Intramedullary lengthening system extension length control device and method

Abstract

The invention relates to the technical field of electromagnetic driving, in particular to an intramedullary extension system extension length control device and method, and the device comprises a data collection module which is used for collecting current data and voltage data of a three-phase winding of an electromagnetic driver; the back electromotive force calculation module is used for calculating a back electromotive force signal of each phase winding; the phase calculation module is used for calculating the phase of the permanent magnet rotor; the vector control module is used for building a position closed-loop control system for the electromagnetic driver so as to perform position closed-loop control on the permanent magnet rotor through the position closed-loop control system; and the extension length control module is used for performing closed-loop control on the extension length based on a preset transmission mechanism in the intramedullary extension nail. Therefore, the problem that an existing intramedullary lengthening system cannot achieve precise control over the elongation amount is solved, closed-loop control over the position of the permanent magnet rotor is achieved, and then precise control over the extension length of the intramedullary lengthening system is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electromagnetic driving, and in particular to a length control device and method for an intramedullary lengthening system. BACKGROUND

[0002] Limb length discrepancy and pathological short stature are common diseases in clinical orthopedics, which significantly affect the quality of life of patients. The traditional treatment method mainly uses the Ilizarov circular external fixation support, which connects the support and the bone through Kirschner wire by percutaneous connection, and realizes bone lengthening by external traction. However, due to the long healing period of bone lengthening, this external traction treatment scheme often accompanies side effects such as needle tract infection and nerve compression, which brings additional pain and treatment risks to patients.

[0003] In related technologies, the electromagnetic driving intramedullary lengthening system is gradually attracting attention as a new treatment method. The system generates a rotating magnetic field through an external electromagnetic driver to drive the permanent magnet rotor inside the intramedullary lengthening nail to produce a rotating motion, and realizes axial lengthening through the screw transmission mechanism inside the intramedullary lengthening nail. However, the current electromagnetic driving intramedullary lengthening system only uses an open-loop control method driven by an external rotating magnetic field to drive an internal permanent magnet, lacks precise detection of the position and speed of the permanent magnet rotor, and thus cannot achieve precise control of the extension amount of the intramedullary lengthening system. Since bone lengthening requires precise control of the extension amount (for example, 1 mm per day and 0.25 mm per time), the intramedullary lengthening system needs to provide very high position control accuracy, and such an open-loop control method cannot achieve precise control of the extension amount, which limits the treatment effect and needs to be solved urgently. SUMMARY

[0004] The present application provides a length control device and method for an intramedullary lengthening system to solve the problem that the existing intramedullary lengthening system cannot achieve precise control of the extension amount, and realizes closed-loop control of the position of the permanent magnet rotor and precise control of the extension length of the intramedullary lengthening system.

[0005] The first aspect of the present application provides a length control device for an intramedullary lengthening system, comprising:

[0006] A data acquisition module is configured to acquire current data and voltage data on a three-phase winding of an electromagnetic driver;

[0007] A back electromotive force calculation module is configured to calculate a back electromotive force signal of each phase winding according to a voltage balance equation of each phase winding of the electromagnetic driver, current data of each phase winding, voltage data of each phase winding, and resistance and inductance parameters of the electromagnetic driver;

[0008] A phase calculation module is configured to calculate a phase of a permanent magnet rotor according to the back electromotive force signal of each phase winding;

[0009] The vector control module is used to build a position closed-loop control system for the electromagnetic actuator based on the phase of the permanent magnet rotor, so as to perform position closed-loop control on the permanent magnet rotor through the position closed-loop control system.

[0010] The extension length control module is used to perform closed-loop control of the extension length based on the preset internal transmission mechanism of the intramedullary extension nail after the position closed-loop control system performs position closed-loop control of the permanent magnet rotor.

[0011] Optionally, in some embodiments, the data acquisition module includes:

[0012] A current detection component is used to collect current data on the three-phase windings of the electromagnetic driver.

[0013] A voltage detection component is used to collect voltage data on the three-phase windings of the electromagnetic driver.

[0014] The sampling frequency setting unit is used to dynamically adjust the sampling frequency according to the control accuracy requirements.

[0015] Optionally, in some embodiments, the phase calculation module includes:

[0016] The projection unit is used to orthogonally project the back electromotive force signal of each phase winding to obtain the components of the back electromotive force signal of each phase winding in the orthogonal coordinate system.

