Rehabilitation Scenarios Research Articles

A Pneumatic Soft Exoskeleton System Based on Segmented Composite Proprioceptive Bending Actuators for Hand Rehabilitation.

Soft pneumatic actuators/robotics have received significant interest in the medical and health fields, due to their intrinsic elasticity and simple control strategies for enabling desired interactions. However, current soft hand pneumatic exoskeletons often exhibit uniform deformation, mismatch the profile of the interacting objects, and seldom quantify the assistive effects during activities of daily life (ADL), such as extension angle and predicted joint stiffness. The lack of quantification poses challenges to the effective and sustainable advancement of rehabilitation technology. This paper introduces the design, modeling, and testing of pneumatic bioinspired segmented composite proprioceptive bending actuators (SCPBAs) for hand rehabilitation in ADL tasks. Inspired by human finger anatomy, the actuator's soft-joint-rigid-bone segmented structure provides a superior fit compared to continuous structures in traditional fiber-reinforced actuators (FRAs). A quasi-static model is established to predict the bending angles based on geometric parameters. Quantitative evaluations of predicted joint stiffness and extension angle utilizing proprioceptive bending are performed. Additionally, a soft under-actuated hand exoskeleton equipped with SCPBAs demonstrates their potential in ADL rehabilitation scenarios.

Cost-benefit analysis of working with recovery in river management using Marxan

With the impact and cost of continued river degradation and climate change-induced extreme rainfall and floods, there is growing urgency to achieve and maintain good river health to meet global sustainable development goals. Up-scaling and working with nature-based solutions at regional, catchment and fluvial corridor scales is critical. One way to achieve this is to work within a recovery-enhanced approach to river rehabilitation, incorporating processes of geomorphic and vegetative recovery to build fluvial corridors in areas where they have become fragmented. Geomorphologically-informed cost-benefit analysis has not previously been applied in a riverine or riparian context, at the catchment or regional scale needed. We applied Marxan in a novel manner to undertake the first cost-benefit analysis for geomorphologically-informed rehabilitation of river systems. We estimated that to rehabilitate 75,500 km of streams in coastal catchments of NSW will cost $8.2 billion, comparing favourably to recent single flood event insurance losses, and projected future losses. We developed Marxan scenarios based on three broad approaches to river management: ad hoc and reactive, working with recovery and corridors, across current and future time periods. We found there are considerable current and flow-on future financial and non-financial benefits, and lower initial total and per-hectare rehabilitation costs, by fully adopting working with recovery or corridors approaches and moving away from the ad hoc and reactive approaches which dominate current practice. Implementing targeted rehabilitation based on a rolling sequence over time of corridors scenarios provides optimal holistic solutions to improve geomorphic condition and enhance recovery potential at landscape-scale. Our study demonstrates the use of Marxan as an accessible tool to address prioritisation complexity, and to run and cost landscape-scale rehabilitation scenarios over time. Our study also demonstrates the positive offsite feedbacks that occur through multiplier effects, as recovery occurs, and corridors are built. Geomorphologically-informed decision making becomes more robust, transparent, cost-effective, consistent across catchments, and adaptive to local situations and evolving river management priorities.

Optimizing Real-Time MI-BCI Performance in Post-Stroke Patients: Impact of Time Window Duration on Classification Accuracy and Responsiveness.

Brain-computer interfaces (BCIs) are promising tools for motor neurorehabilitation. Achieving a balance between classification accuracy and system responsiveness is crucial for real-time applications. This study aimed to assess how the duration of time windows affects performance, specifically classification accuracy and the false positive rate, to optimize the temporal parameters of MI-BCI systems. We investigated the impact of time window duration on classification accuracy and false positive rate, employing Linear Discriminant Analysis (LDA), Multilayer Perceptron (MLP), and Support Vector Machine (SVM) on data acquired from six post-stroke patients and on the external BCI IVa dataset. EEG signals were recorded and processed using the Common Spatial Patterns (CSP) algorithm for feature extraction. Our results indicate that longer time windows generally enhance classification accuracy and reduce false positives across all classifiers, with LDA performing the best. However, to maintain the real-time responsiveness, crucial for practical applications, a balance must be struck. The results suggest an optimal time window of 1-2 s, offering a trade-off between classification performance and excessive delay to guarantee the system responsiveness. These findings underscore the importance of temporal optimization in MI-BCI systems to improve usability in real rehabilitation scenarios.

