Multi-axis Cooperative Motion Control Method and Device for Dynamic Hovering Arc Radiotherapy Equipment

Abstract

This application discloses a multi-axis coordinated motion control method and apparatus for a dynamic hovering arc radiotherapy device, relating to the field of equipment control, and particularly to the field of radiotherapy equipment control. The method includes: acquiring the actual position information of multiple execution axes; determining the target control state of the multiple execution axes at the current moment based on the preset target motion trajectory and the actual position information; when the target control state is a linked motion state, controlling the multiple execution axes to perform coordinated motion according to the target motion trajectory; when the target control state is a coordinated locking state, controlling at least one first execution axis among the multiple execution axes to enter a position locking mode, and controlling at least one second execution axis among the multiple execution axes to enter a position maintenance mode. This application solves the technical problem of low multi-axis synchronization accuracy in existing multi-axis coordinated devices (such as dynamic arc radiotherapy devices) during dynamic hovering.

Description

Technical Field

[0001] This application relates to the field of equipment control, and more particularly to the field of radiotherapy equipment control. Specifically, it relates to a multi-axis coordinated motion control method and apparatus for dynamic hovering arc radiotherapy equipment. Background Technology

[0002] In existing multi-axis equipment control methods, software-level control point densification optimization or segmented arc illumination optimization methods are usually used to achieve dynamic hovering effects. However, when dealing with speed changes due to inertial loads, this method is prone to technical problems such as low synchronization accuracy between multiple axes during dynamic hovering due to insufficient coordination and consistency in the coordinated motion control between multiple axes.

[0003] For example, in volumetric modulated arc therapy (VMAT), the equipment needs to achieve precise irradiation of specific anatomical angles while moving continuously. However, it is difficult to achieve high-precision coordinated positioning between multiple execution axes responsible for gantry rotation, treatment head movement, and multi-leaf collimator adjustment during the switching moments and hovering maintenance phases of the dynamic hovering process.

[0004] There is currently no effective solution to the above problems. Summary of the Invention

[0005] This application provides a multi-axis coordinated motion control method and apparatus for a dynamic hovering arc radiotherapy device, to at least solve the technical problem of low multi-axis synchronization accuracy in existing multi-axis coordinated devices (such as dynamic arc radiotherapy devices) during dynamic hovering.

[0006] According to one aspect of this application, a multi-axis coordinated motion control method for a dynamic hovering arc radiotherapy device is provided, comprising: acquiring actual position information of multiple execution axes; determining the target control state of the multiple execution axes at the current moment based on the preset target motion trajectory and actual position information for the multiple execution axes, wherein the target control state includes at least a linkage motion state and a coordinated locking state; when the target control state is a linkage motion state, controlling the multiple execution axes to perform coordinated motion according to the target motion trajectory; when the target control state is a coordinated locking state, controlling at least one first execution axis among the multiple execution axes to enter a position locking mode, and controlling at least one second execution axis among the multiple execution axes to enter a position maintenance mode, so as to perform multi-axis coordinated positioning operation at a target spatial position; wherein the position maintenance mode represents, under the premise of locking the basic position of the second execution axis, controlling the spatial position of the second execution axis to remain stable or to perform controlled adjustment within a preset adjustment range, the controlled adjustment being used to compensate for mechanical hysteresis or thermal deformation errors.

[0007] Optionally, the plurality of execution axes include at least a gantry rotation axis and N other rotation axes, wherein the N other rotation axes include at least one of the following: treatment head rotation axis, collimator rotation axis, multi-leaf grating axis, and patient support bed axis, and N is an integer greater than or equal to 1.

[0008] Optionally, the linkage motion state is a continuous rotating arc motion state, and the target motion trajectory is a dynamic hovering arc radiotherapy trajectory based on the gantry rotation angle; the collaborative locking state is a dynamic hovering locking state, and the target spatial position is a spatial position determined based on a preset hovering angle.

[0009] Optionally, when the target control state is a linked motion state, controlling multiple execution axes to perform coordinated motion according to the target motion trajectory includes: when the target control state is a linked motion state, generating a target state corresponding to each execution axis in a discrete time series based on the target motion trajectory and combined with a global clock source, wherein the target state at least includes the position and velocity of each execution axis at any time in the discrete time series; determining the feedforward control quantity required to drive each execution axis to achieve the target state based on the target state corresponding to each execution axis and the dynamic model corresponding to each execution axis, wherein the dynamic model is at least used to compensate for the nonlinear friction force of the frame, adjust the speed of the execution axis, and adjust the real-time radiation dose; and controlling multiple execution axes to perform coordinated motion according to the target motion trajectory based on the feedforward control quantity.

[0010] Optionally, controlling multiple actuator axes to perform coordinated motion according to the target motion trajectory based on the feedforward control quantity includes: synchronously acquiring the actual state of each actuator axis in each control cycle; comparing the actual state of each actuator axis with the target state at the corresponding time point, determining the independent tracking error of each actuator axis based on the comparison result, and determining the inter-axis synchronization error based on the motion coupling relationship between the multiple axes; generating a closed-loop feedback correction quantity based on the independent tracking error and the inter-axis synchronization error to simultaneously correct the error of each actuator axis and maintain the inter-axis coordinated relationship; synthesizing the feedforward control quantity and the closed-loop feedback correction quantity to obtain the coordinated drive command for each actuator axis; and synchronously sending the coordinated drive command to the driver of each actuator axis through a communication bus according to the discrete time sequence, so as to control multiple actuator axes to perform coordinated motion according to the target motion trajectory.

[0011] Optionally, based on the preset target motion trajectories for multiple execution axes and combined with a global clock source, a target state corresponding to each execution axis in a discrete time series is generated, including: when the multiple execution axes include at least a rack rotation axis and N other rotation axes besides the rack rotation axis, the rack rotation axis is taken as the master axis and the N other rotation axes are taken as slave axes; combined with the global clock source, at least one target position corresponding to each slave axis on the target motion trajectory of the master axis is determined, wherein each target position corresponds to a time point in the discrete time series; and the target object corresponding to each execution axis in the discrete time series is determined based on the at least one target position.

[0012] Optionally, when the collaborative locking state is a dynamic hovering locking state, the position locking mode is used to use the rack rotation axis as the first actuating axis and maintain the angle of the rack rotation axis at a preset hovering angle through closed-loop control; the position maintenance mode includes: a locking control mode or a restricted fine-tuning control mode; wherein, the locking control mode is used to control the second actuating axis to maintain at the measured position when the second actuating axis enters the measured position in the dynamic hovering locking state; the restricted fine-tuning control mode is used to constrain the second actuating axis to make dynamic adjustments within a preset adjustment range based on the current locked position, so as to compensate for mechanical hysteresis or thermal deformation errors, and the second actuating axis is a rotation axis other than the rack rotation axis.

[0013] Optionally, when the rack rotating shaft enters the position locking mode, inertia compensation calculation is performed based on the real-time load inertia and speed change rate of the rack rotating shaft, and a target torque command is generated according to the result of the inertia compensation calculation. The target torque command is used to suppress low-speed vibration and positioning drift of the rack rotating shaft, and low-speed vibration is used to characterize the vibration caused by the rack rotating shaft running at a speed lower than the preset speed.

[0014] Optionally, based on the preset target motion trajectory and actual position information for multiple execution axes, the target control state of multiple execution axes at the current moment is determined, including: comparing the position of at least one main execution axis in the actual position information with the preset state switching point in the target motion trajectory; when the position of the main execution axis reaches the preset state switching point, the control state is triggered to switch from the linkage motion state to the cooperative locking state, or from the cooperative locking state to the linkage motion state.

[0015] Optionally, the process of multiple execution axes switching from a cooperative locked state to a linked motion state includes a lock release state, wherein, in the lock release state, the controller smoothly reconstructs the synchronization reference relationship between each execution axis, and controls the acceleration of each execution axis based on the synchronization reference relationship to restore cooperative motion.

[0016] Optionally, multiple deviation indicators of each of the multiple execution axes during operation are monitored in real time, wherein the multiple deviation indicators include at least position deviation, speed deviation and synchronization error; if any deviation indicator is detected to exceed a preset safety threshold, a safety control command is triggered, wherein the safety control command is used to implement limit control, emergency stop or safety degradation control of the execution axis.

