A multi-axis medical imaging device automatic change finding method and system

Abstract

The application relates to a multi-axis medical imaging device automatic zero-finding method and system, which comprises the following steps: starting a target motion axis automatic zero-finding process; acquiring a real-time working state of a zero-position sensor corresponding to a current motion axis; judging whether the zero-position sensor is currently in a triggered state; if yes, controlling the motion axis to exit a sensor effective area; if not, controlling the motion axis to perform a limited distance reverse trial and carry out coarse search positioning; controlling the motion axis to carry out fine search positioning and acquire a reference edge position of sensor level switching; performing compensation calculation on the reference edge position to obtain a theoretical zero point coordinate; zero point locking and verification, and if the verification is passed, the current motion axis zero-finding is completed; all motion axis zero-findings are sequentially completed according to a preset zero-finding execution sequence, a unified mechanical coordinate system of the whole machine is constructed, and the whole machine automatic zero-finding process is ended. The application can realize safe, reliable and high-repetitive mechanical coordinate establishment under the condition of unknown initial mechanical coordinates.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical imaging equipment mechanical motion control, and in particular to a multi-axis medical imaging equipment automatic zero finding method and system. BACKGROUND

[0002] In a multi-axis motion device (such as a medical imaging equipment such as a cone beam CT), after the device is powered off, initialization is completed, or maintenance is completed, the mechanical zero point usually needs to be re-established to normally carry out work.

[0003] Currently, the main implementation ways of establishing the mechanical zero point in the industry are divided into two kinds: the first kind is manual zero finding, which needs an operator to control the low-speed movement of each motion axis, to determine the zero point position by observing the trigger state of the photoelectric sensor, and then to manually execute the encoder coordinate zero clearing. This way is time-consuming in operation, the zero point repeatability depends on the experience of the operator, and the consistency of batch devices is poor. The second kind is controller fixed zero, that is, some motion controllers provide a home function, which detects the original point signal through fixed direction movement and stops after triggering. This way cannot effectively handle abnormal states such as the initial position of the motion axis staying in the sensor trigger area or slightly overrunning the sensor area.

[0004] In summary, for multi-axis medical imaging equipment, such as a multi-axis system with a bed body and a U-shaped arm, the existing zero finding schemes all have various defects:

[0005] 1. The initial position adaptation capability is insufficient, and it cannot adapt to abnormal initial parking conditions such as the motion axis staying in the sensor trigger area or slightly overrunning;

[0006] 2. The first trigger position of the sensor is directly taken as the zero point, which is affected by the sensor installation error, mechanical error and stopping error;

[0007] 3. The absolute coordinates of each axis may be unknown when the device starts, and the safety judgment cannot be directly made by using the anti-collision model based on forward kinematics and absolute coordinates, and mechanical interference is likely to occur during the movement of the gantry;

[0008] 4. The multi-axis device usually cannot automatically plan the zero finding sequence according to the mechanical dependence relationship of each axis, and still needs manual sorting operation. SUMMARY

[0009] The present application provides a multi-axis medical imaging equipment automatic zero finding method and system to solve the above technical problems.

[0010] To solve the above technical problems, the present application provides a multi-axis medical imaging equipment automatic zero finding method, which includes a plurality of bed body motion axes and a plurality of U-shaped arm motion axes, each motion axis is respectively configured with an independent drive and an independent zero position sensor, and the automatic zero finding method includes the following steps:

[0011] Step 1: Start the automatic zeroing process of the target motion axis and perform system initialization checks;

[0012] Step 2: Obtain the real-time working status of the zero-position sensor corresponding to the motion axis to be calibrated;

[0013] Step 3: Determine if the zero-position sensor is currently in a triggered state:

[0014] If it is determined that the zero-position sensor has been triggered, the motion axis is controlled to exit the effective area of ​​the sensor, and the sensor release process is executed to restore the zero-position sensor to a stable, untriggered state.

