What Is Occupational Ergonomics?

Ergonomics is a multi-disciplinary interdisciplinary subject. The core problem of research is the coordination between human, machine and environment in different tasks. The research methods and evaluation methods involve psychology, physiology, medicine, anthropology, In the fields of aesthetics, design and engineering technology, the purpose of research is to guide the design and transformation of working appliances, working methods, and working environment through the application of knowledge in various disciplines, so that operations are efficient, safe, healthy, comfortable, etc. Several aspects have been improved.

ergonomics

Ergonomics originates from different disciplines and different fields, and is oriented to research and application in a wider range of fields, because the problem of human-machine environment is a universal problem in human production and life. The origin of different disciplines and regions has also caused long-term coexistence of diversified subject names. In English, there are mainly Ergonomics (Europe), Human Factors (United States), etc. In Chinese, there are also "ergonomics", " Ergonomics "and" ergonomics. " China generally regards "ergonomics" as the standard name for this discipline, but the author prefers the term "ergonomics". In comparison, the former indicates that the study of human and ergonomics is the main content of the discipline, but the latter is more capable. Grasping the core of the problem lies in the human-machine relationship, which is more suitable for the rich connotation of the subject.

Ergonomics

(Ergonomics)

Ergonomics is an emerging edge science. It originated in Europe, formed and developed in the United States. Ergonomics in Europe

Called Ergonomics, this name was first proposed by the Polish scholar Jastrebowski, and it consists of two Greek roots. "Ergo" means "output and work", and "nomics" means "laws and rules". Therefore, Ergonomics means "the law of human effort" or "the law of human work", that is, this A discipline is a study of the law of labor and exertion of people reasonably and moderately in the process of production or operation.

Ergonomics is called "Human Engineering" or "Human Factor Engineering" in the United States. Japan calls it "human engineering", or adopts the European name, transliterates it as "Ergonomics", and the Russian transliteration name "" is also used in China. "Ergonomics", "Machine Equipment Utilization" and "Ergonomics". In order to facilitate the development of the discipline, a unified name is necessary. Most people now call it "ergonomics", or "ergonomics" for short.

The exact definition of "ergonomics" is to take the human-machine-environment system as the basic object of research, use physiology, psychology, and other relevant subject knowledge, and reasonably allocate human and machine responsibility according to the conditions and characteristics of human and machine It is a comprehensive subject that creates a comfortable and safe working environment for people and optimizes work efficiency.

Ergonomic Human-Machine System

(Man-Machine systems)

"Human-machine system" is a system composed of people and some machines, devices, tools, appliances, etc. to complete a certain work or production task. Rather, such systems should also include environmental conditions. Therefore, the human-machine system actually refers to an indivisible whole composed of human-machine-environment. The range of human-machine systems is very wide, simple and complicated. For example, if a person writes with a pencil, it is a simple human-machine system; for example, a crew drives a ship, a pilot drives an airplane, and a driver drives a car It is some more complicated human-machine system. In a human-machine system, it includes three components: human, machine, and environment. Each component can be called a sub-system or subsystem. The machine subsystem has a controller and a display (there are many types of displays, including visual, auditory, tactile, etc.). Human, when this sub-system sees (or hears, touches) the display of the display, it must decide how to control and how to operate. If it is necessary to adjust, it can be manipulated by the action of the human body. The entire human-machine system works in a variety of different environments. And environmental conditions affect the work of each sub-system to varying degrees. It can be seen that in the human-machine system, the relationship between man, machine and environment always interacts, cooperates and restricts each other, but man always plays a leading role. Therefore, in order to give full play to the role of humans and machines, so that the entire human-machine system is reliable, safe, efficient, and convenient and comfortable to operate, the characteristics and functions of human and machine must be fully considered when designing the human-machine system To make them coordinate with each other and form an organic whole, to achieve the best results in production and work.