[0017] According to another aspect of the embodiments of this application, a multi-axis cooperative motion control device for a dynamic hovering arc radiotherapy device is also provided, comprising: multiple execution axes associated with the dynamic hovering arc radiotherapy device; and a controller communicatively connected to the multiple execution axes. The controller is configured to collect actual position information of the multiple execution axes, and based on a preset target motion trajectory and actual position information for the multiple execution axes, determine the target control state of the multiple execution axes at the current moment. The target control state includes at least a linkage motion state and a cooperative locking state. The controller is further configured to control the multiple execution axes to perform cooperative motion according to the target motion trajectory when the target control state is a linkage motion state; and to control at least one first execution axis among the multiple execution axes to enter a position locking mode and control at least one second execution axis among the multiple execution axes to enter a position maintenance mode when the target control state is a cooperative locking state, so as to perform multi-axis cooperative positioning at a target spatial position. The position maintenance mode represents controlling the spatial position of the second execution axis to remain stable or to be controlled within a preset adjustment range, provided that the basic position of the second execution axis is locked. The controlled adjustment is used to compensate for mechanical hysteresis or thermal deformation errors.

[0018] Optionally, the controller integrates a hovering lock state machine module, which manages the switching of control states, including linkage motion state, cooperative locking state, and lock release state.

[0019] Optionally, the plurality of execution axes include at least a gantry rotation axis and N other rotation axes, wherein the N other rotation axes include at least one of the following: treatment head rotation axis, collimator rotation axis, multi-leaf grating axis, and patient support bed axis, and N is an integer greater than or equal to 1.

[0020] Optionally, the first actuating axis is the rack rotation axis, and the second actuating axis is an actuating axis other than the rack rotation axis among multiple actuating axes.

[0021] Optionally, the device further includes a position feedback unit, which is disposed on each actuator axis and communicates with the controller to provide the actual position information of each actuator axis.

[0022] Optionally, the controller is connected to the servo drives and position feedback units on each actuation axis via a communication bus.

[0023] Optionally, the device also includes a safety monitoring module for monitoring the operating status of multiple execution axes and triggering a protection action when any execution axis is detected to be malfunctioning. The protection action is at least used to stop the movement of all execution axes when any execution axis is malfunctioning.

[0024] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, which stores a computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located executes the above-described multi-axis cooperative motion control method for a dynamic hovering arc radiotherapy device.

[0025] According to another aspect of the embodiments of this application, an electronic device is also provided, including one or more processors and a memory, the memory being used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to perform the above-described multi-axis cooperative motion control method for a dynamic hovering arc radiotherapy device.

[0026] According to another aspect of the embodiments of this application, a computer program product is also provided, including a computer program or instructions, which, when executed by a processor, implement the above-described multi-axis coordinated motion control method for a dynamic hovering arc radiotherapy device.

[0027] In this embodiment, the controller first acquires real-time and accurate motion feedback by collecting the actual position information of multiple actuator axes. Furthermore, based on the preset target motion trajectory and the actual position information, the controller dynamically determines the target control state of the multiple actuator axes at the current moment. The target control state includes at least a linked motion state and a cooperative locking state, transforming dynamic hovering from a difficult-to-control transient process into a stable control state that can be clearly managed and maintained, namely, the cooperative locking state. When the target control state is the linked motion state, the controller can control multiple actuator axes to move cooperatively according to the target motion trajectory, corresponding to high-precision linked control during the continuous rotation phase of the device. When the target control state switches to the cooperative locking state, the controller implements differentiated control strategies for different actuator axes: controlling at least one first actuator axis to enter a position locking mode and controlling at least one second actuator axis to enter a position maintaining mode. The position locking mode can precisely stabilize the first actuator axis at a preset position. The position maintaining mode can maintain the spatial positional relationship of the second actuator axis.

[0028] The controller in this application embodiment can change the simple method of achieving "hovering" by simply setting the speed command to zero in related technologies. Traditional methods are prone to synchronization deviations and vibrations near low or zero speeds due to differences in the dynamic response characteristics of each axis, inertia differences, and control loop delays. The controller in this application embodiment introduces a cooperative locking state and assigns corresponding position locking and position maintenance modes to different execution axes under this cooperative locking state. This allows all execution axes to enter a unified control mode centered on position maintenance during hovering, which helps to suppress drift or oscillation caused by independent control of each execution axis. It promotes closer cooperative positioning of multiple axes in the target space, improves the multi-axis synchronization accuracy during dynamic hovering, and thus solves the technical problem of low multi-axis synchronization accuracy in existing multi-axis cooperative devices (such as dynamic arc radiotherapy devices) during dynamic hovering. Attached Figure Description

[0029] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0030] Figure 1 This is a flowchart of an optional multi-axis coordinated motion control method for a dynamic hovering arc radiotherapy device according to an embodiment of this application;

[0031] Figure 2 This is a schematic diagram of an optional multi-axis coordinated motion control device for a dynamic hovering arc radiotherapy device according to an embodiment of this application. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0033] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0034] According to an embodiment of this application, an embodiment of a multi-axis coordinated motion control method for a dynamic hovering arc radiotherapy device is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0035] It should be noted that the information collected in this application (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for display, data used for analysis, etc.) are information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, storage, use, processing, transmission, provision, disclosure, and application of this data all comply with relevant laws, regulations, and standards, necessary confidentiality measures have been taken, and they do not violate public order and good morals. Corresponding access points are provided for users to choose to authorize or refuse. For example, interfaces are set up between this system and relevant users or organizations, providing users with corresponding access points to choose to agree to or refuse automated decision-making results; if the user chooses to refuse, the process proceeds to the expert decision-making stage.

[0036] According to the embodiments of this application, a controller can be used as the execution subject of the multi-axis coordinated motion control method for dynamic hovering arc radiotherapy equipment in the embodiments of this application. Those skilled in the art should know that this application does not particularly limit the specific form of the execution subject of the method.

[0037] In existing multi-axis equipment control methods, dynamic hovering effects are typically achieved using software-level control point densification optimization or segmented arc irradiation. Control point densification optimization achieves this by artificially increasing the number of control points at specific angles during volumetric intensity-modulated radiotherapy (IMRT) planning. However, due to the mechanical inertia of the hardware system, it is prone to mechanical oscillations during frequent frequency and speed adjustments, and the dynamic response of the multi-leaf grating is difficult to perfectly match with changes in gantry speed. While segmented arc irradiation can achieve pauses at specific angles, significant hardware feedback delays during gantry start-stop-start switching not only reduce treatment efficiency but also easily lead to unstable dose output.

[0038] Figure 1 This is a flowchart of a multi-axis coordinated motion control method for a dynamic hovering arc radiotherapy device according to an embodiment of this application, such as... Figure 1 As shown, the method includes the following steps:

[0039] Step S101: Collect the actual position information of multiple execution axes, which are execution axes related to the dynamic hovering arc radiotherapy device.

[0040] Optionally, the actual position information of multiple actuators can be characterized as a continuous signal or digital quantity that reflects the angular or linear displacement of the actuator in space, obtained directly by physical sensors such as encoders and grating rulers.

[0041] Optionally, the actual position information of multiple actuator axes can be acquired through position feedback units installed on each actuator axis. For example, the position feedback unit can, but is not limited to, employ a high-resolution absolute encoder. A high-resolution absolute encoder can provide microradian-level angular resolution and micrometer-level linear resolution, thus providing continuous and stable position information during high-speed rotation and hovering. This provides precise position signals for closed-loop control and state judgment, and high-speed, high-precision position feedback helps achieve high-precision motion control. The position feedback signal from the position feedback unit can be transmitted to the controller via a communication bus. The communication bus can be a high-speed synchronous bus, such as an EtherCAT (Ethernet for Control Automation Technology) bus or a fiber optic ring network. Transmission via a communication bus provides high-bandwidth, low-latency communication, which is beneficial for ensuring high-speed synchronous transmission of control commands and feedback signals, achieving sub-millisecond multi-axis synchronization.

[0042] By acquiring the real spatial state of multiple execution axes at any given time, it is beneficial to provide real-time and accurate feedback input, enabling the controller to make decisions based on the actual physical state of multiple execution axes rather than an ideal model.

[0043] Step S102: Based on the preset target motion trajectory and actual position information for multiple execution axes, determine the target control state of multiple execution axes at the current moment. The target control state includes at least the linkage motion state and the cooperative locking state.