[0015] If it is determined that the zero-position sensor has not been triggered, the motion axis is controlled to perform a limited-distance reverse probe to determine whether the motion axis has crossed the sensor area.

[0016] If the sensor area is not crossed, the sensor area is searched along the preset direction at the first speed to perform coarse search and positioning.

[0017] If the motion axis has already crossed the sensor area, adjust the direction of motion of the motion axis and then perform coarse search and positioning.

[0018] Step 4: Control the motion axis to approach the sensor signal transition edge along a fixed direction at a second speed, perform fine search and positioning, and obtain the reference edge position of the sensor level switching. The first speed is greater than the second speed. If an abnormal situation occurs during operation, trigger the error reporting program and terminate the current motion axis zeroing.

[0019] Step 5: Based on mechanical design offset, assembly error, and calibration results, perform compensation calculations on the reference edge position to obtain the theoretical zero-point coordinates;

[0020] Step 6: The theoretical zero-point coordinates are written into the controller to complete the zero-point locking. Then, the zero-point coordinates are verified. If the verification is successful, the current motion axis has completed zero finding.

[0021] Step 7: Perform steps 1 to 6 above on all motion axes in sequence according to the preset zeroing execution sequence. After all motion axes have been zeroed and verified, a unified mechanical coordinate system for the whole machine is established, and the automatic zeroing process of the whole machine ends.

[0022] Preferably, in step 1, the items checked during system initialization include at least the controller status, motion axis status, driver status, emergency stop status, I / O signals, and safety conditions.

[0023] Preferably, in step 1, if the initialization check fails, an error reporting procedure is triggered and the current automatic change-making process is terminated.

[0024] Preferably, in step 4, the abnormal conditions include at least running timeout, sensor failure, and excessive motion range.

[0025] Preferably, when the machine first starts the automatic zeroing process, the machine switches to a non-zeroing safety mode. After completing the establishment of the unified mechanical coordinate system for the entire machine, it exits the non-zeroing safety mode. During the operation of the non-zeroing safety mode, the following control strategies are implemented:

[0026] Disable the standard collision avoidance algorithm based on positive kinematics and absolute coordinates;

[0027] Each motion axis satisfies the triple motion limits of maximum speed, maximum distance, and maximum time.

[0028] Based on the mechanical dependencies of each motion axis pre-stored in the system, the zero-finding execution sequence is automatically generated.

[0029] Preferably, the motion of each motion axis in steps 1 to 6 satisfies the triple motion constraint.

[0030] Preferably, after exiting the non-zeroing safety mode, the standard collision avoidance algorithm is enabled.

[0031] This invention also provides an automatic zeroing control system for multi-axis medical imaging equipment, used to execute the above-mentioned automatic zeroing method for multi-axis medical imaging equipment, including a motion controller and a host computer control module.

[0032] The motion controller is used to control the driver to control the movement of each motion axis and to read the status of the zero-position sensor;

[0033] The host computer control module is used to execute the automatic change-finding process, task management, and status feedback of steps 1 to 7.

[0034] Preferably, the host computer control module has a built-in safety management unit, which is used to switch to the non-zeroing safety mode when the whole machine starts the zeroing task, disable the standard anti-collision algorithm, load the triple motion restrictions of each motion axis, and generate an interference-free zeroing sequence according to the mechanical dependency relationship between each motion axis.

[0035] Compared with the prior art, the automatic zeroing method and system for multi-axis medical imaging equipment provided by the present invention has the following advantages:

[0036] 1. This invention can automatically complete the zero-point calibration of multi-axis machinery throughout the entire process, without the need for manual adjustment of the initial position of the shaft or manual arrangement of the zero-finding sequence, which greatly reduces manual intervention, lowers the probability of human error, and improves the automation level of equipment calibration.

