The Experts below are selected from a list of 642 Experts worldwide ranked by ideXlab platform

Aaron M. Dollar - One of the best experts on this subject based on the ideXlab platform.

  • Design and Functional Evaluation of a Quasi-Passive Compliant Stance Control Knee–Ankle–Foot Orthosis
    IEEE Transactions on Neural Systems and Rehabilitation Engineering, 2014
    Co-Authors: Kamran Shamaei, Paul C. Napolitano, Aaron M. Dollar
    Abstract:

    In this paper, we present the mechanical design, control algorithm, and functional evaluation of a quasi-passive compliant stance control Knee-Ankle-Foot Orthosis. The Orthosis implements a spring in parallel with the knee joint during the stance phase of the gait and allows free rotation during the swing phase. The design is inspired by the moment-angle analysis of the knee joint revealing that the knee function approximates that of a linear torsional spring in the stance phase of the gait. Our Orthosis aims to restore the natural function of a knee that is impaired by injury, stroke, post-polio, multiple sclerosis, spinal cord injury, patellofemoral pain syndrome, osteoarthritis, and others. Compared with state-of-the-art stance control orthoses, which rigidly lock the knee during the stance phase, the described Orthosis intends to provide the natural shock absorption function of the knee in order to reduce compensatory movements both in the affected and unaffected limbs. Preliminary testing on three unimpaired subjects showed that compliant support of the knee provided by the Orthosis explained here results in higher gait speed as well as more natural kinematic profiles for the lower extremities when compared with rigid support of the knee provided by an advanced commercial stance control Orthosis.

  • A quasi-passive compliant stance control Knee-Ankle-Foot Orthosis
    2013 IEEE 13th International Conference on Rehabilitation Robotics (ICORR), 2013
    Co-Authors: Kamran Shamaei, Paul C. Napolitano, Aaron M. Dollar
    Abstract:

    In this paper, we present the design of a novel quasi-passive stance-control Orthosis that implements a natural amount of knee compliance during the weight acceptance phase and potentially the entire stance phase of the gait, and allows for free motion during the rest of the gait. We explain that the unaffected knee behaves close to a linear torsional spring in stance and hypothesize that an assistive device that places a linear spring of appropriate stiffness in parallel with the knee can help restore the natural behavior of the joint in stance. We present the design of a friction-based latching mechanism and a control algorithm that engages the spring in parallel with the knee in stance and disengages it during the swing phase of gait, and explain how this module is implemented into a brace in order to create a novel class of compliant stance control Orthosis. The device is quasi-passive in that a small actuator serves to lock and unlock the spring module, but the device otherwise requires no actuation and very little power, computation, and control to operate.

  • ICORR - A quasi-passive compliant stance control Knee-Ankle-Foot Orthosis
    IEEE ... International Conference on Rehabilitation Robotics : [proceedings], 2013
    Co-Authors: Kamran Shamaei, Paul C. Napolitano, Aaron M. Dollar
    Abstract:

    In this paper, we present the design of a novel quasi-passive stance-control Orthosis that implements a natural amount of knee compliance during the weight acceptance phase and potentially the entire stance phase of the gait, and allows for free motion during the rest of the gait. We explain that the unaffected knee behaves close to a linear torsional spring in stance and hypothesize that an assistive device that places a linear spring of appropriate stiffness in parallel with the knee can help restore the natural behavior of the joint in stance. We present the design of a friction-based latching mechanism and a control algorithm that engages the spring in parallel with the knee in stance and disengages it during the swing phase of gait, and explain how this module is implemented into a brace in order to create a novel class of compliant stance control Orthosis. The device is quasi-passive in that a small actuator serves to lock and unlock the spring module, but the device otherwise requires no actuation and very little power, computation, and control to operate.

Mokhtar Arazpour - One of the best experts on this subject based on the ideXlab platform.

