CN113478462A - Method and system for controlling intention assimilation of upper limb exoskeleton robot based on surface electromyogram signal - Google Patents
Method and system for controlling intention assimilation of upper limb exoskeleton robot based on surface electromyogram signal Download PDFInfo
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Abstract
The invention provides an intention assimilation control method and system for an upper limb exoskeleton robot based on a surface electromyogram signal, which comprises the following steps: step 1: establishing an upper limb exoskeleton robot dynamic model by using a Kenn method; step 2: performing intention recognition through a surface electromyogram signal based on a dynamic model; and step 3: the intention assimilation control is performed by the virtual object. The intention assimilation control method provided by the invention covers continuous interactive behaviors from cooperation to competition, has less strength guidance, and is safer obstacle avoidance and wider interactive behaviors.
Description
Technical Field
The invention relates to the technical field of man-machine interaction, artificial intelligence and interaction control, in particular to an intention assimilation control method and system for an upper limb exoskeleton robot based on surface electromyogram signals.
Background
In recent years, the robot technology is developed rapidly, particularly, a man-machine interface is the most important link in the man-machine interaction research, the quality of signals of the man-machine interface directly influences the control effect and the experimental result, the man-machine interface can measure the human body force and the movement intention signals, the surface electromyogram signals have great advantages in the aspects of accuracy and time delay, and the estimation on the human body movement and force is accurate.
In the aspect of control strategies, the diversification of the control strategies of the interactive robot is an important factor for popularization and application, the basic control strategy is PID control, the application is simple and convenient, but the control can be only carried out according to a fixed track, and the human intention cannot be introduced; in order to reflect human intention, surface electromyographic signals are also introduced into a robot control strategy, meanwhile, the electromyographic signals are connected with human joints by means of an artificial intelligence algorithm, a certain control effect is achieved, and from the concept of homotopic switching of master and slave roles, human-computer interaction behaviors can be divided into: assistance, cooperation, collaboration, opposition, and the like, the intended assimilation control covers continuous interactive behaviors from cooperation to competition, and less strength guidance, safer obstacle avoidance, and wider interactive behaviors.
Patent document CN108283569A (application number: CN201711449077.7) discloses a control system and a control method for an exoskeleton robot, which are used for solving the problems that the existing rehabilitation exoskeleton robot has poor universality, cannot correctly judge the requirement of human body movement intention, and cannot realize the function and effect of man-machine cooperation. The exoskeleton robot control system comprises an attitude sensor, an angle sensor, a pressure sensor, a surface electromyogram signal sensor, a processor, an exoskeleton robot wearing part and a human-computer interaction module.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide an intention assimilation control method and system for an upper limb exoskeleton robot based on surface electromyogram signals.
The invention provides an intention assimilation control method of an upper limb exoskeleton robot based on a surface electromyogram signal, which comprises the following steps:
step 1: establishing an upper limb exoskeleton robot dynamic model by using a Kenn method;
step 2: performing intention recognition through a surface electromyogram signal based on a dynamic model;
and step 3: the intention assimilation control is performed by the virtual object.
Preferably, the step 1 comprises:
step 1.1: there is no relative motion between the robot, the person and the object, and the robot and the person together manipulate the object, the object satisfying the dynamic equation:
wherein,as the second derivative of the position coordinates of the object with respect to time, f and uhIs the force of the robot and person on the object, MoIs a mass matrix of the object, GoIs the weight of the object;
step 1.2: establishing an upper limb exoskeleton robot dynamics model by using a Kenn method to obtain a joint space dynamics equation when the upper limb exoskeleton robot with n degrees of freedom is in contact with the environment:
wherein q is the joint coordinate of the robot, tauqFor control input, JT(q) is the Jacobian matrix, Mq(q) is the robot inertia matrix,is the Coriolis and centrifugal torque, Gq(q) is the moment of gravity;
and converting into a robot operating space to obtain a kinetic equation:
Mr、Cr、Grrespectively representing an inertia matrix, a Coriolis force and centrifugal force matrix and a gravity matrix of the upper limb exoskeleton robot under a Cartesian space coordinate system, and symbolsRepresenting a pseudo-inverse of the matrix;
step 1.3: simultaneous equations (1) and (3) are obtained to obtain the combined kinetic equation of the object and the robot:
M≡Mo+Mr,G≡Go+Gr,C≡Cr…………(5)
m, C, G respectively representing inertia matrix, Coriolis force and centrifugal force matrix and gravity matrix of the upper limb exoskeleton robot and human interaction system in a Cartesian space coordinate system;
step 1.4: the position, the speed and the human force of the tail end of the upper limb exoskeleton robot are measured, a robot controller with gravity compensation and linear feedback is adopted, and the expression is as follows:
where τ is the target position of the robot, L1And L2Is a gain corresponding to position error and velocity;
the force of a person acting on an object is modeled as:
wherein L ish,1And Lh,2Control gain, τ, for humanshAnd (5) bringing the formulas (6) and (7) into the formula (5) to obtain the dynamic equation of the upper limb exoskeleton robot and human interactive closed-loop system for the target position of the human:
preferably, the step 2 comprises:
step 2.1: collecting electromyographic signals of wrists, forearms and elbows of a person through an electromyograph;
step 2.2: filtering, data segmentation and feature extraction are carried out on the collected electromyographic signals, and feature extraction is carried out according to waveform types, so that the extracted features correspond to different intention categories;
step 2.3: training and predicting by using a multi-criterion linear programming in a database and combining a classification method of an online random forest;
step 2.4: during model prediction, the prediction category of each base classifier is compared with the corresponding confidence coefficient and a preset threshold value to determine whether the base classifier votes, finally, a Boost algorithm is used for collecting voting results of all the base classifiers and carrying out weighted summation to find the prediction category with the largest votes, and when the votes are larger than the mean value, the activity intention is output.