[0037] 2. This invention adopts a two-level positioning strategy of phased coarse search and low-speed fine search, accurately capturing the reference edge of sensor level switching as the positioning benchmark, which effectively improves the zero-point positioning repeatability accuracy compared with the single trigger point acquisition method.

[0038] 3. This invention introduces compensation calculations for sensor installation deviation, mechanical assembly offset, and stopping error, corrects the edge reference position to obtain the theoretical zero point coordinates, and significantly reduces the interference of various inherent errors on zero point accuracy;

[0039] 4. When there are no reliable absolute coordinates, the present invention enables the non-zero safety mode, temporarily disables the standard anti-collision algorithm that relies on absolute coordinates, and configures triple motion constraints of maximum speed, maximum distance and maximum time, which can effectively avoid the risk of mechanical collision interference caused by unknown coordinates and ensure the safe operation of the calibration process.

[0040] 5. The invention is equipped with a dedicated automatic zero-finding control system to realize the solution, which is compatible with multi-axis medical imaging equipment with bed axis and U-shaped arm axis combination, and can also be extended to various complex multi-axis industrial equipment, with a wide range of applications. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the hardware layout of the automatic zero-finding system for multi-axis medical imaging equipment in a specific embodiment of the present invention;

[0042] Figure 2 This is a flowchart of an automatic zeroing method for multi-axis medical imaging equipment according to a specific embodiment of the present invention;

[0043] Figure 3 This is a flowchart of the multi-axis motion constraint in the non-zero safety mode according to a specific embodiment of the present invention.

[0044] In the diagram: 100 - Bed body, 111 - Bed body forward and backward movement axis, 112 - Bed body forward and backward movement zero-position sensor, 121 - Bed body lifting and lowering axis, 122 - Bed body lifting and lowering zero-position sensor, 131 - Bed body rotation axis, 132 - Bed body rotation zero-position sensor, 200 - U-shaped arm, 211 - U-shaped arm lifting and lowering axis, 212 - U-shaped arm lifting and lowering zero-position sensor, 221 - U-shaped arm rotation axis, 222 - U-shaped arm rotation zero-position sensor. Detailed Implementation

[0045] To illustrate the technical solutions of the invention in more detail, specific embodiments are listed below to demonstrate the technical effects; it should be emphasized that these embodiments are used to illustrate the invention and not to limit the scope of the invention.

[0046] The present invention provides an automatic zeroing method for multi-axis medical imaging equipment, wherein the multi-axis medical imaging equipment is as follows: Figure 1As shown, the system includes a bed 100 and a U-shaped arm 200. The bed 100 is equipped with a bed-to-back movement axis 111, a bed-to-height movement axis 121, and a bed-to-rotation movement axis 131, each corresponding to a bed-to-back movement zero-position sensor 112, a bed-to-height movement zero-position sensor 122, and a bed-to-rotation movement zero-position sensor 132, respectively. The U-shaped arm 200 is equipped with a U-shaped arm-to-height movement axis 211 and a U-shaped arm-to-rotation movement axis 221, each corresponding to a U-shaped arm-to-height movement zero-position sensor 212 and a U-shaped arm-to-rotation movement zero-position sensor 222, respectively. Each movement axis is equipped with an independent driver and an independent zero-position sensor. In this embodiment, each zero-position sensor serves as a zero-position detection element, capable of providing real-time feedback on the position status of the axis, providing initial detection signals for subsequent coarse and fine searches, and identifying various initial working conditions such as the axis remaining in the sensor trigger area or crossing the sensor area.

[0047] Please refer to this carefully. Figure 2 The automatic change method includes the following steps:

[0048] Step 1: Start the automatic zeroing process of the target motion axis and perform system initialization checks: Before the formal zeroing action is executed, complete the basic status verification of the whole machine. The items checked include at least the controller status, motion axis status, driver status, emergency stop status, IO signals and safety conditions. The multi-dimensional initialization check covers hardware, signals and safety interlocks, which can identify hardware faults in advance and prevent zeroing actions from being carried out with faults.