  • The effect of 'Sensor Lock', a knee–ankle–foot Orthosis with an electromechanical stance control knee joint, on walking parameters and gait symmetry of subjects with quadriceps weakness: a pilot study
    Spinal cord series and cases, 2017
    Co-Authors: Farnoosh Asadi, Mokhtar Arazpour, Monireh Ahmadi Bani, Gholamreza Aminian, Reza Vahab Kashani
    Abstract:

    Pilot study. This study aimed to evaluate an electromechanical stance control (SC) knee joint, 'sensor lock', which could potentially solve the problems of walking parameters and gait symmetry in subjects with poliomyelitis. University of Social Welfare and Rehabilitation Sciences. Six subjects with quadriceps weakness were enrolled in this study. A custom-made stance-control knee–ankle–foot Orthosis (SCKAFO) with the same set of components was constructed for each participant. A motion analysis system was used for analysis of lower limb kinematics. There were no significant differences between the knee–ankle–foot orthoses (KAFOs) and the two types of knee joints with regard to temporal–spatial parameters. Walking speed and cadence reduced and stride length increased in the stance control (SC) mode compared to the knee joint locked mode. The maximum knee flexion angle during swing phase increased when walking with SC mode compared to walking with the KAFO in knee joint lock mode. There was a significant difference between two test conditions with regard to hip flexion. There were only significant differences in the symmetry index of the knee flexion between two test conditions. Compared to locked knee mode, SC mode demonstrated a slower speed of walking and increased peak knee flexion during swing. Regarding gait symmetry, the symmetry index of the knee flexion and speed of walking decreased when the KAFO with SC mode was used compared to KAFO with knee joint locked mode.

  • Design, construction, and evaluation of “sensor lock”: an electromechanical stance control knee joint
    Disability and Rehabilitation: Assistive Technology, 2017
    Co-Authors: Mokhtar Arazpour, Mohammad Samadian, Monireh Ahmadi Bani, Mina Arab Baniasad, Navid Golchin
    Abstract:

    AbstractBackground and aim: Most currently-available stance control knee ankle foot orthoses (SCKAFOs) still need full knee extension to lock the knee joint, and they are still noisy, bulky, and heavy. Therefore, the aim of this study was to design, construct, and evaluate an original electromechanical SCKAFO knee joint that could feasibly solve these problems, and thus address the problems of current stance control knee joints with regards to their structure, function, cosmesis, and cost.Method: Ten able-bodied (AB) participants and two (knee ankle foot Orthosis) KAFO users were recruited to participate in the study. A custom SCKAFO with the same set of components was constructed for each participant. Lower limb kinematics were captured using a 6-camera, video-based motion analysis system.Results: For AB participants, significant differences were found between normal walking and walking with the SCKAFO for temporal-spatial parameters and between orthoses with two modes of knee joints in the healthy subje...

  • Evaluation of gait symmetry in poliomyelitis subjects: Comparison of a conventional knee–ankle–foot Orthosis and a new powered knee–ankle–foot Orthosis:
    Prosthetics and Orthotics International, 2015
    Co-Authors: Mokhtar Arazpour, Mohammad Samadian, Mahmood Bahramizadeh, Monireh Ahmadi Bani, Fardin Ahmadi, Mohammad Ebrahim Mousavi, Stephen W Hutchins
    Abstract:

    Background: Compared to able-bodied subjects, subjects with post polio syndrome and poliomyelitis demonstrate a preference for weight-bearing on the non-paretic limb, causing gait asymmetry. Objectives: The purpose of this study was to evaluate the gait symmetry of the poliomyelitis subjects when ambulating with either a drop- locked knee ankle foot Orthosis (KAFO) or a newly developed powered KAFO. Methods: Seven subjects with poliomyelitis who routinely wore conventional KAFOs participated in this study, and received training to enable them to ambulate with the powered KAFO on level ground, prior to gait analysis. Results: There were no significant differences in the gait symmetry index (SI) of step length (P=0.085), stance time (P=0.082), double limb support time (P=0.929) or speed of walking (p=0.325) between the two test conditions. However, using the new powered KAFO improved the SI in step width (P=0.037), swing time (P=0.014), stance phase percentage (P=0.008) and knee flexion during swing phase (p≤0.001) compared to wearing the dropped locked KAFO. Conclusion: The use of a powered KAFO for ambulation by poliomyelitis subjects affects gait symmetry in the base of support, swing time, stance phase percentage and knee flexion during swing phase.

