Control device, ventricular assist system, dynamic control method, equipment and readable medium

Abstract

This invention relates to a control device, a ventricular assist system, a dynamic control method, an apparatus, and a readable medium. The control device includes a differential pressure estimation module, a flow rate estimation module, and a flow rate control module. The differential pressure estimation module calculates the current estimated differential pressure based on the current aortic pressure value and a preset differential pressure estimation model. The flow rate estimation module calculates the estimated flow rate based on the current estimated differential pressure. The flow rate control module generates control commands based on the target flow rate, the current estimated flow rate, and differential pressure compensation, and sends the control commands to the actuators. This control device enables cascaded control of flow rate and rotational speed in the ventricular assist system, achieving dual closed-loop control.

Description

[0001] The parent application of this divisional application was filed on November 11, 2022, with application number 202211413803.0, and the invention title is "Control device, ventricular assist system, dynamic control method, equipment and readable medium". Technical Field

[0002] This invention relates to medical devices for cardiac surgery and design methods, and more particularly to a control device, a ventricular assist system, a dynamic control method, an equipment, and a readable medium. Background Technology

[0003] Heart failure, or HF, is the end-stage of heart disease. It is characterized by impaired cardiac function, preventing the heart from adequately pumping blood back from the veins, leading to venous congestion and insufficient arterial perfusion, thus causing circulatory disorders. Due to the shortage of heart donors, left ventricular assist devices (LVADs) have become an important treatment option for patients with end-stage heart failure.

[0004] LVAD is a powered blood pump that is 6-8 times more efficient than IABP, effectively replacing more than 80% of the heart's work capacity, with a pumping capacity of up to 10L / min.

[0005] In the LVAD-based coupled model control process, due to hardware limitations, many sensors can only obtain information about aortic pressure. However, in the closed-loop control of flow, the current flow value needs to be obtained through the pressure difference between the aorta and the left ventricle in order to perform closed-loop control. Therefore, it is necessary to consider how to estimate the left ventricular pressure through the aortic pressure, output the current pressure difference between the aorta and the left ventricle, and further obtain the current flow.

[0006] For the reasons mentioned above, how to provide a dynamic control method for ventricular assist devices has become a pressing technical problem that needs to be solved. Summary of the Invention

[0007] In view of this, embodiments of the present invention provide a ventricular assist system and a dynamic control method, which can perform piecewise polynomial regression pressure estimation based on the steady-state limit loop curve to obtain the estimated pressure difference between the aorta and the left ventricle, obtain the current estimated flow rate based on the HQ curve of the pump in the left ventricular assist device, feed the estimated flow rate back to the flow controller, enable it to perform PI control based on the estimated flow rate, and improve the dynamic control effect of the flow controller through pressure difference compensation.

[0008] The present invention adopts the following technical solution: In a first aspect, embodiments of the present invention provide a control device for a ventricular assist system, comprising: The differential pressure estimation module is used to calculate the current estimated differential pressure based on the current aortic pressure value and the preset differential pressure estimation model. The flow estimation module is used to calculate the estimated flow rate based on the current estimated pressure difference; The flow control module is used to generate control commands based on the target flow rate, the current estimated flow rate, and differential pressure compensation, and to send the control commands to the actuator; the differential pressure compensation is the error range between the current estimated differential pressure and the simulated differential pressure.

[0009] Secondly, embodiments of the present invention provide a ventricular assist system, comprising: It includes sensors, control devices, and axial flow pumps; the sensors include pressure sensors; the control devices include differential pressure estimation modules, flow estimation modules, and flow control modules; the axial flow pumps include motors and impellers; The pressure sensor is used to acquire the current aortic pressure value and send it to the differential pressure estimation module; The differential pressure estimation module is used to calculate the current estimated differential pressure based on the current aortic pressure value and the preset differential pressure estimation model; The flow estimation module is used to convert the current estimated pressure difference into an estimated flow rate; The flow control module is used to generate control commands based on the target flow rate, the current estimated flow rate, and differential pressure compensation, and to send the control commands to the axial flow pump; the differential pressure compensation is the error range between the current estimated differential pressure and the simulated differential pressure.

[0010] Thirdly, embodiments of the present invention provide a dynamic control method for a ventricular assist system, comprising: Obtain the current aortic pressure value; The estimated pressure difference is calculated based on the current aortic pressure value and the preset pressure difference estimation model; The estimated flow rate is obtained by converting the current estimated pressure difference; Control commands are generated based on the target flow rate, the current estimated flow rate, and differential pressure compensation, and then sent to the axial flow pump; the differential pressure compensation is the error range between the current estimated differential pressure and the simulated differential pressure.

[0011] Fourthly, embodiments of the present invention provide an electronic device, comprising: One or more processors; Memory, used to store one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the dynamic control method for the ventricular assist system as described above.

[0012] Fifthly, embodiments of the present invention provide a readable storage medium storing a dynamic control program for a ventricular assist system. When the dynamic control program is executed by a processor, it can implement the dynamic control method for a ventricular assist system as described above.

