CN112678468A

CN112678468A - Rolling machine and positioning method thereof

Info

Publication number: CN112678468A
Application number: CN202011472663.5A
Authority: CN
Inventors: 顾和祥; 高争华; 曾斌
Original assignee: Siemens Ltd China
Current assignee: Siemens Ltd China
Priority date: 2020-12-15
Filing date: 2020-12-15
Publication date: 2021-04-20
Anticipated expiration: 2040-12-15
Also published as: CN112678468B

Abstract

The embodiment of the application provides a rolling machine and a positioning method of the rolling machine. The rolling machine comprises a motor and a positioning control system, and the control unit is used for: in the running process of the motor, if a trigger signal sent when the position detection piece is triggered is received, a passive zero returning action is executed, so that the real-time position detected by the encoder at the current moment is determined as a position zero point; entering a position positioning mode, and acquiring a target control speed and a positioning distance corresponding to the position positioning mode, wherein the positioning distance is used for indicating the distance between a target positioning position and a positioning zero point; and controlling the motor according to the positioning distance, the target control speed and the real-time position of the relative positioning zero point detected by the encoder so as to position the conveying object corresponding to the motor to the target positioning position. The positioning cost of the rolling machine is lower.

Description

Rolling machine and positioning method thereof

Technical Field

The embodiment of the application relates to the field of mechanical equipment, in particular to a rolling machine and a positioning method of the rolling machine.

Background

In industrial production, some production processes need to be repeatedly positioned, and the positioning accuracy needs to be ensured. Taking a high-speed roller machine used in the automobile production process as an example, the high-speed roller machine is used for conveying production materials at fixed points in an automatic continuous production line of automobiles. For example, in a welding process, a high-speed roller machine conveys materials to different welding stations so that a welding robot can weld.

In order to ensure the production efficiency, the high-speed roller machine is required to have higher conveying speed, so that the positioning precision of the high-speed roller machine is difficult to ensure. For example, in the prior art, two encoders are used for positioning control of a high-speed rolling machine, but this method not only needs a large number of encoders, resulting in high control cost and further increased production cost, but also is difficult to perform accurate positioning for some scenes which are not suitable for mounting the encoders.

Disclosure of Invention

In order to solve the above problems, embodiments of the present application provide a rolling machine and a positioning method of the rolling machine, so as to at least partially solve the above problems.

According to a first aspect of the embodiments of the present application, a rolling machine is provided, the rolling machine includes a motor and a positioning control system, the positioning control system is connected to the motor to control the motor to drive a conveying object to move and position, the positioning control system includes a control unit, a position detecting member and an encoder, the control unit is respectively connected to the position detecting member and the encoder, the encoder is connected to the motor and detects a real-time position of the motor relative to the conveying object, the position detecting member is disposed on a moving path of the conveying object driven by the motor and sends a trigger signal to the control unit when the conveying object passes through; the control unit is used for: in the running process of the motor, if a trigger signal sent when the position detection piece is triggered is received, a passive zero returning action is executed, so that the real-time position detected by the encoder at the current moment is determined as a position zero point; entering a position positioning mode, and acquiring a target control speed and a positioning distance corresponding to the position positioning mode, wherein the positioning distance is used for indicating the distance between a target positioning position and a positioning zero point; and controlling the motor according to the positioning distance, the target control speed and the real-time position of the relative positioning zero point detected by the encoder so as to position the conveying object corresponding to the motor to the target positioning position.

Optionally, the positioning control system further includes a programmable logic controller, the control unit includes a frequency converter, the frequency converter is respectively connected to the motor, the encoder, the position detecting element and the programmable logic controller, and the frequency converter is further configured to: sending a notification message to a connected programmable logic controller according to the trigger signal, wherein the notification message is used for indicating that the frequency converter is executing a passive zero returning action; and the position positioning entering instruction is obtained, responds to the position positioning entering instruction sent by the notification message, is used for indicating to enter a position positioning mode and carries the target control speed and the positioning distance.

Optionally, the notification message includes a status word for indicating monitoring positioning, and a set bit in the status word is used to indicate whether a passive zero-returning action is being performed.

Optionally, the frequency converter includes an IO terminal, the position detection element is connected to the IO terminal to input a signal to the IO terminal, the IO terminal is configured to periodically sample the input signal, and a time interval between two adjacent sampling periods is less than 1 millisecond.

