Download or read book Simulating Exoskeletons to Assist Walking written by Nicholas August Bianco and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wearable robotic exoskeletons provide a promising opportunity to improve human mobility. Recent advances in assistive technology have produced reductions in energy cost of walking, but exoskeleton design can often be a time-consuming and unintuitive process. Musculoskeletal simulation is a promising approach for speeding device design by revealing how exoskeleton assistance affects muscle behavior and alters walking motions. However, few studies have yet to effectively utilize simulations for device design, and simulation pipelines are often difficult to recreate and share. This dissertation work includes three projects aimed at developing better simulation tools and using them to design exoskeleton assistance. First, my labmate Chris Dembia and I created OpenSim Moco, a flexible software package that makes it easy to create simulations for biomechanics research using optimal control. Second, I used simulations to show that exoskeletons that assist multiple joints can effectively reduce the metabolic cost of walking using a simplified control strategy. Finally, I used simulations to reveal how exoskeleton torques affect the motion of the center of mass during walking. This work can be used by designers to make informed decisions when developing exoskeleton devices to reduce metabolic cost or improve walking stability. The simulations and software I created are freely available for other researchers to build upon and to accelerate future work.

Download or read book Modelling and Simulation of Ideal and Torque Limited Devices to Assist Elderly Walking written by Tanaya Khanna and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Interest in wearable exoskeletons is increasing as the demand increases for assistive technologies that meet the needs of the elderly population. Decreased mobility and loss of independence are major concerns as the global trend of increasing mean population continues. Past research has focused on walking assistance exoskeletons to maintain, restore, and enhance mobility. However, in the current state of the art, little is understood about how to best assist elderly individuals specifically. The results from studies of younger adults may not apply because gait patterns of elderly individuals often differ from those of the younger population. This thesis investigates the effect of ideal and torque-limited assistance on metabolic energy consumption when assistance is applied at the ankle, knee, and hip joints of elderly individuals during overground gait using the OpenSim software. The simulated ideal devices have no mass and can generate unlimited torque, representing a best-case scenario where the maximum amount of metabolic energy is saved given the observed kinematics. This simulation strategy provides an approximation of the upper limit for assistive devices that aim to reduce metabolic cost. The simulations with torque limits were generated to investigate the effect of this practical limitation. This study focuses on reducing metabolic cost as fatigue during walking is a fundamental concern in the elderly population. Simulations of 10 elderly participants walking at a self-selected, comfortable speed were generated using the Computed Muscle Control Tool in OpenSim. Ideal and torque-limited devices were added bilaterally at the ankle, knee, and hip joints of the 10 corresponding musculoskeletal models. The device torque profiles and changes in the activity and metabolic power consumed by the muscles were computed. The results of this study suggest that providing hip flexion/extension assistance to elderly individuals may result in substantially greater metabolic savings compared to assistance provided at the knee or ankle. When compared to the unassisted simulations, the use of an ideal hip flexion/extension device resulted in a 24% average reduction in metabolic cost, with a loss in effectiveness of only 2 percentage points when the maximum torque was limited to 50% of the peak ideal torque; ideal hip abduction/adduction, knee flexion/extension, and ankle plantarflexion/dorsiflexion devices saved 15%, 20%, and 12%, respectively, on average. Computational studies of assistive devices can provide valuable insights for engineers who are developing walking assist exoskeletons for elderly individuals.

