Mechanical arm auxiliary positioning system and positioning method based on CT bed linkage control

Abstract

The invention provides a mechanical arm auxiliary positioning system and method based on CT bed linkage control. The system comprises a CT machine host, a CT bed, a telescopic support, a mechanical arm assembly and a linkage control module. The CT bed is provided with a bed position detection sensor so as to obtain motion parameters of the CT bed in translation, lifting and inclination directions in real time; the telescopic bracket is arranged on a shell of the CT machine host; the mechanical arm assembly is arranged at the moving end of the telescopic support. The linkage control module is in communication connection with the bed position detection sensor, the CT machine host and the mechanical arm assembly, CT bed motion parameters serve as an active change source, a spatial mapping relation among a CT image coordinate system, a CT bed coordinate system and a mechanical arm base coordinate system is established, mechanical arm reference coordinates are updated in real time when the position of a CT bed changes, and the mechanical arm base coordinate system is updated in real time when the position of the CT bed changes. And dynamic compensation control is performed on the pose of the mechanical arm, so that the position of the tail end of the mechanical arm relative to the target area of the patient is kept constant, and the operation safety and reliability are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, and particularly relates to a mechanical arm assisted positioning system and positioning method based on CT bed linkage control. BACKGROUND

[0002] In medical image guided interventional operations, CT guided puncture, biopsy, ablation and related positioning operations are widely used in chest, abdomen and other clinical scenarios. The existing CT guided interventional operation is usually completed by a doctor through manual operation at the side of the CT bed according to the CT image results to complete the puncture positioning and needle insertion operation.

[0003] To improve positioning accuracy and reduce the operation burden of doctors, some existing technologies introduce a mechanical arm or an auxiliary positioning device into the CT guided interventional operation, and perform puncture guidance, needle fixation or patient limb auxiliary fixation through the mechanical arm. However, the existing CT guided mechanical arm system is designed on the premise that the CT bed is in a stationary state, and the positioning control of the mechanical arm usually depends on the initial image registration result.

[0004] In actual clinical operation process, the CT bed often needs to be translated, lifted or adjusted in angle for multiple times in the scanning and operation stages to meet different scanning layers and operation requirements. Since the position change of the CT bed cannot be effectively linked with the mechanical arm control system, when the CT bed moves, the position relationship of the mechanical arm end relative to the target region of the patient is easy to deviate, and then the positioning accuracy is affected, and the operation burden of repeated scanning or manual correction is increased.

[0005] In addition, the CT scanning process has strict safety and timing requirements for the running state of the equipment. The existing mechanical arm assisted system usually does not establish an effective interlocking control mechanism with the CT scanning state, and it is difficult to automatically manage the mechanical arm movement in the scanning process, thereby to a certain extent, limiting the application reliability and safety of the system in the clinical environment.

[0006] Therefore, it is urgent to provide a mechanical arm assisted positioning system and positioning method based on CT bed linkage control, which can realize dynamic linkage control between the CT bed and the mechanical arm in the CT guided interventional operation, so as to keep the position of the mechanical arm end relative to the target region of the patient stable, and improve the operation safety and reliability. SUMMARY

[0007] The present application aims to provide a mechanical arm assisted positioning system and positioning method based on CT bed linkage control, which aims to solve the technical problems that the mechanical arm end is difficult to keep the position relative to the target region of the patient stable and lacks scanning state linkage control in the CT bed movement process.

[0008] To achieve the above objectives, in a first aspect, the present invention provides a robotic arm-assisted positioning system based on CT bed linkage control, comprising:

[0009] The CT scanner main unit is used to acquire the patient's CT image data and output scan status signals;

[0010] A CT bed includes a CT bed body and a bed position detection sensor disposed on the CT bed body, for real-time detection of the CT bed's motion state in at least translational, lifting and tilting directions;

[0011] A telescopic bracket is installed on the outer shell of the CT machine main unit. The telescopic bracket is arranged in a direction parallel to the long axis of the CT bed, and its telescopic stroke covers the effective operating area of ​​the CT bed.

[0012] At least one robotic arm assembly is disposed at the movable end of the retractable support;

[0013] The linkage control module is communicatively connected to the bed position detection sensor, the CT scanner main unit, and the robotic arm assembly, respectively; the linkage control module is configured as follows:

[0014] Establish the spatial mapping relationship between the CT image coordinate system, the CT bed coordinate system, and the robotic arm base coordinate system;

[0015] Using the real-time motion parameters of the CT bed as input, the pose compensation amount of the robotic arm end effector is calculated through coordinate transformation; the robotic arm is dynamically controlled according to the pose compensation amount to keep the robotic arm end effector in a constant position relative to the patient's target area.

