Robust impedance filter based autonomous scanning control method and system for an ultrasound robot

Abstract

The application discloses a kind of based on robust impedance filtering ultrasonic robot autonomous scanning control method and system, belong to medical robot control technical field.The application is by constructing second-order impedance dynamics model, the physical contact between ultrasonic probe and human tissue is abstracted as the dynamic coupling system including mass, damping, spring characteristics;Robust integral saturation error control theory is introduced to design impedance filter, combined with image-based visual servoing, realize the high decoupling closed-loop control of force sense and visual information;Multi-level impedance adjustment strategy is used, seamless mode switching is realized between free motion stage and contact scanning stage.The application realizes high-precision autonomous scanning full autonomy, high robustness force sense tracking control in dynamic environment, effectively improves clinical automatic scanning standardization degree and operation safety.

Description

Technical Field

[0001] This invention relates to the field of medical robot control technology, and more specifically, to an autonomous scanning control method and system for an ultrasound robot based on robust impedance filtering. Background Technology

[0002] Ultrasound examination, as a non-invasive, real-time clinical diagnostic tool, is widely used in areas such as abdominal, cardiovascular, and ablation surgery guidance. However, traditional manual ultrasound scanning suffers from problems such as high labor intensity, poor repeatability, and reliance on physician experience. In recent years, medical robot-assisted ultrasound scanning has become a research hotspot. Replacing or assisting physicians in performing ultrasound scanning operations with robotic technology has become an important development direction for improving the standardization of ultrasound examinations.

[0003] Maintaining a stable and appropriate contact force between the ultrasound probe and the human body surface during autonomous scanning is crucial for ensuring image quality. Insufficient contact force leads to poor acoustic coupling and image artifacts; excessive contact force may cause patient discomfort or even tissue damage. Existing technologies suffer from the following main drawbacks:

[0004] First, the limitations of constant force control. Most existing ultrasound robots employ a constant pressure control strategy. However, in actual clinical scenarios, due to the patient's breathing fluctuations, muscle contractions, and dynamic changes in tissue properties during ablation surgery, constant force is difficult to simulate the feel of an advanced physician dynamically adjusting pressure based on tissue feedback, and cannot meet the needs of complex clinical tasks.

[0005] Second, there is an over-reliance on prior environmental information. Traditional impedance control often requires the precise surface pose of the subject to be reconstructed in advance using CT / MRI or high-precision point clouds. Once the subject undergoes a slight displacement, the robot coordinate system and the environmental coordinate system become mismatched, leading to drastic fluctuations in contact force and poor system robustness.

[0006] Third, the tracking accuracy of time-varying contact force is low. During ablation procedures or certain imaging examinations, the probe pressure needs to change in a specific pattern over time (such as wave-like pressing). Traditional PID controllers or simple impedance control exhibit significant hysteresis and steady-state errors when handling nonlinear time-varying contact forces, making it difficult to reproduce the dynamic pressing techniques of expert physicians.

[0007] The above shortcomings need to be improved. Summary of the Invention

[0008] To overcome the limitations of constant force control, strong dependence on prior environmental information, and low accuracy of time-varying contact force tracking in existing technologies for autonomous scanning of ultrasound robots, this invention provides an autonomous scanning control method and system for ultrasound robots based on robust impedance filtering. By using robust integral saturation error control theory to solve the robustness problem of time-varying contact force tracking, it achieves high-precision autonomous scanning fully autonomous and highly robust force tracking control in dynamic environments (such as in ablation surgery), effectively improving the standardization and operational safety of clinical automated scanning.

[0009] The technical solution of this invention is as follows:

[0010] In a first aspect, the present invention provides an autonomous scanning control method for an ultrasonic robot based on robust impedance filtering, comprising the following steps:

[0011] An ultrasonic robot hardware system is constructed, comprising a robot, an ultrasonic probe mounted at the end of the robot's robotic arm, and a six-dimensional force / torque sensor coupled between the ultrasonic probe and the flange of the robotic arm.

[0012] Establish the calibration relationship between the robot end effector coordinate system, the force sensor coordinate system, and the ultrasonic image coordinate system;

[0013] A second-order impedance dynamics model is constructed, which abstracts the physical contact behavior between the ultrasound probe and human tissue into a dynamic coupling system that includes mass, damping, and spring characteristics. By adjusting the virtual dynamic parameters, the compliance of the ultrasound probe in the direction of force is set.