Preferably, the step 3 comprises:
step 3.1: by a virtual target of a personEvaluating the influence of human on the dynamics of the upper limb exoskeleton robot and the human interaction system, wherein the formula is as follows:
wherein the human controls the gainAndusing measured average values, or the same values as the robot controller gains, i.e.The superscript symbol v represents the estimated value;
step 3.2: using an intention recognition method based on surface electromyography signals, or by internal model parameterizationAnd estimating, wherein the expression is as follows:
wherein the superscript symbol T represents transposition, and θ is the virtual target position of the person being calculatedThe vector of parameters of (a) is, t represents time, m is a predetermined parameter, and thereforeIs a quantity that is determined by the internal model parameters and varies with time;
state vector using upper limb exoskeleton robot and human interaction systemThe extended model is obtained after substituting the formula (5):
where φ represents: state vector of upper limb exoskeleton robot and human interaction system, v ∈ N (0, E [ v, v ]T]) Is the system noise, i.e., mean 0, variance E [ v, vT]Gaussian noise of (2);
step 3.3: measuring the position and the speed of the end point of the robot and the interaction force with a human through a sensor to obtain a measurement vector of the upper limb exoskeleton robot and the human interaction system:
wherein, mu is N (0, E [ mu, mu ]T]) Is the environmental measurement noise, i.e., the mean is 0 and the variance is E [ mu, mu ]T]Gaussian noise of (2);
step 3.4: calculating an extended state estimate of the robot using the system observer:
wherein Λ represents an estimated value; z represents a measurement vector of the upper limb exoskeleton robot and the human interaction system;
linear quadratic estimation gain K-PHTR-1P is a positive definite matrix obtained by solving the ricatt differential equation:
wherein the noise covariance matrix Q ≡ E [ v, v ≡ E ≡ VT],R≡E[μ,μT]And a denotes a system matrix, and is substituted into equation (11) and expressed as follows:
preferably, the interaction between the person and the robot is determined by the relationship τ and τ between the person and the robothTo determine:
when τ is τhRepresenting assistance of a robot using a human virtual target, the robot follows its original target τr;
When τ is 2 τr-τhWhile, the robot imposes its own target by eliminating the human target from the upper extremity exoskeleton robot and human interaction system;
interactive behavior assimilation from the estimated target position of the human target design robot using the following formula:
τrrepresenting an original target position of the upper limb exoskeleton robot; lambda represents the super-position for adjusting the original target position and the human target position of the upper limb exoskeleton robotAnd the parameters are dynamically adjusted according to the terminal position x.
The invention provides an upper limb exoskeleton robot intention assimilation control system based on a surface electromyogram signal, which comprises:
module M1: establishing an upper limb exoskeleton robot dynamic model by using a Kenn method;
module M2: performing intention recognition through a surface electromyogram signal based on a dynamic model;
module M3: the intention assimilation control is performed by the virtual object.
