Application of stepper motor in packaging machinery

This paper discusses the working principle and use characteristics of stepper motor, introduces several application examples of stepper motor in packaging machinery, and points out that stepper motor has broad application prospects in packaging machinery.

After nearly 20 years of development, China's packaging machinery has made great progress, but compared with foreign countries, there is still a big gap, where is the gap? We believe that it is mainly in terms of control. In view of this, Yang Fuji of Wenzhou University and Wu Longqi of Henan University of Science and Technology have written a series of articles on the research content they are engaged in, hoping to inspire the relevant industry insiders.

First, the working principle of stepper motor

A stepper motor is an open-loop control element that converts a given electrical pulse signal into an angular displacement or line displacement.

Given an electrical pulse signal, the stepper motor rotor is rotated through the corresponding angle, which is called the step angle of the stepper motor. At present, the step angle of commonly used stepping motors is mostly 1.8 degrees (commonly known as one step) or 0.9 degrees (commonly known as half step). For a progressive motor with a step angle of 0.9 degrees, when we give the stepper motor an electrical pulse signal, the stepper motor turns over 0.9 degrees; for two pulse signals, the stepper motor turns over 1.8 degrees. By analogy, the stepping motor can be continuously operated given the pulse signal continuously. Due to the linear relationship between the electric pulse signal and the rotation angle of the stepping motor, the stepping motor has been widely used in speed control and position control.

The use of stepper motor requires at least three aspects. First, the electric pulse signal generator repeats the electric pulse signal for the stepper motor according to the given setting. At present, most of this signal is controlled by a programmable controller or a single chip microcomputer. The second is the driver (signal amplifier), which not only amplifies the electric pulse signal, but also drives the stepping motor to rotate, and can also improve the performance of the stepping motor. In fact, it plays a role in the stepping motor system. An important role, generally a stepper motor can have a variety of drivers according to different working conditions; the third is a stepper motor, which has a variety of control principles and models, now commonly used reactive, inductive, hybrid, etc. .

The speed control of the stepper motor is achieved by the input pulse frequency. When the frequency of the pulse decreases, the speed of the stepper motor decreases; as the frequency increases, the speed increases. It is also possible to increase the speed or positional accuracy of the stepper motor by changing the frequency.

The position control of the stepper motor is controlled by the given number of pulses. Given a pulse, a step angle is turned. When the stop position is determined, the number of pulses required for the stepper motor is determined. In the packaging machine control, the number of given pulses is also related to the parameters of the mechanism, such as the diameter of the screw.

In packaging machinery, in many cases it is necessary to control the operating speed and operating position of the actuator, which was previously done by mechanical or Other means, and the mechanism is complicated and the adjustment is not easy. When the stepping motor is used, the packaging mechanical structure can be simplified, the adjustment is convenient, the reliability is increased, and the thickness is greatly improved.

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