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what standard is used for Anthropometric data
BS PP 7310
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Guidelines for standard deviation from mean (and percentage of population within limits) when designing for
cheap economy
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Guidelines for standard deviation from mean (and percentage of population within limits) when designing for
premium economy
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Guidelines for standard deviation from mean (and percentage of population within limits) when designing for
1st class
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Guidelines for standard deviation from mean (and percentage of population within limits) when designing for
safety
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Guidelines for standard deviation from mean (and percentage of population within limits) when designing for
critical safety
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how do calculate standard deviation for 95%le?
why use 95%le?
- s=(95%le-5%le)/3.29
- s=(95%le-50%le)/1.645
- can be calculated from 5% and/or 95% points
- data often available for 5% and 95% points
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how do calculate number of std. dev. from mean?
- z=|X-L|/s
- x - mean
- L - value in question
- s - standard deviation
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what human height intervals should be used when designing
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is a standard anthropometric data table suitable for all applications? why?
- no
- the data are usually only for young, healthy adults. people put on weight when they age, different designs may appeal to different demographics with different data
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7 ergonomics factors to consider in car design
- driver visibility
- mirrors
- steering ratio
- pedal design
- seat design
- wheel changing
- dashboard
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what to consider in car design w.r.t.
driver visibility
- pillars (esp. A pillars) give potentially dangerous blind spots. minimise these
- height is a trade off - low = better aero performance, high = better visibility
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what to consider in car design w.r.t.
mirrors
- flat interior mirror gives true distance perception
- curved side mirrors give wider FOV (but vehicles are closer than they appear)
- blind spots behind driver's shoulders. minimise these with careful mirror design
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what to consider in car design w.r.t.
steering ratio
- racing cars - low ratio - v responsive. can be dangerous for normal cars
- balance to be found - too high, not responsive; too low, too responsive
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what to consider in car design w.r.t.
pedal design
- enough movement for precision, within range of a foot
- sideways spacing designed for extremes of foot size
- enough resistance to spring back, but not too hard for long distances
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what to consider in car design w.r.t.
seat design
- minimise vibration imparted to driver
- allow adjustment
- crash protection - including head support
- bucket shape - prevent sideways movement
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what to consider in car design w.r.t.
wheel changing
- easy to use jack and spanner (forces and alignment)
- easy to assemble wheel (including alignment)
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what are the main goals of displays
- alert operator to danger in a clear way
- minimise distraction
- maximise speed of communication
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conventions for colour and flashing (with examples)
- slow flashing light - warning (low outside temp)
- fast flashing light - danger (overheating engine)
- red - danger (open door)
- yellow - warning (low fuel)
- green - safe (green light)
- fast beep - danger (parking sensor)
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guidelines for good man-machine interface
- use iconic images
- optimal proximity (e.g. radio controls on steering wheel to keep hands there)
- sensible orientation - controls should follow direction of movement (e.g. turn indicator)
- size - easy to read
- good grouping - have controls in logical groups
- clear emergency and switch off buttons
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why include a central braking light?
- rear lights shine red when braking
- not v clear at night with tail lights on
- most cars have central top brake light that only comes on when braking
- improves safety by better distinguish between braking and not braking
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what hapen 1 july 2002, uberlingen, germany?
(man-machine interface case study)
- passenger jet + cargo jet flying at 36k feet on collision course
- ATC was working 2 workstations at the same time, didn't realise problem in time - failed to keep the aircraft at safe distance from each other
- only realised <1minute before accident
- contacted passenger jet, instructed pilot to descend 1k feet to avoid collision with cargo plane.
- plane starts to descend, but traffic collision avoidance system (TCAS) instructed passenger plane to ascend, while instructing cargo plane to descend.
- if both planes followed TCAS instructions, all would have been groovy. but it wasn't to be
- cargo plane pilot followed TCAS and started descending
- passenger jet pilot had to decide between following ATC or TCAS instructions.
- because already commenced descent, as ordered by ATC, they continued descent.
- thus both planes were descending together and collided :(
enquiry
- ATCs guilty of negligence
- controller shouldn't have been operating 2 stations
- unfortunate russian culture of giving preference to verbal rather than computer instructions.
- pilots need more guidance on responding to conflicting instructions
- ATC need more guidance on giving clearer instructions
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Vibration data (ISO 2631):
frequency bands, and effects
- 0.1-20Hz - instability and difficulty balancing
- 0.1-0.6Hz - motion sickness
- 4-10Hz - Trunk resonates (damage to organs and spine)
- 30 - Head and neck resonate
- 60-100Hz - eyes vibrate, blurred vision
- 10-18Hz - urge to urinate
- 13-20Hz - speech disturbed
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use of vibration level charts?
- give exposure limit - halfway towards pain threshold
- find fatigue decreased proficiency boundary - design for working
- find reduced comfort boundary - design for comfort
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how do adjust strength data to fit certain demographics?
multiply by each relevant factor:
use factor
- one off - 1
- occasional - 0.6
- frequent - 0.3
- continuous - 0.15
age factor
- 20 - 0.9
- 30 - 1
- 45 - 0.9
- 60 - 0.8
gender factor - female: 0.5
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