[0017] The calculation unit is used to perform arctangent calculation on the component of the back electromotive force signal of each phase winding in the orthogonal coordinate system to obtain the phase of the permanent magnet rotor.

[0018] Optionally, in some embodiments, the vector control module further includes:

[0019] A current loop control circuit is used to perform coordinate transformation based on the phase of the permanent magnet rotor and to perform decoupled calculations of the phase and current amplitude of the permanent magnet rotor.

[0020] A speed loop control circuit is used for closed-loop speed control of the permanent magnet rotor;

[0021] A position loop control circuit is used to perform closed-loop position control on the permanent magnet rotor.

[0022] Optionally, in some embodiments, the back electromotive force calculation module further includes:

[0023] The filtering unit is used to filter the back electromotive force signal.

[0024] Optionally, in some embodiments, the phase of the back electromotive force signal is orthogonal to the phase of the permanent magnet rotor.

[0025] Optionally, in some embodiments, the electromagnetic actuator is made of three-phase copper wire wound on a silicon steel core.

[0026] According to the intramedullary length extension system extension length control device of this application embodiment, the back electromotive force signal of each phase winding is calculated based on the voltage balance equation of each phase winding of the electromagnetic actuator, the current data of each phase winding, the voltage data of each phase winding, and the resistance and inductance parameters of the electromagnetic actuator. The phase of the permanent magnet rotor is then calculated based on the back electromotive force signal of each phase winding. The permanent magnet rotor is subjected to closed-loop position control through a position closed-loop control system, and the extension length is controlled in a closed-loop manner based on a preset internal transmission mechanism of the intramedullary length extension nail. This solves the problem that existing intramedullary length extension systems cannot achieve precise control of the extension amount, realizes closed-loop position control of the permanent magnet rotor, and thus achieves precise control of the extension length of the intramedullary length extension system.

[0027] A second aspect of this application provides a method for controlling the extension length of an intramedullary lengthening system, employing the aforementioned intramedullary lengthening system extension length control device, wherein the method includes the following steps:

[0028] The data acquisition module is used to acquire current and voltage data on the three-phase windings of the electromagnetic driver.

[0029] The back electromotive force calculation module calculates the back electromotive force signal of each phase winding based on the voltage balance equation of each phase winding of the electromagnetic driver, the current data of each phase winding, the voltage data of each phase winding, and the resistance and inductance parameters of the electromagnetic driver.

[0030] The phase of the permanent magnet rotor is obtained by using the phase calculation module to calculate based on the back electromotive force signal of each phase winding;

[0031] The vector control module is used to build a position closed-loop control system for the electromagnetic actuator based on the phase of the permanent magnet rotor, so as to perform position closed-loop control of the permanent magnet rotor through the position closed-loop control system.

[0032] After the permanent magnet rotor is controlled in a closed-loop position by the position closed-loop control system, the extension length is controlled in a closed-loop manner based on the preset internal transmission mechanism of the intramedullary extension nail using the extension length control module.

[0033] According to one embodiment of this application, the step of using the phase calculation module to calculate the phase of the permanent magnet rotor based on the back electromotive force signal of each phase winding includes:

[0034] The back electromotive force signal of each phase winding is orthogonally projected using a projection unit to obtain the components of the back electromotive force signal of each phase winding in an orthogonal coordinate system.

[0035] The phase of the permanent magnet rotor is obtained by calculating the arctangent of the back electromotive force signal of each phase winding in the orthogonal coordinate system using a computing unit.

[0036] According to one embodiment of this application, the position closed-loop control of the permanent magnet rotor through the position closed-loop control system includes:

[0037] Using a current loop control circuit, coordinate transformation is performed based on the phase of the permanent magnet rotor, and decoupling calculations are performed on the phase and current amplitude of the permanent magnet rotor.

[0038] The rotational speed of the permanent magnet rotor is controlled in a closed-loop manner using a rotational speed loop control circuit.

[0039] The permanent magnet rotor is subjected to closed-loop position control using a position loop control circuit.

