TY - Generic T1 - Passive and active kinesthetic perception just-noticeable-difference for natural frequency of virtual dynamic systems T2 - 16th Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (HAPTICS) Y1 - 2008 A1 - Yanfang Li A1 - Ali Israr A1 - Volkan Patoglu A1 - O'Malley, M.K. KW - Haptic interfaces KW - visual perception AB -

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.

JF - 16th Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (HAPTICS) PB - IEEE CY - Reno, NE, USA UR - http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4479908 N1 -

active kinesthetic perception;passive kinesthetic perception;just-noticeable-difference;virtual second order dynamic systems;degree-of-freedom haptic device;haptic sensory feedback;virtual resonance task;visual feedback;

ER - TY - JOUR T1 - Shared control in haptic systems for performance enhancement and training JF - Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME Y1 - 2006 A1 - O'Malley, M.K. A1 - Abhishek Gupta A1 - Gen, Matthew A1 - Yanfang Li KW - Control equipment KW - Damping KW - Data reduction KW - Haptic interfaces KW - Robotics KW - Robots AB -

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.

VL - 128 UR - http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA000128000001000075000001&idtype=cvips&gifs=yes N1 -

Virtual environments;Mass-spring-damper;System dynamics;Shared control;

ER - TY - Generic T1 - Human-machine admittance and transparency adaptation in passive user interaction with a haptic interface T2 - First Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (WHC'05) Y1 - 2005 A1 - McJunkin, Samuel A1 - Yanfang Li A1 - O'Malley, M.K. KW - Haptic interfaces KW - Human computer interaction KW - Manipulators KW - Virtual reality AB -

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

JF - First Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (WHC'05) CY - Pisa, Italy UR - http://www2.computer.org/portal/web/csdl/doi/10.1109/WHC.2005.76 N1 -

human-machine admittance;transparency adaptation;passive user interaction;haptic interface;force amplitude;passive user induced interactions;event-based haptic interactions;virtual environments;force amplitudes;transparency bandwidth;

ER -