A reference radiation field guide rail positioning automatic control system and method based on a PLC

Abstract

The present application relates to a kind of reference radiation field guide rail positioning automatic control system based on PLC, comprising: trolley translation drive component, trolley transverse drive component, trolley lifting drive component, trolley rotation drive component and circuit box and control module, trolley translation drive component is used to drive trolley movement and positioning, trolley transverse drive component is used to drive trolley transverse movement and positioning, trolley lifting drive component is used to drive trolley lifting and positioning, trolley rotation drive component is used to drive trolley rotation and positioning, circuit box is set on trolley, control module is located in the circuit box.The present application also includes a kind of reference radiation field guide rail positioning automatic control method based on PLC, based on the mutual conversion of PLC algorithm can be realized in reference radiation field air specific energy release rate and distance;Also according to the experimental procedure that user inputs in host computer interface, control trolley automatically runs to set position and carries out irradiation operation, improve the degree of automation of trolley device.

Description

Technical Field

[0001] This invention belongs to the field of reference radiation field construction technology, specifically relating to a PLC-based automatic control system and method for reference radiation field guide rail positioning. Background Technology

[0002] With the rapid development of nuclear technology in various fields such as industry, medicine, agriculture, environmental protection, and public safety in my country, radiation monitoring has attracted increasing attention, and various radiation monitoring instruments have emerged. To ensure the accuracy of the measurements taken by monitoring instruments, it is necessary to establish a corresponding reference radiation field and transfer the measurement values ​​through calibration. This provides a basis for analyzing, judging, and controlling dose levels, thereby effectively ensuring the safety of workers engaged in radiation work.

[0003] In the instrument calibration process, different air kerma rates are obtained by changing the distance between the instrument and the radiation source. Therefore, it is necessary to establish a precise multi-degree-of-freedom guide rail positioning system. In recent years, with the increasing automation of reference radiation field equipment, guide rail positioning systems based on stepper motors can realize remote control of the guide rail. However, the motion control system still has the following problems: (1) The control circuit is generally placed in a separate control cabinet, which has low integration. Later modifications require the control cabinet to be remade, resulting in insufficient reproducibility; (2) The wiring between the control cabinet and the equipment in the laboratory is complicated, making equipment maintenance difficult; (3) The positioning accuracy is relatively low, and there is a step loss phenomenon; (4) When the motor fails, it often does not have an alarm function, requiring experimental personnel to judge whether the motor is faulty and the type of fault based on experience, which creates a certain risk; (5) The degree of automation is low. Although it can be remotely controlled, operators still need to perform necessary calculations and repetitive operations. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a PLC-based automatic control system and method for guide rail positioning based on a reference radiation field, so as to achieve a guide rail positioning system control scheme with high precision, mechatronics integration, strong replicability, and a high degree of intelligence and automation.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a PLC-based automatic control system for reference radiation field guide rail positioning, comprising: a trolley translation drive assembly, a trolley lateral movement drive assembly, a trolley lifting drive assembly, a trolley rotation drive assembly, a circuit box, and a control module. The trolley translation drive assembly is used to drive the trolley to move and position horizontally; the trolley lateral movement drive assembly is used to drive the trolley to move laterally and position horizontally; the trolley lifting drive assembly is used to drive the trolley to lift and position vertically; and the trolley rotation drive assembly is used to drive the trolley to rotate and position. The circuit box is mounted on the trolley, and the control module is located inside the circuit box and is used to control the trolley translation drive assembly, the trolley lateral movement drive assembly, the trolley lifting drive assembly, and the trolley rotation drive assembly.

