主被动磁悬浮高速转子系统的自动平衡控制

针对主被动磁悬浮转子高速旋转时质量不平衡和被动磁轴承磁中心的偏移导致的同频振动力问题,提出了一种基于位移陷波加前馈补偿的自动平衡控制方法。首先,在转子为零位移控制状态下提取控制电流的同频成分,计算获得与被动磁轴承磁中心偏移相关的参变量;然后,在额定转速下设计通用陷波器以消除同频电流,前馈补偿主动磁轴承、被动磁轴承位移负刚度力和被动磁轴承磁中心偏移力,使主被动磁轴承的同频输出力为零,实现了转子绕惯性中心旋转。对提出的方法进行了仿真和实验验证并与仅补偿质量不平衡的算法进行了对比。仿真结果显示:提出的方法的同频磁轴承力减小到了只进行质量不平衡补偿算法的6%;实验结果显示:同频振动加速度减小到只进行质量不平衡补偿算法的23.3%。仿真和实验验证了该方法的有效性,表明该方法对同频振动抑制效果显著,实现了转子的自动平衡控制。

基于PLC的液压自动平衡控制系统的设计

针对海上作业、高空作业、移动设备等工作情况下工作表面发生倾斜的复杂情况,设计一种基于PLC的液压自动平衡控制系统。系统由三菱FX3U系列PLC、三菱GS2107-WTBD人机界面、倾角传感器和液压泵站等组成。通过倾斜传感器与PLC间进行Modbus-RTU通信,实现PLC控制工作表面自动平衡。实验证明:系统能快速、准确地实现自动调平。

聚酯生产中半直纺工艺的动平衡控制的改进

聚酯生产的半直纺工艺是指PET生产的熔体一部分用于短纤维纺丝,一部分用于聚酯切片。而这个过程中纺丝压力控制和切粒机的转速控制是稳定生产的关键。本文提出的方案就是将纺丝压力控制和切粒机转速控制设计为相互影响的动平衡控制,从而解决了生产中短丝更换纺丝泵引起压力变化造成切粒机放流,更换切粒机时造成纺丝增压泵停泵的矛盾,稳定了PET和短纤维两套生产装置的正常生产。

液压自动平衡控制系统设计

海上作业及移动设备等特殊工况下工作台表面在外力作用下发生倾斜,影响工作效率及可靠性,对此基于PLC设计了自动液压平衡控制系统。该系统由PLC、人机交互界面、传感器及液压泵站组成。传感器对工作面倾角进行监测,通过Modbus-RTU将检测结果传递到PLC进行分析计算,根据分析结果对液压系统进行控制,实现工作面自动平衡。由测试结果可知:该液压自动平衡系统响应速度快,调整精准,具有良好的应用效果。

加热炉的流路自动平衡控制

在实际生产过程中 ,由于种种原因 ,加热炉各炉管的出口温度会不尽相同。这样必然会影响到加热炉的操作效率 ,甚至更会影响人员及设备安全。对石油化工生产过程中经常用到的多通路加热炉各炉管操作中的主要影响因素进行分析 。

自升式海洋平台自动平衡控制的研究

自行研制了基于 PL C的自动平衡控制装置和控制程序 ,应用在辽海试采 2号海洋平台升降装置的技术改造中 .实用结果表明 ,这种平台自动平衡控制装置和控制程序 ,能够实现八种不同倾斜姿态的校正 ,保证在平台升降过程中 ,横纵倾斜小于 0 .3°。

轧辊磨床测量监控及砂轮平衡系统的修整方法研究

砂轮对于磨床来说是磨削过程中重要的组成部分,砂轮磨削前的修整情况直接决定了工件的表面质量以及能否满足工艺要求,实现砂轮恒线速运行是提高磨削效率和工件表面质量的关键。本文涉及一种采用安装在尾架上的测量机构,实时自动测量砂轮的装置及砂轮负载监控修整的理念方法,通过改变砂轮转速从而达到恒线速的方式来进行修磨实现被加工面轮廓外形的精度控制。

时域脉冲平衡零拍探测器的高精度自动平衡

时域脉冲平衡零拍探测器能够直接对光场量子态的正交分量进行测量,是连续变量量子密钥分发系统的核心测量器件,其测量精度与密钥分发系统的额外噪声及安全密钥速率密切相关.本文理论分析了探测器双臂不平衡对测量精度的影响,并实验设计、研制了双臂可精确自动平衡的时域脉冲平衡零拍探测器.通过高精度控制探测器一臂的光纤圆环曲率半径,实现了光纤内部光场强度的精密衰减,进而获得了探测器的精确自动平衡.实验测试结果表明时域平衡零拍探测器双臂具有10^(-5)以上的平衡精度,能够长时间稳定运行,有效避免了探测器的输出电压进入非线性区或饱和区.该探测装置可应用于连续变量量子密钥分发系统,有效降低由于量子态信号探测过程引入的额外噪声,提高系统的长期稳定性.

