Analysis of Human-Machine System

The human-machine relationship has evolved from people operating tools, people adapting to machines, and machines fitting people to modern human-machine coordination. There is a certain limit to a person's ability to adapt to machines. A further solution to the human-machine relationship is to improve machines to make them suitable for human operation.

Lean production indicates that among common wastes, the waste of movements is also one of them.

A human-machine system design

Human-machine system design is the design of the entire system from the perspective of systems engineering. This design process has three main features: The first is the separation of functional and physical issues. Analyzing functional issues is an independent and clear stage at the beginning of the design activity, and this stage mainly involves building the model required by the system. The second feature is to treat people as an organic component of an overall system. The principles of engineering design cannot be directly applied to machines or equipment without considering the factors of the people who use and keep these machines. When allocating and determining the functions of machines, human capabilities should be fully taken into account. The third feature is to define and classify the design in an organized manner to ensure that it provides designers with a systematic framework, thereby reducing details that might be overlooked.

The object of our research is the overall state and process of the human-machine-environment system. It is consistent with the viewpoint of systems engineering, which takes systems as the object and focuses on the overall state and process. Therefore, the human-machine system should be analyzed from the perspective of systems engineering.

(1) Contents and Principles of Human-Machine System Evaluation:

1. The evaluation content: The evaluation must conduct a comprehensive assessment of the overall characteristics and functions of the three major elements of human, machine and environment in the human-machine system, including:

Determine the applicable evaluation methods, evaluation objectives and evaluation standards.

(2) Based on the given evaluation procedures and methods, conduct an objective, qualitative or quantitative assessment of the system. By integrating the overall, technical, human-friendliness, safety, economic and other goals as well as empirical data, identify the optimal solution and the best working conditions for the system.

(3) When the technical and economic conditions are difficult or impossible to achieve the expected goal, a feasibility study should be conducted on the planning or design scheme, and repeated evaluations should be made to meet the purpose of optimization.

The purpose of evaluating human-machine system design is to adjust the system based on the evaluation results, carry forward its strengths, improve its weak links, eliminate adverse factors or potential crises, and achieve the optimization of the system.

2 Evaluation Principles:

The human-machine system is a subsystem of the product system. Therefore, its evaluation should start from the entire system and follow the principles of combining local interests with overall interests, current interests with long-term interests, internal conditions with external conditions, and qualitative analysis with quantitative analysis to comprehensively assess the quality of the design plan. The following principles should be noted in the evaluation methods:

(1) Objectivity of the evaluation method: When evaluating, the influence of the evaluator's subjective factors should be prevented. Therefore, reliable data should be provided, and the range of data values should not be too large; otherwise, it will leave the evaluator at a loss. At the same time, the survey results should be checked.

(2) Universality of the evaluation method: The evaluation method is applicable to evaluating various systems at the same level.

(3) Comprehensiveness of the evaluation method: It should be able to reflect the important functions and factors of the evaluated object in all aspects, so as to truly reflect the actual situation of the evaluated object.

(II) Establishment of Evaluation Objectives

1. Evaluation objective

The first step in evaluation is to design the evaluation objective, from which the evaluation elements can be derived and a plan can be designed based on the evaluation results. There are usually multiple goals to set, which can be summarized into the following three main aspects.

Technical evaluation objective.

(2) Economic evaluation objectives

(3) Design evaluation objectives

2 The prerequisite conditions for establishing goals

When setting goals, the following conditions should be met as much as possible:

1) The objective should include as many requirements and general conditions as possible that are of significant importance to the judgment, so as not to overlook important bases during the evaluation.

2) When conducting evaluations, the various objectives on which they are based must be independent of each other, that is, measures that affect the value of one objective do not affect the value of other objectives.