Natural Water Sources and Small-Scale Non-Artisanal Andesite Mining: Scenario Analysis of Post-Mining Land Interventions Using System Dynamics

Small-scale open-pit, non-artisanal mining of low-value ores is an understudied practice despite its widespread occurrence and potential impact on freshwater resources due to mining-induced land-use/cover changes (LUCCs). This research investigates the long-term impacts of andesite mining in Pasuruan, Indonesia, on the Umbulan Spring’s water discharge within its watershed. System Dynamics (SD) modeling captures the systemic and systematic impact of mining-induced LUCCs on discharge volumes and groundwater recharge. Agricultural and reservoir-based land reclamation scenarios then reveal post-mining temporal dynamics. The no-mining scenario sees the spring’s discharge consistently decrease until an inflection point in 2032. With mining expansion, reductions accelerate by ~1.44 million tons over two decades, or 65.31 thousand tons annually. LUCCs also decrease groundwater recharge by ~2.48 million tons via increased surface runoff. Proposed post-mining land interventions over reclaimed mining areas influence water volumes differently. Reservoirs on reclaimed land lead to ~822.14 million extra tons of discharge, 2.75 times higher than the agricultural scenario. Moreover, reservoirs can restore original recharge levels by 2039, while agriculture only reduces the mining impact by 28.64% on average. These findings reveal that small-scale non-artisanal andesite mining can disrupt regional hydrology despite modest operating scales. Thus, evidence-based guidelines are needed for permitting such mines based on environmental risk and site water budgets. Policy options include discharge or aquifer recharge caps tailored to small-scale andesite mines. The varied outputs of rehabilitation scenarios also highlight evaluating combined land and water management interventions. With agriculture alone proving insufficient, optimized mixes of revegetation and water harvesting require further exploration.

Extreme weight conditions impact on the relationship between risky decision-making and interoception

Anorexia nervosa (AN) and obesity (OB) lie on the two ends of the broad spectrum of extreme weight conditions (EWC). Both disorders entail the constant risk to one's body integrity. Importantly, risk-taking is supported by internal signals, the perception of which is typically distorted in EWC. In this study, we sought to characterize in EWC: (i) risky decision-making by contrasting situations in which people process bodies or neutral objects and (ii) the relationship between interoceptive ability and risky decision-making. In a between-subject design, participants with AN restricting type, participants with class 2 OB, and two groups of matched healthy controls (HC) (total N = 160) were administered either the Balloon Analogue Risk Task (BART) or a modified version of it by using a body-related stimulus as a cue in the place of the balloon. Moreover, we collected a measure of interoceptive sensibility and a measure of interoceptive accuracy. Results showed that, when analysing the global population as a continuum based on the BMI, the risk propensity decreased as a function of increased BMI, only for the task involving a body-related stimulus. Moreover, while HC risk propensity toward a body-related stimulus correlated with interoceptive sensibility, such correlation was absent in participants with AN. Individuals with OB, on the opposite pole, showed mixed interaction between interoception and risky decision-making in both tasks. These findings add one more tile to understanding these complex pathologies in the EWC spectrum, opening up future differential rehabilitation scenarios.

