A robot radiotherapy bed absolute positioning accuracy guarantee system and an accuracy guarantee method thereof

Abstract

The application relates to a robot radiotherapy bed absolute positioning precision guarantee system and a precision guarantee method thereof, and the application comprises a debugging stage calibration module and a treatment stage calibration module; the debugging stage calibration module comprises a joint arm measuring device, a calibration tool and a robot radiotherapy bed; the calibration tool is arranged at the front end of a sliding table base of the robot radiotherapy bed, and the joint arm measuring device is arranged on the base of the robot radiotherapy bed; the treatment stage calibration module comprises a camera, a marking tool and a radiotherapy equipment host; the camera is arranged at the rear side of the top of the radiotherapy equipment host; and the marking tool is arranged at the front end of a positioning bed of the robot radiotherapy bed. The application calculates the error between the position of the treatment bed in a treatment state and the same position in a zero load state in real time, and compensates in real time according to the error, so that the absolute positioning precision of the robot radiotherapy bed is improved, and the accuracy of radiotherapy is ensured.

Description

Technical Field

[0001] This invention relates to the field of radiotherapy, and more particularly to a method for ensuring the absolute positioning accuracy of a robotic radiotherapy bed. Background Technology

[0002] The treatment bed in radiotherapy equipment is a multi-axis motion platform whose core function is to precisely position the patient to the treatment location according to the treatment plan. To adapt to diverse treatment needs, five-dimensional and even six-dimensional treatment beds are gradually being applied to radiotherapy systems. Traditional radiotherapy treatment beds mostly adopt a parallel structure; however, this structure has problems such as complex design, large size, and high minimum height, which not only increases the difficulty of hospital room renovation but also makes it inconvenient for patients to get in and out of the bed.

[0003] In recent years, with the rapid development of industrial robot technology, its application in the medical field has become increasingly widespread. Treatment beds designed based on industrial robot principles, due to their simple structure and low minimum height, are expected to effectively overcome many drawbacks of traditional treatment beds and are gradually becoming an important direction for the development of radiotherapy equipment treatment beds. However, the inherent problem of low absolute positioning accuracy in industrial robots severely restricts the widespread application of this type of treatment bed in radiotherapy.

[0004] Therefore, it is urgent to research and propose a method to ensure the absolute positioning accuracy of robotic radiotherapy beds, so as to ensure that radiotherapy beds based on industrial robot technology can meet the requirements of absolute positioning accuracy for radiotherapy while inheriting the advantages of industrial robots such as simplified structure and low bed height, thereby ensuring the treatment effect. Summary of the Invention

[0005] To address the aforementioned technical problems in the background art, this invention provides an absolute positioning accuracy system for a robotic radiotherapy bed and a method for ensuring its accuracy. The system calculates in real time the error between the position of the treatment bed under treatment and the same position under zero load, and compensates for this error in real time, thereby improving the absolute positioning accuracy of the robotic radiotherapy bed and ensuring the precision of radiotherapy.

[0006] The technical solution of this invention is as follows: This invention is a system for ensuring the absolute positioning accuracy of a robotic radiotherapy bed. Its unique feature is that the system includes a calibration module for the debugging stage and a calibration module for the treatment stage. The calibration module for the debugging stage includes an articulated arm measuring device, a calibration fixture, and the robotic radiotherapy bed. The calibration fixture is located at the front end of the slide base of the robotic radiotherapy bed, and the articulated arm measuring device is located on the base of the robotic radiotherapy bed. The calibration module for the treatment stage includes a camera, a marking fixture, and the main unit of the radiotherapy equipment. The camera is located on the top rear side inside the main unit of the radiotherapy equipment; the marking fixture is located at the front end of the positioning bed of the robotic radiotherapy bed.

[0007] The aforementioned calibration fixture includes a spherical calibration fixture and a cubic calibration block; the spherical calibration fixture is mounted on the cubic calibration block, and the cubic calibration block is mounted on the front end of the slide base of the robotic radiotherapy bed.

[0008] Furthermore, the marking fixture includes a support and multiple marking balls. The marking balls are distributed on the support in such a way that the centers of all the marking balls are not coplanar. The support is set at the front end of the positioning bed of the robotic radiotherapy bed.

[0009] Furthermore, three or more balls are marked.

[0010] This invention also provides a method for ensuring the accuracy of the above-mentioned robotic radiotherapy bed absolute positioning accuracy assurance system, characterized in that the method includes the following steps:

[0011] 1) During the debugging phase, the calibration steps are as follows:

[0012] 1.1) Using articulated arm measuring equipment, an initial coordinate system is obtained based on the base of the robotic radiotherapy bed. Starting from the bottom layer of the robotic radiotherapy bed, the zero position of each joint axis is calibrated one by one to obtain the posture deviation of each joint axis based on the initial coordinate system after zero calibration.

