Control system and method for automatic out-of-step cancellation during selective valve positioning movement

Abstract

The application provides a control system and control method for eliminating step loss in the positioning movement of a selection valve. The number of photoelectric pulses is determined by combining a photoelectric sensor and a special encoding disc for physical alignment of the execution hole position of the selection valve. In the movement process of the actuator, the actual number of photoelectric pulses of the special encoding disc is obtained by the photoelectric sensor. When the actual number of photoelectric pulses is consistent with the theoretical number of photoelectric pulses, the corresponding number of steps of the hole position offset is started to be executed. Finally, the execution hole position of the selection valve stays at the correct position, so that the automatic elimination of step loss in the positioning movement of the selection valve is realized. Since the direct alignment of the special encoding disc and the photoelectric sensor is adopted, the process is simple and the cost is low. Through the setting of the pulse number parameter mode for the continuous movement of the encoding disc and the selection valve hole position after matching, the alignment is accurate.

Description

Technical Field

[0001] This invention belongs to the technical field of liquid chromatographs, and particularly relates to a control system and method for automatically offsetting step loss during the positioning and movement of a selector valve. Background Technology

[0002] A liquid chromatograph (LC) is an instrument that separates and analyzes mixtures by utilizing the differences in the partition ratios of a mixture between a liquid and a solid or between two immiscible liquids. A typical LC system consists of a reservoir, pump, injector, column, detector, and recorder. The mobile phase in the reservoir is pumped into the system by a high-pressure pump. The sample solution enters the mobile phase through the injector and is carried into the stationary phase of the column. Because the components in the sample solution have different partition coefficients in the two phases, they undergo repeated adsorption-desorption processes during relative motion, resulting in significant differences in their migration velocities. These components are separated into individual components that elute sequentially from the column. Upon passing through the detector, the sample concentration is converted into an electrical signal and transmitted to the recorder. The detection results are output as a chromatogram. The solvent selection valve is a mechanism in the LC system used to select the solvent. LC systems typically contain multiple independent solvent bottles, and the solvent selection valve can select a binary mixture from these bottles.

[0003] Existing examples, such as Chinese patent CN207921376U, entitled "A Multi-channel Solvent Selection Valve for a Liquid Chromatograph," include a slide rod with a slider slidably connected to it. The slider is screwed with a locking bolt, and a valve body A is fixedly connected to the top of the slider. An inlet pipe is fixedly connected to one side of the valve body B. A valve core is located inside valve body A, with a through hole in its center. A control rod A is fixedly connected to the top of the valve core. An outlet is located on the other side of valve body A, with a threaded hose fixedly connected to it. The other end of the threaded hose is fixedly connected to the inlet of valve body B. A shut-off valve A is located on the threaded hose near valve body B. This solvent selection valve has a simple structure and is easy to use. Through the two control switches fixed on the slide rod and the meshing of gears, if one switch fails during use, the other can be used directly without interrupting the normal operation of the device. Furthermore, the flow rate of the solvent within the entire device is controlled by a ball valve core and multiple node control throttling valves. By installing an actuator in a liquid chromatograph to move the solvent selection valve, it can be used for automatic selection of multiple mobile phase components in unattended operation. However, during the contact between the selection valve and various chemical solvents, if the valve core encounters a highly viscous reagent or certain special solvents, a slow chemical reaction can easily occur, causing the valve core to expand and deform. This results in a geometric increase in the frictional force on the valve core end face, causing the actuator to lose a lot of steps during the movement of the selection valve. Ultimately, this leads to a large offset in the position of the selection valve's actuator orifice, blockage of the solvent channel, and errors in the solvent selection result. Summary of the Invention

[0004] This invention provides a control system and method for automatically canceling out-of-step movement during the positioning and movement of a selector valve, aiming to solve the problems mentioned in the background art.