Ergonomic Human-Machine System Design

(Man-Machine systems design)

People need certain machines or devices to complete a certain job or production task, but some machines or devices are suitable for human physiological functions and psychological characteristics, and people feel comfortable and labor-saving, efficient and safe to work. This is not the case for some. Therefore, when designing a machine or device, it is necessary to consider the function of the human body and the psychological characteristics of the human body as much as possible, and strive to meet the various factors of the human body as much as possible when the human touches the machine. The human skeletal structure must be able to adapt to it, the muscle tissue can manipulate it, and the mental system can control it. At the same time, human safety must be ensured when using these machines or devices. If these goals are not met, then all expected outcomes-accidents are likely to occur.

This basic idea of ergonomics must be considered when designing a machine or work space. Generally speaking, the design of human-machine system can be divided into six stages, namely:

(1) Investigation and research;

(2) Preparation of design tasks;

(3) Preparation of implementation plan;

(4) technical design and construction drawing design;

(5) Model making;

(6) Production and identification of man-machine system.

Although these design processes are prioritized, there is a close relationship between the stages and they can also be interspersed with each other.

Ergonomic Deterministic Response

When certain stimuli or signals are available, people often respond to their own experiences and habits. This reaction is called a deterministic reaction. In this reaction process, the central nervous system of the human is relatively simple. As long as the stimulus is perceived, the decision can be made immediately without too much consideration and selection. In general, after the appearance of visual or auditory stimuli, they can respond within 0.14 to 0.18 seconds. Generally, deterministic reactions can be divided into two types, one is a conceptual relationship and the other is a spatial relationship. For example, different colors are often used in the design of various signals and charts. When people see these colors, they can immediately respond because they understand the meaning of the colors. For example, red means danger, stop, and green means safety and traffic. This is all a conceptual relationship. As another example, the words and sentences in books and magazines are arranged from left to right and each line is from top to bottom. This is the arrangement used in horizontal printing. When we read, we must proceed in this order, which belongs to the spatial relationship.

Ergonomic anthropology

(Anthropometry)

Anthropology is a branch of anthropology. It mainly studies the type, characteristics, variation and development of the human body through the overall measurement and local measurement of the human body. Anthropometrics can provide data and information on the strength of human limbs, the limits of motion of muscles and joints, the static and dynamic dimensions of the human body (that is, height and the length of upper and lower limbs, etc.), which are human-machine system equipment The design and spatial layout provide scientific basis. Its significance is:

(1) Propose principles and standards for designing machinery and equipment, workplaces and types of movements, in order to make the best use of time and space;

(2) Coordinate the design of the mechanical equipment with the size, shape, movement and structure of the body, so that humans are labor-saving, comfortable, and have the highest accuracy, the most appropriate speed and the greatest safety;

(3) Make the machinery and equipment receive the maximum benefits.

Ergonomic human response time

The reaction time of the human sensory organs after being stimulated by the outside world is called the human reaction time. The visual simple response time of an average person is 0.2 to 0.25 seconds; the auditory response time is 0.12 to 0.15 seconds. Because human nerve transmission speed generally has a refractory period of about 0.5 seconds, the interval between intermittent operations that requires sensory guidance should generally be greater than 0.5 seconds, and the complex selective response time is generally 1 to 3 seconds, requiring complex judgment and recognition Operation response time is longer.

Ergonomic operation response speed

The reaction speed of the human body is limited. It is related to many factors. As far as the manipulator is concerned, its shape, position, style, size, operation direction, and force will all affect the speed of the manipulator. The speed of human finger tapping is 1.5 ~ 5 times per second, and the maximum can reach 5 ~ 14 times per second. Human hand movement in the horizontal direction of 135 (equivalent to the direction of 1:30 on the horizontal clock surface) or 315 ° (equivalent to the direction of 7:30) has the fastest movement speed and the least number of hand shakes; Slightly slower. The right hand moves forward faster than the right from left to right, and the left to right moves more slowly.

