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Adriano A. G. Siqueira - One of the best experts on this subject based on the ideXlab platform.
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feasibility of an optimal emg driven adaptive impedance control applied to an active Knee Orthosis
Robotics and Autonomous Systems, 2019Co-Authors: Guido G Pena, Wilian Dos M. Santos, Leonardo Jose Consoni, Adriano A. G. SiqueiraAbstract:Abstract This paper deals with EMG-driven torque estimation and optimal adaptive impedance control during robot-aided rehabilitation. In this preliminary and feasibility study, the proposed framework was evaluated considering an active Knee Orthosis and only healthy subjects. First, a simplified and optimized musculoskeletal model is used to compute the estimate of user’s torque considering electromyographic (EMG) signals taken from selected muscles acting during flexion and extension movements. The model optimization is performed by comparing the estimated torque from EMG with the torque generated by the inverse dynamics tool of the OpenSim software. As an alternative solution, a multilayer perceptron neural network (NN) is proposed to map the EMG signals to the user’s torque. The proposed approaches are evaluated by a set of healthy subjects wearing the Knee Orthosis and performing a protocol created for user–robot interaction analysis. Then, an EMG-driven adaptive impedance control is proposed to improve the user participation during the rehabilitation session. The approach is based on an optimal solution which considers the position error and the robot assistance level. The experimental results indicate the use of EMG signals is feasible for adaptive control strategies, taking into account the current condition of the user and optimizing the robot assistance.
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design and control of an active Knee Orthosis driven by a rotary series elastic actuator
Control Engineering Practice, 2017Co-Authors: Wilian Dos M. Santos, Glauco A P Caurin, Adriano A. G. SiqueiraAbstract:Abstract Active Orthosis is one of the main research topics in the field of motor recovery. This paper deals with the design and control of an active Knee Orthosis driven by a customized rotary Series Elastic Actuator (SEA). The proposed actuator includes a DC motor, a worm gear and a customized torsion spring. Since the elastic element is the most important component in SEA design, a finite element analysis of the spring is performed to meet the specific requirements for Knee assistance. Torque and impedance control are implemented to ensure secure interaction with the patient and to enable new strategies for rehabilitation. The torque controller, cascaded with an inner motor velocity control loop, is based on H ∞ criterion to achieve good system performance with relation to parametric uncertainties and external disturbances. The impedance control is implemented using a PD position controller in cascade with the torque controller, where the outer position controller determines the desired torque according to position and velocity errors and impedance parameters. A variable impedance control strategy is then implemented to show the possibility to regulate the impedance of the Knee joint during walking. Experiments considering the interaction between the subject and the active Orthosis are performed to evaluate the proposed controllers.
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robust torque control based on h criterion of an active Knee Orthosis
IEEE International Conference on Biomedical Robotics and Biomechatronics, 2014Co-Authors: Wilian Dos M. Santos, Adriano A. G. SiqueiraAbstract:The authors present in this paper a robust torque control of an active Orthosis designed to assist the Knee joint flexion/extension during physical therapy. The Orthosis is driven by a rotary Series Elastic Actuator presented in authors' previous paper. The adopted control strategy is based on H ∞ criterion in order to ensure good system performance even when it is subjected to parametric uncertainties and external disturbances. The controller performance is evaluated through the frequency response function analysis. Experimental results involving the interaction between a subject and the active Knee Orthosis are also presented to show the performance of the developed prototype.
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BioRob - Robust torque control based on H ∞ criterion of an active Knee Orthosis
5th IEEE RAS EMBS International Conference on Biomedical Robotics and Biomechatronics, 2014Co-Authors: Wilian M. Dos Santos, Adriano A. G. SiqueiraAbstract:The authors present in this paper a robust torque control of an active Orthosis designed to assist the Knee joint flexion/extension during physical therapy. The Orthosis is driven by a rotary Series Elastic Actuator presented in authors' previous paper. The adopted control strategy is based on H ∞ criterion in order to ensure good system performance even when it is subjected to parametric uncertainties and external disturbances. The controller performance is evaluated through the frequency response function analysis. Experimental results involving the interaction between a subject and the active Knee Orthosis are also presented to show the performance of the developed prototype.
