scholarly journals Direct Continuous EMG control of a Powered Prosthetic Ankle for Improved Postural Control after Guided Physical Training: a Case Study

2020 ◽  
Author(s):  
Aaron Fleming ◽  
Stephanie Huang ◽  
Elizabeth Buxton ◽  
Frank Hodges ◽  
He (Helen) Huang
Keyword(s):  
Postural Control ◽  
Load Transfer ◽  
Assessment Tool ◽  
Control Method ◽  
Physical Therapist ◽  
Continuous Control ◽  
Rapid Improvement ◽  
Transtibial Amputation ◽  
Prosthetic Joints

AbstractBackgroundDespite the promise of powered lower limb prostheses, the existing control of these modern devices is insufficient to assist many daily activities, such as postural control while lifting weight, that require continuous control of prosthetic joints according to human states and environments. The objective of this case study was to investigate the feasibility and potential of direct, continuous electromyographic (dEMG) control of a powered ankle prosthesis, combined with physical therapist (PT)-guided training, for improved standing postural control in an individual with transtibial amputation.MethodsA powered prosthetic ankle was directly controlled by EMG signals of the residual lateral gastrocnemius and tibialis anterior muscles. The participant with transtibial amputation received 4-week PT-guided training on posture while using the dEMG control of powered ankle. A subset of activities in the mini-BESTest (a clinical balance assessment tool) were used in the training and evaluation protocol. We quantified EMG signals in the bilateral shank muscles, biomechanics that captures postural control and stability, and score for the clinical balance evaluation.ResultsCompared to the participant’s daily passive prosthesis, the dEMG-controlled ankle, combined with the training, yielded improved clinical balance score and reduced compensation from the intact joints. In addition, cross correlation coefficient of bilateral CoP excursions, a metric for quantifying standing postural control, increased to 0.83(±0.07) when using dEMG ankle control, compared with 0.39(±0.29) when using the passive device. Between-limb coordination was also observed as synchronized activation of homologous muscles in the shank. We witnessed rapid improvement in performance on the first day of the training for load transfer tasks, where bilateral CoP synchronization improvement was significantly related to repetition order (R=0.459, p = 0.045). Finally, the participant further improved this performance significantly across training days.ConclusionThis case study showed the feasibility of dEMG control of powered prosthetic ankle by a transtibial amputee after a PT-guided training to assist postural control. This study’s training protocol and dEMG control method that lays the foundation for future study to extend these results through the inclusion of more participants and activities.

scholarly journals Direct continuous electromyographic control of a powered prosthetic ankle for improved postural control after guided physical training: A case study

2021 ◽  
Vol 2 ◽  
Author(s):  
Aaron Fleming ◽  
Stephanie Huang ◽  
Elizabeth Buxton ◽  
Frank Hodges ◽  
He Helen Huang
Keyword(s):  
Postural Control ◽  
Load Transfer ◽  
Center Of Pressure ◽  
Physical Therapist ◽  
Continuous Control ◽  
Rapid Improvement ◽  
Prosthetic Joints ◽  
Evaluation Protocol ◽  
Control Paradigm

Abstract Despite the promise of powered lower limb prostheses, existing controllers do not assist many daily activities that require continuous control of prosthetic joints according to human states and environments. The objective of this case study was to investigate the feasibility of direct, continuous electromyographic (dEMG) control of a powered ankle prosthesis, combined with physical therapist-guided training, for improved standing postural control in an individual with transtibial amputation. Specifically, EMG signals of the residual antagonistic muscles (i.e. lateral gastrocnemius and tibialis anterior) were used to proportionally drive pneumatical artificial muscles to move a prosthetic ankle. Clinical-based activities were used in the training and evaluation protocol of the control paradigm. We quantified the EMG signals in the bilateral shank muscles as well as measures of postural control and stability. Compared to the participant’s daily passive prosthesis, the dEMG-controlled ankle, combined with the training, yielded improved clinical balance scores and reduced compensation from intact joints. Cross-correlation coefficient of bilateral center of pressure excursions, a metric for quantifying standing postural control, increased to .83(±.07) when using dEMG ankle control (passive device: .39(±.29)). We observed synchronized activation of homologous muscles, rapid improvement in performance on the first day of the training for load transfer tasks, and further improvement in performance across training days (p = .006). This case study showed the feasibility of this dEMG control paradigm of a powered prosthetic ankle to assist postural control. This study lays the foundation for future study to extend these results through the inclusion of more participants and activities.