Trajectory Synthesis and Linkage Design of Single-Degree-of-Freedom Finger Rehabilitation Device

For injured and after-stroke patients who temporarily lose their hand’s grasping abilities, assisting them in regaining their index finger mobility is very important in the rehabilitation process. In this paper, a finger rehabilitation device based on one degree-of-freedom (DOF) linkage mechanism is designed, aiming to lead the index finger through the flexion–extension trajectory during grasping tasks. Two types of one-DOF mechanisms, a four-bar linkage and a Watt-I six-bar linkage, are synthesized for the task trajectory. Various algorithms such as PSO, GA, and GA–BFGS are adopted and compared for the synthesis of these two types of mechanisms, among which the Watt-I six-bar linkage obtained with GA–BFGS shows the optimal performance in accuracy. Clinical biomechanical data are utilized to perform static analyses of the mechanisms, and the feasibility of the Watt-I six-bar linkage models is tested, compared, and demonstrated. Finally, the prototype of the six-bar linkage as well as a wearable exoskeleton finger rehabilitation device are designed to show how they are applied in the finger rehabilitation scenario.

Studying the Structure of the Road Pavement and Specifying the Repair Method

Studying the structural condition of road pavement is essential for making effective decisions about the type of maintenance or rehabilitation that will be carried out on a pavement section. Reliable quantitative assessment of the volume of necessary repairs will ensure the performance characteristics and durability throughout the entire service life at minimal cost. This article presents detailed results from Falling Weight Deflectometer (FWD) and Ground Penetrating Radar (GPR) studies. In addition, an analysis of these results and recommendations for strengthening the road pavement for the Sh-176 “Sighnaghi-Saint Nino Monastery” road to develop rehabilitation and maintenance scenarios. FWD results combined with road pavement layer thickness and traffic load information to determine residual service life and necessary treatment type. Thus, using the nonlinear theory of layered halfspace elasticity, pavement structure analyzed in the same way as other civil engineering structures.

Reducing Hand Kinematics by Introducing Grasp-Oriented Intra-Finger Dependencies

Loss of hand functions, often manifesting in the form of weakness or spasticity from conditions like stroke or multiple sclerosis, poses challenges in performing activities of daily living (ADLs). The broad area of rehabilitation robotics provides the tools and knowledge necessary for implementing efficient restorative therapies. These therapies aim to improve hand functionality with minimal therapist intervention. However, the human hand evolved for various precision and power gripping tasks, with its intricate anatomy featuring a large number of degrees of freedom—up to 31—which hinder its modeling in many rehabilitation scenarios. In the process of designing prosthetic devices, instrumented gloves, and rehabilitation devices, there is a clear need to obtain simplified rehabilitation-oriented hand models without compromising their representativeness across the population. This is where the concept of kinematic reduction, focusing on specific grasps, becomes essential. Thus, the objective of this study is to uncover the intra-finger dependencies during finger flexion/extension by analyzing a comprehensive database containing recorded trajectories for 23 different functional movements related to ADLs, involving 77 test subjects. The initial phase involves data wrangling, followed by correlation analysis aimed at selecting 116 dependency-movement relationships across all grasps. A regularized generalized linear model is then applied to select uncorrelated predictors, while a linear mixed-effect model, with reductions based on both predictor significance and effect size, is used for modeling the dependencies. As a final step, agglomerative clustering of models is performed to further facilitate flexibility in tradeoffs in hand model accuracy/reduction, allowing the modeling of finger flexion extensions using 5–15 degrees of freedom only.

A Versatile Embedded Platform for Implementation of Bio Cooperative Control in Upper-Limb Neuro Motor Rehabilitation Scenario ,

This paper presents a versatile embedded platform designed for the implementation of bio-cooperative control in upper-limb neuromotor rehabilitation scenarios. With an increasing demand for effective rehabilitation techniques, particularly in cases of upper-limb impairments, there is a growing need for innovative technologies that can seamlessly integrate with existing rehabilitation protocols. The proposed platform leverages embedded systems technology to offer real-time feedback and control, facilitating personalized and interactive rehabilitation exercises. By incorporating bio- cooperative control strategies, which enable seamless collaboration between the user and the rehabilitation system, the platform aims to enhance engagement and effectiveness of rehabilitation sessions. The platform's versatility allows it to be easily customized and adapted to different rehabilitation scenarios, making it a promising tool for improving outcomes in upper-limb neuromotor rehabilitation.