[0040] According to the extension length control method of the intramedullary extension system in this application, the back electromotive force signal of each phase winding is calculated based on the voltage balance equation of each phase winding of the electromagnetic actuator, the current data of each phase winding, the voltage data of each phase winding, and the resistance and inductance parameters of the electromagnetic actuator. The phase of the permanent magnet rotor is then calculated based on the back electromotive force signal of each phase winding. The permanent magnet rotor is then subjected to closed-loop position control through a position closed-loop control system, and the extension length is controlled in a closed-loop manner based on a preset internal transmission mechanism of the intramedullary extension nail. This solves the problem that existing intramedullary extension systems cannot achieve precise control of the extension amount, realizes closed-loop position control of the permanent magnet rotor, and thus achieves precise control of the extension length of the intramedullary extension system.

[0041] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the intramedullary length extension control method as described in the above embodiments.

[0042] A fourth aspect of this application provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement the intramedullary length extension system extension length control method as described in the above embodiments.

[0043] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0044] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0045] Figure 1 This is a schematic diagram of the structure of an electromagnetically driven intramedullary lengthening system according to an embodiment of this application;

[0046] Figure 2 This is a schematic diagram of the structure of an electromagnetic drive module for a controlled object according to an embodiment of this application;

[0047] Figure 3 This is a block diagram of an intramedullary lengthening system extension length control device according to an embodiment of this application;

[0048] Figure 4 This is a simplified circuit model schematic diagram of an electromagnetic driver according to an embodiment of this application;

[0049] Figure 5 This is a block diagram of the magnetic field orientation control of an electromagnetic drive module according to an embodiment of this application;

[0050] Figure 6 This is a flowchart of a method for controlling the extension length of an intramedullary lengthening system according to an embodiment of this application;

[0051] Figure 7 This is a flowchart of an intramedullary lengthening system extension length control method according to an embodiment of this application. Detailed Implementation

[0052] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0053] The following description, with reference to the accompanying drawings, describes an intramedullary length extension system extension length control device and method according to embodiments of this application.

[0054] Before introducing the intramedullary length extension system extension length control device of the embodiments of this application, we will first introduce the intramedullary length extension system and the electromagnetic drive module of the controlled object used in the intramedullary length extension system extension length control device provided in the embodiments of this application.

[0055] Specifically, such as Figure 1 As shown, the intramedullary lengthening system includes an electromagnetic actuator 1 that provides a rotating magnetic field and an intramedullary lengthening nail 2 with telescoping function. The intramedullary lengthening nail 2 can be lengthened and shortened under the action of the rotating magnetic field generated by the electromagnetic actuator 1.

[0056] Furthermore, such as Figure 2 As shown, the electromagnetic drive module of the controlled object includes an electromagnetic actuator 1 and a permanent magnet rotor 3, wherein the permanent magnet rotor 3 is an internal component of the intramedullary lengthening nail 2. The electromagnetic actuator 1 drives the permanent magnet rotor 3 by generating a rotating magnetic field, thereby driving the intramedullary lengthening nail 2 to achieve elongation or shortening.

[0057] The following describes the extension length control device for the intramedullary lengthening system proposed in this application.

[0058] Specifically, Figure 3 This is a block diagram of an intramedullary lengthening system extension length control device provided in an embodiment of this application.

[0059] like Figure 3 As shown, the intramedullary length extension system extension length control device 10 includes: a data acquisition module 100, a back electromotive force calculation module 200, a phase calculation module 300, a vector control module 400, and an extension length control module 500.

[0060] The system includes: a data acquisition module 100 for acquiring current and voltage data from the three-phase windings of the electromagnetic actuator; a back electromotive force calculation module 200 for calculating the back electromotive force signal of each phase winding based on the voltage balance equation, current data, voltage data, and resistance and inductance parameters of each phase winding; a phase calculation module 300 for calculating the phase of the permanent magnet rotor based on the back electromotive force signal of each phase winding; a vector control module 400 for establishing a position closed-loop control system for the electromagnetic actuator based on the phase of the permanent magnet rotor, thereby enabling position closed-loop control of the permanent magnet rotor; and an extension length control module 500 for performing closed-loop control of the extension length based on a preset internal transmission mechanism of the intramedullary extension nail after position closed-loop control of the permanent magnet rotor via the position closed-loop control system.

[0061] Specifically, the data acquisition module 100 first acquires data. A sampling frequency is set, and the data acquisition module 100 acquires current and voltage data from the three-phase windings of the electromagnetic driver 1.

[0062] Secondly, the back electromotive force (EMF) is calculated using the back EMF calculation module 200. Based on the voltage balance equation of each phase winding of the electromagnetic driver 1, and according to the collected current and voltage data and the resistance and inductance parameters of the electromagnetic driver 1 itself, the back EMF signal of the three-phase winding of the electromagnetic driver is calculated.