Optionally, the frequency converter is further configured to enter a speed control mode before a trigger signal sent when the position detection element is triggered is received and a passive zero-returning action is executed, where the speed control mode carries set speed information corresponding to the motor, and the motor is controlled according to the set speed information, so that the running speed of the motor is matched with the set speed information.

According to another aspect of the present application, there is provided a method for controlling and positioning a rolling machine, the method being applied to a positioning control system of a rolling machine for controlling a motor of the rolling machine, the positioning control system including a control unit, an encoder and a position detecting member, the encoder being disposed on the motor, the method being particularly applied to the control unit, the position detecting member being configured to detect whether a conveying object driven by the motor passes through, the method including: in the running process of the motor, if a trigger signal sent when the position detection piece is triggered is received, a passive zero returning action is executed, so that the real-time position detected by the encoder at the current moment is determined as a position zero point; entering a position positioning mode, and acquiring a target control speed and a positioning distance corresponding to the position positioning mode, wherein the positioning distance is used for indicating the distance between a target positioning position and a positioning zero point; and controlling the motor according to the positioning distance, the target control speed and the real-time position of the relative positioning zero point detected by the encoder so as to position the conveying object corresponding to the motor to the target positioning position.

Optionally, entering a position location mode, and acquiring a target control speed and a location distance corresponding to the position location mode, includes: sending a notification message, wherein the notification message is used for indicating that the passive zero returning action is being executed; acquiring a position positioning entering instruction responding to the notification message; and entering a position positioning mode according to the position positioning entering instruction, and acquiring a target control speed and a positioning distance corresponding to the position positioning mode from the position positioning entering instruction.

Optionally, before the passive zero-returning action is executed if a trigger signal sent when the position detecting element is triggered is received, the method further includes: entering a speed control mode, wherein the speed control mode carries set speed information which is used for indicating the running speed of the motor; and controlling the motor according to the set speed information so that the running speed of the motor is matched with the set speed information.

Optionally, before the passive zero-returning action is executed if a trigger signal sent when the position detecting element is triggered is received, the method further includes: the IO terminal is connected with the position detection piece so as to receive a signal input by the position detection piece and periodically sample the input signal, and the time interval between two adjacent sampling periods of the IO terminal is less than 1 millisecond.

According to the roller machine provided by the embodiment of the application, the passive zero (fly) can be understood as re-determining the position zero point detected by the encoder in the control unit during the operation of the motor. This passive zero-return action is not generated by a zero-return command, but is performed on the basis of a trigger signal sent when the position detection member is triggered. Realized from this, when carrying the object and passing through position detection spare, the real-time position that detects with the encoder at present moment confirms as position zero point to when subsequent fixes a position in position location mode, fix a position according to the position zero point of confirming again, thereby eliminated and carried the object in the detection error of encoder accumulation in the stroke before triggering position detection spare, in order to avoid the adverse effect of accumulative error to follow-up control, guarantee follow-up accuracy when controlling the motor according to the position, thereby guarantee the accuracy to carrying the object location. The positioning control system capable of realizing the passive zero returning action is applied to the high-speed rolling machine, so that the positioning precision is ensured, an encoder is omitted, the positioning and control cost is saved, and the cost can be greatly reduced particularly in the high-speed rolling machine with more stations. In addition, the used encoder is reduced, the installation difficulty and the installation cost of the encoder can be reduced, and the problems that the motor control shakes and the rolling machine vibrates greatly and the like due to poor installation of the encoder are effectively solved.

Drawings

The drawings are only for purposes of illustrating and explaining the present application and are not to be construed as limiting the scope of the present application. Wherein the content of the first and second substances,

FIG. 1 shows a schematic structural view of a roller bed according to an embodiment of the present application;

fig. 2 shows a schematic diagram of a moving process of a transport object according to an embodiment of the application;

FIG. 3 shows a schematic diagram of a positioning control system of a rolling machine according to an embodiment of the present application

FIG. 4 shows a schematic flow chart of steps of a positioning method according to an embodiment of the present application;

fig. 5 is a flowchart illustrating steps of a positioning method using a scene according to an embodiment of the present application.

Description of reference numerals:

10. a bed body; 20. a skid; 30. a roller; 40. a motor; 50. an encoder; 70. a frequency converter; 80. a programmable logic controller; 90. a position detecting member.

