| In fiber spectroscopic telescopes,optical fiber positioning units are used to position thousands of fibers on the focal plane quickly and precisely.Stepper motors with high position accuracy are used in the existing units.However,the stepper motors suffer from some inherent deficiencies,such as serious heating effect and low efficiency.In this work,the universally adopted subdivision driving technology for stepper motors is transplanted to brushless DC motors,which not only overcomes the disadvantages mentioned above but also inherits the advantages of stepper motors in the mean time.Thus,this research mainly focuses on developing a novel subdivision positioning technology for brushless DC motor.In this paper,we firstly analyzed the principle of subdivision driving for stepper motor and studied the characterisitics of brushless DC motor,which aims to develop a decent method of suudivision for brushless DC motor.Then,four sets of driving plans are designed to research the technology,including online platform driving,Three Harmonic driving without sensor,chip driving and module driving.The hardwaves for those driving schemes include drving module,power module,MCU control module and the input&display module.What's more,the power consumption and heating effect of the driving board are observably decreased by the optimal circuit layout and the chip selection.Lastly,a set of multiple driving positing experiments were designed to experimently verify the subdivision driving technique for brushless DC motor.The experimental results show that the proposed two-subdivision and four-subdivision technique for brushless DC motor achieve higher positioning accuracy than without the technique.Center shaft and eccentric shaft show high repeat positioning accuracy and excellent operation status in the subdivision positioning experiments of 10mm unit.In the experiments,the communication of the master node and sub-node were accomplished using the ZigBee protocol. |
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