[0063] Furthermore, phase calculation is performed using the phase calculation module 300. The back electromotive forces ea, eb, and ec are 120° out of phase. By orthogonally projecting these three back electromotive forces into an orthogonal coordinate system, their components in the orthogonal coordinate system are obtained, and then the arctangent is calculated to obtain the phase of the permanent magnet rotor.

[0064] Furthermore, the vector control module 400 combines the phase of the permanent magnet rotor to build a position closed-loop control system for the electromagnetic actuator 2, thereby realizing the position closed-loop control of the permanent magnet rotor.

[0065] Finally, after the permanent magnet rotor 3 achieves closed-loop position control, the extension length control module 500 can achieve closed-loop control of the extension length through the internal transmission mechanism of the intramedullary extension nail.

[0066] Optionally, in some embodiments, the data acquisition module 100 includes: a current detection component for acquiring current data on the three-phase windings of the electromagnetic driver; a voltage detection component for acquiring voltage data on the three-phase windings of the electromagnetic driver; and a sampling frequency setting unit for dynamically adjusting the sampling frequency according to control accuracy requirements.

[0067] In some embodiments, the electromagnetic actuator is made of three-phase copper wire wound on a silicon steel core, which can be simplified as follows: Figure 4 As shown, the impedance of each three-phase winding can be considered as consisting of three parts: resistive impedance, inductive impedance, and back electromotive force.

[0068] Optionally, the current detection component can be a current sensor, and the voltage detection component can be a voltage sensor; no specific limitation is made here.

[0069] Specifically, the sampling frequency is set by the sampling frequency setting unit, the current data on the three-phase winding of the electromagnetic driver 1 is collected by the current sensor, and the voltage data on the three-phase winding of the electromagnetic driver 1 is collected by the voltage sensor.

[0070] Optionally, in some embodiments, the back EMF calculation module 200 further includes a filtering unit for filtering the back EMF signal.

[0071] In some embodiments, the phase of the back electromotive force signal is orthogonal to the phase of the permanent magnet rotor.

[0072] Specifically, when the permanent magnet rotor 3 rotates, a back electromotive force (EMF) is generated on the windings of the electromagnetic driver 1. The phase of this back EMF is orthogonal to the phase of the permanent magnet rotor 3; therefore, the back EMF contains the position information of the permanent magnet rotor 3. A voltage balance equation is established for each phase winding of the electromagnetic driver 2, meaning the bus voltage of each phase winding consists of the resistance voltage drop, the inductance voltage drop, and the back EMF. Therefore, based on the collected current and voltage data from the three-phase windings of the electromagnetic driver, combined with the resistance and inductance parameters of the electromagnetic driver 1 itself, the back EMF signal can be obtained. The formula for calculating the back EMF signal is:

[0073]

[0074] Among them, e a Let U be the opposite electromotive force. a Let R be the voltage of phase a. a Let i be the resistance of phase a. a Let L be the phase current. a For phase a inductance, e b For the opposite electromotive force of b, U b For phase b voltage, R b For phase b resistance, i b Let L be the phase b current. b For phase inductance, e c For c, the opposite electromotive force, U c For phase c voltage, R c For phase c resistance, i c For c-phase current, L c This is the c-phase inductance.

[0075] It should be noted that the above-described direct calculation of back electromotive force through the voltage balance equation is a preferred embodiment of this application. In other embodiments of this application, the back electromotive force can also be observed by means of a sliding membrane observer (SMO) through the phase current, phase voltage and electrical parameters of the electromagnetic actuator. No specific limitation is made here.

[0076] Optionally, in some embodiments, the phase calculation module 300 includes: a projection unit for orthogonally projecting the back EMF signal of each phase winding to obtain the component of the back EMF signal of each phase winding in the orthogonal coordinate system; and a calculation unit for performing arctangent calculation on the component of the back EMF signal of each phase winding in the orthogonal coordinate system to obtain the phase of the permanent magnet rotor.