Detailed Description

In order to more clearly understand the technical features, objects and effects of the embodiments of the present application, specific embodiments of the present application will be described with reference to the accompanying drawings.

Referring to fig. 1, fig. 1 shows a schematic structural view of a rolling machine according to an embodiment of the present invention.

Among them, the high-speed rolling machine is taken as an example, and compared with a common rolling machine, the moving speed of the conveyed object in the high-speed rolling machine is higher, so that the conveying efficiency is higher. For example, if the moving speed of the transport object is 1m/s or more, it can be considered as a high-speed rolling machine.

As shown in fig. 1, in the present embodiment, the high-speed rolling machine includes a bed 10, a skid 20, a roller 30, and the like, in addition to a motor 40 and a positioning control system. Wherein, the roller 30 is rotatably disposed on the bed 10, and the motor 40 is disposed on the bed 10 and connected with the roller 30, thereby driving the roller 30 to rotate. Skid 20 is movably disposed on roller 30 as a conveying object, and skid 20 is driven to move during rotation of roller 30, thereby conveying skid 20 and the material on skid 20 to a desired position. The positioning control system is used for controlling the motor 40, so that the moving speed and the stop position of the skid 20 are controlled by controlling the running speed and the start and stop of the motor 40, and the positioning is realized.

The positioning control system comprises a control unit, a position detection piece 90 and an encoder 50, wherein the control unit is respectively connected with the position detection piece 90 and the encoder 50, the encoder 50 is connected with the motor 40 and detects the real-time position of the motor 40 relative to a conveyed object, the position detection piece 90 is arranged on a moving path of the conveyed object driven by the motor 40 and sends a trigger signal to the control unit when the conveyed object passes through. The control unit is used for: in the running process of the motor, if a trigger signal sent when the position detection piece is triggered is received, a passive zero returning action is executed, so that the real-time position detected by the encoder at the current moment is determined as a position zero point; entering a position positioning mode, and acquiring a target control speed and a positioning distance corresponding to the position positioning mode, wherein the positioning distance is used for indicating the distance between a target positioning position and a positioning zero point; and controlling the motor according to the positioning distance, the target control speed and the real-time position of the relative positioning zero point detected by the encoder so as to position the conveying object corresponding to the motor to the target positioning position.

Here, the passive zero (fly timing) is understood to be the position zero detected by the encoder 50 that is determined again in the control unit during the operation of the motor 40. This passive zero-return action is not generated by a zero-return command, but is performed based on a trigger signal sent when the position detection member 90 is triggered. Realized from this, when carrying the object and passing through position detection piece 90, the real-time position determination that will the present moment encoder 50 detect is position zero point to when subsequent fixes a position the mode and fixes a position according to the position zero point of confirming again, thereby eliminated and carried the object in the stroke before triggering position detection piece 90 encoder 50 accumulative detection error, in order to avoid accumulative error to the adverse effect of follow-up control, guarantee follow-up accuracy when controlling motor 40 according to the position, thereby guarantee the accuracy to carrying the object location.

The positioning control system capable of realizing the passive zero returning action is applied to the high-speed rolling machine, so that the positioning precision is ensured, an encoder is omitted, the positioning and control cost is saved, and the cost can be greatly reduced particularly in the high-speed rolling machine with more stations. In addition, the used encoder is reduced, the installation difficulty and the installation cost of the encoder can be reduced, and the problems that the motor control shakes and the rolling machine vibrates greatly and the like due to poor installation of the encoder are effectively solved.

The control unit enters a position locating mode after passive zero returning action, and controls the motor 40 based on the real-time position, the target control speed and the locating distance detected by the encoder 50 in the position locating mode so as to ensure that a conveying object driven by the motor 40 can be accurately located at the target locating position indicated by the locating distance, and the conveying efficiency is also ensured besides the locating accuracy because the motor 40 is controlled according to the target control speed.

Alternatively, the motor 40 may be an asynchronous motor. The real-time speed of the motor 40 is read by the encoder 50, and the real-time position is calculated.

The position detecting member 90 is disposed on a moving path of a conveying object (e.g., the skid 20) driven by the motor 40, and detects whether the conveying object passes through the position detecting member 90. And in order to guarantee detection accuracy and sensitivity, position detection piece 90 can be photoelectric switch, and photoelectric switch not only can guarantee the sensitivity that detects, can realize contactless detection moreover, effectively reduces wearing and tearing, promotes life.