[0006] Furthermore, the control module includes a horizontal movement servo driver, a horizontal traverse servo driver, a vertical lift servo driver, a horizontal rotation servo driver, an air switch, a first switching power supply, a second switching power supply, DC power distribution terminals, a PLC, a main power terminal, a grounding terminal, a neutral terminal, a first external power supply terminal, a second external power supply terminal, PLC digital input terminals, and PLC digital output terminals. The PLC includes a CPU module, a Modbus communication module, and a digital input module. The external power supply line enters the control circuit through the main power terminal; the live wire enters different electrical devices through the air switch; the neutral wire enters different devices through the neutral terminal; and the ground wire enters different electrical devices through the grounding terminal. The horizontal movement servo driver, horizontal traverse servo driver, vertical lift servo driver, and horizontal rotation servo driver... The actuators control the four degrees of freedom of the trolley and communicate with the PLC via pulse commands. The first switching power supply powers the PLC via the DC power distribution terminal and the photoelectric switches on the trolley via the first external power supply terminal. The second switching power supply powers the miniature cameras on the trolley via the second external power supply terminal. The CPU module processes the acquired signals according to the written program and outputs the signals to each servo driver via the PLC digital output terminal. The CPU module includes a network interface for remote connection between the PLC and the host computer interface. The Modbus communication module is connected to the communication port of the servo driver for querying driver alarm parameters. The digital input module can acquire external sensor signals and transmit them to the CPU module. The external sensor signals enter the PLC via the PLC digital input terminal.

[0007] Furthermore, the PLC-based reference radiation field guide rail positioning automatic control system includes a horizontal movement servo motor, a horizontal movement reducer, a horizontal lower limit switch, a horizontal upper limit switch, a horizontal origin switch, and a horizontal movement camera; wherein, the horizontal movement servo motor and the horizontal movement reducer drive the belt to rotate, and the horizontal lower limit switch, the horizontal upper limit switch, the horizontal origin switch, and the horizontal movement camera are used to realize the positioning of the trolley's horizontal movement.

[0008] Furthermore, the PLC-based reference radiation field guide rail positioning automatic control system includes a horizontal traverse servo motor, a horizontal lower limit switch, a horizontal upper limit switch, a horizontal origin switch, and a horizontal traverse camera; wherein, the horizontal traverse servo motor is used to drive the trolley to move horizontally, and the horizontal lower limit switch, the horizontal upper limit switch, the horizontal origin switch, and the horizontal traverse camera are used to realize the positioning of the trolley's horizontal traverse movement.

[0009] Furthermore, the PLC-based reference radiation field guide rail positioning automatic control system includes a vertical lifting servo motor, a vertical lower limit switch, a vertical upper limit switch, and a vertical origin switch; wherein, the vertical lifting servo motor is used to drive the lifting and lowering of the trolley, and the vertical lower limit switch, the vertical upper limit switch, and the vertical origin switch are used to realize the positioning of the trolley lifting and lowering.

[0010] Furthermore, the PLC-based reference radiation field guide rail positioning automatic control system includes a horizontal rotation servo motor, a horizontal circumferential origin switch, and a horizontal rotation camera; wherein, the horizontal rotation servo motor is used to drive the trolley to rotate horizontally, and the horizontal circumferential origin switch and the horizontal rotation camera are used to realize the positioning of the trolley's horizontal rotation.

[0011] Furthermore, the PLC-based reference radiation field guide rail positioning automatic control system also includes a remote control handle, which is connected to the PLC input terminal and is used to control the vehicle to move forward and backward horizontally; move left and right horizontally; move up and down vertically; and rotate clockwise and counterclockwise horizontally.

[0012] Furthermore, the PLC-based automatic control system for positioning the reference radiation field guide rail also includes a laser calibrator, which emits horizontal and vertical cross laser lines that are aligned with the position of the radiation source to determine the irradiation position.

[0013] This invention also provides a PLC-based automatic control method for positioning a reference radiation field guide rail, comprising the following steps:

[0014] S1, Design the experimental process on the host computer interface and input the PLC variables involved in the experimental process;

[0015] S2, the PLC reads the experimental process variables, converts the target air kerma rate into the target distance, and sends the corresponding number of pulse commands to the horizontal movement servo driver. After the horizontal movement servo motor rotates to the position, it sends feedback to the PLC.

