Effect of weight perception on human performance in a haptic-enabled virtual assembly platform

Virtual assembly platforms (VAPs) provide a means to interrogate product form, fit and function thereby shortening the design cycle time and improving product manufacturability while reducing assembly cost. VAPs lend themselves to training and can be used as offline programmable interfaces for planning and automation. Haptic devices are increasingly being chosen as the mode of interaction for VAPs over conventional glove-based and 3D-mice, the key benefit being the kinaesthetic feedback users receive while performing virtual assembly tasks in 2D/3D space leading to a virtual world closer to the real world. However, the challenge in recent years is to understand and evaluate the addedvalue of haptics. This paper reports on a haptic enabled VAP with a view to questioning the awareness of the environment and associated assembly tasks. The objective is to evaluate and compare human performance during virtual assembly and real-world assembly, and to identify conditions that may affect the performance of virtual assembly tasks. In particular, the effect of weight perception on virtual assembly tasks is investigated

An evaluation of physics engines and their application in haptic virtual assembly environments

Virtual Reality (VR) applications are employed in engineering situation to simulate real and artificial situations where the user can interact with 3D models in real time. Within these applications the virtual environment must emulate real world physics such that the system behaviour and interaction are as natural as possible and to support realistic manufacturing applications. As a consequence of this focus, several simulation engines have been developed for various digital applications, including VR, to compute the physical response and body dynamics of objects. However, the performance of these physics engines within haptic-enabled VR applications varies considerably. In this study two third party physics engines - Bullet and PhysXtm- are evaluated to establish their appropriateness for haptic virtual assembly applications. With this objective in mind five assembly tasks were created with increasing assembly and geometry complexity. Each of these was carried out using the two different physics engines which had been implemented in a haptic-enabled virtual assembly platform specifically developed for this purpose. Several physics-performance parameters were also defined to aid the comparison. This approach and the subsequent results successfully demonstrated the key strengths, limitations, and weaknesses of the physics engines in haptic virtual assembly environments

A new methodology to evaluate the performance of physics simulation engines in haptic virtual assembly

Purpose – In this study, a new methodology to evaluate the performance of physics simulation engines (PSEs) when used in haptic virtual assembly applications is proposed. This methodology can be used to assess the performance of any physics engine. To prove the feasibility of the proposed methodology, two-third party PSEs – Bullet and PhysXtm – were evaluated. The paper aims to discuss these issues. Design/methodology/approach – Eight assembly tests comprising variable geometric and dynamic complexity were conducted. The strengths and weaknesses of each simulation engine for haptic virtual assembly were identified by measuring different parameters such as task completion time, influence of weight perception and force feedback. Findings – The proposed tests have led to the development of a standard methodology by which physics engines can be compared and evaluated. The results have shown that when the assembly comprises complex shapes, Bullet has better performance than PhysX. It was also observed that the assembly time is directly affected by the weight of virtual objects. Research limitations/implications – A more comprehensive study must be carried out in order to evaluate and compare the performance of more PSEs. The influence of collision shape representation algorithms on the performance of haptic assembly must be considered in future analysis. Originality/value – The performance of PSEs in haptic-enabled VR applications had been remained as an unknown issue. The main parameters of physics engines that affect the haptic virtual assembly process have been identified. All the tests performed in this study were carried out with the haptic rendering loop active and the objects manipulated through the haptic device.CONACYT (National Science and Technology Council of Mexico) research grant CB-2010-01-154430 and EPSRC/IMRC grants 113946 and 11243

Assembly-based rapid production of near net shape components through octree decomposition of 3D models

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Development of a haptic virtual reality system for assembly planning and evaluation

AbstractVirtual reality systems can be used to simulate, analyze and optimize manufacturing processes including assembly. Haptic technologies enable the user to feel the force feedback from the virtual environment, leading to a more intuitive and natural way to simulate the assembly process during the design phase of new components even before any physical prototype is created. This paper presents the development of a haptic virtual reality platform to perform, plan and evaluate virtual assemblies of components. The system allows real-time manipulation and interaction of virtual components. Physics simulation engines are used to enable physic based behavior and collision detection of virtual objects in the virtual environment. One of the outstanding characteristics of the proposed platform is that the user can modify various simulation parameters during run-time, such as the weight of virtual objects, model representation algorithm and the physics simulation engine being used, which is very important in order to evaluate the influence of each parameter on the performance of virtual assembly tasks