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Robust torque control based on H∞ criterion of an active Knee Orthosis
5th IEEE RAS EMBS International Conference on Biomedical Robotics and Biomechatronics, 2014Co-Authors: Wilian Dos M. Santos, Adriano A. G. SiqueiraAbstract:The authors present in this paper a robust torque control of an active Orthosis designed to assist the Knee joint flexion/extension during physical therapy. The Orthosis is driven by a rotary Series Elastic Actuator presented in authors' previous paper. The adopted control strategy is based on H∞ criterion in order to ensure good system performance even when it is subjected to parametric uncertainties and external disturbances. The controller performance is evaluated through the frequency response function analysis. Experimental results involving the interaction between a subject and the active Knee Orthosis are also presented to show the performance of the developed prototype.
Wilian Dos M. Santos - One of the best experts on this subject based on the ideXlab platform.
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feasibility of an optimal emg driven adaptive impedance control applied to an active Knee Orthosis
Robotics and Autonomous Systems, 2019Co-Authors: Guido G Pena, Wilian Dos M. Santos, Leonardo Jose Consoni, Adriano A. G. SiqueiraAbstract:Abstract This paper deals with EMG-driven torque estimation and optimal adaptive impedance control during robot-aided rehabilitation. In this preliminary and feasibility study, the proposed framework was evaluated considering an active Knee Orthosis and only healthy subjects. First, a simplified and optimized musculoskeletal model is used to compute the estimate of user’s torque considering electromyographic (EMG) signals taken from selected muscles acting during flexion and extension movements. The model optimization is performed by comparing the estimated torque from EMG with the torque generated by the inverse dynamics tool of the OpenSim software. As an alternative solution, a multilayer perceptron neural network (NN) is proposed to map the EMG signals to the user’s torque. The proposed approaches are evaluated by a set of healthy subjects wearing the Knee Orthosis and performing a protocol created for user–robot interaction analysis. Then, an EMG-driven adaptive impedance control is proposed to improve the user participation during the rehabilitation session. The approach is based on an optimal solution which considers the position error and the robot assistance level. The experimental results indicate the use of EMG signals is feasible for adaptive control strategies, taking into account the current condition of the user and optimizing the robot assistance.
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design and control of an active Knee Orthosis driven by a rotary series elastic actuator
Control Engineering Practice, 2017Co-Authors: Wilian Dos M. Santos, Glauco A P Caurin, Adriano A. G. SiqueiraAbstract:Abstract Active Orthosis is one of the main research topics in the field of motor recovery. This paper deals with the design and control of an active Knee Orthosis driven by a customized rotary Series Elastic Actuator (SEA). The proposed actuator includes a DC motor, a worm gear and a customized torsion spring. Since the elastic element is the most important component in SEA design, a finite element analysis of the spring is performed to meet the specific requirements for Knee assistance. Torque and impedance control are implemented to ensure secure interaction with the patient and to enable new strategies for rehabilitation. The torque controller, cascaded with an inner motor velocity control loop, is based on H ∞ criterion to achieve good system performance with relation to parametric uncertainties and external disturbances. The impedance control is implemented using a PD position controller in cascade with the torque controller, where the outer position controller determines the desired torque according to position and velocity errors and impedance parameters. A variable impedance control strategy is then implemented to show the possibility to regulate the impedance of the Knee joint during walking. Experiments considering the interaction between the subject and the active Orthosis are performed to evaluate the proposed controllers.
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robust torque control based on h criterion of an active Knee Orthosis
IEEE International Conference on Biomedical Robotics and Biomechatronics, 2014Co-Authors: Wilian Dos M. Santos, Adriano A. G. SiqueiraAbstract:The authors present in this paper a robust torque control of an active Orthosis designed to assist the Knee joint flexion/extension during physical therapy. The Orthosis is driven by a rotary Series Elastic Actuator presented in authors' previous paper. The adopted control strategy is based on H ∞ criterion in order to ensure good system performance even when it is subjected to parametric uncertainties and external disturbances. The controller performance is evaluated through the frequency response function analysis. Experimental results involving the interaction between a subject and the active Knee Orthosis are also presented to show the performance of the developed prototype.