Preferably, the module M1 includes:
module M1.1: there is no relative motion between the robot, the person and the object, and the robot and the person together manipulate the object, the object satisfying the dynamic equation:
wherein,as the second derivative of the position coordinates of the object with respect to time, f and uhIs the force of the robot and person on the object, MoIs a mass matrix of the object, GoIs the weight of the object;
module M1.2: establishing an upper limb exoskeleton robot dynamics model by using a Kenn method to obtain a joint space dynamics equation when the upper limb exoskeleton robot with n degrees of freedom is in contact with the environment:
wherein q is the joint coordinate of the robot, tauqFor control input, JT(q) is the Jacobian matrix, Mq(q) is the robot inertia matrix,is Coriolis and centrifugal torqueMoment, Gq(q) is the moment of gravity;
and converting into a robot operating space to obtain a kinetic equation:
Mr、Cr、Grrespectively representing an inertia matrix, a Coriolis force and centrifugal force matrix and a gravity matrix of the upper limb exoskeleton robot under a Cartesian space coordinate system, and symbolsRepresenting a pseudo-inverse of the matrix;
module M1.3: simultaneous equations (1) and (3) are obtained to obtain the combined kinetic equation of the object and the robot:
M≡Mo+Mr,G≡Go+Gr,C≡Cr…………(5)
m, C, G respectively representing inertia matrix, Coriolis force and centrifugal force matrix and gravity matrix of the upper limb exoskeleton robot and human interaction system in a Cartesian space coordinate system;
module M1.4: the position, the speed and the human force of the tail end of the upper limb exoskeleton robot are measured, a robot controller with gravity compensation and linear feedback is adopted, and the expression is as follows:
where τ is the target position of the robot, L1And L2Is a gain corresponding to position error and velocity;
the force of a person acting on an object is modeled as:
wherein L ish,1And Lh,2Control gain, τ, for humanshAnd (5) bringing the formulas (6) and (7) into the formula (5) to obtain the dynamic equation of the upper limb exoskeleton robot and human interactive closed-loop system for the target position of the human:
preferably, the module M2 includes:
module M2.1: collecting electromyographic signals of wrists, forearms and elbows of a person through an electromyograph;
module M2.2: filtering, data segmentation and feature extraction are carried out on the collected electromyographic signals, and feature extraction is carried out according to waveform types, so that the extracted features correspond to different intention categories;
module M2.3: training and predicting by using a multi-criterion linear programming in a database and combining a classification method of an online random forest;
module M2.4: during model prediction, the prediction category of each base classifier is compared with the corresponding confidence coefficient and a preset threshold value to determine whether the base classifier votes, finally, a Boost algorithm is used for collecting voting results of all the base classifiers and carrying out weighted summation to find the prediction category with the largest votes, and when the votes are larger than the mean value, the activity intention is output.
Preferably, the module M3 includes:
module M3.1: by a virtual target of a personEvaluating the influence of human on the dynamics of the upper limb exoskeleton robot and the human interaction system, wherein the formula is as follows:
wherein the human controls the gainAndusing measured average values, or the same values as the robot controller gains, i.e.The superscript symbol v represents the estimated value;
module M3.2: using an intention recognition method based on surface electromyography signals, or by internal model parameterizationAnd estimating, wherein the expression is as follows:
wherein the superscript symbol T represents transposition, and θ is the virtual target position of the person being calculatedThe vector of parameters of (a) is, t represents time, m is a predetermined parameter, and thereforeIs a quantity that is determined by the internal model parameters and varies with time;
state vector using upper limb exoskeleton robot and human interaction systemThe extended model is obtained after substituting the formula (5):
where φ represents: state vector of upper limb exoskeleton robot and human interaction system, v ∈ N (0, E [ v, v ]T]) Is the system noise, i.e., mean 0, variance E [ v, vT]Gaussian noise of (2);
module M3.3: measuring the position and the speed of the end point of the robot and the interaction force with a human through a sensor to obtain a measurement vector of the upper limb exoskeleton robot and the human interaction system:
wherein, mu is N (0, E [ mu, mu ]T]) Is the environmental measurement noise, i.e., the mean is 0 and the variance is E [ mu, mu ]T]Gaussian noise of (2);
module M3.4: calculating an extended state estimate of the robot using the system observer:
wherein Λ represents an estimated value; z represents a measurement vector of the upper limb exoskeleton robot and the human interaction system;
linear quadratic estimation gain K-PHTR-1P is a positive definite matrix obtained by solving the ricatt differential equation:
wherein the noise covariance matrix Q ≡ E [ v, v ≡ E ≡ VT],R≡E[μ,μT]And a denotes a system matrix, and is substituted into equation (11) and expressed as follows:
preferably, the interaction between the person and the robot is determined by the relationship τ and τ between the person and the robothTo determine:
when τ is τhRepresenting assistance of a robot using a human virtual target, the robot follows its original target τr;
When τ is 2 τr-τhWhile, the robot imposes its own target by eliminating the human target from the upper extremity exoskeleton robot and human interaction system;
interactive behavior assimilation from the estimated target position of the human target design robot using the following formula:
τrrepresenting an original target position of the upper limb exoskeleton robot; and lambda represents a hyper-parameter for adjusting the original target position and the human target position of the upper limb exoskeleton robot, and is dynamically adjusted according to the tail end position x.
