Deep hypothermia gas phase storage system and control method thereof

Abstract

The invention relates to the technical field of biological sample deep hypothermia storage system control and adjustment, in particular to a deep hypothermia gas phase storage system and a control method thereof, and the deep hypothermia gas phase storage system comprises an upper cabin, a liquid nitrogen tank assembly, an aluminum disc assembly, a Stirling loop siphon cold screen and a liquid nitrogen making machine assembly. The control device is composed of a data acquisition module, a motion planning module, a position calibration module and an execution control module, temperature, identification and position data are collected in real time, data fusion and processing are carried out, a control instruction is generated to drive a mechanical transmission mechanism to complete sample access, motion tracks and temperature parameters are dynamically corrected, and closed-loop control flow is formed. The problem of positioning deviation caused by insufficient mechanical transmission precision in the prior art is solved, the risks of sample damage and cross contamination are reduced, and accurate operation of sample access and stable maintenance of a low-temperature environment are realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biological sample cryogenic storage system control adjustment, and in particular to a cryogenic gas phase storage system and a control method thereof. BACKGROUND

[0002] The mechanical transmission system of the gas phase liquid nitrogen storage device is mainly used to complete the automatic access and accurate positioning of the stored samples. The core driving element is usually a stepper motor or a servo motor. The rotary motion of the motor is transmitted to a precision reduction mechanism through a shaft coupling to amplify the output torque and improve the control resolution. The reduced rotary motion can be transmitted through a synchronous belt or a gear mechanism, and finally converted into linear motion. Common conversion mechanisms include ball screws or gear racks.

[0003] The existing mechanical transmission and control system technology of the gas phase liquid nitrogen storage device has the following technical pain points. Specifically, due to the gear gap and motion cumulative error of the existing mechanical transmission mechanism, combined with the response delay of the control system and the imperfect positioning algorithm, the motion trajectory deviation occurs in the biological sample access process. For example, when automatically grabbing the cryogenic tube, inaccurate transmission may cause the gripper assembly to deviate from the target aluminum tube storage position, causing sample tube collision or insertion failure, which in turn causes sample tube rupture, activity loss or cross contamination between adjacent samples, seriously affecting the reliability of long-term storage of biological samples. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a cryogenic gas phase storage system and a control method thereof, which solves the technical problem of inaccurate positioning in the biological sample access process caused by insufficient precision of the existing mechanical transmission and control system, which easily leads to sample damage or cross contamination.

[0005] To solve the above technical problems, the specific content of the present application is as follows: In a first aspect, the present application provides a cryogenic gas phase storage system, which comprises a physical device and a control device. The control device is in communication connection with the physical device and is used to control the physical device to access samples. The physical device comprises an upper cabin, a liquid nitrogen tank assembly, an aluminum disc assembly, a Stirling loop siphon cold screen, a liquid nitrogen making machine assembly and an outer frame. The liquid nitrogen tank assembly and the liquid nitrogen making machine assembly are installed inside the outer frame, and the outer frame is connected with the Stirling loop siphon cold screen. The upper cabin is arranged at the upper part of the outer frame. A linear motor and a motion module are arranged inside the upper cabin. The motion module is connected with a gripper assembly. A bottom sweeping device is arranged at the bottom of the upper cabin. A tank cover is installed at the top of the liquid nitrogen tank assembly. A large gear ring is fixed on the surface of the tank cover of the liquid nitrogen tank assembly and is in meshing transmission with a small gear arranged in the upper cabin. The aluminum disk assembly is housed inside the liquid nitrogen tank of the liquid nitrogen tank assembly. The aluminum disk assembly includes an aluminum disk, a central support rod, an aluminum tube, a temperature sensor fixing rod, and a high-density mesh of aluminum tubes. The aluminum disk is installed on the top of the central support rod, and the aluminum tube and the temperature sensor fixing rod are installed on the bottom of the aluminum disk. The Stirling loop siphon cold shield extends into the liquid nitrogen tank; The control device includes: The data acquisition module is used to collect temperature data from the temperature sensor fixing rod, the identification data of the bottom scanning device, and the position data of the position sensor; The motion planning module is used to receive data from the data acquisition module and calculate the motion trajectory of the gripper component; The position calibration module is used to receive the motion trajectory data of the motion planning module and generate a correction signal based on the real-time monitored position deviation of the gripper component; The execution control module is used to receive the corrected trajectory data from the position calibration module, drive the linear motor and the motion module to move, and control the action of the gripper assembly. The position calibration module sends the correction signal to the motion planning module, which updates the motion trajectory based on the correction signal to form a closed-loop control.

[0006] Furthermore, in the cryogenic gas phase storage system of the present invention, the motion planning module is configured as follows: Parse the target storage coordinates in the user command and access the pre-stored aluminum disk assembly mesh mapping model to determine the precise location of the target aluminum tube; By using the inverse kinematics model, the coordinates of the target aluminum tube are converted into linear displacement commands of the linear motor and rotation angle commands of the motion module; The weighting factor of the path planning is dynamically adjusted based on the temperature data fed back by the temperature sensor fixing rod, wherein the path weight of the higher temperature area is increased to prioritize avoidance; The historical motion error database is invoked to inject a transmission backlash compensation amount associated with the motion direction into the linear displacement command and the rotation angle command; The A* search algorithm is used to calculate the movement path of the gripper component from its current position to the target aluminum tube in the grid mapping model, and a pulse control sequence including pulse frequency and direction is generated and output to the position calibration module.

[0007] Furthermore, in the cryogenic vapor phase storage system of the present invention, the position calibration module is configured as follows: The real-time distance between the gripper assembly and the target aluminum tube is continuously acquired by a laser rangefinder, while the acceleration and angular velocity data of the gripper assembly are collected by an inertial measurement unit. The extended Kalman filter algorithm is used to fuse the real-time distance and inertial measurement data to output the estimated actual position of the gripper component in three-dimensional space. Calculate the Euclidean distance deviation between the actual position estimate and the theoretical trajectory coordinates from the motion planning module; The Euclidean distance deviation is compared with a preset tolerance threshold, which is dynamically set according to the diameter of the aluminum tube. When the deviation exceeds the tolerance threshold, the PID controller is activated, the deviation value is used as input, a correction amount for adjusting the frequency of the pulse control sequence is calculated, and a correction signal including the correction amount is generated and fed back to the motion planning module.

