Animal autonomous hindlimb muscle force measurement system and method based on controllable magnetic force load

Abstract

The application discloses an animal autonomous hind limb muscle strength measuring system and method based on a controllable magnetic force load, relates to the technical field of animal autonomous hind limb muscle strength measurement, and comprises the following steps: a magnetic force response composite module is detachably attached to the hind limbs of animals and is magnetically coupled with a programmable electromagnetic load table module; a behavior excitation induction module drives autonomous movement of animals through multi-mode stimulation; a sensing and judging capturing module monitors related data in multiple dimensions and outputs a trigger signal; a control and record latching module synchronously regulates the working states of various modules and latches key parameters; and a data conversion and processing module converts parameters into muscle strength values. The measuring method completes measurement through fixing and positioning, parameter setting, synchronous triggering, data acquisition, parameter latching and muscle strength conversion, realizes precise synchronization of load dynamic regulation and the measuring process, reduces animal stress reaction and human intervention, improves the accuracy, repeatability and standardization degree of measurement, and is suitable for biomedical and exercise physiology related research scenes.

Description

Technical Field

[0001] This invention relates to the field of animal autonomous hind limb muscle strength measurement technology, and in particular to an animal autonomous hind limb muscle strength measurement system and method based on controllable magnetic load. Background Technology

[0002] Animal hindlimb muscle strength measurement is a key technical means in biomedicine, exercise physiology and other fields to study animal motor function, neuromuscular regulation mechanisms and the pathological process of related diseases. It is widely used in research scenarios such as spinal cord injury repair, treatment of bone and joint diseases, and intervention for muscle atrophy. Traditional measurement methods mostly rely on artificial assisted loading and mechanical restraint, which are difficult to simulate the muscle force output characteristics of animals in natural movement states. Moreover, the measurement process is prone to stress responses in animals due to external force intervention, affecting the authenticity and reliability of the measurement data. With the continuous improvement of research requirements for measurement accuracy, autonomy and repeatability, there is an urgent need for a standardized measurement system that can achieve controllable load adjustment, adapt to the autonomous movement behavior of animals, and reduce human intervention, so as to meet the needs of accurate measurement of hindlimb muscle strength in different species and physiological states.

[0003] Existing technologies suffer from two core defects: First, the load adjustment flexibility is insufficient. Most measuring devices adopt fixed load or stepped load designs, which cannot dynamically adjust the load size and loading method in real time according to individual animal differences and movement status. This makes it difficult to match the changes in muscle force output during the animal's autonomous movement, resulting in measurement data that cannot fully reflect the true muscle force level of the animal's hind limbs. Second, the coordination between sensing and triggering is lacking. There is a response delay between the behavioral stimulation, load application and signal capture modules in traditional systems, which cannot accurately synchronize the timing of animal movement behavior and muscle force signal acquisition. Moreover, the sensing units mostly rely on a single detection method, which is easily affected by environmental interference or animal movement posture, causing signal distortion or trigger misjudgment, reducing the accuracy and repeatability of the measurement results. Summary of the Invention

[0004] In order to overcome the shortcomings and deficiencies of the existing technology, the present invention provides an animal autonomous hindlimb muscle strength measurement system and method based on controllable magnetic load.

[0005] The technical solution adopted in this invention is an animal autonomous hindlimb muscle strength measurement system based on controllable magnetic load, comprising: a magnetic response composite module, a programmable electromagnetic load stage module, a behavior stimulation and induction module, a sensing and judgment capture module, a control recording and latching module, and a data conversion and processing module. The magnetic response composite module is detachably attached to the hind limb of the animal to be tested via a flexible restraint structure. Its rigid base is embedded with a permanent magnet and coupled to the magnetic field of the programmable electromagnetic load stage module. The behavior stimulation and induction module is signal-connected to the control recording and latching module and is triggered by it. The sensing and judgment capture module monitors the relative position changes of the magnetic response composite module and the programmable electromagnetic load stage module in real time and outputs a trigger signal. The control recording and latching module synchronously regulates the current output of the programmable electromagnetic load stage module and the working state of the behavior stimulation and induction module. After receiving the signal from the sensing and judgment capture module, it latches the current parameters. The data conversion and processing module calls the preset calibration database to convert the current parameters into stress value parameters. All modules work together through wired or wireless signal transmission.

[0006] Furthermore, the behavior stimulation and induction module includes: a tail mild electrical stimulation unit, an acoustic and optical stimulation triggering unit, a nest orientation induction unit, and a food attraction driving unit. The tail mild electrical stimulation unit applies an electrical signal of preset duration and intensity to the animal's tail through contact electrodes. The acoustic and optical stimulation triggering unit generates calibrated frequency sound waves and light signals to act on the animal's senses. The nest orientation induction unit has a cavity structure adapted to the animal's habitat on the opposite side of the programmable electromagnetic load platform module. The food attraction driving unit places the animal's preferred food source and adjusts its relative distance to the animal through a movable mechanism. Each unit is connected to the control recording latch module through a signal switching switch.

[0007] Furthermore, the sensing and detection module includes: a high-speed image acquisition unit, a laser displacement detection unit, an electromagnetic induction sensing unit, and a pressure trigger sensing unit. The high-speed image acquisition unit captures the contact area between the magnetic response composite module and the programmable electromagnetic load stage module at a preset frame rate and transmits image data. The laser displacement detection unit emits a laser beam to the surface of the magnetic response composite module and receives the reflected signal to calculate the displacement. The electromagnetic induction sensing unit senses the coupling state between the two by detecting changes in the magnetic field. The pressure trigger sensing unit is set on the contact surface of the programmable electromagnetic load stage module and collects pressure signals. Each unit converts the detection data into electrical signals and transmits them to the control, recording, and latching module.