The characteristics of each objective in the system to be evaluated should be simple and clear, expressed quantitatively as much as possible, or at least qualitatively expressed with clear questions

(3) Definition of human-machine operation program diagrams

Human-machine operation program diagram: It is a kind of chart recorded on the same time coordinate and reflecting the cooperation relationship between the operator and the machine. It can clearly show the temporal coordination relationship between the working cycle of humans and that of machines. Therefore, through the analysis of the human-machine operation program diagram, a new method can be adopted to reduce the idle time of humans and machines and improve their efficiency.

(4) Work Rationalization Checklist

1. A checklist concerning people

• Whether the physical condition is suitable for this assignment;

Whether the ability is sufficient and whether an operation certificate is held;

• Is there any knowledge of work research?

Is there a correct operation instruction manual?

Whether the operator themselves can make good preparations for the operation and the selection of tools;

Are there any tools that can be utilized?

• Should the working conditions be changed?

• Are there any difficult tasks?

• Whether the work is stressful for a long time;

Has consideration been given to preventing hazards?

Whether the work service is smooth and convenient.

2 A checklist related to the machine

Whether the machine is in line with its intended use;

Could it be more simplified? Are there any dedicated machines?

• Who maintains the machine;

Can the machine turnover rate be increased?

Can one person operate multiple machines?

Whether the operation rate of the machine is good;

Has preventive maintenance been done well and who is responsible for it?

Is there a repair shop?

Whether the operation of the handwheel and buttons is easy;

Whether the positions of the switch and handwheel are within the appropriate operating range;

• The number of hands in the control part;

Whether the heat and cold protection of the operation part is sufficient;

Whether inexperienced novices can operate it;

Whether inappropriate working methods can be avoided in the organization;

Are there any dangerous parts and any hazard prevention devices?

. Whether the start switch of the machine is within the operating range.

The steps for drawing a human-machine diagram

The steps for drawing a human-machine diagram

First, it is necessary to clarify the operator and the content of the process operation;

The sequence of these tasks and their simultaneous relationships must be clearly defined.

• Determine the time required for each operation;

Identify where the operation of the operator and the machine starts or finishes simultaneously, and consider their sequence and simultaneality to draw a human-machine diagram based on the current situation.

Monitor the time the operator spends on the machine, consider the sequence and simultaneous relationship of each operation, and try to change the operation sequence to reduce their waiting time.

Based on the human-machine diagram drawn by changing the operation sequence, further discuss the improvement countermeasures in detail and estimate the improvement effect.

2. Things to understand when drawing a human-machine diagram:

During the operation in process 1, the job contents of each operator and the machine, as well as their sequential relationship;

The operational association status between the operator and the machine;

Master the "waiting time" of operators and machines, as well as the occupancy percentage.

Therefore, the following issues can be explored by using human-machine diagrams

• There is a significant waiting state among the operators or machines, or the operation rate is low;

Although the time for each assignment is known, the exact time required for a process cannot be determined.

How does the arrangement of personnel or the number of machines affect the process time and what is the operation rate?

3. Human-machine system analysis diagram

All the data in the following table were collected from the processing of YZl4JG by two CNC vertical lathes and one CNC drill at the construction machinery manufacturing plant. 2-1 Bearing housing, analyze and organize the collected data, and draw the following table, as shown in Figure 1, human-machine system analysis (before improvement).

From Table 1, we can see from one analysis period that the following several problems exist:

The waiting time for driving is too long, averaging more than 5 minutes.

2. The time for program adjustment can be shortened.

The idle time of the second CNC lathe is 25 minutes, and that of the CNC drill is 40 minutes. The rest time for the workers is 25 minutes for the second CNC lathe and 40 minutes for the third one, which is obviously too long. This undoubtedly leads to a waste of human resources. Besides, the processing time of the machines is quite long, so the workers could have taken care of one or two more machines.

Based on the above analysis, we have proposed the following improvement measures:

When the weight of the bearing housing is between 50 and 100 kilograms, flexible lifting equipment can be considered to avoid competing with large equipment for the crane.

2. Rough turning uses CNC equipment to make the process dimensions suitable for programming operations and reduce the time for program adjustment.

3. The second and third devices should be operated by one person to avoid waste of human resources.