scholarly journals Continuous Control Set Predictive Current Control for Induction Machine

2021 ◽  
Vol 11 (13) ◽  
pp. 6230
Author(s):  
Toni Varga ◽  
Tin Benšić ◽  
Vedrana Jerković Štil ◽  
Marinko Barukčić
Keyword(s):  
Control Method ◽  
Induction Machine ◽  
Current Control ◽  
Continuous Control ◽  
Loop Model ◽  
Voltage Reference ◽  
Control Loop ◽  
Speed Tracking ◽  
Finite Control ◽  
Control Set

A speed tracking control method for induction machine is shown in this paper. The method consists of outer speed control loop and inner current control loop. Model predictive current control method without the need for calculation of the weighing factors is utilized for the inner control loop, which generates a continuous set of voltage reference values that can be modulated and applied by the inverter to the induction machine. Interesting parallels are drawn between the developed method and state feedback principles that helped with the analysis of the stability and controllability. Simple speed and rotor flux estimator is implemented that helps achieve sensorless control. Simulation is conducted and the method shows great performance for speed tracking in a steady state, and during transients as well. Additionally, compared to the finite control set predictive current control, it shows less harmonic content in the generated torque on the rotor shaft.

scholarly journals Plantar load transfer in children: a descriptive study with two pathological case studies

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Alexis Brierty ◽  
Christopher P. Carty ◽  
Claudia Giacomozzi ◽  
Teresa Phillips ◽  
Henry P. J. Walsh ◽  
...  
Keyword(s):  
Case Studies ◽  
Load Transfer ◽  
Descriptive Study ◽  
Transfer Phase ◽  
Gait Symmetry ◽  
Plantar Pressures ◽  
Gait Asymmetry ◽  
Mean Pressure ◽  
Pathological Case

Abstract Background Typical gait is often considered to be highly symmetrical, with gait asymmetries typically associated with pathological gait. Whilst gait symmetry is often expressed in symmetry ratios, measures of symmetry do not provide insight into how these asymmetries affect gait variables. To fully understand changes caused by gait asymmetry, we must first develop a normative database for comparison. Therefore, the aim of this study was to describe normative reference values of regional plantar load and present comparisons with two pathological case studies. Methods A descriptive study of the load transfer of plantar pressures in typically developed children was conducted to develop a baseline for comparison of the effects of gait asymmetry in paediatric clinical populations. Plantar load and 3D kinematic data was collected for 17 typically developed participants with a mean age of 9.4 ± 4.0 years. Two case studies were also included; a 10-year-old male with clubfoot and an 8-year-old female with a flatfoot deformity. Data was analysed using a kinematics-pressure integration technique for anatomical masking into 5 regions of interest; medial and lateral forefoot, midfoot, and medial and lateral hindfoot. Results Clear differences between the two case studies and the typical dataset were seen for the load transfer phase of gait. For case study one, lateral bias was seen in the forefoot of the trailing foot across all variables, as well as increases in contact area, force and mean pressure in the lateral hindfoot of the leading foot. For case study two, the forefoot of the trailing foot produced results very similar to the typical dataset across all variables. In the hindfoot of the leading foot, medial bias presents most notably in the force and mean pressure graphs. Conclusions This study highlights the clinical significance of the load transfer phase of gait, providing meaningful information for intervention planning.

scholarly journals Bioclimatic and Regenerative Design Guidelines for a Circular University Campus in India

