6-DoF Magnetically Levitated Rotary Table With Dynamic Numerical Force and Torque Regulator
Fengqiu Xu, Ruotong Peng, Kaiyang Zhang, Xianze Xu
Abstract
Multiaxis motion control over a large travel range is still difficult for magnetic levitation positioning systems because the accuracy of the magnetic force model deteriorates when both translation and rotation of the moving part take place. To overcome this issue, this article studies a dynamic force- and torque-regulating method based on the numerical wrench model and validates it with a 6-degree-of-freedom magnetically levitated (maglev) rotary table. In each sampling cycle, the current-wrench transformation matrix is determined by the numerical wrench model, and then it is employed to decide the exciting currents for each coil phase by solving the overdetermined equation. A field programmable gate array is used as the processor to meet the real-time requirement of the control system by taking advantage of the fine-grained parallelism in the numerical wrench model. A high-level synthesis tool, general intellectual property core, a very-high-speed integrated circuit hardware description language component, and a MicroBlaze processor are employed simultaneously to develop the controller. By utilizing the numerical regulator, the maglev rotary table realizes stable multiaxis motions. Comparative experiments with the existing analytical method illustrate that the numerical wrench model improves the static decoupling effect, decreases the positioning fluctuations, and enlarges the travel range.