Simulink Model of Human’s Elbow Neuromuscular System Tian Bo

Simulink Model of Human’s Elbow Neuromuscular System

Tian Bo


The joint torque which sets human elbow into motion is generated by a separate group of muscles provided for the joint. As the activation of each muscle is determined by a neural input, a neuromuscular system controlling all muscles has to be considered in order to understand human movements. So we should firstly understand the Mechanism of the elbow movement.

What is Elbow Neuromuscular System?


The goal and assumed data

GOALThe goal is to investigate the effects of muscle strength on the relative contributions of four muscles to dynamic elbow motion.

ASSUMED DATAIn order to sample the model, we make some assumed data:1. Elbow moves in a 2-D path.2. There are two muscle in arm, each one’s

origin of force is in the middle of arm.3. Acceleration of gravity G is 9.8067 .4. The drag torque is only happened in

elbow.

What is Elbow Neuromuscular System?

Recommend three books in this area:

<< Introduction to Sports Biomechanics >>---By Roger Bartlett, E & FN Spon in 1997

<<Sports Biomechanics Reducing Injury and Improving Performance >>

---By Roger Bartlett, E & FN Spon in 1999<<Sports Biomechanics The Basics: Optimising Human Performance>>

--- By Anthony Blazevich, A&C Black in 2007



Mechanism of the elbow movement

Basic theory

Kinematical equation

second-order

linear time invariant

differential equation methods

Newton's laws of motion

Dynamical equation

Newton's laws of motion

NomenclatureSimulink Model of Human’s Elbow Neuromuscular System

:Vector from origin to wrist

:Vector from origin to elbow

:Vector from elbow to wrist

:Shoulder joint angle

:Elbow joint angle

:Lengh from origin to elbow

:Lengh from elbow to wrist

:Shoulder joint velocity vector

:Elbow joint velocity vector

: Shoulder joint acceleration vector

: Elbow joint acceleration vector

: C1 Centrobaric acceleration vector in X : C1 Centrobaric acceleration vector in Y : C2 Centrobaric acceleration vector in X : C2 Centrobaric acceleration vector in Y


Kinematical equation model


scalar equation

derivation operation

corresponding to X and Y

derivation operation



Suppose if the center of gravity is in the middle of forearm, then obtained following equation



Dynamical equation


Dynamical equation

Forearm &1


Dynamical equation

Forearm &2


Dynamical equation

Actual load


Simultaneous

matrix from the 6 dynamical equations and 8 kinematical equations

Simulink® is an environment for multidomain simulation and Model-Based Design for dynamic and embedded systems. It provides an interactive graphical environment and a customizable set of block libraries that let you design, simulate, implement, and test a variety of time-varying systems, including communications, controls, signal processing, video processing, and image processing.

--- www.mathworks.com

What is Simulink?Simulink Model of Human’s Elbow Neuromuscular System

Solving matrix equation by calling matlabSimulink Model of Human’s Elbow Neuromuscular System

Code in function mdlOutputs % Rectangular array declarations

% A rectangular array


Code in function mdlOutputs % B rectangular array


Code in function mdlOutputs

% solve the equations fff=inv(a)*b; %output the result outfff(1)=fff(1); outfff(2)=fff(2); outfff(3)=fff(7); outfff(4)=fff(8); outfff(5)=error; sys=outfff;

Add this function to a s-function model (sfuntmp1. m ).

Simulink model: s-functionSimulink Model of Human’s Elbow Neuromuscular System

mdlInitializeSizes ： Specify the number of inputs, outputs, states, parameters, and other characteristics of the S-function;

mdlDerivatives ： Compute the S-function's derivatives ;

mdlUpdate ： Update a block's states ;

mdlOutputs ： Compute the signals that this block emits;

mdlGetTimeOfNextVarHit ： Initialize the state vectors of this S-function ;

mdlTerminate ： Perform any actions required at termination of the simulation;

Simulink modelSimulink Model of Human’s Elbow Neuromuscular System

OutputSimulink Model of Human’s Elbow Neuromuscular System

Next stepSimulink Model of Human’s Elbow Neuromuscular System

1. This system is just a sample of elbow system, it’s far away from the truly world.And need to rebuild the model and add more parameter into the system.

2. Need to limit the elbow moving angle in next step.

3. Actually do the real model neuromuscular system.

ReferencesSimulink Model of Human’s Elbow Neuromuscular System

[1] Timotej Kodek, Marko Munih, An analysis of static and dynamic joint torquesin elbow flexion-extension movements, Simulation Modelling Practice and Theory 11 (2003) 297–311[2] Tadashi Kashima, Yoshihisa Isurugi, Masasuke Shima, An optimal control model of a neuromuscular system in human arm movements and its control characteristics, Artif Life Robotics (2002) 6:205-209[3] AME Project #1 test, A university’s class project[4] Vague, 单关节平面机器人动力学仿真[5] Sybert Stroeve, Neuromuscular control model of the arm including feedbackand feedforward components, Acta Psychologica 100 (1998) 117±131[6] Tsukasa Kanchiku, James V. Lynskey, Neuromuscular electrical stimulation induced forelimb movement in a rodent model, Journal of Neuroscience Methods 167 (2008) 317–326[7] N. Lan and T. Murakata, A REALISTIC HUMAN ELBOW MODEL FOR DYNAMIC SIMULATION, Dept. of Biomedical Engineering, University of Southern California

ReferencesSimulink Model of Human’s Elbow Neuromuscular System

[8] Roger Bartlett, Introduction to Sports Biomechanics, E & FN Spon in 1997[9] 姚俊 , 马松辉 , Simulink 建模与仿真 , 西安电子科技大学出版社 2004[10] Patrick J. Schimoler, DESIGN OF A CONTROL SYSTEM FOR AN ELBOW JOINT MOTION SIMULATOR , University of Pittsburgh, 2005 [11] 李良标 , 运动生物力学 , 北京体育学院出版社 1991

Simulink Model of Human’s Elbow Neuromuscular System Tian Bo

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