[0005] The control system and method for automatic compensation of step loss during the positioning and movement of a selector valve provided by this invention are as follows:

[0006] A control system for automatically canceling out-of-step movement during the positioning and movement of the selector valve is installed between the actuator and the selector valve. The actuator is a motor. The control system includes: a photoelectric sensor, a specially designed encoder disk, signal lines, and a main controller. The transmitter of the photoelectric sensor is located outside the specially designed encoder disk. The light beam emitted by the transmitter of the photoelectric sensor illuminates the specially designed encoder disk. The specially designed encoder disk is circular in shape. Multiple light-free areas are opened on the ring of the specially designed encoder disk as signal recognition points. The upper and lower sides of the specially designed encoder disk are connected.

[0007] The main controller controls the connected motor. A signal line connects the main controller and the receiver of the photoelectric sensor. The front shaft extension of the motor is located on the upper side of the special encoder disk. The selection valve is located on the lower side of the special encoder disk. The front shaft extension of the motor is connected to the selection valve, and the connection point between the two is located inside the inner circle of the ring of the special encoder disk.

[0008] Preferably, the signal recognition points of the specially designed encoder disk include: a zero-position recognition point and multiple pulse recognition points, which are arranged circumferentially.

[0009] A method for a control system that automatically cancels out-of-step movement during the positioning and movement of a selector valve includes the following steps:

[0010] System power-on initialization: The main controller determines whether the control system has been successfully initialized based on whether the initialization success flag is set; if the initialization success flag is not set, the main controller determines that the control system has been successfully initialized; if the initialization success flag is set, the main controller determines that the control system has failed to initialize; if the control system is successfully initialized, the control system enters a waiting state and prepares to execute the target position execution process; if the control system fails to initialize, the initialization process is restarted.

[0011] Initialization execution process: The main controller calculates the number of motor steps in the unshaded area of ​​the pulse recognition point on the special encoder disk based on the width of the unshaded area and the number of motor steps per unit time using a limiting average filtering algorithm. The photoelectric sensor monitors the duration and number of photoelectric pulses in the unshaded area of ​​the pulse recognition point on the special encoder disk. When the number of photoelectric pulses is greater than 3, the main controller calculates the number of motor steps in the unshaded area of ​​the zero-position recognition point on the special encoder disk based on the width of the unshaded area and the number of motor steps per unit time using a limiting average filtering algorithm. The main controller determines whether the number of motor steps in the unshaded area of ​​the zero-position recognition point is more than twice the number of motor steps in the unshaded area of ​​the pulse recognition point. If the result is yes, the main controller determines that the initialization of the control system is successful and sets the current position parameter variable of the selector valve to 1. This position parameter variable is regarded as a successful initialization marker.

[0012] Target position execution process: The photoelectric sensor acquires the target position parameter information of the selector valve's execution orifice. The main controller calculates the theoretical number of pulses in a specially designed encoder disk corresponding to the relative angle between the current position of the selector valve and the target position. The main controller controls the motor to drive the selector valve to start moving. The photoelectric sensor acquires the monitored photoelectric pulse count. When the main controller confirms that the monitored photoelectric pulse count is consistent with the theoretical photoelectric pulse count, the main controller controls the motor to start decelerating, so that the motor performs the motor steps corresponding to the offset angle of the selector valve's execution orifice position, causing the selector valve to reach the target position. The offset angle is equal to the relative angle. After the selector valve stops moving, the main controller determines whether the monitored photoelectric pulse count is equal to the theoretical photoelectric pulse count. If the monitored photoelectric pulse count is equal to the theoretical photoelectric pulse count, the selector valve's execution orifice position remains at the target position. If the monitored photoelectric pulse count is not equal to the theoretical photoelectric pulse count, the initialization success mark is reset to 0, and the execution process and target position execution process are re-initialized.

