Electric flat carriage control system and control method thereof

Abstract

The invention provides an electric flat carriage control system and a control method thereof. An electric flat carriage running on a track is provided with a PLC, a photoelectric sensor and an RFID reader-writer, and a motor shaft of the electric flat carriage is provided with an encoder. RFID tags matched with the RFID reader-writer in a radio frequency communication mode and reflectors matched with the photoelectric sensors are arranged at the positioning points arranged on the track at intervals, after coordinates are input, the electric flat carriage accurately arrives at the coordinate points under the cooperation of the PLC, the photoelectric sensors and the RFID reader-writer, the electric flat carriage is stopped at the designated position through a preset PLC program when a fault occurs, and the electric flat carriage is prevented from being damaged. And troubleshooting and maintenance are facilitated.

Description

Technical Field

[0001] This invention relates to an electric flatbed cart control system and its control method. Background Technology

[0002] The slag slow cooling zone is a dedicated process area for handling high-temperature molten slag in copper smelting. Slag is transferred in this zone via an electric flatcar docking at the slag inlet. Currently, the electric flatcars in the slag slow cooling zone are generally positioned using encoders or proximity switches. When using encoders alone, the electric flatcar is prone to positioning errors due to varying wear conditions of the wheel sets. When using proximity switches alone, if the proximity switch malfunctions and causes positioning errors, the electric flatcar cannot run at the preset speed, affecting production. Therefore, the positioning scheme for the electric flatcar needs to be redesigned.

[0003] Titled "Contactless Power Supply Intelligent Heavy-Duty Mold Transfer Vehicle" (Document No. CN208963921U, hereinafter referred to as Document 1), this paper proposes a scheme that involves pre-embedding high-frequency cables, intermediate-frequency cables, magnetic nails, and communication cables along the vehicle's running path. The high-frequency cables, in conjunction with a power-collecting board, supply power to the vehicle. The intermediate-frequency cables, in conjunction with a guide antenna mounted on the vehicle, enable guidance. A magnetic nail reading device reads the magnetic nail signal and instantly records the position value of the encoder installed on the rotating rod 44 drive mechanism, thus enabling control of the vehicle. As can be seen from the positioning, Reference 1 mainly uses a magnetic nail reading device, pre-embedded magnetic nails, intermediate frequency cables, and guide antennas to improve the positioning and guidance of the transfer vehicle. However, the slag slow cooling area has harsh working conditions such as high temperature radiation, dust accumulation, heavy load crushing, and molten slag leakage. The pre-embedded cables are prone to failures such as cable insulation aging, short circuits, and signal attenuation. The pre-embedded magnetic nails are prone to problems such as magnetic attenuation, identification failure, and facility damage. In addition, the bottom of the transfer vehicle in Reference 1 is equipped with contactless power supply, which is more likely to be damaged in the slag slow cooling area. Therefore, the above solutions are difficult to implement in the slag slow cooling area.

[0004] Titled "Sorting Equipment and Control Method Thereof" (Document No. CN120504107A, hereinafter referred to as Document 2), it provides a scheme for positioning the transfer vehicle 14 by cooperating with a first sensor 1231, a first trigger 1241, a second sensor 142, a second trigger 143, a third sensor 1232, and a third trigger 1242. Document 2 uses the cooperation of the first sensor 1231 and the first trigger 1241 to determine whether the first support 1211 and the second support 1212 are aligned with the first track 111. The transport vehicle 14 determines whether it is in position based on the second sensor 142, and the first vertical transport machine 12 can determine whether the transport vehicle 14 is in position based on the third sensor 1232. It can be seen that the positioning of the transport vehicle 14 during the transport process is mainly achieved by multiple sensors and triggers in Reference 2. However, its drawbacks are that multiple sensors and triggers are prone to false triggering, the coding is complex, and the entire process will be interrupted if a sensor fails during the transport process. There are also no quick troubleshooting measures, the troubleshooting process is cumbersome and time-consuming, and the time required to restore the transport process is long. Summary of the Invention

[0005] The primary objective of this invention is to provide an electric flatbed cart control system.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An electric flatbed cart control system includes a PLC, photoelectric sensors, an RFID reader / writer, and an encoder mounted on the motor shaft of the electric flatbed cart running on a track. The digital input interface of the PLC is connected to the digital output interface of the RFID reader / writer via a serial port. The digital input interface of the PLC is electrically connected to the output terminal of the photoelectric sensor. The A, B, and Z phases of the encoder output terminal are respectively connected to the input terminal of the high-speed counter of the PLC. RFID tags that cooperate with the RFID reader / writer radio frequency communication and reflectors adapted to the photoelectric sensors are installed at positioning points arranged at intervals on the track. The positioning points have calibration coordinate values ​​corresponding to the real-time coordinate values ​​of the PLC.