  • The physiological cost index of walking with a powered knee–ankle–foot Orthosis in subjects with poliomyelitis: A pilot study
    Prosthetics and Orthotics International, 2015
    Co-Authors: Mokhtar Arazpour, Mohammad Samadian, Mahmood Bahramizadeh, Monireh Ahmadi Bani, Stephen W Hutchins, Mohammad Ebrahim Mousavi, Sarah Curran, Mohammad Ali Mardani
    Abstract:

    Background:A powered knee–ankle–foot Orthosis was developed to provide restriction of knee flexion during stance phase and active flexion and extension of the knee during swing phase of gait.Objective:The purpose of this study was to determine its effect on the physiological cost index, walking speed and the distance walked in people with poliomyelitis compared to when walking with a knee–ankle–foot Orthosis with drop lock knee joints.Study design:Quasi experimental study.Methods:Seven subjects with poliomyelitis volunteered for the study and undertook gait analysis with both types of knee–ankle–foot Orthosis.Results:Walking with the powered knee–ankle–foot Orthosis significantly reduced walking speed (p = 0.015) and the distance walked (p = 0.004), and also, it did not improve physiological cost index values (p = 0.009) compared to walking with the locked knee–ankle–foot Orthosis.Conclusion:Using a powered knee–ankle–foot Orthosis did not significantly improve any of the primary outcome measures during w...

  • The influence of a powered Knee-Ankle-Foot Orthosis on walking in poliomyelitis subjects: A pilot study
    Prosthetics and Orthotics International, 2015
    Co-Authors: Mokhtar Arazpour, Alireza Moradi, Mohammad Samadian, Mahmood Bahramizadeh, Mahmoud Joghtaei, Monireh Ahmadi Bani, Stephen W Hutchins, Mohammad Ali Mardani
    Abstract:

    Background: Traditionally, the anatomical knee joint is locked in extension when walking with a conventional Knee-Ankle-Foot Orthosis. A powered Knee-Ankle-Foot Orthosis was developed to provide restriction of knee flexion during stance phase and active flexion and extension of the knee during swing phase of gait. Objective: The purpose of this study was to determine differences of the powered Knee-Ankle-Foot Orthosis compared to a locked Knee-Ankle-Foot Orthosis in kinematic data and temporospatial parameters during ambulation. Study design: Quasi-experimental design. Methods: Subjects with poliomyelitis (n = 7) volunteered for this study and undertook gait analysis with both the powered and the conventional Knee-Ankle-Foot orthoses. Three trials per Orthosis were collected while each subject walked along a 6-m walkway using a calibrated six-camera three-dimensional video-based motion analysis system. Results: Walking with the powered Knee-Ankle-Foot Orthosis resulted in a significant reduction in both walking speed and step length (both 18%), but a significant increase in stance phase percentage compared to walking with the conventional Knee-Ankle-Foot Orthosis. Cadence was not significantly different between the two test conditions (p = 0.751). There was significantly higher knee flexion during swing phase and increased hip hiking when using the powered Orthosis. Conclusion: The new powered Orthosis permitted improved knee joint kinematic for Knee-Ankle-Foot Orthosis users while providing knee support in stance and active knee motion in swing in the gait cycle. Therefore, the new powered Orthosis provided more natural knee flexion during swing for Orthosis users compared to the locked Knee-Ankle-Foot Orthosis.

Francisco Ávila Romero - One of the best experts on this subject based on the ideXlab platform.

  • Design of a patient-tailored active Knee-Ankle-Foot Orthosis to assist the gait of spinal cord injured subjects
    2020
    Co-Authors: Josep Maria Font Llagunes, Urbano Lugrís Armesto, Francisco Ávila Romero, Daniel Clos Costa, F. J. Alonso, Javier Cuadrado Aranda
    Abstract:

    —This paper presents the main design steps in the development of an active Knee-Ankle-Foot Orthosis (KAFO) conceived to assist the gait of incomplete spinal cord injured (SCI) subjects. The design approach is based on the idea of modifying the available passive orthoses by adding adaptable mechatronic modules at the joints. This approach has resulted in a prototype that has been tested on SCI patients. The design and control problems found and their adopted solutions are thoroughly described.

