Finite element analysis of V-ribbed belt/pulley system with pulley misalignment using a neural-network-based material model

Pulley misalignment limits the performance of V-ribbed belt/pulley system as it relates to rib load-sharing and contact pressure distribution for multiple rib belts required in high torque demands of modern automotive applications. In this paper, a three-dimensional dynamic finite element model is built to evaluate the effects of pulley misalignment. The model consists of a pulley and a segment of V-ribbed belt in contact with the pulley. A material model of belt, including rubber compound and reinforcing cord is developed. Multiple rubber layers are each considered hyperelastic with distinct material characterization parameters. A novel neural-network-based hyperelastic material model is implemented to represent properties of nonlinear elastic belt-rib compound. The models are implemented in the commercial code ABAQUS/Explicit to simulate the misalignment of the belt–pulley system. The developed model is first validated by experimental measurements of pulley lateral force due to misalignment. Also, three common types of misalignment in the belt–pulley system are analyzed and results are presented.     

Parametric instability of belts: theory and experiments

In this paper, the dynamic stability of a power transmission belt excited by an eccentric pulley is investigated. A theoretical model is developed to predict the belt response: simply supported boundary conditions are considered, neglecting the pulley curvature, and including the effect of the lower belt span. The transverse displacement field is expanded into sine series and the Galerkin method is applied to reduce the partial differential equation (PDE) into a set of ordinary differential equations. In order to forecast the belt response, the elastic characteristics only of the belt must be provided to the theoretical model. An experimental investigation is performed on a belt-pulley system with a pulley eccentricity; a laser displacement transducer is used to measure the transverse displacement. The combination of a direct and a parametric excitation is analyzed in detail. Interesting post-critical nonlinear dynamic behaviors are found: sub-harmonic responses and quasi-periodic motions seem to coexist, depending on the initial conditions. Experiments confirm the numerical results, thus validating the present theoretical model.     

Unbalance compensation for AMB systems with input delay: An output regulation approach

Unbalance compensation is an important technique for reducing rotor vibration in high speed rotating machines caused by residual rotor unbalance. As rotating machines in remote applications aim for higher speeds to gain efficiency and to reduce footprint, there is a need to extend the unbalance compensation techniques to active magnetic bearing (AMB) systems with delays in the control loop. This paper investigates the unbalance compensation problem for AMB systems with input delays. An unbalance compensation method is developed based on a solution to the output regulator problem for systems with input delay. The proposed unbalance compensation method is verified through simulation, and experimentally validated on an AMB test rig.     

轮-带驱动系统稳态周期响应谐波平衡分析

研究含有单向离合器、两滑轮及附件的轮-带驱动系统稳定稳态周期响应.通过单向离合器连接从动轮与附属系统,并计入传送带的横向振动的影响,导出了由偏微分-积分方程与分段常微分方程组成的连续-离散型非线性耦合方程组.利用Galerkin方法将连续非线性方程组截断为一组非线性常微分方程组,再运用谐波平衡法得到轮-带驱动系统耦合非线性振动的稳态响应.通过比较有无单向离合器装置的系统稳定稳态幅频响应曲线,研究了单向离合器对驱动系统以及轮-带系统非线性动态特性的影响.并首次研究了高频激励下轮-带系统的稳态响应.最后,运用Runge-Kutta方法对比验证了基于谐波平衡法得到的稳态响应.     

煤矿双电机驱动带式输送机的能耗建模与参数辨识

带式输送机运行过程中的能耗与原煤运量和带速关系密切,根据运量优化带速,对于输送机节能运行有重要意义.本文面向煤矿双电机驱动带式输送机节能运行,研究能耗建模和参数辨识方法.首先,根据双电机驱动模式,建立基于电机动态模型的输送机能耗模型;然后,根据电机电流、转速和运量的测量数据,建立基于磁链观测器和递推最小二乘的参数辨识方法;最后,通过仿真实验说明所提方法的有效性.     

A computer simulation model for studying the performance of coordinate measuring machines

The increasing trend toward computer-integrated manufacturing (CIM) in today's industry created a need for an effective process control. The objective of the inspection process is not only preventing shipment of defective parts but also providing a feedback to keep the manufacturing process in control. Through data processing capability, speed, and flexibility of operation, coordinate measuring machines (CMMs) play an important role for computer-integrated manufacturing (CIM). This paper introduces coordinate measuring machines and studies their performance. A computer simulation method for studying the performance of such machines working in a production line is developed. In this paper, CMM performance is measured by its speed and flexibility in performing measurements. In flexible manufacturing systems (FMS), CMMs serve as the inspection work station where arrival time of parts to be measured vary according to the flow of operations. The developed simulation model provides information about the machine, scheduled time for parts to be measured, and delay time for the measuring process.     