Of course, the position detector 90 may be any other device capable of detecting the position of the conveyance object and generating the trigger signal. For example, the position detector 90 may be a proximity switch or a micro-switch.

Alternatively, the control unit may include a frequency converter 70, and the frequency converter 70 performs the above-mentioned actions to control the motor, or the control unit may include a programmable logic controller, and the actions are performed by the programmable logic controller to control the motor, or the control unit includes the frequency converter 70, and the positioning control system further includes a programmable logic controller 80, and the frequency converter 70 and the programmable logic controller 80 can communicate with each other to realize driving and controlling of the motor.

Fig. 2 shows a simplified schematic diagram of a process of conveying a conveying object, wherein the conveying object moves from a starting position I to a target positioning position II, and a position detecting element 90 is arranged at a mounting position III, which is located between the starting position I and the target positioning position II. When the conveying object passes the position detecting member 90, the position detecting member 90 is triggered to transmit a trigger signal.

The following description will be made of a process of the rolling machine implementing the process shown in fig. 2, in which the positioning control system further includes a programmable logic controller 80, the control unit includes a frequency converter 70, the frequency converter 70 is respectively connected to the motor 40, the encoder 50, the position detecting element 90 and the programmable logic controller 80, and the following description is made:

in order to ensure that the frequency converter 70 can receive the trigger signal sent by the position detection element 90 in time, the frequency converter 70 includes an IO terminal, the position detection element 90 is connected with the IO terminal to input a signal to the IO terminal, the IO terminal is used for periodically sampling the input signal, and a time interval between two adjacent sampling periods is less than 1 millisecond. Because the time interval between two adjacent sampling periods of the IO terminal is less than 1 millisecond, the timeliness of the detection of the IO terminal is ensured, and the received trigger signal can be known in time, so that the real-time position detected by the encoder 50 is determined in time, and the real-time position is determined as the position zero point.

In order to ensure the conveying efficiency, in the process of moving the conveying object from the initial position I to the installation position III corresponding to the position detecting element 90, the frequency converter 70 may enter a speed control mode, the speed control mode carries the set speed information corresponding to the motor 40, and the motor 40 is controlled according to the set speed information, so that the running speed of the motor 40 is matched with the set speed information.

When the frequency converter 70 is in the speed control mode, the motor 40 may be driven to move at the operation speed indicated by the set speed information, so as to ensure the conveying efficiency of the conveyed object, and thus ensure the processing efficiency.

However, the conveyed object moves to the position detecting element 90 and triggers the position detecting element 90, the position detecting element 90 sends a trigger signal to the frequency converter 70, and the frequency converter 70 receives the trigger signal and executes a passive zero-returning action. In addition, the frequency converter 70 is also used for: sending a notification message to the connected programmable logic controller 80 according to the trigger signal, wherein the notification message is used for indicating that the frequency converter 70 is executing the passive zero returning action; the acquisition plc 80 responds to the position location entry instruction sent by the notification packet, where the position location entry instruction is used to indicate entry into a position location mode and carries a target control speed and a location distance.

The format of the notification message and the manner of communication between the transducer 70 and the programmable logic controller 80 may be determined as desired. For example, the frequency converter 70 and the programmable logic controller 80 are connected via a profinet network and communicate with each other. In this embodiment, the notification message includes a status word for indicating monitoring positioning, and a set bit in the status word is used to indicate whether a passive zero-returning action is being performed. The set bit may be determined as needed, for example, the 12 th bit, and when the 12 th bit of the status word is "1", it indicates that the frequency converter 70 is performing the passive zero-returning action; when the 12 th bit of the status word is "0", it indicates that the frequency converter 70 does not perform the passive zero-returning action.

The frequency converter 70 is connected to the programmable logic controller 80, and after the frequency converter 70 receives the trigger signal, the notification message informs the programmable logic controller 80 that the frequency converter 70 is performing the passive zero-returning action, and in response to the notification message, the programmable logic controller 80 can instruct the frequency converter 70 to enter a position locating mode to achieve accurate location of the transported object.

The position positioning entering instruction carries a target control speed and a positioning distance, and the positioning distance indicates the distance between a target positioning position and the mounting position III. The target control speed may be an operation speed indicated by the set speed information as long as the requirement of the conveying efficiency can be satisfied.