  • Controller Design for A Stance-Control Knee-Ankle-Foot Orthosis Based on Optimization Techniques
    arXiv: Adaptation and Self-Organizing Systems, 2012
    Co-Authors: S. H. Hosseinnia, Francisco Ávila Romero, F. J. Alonso, I. Tejado, Blas M. Vinagre
    Abstract:

    Design of active Orthosis is a challenging problem from both the dynamic simulation and control points of view. The redundancy problem of the simultaneous human-Orthosis actuation is an interesting exercise to solve concerning the analytical and computational cost effectiveness. The physiological static optimization approach tries to solve the actuation sharing problem. Its objective is to quantify the contributions of muscles and active Orthosis to the net joint torques in order to select the proper actuator for the joint. Depending on the disability of each patient, different controllers can be designed. As a matter of fact, the duration of the gait cycle for each patient should be different. In this paper, a PI controller is designed whose parameters are tuned by optimizing a cost function which takes into account the patients muscle power and the error of the knee angle with the reference value. Moreover, the final time is obtained by minimizing the mean of integral squared errors. The performance of the method is shown by designing the controller for three types of patients, ordered from low to high disability. The objective of this work is to use optimal control techniques based on physiological static optimization approach to the design of active Orthosis and its control.

  • BIODEVICES - Controller Design for A Stance-Control Knee-Ankle-Foot Orthosis Based on Optimization Techniques
    2012
    Co-Authors: S. H. Hosseinnia, Francisco Ávila Romero, F. J. Alonso, Blas M. Vinagre, I. Tejado
    Abstract:

    Dept. of Mechanical Engineering, Energetics and Materials, University of Extremadura,Avda de Elvas S/N, Badajoz, Spainfhoseinnia, bvinagre, fjas, itejbalg@unex.es, fromeros@alumnos.unex.esKeywords: Active Orthosis, Biomechanics, Muscle Modeling, Optimization, Optimal Control.Abstract: Design of active Orthosis is a challenging problem from both the dynamic simulation and control points ofview. The redundancy problem of the simultaneous human-Orthosis actuation is an interesting exercise tosolve concerning the analytical and computational cost effectiveness. The physiological static optimizationapproach tries to solve the actuation sharing problem. Its objective is to quantify the contributions of musclesand active Orthosis to the net joint torques in order to select the proper actuator for the joint. Depending onthe disability of each patient, different controllers can be designed. As a matter of fact, the duration of thegait cycle for each patient should be different. In this paper, a PI controller is designed whose parameters aretuned by optimizing a cost function which takes into account the patients muscle power and the error of theknee angle with the reference value. Moreover, the final time is obtained by minimizing the mean of integralsquared errors. The performance of the method is shown by designing the controller for three types of patients,ordered from low to high disability. The objective of this work is to use optimal control techniques based onphysiological static optimization approach to the design of active Orthosis and its control.

  • ISABEL - A powered lower limb Orthosis for gait assistance in incomplete spinal cord injured subjects
    Proceedings of the 4th International Symposium on Applied Sciences in Biomedical and Communication Technologies - ISABEL '11, 2011
    Co-Authors: Josep M. Font-llagunes, G. Arroyo, Gil Serrancolí, Francisco Ávila Romero
    Abstract:

    The paper deals with the mechanical design of a new active stance-control Knee-Ankle-Foot Orthosis (SCKAFO). The Orthosis is intended to provide gait assistance for incomplete spinal cord injured patients that present functional hip muscles, but partially denervated knee and ankle muscles. It consists of a passive compliant joint that constrains ankle plantar flexion, along with a powered knee unit that prevents knee flexion during stance and controls flexion-extension during swing. For this purpose, the knee joint incorporates a controllable mechanical locking system and an electrical DC motor that actuate independently. The prototype is equipped with different sensors (plantar sensors and angular encoders) for control purposes. They are used to identify the main events defining the gait phases and to provide feedback measurements for the motor control system.

