阅读说明：本技术 一种主轴定位方法 (Main shaft positioning method ) 是由 高宇航 李鹏飞 于 2019-09-11 设计创作，主要内容包括：本发明公开了一种主轴定位方法。它包括：在电机轴的非轴承端增设一个绝对值编码器,绝对值编码器接A、<Image he="71" wi="76" file="DDA0002199762190000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>B、<Image he="66" wi="49" file="DDA0002199762190000012.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>四根线到变频器上的编码器接口对应位置；在负载端设置一个挡块,在挡块附近固定设置一个电磁接近开关；将电磁接近开关的信号线接入到变频器DI接口板的DI6上；在PLC控制器上编制一个主轴定位控制程序,通过PLC控制器与ACS800变频器协同控制主轴旋转并定位。本发明提供了一种针对ACS800变频器与AC450PLC控制器或其它型号的PLC控制器协同进行主轴定位的更合理更精准的主轴定位方法。应用该定位方法定位非常准确,每次都能将负载准确停在电磁接近开关所在的设定位置,极少有误差,实际应用效果好。(The invention discloses a main shaft positioning method. It includes: an absolute value encoder is additionally arranged at the non-bearing end of the motor shaft and is connected with A, B, and four wires are connected to the corresponding positions of encoder interfaces on the frequency converter; a stop block is arranged at the load end, and an electromagnetic proximity switch is fixedly arranged near the stop block; connecting a signal wire of the electromagnetic proximity switch to DI6 of a DI interface board of the frequency converter; a main shaft positioning control program is programmed on the PLC, and the PLC and the ACS800 frequency converter cooperatively control the rotation and positioning of the main shaft. The invention provides a more reasonable and accurate spindle positioning method for the spindle positioning of the ACS800 frequency converter and the AC450PLC or other types of PLC. The positioning method is very accurate in positioning, the load can be accurately stopped at the set position where the electromagnetic proximity switch is located every time, errors are few, and the practical application effect is good.)

1. A main shaft positioning method is characterized in that a PLC controller is connected with a frequency converter, the frequency converter is connected with a motor, and a bearing end of a motor shaft is connected with a loaded main shaft through a gear and a reduction gearbox; the frequency converter is an ACS800 frequency converter; an absolute value encoder is additionally arranged at the non-bearing end of the motor shaft and is connected with A, B, and four wires are connected to the corresponding positions of encoder interfaces on the frequency converter; a stop block is arranged at the load end, and an electromagnetic proximity switch is fixedly arranged near the stop block; connecting a signal wire of the electromagnetic proximity switch to DI6 of a DI interface board of the frequency converter; a main shaft positioning control program is programmed on the PLC, and the rotation and positioning of the main shaft are controlled by the cooperation of the PLC and the ACS800 frequency converter;

The main shaft positioning control program comprises the following steps:

(1) Determining whether the current main shaft position is positioned in front of or behind the electromagnetic proximity switch according to an encoder value sent by the frequency converter; if it is forward, the encoder value is greater than zero, otherwise it needs to be converted to a positive number by adding a full circle value. In order to reduce the encoder value error caused by gear clearance as much as possible, an offset is set for compensating the encoder precision;

(2) Setting an interval range needing positioning; when the encoder value is in the interval when the positioning is finished, the positioning is considered to be successful;

(3) setting zero position reference, and continuously subtracting the actual position at the current moment from the actual position at the last moment in the program; because the encoder value is cleared when the electromagnetic proximity switch is touched, the difference value is inevitably and suddenly increased at the moment of touching, and when the difference value is greater than the zero position reference, the load end is considered to touch the electromagnetic proximity switch, namely the zero position is reached;

(4) setting a zero-position visual signal which is used for judging that the electromagnetic proximity switch is contacted for a plurality of times at present, wherein according to the principle, the zero position is contacted for the first time and used for finding a confirmed position, so that under the normal condition, when the zero position is contacted for the second time and the speed is less than a set value, the positioning is regarded as successful;