[0008] Another object of the present invention is to provide a control method for an electric flatbed cart control system.

[0009] To achieve the above-mentioned objectives, the present invention employs the following steps:

[0010] S1. When the electric flatbed car stops at any positioning point, the preset target point A (Xa,Ya) is input into the PLC. The PLC generates the current real-time coordinate value (Xt,Yt) by using photoelectric sensors and RFID readers in conjunction with the light shield and RFID tag at the stopping positioning point.

[0011] S2. The PLC compares the real-time coordinate values (Xt, Yt) with the coordinate values of the preset target point A (Xa, Ya). When Xa > Xt and Ya > Yt, the PLC controls the electric flat car to move forward in the X and Y axis directions of the track. When Xa < Xt and Ya < Yt, the PLC controls the electric flat car to move backward in the X and Y axis directions of the track. During the operation of the electric flat car, the encoder outputs operation data, enabling the PLC to update the real-time coordinate values (Xt, Yt).

[0012] S3. When the electric flat car runs to a position close to the preset target point A, the RFID reader of the electric flat car detects the RFID tag of the preset target point A. After receiving the signal feedback from the RFID reader, the PLC continues to drive.

[0013] When the electric flat car runs close to the preset target point A, based on the relevant parameters received by the PLC from the photoelectric sensor, the following controls are made:

[0014] S41. When the electric flat car runs within the signal continuous travel range near the preset target point A, the PLC receives the continuous feedback signal transmitted by the photoelectric sensor through the reflector. Within this signal continuous travel range, when the real-time coordinate values (Xt, Yt) of the PLC are (Xa, Ya), the PLC controls the electric flat car to stop moving forward. At this time, the electric flat car stops at the preset target point A.

[0015] S42. In step S3, when the real-time coordinate values (Xt, Yt) of the PLC are close to the coordinate values (Xa, Ya) of point A, but the PLC does not read the RFID tag signal at point A feedback from the RFID reader, the PLC controls the electric flat car to move forward in the original direction. When the real-time coordinate values (Xt, Yt) of the PLC are (Xa, Ya) and the PLC receives the continuous feedback signal transmitted by the photoelectric sensor through the reflector, the PLC controls the electric flat car to stop and issues an RFID fault alarm prompt in the PLC.

[0016] S43. In step S3, the RFID reader detects the RFID tag at point A, but the PLC does not receive the feedback signal of the photoelectric sensor for the reflector at point A within the signal continuous travel range near the target point A. When the difference between the real-time coordinate values (Xt, Yt) and (Xa, Ya) of the PLC reaches the threshold of 1500, that is, when |Xt - Xa| > 1500 and |Yt - Ya| > 1500, the PLC controls the electric flat car to stop and issues a photoelectric sensor fault alarm prompt in the PLC.

[0017] S5. In any step S1 to S4, when the PLC passes any positioning point B (Xb, Yb) in the travel path, the PLC reads the RFID tag signal at point B fed back by the RFID reader. The PLC controls the electric flatcar to continue moving towards point B (Xb, Yb). The PLC receives the continuous feedback signal transmitted by the photoelectric sensor through the reflector. At this time, if the real-time coordinate values ​​(Xt, Yt) and (Xb, Yb) of the PLC satisfy |Xt-Xb|>1500 and |Yt-Yb|>1500, the PLC controls the electric flatcar to stop and issues an encoder fault alarm in the PLC.