Ergonomic Human Machine System Standard

Human-machine system standards refer to system operation standards and human performance standards. System operation standards have different items and contents according to different man-machine systems. For example, in industrial production systems, there are standards such as product quality, productivity, equipment utilization, and product qualification rate. Human performance standards mainly refer to human physiological and psychological reactions (such as heart rhythm, blood pressure, brain waves), work efficiency, and degree of adaptation. As ergonomics becomes more and more important in human production and life, international standards for ergonomics are becoming more and more important. With the support of the British Standards Institution (BSI) in 1973, the International Ergonomics Society An international seminar on ergonomics was held in the United Kingdom with 13 countries, and many ergonomic standards were put forward. At present, more and more product and production system quality assessments have made ergonomic standards an important content.

Ergonomic human qualities

Human qualities include hereditary innate qualities and acquired qualities formed by the accumulation of practical experience. The response of people to the stimulation of external conditions, that is, the actions they take, will vary according to the quality of each person. That is to say, the most fundamental reason for unsafe behaviors and potentially harmful actions in production sites is that they have a very close relationship with human qualities.

Ergonomic human ecology

In the process of maintaining their survival, human beings gradually adapted to the natural and social environment. This adaptation has formed a certain form of human beings, and the symbiotic relationship between humans and the environment. With this symbiotic relationship as the center, the discipline that studies the structure of human regional society and its changing process is called human ecology. Its research scope also includes health issues that are closely related to human survival, public health, and related topics that are affected by the biological environment, the mobile environment, and the biological individual environment.

Ergonomic unconditional reflection

(Unconditioned reflex)

When external conditions give people a stimulus, people will form two kinds of reflections, one is unconditional reflection and the other is conditional reflection. Unconditional reflection refers to a kind of instinctual physiological function that is born in humans, that is, when the human body is stimulated, a physiological function that can be judged without passing through the brain and instinctively makes a reflection. Food is the most basic thing necessary for people to maintain their lives. Therefore, when people face food stimuli, they directly reflect through physiological functions, and saliva is secreted. This reflection is the most basic automatic control method innate to maintain human life.

Ergonomic psychological reasons

(Mintal cause)

Everything that people do when they work is completely dominated by their state of mind. If the mental state is abnormal, it may cause accidents or disasters. This kind of accident or disaster caused by abnormal psychological state is called psychological cause. There are various psychological reasons for this, such as lack of energy, unhappy mood, excessive fatigue, resistance to the heart, emotional discomfort, and illusion.

Ergonomic external conditions

(Outside condition)

The production activities at the job site are composed of human-machine-environment. If production activities are considered by human action as the main body, all objective conditions presented by objective factors such as machinery, environment and other external factors related to operational actions are collectively referred to as external conditions. Due to different external conditions, the frequency of accidents also varies.

Ergonomics External Information

(Outside information)

People use physiological mechanisms to understand the objective state of things through the "five senses" (sight, hearing, taste, smell, touch), and reach the level of perception. The process is: first understand the external information, and then analyze, judge, and take their own actions. Therefore, most of the causes of accidents are due to insufficient understanding of external information, or the illusion of external information, and external information. Caused by people's unsafe actions.

Ergonomic closed loop man-machine system

(Close man-machine systems)

Closed-loop man-machine system is also a feedback control man-machine system. It has a closed loop structure. Its main characteristics are: the output of the system has a direct impact on the control function, that is, the results of the system's past actions come back to control future actions. For example, in a certain system, if a certain input voltage needs to be added to obtain the required target value, if the input voltage is too large, this system will work by adjusting to reduce the input voltage. Conversely, if the input voltage is too small, this system functions to increase the input voltage. The control method with this structure is feedback control. This kind of control is called artificial closed-loop man-machine system if it is observed and controlled by humans. If an automatic control device is used to replace the work of a person, and the person only plays a supervisory role, the system is called an automatic closed-loop man-machine system.