[0049] Step 2: Obtain the real-time working status of the zero-position sensor corresponding to the motion axis to be calibrated. Taking the bed forward and backward movement motion axis 111 as an example, read the output signal of the bed forward and backward movement zero-position sensor 112 to determine the actual position of the axis relative to the sensor.

[0050] Step 3: Determine if the zero-position sensor is currently in a triggered state:

[0051] If it is determined that the zero-position sensor has been triggered, the motion axis is controlled to exit the effective area of ​​the sensor, and the sensor release process is executed to restore the zero-position sensor to a stable, untriggered state.

[0052] If it is determined that the zero-position sensor has not been triggered, the motion axis is controlled to perform a limited-distance reverse probe to determine whether the motion axis has slightly crossed the sensor area;

[0053] If the sensor area is not crossed, the sensor area is searched along the preset direction at the first speed to perform coarse search and positioning.

[0054] If the motion axis has already crossed the sensor area, adjust the direction of travel of the motion axis and then perform a coarse search for positioning. This branch logic is compatible with various initial parking positions of the axis, eliminating the need for manual movement of the motion axis. Calibration can be performed directly after the device is powered on, solving the problem of strict requirements on the initial position of the motion axis in traditional zeroing solutions.

[0055] Step 4: Control the motion axis to approach the sensor signal transition edge along a fixed direction at a second speed, perform fine search positioning, and obtain the reference edge position of the sensor level switching. The first speed is greater than the second speed. If an abnormality occurs during operation, an error reporting program is triggered and the current motion axis zeroing is terminated. This invention employs a combination of coarse and fine search. The coarse search uses a higher first speed to quickly approach the target range, while the fine search uses a lower second speed to acquire the level transition edge, balancing calibration efficiency and positioning accuracy. Once an abnormality is detected, single-axis zeroing is immediately terminated to prevent continued movement under fault conditions from causing equipment damage.

[0056] Step 5: Based on the mechanical design offset, assembly error and calibration results, perform compensation calculation on the reference edge position to obtain the theoretical zero point coordinates, that is: theoretical zero point coordinates = reference edge position + compensation amount. Then, the above-mentioned systematic error is eliminated by the compensation amount, and the accuracy of the zero point coordinates is further improved.

[0057] Step 6: The theoretical zero-point coordinates are written to the controller to complete zero-point locking. Then, zero-point verification is performed on the written zero-point coordinates. If the verification passes, the zeroing of the current motion axis is complete. Adding a verification step after zero-point writing prevents zero-point data errors caused by writing anomalies, ensuring the reliability and reproducibility of single-axis calibration results.

[0058] Step 7: Perform steps 1 to 6 of the above steps sequentially for all motion axes according to the preset zeroing execution sequence. After all motion axes have been zeroed and verified, establish a unified mechanical coordinate system for the entire machine, and the automatic zeroing process for the entire machine ends. After each axis has been calibrated, the coordinate system for the entire machine is established to ensure that the coordinate references of all motion axes of the bed 100 and all motion axes of the U-arm 200 are unified, providing a reliable coordinate basis for the subsequent motion control of the equipment.

[0059] In some embodiments, if the initialization check fails in step 1, an error reporting procedure is triggered and the automatic change process is terminated, thus avoiding unsafe movements from the source.

[0060] In some embodiments, in step 4, the abnormal situations include at least running timeout, sensor failure, and motion stroke exceeding limits. Multi-dimensional fallback protection means that zero finding will stop if any of the abnormalities occurs during the motion process.

[0061] In some embodiments, please refer to the following: Figure 3When the automatic zeroing process is started for the first time, the machine switches to the non-zeroing safety mode. After the unified mechanical coordinate system of the whole machine is established, it exits the non-zeroing safety mode.

