@proceedings {526, title = {Effects of Force and Displacement Cues while Adapting in a Rhythmic Motor Task}, year = {2009}, pages = {32-33}, address = {Seattle, WA}, abstract = {

This paper explores the effects of magnitude and phase cues on human motor adaptation. Participants were asked to excite virtual second-order systems at their resonance frequencies via a two-degree of freedom haptic interface, with visual and visual plus haptic feedback conditions. Their motor adaptations were studied through catch trials. The results indicate that, i) humans adapt to a nominal virtual system resonant frequency, ii) humans shift to higher and lower natural frequencies during catch trials regardless of feedback modality and force cues, iii) humans can detect changes in natural frequency when gain, magnitude, and phase cues are manipulated independently, and iv) humans are able to detect changes in natural frequency when the feedback (visual or visual plus haptic) is delayed such that the phase shift between the nominal system and catch trial system is zero.

}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/israr2009robotics.pdf}, author = {Ali Israr and Hakan Kapson and Volkan Patoglu and O{\textquoteright}Malley, M.K.} } @proceedings {107, title = {Effects of Magnitude and Phase Cues on Human Motor Adaptation}, year = {2009}, month = {03/2009}, pages = {344-349}, publisher = {IEEE}, address = {Salt Lake city, Utah}, abstract = {

Recent findings have shown that humans can adapt their internal control model to account for the changing dynamics of systems they manipulate. In this paper, we explore the effects of magnitude and phase cues on human motor adaptation. In our experiments, participants excite virtual second-order systems at resonance via a two-degree of freedom haptic interface, with visual and visual plus haptic feedback conditions. Then, we change the virtual system parameters and observe the resulting motor adaptation in catch trials. Through four experimental conditions we demonstrate the effects of magnitude and phase cues on human motor adaptation. First, we show that humans adapt to a nominal virtual system resonant frequency. Second, humans shift to higher and lower natural frequencies during catch trials regardless of feedback modality and force cues. Third, participants can detect changes in natural frequency when gain, magnitude, and phase cues are manipulated independently. Fourth, participants are able to detect changes in natural frequency when the feedback (visual or visual plus haptic) is delayed such that the phase shift between the nominal system and catch trial system is zero. The persistent ability of participants to perform system identification of the dynamic systems which they control, regardless of the cue that is conveyed, demonstrates the human{\textquoteright}s versatility with regard to manual control situations. We intend to further investigate human motor adaptation and the time for adaptation in order to improve the efficacy of shared control methodologies for training and rehabilitation in haptic virtual environments.

}, keywords = {catch trials, internal models, motor adaptation, Rhythmic motion}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/107-0156.pdf}, author = {Ali Israr and Hakan Kapson and Volkan Patoglu and O{\textquoteright}Malley, M.K.} } @article {103, title = {Negative Efficacy of Fixed Gain Error Reducing Shared Control for Training in Virtual Environments}, journal = {ACM Transactions on Applied Perception}, volume = {6}, number = {1}, year = {2009}, month = {01/2009}, abstract = {

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.

}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/103-Li-Patoglu-O\%27Malley_TAP_6\%281\%29_2009FINAL.pdf}, author = {Yanfang Li and Volkan Patoglu and O{\textquoteright}Malley, M.K.} } @article {102, title = {Passive and Active Discrimination of Natural Frequency of Virtual Dynamic System}, journal = {IEEE Transactions on Haptics}, volume = {2}, number = {1}, year = {2009}, month = {02/2009}, pages = {40-51}, doi = {10.1109/TOH.2008.21}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/102-Israr-Li-Patoglu-O\%27Malley_IEEEToH_2\%281\%29_2009FINAL.pdf}, author = {Ali Israr and Yanfang Li and Volkan Patoglu and O{\textquoteright}Malley, M.K.} } @proceedings {109, title = {Progressive shared control for training in virtual environments}, year = {2009}, month = {03/2009}, pages = {332-337}, publisher = {IEEE}, address = {Salt Lake City, UT, USA}, keywords = {Haptic interface, performance, shared control, training}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/109-LiPSC-WHC.pdf}, author = {Yanfang Li and Joel C. Huegel and Volkan Patoglu and O{\textquoteright}Malley, M.K.} } @article {080611080561, title = {Design, control and performance of RiceWrist: A force feedback wrist exoskeleton for rehabilitation and training}, journal = {International Journal of Robotics Research}, volume = {27}, number = {2}, year = {2008}, note = {