[0077] Specifically, in an electromagnetically driven intramedullary extension system, when the permanent magnet rotor rotates, a back electromotive force (EMF) is induced in the three-phase windings of the stator. In order to extract rotor position information from the three-phase time-varying signal, the three-phase back EMF needs to be converted to an orthogonal coordinate system. By orthogonally projecting the back EMF signal of each phase winding, the component of the back EMF signal of each phase winding in the orthogonal coordinate system can be obtained. By calculating the arctangent of the component of the back EMF signal of each phase winding in the orthogonal coordinate system, the phase of the permanent magnet rotor can be obtained.

[0078] It should be noted that for high signal-to-noise ratio back EMF signals, direct arctangent calculation is preferred. Furthermore, in other embodiments of this application, for example in low signal-to-noise ratio environments, if the waveform of the back EMF is not smooth, it can be integrated first, and then a high-pass filter can be used to filter out drift signals before calculating using the arctangent function to obtain the phase of the permanent magnet rotor 3. Additionally, in other embodiments of this application, a phase-locked loop (PLL) can also be used to achieve phase discrimination of the permanent magnet rotor 3 through the back EMF signal.

[0079] Optionally, in some embodiments, the vector control module 400 further includes: a current loop control circuit for performing coordinate transformation based on the phase of the permanent magnet rotor and performing decoupling calculation of the phase and current amplitude of the permanent magnet rotor; a speed loop control circuit for performing closed-loop speed control of the permanent magnet rotor; and a position loop control circuit for performing closed-loop position control of the permanent magnet rotor.

[0080] Specifically, after obtaining the phase of the permanent magnet rotor 3 based on the back electromotive force, this phase can be used as the phase reference for the current loop coordinate transformation of the field-oriented control, thereby realizing the field-oriented speed closed-loop control of the electromagnetic drive module. The control block diagram is as follows: Figure 5 As shown. The rotational speed of the permanent magnet rotor 3 can be obtained by calculating the phase derivative and filtering out high-frequency noise using a low-pass filter. The field-oriented control includes three control closed-loop loops: a current loop, a speed loop, and a position loop. The current loop uses the phase of the permanent magnet rotor 3 for coordinate transformation, achieving decoupled calculation of the phase and current amplitude of the permanent magnet rotor 3. A PI controller can achieve good current tracking. The speed loop is located outside the current loop and uses a PI controller to track the target speed. The speed closed-loop control quantity is obtained from the phase integral calculated by the back electromotive force, thus achieving closed-loop speed control of the permanent magnet rotor 3. The position loop is located outside the speed loop and is the outermost control closed loop of the entire control system. It tracks the target position using a PI controller, and the closed-loop controlled quantity is obtained by the sensorless rotor position identification module.

[0081] Therefore, this application calculates the back electromotive force generated on the electromagnetic actuator by the rotation of the permanent magnet rotor, uses the back electromotive force to calculate the phase of the permanent magnet rotor, and then builds a magnetic field orientation control system for the electromagnetic actuator-permanent magnet rotor to realize closed-loop control of the permanent magnet rotor position, thereby realizing control of the extension length of the intramedullary extension system.

[0082] According to the intramedullary length extension system extension length control device of this application embodiment, the back electromotive force signal of each phase winding is calculated based on the voltage balance equation of each phase winding of the electromagnetic actuator, the current data of each phase winding, the voltage data of each phase winding, and the resistance and inductance parameters of the electromagnetic actuator. The phase of the permanent magnet rotor is then calculated based on the back electromotive force signal of each phase winding. The permanent magnet rotor is subjected to closed-loop position control through a position closed-loop control system, and the extension length is controlled in a closed-loop manner based on a preset internal transmission mechanism of the intramedullary length extension nail. This solves the problem that existing intramedullary length extension systems cannot achieve precise control of the extension amount, realizes closed-loop position control of the permanent magnet rotor, and thus achieves precise control of the extension length of the intramedullary length extension system.

[0083] Next, referring to the accompanying drawings, a method for controlling the extension length of an intramedullary lengthening system according to an embodiment of this application is described.

[0084] In this embodiment, the method for controlling the extension length of the intramedullary lengthening system employs the aforementioned device for controlling the extension length of the intramedullary lengthening system.

[0085] like Figure 6 As shown, the method for controlling the extension length of this intramedullary lengthening system includes the following steps:

[0086] In step S601, the current and voltage data on the three-phase windings of the electromagnetic driver are acquired using the data acquisition module.

[0087] In step S602, the back EMF calculation module calculates the back EMF signal of each phase winding based on the voltage balance equation of each phase winding of the electromagnetic driver, the current data of each phase winding, the voltage data of each phase winding, and the resistance and inductance parameters of the electromagnetic driver.

