Virtual Assembly Environment Research Articles

Learnings from developing a custom virtual assembly environment for mountability issues of cooling cabinets

AbstractVarious industries use computer simulation for verifying product properties in early phases of development. Traditionally, such properties include the stability of mechanical structures or the efficiency of aircraft turbines. More recently, research also focuses on the mountability of industrial products using virtual assembly. While research on virtual assembly already started in the mid-1990s, the applicability in different industries remains largely unclear today. To advance the state-of-the-art, in this paper we present learnings from developing a virtual assembly environment for cooling cabinets.

A New Virtual Environment System for Large-Scale Complex Products Assembly

To deal with the problems of complicated process, difficult operation and low efficiency for large-scale complex products assembly, a new Virtual Assembly Environment System (VAES) was proposed, which applies Virtual Reality (VR) technology in the process of assembly planning and training. A series of key technologies were proposed, such as parallel rendering, stereoscopic display, geometrical correction, walking machine. A stereo video generator was developed to maintain real-time display and decrease costs. A geometrical correction method based on NURBS surface was presented. The system was applied in the process of satellite assembly, the result showed that it was feasible for the related research and application.

Gamification of assembly planning in virtual environment

PurposeThe purpose of this paper is to study the effect of the gamification of virtual assembly planning on the user performance, user experience and engagement.Design/methodology/approachA multi-touch table was used to manipulate virtual parts and gamification features were integrated into the virtual assembly environment. An experiment was conducted in two conditions: a gamified and a non-gamified virtual environment. Subjects had to assemble a virtual pump. The user performance was evaluated in terms of the number of errors, the feasibility of the generated assembly sequence and the user feedback.FindingsThe gamification reduced the number of errors and increased the score representing the number of right decisions. The results of the subjective and objective analysis showed that the number of errors decreased with engagement in the gamified assembly. The increase in the overall user experience reduced the number of errors. The subjective evaluation showed a significant difference between the gamified and the non-gamified assembly in terms of the level of engagement, the learning usability and the overall experience.Research limitations/implicationsThe effective learning retention after training has not been tested, and longitudinal studies are necessary. The effect of the used gamification elements has been evaluated as a whole; further work could isolate the most beneficial features and add other elements that might be more beneficial for learning.Originality/valueThe research reported in this paper provides valuable insights into the gamification of virtual assembly using a low-cost multi-touch interface. The results are promising for training operators to assemble a product at the design stage.

Intelligent Analysis Method of Assembly Process Based on Semantic Elements

The assembly process file is a direct expression of the product assembly design intent. In order to improve the quality and efficiency of the assembly, the 3D model of the product and resources needs to be introduced into the virtual assembly environment. However, the assembly process is verified and optimized by assembly simulation. In order to realize the intelligent analysis of assembly process files and the automation of assembly simulation, an intelligent analysis method of assembly process based on semantic elements is proposed. This article takes the assembly process documentation of complex products as the research object. An improved TF-IDF algorithm is proposed to automatically extract key semantic elements in the assembly process file. We quickly resolve previous assembly process data by building assembly key semantic corpora. An assembly semantic dependency tree algorithm based on maximum entropy is proposed to automatically reason the logical relationship of each assembly phrase in the assembly process statement. According to the above algorithm, the assembly semantic intelligent analysis system is developed. The assembly process of a certain type of ground weapon system is taken as an example to verify the system. And the intelligent analysis of the product process file is realized which lays a foundation for realizing the semantic driving of product assembly simulation.

Virtual fire drill system supporting co-located collaboration

Background Due to the restriction of display mode, in most of the virtual reality systems with multiple people in the same physical space, the program renders the scene based on the position and perspective of the one user, so that other users just see the same scene, resulting in vision disorder. Methods To improve experience of multi-user co-located collaboration, in this study, we propose a fire drill system supporting co-located collaboration, in which three co-located users can collaborate to complete the virtual firefighting mission. Firstly, with multi-view stereoscopic projective display technology and ultra wideband (UWB) technology, co-located users can roam independently and watch virtual scenes through the correct perspective view based on their own position by wearing dedicated shutter glasses, thus carrying out different virtual tasks, which improves the flexibility of co-located collaboration. Secondly, we design simulated firefighting water-gun using the micro-electromechanical system sensor, through which users can interact with virtual environment, and thus provide a better interactive experience. Finally, we develop a workbench including a holographic display module and multi-touch operation module for virtual scene assembly and virtual environment control. Results The controller can use the workbench to adjust the virtual layout in real time, and control the virtual task process to increase the flexibility and playability of system. Conclusions Our work can be employed in a wide range of related virtual reality applications.

