What is the difference between full-step and microstepping in a stepper motor?

Stepper motors are a type of motor commonly used in industrial and commercial applications due to their high accuracy, precise control, and easy integration with digital control systems. One of the essential parameters that affect the performance of a stepper motor is the step size, which determines the angular displacement of the rotor for each input pulse. There are two common methods of stepping in a stepper motor: full-step and microstepping. In this article, we will discuss the difference between these two methods and their respective advantages and disadvantages.

Full-Step Stepping:

Full-step stepping is the simplest and most commonly used method of stepping in a stepper motor. In full-step stepping, the rotor is moved by a fixed angle equal to the step angle of the motor for each input pulse. The step angle is determined by the number of rotor teeth and the number of stator windings in the motor. For example, a stepper motor with 200 steps per revolution has a step angle of 1.8 degrees (360/200). The input pulse to the motor determines the direction of rotation and the number of steps taken.

Full-step stepping provides high torque and is suitable for applications that require high speed and low resolution. However, it suffers from several disadvantages. First, the high torque causes vibration and noise, which can affect the motor's accuracy and lifespan. Second, the fixed step size can lead to resonance and resonance-related issues, which can reduce the motor's performance.

Microstepping:

Microstepping is an advanced method of stepping in a stepper motor that offers higher resolution and smoother motion compared to full-step stepping. In microstepping, the rotor is moved by a fraction of the step angle for each input pulse. The fraction is determined by the current amplitude and phase shift in the stator windings. For example, in a typical microstepping mode, the rotor is moved by 1/16th of a full step angle for each input pulse.

Microstepping provides several advantages over full-step stepping. First, it offers higher resolution and smoother motion, resulting in improved accuracy and reduced vibration and noise. Second, it reduces the risk of resonance-related issues due to the fractional step size. Third, it allows for more precise control over the motor's speed and torque, making it suitable for applications that require high precision.

However, microstepping also suffers from a few disadvantages. First, it may result in reduced torque due to the fractional step size, making it unsuitable for high-torque applications. Second, it requires more complex control electronics and algorithms to generate the current waveform for microstepping, increasing the cost and complexity of the system.

In conclusion, the difference between full-step and microstepping in a stepper motor lies in the step size and the method of movement. Full-step stepping provides high torque but suffers from vibration and resonance-related issues, while microstepping offers higher resolution and smoother motion but may result in reduced torque and increased complexity. The selection of the stepping method depends on the specific application requirements, and the motor's performance characteristics should be carefully considered before making a decision.