Taking the maximum weight of skid 20 and load as 1800kg (kilogram) and the travel pitch as 6m (meter), if the transportation time needs to be controlled within 6s (second), the running speed can be 1.5 m/s. Compared with the common low-speed roller machine, the conveying time is more than 10s, and the conveying efficiency of the high-speed roller machine is improved.

Due to the increase of the operation speed, a longer deceleration time or a larger braking friction force is needed during positioning, and under the condition that the structure of the high-speed rolling machine is determined, the maximum friction force which can be provided by the high-speed rolling machine is determined, so that the position detection piece 90 needs to be arranged at a proper position during positioning, the requirement on conveying efficiency is met, overshoot is avoided, and the positioning accuracy is ensured.

If the distance between the position detecting member 90 and the target positioning position is too long, errors of the encoder 50 are accumulated, and positioning accuracy is affected, and if the distance between the position detecting member 90 and the target positioning position is too short, the conveyed object overshoots, and thus positioning cannot be performed accurately.

In the present embodiment, based on the formula of uniform acceleration:

it is understood that in the case of a defined operating speed v and acceleration a, the deceleration stroke s is defined. Therefore, as long as the distance (denoted as the distance L) between the mounting position III and the target positioning position II is greater than or equal to the deceleration stroke s, the overshoot can be avoided while the conveying efficiency is satisfied, and the smaller the distance between the mounting position III and the target positioning position II is, the smaller the error accumulation is, the better the control and positioning accuracy is, and the accurate positioning is realized. At the frequency converter 70And when the conveying object is in the position positioning mode, carrying out position control on the conveying object according to a positioning algorithm preset in the position positioning mode. For example, the predetermined operation speeds corresponding to different positions are determined according to the actual operation speed, the target control speed and the positioning distance of the motor 40, meanwhile, the actual operation speed is determined according to the difference between the real-time position detected by the encoder 50 and the target positioning position, and then the motor 40 is adjusted according to the difference between the predetermined operation speed and the actual operation speed, so that the target control speed can be met in the process that the conveying object driven by the motor 40 moves from the installation position III to the target positioning position II, and the conveying object is accurately stopped to the target positioning position (i.e., positioned to the target positioning position).

By innovatively applying the passive zero returning action on the high-speed rolling machine, the positioning cost is reduced under the condition of ensuring the positioning precision of the high-speed rolling machine. Compared with a mode of carrying out speed closed-loop and position closed-loop control by matching two encoders with the encoding ruler, the problem of shaking of the motor, the rolling machine and the like due to inaccurate matching of the encoders and the encoding ruler caused by installation errors of the encoders is solved.

According to another aspect of the present application, there is provided a control positioning method of a rolling machine, which is applied to a positioning control system of a rolling machine for controlling a motor of the rolling machine, the positioning control system including a control unit, an encoder 50, and a position detecting member 90, the method being particularly applied to the control unit, the encoder 50 being disposed on the motor 40, and the position detecting member 90 being used for detecting whether a conveying object driven by the motor 40 passes through.

The positioning method comprises the following steps: step S102: in the operation process of the motor 40, if a trigger signal sent when the position detecting element 90 is triggered is received, a passive zero returning action is executed, so as to determine the real-time position detected by the encoder 50 at the current moment as a position zero point; step S104: entering a position positioning mode, and acquiring a target control speed and a positioning distance corresponding to the position positioning mode, wherein the positioning distance is used for indicating the distance between a target positioning position and a positioning zero point; step S106: and controlling the motor 40 according to the positioning distance, the target control speed and the real-time position of the relative positioning zero point detected by the encoder 50 so as to position the conveying object corresponding to the motor 40 to the target positioning position.

The method is applied to a rolling machine and used for controlling the motor 40 in the rolling machine, and can perform passive zero returning action in the running process of the motor 40, so that the detection error accumulated by the encoder 50 in the stroke of a conveyed object before the position detection piece 90 is triggered is eliminated, the adverse effect of the accumulated error on subsequent control is avoided, the accuracy of the motor 40 in the subsequent control according to the position is ensured, and the accuracy of positioning the conveyed object is ensured.

Optionally, in order to ensure the conveying efficiency, before the step S102, the positioning method further includes a step S100a to a step S100 c.