[0016] As a further improvement to the above solution, the robotic arm assembly has no less than six degrees of freedom, and its end is detachably equipped with a puncture guide, a needle fixator, or a patient fixation device.

[0017] As a further improvement to the above solution, the linkage control module includes:

[0018] The bed monitoring unit is used to collect the displacement and angle parameters of the CT bed and form a motion parameter matrix;

[0019] The coordinate mapping unit calculates the equivalent inverse compensation amount of the robot arm pose based on the motion parameter matrix;

[0020] The path planning unit generates the robotic arm's motion path based on CT image data;

[0021] The safety interlock unit controls the state of the robotic arm when it is in scanning mode or when parameters exceed limits.

[0022] As a further improvement to the above scheme, the bed monitoring unit is used to collect the displacement parameters of the CT bed in three orthogonal directions and the angle parameters around at least one axis in real time, and form a bed motion parameter matrix.

[0023] As a further improvement to the above scheme, the coordinate mapping unit calculates the compensation amount using the following formula:

[0024] Δθ = J + (θ) × ΔX;

[0025] Where Δθ is the joint angle compensation amount, J + (θ) is the pseudo-inverse of the Jacobian matrix of the robotic arm, and ΔX is the change in bed motion.

[0026] As a further improvement to the above solution, the path planning unit identifies the target area based on CT image data and generates a motion path for the robotic arm to perform puncture positioning or patient fixation operations.

[0027] As a further improvement to the above solution, the safety interlock unit is configured to: control the robotic arm assembly to pause movement when the CT scanner host is detected to be in scanning mode;

[0028] Alternatively, when the motion parameters of the CT bed are detected to exceed a preset safety threshold, the robotic arm assembly can be locked.

[0029] Secondly, the present invention also provides a robotic arm-assisted positioning method based on CT bed linkage control, applied to the system described in the first aspect, the steps of which include:

[0030] S1. Acquire the initial position information of the CT bed and establish the CT bed coordinate system;

[0031] S2. Spatial registration is performed between the CT image coordinate system and the robotic arm base coordinate system to obtain the coordinate transformation relationship;

[0032] S3. Real-time acquisition of CT bed motion parameters;

[0033] S4. Using the motion parameters of the CT bed as the active source of change, the reference coordinates of the robotic arm are updated in real time through rigid body transformation calculation.

[0034] S5. Based on CT image data, plan the motion path and combine dynamic compensation to control the positioning operation of the robotic arm.

[0035] As a further improvement to the above scheme, the spatial registration adopts the following steps:

[0036] S21. Place imaging markers on the CT bed and obtain image coordinates through CT scanning;

[0037] S22. Obtain the corresponding coordinates in the robotic arm coordinate system through robotic arm contact measurement;

[0038] S23. Use the ICP algorithm to calculate the rigid body transformation matrix between coordinate systems.

[0039] As a further improvement to the above scheme, the dynamic compensation adopts closed-loop control, and the specific method is as follows:

[0040] S51. Real-time acquisition of robotic arm position feedback signals;

[0041] S52. Compare the deviation between the actual position and the target position;

[0042] S53. The robot arm motion is corrected in real time using a PID algorithm.

[0043] As a further improvement to the above scheme, the movement of the robotic arm is paused during the activation of the CT scan signal, and the image registration is re-performed and the automatic control of the robotic arm is resumed after the scan is completed.

[0044] Because the present invention adopts the above technical solutions, the beneficial effects of this application are as follows:

[0045] 1. The present invention provides a robotic arm-assisted positioning system based on CT bed linkage control. First, by setting a bed position detection sensor on the CT bed, and using the motion parameters of the CT bed as the active change source for robotic arm control, when the CT bed undergoes translation, lifting, or tilting changes, the linkage control module can update the reference coordinates of the robotic arm in real time and dynamically compensate its posture, thereby keeping the position of the robotic arm end relative to the patient's target area stable and reducing positioning deviations caused by bed movement.

[0046] Secondly, since a spatial mapping relationship is established between the CT image coordinate system, the CT bed coordinate system and the robotic arm base coordinate system, when the position of the CT bed changes, there is no need to manually reposition or repeat the registration, which helps to reduce operation steps and improve the continuity of the CT-guided assisted positioning process.

[0047] Furthermore, the linkage control module communicates with the CT scanner host to obtain scanning status signals, enabling the motion control of the robotic arm to coordinate with the CT scanning process. This avoids unnecessary robotic arm movements during the scanning process and reduces the potential impact on image acquisition and patient safety.