[0008] Furthermore, the control recording latch module includes: a synchronous trigger control unit, a current regulation output unit, a signal receiving and processing unit, and a parameter latch storage unit. The synchronous trigger control unit generates a synchronization signal and sends it to the behavior excitation and induction module and the current regulation output unit respectively. The current regulation output unit changes the power supply current of the programmable electromagnetic load platform module according to a preset program. The signal receiving and processing unit filters and amplifies the electrical signal transmitted by the sensing and judgment capture module. The parameter latch storage unit freezes the current current parameter and stores it in a designated storage area the instant it receives the trigger signal. Each unit interacts with the other through an internal bus.

[0009] Furthermore, the data conversion and processing module employs a muscle strength calculation model: ,in For the voluntary muscle strength of the animal's hind limbs, This is the latching current value. The permeability of free space, The number of turns of the electromagnet coil. The cross-sectional area of ​​the iron core is... The distance between the magnetic response unit and the platform. This is the angle correction factor. This represents the change in the angle of the animal's hind limbs during the push-off motion. Density of the magnetic response unit material. The instantaneous velocity during pedaling.

[0010] Furthermore, the programmable electromagnetic load stage module adopts a magnetic field strength adjustment model: ,in The magnetic field strength, The permeability of free space, The number of coil turns. For supply current, The coil fill factor, The length of the air gap. The length of the iron core. The relative permeability of the iron core. For temperature coefficient, This represents the difference between the ambient temperature and the standard temperature.

[0011] Furthermore, the magnetic response composite module adopts a coupled magnetic calculation model: ,in For coupling magnetic force, The magnetic field strength of the platform, Let be the cross-sectional area of ​​the permanent magnet. The permeability of free space, The angle between the magnetization direction of the permanent magnet and the direction of the magnetic field. The magnetization intensity of the permanent magnet. The magnetization intensity of the electromagnet core. This is the distance between the permanent magnet and the iron core.

[0012] Furthermore, the behavior stimulation induction module employs a stimulus intensity adaptation model: ,in For stimulus intensity parameters, For species fitness coefficient, For the animal's weight, For the basic activity speed of animals, For the duration of stimulation, This is the environmental correction factor. This represents the difference between ambient brightness and standard brightness.

[0013] Furthermore, the sensing and detection module adopts a separate decision-making model: ,in The threshold for separation determination, These are the initial position coordinates. For real-time location coordinates, For image acquisition frame rate, For standard frame rate, For speed correction factor, This represents the change in electromagnetically induced voltage.

[0014] A method for measuring the voluntary hind limb muscle strength of an animal based on a controllable magnetic load is disclosed. This method is applied to an animal voluntary hind limb muscle strength measurement system based on a controllable magnetic load and includes the following steps: S1, fixing the magnetic response composite module to the hind limb of the animal to be tested using an adjustable restraint structure, ensuring that the permanent magnet of the rigid base faces the contact surface of the programmable electromagnetic load stage module and maintains a preset initial distance; S2, positioning the animal's torso using a flexible fixing mechanism, ensuring that the hind limb is in a naturally extended state and that the contact surface of the magnetic response composite module is parallel to that of the programmable electromagnetic load stage module; S3, setting the initial current parameters, behavioral excitation mode, and sensing judgment threshold by controlling the recording latch module, and initiating system preheating. The program brings each module to a stable working state; S4, the control recording latch module synchronously triggers the behavior stimulation and induction module and the programmable electromagnetic load stage module. The behavior stimulation and induction module outputs a preset stimulation signal, and the programmable electromagnetic load stage module generates a corresponding magnetic field according to the set current parameters; S5, the sensing judgment and capture module continuously collects position, displacement, magnetic field or pressure-related data and transmits it to the control recording latch module. When the detected data reaches the set threshold, the control recording latch module immediately latches the current current parameters; S6, the data conversion and processing module calls the preset calibration database and the corresponding calculation model to convert the latched current parameters into the animal's hind limb voluntary muscle strength values ​​and stores or outputs them according to the set format.

[0015] Beneficial Effects: This invention proposes an animal autonomous hindlimb muscle strength measurement system and method based on controllable magnetic load. A programmable electromagnetic load stage module enables dynamic and precise load control, allowing flexible adjustment of loading parameters according to individual animal characteristics and movement states. This breaks the limitations of traditional fixed or stepped loads, perfectly matching muscle strength output changes during autonomous movement and ensuring that measurement data comprehensively reflects the true muscle strength level. Relying on the multi-unit collaborative stimulation mode of the behavior stimulation and induction module, combined with the multi-dimensional detection mechanism of the sensing judgment and capture module and the synchronous triggering function of the control recording latch module, the synergy of behavior stimulation, load application, and signal capture is significantly improved. This eliminates response delays between modules, reduces signal distortion caused by environmental interference and posture effects, and significantly improves measurement accuracy and repeatability. Simultaneously, the detachable and flexible fit design of the magnetic response composite module reduces animal stress responses, and the data conversion and processing module achieves precise parameter conversion through a preset calibration database and a dedicated calculation model. The entire system requires no complex manual intervention, ensuring both animal autonomy and standardized and efficient muscle strength measurement, meeting the core requirements for measurement accuracy, flexibility, and reliability in different research scenarios. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a diagram showing the system module composition of the present invention; Figure 2 This is a flowchart of the method steps of the present invention. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] like Figure 1 As shown, an animal autonomous hind limb muscle strength measurement system based on controllable magnetic load includes: a magnetic response composite module, a programmable electromagnetic load stage module, a behavior stimulation and induction module, a sensing and judgment capture module, a control recording and latching module, and a data conversion and processing module. The magnetic response composite module is detachably attached to the hind limb of the animal to be tested via a flexible restraint structure. Its rigid base is embedded with a permanent magnet and coupled to the magnetic field of the programmable electromagnetic load stage module. The behavior stimulation and induction module is signal-connected to the control recording and latching module and is triggered by it. The sensing and judgment capture module monitors the relative position changes of the magnetic response composite module and the programmable electromagnetic load stage module in real time and outputs a trigger signal. The control recording and latching module synchronously regulates the current output of the programmable electromagnetic load stage module and the working state of the behavior stimulation and induction module. After receiving the signal from the sensing and judgment capture module, it latches the current parameters. The data conversion and processing module calls the preset calibration database to convert the current parameters into stress value parameters. All modules work together through wired or wireless signal transmission.