[0013] One embodiment of the above invention has the following advantages or beneficial effects: The present invention mainly provides a left ventricular assist system and a dynamic control method. The present invention can perform piecewise polynomial regression pressure estimation based on a steady-state limit loop curve, allowing the pressure sensor to obtain only the aortic pressure to obtain the estimated aortic and left ventricular pressure difference. Then, based on the HQ curve, the current estimated flow rate is obtained. The flow controller can perform PI control based on the target flow rate and the estimated flow rate, and improve the dynamic control effect of the flow controller through pressure difference compensation. Simultaneously, flow control and rotational speed are cascaded to achieve dual closed-loop control.

[0014] The further effects of the aforementioned unconventional alternative methods will be explained below in conjunction with specific implementation methods. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below, forming part of the present invention. The illustrative embodiments of the present invention and their descriptions explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings: Figure 1 This is a structural block diagram of a control device for a ventricular assist system provided in one embodiment of the present invention; Figure 2 This is a structural block diagram of a left ventricular assist system provided in one embodiment of the present invention; Figure 3 A flowchart of a dynamic control method based on a left ventricular assist system provided in one embodiment of the present invention; Figure 4 A block diagram of the coupling system structure of the left ventricular assist system and the blood circulation system provided in one embodiment of the present invention; Figure 5 The relative pressure curves of the aorta and left ventricle at a cardiac cycle of T=0.75S are provided in one embodiment of the present invention. Figure 6 The relative curves of the aorta and pressure gradient at a cardiac cycle T=0.75S are provided in one embodiment of the present invention. Figure 7 A time series segmentation of aortic pressure at a cardiac cycle T=0.75S is provided as an embodiment of the present invention; Figure 8 for Figure 7 A segmented diagram of the curve; Figure 9 This is a schematic diagram of the polynomial fitting curve segment "*" when the heart rate period T=0.75S is provided in one embodiment of the present invention; Figure 10 A schematic diagram of the "+" segment of the polynomial fitting curve when the heart rate period T=0.75S is provided in one embodiment of the present invention; Figure 11 This is a schematic diagram of the "0" segment of the polynomial fitting curve when the heart rate period T=0.75S is provided in one embodiment of the present invention; Figure 12 A polynomial fitting curve for a heart rate period T=0.75S provided in one embodiment of the present invention. "Segment diagram; Figure 13 This is a block diagram of the flow control structure of a left ventricular assist system provided in one embodiment of the present invention. Detailed Implementation

[0016] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of the present invention, including various details to aid understanding. These details should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0017] When faced with left ventricular dysfunction such as left ventricular failure or cardiogenic shock, a left ventricular assist device (LVAD) is often implanted in the heart to help the left ventricle pump blood into the aorta, ensuring that the amount of venous blood returning to the heart can be adequately discharged outside the heart, and avoiding insufficient perfusion of the arterial system.

[0018] However, due to the structural limitations of the LVAD itself, it cannot obtain the pressure of the left ventricle, but can only obtain the pressure of the aorta. However, in its closed-loop control part of flow, it needs to obtain the current flow value through the pressure difference between the aorta and the left ventricle in order to perform closed-loop control.

[0019] To address the aforementioned shortcomings, embodiments of the present invention provide a control device 100 for a ventricular assist system, such as... Figure 1 The control device 100 includes a differential pressure estimation module 110, a flow estimation module 120, and a flow control module 130.

[0020] In one embodiment of the present invention, the control device 100 is used for a left ventricular assist system and controls its rotational speed and flow rate; specifically, the left ventricular assist system includes at least a left ventricular assist device (LVAD).

[0021] In one embodiment of the present invention, the differential pressure estimation module 110 is used to calculate the current estimated differential pressure based on the current aortic pressure value and a preset differential pressure estimation module.

[0022] In one embodiment of the present invention, the left ventricular assist system is provided with at least one sensor capable of acquiring aortic pressure (AoP) data and transmitting the aortic pressure data to the differential pressure estimation module 110 for calculation.

[0023] In one embodiment of the present invention, the differential pressure estimation module 110 is further used to calculate simulation data; this simulation data is obtained from the simulation of a coupled system model of the ventricular assist system, and the simulated coupled system model includes the limiting loop curves of aortic pressure AoP and the differential pressure DP between the aorta and left ventricle, such as... Figure 6 In this embodiment, the coupling system refers to the system formed by coupling the left ventricular assist system with the left ventricle.

[0024] In one embodiment of the present invention, the simulation of the coupled system can be performed using simulation software such as Matlab, LabVIEW or Ansys. By inputting initial conditions into the simulation software, the simulation results of the model can be output. Specifically, the data input for the initial conditions can be selected as laboratory data.

[0025] Specifically, the aforementioned coupled system model can perform simulations based on the heartbeat cycle, outputting time series, aortic pressure (AoP) sequence, and left ventricular pressure (LVP) sequence data for that heartbeat cycle. Based on the data output after simulation for that heartbeat cycle, the coupled system model further outputs the limiting loop curves of aortic pressure (AoP) versus pressure difference (DP), such as... Figure 6 .

