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Flashcards in Design Of Controls Deck (23)
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1
Q

For a control that is activated by a small actuation force and has a small range of continuous settings, what type of controls should be used? For a control that is activated by a large actuation force and has 2 discrete settings, what type of controls should be used?

A

Small force, small continuous range:
knob/joystick lever

Large force, 2 settings:
Hand pushbutton/ foot pedal

2
Q

What 2 things should a control be?

A

Appropriate and intuitive to use

3
Q

Over the years, many controls have become standardized. Provide 3 examples of this.

A

Car controls incl. gas, brake, steering controls

Manual lever for aircraft throttle

Lever control for gear shift

4
Q

Provide 3 advantages and 3 disadvantage of using either touch screen or light pens as computer input devices.

A

Advantages:

  • Little training. Pointing is intuitive
  • Good for public environments
  • No moving parts. Robust and sturdy
  • Excellent hand-eye coordination

Disadvantages

  • Maintaining arm extension could induce fatigue
  • Input resolution poor
  • Pointing object partially obscures display
5
Q

What is ‘negative transfer of training?’

A

When a user operates according to previous training with a new or different control scheme, resulting in error

6
Q

What is “control movement stereotypes”? Provide 3 examples. What are the consequences of designing controls that contradicts such stereotypes?

A

Control Sterotypes are learned behaviours, ideas that controls should behave in certain stereotypical ways. Example: tap to the left for hot water. Turn a knob away from the door jamb to open it, light swithc up to turn it on (in US).

If you don’t follow these you might encounter user errors, which may lead to a product not selling, or people dying

7
Q

What is a “one-to-one” correspondence? Provide an example of a “one-to-one” correspondence and a non “one-to-one” correspondence.

A

1-to-1 correspondence is when the motion of an element matches the motion of the control. This is highly desirable. Example: Light dimmer switch. Brightness up= slide dimmer up

Example of not 1 to 1: Push lever FORWARD in forklift, and the lifting beams go DOWN

8
Q

What is control response compatibility? What are the 5 levels of compatibility? Give a sentence or example to describe/explain each.

A

• Compatibility refers to the relationship of stimuli and responses that are consistent with human expectations, resulting in decreased errors and faster response time.

Levels:
Conceptual- Is the code meaningful?
Affordance- Perceived property results in the desired action. Alternatively: a control lends itself to the function it performs
Movement- Relation btwn control movement and element movement
Spatial mapping- Physical arrangement of controls and display
Modality- Using same stimulus modality for signal and response

9
Q

Which of the compatibility level does the typical stove top we have in our kitchen violate? How would you redesign the stove top to avoid this incompatibility?

A

Spatial Mapping.

Arrange the controls in a square matching the burner arrangement

10
Q

Provide an example for each mode of control coding

A

Location– turn signal beside steering wheel

Color–Red=danger

Size– Allows distinction when not visible e.g. Making master power button small on laptop-> minimize accidental shutdown

Shape– Making different lever handles diff shapes to be distinguishable without looking. **INCL surface texture

Labelling– “ Push to start”
label explicitly says what control does. Keep design pros in mind. Readability and ease of understanding.

Mode Of Operation– Nature of control (button vs lever etc) or the resistance level btwn similar controls distinguishes btwn them

11
Q

What are the 6 types of control coding?

A

Code By:

  • Location
  • Color
  • Size
  • Shape
  • Labeling
  • Mode of Operation
12
Q

Why is it important to consider illumination level and color stereotypes when coding by color?

A

Illumination affects color and thus code visibility

Stereotypes can influence an operator to act contrary to training, or make training harder to instill

13
Q

If there is a set of controls that you need to activate, but you cannot see it because it is hidden in back of machine, what are 3 ways to code the controls so you will not make a mistake when using it?

A

Code by size, shape, and Mode of operation

14
Q

Explain and provide an example of why it is important to maintain consistency when coding controls.

A

To avoid accidents caused by negative transfer of training

15
Q

What is redundant coding? Why/when should redundant coding be used?

A

Redundancy is combining different dimension of control coding even though one may theoretically suffice. Best used for emergency controls to minimize mistakes/ ensure control is recognized. When designing redundancy, multiple modalities are more effective than multiple dimensions within the same modality

16
Q

What are the 4 recommendations for designing emergency controls?

A
  • Position away from regularly used controls, reduce risk of undesired activation
  • Make emergency controls easy to reach
  • Make emergency controls large and easy to activate
  • Color them RED
17
Q

It is said that one “should locate all control devices for best operator accessibility and strength capability”. Provide some examples of this.

A

The trigger on a gun doesn’t require a lot of force to activate.

The hatch on a submarine door is in the center

bad example: emergency open on subway train is above the door, some cannot reach

18
Q

Why are the 3 factors that affect the performance of a control? Give a sentence to explain how each of these affects performance.

A

Control Size- If too small, or too large, activation is not efficient

Control Response Ratio- Does a lot of movement of control translate to very little movement of element? Other way around?

Control Resistance- Good for providing feedback. Can increase operator responsiveness/ attention

19
Q

What is control-response ratio? What is optimum C/R ratio? What does a high C/R ratio imply? Give an example of a control that has a high C/R ratio.

A

The ratio is the fraction of control movement over response movement.

The optimum ratio gets the desired target with minimal time (minimal adjustment)

A high ratio implies a control that can be finely tuned. Example: Fine adjustment knob on compound microscope

20
Q

What is the purpose of using symbols in manufacturing or product design? Why are symbols preferred over labels?

A

Purpose: To quickly and simply transmit instructions or information. Preferred because they operate across language barriers and can be interpreted more quickly, take less space

21
Q

What are the 3 ways labels can be expressed? Give an example for each. Which is the preferred way and why?

A

Affirmative, Passive, Negative
“Level opens door”
“Door is opened by lever”
“Lever does not turn on AC”

Active is preferred, easiest to interpret in a hurry

22
Q

What are the 4 stages in users processing warning signs? Provide an ergonomics design consideration for each.

A

Stages:

  • Exposure to sign
  • Attention and Processing
  • Comprehension and agreement
  • Selection of Response

Improvements to each:

  • Make it bigger, locate it where visible
  • Cite previous accidents to call attention
  • Employ Wogalters 4 fundamental elements
  • Make the safe choice the easy choice ( that is, outcome or consequences fo making safe choice do not notably inconvenience or cause discomfort)
23
Q

According to Wogalter, what are the 4 fundamental elements in a warning sign? Give an example to illustrate.

A
  • Signal Word
  • Hazard
  • Consequences
  • Instructions

“Caution!
Sexy hunk
Risk of impregnattion
Employ rubber”