Compared with the prior art, the invention has the following beneficial effects:
(1) the invention introduces the surface electromyogram signal into the robot control strategy, and has advantages in the aspects of accuracy and time delay;
(2) the intention assimilation control method provided by the invention covers continuous interaction behaviors from cooperation to competition, has less strength guidance, and is safer obstacle avoidance and wider interaction behaviors;
(3) the method is simple and easy to implement, and is a compliance control method with high robustness.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1 is a schematic diagram of an intention assimilation control method of an upper limb exoskeleton robot based on surface electromyogram signals;
FIG. 2 is a schematic view of an obstacle avoidance and auxiliary task scenario of the present invention;
FIG. 3 is a schematic flow chart of an intention identification method based on surface electromyography signals according to the present invention;
FIG. 4 is a schematic diagram of the MCLP Boost algorithm of the present invention;
fig. 5 is a schematic diagram of the variation of the human-computer interaction strategy corresponding to the parameter λ adjustment of the present invention.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.
Example (b):
as shown in fig. 1, a schematic diagram of an intention assimilation control method for an upper limb exoskeleton robot based on a surface electromyogram signal according to the present invention includes an upper limb exoskeleton robot dynamics model established by a Kane method, an intention identification method based on a surface electromyogram signal, and an intention assimilation control method, and different task scenarios are shown in fig. 2, and the intention assimilation control method according to the present invention can unify different human-computer interaction strategies and perform continuous control;
further, the specific process of establishing the upper limb exoskeleton robot dynamics model by using the Kane method comprises the following steps:
1) assuming that there is no relative motion between the robot gripper, the hand, and the object, and that the robot gripper and the hand are manipulating a rigid object together, the object is a mass point. General object manipulation considers only linear motion, and the object satisfies the dynamic equation:
where x (t) is the position coordinate of the object, f and uhIs the force of the robot and person on the object, MoIs a mass matrix of the object, GoIs the weight of the object.
2) The method comprises the following steps of utilizing an upper limb exoskeleton robot dynamics model established by a Kane method to obtain a joint space dynamics equation when the upper limb exoskeleton robot with n degrees of freedom is in contact with the environment:
wherein q is the joint coordinate of the robot, tauqFor control input, JT(q) is the Jacobian matrix, Mq(q) is the robot inertia matrix,is the Coriolis and centrifugal torque, Gq(q) is the moment of gravity;
and converting into a robot operating space to obtain a kinetic equation:
Mr、Cr、Grthe meaning of (1) is respectively an inertia matrix, a Coriolis force and centrifugal force matrix and a gravity matrix of the upper limb exoskeleton robot under a Cartesian space coordinate system; symbolRepresenting a pseudo-inverse of the matrix;
3) the simultaneous equations (1) and (3) can obtain the combined kinetic equation of the object and the robot:
M≡Mo+Mr,G≡Go+Gr,C≡Cr…………(5)
m, C, G, respectively representing an inertia matrix, a Coriolis force and centrifugal force matrix and a gravity matrix of the upper limb exoskeleton robot and human interaction system in a Cartesian space coordinate system;
4) consider the robot information about its local environment and make measurements of the position, velocity and human force at the end of the upper extremity exoskeleton robot interaction system, all affected by measurement noise. With a robot controller with gravity compensation and linear feedback:
where τ is the target position of the robot, L1And L2Is a gain corresponding to the position error and the velocity.
The force of a human hand on an object is modeled as:
wherein L ish,1And Lh,2Control gain, τ, for humanshSubstituting equations (6) and (7) into equation (5) for the target position of the human can obtain the dynamic equation of the upper limb exoskeleton robot and human interactive closed-loop system:
further, as shown in fig. 3, the intention identification method based on the surface electromyogram signal specifically includes the following steps:
1) collecting electromyographic signals of wrists, forearms and elbows of a person through an electromyograph;
2) filtering the collected electromyographic signals, then carrying out data segmentation and feature extraction, wherein the overlap is not applicable when long-sequence waveforms are used for feature extraction, and the overlap operation can be considered when the waveforms are short, so that the extracted features can correspond to different intention categories;
3) the MCLPBoost algorithm is shown in FIG. 4, and has good generalization performance, so that the method is based on comparison, and has the characteristic and advantage of small time overhead compared with a calculation model when prediction is carried out;
4) during model prediction, comparing the prediction category of each base classifier with the corresponding confidence coefficient (probability) with a preset threshold value, determining whether the base classifier votes, finally collecting the voting results of all the base classifiers by using a Boost algorithm, weighting and summing the voting results, finding the prediction category with the largest number of votes, and outputting the activity intention when the number of votes is greater than the mean value;
5) the result of the intention recognition based on the surface electromyographic signal can be used to generate a "virtual" object.