Download or read book Coordinated energy efficient walking assistance for paraplegic patients by using the exoskeleton walker system written by Chen Yang and published by OAE Publishing Inc.. This book was released on 2024-03-19 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Overground walking can be achieved for patients with gait impairments by using the lower limb exoskeleton robots. Since it is a challenge to keep balance for patients with insufficient upper body strength, a robotic walker is necessary to assist with the walking balance. However, since the walking pattern varies over time, controlling the robotic walker to follow the walking of the human-exoskeleton system in coordination is a critical issue. Inappropriate control strategy leads to the unnecessary energy cost of the human-exoskeleton-walker (HEW) system and also results in the bad coordination between the human-exoskeleton system and the robotic walker. In this paper, we proposed a Coordinated Energy-Efficient Control (CEEC) approach for the HEW system, which is based on the extremum seeking control algorithm and the coordinated motion planning strategy. First, the extremum seeking control algorithm is used to find the optimal supporting force of the support joint in real time to maximize the energy efficiency of the human-exoskeleton system. Second, the appropriate reference joint angles for wheels of the robotic walker can be generated by the coordinated motion planning strategy, causing the good coordination between the human-exoskeleton system and the robotic walker. The proposed approach has been tested on the HEW simulation model, and the experimental results indicate that the coordinated energy-efficient walking can be achieved with the proposed approach, which is increased by 60.16% compared to the conventional passive robotic walker.

Download or read book Simulating Assistive Technology written by Christopher L. Dembia and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: From getting to work to strolling through the park, our mobility is an essential part of life. Losing one's mobility can be devastating. Scientists are on the verge of enhancing mobility for many movement disorders via exoskeletons. However, designing effective exoskeletons is challenging because of their tight coupling with the complex human body. Computer simulations of exoskeletons can reduce the duration of lengthy human experiments and reveal the effect of an exoskeleton on muscle coordination. A promising application for exoskeletons is reducing the burden of carrying heavy loads on the torso, which is a requirement of many occupations. To guide the design of such exoskeletons, my lab performed an experiment with seven male subjects walking while carrying 88 pounds on their torso. I used these data to simulate the effect of seven hypothetical idealized devices, each providing unrestricted torque at one joint in one direction (hip abduction, hip flexion, hip extension, knee flexion, knee extension, ankle plantarflexion, or ankle dorsiflexion). My simulations predicted that a device assisting with hip abduction would be most efficient at reducing the energy required to walk while carrying heavy loads. I found that many of our devices affected muscles that were not directly assisted. This result supported the notion that exoskeletons can have complex effects that are difficult to discover via experiments, or via simulations that do not include muscles. Although my simulations yielded valuable insights, I discovered that the method I employed limited the accuracy of my predictions. The method, named Computed Muscle Control, can optimize device torques and predict changes in muscle coordination but cannot predict changes to the walking motion itself. Musculoskeletal simulation tools usually model the nervous system via objectives we believe the brain minimizes. Even though individuals might employ different objectives for different motions, the nervous system objective that Computed Muscle Control employs cannot be modified. Lastly, Computed Muscle Control cannot optimize the values of constant model parameters, such as the stiffness of an assistive device. To address the limitations of Computed Muscle Control and related simulation tools, I created a flexible framework for optimizing the motion and control of musculoskeletal models. This framework, named Moco, employs the direct collocation method, which has become a popular approach for solving related problems within and beyond the field of biomechanics. Compared to other simulation tools, Moco provides an unprecedented amount of flexibility. Researchers can choose a nervous system objective from an existing library of modules. Moco is the first musculoskeletal direct collocation tool to handle kinematic constraints, which are common in musculoskeletal models. In collaboration with a labmate, I used Moco to design a passive device to assist with a squat-to-stand motion. We predicted the stiffness of the device and a new squat-to-stand motion without relying on motion data; such predictions were challenging to conduct with previous simulation tools. Moco will accelerate the use of simulations to predict the effect of exoskeletons, orthopedic surgeries, artificial joints, and other interventions that restore and enhance mobility.

