CN-121979297-A - Double-shaft control method and system of cone beam computer tomography equipment

CN121979297ACN 121979297 ACN121979297 ACN 121979297ACN-121979297-A

Abstract

The invention discloses a double-shaft control method and a double-shaft control system of cone beam computer tomography equipment, which relate to the technical field of equipment control and comprise the following steps of obtaining guide rail contact state data of rotating arms at different heights and angles, constructing guide rail load distribution topology, identifying the offset state of a load acting line based on the guide rail load distribution topology, performing time sequence expansion on the guide rail load distribution topology based on the offset state to obtain a guide rail stress unbalance set, performing coupling reconstruction on a target motion path of the rotating shafts and lifting shafts based on the guide rail stress unbalance set to obtain double-shaft cooperative motion tracks, performing coordinated adjustment on the motion speed change process of the rotating shafts and the lifting shafts to obtain a load balance state, generating double-shaft drive control instructions based on the load balance state, and controlling the rotating arms to complete a gesture adjustment process, so that the problem of guide rail contact interface stress unbalance caused by dynamic change of the load distribution of the rotating arms in the double-shaft cooperative motion process is solved.

Inventors

WANG YI
ZHENG HUI
JIN XIN
ZHAO DANXIA
WANG SULING
LIANG LIN
WANG CHAO
LIAO XUHUI

Assignees

台州市计量技术研究院

Dates

Publication Date: 20260505
Application Date: 20260407

Claims (10)