[0020] The overall thickness of the magnetic response composite module is controlled at 3-5 mm. It is made of medical-grade silicone and a lightweight aluminum alloy rigid substrate. The rigid substrate is sized to fit the contours of common laboratory animal hind limbs, with a length of 8-12 cm and a width of 3-5 cm. Two to four neodymium iron boron permanent magnets are embedded inside the substrate. Each permanent magnet measures 10×5×3 mm and has a magnetic flux density of 1.2-1.5 Tesla. The permanent magnets are arranged in parallel at equal intervals with consistent magnetization directions. This unit adheres to the animal's hind limb through an inner flexible silicone layer. The flexible restraint structure uses an adjustable Velcro design with a restraint tension range of 5-15 Newtons, ensuring a stable fit without affecting blood circulation. During implementation, the tightness of the restraint structure is first adjusted according to the circumference of the animal's hind limbs, so that the area where the permanent magnet is located is aligned with the center of the hind leg muscle group. Quick installation and removal are achieved through detachable buckles. The initial vertical distance between the permanent magnet and the programmable electromagnetic load stage module is controlled at 5-10 mm to ensure stable magnetic field coupling. Its core function is to convert the animal's hind limb kicking action into magnetic field interaction, providing a physical carrier for muscle force detection. At the same time, the structural design that combines flexibility and rigidity takes into account both the degree of freedom of movement and the stability of detection.

[0021] The programmable electromagnetic load platform module adopts a U-shaped iron core structure. The iron core is made of DT4 electrical pure iron with a cross-sectional area of ​​20×20 mm. Enamelled copper wire coils are wound around the iron core, with 1500-2500 turns and wire diameter of 0.5-0.8 mm. The DC resistance of the coil is 5-8 ohms. The load platform operates at a voltage range of 12-24 volts, with a maximum output current of 5 amps. Pulse width modulation (PWM) technology enables continuous current adjustment within the range of 0.1-5 amps, with an adjustment accuracy of 0.01 amps. The load platform surface is coated with a wear-resistant ceramic coating, with a contact area of ​​15×15 cm. The flatness error of the platform surface does not exceed 0.1 mm. Shock-absorbing feet and a leveling knob are installed at the bottom to ensure that the vibration amplitude during operation is less than 0.05 mm. During implementation, the load station is connected to the control recording latch module via an RS485 communication interface, receives current adjustment commands and provides real-time feedback on the working status, and dynamically adjusts the magnetic field strength during animal movement according to a preset program. The magnetic field strength adjustment range is 0.1-0.8 Tesla, with a response time of less than 10 milliseconds. It can accurately match the dynamic changes in the muscle force output of the animal's hind limbs and provide a controllable load environment for muscle force measurement of different intensities.

[0022] The behavior stimulation and induction module integrates four stimulation units. The tail mild electrical stimulation unit uses platinum electrodes with a diameter of 1 mm, a stimulation voltage range of 0.5-5 volts, a pulse frequency of 1-10 Hz, a pulse width of 0.1-1 ms, and a single stimulation duration of 1-5 seconds. The sound and light stimulation trigger unit has a built-in high-frequency speaker and LED light source. The speaker output frequency is 1000-5000 Hz, the volume range is 40-80 dB, the LED light source wavelength is 450-650 nm, and the brightness is adjustable from 100-1000 lumens. The nest attraction induction unit has a cavity size of 30×20×20 cm, and the inner wall is lined with a soft material similar to the animal's habitat. The cavity temperature is maintained at 25-28 degrees Celsius. The food attraction drive unit uses a stepper motor to drive a sliding platform with a platform movement speed of 1-5 cm / s, a movement range of 0-50 cm, and a food placement slot capacity of 50 ml. During implementation, the component receives the trigger signal from the control recording latch module through a signal switching switch, and can activate each stimulation unit individually or in combination. The stimulation parameters can be adjusted according to the type of experimental animal (such as rats and mice). For example, for rats, the electrical stimulation voltage can be set to 1-3 volts and the sound wave frequency to 2000-3000 Hz. Through multi-mode stimulation, the animal is driven to produce autonomous pedaling movements, ensuring that the muscle strength measurement scenario conforms to the animal's natural behavioral characteristics.

[0023] The sensing and detection module includes four detection units: a high-speed image acquisition unit using a CMOS camera with a resolution of 1920×1080 pixels, an adjustable frame rate of 30-240 frames / second, a lens focal length of 16-25 mm, a shooting distance of 30-50 cm, and an image transmission delay of less than 5 milliseconds; a laser displacement detection unit using a semiconductor laser with an emission wavelength of 650 nm, a measurement range of 0-100 mm, a measurement accuracy of ±0.01 mm, and a sampling frequency of 1000 Hz; an electromagnetic induction sensing unit using a Hall sensor with a detection range of 0.01-1 Tesla, a sensitivity of 10 mV / Gauss, and a response time of less than 1 millisecond; and a pressure trigger sensing unit using a piezoelectric pressure sensor with a measurement range of 0-50 Newtons, an accuracy of ±0.1 Newtons, and a sampling frequency of 2000 Hz. During implementation, all units work synchronously. The high-speed image acquisition unit continuously captures images of the contact area between the magnetic response composite module and the load platform. The laser displacement detection unit measures the relative displacement between the two in real time. The electromagnetic induction sensing unit monitors the magnetic field coupling state. The pressure trigger sensing unit collects the contact pressure signal. All detection data are converted into standard electrical signals of 0-5 volts and transmitted to the control recording latch module via shielded cable at a transmission rate of 1 Mbps. This ensures the real-time performance and accuracy of multi-dimensional data, providing a reliable triggering and judgment basis for muscle strength measurement.