  • HYBRID MODELING AND FRACTIONAL CONTROL OF A SCKAFO Orthosis FOR GAIT ASSISTANCE
    Volume 3: 2011 ASME IEEE International Conference on Mechatronic and Embedded Systems and Applications Parts A and B, 2011
    Co-Authors: S. Hassan Hosseinnia, Francisco Ávila Romero, F. J. Alonso, Blas M. Vinagre, Inés Tejado, Josep M. Font-llagunes
    Abstract:

    SCKAFO, stance-control Knee-Ankle-Foot Orthosis, is a type of Orthosis that permits free knee motion during swing while resisting knee flexion during stance, supporting thereby the limb during weight bearing. This Orthosis specially assists patients who have incomplete spinal cord injury and allows them to walk with the aid of canes or crutches, maintaining a proper gait. In this paper, based on the human walking biomechanics, the SCKAFO hybrid modeling is proposed, which consists of eight different stages whose evolution is given by means of four planar sensors on each foot. In the model, it is considered that the patients can move their hip but not their knee that will be controlled using a DC motor. Two fractional order controllers are designed, following decision based control techniques, to control the knee angle. Simulation results are given in order to demonstrate the efficiency of the system performance.

Stephen W Hutchins - One of the best experts on this subject based on the ideXlab platform.

  • Effect of a Knee-Ankle-Foot Orthosis on knee kinematics and kinetics in an individual with varus knee alignment
    Jpo Journal of Prosthetics and Orthotics, 2016
    Co-Authors: Huda H. Alfatafta, Stephen W Hutchins, Richard Jones
    Abstract:

    Background: Knee valgus braces are used to reduce knee load and varus deformities in individuals with medial compartment osteoarthritis (OA). The purpose of this study was to determine whether the kinematics and kinetics of the knee are improved when wearing a Knee-Ankle-Foot Orthosis (KAFO) compared with knee valgus braces while walking and stair climbing. Materials and Methods: One male individual (with 10° of knee varus) was assessed with a control shoe, custom, and off-the-shelf (OTS) Unloader knee valgus braces, and a custom-made KAFO in situ during walking and stair climbing. Results: The KAFO significantly reduced the knee varus angle compared with the shoe and both knee valgus braces during walking and stair climbing, as well as the first peak of the external knee adduction moment (EKAM) during walking and the knee adduction angular impulse (KAAI) during ascending compared with the shoe. No significant differences were noted between the custom and OTS knee valgus braces in any measures. Conclusions: Knee-Ankle-Foot orthoses may be recommended for individuals with high knee varus angles.

  • Evaluation of gait symmetry in poliomyelitis subjects: Comparison of a conventional knee–ankle–foot Orthosis and a new powered knee–ankle–foot Orthosis:
    Prosthetics and Orthotics International, 2015
    Co-Authors: Mokhtar Arazpour, Mohammad Samadian, Mahmood Bahramizadeh, Monireh Ahmadi Bani, Fardin Ahmadi, Mohammad Ebrahim Mousavi, Stephen W Hutchins
    Abstract:

    Background: Compared to able-bodied subjects, subjects with post polio syndrome and poliomyelitis demonstrate a preference for weight-bearing on the non-paretic limb, causing gait asymmetry. Objectives: The purpose of this study was to evaluate the gait symmetry of the poliomyelitis subjects when ambulating with either a drop- locked knee ankle foot Orthosis (KAFO) or a newly developed powered KAFO. Methods: Seven subjects with poliomyelitis who routinely wore conventional KAFOs participated in this study, and received training to enable them to ambulate with the powered KAFO on level ground, prior to gait analysis. Results: There were no significant differences in the gait symmetry index (SI) of step length (P=0.085), stance time (P=0.082), double limb support time (P=0.929) or speed of walking (p=0.325) between the two test conditions. However, using the new powered KAFO improved the SI in step width (P=0.037), swing time (P=0.014), stance phase percentage (P=0.008) and knee flexion during swing phase (p≤0.001) compared to wearing the dropped locked KAFO. Conclusion: The use of a powered KAFO for ambulation by poliomyelitis subjects affects gait symmetry in the base of support, swing time, stance phase percentage and knee flexion during swing phase.

