Control system and control method for an interventional heart pump

Abstract

The application discloses an interventional heart pump control system and a control method, which comprises an interventional heart pump, wherein the interventional heart pump is connected with a controller through a motor driver; the controller is connected with a physiological monitoring device; the controller is also connected with a computer terminal; the controller is configured to acquire a physiological signal monitored by the physiological monitoring device, obtain a motor control signal according to the physiological signal, a motor speed signal of the interventional heart pump and a set signal, send the motor control signal to the motor driver, and control a rotor rotating speed of the interventional heart pump according to a rotor speed of the motor driver obtained according to the motor control signal. The control algorithm of the interventional heart pump comprises a patient circulation system model and an interventional heart pump model, realizes automatic adjustment and real-time adjustment, and avoids the case that a constant rotating speed cannot adapt to various physiological conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heart pump control, in particular to a control system and control method of an interventional heart pump. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute the prior art.

[0003] Heart failure is a serious heart disease characterized by the inability of the heart to pump enough blood and nutrients to meet the body's metabolic needs. The incidence and mortality of heart failure are high, and it has become a serious health problem worldwide. Current treatments for heart failure include drug therapy, cardiac resynchronization therapy, artificial heart, and heart transplantation. In recent years, with the increasing incidence of cardiovascular diseases, artificial hearts have received widespread attention because they can assist heart failure patients in achieving normal heart pumping function, can be used for long-term heart assistance of patients, or can be used in the temporary transition phase of patients waiting for heart transplantation.

[0004] An artificial heart, also known as a heart pump, is a mechanical device that assists the heart in achieving systemic blood circulation. Its basic principle is to partially or completely replace the pumping function of the heart by imitating or using mechanical methods. Current heart pumps can be divided into extracorporeal, implantable, and interventional according to the use scenario. Extracorporeal and implantable heart pumps have complex surgery and cause greater damage to the patient's heart. Interventional heart pumps can be placed in the patient's aorta through peripheral vascular intervention surgery, thereby providing rapid and non-invasive circulation assistance when the patient's heart pump function fails. The effect is more pronounced for high-risk coronary intervention surgery and acute myocardial infarction-induced cardiogenic shock patients.

[0005] In recent years, the development of interventional heart pumps has mainly focused on fluid and mechanical parts, and these devices mostly run at a constant speed to form a simple open-loop or closed-loop control system, i.e., a doctor sets a certain speed according to the patient's condition. Due to the patient's changing physical condition, this operation may not match the patient's physiological needs, affecting the patient's treatment and recovery, and in severe cases, it can even endanger the patient's life. In addition, during the use of the interventional heart pump, the doctor needs to monitor the patient's physiological condition signals to set the parameters of the interventional heart pump, which cannot achieve real-time and accuracy. SUMMARY

[0006] To solve the problems of the prior art, the present application provides a control system and control method of an interventional heart pump.

[0007] In a first aspect, the present application provides a control system of an interventional heart pump.

[0008] A control system of an interventional heart pump, comprising: an interventional heart pump;

[0009] The interventional heart pump is connected with the controller through a motor driver;

[0010] The controller is connected with a physiological monitoring device;

[0011] The controller is further connected with a computer terminal;

[0012] The controller is configured to: acquire a physiological signal monitored by the physiological monitoring device, obtain a motor control signal according to the physiological signal, a motor speed signal of the interventional heart pump and a set signal, send the motor control signal to the motor driver, and control a rotor rotating speed of the interventional heart pump according to a rotor speed of the motor driver according to the motor control signal.