[0024] The control recording latch module is based on a 32-bit ARM microcontroller with a clock frequency of 72 MHz, a built-in 12-bit analog-to-digital converter, and a sampling rate of 1 MHz. The synchronous trigger control unit outputs a pulse signal with an amplitude of 5 volts, a pulse width of 10 microseconds, and a trigger delay of less than 1 microsecond, which can simultaneously drive the behavior excitation and induction module and the current regulation output unit. The current regulation output unit uses a DC regulated power supply module with an output voltage ripple of less than 5 millivolts and a current stability of ±0.1%. The signal receiving and processing unit has a built-in second-order low-pass filter with a cutoff frequency of 100 Hz and an amplifier gain adjustable range of 1-100 times, which can effectively suppress environmental noise. The parameter latch storage unit uses an SD card storage module with a storage capacity of no less than 8GB and a data write speed of 10MB / s, which can record the current parameters, timestamps, and data from each sensor for each measurement, and the stored data is retained for no less than 10 years. During implementation, the unit achieves data interaction between modules through an internal bus with a response time of less than 20 milliseconds. It can automatically complete the coordinated operation of stimulus triggering, load adjustment, signal acquisition, and parameter latching according to a preset program. At the same time, it supports setting parameters and reading stored data through host computer software, ensuring the automation and traceability of the measurement process.

[0025] The data conversion and processing module employs an industrial-grade embedded processor with a main frequency of 1.2GHz, 512MB of DDR3 memory, and 8GB of flash memory. Its preset calibration database includes muscle force calibration curves corresponding to different load currents, spacings, and angles, with a calibration accuracy of ±0.2 Newtons. The database supports online updates and custom calibration. The module has multi-channel data input interfaces, capable of receiving current parameters and sensor data transmitted from the control recording latch module. The data transmission protocol is Modbus RTU, with a transmission rate of 9600-115200bps. During implementation, the module first verifies the validity of the received current parameters, eliminating abnormal data. Then, it calls the preset calibration database and, combined with auxiliary parameters such as the real-time spacing and hind limb kicking angle of the magnetic response composite module and the programmable electromagnetic load stage module, uses an interpolation algorithm to convert the current parameters into corresponding muscle force values. The muscle force value calculation resolution is 0.01 Newtons, and the data processing latency is less than 50 milliseconds. The processed muscle strength values ​​are stored in CSV format and can be output to a computer or data acquisition instrument in real time via RS232 or Ethernet interface. It supports interface with the laboratory information management system to realize automated analysis and archiving of measurement data, providing standardized muscle strength data support for subsequent research.

[0026] Preferably, the behavior stimulation and induction module includes: a tail mild electrical stimulation unit, an acoustic and optical stimulation triggering unit, a nest orientation induction unit, and a food attraction driving unit. The tail mild electrical stimulation unit applies an electrical signal of preset duration and intensity to the animal's tail through contact electrodes. The acoustic and optical stimulation triggering unit generates calibrated frequency sound waves and light signals to act on the animal's senses. The nest orientation induction unit has a cavity structure adapted to the animal's habitat on the opposite side of the programmable electromagnetic load platform module. The food attraction driving unit places the food source preferred by the animal and adjusts its relative distance to the animal through a movable mechanism. Each unit is connected to the control recording latch module through a signal switching switch.

[0027] Specifically, the four units of the behavior stimulation and induction module work together to drive autonomous animal movement. The contact electrodes of the tail mild electrical stimulation unit are made of biocompatible platinum, with a diameter of 1 mm. They are connected to the pulse generator via wires and can output an electrical signal with a voltage of 0.5-5 volts, a frequency of 1-10 Hz, and a width of 0.1-1 milliseconds. A single stimulation lasts for 1-5 seconds. The electrodes are attached to the skin of the animal's tail at 1 / 3 of its length to ensure that the stimulation is mild and does not cause tissue damage. The high-frequency speaker of the sound and light stimulation trigger unit is installed on the side of the experimental device, outputting sound waves of 1000-5000 Hz. The volume is controlled at 40-80 decibels to avoid animal stress. The LED light source is installed on the device. The top-mounted unit emits light with a wavelength of 450-650 nanometers, with adjustable brightness between 100-1000 lumens, attracting animal attention through dual stimulation of light and sound waves. The nest-oriented induction unit's cavity is made of ABS material, measuring 30×20×20 cm, with its inner wall lined with soft velvet matching the animal's habitat. It incorporates a temperature sensor and heating module to stabilize the cavity temperature at 25-28 degrees Celsius, simulating a safe habitat. The food-attracting drive unit's sliding platform is driven by a stepper motor, moving at a speed of 1-5 cm / s with a stroke of 0-50 cm. The food placement slot is made of corrosion-resistant plastic, with a capacity of 50 ml, allowing for the placement of the animal's preferred food. During implementation, a signal switching switch receives commands from the control recording latch module, enabling the individual activation of one unit or the combined activation of multiple units. Multi-mode stimulation covers different animal senses, driving continuous and stable autonomous pedaling movements, ensuring the consistency and reliability of the animal's movement state during muscle strength measurement.

[0028] Preferably, the sensing and detection module includes: a high-speed image acquisition unit, a laser displacement detection unit, an electromagnetic induction sensing unit, and a pressure trigger sensing unit. The high-speed image acquisition unit captures images of the contact area between the magnetic response composite module and the programmable electromagnetic load stage module at a preset frame rate and transmits image data. The laser displacement detection unit emits a laser beam to the surface of the magnetic response composite module and receives the reflected signal to calculate the displacement. The electromagnetic induction sensing unit senses the coupling state between the two by detecting changes in the magnetic field. The pressure trigger sensing unit is located on the contact surface of the programmable electromagnetic load stage module and collects pressure signals. Each unit converts the detection data into electrical signals and transmits them to the control, recording, and latching module.

