Multi-rate Control Architectures for Dextrous Haptic Rendering in Cooperative Virtual Environments

Author(s):  
M. Fotoohi ◽  
S. Sirouspour ◽  
D. Capson
2009 ◽  
Vol 18 (5) ◽  
pp. 340-360 ◽  
Author(s):  
Jong-Phil Kim ◽  
Beom-Chan Lee ◽  
Hyungon Kim ◽  
Jaeha Kim ◽  
Jeha Ryu

This paper proposes a novel, accurate, and efficient hybrid CPU/GPU-based 3-DOF haptic rendering algorithm for highly complex and large-scale virtual environments (VEs) that may simultaneously contain different types of object data representations. In a slower rendering process on the GPU, local geometry near the haptic interaction point (HIP) is obtained in the form of six directional depth maps from virtual cameras adaptively located around the object to be touched. In a faster rendering process on the CPU, collision detection and response computations are performed using the directional depth maps without the need for any complex data hierarchy of virtual objects, or data conversion of multiple data formats. To efficiently find an ideal HIP (IHIP), the proposed algorithm uses a new “abstract” local occupancy map instance (LOMI) and the nearest neighbor search algorithm, which does not require physical memory for storing voxel types during online voxelization and reduces the search time by a factor of about 10. Finally, in order to achieve accurate haptic interaction, sub-voxelization of a voxel in LOMI is proposed. The effectiveness of the proposed algorithm is subsequently demonstrated with several benchmark examples.


Author(s):  
Ryan A. Pavlik ◽  
Judy M. Vance

Haptic force-feedback can provide useful cues to users of virtual environments. Body-based haptic devices are portable but the more commonly used ground-based devices have workspaces that are limited by their physical grounding to a single base position and their operation as purely position-control devices. The “bubble technique” has recently been presented as one method of expanding a user's haptic workspace. The bubble technique is a hybrid position-rate control system in which a volume, or “bubble,” is defined entirely within the physical workspace of the haptic device. When the device's end effector is within this bubble, interaction is through position control. When the end effector moves outside this volume, an elastic restoring force is rendered, and a rate is applied that moves the virtual accessible workspace. Publications have described the use of the bubble technique for point-based touching tasks. However, when this technique is applied to simulations where the user is grasping virtual objects with part-to-part collision detection, unforeseen interaction problems surface. Methods of addressing these challenges are introduced, along with discussion of their implementation and an informal investigation.


2014 ◽  
Vol 8 (3) ◽  
pp. 319-331 ◽  
Author(s):  
Ravikiran B. Singapogu ◽  
Christopher C. Pagano ◽  
Timothy C. Burg ◽  
Paul G. Dorn ◽  
Ron Zacharia ◽  
...  

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