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Robust torque control based on H∞ criterion of an active Knee Orthosis
5th IEEE RAS EMBS International Conference on Biomedical Robotics and Biomechatronics, 2014Co-Authors: Wilian Dos M. Santos, Adriano A. G. SiqueiraAbstract:The authors present in this paper a robust torque control of an active Orthosis designed to assist the Knee joint flexion/extension during physical therapy. The Orthosis is driven by a rotary Series Elastic Actuator presented in authors' previous paper. The adopted control strategy is based on H∞ criterion in order to ensure good system performance even when it is subjected to parametric uncertainties and external disturbances. The controller performance is evaluated through the frequency response function analysis. Experimental results involving the interaction between a subject and the active Knee Orthosis are also presented to show the performance of the developed prototype.
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Torque control characterization of a rotary series elastic actuator for Knee rehabilitation
2013 16th International Conference on Advanced Robotics (ICAR), 2013Co-Authors: Wilian Dos M. Santos, Glauco A P Caurin, Adriano A. G. SiqueiraAbstract:This paper presents the evaluation of a rotary Series Elastic Actuator (SEA) designed to assist in flexion/extension of the Knee joint during physical therapy. The proposed device includes a DC motor, a worm gear and a customized torsion spring. Since the elastic element is the most important component in the SEA design, an analysis procedure based on Finite Element Method (FEM) is used in order to meet the specific requirements of Knee assistance. With a total weight of 2.53 kg, it is possible to directly mount the actuator on a Knee Orthosis frame. Torque controller is implemented to ensure secure interaction with the patient and enable new strategies for rehabilitation. The design specifications as well as the controllers performance are verified by experiments.
Constantinos Mavroidis - One of the best experts on this subject based on the ideXlab platform.
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Effects on Normal Gait of a New Active Knee Orthosis for Hemiparetic Gait Retraining
2006 International Conference of the IEEE Engineering in Medicine and Biology Society, 2006Co-Authors: Shyamal Patel, Brian Weinberg, J. Nikitczuk, Constantinos Mavroidis, Benjamin L. Patritti, Ugo Della Croce, Paolo BonatoAbstract:Functional recovery of an impaired gait pattern is a common goal for stroke patients in their rehabilitation. Robotic and mechatronic devices offer a means of facilitating and enhancing gait retraining practices undertaken by clinicians. A new active Knee Orthosis has been developed for gait retraining of stroke patients that may fulfil this role. Since this device is newly developed, it is important to determine its impact on the walking patterns of healthy individuals before exploring its use in gait retraining of stroke patients. The aim of this study was to analyze adaptations in gait mechanics of healthy subjects due to the added mass of the Knee Orthosis while worn uni-laterally and bi-laterally. In our preliminary tests we observed significant deviations from normal gait patterns when the Knee Orthosis was worn uni-laterally. Conversely, minor gait deviations were seen when the Knee Orthosis was worn bi-laterally. This suggests that a bilateral configuration may be more suited for gait retraining purposes
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ICRA - RehAbilitative Knee Orthosis Driven by Electro-Rheological Fluid Based Actuators
Proceedings of the 2005 IEEE International Conference on Robotics and Automation, 2005Co-Authors: J. Nikitczuk, Brian Weinberg, Constantinos MavroidisAbstract:This work aims to demonstrate the feasibility of using Electro-Rheological Fluid (ERF) actuators in orthotics, creating a new breed of rehabilitation devices. ERFs are fluids that experience dramatic changes in rheological properties, such as viscosity or yield stress, in the presence of an electric field. Using the electrically controlled rheological properties of ERFs, compact actuators with an ability to supply high resistive torques in a controllable and tunable fashion, have been developed. This study involves the design, fabrication and testing of an ERF based Knee orthotic device and the innovative ERF actuators it uses. The Knee orthotic is achieved through a standard brace design with a polycentric hinge and gear system. Coupled to this are two Flat-Plate ERF actuators, given that name for their characteristic set of parallel flat plates allowing for actuation of the fluid. A full model describing the field dependant torque output of these actuators is presented along with a full detailed description of the device design. The overall Knee orthotic system is designed to resist up to 25.4% of an average human Knee’s torque abilities and be controlled in real-time. The goal of this work is to provide a much more efficient means of rehabilitation over the average orthotic, while matching the proficiency of rehabilitation machines, all in a smaller, simpler, and more cost efficient design.
