数控机床用新型磁悬浮直驱主轴及其协调容错控制

The direct drive spindle is the core component of the CNC Machine. However, the conventional direct drive spindle possesses the drawbacks such as complicated structure, high cost, difficulty in further improving the speed and power, etc. To effectively eliminate the aforementioned disadvantages, a novel magnetic levitation direct drive spindle is presented in this project, and the coordinated fault-tolerant control strategies are also researched. The magnetic levitation direct drive spindle, which consists of a 2 degree of freedom (DOF) bearingless permanent magnet motor and a 3 DOF magnetic bearing, incorporates the merits of high reliability, high speed, high efficiency, low cost, low power consumption and so on. The aim of this project is to develop a novel magnetic levitation direct drive spindle with the reasonable topological structure. Thus, the general method of theoretical analysis, electromagnetic parameters calculation, and mathematical modeling will be established. Secondly, the fault-tolerant control strategies for the magnetic levitation direct drive spindle will be investigated under different fault conditions, and the system reliability will be improved accordingly. Thirdly, by analyzing the nonlinear coupling characteristics between the electromagnetic torque and suspension forces, the coordinated control theory based on the support vector machine inverse will be proposed. Finally, the dSPACE-based digital control system experiment platform will be built, and the corresponding experimental researches will be developed. Meanwhile, the basic problems of science can be clarified, and the general rules of the coordinated fault-tolerant control for the magnetic levitation direct drive spindle system can be summarized. The project involves several disciplines such as mechanical engineering, electrical engineering, and control engineering. The successful completion of the project will lay a foundation for the development of domestic intellectual properties of the direct drive spindle system for CNC Machines, and it can also be applied into other magnetic levitation drive fields with high reliability and high performance.

直驱主轴是数控机床的核心部件，项目针对传统直驱主轴存在结构复杂、成本高、转速和功率难以进一步提高等缺点，提出一种新型磁悬浮直驱主轴，并开展其协调容错控制研究。该磁悬浮直驱主轴由二自由度无轴承永磁电机和三自由度磁轴承融合而成，具有高可靠性、高速、高效、低成本、低功耗等优点。本项目旨在设计出结构新颖合理的磁悬浮直驱主轴拓扑结构；建立其理论分析、电磁参数计算、数学建模的一般方法；研究故障状况下容错控制策略，提高系统可靠性；剖析电磁转矩、悬浮力之间非线性耦合特性，提出基于支持向量机逆的协调控制理论；构建基于dSPACE的数字化控制系统实验平台，进行实验研究；提炼基础科学问题，探索磁悬浮驱动系统协调容错控制的一般性规律。项目属机械工程、电气工程、控制工程等交叉学科的应用基础领域，其研究将为我国研制出具有自主知识产权的数控机床直驱主轴系统奠定基础，还可以推广到高可靠性、高性能磁悬浮驱动的其它应用领域。

项目以磁悬浮直驱主轴高可靠性、高效率、高速高精、低成本运行为目标，在磁悬浮直驱主轴数学模型、有限元分析、非线性磁链建模、容错控制、非线性解耦协调控制和数字控制实现等方面开展了工作，取得了多项创新性成果。研究期限内，发表论文42篇，其中SCI检索18篇(含2篇一区，2篇二区)，EI检索18篇；申请国家发明专利28项，其中授权20项；相关成果获教育部发明二等奖1项、获江苏省科学技术二等奖和三等奖各1项。主要研究内容与创新成果概略如下：.1.综述了无轴承永磁电机的关键技术，包括对无轴承永磁电机的几种典型结构、数学模型以及无轴承永磁电机的控制技术进行了详细分析。.2.推导得出了磁悬浮直驱主轴转子所受麦克斯韦力的表达式，并对气隙磁路进行分析与简化。根据麦克斯韦力与气隙磁密的关系，建立了计及转子偏心时的径向悬浮力。对表贴式与内置式无轴承永磁电机进行对比分析，研究了不同转子结构对无轴承永磁电机电磁特性的影响。对用于磁悬浮直驱主轴悬浮支承的三自由度混合磁轴承进行了优化设计，采用等效磁路法对磁路进行了推算，建立了悬浮力数学模型。.3.提出了一种磁悬浮直驱主轴用新型结构的单绕组无轴承电机，该电机采用一套绕组实现转子的悬浮和旋转，基于二基波法研究了该电机悬浮力的数学模型。提出了一种单绕组无轴承电机的驱动控制方法，该控制方法将传统双绕组无轴承电机的两套绕组控制二合为一，不仅简化了控制系统，还有效提高了转矩和悬浮力。.4.提出了一种具有容错齿结构、采用Halbach永磁铁阵列的单绕组无轴承永磁电机。为了实现磁悬浮直驱主轴径向悬浮系统在正常运行以及带故障运行时的解耦控制，提供一种基于双支持向量机逆模型的容错解耦控制方法。.5.针对磁悬浮直驱主轴用无轴承电机磁链、转子位置角、径向偏心位移、绕组电流之间的强烈非线性特性关系，提出了基于自适应权重最小二乘支持向量机的无轴承电机磁链非线性建模的方法。.6.针对磁悬浮直驱主轴多变量、非线性、强耦合的特点，将逆系统方法与支持向量机相结合，提出了基于支持向量机逆理论的磁悬浮直驱主轴协调解耦控制方法。在此基础上，设计了内模控制器提高整个系统的控制性能。.7.构建了磁悬浮直驱主轴数字驱动控制系统，研制了系统的软硬件驱动电路，开发了控制系统的软件程序，为研发出高效率、高可靠性的磁悬浮直驱主轴驱动系统提供了实验基础，并且在该数字控制实验平台上，进行了详细的实验研究。