[0044] Optionally, the target motion trajectory can be represented as a pre-planned function or data sequence of time and target position, velocity, or acceleration of each execution axis, designed to complete specific tasks such as dynamic hovering arc radiotherapy. The target control state can be represented as a logical identifier determined by the controller's internal state machine based on the planned trajectory and real-time feedback, used to guide the control mode of each execution axis in the next control cycle.

[0045] Optionally, the target control state includes at least a linked motion state and a cooperative locking state. The linked motion state corresponds to scenarios where the execution axes need to perform continuous cooperative motion according to a preset target motion trajectory, such as continuous rotating arcs in radiotherapy. The cooperative locking state corresponds to scenarios where the execution axes need to maintain cooperative positioning at a specific spatial location, such as the hovering phase in dynamic hovering arc radiotherapy. The controller can integrate a high-performance processing unit and a hovering-locking state machine module. The processing unit can receive angle or displacement information of each execution axis collected by the position feedback unit and compare the collected angle or displacement information with the preset target motion trajectory and timestamp to calculate the deviation. The hovering-locking state machine module is used to manage the switching of control states, which helps ensure that the control state matches the motion phase, improving the system's response accuracy and stability.

[0046] For example, the target motion trajectory pre-stored in the controller can include explicit state switching points, such as state switching points corresponding to the rack reaching a specific angle. The controller compares the actual position information of the main actuator with the state switching points. When the position of the main actuator enters a preset tolerance window centered on the state switching point, the state switching logic is triggered, changing the target control state from the linkage motion state to the cooperative locking state.

[0047] For example, the switching of the target control state depends not only on the trajectory position, but also on a combination of external events and internal conditions. External events include receiving a "start hovering" command, while internal conditions may include that the tracking errors of each execution axis are below a set threshold and that the system load is stable. The hovering lock state machine module within the controller can make decisions by comprehensively considering position, external events, and internal conditions, which helps ensure that the state switching occurs when the system is stable and the conditions are met, thus improving the reliability of the switching process.

[0048] Step S103: When the target control state is the linkage motion state, control multiple execution axes to perform coordinated motion according to the target motion trajectory.

[0049] Optionally, cooperative motion can characterize the motion of multiple execution axes as not independent, but strongly coupled in time, space or velocity. With the motion of one axis as the reference, the other axes must strictly follow its changes to jointly complete a composite spatial motion.

[0050] Optionally, when the target control state is a linked motion state, the controller controls multiple actuators to move collaboratively according to a preset target motion trajectory. The controller can employ a multi-axis linkage planning algorithm, using the frame rotation axis as a virtual master axis, and calculate the corresponding target position of each slave axis on the virtual master axis's motion trajectory. The controller can issue control commands in real time through a feedforward plus closed-loop control mode, while simultaneously compensating for phase error, speed error, and mechanical hysteresis error online, thereby ensuring that each actuator moves with high synchronization and stability throughout the entire rotation process.

[0051] Step S104: When the target control state is in the cooperative locking state, control at least one first execution axis among the multiple execution axes to enter the position locking mode, and control at least one second execution axis among the multiple execution axes to enter the position maintenance mode, so as to perform multi-axis cooperative positioning operation at the target spatial position.

[0052] Optionally, the position locking mode can characterize a closed-loop control applied to a specific actuator axis. The control objective of the position locking mode can be changed from tracking a time-varying trajectory to maintaining a constant setpoint. Control algorithm parameters such as proportional and integral gain can be adjusted to focus more on anti-interference and zero steady-state error. The position holding mode can characterize allowing the actuator axis to make controlled adjustments within a small range (e.g., a preset adjustment range) while locking the basic position, in order to compensate for minor deviations or environmental changes such as thermal deformation of other axes among multiple actuator axes. The position locking mode is used to maintain the angle of the first actuator axis at a preset hovering angle.

[0053] Optionally, the position maintenance mode may include a locking control mode or a restricted fine-tuning control mode, which controls at least one second actuator among multiple actuator axes to enter the position maintenance mode, which is beneficial to maintain the spatial position stability of the second actuator (i.e., in the locking control mode, the spatial position of the second actuator is kept stable), or to make fine adjustments to compensate for mechanical hysteresis or thermal deformation errors (i.e., in the restricted fine-tuning control mode, the spatial position of the second actuator is controlled to be adjusted within a preset adjustment range to compensate for mechanical hysteresis or thermal deformation errors).

[0054] By introducing a dual-state control mechanism of linked motion state and cooperative locking state, the dynamic hovering process is transformed from the traditional "speed reduced to zero" control mode into a stable cooperative locking state, which helps to improve the multi-axis synchronization accuracy and control stability during dynamic hovering.

[0055] It should be noted that the controller in this embodiment does not simply stop all axes, but rather adopts differentiated precision control strategies for different axes, tailored to the characteristics of hovering tasks. A high-rigidity position lock is implemented for the first actuation axis, which plays a core positioning role, while a position maintenance strategy allowing for fine adjustments is implemented for the second actuation axis, which plays an auxiliary adjustment role. During hovering, the controller can maintain a stable control state in a cooperative locking state, which helps suppress low-speed vibrations, overcome nonlinear friction and load disturbances, thereby facilitating long-term, high-precision maintenance of the relative positional relationship between the actuation axes at the target spatial position and reducing synchronization misalignment caused by unsuitable control modes during hovering.

[0056] In some optional embodiments, the plurality of actuation axes include at least a gantry rotation axis and N other rotation axes, the N other rotation axes including at least one of a treatment head rotation axis, a collimator rotation axis, a multi-leaf grating axis and a patient support bed axis, where N is an integer greater than or equal to 1.

[0057] Optionally, in radiotherapy equipment applications, multiple execution axes may specifically include: a gantry rotation axis, a treatment head rotation axis, a collimator rotation axis, a multi-leaf grating axis, and a translation or rotation axis of the patient support bed. The gantry rotation axis can drive the radiation source to rotate around the patient; the treatment head and collimator axes can adjust the beam direction and shape of the radiation source; the multi-leaf grating axis can dynamically form the irradiation field; and the bed axis can position the patient. Multiple execution axes facilitate multi-degree-of-freedom coordinated motion during radiotherapy.

[0058] In some optional embodiments, the linkage motion state is a continuous rotating arc motion state, and the target motion trajectory is a dynamic hovering arc radiotherapy trajectory based on the gantry rotation angle; the cooperative locking state is a dynamic hovering locking state, and the target spatial position is a spatial position determined based on a preset hovering angle.

[0059] Optionally, the dynamic hovering arc radiotherapy trajectory can refer to a specific angle range within a continuously rotating arc-shaped treatment path, where deceleration and precise irradiation can be preset according to the treatment plan. The continuous rotating arc motion state corresponds to the stage where the gantry and associated axes rotate continuously at a preset speed for conventional irradiation.

[0060] Optionally, the dynamic hover lock state corresponds to the stage where the gantry rotation axis reaches a preset hover angle, and each actuator axis can enter a coordinated lock-up phase for high-precision dose delivery. Combining the control state with specific radiotherapy scenarios allows the control logic to better align with practical application requirements.

[0061] In some optional embodiments, when the target control state is a linked motion state, controlling multiple execution axes to perform coordinated motion according to the target motion trajectory includes: when the target control state is a linked motion state, generating a target state corresponding to each execution axis in a discrete time series based on the target motion trajectory and in conjunction with a global clock source, wherein the target state at least includes the position and velocity of each execution axis at any time in the discrete time series; determining the feedforward control quantity required to drive each execution axis to achieve the target state based on the target state corresponding to each execution axis and the dynamic model corresponding to each execution axis, wherein the dynamic model is at least used to compensate for the nonlinear friction force of the frame, adjust the speed of the execution axis, and adjust the real-time radiation dose; and controlling multiple execution axes to perform coordinated motion according to the target motion trajectory based on the feedforward control quantity.

[0062] Optionally, a global clock source can provide a unified timing reference, which helps to ensure that all control commands and feedback signals are strictly synchronized in time.

[0063] Optionally, the dynamic model may include the moment of inertia, damping coefficient, and frictional torque of the actuating shaft. By predicting through the dynamic model, feedforward control variables can provide some of the drive commands before motion occurs, compensating for the inherent dynamic characteristics of the system, such as compensating for nonlinear frictional forces on the frame and adjusting the speed of the actuating shaft, thereby helping to reduce tracking errors and adjust real-time radiation dose.

