Stepper Motor Control Technology Paper

As an actuator, stepper motors are one of the key products of mechatronics and are widely used in various automation control systems. I have compiled motor control technical papers for you, I hope you like them.

Motor control technology paper Part 1

Stepper motor control system

Abstract: As an actuator, stepper motors are one of the key products of mechatronics , widely used in various automation control systems. With the development of microelectronics and computer technology, the demand for stepper motors is increasing day by day, and they are used in various fields of the national economy.

Keywords: stepper motor; actuator; computer; development

1 Principle and characteristics of stepper motor

1.1 Current development of stepper motor< /p>

Stepper motors are open-loop control components that convert electrical pulse signals into angular displacement or linear displacement. When the stepper driver receives a pulse signal, it drives the stepper motor to rotate a fixed angle (called "step angle") in the set direction, and its rotation runs step by step at a fixed angle. The angular displacement can be controlled by controlling the number of pulses to achieve accurate positioning; at the same time, the speed and acceleration of the motor rotation can be controlled by controlling the pulse frequency to achieve speed regulation. Under non-overload conditions, the motor's speed and stopping position only depend on the frequency and number of pulses of the pulse signal, and are not affected by load changes. That is, when a pulse signal is added to the motor, the motor will rotate through a step angle. The existence of this linear relationship, coupled with the characteristics that the stepper motor only has periodic errors and no accumulated errors. It makes it very simple to use stepper motors to control speed, position and other control areas. The stepper motor can be used as a special motor for control. It is widely used in various open-loop controls by taking advantage of its characteristics of no accumulated error (accuracy of 100%).

1.2 Characteristics of stepper motors

1. When the stepper motor is working, each phase winding is not constantly energized, but is energized in turn according to a certain rule. 2. The angle the rotor rotates every time a pulse electrical signal is input is called the step angle. 3. The stepper motor can be controlled in angle according to specific instructions, or it can also be controlled in speed. During angle control, every time a pulse is input, the stator winding is switched once, and the output shaft rotates through an angle. The number of steps is consistent with the number of pulses. The angular displacement of the output shaft rotation is proportional to the input pulse. During speed control, continuous pulses are fed into the stepper motor windings, each phase winding is continuously energized in turn, and the stepper motor rotates continuously, and its rotational speed is proportional to the pulse frequency. Changing the energization sequence, that is, changing the rotation direction of the stator magnetic field, can control the motor to rotate forward or reverse.

1.3 Some typical application situations of stepper motors

①Stepper motors are mainly used in situations with positioning requirements. For example: wire cutting workbench dragging, hair transplanting machine workbench (pore positioning), packaging machine (fixed length). Basically it can be used in any situation involving positioning.

②Widely used in ATM machines, inkjet printers, cutting plotters, photo machines, spraying equipment, medical instruments and equipment, computer peripherals and mass storage equipment, precision instruments, industrial control systems, office automation, and robots and other fields. It is especially suitable for applications requiring smooth operation, low noise, fast response, long service life and high output torque.

③Stepper motors are widely used in textile machinery and equipment such as computer embroidery machines. The characteristics of this type of stepper motor are low maintaining torque, frequent starts, fast response speed, low operating noise, and low operating noise. Stable, good control performance, low overall machine cost.

Most of the stepper motors currently used in computer embroidery machines are three-phase hybrid stepper motors, and the use of subdivided drive technology can greatly improve the operating quality of the stepper motor, reduce torque fluctuations, and suppress oscillations. , reduce noise and improve step resolution.

1.4 The operating principle and structure of the stepper motor

The angular displacement can be controlled by controlling the number of pulses to achieve accurate positioning; the speed and acceleration of the motor rotation can also be controlled by controlling the pulse frequency to achieve speed regulation.