[0062] The following control strategies are implemented during the operation of the non-zeroing security mode:

[0063] Disable the standard collision avoidance algorithm based on positive kinematics and absolute coordinates;

[0064] Each motion axis satisfies the triple motion limits of maximum speed, maximum distance, and maximum time.

[0065] Based on the mechanical dependencies of each motion axis pre-stored in the system, the zero-finding execution sequence is automatically generated.

[0066] When the equipment has not yet established a whole coordinate system, there is no effective absolute coordinate data, and the original standard anti-collision algorithm that relies on absolute coordinates cannot be effective. The safety mode provided by this invention temporarily disables the standard anti-collision algorithm, relies on triple hard motion constraints for motion constraints, and automatically outputs an interference-free zero-finding execution sequence. There is no need to manually arrange the calibration order of motion axes, thus avoiding the risk of mechanical collisions under unknown coordinates.

[0067] In some embodiments, the motion of each motion axis in steps 1 to 6 satisfies the triple motion constraints. The entire single-axis zero-finding process is constrained by maximum speed, maximum distance, and maximum time. Even in the single-axis motion phase, there is safety protection. Safety control covers all zero-finding actions and is not limited to the multi-axis collaborative phase.

[0068] In some embodiments, after exiting the non-zeroing safety mode, the standard anti-collision algorithm is enabled. Once the overall coordinate system is established and reliable absolute coordinates are available, the original standard anti-collision algorithm is restored, and the device returns to normal operation protection logic.

[0069] Please refer to this carefully. Figure 1 and combined Figure 2 The present invention also provides an automatic zeroing control system for multi-axis medical imaging equipment, used to execute the above-mentioned automatic zeroing method for multi-axis medical imaging equipment, including a motion controller and a host computer control module.

[0070] The motion controller is used to control the drive to control the movement of the bed forward and backward movement axis 111, the bed lifting movement axis 121, the bed rotation movement axis 131, the U-arm lifting movement axis 211, and the U-arm rotation movement axis 221, and to read the status of the bed forward and backward movement zero position sensor 112, the bed lifting zero position sensor 122, the bed rotation zero position sensor 132, the U-arm lifting zero position sensor 212, and the U-arm rotation zero position sensor 222;

[0071] The host computer control module is used to execute the automatic change-finding process, task management, and status feedback of steps 1 to 7.

[0072] The control system is designed in layers, with the host computer responsible for business process scheduling and the motion controller responsible for underlying control and sensor acquisition, ensuring the stable execution of the entire zero-finding logic.

[0073] In some embodiments, the host computer control module has a built-in safety management unit. The safety management unit is used to switch to the non-zeroing safety mode when the whole machine starts the zeroing task, disable the standard anti-collision algorithm, load the triple motion constraints of each motion axis, and generate an interference-free zeroing sequence according to the mechanical dependency relationship between each motion axis. It can centrally realize the switching of safety mode, the loading of motion constraints and the generation of interference-free zeroing sequence.

[0074] In summary, the automatic zeroing method and system for multi-axis medical imaging equipment provided by this invention can adapt to various initial parking conditions of axes. It improves the zero-point calibration accuracy through coarse-fine two-level search and error compensation, solves the interference risk when there is no absolute coordinate when powered on by the non-zeroing safety mode, and realizes automatic generation of zeroing sequence, thereby improving the automation level and operational safety of multi-axis medical imaging equipment calibration.