Step S100 a: the IO terminal is configured to be connected to the position detection element 90 to receive a signal input from the position detection element 90 and to periodically sample the input signal.

In general, the IO terminal in the frequency converter 70 may be divided into a normal IO terminal and a fast IO terminal, the time interval between two adjacent sampling periods of the normal IO terminal detecting the input signal is usually ten or several tens of milliseconds, and the time interval between two adjacent sampling periods of the fast IO terminal is less than 1 millisecond. The IO terminal that is connected with position detection spare 90 in this embodiment is quick IO terminal, and when position detection spare 90 exported trigger signal to converter 70 like this, converter 70 can in time learn this trigger signal through quick IO terminal to in time carry out the action of returning to zero passively, with the accuracy of guaranteeing position zero.

In one possible approach, the IO terminal connected to position detector 90 is determined by configuring the value of the P488 terminal of transducer 70. For example, if the value of the P488 terminal is "25", the DI/DO terminal numbered 25 is connected to the position detector 90. The DI/DO terminal indicates that the terminal can be used as an input terminal (input) or an output terminal (output), and is used as an input terminal in this embodiment.

In addition, in order to ensure that the inverter 70 can reliably communicate with the position detector 90 and to avoid the position detector 90 from erroneously outputting a trigger signal to the inverter 70 when erroneously triggered, and thereby causing the inverter 70 to malfunction, the inverter 70 may be configured as follows: the value of the P2511 terminal in the frequency converter 70 is configured to be "0" so that the position detector 90 is effective at the rising edge of the signal; the value of the terminal of the inverter 70P2510 is configured to "0" to select the effective position detecting element 90.

When the motor 40 is driven and controlled by the inverter 70 after the inverter 70 is configured, the following steps S100b and S100c may be performed to ensure a good driving and controlling effect.

Step S100 b: and entering a speed control mode, wherein the speed control mode carries set speed information, and the set speed information is used for indicating the running speed of the motor 40.

The speed control mode can be suitable for the process that the conveying object driven by the motor 40 moves from the initial position I to the mounting position III corresponding to the position detection piece 90, the frequency converter 70 is in the speed control mode, and the running speed of the motor 40 is controlled, the control mode is not only simple in control, small in occupied computing capacity of the frequency converter 70, but also reliable in control, and the running speed of the motor 40 can be guaranteed, so that the conveying efficiency is guaranteed.

In one possible approach, the speed control mode may be implemented via a SETUP mode corresponding to the basic positioning function EPOS in the frequency converter 70.

The speed control mode carries set speed information indicating the operating speed of the motor 40. The set operating speed may be determined based on the desired transport efficiency or experience. For example, if the distance from the start position I to the target positioning position II is 6m (meters), and the transport time needs to be controlled within 6s (seconds) in order to satisfy the transport efficiency, the running speed indicated by the set speed information may be 1.5m/s (meters/second), but the running speed indicated by the set speed information may be other values depending on the transport efficiency, the acceleration performance and the deceleration performance of the motor 40.

Step S100 c: the motor 40 is controlled according to the set speed information so that the operation speed of the motor 40 matches the set speed information.

For example, in the speed control mode, the operation speed of the motor 40 is adjusted according to the set speed information. In this mode, it is only necessary to ensure that the operating speed of the motor 40 satisfies the set speed information, and the accuracy of the real-time position of the motor 40 detected by the limit encoder 50 is not required.

When the conveying object is driven by the motor 40 to move to the mounting position III of the position detecting member 90, the position detecting member 90 is triggered, the position detecting member 90 sends a trigger signal (for example, a rising edge signal is output to the connected IO terminal) to the inverter 70, and the inverter 70 executes the following steps S102 to S106.

Step S102: during the operation of the motor 40, if a trigger signal sent when the position detecting element 90 is triggered is received, a passive zero-returning action is performed to determine the real-time position detected by the encoder 50 at the current time as the position zero point.

When the frequency converter 70 receives the trigger signal, the real-time position detected by the encoder 50 at the present moment (the real-time position may be the real-time position of the conveying object relative to the motor 40) is determined as the new position zero point. This position zero point is used as a position zero point when position control is performed in the subsequent position control mode. On one hand, the error detected by the encoder 50 accumulated before can be eliminated by re-determining the position zero point, so that the accuracy and precision of the subsequent position control are ensured; on the other hand, accurate speed control and position control can be realized without using two encoders 50, which is more suitable for application scenarios in which the encoders 50 cannot be installed, and also saves one encoder 50 and reduces the cost.