[0013] In a second aspect, the present application provides a control method of an interventional heart pump;

[0014] A control method of an interventional heart pump, comprising:

[0015] S1: acquiring a set signal; the set signal comprises: a set blood pressure, a set blood flow and a set pulse frequency;

[0016] S2: when executed for the first time, obtaining a required blood flow of a patient according to the set signal and a preset patient blood circulation system model;

[0017] When executed for the first time, obtaining a required blood flow of a patient according to a signal collected by a physiological monitoring device and a preset patient blood circulation system model;

[0018] S3: obtaining a blood flow, an outlet end blood pressure and a blood flow field distribution of the interventional heart pump according to the required blood flow of the patient and a preset blood fluid model;

[0019] S4: obtaining a required motor speed signal according to the blood flow, the outlet end blood pressure, the blood flow field distribution, a real-time motor speed of the interventional heart pump and a preset electromagnetic coupling model; when S4 is executed for the first time, the real-time motor speed of the motor is zero;

[0020] S5: the motor driver compares the real-time motor speed with the required motor speed signal to generate a control signal, the control signal is input into a motor winding of the interventional heart pump to generate an electromagnetic torque, drive the rotor to rotate, drive blood movement through an impeller, and thus realize auxiliary circulation of blood;

[0021] S6: judging whether a new real-time motor speed signal is collected by a speed sensor in the interventional heart pump, if yes, entering S4; if no, entering S7;

[0022] S7: judging whether the physiological monitoring device receives a new physiological monitoring signal, if yes, returning to S2, if no, entering S1.

[0023] Compared with the prior art, the present application has the following advantages:

[0024] In the present application, the control algorithm of the implantable heart pump includes a patient circulation system model and an implantable heart pump model, realizing automatic adjustment and real-time adjustment, and avoiding the situation that setting a constant rotating speed cannot adapt to various physiological conditions.

[0025] The control method can consider the condition of each patient through the patient circulation system model, and can set different control strategies and parameters according to the patient condition and treatment needs, realizing personalized treatment.

[0026] The control method utilizes the implantable heart pump model, including a blood fluid model and a motor electromagnetic model, improving the control precision.

[0027] The present application stores the obtained real-time data in the controller, and when the controller outputs a signal, the control algorithm takes the historical data as a reference quantity, so that the calculated data is more accurate and more suitable for the actual patient needs.

[0028] In the present application, the set signal can be modified at any time, or can be set for a long time, adapting to various acute or chronic disease conditions, and being beneficial to adjustment according to the actual needs of the patient, and having a wider adaptation range.

[0029] The controller of the present application realizes the integration of the implantable heart pump and the physiological monitoring device, improving the convenience.

[0030] The advantages of the additional aspects of the present application will be partially given in the following description, or be understood through the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0031] The drawings constituting a part of the specification of the present application are used to provide further understanding of the present application, and the schematic embodiments of the present application and the description thereof are used to explain the present application, and do not constitute an improper limitation on the present application.

[0032] Figure 1 The implantable heart pump control system of the first embodiment;

[0033] Figure 2 The implantable heart pump control block diagram of the first embodiment. DETAILED DESCRIPTION

[0034] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0035] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Furthermore, it should be understood that the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0036] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0037] All data acquisition in this embodiment is carried out in accordance with laws and regulations and with user consent, and the data is used legally.

[0038] Example 1

[0039] This embodiment provides a control system for an interventional cardiac pump;

[0040] like Figure 1 As shown, a control system for an interventional heart pump includes: an interventional heart pump;

[0041] The interventional cardiac pump is connected to the controller via a motor driver;

[0042] The controller is connected to the physiological monitoring equipment;

[0043] The controller is also connected to a computer terminal;

[0044] The controller is configured to: acquire physiological signals monitored by physiological monitoring equipment; obtain motor control signals based on the physiological signals, the motor speed signal of the interventional cardiac pump, and a setting signal; send the motor control signals to the motor driver; obtain the rotor speed based on the motor control signals; and control the rotor rotation speed of the interventional cardiac pump based on the rotor speed.

[0045] Furthermore, the physiological monitoring device includes a blood pressure monitor and a blood flow meter.

[0046] Furthermore, the model of the interventional heart pump, for example: Impella.

[0047] Further, the installation position of the implantable heart pump is installed in the ventricle or installed in the aorta.

[0048] Further, the motor speed signal of the implantable heart pump is collected by a sensor in the heart pump motor, and the sensor is a Hall sensor.

[0049] As shown in Figure 1 The control system includes a data acquisition system, a physiological monitoring device and a controller.