[0013] 1.2) Based on the theoretical motion model of the robotic radiotherapy bed, the actual values ​​of each parameter in the motion model of the robotic radiotherapy bed are obtained using articulated arm measuring equipment;

[0014] 1.3) Based on the actual kinematic parameters obtained in step 1.2), the motion model of the robot radiotherapy bed is corrected;

[0015] 1.4) Install the calibration fixture at the front end of the slide base of the robotic radiotherapy bed, with each motion axis at zero position. Use an articulated arm measuring device to establish a reference coordinate system based on the calibration fixture, and define the center of the spherical calibration fixture in this state as (0, 0, 0). Take M calibration points sequentially along a certain direction at equal intervals within the travel range. Obtain the theoretical coordinates of the center of the spherical calibration fixture at the M calibration positions in the motion model. Control the robotic radiotherapy bed to move sequentially to the M calibration points. At each calibration point, use the articulated arm measuring device to calibrate the coordinates of the center of the spherical calibration fixture at that position, and compare them with the theoretical coordinates to obtain the actual motion error. Based on the attitude deviation of each joint axis obtained in step 1.1) based on the initial coordinate system, process the motion error value to eliminate the influence of the initial attitude of the robotic radiotherapy bed on the calibration. After processing, analyze the motion error using mathematical methods such as variance, covariance, standard deviation, and root mean square value to compensate the control model, thereby improving the positioning accuracy of the robotic radiotherapy bed.

[0016] 2) The real-time calibration steps in the pre-treatment stage are described below:

[0017] 2.1) The camera tracks the marker ball at the front end of the robotic radiotherapy bed to obtain the position of the robotic radiotherapy bed 13 in real time during the treatment state; the real-time position of the robotic radiotherapy bed under variable load is compared with the position data calibrated in the zero load state in step 1.4) to obtain the motion error;

[0018] 2.2) Determine if the error meets the threshold; if the error exceeds the threshold, proceed to step 2.3); if the error does not exceed the threshold, begin treatment.

[0019] 2.3) The robot radiotherapy bed is controlled to compensate for motion errors in order to improve positioning accuracy and ensure treatment effectiveness;

[0020] 2.4) The camera calibrates the marker ball on the robot radiotherapy bed and obtains the corrected position data; compares it with the position data calibrated in the zero-load state in step 1.4) to obtain the error value; determines whether the error value meets the threshold requirement. If it does, treatment begins; if not, correction continues to ensure that the final applied position meets the expected requirements to guarantee the treatment effect.

[0021] This invention provides a system and method for ensuring the absolute positioning accuracy of a robotic radiotherapy bed, comprising a debugging phase and a treatment phase. In the debugging phase, the kinematic parameters of the robotic radiotherapy bed are first calibrated using an articulated arm measuring device, and its kinematic model is corrected based on the actual parameters obtained from the calibration. Subsequently, the absolute positioning accuracy of the robotic radiotherapy bed is calibrated again using the articulated arm measuring device to correct the operating parameters of the treatment bed under zero-load conditions. In the treatment phase, a marker ball is placed at the front end of the robotic radiotherapy bed, and a camera tracks the marker ball in real time to determine the actual position and orientation of the treatment bed during treatment. The error between the position of the treatment bed under treatment and the same position under zero-load conditions is calculated in real time, and compensation is performed in real time based on this error, thereby improving the absolute positioning accuracy of the robotic radiotherapy bed and ensuring the precision of radiotherapy. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural schematic diagram of the present invention;

[0023] Figure 2 This is a schematic diagram of the calibration module structure during the debugging phase of the present invention;

[0024] Figure 3 This is a three-dimensional structural schematic diagram of the calibration tooling of the present invention;

[0025] Figure 4 This is a three-dimensional structural schematic diagram of the marking fixture of the present invention;

[0026] Figure 5This is a schematic diagram of the calibration position in an application embodiment of the present invention;

[0027] Figure 6 This is a flowchart of the method of the present invention.

