Browsing by Author "Yu, Wai"
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Item A peer-to-peer architecture for collaborative haptic assembly(2006) Iglesias, Rosa; Casado, Sara; Gutiérrez, Teresa; García-Alonso, Alejandro; Yap, Kian Meng; Yu, Wai; Marshall, Alan; PROMETAL; CIRMETALVirtual Environments using haptic devices have proved useful for assembly/disassembly simulation of mechanical components. To date most haptic virtual environments are stand-alone. Collaborative Haptic Virtual Environments (CHVEs) are distributed across a number of users via a network, such as the Internet. These present new challenges to the designer, such as consistency of the virtual environments, user-user haptic interaction, and scalability. The system described in this paper considers the CHVEs to be distributed over a packet-switched network such as the Internet. It gives priority to the validation of interactions between objects grasped by users; guarantees consistency across different users' virtual environments. The paper explains the components used and the consistency-maintenance scheme that guarantees the consistency of the virtual scene in the remote nodes. Consistency and force feedback results are also discussed. Results presented show the system maintains a consistent and satisfactory response when network incurs delay or packet jitter.Item Simultaneous remote haptic collaboration for assembling tasks(2008-01) Iglesias, Rosa; Casado, Sara; Gutiérrez, Teresa; García-Alonso, Alejandro; Yu, Wai; Marshall, Alan; PROMETAL; CIRMETALStand-alone virtual environments (VEs) using haptic devices have proved useful for assembly/disassembly simulation of mechanical components. Nowadays, collaborative haptic virtual environments (CHVEs) are also emerging. A new peer-to-peer collaborative haptic assembly simulator (CHAS) has been developed whereby two users can simultaneously carry out assembly tasks using haptic devices. Two major challenges have been addressed: virtual scene synchronization (consistency) and the provision of a reliable and effective haptic feedback. A consistency-maintenance scheme has been designed to solve the challenge of achieving consistency. Results show that consistency is guaranteed. Furthermore, a force-smoothing algorithm has been developed which is shown to improve the quality of force feedback under adverse network conditions. A range of laboratory experiments and several real trials between Labein (Spain) and Queen's University Belfast (Northern Ireland) have verified that CHAS can provide an adequate haptic interaction when both users perform remote assemblies (assembly of one user's object with an object grasped by the other user). Moreover, when collisions between grasped objects occur (dependent collisions), the haptic feedback usually provides satisfactory haptic perception. Based on a qualitative study, it is shown that the haptic feedback obtained during remote assemblies with dependent collisions can continue to improve the sense of co-presence between users with regard to only visual feedback.