利用外扰模型前馈控制抑制轧机扭振的应用

建立了轧机的数学模型,分析了轧机扭振的原因,指出轧制电流是决定轧机是否扭振的关键因素.针对安阳钢铁公司中厚板轧机存在扭振现象,通过对扭振的测量、分析,表明在咬钢时会发生扭振.提出了模型前馈控制抑制轧机扭振,模型前馈控制通过建立理想的电机模型,将电流给定观测出并补偿到系统中去,达到抑制轧机扭振的目的;研究表明轧件咬入时的冲击是造成扭振的主要原因,模型前馈控制是抑制轧机扭振的有效方法,在工程中容易实现,而且不受轧机振动频率的影响,可抑制各个频段的振动.     

热轧粗轧机上下辊联合振动的故障处理

宝钢三热轧粗轧机R1上下辊在轧制高硬度钢种时出现轧机振荡,主要是原系统存在两方面的因素导致轧机振荡的加剧：一是R1轧机的转动惯量偏小,咬钢时动态速降大,且原双闭环控制系统存在反应滞后的缺点,使R1轧机在咬钢与加速过程中扭振加剧;二是原系统速度环的截止频率与上下辊及轧制材料组成的联合体的固有频率接近,导致R1粗轧机出现联合共振。通过投入外扰模型前馈控制（SFC）功能减轻了动态速降大的问题,有效抑制了轧机振动;通过对速度环控制参数的分段切换控制,使控制系统的频率与联合体的固有频率错开,保证了R1轧机的稳定运行。     

轧机扭振控制策略与实施(上)

扭振是轧机普遍存在的问题，也是轧机改造中的一个关键问题。轧机在改造后因输出功率和转矩增加，系统动态性能的提高，扭振将为得非常严重。本文结合攀钢1450轧机改造工程，阐述和分析了轧机扭振的计算和抑制方法。     

鞍钢1700中薄板坯连铸连轧(ASP)R1轧机综合测试与分析

为进一步优化鞍钢 170 0中薄板坯连铸连轧 ( ASP)轧制工艺 ,提高其生产能力 ,改善产品质量 ,对 R1粗轧机进行了各种工况下轧制扭矩、扭振、振动及其他力、电参数综合测试。结果表明 :R1轧机主传动系统在板坯咬钢和含钢升速时会产生扭振 ,最大扭矩达到 1981k N· m,扭矩放大系数 TAF小于 2 .0 0 ,扭振频率 16.5～ 17.5 Hz,最大轧制力 2 2 80 0 k N,与 R1轧机机电设计能力相比尚有潜力。本次测试为实现优质、低消耗、低成本生产和设备安全、经济运行提供可靠的依据     

轧机传动系统在急剧振动时扭矩值的测量和分析

对不同类型轧机传动系统的扭振进行了在线测量,并对测量数据采用快速富氏分析法进行频谱分析。介绍了扭矩测量的先进方法及其原理;列出了几套轧机的扭振特性;分析了引起扭振的因素及防止方法。这对认识轧制过程的扭振现象,正确操作和避免事故,具有指导意义     

粗轧机主传动扭振分析

分析了粗轧机主传动扭振模型及动态特性计算方法.在分析过程中考虑到轧辊与主传动动力侧之间的周向间隙对扭振响应幅度的影响,根据咬钢过程中间隙的启闭规律,基于龙格-库塔方法实现了扭振响应的数值仿真.对宝钢2050轧机R2主传动各工况进行了数值仿真,结果表明:当咬钢瞬间板坯速度大于轧辊圆周线速度水平分量时,轧辊与系统动力侧之间的接轴间隙打开,相对于间隙常闭工况,上下分支主轴的扭矩放大系数都有所增大,增幅达4%～20%.     

