%0 Journal Article %J ACM Transactions on Applied Perception %D 2009 %T Negative Efficacy of Fixed Gain Error Reducing Shared Control for Training in Virtual Environments %A Yanfang Li %A Volkan Patoglu %A O'Malley, M.K. %X

Virtual reality with haptic feedback provides a safe and versatile practice medium for many manual control tasks. Haptic guidance has been shown to improve performance of manual control tasks in virtual environments; however, the efficacy of haptic guidance for training in virtual environments has not been studied conclusively. This article presents experimental results that show negative efficacy of haptic guidance during training in virtual environments. The haptic guidance in this study is a fixed-gain error-reducing shared controller, with the control effort overlaid on the dynamics of the manual control task during training. Performance of the target-hitting manual control task in the absence of guidance is compared for three training protocols. One protocol contained no haptic guidance and represented virtual practice. Two protocols utilized haptic guidance, varying the duration of exposure to guidance during the training sessions. Exposure to the fixed-gain error-reducing shared controller had a detrimental effect on performance of the target-hitting task at the conclusion of a month-long training protocol, regardless of duration of exposure. While the shared controller was designed with knowledge of the task and an intuitive sense of the motions required to achieve good performance, the results indicate that the acquisition of motor skill is a complex phenomenon that is not aided with haptic guidance during training as implemented in this experiment.

%B ACM Transactions on Applied Perception %V 6 %8 01/2009 %> https://mahilab.rice.edu/sites/default/files/publications/103-Li-Patoglu-O%27Malley_TAP_6%281%29_2009FINAL.pdf %0 Journal Article %J IEEE Transactions on Haptics %D 2009 %T Passive and Active Discrimination of Natural Frequency of Virtual Dynamic System %A Ali Israr %A Yanfang Li %A Volkan Patoglu %A O'Malley, M.K. %B IEEE Transactions on Haptics %V 2 %P 40-51 %8 02/2009 %R 10.1109/TOH.2008.21 %> https://mahilab.rice.edu/sites/default/files/publications/102-Israr-Li-Patoglu-O%27Malley_IEEEToH_2%281%29_2009FINAL.pdf %0 Conference Proceedings %B Third Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperation Systems, (WHC'09) %D 2009 %T Progressive shared control for training in virtual environments %A Yanfang Li %A Joel C. Huegel %A Volkan Patoglu %A O'Malley, M.K. %K Haptic interface %K performance %K shared control %K training %B Third Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperation Systems, (WHC'09) %I IEEE %C Salt Lake City, UT, USA %P 332-337 %8 03/2009 %> https://mahilab.rice.edu/sites/default/files/publications/109-LiPSC-WHC.pdf %0 Conference Proceedings %B 16th Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (HAPTICS) %D 2008 %T Passive and active kinesthetic perception just-noticeable-difference for natural frequency of virtual dynamic systems %A Yanfang Li %A Ali Israr %A Volkan Patoglu %A O'Malley, M.K. %K Haptic interfaces %K visual perception %X

This paper investigates the just-noticeable-difference (JND) for natural frequency of virtual second order dynamic systems. Using a one degree-of-freedom haptic device, visual and/or haptic sensory feedback were presented during interactions with the system. Participants were instructed to either perceive passively or actively excite the system in order to discriminate natural frequencies. The JND for this virtual resonance task ranged from 3.99 % to 6.96 % for reference frequencies of 1 Hz and 2 Hz. Results show that sensory feedback has a significant effect on JND in passive perception, with combined visual and haptic feedback enabling the best discrimination performance. In active perception, there is no significant difference on JND with haptic and combined visual and haptic feedback. There is also no significant difference between active perception and passive perception for this JND experiment. The presentation of systems with equivalent natural frequencies but different spring stiffness resulted in no large bias toward larger stiffness and no significant difference in JND for equivalent systems. This finding indicates that human participants do not discriminate natural frequency based on the maximum force magnitude perceived, as indicated by prior studies.

%B 16th Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (HAPTICS) %I IEEE %C Reno, NE, USA %P 25 - 31 %8 03/2008 %G eng %U http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4479908 %M 9872945 %R 10.1109/HAPTICS.2008.4479908 %> https://mahilab.rice.edu/sites/default/files/publications/58-HapticSymposium2008_Li.pdf %0 Conference Proceedings %B Second Joint EuroHaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems, (WHC'07) %D 2007 %T Towards just noticeable differences for natural frequency of manually excited virtual dynamic systems %A Yanfang Li %A Volkan Patoglu %A Huang, Deborah %A O'Malley, M.K. %K Display devices %K Dynamical systems %K Natural frequencies %X

This paper explores the experiment design to determine a human's ability to discriminate the natural frequency of manually excited virtual dynamic systems. We use a one degree-of-freedom haptic interface with a coupled graphical display to render a virtual mass-spring system, which is excited by the human operator using his/her dominant hand. The results from the preliminary experiment indicate a JND value of approximately 8%. However, results also indicate that excitation strategies have a significant effect on the discrimination threshold determination of this dynamic property. In this paper, along with a discussion of the preliminary results, a refined experiment design that accounts for different factors influencing the discrimination of manually excited natural frequency is presented. © 2007 IEEE.