[0050] The data acquisition system mainly collects signals of different devices and human input signals, and performs signal processing and inputs into the controller. The input signals mainly include motor speed signals, patient physiological signals and human set signals.

[0051] The motor speed signal is provided by a sensor in the heart pump motor, which is generally a Hall sensor. By detecting the rotor position, the real-time speed signal of the heart pump is obtained.

[0052] The patient physiological signal is provided by the physiological monitoring device, which generally includes blood pressure, blood flow and pulse signals.

[0053] The human set signal is a set signal input according to the heart pump user condition and treatment scheme, which generally includes blood pressure, blood volume, etc.

[0054] The set signal can be input by the controller panel or by the computer connected to the controller.

[0055] The data acquisition system includes various sensors and signal processing systems.

[0056] Various sensors are located at different positions of the implantable heart pump, including the speed sensor inside the pump body and various monitoring sensors in the physiological monitoring device.

[0057] The signal processing system is composed of multiple signal processors. For each input signal, isolation and noise reduction are performed to improve the accuracy and reliability of the input signal and provide more accurate input signals for the main control chip.

[0058] The physiological monitoring device is mainly used to monitor the real-time physiological signals of the patient and input into the controller through the data line. The physiological signals include blood pressure, blood flow and pulse frequency.

[0059] Blood pressure and pulse are measured by a sphygmomanometer, which is portable and outputs blood pressure signals as electrical signals.

[0060] Blood flow is measured by a flowmeter, and the main signal is the left ventricular blood output, which can be calculated by measuring the blood flow of a certain blood vessel. The output signal is an electrical signal.

[0061] The physiological monitoring device can be integrated with the interventional heart pump, or can be a separate device.

[0062] Embodiment two

[0063] The embodiment provides a control method of an interventional heart pump;

[0064] The control method of the interventional heart pump comprises the following steps:

[0065] S201: acquiring a human setting signal; the human setting signal comprises a set blood pressure, a set blood flow and a set pulsation frequency;

[0066] S202: when first executed, obtaining a required blood flow of a patient according to the human setting signal and a preset patient blood circulation system model;

[0067] When not executed for the first time, obtaining the required blood flow of the patient according to a signal collected by a physiological monitoring device and the preset patient blood circulation system model;

[0068] S203: obtaining a blood flow, an outlet end blood pressure and a blood flow field distribution of the interventional heart pump according to the required blood flow of the patient and a preset blood fluid model;

[0069] S204: obtaining a required motor speed signal according to the blood flow, the outlet end blood pressure, the blood flow field distribution of the interventional heart pump, a real-time motor speed and a preset electromagnetic coupling model; when S204 is executed for the first time, the real-time motor speed is zero;

[0070] S205: a motor driver compares the real-time motor speed with the required motor speed signal to generate a control signal, the control signal is input into a motor winding of the interventional heart pump to generate an electromagnetic torque, the motor winding drives a rotor to rotate, blood is driven to move through an impeller, and thus auxiliary circulation of blood is realized;

[0071] S206: judging whether a new real-time motor speed signal is collected by a speed sensor in the interventional heart pump, if yes, proceeding to S204; if no, proceeding to S207;

[0072] S207: judging whether a new physiological monitoring signal is received by the physiological monitoring device, if yes, returning to S202; if no, proceeding to S201.

[0073] Further, the patient blood circulation system model refers to:

[0074] S2021: constructing a convolutional neural network;

[0075] S2022: constructing a training set; the training set is a set blood pressure, a set blood flow and a set pulsation frequency of a known required blood flow of a patient.

[0076] S2023: input the training set into the convolutional neural network for training, and obtain the trained convolutional neural network as the blood circulation system model of the patient when the training is completed.

[0077] Further, the preset blood fluid model includes the following construction process.

[0078] S203a1: a blood fluid model is established by using a finite element method; and an interventional heart pump geometric model is established based on pump body size, impeller shape, and interface shape.

[0079] S203a2: material and physical parameters of each part in the interventional heart pump geometric model are set; the material and physical parameters include pump body material, blood viscosity, and blood specific gravity.

[0080] S203a3: boundary conditions (flow rate or pressure of fluid) of the pump body and the inlet and outlet end are set.

