共查询到20条相似文献,搜索用时 109 毫秒
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针对磁轴承转子系统在运行时因转子质量不平衡导致的同频扰动问题,提出了将反推控制算法和扰动观测器相结合形成一个复合控制器的控制策略.对磁轴承转子系统中的同频信号进行观测,并在输入信号中对同频扰动信号进行抑制.建立了转子动力学模型,设计了反推控制器和扰动观测器,通过MATLAB仿真,结果表明:该复合控制器比反推控制器对扰动... 相似文献
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针对以往磁轴承转子系统的振动抑制能力不足的问题,对新型同位电磁阻尼和单自由度磁轴承转子系统进行了研究,提出了一种同位电磁阻尼并应用到抑制磁悬浮转子的振动中。基于以往阻尼力模型重新推导了同位阻尼力数学模型,考虑了线圈电流变化对阻尼力模型的影响,并利用磁矢位计算使阻尼力模型更加精准,分析了同位阻尼力在转子上的分布情况及与电流和位移的关系。将同位阻尼与单自由度磁轴承相结合,建立了新型同位阻尼磁轴承模型,利用该磁轴承模型对同位阻尼抑制转子振动能力进行了分析。仿真结果表明,新型磁轴承模型中的同位阻尼能够将转子最大振动位移偏差从无阻尼时的1.65×10-5m减小到2×10-6m,明显地减小了转子系统的位移偏差,能够达到增强磁轴承转子系统抑制振动能力的目的。 相似文献
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一种锥形定转子交直流磁轴承建模与耦合特性研究 总被引:1,自引:0,他引:1
为简化三自由度轴向-径向磁轴承结构,减小轴向长度和提高系统临界转速,设计了一种新型三自由度交直流轴向-径向混合磁轴承。该磁轴承定子采用两片式六极结构,分隔式锥形磁极与圆锥形转子均有30°锥角,磁场对圆锥形转子产生的磁吸力在轴向和径向方向上均有分量,实现了利用同一工作气隙同时控制圆锥形转子在轴向和径向3个自由度的悬浮。论文介绍了三自由度锥形定转子交直流混合磁轴承基本结构及悬浮力产生的工作原理,用等效磁路法对永磁和励磁混合磁轴承的磁路进行了分析,推导出了悬浮力数学模型。利用Matlab工具对磁轴承各变量之间的非线性关系和各自由度之间运动、磁路之间的耦合特性进行了计算和分析,并对各自由度之间的电磁耦合特性及各变量之间的非线性关系用ANSOFT软件进行了有限元分析验证。理论分析和仿真结果表明:该磁轴承各自由度在平衡位置附近时运动和磁路之间没有耦合,各变量之间具有良好的线性关系,对各自由度可采用分散独立的PID控制实现磁轴承的稳定悬浮。 相似文献
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主被动磁悬浮高速转子系统的自动平衡控制 总被引:1,自引:0,他引:1
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。 相似文献
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《机械工程学报(英文版)》2010,(5)
Conventional ball bearing reaction wheel used to control the attitude of spacecraft can't absorb the centrifugal force caused by imbalance of the wheel rotor,and there will be a torque spike at zero speed,which seriously influences the accuracy and stability of spacecraft attitude control.Compared with traditional ball-bearing wheel,noncontact and no lubrication are the remarkable features of the magnetic bearing reaction wheel,and which can solve the high precision problems of wheel.In general,two radial magnetic bearings are needed in magnetic bearing wheel,and the design results in a relatively large axial dimension and smaller momentum-to-mass ratios.In this paper,a new type of magnetic bearing reaction wheel(MBRW) is introduced for satellite attitude control,and a novel integrated radial hybrid magnetic bearing(RHMB) with permanent magnet bias is designed to reduce the mass and minimize the size of the MBRW,etc.The equivalent magnetic circuit model for the RHMB is presented and a solution is found.The stiffness model is also presented,including current stiffness,position negative stiffness,as well as tilting current stiffness,tilting angular position negative stiffness,force and moment equilibrium equations.The design parameters of the RHMB are given according to the requirement of the MBRW with angular momentum of 30 N ? m ? s when the rotation speed of rotor reaches to 5 kr/min.The nonlinearity of the RHMB is shown by using the characteristic curves of force-control current-position,current stiffness,position stiffness,moment-control current-angular displacement,tilting current stiffness and tilting angular position stiffness considering all the rotor position within the clearance space and the control current.The proposed research ensures the performance of the radial magnetic bearing with permanent magnet bias,and provides theory basis for design of the magnetic bearing wheel. 相似文献