[0008] Furthermore, in the cryogenic vapor phase storage system of the present invention, the execution control module is configured as follows: Receive a pulse control sequence containing the correction amount from the position calibration module; The pulse control sequence is parsed into a corresponding PWM waveform signal, and the linear motor and the servo motor of the motion module are controlled to operate by micro-stepping drive technology, wherein the micro-stepping subdivision is dynamically adjusted according to the correction amount. When the gripper assembly moves to a preset position above the target aluminum tube, an opening command is sent to the drive mechanism of the can lid; After receiving a confirmation signal that the can lid is fully open, the gripper assembly is controlled to perform gripping and insertion actions with a preset current threshold corresponding to the material of the sample tube. After the gripper assembly exits the liquid nitrogen tank, a closing command is sent to the tank lid drive mechanism after a predetermined delay.

[0009] Furthermore, in the cryogenic vapor phase storage system of the present invention, the aluminum disk is made of -T aluminum alloy material, and a high-density mesh of aluminum tubes is provided on the aluminum disk for physical isolation of the sample.

[0010] Furthermore, in the cryogenic vapor phase storage system of the present invention, the Stirling loop siphon cold shield includes a Stirling refrigerator, a siphon heat exchange chamber, a siphon, and a siphon vacuum sleeve; The Stirling refrigerator cools the siphon tube heat exchange chamber, causing gaseous nitrogen to liquefy; The siphon tube is disposed inside the vacuum sleeve of the siphon tube and extends from the heat exchange chamber of the siphon tube to the vicinity of the aluminum disk assembly inside the liquid nitrogen tank; The vacuum sleeve covers the outside of the siphon tube and is used to fix the siphon tube and provide vacuum insulation.

[0011] Furthermore, in the cryogenic vapor phase storage system of the present invention, the operation of the liquid nitrogen generator component is managed by the control device, which is configured to: Continuously monitor the liquid level sensor data and the temperature data of the temperature sensor fixing rod inside the liquid nitrogen tank; When the liquid level is lower than the first threshold or the temperature is higher than the second threshold, a liquid nitrogen replenishment command is generated. The liquid nitrogen generator assembly is activated in response to the liquid nitrogen replenishment command, and delivers the generated liquid nitrogen to the liquid nitrogen tank; When the liquid level reaches the third threshold and the temperature stabilizes within the target range, a stop command is generated, and the liquid nitrogen generator component stops working.

[0012] Furthermore, in the cryogenic vapor phase storage system of the present invention, the data acquisition module is configured as follows: The analog signals of the temperature sensor fixing rod, the image data of the bottom scanning device, and the digital pulse signals of the position sensor are periodically acquired through a digital interface. Cyclic redundancy check is performed on the collected raw data packets. If the check fails, a re-collection mechanism is triggered. The analog and digital pulse signals that pass the verification are smoothed using a Kalman filter algorithm to suppress random noise. The filtered temperature data, image parsing identification data, and location data are normalized using minimum and maximum scaling respectively, and mapped to the interval [, ]. The normalized data, along with the timestamp and data source identifier, is encapsulated into a standardized data packet and output to the motion planning module.

[0013] Furthermore, in the cryogenic gas phase storage system of the present invention, the operation of the motion planning module dynamically adjusting the path planning weight factor based on temperature data is configured to perform: A spatial temperature field model of the aluminum disk assembly is established. The temperature field model is constructed by collecting multi-point temperature data from the temperature sensor fixing rod array, and the storage space is divided into three-dimensional grid cells with temperature attribute values. An initial path weight factor is assigned to each of the three-dimensional mesh cells. The initial path weight factor is positively correlated with the temperature attribute value of the mesh cell. Mesh cells with temperature attribute values ​​exceeding a first temperature threshold are marked as high-temperature avoidance zones, and their path weight factors are set to the maximum value. When calculating the movement path of the gripper assembly from its current position to the target aluminum tube, the path weight factor is introduced as a penalty term in the cost function of the A* search algorithm, so that the algorithm preferentially selects the path that traverses the low-temperature grid cell. During the movement of the gripper component, the motion planning module continuously receives updated temperature data and dynamically refreshes the temperature field model and the corresponding path weight factor accordingly. If a new high-temperature avoidance zone appears on the predetermined path of the gripper component, or if the temperature attribute value of an existing high-temperature avoidance zone continues to rise above the second temperature threshold, the motion planning module will interrupt the current path tracking and replan an optimized path that avoids all high-temperature avoidance zones based on the refreshed weight factor, and send the updated pulse control sequence to the position calibration module.

[0014] Secondly, the present invention provides a control method for a cryogenic vapor phase storage system, applied to the control system of the cryogenic vapor phase storage system as described above, comprising: The steps are as follows: The data acquisition module periodically collects the temperature analog signal from the temperature sensor fixing rod, the image data from the bottom scanning device, and the digital pulse signal from the position sensor; the collected raw data packets are verified, and the verified analog signals and digital pulse signals are smoothed by applying a filtering algorithm, and the processed multi-source data is normalized to generate standardized data packets; The steps and motion planning module receive the standardized data packet, parse the target stored coordinates in the user command and access the pre-stored aluminum disk component mesh mapping model to determine the position of the target aluminum tube; convert the target coordinates into linear displacement commands of the linear motor and rotation angle commands of the motion module through the inverse kinematics model; dynamically adjust the weight factor of the path planning according to the temperature data, call the historical motion error database to inject the transmission backlash compensation amount, use the path search algorithm to calculate the movement path of the gripper component from the current position to the target aluminum tube, and generate a pulse control sequence; The step and position calibration module obtains the actual position estimate of the gripper component through multi-sensor fusion processing, and calculates the Euclidean distance deviation between it and the theoretical trajectory of the motion planning module. When the deviation exceeds the tolerance threshold dynamically set according to the diameter of the aluminum tube, the PID controller generates a pulse frequency correction amount and feeds back the correction signal including the correction amount to the motion planning module to update the motion trajectory. The steps and execution control module receive the corrected pulse control sequence, parse it into a PWM waveform signal, and control the linear motor and motion module to operate through micro-stepping drive technology; when the gripper assembly moves to the preset position above the target aluminum tube, it triggers the can lid opening command; after confirming that the can lid is fully open, it controls the gripper assembly to perform gripping and insertion actions with a current threshold corresponding to the sample tube material, and triggers the can lid closing command after a predetermined delay after exiting the liquid nitrogen tank. The steps form a closed-loop feedback control, and the execution actions of the steps and the calibration results of the steps are coordinated in real time to jointly achieve the positioning and temperature stability control of sample storage and retrieval.