[0026] In one embodiment of the present invention, the left ventricular assist system is provided with at least a sensor capable of acquiring heart rate data and transmitting the real-time heart rate data to the differential pressure estimation module 110. The differential pressure estimation module 110 can calculate the real-time heartbeat cycle based on the real-time heart rate and output the limit loop curves of aortic pressure AoP and differential pressure DP according to different heartbeat cycles.

[0027] In one embodiment of the present invention, the differential pressure estimation module 110 is further configured to calculate the current estimated differential pressure based on the above differential pressure estimation model; the differential pressure estimation model is obtained by segmenting the limit cycle curve and performing polynomial regression.

[0028] In one embodiment of the present invention, the differential pressure estimation model includes the relationship between aortic pressure AoP and differential pressure DP; the above polynomial regression includes: dividing the limit loop curve into 4 segments according to the slope change, with the endpoints of each segment as segmentation nodes; and performing polynomial regression on each segment separately.

[0029] Specifically, after obtaining the limiting loop curve of aortic pressure AoP versus pressure difference DP, the limiting loop curve is segmented in the coordinate system. At the segmentation points, the slope of the limiting loop curve will change significantly, such as... Figure 8 Therefore, based on the slope change of the limit cycle curve, it can be divided into 4 curve segments, and the intersection of adjacent curve segments (that is, the boundary points at both ends of each curve segment) is used as segmentation nodes; the data of arterial pressure AoP and pressure difference DP represented by each curve segment are subjected to polynomial regression.

[0030] In one embodiment of the present invention, the differential pressure estimation module 110 can perform piecewise and polynomial regression on multiple sets of limit cycle curves based on different heartbeat cycles, with each set of limit cycle curves corresponding to a set of polynomial parameters and a set of piecewise nodes.

[0031] After the sensor transmits the real-time heart rate to the differential pressure estimation module 110, the differential pressure estimation module 110 can select the corresponding polynomial coefficient parameters and the segmentation nodes of the limit loop curve based on the current aortic pressure value and the current heartbeat cycle, and obtain the current estimated differential pressure based on the differential pressure estimation model.

[0032] In one embodiment of the present invention, the differential pressure estimation module 110 is further configured to calculate the error range between the current estimated differential pressure and the simulated differential pressure based on simulation data.

[0033] In one embodiment of the present invention, the flow estimation module 120 is used to calculate the estimated flow rate based on the current estimated pressure difference.

[0034] In one embodiment of the present invention, the estimated pressure difference is converted into the current estimated flow rate via the HQ curve, and the estimated flow rate and target flow rate are fed back to the flow control module 130. Specifically, the HQ curve is derived based on the hydraulic characteristics of the pump and the similarity theorem, reflecting the relationship between the rotational speed, flow rate, and pressure difference of the axial flow pump in the left ventricular assist device. Therefore, the HQ curve is constrained by the structure of the pump itself and is deterministic, and can be used directly without recalculation. After calculating the estimated pressure difference, the estimated flow rate can be obtained through the HQ curve.

[0035] In one embodiment of the present invention, the flow control module 130 is used to generate feedback control commands based on the target flow rate, the current estimated flow rate, and differential pressure compensation, and to issue the feedback control commands to the actuator. In this embodiment, the differential pressure compensation targets the error range between the calculated current estimated differential pressure and the simulated differential pressure. In this embodiment, the actuator is the axial flow pump in the left ventricular assist device.

[0036] In one embodiment of the present invention, the flow control module 130 includes a first flow control module 131 and a second flow control module 132; the first flow control module 131 is used to send a target speed command to the second flow control module 132 based on the target flow, the current estimated flow, and the differential pressure compensation production target speed command; the second flow control module 132 is used to issue control commands to the actuator, and finally realize dual closed-loop control of flow and speed.

[0037] like Figure 2 , Figure 13 This invention provides a left ventricular assist system, which includes a sensor 200, a control device 100, and an axial flow pump 300. The sensor 200 includes a pressure sensor 210; the control device 100 includes a differential pressure estimation module 110, a flow estimation module 120, and a flow control module 130; and the axial flow pump 300 includes a motor and an impeller.

[0038] In one embodiment of the present invention, the left ventricular assist system further includes a heart rate sensor 220, and, apart from the heart rate sensor 220, other structures can be regarded as one of the components of the left ventricular assist device LVAD. The outflow tract of the left ventricular assist device is disposed in the aorta, and the inflow tract is disposed in the left ventricle.

[0039] In one embodiment of the present invention, a pressure sensor 210, a control device 100 and an axial flow pump 300 are arranged in sequence. The pressure sensor 210 can acquire aortic pressure AoP data and send it to the differential pressure estimation module 110 in the control device 100.

