Performance Evaluation Of Transmission Research Articles

Performance evaluation and dimensional optimization design of planar 6R redundant actuation parallel mechanism

AbstractAiming at the problems of small good workspace, many singular configurations, and limited carrying capacity of non-redundant parallel mechanisms, a full-redundant drive parallel mechanism is designed and developed, and its performance evaluation, good workspace identification, and scale optimization design are studied. First, the kinematics analysis of the planar 6R parallel mechanism is completed. Then, the motion/force transmission performance evaluation index of the mechanism is established, and the singularity analysis of the mechanism is completed. Based on this, the fully redundant driving mode of the mechanism is determined, and the good transmission workspace of the mechanism in this mode is identified. Then, the mapping relationship between the performance and scale of the mechanism is established by using the space model theory, and the scale optimization of the mechanism is completed. Finally, the robot prototype is made according to the optimal scale, and the performance verification is carried out based on the research of dynamics and control strategy. The results show that the fully redundant actuation parallel mechanism obtained by design optimization has high precision and large bearing capacity. The position repeatability and position accuracy are 0.053 mm and 0.635 mm, respectively, and the load weight ratio can reach 15.83%. The research results of this paper complement and improve the performance evaluation and scale optimization system of redundantly actuated parallel mechanisms.

Evaluation of THz wave transmission performance in TOPAS-based heptagonal photonic crystal fiber (He-PCF)

PCF denotes photonic crystal fiber which is utilized for terahertz (THz) waveguides and cladding in the shape of a hexagon with two elliptical air apertures (AHs), which are discussed. Such differentiation is made: When the frequency is 1 THz, effective material loss (EML) to a minimum of 0.028 cm−1 has been achieved. Making use of the heptagonal photonic crystal fiber (He-PCF) architecture, every simulation result utilizing COMSOL Multiphysics software implements the perfectly match layer (PML) and finite element method (FEM) boundary conditions. The He-PCF fiber demonstrates an effective mode loss (EML) of 0.028 cm−1 that is negligible, a substantial effective area (EA) measuring 7.31 × 10−8 m2 and an 80 % power concentration encompassing the central area at 1 THz frequency. Furthermore, regarding crucial optical guiding aspects like confinement loss, dispersion, and modality, a small study with respect to power fraction along with effective mode area (EMA) has again been conducted. Here, He-PCF THz waveguide is anticipated to provide a notable improvement in the current design for the communication field. Moreover, our suggested the PCF demonstrates perception by a solitary mode, as indicated through the utilization of the V-parameter, across a range in frequency spanning among 0.80 and 3 THz. Thus, it is anticipated that the layout of He-PCF fibers will facilitate efficient transmission of terahertz (THz) signals in a variety of communication applications.

Performance Evaluation of Optical Transmission Based on Link Estimation by Using Deep Learning Techniques

Performance Evaluation of Optical Transmission Based on Link Estimation by Using Deep Learning Techniques

Transmission Performance Evaluation of Local 5G Downlink Data Channel in SU-MIMO System under Outdoor Environments

Transmission Performance Evaluation of Local 5G Downlink Data Channel in SU-MIMO System under Outdoor Environments

Extension of transmission performance evaluation for planar higher pair mechanisms

Comprehensive and accurate evaluation of performance is essential for profile synthesis and profile analysis of higher pair mechanisms. Aiming at the transmission performance of planar higher pair mechanisms, the evaluation indices and methods are proposed from different perspectives. On the one hand, the kinematic performance indices in lower pair mechanisms are extended to higher pair mechanisms, including the mechanical advantage and the generalized pressure angle. On the other hand, novel indices specific to higher pair mechanisms are developed, including the contact closure index and the singularity distance index. Considering the performance of individual elements and that of the overall joint, the transmission performance of higher pairs is subdivided into element-based performance and joint-based performance, and the evaluation indices are classified accordingly. A graphical mapping method based on element-based performance is further proposed for intuitive analysis and qualitative evaluation. Practical examples validate the effectiveness of the proposed indices and methods for evaluating the performance of higher pair mechanisms, as well as their potential to enable optimal profile solution selection and design in the profile synthesis process.

Transmission performance evaluation of non-circular spur bevel gear based on a novel isochronal measurement method

This paper aims to study the transmission performance evaluation of non-circular spur bevel gear (NCSB-gear) based on a novel isochronal measurement method. Firstly, the mathematical model of NCSB-gear is established. Then a novel isochronal measurement method is proposed, and the actual tooth surfaces are reconstructed by non-uniform rational B-spline interpolation. The advantages of the proposed method are discussed based on the geometric characteristics of tooth surface and measurement fitting error. A pair of forged NCSB-gears is measured through a coordinate measurement machine and the maximum tooth surface fitting error by the proposed method reduces 2μm compared with the traditional method. Moreover, deviation tooth contact analysis (DTCA) and load tooth contact analysis (LTCA) are conducted to evaluate the transmission performance. Finally, the transmission performance of measured NCSB-gear is obtained by a gear rolling tester. By comparing the TCA calculation of different measurement methods, it is found that the relative error of the maximum transmission error based on the isochronal measurement method reduces 4.719% compared with the traditional measurement method, thus verifying the validity of the proposed measurement method.