烘丝机排潮管路负压自动平衡系统的研究

在烟草生产工艺流程中,制丝生产环节中的烟丝润与烘是一个关键工艺流程,该工艺流程的好坏直接影响到后续烟丝的流程。目前烟丝烘干是通过排潮系统实现调节的,排潮管路通过风机和除尘袋实现排潮,但是由于烟丝烘干中水蒸汽含水率高,导致除尘袋易潮,灰尘容易堵导致排潮管路的负压波动,影响排潮效果,目前是通过人工检查和人工调节风门来实现对负压的管控,比较费时费力。本文论述的一种排潮管路负压自动平衡控制系统,该系统通过对负压管道的通风实时监控,实时反馈调节风机频率和风机出口风门开度,保证排潮管路负压自动平衡,提升了效率。

PLC与旋转编码器在12m三星辊平衡系统的应用

叙述如何采用PLC控制器和增量型旋转编码器实现12mm三星辊的自动平衡控制。

整体压气机叶轮加工工艺研究

文章就整体压气机叶轮加工工艺过程中的五轴叶型铣削、超速预过载、动平衡精度控制3个工序中存在的工艺难点进行论述,通过采用与机床参数相匹配的数控程序刀轨、简单可行的超速装夹方式、合理的工艺路线编排,为解决以上3个工序中存在的难点提供了一套行之有效的工艺解决方案。

A Study on PC/104 Embedded Automatic Balancing Control System

In this paper,an embedded real-time control system for automatic rotor balancing was studied.Benefiting from the modular design,this system can be easily re-constituted or expanded under different working conditions.The special designed hardware resists harsh environment.As an embedded application,it was very important to save system consumptions on both hardware and software,so the algorithms for unbalance vibration identification and attenuation were deduced,meantime a unified fast algorithm structure was achieved through the geometric analysis.Based on this structure,the signal processing algorithm was tested by an open data source,while the control algorithm was simulated using a basic rotor model,and then connected to a hyper gravity machine running online auto-balancing.The result confirms that the unbalancing vibration is effectively restrained.

Combining Market-Based Control with Distribution Grid Constraints when Coordinating Electric Vehicle Charging

The charging of electric vehicles(EVs) impacts the distribution grid, and its cost depends on the price of electricity when charging. An aggregator that is responsible for a large fleet of EVs can use a market-based control algorithm to coordinate the charging of these vehicles, in order to minimize the costs. In such an optimization, the operational parameters of the distribution grid, to which the EVs are connected, are not considered. This can lead to violations of the technical constraints of the grid(e.g., undervoltage, phase unbalances); for example, because many vehicles start charging simultaneously when the price is low. An optimization that simultaneously takes the economic and technical aspects into account is complex, because it has to combine time-driven control at the market level with eventdriven control at the operational level. Diff erent case studies investigate under which circumstances the market-based control, which coordinates EV charging, conflicts with the operational constraints of the distribution grid. Especially in weak grids, phase unbalance and voltage issues arise with a high share of EVs. A low-level voltage droop controller at the charging point of the EV can be used to avoid many grid constraint violations, by reducing the charge power if the local voltage is too low. While this action implies a deviation from the cost-optimal operating point, it is shown that this has a very limited impact on the business case of an aggregator, and is able to comply with the technical distribution grid constraints, even in weak distribution grids with many EVs.

Dynamic balancing with rotating radial electromagnetic force

A method of producing rotating radial electromagnetic force with a separable structure is proposed, and an experimental model was designed on which open loop vibration control experiments were carried out. Experimental results prove that the electromagnetic force designed has a constant magnitude and an uniform speed, and the idea of using an electromagnetic force as an active control in automatic balancing is correct in principle, and practicable in engineering.

Athletes who train on unstable compared to stable surfaces exhibit unique postural control strategies in response to balance perturbations

Background:Athletes have been shown to exhibit better balance compared to non-athletes(NON).However,few studies have investigated how the surface on which athletes train affects the strategies adopted to maintain balance.Two distinct athlete groups who experience different types of sport-specific balance training are stable surface athletes(SSA) such as basketball players and those who train on unstable surfaces(USA) such as surfers.The purpose of this study was to investigate the effects of training surface on dynamic balance in athletes compared to NON.Methods:Eight NON,eight SSA,and eight USA performed five 20-s trials in each of five experimental conditions including a static condition and four dynamic conditions in which the support surface translated in the anteroposterior(AP) or mediolateral(ML) planes using positive or negative feedback paradigms.Approximate entropy(Ap En) and root mean square distance(RMS) of the center of pressure(Co P) were calculated for the AP and ML directions.Four 3 × 5(group × condition) repeated measures ANOVAs were used to determine significant effects of group and condition on variables of interest.Results:USA exhibited smaller Ap En values than SSA in the AP signals while no significant differences were observed in the ML Co P signals.Generally,the negative feedback conditions were associated with significantly greater RMS values than the positive feedback conditions.Conclusion:USA exhibit unique postural strategies compared to SSA.These unique strategies seemingly exhibit a direction-specific attribute and may be associated with divergent motor control strategies.