Ergonomic seat geometry parameters

The geometric parameters of the seat mainly include seat height, seat surface depth, seat back, seat surface width and the like. The seat width is generally only 50cm to meet the requirements. The seat height is very important for the ergonomics of the worker. Generally, the height of the fibula head of the human body (about 1/4 of the total human height) or slightly lower than the height of the calf is about 1cm. According to the height of the human body in China, the seat height is generally 43 ~ 45cm, and the seat surface depth is generally about 45cm. In addition, the seat surface must be smooth and flat, and the seat surface can be inclined slightly backward by about 6 °. Generally, an elastic seat must be added. There are two parts of the shoulder and waist. The height of the shoulder should reach the lower angle of the scapula. The height of the waist should be suitable for the height of the spine and the waist. The two backs are connected together. The height is generally about 50cm. The angle between the seat and the back is average. It is 100 ~ 110 degrees, so that when a person sits up, the backrest and seat surface match the curve formed by the back, hips, and thighs of the human body, making people feel comfortable.

Ergonomic controller layout area

The controller layout area refers to the most flexible, most responsive, and most suitable space range and routine orientation when the manipulator is operated by human hands (or feet). The layout area of the manual controller is: when the elbow is not in motion, the elbow is the center of the spherical area with a radius of 35.6cm, and the shoulder height is the best position. When the elbow is in motion, the radius of the spherical area can be expanded to 40.6. cm; when the body is not moving, with the shoulder as the center and a spherical area with a radius of 61cm; when the body is allowed to move, the above radius can be enlarged to 76cm. The foot controller layout area is that when a person is sitting and operating, the foot pedal must not deviate from the center line of the human body by 7.5 to 12.5 cm, and the height of the foot pedal must not exceed the height of the seat surface; if standing, the height of the foot pedal must not exceed The ground is 75cm, preferably 20cm above the ground or slightly lower. In addition to considering the movement organs (hands, feet, etc.) of the controller, it is necessary to pay attention to the visual requirements.

Ergonomic horizontal operation area

All operations on the operating platform belong to the scope of horizontal operations. This category has the most jobs. Horizontal operation is divided into normal operation area and maximum operation area. The normal operating area (mormal area) refers to the range of movement that the upper limb can easily reach in the horizontal direction within the natural position range of the operator. The maximum operating area (maxinum area) refers to the maximum range of movement of the entire upper limb on the horizontal plane.

Ergonomic Discomfort Index

The discomfort index refers to a person's uncomfortable feeling due to the change in temperature and humidity. The discomfort index can be calculated using the following formula:

Dry bulb temperature [] + wet bulb temperature [] × 0.72 + 40.6

It is generally believed that when the discomfort index reaches 70 or more, some people feel slightly uncomfortable; when it reaches 80 or more, all people start to feel uncomfortable.

Ergonomic unsafe conditions

(Unsafe condition)

The potential danger of all external conditions during the operation of the operator is called unsafe conditions. For example, unfavorable environmental conditions (high temperature, humidity, harmful gases, dust and obvious noise); or defective equipment, devices, machinery; or defective operating appliances, auxiliary tools, protective equipment, etc. Most of these have the potential to cause accidents.

Ergonomic work space

Working space refers to the total space required for human activities when operating the machine, plus the space required for machines, equipment, and tools. Modern operations have high requirements on the design of the working space, which requires a reasonable relationship between all machines, equipment, tools and people's operating activities. The working space is economical, reasonable, and convenient and comfortable for the operator.

Ergonomics Environmental Factors

Operating environmental factors refer to the different environmental conditions that people face when working in different situations, different types of work, and different environments. Such as the high temperature of smelting operations, the high temperature of textile workshops, the radiation of the atomic energy industry, the high pressure of deep-water operations, and the lack of oxygen at high altitude. These unfavorable environmental factors all directly or indirectly affect people's operations. On the one hand, they reduce work efficiency and on the other, they affect the operation of the entire system and endanger human safety. In general, the environmental factors that affect people's operations include: physical and chemical properties of environmental factors, including chemical gases, steam dust, fume, and droplets. Environmental factors of physical properties generally include light, radiation, vibration, humidity, noise, and water pressure.

Ergonomic control-display ratio

Control-display ratio is an important human-machine factor that needs to be considered when designing the manipulator. It refers to the proportional relationship between the operation amount of the manipulator and the display amount of the display (pointer). Its expression is

B = C / D

In the formula, B is the control-display ratio: C is the amount of movement (or rotation) of the controller; D is the amount of display (indicator).