[0040] In one embodiment of the present invention, the heart rate sensor 220 is able to acquire current heart rate data and send it to the differential pressure estimation module 110 in the control device 100.

[0041] In one embodiment of the present invention, the differential pressure estimation module 110 is used to calculate the current estimated differential pressure based on the current aortic pressure value and a preset differential pressure estimation model.

[0042] In one embodiment of the present invention, the differential pressure estimation module 110 is further configured to calculate the error range between the estimated differential pressure and the simulated differential pressure according to different heartbeat cycles.

[0043] In one embodiment of the present invention, the flow estimation module 120 is used to obtain the estimated flow rate based on the current estimated pressure difference.

[0044] In one embodiment of the present invention, the estimated pressure difference is converted into the current estimated flow rate through the HQ curve, and the estimated flow rate and the target flow rate are fed back to the flow control module 130.

[0045] In one embodiment of the present invention, the flow control module 130 is used to generate control commands based on the target flow rate, the current estimated flow rate and differential pressure compensation, and send the control commands to the axial flow pump 300.

[0046] In one embodiment of the present invention, the flow control module 130 includes a first flow control module 131 and a second flow control module 132; the first flow control module 131 is used to send a target speed command to the second flow control module 132 based on the target flow, the current estimated flow, and the differential pressure compensation production target speed command; the second flow control module 132 is used to issue control commands to the axial flow pump 300.

[0047] refer to Figure 3 This invention provides a dynamic control method based on a left ventricular assist system, comprising: Step 410: Obtain the current aortic pressure value.

[0048] In one embodiment of the present invention, the aortic pressure value is detected in real time by the pressure sensor 210 and transmitted to the differential pressure estimation module 110 in the control device 100.

[0049] Step 420: Calculate the current estimated pressure difference based on the current aortic pressure value and the preset pressure difference estimation model.

[0050] In one embodiment of the present invention, step 420 further includes the following steps: Step 421: Establish and simulate the coupled system model of the left ventricular assist device, and output the limit loop curve of aortic pressure AoP and pressure difference DP between the aorta and left ventricle.

[0051] Taking both systemic and pulmonary circulation into account, the blood in the human circulatory system flows sequentially through the left atrium, left ventricle, aorta, arteries of all levels, veins of all levels, vena cava, right atrium, pulmonary artery, pulmonary vein, and finally returns to the left atrium.

[0052] In one embodiment of the present invention, a left ventricular assist device is disposed between the left ventricle and the aorta. Its main structure includes a control device 100, a motor, an impeller, a pressure sensor 200, etc. The pressure sensor 200 can acquire the aortic pressure AoP. The drive motor outputs a corresponding rotation speed according to the command issued by the flow control module 130 of the control device 100. The impeller can pump blood in the left ventricle into the aorta in order to provide the flow required for circulation. The motor and the impeller together form an axial flow pump 300.

[0053] like Figure 4 In the coupled system of LVAD and blood circulation, a coupled system model is established based on the physical models of both, the hydraulic properties of LVAD, and the similarity theorem. The model is as follows: ,in, , These represent the pressure in each cavity of the circulatory system. This indicates the pump flow rate (PF). Indicates the motor speed. Let... , If we denote the nonlinear term, then the coupled system model can be written as follows: This model reflects the relationship between the rotational speed, flow rate, and pressure in each chamber of the LVAD.

[0054] In some alternative embodiments of the present invention, the LVAD can also be connected in parallel to the apex of the left ventricle and both ends of the aorta. There are also different ways to construct the physical model of the circulatory system, such as using the double elastic chamber model proposed by Goldwyn et al. Therefore, the coupled system model of the LVAD and the blood circulation system can be deformed or other adjustments can be made according to the actual physical model constructed.

[0055] In one embodiment of the present invention, taking a heart rate of 80 beats per minute as an example, the corresponding heartbeat cycle is 0.75 seconds. During this time, it takes 0.75 seconds from the start of one heartbeat to the start of the next, within which one complete circulation of blood throughout the body can be achieved. Those skilled in the art should understand that the heart rate of a normal adult varies depending on their physiological / pathological state, generally fluctuating between 0.65 seconds and 1 second. In this embodiment, only 0.75 seconds is used as an example for simulation.

[0056] The time series of the coupled system model simulation at heart rate T=0.75s, the aortic pressure (AoP) sequence, and the left ventricular pressure (LVP) sequence were used as output data. These output data were plotted in a coordinate system, with the x-axis representing aortic pressure (AoP) and the y-axis representing left ventricular pressure (LVP). Figure 5 As shown, it can be determined that as the coupled system gradually stabilizes, the aortic pressure AoP and the left ventricular pressure LVP gradually exhibit steady-state limit loop state curves.

[0057] In one embodiment of the present invention, the simulation of the coupled system can be performed using simulation software such as Matlab, LabVIEW or Ansys. By inputting initial conditions into the simulation software, the simulation results of the model can be output.

