The Origin and Development of Ergonomics
Research content of the subject
Human Machine Environment【7】
Product design human scale
Human anatomy dimensions (static dimensions)
Functional size (dynamic size)
Measurement datum
sagittal plane midsagittal plane
Supporting surfaces and clothing
How to apply human body dimensions
Determine the type of product being designed: single limit size or double limit size
Clarify size calculation logic or size comfort conditions
Determine which dimensions of the human body to use
Select human body size fraction
Calculation of base dimensions based on comfort conditions or target logic
Determine the functional correction amount
Right amount of decoration
Posture correction amount
Determine the amount of psychological correction
Minimum functional size = human body size percentile functional correction amount
Add functional size = human body size percentile functional correction amount psychological correction amount
Brain neural network composition
brain neurons sensory neurons motor neurons
cell body dendrite axon synapse
The macro process of human intelligence formation【p41】
Sense organ, thinking organ, effector organ, reaction system
Human intelligence formation process model【p43】
Sense organs (perception systems)
conductive nervous system
Thinking organ (information processing system)
The conversion mechanism formed by human intelligence (i.e. information conversion)
Ontological information to epistemological information (information acquisition)
Epistemology Information to Knowledge (Cognition)
Intelligent strategies for knowledge (decision-making)
Smart strategy to smart behavior (execution)
The formation of human intelligent behavior【p48】
Specific environment Specific goals Problem to be solved
Information refines knowledge to achieve cognition
Knowledge activation into intelligent strategies
Transform into intelligent behavior to solve problems and achieve goals
New goals, new problems, new environment
The expansion of human intelligence and the law of scientific and technological development
mental activity
Human psychology is the subjective reaction of the objective world in the human mind
behavioral response
Behavior is the external manifestation of psychological activities and the state transition of the activity space.
Stimulus S Organism O Response R
Behavior includes both internal motivations and emotions, as well as external behavioral expressions.
basic characteristics of feeling
sensory threshold
upper limit of sensory threshold
differential sensory threshold
adapt
After a sensory organ is continuously stimulated for a period of time, the sensation will gradually decrease or even disappear if the stimulus remains unchanged. This phenomenon is called adaptation.
interaction
Sensitivity is reduced due to interference from other stimuli
basic properties of perception
Perception is the human brain's overall reflection of objective things and subjective conditions that directly act on the sensory organs.
Feeling reflects the individual attributes of objective things, and perception reflects the overall nature of objective things.
Wholeness, selectivity, understanding, constancy, illusion
Features to note
Various human psychological activities have certain directionality and concentration, which is called attention in psychology.
Pay attention intentionally, pay attention unintentionally
Momentary attention span is generally 7 units (6-8-9)
Strengthen the intensity of environmental stimulation, enhance the variability of environmental stimulation, and use novel and prominent image stimulation
imagination process
The process of using the original image to form a new image in the human brain
Unintentional imagination
thought process
analysis synthesis comparison abstract generalization
divergent thinking focused thinking
creative formation mechanism
Five elements of creativity: knowledge, experience, talent, psychological quality, opportunities
Three driving forces of creativity: creative desire, thinking, practice
The output range of the limbs
The amount of force exerted
Physiological characteristics of human muscles
Force application posture
The maximum pedaling force is generated when the knee is flexed 160 degrees
Force application in different postures of the human body
The decrease in leg muscle strength is more obvious than that of the upper limbs
Avoid static muscle exertion
Static force cannot be avoided
Size less than 15% of the muscle's maximum strength
Simple repetitive movements should not exceed 30% of maximum muscle strength
Design Points
Avoid raising your hands for long periods of time
Both hands operate at the same time Same Opposite
Use a support to support the elbow, forearm or hand when working at a higher position.
Take advantage of gravity
Avoid bending down to lift heavy objects
Straighten your waist and bend your knees
Bending the waist and straightening the knees increases the force in the intervertebral disc
Human-computer information interface【p89】
Informative interface (most important)
visual system
eyes optic nerve visual center
Visual stimulation (light)
The human eye receives wavelengths from 380 nanometers to 780 nanometers
visual organ
The human eye is a sphere with a diameter of 21 to 25 mm
visual function
field of view and sight distance
Horizontal field of view
The limit of the visual field of one eye is 94~104 degrees
vertical plane field of view
Maximum visual acuity 50~-70
in relaxed state
Sitting posture deviation 38
sight distance
Normal viewing distance for people in the operating system
Color vision and color vision
The visual field of white, yellow, blue, red and green decreases in sequence.