[0018] In the above scheme, after the coordinates are input, the electric flatbed cart accurately arrives at the coordinate point with the cooperation of PLC, photoelectric sensor, and RFID reader. In case of failure, the electric flatbed cart is stopped at the designated position by the preset PLC program. At the same time, the PLC issues an alarm prompt for the component failure, which facilitates fault diagnosis and maintenance. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the operation of the electric flatbed cart of the present invention;

[0020] Figure 2 This is a logic flowchart of steps S1 to S41 of the present invention;

[0021] Figure 3 This is a logic flowchart of steps S42 and S43 of the present invention;

[0022] Figure 4 This is a logic flowchart of step S5 of the present invention;

[0023] Figure 5 For the present invention Figure 1 A magnified view of a portion of the image. Detailed Implementation

[0024] Combination Figure 1 , 5 The electric flatcar control system shown includes an electric flatcar 20 running on track 10 equipped with a PLC 21, a photoelectric sensor 23, an RFID reader / writer 22, and an encoder 24 mounted on the motor shaft of the electric flatcar 20. The digital input interface of the PLC 21 is connected to the digital output interface of the RFID reader / writer 22 via a serial port, and the digital input interface of the PLC 21 is electrically connected to the output terminal of the photoelectric sensor 23. The A, B, and Z phases of the encoder 24 output terminal are respectively connected to the high-speed counter input terminal of the PLC 21. At the positioning points 30 spaced apart on track 10, there are RFID tags 11 that cooperate with the RFID reader / writer 22 for radio frequency communication and reflectors 12 that are adapted to the photoelectric sensor 23. The positioning points 30 have calibration coordinate values ​​corresponding to the real-time coordinate values ​​of the PLC 21.

[0025] In the above scheme, PLC21 is the operation controller of electric flatbed cart 20. It determines the current coordinates and direction of electric flatbed cart 20 based on the data transmitted by photoelectric sensor 23, RFID reader 22 and encoder 24 installed on the motor shaft of electric flatbed cart 20. When electric flatbed cart 20 is running, the motor shaft inside electric flatbed cart 20 is always rotating. The encoder 24 installed on the motor shaft generates the running data of electric flatbed cart 20 according to the rotation direction and number of revolutions of the motor shaft. The PLC21 processes the data to obtain the real-time coordinate value of electric flatbed cart. RFID reader 22 obtains feedback signal from RFID tag 11 at positioning point 30 on track 10 through radio frequency communication. The feedback signal transmitted by RFID reader 22 to PLC21 helps PLC21 determine which positioning point 30 it has passed. Reflector 12 can provide continuous feedback signal to photoelectric sensor 23 to help PLC21 accurately reach positioning point 30. It should be noted that the duration of this feedback signal is determined by the length of reflector 12. PLC21 generates real-time coordinate values ​​through encoder 24. When it reaches positioning point 30, it verifies the real-time coordinate values ​​of electric flatcar 20 through photoelectric sensor 23, RFID reader 22, light shield 12 on the track, and RFID tag 11. Each time it passes positioning point 30, it performs a logical judgment on the running data of electric flatcar 20, so that the electric flatcar 20 can promptly detect data abnormalities during operation. There are corresponding solutions for individual faults of photoelectric sensor 23, RFID reader 22, and encoder 24 (solutions are described below), which ensures the efficiency of fault diagnosis and maintenance and reduces the time required to restore the electric flatcar 20 to operation. The track 10, electric flatcar 20 and their on-board components are all commonly used equipment in slag slow cooling areas and are suitable for slag slow cooling areas.

[0026] Combination Figure 1 , 5 The track 10 shown is laid along the X and Y axes. The calibration coordinate values ​​are determined by the X and Y axis coordinates. The positioning point 30 includes the calibration positioning point. When the electric flatcar 20 passes the calibration positioning point, if the RFID reader 22 reads the RFID tag 11 of the calibration positioning point and the PLC 21 receives the signal from the reflector 12 of the calibration positioning point transmitted by the photoelectric sensor 23, the PLC 21 updates the real-time coordinate value to the calibration coordinate value at the calibration positioning point.

[0027] In the above solution, the track 10 is laid along the X and Y axes for facilitating the setting of the calibrated coordinate values. The calibrated coordinate values of the positioning points are determined by the electric flat car 20 with an initial coordinate value of (0, 0) running along the X and Y axes to the positioning points multiple times, and the PLC 21 combines the average value of the number of pulse signals transmitted multiple times by the encoder 24. When the electric flat car 20 passes through the calibration positioning point, the setting of the calibration positioning point can eliminate the cumulative error generated by the encoder 24 on the electric flat car 20, and update the real-time coordinate value on the PLC 21 to the calibrated coordinate value at the calibration positioning point, thereby improving the accuracy of the real-time coordinate value on the PLC 21.