[0013] Preferably, the amplitude-limiting average filtering algorithm in the initialization process is:

[0014] S1. The distance the motor moves forward in one step is fixed. The photoelectric sensor directly obtains the duration of the unshaded area on the special encoder disk. The duration of the widest unshaded area on the special encoder disk is the longest duration. The main controller calculates the number of steps the motor takes in the unshaded area on the special encoder disk. The number of steps the motor takes in the widest unshaded area on the special encoder disk is the maximum value, and the number of steps the motor takes in the narrowest unshaded area on the special encoder disk is the minimum value. The time period of passing through one unshaded area on the special encoder disk is calculated.

[0015] S2. The main controller measures the number of motor execution steps in the unshaded area of ​​the special encoder disk within the longest maintenance period of the unshaded area on the special encoder disk measured by multiple photoelectric sensors, and takes the median as the number of motor execution steps in the unshaded area of ​​the special encoder disk currently obtained by the main controller.

[0016] S3. If the number of motor execution steps in the current unshaded area on the special encoder disk obtained by the main controller is between the maximum and minimum values, then the number of motor execution steps in the current unshaded area on the special encoder disk obtained by the main controller is reasonable, and the number of photoelectric pulses monitored by the photoelectric sensor is incremented by 1.

[0017] Preferably, the relationship between the relative angle of movement from the current position to the target position in the target position execution process and the theoretical number of photoelectric pulses in the specially designed encoding disk is as follows:

[0018] N 理论 =(θ 相对 ( / 360°)×n 总

[0019] N 理论 —Theoretical photoelectric pulse count;

[0020] θ 相对 —The relative angle by which the selector valve moves from its current position to the target position;

[0021] n 总 —The total number of unshaded areas on the specially designed coded disk.

[0022] Preferably, the correspondence between the valve actuation orifice offset angle and the number of motor execution steps in the target position execution process is as follows:

[0023] γ 执行 =(θ 偏移 / 360°)×γ 总

[0024] γ 执行 —Number of steps executed by the motor;

[0025] θ 偏移 —Select the valve's orifice offset angle;

[0026] γ 总 — The number of motor steps that the motor takes to complete one revolution around a specially designed encoder disk.

[0027] Preferably, if the number of photoelectric pulses monitored after the motor stops moving and the theoretical number of photoelectric pulses are not equal more than 3 times in the target position execution process, the main controller will determine that the target position execution is abnormal, re-initialize the execution process until the initialization is successful, and then proceed with the target execution process.

[0028] Compared with the prior art, the present invention has the following technical effects:

[0029] 1. The control system and method for automatic compensation of step loss during the positioning and movement of the selector valve provided by this invention utilizes a combination of a set of photoelectric sensors and a specially designed encoder disk for physical alignment of the selector valve orifice to measure the number of photoelectric pulses. During the movement of the actuator, the photoelectric sensors acquire the measured number of photoelectric pulses from the specially designed encoder disk. When the measured number of photoelectric pulses matches the theoretical number of photoelectric pulses, the number of steps corresponding to the orifice offset is executed, ultimately ensuring that the selector valve's orifice position is correctly positioned. This achieves automatic compensation of step loss during the positioning and movement of the selector valve. The use of a customized simplified encoder disk simplifies the process and reduces costs. Setting the pulse count parameter after the encoder disk matches the selector valve orifice position ensures accurate alignment.

[0030] 2. The control system and method for automatic cancellation of out-of-step movement during the positioning and movement of the selector valve provided by the present invention intervenes in the abnormal situation where the theoretical number of photoelectric pulses and the monitored number of photoelectric pulses are not equal after the movement stops, and repeats the initialization execution process and the target position execution process to correct the selection result of the automatic cancellation of out-of-step movement in the control system, which is conducive to further improving the positioning accuracy of the control system.

[0031] 3. The control system and method for automatic compensation of step loss during the positioning and movement of the selector valve provided by the present invention uses an ARM main control board as the main controller. The ARM main control board refers to a computer embedded microcontroller, which can be embedded in any micro or small instrument and device. It can be stably matched with the liquid chromatography system and has low energy consumption cost.