轧机动系统在急剧振动时扭矩值的测量和分析

对不同类型同传动系统的扭振进行了在外测量,并对测量数据采用快速富氏分析法进行频谱分析。介绍了扭矩珠先进方法及其原理;列出了几套轧机的扭振特性;分析了引起扭振的因素及防止方法,这对认识轧制过程的扭振现象,正确操作和避免事故,具有指导意义。     

1150初轧机轴系扭振实测分析

国内几台1150初轧机的万向连接轴都先后出现过崩裂破坏事故,引起了生产、科研、设计部门以及电机制造厂的普遍重视。我组根据多次在初轧机上用电阻应变仪及光线示波器对轧制力及传动扭矩的实测研究,发现初轧机轴系的扭转振动非常明显,而上述破坏事故与咬钢时的冲击扭振有关。本文是在包钢1150初轧机上进行实测后的部份专题总结。主要内容是把振动理论与初轧机的生产实践结合起来,论述初轧机咬钢及甩钢过程的扭矩放大系数,从而得出几点有益的启示。     

六辊冷连轧机板形前馈控制方法的研究

 本文针对六辊冷连轧机,研究了采用工作辊弯辊的整体补偿板形前馈控制方法和采用工作辊与中间辊弯辊相结合的最优综合补偿板形前馈控制方法。实际控制效果表明,整体补偿板形前馈控制方法只能抑制由于轧制力波动产生的二次板形,而对四次板形几乎不产生影响;最优综合补偿板形前馈控制方法对轧制力波动造成的二次和四次板形均具有很强的控制能力。     

可逆冷轧机前馈最佳补偿的仿真研究

一、前言 带材轧机中的厚度自动控制(简称AGC)系统,除普遍采用GM—AGC、X射线测厚AGC、张力AGC等反馈控制系统外,还逐渐采用前馈AGC。这是由于反馈控制存在固有的控制滞后,动态精度较差。前馈具有预控作用。它通过提前检测扰动,并使压下提前动作,当扰动到达辊缝时,其影响已全部或部分被消除,因此有较好的动态特性。特别是随着DDC系统的采用,带材轧机     

Vibration Control of Wind-Excited Tall Buildings Using Sliding Mode Fuzzy Control

A sliding mode fuzzy control (SMFC) is proposed to design a controller for the third-generation benchmark problem on wind-excited buildings. A distinctive feature in vibration control of large civil infrastructure is the existence of large disturbances, such as wind, earthquake, and sea wave forces. Those disturbances govern the behavior of the structure; however, they cannot be precisely measured, especially for the case of wind excitations. Since the structural accelerations are measured only at a limited number of locations without the measurement of the wind forces, the structure of the conventional control may have the feedback loop only. The general structure of the SMFC, proposed herein, is composed of a compensation part and a convergent part. The compensation part prevents the system from diverging, and the convergent part directs the system to the sliding surface. The compensation part uses not only the structural response measurement but also the disturbance measurement, so the SMFC has a feedback loop and a feedforward loop. To realize the virtual feedforward loop for the wind-induced vibration control, a disturbance estimation filter is introduced. The structure of the filter is constructed based on an autoregressive model for the stochastic wind force. This filter estimates the wind force at each time instance based on the measured structural responses and the stochastic information of the wind force. For verification of the proposed algorithm, numerical simulation is carried out on the benchmark problem for wind-excited buildings. The results indicate that the present control algorithm is efficient for reducing the wind-induced vibration.     

轧机主传动系统扭振建模及分析

该数学模型考虑了减速器齿轮的啮合刚度对系统的影响,并通过计算得到系统的用保守系统拉格朗日方程建立了某铝带热轧机主传动系统的扭转振动数学模型固有频率和主振型及其对转动惯量和扭转刚度的灵敏度;用模态叠加法计算了系统在冲击载荷作用下的动力学响应,得出了各轴段扭矩放大系数的仿真结果,以判定扭振发生时主传动系统的最大动力载荷。计算发现该轧机主传动系统扭振固有频率分布并不十分理想,有必要进一步优化。分析结果对扭振问题的识别和解决具有指导作用。     

Model and Control of Flexible Multibody Satellite

In order to estimate total disturbances including parametric uncertainties, unmodeled dynamics, and external disturbances, and achieve the dynamic feedback compensation of the estimated total disturbances, we design a double closed loop attitude active disturbance rejection controller (ADRC). By taking flexible vibrations of solar panels and a flexible antenna as an external disturbance, and using only the estimated transformation matrix of control input, a simplified dynamic model has been used to replace the accurate dynamic model of a rigid body in a flexible multibody satellite dynamics model. Simulation results indicate that the attitude ADRC designed still has the original dynamic response when large external disturbance acts on the system. Therefore, we come to the conclusion that the ADRC designed can be used to solve the problem of control systems with uncertainties in the process of modeling different flexible multibody systems.     