When the system is operating, the joystick moves 4cm, and the target on the display screen moves 1cm, then the control-display ratio is 4. For another example, when the knob switch arm rotates 1 unit value, the indicator pointer moves 5 unit values, and the control-display ratio is 0.2. Designing a control-display ratio is important for quantitative adjustment or continuous control. Generally speaking, a control controller with a small display-ratio is suitable for coarse or fast adjustment; a control controller with a large display-ratio is suitable For fine tuning.

Ergonomic hue contrast and reconciliation

The contrast of hue refers to the differences in hue, the depth of lightness, the level of purity, the difference in heat and cold, the size and location of the area. Colors with large differences in purity, warmth, and lightness are contrasted, and vice versa. Contrast is to expand the differences and oppositions of colors in all aspects, while harmony is just the opposite. It is to reduce the differences in colors, neutralize the oppositions, and increase commonality. The colors of various harmony are: The colors between adjacent colors are blended colors), purity blended (multiple colors with similar purity on the color ring), and warm and cold blended (colors with similar degrees of warmth and coldness). For example, when two or more colors are not reconciled, a few colors with gradients are inserted between them to make them reconcile.

Ergonomic actions

(Actus)

The meaning of the action is the real state of a physical phenomenon of a certain action displayed in the course of time. It is derived from Latin and refers to the action function of a behavior, to control the movement of an object, or to make an object move. When this action is incorrect, it is the real cause of the accident; if reasonable action is taken or dangerous actions are eliminated, this action becomes the core of preventing accidents in production.

Ergonomic movement stability

(Stability of conduct)

The work movement is the continuous work posture in a very short time. The continuous change of posture is the result of the physiological functions exerted by the muscle contraction in order to adapt to the external conditions, as a result of instructions from the brain. It is necessary to maintain the stability of the working posture at this moment. If this stability is disrupted and a disorder in the normal posture occurs, it will be the cause of the accident. The stability of movement is the continuity of the stability of this instantaneous working posture. To ensure the stability of this control, repeated training is required.

Ergonomic adaptability

(Aptitude of conduct)

A person's character is formed through heredity, or acquired experience acquired with the environment in which he lives and the influence of other factors. Therefore, people's stimuli to the same external things do not necessarily show the same reaction, or even completely show the opposite reaction. Like the directional nature of human character, workers in enterprises also exist in operation. This directionality greatly affects the occurrence of the accident. The so-called adaptability of action is the adaptability produced according to this directional characteristic of people. Generally speaking, whether a person has adaptability to a certain task is judged by evaluating various functions of the person.

Ergonomic action analysis

(Motion study)

In order to make the operator's work movements in the production process reasonable and effective, that is, in order to obtain the maximum effect at the least cost, it is necessary to analyze and study the movements one by one. This is called movement analysis or movement research. Because most accidents are caused by the operator's unsafe movements, removing unnecessary and dangerous movements in work movements or finding ways to improve the movements through movement analysis is an effective way to prevent accidents. .

Ergonomic action management

(Motion management)

At the work site, there are often many unsafe factors in the movements of workers. Therefore, it is necessary to formulate a reasonable standard for each operation, no matter from the perspective of improving work efficiency or safety. At the same time, workers are educated and trained in accordance with the prescribed standard actions, and on this basis, the workers who meet the standards are required to supervise the operations of other workers in accordance with the prescribed operating standards, so that during the operation, workers Can operate correctly. The work performed for this purpose is called action management.

Ergonomic action track

(Motion locus)

This is a method used when studying work movements. For example, in order to understand the movements of the hands and feet, a small light bulb can be installed on the hands and feet, and then the trajectories of the hands and feet can be photographed on a photographic film. In this way, according to the movement trajectory, it is possible to discover the difference between the movements of skilled and unskilled workers, and also to find the defects in the actions that are prone to accidents. Generally speaking, the movement trajectory of unskilled workers is unstable. Therefore, this unstable movement is prone to accidents.