[0032] 4. The control system and method for automatically canceling out-of-step movement during the positioning and movement of the selector valve provided by the present invention, by setting a special encoder disk between the front shaft extension end of the motor and the selector valve, facilitates the detection and feedback of out-of-step movement, and further improves the positioning accuracy of the control system.

[0033] 5. The control system and method for automatic compensation of step loss during the positioning and movement of the selector valve provided by the present invention, through system power-on initialization, initialization execution process, and target position execution process, adopts a combination of special encoder disk and algorithm. By marking the initialization success and repeatedly confirming the correctness of the execution hole position, random interference signals such as pulse interference can be eliminated, achieving the effects of strong anti-interference capability, wide anti-step loss range, and accurate positioning. Attached Figure Description

[0034] Figure 1 This is an assembly diagram of the control system for automatically canceling out step loss during the positioning and movement of the selector valve provided by the present invention;

[0035] Figure 2 This is an installation diagram of a specially designed encoder disk that automatically cancels out-of-step movement during the positioning and movement of the selector valve, as provided by the present invention.

[0036] Figure 3 This is a schematic diagram of the system structure for automatic compensation of step loss during the positioning and movement of the selector valve provided by the present invention;

[0037] Figure 4 The flowchart of the method for automatically canceling out-of-step movement during the positioning and movement of the selector valve provided by the present invention.

[0038] Reference numerals: 1. Photoelectric sensor; 2. Special encoder disk; 21. Zero position identification point; 22. Pulse identification point; 3. Signal line; 4. Main controller; 5. Motor; 6. Selector valve. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present application and with reference to the accompanying drawings.

[0040] A control system for automatically offsetting step loss during the positioning and movement of the selector valve 6 is installed between the actuator and the selector valve 6. The actuator is a motor 5, which drives the selector valve 6 to position and move, thus making the final selection of the actuation orifice position of the selector valve 6. (Refer to...) Figure 1-3 The control system includes: a photoelectric sensor 1, a specially designed encoder disk 2, signal lines 3, and a main controller 4. The transmitter of the photoelectric sensor 1 is located on the outside of the specially designed encoder disk 2. The photoelectric sensor 1 is a device that converts light signals into electrical signals, including a transmitter and a receiver. Its working principle is based on the photoelectric effect, which refers to the phenomenon where electrons in a substance absorb the energy of photons and produce corresponding electrical effects when a light beam emitted by the transmitter shines on it. The light beam emitted by the transmitter of the photoelectric sensor 1 shines on the specially designed encoder disk 2, which is circular in shape. Multiple unobstructed areas are formed on the ring of the specially designed encoder disk 2 as signal recognition points. The signal recognition points include: a zero-position recognition point 21 and multiple pulse recognition points 22, which are arranged circumferentially. The top and bottom sides of the specially designed encoder disk 2 are connected. The main controller 4 uses an ARM main control board, which refers to a computer embedded microcontroller that can be embedded in any micro or small instrument. The main controller 4 controls the connected motor 5. A signal line 3 connects the main controller 4 and the receiver of the photoelectric sensor 1. The front shaft extension of the motor 5 is located on the upper side of the special encoder disk 2. The selector valve 6 is located on the lower side of the special encoder disk 2. The front shaft extension of the motor 5 is connected to the selector valve 6, and the connection point of the two is located inside the inner circle of the ring of the special encoder disk 2, so that the actuation hole of the selector valve 6 and the signal recognition point on the special encoder disk 2 are directly physically opposite each other.

[0041] The control method based on the automatic compensation of step loss during the positioning and movement of the selector valve includes the following steps:

[0042] System power-on initialization: The main controller 4 determines whether the control system has been successfully initialized based on whether the initialization success flag is set. If the main controller 4 checks that the initialization success flag is not set, it determines that the control system has been successfully initialized. If the main controller 4 checks that the initialization success flag is set, it determines that the control system has failed to initialize. If the main controller 4 determines that the control system has been successfully initialized, the control system enters a waiting state and prepares to execute the target position execution process. If the main controller 4 determines that the control system has failed to initialize, it restarts the initialization process.