Sex differences in the physiological responses to cardiac rehabilitation: a systematic review

BackgroundHeart disease is one of the leading causes of death in Canada. Many heart disease patients are referred for cardiac rehabilitation, a multidisciplinary outpatient program often consisting of exercise training. Cardiac rehabilitation has been proven to be a successful secondary preventative measure in reducing mortality and improving overall health in heart disease patients, and its completion is important for both sexes as there is growing evidence that women benefit as much as men, if not more, with regard to mortality. It is important to note that previous studies have shown that healthy men and women respond differently to aerobic and resistance training, possibly due to hormones, body composition, autonomic and/or cardiovascular differences. However, evaluating sex differences in the efficacy of standard cardiac rehabilitation programs has not yet been fully explored with many studies investigating clinical or anthropometric data but not physiological outcomes. This systematic review aimed to investigate physiological differences in male and female heart disease patients after cardiac rehabilitation. The inclusion criteria were purposefully broad to encompass many cardiac rehabilitation scenarios, many cardiac disease states, and various program lengths and intensities with the intention of highlighting strengths and weaknesses of the current body of literature.MethodsTo conduct a synthesis without meta-analysis, a search strategy was generated to examine the relationships between heart disease patients, a supervised exercise program, physiological outcomes, and sex differences. The review was registered (Prospero: CRD42021251614) and the following databases were searched from inception to 19 December 2023: APA PsycInfo (Ovid), CINAHL Complete (EBSCOhost), Embase (Ovid), Emcare Nursing (Ovid), Medline All (Ovid; includes PubMed non-Medline), and Web of Science Core Collection. Eighty-eight studies pertaining to fitness, metabolism, body composition, respiratory function, cardiac function and C-reactive protein underwent data extraction.Results and conclusionsImportantly, this review suggests that men and women respond similarly to a wide-range of cardiac rehabilitation programs in most physiological variables. However, many studies discussing maximal oxygen consumption, functional capacity, six-minute walk distances, and grip strength suggest that men benefit more. Further research is required to address certain limitations, such as appropriate statistical methods and type/intensity of exercise interventions.

Non-photorealistic rendering as a feedback strategy in virtual reality for rehabilitation

Virtual reality (VR) rehabilitation has been proven to be a very promising method to increase the focus and attention of patients by immersing them in a virtual world, and through that, improve the effectiveness of the rehabilitation. One of the biggest challenges in designing VR Rehabilitation exercises is in choosing feedback strategies that guide the patient and give the appropriate success/failure indicators, without breaking their sense of immersion. A new strategy for feedback is proposed, using non-photorealistic rendering (NPR) to highlight important parts of the exercise the patient needs to focus on and fade out parts of the scene that are not relevant. This strategy is implemented into an authoring tool that allows rehabilitators specifying feedback strategies while creating exercise profiles. The NPR feedback can be configured in many ways, using different NPR schemes for different layers of the exercise environment such as the background environment, the non-interactive exercise objects, and the interactive exercise objects. The main features of the system including the support for universal render pipeline, camera stacking, and stereoscopic rendering are evaluated in a testing scenario. Performance tests regarding memory usage and supported frames per second are also considered. In addition, a group of rehabilitators evaluated the system usability. The proposed system meets all the requirements to apply NPR effect in VR scenarios and solves all the limitations with regard to technical function and image quality. In addition, the system performance has been shown to meet the targets for low-cost hardware. Regarding authoring tool usability rehabilitators agree that is easy to use and a valuable tool for rehabilitation scenarios. NPR schemes can be integrated into VR rehabilitation scenarios achieving the same image quality as non-VR visualizations with only a small impact on the frame rate. NPR schemes are a good visual feedback alternative.