[0014] Design a robust impedance filter based on robust integral saturation error control theory;

[0015] Based on the real-time feedback from the six-dimensional force / torque sensor, the system switches between two operating modes: free motion mode and contact scanning mode. In free motion mode, the ultrasound probe is guided to reach the target initial point along a preset path. In contact scanning mode, the normal displacement compensation amount output by the robust impedance filter is spatially decoupled from the tangential scanning speed command. By updating the image Jacobian matrix in real time, the force perception deviation is converted into the desired joint speed command at the end of the robotic arm, driving the ultrasound probe to achieve smooth sliding scanning along the anatomical contour of human tissue.

[0016] During the scanning process, the robust impedance filter is driven to generate a corresponding dynamic response by injecting a time-varying waveform into the reference force signal.

[0017] As a preferred embodiment of the present invention, the robust impedance filter introduces a continuous integral term with saturation constraints to compensate for the uncertainty of environmental stiffness and nonlinear disturbances.

[0018] As a preferred embodiment of the present invention, the robust impedance filter is constrained based on the Lyapunov stability criterion.

[0019] As a preferred embodiment of the present invention, the adaptive gain term in the robust impedance filter is used to adjust the tracking speed and overshoot suppression capability of the time-varying contact force.

[0020] As a preferred embodiment of the present invention, the robust impedance filter incorporates physical interactive safety redundancy logic and performs weighted smoothing on the robotic arm's motion sequence through an exponential decay function.

[0021] As a preferred embodiment of the present invention, the step of switching the system's operating mode based on the real-time feedback from the six-dimensional force / torque sensor includes:

[0022] When the ultrasound probe is in the free movement stage without contacting human tissue, the system's working mode is switched to the free movement mode; when the six-dimensional force / torque sensor detects that the contact force between the ultrasound probe and human tissue reaches a preset threshold, the system's working mode is switched to the contact scanning mode.

[0023] As a preferred embodiment of the present invention, in the contact scanning mode, the visual feedback of the ultrasound image based on the image visual servo processing spatially decouples the normal displacement compensation amount output by the robust impedance filter from the tangential scanning speed command.

[0024] As a preferred embodiment of the present invention, the expression of the second-order impedance dynamics model is as follows: ;

[0025] Where Md is virtual mass, Bd is virtual damping, Kd is virtual stiffness, x is the actual position of the probe, x˙ is the actual velocity of the probe, x¨ is the actual acceleration of the probe, xd is the desired position of the probe, x˙d is the desired velocity of the probe, x¨d is the desired acceleration of the probe, Fe is the actual contact force, and Fd is the desired contact force.

[0026] As a preferred embodiment of the present invention, the time-varying waveform is a sine wave or a smooth trapezoidal wave.

[0027] Secondly, the present invention provides an ultrasonic robot autonomous scanning control system based on robust impedance filtering, and an ultrasonic robot autonomous scanning control method based on robust impedance filtering for executing any of the above-mentioned schemes, comprising:

[0028] The hardware execution module includes a six-degree-of-freedom industrial robot, an ultrasonic probe installed at the end of the robotic arm of the six-degree-of-freedom industrial robot, and a six-dimensional force / torque sensor coupled between the ultrasonic probe and the flange of the robotic arm.

[0029] The calibration module is used to establish the calibration relationship between the robot end effector coordinate system, the force sensor coordinate system, and the ultrasonic image coordinate system.

[0030] Impedance modeling module is used to construct a second-order impedance dynamic model, which abstracts the physical contact behavior between the ultrasound probe and human tissue into a dynamic coupling system that includes mass, damping, and spring characteristics. By adjusting the virtual dynamic parameters, the compliance of the ultrasound probe in the direction of force is set.

[0031] The robust impedance filtering module is used to filter the contact force deviation based on the robust integral saturation error control theory and output the normal expected displacement compensation amount.

[0032] An impedance adjustment module is used to switch the system's operating mode based on real-time feedback from the six-dimensional force / torque sensor.

[0033] The visual servo module uses an image visual servo algorithm to process the visual feedback of the ultrasound image and spatially decouples the normal displacement compensation amount output by the robust impedance filter from the tangential scanning speed command.

[0034] The time-varying force tracking module is used to inject a time-varying waveform into the reference force signal to drive the robust impedance filter to generate a corresponding dynamic response.