Download or read book Predictive Modeling of Human Behavior During Exoskeleton Assisted Walking written by Claire Rodman and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bipedal locomotion in humans is a complex behavior, requiring impressive coordination of the neuromuscular system. There are many hypothesized motor control objectives describing how humans might optimally govern these coordinated efforts, including minimization of energetic expenditure. However, evidence suggests that the underlying objectives are more complicated than pure energy minimization. Further, these objectives have not been thoroughly investigated during more complicated walking tasks. The mechanics of speed-varying walking and exoskeleton assisted walking, for example, are not fully understood, which makes testing different possible walking objectives difficult. This work explored the physical behavior and underlying objectives of exoskeleton-assisted and unassisted walking. The spatiotemporal behavior during walking speed transitions was investigated experimentally. The findings indicate that the magnitude of the change in speeds affects how humans execute transitions, and that different people may preferentially utilize strategies to complete the task. To explore underlying walking objectives, a computational model was developed. Specifically, a moderately complex Hybrid Zero Dynamics based model with nonuniform foot shape and muscle-tendon dynamics at the ankle was developed. Equations of motion were derived and model validation simulations demonstrated that this model is capable of producing simulated gaits that match human walking for three different nonuniform foot shape parameterizations. Finally, three candidate walking objectives were tested for unassisted and exoskeleton-assisted walking. This was done using optimization, generating simulated gait by minimizing representative objective functions. The findings indicated that humans may minimize muscle activation during walking, however additional work is still necessary to determine how this goal is balanced with other objectives. Additional simulations were executed to identify sources of error between simulated and experimental gait in the model, providing insight into the limitations and possibilities for future work.

Download or read book Electromechanics and Robotics written by Andrey Ronzhin and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book features selected papers presented at the 16th International Conference on Electromechanics and Robotics 'Zavalishin's Readings' - ER(ZR) 2021, held in St. Petersburg, Russia, on April 14-17, 2021. The contributions, written by professionals, researchers and students, cover topics in the field of automatic control systems, electromechanics, electric power engineering and electrical engineering, mechatronics, robotics, automation and vibration technologies. The Zavalishin's Readings conference was established as a tribute to the memory of Dmitry Aleksandrovich Zavalishin (1900-1968) - a Russian scientist, corresponding member of the USSR Academy of Sciences, and founder of the school of valve energy converters based on electric machines and valve converters energy. The first conference was organized by the Institute of Innovative Technologies in Electromechanics and Robotics at the Saint Petersburg State University of Aerospace Instrumentation in 2006. The 2021 conference was held with XV International Conference "Vibration-2021. Vibration technologies, mechatronics and controlled machines" and VI International Conference "Electric drive, electrical technology and electrical equipment of enterprises", and was organized by St. Petersburg State University of Aerospace Instrumentation (SUAI), St. Petersburg Federal Research Center of the Russian Academy of Sciences (SPC RAS), Southwest State University (SWSU) and Ufa State Oil Technical University (USPTU).

Download or read book Simulating Ideal Assistive Devices to Reduce the Metabolic Cost of Walking In the Elderly written by Bethany Cseke and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As the population ages, decreased mobility and loss of independence becomes a concern for many elderly individuals. Walking assist exoskeletons offer a solution for restoring, enhancing, and maintaining mobility. However, as this technology is a growing area of study pertaining to the elderly population, there is not currently a unified standard as to the optimal strategy for assisting elderly gait. The gait patterns of elderly individuals differ from that of the younger population primarily in the ankle and hip joints. This study used musculoskeletal simulations to investigate how hypothetical ankle and hip actuators affected the metabolic cost of elderly participants during gait. Using OpenSim as a modelling tool, simulations were generated of 10 elderly participants walking at a self-selected comfortable speed. Ideal flexion and extension assistive devices were then added to the ankle and hip joints of the musculoskeletal models to simulate the subsequent metabolic savings. The resulting simulations suggest that providing hip assistance to elderly participants results in significantly greater metabolic savings compared to ankle assistance. Compared to the unassisted scenario, the use of an ideal hip actuator resulted in 25.5 ± 7% metabolic savings, whereas use of an ideal ankle actuator resulted in 14.2 ± 2% metabolic savings. Our results can help researchers determine which joint to target when developing WAE for elderly users in the future.