Ergonomic color adjustment

(Color conditioning)

The technology that uses the nature, function, and science of color to create a comfortable and safe working environment for workers is called color adjustment. The direct effect of applying this technology at the production site is that the operating environment is suitable, the operator can easily distinguish surrounding machines, workpieces, etc., the eyes are not tired, the spirit is good, the concentration is concentrated, and the light can be effectively used; the indirect effect is orderly, accident Reduced, the rejection rate decreased, and work efficiency improved.

Ergonomic working temperature

(Operative temperature)

It is a temperature display developed according to Newton's cooling law. It indicates the indoor temperature, airflow, wall temperature (the surrounding

Radiation temperature), a measure of the heat exchange relationship with the surface of the human body.

Ergonomic continuous action

(Continors movement)

To the changing external conditions, the operator must respond to the continuous action in a timely manner, which is called continuous action. For example, the operation of a car driver while driving a car and the cutting operation of a machine tool fall into this category.

Ergonomic heat radiation

(Heat radiation)

A form of direct dissipating heat energy from a high-temperature heat source. Heat radiation has nothing to do with the medium surrounding the heat source. In addition, the radiant heat emitted from high-temperature heat sources follows the Stefan-Boltzman radiation law, that is, the temperature of heat radiation is proportional to the fourth power of the absolute temperature of the radiation source.

35 Ergonomics 35 Program Control

(Sequence control)

When there are several automatic control device systems at the same time, in order to achieve the same purpose, the operating sequence of these device systems must be determined. Otherwise, the operation sequence must not be operated, which is program control. Program control is also very important to ensure the safety of a series of mechanical devices in the occasion of automatic control operation.

Ergonomic Operation Research

(Work study)

Investigation and research on the rationality of operation methods is called operation research. Reasonable operation methods should avoid product defects and waste of materials in production, and can stabilize production in this standard. Production accidents are mainly due to the unstable operation methods of workers and freewheeling. operating. Therefore, operational research is the most powerful means to make operations safer.

Ergonomic operation speed

(Work tempo)

The operating speed refers to the speed of the operation during the operation. When the operation is performed, there is a problem of the speed of cooperation between a certain action and the whole action. If the operation speed is disturbed by some external conditions, the workers will focus on meeting the external conditions. Dangerous states and conditions can not concentrate, resulting in disordered movements, conflicts, and the possibility of accidents.

Ergonomic display

Various devices for displaying information in a human-machine system are collectively referred to as displays. It includes meters, signal lights, signal boards, signal boards, various signs, symbols, warning bells, signal sounds, alarm sounds, radar screens, TV screens, and other devices that display information. In order to operate the machine and monitor the operating conditions in the human-machine system, it is necessary to transmit information, that is, the "human" constantly adjusts the "human" manipulation activity according to the "machine" activity. From a machine perspective, the display is output, and from a machine operator's perspective, the display is input. The display is generally divided into a visual display, an audible display, a tactile display, a taste display and an olfactory display. The main ones are visual and auditory displays.

Ergonomic vision

Vision is the ability of the eye to recognize the details of an object, and is used as a criterion for evaluating the eyes to distinguish small objects (clarity). Its quantity is the reciprocal of the angle of view (critical perspective) at which the eye can distinguish the last two points of the viewed object. It increases with illumination, background brightness, and the contrast (contrast) between the object and the background. When the background brightness increases from zero to about 600 cd / m, vision increases rapidly; when the background brightness continues to increase from 600 cd / m, the effect on vision is not significant. When designing the product size and the accuracy of the instrument dial, vision is a factor that must be considered. In order to improve vision, the background brightness and illuminance must be increased, or the contrast of components and background brightness must be increased.

Ergonomic Perspective

The angle of view is the angle of intersection of the light emitted from two points in the viewed object into the eyeball. It is related to the observation distance and the distance between two points on the object being viewed.

= 2arctg (D / 2L)

Where is the angle of view (degrees); D is the distance between two points on the object being viewed; L is the distance from the eye to the object being viewed.

In design, the perspective is the basis for determining the size of the design object.