Design of a New Family of Kinematically Redundant Parallel Mechanisms With Two Rotations and One Translation

Abstract This article presents a new family of kinematically redundant parallel mechanisms (KR-PMs) with two rotations and one translation (2R1T) based on the Lie group method. Compared with the 2-UPR/RPU PM, these PMs have two main advantages, namely, larger reachable workspaces of the moving platforms and higher motion/force transmission performance, as verified by three typical cases. The inverse kinematics, velocities, singularities, and workspaces of the 2-UPR/PRPU PM are analyzed in detail. A new method for motion/force transmission performance evaluation of KR-PMs in accordance with the indices for nonredundant PMs is proposed. Moreover, the local and global motion/force transmission performances of the 2-UPR/PRPU PM are determined using the new method.

Performance evaluation of an encrypted color image transmission over wireless network with different chaotic-based techniques

Performance evaluation of an encrypted color image transmission over wireless network with different chaotic-based techniques

A comprehensive evaluation framework for kinematic performance of parallel mechanisms based on joint transmissibility and multi-attribute decision making methods

The evaluation of kinematic transmission performance is one of the key elements of mechanism analysis and the foundation of optimal design, where performance indices related to motion and force transmission provide evaluation criteria for parallel mechanisms. The paper will focus on the two significant and challenging aspects of performance evaluation of parallel mechanisms: (1) presenting the generalized angle to evaluate the joint transmissibility and (2) establishing a systematic and complete multi-index comprehensive evaluation method (MICEM). Utilizing the transmission vector involving the transmissibility of all inputs and outputs, the general approaches to establishing multiple indices are further proposed to reveal performance presentations limited by a single index. Combing multiple indices and multi-attribute decision making (MADM) methods, the procedures including determining reasonable weights of the indices, screening appropriate indices, and aggregating those indices into a composite index are further developed to address the comprehensive evaluation problem. Moreover, the results of the comprehensive evaluation for a 3-RUU parallel mechanism verify the effectiveness and rationality of the new method. This work can also provide references for evaluation analysis and optimal design of different performance.

Accurate transmission performance evaluation of servo-mechanisms for robots

The Servo-Mechanisms (SMs) mounted in industrial robots joints are a major source of positioning accuracy errors . To improve robots precision performance, researchers have been focusing on the development of novel SMs design and control strategies, which need extensive experimental analyses to tune their parameters. In this context, the scope of this paper is double: first, to present the novel experimental apparatus and methods designed to improve the accuracy of the transmission performance evaluation of high dynamics SMs and, secondly, to report and discuss the achieved experimental results. In the first part, a description of the test rig tuning operations is given, primarily focusing on the signals synchronization and on the elimination of the measuring errors caused by the mechanical transmission elasticity and the servomotor torque ripples. Then, control strategies for compensating the torque ripples and input speed errors are defined. It is shown that speed oscillations can be reduced of ≈ 70 % when rotating the servomotor up to 2000 rpm, improving the measurement quality of the reducer performance. In the second part, a set of experiments is carried out to assess the combined effect of input speed and lubricant temperature on the reducer behavior. The system sensitivity to the variation of the input parameters is confirmed by the dynamic lost motion curves, whose mean value equals 16 . 8 ″ and 35 . 4 ″ when the reducer is operated at its minimum and maximum friction load respectively. At last, the extrapolated harmonic content is used to build a simple mathematical model of the reducer transmission error. • Methods employed to assess the performance of modern servo-mechanisms are reported. • Practical guidelines for improving the measurements quality are proposed. • The effect of oil temperature and input speed on the reducer is assessed. • A model of the reducer transmission error is derived from the measured data.

Implementation of Omni-D Tele-Presence Robot Using Kalman Filter and Tricon Ultrasonic Sensors

The tele-presence robot is designed to set forth an economic solution to facilitate day-to-day normal activities in almost every field. There are several solutions to design tele-presence robots, e.g., Skype and team viewer, but it is pretty inappropriate to use Skype and extra hardware. Therefore, in this article, we have presented a robust implementation of the tele-presence robot. Our proposed omnidirectional tele-presence robot consists of (i) Tricon ultrasonic sensors, (ii) Kalman filter implementation and control, and (iii) integration of our developed WebRTC-based application with the omnidirectional tele-presence robot for video transmission. We present a new algorithm to encounter the sensor noise with the least number of sensors for the estimation of Kalman filter. We have simulated the complete model of robot in Simulink and Matlab for the tough paths and critical hurdles. The robot successfully prevents the collision and reaches the destination. The mean errors for the estimation of position and velocity are 5.77% and 2.04%. To achieve efficient and reliable video transmission, the quality factors such as resolution, encoding, average delay and throughput are resolved using the WebRTC along with the integration of the communication protocols. To protect the data transmission, we have implemented the SSL protocol and installed it on the server. We tested three different cases of video resolutions (i.e., , and ) for the performance evaluation of the video transmission. For the highest resolution, our TPR takes 3.5 ms for the encoding, and the average delay is 2.70 ms with 900 × 590 pixels.