%B Second Joint EuroHaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems, (WHC'07) %I IEEE %C Tsukuba, Japan %P 569 - 570 %8 03/2007 %G eng %U http://dx.doi.org/10.1109/WHC.2007.118 %R 10.1109/WHC.2007.118 %> https://mahilab.rice.edu/sites/default/files/publications/59-00%20-%20Towards%20Just%20Noticeable%20Differences%20for%20Natural%20Frequency%20of%20Manually%20Excited%20Virtual%20Dynamic%20Systems.pdf %0 Conference Proceedings %B Proceedings of EuroHaptics 2006 %D 2006 %T Shared Control for Training in Virtual Environments: Learning Through Demonstration? %A Yanfang Li %A Volkan Patoglu %A O'Malley, M.K. %B Proceedings of EuroHaptics 2006 %G eng %> https://mahilab.rice.edu/sites/default/files/publications/73-00%20-%20Li_Patoglu_OMalley_Eurohaptics06.pdf %0 Journal Article %J Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME %D 2006 %T Shared control in haptic systems for performance enhancement and training %A O'Malley, M.K. %A Abhishek Gupta %A Gen, Matthew %A Yanfang Li %K Control equipment %K Damping %K Data reduction %K Haptic interfaces %K Robotics %K Robots %X

This paper presents a shared-control interaction paradigm for haptic interface systems, with experimental data from two user studies. Shared control, evolved from its initial telerobotics applications, is adapted as a form of haptic assistance in that the haptic device contributes to execution of a dynamic manual target-hitting task via force commands from an automatic controller. Compared to haptic virtual environments, which merely display the physics of the virtual system, or to passive methods of haptic assistance for performance enhancement based on virtual fixtures, the shared-control approach offers a method for actively demonstrating desired motions during virtual environment interactions. The paper presents a thorough review of the literature related to haptic assistance. In addition, two experiments were conducted to independently verify the efficacy of the shared-control approach for performance enhancement and improved training effectiveness of the task. In the first experiment, shared control is found to be as effective as virtual fixtures for performance enhancement, with both methods resulting in significantly better performance in terms of time between target hits for the manual target-hitting task than sessions where subjects feel only the forces arising from the mass-spring-damper system dynamics. Since shared control is more general than virtual fixtures, this approach may be extremely beneficial for performance enhancement in virtual environments. In terms of training enhancement, shared control and virtual fixtures were no better than practice in an unassisted mode. For manual control tasks, such as the one described in this paper, shared control is beneficial for performance enhancement, but may not be viable for enhancing training effectiveness. Copyright © 2006 by ASME.

%B Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME %V 128 %P 75 - 85 %G eng %U http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA000128000001000075000001&idtype=cvips&gifs=yes %& 75 %R 10.1115/1.2168160 %> https://mahilab.rice.edu/sites/default/files/publications/52-00%20-%20JDSMC%20Shared%20control.pdf %0 Conference Proceedings %B First Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (WHC'05) %D 2005 %T Human-machine admittance and transparency adaptation in passive user interaction with a haptic interface %A McJunkin, Samuel %A Yanfang Li %A O'Malley, M.K. %K Haptic interfaces %K Human computer interaction %K Manipulators %K Virtual reality %X

This paper addresses human adaptation to changes in coupling impedance and force amplitude during passive user induced (PUI) interactions with a haptic interface. PUI interactions are characterized as event-based haptic interactions or haptic recordings that are replayed to the user. In the study, virtual environments are displayed to passive users with variable coupling stiffness and force amplitudes, and transparency bandwidth and human-machine admittance are measured. Results indicate that transparency bandwidth and the human-machine admittance do not change significantly for permutations of force amplitudes and coupling impedances, nor do they vary significantly across users. The reason for this invariance is that, during a PUI interaction, users tend approach a similar displacement profile. As a result, all users will have similar apparent admittance and transparency. The findings give sufficient justification for the use of universal compensators that improve transparency bandwidth, and that can be designed based solely on a priori transparency measurements for a typical user

%B First Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (WHC'05) %C Pisa, Italy %P 283 - 9 %8 03/2005 %G eng %U http://www2.computer.org/portal/web/csdl/doi/10.1109/WHC.2005.76 %R 10.1109/WHC.2005.76 %> https://mahilab.rice.edu/sites/default/files/publications/64-00%20-%20Human-machine%20admittance%20and%20transparency%20adaptation%20in%20passive%20user%20interaction%20with%20-%20mcjunk.pdf