Robust Backstepping Sliding Mode Attitude Tracking and Vibration Damping of Flexible Spacecraft with Actuator Dynamics

This paper presents a dual-stage control system design method for the attitude tracking control and vibration stabilization of a spacecraft with flexible appendages embedded with piezoceramics as sensor and actuator. In this design approach, attitude control system and vibration suppression were designed separately using a lower order model. Based on the sliding mode control (SMC) and backstepping technique, a new attitude controller in the form of the input voltage of the reaction wheel is derived to control the attitude motion of a spacecraft, in which the reaction wheel dynamics is also considered from the real applications point of view. Here the sliding mode technique is used to achieve an asymptotic convergence of the attitude and angular velocity tracking errors in the presence of parameter variation and disturbance by providing a virtual torque input at the rigid body while the backstepping technique is used to regulate the input voltage of the actuator to provide the required torque. The asymptotic stability is shown using a Lyapunov analysis. Furthermore, an adaptive version of the proposed attitude control law is also designed for adapting the unknown upper bounds of the lumped disturbance so that the limitation of knowing the bound of the disturbance in advance is released. For actively suppressing the induced vibration, strain rate feedback control methods are presented by using piezoelectric materials as additional sensors and actuators bonded on the surface of the flexible appendages. The performances of the hybrid control schemes are assessed in terms of attitude tracking and level of vibration reduction in comparison to the proportional-derivative and conventional SMC. Both analytical and numerical results are presented to show the theoretical and practical merit of this hybrid approach.     

轧机扭振新微分算子法研究

1982年春,在应用微分算子法和模态分析法等计算中板轧机主传动系统扭转振动固有频率和扭振扭矩放大系数时,发现前苏联学者斯·恩·科茹夫尼科夫《带弹性键环机械动力学》中,应用微分算子法求解系统扭振动态响应有错误,计算结果与模态分析法、拉氏变换法等不同。在本论文中,提出微分算子法解常系数非齐次线性微分方程组的一种新解法并结合实例进行具体计算。虽然微分算子法较复杂,但它的结果较为清晰,能对各参数的影响进行分析,由此可研究采取相应的对策,较其它的方法有独特的优点。     

冷带轧机速度控制系统负载扰动观测器的设计及应用

冷带轧机直流驱动电机与轧辊间的距离较长、连接轴刚度有限,因此在带材高速轧制时,常规转速、电流双闭环控制易产生振荡和断带现象。为了克服该缺陷,本文设计了负载扰动观测器及带前馈补偿的直流调速控制系统。仿真结果表明所设计的系统有效地改善了系统的动、静态性能,并巳在实际中得到了较好的应用。     

Carrousel卷取机传动系统扭振分析

在研究和分析Carrousel卷取机传动系统的基础上,采用集中质量参数模型的方法建立Carrousel卷取机传动系统的力学模型。并结合拉格朗日方程建立起了一个通用的数学模型,用以分析Carrousel卷取机传动系统的扭转振动特性。在此力学模型和数学模型的基础上,对系统的固有模态,扭矩放大倍数,不同的加载方式下系统的动态响应以及系统的灵敏度进行了研究。通过与有限元方法的计算结果进行比较可知,采用该力学模型和数学模型来研究Carrousel卷取机的扭振特性是可行的。     

矿热炉电极调节系统的双闭环自抗扰控制

对矿热炉电极系统提出了一种自抗扰控制策略的控制方法。设计了一种不依赖于对象模型的电极自抗扰控制器,并对其参数进行了整定,自抗扰控制器的扩张状态观测器可以实时观测系统状态和扩张状态,从而实现全状态反馈及系统不确定性和外扰的补偿控制。该系统与传统的单闭环恒流控制系统比较,增加了电极位置环。仿真实验表明,该控制系统不仅具有较强的鲁棒性,对内外干扰具有较强的抑制能力,更具有较优的动态性能。