[0043] Initialization execution process: The main controller 4 calculates the number of motor steps in the unshaded area of ​​the pulse recognition point 22 on the special encoder disk 2 through the amplitude limiting average filtering algorithm. The photoelectric sensor 1 monitors the maintenance time and the number of photoelectric pulses in the unshaded area of ​​the pulse recognition point 22 on the special encoder disk 2.

[0044] The amplitude-limited averaging filtering algorithm is as follows:

[0045] S1. The distance that motor 5 moves forward in one step is fixed. Photoelectric sensor 1 directly obtains the duration of the unshaded area on the special encoder disk 2. The duration of the widest unshaded area on the special encoder disk 2 is the longest duration. The main controller 4 calculates the number of steps that motor 5 executes in the unshaded area on the special encoder disk 2. The number of steps that motor 5 executes in the widest unshaded area on the special encoder disk 2 is the maximum value, and the number of steps that motor 5 executes in the narrowest unshaded area on the special encoder disk 2 is the minimum value.

[0046] S2. The main controller 4 calculates the number of motor 5 execution steps in the unshaded area of ​​the special encoder disk 2 within the longest maintenance period of the unshaded area directly obtained by multiple photoelectric sensors 1, and takes the median as the number of motor 5 execution steps in the current unshaded area of ​​the special encoder disk 2 obtained by the main controller 4.

[0047] S3. If the number of steps executed by the motor 5 in the current unshaded area on the special encoder disk 2 obtained by the main controller 4 is between the maximum and minimum values, then the number of steps executed by the motor 5 in the current unshaded area on the special encoder disk 2 obtained by the main controller 4 is reasonable, and the number of photoelectric pulses monitored by the photoelectric sensor 1 is incremented by 1.

[0048] When the number of photoelectric pulses is greater than 3, the main controller 4 calculates the number of steps executed by motor 5 in the unshaded area of ​​the zero-position identification point 21 on the special encoder disk 2 using a limiting average filtering algorithm. The main controller 4 then determines whether the number of steps executed by motor 5 in the unshaded area of ​​the zero-position identification point 21 is more than twice the number of steps executed by motor 5 in the unshaded area of ​​the pulse identification point 22. If the result is yes, the main controller 4 determines that the control system initialization is successful, and simultaneously sets the position parameter variable corresponding to the selector valve 6 to 1 in the software. This position parameter variable is considered a successful initialization marker. Setting is a way to map the input to the output by externally forcibly changing the input. Resetting is to change the input value back to the initial state when powered on through the program. For example, a module with parameter variables may initially have no output, output 1 after setting, and then become 0 again after resetting.

[0049] Target position execution process: Photoelectric sensor 1 acquires the target position parameter information of the selector valve 6's execution orifice. The main controller 4 calculates the theoretical number of pulses in the specially designed encoder disk 2 corresponding to the relative angle between the current position and the target position of the selector valve 6. The correspondence between the relative angle of movement from the current position to the target position and the theoretical number of photoelectric pulses in the specially designed encoder disk 2 is as follows:

[0050] N 理论 =(θ 相对 ( / 360°)×n 总

[0051] N 理论 —Theoretical photoelectric pulse count;

[0052] θ 相对 —Select valve 6 moves from its current position to the target position by a relative angle;

[0053] n 总 —The total number of unshaded areas on the special coding disk 2.

[0054] The main controller 4 controls the motor 5 to drive the selector valve 6 to start moving. The photoelectric sensor 1 acquires the number of monitored photoelectric pulses. When the main controller 4 confirms that the number of monitored photoelectric pulses is consistent with the theoretical number of photoelectric pulses, the main controller 4 controls the motor 5 to start decelerating. The motor 5 executes the number of steps corresponding to the orifice offset angle of the selector valve 6 to reach the target position. The offset angle is equal to the relative angle. The correspondence between the orifice offset angle of the selector valve 6 and the number of steps executed by the motor 5 is as follows:

[0055] γ 执行 =(θ 偏移 / 360°)×γ 总

[0056] γ 执行 —Number of steps executed by motor 5;

[0057] θ 偏移 —Select valve 6 to offset the orifice position angle;

[0058] γ 总 —The number of steps for motor 5 to perform one revolution around the specially designed encoder disk 2.