[0016] S3, after moving horizontally into position, control the horizontal turntable to rotate to the first angle, and after the horizontal rotation servo motor rotates to the position, send feedback to the PLC;

[0017] S4, after the horizontal turntable rotates to the correct position, irradiation begins. The time accumulator inside the PLC starts and ends after the preset time is reached.

[0018] S5, read the next turntable angle, repeat steps S3 and S4 until the experimental repetition number is reached.

[0019] Furthermore, the conversion of the target air kerma rate into target distance specifically involves:

[0020] Select N reference points in the reference radiation field and obtain the distance of each reference point from the radiation source and the air kerma rate at the corresponding reference point;

[0021] The collected data is processed and fitted.

[0022] The target dose rate was substituted into the fitted curve to obtain the corresponding distance.

[0023] The advantages of this invention are as follows: The control module is mounted on the trolley device, achieving an integrated electromechanical design between the control module and the trolley device. Therefore, most signals can be processed locally, and most equipment can be powered locally, greatly reducing wiring between the trolley device and the control room in the laboratory and effectively improving system integration. Furthermore, a fault information transmission channel and fault handling scheme are set up between the PLC and the servo motor, effectively ensuring the safe and stable operation of the device. Using the servo motor as the actuator forms a closed-loop control of the position parameters, ensuring positioning accuracy. Simultaneously, by fitting and calculating the data collected by the PLC, trolley positioning at any air kerma rate in the reference radiation field is achieved, improving the device's intelligence to a certain extent. Based on the experimental procedure input by the user on the host computer interface, the PLC controls the trolley to automatically move to the set position and perform the irradiation operation, improving the automation level of the trolley device and reducing repetitive labor for experimental personnel. Attached Figure Description

[0024] Figure 1 This is a main view of the distribution of electrical components of a guide rail trolley in a PLC-based automatic control system for reference radiation field guide rail positioning.

[0025] Figure 2 This is a side view of the distribution of electrical components on a guide rail trolley in a PLC-based automatic control system for reference radiation field guide rail positioning.

[0026] Figure 3 This is a schematic diagram of the overall structure of the control circuit of the guide rail positioning system;

[0027] Figure 4 This is the signal flow diagram of the control circuit of the guide rail positioning system;

[0028] Figure 5 This is a schematic diagram of the control circuit of the guide rail positioning system;

[0029] Figure 6 This is a flowchart of a PLC algorithm for fitting air kerma rate to a distance function;

[0030] Figure 7 This is a PLC algorithm flowchart for converting air kerma rate to distance;

[0031] Figure 8 This is a flowchart of the PLC algorithm for automatic trolley operation;

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Horizontal movement servo motor; 2. Horizontal movement reducer; 3. Lower limit switch in the horizontal direction; 4. Upper limit switch in the horizontal direction; 5. Horizontal origin switch; 6. Horizontal movement camera; 7. Vertical lifting servo motor; 8. Lower limit switch in the vertical direction; 9. Upper limit switch in the vertical direction; 10. Vertical origin switch; 11. Horizontal rotation servo motor; 12. Horizontal circumferential origin switch; 13. Horizontal rotation camera; 14. Horizontal transverse movement servo motor; 15. Lower limit switch in the horizontal direction; 16. Upper limit switch in the horizontal direction; 17. Horizontal transverse origin switch; 18. Horizontal transverse movement camera; 19. 20. Control circuit box; 21. Laser calibrator; 22. Remote control handle; 23. Horizontal movement servo driver; 24. Horizontal transverse movement servo driver; 25. Vertical lifting servo driver; 26. Horizontal rotation servo driver; 27. Air switch; 28. First switching power supply; 29. ​​Second switching power supply; 30. DC power distribution terminal; 31. PLC; 32. Main power terminal; 33. Grounding terminal; 34. Neutral terminal; 35. Socket; 36. First external power supply terminal; 37. Second external power supply terminal; 38. PLC digital input terminal; 39. PLC digital output terminal; 30. Cable tray. Detailed Implementation

