Stereo dynamic simulation system for the assembly

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Stereoscopic dynamic simulation system for engine assembly process

Abstract: Taking engine assembly process as an example, the hardware and software structure of stereoscopic dynamic simulation system are introduced in detail, and several problems needing attention in stereoscopic dynamic simulation are discussed

key words: engine; Stereopsis; Simulating the assembly of

parts is an important part of modern production process. The success of parts assembly is determined by the geometric constraints and the corresponding mechanical state of parts assembly. Geometric constraints can be described by motion trajectory analysis and animation

the geometric elements of the parts participating in the fitting are called assembly features, such as planes, cylinders, holes, etc. The fitting methods between assembly features are divided into four types according to geometric connection forms: coplanar reverse, hole column fitting, edge hole column fitting and ball sleeve fitting. Coplanar reverse indicates the plane contact between parts, but the normal direction is opposite; Hole column fit means that the cylinder and the round hole are concentric and in contact with each other; The fit of prisms and holes means that prisms and holes are concentric and in contact with each other; Ball sleeve fit means concentric fit between ball and sleeve. In the assembly of common engine parts, the most commonly used are hole column fit and coplanar reverse fit. There are relatively few edge hole column fits, and there is basically no ball sleeve fit

in the actual assembly process, due to the unclear space size of parts and components and the operation error in the assembly operation, the position error between the assembly parts will often be caused, resulting in the damage or jamming of the assembly parts. In order to ensure the success of the assembly operation, we must determine a reasonable assembly strategy, and it is best to simulate the assembly process on the computer before the actual assembly, so as to test the rationality and correctness of the assembly strategy

next, we will introduce a dynamic simulation system of engine assembly process based on stereo animation technology

but higher profits 1 hardware structure of stereoscopic dynamic simulation system

traditional dynamic simulation technology can more accurately describe the assembly process of parts, but because of the lack of depth in single view perspective, it is difficult to accurately judge the interference between parts. In practice, when we look at things, we always have a three-dimensional feeling, that is, we can feel the distance between objects, and also the distance between objects and us. When viewing an object, at the same time, two different images enter your left and right eyes through different angles. The human brain obtains the distance and depth by analyzing the two images. We can also experience this magical effect through computer-generated images, which is the so-called stereoscopic image generation technology. If a static stereoscopic image is generated, the traditional stereoscopic projection technology can be used. However, if you want to generate a large number of stereoscopic animation similar to the engine assembly process, you need to use the automatic generation technology of stereoscopic animation [1]

to observe stereoscopic animation on the computer, we need to adopt appropriate observation methods. There are many commonly used observation methods, such as the traditional red blue glasses method, the new liquid crystal glasses method and so on. The red blue glasses method does not need to add hardware equipment on the computer, but the new LCD observation equipment must add new hardware. The specific structure is shown in Figure 1 [2]:

Figure 1 the connection relationship of the new hardware

it can be seen from the figure that the new hardware includes control card, control box and stereo glasses. The control card is inserted into the expansion slot of the computer and connected with the computer display card through the signal line. The display and control box are directly connected with the control card. The new stereo glasses are wireless, so they do not need to be connected with the control box. It should be noted that in this hardware structure, the display device must be line by line

on the computer, 4.3.2 the sphere radius of the headform should be 95 ± 1mm. After adding these devices, we can observe the dynamic image with a sense of depth, and we can also observe the front and back relationship between objects on the computer screen. Of course, the observed content also needs to be an image generated from two viewpoints

2 software structure of engine stereoscopic dynamic simulation system

engine is a complex mechanism. In order to better describe the assembly process of the whole system, it is necessary to decompose this system into several relatively independent subsystems. According to the structural characteristics and functions of the described engine, the whole engine is divided into six parts. Figure 2 shows the structure of the stereo dynamic simulation system for engine assembly process. It is composed of controller, whole machine assembly subsystem, drive component assembly subsystem, cooling system assembly subsystem, body component assembly subsystem, intake and exhaust system assembly subsystem, supercharging system assembly subsystem and blackboard. The following is a brief introduction to each module

(1) controller

the controller is connected with each module and can call any module to work. It is the general command of the system and controls the operation of the whole system. Its main work is to generate and change the design environment according to the user input data and the current state, control the running sequence of each sub module, and solve the related problems between each sub module

in order to realize the above control, the controller adopts the control strategy of combining blackboard control method and menu driven control method

Figure 2 software structure of stereoscopic dynamic simulation system of stereoscopic engine

(2) drive component assembly subsystem

this subsystem uses stereoscopic dynamic simulation technology to demonstrate the correct assembly process of drive components