[0015] Beneficial effects of this invention; This invention effectively solves the problem of positioning deviation in biological sample retrieval caused by insufficient precision in existing mechanical transmission and control systems by coordinating the high-precision transmission mechanism and intelligent control module. The data acquisition module filters and normalizes multi-source sensor data to provide accurate input data for the motion planning module. The motion planning module generates an optimized trajectory through inverse kinematics model and dynamic path weight adjustment, and compensates for transmission gaps by combining historical error data. The position calibration module monitors and corrects motion trajectory deviations in real time through multi-sensor fusion and PID control algorithm to form closed-loop feedback control. The execution control module drives the linear motor and motion module to complete precise actions according to the calibrated trajectory, and controls the gripper component force with a current threshold matched to the sample tube material. The high-density mesh structure of the aluminum tube in the aluminum disk component achieves physical isolation of the sample, and the Stirling loop siphon tube cold screen maintains a stable low-temperature environment. The entire system significantly improves the positioning accuracy and reliability of sample retrieval through algorithm compensation and real-time monitoring mechanisms, and reduces the risk of sample damage and cross-contamination. Attached Figure Description

[0016] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the overall structure of the cryogenic vapor phase storage system of the present invention.

[0018] Figure 2 This is a schematic diagram of the internal structure of the upper chamber of the cryogenic gas phase storage system of the present invention.

[0019] Figure 3 This is a schematic diagram of the bottom structure of the upper compartment of the cryogenic vapor phase storage system of the present invention.

[0020] Figure 4 This is a schematic cross-sectional view of the side angle of the deep cryogenic vapor phase storage system of the present invention.

[0021] Figure 5 This is a schematic cross-sectional view of the side of the cryogenic vapor phase storage system of the present invention without the upper compartment installed.

[0022] Figure 6 This is a schematic diagram of the aluminum disk assembly structure of the cryogenic vapor phase storage system of the present invention.

[0023] Figure 7 This is a top view of the aluminum disk assembly of the cryogenic vapor phase storage system of the present invention.

[0024] Explanation of reference numerals in the attached drawings: 1-Upper compartment, 2-Liquid nitrogen tank assembly, 3-Aluminum disc assembly, 31-Aluminum disc, 32-Central support rod, 33-Aluminum tube, 34-Temperature sensor fixing rod, 35-High-density mesh of aluminum tube, 4-Stirling loop siphon cold shield, 41-Siphon heat exchange chamber, 42-Siphon, 43-Siphon vacuum sleeve, 44-Stirling refrigerator, 5-Liquid nitrogen generator assembly, 6-Outer frame, 7-Large gear ring, 8-Linear motor, 9-Motion module, 10-Grab assembly, 11-Bottom sweeping device, 12-Transfer box, 13-Liquid nitrogen tank, 14-Small gear, 15-Tank lid, 16-Outer liner. Detailed Implementation

[0025] To make the technical solution of the present invention clearer, the present invention will be clearly and completely described below with reference to specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The present invention provided by various embodiments will be described in detail below with reference to the accompanying drawings. To better understand the purpose of the present invention, the present invention will be described in further detail below.

[0026] In a first aspect, the present invention provides a cryogenic gas phase storage system, comprising a physical device and a control device, wherein the control device is communicatively connected to the physical device and is used to control the physical device to perform sample storage and retrieval. The physical device includes an upper compartment 1, a liquid nitrogen tank assembly 2, an aluminum disc assembly 3, a Stirling loop siphon cold screen 4, a liquid nitrogen generator assembly 5, and an outer frame 6. The liquid nitrogen tank assembly 2 and the liquid nitrogen generator assembly 5 are installed inside the outer frame 6, and the outer frame 6 is connected to the Stirling loop siphon cold screen 4. The upper compartment 1 is located on the upper part of the outer frame 6. The upper compartment 1 is equipped with a linear motor 8 and a motion module 9. The motion module 9 is connected to a gripper assembly 10. The bottom of the upper compartment 1 is equipped with a bottom sweeping device 11. The liquid nitrogen tank assembly 2 is equipped with a tank cover 15 on its top. A large gear ring 7 is fixed on the surface of the tank cover 15 of the liquid nitrogen tank assembly 2, which meshes with a small gear 14 located in the upper compartment 1 for transmission. The aluminum disk assembly 3 is housed inside the liquid nitrogen tank 13 of the liquid nitrogen tank assembly 2. The aluminum disk assembly 3 includes an aluminum disk 31, a central support rod 32, an aluminum tube 33, a temperature sensor fixing rod 34, and a high-density mesh of aluminum tubes 35. The aluminum disk 31 is installed on the top of the central support rod 32, and the aluminum tube 33 and the temperature sensor fixing rod 34 are installed on the bottom of the aluminum disk 31. The Stirling loop siphon cold shield 4 extends into the interior of the liquid nitrogen tank 13; The control device includes: The data acquisition module is used to collect temperature data from the temperature sensor fixing rod 34, the identification data of the bottom scanning device 11, and the position data of the position sensor; The motion planning module is used to receive data from the data acquisition module and calculate the motion trajectory of the gripper component 10; The position calibration module is used to receive the motion trajectory data of the motion planning module and generate a correction signal based on the real-time monitored position deviation of the gripper component 10. The execution control module is used to receive the corrected trajectory data from the position calibration module, drive the linear motor 8 and the motion module 9 to move, and control the action of the gripper assembly 10. The position calibration module sends the correction signal to the motion planning module, which updates the motion trajectory based on the correction signal to form a closed-loop control.