(5) selecting a speed calculation formula 1, namely a formula 1-1, or a speed calculation formula 2, namely a formula 1-2 according to whether the residual angular displacement is greater than the speed switching value; if yes, selecting formula 1; if not, selecting a formula 2; and calculating the angular velocity based thereon;

(6) Determining which speed set value is selected according to whether the zero visual signal is equal to 1 or not; if yes, selecting the calculated angular speed as a speed set value; if not, selecting a certain specific numerical value, namely a fixed value, as a speed set value; sending the determined speed set value to a frequency converter for control;

(7) When the actual speed value returned by the frequency converter is smaller than a certain specific numerical value and the actual position of the main shaft falls within the range of the set interval, the main shaft is considered to be successfully positioned; otherwise, repeatedly executing the steps;

the velocity calculation equation 1 is:

Wherein v is angular velocity, a is angular acceleration, and x is angular displacement;

The velocity calculation equation 2 is:

Kx (formula 1-2)

Where v is the angular velocity, k is the proportionality coefficient, and x is the angular displacement.

2. The spindle positioning method according to claim 1, wherein in the step (2), the interval range is set to 99.94% to 0.06%.

3. the spindle positioning method according to claim 2, wherein the specific value in the above step (6) and step (7) is 500.

4. A method of positioning a spindle as claimed in claim 1, 2 or 3, wherein the PLC controller is an AC450PLC controller or other type of PLC controller.

5. A spindle positioning method according to claim 4 wherein the AC450PLC controller is connected to an ACS800 inverter, the ACS800 inverter is connected to a motor, the bearing end of the motor shaft is connected to the spindle of the load through a gear and a reduction gearbox; a spindle positioning control program is programmed on the AC450PLC controller, and the rotation and the positioning of the spindle are controlled by the cooperation of the AC450PLC controller and the ACS800 frequency converter.

6. The spindle positioning method according to claim 1, 2 or 3,

The parameters of the frequency converter are reset as follows:

7. A method of positioning a spindle as claimed in claim 1, 2 or 3, wherein the loading comprises: rolling mills, shears, chippers, numerically controlled machines, paper machines, printing presses, coilers.

Technical Field

the invention belongs to the technical field of industrial automatic control, and relates to a main shaft positioning method.

Background

In the industrial automatic production process of steel mills, metal processing plants, paper-making and printing plants, plastic plants and the like, various large-scale machine equipment (rolling mills, shearing machines, cutting machines, numerical control machines, paper machines, printing machines, coiling machines and the like) are commonly used, the large-scale machine equipment (also called loads) is usually driven by a motor reducer, the operation of the large-scale machine equipment is controlled by a PLC (programmable logic controller), the speed is regulated by a frequency converter, and the structure and the connection relation are as follows: the PLC controller is connected with a frequency converter, the frequency converter is connected with a motor, and the bearing end of a motor shaft is connected with a main shaft of a load (a rolling mill and the like) through a gear and a reduction gearbox; the working principle is that a PLC controls a motor reducer to drive a main shaft to rotate, and then the main shaft drives a load to run. In the process of driving the main shaft to rotate to drive the machine tool to operate by controlling the motor reducer by the PLC, the speed needs to be regulated by the frequency converter, and the main shaft is positioned in cooperation with the PLC. The frequency converter for positioning the main shaft requires a high-performance current vector control technology, can perform accurate position control in cooperation with the PLC, can start and stop quickly, has good dynamic response, high positioning speed, accurate speed regulation and accurate positioning, and can realize accurate positioning of the main shaft.