(3) cooling system assembly subsystem

this subsystem uses stereoscopic dynamic simulation technology to demonstrate the correct assembly process of the cooling system

(4) body component assembly subsystem

this subsystem uses stereoscopic dynamic simulation technology to demonstrate the correct assembly process of body components

(5) intake and exhaust system assembly subsystem

this subsystem uses stereoscopic dynamic simulation technology to demonstrate the correct assembly process of intake and exhaust system

(6) supercharging system assembly subsystem

this subsystem uses stereoscopic dynamic simulation technology to demonstrate the correct assembly process of the supercharging system

(7) blackboard

the blackboard is a working area of the system, and the information exchange between subsystems is carried out through the blackboard. Its main work is to record the initial requirements and intermediate calculation results. The content on the blackboard is dynamic and can be erased and rewritten at different stages of work

this system can not only demonstrate the independent assembly process of each part, but also demonstrate how to assemble each part into a whole

3 several key issues that need attention

when establishing a more complex stereoscopic dynamic simulation system like the engine, in addition to the common problems of general simulation, we also need to pay attention to the following issues:

(1) choose animation software suitable for stereoscopic simulation

animation software must have a good open structure and provide convenient development tools, In order to develop some practical tools according to the needs of stereoscopic simulation. In our application, 3ds Max is selected, and its development tools are used to develop parallax animation generation module, rendering control module and image synthesis module

before making parallax graphics, it is necessary to use this software system to make animation, including modeling, lighting, material design and action design, according to the characteristics of parts and the relationship between parts. The designed animation will be used as an input to the parallax animation generation module. At the same time, animation software also undertakes the rendering and saving of images

(2) parallax image generation and synthesis

there are two methods to generate parallax animation according to the existing animation. One is to adjust the camera manually; The other is to use the parallax animation generation module to generate parallax animation directly from the existing animation sequence. The parallax animation generation module automatically calculates the camera positions of the left and right viewpoints under the control of the controller according to the animation sequence in the animation software. That is, generate another animation sequence according to one animation sequence. The generated results can be saved on disk

when there is no camera movement, the first method can get good results. For the case of camera motion, especially the case that the camera should not decompose and the camera parameters should not change under ordinary temperature, the first method is a little inadequate, so the second method needs to be used

after generating the parallax animation images of the two sequences, it is necessary to synthesize the images of the two sequences. The method of synthesis is also related to the final observation method. If red and blue observation is used, the color of two sequence images is mainly processed; If you use stereoscopic glasses to observe, you can use the synthesis module we developed to synthesize directly. The image synthesis module can synthesize two sequences of images to form a parallax image sequence according to the requirements of users. The synthesized image sequence can be directly applied to stereoscopic dynamic simulation system

(3) interface design and synthesis

since the main purpose of this project is to help users get familiar with the assembly process of the engine and understand the possible problems in the assembly, the structure is wedge-shaped translational and manual rotary clamping. Therefore, the design of the interface should be based on liveliness. Based on this consideration, we selected a picture with rich colors as the background, and selected the representative parts in each subsystem as the representative of the system, and put them on the main interface. Moreover, different parts of the interface should have different actions and music according to the position of the mouse. Because the whole system has stereoscopic effect, all parts of the interface should also be designed as stereoscopic

after the interface is designed, the whole system needs to be synthesized according to the requirements of the system function and the needs of the interface. In this step, the stereoscopic animation, audio material and pictures of stereoscopic interface formed in the front need to be synthesized, together with text descriptions, to form a stereoscopic dynamic simulation software with rich control structure and beautiful interface. The dynamic simulation system of engine assembly process uses Authorware Multimedia software, and the control structure of the system is realized through the programming language provided by Authorware

the main interface of the system consists of six parts, namely, the whole machine assembly, driving parts, cooling system, body parts, intake and exhaust system and supercharging system

in the interface, each part is represented by its typical parts and is equipped with a prompt menu. Click any representative part to enter the assembly process demonstration of the corresponding part

4 conclusion

general dynamic simulation technology can describe the motion process of the mechanism, but because the dynamic graphics are generated using a single viewpoint projection, it is impossible to express the depth information, and it is also impossible to describe the occlusion relationship between various parts. Using stereoscopic projection technology can solve this problem in dynamic simulation. This paper introduces the software system and hardware system of stereoscopic dynamic simulation system, as well as several problems needing attention when establishing stereoscopic dynamic simulation system. Among these problems, the most difficult and time-consuming is the generation and synthesis of stereoscopic animation. At present, we are conducting a more in-depth study on this problem in order to improve the efficiency of developing stereoscopic dynamic simulation system. In practical application, the dynamic simulation system of stereoscopic engine assembly process has been well received

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