Download or read book Development and Design of Lower Extremity Exoskeletons for Paraplegics written by and published by . This book was released on 2019 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Paraplegics are a type of Spinal Cord Injury (SCI) disabled persons who need walking assistance for day-to-day mobility. Reciprocating Gait Orthosis (RGO) and Exoskeletons are widely used walking systems to support lower extremities for successful walking. Stability has been a major concern while designing such walking support systems. This research is an attempt to design an Exoskeleton with necessary walking stability based on humanoid bipedal robot. A parallel-serial chain, 25 axes of rotation, legs-only Exoskeleton named "Lower Extremity Exoskeleton Robot (LEE Robot)" was designed, modeled and simulated for walking stability using posture adjustment and the law of balance techniques. The actuator torque requirements were calculated and controlled by implementing Proportional Derivative (PD) controllers for posture adjustment and walking balance. The most widely used Zero Moment Point (ZMP) technique was implemented in the simulation to test the Exoskeleton walking to be in the stability zone. The LEE Robot is expected to provide hands free walking to the paraplegics. Therefore, an important feature of fall protection was implemented and tested with a conceptual framework which included fall detection, fall avoidance and fall protection. The fall protection was achieved by calculating the coutner initial velocity of the swing foot end-effector and applying it as an input to the differential motion planning. Finally, the LEE Robot was analyzed for its structural strength using Finite Element Analysis (FEA) to assess the feasibility of realizing it as a useable device.

Download or read book Simplified Assistance at the Center of Mass During Human Locomotion written by Prokopios Antonellis (author.) and published by . This book was released on 2020 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of exoskeletons has undergone an evolution from complex full-body exoskeletons that did not (yet) produce the expected results towards simpler single-joint exoskeletons that can improve the mobility of people. While full-body and single-joint exoskeletons certainly have appropriate applications, we need to get a better understanding of the distal and proximal assistive mechanisms and provide insights that are currently lacking on how to assist walking in an even simpler way than single-joint exoskeletons. This dissertation details an iterative approach toward the development of simplified and efficient assistance strategies for improving human locomotion. We first conducted an experiment to observe the human response to proximal and distal perturbations by altering the treadmill grade and footwear inclination. The results indicate that the metabolic rate is predominantly sensitive to changes in the center of mass (COM) mechanics and further motivate the development of devices that can assist walking at the level of the COM. We then developed a robotic tether system that allows applying desired cyclic force profiles as a function of step time to provide whole-body assistance during walking. By leveraging the system capabilities, we performed an experiment and simple pendulum simulation to investigate the effects of timing and magnitude for non-constant force profiles at the COM. Through these experiments and the simulation, we found that assistance at the COM during the double stance phase can efficiently reduce the metabolic rate of walking half. Surprisingly, assisting propulsion did not maximize the reduction in metabolic rate, and our pendulum model revealed that the reduction in metabolic rate can instead be explained by the assistance of COM acceleration at the beginning of the step. Ultimately, our long term goal is to develop similar strategies to populations with gait disabilities, but as a primary step, we investigated the biomechanical mechanisms to assist lower limb joints using timed forward forces at the COM. To that end, we assessed the underlying mechanisms of muscle and joint parameters that explain the effects of timing and magnitude of horizontal forces at the COM on metabolic rate. The results show that the metabolically optimal timing assisted the ankle muscles that are responsible for push-off, and the knee and hip muscles that are responsible for collision. Based on these findings, it seems possible to assist different joints by different amounts by varying the timing of forces at the COM. This could be useful in clinical populations for providing ‘targeted’ joint-specific assistance without having to switch between different exoskeletons. We expect our experimental findings to provide knowledge on optimal force profiles that could be used for treadmill exercise therapy, motorized ‘rollator’-style assistive devices for walking, and even it could even inspire new strategies for combined actions of the ankle, knee, and hip of full-body exoskeletons. Timed forces at the COM could be used to assist patients with impaired gait and facilitate proactive user participation that has been identified as a critical factor in improving locomotor outcomes for rehabilitation robotics.

