Bio Mech Presentation.

7/29/2019 Bio Mech Presentation.

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Human Movement Biomechanics

and BiomechatronicsProf. Kamran Iqbal

University of Arkansas at Little Rock

Little Rock, Arkansas, [email protected]


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Biomechatronics

Biomechatronics is the interdisciplinary study of biology,mechanics and electronics. It focuses on the research and

design of assistive and diagnostic devices for patients with

disorders of the neuromuscular-skeletal system.

Biomechatronics

is a contraction of biomechanics andmechatronics. [Its] central focus is on the function and

coordination of the human motion apparatus, and the design

of assistive devices for its support. Examples are assistive

devices like an orthosis, prosthesis or functional electrical

stimulation of muscles. The goal is to provide some functionto patients with functional deficiencies.

From TU Delft, Netherlands


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Biomechatronics

Our mission is to develop wearable robots that improvehuman mobility, in particular for individuals whose strength

and coordination have been affected by amputation, stroke,

cerebral palsy, or aging. At present, we are studying ways to

improve stability and energy efficiency using robotic

prostheses and exoskeletons. We believe appropriate

mechanical assistance can not only restore function, but

enhance performance beyond typical human limits.

Experimental Biomechatronics Lab at Carnegie-Mellon University


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Biomechatronics

MIT media lab


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Course Goals

To explore biomechanical and neuro-scientific principlesgoverning human movement

To learn how biomechatronic devices and prostheses can help

amputees regain motor skills


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Biomechatronics

Credit: D. Naidu, Int J Adv Robotic Sys, vol. 9, InTech Pub. 2012


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Biomechatronics

Biomechatronics combines the knowledge of biomechanicsand biological movement control to design human

rehabilitation and augmentation technologies.

Typical application areas in biomechatronics include:

Prosthetic arms and legs Orthotics or assistive technologies

Exoskeletons

Rehabilitation robots

Neuroprosthesis

http://www.robaid.com


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Biomechatronics devices

Upper extremity prostheses Transradial/ prosthetic hand

Prosthetic arm

Lower extremity prostheses

Trans-tibial/ankle-foot prostheses

Transfemoral prosthetic leg

Wheel-chair mounted assistive robotic arms

Rehabilitation and training robots

Exoskeletons

Neuro-prostheses (FES systems)

Neuromodulation

drop foot stimulator


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Biomechatronics Closely Related Fields

Bioengineering Bioengineering integrates physical, chemical, ormathematical sciences and engineering principles for the study ofbiology, medicine, behavior, or health.

Biomechanics the field of study which makes use of the laws ofphysics and engineering concepts to describe motion of bodysegments, and the forces which act upon them

Bionics

the application of methods and systems found in nature to

the study and design of engineering systems and moderntechnology

Neural Engineering the merger of systems neurophysiology andengineering in approaches that link brain activity with man-madedevices to replace lost sensory and motor function

Rehabilitation Technology

systematic application of technologies,engineering methodologies, or scientific principles to meet theneed of and address the barriers confronted by people withdisabilities

Credit: http://www.aimbe.org/resources/medical-biological-engineering-glossary/
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Motor Control in Humans


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Central Nervous System (CNS)

The central nervous system includes brain and spinal cord Brain is composed of six regions: cerebral hemispheres,

medulla, pons, cerebellum, midbrain, and diencephalon

The cerebral hemispheres are concerned with perceptual,

motor, and cognitive functions, including memory and emotion


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Motor Regions in the Brain

Premotor cortex. It plays an important role in sensoryguidance; also active in controlling proximal and axial muscles

Motor cortex. It is responsible for generating motor neuron

commands that activate muscles involved in movement

Posterior parietal cortex. It provides spatial information fortargeted movements


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The Cortico-spinal Tract

Corticospinal tract is the main information highway (backbone)of the CNS that contains about one million axons; about 40% of

the corticospinal neurons originate in the motor cortex

The descending motor information carried in the corticospinal

tract is modulated by sensory, proprioceptive, tactile, and

visual information that contributes to movement accuracy

In addition, other motor regions of the brain, such as the

cerebellum and basal ganglia, also modulate motor neurons to

ensure smooth execution of movements


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The Corticospinal Tract


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Somatosensory and Motor Homunculus

The homunculus illustrates the location and amount of corticalarea dedicated to a particular sensory/motor function


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The nerve cell

A neuron has four morphologically defined

regions:

The cell body, that contains the nucleus and

the genetic information (DNA)

Dendrites, for receiving signals from other

neurons

The axon, which projects over long distances

(up to 3 m) to target cells

Presynaptic nerve terminals, for release ofneurotransmitters at synapses with targets


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Action Potentials

Action potentials are nerve impulses used by the CNS toreceives, analyzes, and conveys information

A typical action potential has an amplitude of 100 mV and a

duration of about 1 ms

Action potentials are regenerated at regular intervals and areconducted down the axon at rates of 1100 m per sec

Hodgkin and Huxley 1939


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The Synapse

An average neuron forms more than 1000 synaptic connections Two basic forms of synaptic transmission are:

An electrical transmission that allows the rapid and synchronous

firing of interconnected cells

A chemical transmission that releases a neurotransmitter fromthe presynaptic neuron that binds to specific receptors in the

postsynaptic cell membrane

A peripheral synapse occurs at the junction of motor neuron

with muscle fibers; a single muscle fiber is innervated by just

one motor neuron


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Peripheral Nervous System

The peripheral nervous system consists of sensory and motorneurons leading to and from the spinal cord

The sensory neurons conduct information from the periphery to

the central nervous system

The motor neurons convey central motor commands to the

muscle fibers


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Sensory Neuron

Nerve endings from sensory neurons transforms a physicalstimulus (such as a stretch) into electrical activity in the cell


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Motor Neurons

Motor neurons conveys motor commands to the skeletalmuscle fibers; they receive multiple inputs:

recurrent excitatory inputs from other motor neurons

both excitatory and inhibitory inputs from interneurons

excitatory input from the primary sensory neurons inhibitory input from Renshaw cells


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Hierarchy of the Motor Apparatus

The sensorimotor modalities are hierarchicallyorganized in the CNS

At the lowest level, the spinal cord, contains neuralcircuits that mediate reflexes and perform rhythmicautomatism (phasic movements)

The brain stem integrates visual, vestibular, andsomatosensory information to mediates posture, andcontrol head and eye movements

The primary motor cortex regulates corticospinal andother motor tracts; the premotor areas mediatecoordinating and planning of complex movements

The cerebellum compares descending signals withafferent signals and updates movement if needed(afferent copy)

Spinal cord

Brain stem

Primary

motor cortex

Cerebellum


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Spinal Reflexes

A reflex arc is established when afferent axons from a sensoryreceptor make direct excitatory connections to motor neurons

innervating the same muscle

Image credit: http://classes.midlandstech.edu/carterp/Courses/bio210/chap11/lecture1.html
http://classes.midlandstech.edu/carterp/Courses/bio210/chap11/lecture1.htmlhttp://classes.midlandstech.edu/carterp/Courses/bio210/chap11/lecture1.htmlhttp://classes.midlandstech.edu/carterp/Courses/bio210/chap11/lecture1.html


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Reflex Action

The sequence of events that produces a reflex action

The reflex latency through the spinal cord in the case of

monosynaptic stretch reflex is less than 1 ms


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Tonic Stretch Reflex

ICET 2011 25/63

(Davidoff, 1992)


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Knee-Jerk Reflex


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Central Nervous System (CNS)

The CNS comprises brain and spinal cord

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