[0027] The cryogenic gas phase storage system includes physical and control devices. The physical devices consist of an upper chamber 1, a liquid nitrogen tank assembly 2, an aluminum disc assembly 3, a Stirling loop siphon cooling screen 4, a liquid nitrogen generator assembly 5, and an outer frame 6. The upper chamber 1 is located on top of the outer frame 6 and integrates a linear motor 8 and a motion module 9. The motion module 9 is connected to a gripper assembly 10, and a bottom sweeping device 11 is installed at the bottom of the upper chamber 1. A tank cover 15 is installed on the top of the liquid nitrogen tank assembly 2, and a large gear ring 7 is fixed on the surface of the tank cover 15. It meshes with a small gear 14 in the upper chamber 1 to achieve precise rotational positioning. The aluminum disc assembly 3 is housed inside the liquid nitrogen tank 13 of the liquid nitrogen tank assembly 2. The aluminum disc assembly 3 includes an aluminum disc 31, a central support rod 32, an aluminum tube 33, a temperature sensor fixing rod 34, and a high-density mesh of aluminum tubes 35. The aluminum disc 31 is supported by the central support rod 32, and the aluminum tube 33 and the temperature sensor fixing rod 34 are installed at the bottom. The Stirling loop siphon cold shield 4 extends into the liquid nitrogen tank 13 to maintain the cryogenic environment. The control unit communicates with the physical unit, controlling sample access operations through modular collaborative control.

[0028] The data acquisition module, serving as the starting module of the control device, periodically acquires analog signals from the temperature sensor fixing rod 34, image data from the bottom scanning device 11, and digital pulse signals from the position sensor via a digital interface. The data acquisition module performs cyclic redundancy checks on the raw data packets; if the check fails, a re-acquisition mechanism is triggered to ensure data integrity. The verified analog and digital pulse signals are smoothed using a Kalman filter algorithm to suppress random noise interference. The filtered temperature data, image-parsed identifier data, and position data are normalized using minimum and maximum scaling, respectively, mapping them to the zero-to-one range to ensure comparability of multi-source data. The normalized data, along with timestamps and data source identifiers, is encapsulated into a standardized data packet and output to the motion planning module, providing accurate input for motion planning.

[0029] The motion planning module receives standardized data packets from the data acquisition module, parses the target stored coordinates in the user commands, and accesses the pre-stored mesh mapping model of the aluminum disk assembly 3 to determine the precise position of the target aluminum tube 33. The motion planning module converts the coordinates of the target aluminum tube 33 into linear displacement commands for the linear motor 8 and rotation angle commands for the motion module 9 using an inverse kinematics model, establishing the kinematic relationship of the gripper assembly 10. Based on the temperature data fed back by the temperature sensor fixing rod 34, the motion planning module dynamically adjusts the weighting factors of the path planning, increasing the weight of paths in higher temperature areas to prioritize avoidance and reduce sample exposure risk. The motion planning module calls the historical motion error database, injecting transmission backlash compensation amounts associated with the motion direction into the linear displacement and rotation angle commands to compensate for gear transmission backlash errors. Using the A* search algorithm, the movement path of the gripper assembly 10 from its current position to the target aluminum tube 33 is calculated in the mesh mapping model, generating a pulse control sequence including pulse frequency and direction, which is output to the position calibration module to achieve optimized trajectory planning.

[0030] The position calibration module receives the pulse control sequence from the motion planning module and continuously acquires the real-time distance between the gripper assembly 10 and the target aluminum tube 33 via a laser rangefinder. Simultaneously, it collects acceleration and angular velocity data of the gripper assembly 10 via an inertial measurement unit. The position calibration module uses an extended Kalman filter algorithm to fuse the real-time distance and inertial measurement data, outputting an estimated value of the actual position of the gripper assembly 10 in three-dimensional space, thus improving position monitoring accuracy. The position calibration module calculates the Euclidean distance deviation between the estimated actual position and the theoretical trajectory coordinates of the motion planning module, and compares the deviation with a preset tolerance threshold, which is dynamically set according to the diameter of the aluminum tube 33. When the deviation exceeds the tolerance threshold, the position calibration module activates the PID controller, using the deviation value as input to calculate a correction amount for adjusting the frequency of the pulse control sequence, generating a correction signal including the correction amount and feeding it back to the motion planning module, forming a closed-loop control flow.

[0031] The execution control module receives the calibrated pulse control sequence from the position calibration module, parses the pulse control sequence into corresponding PWM waveform signals, and controls the operation of the linear motor 8 and the servo motor of the motion module 9 through micro-stepping drive technology. The micro-stepping subdivision is dynamically adjusted according to the calibration amount to achieve smooth motion control. When the gripper assembly 10 moves to a preset position above the target aluminum tube 33, the execution control module sends an opening command to the drive mechanism of the canister lid 15. After receiving a confirmation signal that the canister lid 15 is fully open, the execution control module controls the gripper assembly 10 to perform gripping and insertion actions at a preset current threshold corresponding to the sample tube material to avoid sample damage. After the gripper assembly 10 exits the liquid nitrogen tank 13, the execution control module delays for a predetermined time before sending a closing command to the drive mechanism of the canister lid 15 to ensure sealing. All modules are closely connected through data flow. The motion planning module updates the motion trajectory according to the calibration signal from the position calibration module. The actions of the execution control module and the calibration results coordinate in real time to achieve accurate positioning of sample storage and retrieval and stable maintenance of the low-temperature environment.

[0032] The motion planning module of this invention is configured to parse the target stored coordinates in the user command and access the pre-stored mesh mapping model of the aluminum disk assembly 3 to determine the precise position of the target aluminum tube 33. The mesh mapping model represents the storage space of the aluminum disk assembly 3 through three-dimensional mesh cells, with each cell associated with the coordinates of the aluminum tube 33. The spatial coordinates of the target aluminum tube 33 are converted into linear displacement commands of the linear motor 8 and rotation angle commands of the motion module 9 through the inverse kinematics model. The inverse kinematics establishes the coordinate system transformation relationship based on the principle of multi-joint kinematics. The weight factor of the path planning is dynamically adjusted according to the temperature data fed back by the temperature sensor fixing rod 34. The weight factor is positively correlated with the temperature value, and the weight is increased in higher temperature areas to guide path avoidance. The historical motion error database is called to inject the transmission backlash compensation amount. The compensation amount is calculated based on the motion direction and historical error curve to offset the gear transmission backlash. The A* search algorithm is used to calculate the movement path of the gripper assembly 10 from the current position to the target aluminum tube 33 in the mesh mapping model. The A* algorithm uses a heuristic function to evaluate the path cost and generate a pulse control sequence including pulse frequency and direction. The steps are sequentially connected, the target is located by parsing coordinates, kinematic transformation generates instructions, temperature weighting and gap compensation optimize path reliability, and path search achieves motion efficiency.