[0035] According to the above-described solution, the beneficial effects of this invention are as follows:

[0036] 1. By constructing a second-order impedance dynamics model, virtual mass, virtual damping, and virtual stiffness parameters can be flexibly adjusted to accurately simulate the variable pressing sensation of experienced physicians scanning different anatomical sites; at the same time, relying on the injection of time-varying waveforms with reference force signals, regular time-varying contact forces such as sine waves and trapezoidal waves can be accurately tracked, effectively adapting to dynamic changes in tissue characteristics such as human breathing fluctuations, muscle contractions, and tissue hardening due to heat during ablation surgery, meeting the force control needs of complex clinical tasks such as ablation surgery guidance and angiography-specific examinations;

[0037] 2. No need to accurately reconstruct prior information of the environmental surface in advance. Even if the subject has slight displacement of body position or local tissue morphology changes, the posture deviation can be corrected in real time through the six-dimensional force / torque sensor and image vision servoing. This avoids the violent fluctuation of contact force caused by the mismatch between the robot and the environmental coordinate system, and greatly improves the robustness and fault tolerance of the system in the unstructured clinical environment.

[0038] 3. By introducing a continuous integral term with saturation constraints to construct a robust impedance filter, combined with Lyapunov stability constraints, the shortcomings of traditional PID and simple impedance control in handling nonlinear time-varying forces, such as significant time lag and large steady-state error, are overcome. Force fluctuations can be controlled with millinewton precision, while avoiding the integral saturation (windup) problem of traditional integral control. With adaptive gain design, the tracking response speed and overshoot suppression capability of time-varying forces are significantly improved, accurately reproducing the dynamic pressure techniques of expert physicians.

[0039] 4. By spatially decoupling the normal displacement compensation amount and tangential scanning speed command output by the robust impedance filter through image-based visual servoing, it can adaptively and autonomously slide and scan to conform to the anatomical contour of human tissue, effectively avoiding motion stagnation and position drift caused by excessive local impedance, ensuring the continuity and conformity of the scanning path, and improving the continuity of ultrasound imaging and the stability of clinical scanning. Attached Figure Description

[0040] Figure 1 This is a flowchart illustrating an embodiment of the ultrasonic robot autonomous scanning control method based on robust impedance filtering according to the present invention.

[0041] Figure 2 This is a schematic diagram of the structure of an ultrasonic robot autonomous scanning control system based on robust impedance filtering in one embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0043] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0044] It should be noted that the terms "comprising" and "having," and any variations thereof, in the specification and claims of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus.

[0045] like Figure 1 As shown, one embodiment of the present invention provides an autonomous scanning control method for an ultrasonic robot based on robust impedance filtering, comprising the following steps:

[0046] Step S1, Hardware Construction: Construct the ultrasonic robot hardware system, which includes a six-degree-of-freedom industrial robot, an ultrasonic probe installed at the end of the six-degree-of-freedom industrial robot arm, a six-dimensional force / torque sensor coupled between the ultrasonic probe and the flange of the robotic arm, and supporting control modules, ultrasonic imaging modules, and data acquisition modules; among them, the six-dimensional force / torque sensor is used to monitor the contact force at the end of the ultrasonic probe in real time, with a sampling frequency of not less than 1000Hz to ensure high-frequency response capability to dynamic contact forces.

[0047] Step S2, Coordinate System Calibration: Establish the calibration relationship between the robot end effector coordinate system, the force sensor coordinate system, and the ultrasonic image coordinate system to provide a geometric basis for subsequent multi-source information fusion and spatial decoupling control. The specific calibration process is as follows:

[0048] First, the hand-eye calibration method is used to calibrate the robot end-effector coordinate system and the force sensor coordinate system: the calibration target is fixed to the end of the force sensor, and the robot drives the target to move in multiple postures in the workspace. The laser tracker collects the coordinate data of the target in the robot end-effector coordinate system and the force sensor coordinate system. The rotation matrix and translation vector between the two coordinate systems are solved by the least squares method to achieve accurate alignment of the coordinate systems. The calibration error is controlled within ±0.03mm.

[0049] Secondly, the image calibration method is used to calibrate the ultrasonic image coordinate system and the force sensor coordinate system: the standard calibration phantom is placed within the scanning range of the ultrasonic probe, the probe posture is adjusted to make the feature points of the calibration phantom clearly imaged, the image coordinates of the feature points are obtained through the ultrasonic imaging module, and the spatial coordinates corresponding to the feature points are obtained through the force sensor and the robot. The mapping relationship between the image coordinates and the spatial coordinates is established, and the transformation parameters between the ultrasonic image coordinate system and the force sensor coordinate system are solved.