2021 ◽  
Vol 13 (15) ◽  
pp. 8238
Author(s):  
Noemi Bakos ◽  
Rosa Schiano-Phan
Keyword(s):  
Construction Industry ◽  
Assessment Tool ◽  
Economic Benefits ◽  
Design Guidelines ◽  
University Campus ◽  
Design Strategies ◽  
Regenerative Design ◽  
Governmental Institutions ◽  
Social Environmental

To transform the negative impacts of buildings on the environment into a positive footprint, a radical shift from the current, linear ‘make-use-dispose’ practice to a closed-loop ‘make-use-return’ system, associated with a circular economy, is necessary. This research aims to demonstrate the possible shift to a circular construction industry by developing the first practical framework with tangible benchmarks for a ‘Circular University Campus’ based on an exemplary case study project, which is a real project development in India. As a first step, a thorough literature review was undertaken to demonstrate the social, environmental and economic benefits of a circular construction industry. As next step, the guideline for a ‘Circular University Campus’ was developed, and its applicability tested on the case study. As final step, the evolved principles were used to establish ‘Project Specific Circular Building Indicators’ for a student residential block and enhance the proposed design through bioclimatic and regenerative design strategies. The building’s performance was evaluated through computational simulations, whole-life carbon analysis and a circular building assessment tool. The results demonstrated the benefits and feasibility of bioclimatic, regenerative building and neighbourhood design and provided practical prototypical case study and guidelines which can be adapted by architects, planners and governmental institutions to other projects, thereby enabling the shift to a restorative, circular construction industry.

scholarly journals A Business Model Framework to Characterize Digital Multisided Platforms

2020 ◽  
Vol 6 (1) ◽  
pp. 10 ◽  
Author(s):  
Marco Ardolino ◽  
Nicola Saccani ◽  
Federico Adrodegari ◽  
Marco Perona
Keyword(s):  
Information And Communication Technologies ◽  
Assessment Tool ◽  
Empirical Studies ◽  
Communication Technologies ◽  
Model Framework ◽  
Recent Developments ◽  
Information And Communication ◽  
Multiple Case ◽  
The One

Businesses grounded upon multisided platforms (MSPs) are found in a growing number of industries, thanks to the recent developments in Internet and digital technologies. Digital MSPs enable multiple interactions among users of different sides through information and communication technologies. The understanding of the characteristics and constituents of MSPs is fragmented along different literature streams. Moreover, very few empirical studies have been carried out to date. In order to fill this gap, this paper presents a three-level framework that describes a digital MSP. The proposed framework is based on literature analysis and multiple case study. On the one hand, the framework can be used to describe MSP as it provides an operationalization of the concept through the identification of specific dimensions, variables and items; on the other hand, it can be used as an assessment tool by practitioners, as exemplified by the three empirical applications presented in this paper.

Continuous control of sampled data systems with robustness against bounded measurement errors

2017 ◽  
Vol 40 (10) ◽  
pp. 3125-3133
Author(s):  
Milad Ghanbari ◽  
Masoud Bahraini ◽  
Mohammad Javad Yazdanpanah
Keyword(s):  
Measurement Errors ◽  
Control Method ◽  
Linear Time ◽  
Continuous Control ◽  
Data Systems ◽  
Sampled Data ◽  
Linear Time Invariant ◽  
Experimental Implementation ◽  
Time Invariant ◽  
Ultimate Bound

This paper considers the design of a generalized hold function to be used for the control of sampled-data systems. The proposed method suggests a continuous controller for sampled data systems. Ultimate boundedness of the proposed method in the presence of bounded measurement errors is also shown for linear and nonlinear systems. In linear time invariant cases, a cost function is suggested for the sake of ultimate bound minimization. In addition, this can answer how we choose a sensor for a real system to get a desired control outcome. Eventually, the effectiveness of the proposed control method is investigated through simulation and experimental implementation.

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