@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 {06169823659, title = {Transparency extension in haptic interfaces via adaptive dynamics cancellation}, volume = {74 DSC}, number = {2 PART B}, year = {2005}, note = {

Transparency extension;Robotic manipulators;Transparency transfer function (TTF);Model cancellation techniques;

}, pages = {1581 - 1587}, address = {Orlando, FL, United States}, abstract = {

Haptic interfaces are a class of robotic manipulators that display force feedback to enhance the realism of virtual environment displays. However, these manipulators often fail to effectively replicate the real world environment due to dynamic limitations of the manipulator itself. The ratio of the simulated to transmitted environment impedance is defined as the transparency transfer function (TTF), and can be used to quantify the effectiveness of a haptic device in displaying the simulated environment. The TTF is ideally equal to one for the bandwidth of human proprioception. In this work, a method is presented that increases TTF bandwidth via cancellation of dynamics with an adaptive model. This adaptive model is based on the kinematics and dynamics of a PHANToM haptic interface with assumed joint stiffness and damping added. The Lagrangian of the PHANToM is reformulated into a regressor matrix containing the state variables multiplied by a parameter vector. A least-squares approach is used to estimate the parameter vector by assuming that errors in force output are due to the manipulator dynamics. The parameter estimate is then used in the original model to provide a feed-forward cancellation of the manipulator dynamics. Software simulation using data from passive user interactions shows that the model cancellation technique improves bandwidth up to 35 Hz versus 7 Hz without compensation. Finally, this method has a distinct advantage when compared with other compensation methodsfor haptic interactions because it does not rely on linear assumptions near a particular operating point and will adapt to capture unmodeled features. Copyright {\textcopyright} 2005 by ASME.

}, keywords = {Adaptive control systems, Computer simulation, Linear systems, Manipulators, Mathematical models, Transfer functions}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/mcjunkin2005asme.pdf}, author = {McJunkin, Samuel and Speich, John E. and O{\textquoteright}Malley, M.K.} } @proceedings {04278244649, title = {Comparison of human haptic size discrimination performance in simulated environments with varying levels of force and stiffness}, year = {2004}, note = {

Size discrimination experiments;Machine quality;Haptic devices;

}, pages = {169 - 175}, address = {Chicago, IL, United States}, abstract = {

The performance levels of human subjects in size discrimination experiments in virtual environments with varying levels of stiffness and force saturation are presented. The virtual environments are displayed with a Phantom desktop three degree-of-freedom haptic interface. Performance was measured at below maximum machine performance levels for two machine parameters: maximum endpoint force and maximum virtual surface stiffness. The tabulated scores for the size discrimination in the sub-optimal virtual environments, except for those of the lowest stiffness, 100 N/m, were found to be comparable to that in the highest-quality virtual environment. This supports previous claims that haptic interface hardware may be able to convey, for this perceptual task, sufficient perceptual information to the user with relatively low levels of machine quality in terms of these parameters, as long as certain minimum levels, 1.0 N force and 220 N/m stiffness, are met.

}, keywords = {Computer simulation, Computer software, Degrees of freedom (mechanics), Feedback, Haptic interfaces, Human engineering, Stiffness}, url = {http://dx.doi.org/10.1109/HAPTIC.2004.1287193}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/upperman2004haptics.pdf}, author = {Gina Upperman and Suzuki, Atsushi and O{\textquoteright}Malley, M.K.} } @proceedings {04278244642, title = {Cooperative manipulation between humans and teleoperated agents}, year = {2004}, note = {

Robonauts;Haptic feedback;Cooperative manipulation;

}, pages = {114 - 120}, address = {Chicago, IL, United States}, abstract = {

Robonaut is a humanoid robot designed by the Robotic Systems Technology Branch at NASA{\textquoteright}s Johnson Space Center in a collaborative effort with DARPA. This paper describes the implementation of haptic feedback into Robonaut. We conducted a cooperative manipulation task, inserting a flexible beam into an instrumented receptacle. This task was performed while both a human at the worksite and the teleoperated robot grasped the flexible beam simultaneously. Peak forces in the receptacle were consistently lower when the human operator was provided with kinesthetic force feedback in addition to other modalities of feedback such as gestures and voice commands. These findings are encouraging as the Dexterous Robotics Lab continues to implement force feedback into its teleoperator hardware architecture.