[0034] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0035] like Figure 1-5 As shown, this invention proposes a PLC-based automatic control system for reference radiation field guide rail positioning, which includes: a trolley translation drive assembly, a trolley lateral movement drive assembly, a trolley lifting drive assembly, a trolley rotation drive assembly, a circuit box 19, and a control module. The trolley translation drive assembly is used to drive the trolley to move and position horizontally, the trolley lateral movement drive assembly is used to drive the trolley to move laterally and position horizontally, the trolley lifting drive assembly is used to drive the trolley to lift and position vertically, and the trolley rotation drive assembly is used to drive the trolley to rotate and position. The circuit box 19 is mounted on the trolley, and the control module is located inside the circuit box 19 and is used to control the trolley translation drive assembly, the trolley lateral movement drive assembly, the trolley lifting drive assembly, and the trolley rotation drive assembly.

[0036] Furthermore, the control module includes a horizontal movement servo driver 22, a horizontal traverse servo driver 23, a vertical lifting servo driver 24, a horizontal rotation servo driver 25, an air switch 26, a first switching power supply 27, a second switching power supply 28, a DC power distribution terminal 29, a PLC 30, a main power terminal 31, a grounding terminal 32, a neutral terminal 33, a first external power supply terminal 35, a second external power supply terminal 36, a PLC digital input terminal 37, and a PLC digital output terminal 38. The PLC 30 includes a CPU module, a Modbus communication module, and a digital input module.

[0037] The external power supply line enters the control circuit through the main power terminal 31. The live wire enters different electrical devices through the air switch 26, the neutral wire enters different devices through the neutral terminal 33, and the ground wire enters different electrical devices through the grounding terminal 32. The horizontal movement servo driver 22, the horizontal transverse movement servo driver 23, the vertical lifting servo driver 24, and the horizontal rotation servo driver 25 control the four degrees of freedom of the carriage, and communicate with the PLC using pulse commands. The first switching power supply 27 supplies power to the PLC 30 through the DC power distribution terminal 29, and simultaneously supplies power to the various lights on the carriage through the first external power supply terminal 35. The electric switch provides power, and the second switching power supply 28 supplies power to each miniature camera on the trolley via the second external power supply terminal 36. The CPU module processes the acquired signals according to the written program and outputs signals to each servo drive via the PLC digital output terminal 38. The CPU module includes a network interface for remote connection between the PLC and the host computer interface. The Modbus communication module is connected to the communication port of the servo drive for querying drive alarm parameters. The digital input module can acquire external sensor signals and transmit them to the CPU module. The external sensor signals enter the PLC via the PLC digital input terminal 37.

[0038] It is understandable that the servo drive and the PLC use pulse commands to exchange information. In addition, to avoid external high-frequency interference, the signal between the drive and the PLC is transmitted using a shielded cable.

[0039] Furthermore, the PLC-based reference radiation field guide rail positioning automatic control system includes a horizontal movement servo motor 1, a horizontal movement reducer 2, a horizontal lower limit switch 3, a horizontal upper limit switch 4, a horizontal origin switch 5, and a horizontal movement camera 6; wherein, the horizontal movement servo motor 1 and the horizontal movement reducer 2 drive the belt to rotate, and the horizontal lower limit switch 3, the horizontal upper limit switch 4, the horizontal origin switch 5, and the horizontal movement camera 6 are used to realize the horizontal movement positioning of the trolley.

[0040] It is understandable that the existence of the reducer ensures that the motor has sufficient torque to drive the main structure of the trolley.

[0041] Furthermore, the PLC-based reference radiation field guide rail positioning automatic control system includes a horizontal traverse servo motor 14, a horizontal lower limit switch 15, a horizontal upper limit switch 16, a horizontal origin switch 17, and a horizontal traverse camera 18; wherein, the horizontal traverse servo motor 14 is used to drive the trolley to move horizontally, and the horizontal lower limit switch 15, the horizontal upper limit switch 16, the horizontal origin switch 17, and the horizontal traverse camera 18 are used to realize the positioning of the trolley's horizontal traverse movement.