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The design of a novel micro-magnetic bearing (MMB) for a 2-mm-diameter rotor is discussed. The bearing is supported by magnetic couplings generated by permanent magnets and is stabilized by a one-axis controller. The structure of the MMB is greatly simplified, not only in terms of machining and assembly of micro- and precision parts, but the number of mechanical parts is also reduced in comparison with previous designs of MMB. To increase the magnetic stiffness used to support the rotor in the passively controlled directions and to realize stable levitation using one-axis control, the dimensions of the mechanical parts that affect the magnetic stiffness are investigated using a finite element method. An MMB for a 2-mm-diameter rotor was constructed, such that the rotor could be levitated without mechanical contact and which rotated at 39,000 rpm. The static and dynamic characteristics of the MMB are evaluated, including magnetic stiffness, rotational accuracy and power consumption. 相似文献
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A passive permanent magnetic bearing rig prototype was designed and constructed. The suspension of the rotor was provided by two sets of radial permanent magnetic bearings operating in the repulsive mode. The axial support was provided by jewel bearings on both ends of the rotor. Preliminary testing led to successful operation of the bearing prototype to speeds of 5500 rpm using an air impeller. Radial and axial stiffnesses of the permanent magnetic bearings were experimentally measured and then compared to finite element results. The natural damping of the rotor was measured and a damping coefficient was calculated. 相似文献
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基于磁悬浮轴承高速电主轴的法向磨削力检测方法 总被引:1,自引:1,他引:1
利用磁悬浮轴承高速电主轴作为检测器件解决高速磨削法向磨削力实时在线测量困难的问题。通过对磁悬浮轴承高速电主轴转子的动力学分析,得到法向磨削力与电主轴转子位移的两阶导数和转子受到的电磁力的关系。转子的位移数据可由磁悬浮轴承电主轴中的位移传感器的输出得到。为了精确求取电磁力,气隙磁通密度采用图解法求出,消除线性化引入的系统误差;气隙宽度由遍历搜索法标定,消除系统加工装配误差对电磁力测量带来的影响;引入修正系数对由漏磁、磁滞和边缘效应带来的测量误差进行补偿,修正系数由三层神经网络动态实时求出。通过静态和动态试验对电磁力和动态磨削力的检测结果进行验证,试验结果证明基于磁悬浮轴承高速电主轴的法向磨削力检测方法的有效性和准确性。 相似文献
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电磁辅助支承恒压源与恒流源被动式减振之比较 总被引:1,自引:0,他引:1
对电磁辅助支承的两种被动减振类型(恒压型和恒流型)进行研究,建立了各自的数学模型,揭示了它们不同的减振机理:在恒压源被动减振控制情况下,电磁辅助支承中的电磁执行器不仅提供与转速无关的负的静态位移刚度,而且提供随转速变化的附加(正)刚度和(正)阻尼;而在恒流源被动减振控制下,线圈中的电流保持恒定, 电磁执行器仅提供不随转速变化的负的静态位移刚度。最后在一对称转子系统上进行了试验验证,并取得了较好的减振效果。 相似文献
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带弹性环保护轴承的动力学特性 总被引:1,自引:0,他引:1
提出在传统保护轴承外圈加弹性环来提高其在主动磁悬浮轴承(Active magnetic bearing,AMB)系统中的工作性能。为完善转子跌落仿真模型,得到AMB失效前转子准确的运动状态,理论推导得到AMB的支撑动刚度曲线,进而基于有限元分析方法得到转子在其支撑下的模态,并与试验结果进行对比,验证所得刚度曲线的正确性。在刚性转子理论基础上,建立转子在AMB系统中的动力学模型。基于Hertz接触理论,分别建立AMB失效后转子与保护轴承内圈之间的碰撞模型和保护轴承的实时动刚度模型。根据所建立的模型,对不同弹性环支撑刚度阻尼在不同初始转速下跌落后的动力学响应进行仿真计算,并与无弹性环状态下跌落结果进行对比。仿真分析结果表明,选用合适的弹性环有利于降低转子跌落后的振动幅值和碰撞力。分别在不同初始状态下进行跌落试验研究,试验结果与理论分析结果基本相符。 相似文献