Design of a Variable Reference Current Controller for Micro-stepping Motor Based on Vibration and Missing Step Characteristic Data

The use of pan-tilt-zoom cameras is continuously increasing for surveillance applications because they can monitor a large area of the environment at a high resolution. The most crucial requirements are low vibration, ensuring the excellent quality of the video at a high zoom ratio, low power consumption, synchronous motion, and small size. This paper proposes a novel micro-stepping controller called a variable reference current (VRC) controller with a motion and current generator based on the experimental data, such as vibration and missing step characteristics. It creates a third order S-shaped motion profile and generates a reference current profile. The experimental results show that VRC controller reduces vibration and consumes low current compared with the conventional fixed current controller. Moreover, the proposed VRC controller, implemented in a single FPGA, enables driving the multiple step motors synchronously without missing steps, using prior experimental data on vibration and margin area characteristics to prevent missing steps.