[0081] S203a4: a mesh is divided to solve equations for each mesh.

[0082] S203a5: a fluid Bernoulli equation is constructed based on blood density, viscosity, and compression ratio parameters; and the fluid Bernoulli equation is solved.

[0083] S203a6: results are obtained and displayed.

[0084] S203a7: a blood fluid model is obtained.

[0085] Further, the preset blood fluid model includes the following application steps.

[0086] S203b1: a blood fluid model is established by using a finite element method.

[0087] S203b2: boundary conditions (pressure or flow rate range of blood) of the pump body and the inlet and outlet end are set.

[0088] S203b3: a fluid Bernoulli equation is constructed based on blood density, viscosity, and compression ratio parameters.

[0089] S203b4: the fluid Bernoulli equation is solved based on the boundary conditions; and blood flow and blood flow field in the pump body are calculated.

[0090] S203b5: blood density, viscosity, and compression ratio parameters are input according to the patient condition; blood flow fields at different rotating speeds are simulated and calculated by using the finite element method; blood flow field distribution, blood flow, and outlet end blood pressure at different rotating speeds are obtained; and resistance torque of blood on the impeller is also obtained.

[0091] According to the impeller shape, size, flow passage size, the blood flow field during the impeller rotation is simulated.

[0092] The blood flow model sets the boundary conditions of the blood flow field according to the impeller rotating speed and the blood pressure at the inlet and outlet, and calculates the blood flow and the blood flow field in the pump body according to the fluid Bernoulli equation.

[0093] Further, the preset electromagnetic coupling model includes the following construction process:

[0094] S204a1: An electromagnetic coupling model is established by using a finite element method, and an interventional heart pump motor geometric model is established according to the geometric size of the motor stator and rotor, the winding mode, the number of turns of the winding, the stator-rotor gap; the interventional heart pump motor geometric model includes a motor stator and a motor rotor, and the motor stator includes a winding and an iron core;

[0095] S204a2: The materials and physical parameters of each part in the model are set, including the magnetic permeability and electrical conductivity of the stator and rotor materials;

[0096] S204a3: The boundary conditions of the finite element are set, including the magnetic field value and the electric field value at the boundary;

[0097] S204a4: The mesh is divided so that the equation can be solved for each mesh;

[0098] S204a5: The Maxwell equation in each mesh area is solved according to the boundary conditions and the mesh division results;

[0099] S204a6: The results are obtained and displayed to obtain the preset electromagnetic coupling model.

[0100] Further, the application steps of the preset electromagnetic coupling model include:

[0101] S204b1: An electromagnetic coupling model is established by using a finite element method, and first the driving signal is converted into a current signal, which is input into the motor driving coil, and the electromagnetic field generated by the current in the motor is calculated according to the Maxwell equation, and then the electromagnetic torque received by the rotor is calculated;

[0102] S204b2: According to the calculated impeller resistance torque and electromagnetic torque, the kinematics equation of the rotor is established and solved to obtain the change of the rotor speed with time.

[0103] The preset electromagnetic coupling model is established according to the interventional heart pump motor, and is used for simulating and calculating the actual speed of the motor with time under different driving signals.

[0104] The electromagnetic coupling model is used for simulating the rotor motion of the interventional heart pump.

[0105] According to the signal input by the motor driver, the electromagnetic torque on the rotor is calculated, the resistance torque on the rotor is calculated according to the blood fluid condition, and the rotor motion equation is solved according to the joint action of the electromagnetic torque and the resistance torque, so that the real-time rotating speed of the rotor is obtained.

[0106]

[0107] T e is the electromagnetic torque, T b is the blood resistance torque, J is the rotor moment of inertia, and ω is the rotor angular velocity.

[0108] The blood fluid model and the electromagnetic coupling model jointly constitute the interventional heart pump model.

[0109] The controller mainly includes a power module, a main control chip and an auxiliary circuit. The power module provides power for the whole controller. The main control chip is the control core, which stores the control algorithm internally, performs operation according to the input signal, obtains the output signal, and controls the operation of the interventional heart pump. The auxiliary circuit is composed of a series of electronic components and provides support for the normal operation of the main control chip.