[0029] Specifically, the four units of the sensing and detection module achieve data acquisition and triggering judgment from multiple dimensions. The high-speed image acquisition unit uses a 1920×1080 pixel CMOS camera with a lens focal length of 16-25 mm, installed at a distance of 30-50 cm from the measurement area, with an adjustable frame rate of 30-240 frames / second. It continuously captures the contact interface between the magnetic response composite module and the programmable electromagnetic load platform module. The image data is transmitted via a shielded cable with a delay of less than 5 milliseconds, clearly capturing the contact state at the moment of pedaling. The laser displacement detection unit's semiconductor laser emits a 650 nm wavelength laser, which vertically illuminates the magnetic response composite module. The measurement range is 0-100 mm, with an accuracy of ±0.01 mm, a sampling frequency of 1000 Hz, and real-time output of relative displacement data. The Hall sensor of the electromagnetic induction sensing unit is installed inside the programmable electromagnetic load stage module, with a detection range of 0.01-1 Tesla, a sensitivity of 10 mV / Gauss, and a response time of less than 1 ms. It determines the interaction state between the two by monitoring changes in magnetic field coupling strength. The piezoelectric pressure sensor of the pressure trigger sensing unit is embedded in the contact surface of the load stage, with a measurement range of 0-50 Newtons, an accuracy of ±0.1 Newtons, and a sampling frequency of 2000 Hz, directly acquiring the pressure signal generated by pedaling. During implementation, all units work synchronously, converting image, displacement, magnetic field, and pressure data into 0-5 volt standard electrical signals. After filtering, these signals are transmitted to the control, recording, and latching module, providing multi-dimensional data support for accurately determining the timing of pedaling actions and latching key parameters, avoiding misjudgments or omissions caused by a single detection method.

[0030] Preferably, the control recording latch module includes: a synchronous trigger control unit, a current regulation output unit, a signal receiving and processing unit, and a parameter latch storage unit. The synchronous trigger control unit generates a synchronization signal and sends it to the behavior excitation and induction module and the current regulation output unit respectively. The current regulation output unit changes the power supply current of the programmable electromagnetic load module according to a preset program. The signal receiving and processing unit filters and amplifies the electrical signal transmitted by the sensing and judgment capture module. The parameter latch storage unit freezes the current current parameter and stores it in a designated storage area the instant it receives the trigger signal. Each unit interacts with the other through an internal bus.

[0031] Specifically, the four units of the control recording latch module achieve coordinated system control and data storage. The synchronous trigger control unit, based on a 32-bit ARM microcontroller, outputs a 5-volt, 10-microsecond pulse signal with a trigger delay of less than 1 microsecond. This signal is simultaneously sent to the behavior stimulation induction module and the current regulation output unit to ensure precise synchronization between stimulus initiation and load application. The DC regulated power supply module of the current regulation output unit outputs a 12-24 volt voltage with a voltage ripple of less than 5 millivolts. Pulse width modulation technology is used to regulate the output current, with a current range of 0.1-5 amps and a stability of ±0.1%. The system precisely controls the magnetic field strength of the programmable electromagnetic load stage module. The signal receiving and processing unit incorporates a second-order low-pass filter with a 100Hz cutoff frequency to filter high-frequency noise. The amplifier gain is adjustable from 1 to 100 times, amplifying the weak electrical signals transmitted by the sensing and capture module to a processable range, ensuring signal integrity. The parameter latching and storage unit uses an SD card with a capacity of 8GB or more and a data write speed of 10MB / s. Upon receiving a trigger signal, it immediately freezes the current parameters, timestamp, and raw data from each sensor. The stored data is retained for at least 10 years, supporting subsequent traceability and analysis. During implementation, each unit interacts with the others via an internal bus, with an overall response time of less than 20 milliseconds. It automatically completes the entire "trigger-adjustment-acquisition-latch" process according to a preset program. Simultaneously, it supports remote parameter setting and data retrieval via host computer software, achieving automated control of the measurement process and secure data storage.

[0032] Preferably, the data conversion and processing module employs a muscle strength calculation model: ,in For the voluntary muscle strength of the animal's hind limbs, This is the latching current value. The permeability of free space, The number of turns of the electromagnet coil. The cross-sectional area of ​​the iron core is... The distance between the magnetic response unit and the platform. This is the angle correction factor. This represents the change in the angle of the animal's hind limbs during the push-off motion. Density of the magnetic response unit material. The instantaneous velocity during pedaling.

[0033] Specifically, the muscle strength calculation model is based on the coupling principle of electromagnetic and mechanical forces. First, the magnetic force generated by the electric magnet is derived using the Ampere force formula. Then, combining the coupling effect between the permanent magnet and the electromagnet, geometric parameters and physical constants are introduced for correction. Simultaneously, the influence of the animal's hind limb pushing angle and instantaneous velocity on muscle strength output is considered, supplementing the model with angle correction and velocity correlation terms to form a complete muscle strength calculation logic. Parameter values ​​were determined through multiple calibration experiments. The vacuum permeability is a physical constant. The number of coil turns is designed to be 1500-2500 turns based on the load platform structure. The core cross-sectional area matches the coil size, which is set to 20×20 square millimeters, with a spacing controlled at 5-10 millimeters. The angle correction coefficient is calibrated to 0.8-1.2 through muscle strength comparison experiments at different pushing angles. The material density is set to 7.5-7.8 g / cm³ based on the permanent magnet material. The instantaneous velocity is calculated from data collected by a laser displacement sensor, with a value range of 0.1-0.5 m / s. During implementation, the data conversion and processing module calls a preset calibration database, inputs latching current values, measured distances, angle changes, and velocity data, and calculates the magnetic field force and correction terms step by step according to the derivation logic. After superposition, the voluntary muscle force value of the animal's hind limb is obtained. This formula solves the problem of neglecting the influence of motion state in the calculation of single electromagnetic force through multi-parameter collaborative correction, ensuring the accuracy of muscle force calculation. The parameter values ​​cover the commonly used experimental range and are adaptable to different measurement scenarios.

