Quantitative evaluation method of mouse movement disorder based on movement counterforce test technology

Abstract

The application discloses a mouse movement disorder quantitative evaluation method based on a movement counterforce test technology, and comprises the following steps: S1, experiment table design and establishment; S2, sensor array calibration and parameter correction; S3, starting experiment; S4, repeating S3, performing N times of experiments, and saving test data; S5, constructing an Fz-t movement curve; S6, extracting single-step maximum movement counterforce Fmax; S7, determining whether Fmax of left movement and right movement has a significant difference, and if not, the mouse has no movement disorder; otherwise, entering S8; S8, calculating average values of Fmax of left movement and right movement, comparing smaller average values, and comparing with a reference range of average values of Fmax of corresponding sides of normal mice; if the average value is less than the minimum value in the reference range, the mouse has a movement disorder; otherwise, the mouse has no movement disorder. The application realizes quantitative collection of Z-direction force in the mouse movement process, and avoids problems of long time consumption and poor reliability of traditional behavior experiment and gait analysis technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of kinematics, in particular to a quantitative evaluation method for mouse movement disorders based on movement counterforce testing technology. BACKGROUND

[0002] Rodents, such as mice and rats, are commonly used as experimental animal models in biomedical research, particularly in the fields of neuroscience, sports medicine, and rehabilitation therapy. In order to gain a deeper understanding of the behavioral characteristics and gait patterns of these animals, researchers often need to use behavioral analysis methods and gait analysis techniques.

[0003] However, traditional behavioral analysis methods often only provide qualitative descriptions, lacking accurate quantitative evaluation. At the same time, traditional gait analysis methods, such as video-based analysis, while providing some quantitative information, are cumbersome and time-consuming to process, and are often affected by factors such as lighting conditions, video quality, etc., leading to inaccurate results.

[0004] For example: Beare J E, Morehouse J R, Devries W H, et al. Gait analysis in normal and spinal contused mice using the TreadScan system. [J]. Journal of Neurotrauma, 2009, 26(11): 2045-2056. DOI: 10.1089 / neu.2009.0914.

[0005] In this article, the TreadScan system was used to analyze the gait characteristics of mice with spinal cord injury models manufactured using transgenic technology, once a week, for a total of ten weeks. Disadvantages: the treadmill lane is short, the camera frame rate is limited, and the footprint automatic recognition needs to ensure that the bottom image is clear.

[0006] Miyagi M, Ishikawa T, Kamoda H, Orita S, Kuniyoshi K, Ochiai N, Kishida S, Nakamura J, Eguchi Y, Arai G, Suzuki M, Aoki Y, Toyone T, Takahashi K, Inoue G, Ohtori S. 2011. Assessment of gait in a rat model of myofascial inflammation using the CatWalk system. Spine 36: 1760-1764.

[0007] In this article, CatWalk system was used to analyze the gait of rats with myofascial inflammation, focusing on footprint analysis. Disadvantages: using fluorescence to highlight the footprint may result in incomplete display, and due to the long channel, the analysis time is relatively long, and some footprints need to be manually selected.

[0008] Wang J. CatWalk behavioral study of 6-hydroxydopamine-induced unilateral Parkinson's disease rats [D]. Southern Medical University, 2012.

[0009] CatWalk system was used to analyze various indicators of 6-OHDA Parkinson's disease model rats. Disadvantages: although the maximum contact area of the paw can be used as an effective parameter for analyzing Parkinson's disease rat models, it is too subjective to use it to reflect the support level, and lacks quantitative basis.

[0010] In recent years, with the development of technology, motion resistance testing technology has gradually become an important means of biomechanical research. This technology can accurately measure the ground reaction force generated by animals during walking, running and jumping, etc., so as to reflect their movement state and muscle activity. In addition, the development of high-speed camera system also makes it possible to accurately analyze animal gait. Through high-speed photography, every detail of animal movement can be captured, including the movement trajectory of limbs, posture change, etc., providing a rich data basis for gait analysis. SUMMARY

[0011] Therefore, the technical problem to be solved by the present application is to provide a quantitative evaluation method for mouse movement disorders based on motion resistance testing technology, which can overcome the problems of the traditional behavior analysis method for rodents that cannot give quantitative evaluation and the long time-consuming of gait analysis method.

[0012] The technical solution adopted is as follows:

[0013] A mouse movement disorder quantitative evaluation method based on a movement counterforce test technology, comprising the following steps:

[0014] S1, design and construction of an experimental table;

[0015] S2, calibrate the sensor array in the experimental table and complete parameter correction;

[0016] S3, start the mouse kinematics test experiment, collect the test data of the mouse in two consecutive gaits, and the test data includes video data and three-dimensional force data generated by the mouse on the specified motion channel in the experimental table on the stepped sensor;

[0017] S4, repeat S3, perform N experiments, and save the test data; save the test data including video data and three-dimensional force data collected by the sensor with Z force greater than zero, and the saved three-dimensional force data has the serial number of the sensor and the mark of the experiment number; normalize and filter the saved three-dimensional force data;

[0018] S5, for each sensor used in S3 and S4, according to the sampling rate of each sensor, add the corresponding time sequence to the saved three-dimensional force data, and construct the Fz-t movement curve of the mouse Z force and time sequence for each sensor;

[0019] S6, based on the Fz-t movement curve and the video data saved in S4, extract the maximum value of single-step Fz as the single-step maximum movement counterforce Fmax; specifically:

[0020] A gait cycle of a mouse is divided into left forelimb movement, left hindlimb movement, right forelimb movement and right hindlimb movement, based on the Fz-t movement curve, according to the video data saved in S4, two Fzmax1 values of the left forelimb movement of the mouse in two consecutive gaits, two Fzmax2 values of the left hindlimb movement, two Fzmax3 values of the right forelimb movement and two Fzmax4 values of the right hindlimb movement are obtained;

[0021] S7, the left forelimb movement and the left hindlimb movement of the mouse are attributed to the left movement, the right forelimb movement and the right hindlimb movement of the mouse are attributed to the right movement, and the Fmax of the left movement and the right movement are subjected to paired Student T test to determine whether there is a significant difference;

[0022] If the P value obtained by the Student T test is greater than 0.05, it is considered that the Fmax of the left movement and the right movement of the mouse has no statistical difference, and the mouse has no movement disorder; otherwise, go to S8;

[0023] S8, calculate the average of Fmax of the left movement and the average of Fmax of the right movement, compare the two averages, select the smaller average, and compare the smaller average with the reference range of the average of Fmax of the corresponding side of the normal mouse;

[0024] If less than the minimum value in the reference range, the mouse has movement disorder; otherwise, the mouse has no movement disorder.