Further, the influence of human on the dynamics of the upper limb exoskeleton robot and human interaction system is completely dependent on uhNo matter what internal model it is based on, an alternative method is developed that does not require the estimation of human control gains, a "virtual" target being generated by using arbitrary values of these assumed gainsThe intention assimilation control method comprises the following specific processes:
1) "virtual" targetThe influence of human on the dynamics of the upper limb exoskeleton robot and human interaction system can be effectively evaluated if the following conditions are met:
wherein the virtual human controls the gainAndsome average value measured from many people, or the same value as the robot controller gain, may be used, i.e.
2) To estimateThe surface electromyogram signal-based intention recognition method of claim 3 may be used, or it may be parameterized using an internal model:
wherein theta means calculating a virtual target position of a personThe vector of parameters of (a) is,t represents time, m is a predetermined parameter, and thereforeFor the time-varying quantities determined by the internal model parameters, state vectors are usedSubstituting this into equation (5) yields an extended model:
where φ represents: state vectors of the upper limb exoskeleton robot and the human interaction system; v is an element of N (0, E [ v, v ]T]) Is the system noise, i.e., mean 0, variance E [ v, vT]Gaussian noise.
3) Considering that the robot can measure its end position and velocity and the interaction force with the person with suitable sensors, the measurement vector of the robot is obtained:
wherein, mu is N (0, E [ mu, mu ]T]) Is the environmental measurement noise, i.e., the mean is 0 and the variance is E [ mu, mu ]T]Gaussian noise.
4) However, in equation (10)And θ are unknown, so the following system observer is used to calculate the extended state estimate of the robot:
where Λ represents the estimated value, z represents: measuring vectors of the upper limb exoskeleton robot and the human interaction system; linear quadratic estimation gain K-PHTR-1P is a positive definite matrix obtained by solving the ricatt differential equation:
wherein the noise covariance matrix Q ≡ E [ v, v ≡ E ≡ VT],R≡E[μ,μT]Using a to denote the system matrix, equation (11) can be expressed as follows:
5) The interaction between a person and a robot can be determined by the relationships τ and τ between the person and the robothTo determine, e.g. when τ ═ τhCorresponding to the assistance of the robot using the human virtual target, when tau is taurThe robot follows its original target taurWhen τ is 2 τr-τhCorresponding to "confrontation", i.e. the robot imposes its own target by eliminating the target of the human from the upper extremity exoskeleton robot and human interaction system.
To assimilate the interactive behavior, the target position of the robot is designed from the estimated human target using the following equation:
τrrepresents: an original target position of the upper limb exoskeleton robot; λ represents: adjusting hyper-parameters of an original target position and a human target position of the upper limb exoskeleton robot, and dynamically adjusting according to a terminal position x;
the variation of the human-computer interaction strategy corresponding to the adjustment of the parameter lambda is shown in FIG. 5 when lambda is measured<1, the intention assimilation controller will coordinate human-machine goals; when λ is 1, the intended assimilation controller will ignoreThereby completing man-machine cooperation; when lambda is 2, the intention assimilation controller eliminates the influence of the simulated human on the dynamic state of the upper limb exoskeleton robot and the human interaction systemAnd the positions of the upper limb exoskeleton robot and the human interaction system finally converge to the target tau of the intention assimilation controllerr。
Further, verifyThe stability of the human-computer interaction system after introduction, the human target can be estimated by the second equation of equation (13)
Substituting the corrected equation (6) into the combined kinetics equation (5) yields:
wherein,representing the error between the estimated value and the actual value, if definedAnd the force (7) of the human hand on the object is substituted into the above equation to obtain:
thus, τ can be analyzedrAnd τhInfluence on the dynamic system, taking into account the steady-state position:
equation (19) is simplified to analyze stability by defining the following equation:
deducing:
this accounts for the position error x-xssWill disappear if the error of the estimation of the manpower is
The formal formula (15) and the system observer (13) in the state space according to the dynamics of the upper limb exoskeleton robot and the human interaction system are as follows:
by defining ξ ≡ [ x-x ]ss,x,φT]TCombining equation (22) and equation (23) yields:
where ξ is the system state vector defined in the system transient performance analysis, this equation is a combined system that includes the system dynamics and the observer.
