Lecture 1 - Introduction to Control Flashcards

1
Q

vestibulo-ocular reflex (VOR)

A

eye movement reflex that stabilizes imagines on the retina during head movement

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2
Q

control theory + genetics =

A

systems biology

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3
Q

control theory has been applied to which fields?

A
  • motor physiology - gene regulatory networks
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4
Q

define: plant

A

thing we want to control/influence

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5
Q

___ receives input and sense commands to the plant

A

controller

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6
Q

types of control

A
  1. open loop 2. feedback 3. internal feedback
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7
Q

open loop

A

input -> controller -> plant -> outcome

  • controller receives no feedback
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8
Q

Another name for open-loop

A

ballistic control

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9
Q

Limitation of open-loop control

A

cannot recover from malfunctions or disturbances happening at the plant

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10
Q

Feedback control

A

Control system which monitors its own progress and adjusts its commands accordingly

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11
Q

Examples of feedback control:

  1. Mechanical
  2. Biological
A
  1. Heat seeking missile
  2. balance
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12
Q

What body parts do we use for balance/posture?

A
  • Inner ears
  • Vision
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13
Q

Limitation of feedback control

A
  • disturbance is too great
  • Delay around the loop
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14
Q

In feedback control, ____ send information about outcomes back to controller.

A

Sensors

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15
Q

Solution to feedback delay

A

Use plant models and internal feedback

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16
Q

define: plant model

A
  • Mimic the actions of the plant (what the plant is doing or what it is about to do)
  • Send info to controller with little delay (located close to controller)
17
Q

Disadvantage of plant model

A

If the model is inaccurate or ignores some disturbances in the real plant, the system malfunctions

18
Q

Information about how to move your eyes come from _____ when head is moving.

A

Inner ear

19
Q

____ measures head rotation and is responsible for VOR

A

inner ears

20
Q

VOR’s plant is…

A

the eyeballs

21
Q

VOR’s input comes from…

A

semicircular canals of the inner ear (there are 3 canals – x, y and z axis plane)

  • each canal is responsible for firing afferent nerve fibres at a rate proportinal to the rotary head velocity in the plane of that canal
22
Q

The semicircular canals sense… (VOR)

A

rotary head velocity

23
Q

The semicircular canals are called _____ organs because they lin within a chamber called the _____ in the inner ear

A
  • vestibular organs
  • vestibulum
24
Q

Why is the VOR called VOR?

A

it uses information from vestibular sensors to control the eyes

25
Q

Pathway for VOR control

A
  1. Semicircular canals
  2. Primary vestibular neurons (in vestibular gangion)
  3. Secondary vestibular neuronsneurons (in vestibular nucleus)
  4. Motoneurons (in cranial nerve nuclei 3, 4, 6)
  5. Eye muscles
26
Q

How many cranial nerves do we have on each side of the brain?

A

12

27
Q

Which cranial nerves do the VOR involve?

A

3, 4, 6

28
Q

Streptomycin is a…

A

antibiotic

29
Q

VOR is ____ control. Why?

A

open-loop

head velocity→controller→eyes→eye position

Since the inner ear regulates VOR, it can’t “see” if the images are actually stable on the retina

30
Q

VOR: eye velocity should =

A
  • head velocity
31
Q

Plant equation (gives eye velocity)

A

dx/dt = (u - kx) / p

  • v = head velocity
  • u = controller / command
  • x = eye position
  • k, p = constant (mechanical properties of the eye muscles)
32
Q

What part of the plant equation does the controller alter? What does it want it to equal?

A
  • Alters u
  • dx/dt = -v
33
Q

The controller’s law is called…

A

control law

34
Q

Control Law

A

u = kx - pv

  • Brain sends this command to the eye muscles to keep retinal images stable
35
Q

control law keeps head velocity = -eye velocity provided that…

A

k and p (constants) used by the controller and the plant are the same

36
Q

What happens if the controller’s p’ value is 80% of the plant’s p value? (p’ = 0.8p)

A

eye velocity is 80% as large as head velocity (dx/dt = 0.8v)

  • On the graph, amplitude changes
37
Q

What happens if the controller’s k’ value is 50% of the plant’s k value? (k’ = 0.5k)

A

eye velocity is out of phase with head velocity

  • On the graph, displacement in the x direction changes
38
Q

In general, a control system only funtions properly if…

A

Its controller is tuned to its plant

  • k’ = k
  • p’ = p
39
Q

VOR’s controller involves several brain structures, but its core is _______

A

brainstem neurons