[0064] Optionally, the feedforward control quantity can represent the command quantity calculated by the controller based on the target state and dynamic model, used to pre-drive the actuator axes. The feedforward control quantity can be independent of real-time feedback errors, aiming to provide compensation before tracking errors occur. For example, the feedforward control quantity can be used to overcome the acceleration torque of system inertia or to counteract bias current caused by known friction. Controlling multiple actuator axes to move collaboratively along the target trajectory according to the feedforward control quantity helps improve the controller's ability to quickly track the preset trajectory and reduces response delay caused by system inertia.

[0065] Through feedforward compensation, the controller can respond more quickly to the tracking of the preset trajectory. Since some of the influence of the system's dynamic characteristics can be offset in advance, the relative motion relationship between each actuator axis can be more coordinated, and the synchronization error can be reduced.

[0066] In some optional embodiments, controlling multiple actuator axes to perform coordinated motion according to a target motion trajectory based on feedforward control quantities includes: the controller can synchronously collect the actual state of each actuator axis in each control cycle; compare the actual state of each actuator axis with the target state at the corresponding time point, determine the independent tracking error of each actuator axis based on the comparison result, and determine the inter-axis synchronization error based on the motion coupling relationship between multiple axes; and generate a closed-loop feedback correction quantity based on the independent tracking error and the inter-axis synchronization error to simultaneously correct the error of each actuator axis and maintain the inter-axis coordinated relationship; then synthesize the feedforward control quantity and the closed-loop feedback correction quantity to obtain the coordinated drive command for each actuator axis; and synchronously send the coordinated drive command to the driver of each actuator axis through a communication bus according to the discrete time sequence, so as to control multiple actuator axes to perform coordinated motion according to the target motion trajectory.

[0067] Optionally, the actual state of each actuator axis may include the actual position and actual speed obtained through the position feedback unit. By synchronously acquiring and comparing data, the controller can achieve real-time perception of motion deviations.

[0068] Optionally, independent tracking error can characterize the deviation between the actual state of a single actuator axis and its corresponding target state. For example, independent tracking error can include position tracking error and velocity tracking error. Inter-axis synchronization error can refer to the coordinated deviation caused by kinematic coupling such as geometric linkage and velocity proportional relationship between multiple actuator axes. Inter-axis synchronization error does not focus on the absolute error of a single axis, but rather on whether the relative position or velocity relationship of multiple axes is coordinated. For example, the angular error formed when the angular difference between two axes that should rotate synchronously exceeds the allowable range. By jointly considering independent tracking error and inter-axis synchronization error, controller calibration can not only improve single-axis accuracy but also maintain the coordinated relationship between multiple axes, helping to reduce synchronization delay in multi-axis linkage.

[0069] Optionally, the closed-loop feedback correction can characterize the compensation command calculated by the controller through feedback control based on real-time errors such as independent tracking error and inter-axis synchronization error. The closed-loop feedback correction can correct motion deviations caused by model inaccuracies, external disturbances, or parameter changes online in real time. For example, the closed-loop feedback correction can be calculated using control algorithms such as proportional-integral-derivative (PI-DI) control or sliding mode control. The synthesis method for combining the feedforward control quantity and the closed-loop feedback correction quantity can be numerical addition.

[0070] Optionally, the cooperative drive command can characterize the complete control command ultimately sent to the actuator axis driver. The cooperative drive command can be the result of synthesizing the feedforward control quantity and the closed-loop feedback correction quantity, and can include both a forward-looking drive part based on model prediction and a corrective drive part based on real-time error.

[0071] Optionally, the collaborative drive instructions can be synchronously sent to the driver of each execution axis via a communication bus. This can refer to sending instructions with a unified timestamp via a high-speed bus, which can achieve sub-millisecond instruction synchronization.

[0072] The controller in this embodiment helps to quickly respond to changes in the preset trajectory through feedforward control, and helps to correct deviations caused by various disturbances in real time through closed-loop feedback. Combining feedforward control and closed-loop feedback correction to work together can form a dual-loop control structure of feedforward plus closed-loop, which is beneficial to improving the accuracy of multi-axis coordinated motion.

[0073] In some optional embodiments, based on the preset target motion trajectory for multiple execution axes and combined with a global clock source, a target state corresponding to each execution axis in a discrete time series is generated. This includes: the controller can, when the multiple execution axes include at least the rack rotation axis and N other rotation axes besides the rack rotation axis, take the rack rotation axis as the master axis and the N other rotation axes as slave axes; and, combined with the global clock source, determine at least one target position corresponding to each slave axis on the target motion trajectory of the master axis, wherein each target position corresponds to a point in time in the discrete time series; and then determine the target object corresponding to each execution axis in the discrete time series based on the at least one target position.

[0074] Optionally, the specific method for generating the target state corresponding to each execution axis on the discrete time series adopts a virtual master axis planning mechanism. The gantry rotation axis is used as the master axis, and the other N rotation axes are used as slave axes because, in dynamic arc radiotherapy, the rotation angle of the gantry rotation axis is a core parameter of the treatment plan, and the movements of the other axes need to match the rotation angle of the gantry rotation axis.

[0075] Optionally, the target position can represent the desired spatial coordinate or angle value planned by the controller for a certain execution axis at a specific point in time in a discrete time series. For the target angle of the master axis at each discrete point in time, the target angle or position that the slave axes such as the treatment head rotation axis and the collimator rotation axis should have at that moment can be determined by pre-calculation or real-time table lookup.

[0076] Optionally, the target object can be characterized as a set of complete target state data generated for each execution axis in a discrete time series. The target object includes not only a series of target positions, but also information such as the corresponding target velocity and target acceleration obtained by differentiating or programming the position sequence, which is used to describe the desired motion process of the execution axis.

[0077] Employing a virtual master-spindle planning mechanism, which uses the gantry rotation axis as the primary reference to uniformly plan the motion of all slave axes, simplifies the complexity of multi-axis trajectory planning and helps ensure high temporal and spatial coordination among all execution axes. Combining a global clock source to determine the corresponding position at each time point facilitates strict alignment of motion commands across all execution axes in the temporal dimension, enabling high-precision synchronous motion. Generating a complete target object based on at least one target position facilitates efficient calculation of the target state and accurate acquisition of feedforward control quantities. This master-spindle planning approach is beneficial in scenarios such as dynamic hovering arc radiotherapy, ensuring that slave axes such as the treatment head and collimator accurately follow the gantry's rotation and hovering, maintaining spatial dose delivery geometry.

[0078] In some optional embodiments, the controller can, when the cooperative locking state is in a dynamic hovering locking state, use a position locking mode to use the rack rotation axis as the first actuation axis and maintain the angle of the rack rotation axis at a preset hovering angle through closed-loop control; the position maintenance mode includes: a locking control mode or a restricted fine-tuning control mode; wherein, the locking control mode is used to control the second actuation axis to maintain at the measured position when the second actuation axis enters the measured position in the dynamic hovering locking state; the restricted fine-tuning control mode is used to constrain the second actuation axis to make dynamic adjustments within a preset adjustment range based on the current locked position to compensate for mechanical hysteresis or thermal deformation errors, and the second actuation axis is a rotation axis other than the rack rotation axis.

[0079] Optionally, the preset hovering angle can represent the target rotation angle pre-set for the gantry rotation axis in a dynamic hovering arc radiotherapy plan, when fine dose delivery or irradiation in a specific direction is required. This preset hovering angle can serve as a reference for triggering the cooperative locking state and initiating the position locking mode. The closed-loop control can continuously receive position feedback, calculate the deviation from the preset hovering angle, and output control torque to eliminate the deviation, thereby locking the gantry at the target angle.

[0080] Optionally, the locking control mode is used to maintain the second actuator at the measured position when it enters the dynamic hover lock state. For example, when the treatment head rotation axis reaches the actual angle at the hover moment, the controller instructs its driver to maintain that position without making any active adjustments. The measured position can characterize the spatial coordinates or angle value of a certain second actuator actually measured by the position feedback unit at the precise moment when the controller triggers the entry into the dynamic hover lock state. This measured position is used as the setpoint for the locking control mode.

[0081] Optionally, the constrained fine-tuning control mode is used to constrain the second actuator axis to make dynamic adjustments within a preset range based on its current locked position, in order to compensate for mechanical hysteresis or thermal deformation errors. The second actuator axis is a rotational axis other than the gantry rotation axis, such as the collimator rotation axis or the patient support bed rotation axis. During the hovering phase, the position of the second actuator axis may drift slightly due to thermal effects or mechanical stress relaxation. The constrained fine-tuning control mode allows the controller to actively adjust the second actuator axis within a very small positional range (e.g., ±0.1 degrees) to compensate for the drift and ensure the accuracy of the multi-axis spatial relationship.