Under non-overload conditions, the motor's speed and stopping position only depend on the frequency and number of pulses of the pulse signal, and are not affected by load changes. That is, if a pulse signal is added to the motor, the motor will Turn a step angle. The existence of this linear relationship, coupled with the characteristics of the stepper motor that only has periodic errors and no cumulative errors.

1.5 Rotation

If phase A is energized and phases B and C are not energized, tooth 1 will be aligned with A due to the magnetic field (the rotor does not receive any force, the same below) . If phase B is energized and phases A and C are not energized, tooth 2 should be aligned with B. At this time, the rotor moves 1/3て to the right. At this time, tooth 3 and C are offset by 1/3て, and tooth 4 and A Offset(て-1/3て)=2/3て. If phase C is energized and phases A and B are not energized, tooth 3 should be aligned with C. At this time, the rotor moves 1/3 to the right, and tooth 4 is aligned with A by 1/3. If phase A is energized, phases B and C are not energized, teeth 4 are aligned with A, and the rotor moves 1/3 to the right.

In this way, after A, B, C, and A are energized respectively, tooth 4 (that is, the tooth before tooth 1) moves to phase A, and the motor rotor rotates one tooth pitch to the right. If you continue to press A , B, C, A? When energized, the motor will rotate to the right by 1/3 of each step (per pulse). If you press A, C, B, A? to energize, the motor will rotate in reverse direction. It can be seen that the position and speed of the motor have a one-to-one correspondence between the number of conductions (number of pulses) and frequency. The direction is determined by the conductive sequence.

2 Circuit design analysis

2.1 8253 and 8255 drive stepper motor circuit

①Connect the circuit as shown in the figure, use 8255 to output pulse sequence, switch K0~K6 Controls the speed of the stepper motor, and K7 controls the steering of the stepper motor. 8255 CS is connected to 288H~28FH. PA0~PA3 are connected to BA~BD; PC0~PC7 are connected to K0~K7.

②Programming: When a certain switch in K0~K6 is ?1? (dial up), the stepper motor starts, and the motor rotation speed is different. When K7 is turned upward, the motor rotates forward, and when turned downward, the motor rotates reversely.

2.2 Calculation of important experimental parameters

Based on the actual test, the stepcount is set to about 59 steps. The stepper motor makes one revolution.

According to the experimental requirements: first clockwise, 6 times per minute, for ten minutes. It is estimated that stepcount=59*6*10=3540.

Stop for three seconds: the 8086 machine cycle is 1/5MHz. 3s=1/5MHz*15*exp6 is an instruction of 15M machine cycles.

Then turn counterclockwise, 30 times per minute, for ten minutes. The estimated stepcount=59*30*10=17700.

　2.3 Practical problems and solutions

① I am not proficient enough in hardware connections and software programs. I checked the information in many aspects and read books to determine the design plan and the specific design content of the hardware and software.

②The control of the keyboard and LED display is not ideal enough. After careful interpretation of the program, the design purpose was finally achieved. Press key 10 to display 0. . . 0030, press key 12 to display 1. . . 0006, press key 14 to start running, press key 15 to stop running. ③The speed control is not accurate enough at first. After repeated testing, it was finally determined to be 59 steps per lap. And calculate the set number of steps of 6R/MIN and 30R/MIN.

3 Summary of experience

Since the operation of the stepper motor is controlled by electrical pulse signals, the angular displacement or linear displacement of the stepper motor is proportional to the number of pulses. Each time a pulse is given, the stepper motor rotates by an angle (step angle) or advances. / Take a step back, so hopefully you can clearly see this feature of the motor. By setting the pace and rotation speed, we can observe the motor's steps and the number of steps in one revolution.