An improved collision detection algorithm based on OBB swept volume for virtual assembly

The speed and precision of collision detection are the main concerns in a virtual assembly environment. The calculation time and accuracy of conventional collision detection algorithms need to be improved. This paper introduces an improved algorithm called OSV (OBB swept volume) based on OBB (oriented bounding box) for continuous collision detection. A bounding volume boxes tree is built by using the OBB bounding boxes model. The rough collision detection is realized by separating axis testing. Then by the exact intersection test algorithm based on the triangular patches, the objects that might be on a collision course with others are further retested. Experiment results show that the algorithm works accurately and has a higher accuracy rate than other similar methods.

The Construction of Autonomous Virtual Hand in Virtual Assembly Environments

The Construction of Autonomous Virtual Hand in Virtual Assembly Environments

Design Improvement of Assembly Workplace through Ergonomic Simulation and Analysis Using DELMIA

The aim of this research is to demonstrate the ergonomic process modeling and simulation of manual assembly work through virtual assembly approach in order to present workplace and process improvement prior to their physical prototyping. In this regard, a case study has been carried out to analyze an assembly workplace of a diesel engine by ergonomics simulation and virtual assembly approach. DELMIA, a software tool, has been exploited for the ergonomic simulation and analysis in virtual assembly environment. The case study demonstrates several improvements in the ergonomics of the operators performing assembly on production line of the diesel engine. The assembly process of last few stations of the diesel engine simulated and analyzed on DELMIA in order to exhibit the advantages of the virtual assembly approach to the workplace deign and saving of process time and energy expenditure of operator. On last station of the engine assembly line, parts are assembled relatively at higher and complex positions and it is difficult for an operator to assembly them. Since, the assembly is carried out on conveyor; it is not convenient to change the height of conveyor to overcome the problem. Therefore, height of the floor of last work station is altered / increased. In order to achieve the increased floor height, a number of benches of variable heights are placed on the floor on the last working station one by one in the simulation environment and simulation of the process is carried out. The simulation results show that the ergonomics of operators have significantly changed by altering working height of the operator. Simulation of second last and other working station has also been performed by altering the height of the floor, but no improvements in the ergonomics of the operator observed for these stations

A framework for interactive assembly task simulationin virtual environment

With the development of the virtual reality technology, users can perform interactive assembly tasks by direct manipulation in virtual environment. However, most of the current studies mainly focus on the function of virtual assembly system without fully considering the interaction efficiency and user experience. As a result, users usually feel depressed in performing complex assembly tasks. A novel framework for interactive assembly task simulation is proposed to address this problem in this paper. The framework is implemented from three aspects: (1) the interaction information related to the assembly operations is integrated into virtual environment; (2) the user’s intentions are captured according to the gestures and movements of users and the integrated interaction information of components assembled; and (3) the interaction behaviors of components intelligently and automatically are simulated in accordance with the user’s intentions. According to the analysis of the assembly process, dynamic and static interaction behaviors are designed. The object’s dynamic behavior containing a series of standard actions is used to assist users in performing interaction tasks. The user completes an assembly task by establishing the connection relationship between objects, which can be implemented based on the object’s static interaction behavior. A virtual assembly task is constructed to evaluate the performance of the method, and the results of usability test confirm that the method proposed in this paper can improve the efficiency of human-computer interaction and user experience in a virtual assembly environment.

Feature Recognition for Virtual Environments

This paper demonstrates methods to recognize 3D designed features for virtual environments and apply them to Virtual assembly. STEP is a standard of Product data Exchange for interfacing different design systems, but it cannot be used as input for virtual environments. In order to use feature data in virtual assembly environments, main data source from a STEP file should be recognized and features should be re-built. First, Attributed Adjacency Graph (AAG) is used to analyze and express the boundary representation; second, a feature-tree of a part is constructed; third, using the AAG and feature-tree as inputs, we analyze and extract of features with a feature recognition algorithm; finally, various levels of detail of object geometric shapes is built and expressed in XML for virtual assembly applications.