[0110] The control algorithm is the core of the controller. In the present application, the control algorithm is mainly based on the coupling model of the patient's blood circulation system and the interventional heart pump. First, the patient's blood circulation system and the interventional heart pump are modeled respectively. The patient's blood circulation system model includes the left and right ventricles, the left and right atria, the systemic circulation and the pulmonary circulation, and the interventional heart pump model includes the blood fluid model and the electromagnetic coupling model.

[0111] The interventional heart pump is coupled with the patient's blood circulation system according to its installation position and participates in the patient's blood circulation. The blood pumping capacity of the interventional heart pump is superimposed on the blood pumping capacity of the original heart, forming the total blood pumping capacity. According to the installation position of the interventional heart pump, it can be divided into parallel type and series type.

[0112] The specific control algorithm block diagram is shown in Figure 2 The set signal is input into the controller, including blood pressure, blood flow and pulse frequency. The patient's blood circulation system model determines the model parameters according to the set value and the patient's information, simulates the blood circulation state under heart failure condition. The controller compares the blood flow under different heart failure conditions with the normal physiological needs of the patient, calculates the required flow of the interventional heart pump, inputs the required flow into the interventional heart pump model, obtains the required rotating speed signal of the motor according to the blood fluid model and the electromagnetic coupling model, and inputs the rotating speed signal into the motor driver to form the control signal, which is input into the motor winding of the interventional heart pump to generate electromagnetic torque, drive the rotor to rotate, drive the blood movement through the impeller, and thus realize the auxiliary circulation function.

[0113] The motor rotating speed signal is collected by an internal rotating speed sensor of the interventional heart pump, and is input into the controller as an input signal through signal processing, compared with the set rotating speed signal output by the controller, to realize rotating speed closed-loop control. The rotating speed closed-loop control algorithm can be traditional PID control, or more advanced fuzzy PID, field-oriented control, etc.

[0114] When the interventional heart pump is working, the signals collected by the physiological monitoring device, including blood pressure, blood flow and pulse frequency, are returned to the input end of the controller in real time, compared with the input signals, to be used for closed-loop control of blood pressure, blood flow and pulse frequency.

[0115] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A control system for an interventional heart pump, characterized in that The application relates to a control system of an interventional heart pump. The interventional heart pump is connected with a controller through a motor driver; The setting signal can be input by a controller panel or a computer connected with the controller; The controller is connected with a physiological monitoring device; The controller is also connected with a computer terminal; The controller is configured to acquire a physiological signal monitored by the physiological monitoring device, obtain a motor control signal according to the physiological signal, a motor rotating speed signal of the interventional heart pump and a setting signal, and send the motor control signal to the motor driver, so that the motor driver obtains a rotor rotating speed according to the motor control signal and controls a rotor rotating speed of the interventional heart pump according to the rotor rotating speed. The controller has the following regulation process: S1: acquiring a human setting signal; The human setting signal includes setting blood pressure, setting blood flow and setting pulse frequency; S2: when executed for the first time, a preset patient blood circulation system model is adopted to obtain a required blood flow of the patient according to the human setting signal; When executed for the second time, a preset patient blood circulation system model is adopted to obtain a required blood flow of the patient according to a signal collected by the physiological monitoring device; S3: a preset blood fluid model is adopted according to the required blood flow of the patient; A blood fluid model is established by using a finite element method to obtain the blood flow, outlet end blood pressure and blood flow field distribution of the interventional heart pump; S4: a preset electromagnetic coupling model is adopted according to the blood flow, outlet end blood pressure, blood flow field distribution, motor real-time rotating speed and preset electromagnetic coupling model of the interventional heart pump; The electromagnetic coupling model is established by using a finite element method to obtain a required motor rotating speed signal; when S4 is executed for the first time, the motor real-time rotating speed is zero; S5: the motor driver compares the motor real-time rotating speed with the required motor rotating speed signal to generate a control signal, the control signal is input into the motor winding of the interventional heart pump to generate an electromagnetic torque, the rotor is driven to rotate, the blood is driven to move through the impeller, and the auxiliary circulation of the blood is realized; S6: whether the rotating speed sensor in the interventional heart pump collects a new motor real-time rotating speed signal is judged, if yes, S4 is entered; if no, S7 is entered; S7: whether the physiological monitoring device receives a new physiological monitoring signal is judged, if yes, S2 is returned; if no, S1 is entered; The patient blood circulation system model is that: A convolutional neural network is constructed; A training set is constructed; the training set is the setting blood pressure, setting blood flow and setting pulse frequency of the known required blood flow of the patient; The training set is input into the convolutional neural network for training, and when the training is completed, the trained convolutional neural network is the patient blood circulation system model.

