scholarly journals To Improve the Real-Time Performance of Airborne Data Link Communication System

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Gang Yao
Keyword(s):  
Real Time ◽  
Communication System ◽  
Loss Rate ◽  
Gaussian White Noise ◽  
Data Communication ◽  
Communication Process ◽  
Civil Aviation ◽  
Data Link ◽  
The Real ◽  
Time Performance

Ground-to-air data link communication has the advantages of fast transmission rate, strong anti-interference ability, and large data communication volume and has been widely used in the field of civil aviation. This article mainly studies the measures to improve the real-time performance of the airborne data link communication system. The design of the hardware platform of the jamming environment simulator needs to comprehensively consider the implementation complexity of the jamming environment model and the real-time simulation method adopted by the UAV data link system. This paper uses the multicore and multithread in the Linux operating system to simulate the functions of the original data link communication system and uses the TFT screen to display the data communication process in the multicore and multithread design scheme. When evaluating and scoring the evaluation indicators, it must be carried out in accordance with certain standards. However, most of the indicators cannot be directly assessed quantitatively only through certain specific values. This article mainly uses the AHP method to analyze the weight of indicators. In the simulation, user information is generated by a random code generator and then distributed to each branch through serial-to-parallel conversion (S/P), and the spreading process is completed by long-code spreading on each branch, respectively, by BPSK. It is modulated on different carriers to form a transmission signal; the signal passes through a Gaussian white noise channel, and a certain frequency offset noise is added at the same time to reach the receiving end; the receiving end uses correlated demodulation, and after despreading, the error rate is counted. The data shows that under different distances, the frame loss rate of the data link is different. The frame loss rate in the 500 m range is about 1%, and the frame loss rate in the 2 km range is about 2.3%. The results show that the real-time performance of the data link communication system in this paper has been greatly improved.

Design and Implementation of a Real-time Publish/Subscribe Middleware

2019 ◽  
Vol 12 (6) ◽  
pp. 513-518
Author(s):  
Pengyi Zheng
Keyword(s):  
Distributed Systems ◽  
Real Time ◽  
Large Scale ◽  
Data Communication ◽  
Distributed Applications ◽  
Functional Requirements ◽  
Performance Guarantee ◽  
The Real ◽  
Time Performance ◽  
Time Requirements

Background:Middleware has been widely adopted as an efficient approach to facilitate the development process of large-scale distributed systems. Although this approach can achieve simplified system design and reduced time consumption, it has a strong demand for real-time task processing and data transmitting. Traditional middleware, which lacks the real-time performance guarantee mechanism, cannot be adopted by the distributed systems with strict time restrictions.Methods:In order to meet the real-time requirements of distributed systems, the functional requirements of middleware are studied, and a real-time publish/subscribe middleware is designed and implemented in this paper. A hierarchical design is adopted to build this middleware from a model layer, a communication layer and a support layer. The middleware has the data synchronization on distributed objects, Ethernet-based publish/subscribe mechanism and the real-time performance guarantee mechanism.Results:Experiments show that the proposed middleware satisfies the needs of distributed applications, and ensures that the end-to-end data communication delay is less than 1 millisecond, which meets the real-time requirements of data transmission in distributed systems.Conclusion:In this paper, we design and implement a real-time middleware based on the publish/ subscribe mechanism.

Single Depth View Based Real-Time Reconstruction of Hand-Object Interactions

2021 ◽  
Vol 40 (3) ◽  
pp. 1-12
Author(s):  
Hao Zhang ◽  
Yuxiao Zhou ◽  
Yifei Tian ◽  
Jun-Hai Yong ◽  
Feng Xu
Keyword(s):  
Real Time ◽  
Synthetic Data ◽  
Real Data ◽  
Depth Image ◽  
Real Time System ◽  
The Real ◽  
Time Performance ◽  
Contact Constraint ◽  
Object Shapes ◽  
Object Interactions