[0034] Preferably, the programmable electromagnetic load platform module adopts a magnetic field strength adjustment model: ,in The magnetic field strength, The permeability of free space, The number of coil turns. For supply current, The coil fill factor, The length of the air gap. The length of the iron core. The relative permeability of the iron core. For temperature coefficient, This represents the difference between the ambient temperature and the standard temperature.

[0035] Specifically, the magnetic field strength adjustment model is based on Ohm's law for magnetic circuits, combined with the principle of electromagnetic induction of coils, considering the influence of the coil filler coefficient on the magnetic field, introducing a temperature correction term to compensate for the magnetic field deviation caused by changes in ambient temperature, and incorporating the core permeability and geometric dimensions to form a precisely adjustable magnetic field strength calculation model. In the parameter values, the vacuum permeability is a fixed physical constant; the number of coil turns is consistent with the design of the programmable electromagnetic load platform module coil, at 1500-2500 turns; the filler coefficient is calibrated to 0.6-0.8 based on the coil winding process; the air gap length corresponds to a distance of 5-10 mm between the magnetic response unit and the platform; the core length is set to 8-12 cm according to the load platform structure; the relative permeability is set to 1000-3000 based on the characteristics of DT4 electrical pure iron material; the temperature coefficient is determined to be 0.001-0.003 degrees Celsius through magnetic field testing under different temperature environments; and the temperature difference is the deviation between the ambient temperature and the standard temperature of 25 degrees Celsius. During implementation, the control recording latch module, based on the preset target magnetic field strength value and input parameters such as current and temperature, calculates and derives the required current output value using a formula, thereby driving the programmable electromagnetic load stage module to generate the corresponding magnetic field. This formula achieves precise adjustment of the magnetic field strength through dual correction of magnetic circuit parameters and environmental factors. The parameter values ​​are closely aligned with the load stage hardware design, ensuring that the adjustment logic matches the hardware performance.

[0036] Preferably, the magnetic response composite module adopts a coupled magnetic calculation model: ,in For coupling magnetic force, The magnetic field strength of the platform, Let be the cross-sectional area of ​​the permanent magnet. The permeability of free space, The angle between the magnetization direction of the permanent magnet and the direction of the magnetic field. The magnetization intensity of the permanent magnet. The magnetization intensity of the electromagnet core. This is the distance between the permanent magnet and the iron core.

[0037] Specifically, the coupled magnetic force calculation model is based on the principle of magnet-magnetic interaction in magnetostatics. It calculates the force exerted by the electromagnet's magnetic field on the permanent magnet and the magnetostatic force between the two magnets, respectively. The total coupled magnetic force is obtained through vector superposition. An angle parameter is introduced to correct force deviations caused by inconsistencies between the magnetization direction and the magnetic field direction. In the parameter values, the magnetic field strength is output by the programmable electromagnetic load module, ranging from 0.1 to 0.8 Tesla; the cross-sectional area of ​​the permanent magnet is adapted to the rigid substrate at 10 × 15 mm²; the vacuum permeability is a physical constant; the angle is obtained through image acquisition unit analysis, ranging from 0 to 90 degrees; the magnetization intensity of the permanent magnet is set to 1000-1200 kA / m based on the characteristics of NdFeB material; the core magnetization intensity is calculated from the magnetic field strength and relative permeability; and the spacing is consistent with the magnetic response unit installation parameters, at 5-10 mm. During implementation, the sensing and capture module collects data such as magnetic field strength, angle, and spacing, and substitutes them into the formula to calculate the coupled magnetic force, providing basic data for muscle force conversion. This formula accurately reflects the coupling effect between magnets through the superposition of component forces and the correction of the included angle. The parameter values ​​cover the magnet characteristics and installation conditions, ensuring that the calculation results are consistent with the actual coupling state.

[0038] Preferably, the behavior stimulation induction module adopts a stimulus intensity adaptation model: ,in For stimulus intensity parameters, For species fitness coefficient, For the animal's weight, For the basic activity speed of animals, For the duration of stimulation, This is the environmental correction factor. This represents the difference between ambient brightness and standard brightness.

[0039] Specifically, the stimulus intensity adaptation model combines animal physiological characteristics with the correlation between body weight and basal metabolic rate, introducing a body weight correction term. It also considers the impact of movement speed on stimulus sensitivity, supplementing it with a speed correlation term, and incorporates environmental brightness correction to compensate for the interference of light on animal behavior, forming a stimulus intensity calculation model adapted to different animal states. In the parameter values, the species adaptation coefficient is calibrated through stimulus response experiments with different species (rats and mice), with values ​​of 0.8-1.0 for rats and 0.6-0.8 for mice. Animal body weight is determined based on actual measurements of the experimental subjects, ranging from 20-300 grams. Basal activity speed is derived from image analysis, ranging from 0.05-0.3 m / s. The stimulus duration is set to 1-5 seconds according to the experimental design. The environmental correction coefficient is determined to be 0.9-1.1 through behavioral tests under different brightness levels, with the brightness difference being the deviation between the actual environmental brightness and the 500 lux standard brightness. During implementation, the control recording latch module inputs data such as animal body weight, speed, and environmental brightness, calculates the adapted stimulus intensity using a formula, and drives the behavior induction module. This formula uses multi-factor synergistic adaptation to avoid behavioral abnormalities caused by excessively high or low stimulus intensity. The parameter values ​​cover the range of common experimental animals to ensure that the stimulus effect matches the animal's condition.

[0040] Preferably, the sensing and detection module adopts a separation detection model: ,in The threshold for separation determination, These are the initial position coordinates. For real-time location coordinates, For image acquisition frame rate, For standard frame rate, For speed correction factor, This represents the change in electromagnetically induced voltage.