[0025] The method of the application is based on the movement counterforce test technology, and a high-speed camera system is used to extract the gait and movement counterforce characteristics of animals simultaneously. The results obtained by using the method contain accurate three-dimensional movement counterforce data, and accurate time information and gait mode information can be obtained by transforming the collected results, and the obtained data is more objective. In actual application, the mouse movement disorder evaluation index obtained by a large amount of analysis and summary can effectively distinguish the movement disorder individuals and normal individuals, and provide more applications for the fields of sports medicine, rehabilitation treatment and the like.

[0026] Further preferably, the experimental table in S1 comprises a frame (1), a mechanical test system arranged on the frame (1), and a high-speed camera system arranged on the frame (1); the mechanical test system comprises a movement channel (5), a sensor array (2), and a data collector (3), the sensor array (2) is arranged on a movement platform (6), the movement platform (6) is arranged on the frame (1), the movement channel (5) is arranged on the movement platform (6) and located at the position of the sensor array (2), and the width of the movement channel (5) is adjustable; the data collector (3) is arranged on the frame (1), the sensor array (2) and the data collector (3) are in communication, the movement data collected by the sensor array (2) is sent into the data collector (3); the data collector (3) is electrically connected to an external computer, and the obtained movement data is sent into the external computer; the high-speed camera system comprises three high-speed cameras (4) and a video storage computer, the three high-speed cameras (4) are all arranged on the frame (1), the three high-speed cameras (4) are respectively located at both sides and the rear end of the sensor array (2), the three high-speed cameras (4) are all electrically connected to the video storage computer, the video storage computer is arranged on the frame (1), and the video storage computer is electrically connected to the external computer, and the obtained video data is sent into the external computer.

[0027] The experiment table has an adjustable-width movement channel, which ensures that the experiment table can adapt to test objects of different body sizes, and enhances the flexibility and practicality of the equipment; the experiment table combines a mechanical testing system and a high-speed camera system, can simultaneously perform mechanical data testing and video recording, and the real-time transmission of video data enables researchers to observe the experiment process in real time, thereby obtaining more comprehensive and accurate experimental data, greatly improving the experimental efficiency and ensuring data reliability; the high-speed camera system uses three high-speed cameras, which are respectively located on both sides and the rear end of the sensor array, can provide omnidirectional angle coverage, and thereby capture the movement of the test object in different directions.

[0028] Further preferably, the specific method of the mouse movement mechanics test experiment in S3 comprises the following steps:

[0029] S31, adjust the width of the movement channel to allow the mouse to walk straight along the movement channel, and fix the movement channel;

[0030] S32, keep the experimental environment quiet and low in brightness; start the mechanical testing system and the high-speed camera system respectively, detect whether the equipment is working normally, and start the experiment after confirming that the equipment is working normally;

[0031] S33, initialize the mechanical testing system and the high-speed camera system; after initialization, place the mouse at one end of the movement channel, guide it to enter the channel, and walk forward along the movement channel; until the mouse walks from one end of the movement channel to the other end; when the mouse enters the movement channel, the high-speed camera system and the mechanical testing system start recording video and force data respectively; when the mouse leaves the movement channel, the experiment ends, and the high-speed camera system and the mechanical testing system stop recording;

[0032] S34, repeat step S33 to obtain the test data of N experiments of the mouse.

[0033] The mouse movement mechanics test experiment uses the movement channel and the force array to test the ground movement reaction force of the mouse, quantitatively analyzes the movement of the mouse from the mechanical point of view, and measures the movement ability of different mice.

[0034] Further preferably, the sensor array (2) is composed of 24 three-dimensional force sensors arranged in a 3x8 manner; a force sheet for the mouse to tread on during movement is additionally installed above the vertical beam of each three-dimensional force sensor, the force sheet is installed on the movement platform (6), and each force sheet can move freely.

[0035] The three-dimensional force sensor array of the technical scheme is used for synchronously measuring the ground movement reaction force of each limb of a mouse, and a certain spacing is left between the force measuring pieces of the adjacent sensors in the array, so that the adjacent force measuring pieces will not collide under the full-scale force.

[0036] Further preferably, the movement channel (5) is composed of two acrylic plates, the two acrylic plates are vertically erected on the sensor array (2), and the two ends are fixed through support blocks, the support blocks are movably arranged on the movement platform (6); the movement channel (5) is formed between the two acrylic plates, and a space for movement of the force measuring piece is left between the two acrylic plates and the sensor array (2).

[0037] The movement channel of the technical scheme is made of transparent acrylic material, has good transparency and durability, has sufficient strength and stability, and can clearly observe the situation of the mouse in the channel; the two ends are fixed through the support blocks, which ensures the stability of the movement channel, allows the channel to remain fixed or be adjusted during the experiment, and increases the flexibility of the experiment; the space left between the movement channel and the sensor array ensures that the movement channel will not affect the data measurement of the force measuring array, and ensures the accuracy of the data.

[0038] Further preferably, the sensor calibration in the experiment table in S2 includes static calibration of the three-dimensional force sensor and dynamic calibration of the three-dimensional force sensor.

[0039] The method for static calibration of the three-dimensional force sensor is that a group of known constant loads are applied to each three-dimensional force sensor in X, Y and Z directions, the static characteristic curve of the sensor bridge is obtained through calibration, so as to obtain the decoupling matrix [C], the decoupling matrix [C] is input into the acquisition program, and the static calibration is completed.