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Rehabilitative Knee Orthosis driven by electro-rheological fluid based actuators
Proceedings - IEEE International Conference on Robotics and Automation, 2005Co-Authors: J. Nikitczuk, Brian Weinberg, Constantinos MavroidisAbstract:This work aims to demonstrate the feasibility of using Electro-Rheological Fluid (ERF) actuators in orthotics, creating a new breed of rehabilitation devices. ERFs are fluids that experience dramatic changes in rheological properties, such as viscosity or yield stress, in the presence of an electric field. Using the electrically controlled rheological properties of ERFs, compact actuators with an ability to supply high resistive torques in a controllable and tunable fashion, have been developed. This study involves the design, fabrication and testing of an ERF based Knee orthotic device and the innovative ERF actuators it uses. The Knee orthotic is achieved through a standard brace design with a polycentric hinge and gear system. Coupled to this are two Flat-Plate ERF actuators, given that name for their characteristic set of parallel flat plates allowing for actuation of the fluid. A full model describing the field dependant torque output of these actuators is presented along with a full detailed description of the device design. The overall Knee orthotic system is designed to resist up to 25.4% of an average human Knee’s torque abilities and be controlled in real-time. The goal of this work is to provide a much more efficient means of rehabilitation over the average orthotic, while matching the proficiency of rehabilitation machines, all in a smaller, simpler, and more cost efficient design.
Gertpeter Bruggemann - One of the best experts on this subject based on the ideXlab platform.
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effect of an ankle foot Orthosis on Knee joint mechanics a novel conservative treatment for Knee osteoarthritis
Prosthetics and Orthotics International, 2014Co-Authors: Cynthia Fantini H Pagani, Steffen Willwacher, Rita Benker, Gertpeter BruggemannAbstract:Background:Several conservative treatments for medial Knee osteoarthritis such as Knee Orthosis and laterally wedged insoles have been shown to reduce the load in the medial Knee compartment. However, those treatments also present limitations such as patient compliance and inconsistent results regarding the treatment success.Objective:To analyze the effect of an ankle–foot Orthosis on the Knee adduction moment and Knee joint alignment in the frontal plane in subjects with Knee varus alignment.Study design:Controlled laboratory study, repeated measurements.Methods:In total, 14 healthy subjects with Knee varus alignment were analyzed in five different conditions: without orthotic, with laterally wedged insoles, and with an ankle–foot Orthosis in three different adjustments. Three-dimensional kinetic and kinematic data were collected during gait analysis.Results:Significant decreases in Knee adduction moment, Knee lever arm, and joint alignment in the frontal plane were observed with the ankle–foot Orthosis ...
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Influence of a valgus Knee brace on muscle activation and co-contraction in patients with medial Knee osteoarthritis
Journal of Electromyography and Kinesiology, 2012Co-Authors: Cynthia H. Fantini Pagani, Steffen Willwacher, Barbara Kleis, Gertpeter BruggemannAbstract:Abstract The purpose of this study was to analyse the effect of a valgus Knee Orthosis designed for patients with Knee osteoarthritis on the electromyographic activity (EMG) of seven muscles of the lower limb during gait. Twelve patients with medial Knee osteoarthritis walked on a treadmill in three different conditions: without Orthosis, with a Knee Orthosis in 4° valgus adjustment and with an Orthosis in a neutral flexible adjustment. Root-mean-square (RMS) was analysed in each condition during a 150 ms pre-activation phase and during the stance phase of gait, which was divided in four sub-phases. In addition, co-contraction ratios (CCRs) were calculated between extensor/flexor, medial/lateral muscles and between agonist and antagonist muscle pairs. Significant decreases in muscle activity and CCRs were observed with the use of the Knee Orthosis in both adjustments compared to the condition without Orthosis. Using the valgus brace, medial/lateral CCR decreased significantly during the late stance and the flexor/extensor CCR decreased significantly during the loading phase and late stance. Decreases of muscle pairs CCRs were observed with the neutral flexible adjustment. The results support the theory of a possible beneficial effect of Knee braces in reducing Knee loading by decreasing muscle activation and co-contraction levels, which could contribute to decelerate disease progression in patients with Knee osteoarthritis.