[0059] After the selector valve 6 stops moving, the main controller 4 determines whether the number of monitored photoelectric pulses is equal to the theoretical number of photoelectric pulses. If the number of monitored photoelectric pulses is equal to the theoretical number of photoelectric pulses, the actuator of the selector valve 6 stays at the target position. If the number of monitored photoelectric pulses is not equal to the theoretical number of photoelectric pulses, the initialization success flag is reset to 0, and the execution process and the target position execution process are re-initialized.

[0060] If the number of photoelectric pulses monitored after the motor 5 stops moving is not equal to the theoretical number of photoelectric pulses more than 3 times, the main controller 4 will determine that the target position execution is abnormal, re-initialize the execution process until the initialization is successful, and then resume the target execution process until the selection valve 6 is set to the target position.

[0061] The principle of this embodiment is as follows: the number of photoelectric pulses is measured by combining a set of photoelectric sensors 1 with a specially designed encoder 2 for physical alignment of the orifice position of the selector valve 6. During the movement of the actuator, the photoelectric sensor 1 obtains the measured number of photoelectric pulses from the specially designed encoder 2. When the measured number of photoelectric pulses matches the theoretical number of photoelectric pulses, the number of steps corresponding to the offset of the orifice position is reduced. Finally, the orifice position of the selector valve 6 stops at the correct position, thereby achieving automatic compensation of step loss during the positioning and movement of the selector valve 6. The use of a specially designed encoder makes the process simple and the cost low. The accuracy of the alignment is achieved by setting the pulse count parameter after the encoder and the orifice position of the selector valve 6 are matched.

[0062] Example 2:

[0063] After power-on, the control system for offsetting the loss of steps during the positioning and movement of the selector valve 6 begins initialization. The ARM main control board determines whether the current position parameter information of the selector valve 6 is displayed as 1. If the result is no, the control system needs to be initialized.

[0064] The photoelectric sensor 1 directly acquires the duration and number of photoelectric pulses of the unshaded area of ​​the pulse recognition point 22 on the special encoder disk 2. The ARM main control board obtains the correct number of motor steps in the unshaded area of ​​the pulse recognition point 22 on the special encoder disk 2. Since the number of steps executed by motor 5 per unit time is known, the ARM main control board calculates the product of the duration and the number of steps executed by motor 5 per unit time to obtain the number of steps executed by motor 5 in the unshaded area of ​​the special encoder disk 2. The motor step count of the widest unshaded area on the special encoder disk 2 is the maximum value, and the motor step count of the narrowest unshaded area on the special encoder disk 2 is the minimum value. The photoelectric sensor 1 directly acquires the longest duration of the widest unshaded area on the specially designed encoder disk 2. The ARM main control board calculates the number of motor 5 execution steps in the unshaded area of ​​the pulse recognition point 22 on the specially designed encoder disk 2 within the longest duration of the unshaded area acquired by multiple photoelectric sensors 1, and takes the median as the number of motor 5 execution steps in the unshaded area of ​​the pulse recognition point 22 on the specially designed encoder disk 2 acquired by the ARM main control board. Similarly, the number of motor 5 execution steps in the unshaded area of ​​the zero-position recognition point 21 on the specially designed encoder disk 2 can be obtained. When the number of photoelectric pulses is greater than 3, the ARM main control board determines whether the number of motor 5 execution steps in the unshaded area of ​​the zero-position recognition point 21 is more than twice the number of motor 5 execution steps in the unshaded area of ​​the pulse recognition point 22. If the result is yes, the ARM main control board determines that the control system initialization is successful, and at the same time, sets the position parameter variable corresponding to the current selection valve 6 to 1 in the software. This position parameter variable is regarded as a successful initialization marker.