Download or read book Control Strategies for Robotic Exoskeletons to Assist Post Stroke Hemiparetic Gait written by Julio Salvador Lora Millán and published by Springer Nature. This book was released on with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Leg Exoskeleton Simulator for Design Sensing and Control Development written by Jiun-Yih Kuan and published by . This book was released on 2018 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: Leg exoskeletons have been developed in an effort to augment human locomotion for over a century. However, only two portable leg exoskeletal devices have shown a significant decrease in walking metabolism [35, 11], not to mention, no device that has shown effective assistance and biomimetic behavior across different walking speeds and terrains. This thesis aims to build a Leg Exoskeleton Simulator to effectively search the space of potential prosthetic and orthotic design, control, and sensing strategies so as to find the best means to improve human locomotion through wearable electromechanical technology and modern bionics, enabling rapid advancement of the human-machine interface. This thesis presents the MIT Exoskeleton Simulator, which is a modular tethered system that includes cable-drive mechanisms along with off-board power, actuation, control hardware, and wearable end-effector modules. In order to effectively transmit force to a wearable end-effector module, high-performance cable-drive modules with the Rolling Cable Transmission for both unidirectional actuation and bidirectional actuation were developed. A new Adaptive Coupling Joint design principle was proposed for designing a simple mechanical interface that can transmit pure torque from an input actuation source to any biological joint without altering the biological joint motions. The Simulator has been controlled with a bio-inspired control based controller that emulates the behavior of human morphology and neural control for the non-amputee participants. In this thesis, I tried to provide a base of knowledge regarding effective design, control, and sensing strategies for effective human augmentation. In the near future, more criteria can be further established for building effective leg exoskeletons that will improve the ambulatory speed, metabolic economy, and stability of walking humans. The Simulator could potentially enhance the ambulation of able-bodied persons or individuals with movement pathology, as well as providing the treatment or relief of gait dysfunction resulting from movement pathology, or restoration of age-related reduced locomotory function.

Download or read book Mathematical Models of Exoskeleton written by Andrey Valerievich Borisov and published by Springer Nature. This book was released on 2022-03-31 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the current state of the problem of describing the musculoskeletal system of a person. Models of the destruction of the endoskeleton and the restoration of its functions using exoskeleton are presented. A description is given of new approaches to modeling based on the use of weightless rods of variable length with concentrated masses. The practical application to the tasks of numerical simulation of the movements of the musculoskeletal system of a person is described. Exoskeleton models with variable-length units based on absolutely hard sections and sections that change their telescopic type length have been developed. The book is intended for specialists in the field of theoretical mechanics, biomechanics, robotics and related fields. The book will be useful to teachers, as well as graduate students, undergraduates and senior students of higher educational institutions, whose research interests lie in the modeling of anthropomorphic biomechanical systems.

Download or read book Wearable Robotics Challenges and Trends written by Juan C. Moreno and published by Springer Nature. This book was released on 2021-07-01 with total page 675 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reports on advanced topics in the areas of wearable robotics research and practice. It focuses on new technologies, including neural interfaces, soft wearable robots, sensors and actuators technologies, discussing industrially and medically-relevant issues, as well as legal and ethical aspects. It covers exemplary case studies highlighting challenges related to the implementation of wearable robots for different purposes, and describing advanced solutions. Based on the 5th International Symposium on Wearable Robotics, WeRob2020, and on WearRacon Europe 2020, which were both held online on October 13-16, 2020, the book addresses a large audience of academics and professionals working in for the government, in the industry, and in medical centers, as well as end-users alike. By merging together engineering, medical, ethical and industrial perspectives, it offers a multidisciplinary, timely snapshot of the field of wearable technologies.