Ergonomics micro and macro vision

The use of microscopes and telescopes has expanded people's vision. The resolving power of a normal human eye is 0.075mm (that is, when the viewing distance is 25m, the minimum distance between two points that an eye can distinguish between objects is 0.075mm). When using a microscope, the resolving power can be increased by tens of millions. Modern electric microscopes have been able to magnify tiny objects about 2.5 million times. We call the tiny world shown in this way the micro world, and the scope of the micro world that human eyes can see through a microscope is called the micro visual field. With a telescope, you can see a huge world for a tiny world. As early as 1948, the United States installed a 5.08m reflecting telescope on Mount Panama, which can be used to clearly see the cosmic space as far away as 18.921 × 10m (2 billion light years) from the earth. This is giant vision. The huge world we see in this way is called the macro world, and the scope of the macro world that human eyes can see through a telescope is called the macro vision. Now, with the aid of instruments, human vision is constantly expanding in both micro and macro directions.

Ergonomic visual display

The visual display displays information that is transmitted to the brain through the optic nerve of the human eye. The process of vision formation is that when external objects stimulate photoreceptor cells on the retina, the nerve impulses generated by these cells are transmitted along the optic nerve to the visual center of the cerebral cortex, and vision is produced. Human vision is related to the intensity, color, and surrounding environment of light. Therefore, the design of visual displays requires clear, legible and accurate figures. Studies have shown that the shape of the display dial plays an important role in the accuracy of the reading. The misreading rate of the window-type direct reading display is only 0.5%; the circular or circular type is 10.9%, the semi-circular type is increased to 16.6%; and the linear vertical type is as high as 35.5%. The visual display is divided into the following types according to the purpose, that is, the display instrument for the purpose of quantity reading, quality reading and inspection reading. Therefore, it is required to meet the purpose of use as much as possible when designing. For quality-reading instruments, the simpler and clearer the better.

Ergonomic auditory display

The external sound wave passes through the human ear canal to the eardrum, causing the eardrum to vibrate, stimulating the auditory receptors of the inner ear, and causing the auditory receptors to generate nerve impulses. These nerve impulses are transmitted along the hearing-related nerves to the auditory center of the cerebral cortex to form people Hearing. The display signal of the auditory display is the mechanism through which the operator responds to control the machinery and equipment through the human auditory organ. The system designer should make a decision on whether to use the auditory display based on the role of information, characteristics and operating conditions. For example, in many job sites, the visual information load is often large. If the auditory channel can be used to share some tasks, the information load of the visual channel can be reduced, and the purposes of safe production and improved work efficiency can be achieved.

The following principles should be followed when designing an auditory display.

(1) Consistency principle: The signal itself can be used to explain the operation of the equipment, and the signal can be logically linked with the familiar phenomenon;

(2) Discrimination principle: the actual situation on the job site must be considered, which is obviously different from other sounds;

(3) Conciseness principle: The signal should be as simple and clear as possible, and the signal should not be excessive or complicated;

(4) Invariance principle: The same auditory signal is required, and the same information must always be expressed.

Ergonomic tactile display

In addition to visual and auditory displays, human touch can also be used as a channel for information transmission. Tactile displays are called tactile displays. Tactile displays are commonly used with electrical stimuli, mechanical vibration stimuli, and jet stimuli. The electrical stimulation signal is relatively strong, which is more advantageous as a warning signal, but its disadvantage is that it is easy for people to adapt, so it is not suitable for long-term use. The adaptability to vibration stimulation is small, suitable for long-term use. The strength of the jet stimulus is low, and people's ability to distinguish it is poor, so it is not suitable for the transmission of complex information.

Ergonomic experiment

It is one of the commonly used methods in ergonomic research. If the actual measurement method cannot be performed due to the limitation of the conditions, an experimental method can be adopted, usually in a laboratory, but sometimes it can also be performed in other environments. If in order to obtain a person's pressing pressure on a certain type of button switch during operation, and to obtain the feel and comfort, the data required by the human body, generally, a short test can be performed at the job site or in the laboratory. If you want to get the effect of color environment on people s psychology, physiology and work efficiency, it is usually impossible to solve short-term experiments in the laboratory. At this time, it is necessary to continue for a period of time to respond to the different reactions of workers in various color environments. Observation of time can get more realistic results. The experimental data can be used as a scientific basis for designing such machines, components and working environments.