[0042] Furthermore, the PLC-based reference radiation field guide rail positioning automatic control system includes a vertical lifting servo motor 7, a vertical lower limit switch 8, a vertical upper limit switch 9, and a vertical origin switch 10; wherein, the vertical lifting servo motor 7 is used to drive the lifting and lowering of the trolley, and the vertical lower limit switch 8, the vertical upper limit switch 9, and the vertical origin switch 10 are used to realize the positioning of the trolley lifting and lowering.

[0043] Furthermore, the PLC-based reference radiation field guide rail positioning automatic control system includes a horizontal rotation servo motor 11, a horizontal circumferential origin switch 12, and a horizontal rotation camera 13; wherein, the horizontal rotation servo motor 11 is used to drive the trolley to rotate horizontally, and the horizontal circumferential origin switch 12 and the horizontal rotation camera 13 are used to realize the positioning of the trolley's horizontal rotation.

[0044] It is understandable that the upper and lower limit switches for each degree of freedom are photoelectric switches, installed at both ends of the guide rails in each direction. When the trolley moves to the limit position, the photoelectric switch outputs a signal to the PLC30, and the PLC30 stops outputting movement commands to the servo driver, thus ensuring that the trolley moves within a safe and controllable range. The origin switches for each degree of freedom are also photoelectric switches, providing the trolley with physical origin information to ensure that the actual position matches the PLC output position. The cameras for each degree of freedom are all miniature cameras, installed above the scale, used to observe the actual running position of the trolley.

[0045] Furthermore, the PLC-based reference radiation field guide rail positioning automatic control system also includes a remote control handle 21, which is connected to the input terminal of the PLC 30 and is used to control the vehicle to move forward and backward in the horizontal direction; move left and right in the horizontal direction; move up and down in the vertical direction; and rotate clockwise and counterclockwise in the horizontal direction.

[0046] Furthermore, the PLC-based automatic control system for positioning the reference radiation field guide rail also includes a laser calibrator 20, which emits horizontal and vertical cross laser lines that are aligned with the position of the radiation source to determine the irradiation position.

[0047] In this control system, the PLC acts as the controller, with four input sources: the host computer interface, the remote control handle 21, field sensors, and the servo driver. The host computer interface communicates with the PLC via Ethernet protocol, enabling remote positioning of the trolley across multiple degrees of freedom. The remote control handle 21 transmits data to the PLC via a digital input module and includes forward and backward jog buttons for each degree of freedom. The field sensors transmit data to the PLC via the digital input module, effectively ensuring the safe and stable operation of the trolley device. The servo driver communicates with the PLC via Modbus protocol, sending servo motor alarm signals and fault types to the PLC, effectively protecting the motor and the trolley's mechanical structure.

[0048] In this control system, the PLC acts as the controller, and its outputs include: four-degree-of-freedom servo drives and a host computer interface. Based on the programmed sequence, the PLC converts the target position information into signal pulses and direction pulses, which are then output to each servo drive. As the servo motors rotate, their encoders feed back the operating information to the servo drives, thus forming a closed-loop position control system and ensuring precise positioning of the trolley. Upon receiving motion position feedback and fault alarm information from the servo drives, the PLC sends the data to the host computer interface, allowing researchers to intuitively understand the equipment's operating status.

[0049] Furthermore, the control module is also equipped with a cable tray 39.

[0050] Furthermore, the control module also includes a three-hole socket 34, which can power the main unit of the detection instrument on the trolley platform when needed.

[0051] like Figure 6-8 As shown, the present invention also provides a PLC-based automatic control method for positioning a reference radiation field guide rail, comprising the following steps:

[0052] S1, Design the experimental process on the host computer interface and input the PLC variables involved in the experimental process;

[0053] Specifically, the user designs the experimental procedure on the host computer interface and inputs the PLC variables involved in the experimental procedure: the number of experimental repetitions M, the target air kerma rate K. x Turntable angle θ j Irradiation time T j (j=1,2,…,M), the above parameter settings will be saved to the industrial computer and do not need to be set again.

