Teaching a robot manipulation skills through demonstration

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (p. 127-129).An automated software system has been developed to allow robots to learn a generalized motor skill from demonstrations given by a human operator. Data is captured using a teleoperation suit as a task is performed repeatedly on Leonardo, the Robotic Life group's anthropomorphic robot, in different parts of his workspace. Stereo vision and tactile feedback data are also captured. Joint and end effector motions are measured through time, and an improved Mean Squared Velocity [MSV] analysis is performed to segment motions into possible goal-directed streams. Further combinatorial selection of subsets of markers allows final episodic boundary selection and time alignment of tasks. The task trials are then analyzed spatially using radial basis functions [RBFs] to interpolate demonstrations to span his workspace, using the object position as the motion blending parameter. An analysis of the motions in the object coordinate space [with the origin defined at the object] and absolute world-coordinate space [with the origin defined at the base of the robot], and motion variances in both coordinate frames, leads to a measure [referred to here as objectivity] of how much any part of an action is absolutely oriented, and how much is object-based. A secondary RBF solution, using end effector paths in the object coordinate frame, provides precise end-effector positioning relative to the object. The objectivity measure is used to blend between these two solutions, using the initial RBF solution to preserve quality of motion, and the secondary end-effector objective RBF solution to increase the robot's capability to engage objects accurately and robustly.by Jeff Lieberman.S.M

Accelerated and improved motor learning and rehabilitation using kinesthetic feedback

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2006.Includes bibliographical references (p. 69-71).About 21 million people in the United States [roughly 8%] have a basic motor skill inability [13], many stemming not from atrophy, but an improper mapping from the brain to the motor system. Devices exist today to aid people in rebuilding their motor system mappings, but do so in bulky, and inconvenient ways, since many of the users have adequate muscle strength, but the inability to control it properly. Hundreds of millions of people in the world participate in the arts, most of which involve motion of some sort. Typically, to become able to properly perform/paint/dance/etc, training is necessary. We learn from visual and auditory feedback, and sometimes, from the touch of a teacher. This research aims to improve the efficacy of such training with robotic touch, to enable people to become better, faster. This research proposes an augmented sensory feedback system - a lightweight comfortable wearable device that utilizes the communication channel of direct touch on the body, to give real-time feedback to the wearer about their performance in motor skill tasks. Using vibrotactile signals to indicate joint error in a user's motion, we enable a user to wear a full-body suit that provides subtle cues for the brain, as they perform a variety of motor skill tasks.(cont.) The hope is that utilizing tactile real-time feedback will act as a dance teacher or physical therapist does: by giving muscle aid through informational touch cues, not only through force or torque. This will enable people to undergo constant therapy/training, over all joints of the body simultaneously. with higher accuracy than a therapist/teacher provides. The device will enable more rapid motor rehabilitation and postural retraining to combat repetitive strain injuries (RSIs). It will also allow allow communication between a motion expert and a student in real-time [by comparing the student's performance to an expert's]. to aid in higher level motor learning skills such as sports and dance. It will function as a tool to accelerate and deepen peoples motor learning capabilities. This thesis focuses on actuator selection and feedback mechanisms for such a suit, in a low-joint-number test, comprising elements of the upper arm. Initial tests on a 5 degree-of-freedom suit show a decrease in motion errors of roughly 21% (p = 0.015), with 15% lower steady-state error (p = 0.007) and a 7% accelerated rate of learning (p = 0.007).by Jeff Lieberman.S.M

Time to discontinuation of atypical versus typical antipsychotics in the naturalistic treatment of schizophrenia