[0048] In addition, by setting the robotic arm at the distal end of a retractable bracket mounted on the CT machine's main housing, and ensuring that the bracket's extension stroke covers the effective operating area of ​​the CT bed, this invention can adapt to different bed positions and operating area requirements, facilitating integration with existing CT equipment.

[0049] Through the synergistic combination of the above-mentioned technical features, the present invention can maintain the relative positional relationship between the end effector of the robotic arm and the target area of ​​the patient under CT bed motion conditions, which is beneficial to improving the reliability of CT-guided robotic arm-assisted positioning operations.

[0050] 2. This invention provides a robotic arm-assisted positioning method based on CT bed linkage control. It establishes a CT bed coordinate system to provide a quantitative benchmark for linkage control. By registering the CT image coordinate system with the robotic arm base coordinate system, it achieves accurate mapping between the image space and the operating space. Real-time acquired CT bed motion parameters are used as compensation input, enabling the robotic arm to use it as an active source of change, dynamically updating the reference coordinates and compensating for pose in real time. This suppresses positioning drift during CT bed movement and maintains a constant position of the end effector relative to the patient's target area. Furthermore, by combining path planning based on CT image data with continuous compensation during execution, it achieves linkage control between robotic arm movement and scanning status. The synergistic effect of these technical features forms a closed-loop control chain from benchmark establishment, spatial registration, real-time detection to dynamic compensation and path execution. This maintains positioning stability and accuracy throughout the scanning cycle, effectively solving the problems of the robotic arm's end effector being easily disturbed by bed movement and lack of scanning linkage, thus improving the reliability and clinical applicability of positioning operations. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0052] Figure 1 This is a front view schematic diagram of a robotic arm-assisted positioning system based on CT bed linkage control disclosed in this invention;

[0053] Figure 2 This is a flowchart illustrating a robotic arm-assisted positioning method based on CT bed linkage control disclosed in this invention.

[0054] Figure label:

[0055] 1. CT scanner main unit; 2. CT bed; 3. Fixation device; 4. Telescopic support; 5. First robotic arm; 6. Second robotic arm.

[0056] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0057] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0058] It should be noted that all directional indicators (such as up, down, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of the components in a specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0059] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0060] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0061] Example 1

[0062] See Figure 1 This invention provides a robotic arm-assisted positioning system based on the linkage control of a CT bed 2, used to achieve dynamic linkage control between the robotic arm and the CT bed 2 during CT guided operations. The system includes a CT scanner main unit 1, a CT bed 2, a retractable support 4, a robotic arm assembly, and a linkage control module.

[0063] Specifically, the CT scanner host 1 is used to acquire the patient's CT image data and output a scan status signal during the scanning process. By introducing the scan status signal, the system can manage the movement of the robotic arm during subsequent control, which helps to ensure the stability of the image acquisition process.

[0064] The CT bed 2 includes a CT bed 2 body and a bed position detection sensor mounted on the bed body. The bed position detection sensor (not shown in the drawing) is embedded in the CT bed 2 body, and its detection signal is transmitted to the linkage control module via wired / wireless means. The bed position detection sensor is used to detect the motion state of the CT bed 2 in the translational, lifting, and tilting directions in real time, and outputs the corresponding bed motion parameters. Real-time acquisition of the bed's motion state provides basic data for subsequent robotic arm linkage control.

[0065] The retractable support 4 is mounted on the outer casing of the CT scanner main unit 1 via the fixing device 3 and is arranged parallel to the long axis of the CT bed 2. Its extension stroke covers the effective operating area of ​​the CT bed 2. Through the above structural design, the working range of the robotic arm can be adjusted according to the position of the CT bed 2, which is beneficial for adapting to the operational needs of different bed positions.

[0066] At least one robotic arm assembly is disposed at the movable end of the retractable support 4. The robotic arm assembly has multiple degrees of freedom, and its end can be fitted with a puncture guide, needle holder, or patient fixation device for performing assisted positioning operations. The robotic arm assembly is communicatively connected to a linkage control module via a control interface. In this embodiment, two robotic arms are provided at the movable end of the retractable support 4, namely a first robotic arm 5 and a second robotic arm 6. The first robotic arm 5 is used to install the puncture guide, and the second robotic arm 6 is used to install the patient fixation device.

[0067] The linkage control module is communicatively connected to the bed position detection sensor, the CT scanner main unit 1, and the robotic arm assembly. The linkage control module uses the motion parameters of the CT bed 2 as the active source of change to establish a spatial mapping relationship between the CT image coordinate system, the CT bed 2 coordinate system, and the robotic arm base coordinate system. In the initial state of the system, the correspondence between each coordinate system is determined through image registration or calibration.

