| Linear stepping electric motor is a widely used digital implementing unit. The research to linear stepping motor has significant meaning.This article introduces the status quo of linear stepping electric motor and research content of this topic, then discusses the development of linear stepping motor drive unit and general situation of the researched sample unit, furthermore supply the detailed introduction to DSP controller.TMS320F240 chips adopted in this article is produced in TI. At its beginning this article describes the structure of DSP, then its characteristics which includes the arithmetic operation, speed and pattern. The designing plan and explanation of software and hardware are also introduced.With the development of modern drive technology, the precision of linear stepping electric motor is constantly improving which may satisfy majority of the users, thus it is very occasionally to implement the R&D to close-loop control. However , with the development and request of high precision servo control, open-loop control becomes more and more incapable to fulfill the precision demand of units. Taking the sample unit as an example, its positioning accuracy reachesto 0.03mm which can not be satisfied by the common open-loop control.Thus close-loop has to be introduced. As the running characteristics of linear stepping electric motor, its velocity variation decisively relies upon the factors of frequency and amplitude. For the sample unit is a two-phased mixed linear stepping motor, thus makes its speed frequency quadruple that of single-phased voltage. This article adopts double-close-loop for speed tuning, i.e. adjusting input voltage by amplitude tuning, while adjusting source voltage by frequency tuning. All this has achieved satisfied effect. This article describes the MATLAB/SIMULINK software for its steady and transient state simulation. After comparison to the experimental result, the reliability and feasibilityhas be proved for arithmetic method of closed-loop system. |
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