CN113317960A

CN113317960A - Analysis method for measuring and researching interaction force of wearing exoskeleton

Info

Publication number: CN113317960A
Application number: CN202110590219.1A
Authority: CN
Inventors: 朱云超; 朱钧; 周泽世; 张鑫彬; 陈立; 马昕
Original assignee: Fudan University; Zhuhai Fudan Innovation Research Institute
Current assignee: Fudan University; Zhuhai Fudan Innovation Research Institute
Priority date: 2021-05-28
Filing date: 2021-05-28
Publication date: 2021-08-31
Anticipated expiration: 2041-05-28
Also published as: CN113317960B

Abstract

The invention belongs to the technical field of measurement, and provides an analysis method for measuring and researching interaction force of a wearable exoskeleton. The interaction force of the exoskeleton and a human body in the normal direction is analyzed based on the kinematics data and the ground support reaction force data, and meanwhile, the numerical value and the trend of the interaction force are used as reference basis of biomechanics simulation software to adjust the strength and the position of virtual muscles to be close to actual values.

Description

Analysis method for measuring and researching interaction force of wearing exoskeleton

Technical Field

The invention belongs to the technical field of measurement, and particularly relates to an analysis method for measuring and researching interaction force of a wearable exoskeleton.

Background

In recent years, exoskeletons have gradually entered the field of vision of people as a means of enhancing or assisting athletic activities due to the increasing aging of the population and the improving quality of life of people. Regarding the structural design of the exoskeleton, the gait recognition of wearing the exoskeleton, the corresponding control algorithm and the auxiliary effect evaluation gradually become research hotspots of multiple subjects such as robotics, human factors engineering, military science and the like.

However, unreasonable mechanical structures of the exoskeleton, such as binding positions, motor mounting positions and transmission devices, can generate great unreasonable interaction force in a human-exoskeleton system, and greatly influence the comfort of the wearer wearing the exoskeleton and the subsequent treatment auxiliary effect. In addition, unreasonable control algorithms and incorrect gait recognition can also lead to severe walking instability, joint hyperextension or hyperextension, gait confusion and stumbling, and affect a normal walking of the wearer.

The existing exoskeleton is mainly used for analyzing electromyographic signals, metabolic rate and other modes, the preparation time is long, the equipment operation is complex, the physiological change of a human body before and after wearing the exoskeleton is mainly researched, but the physiological change of the human body is sensitive to the outside, and the method for analyzing the electromyographic signals and the metabolic rate is easily influenced by the state and mood of a testee and can generate interference on the evaluation of the performance of the exoskeleton, so that the accuracy degree of the interaction force analysis result is low.

Disclosure of Invention

The present invention is made to solve the above problems, and an object of the present invention is to provide an analysis method for measuring and studying interaction force between a wearing exoskeleton.

The invention provides an analysis method for measuring and researching interaction force of a wearable exoskeleton, which is used for analyzing interaction force generated between the exoskeleton and a user wearing the exoskeleton and is characterized by comprising the following steps: step S1, collecting the muscle and bone characteristics of the user, and establishing a muscle and bone model; step S2, establishing an exoskeleton model to be analyzed, and performing kinematic constraint and dynamic constraint on the musculoskeletal model and the exoskeleton model to be analyzed through biomechanical simulation software to obtain an exoskeleton coupling model to be analyzed; step S3, capturing the kinematic data and the ground support reaction force data of the user through the motion capture system, and establishing a contact element of the exoskeleton coupling model to be analyzed in biomechanics simulation software according to the kinematic data and the ground support reaction force data; step S4, setting analysis parameters of biomechanical simulation software, and performing inverse dynamics analysis on the exoskeleton coupling model to be analyzed and the contact element by using the biomechanical simulation software to obtain a human-computer interaction force prediction result; step S5, acquiring kinematic parameters and real-time current change data of the exoskeleton in the using process of a user; step S6, inputting the kinematic parameters and the real-time current data into biomechanical simulation software to obtain a human-computer interaction force detection result; and step S7, comparing and judging the muscle activation similarity of the human-computer interaction prediction obtained in the step S4 with the human-computer interaction detection result obtained in the step S6, if the muscle activation similarity is smaller than a preset threshold, judging to be negative, returning to the step S4, resetting parameters of the biomechanics simulation software, and if the muscle activation similarity is larger than or equal to the preset threshold, judging to be positive, outputting a human-computer interaction analysis result, and obtaining the optimal parameters of the biomechanics simulation software for analyzing the human-computer interaction.