[0050] Finally, by integrating the results of the three calibrations, a unified calibration model was established for the robot end effector coordinate system, the force sensor coordinate system, and the ultrasonic image coordinate system. The coordinate data of the three coordinate systems were uniformly transformed into the robot base coordinate system to ensure the spatial consistency of force feedback, visual feedback, and robot motion control, providing a reliable guarantee for subsequent spatial decoupling and multi-source information fusion.

[0051] Step S3, Second-order Impedance Dynamics Modeling: Construct a second-order impedance dynamics model, abstracting the physical contact behavior between the ultrasound probe and human tissue into a dynamic coupling system incorporating mass, damping, and spring characteristics. This second-order impedance dynamics model allows the system to artificially set the compliance of the ultrasound probe in the direction of force by adjusting dynamic parameters such as virtual mass, virtual damping, and virtual stiffness, thereby simulating the flexible pressing sensation of clinicians when scanning different anatomical sites.

[0052] The expression for the second-order impedance dynamics model is: ;

[0053] Where Md is virtual mass, Bd is virtual damping, Kd is virtual stiffness, x is the actual position of the probe, x˙ is the actual velocity of the probe, x¨ is the actual acceleration of the probe, xd is the desired position of the probe, x˙d is the desired velocity of the probe, x¨d is the desired acceleration of the probe, Fe is the actual contact force, and Fd is the desired contact force.

[0054] Step S4: Robust Impedance Filter Design: Design a robust impedance filter based on the Robust Integral of SATuration Error (RISATE) control theory to address issues such as environmental stiffness uncertainty, nonlinear disturbances, and integral saturation, ensuring the system's control stability and accuracy in complex clinical scenarios. The specific design is as follows:

[0055] The robust impedance filter consists of three parts: a robust control term, a continuous integral term with saturation constraints, and safety redundancy logic. These parts work together to achieve disturbance compensation, error suppression, and safety protection.

[0056] Continuous integral term with saturation constraint: A saturation function is introduced to constrain the integral term. The saturation threshold is set according to the maximum allowable displacement of the probe (0.5-2mm), which effectively avoids the integral saturation (windup) phenomenon common in traditional integral control and prevents control instability caused by integral accumulation. At the same time, this integral term can accumulate contact force error in real time, realize accurate compensation for environmental stiffness uncertainty and nonlinear disturbances (such as tissue elastic change and external micro-collisions), and improve the robustness of the filter.

[0057] Robust control term: An adaptive robust control algorithm is adopted, and an adaptive gain term (with a value range of 0.1-1.0) is introduced. It can adjust the gain parameter in real time according to the intensity of external disturbance and changes in organizational characteristics, so as to offset the error caused by external disturbance and model uncertainty and ensure control accuracy.

[0058] Stability Constraints: The robust impedance filter is constrained based on the Lyapunov stability criterion. A Lyapunov energy function is constructed. By proving the negative definiteness of the function, it is ensured that the contact force tracking error can maintain the uniformly ultimately bounded (UUB) characteristic even when the tissue properties change drastically (such as tissue hardening due to heat during ablation surgery, with stiffness changes ranging from 100 to 1000 N / m). Force fluctuations are strictly controlled within the millinewton range of ±50 mN, meeting the force control accuracy requirements of clinical scanning.

[0059] Safety Redundancy Logic: The robust impedance filter incorporates physical interaction safety redundancy logic, which uses an exponential decay function (with a decay coefficient of 0.5-0.8) to perform weighted smoothing on the robotic arm's motion sequence, generating a coherent motion sequence and completely eliminating motion stuttering phenomena commonly found in traditional segmented control. Simultaneously, when external disturbance torque undergoes abnormal abrupt changes (such as a patient's sudden muscle contraction with a torque change exceeding 5 N·m), the continuous integral term with saturation constraints automatically limits the update rate of the virtual displacement (not exceeding 0.1 mm / ms), preventing the ultrasound probe from causing excessive pressure on the human body due to accidental triggering and ensuring human-machine interaction safety.