[0068] When the CT bed 2 undergoes translation, elevation, or tilting changes, the linkage control module updates the reference coordinates of the robotic arm based on real-time acquired bed motion parameters and performs dynamic compensation control on the robotic arm's pose. This configuration ensures that the robotic arm's end effector maintains a relatively constant position relative to the patient's target area during CT bed 2 movement, thereby reducing the impact of bed movement on assisted positioning accuracy. During CT scanning, the linkage control module, in conjunction with the scanning status signal output from the CT scanner host 1, manages the robotic arm's movement accordingly to avoid unnecessary robotic arm movements during the scanning phase, thus improving the system's safety and reliability. Through the above structure and control process, this embodiment can achieve linkage compensation control of the robotic arm under CT bed 2 movement conditions, keeping the robotic arm's end effector's position relative to the patient's target area stable, making it suitable for CT-guided assisted positioning operations.

[0069] In a preferred embodiment, the robotic arm assembly has at least six degrees of freedom. By setting multiple degrees of freedom, the robotic arm can adjust the spatial position and posture of the end effector accordingly when the CT bed 2 and the patient's position change, thereby cooperating with the linkage control module to achieve pose compensation control, which is beneficial to maintaining the stability of the positional relationship between the robotic arm end effector and the patient's target area during the movement of the CT bed 2.

[0070] The robotic arm assembly has a detachable mounting interface at its end for mounting end effectors such as puncture guides, needle holders, or patient fixation devices. This detachable connection allows the robotic arm end effector to be replaced according to specific operational needs, enabling the same robotic arm assembly to be used for different auxiliary operations such as puncture positioning, needle stabilization, or patient limb fixation, thus improving the system's applicability in various CT-guided scenarios.

[0071] In practical applications, after acquiring the motion parameters of the CT bed 2, the linkage control module coordinates the joints of the robotic arm, causing the puncture guide or fixation device 3 installed at the end to make corresponding compensation adjustments as the bed moves. Through this structure and control method, the impact of bed adjustments or changes in patient position on the positioning status of the robotic arm's end effector can be reduced, thus improving the stability of assisted positioning operations.

[0072] It should be noted that the number of degrees of freedom of the robotic arm and the specific form of the end effector can be appropriately adjusted according to actual application requirements. Without departing from the technical concept of this invention, they should all be considered within the scope of protection of this invention.

[0073] In a preferred embodiment, the linkage control module includes a bed monitoring unit, a coordinate mapping unit, a path planning unit, a safety interlock unit, and an execution control unit. Each unit works in concert to achieve linkage control between the CT bed 2 and the robotic arm.

[0074] The bed monitoring unit is connected to the drive system of the CT bed 2 and collects in real time the translational displacement parameters (e.g., bed surface advance / retreat, rise / fall, and lateral movement) of the CT bed 2 in the three orthogonal directions of X, Y, and Z, as well as the angular parameters around at least one axis (e.g., bed surface pitch or rotation axis). These parameters are updated synchronously according to the sampling period and organized by the bed monitoring unit into a bed motion parameter matrix P(t). By continuously acquiring P(t), the spatial pose changes of the CT bed 2 at any given moment can be captured comprehensively, providing detailed data support for subsequent accurate compensation and avoiding positioning drift caused by missed angular deviations.

[0075] The coordinate mapping unit receives the bed motion parameter matrix P(t) and, in conjunction with the initial calibration relationship between the robotic arm base coordinate system and the CT bed 2 coordinate system, performs equivalent inverse compensation calculations on the current pose of the robotic arm's end effector. The coordinate mapping unit calculates the compensation amount using the following formula:

[0076] Δθ = J + (θ) × ΔX;

[0077] Where Δθ is the joint angle compensation amount, J + (θ) represents the pseudo-inverse of the Jacobian matrix of the robotic arm, and ΔX represents the change in bed position motion. Specifically, when the CT bed 2 undergoes displacement or angular change, the coordinate mapping unit calculates the compensation amount to be added to each joint of the robotic arm or the correction command for the end effector pose based on this change, so that the relative position of the robotic arm end effector relative to the patient's target area remains stable. By equivalently converting the bed motion into the robotic arm pose correction amount, the robotic arm can maintain the relative positional relationship between the end effector and the patient's target area during bed position changes, thereby reducing the positioning deviation caused by bed movement.

[0078] The coordinate mapping unit establishes the mapping relationship between various coordinate systems through rigid body transformation. The transformation matrix T includes a 3×3 rotation matrix R and a 3×1 translation vector t. The rotation matrix R is calculated by Euler transformation of the CT bed's pitch angle α, yaw angle β, and roll angle γ, while the translation vector t is determined by the displacement parameters collected in real time by the bed position detection sensor. This rigid body transformation ensures that the positional relationship of the robotic arm's end effector relative to the patient's target area remains constant during the CT bed's movement.