In the analysis method for measuring and researching the interaction force of the wearing exoskeleton, the invention can also have the following characteristics: wherein, in step S5, kinematic parameters are acquired by hall current sensors provided on the exoskeleton.

In the analysis method for measuring and researching the interaction force of the wearing exoskeleton, the invention can also have the following characteristics: wherein the exoskeleton is driven by a driving motor, and in step S5, real-time current change data is obtained by collecting current changes of the driving motor.

In the analysis method for measuring and researching the interaction force of the wearing exoskeleton, the invention can also have the following characteristics: wherein, the biomechanical simulation software is Anybody software.

Action and Effect of the invention

The invention provides an analysis method for measuring and researching interaction force of a wearable exoskeleton, which is characterized in that a film pressure sensor arranged at the binding position of the exoskeleton and a human body is used for detecting the change of normal contact force of the exoskeleton and the human body in the whole gait process, and a current change data of a driving motor at a joint driving position is measured by a current sensor. Analyzing the interaction force of the exoskeleton and the human body in the normal direction based on the kinematic data and the ground support reaction force data, and simultaneously taking the numerical value and the trend as the reference basis of biomechanics simulation software to adjust the strength and the position of virtual muscles to be close to actual values; in a biomechanical simulation environment, firstly, a simulated exoskeleton and a human lower limb trunk are fixed through kinematic soft constraint, and the dynamic exoskeleton and a human musculoskeletal model are coupled through six-dimensional muscles. The motion of the lower limb is driven by using the lower limb kinematic data collected by the motion capture system. And (3) researching the interaction force generated by the man-machine in the cooperative motion through numerical simulation analysis. The muscle strength, the connection position and other parameters in the dynamic connection are adjusted to be consistent in the aspect of numerical value and trend. On the premise that the normal interaction force reaches the verification, the change conditions of the interaction force of the man-machine in each direction on the binding position can be obtained. Therefore, the analysis method for measuring and researching the interaction force of the worn exoskeleton, provided by the invention, takes the interaction force as an evaluation index of the reasonability of exoskeleton design, is convenient, fast and strong in operability, can simulate the situation of free activity under the laboratory condition of a motion capture system, reduces the wearing influence of the mechanical structure and the control algorithm of the exoskeleton on a wearer to the maximum extent, and improves the accuracy of an analysis result.

Drawings

FIG. 1 is a schematic diagram of a device for measuring a force of interaction of a wearable exoskeleton in an embodiment of the invention;

FIG. 2 is a flow chart of an analysis method for measuring interaction forces for studying a wearing exoskeleton in an embodiment of the present invention;

FIG. 3 is a comparison of a human-machine interaction prediction result and a human-machine interaction actual result obtained in an embodiment of the present invention;

fig. 4 is a diagram of the change of the interaction force and the moment in different directions obtained in the embodiment of the invention.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the efficacy of the measurement and research of the interaction force of the exoskeleton easy to understand, the following describes the analysis method for measuring and researching the exoskeleton wearing interaction force in detail with reference to the embodiment and the accompanying drawings.

< example >

This example specifically illustrates the analysis method for measuring and studying the interaction force of the wearing exoskeleton of the present invention.

The present embodiment takes the front, back, upper, lower, left, and right of the user as front, back, upper, lower, left, and right.

Fig. 1 is a schematic structural diagram of a device for measuring interaction force of a wearing exoskeleton in the embodiment.

As shown in fig. 1, the device 100 for measuring the force of interaction between a user wearing the exoskeleton 200 is mounted on the exoskeleton 200, and can detect the force of interaction between the user and the exoskeleton 200 during walking when the user wears the exoskeleton 200. Exoskeleton 200 includes a driver 210, a waist assembly 220, two thigh assemblies 230, two shank assemblies 240, and two foot assemblies 250.