[0040] The method for dynamic calibration of the three-dimensional force sensor adopts the step response method, a known and constant force is applied to each direction of the three-dimensional force sensor, then the force is removed, the output signal of the three-dimensional force sensor is obtained, and the output signal is subjected to frequency spectrum analysis to obtain the natural frequency.

[0041] The purpose of static calibration of the sensor array in the technical scheme is to establish a corresponding relationship between the force and the voltage through the static calibration process of the strain sensor, which is an important link for normal use of the sensor, a corresponding voltage is obtained by loading a known weight, and in the test process, the voltage generated by loading an unknown force can be converted into a mechanical quantity through the decoupling matrix, and the sensitivity and other indexes of the sensor can also be obtained through calibration.

[0042] The purpose of the dynamic calibration of the sensor array in the technical scheme of the present application is that, in the process of measuring dynamic force, only static calibration of the sensor is not enough, because a sensor with good performance under static test conditions may have great distortion under dynamic conditions, and even cannot work. Therefore, the sensor must be dynamically calibrated to test its normal working frequency range.

[0043] Further preferably, in the technical scheme of the present application, the parameter correction method of the sensor in the experimental table in S2 is as follows: through the calibration process, a plurality of static characteristic curves of the sensor bridge can be obtained, the static characteristic curves are fitted into a straight line through the least square method, the slope k of the straight line is obtained, and thus the decoupling matrix [C] is obtained, the calibration operation of each sensor in the 3*8 force array is performed, and thus 24 decoupling matrices are obtained, which are input into the back end of the acquisition program of LabView, and the parameter correction is completed.

[0044] In summary, the technical scheme of the present application, the parameter correction purpose of the sensor in the experimental table is to improve the accuracy and reliability of the experimental data, to correct the errors of the sensor through calibration, to improve the accuracy and reliability of the data, to simplify the calibration process through fitting into a straight line by the least square method, and to improve the operation efficiency through batch processing of calibration of a plurality of sensors.

[0045] The present application has the following beneficial effects:

[0046] 1. The method of the present application realizes quantitative collection of Z-direction force in the movement of a mouse through a three-dimensional force sensor force array, and avoids the problems of long time consumption and poor reliability in traditional behavior experiment and gait analysis technology.

[0047] 2. The method of the present application can realize synchronous display of video and image through synchronous work of the three-dimensional force sensor force array and the high-speed camera system, and improves the intuitiveness of display.

[0048] 3. The method of the present application is also applicable to promotion to analysis of kinematic parameters in other similar situations, such as geckos, tree frogs, athletes, etc., and can effectively improve the analysis efficiency and reduce the cost. DETAILED DESCRIPTION

[0049] Figure 1 The flowchart of the method of the present application is shown in the figure;

[0050] Figure 2 The structure schematic diagram of the experimental table of the present embodiment is shown in the figure;

[0051] Figure 3 The part drawing of the acrylic plate on the experimental table of the present embodiment is shown in the figure;

[0052] Figure 4 Wheatstone bridge schematic diagram;

[0053] Figure 5 Schematic diagram of a single three-dimensional force sensor in the embodiment;

[0054] Figure 6 Schematic diagram of X-direction static calibration of a single three-dimensional force sensor in the embodiment;

[0055] Figure 7 Schematic diagram of Y-direction static calibration of a single three-dimensional force sensor in the embodiment;

[0056] Figure 8 Schematic diagram of Z-direction static calibration of a single three-dimensional force sensor in the embodiment;

[0057] Figure 9 Schematic diagram of X-direction dynamic calibration of a single three-dimensional force sensor in the embodiment;

[0058] Figure 10 Schematic diagram of Y-direction dynamic calibration of a single three-dimensional force sensor in the embodiment;

[0059] Figure 11 Schematic diagram of Z-direction dynamic calibration of a single three-dimensional force sensor in the embodiment;

[0060] Figure 12 Calibration result curve of X-direction of a single three-dimensional force sensor in the embodiment;

[0061] Figure 13 Calibration result curve of Y-direction of a single three-dimensional force sensor in the embodiment;

[0062] Figure 14 Calibration result curve of Z-direction of a single three-dimensional force sensor in the embodiment;

[0063] Figure 15 Fz-t curve of a single sensor;

[0064] Figure legend: 1-frame, 2-sensor array, 3-data collector, 4-high-speed camera, 5-motion channel, 51-gap, 6-motion platform. DETAILED DESCRIPTION

[0065] The technical solutions of the present application will be described in detail below, but the protection scope of the present application is not limited to the described embodiments.

[0066] In order to make the purpose, technical solutions and advantages of the present application more clear, the following will combine the attached drawings to make a detailed description. Figures 1-5The application will be further described in detail with reference to the embodiments. It should be understood that the specific embodiments described herein are merely intended to explain the application and are not intended to limit the application.

[0067] As shown in the embodiments, the application is a quantitative evaluation method for mouse movement disorder based on movement counterforce test technology, comprising the following steps: Figure 1

[0068] S1, design and build the experimental table;

[0069] S2, calibrate the sensor array in the experimental table and complete parameter correction;

[0070] S3, start the mouse kinematics test experiment, collect the test data of the mouse in two consecutive gaits, and the test data includes video data and three-dimensional force data generated by the mouse on the specified movement channel in the experimental table;

[0071] S4, repeat S3 for N times of experiments and save the test data; the saved test data includes video data and three-dimensional force data with Z-direction force greater than zero collected by the sensor, the saved three-dimensional force data is marked with the serial number of the sensor and the number of experiments; normalize and filter the saved three-dimensional force data;

[0072] S5, for each sensor used in S3 and S4, add the corresponding time sequence to the saved three-dimensional force data according to the sampling rate of each sensor, and construct the Fz-t movement curve of the Z-direction force of the mouse and the time sequence for each sensor;

[0073] S6, based on the Fz-t movement curve and the video data saved in S4, extract the maximum value of single-step Fz as the maximum movement counterforce Fmax; specifically:

[0074] One gait cycle of the mouse is divided into left forelimb movement, left hindlimb movement, right forelimb movement and right hindlimb movement, based on the Fz-t movement curve, according to the video data saved in S4, two Fzmax1 values of the left forelimb movement of the mouse in two consecutive gaits, two Fzmax2 values of the left hindlimb movement, two Fzmax3 values of the right forelimb movement and two Fzmax4 values of the right hindlimb movement are obtained;