Assessment of the Erosion and Outflow Intensity in the Rif Region under Different Land Use and Land Cover Scenarios

The port of Tangier Med is essential due to its strategic location, as it is an important trading center linking Europe, North America, and Africa. However, the increased rates of downstream sediment transportation put pressure on the sustainable future of the port. Thus, assessing the existing erosion rates and future improvement scenarios is imperative for planning sustainable management at the catchment level. We utilize the Erosion Potential Model (EPM) combined with the Intensity of Erosion and Outflow (IntErO) algorithm to assess the erosion and outflow intensity and to distinguish the sediment-producing areas in the R’mel watershed. The port’s proximity at the bottom of the slope opposite the R’mel Dam is relevant in this context. Initial results show an average erosion rate of 13 t/ha/year. Quarry operations were identified as the primary sediment source, as indicated by the factors contributing to erosion. The qualitative PAP/RAC (Priority Actions Program/Regional Activity Center) model was used to assess the development trends in the watershed, confirming a clear tendency toward irreversible degradation in the quarry areas. Considering that the mined carbonate lithology represents 23.77% of the total area of the catchment, the situation in the region could deteriorate if quarry operations continue. The simulation of quarry rehabilitation scenarios through land use and land cover change (LULC) with IntErO shows that reforestation of quarries can significantly reduce erosion rates (4.78 t/ha/year) compared to their conversion to agricultural land. This study underlines the effectiveness of IntErO, based on the EPM model, in quickly and effectively mapping and quantifying water erosion.

Tidal asymmetry and mud transport in Oualidia Lagoon: Actual conditions in 2012 and rehabilitation scenarios

Oyster aquaculture in Oualidia Lagoon, Morocco, has suffered from poor water quality and water confinement in its upstream region. Tidal asymmetry (TA) has been suggested as a possible cause, and a sediment trap was dredged in 2011 to mitigate this condition. This study addresses TA in the lagoon using field measurements and numerical modeling in the presence of the sediment trap. Results indicate that the lagoon is flood-dominated mostly in its upstream end, where frictional forces exceed inertia accelerations during the tidal cycle and fine sediments settle on the tidal flats and inside the sediment trap. However, this study shows that a large mass of suspended sediments is exported to the ocean, which is contrary to expectations in flood-dominated lagoons. Defining the sediment trap as the rehabilitation scenario S1, the impacts of three additional scenarios on TA are examined. These are scenario S2 (dredging the upstream section of the main channel), scenario S3 (dredging the channels surrounding the flood delta near the inlets), and scenario S4 (raising the ocean level by 0.5 m following climate change predictions). Results show that none of these scenarios modify the tidal flood dominance in the lagoon, although scenarios S2 and S4 decrease its intensity in the upstream region. Nevertheless, all scenarios still contribute to a significant export of sediments to the ocean. This suggests that lagoon management activities should not rely on tidal asymmetry analyses that normally predict upstream sediment transport in flood-dominated lagoons.

A multiobjective optimization approach for wastewater network long-term rehabilitation planning: a case study

Abstract During the last decades, municipalities have increasingly invested in new approaches for rehabilitating sewerage networks. With the increasing number of rehabilitation techniques, objectives and constraints, the number of rehabilitation scenarios rises exponentially. This article proposes an asset management approach to create long-term rehabilitation plans where different budget allocations for rehabilitation techniques are considered every year depending on performance and cost indicators. It builds long-term strategies through multiobjective black-box optimization where the impact of the budget allocations over the network life cycle is part of the decision process. It employs a pipe deterioration model based on Markov chains whose transition matrices are estimated by survival curves for different pipe cohorts. The proposed approach seeks to determine the appropriate investment (CAPEX) and operational expenses (OPEX) levels in the coming decades. It was tested with real-world data from a sewerage network in Sofia, Bulgaria, and the results show that it provides efficient long-term rehabilitation plans.