[0054] S2, the PLC reads the experimental process variables, converts the target air kerma rate into the target distance, and sends the corresponding number of pulse commands to the horizontal movement servo driver. After the horizontal movement servo motor rotates to the position, it sends feedback to the PLC.

[0055] Specifically, the PLC reads the experimental process variables and sets the target air kerma rate K. x Convert to target distance R x Then, the PLC sends a corresponding number of pulse commands to the horizontal motion servo driver, and after the horizontal motion servo motor rotates to the correct position, it sends feedback back to the PLC.

[0056] S3, after moving horizontally into position, control the horizontal turntable to rotate to the first angle, and after the horizontal rotation servo motor rotates to the position, send feedback to the PLC;

[0057] Specifically, after the horizontal movement is completed, the horizontal turntable is controlled to move to the j-th target angle θ. j The PLC sends a corresponding number of pulse commands to the horizontal rotary servo driver, and the horizontal rotary servo motor sends feedback to the PLC after rotating into position.

[0058] S4, after the horizontal turntable rotates to the correct position, irradiation begins. The time accumulator inside the PLC starts and ends after the preset time is reached.

[0059] Specifically, after the horizontal turntable rotates to its position, the PLC sends a command to the host computer interface, and irradiation begins. The PLC's internal time accumulator starts, and when the running time reaches the preset time T... j Then, the irradiation was stopped.

[0060] S5, read the next turntable angle, repeat steps S3 and S4 until the experimental repetition number is reached;

[0061] Specifically, the PLC reads the next turntable angle θ. j+1 Repeat steps S3 and S4 until the number of repetitions reaches M times, at which point the automatic operation process ends and each degree of freedom of the trolley returns to its origin.

[0062] For a point-source radiation source, gamma photons are emitted uniformly in all directions. If the total number of gamma photons emitted per unit time is N0, then N0 gamma photons will pass through a sphere with radius R centered at the point source per unit time. Therefore, the number I of gamma photons passing through a unit area per unit time at a distance R from the point source can be expressed as:

[0063]

[0064] At this point, the radioactivity It can be considered a constant, therefore That is, the intensity of the radiation at the measurement point is inversely proportional to the square of the distance from the radiation source to the measurement point. Taking the logarithm of both sides of equation (1) gives:

[0065] lnI=ln C-2lnR (2)

[0066] In theory, the air kerma rate as a function of distance satisfies equations (1) and (2). However, in a real reference radiation field, this relationship needs to be verified.

[0067] Converting the target air kerma rate into target distance is specifically as follows:

[0068] 1) Select N reference points in the reference radiation field and obtain the distance of each reference point from the radiation source and the air kerma rate at the corresponding reference point;

[0069] Specifically, N reference points are selected in the reference radiation field, and the distance from the i-th reference point to the radiation source is R. i (i = 1, 2, ..., N), the conventional value of the air kerma rate at the i-th reference point is K, measured using a standard ionization chamber. i R i With K i Enter the information into the host computer software in sequence.

[0070] 2) Process and fit the collected data;

[0071] Specifically, the PLC processes and fits the collected data, as shown in the flowchart below. Figure 6 As shown. First, collect the R... i With K i Taking the logarithm of each array, we get ln R.i ln K i The least squares formula (3) is used to fit ln R and ln K. According to the requirements of GB / T12162.1, the air kerma rate of the reference point should be proportional to the distance from the radiation source to the reference point within 5%. Therefore, after obtaining the fitted curve, its accuracy must be judged. If the above requirements are met, the fitted curve parameters can be entered into the PLC. Otherwise, the user will be prompted to re-enter R. i K i .