Multiple-page mapping artificial neural network algorithm used for constant tension control

Constant tension control is widely required in industrial applications such as paper machines, coating machines, rewinding and unwinding machines. In a metal film coating machine, which is a multi-input multi-output system, speed and tension have cross coupling and thus desired speed and tension responses are difficult to achieve by applying conventional analogue proportional-plus-integral (PI) control. This paper introduces a multiple-page mapping artificial neural network with back-propagation training algorithm. This method can successfully decouple the speed and tension control loops and both loops can operate quasi-independently. It overcomes the disadvantages of traditional PI control systems. To handle the variation of the rewinding roll diameter, multiple pages of neural networks are applied. Some simulation results show the effectiveness of this control algorithm.     

Effect of belt transport speed and other factors on belt mistracking

Rubber rollers and conveyor belts transport flexible sheet-type media. With high-speed belt transporting systems such as mail sorters, demand for an increase in speed may cause the belt to come off. Therefore, we have examined the effects of belt transport speed and other factors that may cause belt mistracking for a basic belt conveyor system, consisting of one flat belt and two crown-face rollers. Experiments were conducted and we have formulated an experimental expression of the amount of belt mistracking using the roller misalignment parameters. As for transport speed, a speed increase did not enlarge belt mistracking. This tendency was explained by applying the cornering force of automotive engineering. In parallel, simulation was conducted using commercial motion system analysis software. The qualitative tendencies of the belt mistracking from simulation and experiment were in good agreement and factorial effects were clarified for ten parameters. Quantitatively, when axial load on rollers and other parameters were made equal, the belt mistracking according to simulation was generally in agreement with the experimental value.     

基于PLC的胶带输送机综合保护系统的研究

针对现有大型矿井胶带输送机保护种类不全、可靠性低等问题,设计了一种胶带输送机综合保护系统,分析了胶带输送机的常见故障类型,介绍了系统的硬件结构和软件设计,确定了胶带速度、温度、烟雾、跑偏等故障的检测方法。该保护系统采用PLC高速计数器对系统传感器频率量进行采集和处理,实现了对胶带输送机故障的实时检测和综合判断,降低了误动率。     

Workspace analysis of a 6-DOF cable-driven parallel robot considering pulley bearing friction under ultra-high acceleration

Cable robots can generate high velocities and accelerations due to the very small inertia of the end-effector. Therefore, CDPRs have been used widely in special industrial applications requiring high dynamics. However, the high acceleration generated affects the wrench-feasible workspace of a CDPR system significantly. In addition, as a pulley rotates, the frictional force at the pulley bearing disturbs the motion, changes the cable tensions. Thus, pulley bearing friction cannot be neglected in ultra-high acceleration systems where high tensions are imposed. A workspace analysis was carried out for a wrench-feasible condition in a 6-DOF CDPR system considering the pulley bearing friction connected in series. Then, the pulley bearing friction was modeled with the Coulomb friction model including the variation of wrapping angle of pulley and a loss factor. The simulated tension profiles considering pulley bearing friction were in good agreement with data measured with a load cell. And a wrench-feasible workspace analysis under various accelerations was carried out. In conclusion, as the external acceleration was increased, the whole tension was increased and workspaces to exceed available tension occurred in case of 100 m/s². And the pulley bearing force increased or decreased the cable tension because of the direction of the signum function. As a result, the wrench-feasible workspace was changed in the presence of pulley bearing force effects.

     

冶金工业的变频器应用与维护(六) 变频器在金属拉丝中的应用

常见的拉丝机包括直进式、活套式、滑轮式和水箱式几种,在以前通常都采用直流电机或发电机-电动机组(F-D系统)来实现,现在随着工艺技术的进步和变频器的大量普及,变频控制开始在各式拉丝机中大量使用,并可通过PLC来实现拉拔品种设定、操作自动化、生产过程控制、实时闭环控制、自动计米等功能。     

Stresses and deformations of a conveyor power pulley shell under exponential belt tensions

Theoretical analysis of stresses and deformations of the cylindrical shell of a conveyor power pulley under exponential belt loading has been carried out. The present analysis is found to be in good agreement with the experimental results for steel conveyor pulleys. Results using different parameters are computed and obtained in graphical form. They are also in good agreement with those obtained by Siegfried Scholich under equal tight and slack side belt tensions.     

