Development of an Instrument Control System & Closed Loop Motion Controls for Stepper Motors

Abstract

Mount Abu Faint Object Spectrometer and Camera - Pathfinder (MFOSC-P) is a proposed instrument for PRL 1.2m telescope at Gurushikhar, Mount Abu. This project address one of its blocks which is a micro controller based electronic instrument control system (ECS). ECS card is equipped with feedback components. ECS is envisioned to provide an automation to MFOSC-P. In this thesis, the main focus is on motion control of stepper motor. For that closed and open loop motion control algorithms are developed and implemented. The algorithms are being developed by taking the outputs from various feedback components like limit switches and optical encoders in to account. The end use of such system is to fully automate the motion and control aspects of linear as well as rotational motion of bipolar stepper motor. In this project, software is developed to control stepper motor which is attached with filter wheel. Filter wheel contains different types of filters. These stepper-motor-driven filter wheels are designed for use in a host of automated applications including color CCD photography, microscopy and photometry. To control these motors various commands are sent from command line interface that is from control PC. After executing the motion control commands, controller will send data back to the command line interface. Depending upon the feedback, next command will be sent from control PC. The result show that closed loop motion control can give guaranteed higher accuracy compared to open loop motion control system.