[0079] The path planning unit receives CT image data and uses image recognition algorithms to automatically or semi-automatically identify target areas (such as lesions or puncture points). Based on surgical or examination requirements, it generates a motion path for the robotic arm to perform puncture positioning or patient immobilization. The path planning unit sends the generated path information to the execution control unit, which, based on this path and in conjunction with real-time compensation data from the coordinate mapping unit, drives the robotic arm to complete smooth and accurate movements. Thus, precise positioning of specific targets can be achieved while ensuring end-effector stability.

[0080] The safety interlock unit communicates with the CT scanner main unit 1, the bed monitoring unit, and the robotic arm controller. Firstly, when the safety interlock unit detects that the CT scanner main unit 1 has entered scanning mode, it immediately sends a pause command to the execution control unit, causing the robotic arm assembly to stop moving, preventing mechanical vibration or radiation interference during the scanning process from affecting image quality and equipment safety. Secondly, when the motion parameters of the CT bed 2 reported by the bed monitoring unit exceed a preset safety threshold (such as excessive displacement speed or angle exceeding limits), the safety interlock unit controls the robotic arm assembly to enter a locked state, avoiding the risk of collision between the robotic arm and the patient or equipment caused by abnormal bed movement. This interlock mechanism can significantly improve the reliability and safety of the system in dynamic environments, reducing the probability of misoperation and accidents.

[0081] During operation, the bed monitoring unit continuously collects P(t) and transmits it to the coordinate mapping unit and the safety interlock unit; the coordinate mapping unit outputs the compensated pose command to the execution control unit; the path planning unit generates a path based on the image data and coordinates with the compensation command to guide the movement of the robotic arm; the safety interlock unit monitors the scanning status and bed parameters in real time and intervenes to control the system in case of abnormalities to ensure safety and positioning accuracy throughout the process.

[0082] In a preferred embodiment, the execution control unit, as the core driving component of the linkage control module, establishes data interaction channels with the coordinate mapping unit, path planning unit, and safety interlock unit, respectively. At the same time, it is directly connected to the servo drive system, joint encoder, limit switch, and other hardware of the robotic arm component. It is responsible for converting the compensated pose command and planned path into the actual movement of the robotic arm and ensuring the smoothness and controllability of the movement process.

[0083] In this embodiment, the execution control unit includes a motion calculation module, a trajectory tracking module, and a dynamic feedback adjustment module.

[0084] The motion calculation module receives equivalent inverse compensation pose data (including position and attitude corrections) from the coordinate mapping unit and the target path point sequence output by the path planning unit. Based on the robotic arm's kinematic model (such as forward / inverse kinematic equations), it performs real-time calculations to generate target angle or displacement command sequences for each joint. By fusing the compensation data with the path points, it ensures that the robotic arm's end effector moves along a predetermined trajectory while simultaneously offsetting the relative position drift caused by the movement of the CT bed 2 during puncture positioning or fixation operations. This method improves the repeatability and stability of end-effector positioning and reduces secondary adjustments caused by bed movement.

[0085] The trajectory tracking module generates continuous control signals based on the calculated joint command sequence and a pre-defined velocity curve (such as a trapezoidal or S-shaped acceleration / deceleration curve), and sends these signals to the robotic arm servo driver. This module has a built-in trajectory look-ahead function, which can predict changes in path curvature and optimize acceleration distribution in advance, thereby avoiding mechanical vibrations or patient discomfort caused by sudden motion changes. Simultaneously, through closed-loop feedback comparison with the joint encoder, it corrects the deviation between the actual position and the target position in real time, improving tracking accuracy.

[0086] The dynamic feedback adjustment module continuously collects the actual pose and velocity information of each joint of the robotic arm during movement and compares it with the theoretical values ​​given by the motion calculation module. It then dynamically adjusts the control based on proportional-integral-derivative (PID) or other advanced control algorithms to address any errors. When the safety interlock unit issues a pause or lock command, this module can immediately cut off or limit the drive output, allowing the robotic arm to quickly enter a safe state. This design can shorten response time in emergency situations and reduce the risk of impact on patients and equipment.

[0087] The execution control unit can not only accurately execute the path instructions for fusion compensation, ensuring the stability of the robotic arm end position relative to the patient's target area, but also has good smoothness and anti-disturbance ability during movement; in conjunction with the real-time intervention of the safety interlock unit, it can quickly restrict the movement of the robotic arm when the scan starts or the bed is abnormal, thus balancing positioning accuracy and operational safety, and meeting the needs of high-reliability assisted positioning in the CT environment.