[0072]

[0073] 3) Substitute the target dose rate into the fitted curve to obtain the corresponding distance;

[0074] Specifically, the PLC is configured as follows: Figure 7 The procedure shown will target dose rate K. x Substituting the values ​​into the fitted curve lnK=k×lnR+b, we can obtain the corresponding distance R. x .

[0075] It should be noted that, in order to ensure that the trolley moves within the upper and lower limit positions, it is necessary to adjust the calculated R. x Make judgments to ensure the safe operation of the trolley.

[0076] As can be seen from the above embodiments, the control module of this invention is installed on the trolley device, realizing the electromechanical integration of the control module and the trolley device. Therefore, most signals can be processed locally, and most equipment can be powered locally, greatly reducing the wiring between the trolley device and the control room in the laboratory and effectively improving the system integration. Furthermore, a fault information transmission channel and fault handling scheme are set up between the PLC and the servo motor, effectively ensuring the safe and stable operation of the device. Using the servo motor as the actuator forms a closed-loop control of the position parameters, ensuring positioning accuracy. Simultaneously, by fitting and calculating the data collected by the PLC, trolley positioning at any air kerma rate in the reference radiation field is achieved, improving the intelligence of the device to a certain extent. According to the experimental procedure input by the user on the host computer interface, the PLC controls the trolley to automatically move to the set position and perform the irradiation operation, improving the automation level of the trolley device and reducing repetitive labor for experimental personnel.

[0077] The present invention is not limited to the embodiments described in the specific implementation. Other implementation methods derived by those skilled in the art based on the technical solution of the present invention also fall within the scope of the technical innovation of the present invention.

Claims

1. A PLC-based automatic control system for positioning a reference radiation field guide rail, characterized in that, include: The system includes a trolley translation drive assembly, a trolley lateral movement drive assembly, a trolley lifting drive assembly, a trolley rotation drive assembly, a circuit box, and a control module. The trolley translation drive assembly drives the trolley to move and position horizontally. The trolley lateral movement drive assembly drives the trolley to move laterally and position horizontally. The trolley lifting drive assembly drives the trolley to lift and position vertically. The trolley rotation drive assembly drives the trolley to rotate and position. The circuit box is mounted on the trolley, and the control module is located inside the circuit box and is used to control the trolley translation drive assembly, the trolley lateral movement drive assembly, the trolley lifting drive assembly, and the trolley rotation drive assembly. The control module includes a horizontal motion servo driver and a PLC; The PLC-based reference radiation field guide rail positioning automatic control system includes a horizontal movement servo motor, a horizontal movement reducer, a horizontal lower limit switch, a horizontal upper limit switch, a horizontal origin switch, and a horizontal movement camera. The PLC-based reference radiation field guide rail positioning automatic control system includes a horizontal rotation servo motor, a horizontal circumferential origin switch, and a horizontal rotation camera. It also includes a PLC-based automatic control method for guide rail positioning of reference radiation field, comprising the following steps: S1, Design the experimental process on the host computer interface and input the PLC variables involved in the experimental process; S2, the PLC reads the experimental process variables, converts the target air kerma rate into the target distance, and sends the corresponding number of pulse commands to the horizontal movement servo driver. After the horizontal movement servo motor rotates to the position, it sends feedback to the PLC. S3, after moving horizontally into position, control the horizontal turntable to rotate to the first angle, and after the horizontal rotation servo motor rotates to the position, send feedback to the PLC; S4, after the horizontal turntable rotates to the correct position, irradiation begins. The time accumulator inside the PLC starts and ends after the preset time is reached. S5, read the next turntable angle, repeat steps S3 and S4 until the experimental repetition number is reached; In the control method, converting the target air kerma rate into the target distance specifically involves: Select N reference points in the reference radiation field and obtain the distance of each reference point from the radiation source and the air kerma rate at the corresponding reference point; The collected data is processed and fitted. The target dose rate is substituted into the fitted curve to obtain the corresponding distance.