Step S104: and entering a position positioning mode, and acquiring a target control speed and a positioning distance corresponding to the position positioning mode, wherein the positioning distance is used for indicating the distance between the target positioning position and a positioning zero point.

In one possible approach, if the positioning control system includes a programmable logic controller 80(PLC) or other host computer, step S104 includes the following processes:

process A: and sending a notification message, wherein the notification message is used for indicating that the passive zero returning action is being executed.

For example, transducer 70 sends a notification message to programmable logic controller 80 to inform programmable logic controller 80 that transducer 70 is performing a passive zeroing action.

The programmable logic controller 80 sends a position location entry instruction to the frequency converter 70 based on the notification message to instruct the frequency converter 70 to enter the position control mode. The position location entering command may carry information of parameters required by the position control mode, such as a location distance and a target location speed.

And a process B: and acquiring a position positioning entering instruction responding to the notification message.

The transducer 70 receives the position location entry command from the plc 80.

And a process C: and entering a position positioning mode according to the position positioning entering instruction, and acquiring a target control speed and a positioning distance corresponding to the position positioning mode from the position positioning entering instruction.

The position location mode may be an MDI mode (i.e., absolute location mode) in the frequency converter 70. The target control speed may be the operation speed indicated by the set speed information or may be a speed different from the operation speed determined as necessary. The positioning distance can be determined according to the required target positioning position. If the distance between the target positioning position II and the mounting position III of the position detecting member 90 is L, the positioning distance is set to L.

Step S106: and controlling the motor 40 according to the positioning distance, the target control speed and the real-time position of the relative positioning zero point detected by the encoder 50 so as to position the conveying object corresponding to the motor 40 to the target positioning position.

After the frequency converter 70 enters the position locating mode, the position of the conveyed object is controlled according to a locating algorithm preset in the position locating mode. For example, the predetermined operation speeds corresponding to different positions are determined according to the actual operation speed, the target control speed and the positioning distance of the motor 40, meanwhile, the actual operation speed is determined according to the difference between the real-time position detected by the encoder 50 and the target positioning position, and then the motor 40 is adjusted according to the difference between the predetermined operation speed and the actual operation speed, so that the target control speed can be met in the process that the conveying object driven by the motor 40 moves from the installation position III to the target positioning position II, and the conveying object is accurately stopped to the target positioning position (i.e., positioned to the target positioning position).

By the method, one encoder 50 is omitted, and compared with a mode of performing double closed-loop control on a speed loop and a position loop by using two encoders 50, one position encoder 50 can be omitted, so that the cost is saved; compared with a control mode without the position encoder 50, the method can realize accurate positioning, thereby meeting the requirements on precision and cost at the same time.

The method can be applied to equipment such as a high-speed rolling machine and the like, and the control of the motor 40 of the high-speed rolling machine is realized. Because the positioning control system comprises an encoder 50 and a position detection part 90, whether the conveyed object passes through can be detected through the position detection part 90, the control unit performs a passive zero returning action when the conveyed object passes through, the position zero point is determined again, and the motor 40 is controlled according to the real-time position detected by the encoder 50, so that the conveyed object is accurately positioned at the target positioning position. Thus, only one encoder 50 is needed, the cost is lower compared with the double closed-loop control using two or more encoders 50, the positioning control is more accurate, and the conveying efficiency can be well ensured.

According to the embodiment of the application, the positioning method has the following beneficial effects:

the position detection part 90 realizes the passive zero returning in the operation process of the motor 40, so that the position zero point is determined again and is used as the position zero point when the subsequent position positioning mode is used for positioning, and the accuracy of the position positioning mode control is ensured. This kind of mode of fixing a position through the cooperation of position detection piece 90 and encoder 50 has reduced the cost for adopting two encoders 50 to carry out the mode of speed and position double closed loop control on the one hand, and on the other hand is higher than the mode control accuracy of conventional multistage detection and control, also can adapt to higher transport efficiency demand to make production efficiency higher, reduced the fault rate moreover.

It should be understood that although the present description has been described in terms of various embodiments, not every embodiment includes only a single embodiment, and such description is for clarity purposes only, and those skilled in the art will recognize that the embodiments described herein may be combined as suitable to form other embodiments, as will be appreciated by those skilled in the art.