[0065] The photoelectric sensor 1 directly acquires the target position of the orifice of the selector valve 6. The ARM main control board calculates the theoretical number of pulses in the specially designed encoder disk 2 corresponding to the relative angle between the current position of the selector valve 6 and the target position using the formula in Example 1, with reference to a certain peripheral device and the relative displacement. The ARM main control board controls the motor 5 to drive the selector valve 6 to start moving. The photoelectric sensor 1 acquires the number of monitored photoelectric pulses. When the ARM main control board confirms that the number of monitored photoelectric pulses is consistent with the theoretical number of photoelectric pulses, the ARM main control board controls the motor 5 to start decelerating, so that the motor 5 executes the motor corresponding to the offset angle of the orifice of the selector valve 6. Five steps are required to bring the selector valve 6 to the target position, with the offset angle equal to the relative angle. The ARM main control board calculates the number of steps to be executed by the motor 5 based on the offset angle of the selector valve 6's execution hole and the relevant formula in Example 1. After the selector valve 6 stops moving, the ARM main control board checks whether the monitored photoelectric pulse count is equal to the theoretical photoelectric pulse count. If they are equal, the execution hole of the selector valve 6 remains at the target position. If they are not equal, the initialization success flag is reset to 0, and the flag is re-initialized to confirm the correct target position. If the discrepancy between the monitored and theoretical photoelectric pulse counts occurs more than three times after the motor 5 stops moving, the ARM main control board determines that the target position execution is abnormal, re-initializes the flag until it is successful, and then controls the motor 5 to drive the selector valve 6 to lower the execution hole to the target position.

[0066] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A method for a control system that automatically cancels out-of-step movement during valve positioning, characterized in that, The control system is located between the actuator and the selector valve (6). The actuator is a motor (5). The control system includes: a photoelectric sensor (1), a special encoder disk (2), a signal line (3), and a main controller (4). The transmitter of the photoelectric sensor (1) is located outside the special encoder disk (2). The light beam emitted by the transmitter of the photoelectric sensor (1) illuminates the special encoder disk (2). The special encoder disk (2) is in the shape of a ring. Multiple non-light-blocking areas are opened on the ring of the special encoder disk (2) as signal identification points. The upper and lower sides of the special encoder disk (2) are connected. The main controller (4) controls the connected motor (5). A signal line (3) is connected between the main controller (4) and the receiver of the photoelectric sensor (1). The front shaft extension of the motor (5) is located on the upper side of the special encoder disk (2). The selection valve (6) is located on the lower side of the special encoder disk (2). The front shaft extension of the motor (5) is connected to the selection valve (6), and the connection point of the two is located inside the inner circle of the ring of the special encoder disk (2). The signal identification points of the specially designed encoder disk (2) include: a zero-position identification point (21) and multiple pulse identification points (22), which are arranged circumferentially; The method for automatically canceling out-of-step control during the positioning and movement of the selector valve includes the following steps: System power-on initialization: The main controller determines whether the control system has been successfully initialized based on whether the initialization success flag is set; if the initialization success flag is not set, the main controller determines that the control system has been successfully initialized; if the initialization success flag is set, the main controller determines that the control system has failed to initialize; if the control system is successfully initialized, the control system enters a waiting state and prepares to execute the target position execution process; if the control system fails to initialize, the initialization process is restarted. Initialization execution process: The main controller calculates the number of motor steps in the unshaded area of ​​the pulse recognition point on the special encoder disk based on the width of the unshaded area and the number of motor steps per unit time using a limiting average filtering algorithm. The photoelectric sensor monitors the duration and number of photoelectric pulses in the unshaded area of ​​the pulse recognition point on the special encoder disk. When the number of photoelectric pulses is greater than 3, the main controller calculates the number of motor steps in the unshaded area of ​​the zero-position recognition point on the special encoder disk based on the width of the unshaded area and the number of motor steps per unit time using a limiting average filtering algorithm. The main controller determines whether the number of motor steps in the unshaded area of ​​the zero-position recognition point is more than twice the number of motor steps in the unshaded area of ​​the pulse recognition point. If the result is yes, the main controller determines that the initialization of the control system is successful and sets the current position parameter variable of the selector valve to 1. This position parameter variable is regarded as a successful initialization marker. Target position execution process: The photoelectric sensor acquires the target position parameter information of the selector valve's execution orifice. The main controller calculates the theoretical number of pulses in a specially designed encoder disk corresponding to the relative angle between the current position of the selector valve and the target position. The main controller controls the motor to drive the selector valve to start moving. The photoelectric sensor acquires the monitored photoelectric pulse count. When the main controller confirms that the monitored photoelectric pulse count is consistent with the theoretical photoelectric pulse count, the main controller controls the motor to start decelerating, so that the motor performs the motor steps corresponding to the offset angle of the selector valve's execution orifice position, causing the selector valve to reach the target position. The offset angle is equal to the relative angle. After the selector valve stops moving, the main controller determines whether the monitored photoelectric pulse count is equal to the theoretical photoelectric pulse count. If the monitored photoelectric pulse count is equal to the theoretical photoelectric pulse count, the selector valve's execution orifice position remains at the target position. If the monitored photoelectric pulse count is not equal to the theoretical photoelectric pulse count, the initialization success mark is reset to 0, and the execution process and target position execution process are re-initialized.