[0033] The position calibration module of this invention is configured to continuously acquire the real-time distance between the gripper assembly 10 and the target aluminum tube 33 via a laser rangefinder sensor, while simultaneously acquiring acceleration and angular velocity data of the gripper assembly 10 via an inertial measurement unit, with multi-sensor data acquisition occurring synchronously. An extended Kalman filter algorithm is used to fuse the real-time distance and inertial measurement data. The extended Kalman filter updates the estimated actual position of the gripper assembly 10 in three-dimensional space through state prediction and measurement updates. The Euclidean distance deviation between the estimated actual position and the theoretical trajectory coordinates of the motion planning module is calculated, based on spatial vector difference. The Euclidean distance deviation is compared with a preset tolerance threshold, which is dynamically set according to the diameter of the aluminum tube 33; the smaller the diameter, the stricter the threshold. When the deviation exceeds the tolerance threshold, the PID controller is activated. Using the deviation value as input, the PID controller calculates the output pulse frequency correction amount through proportional-integral-derivative calculations, generating a correction signal including the correction amount and feeding it back to the motion planning module. Sensor data fusion provides accurate position estimation, deviation comparison triggers the correction mechanism, and PID control achieves real-time error correction, forming a closed-loop feedback.

[0034] The execution control module of this invention is configured to receive a pulse control sequence containing a correction value from the position calibration module. The pulse sequence includes frequency adjustment parameters. The pulse control sequence is parsed into a corresponding PWM waveform signal, and the linear motor 8 and the servo motor of the motion module 9 are controlled using micro-stepping drive technology. The micro-stepping subdivision is dynamically adjusted according to the correction value; a higher subdivision value results in smoother movement. When the gripper assembly 10 moves to a preset position above the target aluminum tube 33, an opening command is sent to the drive mechanism of the canister lid 15. The preset position is based on a safety distance setting. After receiving a confirmation signal that the canister lid 15 is fully open, the gripper assembly 10 is controlled to perform gripping and insertion actions using a preset current threshold corresponding to the sample tube material. The current threshold is adjusted according to the sample tube hardness to avoid overload. After the gripper assembly 10 exits the liquid nitrogen tank 13, a closing command is sent to the canister lid 15 drive mechanism after a predetermined delay, allowing the sample to be completely detached. Pulse parsing drives the motor movement, the canister lid control and gripper action are synchronized, the current threshold protects sample integrity, and the delayed closing maintains the low-temperature environment.

[0035] The aluminum disk 31 of this invention is made of 6061-T6 aluminum alloy, which has high thermal conductivity and mechanical strength. A high-density aluminum tube mesh 35 is installed on the aluminum disk 31. The high-density aluminum tube mesh 35 physically isolates the samples through a grid structure, and the mesh aperture is adapted to the sample tube size. The high-density mesh design increases storage capacity, physical isolation reduces interference between samples, and the material properties ensure structural stability at low temperatures.

[0036] The Stirling loop siphon cold shield 4 of this invention includes a Stirling refrigerator 44, a siphon heat exchange chamber 41, a siphon 42, and a siphon vacuum sleeve 43. The Stirling refrigerator 44 cools the siphon heat exchange chamber 41, liquefying gaseous nitrogen; the cooling process is based on the Stirling cycle principle. The siphon 42 is located inside the siphon vacuum sleeve 43 and extends from the siphon heat exchange chamber 41 to the vicinity of the aluminum disk assembly 3 inside the liquid nitrogen tank 13, conducting cooling. The siphon vacuum sleeve 43 covers the outside of the siphon 42, fixing the siphon 42 and providing vacuum insulation; the vacuum layer reduces heat exchange. The refrigerator generates low temperature, the heat exchange chamber liquefies nitrogen, the siphon delivers cooling, and the vacuum sleeve provides insulation, working together to maintain the low-temperature environment.

[0037] The operation of the liquid nitrogen generator component 5 of this invention is managed by a control device, which is configured to continuously monitor the liquid level sensor data and the temperature data of the temperature sensor fixing rod 34 within the liquid nitrogen tank 13, with an adjustable monitoring frequency. A liquid nitrogen replenishment command is generated when the liquid level falls below a first threshold or the temperature exceeds a second threshold, the thresholds being set based on a safety range. The liquid nitrogen generator component 5 starts in response to the replenishment command, delivering the generated liquid nitrogen to the liquid nitrogen tank 13; the delivery pipeline is insulated. A stop command is generated when the liquid level reaches a third threshold and the temperature stabilizes within the target range, and the liquid nitrogen generator component 5 stops operating. Monitoring data triggers commands, automatically replenishing liquid nitrogen; threshold control ensures a stable liquid nitrogen level.

[0038] The data acquisition module of this invention is configured to periodically acquire analog signals from the temperature sensor fixing rod 34, image data from the bottom scanning device 11, and digital pulse signals from the position sensor via a digital interface. The interface protocol supports high-speed transmission. Cyclic redundancy check (CRC) is performed on the acquired raw data packets. If the check fails, a re-acquisition mechanism is triggered, and the checksum ensures data integrity. The verified analog and digital pulse signals are smoothed using a Kalman filter algorithm to suppress random noise. The Kalman filter outputs a stable value through recursive estimation. The filtered temperature data, image-parsed identifier data, and position data are normalized using minimum and maximum scaling, respectively, mapping them to the zero-to-one interval. Normalization ensures a unified scale for the multi-source data. The normalized data, along with the timestamp and data source identifier, is encapsulated into a standardized data packet and output to the motion planning module. Multi-source data acquisition, verification and filtering improve quality, normalization facilitates processing, and encapsulation ensures a consistent data stream structure.