[0058] Since pressure difference is the driving force for fluid flow, in the closed-loop control part of the flow rate, the current flow rate value can only be obtained by obtaining the pressure difference between the aorta and the left ventricle for closed-loop control. Therefore, it is necessary to consider how to estimate the left ventricular pressure through the aortic pressure.

[0059] In one embodiment of the present invention, based on the data output from the model simulation at a heart rate of T=0.75s, the pressure difference between the aorta and the left ventricle is calculated to obtain the pressure difference DP between the aorta and the left ventricle. Plotting the aortic pressure AoP and the pressure difference DP in a coordinate system yields the limiting loop curve of the aortic pressure AoP versus the pressure difference DP, as shown below. Figure 6 The x-axis represents the aortic pressure AoP, and the y-axis represents the pressure difference between the aorta and the left ventricle DP.

[0060] In some alternative embodiments of the present invention, when simulating the model, even if the initial heart rate cycle is not 0.75s, the data obtained after the model simulation (time series, aortic pressure AoP series, left ventricular pressure LVP series) can still present a steady-state limit loop state curve in the coordinate system. Furthermore, by calculating the difference between the aortic and left ventricular pressures, the curve of aortic pressure AoP and pressure difference DP obtained in the coordinate system also presents a limit loop curve.

[0061] Step 422: Divide the limit cycle curve into segments and determine the segment nodes. Perform polynomial regression on each curve segment to obtain the polynomial coefficient parameters and pressure difference estimation model.

[0062] After obtaining the limiting loop curve of aortic pressure AoP and pressure difference DP between the aorta and left ventricle in step 421, the limiting loop curve is segmented in the coordinate system. At the segmentation position, the slope of the limiting loop curve will change significantly. Therefore, based on the change in the slope of the limiting loop curve, it can be divided into 4 curve segments. The intersection of adjacent curve segments (that is, the boundary points at both ends of each curve segment) is used as the segmentation node. The data of arterial pressure AoP and pressure difference DP represented by each curve segment are subjected to polynomial regression.

[0063] In one embodiment of the present invention, the four segmentation nodes are respectively The model's output time series and aortic pressure (AoP) series are mapped onto a coordinate system, and the four segment nodes are mapped to this coordinate system respectively, such as... Figure 7 This allows us to determine the rising and falling trends of aortic pressure AoP corresponding to the four segments of the limit loop curve.

[0064] In one embodiment of the present invention, the four curve segments formed by dividing the limit cycle curve are respectively marked with "*", "+", " ... The symbols “o” indicate that the signs at both ends of each curve segment are the segmentation nodes, such as… Figure 8 The four curves were subjected to polynomial regression. Those skilled in the art will understand that the higher the regression order, the better the fit, but the lower the efficiency. To achieve a balance between fit and efficiency, the polynomial order was set to 3.

[0065] Specifically, use The "*" part of the fitted curve; using The "+" portion of the fitted curve; using The "o" portion of the fitted curve; using The fitted curve's " The section describes how, after fitting the four curves separately, a piecewise estimation curve of aortic pressure AoP versus pressure difference DP is obtained, as shown below. Figures 9-12 These four curves were used as reference pressure curves for T=0.75s.

[0066] Segment nodes, Figure 7 By integrating the rising and falling trends of AoP and the polynomial regression equation, a pressure differential estimation model can be obtained, which is the corresponding relationship between aortic pressure AoP and pressure differential DP when the heart rate cycle T=0.75s: (1) Depend on Figure 7 It can be seen that when the value of aortic pressure AoP is determined, it may be mapped to different segments of the limiting loop curve. Therefore, in the above equation (1), and Let AoP represent the current aortic pressure AoP and the aortic pressure AoP at the previous moment, respectively. This is used to determine whether the trend of the aortic pressure AoP at this moment is increasing or decreasing, so as to ensure that the correct polynomial can be selected when calculating the estimated pressure difference according to Equation (1), and to ensure the accuracy of the calculated data.

[0067] Furthermore, after performing polynomial regression on the four curve segments respectively, the coefficient parameter values ​​of the polynomial when the heart rate period T=0.75s can be obtained, as follows: , , , , , , , , , , , , , , , .

[0068] Those skilled in the art should understand that when the input heart rate period T during simulation is not 0.75s, the above steps are the same, but the obtained piecewise nodes and polynomial coefficient parameters should be recalculated accordingly to obtain a new set of data.

[0069] Step 423: Obtain the current aortic pressure value and obtain the current estimated pressure difference based on the pressure difference estimation model.

[0070] In one embodiment of the present invention, the current aortic pressure AoP is obtained by the pressure sensor 200 of the LVAD, and the estimated pressure difference at this time is calculated based on the above formula (1). The current time and the corresponding estimated pressure difference are input to the flow estimation module 120 of the control device 100 of the LVAD.