  • The physiological cost index of walking with a powered knee–ankle–foot Orthosis in subjects with poliomyelitis: A pilot study
    Prosthetics and Orthotics International, 2015
    Co-Authors: Mokhtar Arazpour, Mohammad Samadian, Mahmood Bahramizadeh, Monireh Ahmadi Bani, Stephen W Hutchins, Mohammad Ebrahim Mousavi, Sarah Curran, Mohammad Ali Mardani
    Abstract:

    Background:A powered knee–ankle–foot Orthosis was developed to provide restriction of knee flexion during stance phase and active flexion and extension of the knee during swing phase of gait.Objective:The purpose of this study was to determine its effect on the physiological cost index, walking speed and the distance walked in people with poliomyelitis compared to when walking with a knee–ankle–foot Orthosis with drop lock knee joints.Study design:Quasi experimental study.Methods:Seven subjects with poliomyelitis volunteered for the study and undertook gait analysis with both types of knee–ankle–foot Orthosis.Results:Walking with the powered knee–ankle–foot Orthosis significantly reduced walking speed (p = 0.015) and the distance walked (p = 0.004), and also, it did not improve physiological cost index values (p = 0.009) compared to walking with the locked knee–ankle–foot Orthosis.Conclusion:Using a powered knee–ankle–foot Orthosis did not significantly improve any of the primary outcome measures during w...

  • The influence of a powered Knee-Ankle-Foot Orthosis on walking in poliomyelitis subjects: A pilot study
    Prosthetics and Orthotics International, 2015
    Co-Authors: Mokhtar Arazpour, Alireza Moradi, Mohammad Samadian, Mahmood Bahramizadeh, Mahmoud Joghtaei, Monireh Ahmadi Bani, Stephen W Hutchins, Mohammad Ali Mardani
    Abstract:

    Background: Traditionally, the anatomical knee joint is locked in extension when walking with a conventional Knee-Ankle-Foot Orthosis. A powered Knee-Ankle-Foot Orthosis was developed to provide restriction of knee flexion during stance phase and active flexion and extension of the knee during swing phase of gait. Objective: The purpose of this study was to determine differences of the powered Knee-Ankle-Foot Orthosis compared to a locked Knee-Ankle-Foot Orthosis in kinematic data and temporospatial parameters during ambulation. Study design: Quasi-experimental design. Methods: Subjects with poliomyelitis (n = 7) volunteered for this study and undertook gait analysis with both the powered and the conventional Knee-Ankle-Foot orthoses. Three trials per Orthosis were collected while each subject walked along a 6-m walkway using a calibrated six-camera three-dimensional video-based motion analysis system. Results: Walking with the powered Knee-Ankle-Foot Orthosis resulted in a significant reduction in both walking speed and step length (both 18%), but a significant increase in stance phase percentage compared to walking with the conventional Knee-Ankle-Foot Orthosis. Cadence was not significantly different between the two test conditions (p = 0.751). There was significantly higher knee flexion during swing phase and increased hip hiking when using the powered Orthosis. Conclusion: The new powered Orthosis permitted improved knee joint kinematic for Knee-Ankle-Foot Orthosis users while providing knee support in stance and active knee motion in swing in the gait cycle. Therefore, the new powered Orthosis provided more natural knee flexion during swing for Orthosis users compared to the locked Knee-Ankle-Foot Orthosis.

  • The gait and energy efficiency of stance control knee–ankle–foot orthoses: A literature review
    Prosthetics and Orthotics International, 2015
    Co-Authors: Masoud Rafiaei, Mokhtar Arazpour, Mohammad Samadian, Mahmood Bahramizadeh, Stephen W Hutchins, Farzam Farahmand, Mohammad Ali Mardani
    Abstract:

    Background: The use of knee–ankle–foot orthoses with drop locked knee joints produces some limitations for walking in subjects with quadriceps muscle weakness. The development of stance control orthoses can potentially improve their functionality. Objectives: The aim of this review was to compare the evidence of the effect of stance control orthoses to knee–ankle–foot orthoses with drop locked knee joints in improving kinematic variables and energy efficiency of walking by subjects with quadriceps muscle weakness caused by different pathologies. Study design: Literature review. Methods: Based on selected keywords and their composition, a search was performed in Google Scholar, PubMed, ScienceDirect, and ISI Web of Knowledge databases. In total, 18 articles were finally chosen for review. Results: The results of this study demonstrated that this type of Orthosis can improve the walking parameters of subjects with quadriceps muscle weakness and spinal cord injury patients when compared to a locked knee–ankle–foot Orthosis. Conclusion: There is evidence to show that stance control Orthosis designs improve the gait kinematics but not energetic of knee–ankle–foot Orthosis users. Development of new designs of stance control orthoses to provide a more normal pattern of walking is still required. Clinical relevance Stance control orthoses are a new generation of orthotic intervention that could potentially be significant in assisting to improve the gait kinematics by knee–ankle–foot Orthosis users.