Can be calculated by solving the following characteristic equationFurther study of the stability of equation (24):
[yI-(A-KH)][My2+(C+L2)y+L1]=0…………(25)
the stability of the two systems is respectively checked by utilizing the Lyapunov theory, and the stability of the first system is firstly proved by considering a Lyapunov candidate function:
the time derivative can be:
the stability of the second system is then demonstrated by considering the lyapunov candidate function:
Pvby, etcThe Riccati equation in equation (14) can be found:
the time derivative can be:
combining equation (13) can result in:
substituting equation (31) can obtain:
it is thus demonstrated that both systems in equation (26) are stable and therefore the upper extremity exoskeleton robot and human interaction system is stable.
Those skilled in the art will appreciate that, in addition to implementing the systems, apparatus, and various modules thereof provided by the present invention in purely computer readable program code, the same procedures can be implemented entirely by logically programming method steps such that the systems, apparatus, and various modules thereof are provided in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers and the like. Therefore, the system, the device and the modules thereof provided by the present invention can be considered as a hardware component, and the modules included in the system, the device and the modules thereof for implementing various programs can also be considered as structures in the hardware component; modules for performing various functions may also be considered to be both software programs for performing the methods and structures within hardware components.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.
Claims (10)
1. An intention assimilation control method of an upper limb exoskeleton robot based on a surface electromyogram signal is characterized by comprising the following steps:
step 1: establishing an upper limb exoskeleton robot dynamic model by using a Kenn method;
step 2: performing intention recognition through a surface electromyogram signal based on a dynamic model;
and step 3: the intention assimilation control is performed by the virtual object.
2. The method for controlling the intention assimilation of an upper limb exoskeleton robot based on surface electromyography according to claim 1, wherein the step 1 comprises:
step 1.1: there is no relative motion between the robot, the person and the object, and the robot and the person together manipulate the object, the object satisfying the dynamic equation:
wherein,as the second derivative of the position coordinates of the object with respect to time, f and uhIs the force of the robot and person on the object, MoIs a mass matrix of the object, GoIs the weight of the object;
step 1.2: establishing an upper limb exoskeleton robot dynamics model by using a Kenn method to obtain a joint space dynamics equation when the upper limb exoskeleton robot with n degrees of freedom is in contact with the environment:
wherein q is the joint coordinate of the robot, tauqFor control input, JT(q) is the Jacobian matrix, Mq(q) is the robot inertia matrix,is the Coriolis and centrifugal torque, Gq(q) is the moment of gravity;
and converting into a robot operating space to obtain a kinetic equation:
Mr、Cr、Grrespectively representing an inertia matrix, a Coriolis force and centrifugal force matrix and a gravity matrix of the upper limb exoskeleton robot under a Cartesian space coordinate system, and symbolsRepresenting a pseudo-inverse of the matrix;
step 1.3: simultaneous equations (1) and (3) are obtained to obtain the combined kinetic equation of the object and the robot:
M≡Mo+Mr,G≡Go+Gr,C≡Cr…………(5)
m, C, G respectively representing inertia matrix, Coriolis force and centrifugal force matrix and gravity matrix of the upper limb exoskeleton robot and human interaction system in a Cartesian space coordinate system;
step 1.4: the position, the speed and the human force of the tail end of the upper limb exoskeleton robot are measured, a robot controller with gravity compensation and linear feedback is adopted, and the expression is as follows:
where τ is the target position of the robot, L1And L2Is a gain corresponding to position error and velocity;
the force of a person acting on an object is modeled as:
wherein L ish,1And Lh,2Control gain, τ, for humanshAnd (5) bringing the formulas (6) and (7) into the formula (5) to obtain the dynamic equation of the upper limb exoskeleton robot and human interactive closed-loop system for the target position of the human:
3. the method for controlling the intention assimilation of an upper limb exoskeleton robot based on surface electromyography according to claim 1, wherein the step 2 comprises:
step 2.1: collecting electromyographic signals of wrists, forearms and elbows of a person through an electromyograph;
step 2.2: filtering, data segmentation and feature extraction are carried out on the collected electromyographic signals, and feature extraction is carried out according to waveform types, so that the extracted features correspond to different intention categories;
step 2.3: training and predicting by using a multi-criterion linear programming in a database and combining a classification method of an online random forest;
step 2.4: during model prediction, the prediction category of each base classifier is compared with the corresponding confidence coefficient and a preset threshold value to determine whether the base classifier votes, finally, a Boost algorithm is used for collecting voting results of all the base classifiers and carrying out weighted summation to find the prediction category with the largest votes, and when the votes are larger than the mean value, the activity intention is output.