References

1 Wang Zhongmin, et al. Principles of Microcomputers (2nd ed.). Xi'an: Xi'an University of Electronic Science and Technology Press, 2007

2 Jiang Xiaoan, Dong Xiufeng. Analog electronics (3rd ed.). Xi'an: Xi'an University of Electronic Science and Technology Press, 2009

3 Li Quanli. Microcontroller principles and interface technology. Beijing: Higher Education Press, 2010

Stepper Motor Control System

Han Hao

(Department of Physics and Mechanical and Electronic Engineering, Xi'an University of Arts and Sciences, Xi'an, Shaanxi 710000)

Abstract: As an actuator, stepper motor is one of the key products of mechatronics and is widely used in various automation control systems. With the development of microelectronics and computer technology, the demand for stepper motors is increasing day by day, and they are used in various fields of the national economy.

Keywords: stepper motor; actuator; computer; development

1 Principle and characteristics of stepper motor

1.1 Current development of stepper motor< /p>

Stepper motors are open-loop control components that convert electrical pulse signals into angular displacement or linear displacement. When the stepper driver receives a pulse signal, it drives the stepper motor to rotate a fixed angle (called "step angle") in the set direction, and its rotation runs step by step at a fixed angle. The angular displacement can be controlled by controlling the number of pulses to achieve accurate positioning; at the same time, the speed and acceleration of the motor rotation can be controlled by controlling the pulse frequency to achieve speed regulation. Under non-overload conditions, the motor's speed and stopping position only depend on the frequency and number of pulses of the pulse signal, and are not affected by load changes. That is, when a pulse signal is added to the motor, the motor will rotate through a step angle. The existence of this linear relationship, coupled with the characteristics of the stepper motor, only has periodic errors and no accumulated errors. It makes it very simple to use stepper motors to control speed, position and other control areas. The stepper motor can be used as a special motor for control. It is widely used in various open-loop controls by taking advantage of its characteristics of no accumulated error (accuracy of 100%).

1.2 Characteristics of stepper motors

1.3 Some typical application situations of stepper motors

1.4 The operating principle and structure of the stepper motor

The stepper motor is an actuator that converts electrical pulses into angular displacement. In layman's terms: when the stepper driver receives a pulse signal, it drives the stepper motor to rotate a fixed angle (and step angle) in the set direction. The angular displacement can be controlled by controlling the number of pulses to achieve accurate positioning; the speed and acceleration of the motor rotation can also be controlled by controlling the pulse frequency to achieve speed regulation.

1.5 Rotation

2.1 8253 and 8255 drive stepper motor circuit

①Connect the circuit as shown in the figure, use 8255 to output pulse sequence, switch K0~K6 to control the stepper motor speed, K7 Control stepper motor steering. 8255 CS is connected to 288H~28FH. PA0~PA3 are connected to BA~BD; PC0~PC7 are connected to K0~K7.

2.2 Calculation of important experimental parameters

Based on the actual test, the stepcount is set to about 59 steps. The stepper motor makes one revolution.

According to the experimental requirements: first clockwise, 6 times per minute, for ten minutes. It is estimated that stepcount=59*6*10=3540.

Stop for three seconds: the 8086 machine cycle is 1/5MHz. 3s=1/5MHz*15*exp6, which is an instruction of 15M machine cycles.

Then turn counterclockwise, 30 times per minute, for ten minutes. The estimated stepcount=59*30*10=17700.

2.3 Practical problems and solutions

③Speed ??control is not accurate enough at first. After repeated testing, it was finally determined to be 59 steps per lap. And calculate the set number of steps of 6R/MIN and 30R/MIN.

3 Summary of experience

First, use the Xingyan integrated environment software to edit and run the program, debug the experimental results on the STAR ES598PCI experimental instrument, and analyze the experimental program and hardware circuit; then, in When using the original source program for experiments, the motor speed control is not very obvious, which requires modifying the value of the control pace Takesetpcount and the frequency division number of 8253 to make the motor speed reach 6r/min and 30r/min. Secondly, adjust the 8259 control keyboard and display to finally display the speed and rotation direction in real time, and use the keyboard to control its start and stop. Since the operation of the stepper motor is controlled by electrical pulse signals, the angular displacement or linear displacement of the stepper motor is proportional to the number of pulses. Each time a pulse is given, the stepper motor rotates by an angle (step angle) or advances. / Take a step back, so hopefully you can clearly see this feature of the motor. By setting the pace and rotation speed, we can observe the motor's steps and the number of steps in one revolution.