the ABB AC450PLC (programmable logic controller) has been widely used in the industrial automation production fields such as steel mills, metal processing plants, paper printing plants, plastic plants, etc. because of its good performance. The ABB ACS880 frequency converter is a novel high-performance frequency converter which can be used for accurately regulating the speed of a 160KW heavy load, but the frequency converter (ABB ACS880 frequency converter) of the type and an ABB AC450PLC (programmable logic controller) or other types of PLCs for carrying out main shaft positioning in a coordinated mode are not used in the prior art. According to the current application example of a certain steel mill, the actual effect of the currently used solution for performing spindle positioning by using the ACS800 frequency converter and the AC450PLC together is not ideal (positioning is not accurate), and therefore, a more reasonable and accurate spindle positioning method needs to be researched and designed.

disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a more reasonable and accurate spindle positioning method for the spindle positioning of the ACS800 frequency converter and the AC450PLC or other types of PLC in a cooperative manner.

The purpose of the invention is realized by the following technical scheme:

The invention discloses a main shaft positioning method, which comprises the following steps: the PLC controller is connected with a frequency converter, the frequency converter is connected with a motor, and the bearing end of a motor shaft is connected with a main shaft of a load (a rolling mill and the like) through a gear and a reduction gearbox; the frequency converter is an ACS800 frequency converter; an absolute value encoder (a sensor for measuring the rotation angle of the main shaft) is additionally arranged at the non-bearing end of the motor shaft, and the absolute value encoder is connected with A, B, and four wires are connected to the corresponding positions of an encoder interface on the frequency converter; a stop block is arranged at the load end, an electromagnetic proximity switch is fixedly arranged near the stop block, and the electromagnetic proximity switch can be fixed on a rack or other fixed positions; connecting a signal wire of the electromagnetic proximity switch to DI6 of a DI interface board of the frequency converter; the signal wire of the electromagnetic proximity switch is connected to DI6 of a DI interface board of the frequency converter; a main shaft positioning control program is programmed on the PLC, and the rotation and positioning of the main shaft are controlled by the cooperation of the PLC and the ACS800 frequency converter;

The main shaft positioning control program comprises the following steps:

(1) Determining whether the current main shaft position is positioned in front of or behind the electromagnetic proximity switch according to an encoder value sent by the frequency converter; if it is forward, the encoder value is greater than zero, otherwise it needs to be converted to a positive number by adding a full circle value. To minimize encoder value errors due to gear backlash, an offset is set to compensate for encoder accuracy.

(2) Setting an interval range needing positioning (the interval range can be set to be 99.94-0.06%); when the encoder value falls within the interval at the end of the positioning, the positioning is considered successful.

(3) The Zero position reference (Zero _ detect _ ref) is set and the program continuously differentiates the Actual position Actual _ pos _2(k) at the current time from the Actual position Actual _ pos _2(k-1) at the previous time. Since the encoder value is cleared when the electromagnetic proximity switch is touched, the difference value will tend to increase suddenly at the moment of touch, and when the difference value is greater than the zero position reference, the load end is considered to have touched the electromagnetic proximity switch (reached the zero position).

(4) And setting a zero-position visual signal which is used for judging that the electromagnetic proximity switch is contacted for a plurality of times at present, wherein according to the principle, the zero position is contacted for the first time and used for finding the confirmed position, so that under the normal condition, when the zero position is contacted for the second time and the speed is less than the set value, the positioning is regarded as successful.

(5) Selecting a speed calculation formula 1 (namely formula 1-1) or a speed calculation formula 2 (namely formula 1-2) according to whether the residual angular displacement is greater than a speed switching value (SlowIn _ Pos); if yes, selecting formula 1; if not, selecting a formula 2; and calculating the angular velocity based thereon;

(6) Determining which speed set value is selected according to whether the zero visual signal is equal to 1 or not; if yes, selecting the calculated angular speed as a speed set value; if not, a certain specific value, i.e. a fixed value (500 in the embodiment) is selected as the speed set value; and sending the determined speed set value to a frequency converter (for control).

(7) When the actual speed value returned by the frequency converter is less than a certain specific value (500 in the embodiment) and the actual position of the main shaft falls within the range of the set interval, the main shaft is considered to be successfully positioned; otherwise, the above steps are repeatedly executed.