[0060] The working principle of a robust impedance filter is as follows: it suppresses integral saturation error through a continuous integral term with saturation constraints, uses robust control terms to offset external disturbances and model uncertainties, and combines safety redundancy logic to achieve motion smoothing and safety protection. The three work together to improve the control accuracy, robustness and safety of the system.

[0061] Step S5, Multi-level Impedance Adjustment Strategy: Based on the real-time feedback from the six-dimensional force / torque sensor, the system's operating mode is switched. The operating modes include free motion mode (high stiffness control mode) and contact scanning mode (compliant control mode), achieving a synergy between rapid ultrasound probe approach and safe scanning. The specific switching logic and control strategy are as follows:

[0062] When the ultrasound probe is in the free movement stage without contacting human tissue, the contact force signal collected by the six-dimensional force / torque sensor is less than the preset threshold, and the system automatically switches the working mode to the free movement mode. In the free movement mode, the system uses high stiffness impedance parameters (such as setting a high value for virtual stiffness) to guide the ultrasound probe to quickly and accurately reach the target initial point along a preset coarse path.

[0063] When the six-dimensional force / torque sensor detects that the contact force between the ultrasound probe and human tissue reaches the preset threshold (the preset threshold can be dynamically adjusted according to the scanning site and the patient's physical condition, with a conventional value of 0.8-1.2N and preferably 1N), the system automatically switches the working mode to the contact scanning mode. At this time, the robust impedance filter officially intervenes to control the system, so as to suppress the impact force at the moment of initial contact and avoid damage to the subject's skin tissue and ultrasound array sensor due to hard collision. In contact scanning mode, the robust impedance filter calculates the current force deviation in real time based on the preset time-varying pressure curve and automatically adjusts the normal displacement compensation amount through a continuous integral term with saturation constraints. Subsequently, the system processes the ultrasound image visual feedback based on image-based visual servoing (IBVS), spatially decouples the normal displacement compensation amount output by the robust impedance filter from the tangential scanning speed command, and converts the force perception deviation into the desired joint speed command at the end of the robotic arm by updating the image Jacobian matrix in real time. This drives the ultrasound probe to smoothly slide along the anatomical contour of human tissue while maintaining constant or specific time-varying pressure, avoiding motion stagnation or position drift caused by excessive local impedance.

[0064] Step S6, Time-varying Force Tracking and Dynamic Response: During the scanning process, the system injects time-varying waveforms (such as sine waves or smooth trapezoidal waves) into the reference force signal to drive the robust impedance filter to generate a corresponding dynamic response, thereby achieving high-precision tracking and control of time-varying contact forces.

[0065] Because of its strong anti-interference capabilities, the RISATE algorithm can filter out electromagnetic noise generated by the ablation device and transient muscle tremors caused by pain in the subject, thus preventing interference with the control system. Through the adaptive gain term in the robust impedance filter, the system can significantly improve the tracking speed and overshoot suppression capability of time-varying contact forces, ensuring that probe pressure can accurately reproduce the preset physical interaction process even within a very short time span. This highly controlled interaction not only helps to acquire high-quality continuous ultrasound cross-sectional images but also provides a reliable data foundation for assessing the degree of tissue ablation through mechanical response.

[0066] The ultrasonic robot autonomous scanning control method based on robust impedance filtering according to the embodiments of the present invention has the following advantages:

[0067] 1. Abandoning the traditional single constant pressure control strategy of ultrasound robots, by constructing a second-order impedance dynamics model, virtual mass, virtual damping, and virtual stiffness parameters can be flexibly adjusted to accurately simulate the variable pressing feel of experienced physicians scanning different anatomical sites; at the same time, relying on the injection of time-varying waveforms of reference force signals, it can achieve precise tracking of regular time-varying contact forces such as sine waves and trapezoidal waves, effectively adapting to dynamic changes in tissue characteristics such as human breathing fluctuations, muscle contractions, and thermal hardening of ablation tissues, meeting the force control needs of complex clinical tasks such as ablation surgery guidance and angiography-specific examinations.

[0068] 2. There is no need to accurately reconstruct prior information of the environmental surface in advance. Even if the subject has slight displacement of body position or local tissue morphology changes, the posture deviation can be corrected in real time through the six-dimensional force / torque sensor force feedback and image vision servoing. This avoids the drastic fluctuation of contact force caused by the mismatch between the robot and the environmental coordinate system, and greatly improves the robustness and fault tolerance of the system in unstructured clinical environments.