[0088] In step S603, the phase of the permanent magnet rotor is obtained by using the phase calculation module to calculate based on the back electromotive force signal of each phase winding.

[0089] In step S604, the vector control module is used to build a position closed-loop control system for the electromagnetic actuator based on the phase of the permanent magnet rotor, so as to perform position closed-loop control on the permanent magnet rotor through the position closed-loop control system.

[0090] In step S605, after the permanent magnet rotor is controlled in a closed-loop position by the position closed-loop control system, the extension length is controlled in a closed-loop manner based on the preset internal transmission mechanism of the intramedullary extension nail by the extension length control module.

[0091] Furthermore, in some embodiments, the phase calculation module calculates the phase of the permanent magnet rotor based on the back electromotive force signal of each phase winding, including: using a projection unit to orthogonally project the back electromotive force signal of each phase winding to obtain the component of the back electromotive force signal of each phase winding in the orthogonal coordinate system; and using a calculation unit to perform arctangent calculation on the component of the back electromotive force signal of each phase winding in the orthogonal coordinate system to obtain the phase of the permanent magnet rotor.

[0092] Furthermore, in some embodiments, the position closed-loop control of the permanent magnet rotor is performed by a position closed-loop control system, including: using a current loop control circuit to perform coordinate transformation based on the phase of the permanent magnet rotor, and to perform decoupling calculation of the phase and current amplitude of the permanent magnet rotor; using a speed loop control circuit to perform speed closed-loop control of the permanent magnet rotor; and using a position loop control circuit to perform position closed-loop control of the permanent magnet rotor.

[0093] To facilitate a clearer and more intuitive understanding by those skilled in the art of controlling the extension length of the intramedullary lengthening system proposed in this application, the following is combined with... Figure 7 Please provide a detailed explanation.

[0094] like Figure 7 As shown, the method for controlling the extension length of this intramedullary lengthening system includes the following steps:

[0095] Step 1: Data Acquisition: Set the sampling frequency and use current and voltage sensors to acquire current and voltage data on the three-phase windings of electromagnetic driver 1.

[0096] Step 2: Back EMF Calculation: Based on the voltage balance equation of each phase winding of electromagnetic driver 1, and according to the collected current and voltage data and the resistance and inductance parameters of electromagnetic driver 1 itself, the back EMF signal is calculated.

[0097] Step 3: Phase Calculation: The back electromotive forces ea, eb, and ec are 120° out of phase. By orthogonally projecting these three back electromotive forces into an orthogonal coordinate system, the components in the orthogonal coordinate system are obtained, and the arctangent is calculated to obtain the rotor phase.

[0098] Step 4: Vector control: Combine the phase of the permanent magnet rotor to build a position closed-loop control system for electromagnetic actuator 2, and realize rotor position closed-loop control.

[0099] Step 5: Extension length control: After the permanent magnet rotor 3 achieves closed-loop position control, the extension length can be closed-loop controlled through the internal transmission mechanism of the intramedullary extension nail.

[0100] It should be noted that the foregoing explanation of the embodiment of the intramedullary length extension system extension length control device also applies to the intramedullary length extension system extension length control method of this embodiment, and will not be repeated here.

[0101] According to the extension length control method of the intramedullary extension system in this application, the back electromotive force signal of each phase winding is calculated based on the voltage balance equation of each phase winding of the electromagnetic actuator, the current data of each phase winding, the voltage data of each phase winding, and the resistance and inductance parameters of the electromagnetic actuator. The phase of the permanent magnet rotor is then calculated based on the back electromotive force signal of each phase winding. The permanent magnet rotor is then subjected to closed-loop position control through a position closed-loop control system, and the extension length is controlled in a closed-loop manner based on a preset internal transmission mechanism of the intramedullary extension nail. This solves the problem that existing intramedullary extension systems cannot achieve precise control of the extension amount, realizes closed-loop position control of the permanent magnet rotor, and thus achieves precise control of the extension length of the intramedullary extension system.