Download or read book Assisting Walking in Individuals with Chronic Stroke Using Exoskeletons written by Thu M. Nguyen and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Stroke often results in hemiparesis and gait asymmetries, such as spatial, temporal, or kinematic asymmetries between the paretic and nonparetic legs. Asymmetric gaits have been correlated with higher metabolic cost, slower walking speeds, and lower mobility. These gaits can also cause joint pain due to repetitive high loads on the nonparetic limb. For these reasons, physical therapists try to decrease gait asymmetries, and their interventions have been shown to be effective. However, sessions are expensive, limiting access. More automated rehabilitation techniques have been developed, but they have not been more effective than conventional physical therapy. A better understanding of the mechanisms driving gait asymmetry could allow for the development of more targeted, effective, and accessible gait interventions. In my doctoral research, I first studied the correlation between step length asymmetry and metabolic cost in individuals with chronic stroke and in unimpaired participants. Participants were tasked with altering their step length asymmetry using biofeedback. All participants were able to significantly alter their step length asymmetry. Unimpaired participants self-selected a symmetric step length asymmetry that correlated to the lowest energy cost. However, for individuals with chronic stroke, metabolic cost minimization did not explain self-selected step length asymmetry. I then built a unilateral knee-ankle exoskeleton emulator that can actuate knee flexion, knee extension, and ankle plantarflexion. I designed a knee position controller to track desirable knee kinematics and demonstrated the mechatronic capabilities of the emulator system on one unimpaired participant and one participant with chronic stroke. The knee position controller was able to prevent negative impacts at the knee when plantarflexion torques were applied, and the position controller could track different desired knee trajectories with low tracking error. The results from these studies could better inform the design of future rehabilitation tools and assistive devices. Our results suggest that metabolic energy consumption probably will not be a barrier to therapists who seek to improve step length asymmetry. Additionally, we found that active ankle plantarflexion assistance can cause increased knee extension which might lead to long-term tissue damage with constant use. Assistive devices simultaneously assisting the ankle and knee could prevent these poor knee responses. This might allow for a more comfortable application of larger magnitude ankle torques which could potentially improve metabolic reductions. These projects have led to a new experimental tool that can be used to discover beneficial participant-specific assistance strategies for individuals with chronic stroke.

Download or read book Development and Testing of a Polycentric Knee Joint for Powered Walking Assist Exoskeletons written by Émélie Séguin and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Loss of mobility and independence directly affects the quality of life of many vulnerable individuals. To address this, researchers have developed wearable walking assist exoskeletons to aid users with their daily activities. While this technology has advanced tremendously in the past decade, current exoskeletons cause discomfort and injuries to the user, leading to device rejection. This research intends to develop a kinematically compatible knee joint suitable for exoskeletons. The proposed knee design can be adapted to accommodate an offset and optimize force delivery. This is achieved by ensuring that the mechanical and biological joint rotation axes are aligned and that the moment arm varies throughout flexion. Model simulations and mechanical testing of fabricated prototypes were achieved to analyze and validate the design. The results confirm the kinematic compatibility of the design and that the moment arm could be varied throughout flexion to achieve optimal and effective moment transfer.

Download or read book An Exoskeleton Device to Assist in Downhill Walking written by Matt Yarri and published by . This book was released on 2014 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development and Testing of Passive Walking Assistive Exoskeleton with Upward Force Assist written by Zlatko Lovrenovic and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An aging population and rising prevalence in obesity, arthritis and diabetes are resulting in a great number of elders that are suffering from mobility challenges. Walking assist exoskeletons have the potential to help preserve mobility in elders. The most common type of exoskeleton relies on heavily, complex and expensive components to help their user walk effortlessly. Recent research on walking assist exoskeletons has shifted towards the creation of an entirely mechanical system called passive walking assist exoskeleton. This research aims to design, model and test a passive walking assist exoskeleton that reduces the felt weight of the user during gait. The assist is achieved by the action of a seat mechanism which constantly produces an upward force on the pelvis of the user. This thesis details the entire composition and assembly of such device. The proposed device was modelled in order to predict the assistance provided by the seat mechanism when standing and walking with the device. A human-sized prototype was built and tested in order to mechanically validate the proposed design. The test results validated the proposed seat mechanism which produces the desired upward force, but the use of the exoskeleton in its current state hindered the natural gait pattern of the user.