[0028] The annotations in the attached figures are explained as follows:

[0029] 1. Calibration module for the debugging phase; 2. Calibration module for the treatment phase;

[0030] 11. Articulated arm measuring equipment; 12. Calibration fixture; 13. Robotic radiotherapy bed;

[0031] 121; Spherical calibration fixture; 122; Cube calibration block;

[0032] 21. Camera; 22. Marking fixture; 23. Radiotherapy equipment main unit;

[0033] 221. Support; 222. Marker ball. Detailed Implementation

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

[0035] See Figure 1 , 2 The structure of the absolute positioning accuracy guarantee system for the robotic radiotherapy bed of the present invention includes a calibration module 1 for the debugging stage and a calibration module 2 for the treatment stage. The calibration module 1 for the debugging stage includes an articulated arm measuring device 11, a calibration fixture 12, and a robotic radiotherapy bed 13. The calibration fixture 12 is disposed at the front end of the slide base of the robotic radiotherapy bed 13, and the articulated arm measuring device 11 is disposed on the base of the robotic radiotherapy bed 13. The calibration module 2 for the treatment stage includes a camera 21, a marking fixture 22, and a radiotherapy equipment host 23. The camera 21 is disposed on the rear side of the top inside the radiotherapy equipment host 23. The marking fixture 22 is disposed at the front end of the positioning bed of the robotic radiotherapy bed 13.

[0036] Among them, the articulated arm measuring device 11, the robotic radiotherapy bed 13, the camera 21, and the radiotherapy equipment host 23 are all existing structures.

[0037] See Figure 3 The calibration fixture 12 of the present invention has a structure including a spherical calibration fixture 121 and a cube calibration block 122; the spherical calibration fixture 121 is disposed on the cube calibration block 122, and the cube calibration block 122 is disposed at the front end of the slide base of the robotic radiotherapy bed 13.

[0038] See Figure 4The marking fixture 22 of the present invention includes a support 221 and multiple marking balls 222 in a specific embodiment. The marking balls 222 are distributed on the support 222 such that the centers of all the marking balls 222 are not coplanar. The support 222 is located at the front end of the positioning bed of the robotic radiotherapy bed 222. There are three or more marking balls 222. In this embodiment, there are three marking balls 222.

[0039] See Figure 5 , 6 The present invention also provides a method for ensuring the accuracy of the above-mentioned robotic radiotherapy bed absolute positioning accuracy assurance system, the method comprising the following steps:

[0040] 1) During the debugging phase, the calibration steps are as follows:

[0041] 1.1) Using the articulated arm measuring device 11, an initial coordinate system is obtained based on the base of the robot radiotherapy bed 13. Starting from the bottom layer of the robot radiotherapy bed 13, the zero position of each joint axis is calibrated one by one to obtain the posture deviation of each joint axis based on the initial coordinate system after zero calibration.

[0042] 1.2) Based on the theoretical motion model of the robotic radiotherapy bed 13, the actual values ​​of each parameter in the motion model of the robotic radiotherapy bed 13 are obtained using the articulated arm measuring device 11;

[0043] 1.3) Based on the actual kinematic parameters obtained in step 1.2), the motion model of the robot radiotherapy bed 13 is corrected;

[0044] 1.4) Install the calibration fixture 12 on the front end of the slide base of the robotic radiotherapy bed 13, with each motion axis at zero position. Using the articulated arm measuring device 11, establish a reference coordinate system based on the calibration fixture 12, and define the center of the spherical calibration fixture 121 in this state as (0, 0, 0). Take M calibration points sequentially along a certain direction at equal intervals within the stroke range, obtain the theoretical coordinates of the center of the spherical calibration fixture 121 at the M calibration positions in the motion model, and control the robotic radiotherapy bed 13 to move sequentially to the M calibration points. The calibration point is determined by using the articulated arm measuring device 11 to calibrate the coordinates of the center of the sphere at that location using the spherical calibration fixture 121. The actual motion error is then compared with the theoretical coordinates. Based on the posture deviation of each joint axis obtained in step 1.1) according to the initial coordinate system, the motion error value is processed to eliminate the influence of the initial posture of the robot radiotherapy bed 13 on the calibration. The processed motion error is then analyzed using mathematical methods such as variance, covariance, standard deviation, and root mean square value to compensate the control model, thereby improving the positioning accuracy of the robot radiotherapy bed 13.

[0045] 2) The real-time calibration steps in the pre-treatment stage are described below:

[0046] 2.1) Camera 21 tracks the marker ball 222 at the front end of the robotic radiotherapy bed 13 to obtain the position of the robotic radiotherapy bed 13 in real time during the treatment state; the real-time position of the robotic radiotherapy bed 13 under variable load is compared with the position data calibrated in the zero load state in step 1.4) to obtain the motion error;

[0047] 2.2) Determine if the error meets the threshold; if the error exceeds the threshold, proceed to step 2.3); if the error does not exceed the threshold, begin treatment.