The above description is only an exemplary embodiment of the present disclosure, and is not intended to limit the scope of the present disclosure. Any person skilled in the art should be able to make equivalent changes, modifications and combinations without departing from the concept and principle of the embodiments of the present application.

Claims

1. A rolling machine is characterized by comprising a motor and a positioning control system, wherein the positioning control system is connected with the motor to control the motor to drive a conveying object to move and position, the positioning control system comprises a control unit, a position detection piece and an encoder, the control unit is respectively connected with the position detection piece and the encoder, the encoder is connected with the motor and detects the real-time position of the motor relative to the conveying object, the position detection piece is arranged on a moving path of the conveying object driven by the motor and sends a trigger signal to the control unit when the conveying object passes through;

the control unit is used for:

in the running process of the motor, if a trigger signal sent when the position detection piece is triggered is received, a passive zero returning action is executed, so that the real-time position detected by the encoder at the current moment is determined as a position zero point;

entering a position locating mode, and acquiring a target control speed and a locating distance corresponding to the position locating mode, wherein the locating distance is used for indicating the distance between a target locating position and the locating zero point;

and controlling the motor according to the positioning distance, the target control speed and the real-time position, relative to the positioning zero point, detected by the encoder so as to position the conveying object corresponding to the motor to the target positioning position.

2. The rolling machine of claim 1, wherein the positioning control system further comprises a programmable logic controller, the control unit comprises a frequency converter, the frequency converter is respectively connected to the motor, the encoder, the position detecting member and the programmable logic controller, and the frequency converter is further configured to:

sending a notification message to the connected programmable logic controller according to the trigger signal, wherein the notification message is used for indicating that the frequency converter is executing a passive zero returning action;

and acquiring a position positioning entering instruction sent by the programmable logic controller in response to the notification message, wherein the position positioning entering instruction is used for indicating to enter the position positioning mode and carries the target control speed and the positioning distance.

3. The rolling machine according to claim 2, wherein the notification message includes a status word for indicating monitoring positioning, and a set bit in the status word is used to indicate whether a passive zero-returning action is being performed.

4. The rolling machine according to claim 2, wherein the frequency converter comprises an IO terminal, the position detection member is connected with the IO terminal to input a signal to the IO terminal, the IO terminal is used for periodically sampling the input signal, and a time interval between two adjacent sampling periods is less than 1 millisecond.

5. The rolling machine according to claim 2, wherein the frequency converter is further configured to enter a speed control mode before a triggering signal sent when the position detecting member is triggered is received and a passive zero returning action is executed, the speed control mode carries set speed information corresponding to the motor, and the motor is controlled according to the set speed information so that the running speed of the motor matches the set speed information.

6. A positioning method of a rolling machine, which is applied to a positioning control system of the rolling machine for controlling a motor of the rolling machine, the positioning control system comprising a control unit, an encoder and a position detection member, the encoder being provided on the motor, the method being particularly applied to the control unit, the position detection member being used for detecting whether a conveying object driven by the motor passes through, the method comprising:

7. The method of claim 6, wherein entering into a position location mode and obtaining a target control speed and a location distance corresponding to the position location mode comprises:

sending a notification message, wherein the notification message is used for indicating that a passive zero returning action is being executed;

acquiring a position positioning entering instruction responding to the notification message;

and entering the position positioning mode according to the position positioning entering instruction, and acquiring a target control speed and a positioning distance corresponding to the position positioning mode from the position positioning entering instruction.

8. The method of claim 7, wherein the notification message includes a status word indicating the monitoring position, and a set bit in the status word is used to indicate whether a passive zero-returning action is being performed.

9. The method of claim 6, wherein before performing the passive zeroing action if the trigger signal sent when the position detector is triggered is received, the method further comprises:

entering a speed control mode, wherein the speed control mode carries set speed information, and the set speed information is used for indicating the running speed of the motor;

and controlling the motor according to the set speed information so as to enable the running speed of the motor to be matched with the set speed information.

10. The method of claim 6, wherein before performing the passive zeroing action if the trigger signal sent when the position detector is triggered is received, the method further comprises:

configuring an IO terminal to be connected with the position detection piece so as to receive a signal input by the position detection piece and periodically sample the input signal, wherein the time interval between two adjacent sampling periods of the IO terminal is less than 1 millisecond.