Feedback wrist exoskeleton;Neurological injuries;

}, pages = {233 - 251}, abstract = {

This paper presents the design, control and performance of a high fidelity four degree-of-freedom wrist exoskeleton robot, RiceWrist, for training and rehabilitation. The RiceWrist is intended to provide kinesthetic feedback during the training of motor skills or rehabilitation of reaching movements. Motivation for such applications is based on findings that show robot-assisted physical therapy aids in the rehabilitation process following neurological injuries. The exoskeleton device accommodates forearm supination and pronation, wrist flexion and extension and radial and ulnar deviation in a compact parallel mechanism design with low friction, zero backlash and high stiffness. As compared to other exoskeleton devices, the RiceWrist allows easy measurement of human joint angles and independent kinesthetic feedback to individual human joints. In this paper, joint-space as well as task-space position controllers and an impedance-based force controller for the device are presented. The kinematic performance of the device is characterized in terms of its workspace, singularities, manipulability, backlash and backdrivability. The dynamic performance of RiceWrist is characterized in terms of motor torque output, joint friction, step responses, behavior under closed loop set-point and trajectory tracking control and display of virtual walls. The device is singularity-free, encompasses most of the natural workspace of the human joints and exhibits low friction, zero-backlash and high manipulability, which are kinematic properties that characterize a high-quality impedance display device. In addition, the device displays fast, accurate response under position control that matches human actuation bandwidth and the capability to display sufficiently hard contact with little coupling between controlled degrees-of-freedom.

}, keywords = {Control systems, Degrees of freedom (mechanics), Feedback, Neurology, Physical therapy, Systems analysis}, url = {http://dx.doi.org/10.1177/0278364907084261}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/48-IJRR-Feb-2008-small.pdf}, author = {Abhishek Gupta and O{\textquoteright}Malley, M.K. and Volkan Patoglu and Burgar, Charles} } @proceedings {9872945, title = {Passive and active kinesthetic perception just-noticeable-difference for natural frequency of virtual dynamic systems}, year = {2008}, note = {

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;

}, month = {03/2008}, pages = {25 - 31}, publisher = {IEEE}, address = {Reno, NE, USA}, abstract = {

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.

}, keywords = {Haptic interfaces, visual perception}, issn = {978-1-4244-2005-6}, doi = {10.1109/HAPTICS.2008.4479908}, url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4479908}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/58-HapticSymposium2008_Li.pdf}, author = {Yanfang Li and Ali Israr and Volkan Patoglu and O{\textquoteright}Malley, M.K.} } @proceedings {082211289622, title = {Disturbance observer based closed loop force control for haptic feedback}, volume = {9 PART B}, year = {2007}, note = {

Disturbance observer;Haptic feedback;Pseudostatic interactions;

}, pages = {1343 - 1349}, address = {Seattle, WA, United States}, abstract = {

Most commonly used impedance-type haptic interfaces employ open-loop force control under the assumption of pseudostatic interactions. Advanced force control in such interfaces can increase simulation fidelity through improvement of the transparency of the device, and can further improve robustness. However, closed loop force-feedback is limited both due to the bandwidth limitations of force sensing and the associated cost of force sensors required for its implementation. In this paper, we propose the use of a nonlinear disturbance observer for estimation of contact forces during haptic interactions. This approach circumvents the traditional drawbacks of force sensing while exhibiting the advantages of closed-loop force control in haptic devices. The feedback of contact force information further enables implementation of advanced robot force control techniques such as robust hybrid impedance and admittance control. Simulation and experimental results, utilizing a PHANToM Premium 1.0A haptic interface, are presented to demonstrate the efficacy of the proposed approach. Copyright {\textcopyright} 2007 by ASME.

}, keywords = {Computer simulation, Force control, Haptic interfaces, Robotics, Robustness (control systems)}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/50-gupta-imece07.pdf}, author = {Abhishek Gupta and O{\textquoteright}Malley, M.K. and Volkan Patoglu} } @proceedings {073510787453, title = {Towards just noticeable differences for natural frequency of manually excited virtual dynamic systems}, year = {2007}, note = {

Graphical displays;Virtual mass spring systems;Dynamic properties;

}, month = {03/2007}, pages = {569 - 570}, publisher = {IEEE}, address = {Tsukuba, Japan}, abstract = {

This paper explores the experiment design to determine a human{\textquoteright}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. {\textcopyright} 2007 IEEE.