[0075] S7, the left forelimb movement and the left hindlimb movement of the mouse are attributed to left movement, the right forelimb movement and the right hindlimb movement of the mouse are attributed to right movement, and the Fmax of the left movement and the right movement are subjected to paired Student T test to determine whether there is a significant difference;

[0076] ​If the P value obtained by the Student T test is greater than 0.05, it is considered that the Fmax of the left movement and the Fmax of the right movement of the mouse have no statistical difference, and the mouse has no movement disorder; otherwise, S8 is entered;

[0077] S8, the average value of the Fmax of the left movement and the average value of the Fmax of the right movement are calculated, the two average values are compared, the smaller average value is selected, and the smaller average value is compared with the reference range of the average value of the corresponding side of the normal mouse Fmax;

[0078] If it is less than the minimum value in the reference range, the mouse has movement disorder; otherwise, the mouse has no movement disorder.

[0079] As shown in Figure 2 , in S1, the specific process of designing and building the experimental table is that the experimental table in S1 includes a frame 1, a mechanical testing system arranged on the frame 1, and a high-speed camera system arranged on the frame 1.

[0080] The frame 1 of the embodiment serves to fix the mechanical testing system and the high-speed camera system; the frame 1 is made of aluminum profile.

[0081] The mechanical testing system in the embodiment includes a movement channel 5, a sensor array 2, and a data collector 3, the sensor array 2 is arranged on a movement platform 6, in the embodiment, the sensor array 2 is composed of 24 three-dimensional force sensors arranged in a 3×8 manner; a force plate for the mouse to tread during movement is additionally arranged above the vertical beam of each three-dimensional force sensor, the 24 three-dimensional force sensors are fixed in the grooves pre-processed on the movement platform 6, the force plate is attached to the vertical beam of each three-dimensional force sensor, and the force plate is located at the groove opening of the groove on the movement platform 6, and after all the force plates are attached, they are coplanar with the upper surface of the movement platform 6. After the force plates are attached, the movement between the force plates is ensured.

[0082] The movement platform 6 is high on the frame 1, and can be achieved by bolts or other fixing methods. The movement platform 6 of the embodiment is made of metal material on the side, which can provide good protection for the internal three-dimensional force sensors, and the upper cover plate is made of light acrylic plate, which is pre-opened with grooves of the same shape as the force plates.

[0083] The movement channel 5 is arranged on the movement platform 6 and located at the position of the sensor array 2, and the width of the movement channel 5 is adjustable.

[0084] As shown in Figure 2 and 3As shown, in the embodiment, the movement channel 5 is composed of two pieces of acrylic plate, which are vertically erected on the sensor array 2 and fixed by the support block at both ends, and the support block is movably arranged on the upper surface of the movement platform 6; the movement channel 5 is formed between the two pieces of acrylic plate. There is a space for the force plate to move between the two pieces of acrylic plate and the sensor array 2, specifically, a notch 51 is formed on the two pieces of acrylic plate to form the space, when the mouse steps on the force plate, the force plate will tilt, and the space is used to accommodate the tilt of the force plate.

[0085] In the embodiment, according to the movement characteristics of the mouse, the movement direction of the mouse is determined, and the movement range of the mouse is limited by the movement channel 5 with front and rear openings and adjustable width without contacting the mechanical testing system. The channel width of the movement channel 5 is adjusted by loosening the support block, moving the two pieces of acrylic plate outward or inward, and increasing or decreasing the distance between the two pieces of acrylic plate.

[0086] As shown, Figure 2 the data collector 3 is bolted to the frame 1 and located below the movement platform 6 for convenient wiring. The sensor array 2 communicates with the data collector 3, and the movement data collected by the sensor array 2 is sent to the data collector 3; the data collector 3 is electrically connected to the external computer, and the obtained movement data is sent to the external computer.

[0087] In the embodiment, the sensor array 2 is composed of 24 three-dimensional force sensors arranged in a 3x8 manner; a force plate for the mouse to step on during movement is installed above the vertical beam of each three-dimensional force sensor, and the force plates are installed on the movement platform 6 and can freely move between each other.

[0088] In the embodiment, during the test, considering the possibility of the mouse excreting on the sensor, in order to prevent damage to the equipment, a layer of soft film needs to be covered on the sensor array 2 before the experiment to protect the sensor from being damaged without affecting the force.

[0089] In the embodiment, the data collector 3 is a known product in the technical field, which is known to those skilled in the art.

[0090] As shown, Figure 2 the high-speed camera system of the embodiment includes three high-speed cameras 4 and a video storage computer, and the three high-speed cameras 4 are fixed on the frame 1, and the three high-speed cameras 4 are located at both sides and the rear end of the sensor array 2, specifically: the three high-speed cameras are fixed at both sides and the obliquely upper 45° position of the sensor array 2, the camera at the obliquely upper position faces the movement channel entrance, ensures that the sensor array 2 is located in the shooting range, and can clearly shoot the left and right sides and the rear side of the mouse.

[0091] Three high-speed cameras 4 are electrically connected with a video storage computer, which is arranged on the frame 1 and is electrically connected with an external computer to send the obtained video data to the external computer.

[0092] In the embodiment, S2, the sensor calibration in the experiment table includes static calibration of the three-dimensional force sensor and dynamic calibration of the three-dimensional force sensor.

