspecting complex-geometry composite components with great time savings. Two six-axis robotic arms deploy end effectors carrying phased array ultrasonic…
Reconstruction and simulation of the vehicle to road safety barrier oblique collision based on the Levenberg–Marquardt algorithm
2012
Vehicle crash modeling and reconstruction is an important field for research since the safety statistics from many countries show that the fatality rate of passenger vehicle occupants involved in road accidents is high. In particular, side impact are considered to be a serious problem. For this reason, in this paper, there is presented a methodology to reconstruct a given vehicle to road safety barrier oblique collision. An easy to analyze, viscoelastic model is established to represent a vehicle crash event. The reasonable modeling simplifications are assumed (namely: the vehicle is rigid and deformation of the safety barrier is negligible) which let the computational efficiency of the pro…
Implementation and experimental validation of a real-time PWM algorithm based on B-Spline carriers for three phase voltage source inverters
2009
This paper presents the implementation and experimental results of an algebraic real-time sinusoidal pulse width modulation algorithm (SPWM) based on B-Spline carriers. B-spline functions are used as carrier signals with the aim to to reduce harmonic content of the three phase inverter output voltage. The presented algorithm eliminates the problem of B-spline recursive evaluation with convolution integrals or convolution sums in digital counterpart. The pulse pattern synthesis is made with the help pre-calculated duty cycle expressions. In this way there is no real need to synthesize the carrier signal so the hardware and the whole inverter control system becomes cheaper, more reliable and …
A DRO-based X-band injection-locked amplifier without input non-reciprocal elements
2009
Conventional design of injection-locked amplifiers (ILA's) implies the use of a non-reciprocal (ferrite, usually) element for separating the input signal from the synchronized output signal. In this paper a novel topological structure is proposed which permitted the realization of a wide-band, transmission-type, ILA with no need for separating input-port isolator or preamplifier. The prototype, realized in HMIC technology, while intended only as demonstrator of the newly proposed approach in the design of ILA's, shows quite satisfactory performances at X-band, with a simple, compact and low-cost structure.