[0075] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An automatic zeroing method for multi-axis medical imaging equipment, characterized in that, Multi-axis medical imaging equipment includes several bed motion axes and several U-arm motion axes. Each motion axis is equipped with an independent driver and an independent zero-position sensor. The automatic zeroing method includes the following steps: Step 1: Start the automatic zeroing process of the target motion axis and perform system initialization checks; Step 2: Obtain the real-time working status of the zero-position sensor corresponding to the motion axis to be calibrated; Step 3: Determine if the zero-position sensor is currently in a triggered state: If it is determined that the zero-position sensor has been triggered, the motion axis is controlled to exit the effective area of ​​the sensor, and the sensor release process is executed to restore the zero-position sensor to a stable, untriggered state. If it is determined that the zero-position sensor has not been triggered, the motion axis is controlled to perform a limited-distance reverse probe to determine whether the motion axis has crossed the sensor area. If the sensor area is not crossed, the sensor area is searched along the preset direction at the first speed to perform coarse search and positioning. If the motion axis has already crossed the sensor area, adjust the direction of motion of the motion axis and then perform coarse search and positioning. Step 4: Control the motion axis to approach the sensor signal transition edge along a fixed direction at a second speed, perform fine search and positioning, and obtain the reference edge position of the sensor level switching. The first speed is greater than the second speed. If an abnormal situation occurs during operation, trigger the error reporting program and terminate the current motion axis zeroing. Step 5: Based on mechanical design offset, assembly error, and calibration results, perform compensation calculations on the reference edge position to obtain the theoretical zero-point coordinates; Step 6: The theoretical zero-point coordinates are written into the controller to complete the zero-point locking. Then, the zero-point coordinates are verified. If the verification is successful, the current motion axis has completed zero finding. Step 7: Perform steps 1 to 6 above on all motion axes in sequence according to the preset zeroing execution sequence. After all motion axes have been zeroed and verified, a unified mechanical coordinate system for the whole machine is established, and the automatic zeroing process of the whole machine ends.

2. The automatic zeroing method for multi-axis medical imaging equipment according to claim 1, characterized in that, In step 1, the system initialization check items include at least the controller status, motion axis status, driver status, emergency stop status, IO signals, and safety conditions.

3. The automatic zeroing method for multi-axis medical imaging equipment according to claim 1, characterized in that, In step 1, if the initialization check fails, an error reporting procedure is triggered and the automatic change-making process is terminated.

4. The automatic zeroing method for multi-axis medical imaging equipment according to claim 1, characterized in that, In step 4, abnormal situations include at least running timeout, sensor failure, and excessive motion range.

5. The automatic zeroing method for multi-axis medical imaging equipment according to claim 1, characterized in that, When the automatic zeroing process is started for the first time, the machine switches to the non-zeroing safety mode. After the unified mechanical coordinate system of the whole machine is established, it exits the non-zeroing safety mode. During the operation of the non-zeroing safety mode, the following control strategies are implemented: Disable the standard collision avoidance algorithm based on positive kinematics and absolute coordinates; Each motion axis satisfies the triple motion limits of maximum speed, maximum distance, and maximum time. Based on the mechanical dependencies of each motion axis pre-stored in the system, the zero-finding execution sequence is automatically generated.

6. The automatic zeroing method for multi-axis medical imaging equipment according to claim 5, characterized in that, The motion of each motion axis in steps 1 to 6 satisfies the triple motion constraint.

7. The automatic zeroing method for multi-axis medical imaging equipment according to claim 5, characterized in that, After exiting the non-zeroing safety mode, the standard collision avoidance algorithm is enabled.

8. An automatic zeroing control system for multi-axis medical imaging equipment, characterized in that, The automatic zeroing method for multi-axis medical imaging equipment according to any one of claims 1 to 7 includes a motion controller and a host computer control module. The motion controller is used to control the driver to control the movement of each motion axis and to read the status of the zero-position sensor; The host computer control module is used to execute the automatic change-finding process, task management, and status feedback of steps 1 to 7.

9. The automatic zeroing control system for multi-axis medical imaging equipment according to claim 8, characterized in that, The host computer control module has a built-in safety management unit. The safety management unit is used to switch to the non-zeroing safety mode when the whole machine starts the zeroing task, disable the standard anti-collision algorithm, load the triple motion limit of each motion axis, and generate an interference-free zeroing sequence according to the mechanical dependency relationship between each motion axis.

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