2. The method for automatically canceling out-of-step control during the positioning and movement of the selector valve according to claim 1, characterized in that, The amplitude-limiting average filtering algorithm in the initialization process is as follows: S1. The distance the motor moves forward in one step is fixed. The photoelectric sensor directly obtains the duration of the unshaded area on the special encoder disk. The duration of the widest unshaded area on the special encoder disk is the longest duration. The main controller calculates the number of steps the motor takes in the unshaded area on the special encoder disk. The number of steps the motor takes in the widest unshaded area on the special encoder disk is the maximum value, and the number of steps the motor takes in the narrowest unshaded area on the special encoder disk is the minimum value. The time period of passing through one unshaded area on the special encoder disk is calculated. S2. The main controller measures the number of motor execution steps in the unshaded area of ​​the special encoder disk within the longest maintenance period of the unshaded area on the special encoder disk measured by multiple photoelectric sensors, and takes the median as the number of motor execution steps in the unshaded area of ​​the special encoder disk currently obtained by the main controller. S3. If the number of motor execution steps in the current unshaded area on the special encoder disk obtained by the main controller is between the maximum and minimum values, then the number of motor execution steps in the current unshaded area on the special encoder disk obtained by the main controller is reasonable, and the number of photoelectric pulses monitored by the photoelectric sensor is incremented by 1.

3. The method for automatically canceling out-of-step control during the positioning and movement of the selector valve according to claim 1, characterized in that, The relationship between the relative angle of movement from the current position to the target position and the theoretical number of photoelectric pulses in the specially designed encoder disk in the target position execution process is as follows: —Theoretical number of photoelectric pulses; —The relative angle by which the selector valve moves from its current position to the target position; —The total number of unshaded areas on the specially designed coded disk.

4. The method for automatically canceling out-of-step control during the positioning and movement of the selector valve according to claim 1, characterized in that, The correspondence between the valve orifice offset angle and the number of motor execution steps selected in the target position execution process is as follows: —Number of steps executed by the motor; —Select the valve's orifice offset angle; — The number of motor steps that the motor takes to complete one revolution around a specially designed encoder disk.

5. The method for automatically canceling out-of-step control during the positioning and movement of the selector valve according to claim 1, characterized in that, If, during the target position execution process, the number of photoelectric pulses monitored after the motor stops moving is not equal to the theoretical number of photoelectric pulses more than 3 times, the main controller will determine that the target position execution is abnormal, re-initialize the execution process until the initialization is successful, and then proceed with the target execution process.

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