Reconstructing hand-object interactions is a challenging task due to strong occlusions and complex motions. This article proposes a real-time system that uses a single depth stream to simultaneously reconstruct hand poses, object shape, and rigid/non-rigid motions. To achieve this, we first train a joint learning network to segment the hand and object in a depth image, and to predict the 3D keypoints of the hand. With most layers shared by the two tasks, computation cost is saved for the real-time performance. A hybrid dataset is constructed here to train the network with real data (to learn real-world distributions) and synthetic data (to cover variations of objects, motions, and viewpoints). Next, the depth of the two targets and the keypoints are used in a uniform optimization to reconstruct the interacting motions. Benefitting from a novel tangential contact constraint, the system not only solves the remaining ambiguities but also keeps the real-time performance. Experiments show that our system handles different hand and object shapes, various interactive motions, and moving cameras.

Application of the Real-Time EtherCAT Technology in Wind Power Control System

2012 ◽  
Vol 580 ◽  
pp. 155-159
Author(s):  
Xiang Ming Wang ◽  
Jin Chao Wang ◽  
Dong Hua Sun
Keyword(s):  
Control System ◽  
Real Time ◽  
Wind Power ◽  
High Speed ◽  
Communication Protocol ◽  
Data Communication ◽  
Data Acquisition System ◽  
Slave System ◽  
The Real ◽  
Wind Power System

In this paper, the real-time EtherCAT technology is introduced in detail, which including operating principle, communication protocol and the superiority performance of EtherCAT i.e. synchronicity, simultaneousness and high speed. To show how to design a slave system that considering the characteristics of application, the method of developing systems based no EtherCAT technology are proposed. Finally, a data acquisition system based on EtherCAT technology is designed. Application of EtherCAT technology can improve the real-time characteristics of data communication in wind power system.

Single Chip Microcomputer Cluster Management

2014 ◽  
Vol 933 ◽  
pp. 584-589
Author(s):  
Zhi Chun Zhang ◽  
Song Wei Li ◽  
Wei Ren Wang ◽  
Wei Zhang ◽  
Li Jun Qi
Keyword(s):  
Real Time ◽  
Management System ◽  
Large Scale ◽  
Fault Tolerant ◽  
Single Chip ◽  
Single Chip Microcomputer ◽  
Cluster Management ◽  
The Real ◽  
Time Performance ◽  
Operational Phase

This paper presents a system in which the cluster devices are controlled by single-chip microcomputers, with emphasis on the cluster management techniques of single-chip microcomputers. Each device in a cluster is controlled by a single-chip microcomputer collecting sample data sent to and driving the device by driving data received from the same cluster management computer through COMs. The cluster management system running on the cluster management computer carries out such control as initial SCM identification, run time slice management, communication resource utilization, fault tolerance and error corrections on single-chip microcomputers. Initial SCM identification is achieved by signal responses between the single-chip microcomputers and the cluster management computer. By using the port priority and the parallelization of serial communications, the systems real-time performance is maximized. The real-time performance can be adjusted and improved by increasing or decreasing COMs and the ports linked to each COM, and the real-time performance can also be raised by configuring more cluster management computers. Fault-tolerant control occurs in the initialization phase and the operational phase. In the initialization phase, the cluster management system incorporates unidentified single-chip microcomputers into the system based on the history information recorded on external storage media. In the operational phase, if an operation error of reading and writing on a single-chip microcomputer reaches a predetermined threshold, the single-chip microcomputer is regarded as serious fault or not existing. The cluster management system maintains accuracy maintenance database on external storage medium to solve nonlinear control of specific devices and accuracy maintenance due to wear. The cluster management system uses object-oriented method to design a unified driving framework in order to enable the implementation of the cluster management system simplified, standardized and easy to transplant. The system has been applied in a large-scale simulation system of 230 single-chip microcomputers, which proves that the system is reliable, real-time and easy to maintain.