[0093] The method for static calibration of the three-dimensional force sensor is that a group of known constant loads are applied to each three-dimensional force sensor in X, Y and Z directions, the static characteristic curve of the sensor bridge is obtained through calibration, so as to obtain the decoupling matrix [C], and the decoupling matrix [C] is input into the collection program, so as to complete the static calibration. Specifically,

[0094] First, the three-dimensional force sensor is statically calibrated. The static calibration of each three-dimensional force sensor is to obtain the coefficient decoupling matrix [C] by decoupling algorithm from the known force vector [F] and the bridge output voltage UO. Considering the patch error during processing of the three-dimensional force sensor and the actual use scene, such as Figure 4 As shown in the figure, the relationship between the bridge output voltage and the force should be:

[0095]

[0096] The physical meaning of the output value C xx in the coefficient decoupling matrix [C] is that the bridge output voltage in the X direction is added to the unit load force in the X direction; the physical meaning of C xy is that the bridge output voltage in the X direction is added to the unit load force in the Y direction; the physical meaning of C xz is that the bridge output voltage in the X direction is added to the unit load force in the Z direction; the physical meaning of C yx is that the bridge output voltage in the Y direction is added to the unit load force in the X direction; the physical meaning of C yy is that the bridge output voltage in the Y direction is added to the unit load force in the Y direction; the physical meaning of C yz is that the bridge output voltage in the Y direction is added to the unit load force in the Z direction; the physical meaning of C zx is that the bridge output voltage in the Z direction is added to the unit load force in the X direction; the physical meaning of C zy is that the bridge output voltage in the Z direction is added to the unit load force in the Y direction; the physical meaning of C zz is that the bridge output voltage in the Z direction is added to the unit load force in the Z direction; F X , F y , F z are force loads in X, Y and Z directions respectively; U X , U y , U z, respectively, are the bridge output voltage values in X, Y, Z directions after the force vector [F] is applied to the three-dimensional force sensor.

[0097] The force vector [F] is known and constant, and in this embodiment, it is replaced by a set of known weights.

[0098] In this embodiment, based on the sensor array 2 composed of 24 three-dimensional force sensors arranged in a 3x8 manner, when static calibration is performed, the sensor bridge static characteristic curve is obtained by calibration, thereby obtaining the coefficient decoupling matrix [C], and the above operation is performed on each sensor in the 3x8 sensor, that is, 24 coefficient decoupling matrices are obtained, and the 24 coefficient decoupling matrices [C] are input into the acquisition program, thereby completing the static calibration.

[0099] For example:

[0100] The rotation applies a set of known constant loads in the X, Y, Z directions of a single three-dimensional force sensor. As a result, each three-dimensional force sensor has a patch position in each of the three directions, such as Figure 5 A, B, and C in FIG. 1, each of which is attached with a set of metal strain gauges for measuring three components Fx, Fy, and Fz of the measured force. The strain gauges form a Wheatstone full-bridge circuit, as shown in Figure 4 , which ensures the accuracy requirements of the sensor.

[0101] The output voltage values of the three bridges must be recorded each time the load is applied. By calibration, 9 sensor bridge static characteristic curves (three sets of bridge output voltage static characteristic curves when loading in the Fx direction; three sets of bridge output voltage static characteristic curves when loading in the Fy direction; and three sets of bridge output voltage static characteristic curves when loading in the Fz direction) are obtained, and the static characteristic curve is fitted into a straight line by the least squares method. The equation of the straight line is converted into the form y=kx+b. The slope k of the straight line corresponds to one of the 9 coefficients in the decoupling matrix. The decoupling matrix is obtained, and the inverse of the matrix is obtained, thereby obtaining the related sensitivity coefficient matrix. In actual testing, the vector [F] can be obtained from the collected bridge output voltage vector [U], and the calibration work can be completed.

[0102] According to the calibration result curve, the decoupling matrix C is obtained as follows:

[0103]

[0104] As shown in Figure 12 , 13 and 14, the following is obtained:

[0105]

[0106] The method for dynamic calibration of the three-dimensional force sensor adopts a step response method, a known and constant force is applied in each direction of the three-dimensional force sensor, then the force is removed, the output signal of the three-dimensional force sensor is obtained, and the natural frequency is obtained by performing frequency spectrum analysis on the output signal. Specifically,

[0107] A known and constant force is applied in each direction of the three-dimensional force sensor, in the embodiment, a mass block is bound by a wire, then the wire is instantaneously burned off by a flame to obtain the output signal of the sensor. The output signal is subjected to frequency spectrum analysis to obtain the natural frequency thereof, and the experimental requirements are determined. The force array is subjected to parameter correction according to the decoupling matrix and the natural frequency.

[0108] The specific method of the mouse kinematics test experiment in the embodiment S3 includes the following steps.

[0109] S31, adjusting the width of the movement channel for the mouse to walk straight along the movement channel, and fixing the movement channel;

[0110] S32, keeping the experimental environment quiet and the brightness low, starting the kinematics test system and the high-speed camera system respectively, detecting whether the equipment is working normally, and starting the experiment after confirming that the equipment is working normally;

[0111] S33, initializing the kinematics test system and the high-speed camera system; after initialization, the mouse is placed at one end of the movement channel, and guided to enter the channel and walk forward along the movement channel; until the mouse walks from one end of the movement channel to the other end of the movement channel; the high-speed camera system and the kinematics test system start recording video and recording force data respectively when the mouse enters the movement channel; the experiment ends when the mouse leaves the movement channel, and the high-speed camera system and the kinematics test system stop recording;

[0112] S34, repeating step S33 to obtain the test data of N experiments of the mouse.

[0113] In step S33 of the embodiment, the mouse is placed at one end of the movement channel, guided to enter the channel, and food is placed at the other end of the acrylic channel to lure the mouse to walk forward. The high-speed camera system and the kinematics test system record video and record three-dimensional force data respectively when the mouse enters the movement channel, and stop recording video and recording data when the mouse leaves the channel. Each experiment obtains three videos and an array [F0] storing three-dimensional force data of 24 sensors, with a size of , representing the number of sampling points of each experiment.

[0114] In this embodiment, the sensor array contains 24 sensors, each of which contains force data in X, Y, Z directions, so the force data array [F0] obtained after each experiment has 72 columns.

[0115] In this embodiment, the test data of N experiments on mice is saved, only the three-dimensional force data of the three-dimensional force sensor with Z direction force greater than zero is saved, and the force data of the rest of the three-dimensional force sensor is not saved.

[0116] Individuals with movement disorders may have less muscle strength than normal individuals, and may have difficulty supporting their body weight. The force in the Z direction is usually related to the vertical movement and support. When the individual supports his body weight, the reaction force of the ground on the limb will have an upward component on the Z axis, so the force in the Z direction can intuitively reflect the support level of the mouse limb. By monitoring the change of the limb support level, the muscle strength of the specific limb can be effectively evaluated, and the movement ability is reflected.