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Kinetic and kinematic changes with the use of valgus Knee brace and lateral wedge insoles in patients with medial Knee osteoarthritis.
Journal of Orthopaedic Research, 2011Co-Authors: Cynthia H. Fantini Pagani, Maren Hinrichs, Gertpeter BruggemannAbstract:The effect of a valgus Knee brace and a lateral wedged insole on Knee and ankle kinematics and kinetics was evaluated in ten patients with medial Knee osteoarthritis (OA). The Knee Orthosis was tested in two valgus adjustments (4° and 8°), and the laterally wedged insole was fabricated with an inclination of 4°. A motion capture system and force platforms were used for data collection and joint moments were calculated using inverse dynamics. The valgus moment applied by the Orthosis was also measured using a strain gauge implemented in the Orthosis' rotational axis. For the second peak Knee adduction moment, decreases of 18%, 21%, and 7% were observed between baseline and test conditions for the Orthosis in 4° valgus, in 8° valgus, and insole, respectively. Similar decreases were observed for Knee lever arm in the frontal plane. Knee adduction angular impulse decreased 14%, 18%, and 7% from baseline to conditions for the Orthosis in 4° valgus, in 8° valgus, and insole, respectively. Knee angle in the frontal plane reached a more valgus position during gait using the valgus Knee brace. The valgus moment applied by the Orthosis with 8° valgus adjustment was 30% higher than with 4° valgus adjustment. The valgus Knee Orthosis was more effective than the laterally wedged insole in reducing Knee adduction moment in patients with medial Knee OA.
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short term effects of a dedicated Knee Orthosis on Knee adduction moment pain and function in patients with osteoarthritis
Archives of Physical Medicine and Rehabilitation, 2010Co-Authors: Cynthia Fantini H Pagani, Caroline Bohle, Wolfgang Potthast, Gertpeter BruggemannAbstract:Abstract Fantini Pagani CH, Bohle C, Potthast W, Bruggemann G-P. Short-term effects of a dedicated Knee Orthosis on Knee adduction moment, pain, and function in patients with osteoarthritis. Objective To analyze Knee joint loading, subjective pain relief, and improvements in function in patients with osteoarthritis (OA) with the use of 2 Orthosis adjustments. Design Patients were tested under 3 different conditions (without Orthosis, Orthosis at 4° valgus, and a neutral very flexible adjustment) in a crossover trial. Setting University gait analysis laboratory with 3-dimensional motion analysis and force platforms. Participants Patients (N=11) with a clinical and radiographic diagnosis of unilateral OA in the medial Knee compartment. Interventions Patients wore a Knee Orthosis designed to unload the medial Knee compartment for 4 weeks in 2 different adjustments (2 weeks in each adjustment). Main Outcome Measures Net Knee adduction moment and net Knee adduction angular impulse during the stance phase were analyzed by using inverse dynamics. Subjective pain relief, stiffness, and function improvement were evaluated using a questionnaire (Western Ontario and McMaster Universities Osteoarthritis Index). A 6-minute walk test and stair-climbing test also were performed. Results Both Orthosis adjustments induced subjective pain relief and improvement in function compared with the condition without Orthosis. Knee adduction moment was significantly decreased with both adjustments, whereas the decrease observed with the 4° valgus adjustment was significantly greater than the flexible adjustment (25% vs 12.5%). Compared with the condition without Orthosis, changes in Knee adduction angular impulse of 29% and 15% were found with 4° valgus and the neutral flexible Orthosis, respectively. Time required for the stair-climbing activity was significantly decreased using the Orthosis in 4° valgus adjustment compared with the condition without Orthosis. No significant differences were observed among conditions during the 6-minute walk test. Conclusions Both Orthosis adjustments were effective in decreasing symptoms; however, a decrease in Knee loading was more effective using the 4° valgus adjustment, which could contribute to avoidance of disease progression.