}, keywords = {Display devices, Dynamical systems, Natural frequencies}, doi = {10.1109/WHC.2007.118}, url = {http://dx.doi.org/10.1109/WHC.2007.118}, attachments = {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}, author = {Yanfang Li and Volkan Patoglu and Huang, Deborah and O{\textquoteright}Malley, M.K.} } @proceedings {072310640980, title = {The RiceWrist: A distal upper extremity rehabilitation robot for stroke therapy}, year = {2006}, note = {

Mirror Image Movement Enabler (MIME) system;Rehabilitation robot;Robotic therapy;

}, month = {11/2006}, pages = {10 -}, publisher = {ASME}, address = {Chicago, IL, United States}, abstract = {

This paper presents the design and kinematics of a four degree-of-freedom upper extremity rehabilitation robot for stroke therapy, to be used in conjunction with the Mirror Image Movement Enabler (MIME) system. The RiceWrist is intended to provide robotic therapy via force-feedback during range-of-motion tasks. The exoskeleton device accommodates forearm supination and pronation, wrist flexion and extension, and radial and ulnar deviation in a compact design with low friction and backlash. Joint range of motion and torque output of the electricmotor driven device is matched to human capabilities. The paper describes the design of the device, along with three control modes that allow for various methods of interaction between the patient and the robotic device. Passive, triggered, and active-constrained modes, such as those developed for MIME, allow for therapist control of therapy protocols based on patient capability and progress. Also presented is the graphical user interface for therapist control of the interactions modes of the RiceWrist, basic experimental protocol, and preliminary experimental results. Copyright {\textcopyright} 2006 by ASME.

}, keywords = {Degrees of freedom (mechanics), Graphical user interfaces, Human rehabilitation equipment, Patient treatment}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/46-00\%20-\%20IMECE2006-16103-O\%27Malley.pdf}, author = {O{\textquoteright}Malley, M.K. and Alan Sledd and Abhishek Gupta and Volkan Patoglu and Joel C. Huegel and Burgar, Charles} } @proceedings {li_shared_2006, title = {Shared Control for Training in Virtual Environments: Learning Through Demonstration?}, year = {2006}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/73-00\%20-\%20Li_Patoglu_OMalley_Eurohaptics06.pdf}, author = {Yanfang Li and Volkan Patoglu and O{\textquoteright}Malley, M.K.} } @proceedings {072310640927, title = {Vision based force sensing for nanorobotic manipulation}, year = {2006}, note = {

Nanomanipulation;Nanoassembly;

}, pages = {10 -}, address = {Chicago, IL, United States}, abstract = {

Over the last decade, considerable interest has been generated in building and manipulating nanoscale structures. Applications of nanomanipulation include study of nanoparticles, molecules, DNA and viruses, and bottom-up nanoassembly. We propose a Nanomanipulation System using the Zyvex S100 nanomanipulator, -which operates within a scanning electron microscope (SEM), as its primary component. The primary advantage of the S100 setup over standard scanning probe microscopy based nanomanipulators is the ability to see the object during manipulation. Relying on visual feedback alone to control the nanomanipulator is not preferable due to perceptual limitations of depth and contact within the SEM. To improve operator performance over visual feedback alone, an impedance-controlled bilateral teleoperation setup is envisioned. Lack of on-board force sensors on the S100 system is the primary hindrance in the realization of the proposed architecture. In this paper, we present a computer vision based force sensing scheme. The advantages of this sensing strategy include its low cost and lack of requirement of hardware modifications). Force sensing is implemented using an atomic force microscopy (AFM) probe attached to the S100 end-effector. Deformation of the cantilever probe is monitored using a Hough transform based algorithm. These deformations are mapped to corresponding end-effector forces following the Euler-Bernoulli beam mechanics model. The forces thus sensed can be used to provide force-feedback to the operator through a master manipulator. Copyright {\textcopyright} 2006 by ASME.

}, keywords = {Atomic force microscopy, Force measurement, Manipulators, Nanoparticles, Nanotechnology, Scanning electron microscopy}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/49-IMECE2006-15111-Gupta-small.pdf}, author = {Abhishek Gupta and Volkan Patoglu and O{\textquoteright}Malley, M.K.} }