[0069] 3. By introducing a continuous integral term with saturation constraints to construct a robust impedance filter, combined with Lyapunov stability constraints, the shortcomings of traditional PID and simple impedance control in handling nonlinear time-varying forces, such as significant time lag and large steady-state error, are overcome. Force fluctuations can be controlled with millinewton precision, while avoiding the integral saturation (windup) problem of traditional integral control. With adaptive gain design, the tracking response speed and overshoot suppression capability of time-varying forces are significantly improved, accurately reproducing the dynamic pressure techniques of expert physicians.

[0070] 4. By spatially decoupling the normal displacement compensation amount and tangential scanning speed command output by the robust impedance filter through image-based visual servoing, it can adaptively and autonomously slide and scan to conform to the anatomical contour of human tissue, effectively avoiding motion stagnation and position drift caused by excessive local impedance, ensuring the continuity and conformity of the scanning path, and improving the continuity of ultrasound imaging and the stability of clinical scanning.

[0071] like Figure 2 As shown, the present invention also provides an autonomous scanning control system for an ultrasonic robot based on robust impedance filtering, comprising:

[0072] Hardware execution module 1 includes a six-degree-of-freedom industrial robot, an ultrasonic probe installed at the end of the robotic arm of the six-degree-of-freedom industrial robot, a six-dimensional force / torque sensor coupled between the ultrasonic probe and the flange of the robotic arm, as well as a supporting control module, ultrasonic imaging module and data acquisition module.

[0073] Calibration module 2 is used to establish the calibration relationship between the robot end effector coordinate system, the force sensor coordinate system, and the ultrasonic image coordinate system;

[0074] Impedance modeling module 3 is used to construct a second-order impedance dynamic model, which abstracts the physical contact behavior between the ultrasound probe and human tissue into a dynamic coupling system that includes mass, damping, and spring characteristics. By adjusting the virtual dynamic parameters, the compliance of the ultrasound probe in the direction of force is set.

[0075] Robust impedance filtering module 4 is used to filter the contact force deviation using robust integral saturation error control theory and output the normal expected displacement compensation amount.

[0076] Impedance adjustment module 5 is used to switch the system's operating mode based on real-time feedback from the six-dimensional force / torque sensor;

[0077] The visual servo module 6 uses an image visual servo algorithm to process the visual feedback of the ultrasound image and spatially decouples the normal displacement compensation amount output by the robust impedance filter from the tangential scanning speed command.

[0078] The time-varying force tracking module 7 is used to inject a time-varying waveform into the reference force signal to drive the robust impedance filter to generate a corresponding dynamic response.

[0079] The ultrasonic robot autonomous scanning control system based on robust impedance filtering provided in this application embodiment can execute the above method embodiment, and its implementation principle and technical effect are similar, so they will not be described again here.

[0080] Figure 3 This is a schematic diagram of the electronic device used in this invention to implement the autonomous scanning control method for an ultrasonic robot based on robust impedance filtering. The electronic device may include a processor 10, a memory 11, a communication bus 12, and a communication interface 13. It may also include a computer program stored in the memory 11 and executable on the processor 10, such as an autonomous scanning control program for an ultrasonic robot based on robust impedance filtering.

[0081] In some embodiments, the processor 10 may be composed of integrated circuits, such as a single packaged integrated circuit or multiple integrated circuits with the same or different functions, including combinations of one or more central processing units (CPUs), microprocessors, digital processing chips, graphics processors, and various control chips. The processor 10 is the control unit of the electronic device, connecting various components of the entire electronic device through various interfaces and lines. It executes programs or modules stored in the memory 11 (e.g., executing an ultrasonic robot autonomous scanning control program based on robust impedance filtering) and calls data stored in the memory 11 to perform various functions of the electronic device and process data.

[0082] The memory 11 includes at least one type of readable storage medium, including flash memory, portable hard drive, multimedia card, card-type memory (e.g., SD or DX memory), magnetic memory, magnetic disk, optical disk, etc. In some embodiments, the memory 11 can be an internal storage unit of an electronic device, such as a portable hard drive. In other embodiments, the memory 11 can be an external storage device of the electronic device, such as a plug-in portable hard drive, smart media card (SMC), secure digital (SD) card, flash card, etc. Furthermore, the memory 11 can include both internal and external storage units of the electronic device. The memory 11 can be used not only to store application software and various types of data installed on the electronic device, such as the code of an ultrasonic robot autonomous scanning control program based on robust impedance filtering, but also to temporarily store data that has been output or will be output.

