What is a human-computer interface?
The human-machine interface (HMI) refers to the area where humans and machines interact or influence each other in terms of information exchange and functionality. This interaction encompasses both physical and software contact between humans and machines, including direct contact at points, lines, and surfaces, as well as the operational space for long-distance information transmission and control. The HMI is a central link in human-machine systems, primarily studied and addressed by the branch of safety engineering, specifically safety ergonomics. It involves safety equipment engineering, safety management engineering, and safety systems engineering in researching specific solutions and measures. HMI facilitates the conversion between the internal form of information and a human-readable format. Human-machine interfaces exist in all areas involving human-machine information exchange. Widely used in industry and commerce, human-machine interfaces (HMIs) can be simply divided into two types: "input" and "output." Input refers to the operation of machinery or equipment by humans, such as handles, switches, doors, issuing instructions (commands), or maintenance. Output refers to the notifications issued by machinery or equipment, such as faults, warnings, and operating instructions. A good HMI helps users operate machinery more easily, correctly, and quickly, and also enables machinery to achieve maximum efficiency and extend its service life. However, the HMI referred to in the market is often narrowly defined as a user-friendly software interface.
Human-computer interface design principles
1. User-centered basic design principles
During the system design process, designers must grasp the characteristics of users and discover their needs. Throughout the system development process, they should continuously solicit user feedback and consult with them. System design decisions must be combined with the users' work and application environment, and their requirements for the system must be understood. The best approach is to involve real users in the development process; this allows developers to accurately understand user needs and goals, leading to a more successful system.
2. Order Principle
That is, the main interface and its secondary interfaces for monitoring and management and human-computer interaction are designed according to the order of event processing, the order of access and viewing (such as from whole to single item, from large to small, from top to bottom, etc.) and the control process flow.
3. Functional Principle
According to the specific functional requirements of the application environment and occasion, the requirements of parallel processing of the same interface for different subsystem control types and the requirements of simultaneous interaction of multiple dialogs, the human-computer interaction interface is designed with multi-level menus with different functions, layered prompts and windows with multiple dialog bars, so that users can easily distinguish and master the usage rules and characteristics of the interaction interface, thereby improving its friendliness and ease of operation.
4. Principle of Consistency
This includes consistency in color, operating areas, and text. On the one hand, the interface colors, shapes, and fonts should conform to national, international, or industry standards. On the other hand, the interface colors, shapes, and fonts should be self-contained, and the colors should remain consistent across different devices and even those with the same design. Consistency in the interface's detailed aesthetic design makes the interface comfortable for operators, thus preventing distractions. For new operators or those handling emergencies, consistency can also reduce operational errors.
5. Frequency principle
This involves designing the hierarchical order of the human-computer interface and the display position of the dialog window menu according to the frequency of dialogue interaction with the managed objects, thereby increasing the frequency of monitoring and access dialogue.
6. Principle of Importance
In other words, the location and prominence of the main and secondary menus and dialog windows of the human-machine interface are designed according to the importance and overall level of the managed objects in the control system. This helps managers to grasp the priorities of the control system, implement control decisions in the correct order, and achieve optimal scheduling and management.
7. Object-oriented principles
This means designing a user-friendly human-machine interface that is appropriate for the operator's identity and job nature. Based on their work needs, pop-up windows should be used to display prompts, guidance, and help information, thereby improving user interaction and efficiency.
Human-machine interfaces (HMIs), whether for field controllers or higher-level monitoring and management, are closely interconnected. They monitor and manage the same field devices, thus many field device parameters are shared and exchanged between them. Standardized HMI design should be the future direction, as it truly embodies the fundamental principles of ease of use, simplicity, and practicality, fully expressing a human-centered design philosophy. Various industrial control configuration software and programming tools provide powerful support for creating sophisticated HMIs, and their advantages become increasingly apparent with larger and more complex systems.
Human-computer interface design process
1. Creating an external model of system functions: The design model primarily considers the software's data structure, overall structure, and procedural description. Interface design is generally secondary. Only by understanding the user's situation (including age, gender, psychological state, education level, personality, and ethnic background) can an effective user interface be designed. The user model is designed based on the end-user's hypothetical vision of the future system (referred to as the system hypothetical), ultimately ensuring it matches the system image (external characteristics of the system) obtained after system implementation. Only then can users be satisfied with the system and use it effectively. When building the user model, the information provided by the system hypothetical must be fully considered; the system image must accurately reflect the system's syntax and semantic information. In short, only by understanding the user and the task can a good human-computer interface be designed.
