52 research outputs found

    Three-Stage Design Analysis and Multicriteria Optimization of a Parallel Ankle Rehabilitation Robot Using Genetic Algorithm

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    This paper describes the design analysis and optimization of a novel 3-degrees of freedom (DOF) wearable parallel robot developed for ankle rehabilitation treatments. To address the challenges arising from the use of a parallel mechanism, flexible actuators, and the constraints imposed by the ankle rehabilitation treatment, a complete robot design analysis is performed. Three design stages of the robot, namely, kinematic design, actuation design, and structural design are identified and investigated, and, in the process, six important performance objectives are identified which are vital to achieve design goals. Initially, the optimization is performed by considering only a single objective. Further analysis revealed that some of these objectives are conflicting, and hence these are required to be simultaneously optimized. To investigate a further improvement in the optimal values of design objectives, a preference-based approach and evolutionary-algorithm-based nondominated sorting algorithm (NSGA II) are adapted to the present design optimization problem. Results from NSGA II are compared with the results obtained from the single objective optimization and preference-based optimization approaches. It is found that NSGA II is able to provide better design solutions and is adequate to optimize all of the objective functions concurrently. Finally, a fuzzy-based ranking method has been devised and implemented in order to select the final design solution from the set of nondominated solutions obtained through NSGA II. The proposed design analysis of parallel robots together with the multiobjective optimization and subsequent fuzzy-based ranking can be generalized with modest efforts for the development of all of the classes of parallel robots

    Intelligent robotic rehabilitation system for treatment of disabilities subsequent to injuries or neurological disorders

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    Injuries or neurological trauma, such as stroke, complete and incomplete spinal cord injuries result in paraplegia and hemiplegia, which is the leading cause of disabilities world over. Survivors have muscle coordination discrepancies resulting in impaired joint motions and inability to perform activities of daily living (ADL). Neurological trauma falls in top 15 risk factors for Kazakhstan people and their health conditions. Urgent steps are required to be initiated as the current rate of such disorders is predicted to increase by three times over the next 30 years. Robot assisted physical therapy has shown some preliminary signs of improvement in subjects and therefore active orthosis have been developed to impart repetitive, prolonged and systematic therapy. Existing robots are normally inspired by the industrial robots and thus provide constrained motion to the articulating joints in an uncomfortable and unsafe manner. There is a need to develop human friendly, safe and intelligent robots in order to carry out physical therapy. We aim at developing an intelligent rehabilitation system (IRS) using wearable robots equipped with state of the art sensors and actuators, optimization routines (to identify musculoskeletal functions at the affected limb) and development of advanced controllers. Physical therapy is expected to be evidence based, objective and human friendly

    Intelligent robotic rehabilitation system for treatment of disabilities subsequent to injuries or neurological disorders

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    Injuries or neurological trauma, such as stroke, complete and incomplete spinal cord injuries result in paraplegia and hemiplegia, which is the leading cause of disabilities world over. Survivors have muscle coordination discrepancies resulting in impaired joint motions and inability to perform activities of daily living (ADL). Neurological trauma falls in top 15 risk factors for Kazakhstan people and their health conditions. Urgent steps are required to be initiated as the current rate of such disorders is predicted to increase by three times over the next 30 years. Robot assisted physical therapy has shown some preliminary signs of improvement in subjects and therefore active orthosis have been developed to impart repetitive, prolonged and systematic therapy. Existing robots are normally inspired by the industrial robots and thus provide constrained motion to the articulating joints in an uncomfortable and unsafe manner. There is a need to develop human friendly, safe and intelligent robots in order to carry out physical therapy. We aim at developing an intelligent rehabilitation system (IRS) using wearable robots equipped with state of the art sensors and actuators, optimization routines (to identify musculoskeletal functions at the affected limb) and development of advanced controllers. Physical therapy is expected to be evidence based, objective and human friendly

    Coupling Disturbance Compensated MIMO Control of Parallel Ankle Rehabilitation Robot Actuated by Pneumatic Muscles