1. A method for biaxial control of a cone beam computed tomography apparatus, comprising the steps of: acquiring guide rail contact state data of the rotating arm at different heights and angles, and constructing a guide rail load distribution topology according to the guide rail contact state data; Identifying the offset state of a load acting line based on the guide rail load distribution topology, and performing time sequence expansion on the guide rail load distribution topology based on the offset state to obtain a guide rail stress unbalance set; coupling reconstruction is carried out on the target motion paths of the rotating shaft and the lifting shaft based on the guide rail stress unbalance set, so that a double-shaft cooperative motion track is obtained; in the execution process of the double-shaft cooperative motion trail, the motion speed change process of the rotating shaft and the lifting shaft is coordinated and regulated to obtain a load balance state; and generating a biaxial drive control instruction based on the load balance state, and controlling the rotating arm to complete the posture adjustment process.
2. The method for biaxial control of a cone beam computed tomography apparatus according to claim 1, wherein the acquiring the rail contact state data of the rotating arm at different heights and angles and constructing the rail load distribution topology according to the rail contact state data comprises: acquiring contact pressure distribution data between a guide rail sliding block and a guide rail contact surface when the rotating arm moves along a scanning track at a plurality of preset height positions respectively, and real-time inclination angle data of the rotating arm at the corresponding positions to obtain guide rail contact state data; Performing time axis alignment on the guide rail contact state data, and performing association mapping on contact pressure distribution data and real-time inclination angle data under the same time stamp to obtain a contact state time sequence set; Extracting the spatial distribution form of the contact pressure distribution data corresponding to each height position in the contact state time sequence set, and sequencing the spatial distribution form according to the change sequence of the inclination angle of the rotating arm to obtain a contact pressure sequence; carrying out difference calculation on contact pressure distribution forms under adjacent dip angles in a contact pressure sequence, and identifying a contact pressure mutation position according to a difference calculation result; Extracting interface pressure characteristic vectors of contact pressure distribution forms at contact pressure abrupt change positions, and fusing the interface pressure characteristic vectors with corresponding height positions and real-time inclination angle data to obtain load distribution discrete point clouds; and performing space surface fitting on the load distribution discrete point cloud to obtain a guide rail load distribution topology.
3. The dual-axis control method of a cone beam computed tomography apparatus according to claim 2, wherein the identifying the offset state of the load acting line based on the rail load distribution topology, and performing time sequence expansion on the rail load distribution topology based on the offset state, obtains a rail stress unbalance set, specifically: Extracting contact pressure distribution of each spatial position in the guide rail load distribution topology, and extracting the spatial gravity center of the guide rail load distribution based on the contact pressure distribution; taking the space gravity center as a load center point, and calculating a relative displacement vector of the load center point and a guide rail geometric center point in a space coordinate system to obtain an initial offset vector of a load acting line; Continuously sampling the initial offset vector according to a preset time interval to obtain an offset vector time sequence; Carrying out phase space reconstruction on the offset vector time sequence, and extracting the offset direction change rate and the offset distance accumulation amount at each moment to obtain an offset state of a load acting line; And (3) carrying out time sequence superposition on the offset state and the guide rail load distribution topology to obtain the guide rail stress unbalance distribution under each time section, and obtaining a guide rail stress unbalance set.
4. The method for biaxial control of a cone beam computed tomography apparatus according to claim 3, wherein the coupling reconstruction is performed on the target motion path of the rotation axis and the lifting axis based on the stress unbalance set of the guide rail, so as to obtain a biaxial coordinated motion path, specifically: taking the stress unbalance set of the guide rail as a constraint boundary, and extracting an equipotential line cluster of stress unbalance distribution of the guide rail under each time section; Calculating the curvature change rate of each equipotential line in the equipotential line cluster, and identifying a stress abrupt change area of the contact surface of the guide rail according to the curvature change rate; Mapping the stress abrupt change region to a movement space of the rotating shaft and the lifting shaft to obtain a first movement constraint boundary of the rotating shaft and the lifting shaft; And in the first motion constraint boundary, taking the initial motion paths of the rotating shaft and the lifting shaft as base lines, and adopting a path planning algorithm to synchronously adjust the motion trajectories of the rotating shaft and the lifting shaft to obtain a biaxial collaborative motion trajectory.
5. The method for biaxial control of a cone beam computed tomography apparatus according to claim 4, wherein the mapping the stress abrupt change region to the movement space of the rotation axis and the lifting axis results in a first movement constraint boundary of the rotation axis and the lifting axis, specifically: Extracting a space coordinate set of the stress abrupt change region on the contact surface of the guide rail, and converting the space coordinate set into a rotation axis coordinate system and a lifting axis coordinate system to obtain a rotation axis constraint point set and a lifting axis constraint point set; Respectively calculating the angle interval between adjacent constraint points in the rotation shaft constraint point set and the height interval between adjacent constraint points in the lifting shaft constraint point set to obtain a rotation shaft forbidden interval set and a lifting shaft forbidden interval set; carrying out Cartesian product operation on the rotation shaft forbidden interval set and the lifting shaft forbidden interval set to obtain a first forbidden region; and marking the first forbidden region in the movement space of the rotating shaft and the lifting shaft to obtain a first movement constraint boundary of the rotating shaft and the lifting shaft.
6. The method for controlling a cone beam computed tomography apparatus according to claim 5, wherein in the process of executing the dual-axis cooperative motion trajectory, the motion speed change process of the rotating shaft and the lifting shaft is coordinated and adjusted to obtain a load balance state, specifically: discretizing a biaxial collaborative motion track into a plurality of track points according to time, and configuring a preset rotating shaft speed parameter and a preset lifting shaft speed parameter for each track point; In the execution process of the double-shaft cooperative motion track, real-time load distribution data of the rotating arm are collected in real time, and the real-time load distribution data and the stress unbalance distribution of the corresponding time section in the stress unbalance concentration of the guide rail are subjected to differential ratio pair to obtain real-time load deviation distribution; Calculating the speed compensation quantity of the rotating shaft and the lifting shaft according to the real-time load deviation distribution, and superposing the speed compensation quantity on a preset rotating shaft speed parameter and lifting shaft speed parameter to obtain a rotating shaft real-time speed instruction and a lifting shaft real-time speed instruction; And controlling the rotation shaft and the lifting shaft to move according to the real-time speed command of the rotation shaft and the real-time speed command of the lifting shaft until the real-time load deviation distribution converges to a preset deviation range, and obtaining a load balance state.
7. The method for biaxial control of a cone beam computed tomography apparatus according to claim 6, wherein the calculating the speed compensation amounts of the rotation axis and the lifting axis according to the real-time load deviation distribution is specifically as follows: dividing real-time load deviation distribution into a plurality of load deviation intervals along the extending direction of the rotating arm, and calculating a load deviation integral value in each load deviation interval; determining an asymmetric direction of the load deviation according to the positive sign and the negative sign of the load deviation integral value, wherein the asymmetric direction points to a load deviation interval with a larger absolute value of the load deviation integral value; taking the opposite direction of the asymmetric direction as a compensation direction, and determining a compensation amplitude value based on the absolute value of the load deviation integral value; the compensation amplitude is proportionally distributed to the rotation shaft speed compensation amount and the lifting shaft speed compensation amount.
8. The method for biaxial control of a cone beam computed tomography apparatus according to claim 7, wherein the distributing the compensation amplitude to the rotation axis speed compensation amount and the elevation axis speed compensation amount according to a preset ratio is specifically: Extracting an asymmetric component in the real-time load deviation distribution, and calculating the projection length of the asymmetric component in the rotation axis direction and the lifting axis direction; Determining the distribution ratio of the speed compensation quantity of the rotating shaft to the speed compensation quantity of the lifting shaft according to the ratio of the projection length; And respectively distributing the compensation amplitude to the rotation shaft speed compensation quantity and the lifting shaft speed compensation quantity according to the distribution proportion.
9. The method for biaxial control of a cone beam computed tomography apparatus according to claim 8, wherein the generating a biaxial driving control command based on the load balance state and controlling the rotating arm to complete the posture adjustment process comprises: Taking the real-time speed command of the rotating shaft and the real-time speed command of the lifting shaft in the load balance state as reference parameters of a biaxial drive control command; Inputting reference parameters of the double-shaft driving control instruction into a rotating shaft driver and a lifting shaft driver, and respectively controlling the rotating shaft to perform rotating motion according to the real-time speed instruction of the rotating shaft and controlling the lifting shaft to perform lifting motion according to the real-time speed instruction of the lifting shaft; in the moving process of the rotating shaft and the lifting shaft, the change of the attitude angle of the rotating arm is monitored in real time, and a real-time speed instruction of the rotating shaft and a real-time speed instruction of the lifting shaft are fed back and adjusted according to the change of the attitude angle; And when the rotating arm reaches the target attitude angle and the real-time load deviation distribution is continuously kept within the preset deviation range, the attitude adjustment process is completed.
10. A dual-axis control system of a cone-beam computed tomography apparatus, applied to the dual-axis control method of a cone-beam computed tomography apparatus according to any one of claims 1 to 9, comprising a topology construction module, a timing expansion module, a trajectory generation module, a speed adjustment module, and a dual-axis control module: The topology construction module is used for acquiring guide rail contact state data of the rotating arm at different heights and angles and constructing guide rail load distribution topology according to the guide rail contact state data; the time sequence expansion module is used for identifying the offset state of the load acting line based on the guide rail load distribution topology and carrying out time sequence expansion on the guide rail load distribution topology based on the offset state to obtain a guide rail stress unbalance set; the track generation module is used for carrying out coupling reconstruction on the target motion paths of the rotating shaft and the lifting shaft based on the guide rail stress unbalance set to obtain a double-shaft cooperative motion track; the speed adjusting module is used for carrying out coordination adjustment on the motion speed change process of the rotating shaft and the lifting shaft in the execution process of the double-shaft cooperative motion trail so as to obtain a load balance state; and the double-shaft control module is used for generating a double-shaft driving control instruction based on the load balance state and controlling the rotating arm to complete the posture adjustment process.