BACKGROUND: There is an ongoing debate over whether atypical antipsychotics are more effective than typical antipsychotics in the treatment of schizophrenia. This naturalistic study compares atypical and typical antipsychotics on time to all-cause medication discontinuation, a recognized index of medication effectiveness in the treatment of schizophrenia. METHODS: We used data from a large, 3-year, observational, non-randomized, multisite study of schizophrenia, conducted in the U.S. between 7/1997 and 9/2003. Patients who were initiated on oral atypical antipsychotics (clozapine, olanzapine, risperidone, quetiapine, or ziprasidone) or oral typical antipsychotics (low, medium, or high potency) were compared on time to all-cause medication discontinuation for 1 year following initiation. Treatment group comparisons were based on treatment episodes using 3 statistical approaches (Kaplan-Meier survival analysis, Cox Proportional Hazards regression model, and propensity score-adjusted bootstrap resampling methods). To further assess the robustness of the findings, sensitivity analyses were performed, including the use of (a) only 1 medication episode for each patient, the one with which the patient was treated first, and (b) all medication episodes, including those simultaneously initiated on more than 1 antipsychotic. RESULTS: Mean time to all-cause medication discontinuation was longer on atypical (N = 1132, 256.3 days) compared to typical antipsychotics (N = 534, 197.2 days; p < .01), and longer on atypicals compared to typicals of high potency (N = 320, 187.5 days; p < .01), medium potency (N = 140, 213.5 days; p < .01), and low potency (N = 74, 208.7 days; p < .01). Among the atypicals, only clozapine, olanzapine, and risperidone had significantly longer time to all-cause medication discontinuation compared to typicals, regardless of potency level, and compared to haloperidol with prophylactic anticholinergic treatment. When compared to perphenazine, a medium-potency typical antipsychotic, only clozapine and olanzapine had a consistently and significantly longer time to all-cause medication discontinuation. Results were confirmed by sensitivity analyses. CONCLUSION: In the usual care of schizophrenia patients, time to medication discontinuation for any cause appears significantly longer for atypical than typical antipsychotics regardless of the typical antipsychotic potency level. Findings were primarily driven by clozapine and olanzapine, and to a lesser extent by risperidone. Furthermore, only clozapine and olanzapine therapy showed consistently and significantly longer treatment duration compared to perphenazine, a medium-potency typical antipsychotic

Reversing the Outcome of Synapse Elimination at Developing Neuromuscular Junctions In Vivo: Evidence for Synaptic Competition and Its Mechanism

Competition between neurons for the same synaptic sites at the developing neuromuscular junction drives synaptic rearrangements

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Teaching a Robot Manipulation Skills Through Demonstration

An automated software system has been developed to allow robots to learn a gener-alized motor skill from demonstrations given by a human operator. Data is captured using a teleoperation suit as a task is performed repeatedly on Leonardo, the Robotic Life group&apos;s anthropomorphic robot, in different parts of his workspace. Stereo vi-sion and tactile feedback data are also captured. Joint and end effector motions are measured through time, and an improved Mean Squared Velocity [MSV] analysis is performed to segment motions into possible goal-directed streams. Further combina-torial selection of subsets of markers allows final episodic boundary selection and time alignment of tasks. The task trials are then analyzed spatially using radial basis func-tions [RBFs] to interpolate demonstrations to span his workspace, using the object position as the motion blending parameter. An analysis of the motions in the object coordinate space [with the origin defined at the object] and absolute world-coordinate space [with the origin defined at the base of the robot], and motion variances in both coordinate frames, leads to a measure [referred to here as objectivity] of how much an

TIKL: development of a wearable vibrotactile feedback suit for improved human motor learning

Abstract-When a human learns a new motor skill from a teacher, they learn using multiple channels: They receive high level information aurally about the skill, visual information about how another performs the skill, and at times, tactile information, from a teacher&apos;s physical guidance of the student. This research proposes a novel approach, the application of this tactile feedback through a robotic wearable system, while a student tries to learn from a teacher. Initial tests on a 5-DOF robotic suit show a decrease in motion errors of over 20%, and an accelerated learning rate of 7%, both conservative given the system setup and statistically very significant (p ≤ 0.01). This research is intended in use of sports training, motor rehabilitation after neurological damage, dance, postural retraining for health, and many other contexts

PlayPals: tangible interfaces for remote communication and play

PlayPals are a set of wireless figurines with their electronic accessories that provide children with a playful way to communicate between remote locations. PlayPals is designed for children aged 5-8 to share multimedia experiences and virtual co-presence. We learned from our pilot study that embedding digital communication into existing play pattern enhances both remote play and communication

Taptap: a haptic wearable for asynchronous distributed touch therapy

TapTap is a wearable haptic system that allows nurturing human touch to be recorded, broadcast and played back for emotional therapy. Haptic input/output modules in a convenient modular scarf provide affectionate touch that can be personalized. We present a working prototype informed by a pilot study