The velocity calculation equation 1 is:

where v is the angular velocity, a is the angular acceleration, and x is the angular displacement.

the velocity calculation equation 2 is:

Kx (formula 1-2)

where v is the angular velocity, k is the proportionality coefficient, and x is the angular displacement.

The concept and main principle of the invention are as follows:

The positioning of the spindle is to ensure that the motor stops with the spindle in a fixed interval each time the operation is performed. To achieve this, the spindle speed needs to be controlled so that the displacement approaches 0 while the speed decreases until it stops.

when the main shaft rotates past the electromagnetic proximity switch for the first time, the main shaft is known to be just one complete period away from the parking position at the moment, namely the residual angular displacement is known. The rotational motion of the main shaft is uniform acceleration, and the angular velocity can be calculated by the velocity calculation formula 1 (i.e., formula 1-1) by knowing the angular acceleration and the angular displacement from high school physics knowledge, thereby calculating the rotational velocity of the main shaft.

The velocity calculation equation 1 is:

where v is the angular velocity, a is the angular acceleration, and x is the angular displacement.

however, when the angular displacement x (in this example, Ref _ Act _ Pos, see fig. 2 in detail) is small, the speed change is not obvious, and the motor is likely to be rotated at a low speed. To solve this problem, it is known from high school mathematics that when x is small, a quadratic function can be approximately regarded as a linear function, and therefore, a velocity calculation formula 2 (i.e., formula 1-2) is introduced, and the rotation speed of the spindle when the angular displacement is small can be obtained by formula 2.

The velocity calculation equation 2 is:

Kx (formula 1-2)

Where v is the angular velocity, k is the proportionality coefficient, and x is the angular displacement.

Further, the PLC controller is an AC450PLC controller or other types of PLC controllers.

Further, the AC450PLC controller is connected with an ACS800 frequency converter, the ACS800 frequency converter is connected with a motor, and the bearing end of the motor shaft is connected with a load (a rolling mill and the like) through a gear and a reduction gearbox; a spindle positioning control program is programmed on the AC450PLC controller, and the rotation and the positioning of the spindle are controlled by the cooperation of the AC450PLC controller and the ACS800 frequency converter.

Further, the parameters of the frequency converter are reset (namely, the function codes are added), and the parameters preset by the frequency converter from the factory are not adopted. The reconfigured converter parameters are shown in table 1-1. The frequency converter parameter block diagram is shown in detail in fig. 1. The logic relationship between the frequency converter parameters and the program is detailed in tables 1-3.

TABLE 1-1 partial parameter table of frequency converter

Parameter number	Set value	Remarks for note
			10.1	DI State	Transmitting data
6.100	user control word 1	receiving data
			61.62	10.1	data 3 selection in dataset 17
62.52	6.100	Data 1 selection in dataset 12
			90.59	0	position counter integer initial value signal source
90.63	4096	Feedback constant numerator
			90.67	DI6	Position counter initial command signal source
90.68	6.100.10	inhibit position counter initialization
			90.69	6.100.11	Reset position counter initialization
92.10	1024	Pulse/revolution number

The invention has the beneficial effects that:

the invention provides a more reasonable and accurate spindle positioning method for the spindle positioning of the ACS800 frequency converter and the AC450PLC or other types of PLC. The method is a new application on the novel frequency converter.

according to the field practical application effect feedback of a plurality of tests and practical applications (applied for half a year) performed in a certain steel mill, the main shaft positioning method has very accurate positioning, and the load can be accurately stopped at the position (set position) of the electromagnetic proximity switch every time, so that errors are few. The spindle positioning method has excellent practical application effect.

Drawings

FIG. 1 is a logic diagram of the frequency conversion parameters associated with the ACS800 frequency converter and encoder of the present invention;

Fig. 2 is a program logic block diagram of a spindle positioning control program in the present invention.

Detailed Description

the invention is further described below with reference to the following figures and examples.