The device 100 for measuring the interaction force of wearing the exoskeleton comprises a thigh detection module 10, a shank detection module 20, an instep detection module 30, an ankle detection module 40 and a main controller 50.

The number of the thigh detection modules 10 is two, and the two thigh detection modules 10 are both film pressure sensors, and the two thigh detection modules 10 are respectively fixed on the two thigh assemblies 230, face the front of the user, and are located at the middle position on the thigh assemblies 230. The thigh detection module 10 collects the acceleration, angular velocity and angle of the thigh of the user during walking, and also collects the real-time current change signal of the driver 210.

The number of the lower leg detection modules 20 is two, and the two lower leg detection modules 10 are both film pressure sensors, and are respectively fixed on the two lower leg assemblies 240, face the front of the user, and are located at the middle position on the lower leg assemblies 240. The shank detection module 20 collects the acceleration, angular velocity and angle of the shank of the user during walking, and also collects the real-time current change signal of the driver 210.

The number of the instep detection modules 30 is two, and the two instep detection modules 30 are both film pressure sensors, and the two instep detection modules 30 are respectively fixed on the two foot components 250 and are close to the instep of the user. The instep detection module 30 collects acceleration, angular velocity, and angle of the foot of the user during walking, and also collects a real-time current variation signal of the driver 210.

The number of ankle detection modules 40 is two, and the two ankle detection modules 40 are both film pressure sensors, and are respectively fixed on the two foot components 250 and close to the ankles of the user. The ankle detection module 40 collects acceleration, angular velocity, and angle generated by the ankle of the user during walking, and can also collect a real-time current change signal of the driver 210.

The main controller 50 is a single chip microcomputer, and is in communication connection with the thigh detecting module 10, the shank detecting module 20, the instep detecting module 30 and the ankle detecting module 40, and receives parameters and signals sent by the thigh detecting module 10, the shank detecting module 20, the instep detecting module 30 and the ankle detecting module 40 through a CAN bus.

In practical applications, the main controller 50 can collect data of one module or collect data of a plurality of modules simultaneously according to requirements. The main controller 50 receives the parameters and signals, stores the data in an onboard memory of the single chip microcomputer through analog-to-digital conversion, and can also upload the data to a computer for display and processing in real time through the WIFI module.

Fig. 2 is a flowchart of an analysis method for measuring and studying interaction force of wearing an exoskeleton in the embodiment.

As shown in fig. 2, the analysis method for measuring and studying interaction force of wearing exoskeleton provided by the embodiment includes the following steps:

and step S1, collecting the muscle and bone characteristics of the user and establishing a muscle and bone model.

And step S2, establishing an exoskeleton model to be analyzed, and performing kinematic constraint and dynamic constraint on the musculoskeletal model and the exoskeleton model to be analyzed through biomechanical simulation software to obtain an exoskeleton coupling model to be analyzed.

The biomechanical simulation software in this embodiment is Anybody software. Kinematic constraints are to make the human and the exoskeleton move relatively in line, to simulate flexible compression between the lower limb muscles and the exoskeleton, and to allow relatively small errors to be generated during kinematic solution. The kinetic constraint is used to predict the interaction force generated during the contact process by the six-dimensional muscular constraint.

In biomechanics simulation software, 12 virtual muscles are established at the binding positions of an external skeleton and a human body for kinematic connection, and the 12 virtual muscles are respectively responsible for forward and reverse motions with 6 degrees of freedom under a space coordinate system.

In this embodiment, the six dimensions respectively refer to the X, Y, Z axis and the moment of stress, the normal direction of the exoskeleton contacting with the human is X, the direction pointing to the inner side of the human body is Z, and the Y direction is determined according to the right-hand screw rule.

Step S3, capturing the kinematic data and the ground reaction force data of the user by the motion capture system, and establishing the contact elements of the exoskeleton coupling model to be analyzed in the biomechanical simulation software according to the kinematic data and the ground reaction force data.

