A5047581083- Muscle activation and electromyography studies
- Motor Control and Adaptation
- Musculoskeletal pain and rehabilitation
- Sports injuries and prevention
- Balance, Gait, and Falls Prevention
- Shoulder Injury and Treatment
- Stroke Rehabilitation and Recovery
- Sports Performance and Training
- Structural Health Monitoring Techniques
- Control Systems and Identification
- Effects of Vibration on Health
- Prosthetics and Rehabilitation Robotics
- Tactile and Sensory Interactions
- Foot and Ankle Surgery
- Shoulder and Clavicle Injuries
- Tendon Structure and Treatment
- Neuroscience and Neural Engineering
- Botulinum Toxin and Related Neurological Disorders
- Ultrasound Imaging and Elastography
- Force Microscopy Techniques and Applications
- Electrical and Bioimpedance Tomography
- Muscle Physiology and Disorders
- Fault Detection and Control Systems
- Body Composition Measurement Techniques
- Sensor Technology and Measurement Systems
Shirley Ryan AbilityLab
2012-2025
Northwestern University
2014-2025
McCormick (United States)
2019-2024
The Wallace H. Coulter Department of Biomedical Engineering
2023
Centre for Interdisciplinary Research in Rehabilitation
2016-2019
Université de Montréal
2016
McGill University
2004-2011
Controlling the interaction forces between a human and an exoskeleton is crucial for providing transparency or adjusting assistance resistance levels. However, it open problem to control of lower-limb exoskeletons designed unrestricted overground walking. For these types exoskeletons, challenging implement force/torque sensors at every contact user direct force measurement. Moreover, important compensate exoskeleton's whole-body gravitational dynamical forces, especially heavy exoskeletons....
Dynamic joint stiffness defines the dynamic relationship between position of a and torque acting about it can be separated into intrinsic reflex components. Under stationary conditions, these identified using nonlinear parallel-cascade algorithm that models stiffness-a linear response to position-and velocity-as parallel pathways. Experiments this method show both depend strongly on operating point, defined by torque, likely because some underlying behavior not modeled structure....
<title>Abstract</title> <bold>Background:</bold> Lower-limb exoskeletons are a useful tool in rehabilitation settings as they can provide customized assistance to individuals during functional exercises. These approaches typically rely on state-machine-based control with impedance controllers tailored different locomotion phases, ensuring appropriate across various activities and environments. However, these methods necessitate lengthy calibration procedures, many parameters need be...
System identification of physiological systems poses unique challenges, especially when the structure system under study is uncertain. Nonparametric techniques can be useful for identifying structure, but these typically assume stationarity and require large amounts data. Both requirements are often not easily obtained in systems. Ensemble methods time-varying nonparametric estimation have been developed to address issue stationarity, an amount data that prohibitive many experimental To this...
Behaviors we perform each day, such as manipulating an object or walking, require precise control of the interaction forces between our bodies and environment. These are generated by muscle contractions, specified nervous system, joint mechanics, determined intrinsic properties musculoskeletal system. Depending on behavioral goals, mechanics might simplify complicate movement Whether humans can exploit to neural remains unclear. Here evaluated if leveraging simplifies comparing performance...
Regulating ankle mechanics is essential for controlled interactions with the environment and rejecting unexpected disturbances. Ankle can be quantified by impedance, dynamic relationship between an imposed displacement torque generated in response. impedance sagittal plane depends strongly on triceps surae Achilles tendon, but their relative contributions remain unknown. It commonly assumed that changing muscle activation and, thereby, this ignores tendon also changes activation-induced...
Regulating the impedance of our joints is essential for effective control posture and movement. The a joint governed mainly by mechanical properties muscle-tendon units spanning it. Many studies have quantified net but not specific contributions from muscles tendons. inability to quantify both muscle tendon limits ability determine causes underlying altered movement associated with aging, neuromuscular injury, other conditions that different effects on properties. Therefore, we developed...
This study examined the sensitivity of stretch reflexes elicited in elbow muscles to background activity these same during movement and postural tasks. We found a heightened reciprocal control reflex that was not present maintenance posture. These results help explain previous discrepancies measured posture provide simple model for assessing their contributions muscle both
Joint stiffness defines the dynamic relationship between position of joint and torque acting about it. is composed two components: intrinsic reflex stiffness. Separating components difficult because they appear change together. A number approaches have been used to distinguish components, but all these are inherently off-line. We developed a novel algorithm that estimates ankle in real time. Cross-correlations position, velocity, acceleration estimate The then estimated by subtracting...
One approach to designing robotic prostheses that interact with the environment in a naturally compliant fashion is design them mechanical properties replicate functions of an intact limb. Limb and joint mechanics can be quantified using estimates impedance, measure also regulated systems feedback control. Numerous studies have impedance joints under static postural conditions. However, few during movement shown it differs drastically from obtained Specifically, component known as stiffness,...
Optimizing skill acquisition during novel motor tasks and regaining lost functions have been the interest of many researchers over past few decades. One approach shown to accelerate learning involves haptically coupling two individuals through robotic interfaces. Studies that an individual's solo performance upper-limb tracking may improve after haptically-coupled training with a partner. In this study, our goal was investigate whether these findings can be translated lower-limb tasks, more...
Accurate and swift tuning of joint impedance is crucial to perform movement interaction with our environment. Time-varying system identification enables quantification during movement. Many methods have been developed over the years, each their own mathematical approach underlying assumptions. Yet, for impedance, a systematic comparison revealing method's unique strengths weaknesses, lacking. Here, we propose quantitative framework compare these methods. The used review five time-varying...
Joint impedance is an important property of the human muscular system and plays a role in control movement posture. Previous studies showed that joint varies with position activation level surrounding muscles; however, it remains unknown how during movement. Non-parametric algorithms estimate time-varying do exist; however these require hundreds realizations same behavior. In this paper we develop non-parametric algorithm can slowly using multiple short data segments. Using simulated...