[0041] Specifically, the separation judgment model is based on spatial geometry principles. It calculates relative displacement using three-dimensional coordinates, introduces a frame rate correction term to compensate for the impact of image acquisition speed on displacement judgment, and considers the coupling state reflected by electromagnetic induction voltage changes, supplementing it with a voltage correction term to form a multi-dimensional separation judgment threshold. In the parameter values, the initial and real-time position coordinates are jointly acquired by the laser displacement detection unit and the image acquisition unit, with a coordinate range of 0-50 cm. The image acquisition frame rate is set to 30-240 frames / second according to measurement requirements, with a standard frame rate of 120 frames / second. The speed correction coefficient is calibrated to 0.05-0.1 through correlation analysis of displacement and voltage changes. The voltage change is obtained by the electromagnetic induction sensing unit, ranging from 0-5 volts. During implementation, the sensing judgment and capture module acquires coordinate, frame rate, and voltage data in real time, substitutes them into the formula to calculate the separation judgment threshold, and triggers a latching command when the detected data exceeds the threshold. This formula improves the accuracy of separation recognition through dual judgment of spatial displacement and electromagnetic signals. The parameter values ​​cover the performance of the detection equipment and measurement conditions, avoiding false triggering caused by single-dimensional judgment.

[0042] like Figure 2 As shown, a method for measuring the voluntary hind limb muscle strength of an animal based on a controllable magnetic load is described. This method is applied to an animal voluntary hind limb muscle strength measurement system based on a controllable magnetic load and includes the following steps: S1, fixing the magnetic response composite module to the hind limb of the animal to be tested using an adjustable restraint structure, ensuring that the permanent magnet of the rigid base faces the contact surface of the programmable electromagnetic load stage module and maintains a preset initial distance; S2, positioning the animal's torso using a flexible fixing mechanism, ensuring that the hind limb to be tested is in a naturally extended state and that the contact surface of the magnetic response composite module is parallel to that of the programmable electromagnetic load stage module; S3, setting the initial current parameters, behavioral excitation mode, and sensing judgment threshold by controlling the recording latch module, and starting the system. The preheating process brings each module to a stable working state; S4, the control recording latch module synchronously triggers the behavior stimulation and induction module and the programmable electromagnetic load stage module. The behavior stimulation and induction module outputs a preset stimulation signal, and the programmable electromagnetic load stage module generates a corresponding magnetic field according to the set current parameters; S5, the sensing judgment and capture module continuously collects position, displacement, magnetic field or pressure-related data and transmits it to the control recording latch module. When the detected data reaches the set threshold, the control recording latch module immediately latches the current current parameters; S6, the data conversion and processing module calls the preset calibration database and the corresponding calculation model to convert the latched current parameters into the animal's hind limb voluntary muscle strength values ​​and stores or outputs them according to the set format.

[0043] A system and method for measuring the hind limb muscle strength of animals based on controllable magnetic load is disclosed. In terms of load adjustment, the flexible controllability of the programmable electromagnetic load stage module allows for real-time adjustment of load parameters according to individual animal characteristics and movement status, replacing traditional fixed or stepped load designs. This perfectly matches the dynamic changes in muscle force output during voluntary movement, fundamentally solving the problem of incomplete data caused by the mismatch between load and muscle force output, ensuring that the measurement results comprehensively reflect the true muscle strength level of the animal's hind limbs. Regarding synergy and anti-interference, the system utilizes a multi-mode stimulation unit of the behavior stimulation and induction module, a multi-dimensional detection mechanism of the sensing and judgment capture module, and a synchronous triggering function of the control, recording, and latching module to achieve seamless connection between behavior stimulation, load application, and signal capture, eliminating response delays between modules. Simultaneously, the multi-dimensional detection method effectively resists the influence of environmental interference and animal movement posture, completely solving the drawbacks of signal distortion and trigger misjudgment in traditional systems.

[0044] The detachable, flexible, and conformal design of the magnetic response composite module in this invention reduces animal restraint stress, ensures the naturalness of autonomous movement, and avoids interference from human intervention in measurements. The data conversion and processing module, relying on a pre-set calibration database and a dedicated calculation model, achieves precise parameter conversion, improving measurement accuracy. The entire system requires no complex manual operation, forming a standardized measurement process. This solves the problems of traditional measurements relying on manual assistance and having poor repeatability. Furthermore, through the wired or wireless collaborative operation of each module, it balances the flexibility and efficiency of measurements, fully meeting the precision and standardization requirements for muscle strength measurement in fields such as biomedicine and exercise physiology.

[0045] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0046] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be a single item or multiple items.

[0047] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0048] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0049] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the devices, apparatuses, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0050] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A system for measuring the voluntary hind limb muscle strength of animals based on controllable magnetic load, characterized in that, include: Magnetic response composite module, programmable electromagnetic load stage module, behavior excitation and induction module, sensing judgment and capture module, control recording and latching module, and data conversion and processing module; The magnetic response composite module is detachably attached to the hind limb of the animal to be tested via a flexible restraint structure. Its rigid base is embedded with a permanent magnet and coupled to the magnetic field of the programmable electromagnetic load stage module. The behavior stimulation and induction module is signal-connected to the control recording and latching module and is triggered by it. The sensing and judgment capture module monitors the relative position changes of the magnetic response composite module and the programmable electromagnetic load stage module in real time and outputs a trigger signal. The control recording and latching module synchronously regulates the current output of the programmable electromagnetic load stage module and the working state of the behavior stimulation and induction module. After receiving the signal from the sensing and judgment capture module, it latches the current parameters. The data conversion and processing module calls the preset calibration database to convert the current parameters into stress value parameters. All modules work together through wired or wireless signal transmission.

