二阶动态滑模控制在磁悬浮控制系统中的应用

磁悬浮是典型的非线性、不稳定系统.为了实现其控制,本文采用了一种结合二阶滑模和动态滑模两种设计思想的二阶动态滑模控制器的设计方法,首先推导了磁悬浮系统的线性化状态空间模型;然后针对被控对象设计了二阶动态滑模控制器;最后与普通滑模控制器进行对比仿真试验.仿真结果表明,所设计的二阶动态滑模控制器在使小球快速稳定到达平衡点的同时,大大削弱了普通滑模控制器中存在的严重抖振现象.     

新型永磁同步无轴承电机的设计

对一种新型薄片式永磁同步无轴承电机的设计进行了分析。从无轴承电机和普通永磁电机的基本原理出发，通过对各种转子结构的比较，研究它们的磁场分布，提出了一套优化的转子结构。与传统的电机相比，内转子薄片式永磁同步无轴承电机的结构比较特殊，它的运行原理、分析和设计与普通无轴承电机有着较大的不同且应用前景广阔。着重阐述了内转子薄片式永磁同步无轴承电机的工作原理和控制方法。     

An ionization chamber with magnetic levitated electrodes

A new type of ionization chamber which has magnetically levitated electrodes has been developed. The electrodes are supplied voltages for the repelling of ions by a battery which is also levitated with the electrodes. The characteristics of this ionization chamber are investigated in this paper.     

VERTICAL NONCONTACT POSITIONING H∞ ROBUST CONTROL FOR MAGNETICALLY LEVITATED SURFACE MOTOR

To fulfill the stringent requirement, super-precision positioning and ultra cleanness, a surface motor with the integrated chip fabrication equipment is constructed by using permanent magnets and electromagnet coils as primary actuating components. It consists of stator and mover, and the mover is isolated from the stator by the magnetic beating. The magnetic bearing in the stator is composed of eight air core electromagnet coils, the propulsion in the stator is composed of iron core and electromagnetic coils, and the mover is composed of NdFeB permanent magnets and levitated stage. Based on Lorentz law, some parameters, including permanent magnets dimensions, currents and levitation height, which may affect the stability, are analyzed and optimized. To improve the positioning accuracy in the vertical direction of the magnetic levitation surface motor, a robust controller is proposed using H∞ mixed sensitivity control theory. The simulation results show that by choosing appropriate weight functions, the controller can ensure the robustness of the closed loop system under the presence of uncertainties, and the H∞ robust controller is excellent for reducing steady error and increasing response speed.     

反磁悬浮涡流旋转微陀螺的定子研究

介绍的一种反磁悬浮涡流旋转微陀螺的定子研究.利用现有实验设备,通过多次实验摸索,找到了一条实现反磁悬浮涡流旋转微陀螺下定子合理的工艺路径,并进行了测试,测试显示定子结构完整正常.     

Statics of levitated vehicle model with hybrid magnets

By studying the special characteristics of permanent and electronic magnets, a levitated vehicle model with hybrid magnets is established. The mathematical model of the vehicle is built based on its dynamics equation by studying its machine structure and working principle. Based on the model, the basic characteristics and the effect between the excluding forces from permanent magnets in three different spatial directions are analyzed, statics characteristics of the interference forces in three different spatial directions are studied, and self-adjusting equilibrium characteristics and stabilization are analyzed. Based on the structure above, the vehicle can levitate steadily by control system adjustment.     

工艺参数对电渣感应连续定向凝固组织稳定性的影响

电渣感应连续定向凝固组织稳定性主要取决于结晶器壁内温度与金属熔体的温度梯度，工艺参数的相互配合是获得理想凝固组织的关键；固液界面形状可用其形状因子Ｘ＝１０＾－４ψＢＴＸＣ／（ａＶ）来表示，利用Ｘ可实现对凝固过程中固液界面形状进行监测 。     

Current-bounded commutation of a long-stroke magnetically levitated stage with moving coils

Magnetically levitated stages(MLS) have potentials to obtain good motion performances in high vacuum environment. Yet the electromagnetic forces/torques corresponding to six degrees of freedom(DOF) motions have coupling relationship with each current of coil array, and this coupling is still associated with the relative positions between the mover and the stator of the stage. So it is quite difficult to control the 6-DOF motions of the stage. By reasonable commutation of coil array, this complicated coupling relationship can be decoupled. The analytical force/torque-decomposing model of the stage is established first. Then the initial currents of coil array are commutated based on the pseudo inverse of the analytical force/torque-decomposing model matrix. And then the coil array currents are commutated again with different current bounds given to the initial currents as well as in the sense of minimum 2-norm of currents vector. Using the long stroke magnetically levitated stage with moving coils under investigation as examples, the currents of coil array are commutated with different current bounds adopting the proposed commutation method, the determination of current bound and the current bounds’ influences on the heat-losses in coil array are analyzed, and the effectiveness of implementation algorithm of proposed commutation method is discussed. Simulation, analysis and discussion results indicate that the currents of coil array within the given current bound can be solved analytically by proposed commutation method, and the implementation algorithm does not need any searching or iteration. By the current-bounded commutation method proposed, the amplitude of coil array currents can be limited within an appropriate current bound(This is very beneficial to the improvement of the reliability and motion performance of the stage), as well as these currents can also generate the desired forces and torques.     

永磁电磁混合磁浮列车的永磁磁场仿真

磁浮列车的结构参数、磁场分布关系到磁体斥力、效率和可靠性,因此有必要对磁体的整体结构分布、磁极数、磁体厚度、气隙等参数及其构成的磁场进行深入研究。基于磁路设计的基本原理,本文采用MATLAB、ANSYS软件,探讨永磁悬浮电磁导向磁浮列车的磁场分布及其大小的影响因素,分别研究永磁场的二维平面分布和三维立体分布,通过磁场分析、建模,对其磁场进行数值计算。结果表明,采用本文数值仿真方法计算的气隙内磁感应强度及其磁力线分布,为最终确定磁浮列车的稳定悬浮间隙大小提供重要数据。     

磁悬浮运动平台的非线性变结构控制

磁悬浮运动平台具有非接触、无摩擦和无磨损等优点,适合做精密测量和定位设备.针对磁悬浮运动平台动力学模型的强耦合、非线性特点,利用非线性系统的反馈精确线性化方法,实现了运动平台悬浮位置和水平位置的非交互式控制,同时根据垂直方向和水平方向的不同特点分别设计了变结构控制器.仿真结果表明,该方法很好的实现了对悬浮驱动和水平驱动的解耦控制,且控制器具有较强的鲁棒性.