Switching filtering method for interactive systems

2019 ◽  
Vol 233 (10) ◽  
pp. 1340-1350
Author(s):  
Junyi Hou ◽  
Lei Yu ◽  
Yifan Fang ◽  
Shumin Fei
Keyword(s):  
Real Time ◽  
Subjective Evaluation ◽  
Objective Evaluation ◽  
Interactive Systems ◽  
Interactive System ◽  
The Real ◽  
Noise Interference ◽  
Filtering Method ◽  
Time Performance ◽  
Filtering Effect

Aiming at the problem that the mixed noise interference caused by the mixed projection noise system is not accurate and the real-time performance is poor, this article proposes an adaptive system switching filtering method based on Bayesian estimation switching rules. The method chooses joint bilateral filtering and improved adaptive median filtering as the filtering subsystems and selects the sub-filtering system suitable for the noise by switching rules to achieve the purpose of effectively removing noise. The simulation experiment was carried out by the self-developed human–computer interactive projection image system platform. Through the subjective evaluation, objective evaluation, and running time comparison analysis, a better filtering effect was achieved, and the balance between the filtering precision and the real-time performance of the interactive system was well obtained. Therefore, the proposed method can be widely applied to various human–computer interactive image filtering systems.

Hardware-in-the-loop simulation for real-time software verification of an autonomous underwater robot

2016 ◽  
Vol 4 (3) ◽  
pp. 163-181
Author(s):  
Pouria Sarhadi ◽  
Reza Nad Ali Niachari ◽  
Morteza Pouyan Rad ◽  
Javad Enayati
Keyword(s):  
Software Engineering ◽  
Real Time ◽  
Autonomous Systems ◽  
Systems Design ◽  
Development Stage ◽  
Underwater Robot ◽  
Real Time System ◽  
Content Type ◽  
The Real ◽  
Time Performance

Purpose The purpose of this paper is to propose a software engineering procedure for real-time software development and verification of an autonomous underwater robotic system. High performance and robust software are one of the requirements of autonomous systems design. A simple error in the software can easily lead to a catastrophic failure in a complex system. Then, a systematic procedure is presented for this purpose. Design/methodology/approach This paper utilizes software engineering tools and hardware-inthe-loop (HIL) simulations for real-time system design of an autonomous underwater robot. Findings In this paper, the architecture of the system is extracted. Then, using software engineering techniques a suitable structure for control software is presented. Considering the desirable targets of the robot, suitable algorithms and functions are developed. After the development stage, proving the real-time performance of the software is disclosed. Originality/value A suitable approach for analyzing the real-time performance is presented. This approach is implemented using HIL simulations. The developed structure is applicable to other autonomous systems.

scholarly journals Review and Comparison of Path Tracking Based on Model Predictive Control

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1077 ◽  
Author(s):  
Guoxing Bai ◽  
Yu Meng ◽  
Li Liu ◽  
Weidong Luo ◽  
Qing Gu ◽  
...  
Keyword(s):  
Model Predictive Control ◽  
Real Time ◽  
Predictive Control ◽  
Path Tracking ◽  
Error Model ◽  
The Real ◽  
Time Performance ◽  
Reference Path ◽  
Reference Velocity ◽  
Positioning Errors

Recently, model predictive control (MPC) is increasingly applied to path tracking of mobile devices, such as mobile robots. The characteristics of these MPC-based controllers are not identical due to the different approaches taken during design. According to the differences in the prediction models, we believe that the existing MPC-based path tracking controllers can be divided into four categories. We named them linear model predictive control (LMPC), linear error model predictive control (LEMPC), nonlinear model predictive control (NMPC), and nonlinear error model predictive control (NEMPC). Subsequently, we built these four controllers for the same mobile robot and compared them. By comparison, we got some conclusions. The real-time performance of LMPC and LEMPC is good, but they are less robust to reference paths and positioning errors. NMPC performs well when the reference velocity is high and the radius of the reference path is small. It is also robust to positioning errors. However, the real-time performance of NMPC is slightly worse. NEMPC has many disadvantages. Like LMPC and LEMPC, it performs poorly when the reference velocity is high and the radius of the reference path is small. Its real-time performance is also not good enough.

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