可变磁路式永磁悬浮平台的起浮控制方法

磁悬浮技术应用于超洁净传送,可有效减少粉尘污染. 可变磁路式永磁悬浮平台具有低功耗、抗吸附的特性,可避免电磁悬浮传送平台温升大和混合磁悬浮平台安全性差的弊端. 为解决永磁悬浮平台起浮过程易发散的问题,提出并验证分散控制、集中控制和积分分离法3种起浮控制方法. 首先,分析可变磁路式永磁悬浮平台的磁力控制原理,建立系统动力学模型,并采用分散控制实现悬浮平台起浮;然后,针对起浮后平台倾斜的问题,提出了三自由度集中控制方法,其中平台的垂向控制为PD （proportional differential）,侧倾与俯仰方向为PID（proportional integral differential ）;最后,应用积分分离法进行分段控制,以实现垂向的精确定位. 研究结果表明:集中控制方法实现了平台倾斜角的自纠偏,可有效解决分散控制下各磁极磁力特性差异引起的平台倾斜问题,调节时间为0.5 s;垂向采用积分分离方法后,平台垂向的稳态误差由0.23 mm可减小为0,调节时间为3.0 s. 

Floating Control Method for Permanent Magnetic Levitation Platform with Variable Flux Path

Application of the magnetic levitation technology in ultra-clean transmission can effectively reduce dust pollution. The permanent magnetic levitation platform with a variable flux path has the characteristics of low-power consumption and anti-adsorption, which can avoid the large temperature rise in electromagnetic levitation systems and poor safety of hybrid electromagnetic levitation systems. To avoid the instability in the floating, three floating control methods are presented and validated, which are decentralized control, centralized control and integral separation. At first, the magnetic-force control mechanism of the platform is analyzed to build its dynamic model, and the decentralized control strategy is adopted to realize the floating. Furthermore, a 3-DOF centralized control strategy is proposed to prevent platform tilt, in which the vertical controller is PD (proportional differential) and the rolling and pitching are controlled by PID (proportional integral differential). Finally, the integral separation method is used for subsection control to realize the accurate vertical positioning. The results indicate that the centralized control method realizes the self-correction of the platform tilt angle with the adjustment time of 0.5 s, which solves the platform tilt caused by the magnetic characteristics difference of each pole in the decentralized control. Moreover, when using the integral separation method, the vertical steady-state error of the platform can be reduced from 0.23 mm to 0 with the adjustment time of 3.0 s.