2. The control system of the interventional heart pump according to claim 1, wherein the physiological monitoring device includes a sphygmomanometer and a blood flow meter.

3. The control system of the interventional heart pump according to claim 1, wherein the installation position of the interventional heart pump is that the interventional heart pump is installed in a ventricular aorta or in a ventricle.

4. The control system of the interventional heart pump according to claim 1, wherein ​ ​ ​ The motor rotating speed signal of the intervention heart pump is collected by a sensor in the heart pump motor, and the sensor is a Hall sensor.

5. A control system for an intercardiopulmonary pump according to claim 1, characterized in that The preset blood fluid model has a construction process including: An intervention heart pump geometric model is established based on pump body size, impeller shape, and interface shape; Material and physical parameters of each part in the intervention heart pump geometric model are set, and the material and physical parameters include pump body material, blood viscosity, and blood specific gravity; Boundary conditions of the pump body and the inlet and outlet end are set, and the boundary conditions include fluid flow rate or pressure; Meshes are divided so that equations are solved for each mesh; A fluid Bernoulli equation is constructed based on blood density, viscosity, and compression ratio parameters, and the fluid Bernoulli equation is solved; Results are obtained and displayed; The blood fluid model is obtained.

6. A control system for an intercardiopulmonary pump according to claim 1, characterized in that The preset electromagnetic coupling model has a construction process including: An intervention heart pump motor geometric model is established based on motor stator and rotor geometric size, winding mode, winding number of turns, and stator-rotor gap, and the intervention heart pump motor geometric model includes a motor stator and a motor rotor, and the motor stator includes windings and an iron core; Material and physical parameters of each part in the model are set, and the material and physical parameters include stator and rotor material magnetic permeability and electrical conductivity; Boundary conditions of the finite element are set, and the boundary conditions include boundary magnetic field values and electric field values; Meshes are divided so that equations are solved for each mesh; Maxwell equations in each mesh region are solved based on the boundary conditions and the mesh division results; Results are obtained and displayed, and the preset electromagnetic coupling model is obtained.

7. A control system for an intercardiotomy pump as defined in claim 1, characterized in that The preset blood fluid model has an application process including: A blood fluid model is established by using a finite element method; Boundary conditions of the pump body and the inlet and outlet end are set, and the boundary conditions include blood pressure or flow rate domains; A fluid Bernoulli equation is constructed based on blood density, viscosity, and compression ratio parameters; The fluid Bernoulli equation is solved based on the boundary conditions, and blood flow and blood flow field in the pump body are calculated; Blood density, viscosity, and compression ratio parameters are input according to patient conditions, blood flow fields at different rotating speeds are simulated and calculated by using the finite element method, blood flow field distribution, blood flow, and outlet end blood pressure at different rotating speeds are obtained, and blood resistance torque on the impeller is also obtained.

8. A control system for an intercardiotomy pump as defined in claim 1, characterized in that The preset electromagnetic coupling model has an application process including: An electromagnetic coupling model is established by using a finite element method, a driving signal is first converted into a current signal, the current signal is input into a motor driving coil, an electromagnetic field generated by the current in the motor is calculated according to Maxwell equations, and then electromagnetic torque received by the rotor is calculated; Based on the calculated impeller resistance torque and electromagnetic torque, a kinematics equation of the rotor is established, and the kinematics equation is solved, so that the rotor speed change with time is obtained.

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