[0088] Example 2

[0089] See Figure 2 The present invention also provides a robotic arm-assisted positioning method based on the linkage control of a CT bed 2, applicable to the system described in Embodiment 1. This method is implemented according to the following steps:

[0090] S1. Acquire the initial position information of CT table 2 and establish the coordinate system of CT table 2:

[0091] During system initialization, the bed monitoring unit collects the initial translational displacement of CT bed 2 in the X, Y, and Z axes, as well as the initial angular parameters around a specified axis, and establishes the CT bed 2 coordinate system accordingly. This coordinate system serves as the reference for subsequent spatial registration and pose compensation, ensuring the traceability of positional relationships between different devices. By establishing a clear initial reference, a reliable reference can be provided for subsequent dynamic compensation, reducing accumulated errors.

[0092] S2. Spatial registration of the CT image coordinate system and the robotic arm base coordinate system:

[0093] Using known calibration tools or feature markers, the CT image coordinate system and the robotic arm base coordinate system are spatially registered to determine the rigid transformation relationship between them. The registration process can employ marker-based rigid body transformation calculations or multimodal image matching methods to obtain a unified three-dimensional spatial reference frame. Through this registration, the target position in the image can be accurately mapped to the physical space where the robotic arm can perform operations, thereby ensuring the correspondence between path planning and actual operation and avoiding positioning deviations caused by coordinate system inconsistencies.

[0094] S3. Real-time acquisition of motion parameters of CT bed 2:

[0095] During the positioning process, the bed monitoring unit continuously collects real-time displacement parameters of the CT bed 2 in three orthogonal directions and angle parameters of at least one axis, and updates the bed motion parameter matrix according to the sampling period. The real-time acquired parameters can fully reflect the dynamic pose changes of the CT bed 2, providing a basis for subsequent dynamic compensation and ensuring that changes are captured in a timely manner during bed movement.

[0096] S4. Using the motion parameters of CT bed 2 as the active source of change, the reference coordinates of the robotic arm are updated in real time to dynamically compensate for the pose of the robotic arm:

[0097] The coordinate mapping unit uses the real-time acquired motion parameters of the CT bed 2 as the active source of change. Combined with the established registration relationship between the CT bed 2 coordinate system and the robotic arm base coordinate system, it performs equivalent inverse compensation calculations on the pose of the robotic arm's end effector, updates the robotic arm's reference coordinates in real time, and generates compensated pose commands. Therefore, the position of the robotic arm's end effector relative to the patient's target area remains constant during bed movement, avoiding puncture path deviation or positioning inaccuracy caused by bed displacement or rotation, thereby improving positioning accuracy and operational stability.

[0098] The dynamic compensation calculation is based on the following mathematical model: Let the motion transformation matrix of the CT bed be T. bed The target pose at the end effector of the robotic arm is T. target Then the new pose T after compensation new = T bed ×T targetBy real-time calculation of the bed motion parameters and the corresponding transformation matrix, the coordinate mapping unit performs inverse kinematics calculations on the joint angles of the robotic arm, achieving real-time pose compensation. The compensation algorithm is optimized using the recursive least squares method to ensure computational stability even in the presence of sensor noise.

[0099] In a preferred embodiment, the specific formula for dynamic compensation calculation is as follows:

[0100] Assume the bed displacement change ΔX= [Δx,Δy,Δz,Δα,Δβ,Δγ] T The joint angle compensation amount of the robotic arm is Δθ = J + (θ)×ΔX, where J + (θ) is the pseudo-inverse of the Jacobian matrix of the robotic arm, and θ is the current joint angle. This calculation method can effectively counteract the influence of bed motion on the pose of the robotic arm's end effector.

[0101] S5. Based on CT image data, plan the motion path and combine it with dynamic compensation to control the robotic arm's positioning operation:

[0102] The path planning unit reads CT image data, identifies the target area, and generates a motion path for the robotic arm to perform puncture positioning or patient immobilization procedures based on the identification results. The execution control unit, combined with the real-time compensation data from step S4, drives the robotic arm to move along the planned path, maintaining a constant position of the end effector relative to the target patient area throughout the movement. This method ensures that positioning accuracy does not decrease due to bed or patient movement while completing the predetermined operation, meeting the requirements for high-precision assisted positioning in a CT environment.

[0103] This method achieves stable maintenance of the robotic arm's end effector relative to the patient's target area during CT bed 2 movement and scanning by organically combining initial benchmark establishment, spatial registration, real-time parameter acquisition, dynamic pose compensation, and path planning execution. It effectively solves the problems of easy position drift and lack of scanning linkage control in existing technologies, and also has both positioning accuracy and operational safety.

