Proceedings of the ... IEEE/RAS-EMBS International Conference on Biomedical Robotics and Biomechatronics. IEEE/RAS-EMBS International Conference on Biomedical Robotics and Biomechatronics最新文献

Increased effort during use of the paretic arm and hand can provoke involuntary abnormal synergy patterns and amplify stiffness effects of muscle tone for individuals after stroke, which can add difficulty for user-controlled devices to assist hand movement during functional tasks. We study how volitional effort, exerted in an attempt to open or close the hand, affects resistance to robot-assisted movement at the finger level. We perform experiments with three chronic stroke survivors to measure changes in stiffness when the user is actively exerting effort to activate ipsilateral EMG-controlled robot-assisted hand movements, compared with when the fingers are passively stretched, as well as overall effects from sustained active engagement and use. Our results suggest that active engagement of the upper extremity increases muscle tone in the finger to a much greater degree than through passive-stretch or sustained exertion over time. Potential design implications of this work suggest that developers should anticipate higher levels of finger stiffness when relying on user-driven ipsilateral control methods for assistive or rehabilitative devices for stroke.

Action observation (AO) therapy is a promising rehabilitative treatment for motor and language function in individuals recovering from neurological conditions, such as stroke. This pilot study aimed to investigate the potential of humanoid robots to support AO therapy in rehabilitation settings. The brain activity of three healthy right-handed participants was monitored with electroencephalography (EEG) while they observed eight different actions performed by two agents, a human actor and a robot, using their left and right arms. Their event-related spectral perturbations (ERSPs, changes in the spectral power of neural oscillations in response to an event or stimulus, compared to baseline) in sensorimotor regions were analyzed. The single-subject analysis showed variability in ERSP patterns among all participants, including power suppression in sensorimotor mu and beta rhythms. One participant showed stronger responses to "robot" AO conditions than to "human" conditions. Strong and positive correlations in ERSP across all conditions were observed for almost all participants and channels, implying common cognitive processes or neural networks at play in the mirror neuron system during AO. The results support the feasibility of using EEG to explore differences in neural responses to observation of robot- and human-induced actions.

The influence of haptic interaction in human-human, human-robot, and human-robot-human teams is a growing field of research. Prior investigations of robot-based haptic dyads have shown that a haptic connection to a partner during motor training may improve motor learning. These studies, however, primarily investigate healthy young adults. Stroke patients may benefit from learning with a haptic connection to a partner, but it is unclear if this connection will cause the patient to slack-reducing their effort or attention during training. We present our design for the TheraDyad, a low-cost robotic rehabilitation system to haptically connect dyads with and without impairments. We also present preliminary motor learning and user experience results for nine participants (61.7 ± 4.9 years), of whom three are post-stroke and six are healthy, learning a 1-DOF target tracking task with the TheraDyad. Our findings support the usability of TheraDyad and suggest that stroke survivors do not reduce effort when paired with a healthy partner. Furthermore, we provide preliminary evidence that interacting with a healthy partner improves motor learning for the post-stroke partner. More work is needed to generalize these results and draw clear conclusions about the use of haptic dyads for multi-user robot-based post-stroke rehabilitation.

Partial-assist ankle exoskeletons have been limited by inherent trade-offs between favorable characteristics including high torque capacity, high control bandwidth, back-drivability, compliance, and low mass. Emerging quasi-direct drive actuators have a rigid transmission with a low gear ratio, enabling inherent backdrivability and compliance with accurate torque and position control. Our existing modular, backdrivable exoskeleton system (M-BLUE) uses quasi-direct drive actuators at the hip and/or knee to deliver high assistive torques alongside low dynamic backdrive torques, enabling natural interaction with users with remnant voluntary motion. This paper extends our modular system with the design and validation of a back-drivable ankle exoskeleton module to assist both plantarflexion and dorsiflexion. The bi-directional torque capabilities enable the study of control methods and gait outcomes for able-bodied users and users with gait impairments. Benchtop tests of the actuator performance and control bandwidth indicate that the position, voltage, and current control modes can provide assistance to the ankle joint across activities of daily living (ADLs). We also implement an optimal task-agnostic energy shaping controller for an experiment with a single human subject to validate the ability of the ankle exoskeleton to provide biomimetic torque assistance across a circuit of ADLs.

Manipulating flexible and underactuated objects, such as a whip, remains a significant challenge in robotics. Remarkably, humans can skillfully manipulate such objects to achieve tasks, ranging from hitting distant targets to extinguishing a cigarette's in someone's mouth with the tip of a whip. This study explored this problem by constructing and modeling a 25-degree-of-freedom whip. Our goal was to investigate the strategies employed by humans when using a whip to strike a target. To that end, a human-inspired controller was devised that emulated two observed movement strategies: "striking only" and "preparing and striking". While the latter strategy involved a more intricate and parameter-intensive trajectory definition, our findings revealed that the more complex "preparing and striking" approach enabled the whip to reach targets at greater distances. The outcomes of this study provided first insights into preparatory movements that humans employ when manipulating objects. By directly bridging between human and robot studies, we show how insights into human movements may inform effective robot control strategies for the manipulation of underactuated objects.