[0048] 2.3) The robot radiotherapy bed 13 is controlled to compensate for motion errors in order to improve positioning accuracy and ensure treatment effect;

[0049] 2.4) Camera 21 calibrates the marker ball 222 on the robot radiotherapy bed 13 and obtains the corrected position data; compares it with the position data calibrated in the zero-load state in step 1.4) to obtain the error value; determines whether the error value meets the threshold requirement. If it does, treatment begins; if not, correction continues to ensure that the final application position meets the expected requirements to guarantee the treatment effect.

[0050] The technical contents of this invention and those not specifically described in the above embodiments are the same as those in the prior art.

[0051] The above are merely specific embodiments disclosed in this invention, but the scope of protection disclosed in this invention is not limited thereto. The scope of protection disclosed in this invention should be determined by the scope of the claims.

Claims

1. A method for ensuring the accuracy of an absolute positioning accuracy assurance system for a robotic radiotherapy bed, characterized in that: The absolute positioning accuracy assurance system for the robotic radiotherapy bed includes a calibration module for the debugging stage and a calibration module for the treatment stage. The calibration module for the debugging stage includes an articulated arm measuring device, a calibration fixture, and the robotic radiotherapy bed. The calibration fixture is located at the front end of the slide base of the robotic radiotherapy bed, and the articulated arm measuring device is located on the base of the robotic radiotherapy bed. The calibration module for the treatment stage includes a camera, a marking fixture, and the radiotherapy equipment host. The camera is located on the top rear side inside the radiotherapy equipment host. The marking fixture is located at the front end of the positioning bed of the robotic radiotherapy bed, and the calibration fixture includes a spherical calibration fixture and a cubic calibration block. The spherical calibration fixture is mounted on a cube calibration block, which is positioned at the front end of the slide base of the robotic radiotherapy bed. The marking fixture includes a support and multiple marking balls, which are distributed on the support such that the centers of all the marking balls are not coplanar. The support is positioned at the front end of the positioning bed of the robotic radiotherapy bed, and there are three or more marking balls. This accuracy assurance method includes the following steps: 1) During the debugging phase, the calibration steps are as follows: 1.1) Using articulated arm measuring equipment, an initial coordinate system is obtained based on the base of the robotic radiotherapy bed. Starting from the bottom layer of the robotic radiotherapy bed, the zero position of each joint axis is calibrated one by one to obtain the posture deviation of each joint axis based on the initial coordinate system after zero calibration. 1.2) Based on the theoretical motion model of the robotic radiotherapy bed, the actual values ​​of each parameter in the motion model of the robotic radiotherapy bed are obtained using articulated arm measuring equipment; 1.3) Based on the actual kinematic parameters obtained in step 1.2), the motion model of the robot radiotherapy bed is corrected; 1.4) Install the calibration fixture at the front end of the slide base of the robotic radiotherapy bed, with each motion axis at zero position. Use an articulated arm measuring device to establish a reference coordinate system based on the calibration fixture, and define the center of the spherical calibration fixture in this state as (0, 0, 0). Take M calibration points sequentially along a certain direction at equal intervals within the travel range. Obtain the theoretical coordinates of the center of the spherical calibration fixture at the M calibration positions in the motion model. Control the robotic radiotherapy bed to move sequentially to the M calibration points. At each calibration point, use the articulated arm measuring device to calibrate the coordinates of the center of the spherical calibration fixture at that position, and compare them with the theoretical coordinates to obtain the actual motion error. Based on the attitude deviation of each joint axis obtained in step 1.1) based on the initial coordinate system, process the motion error value to eliminate the influence of the initial attitude of the robotic radiotherapy bed on the calibration. After processing, analyze the motion error using mathematical methods such as variance, covariance, standard deviation, and root mean square value to compensate the control model and improve the positioning accuracy of the robotic radiotherapy bed. 2) The real-time calibration steps in the pre-treatment stage are described below: 2.1) The camera tracks the marker ball at the front end of the robotic radiotherapy bed to obtain the position of the robotic radiotherapy bed in real time during the treatment state; the real-time position of the robotic radiotherapy bed under variable load is compared with the position data calibrated in the zero-load state in step 1.4) to obtain the motion error; 2.2) Determine if the error meets the threshold; if the error exceeds the threshold, proceed to step 2.3); if the error does not exceed the threshold, begin treatment. 2.3) The control robot radiotherapy bed is compensated and corrected according to motion errors; 2.4) The camera calibrates the marker ball on the radiotherapy bed of the robot and obtains the corrected position data; compares it with the position data calibrated in the zero-load state in step 1.4) to obtain the error value; determines whether the error value meets the threshold requirement. If it does, treatment begins; otherwise, correction continues.

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