用Boltzmann网络解任务安排问题

本文提出了一种解任务安排问题的Ｂｏｌｔｚｍａｎｎ网络算法，已在Ｔｒａｎｓｐｕｔｅｒ多处理机系统上并行模拟实现，该算法具有优化程度高，运算速度快等特点．     

Extended Kalman filter based speeds estimation of series-connected five-phase two-motor drive system

The multi-phase machines enables independent control of a few number of machines that are connected in series in a particular manner, and the supply is fed from a single voltage source inverter (VSI). The idea was first implemented for a five-phase series-connected two-motor drive system, but is now applicable to any number of phases. The number of series-connected machines is a function of the phase number of VSI. Variable speed induction motor drives without mechanical speed sensors at the motor shaft have the attractions of low cost and high reliability. To replace the sensor, information of the rotor speed is extracted from measured stator currents and voltages at motor terminals. Open-loop estimators or closed-loop observers are used for this purpose. They differ with respect to accuracy, robustness, and sensitivity against model parameter variations. This paper analyses operation of an EKF-based sensorless control of vector controlled series-connected two-motor five-phase drive system with current control in the stationary reference frame. Results, obtained with fixed voltage and fixed frequency supply fed and hysteresis current control, is presented for various operating conditions on the basis of simulation. The purpose of this paper is to report first time, the simulation results on a sensorless control of a five-phase two-motor series-connected drive system using EKF estimator.     

Network virtualization substrate with parallelized data plane

Network virtualization provides the ability to run multiple concurrent virtual networks over a shared substrate. However, it is challenging to design such a platform to host multiple heterogenous and often highly customized virtual networks. Not only high degree of flexibility is desired for virtual networks to customize their functions, fast packet forwarding is also required. This paper presents PdP, a flexible network virtualization platform capable of achieving high speed packet forwarding. A PdP node has multiple machines to perform packet processing for virtual networks hosted in the system. To forward packets in high speed, the data plane of a virtual network in PdP can be allocated with multiple forwarding machines to process packets in parallel. Furthermore, a virtual network in PdP can be fully customized. Both the control plane and data plane of a virtual network run in virtual machines so as to be isolated from other virtual networks. We have built a proof-of-concept prototyping PdP platform using off-the-shelf commodity hardware and open source software. The performance evaluation results show that our system can closely match the best-known packet forwarding speed of software router running in commodity hardware.     

A computational model for static data flow machines

Computer architects have been constantly looking for new approaches to design high-performance machines. Data flow and VLSI offer two mutually supportive approaches towards a promising design for future super-computers. When very high speed computations are needed, data flow machines may be relied upon as an adequate solution in which extremely parallel processing is achieved.

This paper presents a formal analysis for data flow machines. Moreover, the following three machines are considered: (1) MIT static data flow machine; (2) TI's DDP static data flow machine; (3) LAU data flow machine.

These machines are investigated by making use of a reference model. The contributions of this paper include: (1) Developing a Data Flow Random Access Machine model (DFRAM), for first time, to serve as a formal modeling tool. Also, by making use of this model one can calculate the time cost of various static data machines, as well as the performance of these machines. (2) Constructing a practical Data Flow Simulator (DFS) on the basis of the DFRAM model. Such DFS is modular and portable and can be implemented with less sophistication. The DFS is used not only to study the performance of the underlying data flow machines but also to verify the DFRAM model.     

An efficient dictionary machine using hexagonal processor arrays

Dictionary machine is an important VLSI system performing high speed data archival operations. In this paper, we present a design which can efficiently implement dictionary machines in VLSI processor arrays. In order to effectively process the operations of dictionary machine, hexagonal mesh is selected as the host topology in which two different networks for update and query operation are embedded. The proposed design is simple to implement as well as allows high throughput     

QFT在高速线性电机直接驱动平面运动定位控制系统中的应用

研究定量反馈理论(QFT)在高速直线电机直接驱动平面运动定位系统控制中的应用问题.该系统采用三闭环(即电流,速度,位置)串级反馈控制加前馈补偿结构.基于8台不同机器上实际测得的频域特性,所设计的QFT高阶鲁棒控制器可以大大降低该系统在大加速度运动状态下所呈现的谐振不确定性.同时,该控制器对传感器噪声和干扰也具有较好的抑制能力.在最大加速度达到6.8g的给定运动轨迹条件下,通过在批量生产的打线机(用于半导体封装)平面运动定位系统的实验结果证实了该方法的有效性.     

Input shaping reference commands for trajectory following Cartesian machines

This work shows research into how input shaping, a real-time filtering method that is reviewed, affects spatial trajectory following ability for machines that can be modelled as two-orthogonal flexible modes. We prove that input shaping improves the tracking ability of two-dimensional circular and square trajectories for nearly all values of command speed (feedrate) as it is used in numerical controlled machine tools, and high speed coordinate measuring machines. An approximate high feedrate boundary for zero tracking error using input shaping might have been found. Even in the presence of large modelling errors, robust shapers have demonstrated important contour error reduction. This paper also develops a coherent input shaping scheme for the command generator velocity profile that is preferable to shape the single axis position signals.