2. Determine the tasks that humans and computers should perform respectively to complete the functions of this system.
There are two approaches to task analysis. One is to start from reality, analyzing existing application systems that are in a manual or semi-manual state and mapping them to a set of similar tasks to be performed on the human-computer interface; the other is to study the system's requirements specification and derive a set of user tasks that are consistent with the user model and system assumptions.
Techniques such as incremental refinement and object-oriented analysis are also applicable to task analysis. Incremental refinement can continuously divide a task into subtasks until the requirements of each task are very clear; while object-oriented analysis can identify all objective objects related to the application and the actions associated with those objects.
3. Consider typical problems in interface design
When designing any user interface, four aspects must generally be considered: system response time, user help mechanisms, error message handling, and command methods. Excessive system response time is the most frequent complaint from users in interactive systems. Besides the absolute length of the response time, users are also very concerned about the differences in response time between different commands; if the difference is too large, users will find it unacceptable. User help mechanisms should be integrated to avoid a layered system where users have to browse through a lot of irrelevant information to find a specific guide. Error and warning messages must use clear and accurate terminology, and should also provide suggestions for error recovery whenever possible. Furthermore, supplementing error messages with auditory (ringtone) and visual (dedicated color) stimuli will enhance the effect. The best command methods are a combination of menus and keyboard commands for users to choose from.
4. Constructing an interface prototype using CASE tools and actually implementing the design model: Once the software model is determined, a software prototype can be constructed. At this stage, only the user interface portion is present. This prototype is submitted to users for review, modified based on feedback, and then submitted to users for review again until it aligns with the user model and system assumptions. Generally, ready-made modules or objects provided by User Interface Toolkits or User Interface Development Systems can be used to create various basic interface components.
5. The human factors to be considered in human-computer interface analysis and design mainly include the following:
1) Human-computer compatibility: Users are people, and computer systems are tools for people to complete tasks. The human-computer system composed of computers and people should be well matched in working; if there is a conflict, the computer should adapt to the human, rather than the human adapting to the computer.
2) Inherent Human Skills: Humans, as computer users, possess many inherent skills. Analyzing and synthesizing these abilities helps to estimate or judge what a user is capable of handling, the complexity of the human-computer interface, how much knowledge and assistance a user can gain from the interface, and the time spent.
3) Inherent human weaknesses: Humans have inherent weaknesses such as forgetfulness, error-proneness, poor concentration, and emotional instability. A well-designed human-computer interface should minimize the amount of memory required for users and strive to avoid potential errors.
4) User's knowledge, experience, and education level: The education level of a computer user determines their knowledge and experience with computer systems;
5) Users' expectations and attitudes toward the system.
Human-Computer Interface Design Case Analysis
I. Home Appliance (Refrigerator) Haier BCD-231WDBB
Location: Refrigerators are one of the most common household appliances in kitchens. They are also found in public spaces such as restaurants and hotels.
Function: A refrigerator keeps food or other items cold and has the functions of storage and freezing.
Human-computer interface analysis:
1. Handle:
① Position: The handle design conforms to the height structure of the general population. It is generally designed according to the actual height of the refrigerator. For example, the total height of this refrigerator is 1722mm. It has a three-door design, and the handles are about 550mm, 950mm and 1300mm respectively.
② Shape: This refrigerator handle features a concealed design, giving the machine a unified and aesthetically pleasing appearance. The handle is shaped like a rectangular groove, suitable for most family members with varying heights. ③ Function: This handle design utilizes hand movements, allowing users to control the refrigerator door by gripping or pulling. It has a stylish appearance, is easy to open, does not accumulate dust, and is easy to clean.
2. Storage space:
① Location: This refrigerator has a three-door design, separating two different storage spaces: a refrigerator compartment and a freezer compartment. The upper and lower doors are proportionally distributed, and the middle door offers a variable temperature range of 5°C to 18°C.
② Shape: All three storage compartments are rectangular, divided by a rectangular partition in the middle, creating a tiered design suitable for storing different types of food. The freezer compartment features a drawer design, greatly expanding the freezer space. The drawers are decorated with bright silver faux-metal trim, giving them a high-quality feel and ensuring durability.