[0039] The motion planning module of this invention dynamically adjusts the path planning weight factor based on temperature data. This is configured to establish a spatial temperature field model for the aluminum disk assembly 3. The temperature field model is constructed using multi-point temperature data collected by the temperature sensor fixing rod 34 array, and the storage space is divided into three-dimensional grid cells with temperature attribute values. An initial path weight factor is assigned to each three-dimensional grid cell. This initial path weight factor is positively correlated with the temperature attribute value of the grid cell. Grid cells with temperature attribute values ​​exceeding a first temperature threshold are marked as high-temperature avoidance zones, and their path weight factors are set to the maximum value. When calculating the movement path of the gripper assembly 10 from its current position to the target aluminum tube 33, the cost function of the A* search algorithm incorporates the path weight factor as a penalty term, causing the algorithm to prioritize paths traversing low-temperature grid cells. During the movement of the gripper assembly 10, the motion planning module continuously receives updated temperature data and dynamically refreshes the temperature field model and corresponding path weight factors accordingly. If a new high-temperature avoidance zone appears on the predetermined path of the gripper component 10, or if the temperature attribute value of an existing high-temperature avoidance zone continues to rise above the second temperature threshold, the motion planning module will interrupt the current path tracking and replan an optimized path that avoids all high-temperature avoidance zones based on the updated weight factors. The temperature field model reflects environmental changes in real time, the weight factors guide path selection, and dynamic replanning adapts to temperature fluctuations, ensuring sample safety.

[0040] This invention solves the problem of positioning deviation in biological sample storage and retrieval caused by insufficient precision in existing mechanical transmission and control systems by integrating a high-precision transmission mechanism and an intelligent control module. The cryogenic gas phase storage system includes physical devices and a control device. The control device consists of a data acquisition module, a motion planning module, a position calibration module, and an execution control module, forming a closed-loop control flow. The data acquisition module collects temperature data from the temperature sensor fixing rod 34, identification data from the bottom scanning device 11, and position data from the position sensor. It verifies and filters the raw signals, generating standardized data packets that are output to the motion planning module. The motion planning module parses the target storage coordinates in the user command, accesses the mesh mapping model of the aluminum disk assembly 3 to determine the position of the target aluminum tube 33, calculates the motion commands of the linear motor 8 and the motion module 9 through an inverse kinematics model, dynamically adjusts the path weight factor based on the temperature data, injects transmission clearance compensation by calling the historical motion error database, and generates an optimized pulse control sequence using a path search algorithm.

[0041] The position calibration module monitors the position of the gripper assembly 10 in real time using a laser rangefinder and an inertial measurement unit. It employs an extended Kalman filter algorithm to fuse multi-source data and outputs an estimated actual position, comparing the Euclidean distance deviation with the theoretical trajectory calculated by the motion planning module. When the deviation exceeds the tolerance threshold, the PID controller is activated to generate a pulse frequency correction, which is fed back to the motion planning module to update the motion trajectory. The execution control module receives the corrected pulse sequence, parses it into a PWM waveform signal, and controls the linear motor 8 and motion module 9 using micro-stepping drive technology. It also controls the gripper assembly 10's gripping action based on the sample tube material and a set current threshold, simultaneously synchronizing the opening and closing timing of the can lid 15. The feedback between the position calibration module and the motion planning module forms a closed-loop control, correcting motion trajectory deviations in real time and avoiding positioning errors during sample storage and retrieval. The high-density mesh 35 of the aluminum tube in the aluminum disk assembly 3 provides physical isolation to prevent cross-contamination between samples. The Stirling loop siphon cold shield 4 maintains a stable low-temperature environment by conducting cold energy through the siphon tube 42, reducing the impact of temperature fluctuations on sample activity. The entire system improves the accuracy and reliability of sample storage and retrieval through algorithm compensation and real-time monitoring.

[0042] Embodiment 1 of the present invention relates to an application scenario for precise control of the sample storage and retrieval process.

[0043] The user inputs the target sample tube coordinates through the human-machine interface. The data acquisition module initiates a multi-sensor data acquisition process. The temperature sensor fixing rod 34 array collects temperature data at multiple points inside the liquid nitrogen tank 13. The bottom scanning device 11 scans the sample tube barcode in the transport box 12, and the position encoder records the initial position of the gripper assembly 10. The collected raw data is processed by the Kalman filter algorithm to suppress noise, normalized, and encapsulated into standardized data packets for transmission to the motion planning module. The motion planning module parses the target coordinates, accesses the mesh mapping model of the aluminum disk assembly 3 to locate the target aluminum tube 33, calculates the linear displacement of the linear motor 8 and the rotation angle command of the motion module 9 through the inverse kinematics model, and dynamically adjusts the path weight factor based on the temperature data, increasing the path weight in higher temperature areas to guide avoidance. After injecting the transmission backlash compensation amount into the historical motion error database, the A-star search algorithm is used to generate an optimized pulse control sequence. The position calibration module monitors the position of the gripper assembly 10 in real time through the laser range sensor and the inertial measurement unit, expands the Kalman filter to fuse multi-source data, outputs the actual position estimate, and compares the Euclidean distance deviation with the theoretical trajectory. When the deviation exceeds the tolerance threshold set according to the diameter of the aluminum tube 33, the PID controller generates a pulse frequency correction value and feeds it back to the motion planning module to update the trajectory. The execution control module parses the corrected pulse sequence into a PWM waveform signal and controls the motor to operate through micro-stepping drive technology. When the gripper assembly 10 moves to the target position, it triggers the can lid 15 to open, and performs the gripping action with a current threshold matched to the sample tube material. After the storage and retrieval are completed, the can lid 15 is closed with a delay. The entire system process corrects the trajectory deviation in real time through closed-loop control, achieving sub-millimeter positioning accuracy for sample storage and retrieval.

[0044] Embodiment 2 of the present invention relates to an application scenario for maintaining stable operation in a low-temperature environment.