J. Nikitczuk - One of the best experts on this subject based on the ideXlab platform.
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Effects on Normal Gait of a New Active Knee Orthosis for Hemiparetic Gait Retraining
2006 International Conference of the IEEE Engineering in Medicine and Biology Society, 2006Co-Authors: Shyamal Patel, Brian Weinberg, J. Nikitczuk, Constantinos Mavroidis, Benjamin L. Patritti, Ugo Della Croce, Paolo BonatoAbstract:Functional recovery of an impaired gait pattern is a common goal for stroke patients in their rehabilitation. Robotic and mechatronic devices offer a means of facilitating and enhancing gait retraining practices undertaken by clinicians. A new active Knee Orthosis has been developed for gait retraining of stroke patients that may fulfil this role. Since this device is newly developed, it is important to determine its impact on the walking patterns of healthy individuals before exploring its use in gait retraining of stroke patients. The aim of this study was to analyze adaptations in gait mechanics of healthy subjects due to the added mass of the Knee Orthosis while worn uni-laterally and bi-laterally. In our preliminary tests we observed significant deviations from normal gait patterns when the Knee Orthosis was worn uni-laterally. Conversely, minor gait deviations were seen when the Knee Orthosis was worn bi-laterally. This suggests that a bilateral configuration may be more suited for gait retraining purposes
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ICRA - RehAbilitative Knee Orthosis Driven by Electro-Rheological Fluid Based Actuators
Proceedings of the 2005 IEEE International Conference on Robotics and Automation, 2005Co-Authors: J. Nikitczuk, Brian Weinberg, Constantinos MavroidisAbstract:This work aims to demonstrate the feasibility of using Electro-Rheological Fluid (ERF) actuators in orthotics, creating a new breed of rehabilitation devices. ERFs are fluids that experience dramatic changes in rheological properties, such as viscosity or yield stress, in the presence of an electric field. Using the electrically controlled rheological properties of ERFs, compact actuators with an ability to supply high resistive torques in a controllable and tunable fashion, have been developed. This study involves the design, fabrication and testing of an ERF based Knee orthotic device and the innovative ERF actuators it uses. The Knee orthotic is achieved through a standard brace design with a polycentric hinge and gear system. Coupled to this are two Flat-Plate ERF actuators, given that name for their characteristic set of parallel flat plates allowing for actuation of the fluid. A full model describing the field dependant torque output of these actuators is presented along with a full detailed description of the device design. The overall Knee orthotic system is designed to resist up to 25.4% of an average human Knee’s torque abilities and be controlled in real-time. The goal of this work is to provide a much more efficient means of rehabilitation over the average orthotic, while matching the proficiency of rehabilitation machines, all in a smaller, simpler, and more cost efficient design.
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Rehabilitative Knee Orthosis driven by electro-rheological fluid based actuators
Proceedings - IEEE International Conference on Robotics and Automation, 2005Co-Authors: J. Nikitczuk, Brian Weinberg, Constantinos MavroidisAbstract:This work aims to demonstrate the feasibility of using Electro-Rheological Fluid (ERF) actuators in orthotics, creating a new breed of rehabilitation devices. ERFs are fluids that experience dramatic changes in rheological properties, such as viscosity or yield stress, in the presence of an electric field. Using the electrically controlled rheological properties of ERFs, compact actuators with an ability to supply high resistive torques in a controllable and tunable fashion, have been developed. This study involves the design, fabrication and testing of an ERF based Knee orthotic device and the innovative ERF actuators it uses. The Knee orthotic is achieved through a standard brace design with a polycentric hinge and gear system. Coupled to this are two Flat-Plate ERF actuators, given that name for their characteristic set of parallel flat plates allowing for actuation of the fluid. A full model describing the field dependant torque output of these actuators is presented along with a full detailed description of the device design. The overall Knee orthotic system is designed to resist up to 25.4% of an average human Knee’s torque abilities and be controlled in real-time. The goal of this work is to provide a much more efficient means of rehabilitation over the average orthotic, while matching the proficiency of rehabilitation machines, all in a smaller, simpler, and more cost efficient design.