[0071] Those skilled in the art should understand that the user's heart rate cycle T is considered to be 0.75s and does not change with physiological / pathological conditions. In this embodiment, it is not necessary to obtain the user's heart rate when the LVAD is working. Instead, the user's heart rate has been measured before the LVAD is used, and its corresponding heart rate cycle T is used as the initial condition for model simulation. Finally, fixed polynomial coefficient parameters and the piecewise nodes of the limit cycle curve are calculated. Therefore, in this embodiment, the estimated pressure difference can be calculated by measuring the aortic pressure AoP when the LVAD is working.

[0072] Step 424: Obtain the error range between the estimated differential pressure value and the simulated differential pressure based on the simulation data, and output it to the flow control module 130.

[0073] Referring to step 421 above, after simulating the coupled system model and outputting data, the simulated pressure difference value DP can be calculated. The simulated pressure difference value DP is regarded as the actual pressure difference value. The difference between the actual pressure difference value and the estimated pressure difference value calculated in step 423 is calculated to obtain the error range between the estimated pressure difference value and the actual pressure difference value.

[0074] In this embodiment, since the heart rate cycle T = 0.75s, the error range between the estimated pressure difference and the actual pressure difference can be calculated as follows: mmHg.

[0075] In one embodiment of the present invention, the error range between the estimated pressure difference and the actual pressure difference in the four curve segments is calculated respectively: in the curve segment from 100.5 to 91, the maximum error is 3.4247; in the curve segment from 91 to 55.5, the maximum error is 0.4720; in the curve segment from 55.5 to 54, the maximum error is 1.9740; and in the curve segment from 54 to 100.5, the maximum error is 1.6917.

[0076] Those skilled in the art should understand that when the initial heartbeat period T of the coupled system model is not 0.75s during simulation, it is necessary to recalculate the error range between the estimated pressure difference and the actual pressure difference.

[0077] Step 430: Obtain the estimated flow rate based on the current estimated pressure difference.

[0078] In one embodiment of the present invention, the estimated pressure difference is converted into the current estimated flow rate through the HQ curve and fed back to the flow control module 130 of the control device 100.

[0079] Specifically, the HQ curve is derived based on the pump's hydraulic characteristics and similarity theorem. It reflects the relationship between the pump's speed, flow rate, and pressure difference. Therefore, the HQ curve is constrained by the pump's structure and is deterministic, requiring no further calculation and can be used directly. After calculating the estimated pressure difference, the estimated flow rate can be obtained from the HQ curve.

[0080] Step 440: Generate control commands based on the target flow rate, the current estimated flow rate, and differential pressure compensation, and send the control commands to the axial flow pump.

[0081] In one embodiment of the present invention, the control command is a PI control command. PI control can control the controlled object by linearly combining the proportional and integral components of the control deviation between the given value and the actual output value to form a control quantity. Reflected in LVAD, the formula for PI control is: (2) in, This is the output, used to change the target speed; the current is positively correlated with the speed of the drive motor. To estimate the flow rate, For target traffic, The error obtained in step 424 and The coefficient is obtained empirically.

[0082] Through the above formula (2), flow control and speed control can be cascaded to achieve dual closed-loop control, such as... Figure 13 Meanwhile, based on the error between the calculated estimated pressure difference and the simulated pressure difference introduced in equation (2), It can improve the dynamic control effect of the control device 100 through differential pressure compensation.

[0083] Since the heart rate cycle in the above embodiments is unique and deterministic, only the user's aortic pressure (AoP) needs to be obtained when controlling the flow of the axial flow pump. However, different physiological states, ages, pathological conditions, medications, and emotional changes in users can all cause changes in heart rate, resulting in a non-unique and deterministic heart rate cycle. Therefore, in another embodiment of the present invention, a more precise dynamic control method for a left ventricular assist system is provided, the method comprising: Step 510: Obtain the current aortic pressure value.

[0084] Step 520: Calculate the current estimated pressure difference based on the current aortic pressure value and the current pressure difference estimation model.

[0085] Step 521: Establish a coupled system model of the left ventricular assist device and perform multiple simulations based on different heartbeat cycles, outputting multiple sets of limit loop curves of aortic pressure AoP and pressure difference DP between the aorta and left ventricle.

[0086] In one embodiment of the present invention, the construction of the coupled system model is the same as in step 421 above. However, during the simulation, the initial conditions are changed, that is, different heartbeat cycles T, so that the model is simulated multiple times and the data is output respectively. Based on the multiple sets of output data, the limit loop curves of the aortic pressure AoP and the pressure difference DP between the aorta and the left ventricle are calculated respectively.

[0087] Given that the heartbeat cycle generally fluctuates between 0.65s and 1s, in this embodiment, the heartbeat cycle is selected as 0.65s, 0.7s, 0.75s, 0.8s, 0.85s, 0.9s, 0.95s, and 1s respectively when the model is simulated.

[0088] In some alternative embodiments of the present invention, the heart rate cycle is also further selected or adjusted according to the user's actual physiological / pathological state.

[0089] Step 522: Divide the multiple sets of limit cycle curves into segments and determine the segmentation nodes. Perform polynomial regression on each curve segment. Each set of limit cycle curves corresponds to a set of polynomial coefficient parameters and pressure difference estimation models.