Under the experimental condition of the motion capture system, the trajectory data of each marker point attached to a human body in the space is captured and matched with cursor points in software, so that the motion of a model in biomechanics simulation software is driven, the kinematic data of the trunk of the lower limbs of the human body and the ground support reaction force data are collected and are led into biomechanics analysis software in a C3D data format to serve as a kinematic and inverse kinematic analysis basis, and the angle, the angular velocity and the acceleration of each part can be obtained through kinematic analysis. After the soft synchronization with the hardware equipment is realized, the current data measured by the hardware equipment is converted into the moment of opposite stress, and the moment of opposite stress acts on the joint driving position in the biomechanics simulation software in an interpolation function mode.

In the embodiment, the motion of the lower limbs of the human body and the relative motion between the lower limb exoskeleton and the human body are captured in a gait analysis laboratory as input environment variables, the change conditions of the moment of each joint and the muscle activation degree of the human body after the exoskeleton is worn are obtained through kinematics and inverse dynamics analysis simulation, and the six-dimensional interaction force generated by the exoskeleton at the binding position on the human body can be analyzed through biomechanics simulation software under the condition that the normal stress of the exoskeleton and the human body is measured, so that the six-dimensional interaction force generated by the exoskeleton and the human body at the interaction position can be analyzed through biomechanics simulation software.

And step S4, setting analysis parameters of the biomechanics simulation software, and performing inverse dynamics analysis on the exoskeleton coupling model to be analyzed and the contact element by using the biomechanics simulation software to obtain a human-computer interaction force prediction result.

The contact elements in this embodiment are the aforementioned six-dimensional muscles, and the computational interaction forces, kinematic data and ground reaction forces, affect the results of the calculations by muscle recruitment.

The method for obtaining the parameters of the biomechanical simulation software comprises the following steps:

wherein G is the predetermined muscle energy consumption, f_iFor the parameter to be solved, N is the maximum contractile capacity of the muscle and p is an index.

Gradually reducing the G value in the iterative calculation process of inverse dynamics to minimize the finally calculated value, and finally calculating the muscle force f_iIs considered to correspond to the force generated by the relevant muscles of the human body during actual movement. The P-value is an index whose value may take the order of 1, 2, 3 or even higher, whose value mainly affects the distribution of the load between the various muscles. In this example, a p value of 3 was selected.

Different parameter settings can affect the analysis result of the final interaction force, so that the normal interaction force measured by hardware equipment is required to be used as a reference, and the parameter settings of the virtual muscles are modified, so that similar numerical values and variation trends are expected to be realized, and an optimal parameter setting scheme is obtained.

Step S5, collecting kinematic parameters and real-time current change data of the exoskeleton during use by the user.

In this embodiment, kinematic parameters and real-time current change data are collected through a film pressure sensor and a hall sensor in a device for measuring the interaction force of the wearable exoskeleton, and the real-time current change data and the double-sole FSR data are uploaded to a PC terminal through a WIFI module while the parameters and the data are stored in an onboard memory. The real-time current data is used for analyzing the output torque in the motion process and the kinematic data measured by the motion capture system according to the relation between the motor current and the output torque.

And step S6, inputting the kinematic parameters and the real-time current data into biomechanical simulation software to obtain a human-computer interaction force detection result.

And step S7, comparing and judging the muscle activation similarity of the human-computer interaction force prediction result obtained in the step S4 with the human-computer interaction force detection result obtained in the step S6, if the muscle activation similarity is smaller than a preset threshold, judging to be negative, returning to the step S4, resetting parameters of the biomechanics simulation software, and if the muscle activation similarity is larger than or equal to the preset threshold, judging to be positive, outputting a human-computer interaction force analysis result, and obtaining the optimal parameters of the biomechanics simulation software for analyzing the human-computer interaction force.

Fig. 3 is a comparison diagram of the human-computer interaction prediction result and the human-computer interaction actual result obtained in the present embodiment.

As shown in fig. 3, in the normalization comparison between the human-computer interaction prediction result and the human-computer interaction detection result, the two curves have good consistency, and three peaks appear in the whole gait cycle, which are respectively located at the middle stage, the end stage and the end stage of the support phase in the gait cycle, and it is proved that the interaction force obtained through Anybody simulation calculation meets the actual result.

Fig. 4 is a diagram of the variation of the interaction force and the moment in different directions obtained in the present embodiment.

As shown in fig. 4, the interaction forces between the exoskeleton and the person are not only normal, but it should be that six-dimensional interaction forces include interaction forces in the direction of three human bodies X, Y, Z and corresponding torques.