4. The method for controlling the intention assimilation of an upper limb exoskeleton robot based on surface electromyography according to claim 2, wherein the step 3 comprises:
step 3.1: by a virtual target of a personEvaluating the influence of human on the dynamics of the upper limb exoskeleton robot and the human interaction system, wherein the formula is as follows:
wherein the human controls the gainAndusing measured average values, or the same values as the robot controller gains, i.e.The superscript symbol v represents the estimated value;
step 3.2: using an intention recognition method based on surface electromyography signals, or by internal model parameterizationAnd estimating, wherein the expression is as follows:
wherein the superscript symbol T represents transposition, and θ is the virtual target position of the person being calculatedThe vector of parameters of (a) is, t represents time, m is a predetermined parameter, and thereforeIs a quantity that is determined by the internal model parameters and varies with time;
state vector using upper limb exoskeleton robot and human interaction systemThe extended model is obtained after substituting the formula (5):
where φ represents: state vector of upper limb exoskeleton robot and human interaction system, v ∈ N (0, E [ v, v ]T]) Is the system noise, i.e., mean 0, variance E [ v, vT]Gaussian noise of (2);
step 3.3: measuring the position and the speed of the end point of the robot and the interaction force with a human through a sensor to obtain a measurement vector of the upper limb exoskeleton robot and the human interaction system:
wherein, mu is N (0, E [ mu, mu ]T]) Is the environmental measurement noise, i.e., the mean is 0 and the variance is E [ mu, mu ]T]Gaussian noise of (2);
step 3.4: calculating an extended state estimate of the robot using the system observer:
wherein Λ represents an estimated value; z represents a measurement vector of the upper limb exoskeleton robot and the human interaction system;
linear quadratic estimation gain K-PHTR-1P is a positive definite matrix obtained by solving the ricatt differential equation:
wherein the noise covariance matrix Q ≡ E [ v, v ≡ E ≡ VT],R≡E[μ,μT]And a denotes a system matrix, and is substituted into equation (11) and expressed as follows:
5. the method for controlling intention assimilation of upper limb exoskeleton robot based on surface electromyography signals as claimed in claim 4, wherein interaction between human and robot is performed through relations τ and τ between human and robothTo determine:
when τ is τhRepresenting assistance of a robot using a human virtual target, the robot follows its original target τr;
When τ is 2 τr-τhWhile, the robot imposes its own target by eliminating the human target from the upper extremity exoskeleton robot and human interaction system;
interactive behavior assimilation from the estimated target position of the human target design robot using the following formula:
τrrepresenting an original target position of the upper limb exoskeleton robot; and lambda represents a hyper-parameter for adjusting the original target position and the human target position of the upper limb exoskeleton robot, and is dynamically adjusted according to the tail end position x.
6. The utility model provides an upper limbs ectoskeleton robot intention assimilation control system based on surface electromyogram signal which characterized in that includes:
module M1: establishing an upper limb exoskeleton robot dynamic model by using a Kenn method;
module M2: performing intention recognition through a surface electromyogram signal based on a dynamic model;
module M3: the intention assimilation control is performed by the virtual object.