2. The animal autonomous hindlimb muscle strength measurement system based on controllable magnetic load as described in claim 1, characterized in that, The behavior stimulation and induction module includes: a tail mild electrical stimulation unit, an acoustic and optical stimulation triggering unit, a nest orientation induction unit, and a food attraction driving unit. The tail mild electrical stimulation unit applies an electrical signal of preset duration and intensity to the animal's tail through contact electrodes. The acoustic and optical stimulation triggering unit generates calibrated frequency sound waves and light signals that act on the animal's senses. The nest orientation induction unit has a cavity structure adapted to the animal's habitat on the opposite side of the programmable electromagnetic load platform module. The food attraction driving unit places the animal's preferred food source and adjusts its relative distance to the animal through a movable mechanism. Each unit is connected to the control recording latch module through a signal switching switch.

3. The animal autonomous hindlimb muscle strength measurement system based on controllable magnetic load as described in claim 1, characterized in that, The sensing and detection module includes: a high-speed image acquisition unit, a laser displacement detection unit, an electromagnetic induction sensing unit, and a pressure trigger sensing unit. The high-speed image acquisition unit captures images of the contact area between the magnetic response composite module and the programmable electromagnetic load stage module at a preset frame rate and transmits image data. The laser displacement detection unit emits a laser beam to the surface of the magnetic response composite module and receives the reflected signal to calculate the displacement. The electromagnetic induction sensing unit senses the coupling state between the two by detecting changes in the magnetic field. The pressure trigger sensing unit is located on the contact surface of the programmable electromagnetic load stage module and collects pressure signals. Each unit converts the detection data into electrical signals and transmits them to the control, recording, and latching module.

4. The animal autonomous hindlimb muscle strength measurement system based on controllable magnetic load as described in claim 1, characterized in that, The control recording latch module includes: a synchronous trigger control unit, a current regulation output unit, a signal receiving and processing unit, and a parameter latch storage unit. The synchronous trigger control unit generates a synchronization signal and sends it to the behavior excitation and induction module and the current regulation output unit respectively. The current regulation output unit changes the power supply current of the programmable electromagnetic load module according to a preset program. The signal receiving and processing unit filters and amplifies the electrical signal transmitted by the sensing and judgment capture module. The parameter latch storage unit freezes the current current parameter and stores it in a designated storage area the instant it receives the trigger signal. The units interact with each other through an internal bus.

5. The animal autonomous hindlimb muscle strength measurement system based on controllable magnetic load as described in claim 1, characterized in that, The data conversion and processing module uses a muscle strength calculation model: ,in For the voluntary muscle strength of the animal's hind limbs, This is the latching current value. The permeability of free space, The number of turns of the electromagnet coil. The cross-sectional area of ​​the iron core is... The distance between the magnetic response unit and the platform. This is the angle correction factor. This represents the change in the angle of the animal's hind limbs during the push-off motion. Density of the magnetic response unit material. The instantaneous velocity during pedaling.

6. The animal autonomous hindlimb muscle strength measurement system based on controllable magnetic load as described in claim 1, characterized in that, The programmable electromagnetic load platform module adopts a magnetic field strength adjustment model: ,in The magnetic field strength, The permeability of free space, The number of coil turns. For supply current, The coil fill factor, The length of the air gap. The length of the iron core. The relative permeability of the iron core. For temperature coefficient, This represents the difference between the ambient temperature and the standard temperature.

7. The animal autonomous hindlimb muscle strength measurement system based on controllable magnetic load as described in claim 1, characterized in that, The magnetic response composite module adopts a coupled magnetic calculation model: ,in For coupling magnetic force, The magnetic field strength of the platform, Let be the cross-sectional area of ​​the permanent magnet. The permeability of free space, The angle between the magnetization direction of the permanent magnet and the direction of the magnetic field. The magnetization intensity of the permanent magnet. The magnetization intensity of the electromagnet core. This is the distance between the permanent magnet and the iron core.

8. The animal autonomous hindlimb muscle strength measurement system based on controllable magnetic load as described in claim 1, characterized in that, The behavior stimulation and induction module adopts a stimulus intensity adaptation model: ,in For stimulus intensity parameters, For species fitness coefficient, For the animal's weight, For the basic activity speed of animals, For the duration of stimulation, This is the environmental correction factor. This represents the difference between ambient brightness and standard brightness.

9. The animal autonomous hindlimb muscle strength measurement system based on controllable magnetic load as described in claim 1, characterized in that, The sensing and detection module adopts a separate decision-making model: ,in The threshold for separation determination, These are the initial position coordinates. For real-time location coordinates, For image acquisition frame rate, For standard frame rate, For speed correction factor, This represents the change in electromagnetically induced voltage.

10. A method for measuring the voluntary hindlimb muscle strength of animals based on controllable magnetic load, characterized in that, This method is applied to the animal autonomous hindlimb muscle strength measurement system based on controllable magnetic load as described in claim 1, and includes the following steps: S1, fixing the magnetic response composite module to the hindlimb of the animal to be tested using an adjustable restraint structure, so that the permanent magnet of the rigid base faces the contact surface of the programmable electromagnetic load stage module and maintains a preset initial distance; S2, positioning the animal torso using a flexible fixing mechanism, so that the hindlimb to be tested is in a naturally extended state and the contact surface of the magnetic response composite module is parallel to that of the programmable electromagnetic load stage module; S3, setting the initial current parameters, behavioral excitation mode, and sensing judgment threshold by controlling the recording latch module, and starting the system preheating program to allow each module to reach the required temperature. Stable working state; S4, the control recording latch module synchronously triggers the behavior stimulation and induction module and the programmable electromagnetic load stage module. The behavior stimulation and induction module outputs a preset stimulation signal, and the programmable electromagnetic load stage module generates a corresponding magnetic field according to the set current parameters; S5, the sensing judgment and capture module continuously collects position, displacement, magnetic field or pressure related data and transmits them to the control recording latch module. When the detected data reaches the set threshold, the control recording latch module immediately latches the current current parameters; S6, the data conversion and processing module calls the preset calibration database and the corresponding calculation model to convert the latched current parameters into the animal's hind limb voluntary muscle strength value and stores or outputs it according to the set format.

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