[0102] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0103] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0104] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A device for controlling the extension length of an intramedullary lengthening system, characterized in that, include: The data acquisition module is used to acquire current and voltage data from the three-phase windings of the electromagnetic driver. The back electromotive force calculation module is used to calculate the back electromotive force signal of each phase winding based on the voltage balance equation of each phase winding of the electromagnetic driver, the current data of each phase winding, the voltage data of each phase winding, and the resistance and inductance parameters of the electromagnetic driver. The phase calculation module is used to calculate the phase of the permanent magnet rotor based on the back electromotive force signal of each phase winding. The vector control module is used to build a position closed-loop control system for the electromagnetic actuator based on the phase of the permanent magnet rotor, so as to perform position closed-loop control on the permanent magnet rotor through the position closed-loop control system. The extension length control module is used to perform closed-loop control of the extension length based on the preset internal transmission mechanism of the intramedullary extension nail after the position closed-loop control system performs position closed-loop control of the permanent magnet rotor.

2. The apparatus according to claim 1, characterized in that, The data acquisition module includes: A current detection component is used to collect current data on the three-phase windings of the electromagnetic driver. A voltage detection component is used to collect voltage data on the three-phase windings of the electromagnetic driver. The sampling frequency setting unit is used to dynamically adjust the sampling frequency according to the control accuracy requirements.

3. The apparatus according to claim 1, characterized in that, The phase calculation module includes: The projection unit is used to orthogonally project the back electromotive force signal of each phase winding to obtain the components of the back electromotive force signal of each phase winding in the orthogonal coordinate system. The calculation unit is used to perform arctangent calculation on the component of the back electromotive force signal of each phase winding in the orthogonal coordinate system to obtain the phase of the permanent magnet rotor.

4. The apparatus according to claim 1, characterized in that, The vector control module further includes: A current loop control circuit is used to perform coordinate transformation based on the phase of the permanent magnet rotor and to perform decoupled calculations of the phase and current amplitude of the permanent magnet rotor. A speed loop control circuit is used for closed-loop speed control of the permanent magnet rotor; A position loop control circuit is used to perform closed-loop position control on the permanent magnet rotor.

5. The apparatus according to claim 1, characterized in that, The back electromotive force calculation module also includes: The filtering unit is used to filter the back electromotive force signal.

6. The apparatus according to claim 1, characterized in that, The phase of the back electromotive force signal is orthogonal to the phase of the permanent magnet rotor.

7. The apparatus according to claim 1, characterized in that, The electromagnetic actuator is made of three-phase copper wire wound on a silicon steel core.

8. A method for controlling the extension length of an intramedullary lengthening system, characterized in that, Using the intramedullary lengthening system extension length control device as described in any one of claims 1-7, wherein the method comprises the following steps: The data acquisition module is used to acquire current and voltage data on the three-phase windings of the electromagnetic driver. The back electromotive force calculation module calculates the back electromotive force signal of each phase winding based on the voltage balance equation of each phase winding of the electromagnetic driver, the current data of each phase winding, the voltage data of each phase winding, and the resistance and inductance parameters of the electromagnetic driver. The phase of the permanent magnet rotor is obtained by using the phase calculation module to calculate based on the back electromotive force signal of each phase winding; The vector control module is used to build a position closed-loop control system for the electromagnetic actuator based on the phase of the permanent magnet rotor, so as to perform position closed-loop control of the permanent magnet rotor through the position closed-loop control system. After the permanent magnet rotor is controlled in a closed-loop position by the position closed-loop control system, the extension length is controlled in a closed-loop manner based on the preset internal transmission mechanism of the intramedullary extension nail using the extension length control module.

9. The method according to claim 8, characterized in that, The step of using the phase calculation module to calculate the phase of the permanent magnet rotor based on the back electromotive force signal of each phase winding includes: The back electromotive force signal of each phase winding is orthogonally projected using a projection unit to obtain the components of the back electromotive force signal of each phase winding in an orthogonal coordinate system. The phase of the permanent magnet rotor is obtained by calculating the arctangent of the back electromotive force signal of each phase winding in the orthogonal coordinate system using a computing unit.

10. The method according to claim 8, characterized in that, The closed-loop position control of the permanent magnet rotor via the position closed-loop control system includes: Using a current loop control circuit, coordinate transformation is performed based on the phase of the permanent magnet rotor, and decoupling calculations are performed on the phase and current amplitude of the permanent magnet rotor. The rotational speed of the permanent magnet rotor is controlled in a closed-loop manner using a rotational speed loop control circuit. The permanent magnet rotor is subjected to closed-loop position control using a position loop control circuit.

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