Application of digital 3D human body model in automobile layout CAD design1

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Application of digital 3D human body model in automobile layout CAD design1 [Copy link]

1 Introduction

Automobiles are very complex products that need to meet various performance requirements. Their design and development process is also composed of many different work stages, and each work stage requires the use of a variety of different design verification technologies. Only by using new technologies to fully integrate the entire product development process and its different working methods can the purpose of accelerating and optimizing design be achieved.

Digital virtual technology integrates various computer technologies and gives full play to their application potential, so that product development and design can be reliably completed in the computer system in the form of digital models to complete product design and verification. In automobile development, virtual technology helps decision-makers make decisions and track and manage design plans as early as possible; helps to strengthen cooperation in different places and jointly solve technical problems; helps to conduct repeated verification and verification before manufacturing prototypes, so as to find and avoid design errors as early as possible; helps to obtain product information as early as possible before the product goes into production for market research. Digital virtual technology throughout the entire product development process can optimize product characteristics in a comprehensive and systematic manner, greatly shorten the development cycle, greatly reduce development costs, improve product quality, and ultimately improve the competitiveness of enterprises in the market.

2. Car interior layout design

The interior layout of a car is a complex system engineering from conception, design to verification. When arranging, many constraints and ergonomic requirements must be considered. The interior layout of a car is a "people-centered" design, that is, it is people-centered and uses ergonomics to achieve a harmonious design concept of people-car-environment under certain constraints. The interior layout design of a car is a design process of arranging multiple aspects at the same time, and it is also a design process of constantly and repeatedly seeking the optimal solution.

The main tasks of the interior layout of the car are: ① Determine the main layout dimensions of the model: passenger layout; determine the main dimensions of the whole vehicle; layout of the pedal, shift lever and handbrake position; layout of the steering wheel and steering column; layout of the luggage compartment; side window glass; top cover position; layout of the seat and instrument panel, etc. ② Ergonomics research: ensure the living comfort and safety of the driver and passengers, as well as the driver's convenience of operation and good vision, etc. ③ Regulatory compliance verification: windshield area and wiper layout; hand reach and interface; instrument panel visual range; internal and external rearview mirror field of view; seat belt fixing points, etc. While meeting these requirements, it is also necessary to minimize the vehicle mass, increase the interior space, and improve the economic performance of the vehicle. In traditional design, engineers use two-dimensional human body templates to design the interior layout of the car on a two-dimensional main drawing board. It is impossible to evaluate and verify the spatial position of the pedal, shift lever, steering wheel, maneuverability, sitting posture, and field of view in advance. Only after the physical prototype is made and a certain proportion of people perform actual driving operations can the verification be completed.

Nowadays, due to the development and application of computer technology, CAD methods have been widely used in automobile development for three-dimensional digital design, with three-dimensional data as the main line and virtual prototypes used to optimize product design and verification processes. Therefore, digital three-dimensional human body models have correspondingly exerted their potential and advantages in the ergonomic simulation and analysis of the interior layout of automobiles.

3 Digital 3D human body model

At every stage of the product cycle, people are the most important factor. Digital 3D human models can be effectively applied in the entire life cycle of automotive virtual design and manufacturing, from the initial concept design to the final product verification.

Digital human model technology can assist designers in determining the performance of people in the corresponding working environment, determine the size/shape/function of the human body and its positioning, and meet the requirements of comfort and safety standards. As shown in Figure 1, in the virtual CAD design data, this virtual human model can be transferred to complete the operation tasks and analysis work. Through the three-dimensional human model, the digital human body and electronic prototype can be used to simulate and analyze the elements related to people, such as human operability, comfort, visibility and other important design elements. The application of digital three-dimensional human model in the process of automobile interior layout can improve design efficiency and design quality; improve safety and ergonomics performance; reduce the manufacturing and verification work and cycle of physical prototypes.

Figure 1 Digital 3D human body model used in CAD design

Boeing, GM, Daimler-Chrysler and other large aircraft and automobile companies have been applying digital 3D human models more and more widely in all aspects and stages of the product life cycle. Large software companies such as CATIA and EDS have also launched digital 3D human body modules for users to use and continuously supplement and improve them.

Taking the human model module (Manikin) of CATIA as an example, the main functions of the digital 3D human model are briefly explained. The 3D human model includes 4 submodules: the Human Builder module generates a human model that can match the product; the Human Measurement Edit module can adjust the size of each part of the human model proportionally; the Human Activity Analysis module evaluates the human limbs from static postures to complex dynamic movements; the Human Posture Analysis module analyzes various postures of the human body. This human model includes 104 sets of human measurement data; 100 unconstrained connections; 148 degrees of freedom; various posture contours; models including hand models, spine models, shoulder models, hip models, etc. with all joints; can express the constraints of joint activities and the upper and lower limits of movement and can be adjusted. This module has the following uses: measuring human dimensions; field of view analysis; sitting posture analysis; movement comfort angle analysis; reach analysis; lifting, lowering and carrying analysis; design interference inspection; motion simulation, etc.