Description

Double-shaft control method and system of cone beam computer tomography equipment Technical Field The invention relates to the technical field of equipment control, in particular to a double-shaft control method and a double-shaft control system of cone beam computer tomography equipment. Background Cone beam computer tomography equipment is imaging equipment which performs multi-angle scanning on a detected object through cone beam and reconstructs three-dimensional structure information, and is widely applied to the fields of medical imaging, industrial nondestructive detection and the like. In such devices, a rotating arm structure for carrying the radiation source and the detector is generally provided, surrounding scanning is realized through the rotating shaft, and meanwhile, layer acquisition at different height positions is realized by matching with the lifting shaft, so that multidimensional data acquisition in a space range is completed. Therefore, the double-shaft linkage mechanism formed by the rotating shaft and the lifting shaft becomes a key execution unit for ensuring the scanning precision and the imaging quality. However, during the biaxial co-motion of a cone beam computed tomography apparatus, the rotating arm carries the radiation source and detector, the mass distribution of which is not completely uniform in space. When the rotating arm moves under the combination of different heights and rotation angles, the load born by the guide rail contact interface can present dynamic distribution characteristics along with the change of the gesture. This dynamic distribution causes a time-varying shift in the load line with respect to the geometric center of the rail such that the rail is no longer uniformly stressed and localized areas may be overloaded or concentrated. Along with the continuous change of the rotation angle and the lifting height, unbalanced load effects can be accumulated, and a slight tilting trend can be formed on the part of the guide rail, so that the stability and the accuracy of the whole movement of the rotating arm are affected. In addition, because dynamic changes in force distribution are difficult to compensate by a single preset trajectory or fixed speed control, such load shifting not only increases the risk of wear of the guide rail, but may also negatively impact the attitude control and imaging accuracy of the swivel arm during scanning. The present invention proposes a solution to the above-mentioned problems. Disclosure of Invention In order to overcome the defects in the prior art, the embodiment of the invention provides a double-shaft control method and a double-shaft control system of cone beam computer tomography equipment, which are used for constructing a rotating arm guide rail load distribution topology, identifying a load acting line deviation state, realizing coupling reconstruction and real-time speed adjustment of a double-shaft cooperative motion path and solving the problem of unbalanced stress of a guide rail contact interface due to dynamic change of the load distribution of the rotating arm in the double-shaft cooperative motion process. In order to achieve the above purpose, the present invention provides the following technical solutions: A double-shaft control method for cone beam computer tomography equipment includes the following steps of obtaining guide rail contact state data of a rotating arm at different heights and angles, constructing guide rail load distribution topology according to the guide rail contact state data, identifying offset states of load acting lines based on the guide rail load distribution topology, performing time sequence expansion on the guide rail load distribution topology based on the offset states to obtain guide rail stress unbalance sets, performing coupling reconstruction on target motion paths of the rotating shaft and a lifting shaft based on the guide rail stress unbalance sets to obtain double-shaft collaborative motion tracks, performing coordinated adjustment on motion speed change processes of the rotating shaft and the lifting shaft in the double-shaft collaborative motion track execution process to obtain load balance states, generating double-shaft drive control instructions based on the load balance states, and controlling the rotating arm to complete posture adjustment process. In a preferred embodiment, the method acquires the guide rail contact state data of the rotating arm at different heights and angles, and constructs the guide rail load distribution topology according to the guide rail contact state data, specifically: the method comprises the steps of collecting contact pressure distribution data between a guide rail sliding block and a guide rail contact surface when a rotating arm moves along a scanning track at a plurality of preset height positions respectively, and real-time inclination angle data of the rotating arm at the corresponding position to obtain guide rail contact st