Robust Control of a Cable-Driven Soft Exoskeleton Joint for Intrinsic Human-Robot Interaction

Jarrett, Christopher; McDaid, Andrew

doi:10.1109/tnsre.2017.2676765

Cited by 56 publications

(38 citation statements)

References 31 publications

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“…An inner controller based on sliding mode control regulates the relative displacement of the SEA components, thus controlling the torque in an impedance-based architecture (Jarrett and Mc Daid, 2017). …”

Section: Methodsmentioning

confidence: 99%

Virtual Normalization of Physical Impairment: A Pilot Study to Evaluate Motor Learning in Presence of Physical Impairment

Jarrett

McDaid

2017

Front. Neurosci.

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Motor learning is a critical component of the rehabilitation process; however, it can be difficult to separate the fundamental causes of a learning deficit when physical impairment is a confounding factor. In this paper, a new technique is proposed to augment the residual ability of physically impaired patients with a robotic rehabilitation exoskeleton, such that motor learning can be studied independently of physical impairment. The proposed technique augments the velocity of an on-screen cursor relative to the restricted physical motion. Radial Basis Functions (RBFs) are used to both model velocity and derive a function to scale velocity as a function of workspace position. Two variations of the algorithm are presented for comparison. In a cross-over pilot study, healthy participants were recruited and subjected to a simulated impairment to constrain their motion, imposed by the cable-driven wrist exoskeleton. Participants then completed a sinusoidal tracking task, in which the algorithms were statistically shown to augment the cursor velocity in the constrained state such that it matched position-dependent velocities recorded in the healthy state. A kinematic task was then designed as a motor-learning case study where the algorithms were statistically shown to allow participants to achieve the same performance when their motion was constrained as when unconstrained. The results of the pilot study provide motivation for further research into the use of this technique, thus providing a tool with which motor-learning can be studied in neurologically impaired populations. This could be used to give physiotherapists greater insight into underlying causes of motor learning deficits, consequently facilitating and enhancing subject-specific therapy regimes.

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Section: Methodsmentioning

confidence: 99%

Virtual Normalization of Physical Impairment: A Pilot Study to Evaluate Motor Learning in Presence of Physical Impairment

Jarrett

McDaid

2017

Front. Neurosci.

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“…In rehabilitation, robotic devices have been deployed to assist patients after stroke to move their impaired limb through a pre-defined trajectory. This movement uses both a linear and nonlinear approach [41,68,91] used a PD controller which has limitations of having some steady date error in trajectory tracking. On the other hand [58,60,73,74,106,107,126] used a different approach (PID) in which an integral term was added in the controller to compensates for steady state error during the robot-aided therapy.…”

Section: Control Issuesmentioning

confidence: 99%

A Brief Review on Robotic Exoskeletons for Upper Extremity Rehabilitation to Find the Gap between Research Porotype and Commercial Type

et al. 2017

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The number of disabled individuals due to stroke is increasing day by day and is projected to continue increasing at an alarming rate in United States. But the current amount of health professionals in physical therapy is inadequate to provide rehabilitation to these large groups. From early 1990s, researchers have been trying to develop an easy and feasible solution to this problem and lot of assistive devices both end effector type or exoskeleton type have been developed till to date. However, only a few of them have been commercialized and are being used in rehabilitation of post-stroke patients. Making the use of exoskeletons and other devices to regain lost motor function is rare. Providing therapy to this large group is quite impossible without commercializing of exoskeleton. This has motivated the authors to make a literature review and figure the reasons out that need to be solved to bridge the gap between research prototype to commercial version. This paper covers the necessity of incorporating robotic devices in rehabilitation, a brief description of existing devices particularly upper limb exoskeletons, their hardware limitations, and control issues. Our review shows that there are significant flaws in hardware design and developing control algorithm of exoskeletons to be available in rehabilitation program.

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“…4,5 Hence, cable-driven robots are attracting the attention of researchers for its simpler structure, light weight, lower energy consumption and better human–robot interaction security compared with the conventional rigid structure robots. 6–9 Nevertheless, the introduction of cable-driven technology brings about the problem of joint coupling and cable vibration, and the system is sensitive to external interferences due to flexibility of the driving cable. Besides, the dynamic model of a compliance cable-driven system is more complex than that of a rigid one, and accurate model is almost impossible to obtain on account of the existence of external disturbances and parameter uncertainties.…”

Section: Introductionmentioning

confidence: 99%

Practical continuous nonsingular terminal sliding mode control of a cable-driven manipulator developed for aerial robots

Zhao

Wang

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part I:

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With the increasing demand for air operations, in this article, a control algorithm is proposed for a novel light cable-driven manipulator developed for aerial robots. On account of the control problem of cable-driven manipulators, we design a time delay estimation–based nonsingular terminal sliding mode controller with a fuzzy logic system to further improve the precision of joint position tracking. First, time delay estimation technique is adopted to estimate unknown dynamics of the manipulator system. And thanks to time delay estimation, accurate dynamic model is not needed and thus the controller is model-free which makes it more practical. The main part of the controller is nonsingular terminal sliding mode which ensures satisfactory tracking precision and good robustness under time delay estimation error and external disturbances. Besides, the boundary layer is introduced for reducing chattering and was regulated by a fuzzy logic system to realize a faster convergence. Global stability and finite time convergence to equilibrium of the closed-loop control system are analyzed using Lyapunov stability theory. Finally, comparative experiments are conducted through a newly designed planar cable-driven manipulator. Experimental results show that the proposed controller has a better performance compared with a conventional nonsingular terminal sliding mode controller while control effort is almost the same.

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Robust Control of a Cable-Driven Soft Exoskeleton Joint for Intrinsic Human-Robot Interaction

Cited by 56 publications

References 31 publications

Virtual Normalization of Physical Impairment: A Pilot Study to Evaluate Motor Learning in Presence of Physical Impairment

Virtual Normalization of Physical Impairment: A Pilot Study to Evaluate Motor Learning in Presence of Physical Impairment

A Brief Review on Robotic Exoskeletons for Upper Extremity Rehabilitation to Find the Gap between Research Porotype and Commercial Type

Practical continuous nonsingular terminal sliding mode control of a cable-driven manipulator developed for aerial robots

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