[0090] In one embodiment of the present invention, the limit cycle curve calculated after each simulation is segmented, and then polynomial regression is performed on the segmented curve segments to obtain the polynomial parameter coefficients under different heartbeat cycles. The specific steps are the same as those in step 422 above, and will not be repeated here.

[0091] By integrating the segmented nodes, the rising and falling trends of AoP after each simulation, and the polynomial regression equation, we can obtain the corresponding relationship between aortic pressure AoP and pressure difference DP under different heartbeat cycles, which is the pressure difference estimation model in different heartbeat cycles. The corresponding relationship is the same as the above equation (1), the difference being in the coefficient parameters and in each polynomial. The range of values ​​is different.

[0092] Taking a heart rate cycle of T=0.7s as an example, the corresponding relationship between aortic pressure AoP and pressure difference DP has the following segment nodes: In the curve segment 100.9→91, The coefficient is 292669.6749. The coefficient is -9225.9575. The coefficient is 96.7937. The coefficient is -0.3379; in the curve segment 91→58, The coefficient is 174.4054. The coefficient is -5.7553. The coefficient is 0.0710. The coefficient is -0.000029; in the curve segment 58→55.5, The coefficient is -75521.1826. The coefficient is 4431.9356. The coefficient is -85.4563. The coefficient is 0.5431; in the curve segment 55.5→100.9, The coefficient is -239.5229. The coefficient is 9.9645. The coefficient is -0.1058. The coefficient is 0.000040.

[0093] Taking a heart rate of T=0.8s as an example, the corresponding relationship between aortic pressure AoP and pressure difference DP has the following segment nodes: In the curve segment 100.9→91, The coefficient is 184737.3137. The coefficient is -5831.2027. The coefficient is 61.2255. The coefficient is -0.2138; in the curve segment 91→54, The coefficient is 150.0405. The coefficient is -5.0807. The coefficient is 0.0658. The coefficient is -0.000029; in the curve segment 54→52.5, The coefficient is -155044.1689. The coefficient is 9472.2480. The coefficient is --191.1600. The coefficient is 1.2764; in the curve segment 52.5→100.9, The coefficient is -123.7238. The coefficient is 5.7142. The coefficient is -0.0547. The coefficient is 0.000020.

[0094] Step 523: Obtain the current heart rate cycle and aortic pressure value. Select the corresponding polynomial coefficient parameters and the segmentation nodes of the limit loop curve based on the current heart rate cycle. Obtain the current estimated pressure difference based on the pressure difference estimation model.

[0095] In one embodiment of the present invention, the heart rate cycle is obtained by heart rate conversion. The heart rate is not directly measured by the LVAD, but is detected by other heart rate sensors 220 (such as a wearable heart rate monitor), and the detection data is sent to the LVAD by the sensor.

[0096] After obtaining the current heart rate cycle and aortic pressure AoP from LVAD, the corresponding coefficient parameters and segmentation nodes are determined and selected based on the current heart rate cycle. The estimated pressure difference is obtained based on the relationship between aortic pressure AoP and pressure difference DP. The specific steps are the same as those in step 423 above, and will not be repeated here.

[0097] Step 524: Calculate the error range between the estimated pressure difference and the simulated pressure difference based on different heartbeat cycles.

[0098] When the heartbeat cycle is different, the output results of the simulation model are also different. Therefore, after calculating the estimated pressure difference, it is necessary to calculate the error range between the estimated pressure difference value and the actual pressure difference value based on the data obtained from the simulation of different heartbeat cycles.

[0099] Taking a heart rate cycle of T=0.7s as an example, the maximum estimation error is 3.2055 in the curve segment 100.9→91; 0.4427 in the curve segment 91→58; 2.9651 in the curve segment 58→55.5; and 2.1267 in the curve segment 55.5→100.9.

[0100] Taking a heart rate cycle of T=0.8s as an example, the maximum estimation error is 2.8139 in the curve segment 100.9→91; 0.3229 in the curve segment 91→54; 0.8088 in the curve segment 54→52.5; and 1.2948 in the curve segment 52.5→100.9.

[0101] The specific calculation process is the same as step 424 above, and will not be repeated here.

[0102] Step 530: Obtain the estimated flow rate based on the current estimated pressure difference.

[0103] Step 540: Generate control commands based on the target flow rate and estimated flow rate, and send the control commands to the axial flow pump.

[0104] Specifically, steps 530 and 540 are the same as steps 430 and 440 above, and will not be repeated here.

[0105] This invention, through real-time measurement of the user's heart rate, calculates and estimates the flow rate based on the actual heartbeat cycle, and then achieves dual closed-loop control of flow rate and rotation speed through PI control. This makes the LVAD more closely match the user's actual cardiac physiological state, aiming to obtain a more accurate pumping flow rate, reduce adverse reactions in users, and avoid problems such as LVAD reflux.

