Event-based control for sit-to-stand transition using a wearable exoskeleton

Rajasekaran, Vijaykumar; Vinagre, Manuel; Aranda, Joan

doi:10.1109/icorr.2017.8009280

Cited by 17 publications

(13 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Event based control approaches are highly appreciated in combinational therapies to make an efficient use of the appropriate tools at different stages of the gait cycle. These event-based gait initiation ensures the real time coordination among the different tools and improves the rehabilitation training methodology [ 24 , 54 – 56 ]. Finite state machine (FSM) based BMI correlation with movements are also been used to improve the efficacy of the volitional orders in rehabilitation [ 40 ].…”

Section: Methodsmentioning

confidence: 99%

Volition-adaptive control for gait training using wearable exoskeleton: preliminary tests with incomplete spinal cord injury individuals

Rajasekaran

López‐Larraz

Trincado-Alonso

et al. 2018

J NeuroEngineering Rehabil

Self Cite

View full text Add to dashboard Cite

BackgroundGait training for individuals with neurological disorders is challenging in providing the suitable assistance and more adaptive behaviour towards user needs. The user specific adaptation can be defined based on the user interaction with the orthosis and by monitoring the user intentions. In this paper, an adaptive control model, commanded by the user intention, is evaluated using a lower limb exoskeleton with incomplete spinal cord injury individuals (SCI).MethodsA user intention based adaptive control model has been developed and evaluated with 4 incomplete SCI individuals across 3 sessions of training per individual. The adaptive control model modifies the joint impedance properties of the exoskeleton as a function of the human-orthosis interaction torques and the joint trajectory evolution along the gait sequence, in real time. The volitional input of the user is identified by monitoring the neural signals, pertaining to the user’s motor activity. These volitional inputs are used as a trigger to initiate the gait movement, allowing the user to control the initialization of the exoskeleton movement, independently. A Finite-state machine based control model is used in this set-up which helps in combining the volitional orders with the gait adaptation.ResultsThe exoskeleton demonstrated an adaptive assistance depending on the patients’ performance without guiding them to follow an imposed trajectory. The exoskeleton initiated the trajectory based on the user intention command received from the brain machine interface, demonstrating it as a reliable trigger. The exoskeleton maintained the equilibrium by providing suitable assistance throughout the experiments. A progressive change in the maximum flexion of the knee joint was observed at the end of each session which shows improvement in the patient performance. Results of the adaptive impedance were evaluated by comparing with the application of a constant impedance value. Participants reported that the movement of the exoskeleton was flexible and the walking patterns were similar to their own distinct patterns.ConclusionsThis study demonstrates that user specific adaptive control can be applied on a wearable robot based on the human-orthosis interaction torques and modifying the joints’ impedance properties. The patients perceived no external or impulsive force and felt comfortable with the assistance provided by the exoskeleton. The main goal of such a user dependent control is to assist the patients’ needs and adapt to their characteristics, thus maximizing their engagement in the therapy and avoiding slacking. In addition, the initiation directly controlled by the brain allows synchronizing the user’s intention with the afferent stimulus provided by the movement of the exoskeleton, which maximizes the potentiality of the system in neuro-rehabilitative therapies.

show abstract

Section: Methodsmentioning

confidence: 99%

Volition-adaptive control for gait training using wearable exoskeleton: preliminary tests with incomplete spinal cord injury individuals

Rajasekaran

López‐Larraz

Trincado-Alonso

et al. 2018

J NeuroEngineering Rehabil

Self Cite

View full text Add to dashboard Cite

show abstract

“…Como se observa en la Figura 7, los eslabones no quedan totalmente verticales como se muestra en la Figura 5, esto es debido a la posición natural del humano. Esta secuencia se puede apreciar de manera similar a la reportada en (Rajasekaran, 2017), donde un usuario utiliza un exoesqueleto de extremidades inferiores. También, es importante mencionar que los valores obtenidos en estas simulaciones, son similares a los reportados por otros autores al analizar los torques en las articulaciones de una persona, cuando realiza la transición de sentadoparado, como se menciona en (Lara, 2015).…”

Section: Casounclassified

“…No reportan el torque requerido. Otro exoesqueleto, para la transición de sentarse-levantarse, denominado H1 es presentado en (Rajasekaran, 2017). Los autores proponen un control basado en eventos (control acoplado de amortiguamiento-rigidez), con un perfil de velocidad trapezoidal para la transición.…”

Section: Introductionunclassified

Controlador robusto para el seguimiento de trayectorias para un exoesqueleto de extremidades inferiores

Ortega

Pérez-Vigueras

Antúnez-Leyva

et al. 2019

JME

View full text Add to dashboard Cite

Currently, robotics has shown that it can increase the efficiency in the specific rehabilitation of some of the limbs of the human body, in this case assisting people who have suffered a stroke, by using devices such as exoskeletons, to provide continuous, smooth and controlled movements. Stroke is the result of a shortage of the brain that leads in just a few minutes to cell death, causing severe damage to the human body, even death of the patient. People who have suffered a stroke have difficulty rising from a chair. An exoskeleton is a mechanical structure designed to be used on the human body as a garment, it serves as a support and is used to assist movements or accentuate strength as a support in a person. Lower extremity exoskeleton can assist patients with hemiplegia to get up or sit on a chair, thus avoiding muscle atrophy and possible spasticity. This paper proposes the use of a robust Generalized Proportional Integral (GPI) controller for trajectory tracking for controlling a six degrees of freedom exoskeleton, to assist patients when getting up and sitting down from a chair. Simulation results obtained with the virtual prototype of the exoskeleton, under the environment of the MSC Adams software in co-simulation with Matlab are presented.

show abstract

“…Even though the "inherent stability" of a static motion appears to be more desirable than a dynamic motion, the severe constraints required by the trajectory are often incompatible with hardware limitations (e.g., joint torque limits). External force from the user, either by pushing downward on the arms of a chair, crutches, or FES [12], have been used to achieve assisted sit-to-stand motions. Allowing for the user to apply an external force can enhance stability of the motion as well as user confidence in the motion.…”

Section: Introduction a Motivationmentioning

confidence: 99%

Feedback Control Design for Robust Comfortable Sit-to-Stand Motions of 3D Lower-Limb Exoskeletons

Mungai

Grizzle

2021

IEEE Access

View full text Add to dashboard Cite

Event-based control for sit-to-stand transition using a wearable exoskeleton

Cited by 17 publications

References 12 publications

Volition-adaptive control for gait training using wearable exoskeleton: preliminary tests with incomplete spinal cord injury individuals

Volition-adaptive control for gait training using wearable exoskeleton: preliminary tests with incomplete spinal cord injury individuals

Controlador robusto para el seguimiento de trayectorias para un exoesqueleto de extremidades inferiores

Feedback Control Design for Robust Comfortable Sit-to-Stand Motions of 3D Lower-Limb Exoskeletons

Contact Info

Product

Resources

About