Study on fuzzy control of dynamic equalization based on state prediction

A new method of using dynamic equalization technology to realize the maximum energy storage utilization was presented to overcome the influence of the disaccord among units of series super capacitor （SC） bank and ensure that the units could work safely. By considering in combination with the high specific power, low working voltage, wide voltage working range and noulinear external characteristics, we present constant duty ratio pulse frequency modulation mode and fuzzy control method based on state prediction in the active equalization circuit and accomplish the software and hardware design for the equalization system. The simulation analysis and experiment results of constant current muhi-cycle and variable current multi-cycle charge-discharge process verify the validity of the design.

Two types of coaxial self-balancing robots

Two types of coaxial self-balancing robots(CSBR)were proposed,one can be used as a mobile robot platform for parts transporting in unmanned factory or as an inspector in dangerous areas,and the other can be used as a personal transporter ridden in cities.Mechanical designing and control structures as well as control strategies were described and compared in order to get a general way to develop such robots.A state feedback controller and a fuzzy controller were designed for the robot using DC servo motors and the robot using torque motors,respectively.The experiments indicate that the robots can realize various desired operations smoothly and agilely at the velocity of 0.6 m/s with an operator of 65 kg.Furthermore,the robustness of the controllers is revealed since these controllers can stabilize the robot even with unknown external disturbances.

Methods for Calculating Activation Energies of Ideal Gases

The previous paper Ref. [1] showed how to calculate activation energies for ideal gas reactions from the CDF （cumulative distribution function） of the MBD （Maxwell Boltzmann Distribution） and the heat capacity data of the components. The results presented here show comparisons of activation energies of four ideal gases calculated in that way with those calculated from the ND （Normal Distribution） and its CDF. The evaluation of the CDF for the MBD in Ref. [1] required extensive numerical integrations for each substance. In this paper this method of calculating activation energies is generalised, by showing the CDF is a unique function, independent of temperature and composition, enabling the CDF to be presented graphically or in tabular form. These activation energies are compared to those calculated from the ND and its CDF. The MBD is related to the ND because it has a generating function which is shown here to have the simple form （1-kT）-1.5. The activation energies obtained from the CDF of the ND are shown to agree ca. 5-7% with those obtained directly from the MBD. Because existing thermodynamic treatments are based on average properties, they cannot give either a complete account of thermodynamic controlled and kinetic controlled equilibrium states or explain transitions between them. Complete treatments must include effects from the MBD which are the causes of kinetic controlled equilibrium. The basis for a complete treatment is outlined, which includes the standard deviations and activation energies.

Controlling Nonlinear Dynamics in Continuous Crystallizers

Crystallization is used to produce vast quantities of materials. For several applications, continuous crystallization is often the best operation mode because it is able to reproduce better crystal size distributions than other operation modes. Nonlinear oscillation in continuous industrial crystallization processes is a well-known phenomenon leading to practical difficulties such that control actions are necessary. Nonlinear oscillation is a consequence of the highly nonlinear kinetics, different feedbacks between the variables and elementary processes taking place in crystallizers units, and the non-equilibrium thermodynamic operation. In this paper the control of a continuous crystallizer model that displays oscillatory behavior is addressed via two practical robust control approaches： （i） modeling error compensation, and （ii） integral high order sliding mode control. The controller designs are based on the reduced-order model representation of the population balance equations resulting after the application of the method of moments. Numerical simulations show good closed-loop performance and robustness properties

Control of Doubly Fed Induction Generator under Unbalanced Voltages for Reduction of Torque Pulsation

The unbalanced voltages cause negative effects on the doubly fed induction generator （DFIG） sucn as torque pulsation,and increased stator current. Based on the symmetrical component theory, the torque pulsation is the consequence of the interaction of stator and rotor currents of different sequences. This paper presents a control technique to reduce the effect of unbalanced voltages on the DFIG in wind energy conversion systems. The negative sequence stator voltage is derived from the unbalanced three phase stator voltages. The compensated rotor voltage in terms of the derived negative sequence stator voltage and slip which minimizes the negative stator and rotor currents is proposed. The results from the simulation of control system with steady state model and dynamic model of the DFIG show that additional control loop with compensated voltage can significantly reduce torque and reactive power pulsations.