Dark adaptation and light adaptation
Dark adaptation for 20 to 25 minutes
visual characteristics
From left to right, top to bottom, clockwise (line of sight changes)
Fast movement in horizontal direction (level of fatigue)
Accurate horizontal dimensions (accuracy)
Upper left, upper right, lower left, lower right (observation priority)
Straight contours are more acceptable (acceptance)
Red, green, yellow and white (color identification) black characters on a yellow background, white characters on a black background, white characters on a blue background, black characters on a white background
Physical characteristics of hearing【p97】
Hearing threshold: Within the optimal hearing frequency range, a person with normal hearing can just hear the lowest sound intensity of a sinusoidal pure tone of a given frequency. is called the hearing threshold at the corresponding frequency
No obvious change between 800-1500 Hz
3000~4000 maximum hearing sensitivity
Greater than 6000, sensitivity decreases
Pain threshold: almost independent of frequency
Masking effect:
The phenomenon of one sound being masked by another is called masking
The hearing threshold of one sound is increased due to the concealing effect of another sound, which is called the masking effect
Instrument display design
The relationship between instrument form and misreading rate [p100]
Scales and numbers (the scale pointed by the pointer starts upward)
auditory information transmission device
broadly used
When the signal is simple and brief
When a signal is required to be delivered quickly
When it is not necessary to check the signal after transmission
When signals are only designed for process or temporal events
When the visual burden is too heavy or is not conducive to the transmission of visual information
When the operator is on patrol and needs to interfere with the signal identification
siren
In noisy places, use a sound whose frequency is far away from the noise frequency as a signal to weaken the masking effect.
There should be obvious differences between two or more signals
Use intermittent or changing signals to avoid auditory adaptations
High-power low-frequency signals are required when transmitting remotely or bypassing obstacles.
Hazard signals should be distinguished from other signals or noise by two acoustic parameters and have the same duration
Design of hand manipulator【p110】
The handle adapts to the physiological characteristics of the hand
Handle shape facilitates tactile identification
Meet the needs of human hand scale
Design of foot control operator【p114】
broadly used
Continuous operation is inconvenient with hands
The operating load on the hands is too great
The foot controller has at least 40n of resistance
Foot controller size
The width is the same as the width of the sole of the foot, generally greater than 2.5
Foot pedals are generally designed in a rectangular shape
Control device coding and selection
Design principles of hand-held tools【p128】
anatomical factors
Avoid cervical spine loading
Keep your wrists straight
Avoid repetitive finger movements
handle design
Diameter (30~40mm for strong grip, 8~16mm for precision grip)
Human-machine interface for visual display of terminal work positions [p137]
Close working space【p141】
Working surface height
Generally, the height of the working surface is 5 to 10 cm below the elbow.
General principles for workplace layout
Frequency of use principle
The human body's adaptability to the environment
environment
Thermal environment lighting noise vibration dust toxic substances
Factors affecting the thermal environment:
Air humidity
High relative humidity above 80%
Relative humidity below 30%, low humidity
thermal comfort
subjective evaluation basis
Requirements for light environment
Bright vision lighting is mainly functional
Mood lighting for comfort
Basic principles of design
Reasonable average level of illumination. Brightness and illumination should not be too high or too low, nor should they be too consistent to produce monotony.
The direction and diffusion of light should be reasonable to avoid disturbing shadows, but necessary shadows can be retained to give the object a three-dimensional feel.
Do not let light shine directly into your eyes to avoid glare. Only reflected light enters your eyes.
The light color of the light source is reasonable
Lighting and color coordination
Don’t ignore the constraints of economic conditions
Illuminance and illuminance distribution of lighting
The impact of noise on people
Above 90 decibels there is a significant impact
Vibration characteristics of the human body
Low frequency area High frequency area
Human-machine system reliability
Human reliability and mechanical reliability (Rs=Rh×Rm)
Classification of levels of brain consciousness
external factors of human error
The sequence of stages of the accident
Safety device design
Use induction to control safety distance
Automatic shutdown device
Overall design principles
Design related to body size
Design related to body posture, muscle strength and body movements
Design of signal displays and controllers
Human-machine function distribution
Flexibility to create sudden changes is borne by people
Fast, precise, mechanical, regular, long time, cumbersome, borne by machinery
Human-machine matching
Controllers and Human Movement
Human-machine environment
Comprehensive integration method
Expert system, data and information system, computer system = a highly intelligent human-machine integration system
Comprehensive integrated seminar hall system
Expert system, machine system, knowledge system = virtual workspace
Simple intelligent system comprehensive design model
Perception layer, decision-making layer, execution layer
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