7. The system for controlling the ideographic assimilation of an upper limb exoskeleton robot based on surface electromyography of claim 6, wherein the module M1 comprises:
module M1.1: there is no relative motion between the robot, the person and the object, and the robot and the person together manipulate the object, the object satisfying the dynamic equation:
wherein,as the second derivative of the position coordinates of the object with respect to time, f and uhIs the force of the robot and person on the object, MoIs a mass matrix of the object, GoIs the weight of the object;
module M1.2: establishing an upper limb exoskeleton robot dynamics model by using a Kenn method to obtain a joint space dynamics equation when the upper limb exoskeleton robot with n degrees of freedom is in contact with the environment:
wherein q is the joint coordinate of the robot, tauqFor control input, JT(q) is the Jacobian matrix, Mq(q) is the robot inertia matrix,is the Coriolis and centrifugal torque, Gq(q) is the moment of gravity;
and converting into a robot operating space to obtain a kinetic equation:
Mr、Cr、Grrespectively representing an inertia matrix, a Coriolis force and centrifugal force matrix and a gravity matrix of the upper limb exoskeleton robot under a Cartesian space coordinate system, and symbolsRepresenting a pseudo-inverse of the matrix;
module M1.3: simultaneous equations (1) and (3) are obtained to obtain the combined kinetic equation of the object and the robot:
M≡Mo+Mr,G≡Go+Gr,C≡Cr…………(5)
m, C, G respectively representing inertia matrix, Coriolis force and centrifugal force matrix and gravity matrix of the upper limb exoskeleton robot and human interaction system in a Cartesian space coordinate system;
module M1.4: the position, the speed and the human force of the tail end of the upper limb exoskeleton robot are measured, a robot controller with gravity compensation and linear feedback is adopted, and the expression is as follows:
where τ is the target position of the robot, L1And L2Is a gain corresponding to position error and velocity;
the force of a person acting on an object is modeled as:
wherein L ish,1And Lh,2Control gain, τ, for humanshAnd (5) bringing the formulas (6) and (7) into the formula (5) to obtain the dynamic equation of the upper limb exoskeleton robot and human interactive closed-loop system for the target position of the human:
8. the system for controlling the ideographic assimilation of an upper limb exoskeleton robot based on surface electromyography of claim 6, wherein the module M2 comprises:
module M2.1: collecting electromyographic signals of wrists, forearms and elbows of a person through an electromyograph;
module M2.2: filtering, data segmentation and feature extraction are carried out on the collected electromyographic signals, and feature extraction is carried out according to waveform types, so that the extracted features correspond to different intention categories;
module M2.3: training and predicting by using a multi-criterion linear programming in a database and combining a classification method of an online random forest;
module M2.4: during model prediction, the prediction category of each base classifier is compared with the corresponding confidence coefficient and a preset threshold value to determine whether the base classifier votes, finally, a Boost algorithm is used for collecting voting results of all the base classifiers and carrying out weighted summation to find the prediction category with the largest votes, and when the votes are larger than the mean value, the activity intention is output.
9. The system for controlling the ideographic assimilation of an upper limb exoskeleton robot based on surface electromyography of claim 7, wherein the module M3 comprises:
module M3.1: by a virtual target of a personEvaluating the influence of human on the dynamics of the upper limb exoskeleton robot and the human interaction system, wherein the formula is as follows:
wherein the human controls the gainAndusing measured average values, or the same values as the robot controller gains, i.e.The superscript symbol v represents the estimated value;
module M3.2: using methods of intention recognition based on surface electromyographic signals, or byInternal model parameterization pairAnd estimating, wherein the expression is as follows:
wherein the superscript symbol T represents transposition, and θ is the virtual target position of the person being calculatedThe vector of parameters of (a) is, t represents time, m is a predetermined parameter, and thereforeIs a quantity that is determined by the internal model parameters and varies with time;
state vector using upper limb exoskeleton robot and human interaction systemThe extended model is obtained after substituting the formula (5):
where φ represents: state vector of upper limb exoskeleton robot and human interaction system, v ∈ N (0, E [ v, v ]T]) Is the system noise, i.e., mean 0, variance E [ v, vT]Gaussian noise of (2);
module M3.3: measuring the position and the speed of the end point of the robot and the interaction force with a human through a sensor to obtain a measurement vector of the upper limb exoskeleton robot and the human interaction system:
wherein, mu is N (0, E [ mu, mu ]T]) Is the environmental measurement noise, i.e., the mean is 0 and the variance is E [ mu, mu ]T]Gaussian noise of (2);
module M3.4: calculating an extended state estimate of the robot using the system observer:
wherein Λ represents an estimated value; z represents a measurement vector of the upper limb exoskeleton robot and the human interaction system;
linear quadratic estimation gain K-PHTR-1P is a positive definite matrix obtained by solving the ricatt differential equation:
wherein the noise covariance matrix Q ≡ E [ v, v ≡ E ≡ VT],R≡E[μ,μT]And a denotes a system matrix, and is substituted into equation (11) and expressed as follows:
10. the system for controlling assimilation of upper limb exoskeleton robot based on surface electromyography signals of claim 9, wherein interaction between human and robot is performed through the relations τ and τ between human and robothTo determine:
when τ is τhRepresenting assistance of a robot using a human virtual target, the robot follows its original target τr;
When τ is 2 τr-τhWhile, the robot imposes its own target by eliminating the human target from the upper extremity exoskeleton robot and human interaction system;
interactive behavior assimilation from the estimated target position of the human target design robot using the following formula:
τrrepresenting an original target position of the upper limb exoskeleton robot; and lambda represents a hyper-parameter for adjusting the original target position and the human target position of the upper limb exoskeleton robot, and is dynamically adjusted according to the tail end position x.
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