Performance Evaluation of Seamless 5G Outdoor RoFSO Transmission at 39 GHz

This letter presents results of an experimental measurement campaign involving the deployment of combined radio over the fiber and radio over free space optics (FSO) technology in the cloud-based fifth generation (5G) fronthaul network operating in the millimeter wave (mmW) area. For this purpose, we have used 10 km of optical fiber, 50 m long outdoor FSO link and 1 m long antenna seamless radio frequency transmission at 39 GHz. The results show excellent performance in terms of the phase noise and the signal-to-noise (SNR) ratio. The error vector magnitude performance depends on the modulation format and are below the standard limits for the 5G new radio signals, with 400 MHz QPSK and 64-QAM showing almost identical results for SNR of up to ~19 dB whereas 256-QAM signal offering the best spectral efficiency. Moreover, we investigate the received mmW signal deterioration due to the atmospheric conditions in the FSO channel.

Evaluation of speech transmission performance

Evaluation of speech transmission performance

Experimental performance evaluation of real-time image transmission in indoor VLC environment

Experimental performance evaluation of real-time image transmission in indoor VLC environment

Transmission Performance Evaluation of Coherent Optical Communication System based on Machine Learning

Transmission Performance Evaluation of Coherent Optical Communication System based on Machine Learning

In-service crosstalk monitoring in multicore fibers based on precoded DMT system.

In-service crosstalk monitoring based on the precoding technique in a discrete multitone (DMT) system is proposed and validated experimentally. The method relies on the ability of time-frequency domain equalization of precoded DMT. Experiments on a 20 GBaud 16 quadrature amplitude modulation DMT system over seven-core weakly coupled multicore fibers (MCFs) are conducted. The inter-core instantaneous average crosstalk (IAXT) is gathered and evaluated in a period as short as 10 µm without disturbing the signal transmission. Such IAXT has a high correlation with the bit error ratio (BER), and a transmission performance evaluation strategy of the MCF transmitting system is developed according to the relationship between IAXT and BER.

Transmission Performance Evaluation of MPR-based Wireless Communication System Applying for Disaster Investigation

Transmission Performance Evaluation of MPR-based Wireless Communication System Applying for Disaster Investigation

Performance Evaluation of Digital Transmission with Matlab on Eye Pattern Parameter

The effect of digital transmission impairments is seen from a diagram called an eye pattern. Measurements of the device can be represented in a simulation. Our motivation in conducting this simulation aims to dig deeper into the variation of parameter changes that exist in improving the eye pattern opening angle. The raised cosine pulse with roll-off (a) of 0.3 was used as the basis for this study, using the Matlab simulation. Important parameter values have been explored to show the best data. Finally, we suggest that we continue to explore optimization techniques for the best results for this eye pattern visualization.

Performance Evaluation of WDM Channel Transmission for Probabilistic Shaping With Partial Multilevel Coding

We propose partial multilevel coding (MLC) for optical communications with probabilistic shaping (PS), which improves the signal-to-noise ratio performance and makes information rates more adaptable, while reducing the power consumed by forward error correction. We designed simulation models of partial-MLC and bit-interleaved coded modulation (BICM) implementing the same low-density parity-check code to have almost the same transmission performance in an additive white Gaussian noise channel. The estimated power consumption of the partial-MLC model was about 38~39% lower than that of the BICM model. Next, we evaluated the effect of nonlinearity on fiber wavelength division multiplexing (WDM) channels in numerical simulations. The results showed that both models behaved similarly regardless of nonlinear noise, illustrating the usefulness of MLC with PS for optical transmissions on WDM channels.

Performance evaluation of DVB-t image transmission over a MIMO OWC channel at 650 nm under varying turbulence regimes

With the convergence of Information, telecom and broadband services, the digital TV broadcast has undergone a drastic change. For 5G and beyond, the Optical Wireless Communication (OWC) is gaining popularity as a distribution technology in access networks. However, OWC channel is undeterministic in nature due to its interaction with the atmosphere. A great deal of effort has been devoted in the existing literature to determine Quality of Service (QoS) performance for broadcast over an OWC channel whereas Quality of Experience (QoE) has been frequently overlooked. With this motivation, a holistic performance appraisal comprising of both QoS evaluation in terms of Symbol Error Rate (SER) and QoE assessment in terms of a visual indicator i.e. Structure Similarity Index (SSIM) is presented for a DVB-t image transmission over an OWC link under different turbulence regimes with Single Input Single Output (SISO) and Multiple Input Multiple Output (MIMO) systems. The results show that the improvements suggested by QoS from designer perspective need not necessarily pertain to quality enhancement at the end user side.