[0028] Combined with Figure 1 、 2 The control method of the electric flat car control system shown in 3, 4, and 5 includes the following steps, as follows:

[0029] S1. When the electric flat car 20 stops at any positioning point 30, input the preset target point A (Xa, Ya) into the PLC 21. The PLC 21 generates the current real-time coordinate value (Xt, Yt) of the PLC 21 by cooperating with the light-shielding plate 12 and the RFID tag 11 at the position of the stopped positioning point 30 through the photoelectric sensor 23 and the RFID reader 22 respectively;

[0030] S2. The PLC 21 compares the real-time coordinate value (Xt, Yt) with the coordinate value (Xa, Ya) of the preset target point A. When Xa > Xt and Ya > Yt, control the electric flat car 20 to move forward in the X and Y axis directions of the track 10 through the PLC 21. When Xa < Xt and Ya < Yt, control the electric flat car 20 to move backward in the X axis and Y axis directions of the track 10 through the PLC 21. During the operation of the electric flat car 20, the encoder 24 outputs operation data, enabling the PLC 21 to update the real-time coordinate value (Xt, Yt);

[0031] S3. When the electric flat car 20 runs to a position close to the preset target point A, the RFID reader 22 of the electric flat car 20 detects the RFID tag 11 of the preset target point A. After the PLC 21 receives the signal fed back by the RFID reader 22, it continues to drive;

[0032] When the electric flat car 20 runs to a position close to the preset target point A, based on the relevant parameters received by the PLC 21 from the photoelectric sensor 23, make the following controls:

[0033] S41. When the electric flat car 20 runs within the signal continuous travel range near the preset target point A, the PLC 21 receives the continuous feedback signal transmitted by the photoelectric sensor 23 through the reflector 12. Within the signal continuous travel range, when the real-time coordinate value (Xt, Yt) of the PLC 21 is (Xa, Ya), the PLC 21 controls the electric flat car 20 to stop moving forward. At this time, the electric flat car 20 stops at the preset target point A;

[0034] S42. In step S3, the real-time coordinate value (Xt, Yt) of PLC21 is close to the coordinate value (Xa, Ya) of point A. However, PLC21 does not read the RFID tag 11 signal at point A fed back by RFID reader 22. PLC21 controls the electric flatbed cart 20 to move forward in the original direction. When the real-time coordinate value (Xt, Yt) of PLC21 is (Xa, Ya) and PLC21 receives a continuous feedback signal from photoelectric sensor 23 transmitted through reflector 12, PLC21 controls the electric flatbed cart 20 to stop and issues an RFID fault alarm in PLC21.

[0035] S43. In step S3, the RFID reader 22 detects the RFID tag 11 at point A, but the PLC 21 does not receive the feedback signal from the photoelectric sensor 23 to the reflector 12 at point A within the signal continuous travel range near the target point A. When the difference between the real-time coordinate values ​​(Xt, Yt) and (Xa, Ya) of the PLC 21 reaches the threshold of 1500, that is, when |Xt-Xa|>1500 and |Yt-Ya|>1500, the PLC 21 controls the electric flatbed cart 20 to stop and issues a fault alarm prompt for the photoelectric sensor 23 in the PLC 21.

[0036] S5. In any step S1 to S4, when PLC21 passes any positioning point B (Xb, Yb) in the travel path, PLC21 reads the RFID tag 11 signal at point B fed back by RFID reader 22. PLC21 controls electric flatbed cart 20 to continue moving towards point B (Xb, Yb). PLC21 receives the continuous feedback signal transmitted by photoelectric sensor 23 through reflector 12 at point B. At this time, if the real-time coordinate values ​​(Xt, Yt) and (Xb, Yb) of PLC21 satisfy |Xt-Xb|>1500 and |Yt-Yb|>1500, PLC21 controls electric flatbed cart 20 to stop and issues encoder 24 fault alarm prompt in PLC21.

[0037] In the above scheme, steps S1 to S41 describe the process of the electric flatbed cart 20 moving to the preset target point A, which will not be repeated here. This process enables the electric flatbed cart 20 to accurately reach point A under the control of PLC 21. Steps S42 to S5 respectively preset handling schemes for RFID faults, photoelectric sensor 23 faults, and encoder 24 faults during the operation of the electric flatbed cart 20, ensuring that the electric flatbed cart 20 stops at the preset corresponding position after a fault. This facilitates maintenance personnel in quickly locating the electric flatbed cart 20 and the faulty component, reducing the time required to restore the electric flatbed cart 20 to operation. It should be noted that the aforementioned coordinate difference threshold of 1500 represents the coordinate change in the X and Y directions formed by 1500 pulse signals emitted by the encoder 24 in a single direction, with a straight-line distance of approximately 1.5 meters. The coordinate difference threshold can be adjusted according to the site and requirements.