Development of Virtual Repair Training System of Transmission

Aiming at the problem on complex structure and lack of effective training methods of the transmission developed a set of transmission interactive virtual maintenance training system. Used the software of Solidworks and 3D MAX to build a virtual prototype of the transmission, and then making simplification and rendering, by converting the coordinate system and the viewpoint to achieve the construction of virtual assembly environment. By controlling the node and the demolition path in EON, the virtual interactive simulation is achieved. Through collision the detection and path settings, the virtual interactive roaming is achieved. Determined the scoring rules, scoring criteria, assessment standards and other key technologies, achieved four functions of demonstration, learning, training and assessment. It has a great practical significance to improve the training effect, effectively solved the high cost of training, teaching efficiency and other issues.

VREM: An advanced virtual environment for micro assembly

Micro assembly involves the assembly of micron-sized devices. Given the complexity of this domain, the role of virtual environments becomes important as they provide a basis to propose and compare assembly alternatives virtually prior to physical assembly. This paper proposes an integrated approach which includes the use of virtual reality-based assembly environments that interface with physical micro assembly environments. Such an approach can be an intrinsic part of a collaborative manufacturing framework that seeks to support the rapid assembly of micro devices. In this paper, the design of VREM (Virtual Reality based Environment for Micro Assembly) is discussed which is based on this integrated approach involving use of virtual and physical resources.

Virtual human hybrid control in virtual assembly and maintenance simulation

To improve virtual human motion simulation and generation efficiency in virtual assembly and maintenance (A&M) environment, based on a detailed analysis of virtual human control methods in A&M simulation, a virtual human hybrid control method is presented in this paper. In the proposed method, virtual human A&M motion is divided into three types: primitive motion (PM), fine motion (FM) and transitional motion (TM). For PM, a real operator can drive a virtual human in real time for A&M operation via virtual reality interactive devices; in this way, the PM can be quickly generated. As for FM and TM generation, their semantic-level parameterized models including engineering attributes are created; then, their generation processes are represented; in the generation processes, a virtual human posture automatic reasoning model is established to support auto-generating A&M motion. The approaches in the present study are validated by generating virtual human motions in partial assembly process of auto engine. Results show that the proposed method can improve A&M motion simulation efficiency and support the fast generation of realistic A&M motion.

A collisions evaluation method in virtual environment for collaborativeassembly

Collision detection is critical for collaborative assembly simulation to assist design processing. However, collisions between polygonal models may not reflect collisions between real objects in reality because of polygonal approximation and designed tolerance. This problem reduces the reliability of simulation in collaborative assembly and sometimes even results in wrong conclusions. To solve the problem, we propose a novel collision evaluation algorithm based on generalized penetration depth, approximation information, and tolerance information. Given two interfered polygonal models, generalized penetration depth is calculated using relative motion information. Then two thresholds, which are based on approximation information and tolerance information, are integrated to evaluate collisions between polygonal models. In order to distinguish the status of collisions for further analysis, the collisions between polygonal models are categorized into three types by evaluation algorithm, namely real collision, potential collision, and fake collision. Computational efficiency and accuracy of the evaluation algorithm are verified in a virtual collaborative assembly environment.

Research and Realization of Virtual Assembly Environment of Armored Vehicle Transmission Based on Dual-Channel Projection

The characteristics of assembly of vehicle transmission have been analyzed in this paper. General structure of PC-cluster virtual assembly environment of vehicle transmission based on dual-channel projection was described in detail. According to the characteristics of virtual assembly, analysis on technology of spectra stereoscopic display was performed. A geometric correction method of mechanic correction combined with software correction was proposed on the basis of arrangement form of curtain wall and the type of projector. Dual-channel synchronization mechanism in combination with the principle of PC-cluster was put forward. The application of a practical example in the virtual environment was realized for verifying the aforesaid methods and technologies.

Propellant Filling Equipment Simulation for Virtual Assembly

3D models of propellant filling equipment were constructed by using Autodesk Inventor, and assembly relation model was established by using connection graph method. Movement attribute was set and the models were romanced in Multigen Creator. A virtual scene of propellant filling equipment was set up, and assembly process demonstration and interactive operation simulation were achieved by using Vega Prime. Maintenance personnel training in the virtual assembly environment gets a good result.