References

1 Wang Zhongmin, et al. Principles of Microcomputers (2nd ed.). Xi'an: Xi'an University of Electronic Science and Technology Press, 2007

2 Jiang Xiaoan, Dong Xiufeng. Analog electronics (3rd ed.). Xi'an: Xi'an University of Electronic Science and Technology Press, 2009

3 Li Quanli. Microcontroller principles and interface technology. Beijing: Higher Education Press, 2010

Motor control technology paper Part 2

Acceleration and deceleration control of stepper motors

[Abstract] This article analyzes the stepper motor in detail Stepper motor and its working principle, and design the digital control system of stepper motor based on MCS-51 series microcontroller. The subdivision technology of stepper motors and constant frequency pulse width modulation technology are added to the design. Combined with the use of pulse divider, a simple subdivision drive control circuit was developed.

[Keywords] Stepper motor; Single chip microcomputer; Subdivision control

CLC number: F140 Document identification code: A Article number: 1009-914X(2015)40-0038 -01

1. Introduction

With the development of science and technology and the application of microelectronic control technology, stepper motors, as a kind of motor that can be precisely controlled, are widely used in high-precision applications. Processing machine tools, micro-robot control, aerospace satellites and other high-tech fields.

2. Principle of stepper motor

Stepper motor is a special motor for control. It cannot be operated by directly inputting AC or DC current like traditional motors. Instead, a pulse current needs to be input to control the rotation of the motor, so stepper motors are also called pulse motors. Its function is to convert the pulse electrical signal into the corresponding angular displacement or linear displacement, that is, given a pulse electrical signal, the motor will rotate an angle or move forward one step. According to the excitation method, it can be divided into three types: reactive, permanent magnet and hybrid. The reactive stepper motor is selected in this design, and its structure is shown in Figure 1.

This is the typical structure of a four-phase reactive stepper motor. ***There are 4 sets of stator control windings. One set of windings wound on two radially opposite magnetic poles is one phase. That is to say, the two opposite large teeth on the stator are one phase. The motor follows A-B-C Continuously turn on and off the control winding in the sequence of ―D―A?, and the rotor will continue to rotate step by step. Its speed depends on the frequency of energizing and de-energizing each control winding, that is, the input pulse frequency. The direction of rotation depends on the order in which each control winding is energized in turn.

3. Stepper motor drive control

Stepper motors cannot be directly connected to DC or AC power supply to work, and a special stepper motor drive controller must be used. Stepper motors and stepper motor drivers constitute a stepper motor drive system. The performance of the stepper motor drive system not only depends on the performance of the stepper motor itself, but also depends on the quality of the stepper motor driver.

There are many ways to drive stepper motors, including single voltage drive, dual voltage drive, chopper drive, subdivision drive, integrated circuit drive and bipolar drive. This design uses constant frequency pulse width modulation subdivision drive control method, which is a further improvement on the basis of chopper constant current drive. It can not only make the step angle after subdivision uniform, but also avoid complex calculations. .

IV. Design of constant frequency pulse width modulation subdivision circuit

1. Implementation of pulse distribution

In the microcontroller control of stepper motors, the control signal Produced by microcontroller. Its power-on commutation sequence strictly follows the working method of the stepper motor. Usually we call the process of power commutation as pulse distribution. In this design, the 8713 pulse distributor chip is used for power-on phase commutation control.

2. System control circuit design

The main circuit design of the stepper motor control system is shown in Figure 2.