Resource constraints are common in prosthetic device research, and research and development inevitably occurs simultaneously. Managing the balance between device upgrades, repairs, and ensuring reliability for participant use present a continuous challenge. This paper introduces an automated robustness testing protocol designed to assess device performance and reliability. The protocol was designed to validate software updates, identify issues, and ensure consistency across prototypes and repairs. We used this method to test new design and software iterations to an active leg system. The protocol was used to successfully identify and address potential issues before participant sessions including deviations in sensors, disconnecting wires, and software bugs. It was also used to demonstrate consistency in mechanical responses across multiple prototypes of the active leg system. Our results show that this method has the capability to identify potential issues before participant sessions, ensuring smoother research workflows and minimizing disruptions during participant use.

Strength and selective motor control are primary determinants of pathological gait in children with cerebral palsy (CP) and other neuromotor disorders. Emerging evidence suggests robotic application of task-specific resistance to functional movements may provide the opportunity to strengthen muscles and improve neuromuscular function during walking in children with CP. Such a strategy could be most beneficial to children who are more severely affected by the pathology but their ability to overcome such resistance and maintain functional ambulation remains unclear. The goal of this study was to design, validate and evaluate initial feasibility and effects of a novel exoskeleton strategy that provides interleaved assistance and resistance to knee extension during overground walking. One participant with CP (GMFCS III) was recruited and completed ten total visits, nine walking with the exoskeleton. Our results validated the controller's ability to parse the gait cycle into five discrete phases (mean accuracy 91%) and provide knee extension assistance during stance and resistance during swing. Following acclimation to the interleaved strategy, peak knee extension was significantly improved in both the left (mean 7.9 deg) and right (15.2 deg) limbs when walking with the exoskeleton. Knee extensor EMG during late swing phase increased to 2.7 (left leg) and 1.7 (right leg) times the activation level during baseline exoskeleton walking without resistance. These results indicate that this interleaved strategy warrants further investigation in a longitudinal intervention study, particularly in individuals who may be more severely affected such that they are unable to ambulate overground using an exoskeleton training strategy that only deploys targeted resistance to limb motion.

In this study we present a new approach to plan a high-dose-rate (HDR) prostate brachytherapy (BT) using active needles recently developed by our group. The active needles realize bi-directional bending inside the tissue, and thereby more compliant with the patient's anatomy compared with conventional straight needles. A computational method is presented to first generate a needle arrangement configuration based on the patient's prostate anatomy. The needle arrangement is generated to cover the prostate volume, providing accessible channels for the radiation source during a HDR BT. The needle arrangement configuration avoids healthy organs and prevents needle collision inside the body. Then a treatment plan is proposed to ensure sufficient prescribed dosage to the whole prostate gland. The method is applied to a prostate model reconstructed from an anonymized patient to show the feasibility of this method. Finally, the active needle's capability to generate the required bending is shown. We have shown that our method is able to automatically generate needle arrangement configuration using active needles, and plan for a treatment that meets the dose objectives while using fewer needles (about 20% of conventional straight needles) than the conventional HDR BT performed by straight needles.

Surgical movements have an important stylistic quality that individuals without formal surgical training can use to identify expertise. In our prior work, we sought to characterize quantitative metrics associated with surgical style and developed a near-real-time detection framework for stylistic deficiencies using a commercial haptic device. In this paper, we implement bimanual stylistic detection on the da Vinci Research Kit (dVRK) and focus on one stylistic deficiency, "Anxious", which may describe movements under stressful conditions. Our goal is to potentially correct these "Anxious" movements by exploring the effects of three different types of haptic cues (time-variant spring, damper, and spring-damper feedback) on performance during a basic surgical training task using the da Vinci Research Kit (dVRK). Eight subjects were recruited to complete peg transfer tasks using a randomized order of haptic cues and with baseline trials between each task. Overall, all cues lead to a significant improvement over baseline economy of volume and time-variant spring haptic cues lead to significant improvements in reducing the classified "Anxious" movements and also corresponded with significantly lower path length and economy of volume for the non-dominant hand. This work is the first step in evaluating our stylistic detection model on a surgical robot and could lay the groundwork for future methods to actively and adaptively reduce the negative effect of stress in the operating room.

Infants at risk for developmental delays often exhibit postures and movements that may provide a window into potential impairment for cerebral palsy and other neuromotor conditions. We developed a simple 4 DOF robot pediatric simulator to help provide insight into how infant kinematic movements may affect the center of pressure (COP), a common measure thought to be sensitive to neuromotor delay when assessed from supine infants at play. We conducted two experiments: 1) we compared changes in COP caused by limb movements to a human infant and 2) we determined if we could predict COP position due to limb movements using simulator kinematic pose retrieved from video and a sensorized mat. Our results indicate that the limb movements alone were not sufficient to mimic the COP in a human infant. In addition, we show that given a robot simulator and a simple camera, we can predict COP measured by a force sensing mat. Future directions suggest a more complex robot is needed such as one that may include trunk DOF.