Employing variable impedance (stiffness/damping) hybrid actuators on lower limb exoskeleton robots for stable and safe walking trajectory tracking

Kizilhan, Hasbi; Kılıç, Esma

doi:10.1007/s12206-020-0534-4

Cited by 25 publications

(18 citation statements)

References 28 publications

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“…Safety and back-drivability requirements for exoskeleton actuation systems have favored the research and development of new electric actuation solutions, e.g., Series Elastic Actuators (SEA), Variable Stiffness Actuators (VSA), Parallel Elastic Actuators (PEA) and Magneto-Rheological Series Elastic Actuators (MRSEA). Series Elastic Actuators (SEAs) [ 49 , 52 , 63 , 69 , 70 , 71 , 72 , 73 , 74 ] are formed by a spring, or a spring-like component, in series with an electric actuator (usually a BLDC or a DC motor).…”

Section: Analytical Reviewmentioning

confidence: 99%

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Sensors and Actuation Technologies in Exoskeletons: A Review

Tiboni

Borboni

Vérité

et al. 2022

Sensors

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Exoskeletons are robots that closely interact with humans and that are increasingly used for different purposes, such as rehabilitation, assistance in the activities of daily living (ADLs), performance augmentation or as haptic devices. In the last few decades, the research activity on these robots has grown exponentially, and sensors and actuation technologies are two fundamental research themes for their development. In this review, an in-depth study of the works related to exoskeletons and specifically to these two main aspects is carried out. A preliminary phase investigates the temporal distribution of scientific publications to capture the interest in studying and developing novel ideas, methods or solutions for exoskeleton design, actuation and sensors. The distribution of the works is also analyzed with respect to the device purpose, body part to which the device is dedicated, operation mode and design methods. Subsequently, actuation and sensing solutions for the exoskeletons described by the studies in literature are analyzed in detail, highlighting the main trends in their development and spread. The results are presented with a schematic approach, and cross analyses among taxonomies are also proposed to emphasize emerging peculiarities.

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Section: Analytical Reviewmentioning

confidence: 99%

“…Some authors have developed exoskeletons in which both SEAs and VSAs are present. Baser et al, in [ 70 ], presented the lower limb exoskeleton named BioComEx with one variable stiffness actuator (VSA) for the ankle and two series elastic actuators (SEA) for knee and hip joints.…”

Section: Analytical Reviewmentioning

confidence: 99%

Sensors and Actuation Technologies in Exoskeletons: A Review

Tiboni

Borboni

Vérité

et al. 2022

Sensors

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“…The assistance provided by a unilateral exoskeleton can be based on the assumption that the movement of both legs is delayed 180°. This paradigm is called echo-control ( Wang et al, 2013 ) and implies that the movement of one leg can be used to estimate the movement of the contralateral leg to apply an assistive strategy or directly replicate the gait pattern of the non-assisted leg ( Nguyen et al, 2013 ; Kawamoto et al, 2014 , 2015 ; Zhang et al, 2016 ; Xie and Huang, 2019 ; Baser et al, 2020 ; Lora-Millan et al, 2020 ). The prototype developed by Peng et al also based its movement on sound limb kinematics, but according to a leader-follower multi-agent system framework ( Peng et al, 2020 ).…”

Section: State Of the Artmentioning

confidence: 99%

Coordination Between Partial Robotic Exoskeletons and Human Gait: A Comprehensive Review on Control Strategies

Lora-Millán

Moreno

Rocón

2022

Front. Bioeng. Biotechnol.

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Lower-limb robotic exoskeletons have become powerful tools to assist or rehabilitate the gait of subjects with impaired walking, even when they are designed to act only partially over the locomotor system, as in the case of unilateral or single-joint exoskeletons. These partial exoskeletons require a proper method to synchronize their assistive actions and ensure correct inter-joint coordination with the user’s gait. This review analyzes the state of the art of control strategies to coordinate the assistance provided by these partial devices with the actual gait of the wearers. We have analyzed and classified the different approaches independently of the hardware implementation, describing their basis and principles. We have also reviewed the experimental validations of these devices for impaired and unimpaired walking subjects to provide the reader with a clear view of their technology readiness level. Eventually, the current state of the art and necessary future steps in the field are summarized and discussed.

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“…e exoskeleton has become one of the important research subjects in recent years, especially in gait training [1], rehabilitation [2,3], and tremor-suppression orthoses [4]. Almost all existing actuators adopt a driven exoskeleton, including a motor [5][6][7][8][9], hydraulic system [10], pneumatic system [11], and wires [12,13]. Motors possess the advantages of small volume, low weight, large force of traction, simple operation, good performance, and high safety; therefore, they have been widely used in artificial exoskeletons.…”

Section: Introductionmentioning

confidence: 99%

“…e relevant research work mainly focuses on the control algorithm to reduce the error; examples of solutions include adaptive neural network fast fractional sliding mode control [7] and standard force feedback control such as interaction force feedback control and the reference generation [8], adaptive impedance control [9], or sliding mode control [11].…”

Section: Introductionmentioning

confidence: 99%

Man-Machine Synergy Control for Pneumatically Powered Exoskeleton Based on Surface Electromyogram Signal

Jiang

Liu

et al. 2022

Mathematical Problems in Engineering

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The biceps and triceps alternatively act as agonists and antagonists to realize upper limb movement. Pneumatic artificial muscle (PAM), which is inflated and deflated with compressed air instead of water, has similar characteristics to those of human muscle. The challenge is whether an exoskeleton actuated by PAM can help biceps lift the upper limb. Accordingly, the principal aim of this research is to guarantee precise signal collection and control process and adopt the synergy control of PAM and upper limb. In this system, the biceps and triceps provide the main signals in synergy control, electrodes are pasted outside of biceps and triceps to sample their electromyogram signal (EMGs), and the mechanical structure and control system of the pneumatic exoskeleton are proposed. The relationship between duty-ratio-controlled variables and PAM contraction speed is given by experimental analysis, and the maximum duty ratio of controlled variables of input is set to 80. The feature analysis of EMGs can be various including envelope, moving average, and moving root mean square (RMS). The envelope is taken to extract muscle contraction information through upper limb muscles in a static contraction experiment. Then, the processes of biceps and triceps EMGs feature changes including rapid swing, slow swing, and discontinuous swing under various loads are analyzed during upper limb muscle dynamic contraction. The duty-ratio-controlled variables can be divided into five levels, which correspond to exertion rating from powerless to very strong in two EMG characters. These can be reflected in a scatter diagram of duty-ratio-controlled variables and average EMG characters. A nonlinear relationship can be transferred into the continuous system by the polynomial interpolation method, solving the problem of saturation. The net duty-ratio-controlled variables are adopted to control the on-off state and pulse-width modulation (PWM) duty ratio of the high-speed on-off valve. The forearm lifting up movement is unpowered and powered with various load EMGs, and elbow discontinuous swing angle overshoot is performed to analyze the coordination effect in a synergy control experiment.

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Employing variable impedance (stiffness/damping) hybrid actuators on lower limb exoskeleton robots for stable and safe walking trajectory tracking

Cited by 25 publications

References 28 publications

Sensors and Actuation Technologies in Exoskeletons: A Review

Sensors and Actuation Technologies in Exoskeletons: A Review

Coordination Between Partial Robotic Exoskeletons and Human Gait: A Comprehensive Review on Control Strategies

Man-Machine Synergy Control for Pneumatically Powered Exoskeleton Based on Surface Electromyogram Signal

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