③ Function: The refrigerator compartment is mainly used to store fresh or cooked food. Seafood and meat are placed in the refrigerator compartment for 24 hours to detoxify at low temperatures before being stored in the freezer compartment. The freezer compartment is generally used to store seafood, meat, and other foods that need to be stored for a longer period of time without being used.
3. Display section and buttons:
① Location: The display and buttons are generally within eye and hand reach. In this refrigerator, they are located approximately 1650mm above the center of the panel.
② Shape: The display buttons on this refrigerator are vertically rectangular, consistent with the overall design and creating a cohesive look. They are divided into four areas from top to bottom, separated by solid black lines: temperature zone selection, temperature adjustment, function selection, and setting. The top three areas are LED-lit LCD displays, and the setting buttons are circular, touch-sensitive, and easy to operate.
③ Functions: This refrigerator uses computer-controlled temperature for its display buttons. The refrigerator and freezer temperatures can be adjusted separately via the setting buttons, and it also has a memory alarm function. The temperature zone selection display shows three white square lights arranged vertically, the temperature adjustment display shows the white Celsius temperature, and the function selection displays three functions: Smart, Holiday, and Energy Saving, with graphics and text.
II. Everyday Items (MP3) iPod Classic
Location: Suitable for home and outdoor music playback devices, applicable to a wide range of people and widely used.
Function: Music playback.
Human-computer interface analysis:
① Appearance and Shape: The design is simple, with only a single circular button and a power button on the top. The four edges of the machine are rounded, giving it a more rounded feel and maintaining consistency with the central circular button. The power button on the top is also oval. The overall design emphasizes a rounded aesthetic, with attention to detail evident throughout.
② Material: The front is made of frosted aluminum, the middle button is made of plastic, and the back is made of polished aluminum. Different areas use different textures, making the texture distinction quite clear.
③ Color: The buttons are white, which is both eye-catching and easy to operate. The rest of the front is frosted silver, which is not conspicuous but highlights the button area. The color scheme is harmonious and not monotonous, making it pleasing to the eye. The functions are also distinguished by color. The polished metal on the back adds a metallic texture.
④ Button Functions: The power button is located on the top of the device, and it can be slid left and right to control the power. The button is large and easy to operate. The front of the device features a circular integrated button, which mainly includes four functions: menu, forward, rewind, and play/pause. It is worth mentioning that there is also a hidden button that is a highlight of the button design of this MP3 player. In fact, there is a pressure sensor under the entire disc. The entire disc itself is a circular button. You can control functions such as song selection and volume by drawing a circle on the disc with your finger. It is very convenient. Especially when you need to select a song, you may need to press the fast forward button 10 times, but you only need to turn the disc once to do so. It is very convenient and quick.
III. Home Massage Chair: IKEA Kang Massage Chair YJK-801
Location: Suitable for people living at home, usually set up in homes, and sometimes in offices and public spaces.
Effects: Increases the body's immunity, relaxes the mind and body, regulates gastrointestinal function, improves bodily functions, promotes blood circulation, and helps prevent sub-health.
Human-computer interface analysis:
①Product Functions: Neck kneading massage (two sets of 6 massage heads rotating and kneading massage), back simulated human hand massage (simulated human hand massage, intelligent chip control), two-section arm airbag massage (two O-shaped airbags wrap around the arm, massage without dead angles), leg shaping machine design (relieves leg soreness and shapes perfect leg curves), foot acupressure massage (simulated human finger acupressure massage, relieves fatigue and relaxes muscles and tendons), and buttock airbag massage (promotes blood circulation and relaxes muscles and tendons).
② Hand Controller Interface: The hand controller interface is divided into six functional areas: power button, display screen, mode selection, fully automatic function, intensity adjustment, and body part selection. The entire operation button is divided into four parts: the two circular buttons on the top left and right are the power button and the fully automatic function button. The main power button is red and highly visible. The fully automatic function button is placed in a prominent position for easy user operation, making it simple and clear. The middle part is for selecting massage modes. The oval buttons select three massage modes, and the two mirror-symmetrical triangles adjust the speed. The lower area is for body part selection and intensity adjustment. The oval buttons select individual body parts, and the triangles adjust the intensity. The two oval buttons on the bottom left and right adjust the massage chair's recline and tilt. The main buttons are blue, creating a striking contrast with the black hand controller body, while the red main power button is prominent and clear.