Kamran Shamaei - One of the best experts on this subject based on the ideXlab platform.

  • Design and Functional Evaluation of a Quasi-Passive Compliant Stance Control Knee–Ankle–Foot Orthosis
    IEEE Transactions on Neural Systems and Rehabilitation Engineering, 2014
    Co-Authors: Kamran Shamaei, Paul C. Napolitano, Aaron M. Dollar
    Abstract:

    In this paper, we present the mechanical design, control algorithm, and functional evaluation of a quasi-passive compliant stance control Knee-Ankle-Foot Orthosis. The Orthosis implements a spring in parallel with the knee joint during the stance phase of the gait and allows free rotation during the swing phase. The design is inspired by the moment-angle analysis of the knee joint revealing that the knee function approximates that of a linear torsional spring in the stance phase of the gait. Our Orthosis aims to restore the natural function of a knee that is impaired by injury, stroke, post-polio, multiple sclerosis, spinal cord injury, patellofemoral pain syndrome, osteoarthritis, and others. Compared with state-of-the-art stance control orthoses, which rigidly lock the knee during the stance phase, the described Orthosis intends to provide the natural shock absorption function of the knee in order to reduce compensatory movements both in the affected and unaffected limbs. Preliminary testing on three unimpaired subjects showed that compliant support of the knee provided by the Orthosis explained here results in higher gait speed as well as more natural kinematic profiles for the lower extremities when compared with rigid support of the knee provided by an advanced commercial stance control Orthosis.

  • A quasi-passive compliant stance control Knee-Ankle-Foot Orthosis
    2013 IEEE 13th International Conference on Rehabilitation Robotics (ICORR), 2013
    Co-Authors: Kamran Shamaei, Paul C. Napolitano, Aaron M. Dollar
    Abstract:

    In this paper, we present the design of a novel quasi-passive stance-control Orthosis that implements a natural amount of knee compliance during the weight acceptance phase and potentially the entire stance phase of the gait, and allows for free motion during the rest of the gait. We explain that the unaffected knee behaves close to a linear torsional spring in stance and hypothesize that an assistive device that places a linear spring of appropriate stiffness in parallel with the knee can help restore the natural behavior of the joint in stance. We present the design of a friction-based latching mechanism and a control algorithm that engages the spring in parallel with the knee in stance and disengages it during the swing phase of gait, and explain how this module is implemented into a brace in order to create a novel class of compliant stance control Orthosis. The device is quasi-passive in that a small actuator serves to lock and unlock the spring module, but the device otherwise requires no actuation and very little power, computation, and control to operate.

  • ICORR - A quasi-passive compliant stance control Knee-Ankle-Foot Orthosis
    IEEE ... International Conference on Rehabilitation Robotics : [proceedings], 2013
    Co-Authors: Kamran Shamaei, Paul C. Napolitano, Aaron M. Dollar
    Abstract:

    In this paper, we present the design of a novel quasi-passive stance-control Orthosis that implements a natural amount of knee compliance during the weight acceptance phase and potentially the entire stance phase of the gait, and allows for free motion during the rest of the gait. We explain that the unaffected knee behaves close to a linear torsional spring in stance and hypothesize that an assistive device that places a linear spring of appropriate stiffness in parallel with the knee can help restore the natural behavior of the joint in stance. We present the design of a friction-based latching mechanism and a control algorithm that engages the spring in parallel with the knee in stance and disengages it during the swing phase of gait, and explain how this module is implemented into a brace in order to create a novel class of compliant stance control Orthosis. The device is quasi-passive in that a small actuator serves to lock and unlock the spring module, but the device otherwise requires no actuation and very little power, computation, and control to operate.