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.
洛伦兹电动机广泛应用于超精密制造装备中。为提高洛伦兹电动机的推力输出和快速响应性能,降低发热功率,提出了一种综合评价超精密工作台驱动电机性能的优化指标。基于该优化指标,采用COMSOL Mu l-tiphysics和M atlab联合仿真方法,对一种Halbach磁钢阵列构型的洛伦兹电动机进行了尺寸参数优化设计。样机实验证明,优化后的洛伦兹电动机推力可以达到26.3 N/A,同时保证电气时间常数小于1 m s。