As can be seen from the picture above, pins 5, 6, and 7 of the 8713 pulse distributor are all connected to high level, so this is a control that controls the four-phase stepper motor to operate according to four phases and eight beats. circuit. The P1.0 and P1.1 ports of the 8751 microcontroller are connected to pins 3 and 4 of the 8713 pulse distributor respectively. The P1.0 terminal of the 8751 microcontroller provides step pulses, and the P1.1 terminal controls the steering of the stepper motor. When it outputs high level, the stepper motor forwards; when it outputs low level, the stepper motor reverses. The microcontroller is still the main body of control. It outputs a 20kHz square wave through timer T0 and sends it to the D flip-flop as a constant frequency signal. At the same time, the square wave pulse signal output by the pulse output terminal of the 8713 pulse distributor is used as the control signal. Each change in its square wave voltage causes the rotor to rotate one step.

When the square wave pulse signal Ua output by the pulse output terminal of the 8713 pulse distributor remains unchanged, the rising edge of the constant frequency signal CLK causes the D flip-flop to output Ub high level, causing the switching tubes T1 and T2 to When it is turned on, the current in the winding increases, and the voltage drop across R2 on the sampling resistor increases. When this voltage drop is greater than Ua, the comparator outputs a low level, causing the D flip-flop to output Ub a low level, T1 and T2 are cut off, and the winding current decreases. This makes the voltage drop on R2 less than Ua, the comparator outputs a high level, causing the D flip-flop to output a high level, T1 and T2 are turned on, and the current in the winding rises again. This process is repeated, making the wave top of the winding current appear in a zigzag shape. Because the frequency of CLK is higher, the sawtooth ripple will be very small.

When Ua rises suddenly, the voltage drop on the sampling resistor is less than Ua, the current has a longer rise time, the current amplitude increases significantly, and rises by one stage, but since the output here is a square wave signal Instead of a staircase signal, there is only one rising stage, which means that this "staircase signal" only contains one stage. It does not subdivide each step into many steps, but makes the rising and falling slopes of the output pulse signal larger. The original square wave output is smoothed, and the control signal is smoothed like a trapezoid, as shown in Figure 3.

Similarly, when Ua drops suddenly, the voltage drop on the sampling resistor is greater than Ua for a long time, the comparator outputs a low level, and the rising edge of CLK will immediately clear the D flip-flop even if it outputs 1. zero. The power supply is always cut off, causing the current amplitude to drop significantly until it reaches a new stage.

The above process is repeated. Every time Ua changes, the rotor will rotate through one subdivision step.

One of the most prominent features of this circuit is that the pulse signal output by the 8713 pulse distributor replaces the ladder provided by the D/A converter in a typical constant frequency pulse width subdivision circuit. control signal. This design greatly simplifies the circuit and reduces the control difficulty of pulse distribution. Although the step wave signal is replaced by a square wave signal, the degree of subdivision during single-phase operation is reduced. However, since the four-phase windings of the stepper motor work in the same direction, the stepper motor subdivision can also be achieved. The purpose of drive control.

VI. Conclusion

Currently, the application of stepper motors is continuously penetrating into all aspects of daily life and industrial manufacturing, and research on stepper motors and their control technology at home and abroad has It is also making continuous progress. The mastery of this knowledge will have a very positive impact on future work and life.

References

[1] Wu Shouzhen, Zang Yingjie, etc. Pulse width modulation control technology of electric transmission [M]. Beijing: Machinery Industry Press, 2002.

[2] Wang Xiaoming. Single-chip microcomputer control of motors[M]. Beihang University Press, 2002.

[3] Editor-in-chief Li Jianzhong. Single-chip microcomputer principles and applications[M]. Xi'an: Xi'an Electronics University of Science and Technology Press, 2008.

[4] Editor-in-Chief Li Rending. Microcomputer Control of Motors[M]. Beijing: Machinery Industry Press, 2004.

[5] Huang Yong, Liao Yu, Gao Lin. Design of stepper motor motion control system based on single-chip microcomputer [J]. Electronic Measurement Technology, 2008, 31(5): 150-154.

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