Claims

1. An electric flatbed cart control system, characterized in that: An electric flat car (20) running on a track (10) is provided with a PLC (21), a photoelectric sensor (23), an RFID reader / writer (22), and an encoder (24) is provided on the motor shaft of the electric flat car (20). The digital input interface of the PLC (21) is connected to the digital output interface of the RFID reader / writer (22) through a serial port. The digital input interface of the PLC (21) is electrically connected to the output end of the photoelectric sensor (23). The output ends A, B, and Z phases of the encoder (24) are respectively connected to the high-speed counter input ends of the PLC (21). RFID tags (11) that communicate with the RFID reader / writer (22) by radio frequency and reflectors (12) adapted to the photoelectric sensor (23) are provided at the positioning points (30) arranged at intervals on the track (10). The positioning points (30) have calibration coordinate values corresponding to the real-time coordinate values of the PLC (21).

2. The electric flatbed cart control system according to claim 1, characterized in that: The track (10) is laid along the X and Y axes, and the calibration coordinate values are determined by the X and Y axis coordinates.

3. The electric flatbed cart control system according to claim 1 or 2, characterized in that: The positioning points (30) include calibration positioning points. When the electric flat car (20) passes through the calibration positioning points, if the RFID reader / writer (22) reads the RFID tag (11) of the calibration positioning point and the PLC (21) receives the signal of the reflector (12) of the calibration positioning point transmitted by the photoelectric sensor (23), the PLC (21) updates the real-time coordinate values to the calibration coordinate values at the calibration positioning points.

4. A control method for an electric flatbed cart control system as described in claim 1, 2, or 3, characterized in that... ​ ​ ​ ​ ​ S41. When the electric flatbed cart (20) runs within the signal continuous travel range near the preset target point A, the PLC (21) receives the continuous feedback signal transmitted from the photoelectric sensor (23) through the reflector (12). Within the signal continuous travel range, when the real-time coordinate value (Xt,Yt) of the PLC (21) is (Xa,Ya), the PLC (21) controls the electric flatbed cart (20) to stop moving forward. At this time, the electric flatbed cart (20) stops at the preset target point A. S42. In step S3, the real-time coordinate value (Xt,Yt) of PLC (21) is close to the coordinate value (Xa,Ya) of point A. However, PLC (21) does not read the RFID tag (11) signal at point A fed back by RFID reader (22). PLC (21) controls electric flatbed cart (20) to move forward in the original direction. When the real-time coordinate value (Xt,Yt) of PLC (21) is (Xa,Ya) and PLC (21) receives the continuous feedback signal transmitted from photoelectric sensor (23) through reflector (12), PLC (21) controls electric flatbed cart (20) to stop and issues an RFID fault alarm in PLC (21). S43. In step S3, the RFID reader (22) detects the RFID tag (11) at point A. However, the PLC (21) does not receive the feedback signal from the photoelectric sensor (23) to the reflector (12) at point A within the signal continuous travel range near the target point A. When the difference between the real-time coordinate values ​​(Xt,Yt) and (Xa,Ya) of the PLC (21) reaches the threshold of 1500, that is, when |Xt-Xa|>1500 and |Yt-Ya|>1500, the PLC (21) controls the electric flatbed cart (20) to stop and issues a fault alarm prompt for the photoelectric sensor (23) in the PLC (21). S5. In any step S1 to S4, when PLC (21) passes any positioning point B (Xb,Yb) in the travel path, PLC (21) reads the RFID tag (11) signal at point B fed back by RFID reader (22). PLC (21) controls electric flatbed cart (20) to continue moving towards point B (Xb,Yb). PLC (21) receives the continuous feedback signal transmitted by photoelectric sensor (23) through reflector (12) at point B. If the real-time coordinate values ​​(Xt,Yt) and (Xb,Yb) of PLC (21) satisfy |Xt-Xb|>1500 and |Yt-Yb|>1500, PLC (21) controls electric flatbed cart (20) to stop and issues encoder (24) fault alarm prompt in PLC (21).

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