[0045] The Stirling refrigerator 44 of the Stirling loop siphon cooling shield 4 cools the siphon heat exchange chamber 41, liquefying gaseous nitrogen within the chamber. The liquefied nitrogen is then transported through the siphon 42, under the vacuum insulation protection of the siphon vacuum sleeve 43, to the vicinity of the aluminum disc assembly 3 inside the liquid nitrogen tank 13, maintaining the storage area temperature stable below -150 degrees Celsius. The operation of the liquid nitrogen generator assembly 5 is intelligently managed by a control device. The data acquisition module continuously monitors the liquid level sensor data and the temperature data of the temperature sensor fixing rod 34 inside the liquid nitrogen tank 13. When the liquid level is below the first threshold or the temperature is above the second threshold, a liquid nitrogen replenishment command is generated. The liquid nitrogen generator assembly 5 starts and delivers the generated liquid nitrogen to the liquid nitrogen tank 13 through an insulated pipeline. When the liquid level reaches the third threshold and the temperature stabilizes within the target range, the system generates a stop command to terminate the replenishment process. The aluminum disk assembly 3 is made of 6061-T6 aluminum alloy. A high-density mesh 35 of aluminum tubes forms a physical isolation grid on the surface of the aluminum disk 31. The mesh aperture is designed according to the standard sample tube size to prevent contact and collision between sample tubes. Temperature sensor fixing rods 34 are arrayed to monitor the temperature of each area in real time. The data is fed back to the motion planning module to dynamically adjust the path weights, preventing the gripper assembly 10 from traversing high-temperature areas. The entire system, through the coordinated operation of Stirling cooling and intelligent liquid replenishment, reduces liquid nitrogen consumption to less than 20% of existing equipment, while ensuring that the temperature fluctuation of the storage environment does not exceed ±3 degrees Celsius.

Claims

1. A cryogenic vapor phase storage system, characterized in that, It includes a physical device and a control device, wherein the control device is communicatively connected to the physical device and is used to control the physical device to perform sample storage and retrieval. The physical device includes an upper compartment (1), a liquid nitrogen tank assembly (2), an aluminum disc assembly (3), a Stirling loop siphon cold screen (4), a liquid nitrogen generator assembly (5), and an outer frame (6). The liquid nitrogen tank assembly (2) and the liquid nitrogen generator assembly (5) are installed inside the outer frame (6), and the outer frame (6) is connected to the Stirling loop siphon cold screen (4). The upper compartment (1) is located on the upper part of the outer frame (6). The upper compartment (1) is equipped with a linear motor (8) and a motion module (9). The motion module (9) is connected to a gripper assembly (10). The bottom of the upper compartment (1) is equipped with a bottom sweeping device (11). The liquid nitrogen tank assembly (2) is equipped with a tank cover (15) on top. A large gear ring (7) is fixed on the surface of the tank cover (15) of the liquid nitrogen tank assembly (2), which meshes with a small gear (14) located in the upper compartment (1). The aluminum disk assembly (3) is housed inside the liquid nitrogen tank (13) of the liquid nitrogen tank assembly (2). The aluminum disk assembly (3) includes an aluminum disk (31), a central support rod (32), an aluminum tube (33), a temperature sensor fixing rod (34), and a high-density mesh of aluminum tubes (35). The aluminum disk (31) is installed on the top of the central support rod (32), and the aluminum tube (33) and the temperature sensor fixing rod (34) are installed on the bottom of the aluminum disk (31). The Stirling loop siphon cold shield (4) extends into the interior of the liquid nitrogen tank (13); The control device includes: The data acquisition module is used to collect temperature data from the temperature sensor fixing rod (34), the identification data of the bottom scanning device (11), and the position data of the position sensor; The motion planning module is used to receive data from the data acquisition module and calculate the motion trajectory of the gripper component (10); The position calibration module is used to receive the motion trajectory data of the motion planning module and generate a correction signal based on the real-time monitored position deviation of the gripper component (10); The execution control module is used to receive the corrected trajectory data from the position calibration module, drive the linear motor (8) and the motion module (9) to move, and control the action of the gripper assembly (10); The position calibration module sends the correction signal to the motion planning module, which updates the motion trajectory based on the correction signal to form a closed-loop control.

2. The cryogenic vapor phase storage system according to claim 1, characterized in that, The motion planning module is configured as follows: Parse the target storage coordinates in the user instruction and access the pre-stored aluminum disk assembly (3) mesh mapping model to determine the precise location of the target aluminum tube (33); By using the inverse kinematics model, the coordinates of the target aluminum tube (33) are converted into the linear displacement command of the linear motor (8) and the rotation angle command of the motion module (9); The weight factor of the path planning is dynamically adjusted based on the temperature data fed back by the temperature sensor fixing rod (34), wherein the path weight of the higher temperature area is increased to prioritize avoidance; The historical motion error database is invoked to inject a transmission backlash compensation amount associated with the motion direction into the linear displacement command and the rotation angle command; The A* search algorithm is used to calculate the movement path of the gripper component (10) from its current position to the target aluminum tube (33) in the grid mapping model, and a pulse control sequence including pulse frequency and direction is generated and output to the position calibration module.

3. The cryogenic vapor phase storage system according to claim 2, characterized in that, The position calibration module is configured to: The real-time distance between the gripper assembly (10) and the target aluminum tube (33) is continuously acquired by the laser rangefinder, and the acceleration and angular velocity data of the gripper assembly (10) are collected by the inertial measurement unit. The extended Kalman filter algorithm is used to fuse the real-time distance and inertial measurement data to output the estimated actual position of the gripper component (10) in three-dimensional space; Calculate the Euclidean distance deviation between the actual position estimate and the theoretical trajectory coordinates from the motion planning module; The Euclidean distance deviation is compared with a preset tolerance threshold, which is dynamically set according to the diameter of the aluminum tube (33); When the deviation exceeds the tolerance threshold, the PID controller is activated, the deviation value is used as input, a correction amount for adjusting the frequency of the pulse control sequence is calculated, and a correction signal including the correction amount is generated and fed back to the motion planning module.

4. The cryogenic vapor storage system according to claim 3, characterized in that, The execution control module is configured as follows: Receive a pulse control sequence containing the correction amount from the position calibration module; The pulse control sequence is parsed into the corresponding PWM waveform signal, and the linear motor (8) and the servo motor of the motion module (9) are controlled by micro-stepping drive technology, wherein the micro-stepping subdivision is dynamically adjusted according to the correction amount; When the gripper assembly (10) moves to a preset position above the target aluminum tube (33), an opening command is sent to the drive mechanism of the can lid (15); After receiving a confirmation signal that the can lid (15) is fully open, the gripper assembly (10) is controlled to perform gripping and insertion actions with a preset current threshold corresponding to the sample tube material. After the gripper assembly (10) exits the liquid nitrogen tank (13), a closing command is sent to the tank cover (15) drive mechanism after a predetermined time delay.