[0083] The communication bus 12 can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This bus can be divided into an address bus, a data bus, a control bus, etc. The bus is configured to enable communication between the memory 11 and at least one processor 10, etc.

[0084] Communication interface 13 is used for communication between the aforementioned electronic device and other devices, including a network interface and a user interface. Optionally, the network interface may include a wired interface and / or a wireless interface (such as a Wi-Fi interface, Bluetooth interface, etc.), typically used to establish communication connections between the electronic device and other electronic devices. The user interface may be a display, an input unit (such as a keyboard), and optionally, a standard wired or wireless interface. Optionally, in some embodiments, the display may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen, etc. The display may also be appropriately referred to as a screen or display unit, used to display information processed in the electronic device and to display a visual user interface.

[0085] Figure 3 Only electronic devices with components are shown; those skilled in the art will understand that... Figure 3The structure shown does not constitute a limitation on the electronic device and may include fewer or more components than shown, or combine certain components, or have different component arrangements.

[0086] For example, a power supply, although not shown, may also include a power source (such as a battery) to power various components. Preferably, the power supply can be logically connected to at least one processor 10 via a power management device, thereby enabling functions such as charging management, discharging management, and power consumption management. The power supply may also include one or more DC or AC power sources, recharging devices, power fault detection circuits, power converters or inverters, power status indicators, and other arbitrary components. The electronic device may also include various sensors, Bluetooth modules, Wi-Fi modules, etc., which will not be elaborated further here.

[0087] It should be understood that the embodiments are for illustrative purposes only and are not limited to this structure in the scope of the patent application.

[0088] The ultrasonic robot autonomous scanning control program based on robust impedance filtering, stored in memory 11 of the electronic device, is a combination of multiple computer programs. The specific implementation method of the aforementioned computer programs by processor 10 can be found in [reference needed]. Figure 1 The descriptions of the relevant steps in the corresponding embodiments are not repeated here.

[0089] Furthermore, if the modules / units integrated into an electronic device are implemented as software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium. The computer-readable storage medium can be volatile or non-volatile. For example, a computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, and read-only memory (ROM).

[0090] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor of an electronic device, can perform the following functions: Figure 1 The flowchart illustrates the autonomous scanning control method for an ultrasonic robot based on robust impedance filtering.

[0091] In the several embodiments provided by this invention, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and other division methods may be used in actual implementation.

[0092] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0093] Furthermore, the functional modules in the various embodiments of the present invention 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 in the form of hardware plus software functional modules.

[0094] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0095] Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be embraced within the invention. No appended diagram markings in the claims should be construed as limiting the scope of the claims.

[0096] The embodiments of this application can acquire and process relevant data based on artificial intelligence technology. Artificial intelligence (AI) refers to the theories, methods, technologies, and application systems that use digital computers or machines controlled by digital computers to simulate, extend, and expand human intelligence, perceive the environment, acquire knowledge, and use that knowledge to obtain optimal results.

[0097] Furthermore, although the operations of the method of the present invention are described in a specific order in the accompanying drawings, this does not require or imply that these operations must be performed in that specific order, or that all the operations shown must be performed to achieve the desired result. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0098] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

[0099] The present invention has been described above with reference to the accompanying drawings. Obviously, the implementation of the present invention is not limited to the above-described manner. Any improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other situations without modification, are all within the protection scope of the present invention.

Claims

1. An autonomous scanning control method for an ultrasonic robot based on robust impedance filtering, characterized in that, Includes the following steps: An ultrasonic robot hardware system is constructed, comprising a robot, an ultrasonic probe mounted at the end of the robot's robotic arm, and a six-dimensional force / torque sensor coupled between the ultrasonic probe and the flange of the robotic arm. Establish the calibration relationship between the robot end effector coordinate system, the force sensor coordinate system, and the ultrasonic image coordinate system; A second-order impedance dynamics model is constructed, which abstracts the physical contact behavior between the ultrasound probe and human tissue into a dynamic coupling system that includes mass, damping, and spring characteristics. By adjusting the virtual dynamic parameters, the compliance of the ultrasound probe in the direction of force is set. Design a robust impedance filter based on robust integral saturation error control theory; Based on the real-time feedback from the six-dimensional force / torque sensor, the system switches between two operating modes: free motion mode and contact scanning mode. In free motion mode, the ultrasound probe is guided to reach the target initial point along a preset path. In contact scanning mode, the normal displacement compensation amount output by the robust impedance filter is spatially decoupled from the tangential scanning speed command. By updating the image Jacobian matrix in real time, the force perception deviation is converted into the desired joint speed command at the end of the robotic arm, driving the ultrasound probe to achieve smooth sliding scanning along the anatomical contour of human tissue. During the scanning process, the robust impedance filter is driven to generate a corresponding dynamic response by injecting a time-varying waveform into the reference force signal.