[0082] Alternatively, mechanical hysteresis or thermal deformation error can characterize the slowly changing, nonlinear deviation between the actual position and the theoretical commanded position of the actuator axis in a multi-axis precision mechanical system, caused by factors such as elastic deformation and clearance of transmission components like gears and bearings, as well as thermal expansion of materials. This error may become significant when maintaining a fixed posture for extended periods, such as during hovering.

[0083] During the hovering phase, the position feedback unit continuously collects angle or displacement data from each actuator axis. This data is used by the hovering lock state machine for locking control and minor corrections to eliminate errors caused by mechanical hysteresis or vibration, ensuring precise and stable spatial positional relationships between the multiple axes under high-speed coordination. A position locking mode is designed for the gantry rotation axis, helping to maintain it precisely and stably at the preset hovering angle, which is beneficial for achieving precise directional irradiation. Two options are provided for the second actuator axis: a locking control mode and a restricted fine-tuning control mode, increasing the system's flexibility in handling different scenarios. The locking control mode can meet the needs of scenarios requiring simple position holding, with simple and reliable control logic. The restricted fine-tuning control mode provides an active compensation mechanism for unavoidable slow time-varying errors such as thermal deformation in high-precision, long-term hovering scenarios. This helps to continuously maintain the spatial geometric accuracy requirements between the multiple axes throughout the entire hovering period, thereby improving the accuracy and consistency of the final dose delivery distribution.

[0084] In some optional embodiments, when the rack rotating shaft enters the position locking mode, the controller can perform inertia compensation calculation based on the real-time load inertia and speed change rate of the rack rotating shaft, and generate a target torque command based on the result of the inertia compensation calculation. The target torque command is used to suppress low-speed vibration and positioning drift of the rack rotating shaft, and low-speed vibration is used to characterize the vibration caused by the rack rotating shaft running at a speed lower than a preset speed.

[0085] Optionally, an inertial compensation mechanism can be introduced to address the low-speed vibration that may occur when the gantry rotation axis enters the position-locked mode. The real-time load inertia can be estimated in real time based on the gantry's structural parameters and additional loads such as the treatment head. The rate of change of speed characterizes the deceleration of the gantry during its deceleration to a hovering state. Low-speed vibration characterizes the vibration caused by the gantry rotation axis operating at speeds below a preset threshold; low-speed vibration may originate from nonlinear friction, gear backlash, etc.

[0086] Optionally, the inertia compensation calculation can be based on Newton's second law or the law of rotational motion to estimate the inertial torque generated during velocity changes to overcome the huge rotational inertia of the frame's rotating shaft. The controller can then generate an additional target torque command based on the results of the inertia compensation calculation.

[0087] Optionally, during deceleration, the controller can pre-calculate a compensating torque opposite to the direction of motion to counteract the overshoot tendency caused by the huge rotational inertia of the frame. After entering the extremely low-speed range, the controller can feed forward a chattering torque to overcome static friction based on the friction model, or use a high-frequency, small-amplitude torque command to activate and smooth the transition of friction force, thereby suppressing the creeping phenomenon.

[0088] Inertial compensation mechanisms help address the transient transition of large-inertia gantry frames from high-speed rotation to near-stationary states, improving stability during low-speed operation. Through high-precision multi-axis linkage motion control and dynamic hovering control mechanisms, using the gantry rotation axis as a virtual master axis, multi-axis trajectories are planned uniformly. Controllable "deceleration-hovering-re-acceleration" intervals are inserted into continuous rotation, and high-precision synchronization is achieved through high-resolution feedback and real-time compensation. This facilitates microsecond-level high-precision linkage and coordination of "velocity-position-dose" during dynamic hovering of large-inertia gantry frames.

[0089] In some optional embodiments, the target control state of multiple execution axes at the current moment is determined based on the preset target motion trajectory and actual position information for multiple execution axes, including: the controller can compare the position of at least one main execution axis in the actual position information with the preset state switching point in the target motion trajectory; when the position of the main execution axis reaches the preset state switching point, the control state is triggered to switch from the linkage motion state to the cooperative locking state, or from the cooperative locking state to the linkage motion state.

[0090] Optionally, the position of the main actuator axis can correspond to the real-time angle of the rack rotation axis, which serves as the system motion reference. The preset state switching point can refer to the key location point on the target motion trajectory where the marked control mode needs to be changed, such as the "deceleration start point" and "hover start point" for transitioning from continuous rotation to hover, and the "release start point" for resuming rotation from hover.

[0091] Optionally, when the controller determines through comparison that the main actuator position has reached (or exceeded within tolerance) a preset state switching point, the controller can generate a trigger signal. This trigger signal can be used to command the hover-lock state machine module to perform a state switch. The direction of the state switch can be either a control state switching from a linked motion state to a cooperative locking state, or a control state switching from a cooperative locking state to a linked motion state. The specific switching direction depends on the specific stage transition intention represented by the triggered preset state switching point. For example, triggering the "hover-lock point" can cause the control state to switch from a linked motion state to a cooperative locking state; while triggering the "release start point" can cause the control state to switch from a cooperative locking state to a linked motion state. Through this triggering method based on precise matching between the actual position of the main actuator and the preset path point, the controller can accurately translate the user's planned intent into a sequence of underlying control states. Compared to time-based triggering, it can more accurately match the actual mechanical movement with the purpose of the treatment plan, helping to improve the accuracy and real-time performance of state switching.

[0092] In some optional embodiments, the process of multiple execution axes switching from a cooperative locked state to a linked motion state includes a lock release state, wherein, in the lock release state, the synchronization reference relationship between each execution axis is smoothly reconstructed by the controller, and the acceleration of each execution axis is controlled based on the synchronization reference relationship to restore cooperative motion.

[0093] Optionally, the process of multiple execution axes switching from the cooperative locking state to the linked motion state is not a direct jump, but includes an intermediate transition phase, namely the lock release state.

[0094] In the locked-release state, the controller can smoothly rebuild the synchronization reference relationship between each actuator axis. During hovering, the dynamic motion coupling relationship between the actuator axes is temporarily frozen. When motion needs to be resumed, the controller needs to recalculate and establish a new synchronization reference relationship between the actuator axes based on the current actual position of each actuator axis and the preset next motion trajectory. For example, it needs to recalculate the position-velocity mapping of the slave axis relative to the master axis.

[0095] The controller accelerates each actuator axis based on the reconstructed synchronous reference relationship to restore coordinated motion. The controller can generate smooth acceleration commands, enabling each actuator axis to smoothly accelerate from a stationary or extremely low speed state to the target speed of continuous rotation, avoiding abrupt synchronization changes or mechanical shocks during motion restoration.

[0096] Lock-out states allow for a smoother and more natural transition from hovering to re-movement, which helps protect the mechanical equipment and maintain stable dose delivery during treatment.

[0097] In some optional embodiments, the controller can monitor multiple deviation indicators of each of the multiple execution axes in real time during operation, wherein the multiple deviation indicators include at least position deviation, speed deviation and synchronization error; if any deviation indicator is detected to exceed a preset safety threshold, a safety control command is triggered, wherein the safety control command is used to implement limit control, emergency stop or safety degradation control of the execution axis.

[0098] Optionally, the multi-axis coordinated motion control method for dynamic hovering arc radiotherapy equipment also includes a safety monitoring mechanism to improve the reliability of system operation. Position deviation can represent the difference between the actual position and the target position, velocity deviation can refer to the difference between the actual velocity and the target velocity, and synchronization error can refer to the difference between the deviation of the actual positional relationship between the multiple axes and the target relationship. The safety threshold is a pre-set value based on the equipment's safe operation limits.

[0099] Optionally, the safety monitoring mechanism can be implemented by the controller regulating the safety monitoring module. For example, the safety monitoring module may include a high-precision sensing unit, a signal acquisition and processing unit, and a control interface unit. The sensing unit acquires angle, displacement, speed, and torque signals of each actuator axis in real time. The signal acquisition and processing unit compares and analyzes the acquired data in real time to determine whether any limits are exceeded. When an abnormal state is detected, the safety monitoring module sends commands to the controller and servo drive through the control interface unit, causing the rack rotation axis and each slave axis to immediately switch to safety control mode or stop moving.

