Human Factors Research

1
Human Factors Research

• Professor Michael J Griffin

2
What is Human Factors?

• Human Factors seeks to enable engineers to take
  account of the human element in
• machine design,
• working and living environments, and
• systems organization.

3
It is easier to bend metal than twist arms!
Engineering or Human Factors
4
Human Factors - Scope
Concerns human relations with machines and the
environment. Aids the assignment of
appropriate roles to humans and machines in
systems. Involves the consideration of
operators, maintainers and users of systems.
Concerns the development of working and living
conditions that are comfortable, efficient and
safe.
5
Different types of stressor
6
Simple model
HUMAN
7
Simple comfort model
inter-subjectvariability
Comfortevaluation
Environment
HUMAN
intra-subjectvariability
8
Simple performance model
inter-subjectvariability
Activityevaluation
Environment
HUMAN
intra-subjectvariability
9
Simple health and safety model
inter-subjectvariability
Health andsafety evaluation
Environment
HUMAN
intra-subjectvariability
10
Independent variables
seating sounds vibration
acceleration shocks thermal visual
smells fumes cleanliness food
drink privacy toilets travel information
11
Independent variables

• seating (shape, size, ventilation, etc.)
• sounds (level, frequency, duration, etc.)
• vibration (magnitude, frequency, direction,
  duration, etc.)
• acceleration (magnitude, direction, duration,
  etc.)
• shocks (magnitude, duration, shape of shock,
  direction, etc.)
• thermal (temperature, humidity, airflow,
  clothing, etc.)
• visual (luminance, contrast, area, location,
  etc.)
• smells, fumes (strength, duration, etc.)
• cleanliness (appearance, etc.)
• food drink (type, frequency, cost, etc.)
• privacy (visual, auditory, etc.)
• toilets (size, cleanliness, etc.)
• travel information (route, punctuality,
  predicted delays, etc.).

12
Summation of independent variables?
seating
sound
vibration
thermal
visual
13
Summation of dependent variables!
14
Contributions to understanding human response
15
Contributions to understanding human response

• Experimental studies
• Laboratory
• Simulation
• Field

16
Approach

• Provide practical guides to existing methods
• Assess current methods for the rail environment
• Improve methods where appropriate
• Field studies
• Simulation studies
• Fundamental studies.

17
Design Guides

• Seating
• Vibration
• Motion sickness
• Noise
• Thermal

18
Seat transmissibility
Transmissibility
19
Seat Effective Amplitude Transmissibility SEAT
ride on seat

x 100
S E A T
ride on rigid seat
20
Transmissibilities and SEAT values of 10 train
cushions
3
Spring cushion
Spring case A
Spring case B
Foam A
Foam cushion
Rubberised hair
2
Foam B
Foam C
Transmissibility
60 mm foam
30 mm foam
1
0
0
25
5
10
15
20
Frequency (Hz)
21
What makes a comfortable seat?
22
Pressure distribution beneath buttocks
23
Pressure distribution beneath buttocks
1.8 - 2.0
1.6 - 1.8
1.4 - 1.6
1.2 - 1.4
1.0 - 1.2
0.8 - 1.0
0.6 - 0.8
0.4- 0.6
0.2 - 0.4
0 - 0.2
(N.cm-2)
24
Seating Design Guide

• Introduction
• The User Population
• Seat Measurements
• Additional Considerations for Driver Seating
• Static Seat Comfort Testing
• Dynamic Response of Seat
• Glossary
• References
• Bibliography
• Appendices.

25
Optimise by prediction, measurement, evaluation,
and subjective evaluation
Measure vibration in vehicle
Predict vibration in vehicle
Vibration assessment
26
Measurement Class 442 Wessex Express
27
Measurement Class 442 Wessex Express
28
Evaluation motion in 9 axes
29
Evaluation motion in 9 axes
zb
yb
0.15
xb
zs
0.1
ys
acceleration (ms-2 r.m.s.)
xs
0.05
zf
0
yf
xs
ys
zs
xb
yb
zb
xf
yf
zf
Axis
xf
30
Motion sickness in tilting trains
31
Motion sickness

• Effect of roll-compensation of lateral
  acceleration on motion sickness

32
Combined translation and rotation
33
Combined translation and rotation
34
Sickness with lateral oscillation and 100
roll-compensation
0.8
Proportion reaching mild nausea
0.7
0.6
0.5
Uncompensated lateral oscillation
0.4
0.3
0.2
1.4
0.1
0
0.7
Peak acceleration
0.05
(m/s²)
0.0315
0.08
0
0.2
0.125
0.5
0.315
0.8
Frequency (Hz)
35
Effects of phase lag and phase lead on motion
sickness
3.5
3
0 delay
2.5
14.5 delay
Mean Illness Rating
2
29 delay
1.5
1
29 advance
0.5
0
0
5
10
15
20
25
30
35
40
45
50
Duration (minutes)
36
Motion simulation for studying human responses
12 metres 10 degrees
1 metre vertical
1 metre horizontal
Six-axis simulator
37
Subjective Measures

• Questionnaires rating
• Sensation
• Comfort
• Stickiness
• Preference
• Acceptability
• Satisfaction

38
Comfort trials
39
Measurements in driver cabs
40
Summary

• Optimising travel environments requires knowing
• Causes of displeasure in travellers (e.g.
  discomfort)
• Causes of displeasure in non-travellers (e.g.
  annoyance).
• How desirable and undesirable features can be
  controlled
• Factors influencing comfort on trains include
• Oscillations (vibration and low frequency motion)
• Noise
• Seating comfort
• Thermal environment
• Lighting

41
Methods of evaluating human responses based on
ISVR research
ISVR Contributions to International Standards
Frequency weightings Wb
(ISO2631, ISO8041, BS6841, BS7085, BS 7482-3)
Wc, Wd, We (ISO2631, ISO8041,
BS6841) Wf (ISO2631, ISO8041,
BS6841)
Dose and averaging methods
VDV, eVDV, and r.m.q. (ISO2631, ISO8041, BS6841)
MSDV (BS6841, DIS2631)
Evaluation procedures SEAT
values (ISO10326-1, EN30326-1)
VWF scoring (HSE and company standards, ISO 5349)
Coordinator of EU projects
VINET, TESTOPS, VIBSEAT, VIBRISKS, VIBGUIDE
Participant in various other EU projects (e.g..
FACT, COMPASS)
42
Rail applications of Human Factors Research

• Comfort
• improved prediction of vibration discomfort
• multi-input noise seating non-linearity
• Activities
• reading writing drinking use of computers
• postural stability
• Health
• crew exposure EU Physical Agents (vibration)
  Directive
• Motion sickness
• tilting trains
• Seating
• dynamic prediction optimisation testing to
  standards
• static design guide testing

43
consultancy
research
Current understanding
research
research
44
consultancy
research
Current understanding
research
research
45
Human Factors Research

• Professor Michael J Griffin