Gait Sensing and Haptic Feedback Using an Inflatable Soft Haptic Sensor

Abstract Collecting gait data and providing haptic feedback are essential for the safety and efficiency of robot-based rehabilitation. However, readily available devices that can perform both are scarce. This work presents a novel method for mutual sensing and haptic feedback, through the development of an inflatable soft haptic sensor (ISHASE). The design, modeling, and characterization of ISHASE are discussed. Four ISHASEs are embedded in the insole of a shoe to measure ground reaction forces and provide haptic feedback. Four participants were recruited to evaluate the performance of ISHASE as a sensor and haptic device. Experimental results indicate that ISHASE can accurately estimate user’s ground reaction forces while walking, with a maximum and a minimum accuracy of 91% and 85%, respectively. Haptic feedback was delivered to four different locations under the foot, and users could identify the location with an average 92% accuracy. A case study that exemplifies a rehabilitation scenario is presented to demonstrate ISHASE’s usefulness for mutual sensing and haptic feedback.

Advancements in Active Dynamic Orthoses: A Comprehensive Review of Hand Muscle Rehabilitation Strategies

In the field of rehabilitation, nuanced interventions are imperative due to the intricate anatomical complexity and versatile functionality of the human hand. From fractures and tendon injuries to neurological disorders and congenital anomalies, hand orthoses, both static and active, serve as crucial adjuncts to conventional therapeutic approaches. Active hand orthoses play a pivotal role in coordinating rehabilitation efforts, offering tailored support, dynamic control, and therapeutic facilitation. This review paper explored the scientific landscape surrounding active hand orthoses, consolidating evidence-based insights into their design, functionality, and clinical applications. The paper offered an in-depth examination of various studies, showcasing pioneering designs like hinged gloves, electro-hydraulic orthoses, and those integrating virtual reality exercises. The biomechanical principles underlying the effectiveness of active hand orthoses were emphasized, highlighting their role in optimizing outcomes across different rehabilitation scenarios. The review also covered advancements in electroencephalography (EEG)-controlled orthoses and myoelectric technology, illustrating the diverse applications for hand rehabilitation. By synthesizing current knowledge, this review established a foundation for further research and advancements in the ever-evolving field of active hand orthoses.

Blind people can actively manipulate virtual objects with a novel tactile device

Frequently in rehabilitation, visually impaired persons are passive agents of exercises with fixed environmental constraints. In fact, a printed tactile map, i.e. a particular picture with a specific spatial arrangement, can usually not be edited. Interaction with map content, instead, facilitates the learning of spatial skills because it exploits mental imagery, manipulation and strategic planning simultaneously. However, it has rarely been applied to maps, mainly because of technological limitations. This study aims to understand if visually impaired people can autonomously build objects that are completely virtual. Specifically, we investigated if a group of twelve blind persons, with a wide age range, could exploit mental imagery to interact with virtual content and actively manipulate it by means of a haptic device. The device is mouse-shaped and designed to jointly perceive, with one finger only, local tactile height and inclination cues of arbitrary scalar fields. Spatial information can be mentally constructed by integrating local tactile cues, given by the device, with global proprioceptive cues, given by hand and arm motion. The experiment consisted of a bi-manual task, in which one hand explored some basic virtual objects and the other hand acted on a keyboard to change the position of one object in real-time. The goal was to merge basic objects into more complex objects, like a puzzle. The experiment spanned different resolutions of the tactile information. We measured task accuracy, efficiency, usability and execution time. The average accuracy in solving the puzzle was 90.5%. Importantly, accuracy was linearly predicted by efficiency, measured as the number of moves needed to solve the task. Subjective parameters linked to usability and spatial resolutions did not predict accuracy; gender modulated the execution time, with men being faster than women. Overall, we show that building purely virtual tactile objects is possible in absence of vision and that the process is measurable and achievable in partial autonomy. Introducing virtual tactile graphics in rehabilitation protocols could facilitate the stimulation of mental imagery, a basic element for the ability to orient in space. The behavioural variable introduced in the current study can be calculated after each trial and therefore could be used to automatically measure and tailor protocols to specific user needs. In perspective, our experimental setup can inspire remote rehabilitation scenarios for visually impaired people.