[0100] The security monitoring mechanism employs redundant sensing and real-time diagnostic algorithms to improve system reliability and can record various abnormal events and status changes, which is beneficial for subsequent maintenance and quality management.

[0101] See Figure 2 According to another aspect of the embodiments of this application, a multi-axis collaborative motion control device for a dynamic hovering arc radiotherapy device is also provided, comprising: multiple execution axes and a controller associated with the dynamic hovering arc radiotherapy device, wherein the controller is communicatively connected to the multiple execution axes; wherein the controller is used to collect the actual position information of the multiple execution axes, and determine the target control state of the multiple execution axes at the current moment based on the preset target motion trajectory and the actual position information for the multiple execution axes, wherein the target control state includes at least a linkage motion state and a collaborative locking state; the controller is also used to control the multiple execution axes to perform collaborative motion according to the target motion trajectory when the target control state is a linkage motion state; and to control at least one first execution axis among the multiple execution axes to enter a position locking mode and control at least one second execution axis among the multiple execution axes to enter a position maintenance mode when the target control state is a collaborative locking state, so as to perform multi-axis collaborative positioning operation at the target spatial position.

[0102] In some optional embodiments, the controller integrates a hovering lock state machine module, which manages the switching of control states, including linked motion state, cooperative locking state, and lock release state.

[0103] The hovering lock state machine module can switch smoothly and orderly between continuous rotation and other linked motion states, hovering lock and other coordinated locking states, and hovering release and other lock release states based on preset logic rules and real-time feedback information. This helps to change the traditional control method of achieving hovering by reducing the speed to zero, and enables multiple axes to enter a unified locking control mode during hovering.

[0104] In some optional embodiments, the plurality of actuation axes include at least a gantry rotation axis and N other rotation axes, the N other rotation axes including at least one of a treatment head rotation axis, a collimator rotation axis, a multi-leaf grating axis and a patient support bed axis, where N is an integer greater than or equal to 1.

[0105] In some alternative embodiments, the first actuation axis is a rack rotation axis, and the second actuation axis is an actuation axis other than the rack rotation axis among a plurality of actuation axes.

[0106] The second execution axis is any execution axis other than the gantry rotation axis. For example, the second execution axis may include the treatment head rotation axis, the collimator rotation axis, the translation axis and / or rotation axis of the patient support bed. During hovering, locking the angle of the gantry rotation axis can be the primary objective, while other axes work in conjunction with the gantry to maintain or fine-tune the position, thereby achieving overall spatial positioning stability.

[0107] In some optional embodiments, the apparatus further includes a position feedback unit disposed on each actuation axis and communicatively connected to the controller, for providing actual position information of each actuation axis.

[0108] In some alternative embodiments, the controller is connected to the servo drives and position feedback units on each actuation axis via a communication bus.

[0109] In some optional embodiments, the apparatus further includes a safety monitoring module for monitoring the operating status of multiple execution axes and triggering a protection action when any execution axis is detected to be operating abnormally, wherein the protection action is at least used to stop the movement of all execution axes when any execution axis is operating abnormally.

[0110] The protective actions may also include limit control, emergency stop, or safety degradation control of the malfunctioning actuator and its associated actuators. The independent monitoring function of the safety monitoring module helps to take protective measures even when the controller malfunctions, thus preventing equipment damage or personal injury.

[0111] In some optional embodiments, the controller includes: a first processing unit, configured to, when the target control state is the linked motion state, generate a target state corresponding to each execution axis in a discrete time series based on the target motion trajectory and in conjunction with a global clock source, wherein the target state includes at least the position and velocity of each execution axis at any time in the discrete time series; a second processing unit, configured to, based on the target state corresponding to each execution axis and the dynamic model corresponding to each execution axis, determine the feedforward control quantity required to drive each execution axis to achieve the target state, wherein the dynamic model is at least used to compensate for the nonlinear frictional force of the frame, adjust the speed of the execution axis, and adjust the real-time radiation dose; and a third processing unit, configured to control the plurality of execution axes to perform coordinated motion according to the target motion trajectory based on the feedforward control quantity.

[0112] In some optional embodiments, the third processing unit includes: a first processing subunit, configured to synchronously acquire the actual state of each execution axis in each control cycle; compare the actual state of each execution axis with the target state at the corresponding time point, determine the independent tracking error of each execution axis based on the comparison result, and determine the inter-axis synchronization error based on the motion coupling relationship between the multiple axes; a second processing subunit, configured to generate a closed-loop feedback correction quantity for simultaneously correcting the error of each execution axis and maintaining the inter-axis cooperative relationship based on the independent tracking error and the inter-axis synchronization error; a third processing subunit, configured to synthesize the feedforward control quantity and the closed-loop feedback correction quantity to obtain the cooperative drive command for each execution axis; and a fourth processing subunit, configured to synchronously send the cooperative drive command to the driver of each execution axis through a communication bus according to the discrete time sequence, so as to control the multiple execution axes to perform coordinated motion according to the target motion trajectory.

[0113] In some optional embodiments, the first processing unit includes: a fifth processing subunit, configured to, when the plurality of execution axes include at least a rack rotation axis and N other rotation axes besides the rack rotation axis, designate the rack rotation axis as the master axis and the N other rotation axes as slave axes; a sixth processing subunit, configured to, in conjunction with the global clock source, determine at least one target position corresponding to each slave axis on the target motion trajectory of the master axis, wherein each target position corresponds to a point in time in the discrete time series; and a seventh processing subunit, configured to, based on the at least one target position, determine the target object corresponding to each execution axis in the discrete time series.

[0114] In some optional embodiments, the controller further includes: a fifth processing unit, configured to perform inertial compensation calculation based on the real-time load inertia and speed change rate of the rack rotating shaft when the rack rotating shaft enters the position locking mode, and generate a target torque command based on the result of the inertial compensation calculation, wherein the target torque command is used to suppress low-speed vibration and positioning drift of the rack rotating shaft, and the low-speed vibration is used to characterize the vibration caused by the rack rotating shaft running at a speed lower than a preset speed.

[0115] In some optional embodiments, the controller includes: a sixth processing unit, configured to compare at least one main execution axis position in the actual position information with a preset state switching point in the target motion trajectory; and a seventh processing unit, configured to trigger a control state to switch from the linked motion state to the cooperative locking state, or from the cooperative locking state to the linked motion state, when the main execution axis position reaches the preset state switching point.

[0116] In some optional embodiments, the safety monitoring module includes: an eighth processing unit, used to monitor in real time multiple deviation indicators of each of the plurality of execution axes during operation, wherein the plurality of deviation indicators include at least position deviation, speed deviation and synchronization error; and a ninth processing unit, used to trigger a safety control command when any deviation indicator is detected to exceed a preset safety threshold, wherein the safety control command is used to implement limit control, emergency stop or safety degradation control of the execution axis.

[0117] For example, a control device for multi-axis coordinated motion may include a multi-axis actuator, a position feedback unit, a controller, and a safety monitoring module.

[0118] The multi-axis actuator includes at least a gantry rotation axis, a treatment head rotation axis, a collimator rotation axis, and a translational and / or rotational axis of the patient support bed, used to achieve multi-degree-of-freedom coordinated motion during radiotherapy. The multi-axis actuator is electrically connected to the controller via a high-speed synchronization bus. The controller can be configured with a high-precision clock source as a global synchronization reference. Motion commands sent by the controller to each of the multiple actuator axes are issued according to a unified timestamp sequence, facilitating sub-millisecond-level command synchronization. The controller can employ a multi-axis linkage planning algorithm, using the gantry rotation axis as a virtual master axis, to calculate the corresponding target position of each slave axis (i.e., the actuator axis other than the gantry rotation axis) on the master axis's motion trajectory. The controller issues control commands in real time through a control mode combining feedforward control and closed-loop feedback control, while simultaneously performing online compensation for phase error, velocity error, and mechanical hysteresis error during motion. This helps ensure that each actuator axis maintains high synchronization and smooth movement throughout the continuous rotational motion and hovering locking process, facilitating high-speed coordination among multiple actuator axes.