}, keywords = {Computer simulation, Feedback, Haptic interfaces, Human computer interaction, Robots, Statistical methods}, url = {http://dx.doi.org/10.1109/HAPTIC.2004.1287185}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/glassmire2004haptics.pdf}, author = {John Glassmire and O{\textquoteright}Malley, M.K. and William Bluethmann and Robert O. Ambrose} } @article {04338307919, title = {The effect of virtual surface stiffness on the haptic perception of detail}, journal = {IEEE/ASME Transactions on Mechatronics}, volume = {9}, number = {2}, year = {2004}, note = {

Virtual surface stiffness;Haptic perception;Design specifications;Haptic interface hardware;

}, pages = {448 - 454}, abstract = {

This brief presents a quantitative study of the effects of virtual surface stiffness in a simulated haptic environment on the haptic perception of detail. Specifically, the haptic perception of detail is characterized by identification, detection, and discrimination of round and square cross section ridges. Test results indicate that performance, measured as a percent correct score in the perception experiments, improves in a nonlinear fashion as the maximum level of virtual surface stiffness in the simulation increases. Further, test subjects appeared to reach a limit in their perception capabilities at maximum stiffness levels of 300 to 400 N/m, while the hardware was capable of 1000 N/m of maximum virtual surface stiffness. These results indicate that haptic interface hardware may be able to convey sufficient perceptual information to the user with relatively low levels of virtual surface stiffness. \© 2004 IEEE.

}, keywords = {Computer aided design, Computer hardware, Computer simulation, Degrees of freedom (mechanics), Manipulators, Object recognition, Sensory perception, Specifications, Stiffness, Surface properties, Virtual reality}, url = {http://dx.doi.org/10.1109/TMECH.2004.828625}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/44-09tmech02omalley-print.pdf}, author = {O{\textquoteright}Malley, M.K. and Michael Goldfarb} } @proceedings {04448428417, title = {Virtual labs in the engineering curriculum}, year = {2004}, note = {

Engineering curriculum;Real-time parametric changes;Graphical interfaces;Virtual labs;

}, pages = {15293 - 15304}, address = {Salt Lake City, UT, United States}, abstract = {

Computer simulations have been developed for use as student exercises to illustrate concepts required for various engineering courses. These simulations or Virtual Labs are highly graphical and interactive to help undergraduate students understand basic concepts by graphically solving problems and by visualization of real-time parametric changes. These Virtual Labs (or VL{\textquoteright}s) can be used productively in conjunction with existing laboratory experiments as pre-lab exercises, but the more important benefit is realized in cases of concepts that have no experimental support and in courses that traditionally do not have an associated laboratory course. These VL{\textquoteright}s are generated in the software package Lab VIEW, which offers graphical interfaces for the student and can be formatted as standalone files, which the students can download and access at their convenience, without the need for Lab VIEW software. Currently five VL{\textquoteright}s have been generated and several have been evaluated by students in appropriate classes.

}, keywords = {Computer programming languages, Computer simulation, Curricula, Data reduction, Graphic methods, Students, Visualization}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/mcstravick2004asee.pdf}, author = {David M. McStravick and O{\textquoteright}Malley, M.K.} } @article {02427145860, title = {The effect of force saturation on the haptic perception of detail}, journal = {IEEE/ASME Transactions on Mechatronics}, volume = {7}, number = {3}, year = {2002}, note = {Force saturation effect;Haptic perception;Force feedback;}, pages = {280 - 288}, abstract = {

This paper presents a quantitative study of the effects of maximum capable force magnitude of a haptic interface on the haptic perception of detail. Specifically, the haptic perception of detail is characterized by identification, detection, and discrimination of round and square cross-section ridges, in addition to corner detection tests. Test results indicate that performance, measured as a percent correct score in the perception experiments, improves in a nonlinear fashion as the maximum allowable level of force in the simulation increases. Further, all test subjects appeared to reach a limit in their perception capabilities at maximum-force output levels of 3-4 N, while the hardware was capable of 10 N of maximum continuous force output. These results indicate that haptic interface hardware may be able to convey sufficient perceptual information to the user with relatively low levels of force feedback. The data is compiled to aid those who wish to design a stylus-type haptic interface to meet certain requirements for the display of physical detail within a haptic simulation.

}, keywords = {Computer control systems, Computer simulation, Feedback control, Haptic interfaces, Identification (control systems), Nonlinear control systems, Virtual reality}, url = {http://dx.doi.org/10.1109/TMECH.2002.802725}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/omalley2002ieee.pdf}, author = {O{\textquoteright}Malley, M.K. and Michael Goldfarb} } @proceedings {01416683554, title = {Force saturation, system bandwidth, information transfer, and surface quality in haptic interfaces}, volume = {2}, year = {2001}, note = {

Information transfer;

}, pages = {1382 - 1387}, address = {Seoul}, abstract = {

This paper presents a two-part study of the effects of maximum endpoint force and system bandwidth on haptic perception. First, size identification experiments were performed to determine the effects of system quality, in terms of these two system parameters, on the ability of a human to identify square cross-section ridges by size in a simulated environment. Then, discrimination experiments were performed to determine relationships between haptic interface machine parameters and simulation quality in terms of perceived surface hardness. Results indicate that haptic interface hardware may be able to convey sufficient perceptual information to the user with relatively low levels of force feedback and system bandwidth, yet subjects can perceive improvements in simulated surface quality as levels are further increased.

}, keywords = {Bandwidth, Computer simulation, Computer software, Feedback, Hardness, Manipulators}, url = {http://dx.doi.org/10.1109/ROBOT.2001.932803}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/omalley2001ieee.pdf}, author = {Marcia Kilchenman and Michael Goldfarb} }