Rosetta Branch Conveyance Capacity and Rehabilitation Scenarios

River channels alter their planform, geometric shape and extent over time due to frequent morphodynamic changes and human interventions. Rosetta Branch of the Nile River experiences a reduction in the maximum conveyance capacity due to human encroachments and a prevailing morphological deposition trend. The main objective of this research is to propose rehabilitation scenarios to increase the maximum conveyance capacity of the branch to convey high-flow discharges for future agricultural mega projects irrigation. A two-dimensional numerical model was used to evaluate the morphological and hydrological changes that occurred during a period of 17 years from the year 2003 to 2020 using different flow scenarios. The results show a prevailing deposition trend along the branch with a total volume of 12.5 million m3 leading to a reduction in the maximum conveyance capacity by a percentage of 25%. Three rehabilitation scenarios were proposed to increase the maximum conveyance capacity. It is concluded that the second rehabilitation scenario is the optimum as it increased the maximum conveyance capacity by 66% and reduced inundated land area by 34%.

Identification of fractional Hammerstein model for electrical stimulated muscle: An application of fuzzy-weighted differential evolution

Fractional order representations model complex systems with less parameters, improved accuracy and enhanced robustness in control systems but the system identification of fractional order systems is highly complicated and challenging task because of substantial nonlinearity of the input, unknown linear/nonlinear parameters of the blocks, and unknown fractional order. In this paper, parameter estimation technique is proposed based on fuzzy-weighted differential evolution algorithm for fractional electrically stimulated muscle models, which is generalization of fractional Hammerstein controlled autoregressive model vital for rehabilitation of spinal cord injury (SCI) patients. The system identification problem of fractional electrically stimulated muscle models (FESMMs) is formulated via mean square error approximation between the true and estimated response of FESMMs. The parameters of FESMMs are identified by employing fuzzy weighted differential evolution algorithm optimization knacks of with polynomial, cubic spline and sigmoidal input nonlinearities on various noise variances in the system dynamics. Comparison of results from actual to calculated responses indicates closeness up to 4 decimal places of accuracy for FESMM with polynomial type nonlinearity, up to 6 decimal places for FESMM with sigmoidal type kernel, and up to 5 decimal for FESMM with cubic spline type nonlinearity for different low and high signal to noise scenarios i.e., σ2=0.0022,0.022,0.22, which verify the precision, efficacy, stability and reliability of the fuzzy weighted differential evolution algorithm for system identification of FESMMs in rehabilitation scenarios of SCI.

Human‐centered active torque‐based AAN impedance control for lower limb patient‐exoskeleton coupling system in the rehabilitation

AbstractThis article presents a human‐centered active torque‐based assist‐as‐needed (ATAAN) impedance control for lower limb patient‐exoskeleton coupling system (LLPECS), which considers the coupling effects (e.g., elastic connections, human soft tissues). The proposed double loop structure controller is composed of the establishment of the ATAAN impedance model in the outer‐loop and an adaptive interaction torque‐based controller in the inner‐loop. In the outer‐loop, the patient's muscle torque is estimated by a nonlinear disturbance observer, and the estimated result is used to approximate the patient's active torque. The parameters of ATAAN impedance model are modulated according to the approximation of active torque and the patient's position error to achieve the assist‐as‐needed property. In the inner‐loop, the desired interaction torque, which is required to realize the target ATAAN impedance model, is designed by a robust computed torque controller. The desired trajectory of the exoskeleton is planned online according to the desired interaction torque with the dynamics model of coupling effects. The prescribed performance controller is utilized to achieve accurate trajectory tracking of the exoskeleton, which further enables the interaction torque to track the desired value. The stability of the system and realization of the target ATAAN impedance model are rigorously proved by the Lyapunov method. Co‐simulation experiments are conducted to demonstrate the superiority of the proposed method compared with other existing controllers and its robustness against modeling uncertainties. The effectiveness of the proposed method has been verified through experiments in rehabilitation scenarios.