[0104] In a preferred embodiment, the spatial registration employs the following optimization steps:

[0105] S21. High-visibility markers, such as titanium alloy positioning balls, are placed in the effective scanning area of ​​the CT bed. The three-dimensional coordinates of these markers in the image coordinate system are obtained through CT scanning. The markers are arranged in a specific geometric pattern to ensure non-collinear distribution and improve registration accuracy.

[0106] S22. Measure the physical coordinates of the corresponding marker points in the coordinate system of the robot arm base by using a contact probe or vision sensor at the end of the robot arm, and establish the coordinate correspondence.

[0107] S23. The iterative nearest-point algorithm is used to calculate the rigid body transformation matrix between the two coordinate systems. The ICP algorithm finds the optimal transformation through iterative optimization, minimizing the distance between corresponding points, achieving sub-millimeter level registration accuracy. This registration method improves the accuracy of coordinate mapping through algorithm optimization, providing a reliable transformation basis for subsequent dynamic compensation.

[0108] As a preferred embodiment, to further improve control accuracy, the dynamic compensation adopts closed-loop control, and the specific method is as follows:

[0109] S51. Real-time acquisition of position feedback signals from encoders at each joint of the robotic arm to obtain actual pose data of the robotic arm end effector;

[0110] S52. Compare the actual position with the calculated target position to calculate the pose deviation. The deviation monitoring frequency is synchronized with the bed parameter sampling to ensure real-time control.

[0111] S53. The robot arm's motion is corrected in real time using a PID control algorithm. The correction amount is calculated based on the magnitude of the deviation, the integral and derivative terms, and the joint drive output is adjusted accordingly.

[0112] In situations where the CT bed 2 moves or the patient's position changes slightly, this closed-loop control can promptly suppress end-effector position drift caused by external disturbances, ensuring the robotic arm's end-effector remains stable relative to the target area of ​​the patient. Simultaneously, when the robotic arm approaches the target point or experiences significant changes in path curvature, the closed-loop control reduces overshoot and oscillations, resulting in smoother movement and minimizing patient discomfort or equipment impact risks. By introducing position feedback and real-time correction during execution, the positioning accuracy and motion consistency of the robotic arm can be effectively improved, compensating for deviations caused by model errors or external interference in open-loop control. This enables more reliable and accurate assisted positioning in the CT bed 2 linkage environment, further enhancing the system's safety and stability.

[0113] As a preferred embodiment, the movement of the robotic arm is paused during the CT scan signal activation period, and image registration is re-performed and automatic control of the robotic arm is resumed after the scan is completed.

[0114] Specifically, the safety interlock unit communicates with the CT scanner host 1 to monitor the status of the scan control signals in real time. When it receives a scan start signal (i.e., scan signal activation) from the CT scanner, the safety interlock unit immediately sends a pause command to the execution control unit, causing the robotic arm assembly to stop its current movement and maintain a safe posture. This measure can prevent mechanical vibration or structural displacement caused by the robotic arm movement during the scan from affecting the CT imaging quality, while also preventing interference between the radiation environment during the scan and the robotic arm's movements, thus improving the safety of the system and personnel.

[0115] After the CT scan is completed, the safety interlock unit detects the scan end signal,解除暂停状态,并触发路径规划单元与坐标映射单元进行一次新的影像配准流程。该配准可利用扫描获得的更新后CT影像数据,重新计算CT影像坐标系与机械臂基座坐标系之间的空间对应关系,以修正因患者在扫描过程中体位微调或床位微小位移所引起的坐标偏差。完成配准后,执行控制单元恢复对机械臂的自动控制,使其按照更新后的参考坐标与路径继续执行定位或固定操作。

[0116] By pausing the robotic arm movement during scan activation, it can ensure that the imaging process is not mechanically interfered,保障图像清晰度与诊断有效性;扫描结束后重新进行影像配准,能够及时消除因扫描期间发生的位姿变化带来的误差,使机械臂末端在恢复控制后仍能够相对于患者目标区域保持恒定位置,从而维持定位精度与操作连续性。该改进在不增加额外硬件的前提下,实现了扫描状态与机械臂运动的可靠联动控制,兼顾了成像质量、定位准确性及系统运行安全性。

[0117] The above are only the preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural transformation made by using the content of the specification and drawings of the present invention under the inventive concept of the present invention, or direct / indirect application in other related technical fields is included in the patent protection scope of the present invention. It should be noted that there are some inaccuracies in the original Chinese text that may affect the understanding of the content. For example, in the translation of the first paragraph, "解除暂停状态" should be "解除暂停状态" which seems to be a misspelling, and it should be something like "解除暂停状态". Also, in the second paragraph, "保障图像清晰度与诊断有效性" should be "保障图像清晰度与诊断有效性". And in the third paragraph, "保障图像清晰度与诊断有效性" should be "保障图像清晰度与诊断有效性". These parts are translated as they are in the original text for the purpose of following the instructions.