2. The PLC-based automatic control system for positioning a reference radiation field guide rail as described in claim 1, characterized in that: The control module also includes a horizontal traverse servo driver, a vertical lift servo driver, a horizontal rotation servo driver, an air switch, a first switching power supply, a second switching power supply, a DC power distribution terminal, a main power terminal, a grounding terminal, a neutral terminal, a first external power supply terminal, a second external power supply terminal, a PLC digital input terminal, and a PLC digital output terminal. The PLC includes a CPU module, a Modbus communication module, and a digital input module. The external power supply line enters the control circuit through the main power terminal. The live wire goes to different electrical devices through the air switch, the neutral wire goes to different devices through the neutral terminal, and the ground wire goes to different electrical devices through the grounding terminal. The horizontal movement servo drive, horizontal transverse movement servo drive, vertical lifting servo drive, and horizontal rotation servo drive control the four degrees of freedom of the carriage, and communicate with the PLC using pulse commands. The first switching power supply supplies power to the PLC through the DC power distribution terminal and supplies power to each photoelectric switch on the carriage through the first external power supply terminal. The second switching power supply supplies power to each miniature camera on the carriage through the second external power supply terminal. The CPU module processes the collected signals according to the written program and outputs signals to each servo drive through the PLC digital output terminal. The CPU module includes a network interface for remote connection between the PLC and the host computer interface. The Modbus communication module is connected to the communication port of the servo drive for querying the alarm parameters of the drive. The digital input module collects external sensor signals and transmits them to the CPU module. The external sensor signals enter the PLC through the PLC digital input terminal.

3. The PLC-based automatic control system for positioning a reference radiation field guide rail as described in claim 1, characterized in that: The horizontal movement servo motor and the horizontal movement reducer drive the belt to rotate. The horizontal lower limit switch, the horizontal upper limit switch, the horizontal origin switch, and the horizontal movement camera are used to achieve positioning of the trolley's horizontal movement.

4. The PLC-based automatic control system for positioning a reference radiation field guide rail as described in claim 1, characterized in that: The PLC-based reference radiation field guide rail positioning automatic control system includes a horizontal traverse servo motor, a horizontal lower limit switch, a horizontal upper limit switch, a horizontal origin switch, and a horizontal traverse camera; wherein, the horizontal traverse servo motor is used to drive the trolley to move horizontally, and the horizontal lower limit switch, the horizontal upper limit switch, the horizontal origin switch, and the horizontal traverse camera are used to realize the positioning of the trolley during horizontal traverse.

5. The PLC-based automatic control system for positioning a reference radiation field guide rail as described in claim 1, characterized in that: The PLC-based reference radiation field guide rail positioning automatic control system includes a vertical lifting servo motor, a vertical lower limit switch, a vertical upper limit switch, and a vertical origin switch; wherein, the vertical lifting servo motor is used to drive the lifting and lowering of the trolley, and the vertical lower limit switch, the vertical upper limit switch, and the vertical origin switch are used to realize the positioning of the trolley lifting and lowering.

6. The PLC-based automatic control system for positioning a reference radiation field guide rail as described in claim 1, characterized in that: The horizontal rotation servo motor is used to drive the trolley to rotate horizontally, and the horizontal circumferential origin switch and the horizontal rotation camera are used to achieve positioning of the trolley's horizontal rotation.

7. The PLC-based automatic control system for positioning a reference radiation field guide rail as described in claim 2, characterized in that: The PLC-based reference radiation field guide rail positioning automatic control system also includes a remote control handle, which is connected to the PLC input terminal and is used to control the vehicle to move forward and backward horizontally; move left and right horizontally; move up and down vertically; and rotate clockwise and counterclockwise horizontally.

8. The PLC-based automatic control system for positioning a reference radiation field guide rail as described in claim 2, characterized in that: The PLC-based automatic control system for positioning the reference radiation field guide rail also includes a laser calibrator, which emits horizontal and vertical cross laser lines that are aligned with the position of the radiation source to determine the irradiation position.

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