@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} } @article {071210493824, title = {Design of a haptic arm exoskeleton for training and rehabilitation}, journal = {IEEE/ASME Transactions on Mechatronics}, volume = {11}, number = {3}, year = {2006}, note = {

Arm exoskeletons;Apparent inertia;Design methodology;

}, pages = {280 - 289}, abstract = {

A high-quality haptic interface is typically characterized by low apparent inertia and damping, high structural stiffness, minimal backlash, and absence of mechanical singularities in the workspace. In addition to these specifications, exoskeleton haptic interface design involves consideration of space and weight limitations, workspace requirements, and the kinematic constraints placed on the device by the human arm. These constraints impose conflicting design requirements on the engineer attempting to design an arm exoskeleton. In this paper, the authors present a detailed review of the requirements and constraints that are involved in the design of a high-quality haptic arm exoskeleton. In this context, the design of a five-degree-of-freedom haptic arm exoskeleton for training and rehabilitation in virtual environments is presented. The device is capable of providing kinesthetic feedback to the joints of the lower arm and wrist of the operator, and will be used in future work for robot-assisted rehabilitation and training. Motivation for such applications is based on findings that show robot-assisted physical therapy aids in the rehabilitation process following neurological injuries. As a training tool, the device provides a means to implement flexible, repeatable, and safe training methodologies. \© 2006 IEEE.

}, keywords = {Damping, Degrees of freedom (mechanics), Joints (anatomy), Patient rehabilitation, Robot applications, Sensory perception, Stiffness}, url = {http://dx.doi.org/10.1109/TMECH.2006.875558}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/47-IEEEASME_HapticArmExoskeleton.pdf}, author = {Abhishek Gupta and O{\textquoteright}Malley, M.K.} } @proceedings {072310640904, title = {Experimental system identification of force reflecting hand controller}, year = {2006}, note = {

Manipulator design;Environmental impedance;Sinusoidal sweep torque input;

}, pages = {9 -}, address = {Chicago, IL, United States}, abstract = {

This paper describes the combined time and frequency domain identification of the first three degrees-of-freedom (DOF) of a six degree-of-freedom force reflecting hand controller (FRHC). The FRHC is used to teleoperate Robonaut, a humanoid robotic assistant developed by NASA, via a bilateral teleoperation architecture. Three of the six DOF of the FRHC are independently identified due to the decoupled nature of the manipulator design. The frequency response for each axis is acquired by coupling a known environmental impedance to the joint axis and then applying a sinusoidal sweep torque input. Several data sets are averaged in the frequency domain to obtain an averaged frequency response. A coherence analysis is then performed and data with low coherence values are ignored for subsequent analysis and model fitting. The paper describes the use of coherence data to ensure acceptable model fits for transfer function estimation. Results of the identification experiments are presented, including implications of assumptions of decoupling and linearity. In addition, frequency and time domain validations for each axis model are performed using data sets excluded from the parameter estimation, with strong correlation. Copyright {\textcopyright} 2006 by ASME.

}, keywords = {Degrees of freedom (mechanics), Force measurement, Frequency domain analysis, Identification (control systems), Remote control, Robotics}, author = {Zumbado, Fernando and McJunkin, Samuel 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 {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 {05239144488, title = {Design of a haptic arm exoskeleton for training and rehabilitation}, volume = {73}, number = {2 PART B}, year = {2004}, note = {

Haptic arm exoskeleton;Inertia;Structural stiffness;Kinesthetic feedback;

}, pages = {1011 - 1018}, address = {Anaheim, CA, United States}, abstract = {

A high-quality haptic interface is typically characterized by low apparent inertia and damping, high structural stiffness, minimal backlash and absence of mechanical singularities in the workspace. In addition to these specifications, exoskeleton haptic interface design involves consideration of additional parameters and constraints including space and weight limitations, workspace requirements and the kinematic constraints placed on the device by the human arm. In this context, we present the design of a five degree-of-freedom haptic arm exoskeleton for training and rehabilitation in virtual environments. The design of the device, including actuator and sensor selection, is discussed. Limitations of the device that result from the above selections are also presented. The device is capable of providing kinesthetic feedback to the joints of the lower arm and wrist of the operator, and will be used in future work for robot-assisted rehabilitation and training. Copyright {\textcopyright} 2004 by ASME.

}, keywords = {Actuators, Bandwidth, Damping, Degrees of freedom (mechanics), Friction, Human computer interaction, Kinematics, Robotic arms, Robots, Sensors, Stiffness}, attachments = {https://mahilab.rice.edu/sites/default/files/publications/gupta2004asme.pdf}, author = {Abhishek Gupta and O{\textquoteright}Malley, M.K.} } @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} }