5. The cryogenic vapor phase storage system according to claim 4, characterized in that, The aluminum disk (31) is made of 6061-T6 aluminum alloy material, and a high-density aluminum tube mesh (35) is provided on the aluminum disk (31) for physical isolation of the sample.

6. The cryogenic vapor phase storage system according to claim 5, characterized in that, The Stirling loop siphon cold shield (4) includes a Stirling refrigerator (44), a siphon heat exchange chamber (41), a siphon (42), and a siphon vacuum sleeve (43). The Stirling refrigerator (44) cools the siphon heat exchange chamber (41) to liquefy gaseous nitrogen; The siphon tube (42) is located inside the siphon tube vacuum sleeve (43) and extends from the siphon tube heat exchange chamber (41) to the vicinity of the aluminum disk assembly (3) inside the liquid nitrogen tank (13); The siphon vacuum sleeve (43) covers the outside of the siphon (42) and is used to fix the siphon (42) and provide vacuum insulation.

7. The cryogenic vapor storage system according to claim 6, characterized in that, The operation of the liquid nitrogen generator assembly (5) is managed by the control device, which is configured to: Continuously monitor the liquid level sensor data and the temperature data of the temperature sensor fixing rod (34) in the liquid nitrogen tank (13); When the liquid level is lower than the first threshold or the temperature is higher than the second threshold, a liquid nitrogen replenishment command is generated. The liquid nitrogen generator assembly (5) is activated in response to the liquid nitrogen replenishment command and delivers the generated liquid nitrogen to the liquid nitrogen tank (13). When the liquid level reaches the third threshold and the temperature stabilizes within the target range, a stop command is generated, and the liquid nitrogen generator assembly (5) stops working.

8. The cryogenic vapor phase storage system according to claim 7, characterized in that, The data acquisition module is configured as follows: The analog signals of the temperature sensor fixing rod (34), the image data of the bottom scanning device (11), and the digital pulse signals of the position sensor are periodically collected through the digital interface. Cyclic redundancy check is performed on the collected raw data packets. If the check fails, a re-collection mechanism is triggered. The analog and digital pulse signals that pass the verification are smoothed using a Kalman filter algorithm to suppress random noise. The filtered temperature data, image-parsed identification data, and location data are normalized using minimum and maximum scaling respectively, and mapped to the [0, 1] interval. The normalized data, along with the timestamp and data source identifier, is encapsulated into a standardized data packet and output to the motion planning module.

9. The cryogenic vapor phase storage system according to claim 8, characterized in that, The operation of dynamically adjusting the path planning weight factors based on temperature data in the motion planning module is configured to be executed: A spatial temperature field model of the aluminum disk assembly (3) is established. The temperature field model is constructed by collecting multi-point temperature data from the array of temperature sensor fixing rods (34), and the storage space is divided into three-dimensional grid units with temperature attribute values. An initial path weight factor is assigned to each of the three-dimensional mesh cells. The initial path weight factor is positively correlated with the temperature attribute value of the mesh cell. Mesh cells with temperature attribute values ​​exceeding a first temperature threshold are marked as high-temperature avoidance zones, and their path weight factors are set to the maximum value. When calculating the moving path of the gripper assembly (10) from its current position to the target aluminum tube (33), the path weight factor is introduced as a penalty term in the cost function of the A* search algorithm, so that the algorithm preferentially selects the path that traverses the low-temperature grid cell; During the movement of the gripper assembly (10), the motion planning module continuously receives updated temperature data and dynamically refreshes the temperature field model and the corresponding path weight factor accordingly. If a new high-temperature avoidance zone appears on the predetermined path of the gripper component (10), or the temperature attribute value of the existing high-temperature avoidance zone continues to rise above the second temperature threshold, the motion planning module interrupts the current path tracking and replans an optimized path that avoids all high-temperature avoidance zones based on the refreshed weight factor, and sends the updated pulse control sequence to the position calibration module.

10. A control method for a cryogenic vapor phase storage system, applied to the cryogenic vapor phase storage system as described in any one of claims 1 to 9, characterized in that, include: Step 1: Periodically collect the temperature analog signal from the temperature sensor fixing rod (34), the image data from the bottom scanning device (11), and the digital pulse signal from the position sensor through the data acquisition module; verify the collected raw data packets, apply a filtering algorithm to smooth the verified analog signal and digital pulse signal, and normalize the processed multi-source data to generate standardized data packets; Step 2: The motion planning module receives the standardized data packet, parses the target stored coordinates in the user command and accesses the pre-stored aluminum disk assembly (3) mesh mapping model to determine the position of the target aluminum tube (33); the target coordinates are converted into linear displacement commands of the linear motor (8) and rotation angle commands of the motion module (9) through the inverse kinematics model; the weight factor of the path planning is dynamically adjusted according to the temperature data, the transmission clearance compensation amount is injected by calling the historical motion error database, the path search algorithm is used to calculate the movement path of the gripper assembly (10) from the current position to the target aluminum tube (33), and a pulse control sequence is generated. Step 3: The position calibration module obtains the actual position estimate of the gripper component (10) through multi-sensor fusion processing, calculates the Euclidean distance deviation between it and the theoretical trajectory of the motion planning module; when the deviation exceeds the tolerance threshold dynamically set according to the diameter of the aluminum tube (33), the PID controller generates a pulse frequency correction amount, and feeds back the correction signal including the correction amount to the motion planning module to update the motion trajectory. Step 4: The execution control module receives the corrected pulse control sequence, parses it into a PWM waveform signal, and controls the linear motor (8) and motion module (9) to operate through micro-stepping drive technology; when the gripper assembly (10) moves to a preset position above the target aluminum tube (33), the can lid (15) opening command is triggered; after confirming that the can lid is fully open, the gripper assembly (10) is controlled to perform gripping and insertion actions with a current threshold corresponding to the sample tube material, and the can lid closing command is triggered after a predetermined delay after exiting the liquid nitrogen tank (13); In this process, a closed-loop feedback control is formed between steps 2 and 3. The execution action of step 4 is coordinated with the calibration result of step 3 in real time to jointly achieve the positioning and temperature stability control of sample storage and retrieval.

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