[0119] Position feedback units are installed on each actuator axis to collect angle and / or displacement information of the corresponding actuator axis in real time. Each position feedback unit can employ a high-resolution absolute encoder, which is electrically connected to the servo driver or motion controller of the corresponding actuator axis, facilitating real-time acquisition of the angle or displacement of each actuator axis. High-resolution absolute encoders can have microradian-level angle resolution and micron-level linear resolution, contributing to providing continuous and stable position information during high-speed rotation and hovering / locking. The position feedback signals collected by the position feedback units are transmitted to the controller via a high-speed digital bus. The controller uses a global high-precision clock as a synchronization reference, compares the feedback information of each actuator axis with the preset motion trajectory in real time, and corrects errors using a control algorithm combining feedforward control and closed-loop feedback control. This helps ensure the synchronization accuracy and operational stability of each actuator axis in continuous rotation, hovering / locking, and hovering / release states. In the hovering / locking state, the position feedback units continuously collect angle or displacement data of each actuator axis. The angle or displacement data of each actuator axis can be used by the hovering lock state machine module inside the controller for position locking control and micro-correction, in an attempt to reduce or eliminate errors caused by mechanical lag or vibration. This helps to maintain the precise and stable spatial positional relationship of multiple actuator axes under high-speed coordination, and achieves the precise positioning requirements of multiple degrees of freedom of the treatment head, collimator and patient support bed during dynamic hovering arc radiotherapy.

[0120] The controller can be electrically connected to multi-axis actuators and position feedback units for unified motion trajectory planning and synchronous motion control of each actuator axis. Internally, the controller includes a hover-lock state machine module. This module includes at least three states: continuous rotation, hover-lock, and hover-release, and is used to manage the motion control state during arc radiotherapy. When the hover-lock state machine module is in continuous rotation, each actuator axis can perform synchronous motion control according to a preset linkage relationship. When the hover-lock state machine module switches to hover-lock, the gantry rotation axis switches from conventional motion control mode to angle-lock control mode, while the remaining actuator axes switch from linkage-following control mode to lock control mode or restricted fine-tuning control mode to achieve multi-axis synchronous position locking during dynamic hovering. When the hover-lock state machine module switches to hover-release, the controller smoothly reconstructs the synchronization reference relationship between each actuator axis and smoothly restores each actuator axis to continuous rotation. The hovering lock state machine module defines the dynamic hovering process as a stable operating state of the controller, which is conducive to realizing unified handling of the motion control of multiple axes during dynamic hovering from the control level. This is different from the related technologies that only achieve hovering by reducing the speed command of the frame rotation axis to zero. In this way, the controller can make multiple actuator axes enter a unified and coordinated locking control mode during hovering, thereby improving the multi-axis synchronization stability and overall control accuracy during dynamic hovering.

[0121] The controller can also integrate a high-performance processing unit and a real-time operating system. The high-performance processing unit receives angle or displacement information from each actuator axis collected by the position feedback unit, compares this information with preset motion trajectories and corresponding timestamps to calculate deviations, and then outputs control commands to the servo drives of each actuator axis through a control algorithm combining feedforward control and closed-loop feedback control. The controller uses a global high-precision clock source as a synchronization reference, and motion commands for each actuator axis are sent at high speed according to a unified timestamp, facilitating sub-millisecond multi-axis command synchronization. Simultaneously, the controller supports real-time online compensation for phase errors, speed errors, and mechanical hysteresis errors between multiple actuator axes. A hover-lock state machine module is located inside the controller and is used to switch between continuous rotation, hover-lock, and hover-release states. In continuous rotation, the controller uses the frame rotation axis as a virtual master axis to plan the motion trajectories of each slave axis. In hover-lock, each actuator axis switches to a locked control mode or a restricted fine-tuning control mode to attempt to maintain its spatial position stability. In the hover-release state, the controller smoothly guides each actuation axis to return to continuous rotation and re-establishes the synchronization reference relationship between the actuation axes to reduce potential synchronization abruptness or mechanical shock during motion recovery. The controller also works in conjunction with the safety monitoring module. When the safety monitoring module detects that the actuation axis position exceeds limits, speed is abnormal, or multi-axis synchronization error exceeds a preset threshold, the controller can automatically trigger protective measures such as limit control, emergency stop control, or safety degradation control. This helps ensure high-precision, multi-axis synchronized, and stable motion control during high-speed coordinated motion, dynamic hovering, and continuous rotation, providing support for precise dose delivery and spatial positioning in arc radiotherapy.

[0122] The safety monitoring module monitors the operating status of each actuator axis in real time and triggers limit control, emergency stop control, or safety degradation control when an abnormal state is detected. The safety monitoring module includes a high-precision sensing unit, a signal acquisition and processing unit, and a control interface unit. The high-precision sensing unit is electrically connected to each actuator axis and position feedback unit, and can acquire angle, displacement, speed, and torque signals of each actuator axis in real time, while simultaneously acquiring control commands and status information sent by the controller. The signal acquisition and processing unit compares and analyzes the acquired data in real time to determine whether each actuator axis exceeds a preset safety threshold. The preset safety thresholds may include position deviation thresholds, speed anomaly thresholds, synchronization error thresholds, and mechanical impact limits. When any actuator axis's status parameter exceeds the corresponding safety threshold, it is determined to be an abnormal state. The safety monitoring module sends protective action control commands to the controller and the corresponding servo drive through the control interface unit. These protective action control commands include limit control commands, emergency stop commands, and safety degradation control commands. These protective action control commands can immediately switch the frame rotation axis and each slave axis to a preset safety control mode or stop movement. The hovering lock state machine module can also automatically enter a safety lock state based on abnormal conditions. Thus, the safety monitoring module helps ensure the stability and accuracy of multi-axis coordinated motion during high-speed rotation, hovering lock, and hovering release. The safety monitoring module can employ redundant sensor configurations and real-time diagnostic algorithms, which helps improve system reliability. It can also record various abnormal events and status change data, providing data support for subsequent equipment maintenance and quality management, thereby contributing to the safe and reliable operation of the dynamic hovering arc radiotherapy equipment under high-precision, multi-axis synchronous motion conditions.

[0123] The multi-axis coordinated motion control device for dynamic hovering arc radiotherapy equipment provided in this application transforms dynamic hovering from a transient process into a controllable stable state by constructing a dual-state model of linked motion and coordinated locking states, and combining it with a hovering locking state machine for unified management. By introducing virtual master axis planning, feedforward and closed-loop control, inertial compensation, smooth state switching, and independent safety monitoring, it can work synergistically at multiple levels, helping to improve problems such as low synchronization accuracy, unstable switching, and susceptibility to vibration in multi-axis coordinated equipment during dynamic hovering. Especially in the high-precision application scenario of dynamic hovering arc radiotherapy, the multi-axis linked motion control device of this application helps to achieve microsecond-level high-precision linkage and coordination of "velocity-position-dose," which is beneficial to improving the accuracy and safety of radiotherapy.

[0124] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, which stores a computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located executes the above-described multi-axis cooperative motion control method for a dynamic hovering arc radiotherapy device.

[0125] According to another aspect of the embodiments of this application, an electronic device is also provided, including one or more processors and a memory, the memory being used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to perform the above-described multi-axis cooperative motion control method for a dynamic hovering arc radiotherapy device.

[0126] According to another aspect of the embodiments of this application, a computer program product is also provided, including a computer program or instructions, which, when executed by a processor, implement the above-described multi-axis coordinated motion control method for a dynamic hovering arc radiotherapy device.

[0127] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0128] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0129] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0130] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0131] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0132] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard drive, magnetic disk, or optical disk.

[0133] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A multi-axis coordinated motion control method for dynamic suspended arc radiotherapy apparatus, characterized in that, include: Collect the actual position information of multiple execution axes, which are execution axes related to the dynamic hovering arc radiotherapy device; Based on the preset target motion trajectory for the multiple execution axes and the actual position information, the target control state of the multiple execution axes at the current moment is determined, wherein the target control state includes at least a linkage motion state and a cooperative locking state; When the target control state is the linkage motion state, the multiple execution axes are controlled to perform coordinated motion according to the target motion trajectory; When the target control state is the cooperative locking state, at least one first execution axis among the plurality of execution axes is controlled to enter the position locking mode, and at least one second execution axis among the plurality of execution axes is controlled to enter the position maintaining mode, so as to perform multi-axis cooperative positioning operation at the target spatial position; wherein, the position maintaining mode represents that, under the premise of locking the basic position of the second execution axis, the spatial position of the second execution axis is controlled to remain stable or to be adjusted within a preset adjustment range, and the controlled adjustment is used to compensate for mechanical hysteresis or thermal deformation error; In the case of a dynamic hovering lock state, the position locking mode is used to use the rack rotation axis as the first actuation axis and maintain the angle of the rack rotation axis at the preset hovering angle through closed-loop control. The position maintenance mode includes a lock control mode or a restricted fine-tuning control mode. The lock control mode is used to control the second actuation axis to maintain itself at the measured position when the second actuation axis enters the measured position in the dynamic hovering lock state. The restricted fine-tuning control mode is used to constrain the second actuation axis to make dynamic adjustments within a preset adjustment range based on the current locked position to compensate for mechanical hysteresis or thermal deformation errors. The second actuation axis is a rotation axis other than the rack rotation axis.