Universal mechanism modeling method in virtual assembly environment

Motion simulation and performance analysis of mechanism are important methods for analyzing assembly quality after finishing assembly simulation in virtual assembly environment. However, most simulation systems have no function of mechanism motion simulation due to the randomicity of mechanism and lack of universal mechanism modeling method. In order to realize the simulation of any mechanism after finishing assembly simulation in a virtual environment, a new universal mechanism modeling method is presented. Two main models are contained in the mechanism model: information model and mathematical model. Firstly, the information model of mechanism is proposed to describe the data structure of mechanism which contains bottom geometry data, information of constraint, link, kinematic pair and physical data. Because the object of mechanism simulation is the assembly, which is assembled during the process of assembly simulation, the information of mechanism can be obtained automatically through mechanism automatic search method. Secondly, mathematical model of mechanism is presented. The mathematical model uses mathematical method to express the mechanism. In order to realize the automatic expression of any random mechanism, basic constraint library is presented, consequently random mechanism can be described based on the basic constraint library. Finally, two examples are introduced to validate the method in the prototype system named VAPP(Virtual Assembly Process Planning). The validation result shows that the mechanism modeling provides a universal modeling method for mechanism motion simulation in virtual assembly environment. This research has important effect on the development both of mechanism motion simulation and virtual assembly.

Design and implementation of a haptic‐based virtual assembly system

PurposeHaptics can significantly enhance the user's sense of immersion and interactivity. Especially in an assembly task, haptic feedback can help designers to have a better understanding of virtual objects and to increase task efficiency. The purpose of this paper is to investigate the design and implementation of a haptic‐based virtual assembly system (HVAS).Design/methodology/approachA multi‐thread system structure was designed, an automatic data integration interface was developed to transfer geometry, topology, assembly and physics information from a computer‐aided design system to virtual reality application, and a hierarchical constraint‐based data model and scene graph structure was designed to construct the virtual assembly environment. Unlike traditional virtual assembly systems based on collision detection or geometry constraint only, a physics‐based modeling approach combining with haptic feedback and geometry constraint was undertaken to realize and guide the realistic assembly process. When two parts collide into each other, the force and torque can be computed and provide feedback, and a spring‐mass model is used to prevent penetration and simulate dynamic behaviour. When two parts are close enough to each other and the assembly simulation state is activated, a geometry constraint can be captured, an attractive force can be generated to guide the user to assemble the part along the correct position, and the repulsive force can also be generated to realize the mating process as natural and realistic as in real life.FindingsThe implementation details and application examples demonstrate that haptic‐based virtual assembly is a valuable tool for assembly design and process planning.Originality/valueThe paper presents an HVAS.

A new type haptics-based virtual environment system for assembly training of complex products

Virtual reality (VR)-based assembly training has been an interesting topic for the last decades. Generally, there are two shortcomings for nowadays virtual assembly training systems. One is that the operators cannot move around the virtual environment in a natural way as people activity in the real world: they are constrained in a fixed position or can only move in a limited space. The other is that most of the virtual assembly training systems are based on geometry constraint modeling only, which lacks haptics feedback. A new type haptics-based virtual environment system for assembly training of complex products is described in this paper. A new low-cost motion simulator is designed and integrated with the virtual environment to realize free walking by human. An automatic data integration interface is developed to transfer geometry, topology, assembly, and physics information from a computer-aided design system to a VR application, and a hierarchical constraint-based data model is rebuilt to construct the virtual assembly environment. Physics-based modeling and haptics feedback are undertaken to simulate the realistic assembly operations. The application examples and evaluation experiments demonstrate that both motion simulator and haptics have great value for training of assembly processes.

Context Perception Mechanism in Virtual Assembly Environment

The structure of virtual assembly environment and the pattern of response message was represented based on the Multi-Agent theory; the context perception mechanism in virtual assembly environment was analyzed, and a perception algorithm was put forward. The result showed that cognitive burden of human had been shared by virtual assembly environment in reason; the efficiency of assembly manipulation in virtual assembly environment had been increased; the level of human-computer interaction had been improved.