[0117] Further, the three-dimensional force data collected by the three-dimensional force sensor is in txt format, which contains a flag bit and force data in the Z direction. The number of rows of the original data is accurate to the measurement time.

[0118] In this embodiment S4, the saved test data includes video data and three-dimensional force data collected by the sensor with Z direction force greater than zero. The saved three-dimensional force data has the serial number of the sensor and the mark of the number of experiments.

[0119] The saved three-dimensional force data is normalized and filtered. The normalization of the three-dimensional force data eliminates the influence of body weight. On this basis, the frequency spectrum analysis of the force signal in each direction is carried out to obtain its natural frequency. According to the frequency characteristics, the influence of noise is excluded by filtering.

[0120] In the processing process, the sampling frequency of the sensor has been set to 1000Hz. First, the count is replaced with a time sequence according to the sampling rate, and all force data is normalized to convert it to data between [0, 1] to exclude the influence of body weight. On this basis, the Z direction force signal is subjected to fft transform using MATLAB, which can obtain a part of high frequency noise signal in the Z direction in addition to the low frequency signal less than 50Hz. According to this result, the Z direction force signal is subjected to low pass filter processing using butter filter to eliminate the influence of high frequency noise.

[0121] Finally, the processed three-dimensional force data is saved according to the sensor number respectively, which is used to construct the Fz-t movement curve of the Z direction force of the mouse and the time sequence for each sensor in this embodiment S5.

[0122] In this embodiment S7, the paired Student T test mentioned is a known technique.

[0123] In this embodiment S8, the reference range of the average Fmax of the corresponding side of the normal mouse is calculated by using the experimental bench and the method of steps S1-S6 described in this embodiment method on several normal mice in advance, and the reference range of the Z-direction force of the normal mouse is determined in the form of average ± standard deviation.

[0124] Application examples

[0125] Take a mouse as an example as follows:

[0126] The embodiment in the application takes a mouse as an example, including the following steps:

[0127] S1, design and build an experimental bench;

[0128] S2, calibrate the sensor array in the experimental bench and complete parameter correction;

[0129] S3, start the mouse kinematics test experiment, collect the test data of the mouse in two consecutive gaits, and the test data includes video data and three-dimensional force data generated by the mouse on the specified motion channel in the experimental bench on the stepped sensor;

[0130] S4, repeat S3 for N times of experiments, and save the test data; the saved test data includes video data and three-dimensional force data with Z-direction force greater than zero collected by the sensor, and the saved three-dimensional force data is marked with the serial number of the sensor and the number of experiments; normalize and filter the saved three-dimensional force data;

[0131] S5, for each sensor used in S3 and S4, add the corresponding time sequence to the saved three-dimensional force data according to the sampling rate of each sensor, and construct the Fz-t motion curve of the Z-direction force of the mouse and the time sequence for each sensor;

[0132] S6, based on the Fz-t motion curve and the video data saved in S4, extract the maximum value of single-step Fz as the maximum single-step motion reaction force Fmax; specifically:

[0133] A gait cycle of a mouse is divided into left forelimb movement, left hindlimb movement, right forelimb movement and right hindlimb movement, based on the Fz-t motion curve, according to the video data saved in S4, two Fzmax1 values of the left forelimb movement of the mouse in two consecutive gaits, two Fzmax2 values of the left hindlimb movement, two Fzmax3 values of the right forelimb movement and two Fzmax4 values of the right hindlimb movement are obtained in N times of experiments;

[0134] S7. Assign the left forelimb and left hindlimb movements of the mouse to the left side of the movement, and the right forelimb and right hindlimb movements to the right side of the movement. Perform a pairwise Student T test on the Fmax of the left and right side movements to determine whether there is a significant difference.

[0135] If the P-value obtained from the Student T-test is greater than 0.05, it is considered that there is no statistically significant difference in Fmax between the left and right sides of the mouse, and the mouse has no motor impairment; otherwise, proceed to S8.

[0136] S8. Calculate the average value of Fmax for left-side movement and the average value of Fmax for right-side movement. Compare the two average values ​​and select the smaller average value. Compare the smaller average value with the reference range of the average Fmax value for the corresponding side of a normal mouse.

[0137] If the value is less than the minimum value within the reference range, the mouse has motor impairment; otherwise, the mouse does not have motor impairment.

[0138] In one specific embodiment, the experimental platform in S1 includes a frame, a mechanical testing system, and a high-speed camera system. The frame, made of aluminum profile, is used to fix the mechanical testing system and the camera system. The mechanical testing system includes a motion channel, a sensor array, and a data acquisition unit. The sensor array consists of 24 three-dimensional force sensors, fixed in pre-machined grooves on the motion platform. Force plates are mounted on the vertical beams of each sensor, located at the groove openings for the mouse to step on. The motion channel consists of two adjustable-width acrylic plates, restricting the mouse's range of motion. The data acquisition unit is fixed to the frame, connected to the sensor array and an external computer, and collects force data during movement. The high-speed camera system includes three high-speed cameras, fixed to the frame, located on both sides and above the sensor array, respectively, and connected to a video storage computer to record the mouse's movement. A soft protective film covers the sensor array.

[0139] In one specific embodiment, the calibration and parameter correction process of the sensor array in S2 includes:

[0140] like Figure 6 , 7 As shown in Figures 8, 9, 10, and 11, the method for static calibration of a three-dimensional force sensor is as follows: a set of known constant loads are applied to each three-dimensional force sensor in the X, Y, and Z directions. The static characteristic curve of the sensor bridge is obtained through calibration, thereby obtaining the coefficient decoupling matrix [C]. The decoupling matrix [C] is input into the acquisition program, thus completing the static calibration. The method for dynamic calibration of a three-dimensional force sensor adopts the step response method. A known and constant force is applied to each direction of the three-dimensional force sensor, and then the force is removed to obtain the output signal of the three-dimensional force sensor. The natural frequency is obtained by performing spectrum analysis on the output signal.

