23 accepted papers
Back support devices(BSDs) have the potential to mitigate overexertion in industrial tasks and also to provide assistance to people with weak back muscle strength in daily activity. While state-of-the-art active BSDs can offer a high assistive force, they are bulky and heavy, making them uncomfortab
The feasibility of gait entrainment to periodic mechanical perturbations varies with perturbation magnitude in neurotypical individuals. Effective design of gait entrainment studies thus requires a systematic approach to personalize periodic perturbation parameters. However, current studies still re
This study presents the design and validation of a variable stiffness actuator incorporating multiple cam mechanisms. The actuator is intended for use in walking assistance, focusing on assisting individuals with diminished ankle function. This study highlights the advantages of variable stiffness a…
This study presents the design and validation of a soft sliding stiffness structure with a soft-rigid layer sliding mechanism. It aims to mitigate ankle sprains and address the progression of chronic ankle instability by providing stiffness support. The soft-rigid layer sliding mechanism of the stru
This letter describes the use of a simulation-to-real training pipeline using autoregressive neural networks (MIntNet) for coupled-human robot motion intention prediction. Using only general prior knowledge about the interaction task, a large simulation dataset was generated and used to train a mult
A gait entrainment study was conducted using a lightweight soft robotic hip exosuit (SR-HExo) that can apply perturbations at the hip joint during treadmill walking. Periodic mechanical perturbations were applied by flat fabric Pneumatic Artificial Muscle (ff-PAM) actuators starting at a subject’s p
Understanding how human ankle mechanics are modulated when walking on various ground surfaces (e.g., soft and unstable ground surfaces) would help the development of controllers of lower extremity robots (e.g., prostheses and exoskeletons) mimicking human ankle behaviors. With this goal in mind, thi
This letter presents a user-adaptive variable damping controller that enhances the overall performance of coupled human-robot systems in terms of stability, agility, user effort, and energy expenditure during physical human-robot interaction. The controller accounts for impedance properties of the h
This paper presents the design, fabrication, and preliminary results of a soft hip exosuit to assist hip flexion and extension during walking. The exosuit uses soft and compliant materials to create a wearable robot that has a low profile, low mass, and is highly flexible to freely move with the use…
An entrainment study was conducted with a novel soft robotic ankle-foot orthosis (SR-AFO) consisting of a pair of flat fabric pneumatic artificial muscles (ff-PAM). Entrainment capabilities of a lighter soft robotic orthosis were compared with heavy rigid robotic counterparts reported previously. To
This paper presents an experimental study that investigated how humans interact with viscous, damping-defined mechanical environments and quantified the lower bounds of robotic damping that they can stably interact with. Human subjects performed posture maintenance tasks for different arm postures w…
This study validates the effectiveness of a recently developed parallel-actuated shoulder exoskeleton robot for the purpose of characterizing the neuromuscular properties of the human shoulder joint. In particular, shoulder mechanical impedance was quantified, which can be represented by a 2nd order…
This letter introduces a variable impedance controller which dynamically modulates both its damping and stiffness to improve the trade-off between stability and agility in coupled human-robot systems and reduce the human user's effort. The controller applies a range of robotic damping from negative
This paper presents a soft robotic ankle-foot orthosis (SR-AFO) exosuit designed to provide support to the human ankle in the frontal plane without restricting natural motion in the sagittal plane. The SR-AFO exosuit incorporates inflatable fabric-based actuators with a hollow cylinder design which…
This paper presents an experimental study to investigate how humans interact with a robotic arm simulating primarily unstable, damping-defined, mechanical environments, and to quantify lower bounds of robotic damping that humans can stably interact with. Human subjects performed posture maintenance…
This paper presents the design of the Multi-material Actuator for Variable Stiffness (MAVS), which consists of an inflatable soft fabric actuator fixed between two layers of rigid retainer pieces. The MAVS is designed to be integrated with a soft robotic ankle-foot orthosis (SR-AFO) exosuit to aid i…
This paper presents a variable damping controller to improve the trade-off between agility and stability in physical human-robot interaction (pHRI), while reducing user effort. Variable robotic damping, defined as a dual-sided logistic function, was determined in real time throughout a range of nega…
The purpose of this work is to introduce a newly developed exoskeleton robot designed to characterize the neuromuscular properties of the shoulder, including intrinsic and reflexive mechanisms, during static posture and dynamic movement in a 3-dimensional space. Quantitative characterization of thes…
This paper presents a variable damping control strategy to improve trade-off between agility/performance and stability in the control of the ankle exoskeleton robot. Depending on the user's intent of movement, the proposed variable damping controller determines the robotic ankle damping from negativ…
The purpose of this work is to optimize the stiffness of a novel parallel-actuated robotic exoskeleton designed to offer a large workspace. This is done in an effort to help provide a solution to the issue wearable parallel actuated robots face regarding a tradeoff between stiffness and workspace. P…
This paper presents a novel multi-axis robotic platform for the characterization of two important neuromuscular properties of the human ankle: mechanical impedance and reflex responses. The platform is capable of producing highly accurate position perturbations up to an angular speed of 200°/s and e…
This paper presents quantification of multidimensional ankle stability in relation to mechanical environments having different levels of stability. This study, for the first time, explores the range of stiffness-defined haptic environments over which young healthy individuals can maintain stability…
Managing the trade-off between performance and stability is a crucial issue in physical human-robot interaction, and this has become more important than ever apace with growing needs for physically human-interactive robots in many fields, such as assistive robotics and rehabilitation robotics. In th