基于元动作理论的驱传系统数字孪生模型构建

针对面向实际工程应用的数字孪生技术,探索了基于元动作理论的机电设备驱传系统数字孪生体模型框架的构建及其关键技术。阐述了从零部件到元动作理论的历史渊源,对元动作理论的相关概念及其引入数字孪生技术的原由进行了介绍,对比了其与传统方法的不同,在此基础上从元动作的优势和特点出发,以元动作理论为底层架构,将其引入驱传系统的数字孪生技术。提出驱传系统数字孪生体的内涵并详细定义了单元级、链级、系统级孪生体3个层次,搭建了基于元动作理论的驱传系统数字孪生体的五维框架。以某型号数控转台的驱传系统为例构建了实时监控数字孪生系统实例,给出了数字孪生技术的应用框架,验证了该数字孪生模型具有一定的实际意义与工程应用价值。

FLIGHT DELAY STATE-SPACE MODEL BASED ON GENETIC EM ALGORITHM

Flight delay prediction remains an important research topic due to dynamic nature in flight operation and numerous delay factors.Dynamic data-driven application system in the control area can provide a solution to this problem.However,in order to apply the approach,a state-space flight delay model needs to be established to represent the relationship among system states,as well as the relationship between system states and input/output variables.Based on the analysis of delay event sequence in a single flight,a state-space mixture model is established and input variables in the model are studied.Case study is also carried out on historical flight delay data.In addition,the genetic expectation-maximization（EM）algorithm is used to obtain the global optimal estimates of parameters in the mixture model,and results fit the historical data.At last,the model is validated in Kolmogorov-Smirnov tests.Results show that the model has reasonable goodness of fitting the data,and the search performance of traditional EM algorithm can be improved by using the genetic algorithm.

Simulation on model predictive control for PMSM drive system based on double extended state observer

A novel double extended state observer(DESO)based on model predictive torque control(MPTC)strategy is developed for three-phase permanent magnet synchronous motor(PMSM)drive system without current sensor.In general,to achieve high-precision control,two-phase current sensors are necessary for successful implementation of MPTC.For this purpose,two ESOs are used to estimate q-axis current and stator resistance respectively,and then based on this,d-axis current is estimated.Moreover,to reduce torque and flux ripple and to improve the performance of the torque and speed,MPTC strategy is designed.The simulation results validate the feasibility and effectiveness of the proposed scheme.

ACTIVE VIBRATION CONTROL OF A CANTILEVER BEAM USING PIEZOELECTRIC SENSORS AND ACTUATORS

The topic of vibration control with distributed actuators has been the subject of many researches. This paper is concerned with the vibration control of a cantilever beam equipped with piezoelectric ceramics as sensors and actuators. One piezoelectric ceramic is bonded to the structure and provides control input for the structure, while the other piezoelectric ceramic provides the feedback signal. An approach to identification and control is presented. Observation spillover is eliminated by prefiltering the sensor data. A procedure used to determine actuator and sensor location, is discussed based on the modes to be controlled. Finally, the experimental results are presented to verify the proposed method.

Analyzing Cavitation Caused by Metal Particles in the Transaxle： Application of High Quality Assurance CAE Analysis Model

This paper focuses on a strategic improving quality of＂high quality assurance CAE （computer aided engineering） analysis model＂ to be used in development design. The authors present a case oftransaxle oil seal leakage in automotive drive trains, a technical reliability problem that generates bottlenecks for auto manufacturers around the world. The application of this model is used to analyze cavitation caused by the metal particles （foreign matter） generated through transaxle wear. This analyzing method primarily uses numerical simulation （CAE） to clarify the technological mechanism generating oil leaks as a result of foreign metallic substances entering oil seals in the drive train. Quality improvement using this CAE analyzing method was verified by successfully applying it to the technological problem of development design bottlenecks at auto manufacturers.

Drivers of Change, Threats and Barriers to the Conservation of Biodiversity in Traditional Agricultural Systems

People and nature are working in tandem to reduce the integrity of traditional agricultural systems. The paper highlighted the drivers of change acting on traditional agricultural landscapes including the threats and barriers hindering biodiversity conservation. The drivers of change are： modem agriculture, tourism, education and outmigration and climate change. The threats are encroachment and land-use change, pollution, replacement of traditional varieties and erosion of indigenous knowledge systems and practices. The barriers to biodiversity conservation include the incapacity of farmers to respond to pressures affecting their traditional farming systems, absence of methodologies for integrating traditional and modem knowledge in biodiversity conservation and the multi-functionality of traditional agriculture not fully captured by the market. The conservation framework to guide stakeholders for in-situ management of biodiversity includes niche market development, revenue generation and cultural restoration. The study made use of data collected during the series of workshops conducted in 2005-2007 covering the Ifugao Rice Terraces of the Philippines. Secondary data from other traditional agricultural systems were integrated to enrich the discussion and write-up of this paper.

Sensorless Control of Switched Reluctance Motor Drive Systems

This paper presents a sliding mode observer for sensorless operation of SRM （switched reluctance motor） drive. Design of such an observer depends mainly on the nonlinear model of SRM. In this technique, neither extra hardware nor huge memory space are not required but it only requires active phase measurements. Furthermore, PI （proportional integral） and adaptive FLPI （fuzzy logic PI） controllers are suggested to operate individually along with the SMO （sliding mode observer） to cover a full speed range of sensorless controller. Both controller schemes operate in PWM （pulse width modulation） control mode. The proposed observer is implemented and tested using a digital signal processor. All results obtained with both simulation and experimental investigations corroborate the superior performance of the adaptive fuzzy logic controller （FLPI） when compared with those of PI controller.

Megabots Team： A Team for the Category Sumo Autonomous 3 kg

This paper deals with a method for building a mobile robot in order to transform the material into a practical guide for beginners in the study of mobile robotics. The project is divided into layers that can define the topics related to the areas of knowledge that will be used in carrying out the project. These areas are the mechanics, electronics and computing system. The mobile robot named Fable was developed accordingly to this method. It is composed by two active wheels, each one driven by DC motor with a high torque and a transmission system containing two spur gears. It has three sonars for detection of the opponent and two infrared sensors to detect a line and an Arduino Uno board is used to control all the actions of the robot.

Design of a Hardware/Software FPGA-Based Driver System for a Large Area High Resolution CCD Image Sensor

A hardware/software field programmable gate array （FPGA）-based driver system was proposed and demonstrated for the KAF-39000 large area high resolution charge coupled device （CCD）. The requirements of the KAF-39000 driver system were analyzed. The structure of ＂microprocessor with application specific integrated circuit （ASIC） chips＂ was implemented to design the driver system. The system test results showed that dual channels of imaging analog data were obtained with a frame rate of 0.87frame/s. The frequencies of horizontal timing and vertical timing were 22.9MHz and 28.7kHz, respectively, which almost reached the theoretical value of 24 MHz and 30kHz, respectively.

Theoretical analysis of output speed of multi-pump and multi-motor driving system

A theory for multi-pump and multi-motor hydraulic systems is presented in this paper based on the analysis of the advantages and disadvantages of the popular hydraulic transmission and the double-stator motor(pump).By taking the single-acting fixed displacement multi-pump and multi-motor driving system as an example,the output speeds in a variety of connections of this novel hydraulic transmission are analyzed theoretically.This research work lays a theoretical foundation for the study of the multi-pump and multi-motor driving system and for the design of the system principle diagram.