Ergonomic muscle fatigue test

In order to study the human body's response to various physical labor and other loads, the German scholar A. Mosso conducted a muscle fatigue test on human labor fatigue. The test method is: when a person is performing work, a micro current is passed through the body, and it is found that the intensity of the current changes with the degree of fatigue of the body. In this way, the degree of fatigue of the human body can be measured using electrical signals. This kind of experiment laid the foundation for the later research on labor physiology.

Ergonomic shovel operation test

In 1898, the American scholar F.W. Tyrol carried out detailed observation and analysis of the workers' operating actions based on his decades of work experience to determine a reasonable working method, select appropriate tools, specify standard working hours, Improve labor efficiency. He used four shovel with the same shape and different shovel capacity (four shovel weights of 5kg, 10kg, 17kg and 30kg each time) to shovel the same pile of coal. Although the 17kg and 30kg shovel has a large amount of shovel each time, the test results show that the 10kg shovel is the most efficient for shovel coal. He did many experiments and finally found the best design of the shovel, and found the most appropriate weight of each shovel when handling loose granular materials such as coal chips, iron chips, sand and iron ore. As a result, labor productivity is greatly improved. This is the well-known shovel operation test in the process of ergonomics.

Ergonomic Bricklaying Test

In 1911, American scholar F.B. Kils conducted a test on the brick-laying work of American construction company workers. He used a fast camera to shoot the workers' brick-laying movements, and then analyzed and studied the movement process. Which movements are necessary and which are redundant. Remove unnecessary invalid movements and improve the efficiency of effective movements. This is the famous time and movement research. As a result, workers' brick-laying speed increased from 120 to 350 at the time. With the development of mechanized production, from the time to study the distribution of actions and time, and then to the utilization of human and machinery and equipment, thereby improving production efficiency, this is the basis of modern ergonomics.

Ergonomic analysis

The analysis method is based on the actual measurement method and experimental method. If you want to analyze the movement of a person when operating a machine, you must first carry out actual measurements, that is, record each continuous movement completed by the person with an instrument or photography one by one, and then analyze and study to eliminate the invalidity. Action to correct bad posture, so as to effectively reduce human labor intensity and improve work efficiency. Especially when an action has to be repeated thousands of times in an operation shift, using this method, even if only one action is removed or improved, it will play an important role in improving production efficiency. In the analysis method, two variables of independent variable and dependent variable are usually studied. The independent variables are measured data (factors), such as illuminance, environmental conditions, and gravity. The dependent variable is a factor that changes with the independent variable. The relationship between these two variables is studied in order to find out the rules and provide a reliable basis for the design of machines and devices.

Research on Ergonomic Operational Accidents

(Working motion strdy)

The causes of production accidents can be divided into physical and human causes. The physical cause refers to the accident caused by the failure of the design or manufacturing of the equipment or tool, and the human cause refers to the accident caused by the unsafe behavior during the operation. Operation action accidents mainly refer to accidents caused by workers 'unsafe behaviors at the workplace. These unsafe behaviors include the operator's own unsafe behavior and the collaborator's (cooperator)' s unsafe behavior. And unsafe behavior often happens during the operation of machinery or tools. There are the following types of accidents:

(1) Accidents due to unsafe behavior during human handling;

(2) Accidents in which operating tools and manual mechanical processes violate operating regulations;

(3) Accidents due to unsafe behavior during the operation of the lifting and handling machinery;

(4) Accidents caused by flying objects or falling objects due to incomplete protective equipment or inadequate wearing requirements during operation;

(5) Accidents caused by slipping or tripping during operation.

Preventing and investigating the above accidents is an important part of preventing accidents at work. The purpose of the study was to develop norms and procedures that prohibit arbitrary operations and minimize unsafe behavior.