<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Marcia K. O'Malley</style></author><author><style face="normal" font="default" size="100%">Sevcik, Kevin S.</style></author><author><style face="normal" font="default" size="100%">Kopp, E</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Improved Haptic Fidelity via Reduced Sampling Period with an FPGA-Based Real-Time Hardware Platform </style></title><secondary-title><style face="normal" font="default" size="100%">ASME Journal of Computing and Information Science in Engineering</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">03/2009</style></date></pub-dates></dates><urls><related-urls><url><style face="normal" font="default" size="100%">http://mahilab.rice.edu/sites/default/files/publications/101-JCISE proof FINAL 2-09.pdf</style></url></related-urls></urls><number><style face="normal" font="default" size="100%">1</style></number><volume><style face="normal" font="default" size="100%">9</style></volume><abstract><style face="normal" font="default" size="100%">&lt;p&gt;A&lt;sup&gt; &lt;/sup&gt;haptic virtual environment is considered to be high-fidelity when the&lt;sup&gt; &lt;/sup&gt;environment is perceived by the user to be realistic. For&lt;sup&gt; &lt;/sup&gt;environments featuring rigid objects, perception of a high degree of&lt;sup&gt; &lt;/sup&gt;realism often occurs when the free space of the simulated&lt;sup&gt; &lt;/sup&gt;environment feels free and when surfaces intended to be rigid&lt;sup&gt; &lt;/sup&gt;are perceived as such. Because virtual surfaces (often called virtual&lt;sup&gt; &lt;/sup&gt;walls) are typically modeled as simple unilateral springs, the rigidity&lt;sup&gt; &lt;/sup&gt;of the virtual surface depends on the stiffness of the&lt;sup&gt; &lt;/sup&gt;spring model. For impedance-based haptic interfaces, the stiffness of the&lt;sup&gt; &lt;/sup&gt;virtual surface is limited by the damping and friction inherent&lt;sup&gt; &lt;/sup&gt;in the device, the sampling rate of the control loop,&lt;sup&gt; &lt;/sup&gt;and the quantization of sensor data. If stiffnesses greater than&lt;sup&gt; &lt;/sup&gt;the limit for a particular device are exceeded, the interaction&lt;sup&gt; &lt;/sup&gt;between the human user and the virtual surface via the&lt;sup&gt; &lt;/sup&gt;haptic device becomes nonpassive. We propose a computational platform that&lt;sup&gt; &lt;/sup&gt;increases the sampling rate of the system, thereby increasing the&lt;sup&gt; &lt;/sup&gt;maximum achievable virtual surface stiffness, and subsequently the fidelity of&lt;sup&gt; &lt;/sup&gt;the rendered virtual surfaces. We describe the modification of a&lt;sup&gt; &lt;/sup&gt;PHANToM Premium 1.0 commercial haptic interface to enable computation by&lt;sup&gt; &lt;/sup&gt;a real-time operating system (RTOS) that utilizes a field programmable&lt;sup&gt; &lt;/sup&gt;gate array (FPGA) for data acquisition between the haptic interface&lt;sup&gt; &lt;/sup&gt;hardware and computer. Furthermore, we explore the performance of the&lt;sup&gt; &lt;/sup&gt;FPGA serving as a standalone system for communication and computation.&lt;sup&gt; &lt;/sup&gt;The RTOS system enables a sampling rate for the PHANToM&lt;sup&gt; &lt;/sup&gt;that is 20 times greater than that achieved using the&lt;sup&gt; &lt;/sup&gt;&amp;ldquo;out of the box&amp;rdquo; commercial hardware system, increasing the maximum&lt;sup&gt; &lt;/sup&gt;achievable surface stiffness twofold. The FPGA platform enables sampling rates&lt;sup&gt; &lt;/sup&gt;of up to 400 times greater, and stiffnesses over 6&lt;sup&gt; &lt;/sup&gt;times greater than those achieved with the commercial system. The&lt;sup&gt; &lt;/sup&gt;proposed computational platforms will enable faster sampling rates for any&lt;sup&gt; &lt;/sup&gt;haptic device, thereby improving the fidelity of virtual environments.&lt;/p&gt;</style></abstract><notes><style face="normal" font="default" size="100%">&lt;pre&gt;Improved Haptic Fidelity Via Reduced Sampling Period With an FPGA-Based Real-Time Hardware Platform&lt;br /&gt;Marcia K. O'Malley, Kevin S. Sevcik, and Emilie Kopp, J. Comput. Inf. Sci. Eng. 9, 011002 (2009), DOI:10.1115/1.3072904&lt;br /&gt;&lt;br /&gt;&lt;br /&gt;&lt;/pre&gt;</style></notes></record></records></xml>