[0106] In one embodiment of the present invention, an electronic device is also provided, the electronic device including at least one processor and a memory, the memory being used to store one or more programs, which, when executed by the processor, enable the processor to implement the dynamic control method of the left ventricular assist system as described above.

[0107] In one embodiment of the present invention, a readable storage medium is also provided, on which a dynamic control program based on a ventricular assist system is stored. When the dynamic control program is executed by a processor, it can realize steps 410-440 or steps 510-540.

[0108] It should be noted that the ventricular assist system provided in the above embodiments and the dynamic control method embodiments based on the ventricular assist system belong to the same concept. For details of its specific implementation process, please refer to the method embodiments, which will not be repeated here.

[0109] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0110] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. A control device for a ventricular assist system, characterized in that, include: The differential pressure estimation module is used to acquire the current aortic pressure value collected by the pressure sensor, and calculate the current estimated differential pressure based on the current aortic pressure value and the preset differential pressure estimation model. The pressure difference estimation model is obtained by segmenting the limiting loop curve and performing polynomial regression. The limiting loop curve is the limiting loop curve of the aortic pressure AoP and the pressure difference DP between the aorta and the left ventricle. The flow estimation module is used to calculate the estimated flow rate based on the current estimated pressure difference; The flow control module is used to generate control commands based on the target flow rate, the current estimated flow rate, and differential pressure compensation, and to send the control commands to the actuator; the differential pressure compensation is the error range between the current estimated differential pressure and the simulated differential pressure.

2. The control device according to claim 1, characterized in that, The differential pressure estimation module is also used for: Calculate simulation data; the simulation data is obtained by simulating a coupled system model of the ventricular assist system, and the coupled system model includes the limit cycle curve.

3. The control device according to claim 2, characterized in that, The polynomial regression includes: The limit cycle curve is divided into four segments based on the slope change, with the endpoints of each segment serving as segmentation nodes. Perform polynomial regression on each curve segment separately.

4. The control device according to claim 2, characterized in that, The polynomial regression includes: The limit loop curves of multiple sets of aortic pressure (AoP) and pressure difference (DP) were segmented and subjected to polynomial regression. Each set of limit loop curves corresponds to a set of polynomial parameters and a set of segment nodes.

5. The control device according to claim 4, characterized in that, The differential pressure estimation module is also used for: Based on the current aortic pressure value and the current heart rate cycle, the corresponding polynomial coefficient parameters and the segmentation nodes of the limit loop curve are selected, and the current estimated pressure difference is obtained based on the pressure difference estimation model.

6. The control device according to claim 2, characterized in that, The flow estimation module is also used for: The estimated pressure difference is converted into the current estimated flow rate using the HQ curve, and the current estimated flow rate and the target flow rate are fed back to the flow control module.

7. The control device according to any one of claims 1-6, characterized in that, The flow control module includes a first flow control module and a second flow control module; The first flow control module is used to generate a target speed command based on the target flow rate, the current estimated flow rate, and differential pressure compensation; The first flow control module sends the target speed command to the second flow control module; The second flow control module is used to send control commands to the actuator.

8. The control device according to any one of claims 1-6, characterized in that, The control commands include PI control commands, and the formula for the PI control is: in, This is the output used to change the target rotational speed. To estimate the flow rate, For target traffic, To estimate the error between the differential pressure value and the simulated differential pressure, and These are coefficients obtained empirically.

9. The control device according to any one of claims 1-6, characterized in that, The differential pressure estimation module is also used to calculate the error range between the estimated differential pressure and the simulated differential pressure based on different heartbeat cycles.

10. A ventricular assist system, characterized in that, The device includes a sensor, an axial flow pump, and a control device as described in any one of claims 1-9; the sensor includes a pressure sensor; the control device includes a differential pressure estimation module, a flow estimation module, and a flow control module; the axial flow pump includes a motor and an impeller; the pressure sensor is used to acquire the current aortic pressure value and send it to the differential pressure estimation module; The differential pressure estimation module is used to acquire the current aortic pressure value collected by the pressure sensor, and calculate the current estimated differential pressure based on the current aortic pressure value and the preset differential pressure estimation model. The pressure difference estimation model is obtained by segmenting the limiting loop curve and performing polynomial regression. The limiting loop curve is the limiting loop curve of the aortic pressure AoP and the pressure difference DP between the aorta and the left ventricle. The flow estimation module is used to convert the current estimated pressure difference into an estimated flow rate; The flow control module is used to generate control commands based on the target flow rate, the current estimated flow rate, and differential pressure compensation, and to send the control commands to the axial flow pump; the differential pressure compensation is the error range between the current estimated differential pressure and the simulated differential pressure.

11. An electronic device, characterized in that, include: One or more processors; Memory, used to store one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors perform the functions of the control device for a ventricular assist system as described in any one of claims 1-9.

12. A readable storage medium, characterized in that, The readable storage medium stores a dynamic control program for a ventricular assist system, which, when executed by a processor, enables the functions performed by the control device for a ventricular assist system as described in any one of claims 1-9.

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