17 accepted papers
The stiffness of passive lower-limb exoskeletons and orthoses governs their assistance. A common practice in the design of these systems is to assume the stiffness of the device is determined only by the intended elastic element (e.g., spring), while the structural components, human attachments, and
The mechanical impedance of the human lower-limb joints during locomotion encodes our understanding of how the neuromotor system regulates the behavior of these tasks. Impedance is also a key component of several strategies for translating this behavior to robots, powered prosthetic limbs, and peopl
Exoskeleton controllers have recently employed machine learning (ML) techniques to provide appropriate assistance throughout the terrains of the real world. One successful approach has been to learn a mapping between an exoskeleton wearer's kinematic measurements and a gait state vector that encodes
In addition to lifting up the body during gait, human legs provide stabilizing torques that can be modeled as a spring-damper mechanical impedance. While powered prosthetic leg actuators can also imitate spring-damper behaviors, the rendered impedance can be quite different from the desired impedanc
Ankle foot orthoses (AFOs) are one of the most prescribed mobility devices for individuals with walking disability from conditions like cerebral palsy (CP) and stroke. Current AFO designs offer a fixed stiffness during walking, functioning optimally at only a single speed. The primary goal of this s
Springs are essential mechanical elements that are used across a wide variety of industries and mechanisms. Common across many spring types and applications is the importance of compactness, low mass and customizability. In this paper, we present a novel rotary spring design that is lightweight, com…
Modern exoskeletons are typically developed to optimize for a single, physiological objective, the “gold standard” of which is a reduction of the wearer's metabolic rate. However, recent research suggests that these changes in metabolic rate are not yet perceivable on average. To address this gap, t…
Exoskeletons have shown great potential to enhance locomotion by augmenting the lower limb. While most research has focused on steady-state ambulatory activities, the ability to assist transient, ballistic tasks is also important for understanding the potential of exoskeletons in mobility enhancemen…
Emerging variable-stiffness ankle prostheses can modulate their stiffness to meet differing biomechanical demands. To this end, knowledge of the optimal ankle stiffness is required for each user and activity. One approach is to match the stiffness of prosthesis to the user’s preference, but t
Many exoskeletons today are primarily tested in controlled, steady-state laboratory conditions that are unrealistic representations of their real-world usage in which walking conditions (<i>e</i>.<i>g</i>., speed, slope, and stride length) change constantly. One potential solution is to detect these
Wearable robots, such as bionic prostheses and exoskeletons, have been conventionally designed with low-torque, high-speed motors and high transmission ratios; however, recently designers are increasingly implementing high-torque, low-speed motors with lower transmission ratios. These motors were po
Impressive animal locomotion capabilities are mediated by the co-evolution of the skeletal morphology and muscular properties. Legged robot performance would also likely benefit from the co-optimization of actuators and leg morphology. However, development of custom actuators for legged robots is ex…
Mobility disabilities are prominent in society with wide-ranging deficits, motivating modular, partial-assist, lower-limb exoskeletons for this heterogeneous population. This paper introduces the Modular Backdrivable Lower-limb Unloading Exoskeleton (M-BLUE), which implements high torque, low mechan
Most controllers for lower-limb robotic prostheses require individually tuned parameter sets for every combination of speed and incline that the device is designed for. Because ambulation occurs over a continuum of speeds and inclines, this design paradigm requires tuning of a potentially prohibitiv…
Wearable robots have the potential to improve the lives of countless individuals; however, challenges associated with controlling these systems must be addressed before they can reach their full potential. Modern control strategies for wearable robots are predicated on activity-specific implementati
Recently, brushless motors with especially high torque densities have been developed for applications in autonomous aerial vehicles (i.e. drones), which usually employ exterior rotortype geometries (ER-BLDC motors). These motors are promising for other applications, such as humanoids and wearable ro…
Modern passive ankle-foot prostheses do not exhibit appropriate biomechanics during walking, and are unable to adjust their mechanics for other mobility tasks, such as stair traversal or quiet standing. In this paper, we introduce a quasi-passive ankle-foot prosthesis that addresses these challenges…