2. The method for autonomous scanning control of an ultrasonic robot based on robust impedance filtering according to claim 1, characterized in that, The robust impedance filter introduces a continuous integral term with saturation constraints to compensate for uncertainties in environmental stiffness and nonlinear disturbances.

3. The ultrasonic robot autonomous scanning control method based on robust impedance filtering according to claim 1, characterized in that, The robust impedance filter is constrained based on the Lyapunov stability criterion.

4. The ultrasonic robot autonomous scanning control method based on robust impedance filtering according to claim 1, characterized in that, The adaptive gain term in the robust impedance filter is used to adjust the tracking speed and overshoot suppression capability of the time-varying contact force.

5. The ultrasonic robot autonomous scanning control method based on robust impedance filtering according to claim 1, characterized in that, The robust impedance filter incorporates physical interactive safety redundancy logic and uses an exponential decay function to perform weighted smoothing on the robotic arm's motion sequence.

6. The ultrasonic robot autonomous scanning control method based on robust impedance filtering according to claim 1, characterized in that, The step of switching the system's operating mode based on real-time feedback from the six-dimensional force / torque sensor includes: When the ultrasound probe is in the free movement stage without contacting human tissue, the system's working mode is switched to the free movement mode; when the six-dimensional force / torque sensor detects that the contact force between the ultrasound probe and human tissue reaches a preset threshold, the system's working mode is switched to the contact scanning mode.

7. The method for autonomous scanning control of an ultrasonic robot based on robust impedance filtering according to claim 1, characterized in that, In the contact scanning mode, the visual feedback of the ultrasound image is processed based on the image visual servo processing to spatially decouple the normal displacement compensation amount output by the robust impedance filter from the tangential scanning speed command.

8. The method for autonomous scanning control of an ultrasonic robot based on robust impedance filtering according to claim 1, characterized in that, The expression for the second-order impedance dynamics model is as follows: ; Where Md is virtual mass, Bd is virtual damping, Kd is virtual stiffness, x is the actual position of the probe, x˙ is the actual velocity of the probe, x¨ is the actual acceleration of the probe, xd is the desired position of the probe, x˙d is the desired velocity of the probe, x¨d is the desired acceleration of the probe, Fe is the actual contact force, and Fd is the desired contact force.

9. The method for autonomous scanning control of an ultrasonic robot based on robust impedance filtering according to claim 1, characterized in that, The time-varying waveform is a sine wave or a smooth trapezoidal wave.

10. An autonomous scanning control system for an ultrasonic robot based on robust impedance filtering, used to execute the autonomous scanning control method for an ultrasonic robot based on robust impedance filtering as described in any one of claims 1 to 9, characterized in that, include: The hardware execution module includes a robot, an ultrasonic probe installed at the end of the robot's robotic arm, and a six-dimensional force / torque sensor coupled between the ultrasonic probe and the robotic arm flange. The calibration module is used to establish the calibration relationship between the robot end effector coordinate system, the force sensor coordinate system, and the ultrasonic image coordinate system. Impedance modeling module is used to construct a second-order impedance dynamic model, which abstracts the physical contact behavior between the ultrasound probe and human tissue into a dynamic coupling system that includes mass, damping, and spring characteristics. By adjusting the virtual dynamic parameters, the compliance of the ultrasound probe in the direction of force is set. The robust impedance filtering module is used to filter the contact force deviation based on the robust integral saturation error control theory and output the normal expected displacement compensation amount. An impedance adjustment module is used to switch the system's operating mode based on real-time feedback from the six-dimensional force / torque sensor. The visual servo module uses an image visual servo algorithm to process the visual feedback of the ultrasound image and spatially decouples the normal displacement compensation amount output by the robust impedance filter from the tangential scanning speed command. The time-varying force tracking module is used to inject a time-varying waveform into the reference force signal to drive the robust impedance filter to generate a corresponding dynamic response.

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