[0141] The parameter correction method of the sensor is: through the calibration process, a plurality of static characteristic curves of the sensor bridge circuit can be obtained, the static characteristic curves are fitted into a straight line by the least square method, the slope k of the straight line is obtained, and then the decoupling matrix [C] is obtained. The calibration operation is performed on each sensor in the 3*8 force array, 24 decoupling matrices are obtained, and the decoupling matrices are input into the back end of the acquisition program of LabView, and the parameter correction is completed.

[0142] In one specific embodiment, the specific process of the mouse kinematics test experiment in S3 is as follows:

[0143] First, the data of normal mice is collected. A group of normal mice (3 in number) are made to move along the channel on the experimental table, and the test data of each mouse in two consecutive gaits are collected, including video data and three-dimensional force data. The experiment is repeated 7 times for each normal mouse, the test data is saved and normalized and filtered, and the Fz-t motion curve of the Z-direction force of each sensor of the normal mouse in each experiment is constructed. The Fzmax value of the normal mouse in two consecutive gaits is extracted from the Fz-t motion curve and the video data, which is the Fzmax value of the left front leg, the left hind leg, the right front leg and the right hind leg, respectively.

[0144] The Fzmax data of the normal mouse is statistically analyzed, and the Fmax average value and the standard deviation of the left side (left front leg and left hind leg) and the right side (right front leg and right hind leg) are calculated, respectively, to obtain the following data: left side: 0.541±0.068; right side: 0.531±0.076, so as to determine the reference range of the normal mouse left and right motion reaction: left reference range [0.473, 0.609]; right reference range [0.455, 0.607].

[0145] The same experimental table is used to test a mouse which is not confirmed whether it has movement disorder. The specific steps include the following: adjust the width of the movement channel to only allow the mouse to walk straight along the movement channel, and fix the movement channel; keep the experimental environment quiet and the brightness low; start the mechanics test system and the high-speed camera system respectively, detect whether the equipment is working normally, and confirm that the equipment is working normally before starting the experiment;

[0146] After the experiment starts, the mechanics test system and the high-speed camera system are initialized; after the initialization is completed, the mouse is placed at one end of the movement channel and guided to enter the channel and walk forward along the movement channel; until the mouse walks from one end of the movement channel to the other end of the movement channel; the high-speed camera system and the mechanics test system start recording video and force data respectively when the mouse enters the movement channel is observed by the high-speed camera system; when the mouse leaves the movement channel, the experiment is ended, and the high-speed camera system and the mechanics test system stop recording;

[0147] In one embodiment, the test step of S3 is repeated in S4 to obtain the test data of N experiments of the mouse. The saved test data includes video data and three-dimensional force data collected by the sensor when the Z-direction force is greater than zero, and the saved three-dimensional force data is marked with the serial number of the sensor and the number of the experiment; the saved three-dimensional force data is normalized and filtered.

[0148] In one embodiment, the process of constructing the F-t motion curve in S5 is as follows: according to each sensor used in the experiment, according to the sampling rate of the sensor, the saved three-dimensional force data is added with the corresponding time sequence, and the Fz-t motion curve of the Z-direction force of the mouse and the time sequence is constructed for each sensor. As shown in Figure 15 .

[0149] In one embodiment, the process of extracting the maximum value of single-step Fz in S6 is as follows: one gait cycle of the mouse is divided into left forelimb movement, left hindlimb movement, right forelimb movement and right hindlimb movement, based on the Fz-t motion curve, according to the video data saved in S4, two Fzmax1 values of the left forelimb movement, two Fzmax2 values of the left hindlimb movement, two Fzmax3 values of the right forelimb movement and two Fzmax4 values of the right hindlimb movement of the mouse in two consecutive gaits are obtained in 7 experiments; after 7 experiments on one mouse, a total of 14 Fzmax1 values of the left forelimb movement, 14 Fzmax2 values of the left hindlimb movement, 14 Fzmax3 values of the right forelimb movement and 14 Fzmax4 values of the right hindlimb movement can be obtained.

[0150] In one embodiment, the process of comparing the left and right motion reaction force data in S7 is as follows: the left forelimb movement and the left hindlimb movement of the mouse are attributed to the left movement, the right forelimb movement and the right hindlimb movement of the mouse are attributed to the right movement, the Fmax of the left movement and the right movement are subjected to paired Student T test to determine whether there is a significant difference;

[0151] The P value of the mouse obtained by Student T test is 5.6913x10 -8 , less than 0.05, entering S8.

[0152] In one embodiment, the process of comparing with the reference range in S8 is as follows: the average value of the Fmax of the left movement and the average value of the Fmax of the right movement are calculated, the two average values are compared, the smaller average value is selected, and the smaller average value is compared with the reference range of the average value of the Fmax of the corresponding side of the normal mouse;

[0153] The average of the left Fmax of the mouse is 0.466, and the average of the right Fmax is 0.543. The average of the left Fmax is less than the average of the right Fmax. Therefore, the average of the left Fmax of the mouse is compared with the reference range of the left Fmax of the normal mouse. The average of the left Fmax of the mouse is 0.466, which is less than the minimum value 0.473 of the reference range of the left Fmax of the normal mouse. Therefore, it is judged that the mouse has movement disorder.

[0154] The above examples only illustrate the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the present application.