Effects and effects of the embodiments

According to the analysis method for measuring and researching the interaction force of the wearable exoskeleton, the change of the normal contact force of the exoskeleton and a human body in the whole gait process is detected through the film pressure sensor arranged at the binding position of the exoskeleton and the human body, and the current change data of the driving motor at the joint driving position is detected through the current sensor. Analyzing the interaction force of the exoskeleton and the human body in the normal direction based on the kinematic data and the ground support reaction force data, and simultaneously taking the numerical value and the trend as the reference basis of biomechanics simulation software to adjust the strength and the position of virtual muscles to be close to actual values; in a biomechanical simulation environment, firstly, a simulated exoskeleton and a human lower limb trunk are fixed through kinematic soft constraint, and the dynamic exoskeleton and a human musculoskeletal model are coupled through six-dimensional muscles. The motion of the lower limb is driven by using the lower limb kinematic data collected by the motion capture system. And (3) researching the interaction force generated by the man-machine in the cooperative motion through numerical simulation analysis. The muscle strength, the connection position and other parameters in the dynamic connection are adjusted to be consistent in the aspect of numerical value and trend. On the premise that the normal interaction force reaches the verification, the change conditions of the interaction force of the man-machine in each direction on the binding position can be obtained. Therefore, the analysis method for measuring and researching the interaction force of the wearable exoskeleton provided by the embodiment takes the interaction force as an evaluation index of the reasonability of exoskeleton design, is convenient, fast and strong in operability, can simulate the situation of free activity under the laboratory condition of a motion capture system, reduces the wearing influence of the mechanical structure and the control algorithm of the exoskeleton on a wearer to the maximum extent, and improves the accuracy of an analysis result.

The above embodiments are preferred examples of the present invention, and are not intended to limit the scope of the present invention.

Claims

1. An analysis method for measuring and researching interaction force generated between an exoskeleton and a user wearing the exoskeleton, comprising the following steps:

step S1, collecting the muscle and bone characteristics of the user and establishing a muscle and bone model;

step S2, establishing an exoskeleton model to be analyzed, and performing kinematic constraint and dynamic constraint on the musculoskeletal model and the exoskeleton model to be analyzed through biomechanical simulation software to obtain an exoskeleton coupling model to be analyzed;

step S3, capturing kinematic data and ground support reaction force data of the user through a motion capture system, and establishing a contact element of the exoskeleton coupling model to be analyzed in the biomechanics simulation software according to the kinematic data and the ground support reaction force data;

step S4, setting analysis parameters of the biomechanical simulation software, and carrying out inverse dynamics analysis on the exoskeleton coupling model to be analyzed and the contact element by using the biomechanical simulation software to obtain a human-computer interaction force prediction result;

step S5, acquiring kinematic parameters and real-time current change data of the exoskeleton in the using process of the user;

step S6, inputting the kinematic parameters and the real-time current data into the biomechanical simulation software to obtain a human-computer interaction force detection result;

and step S7, comparing and judging the muscle activation similarity of the human-computer interaction prediction obtained in the step S4 with the human-computer interaction detection result obtained in the step S6, if the muscle activation similarity is smaller than a preset threshold, judging to be negative, returning to the step S4, resetting the parameters of the biomechanical simulation software, and if the muscle activation similarity is larger than or equal to the preset threshold, judging to be positive, outputting a human-computer interaction analysis result, and obtaining the optimal parameters of the biomechanical simulation software for analyzing the human-computer interaction.

2. The analytical method for measuring interaction forces between a research wearable exoskeleton of claim 1, wherein the analytical method comprises the steps of:

wherein, in step S5, the kinematic parameters are collected by hall current sensors disposed on the exoskeleton.

3. The analytical method for measuring interaction forces between a research wearable exoskeleton of claim 1, wherein the analytical method comprises the steps of:

wherein the exoskeleton is driven by a drive motor,

in step S5, the real-time current change data is obtained by collecting the current change of the driving motor.

4. The analytical method for measuring interaction forces between a research wearable exoskeleton of claim 1, wherein the analytical method comprises the steps of:

wherein, the biomechanical simulation software is Anybody software.