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    To solve the poor compliance and safety problems in current rehabilitation robots, a novel two-degrees-offreedom (2-DOF) soft ankle rehabilitation robot driven by pneumatic muscles (PMs) is presented, taking advantages of the PM’s inherent compliance and the parallel structure’s high stiffness and payload capacity. However, the PM’s nonlinear, time-varying and hysteresis characteristics, and the coupling interference from parallel structure, as well as the unpredicted disturbance caused by arbitrary human behavior all raise difficulties in achieving high-precision control of the robot. In this paper, a multi-input-multi-output disturbance compensated sliding mode controller (MIMO-DCSMC) is proposed to tackle these problems. The proposed control method can tackle the un-modeled uncertainties and the coupling interference existed in multiple PMs’ synchronous movement, even with the subject’s participation. Experiment results on a healthy subject confirmed that the PMs-actuated ankle rehabilitation robot controlled by the proposed MIMO-DCSMC is able to assist patients to perform high-accuracy rehabilitation tasks by tracking the desired trajectory in a compliant manner

    Reviewing Clinical Effectiveness of Active Training Strategies of Platform-Based Ankle Rehabilitation Robots

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    Objective; This review aims to provide a systematical investigation of clinical effectiveness of active training strategies applied in platform-based ankle robots. Method. English-language studies published from Jan 1980 to Aug 2017 were searched from four databases using key words of “Ankle” AND “Robot” AND “Effect OR Improv OR Increas.” Following an initial screening, three rounds of discrimination were successively conducted based on the title, the abstract, and the full paper. Result. A total of 21 studies were selected with 311 patients involved; of them, 13 studies applied a single group while another eight studies used different groups for comparison to verify the therapeutic effect. Virtual-reality (VR) game training was applied in 19 studies, while two studies used proprioceptive neuromuscular facilitation (PNF) training. Conclusion. Active training techniques delivered by platform ankle rehabilitation robots have been demonstrated with great potential for clinical applications. Training strategies are mostly combined with one another by considering rehabilitation schemes and motion ability of ankle joints. VR game environment has been commonly used with active ankle training. Bioelectrical signals integrated with VR game training can implement intelligent identification of movement intention and assessment. These further provide the foundation for advanced interactive training strategies that can lead to enhanced training safety and confidence for patients and better treatment efficacy

    Combined Structural and Dimensional Synthesis of a Parallel Robot for Cryogenic Handling Tasks

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    The combined structural and dimensional synthesis is a tool for finding the robot structure that is suited best for a given task by means of global optimization. The handling task in cryogenic environments gives strong constraints on the robot synthesis, which are translated by an engineering design step into the combined synthesis algorithm. This allows to reduce the effort of the combined synthesis, which provides concepts for alternative robot designs and indications on how to modify the existing design prototype, a linear Delta robot with flexure hinges. Promising design candidates are the 3PRRU and 3PRUR, which outperform the linear Delta (3PUU) regarding necessary actuator force

    Evolutionary optimization using equitable fuzzy sorting genetic algorithm (EFSGA)

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    https://ieeexplore.ieee.org/document/8598717This paper presents a fuzzy dominance-based analytical sorting method as an advancement to the existing multi-objective evolutionary algorithms (MOEA). Evolutionary algorithms (EAs), on account of their sorting schemes, may not establish clear discrimination amongst solutions while solving many-objective optimization problems. Moreover, these algorithms are also criticized for issues such as uncertain termination criterion and difficulty in selecting a final solution from the set of Pareto optimal solutions for practical purposes. An alternate approach, referred here as equitable fuzzy sorting genetic algorithm (EFSGA), is proposed in this paper to address these vital issues. Objective functions are defined as fuzzy objectives and competing solutions are provided an overall activation score (OAS) based on their respective fuzzy objective values. Subsequently, OAS is used to assign an explicit fuzzy dominance ranking to these solutions for improved sorting process. Benchmark optimization problems, used as case studies, are optimized using proposed algorithm with three other prevailing methods. Performance indices are obtained to evaluate various aspects of the proposed algorithm and present a comparison with existing methods. It is shown that the EFSGA exhibits strong discrimination ability and provides unambiguous termination criterion. The proposed approach can also help user in selecting final solution from the set of Pareto optimal solutions

    Human Gait Model Development for Objective Analysis of Pre/Post Gait Characteristics Following Lumbar Spine Surgery

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    Although multiple advanced tools and methods are available for gait analysis, the gait and its related disorders are usually assessed by visual inspection in the clinical environment. This thesis aims to introduce a gait analysis system that provides an objective method for gait evaluation in clinics and overcomes the limitations of the current gait analysis systems. Early identification of foot drop, a common gait disorder, would become possible using the proposed methodology
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