Claims

1. A quantitative evaluation method for movement disorders in mice based on motion reaction force testing technology, characterized in that: Includes the following steps: S1. Design and construction of the experimental platform; S2. Calibrate the sensor array in the experimental setup and complete parameter correction; S3. Begin the biomechanics test experiment on mice, and collect test data of mice in two consecutive gaits. The test data includes video data and three-dimensional force data generated by the mice on the stepping sensors in the designated movement channel in the experimental table. S4. Repeat S3 for N experiments and save the test data. The saved test data includes video data and three-dimensional force data with a Z-axis force greater than zero collected by the sensor. The saved three-dimensional force data includes the sensor number and the number of experiments. Normalize and filter the saved three-dimensional force data. S5. For each sensor used in S3 and S4, add the corresponding time series to the saved three-dimensional force data according to the sampling rate of each sensor, and construct the Fz-t motion curve of the mouse's Z-axis force versus time series for each sensor. S6. Based on the Fz-t motion curve and the video data saved in S4, extract the maximum value of Fz for a single step as the maximum reaction force Fmax for a single step; specifically: A mouse gait cycle is divided into left forelimb movement, left hindlimb movement, right forelimb movement, and right hindlimb movement. Based on the Fz-t movement curve, according to the video data saved in S4, the two Fzmax1 values ​​of the left forelimb movement, the two Fzmax2 values ​​of the left hindlimb movement, the two Fzmax3 values ​​of the right forelimb movement, and the two Fzmax4 values ​​of the right hindlimb movement are obtained for the mouse in two consecutive gaits in N experiments. S7. Assign the left forelimb and left hindlimb movements of the mouse to the left side of the movement, and the right forelimb and right hindlimb movements to the right side of the movement. Perform a pairwise Student T test on the Fmax of the left and right side movements to determine whether there is a significant difference. If the P-value obtained from the Student T-test is greater than 0.05, it is considered that there is no statistically significant difference in Fmax between the left and right sides of the mouse, and the mouse has no motor impairment; otherwise, proceed to S8. S8. Calculate the average value of Fmax for left-side movement and the average value of Fmax for right-side movement. Compare the two average values ​​and select the smaller average value. Compare the smaller average value with the reference range of the average Fmax value for the corresponding side of a normal mouse. If the value is less than the minimum value within the reference range, the mouse has motor impairment; otherwise, the mouse does not have motor impairment.

2. The method for quantitative evaluation of mouse movement disorders based on motion reaction force testing technology according to claim 1, characterized in that, The experimental platform in S1 includes a frame (1), a mechanical testing system mounted on the frame (1), and a high-speed camera system mounted on the frame (1); The mechanical testing system includes a motion channel (5), a sensor array (2), and a data acquisition unit (3). The sensor array (2) is arranged on a motion platform (6), which is set on a frame (1). The motion channel (5) is set on the motion platform (6) and located at the location of the sensor array (2). The width of the motion channel (5) is adjustable. The data acquisition unit (3) is set on the frame (1). The sensor array (2) communicates with the data acquisition unit (3). The motion data collected by the sensor array (2) is sent into the data acquisition unit (3). The data acquisition unit (3) is electrically connected to an external computer and sends the obtained motion data to the external computer. The high-speed camera system includes three high-speed cameras (4) and a video storage computer. The three high-speed cameras (4) are all mounted on the frame (1). The three high-speed cameras (4) are located on both sides and the rear end of the sensor array (2). The three high-speed cameras (4) are all electrically connected to the video storage computer. The video storage computer is mounted on the frame (1) and electrically connected to an external computer to send the obtained video data to the external computer.

3. The method for quantitative evaluation of mouse movement disorders based on motion reaction force testing technology according to claim 2, characterized in that, The specific methods for the mouse biomechanics testing experiment in S3 include the following steps: S31. Adjust the width of the movement channel to allow the mouse to walk in a straight line along the movement channel, and fix the movement channel; S32. Keep the experimental environment quiet and reduce the brightness; start the mechanical testing system and high-speed camera system respectively to check whether the equipment is working properly. After confirming that the equipment is working properly, start the experiment. S33. Initialize the mechanical testing system and high-speed camera system; after initialization, place the mouse at one end of the movement channel and guide it into the channel, and let it walk forward along the movement channel; until it walks from one end of the movement channel to the other end; when the mouse enters the movement channel, the high-speed camera system and the mechanical testing system start recording video and force data respectively; when the mouse leaves the movement channel, the experiment ends, and the high-speed camera system and the mechanical testing system stop recording; S34. Repeat step S33 to obtain test data for N experiments on the mouse.

4. The method for quantitative evaluation of mouse movement disorders based on motion reaction force testing technology according to claim 2, characterized in that, The sensor array (2) consists of 24 three-dimensional force sensors arranged in a 3×8 manner; a force measuring plate is installed above the vertical beam of each three-dimensional force sensor for the mouse to step on during the movement. The force measuring plate is installed on the movement platform (6) and the force measuring plates can move freely between each other.

5. The method for quantitative evaluation of mouse movement disorders based on motion reaction force testing technology according to claim 4, characterized in that, The motion channel (5) is composed of two acrylic plates. The two acrylic plates stand vertically on the sensor array (2) and are fixed at both ends by support blocks. The support blocks are movably set on the motion platform (6). The motion channel (5) is formed between the two acrylic plates, and there is space for the force measuring plate to move between the two acrylic plates and the sensor array (2).

6. The method for quantitative evaluation of mouse movement disorders based on motion reaction force testing technology according to claim 2, characterized in that, The sensor calibration in the experimental platform of S2 includes static calibration of the three-dimensional force sensor and dynamic calibration of the three-dimensional force sensor; The method for static calibration of three-dimensional force sensors is as follows: a set of known fixed loads are applied to each three-dimensional force sensor in the X, Y, and Z directions. The static characteristic curve of the sensor bridge is obtained through calibration, thereby obtaining the coefficient decoupling matrix [C]. The decoupling matrix [C] is input into the acquisition program, thus completing the static calibration. The step response method is used to dynamically calibrate the three-dimensional force sensor. A known and constant force is applied in each direction of the three-dimensional force sensor, and then the force is removed to obtain the output signal of the three-dimensional force sensor. The natural frequency is obtained by performing spectrum analysis on the output signal.

7. The method for quantitative evaluation of mouse movement disorders based on motion reaction force testing technology according to claim 6, characterized in that, The parameter correction method for the sensors in the experimental setup in S2 is as follows: Through the calibration process, the static characteristic curves of multiple sensor bridges can be obtained. The static characteristic curves are fitted into a straight line by the least squares method, and the slope k of the straight line can be obtained, thereby obtaining the decoupling matrix [C]. By calibrating each sensor in the 3×8 force array, 24 decoupling matrices can be obtained. Inputting them into the backend of the LabVIEW acquisition program completes the parameter correction.

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