Claims

1. A robotic arm-assisted positioning system based on CT bed linkage control, characterized in that, include: The CT scanner main unit is used to acquire the patient's CT image data and output scan status signals; The CT bed is equipped with a bed position detection sensor to detect the movement of the CT bed in at least the translation, lifting and tilting directions in real time. The telescopic support is installed on the outer shell of the CT machine main unit. The telescopic support is arranged in a direction parallel to the long axis of the CT bed, and its telescopic stroke covers the effective operating area of ​​the CT bed. At least one robotic arm assembly is disposed at the movable end of a telescopic support; The linkage control module is communicatively connected to the bed position detection sensor, the CT scanner main unit, and the robotic arm assembly; the linkage control module is configured as follows: Establish a spatial mapping relationship between the CT image coordinate system, the CT bed coordinate system, and the robotic arm base coordinate system; use the real-time motion parameters of the CT bed as input, and calculate the pose compensation amount of the robotic arm end effector through coordinate transformation; dynamically control the robotic arm according to the pose compensation amount, so that the robotic arm end effector maintains a constant position relative to the patient target area.

2. The robotic arm-assisted positioning system based on CT bed linkage control according to claim 1, characterized in that, The robotic arm assembly has at least six degrees of freedom, and its end is detachably fitted with a puncture guide, needle holder, or patient fixation device.

3. A robotic arm-assisted positioning system based on CT bed linkage control according to claim 1 or 2, characterized in that, The linkage control module includes: The bed monitoring unit is used to collect the displacement and angle parameters of the CT bed and form a motion parameter matrix; The coordinate mapping unit calculates the equivalent inverse compensation amount of the robot arm pose based on the motion parameter matrix; The path planning unit generates the robotic arm's motion path based on CT image data; The safety interlock unit controls the state of the robotic arm when it is in scanning mode or when parameters exceed limits.

4. The robotic arm-assisted positioning system based on CT bed linkage control according to claim 3, characterized in that, The bed monitoring unit is used to collect the displacement parameters of the CT bed in three orthogonal directions and the angle parameters around at least one axis in real time, and form a bed motion parameter matrix.

5. The robotic arm-assisted positioning system based on CT bed linkage control according to claim 3, characterized in that, The coordinate mapping unit calculates the compensation amount using the following formula: Δθ = J + (θ) × ΔX; Where Δθ is the joint angle compensation amount, J + (θ) is the pseudo-inverse of the Jacobian matrix of the robotic arm, and ΔX is the change in bed motion.

6. The robotic arm-assisted positioning system based on CT bed linkage control according to claim 3, characterized in that, The path planning unit identifies the target area based on CT image data and generates a motion path for the robotic arm to perform puncture positioning or patient fixation operations.

7. The robotic arm-assisted positioning system based on CT bed linkage control according to claim 3, characterized in that, The safety interlock unit is configured to: control the robotic arm assembly to pause movement when the CT scanner host is detected to be in scanning mode; or control the robotic arm assembly to enter a locked state when the motion parameters of the CT bed are detected to exceed a preset safety threshold.

8. A robotic arm-assisted positioning method based on CT bed linkage control, applied to the system described in any one of claims 1-7, characterized in that, The steps include: S1. Acquire the initial position information of the CT bed and establish the CT bed coordinate system; S2. Spatial registration is performed between the CT image coordinate system and the robotic arm base coordinate system to obtain the coordinate transformation relationship; S3. Real-time acquisition of CT bed motion parameters; S4. Using the motion parameters of the CT bed as the active source of change, the reference coordinates of the robotic arm are updated in real time through rigid body transformation calculation. S5. Based on CT image data, plan the motion path and combine dynamic compensation to control the positioning operation of the robotic arm.

9. The positioning method according to claim 8, characterized in that, The spatial registration adopts the following steps: S21. Place imaging markers on the CT bed and obtain image coordinates through CT scanning; S22. Obtain the corresponding coordinates in the robotic arm coordinate system through robotic arm contact measurement; S23. Use the ICP algorithm to calculate the rigid body transformation matrix between coordinate systems.

10. The positioning method according to claim 8, characterized in that, The dynamic compensation employs closed-loop control, and the specific method is as follows: S51. Real-time acquisition of robotic arm position feedback signals; S52. Compare the deviation between the actual position and the target position; S53. The robot arm motion is corrected in real time using a PID algorithm.

Images