2. The method of claim 1, wherein, The plurality of execution axes include at least a gantry rotation axis and N other rotation axes, wherein the N other rotation axes include at least one of the following: a treatment head rotation axis, a collimator rotation axis, a multi-leaf grating axis, and a patient support bed axis, and N is an integer greater than or equal to 1.

3. The method of claim 2, wherein, The linked motion state is a continuous rotating arc motion state, and the target motion trajectory is a dynamic hovering arc radiotherapy trajectory based on the gantry rotation angle; the cooperative locking state is a dynamic hovering locking state, and the target spatial position is a spatial position determined based on a preset hovering angle.

4. The method according to claim 1, characterized in that, When the target control state is the linked motion state, controlling the multiple execution axes to perform coordinated motion according to the target motion trajectory includes: When the target control state is the linkage motion state, according to the target motion trajectory and combined with the global clock source, a target state corresponding to each execution axis in the discrete time series is generated, wherein the target state includes at least the position and velocity of each execution axis at any time in the discrete time series; Based on the target state corresponding to each execution axis and the dynamic model corresponding to each execution axis, the feedforward control quantity required to drive each execution axis to achieve the target state is determined, wherein the dynamic model is used at least to compensate for the nonlinear friction force of the frame, adjust the speed of the execution axis, and adjust the real-time radiation dose; The feedforward control quantity controls the multiple execution axes to move in coordination according to the target motion trajectory.

5. The method according to claim 4, characterized in that, Controlling the plurality of actuator axes to perform coordinated motion according to the target motion trajectory based on the feedforward control quantity includes: Within each control cycle, the actual state of each execution axis is synchronously acquired; the actual state of each execution axis is compared with the target state at the corresponding time point, the independent tracking error of each execution axis is determined based on the comparison result, and the inter-axis synchronization error is determined based on the motion coupling relationship between multiple axes; Based on the independent tracking error and the inter-axis synchronization error, a closed-loop feedback correction amount is generated to simultaneously correct the error of each execution axis and maintain the inter-axis cooperative relationship. The feedforward control quantity and the closed-loop feedback correction quantity are combined to obtain the cooperative drive command for each execution axis; Based on the discrete time sequence, the collaborative drive command is synchronously sent to the driver of each execution axis via a communication bus to control the multiple execution axes to perform coordinated motion according to the target motion trajectory.

6. The method according to claim 4, characterized in that, Based on the preset target motion trajectories for the multiple execution axes, and in conjunction with a global clock source, a target state corresponding to each execution axis in a discrete time series is generated, including: In the case where the plurality of execution axes include at least a rack rotation axis and N other rotation axes besides the rack rotation axis, the rack rotation axis is designated as the master axis and the N other rotation axes are designated as slave axes; Based on the global clock source, at least one target position corresponding to each slave axis on the target motion trajectory of the master axis is determined, wherein each target position corresponds to a point in time in the discrete time series; The target object corresponding to each execution axis on the discrete time series is determined based on the at least one target location.

7. The method according to claim 1, characterized in that, The method further includes: When the rack rotation axis enters the position locking mode, inertia compensation calculation is performed based on the real-time load inertia and speed change rate of the rack rotation axis, and a target torque command is generated according to the result of the inertia compensation calculation. The target torque command is used to suppress low-speed vibration and positioning drift of the rack rotation axis, and the low-speed vibration is used to characterize the vibration caused by the rack rotation axis when it runs at a speed lower than a preset speed.

8. The method according to claim 1, characterized in that, Based on the preset target motion trajectories for the multiple execution axes and the actual position information, the target control state of the multiple execution axes at the current moment is determined, including: Compare at least one main execution axis position in the actual position information with a preset state switching point in the target motion trajectory; When the position of the main execution axis reaches the preset state switching point, the trigger control state switches from the linkage motion state to the cooperative locking state, or switches from the cooperative locking state to the linkage motion state.

9. The method according to claim 1, characterized in that, The process of switching the multiple execution axes from the cooperative locking state to the linked motion state includes: a lock release state, wherein, in the lock release state, the controller smoothly reconstructs the synchronization reference relationship between each execution axis, and controls the acceleration of each execution axis based on the synchronization reference relationship to restore cooperative motion.

10. The method according to claim 1, characterized in that, The method further includes: Real-time monitoring of multiple deviation indicators for each of the multiple execution axes during operation, wherein the multiple deviation indicators include at least position deviation, speed deviation, and synchronization error; If any deviation indicator is detected to exceed a preset safety threshold, a safety control command is triggered, wherein the safety control command is used to implement limit control, emergency stop or safety degradation control for the actuator axis.

11. A multi-axis coordinated motion control device for a dynamic hovering arc radiotherapy device, used to implement the multi-axis coordinated motion control method for a dynamic hovering arc radiotherapy device as described in any one of claims 1 to 10, characterized in that, include: Multiple execution axes associated with dynamic hovering arc radiotherapy equipment; A controller is communicatively connected to the plurality of execution axes; wherein the controller is used to collect the actual position information of the plurality of execution axes, and determine the target control state of the plurality of execution axes at the current moment based on the preset target motion trajectory for the plurality of execution axes and the actual position information, wherein the target control state includes at least a linkage motion state and a cooperative locking state; The controller is further configured to control the plurality of execution axes to perform coordinated motion according to the target motion trajectory when the target control state is the linkage motion state; and to control at least one first execution axis among the plurality of execution axes to enter a position locking mode and control at least one second execution axis among the plurality of execution axes to enter a position maintaining mode, so as to perform multi-axis coordinated positioning operation at the target spatial position; wherein, the position maintaining mode represents, under the premise of locking the basic position of the second execution axis, controlling the spatial position of the second execution axis to remain stable or to perform controlled adjustment within a preset adjustment range, the controlled adjustment being used to compensate for mechanical hysteresis or thermal deformation error.

12. The apparatus according to claim 11, characterized in that, The controller integrates a hovering and locking state machine module, which is used to manage the switching of control states, including the linkage motion state, the cooperative locking state, and the lock release state.

13. The apparatus according to claim 11, characterized in that, The plurality of execution axes include at least a gantry rotation axis and N other rotation axes, wherein the N other rotation axes include at least one of the following: a treatment head rotation axis, a collimator rotation axis, a multi-leaf grating axis, and a patient support bed axis, and N is an integer greater than or equal to 1.

14. The apparatus according to claim 13, characterized in that, The first actuating axis is the rack rotation axis, and the second actuating axis is an actuating axis other than the rack rotation axis among the plurality of actuating axes.

15. The apparatus according to claim 11, characterized in that, The device also includes a position feedback unit, which is disposed on each execution axis and communicates with the controller to provide the actual position information of each execution axis.

16. The apparatus according to claim 15, characterized in that, The controller is connected to the servo drivers on each of the execution axes and the position feedback unit via a communication bus.

17. The apparatus according to claim 11, characterized in that, The device also includes a safety monitoring module for monitoring the operating status of the plurality of execution axes and triggering a protection action when any execution axis is detected to be operating abnormally. The protection action is at least used to stop the movement of all execution axes when any execution axis is operating abnormally.

18. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, wherein when the computer program is executed, the device containing the computer-readable storage medium performs the multi-axis coordinated motion control method for a dynamic hovering arc radiotherapy device as described in any one of claims 1 to 10.

19. An electronic device, characterized in that, It includes one or more processors and a memory, the memory being used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to perform the multi-axis coordinated motion control method for a dynamic hovering arc radiotherapy device as described in any one of claims 1 to 10.

20. A computer program product, characterized in that, It includes a computer program or instructions that, when executed by a processor, implement the multi-axis coordinated motion control method for a dynamic hovering arc radiotherapy device as described in any one of claims 1 to 10.

Images