Design and control of an MRI compatible series elastic actuator

Şentürk, Yusuf Mert; Patoğlu, Volkan

doi:10.1109/robio.2016.7866535

Cited by 12 publications

(12 citation statements)

References 25 publications

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“…In this paper, we present the design, force control and experimental characterization of MRI-VisAct , a low-cost, Bowden-cable-actuated series viscoelastic actuator for robot-assisted physical rehabilitation during MRI. This work significantly extends our earlier feasibility studies (Senturk and Patoglu, 2016a,b). Even though Bowden-cable-driven series elastic actuation has found use in different force-controlled robot-assisted rehabilitation devices (Erdogan et al, 2017; Veneman et al, 2006), none of these designs target MRI compatibility.…”

Section: Related Worksupporting

confidence: 87%

MRI-VisAct: a Bowden-cable-driven MRI-compatible series viscoelastic actuator

Şentürk

Patoğlu

2017

Transactions of the Institute of Measurement and Control

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Presence of the strong magnetic fields in the Magnetic Resonance Imaging (MRI) environment limits the integration of robotic rehabilitation systems to the MRI process. The tendency to improve imaging quality by the amplification of magnetic field strength further tightens the bidirectional compatibility constraints on MRI compatible rehabilitation devices. We present the design, control, and characterization of MRI-VisAct-a low-cost, Bowden cable-actuated rotary series viscoelastic actuator that fulfills the bidirectional compatibility requirements to the maximum extend. Components of MRI-VisAct that are placed in the magnet room are built using nonconductive, diamagnetic MRI compatible materials, while ferromagnetic/paramagnetic components are placed in the control room, located outside the MRI room. Power and data transmission are achieved through Bowden-cables and fiber optics, respectively. This arrangement ensures that neuroimaging artifacts are minimized, while safety hazards are eliminated, and the device performance is not affected by the magnetic field. MRIVisAct works under closed-loop torque control enabled through series viscoelastic actuation. MRI-VisAct is fully customizable; it can serve as the building block of higher degrees of freedom MRI compatible robotic devices.

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Section: Related Worksupporting

confidence: 87%

MRI-VisAct: a Bowden-cable-driven MRI-compatible series viscoelastic actuator

Şentürk

Patoğlu

2017

Transactions of the Institute of Measurement and Control

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“…Pneumatic actuation has been used in medicine frequently, for example, as dental drills because of their low maintenance and cleanness of air supply. 118 However, challenges exist in the control of pneumatic actuators, such as nonlinearity originating from nonlinear effect of the friction, air compressibility, and parasitic effects of the actuator friction. When the air compressor, filters, accumulators, pneumatic valve, and controllers are located outside the MR environment, the challenges increase, as the need for using long transmission lines to connect both sides is inevitable.…”

Section: Selection Of Proper Actuation and Sensory Systemsmentioning

confidence: 99%

“…However, there are solutions to improve the performance of such systems such as estimating the pressure at each chamber using a model of the system. 118 Pneumatic systems have also been used for other applications such as needle insertion, 119 radioactive seeds implementation in brachytherapy, and study the human motor-control behavior of rehabilitating patients suffering from neurological disorders, such as stroke.…”

Section: Selection Of Proper Actuation and Sensory Systemsmentioning

confidence: 99%

“…Hydraulic is very popular when selecting MR-compatible actuation systems for hand-controllers with high-power output. 118 Nevertheless, the control of hydraulic circuits is extremely challenging, especially in applications that require precise force control such as haptics. Moreover, their performance degrades over time due to high pressure of the fluid and wear and tear of the components in the system.…”

Section: Technical Considerations In Designing Mr-compatible Hhcmentioning

confidence: 99%

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Challenges in developing a magnetic resonance–compatible haptic hand-controller for neurosurgical training

Maddahi

Zareinia

Tomanek

et al. 2018

Proc Inst Mech Eng H

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A haptic device is an actuated human-machine interface utilized by an operator to dynamically interact with a remote environment. This interaction could be virtual (virtual reality) or physical such as using a robotic arm. To date, different mechanisms have been considered to actuate the haptic device to reflect force feedback from the remote environment. In a low-force environment or limited working envelope, the control of some actuation mechanisms such as hydraulic and pneumatic may be problematic. In the development of a haptic device, challenges include limited space, high accuracy or resolution, limitations in kinematic and dynamic solutions, points of singularity, dexterity as well as control system development/design. Furthermore, the haptic interface designed to operate in a magnetic resonance imaging environment adds additional challenges related to electromagnetic interference, static/variable magnetic fields, and the use of magnetic resonance-compatible materials. Such a device would allow functional magnetic resonance imaging to obtain information on the subject's brain activity while performing a task. When used for surgical trainees, functional magnetic resonance imaging could provide an assessment of surgical skills. In this application, the trainee, located supine within the magnet bore while observing the task environment on a graphical user interface, uses a low-force magnetic resonance-compatible haptic device to perform virtual surgical tasks in a limited space. In the quest to develop such a device, this review reports the multiple challenges faced and their potential solutions. The review also investigates efforts toward prototyping such devices and classifies the main components of a magnetic resonance-compatible device including actuation and sensory systems and materials used.

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“…To detach the actuation motor from the end-effector and transmit torque to a distant place, the cable-driven SEA structure has been introduced into physical human-robot interaction (pHRI) systems. Cable-driven SEAs are now widely used for various applications, e.g., for lower limb exoskeletons (Veneman et al, 2006), for arm and wrist rehabilitation robots (Oblak et al, 2010), for elbow joint exoskeletons (Lu et al, 2015), for magnetic resonance imaging (MRI) compatible robots (Senturk and Patoglu, 2016), etc. Impedance control, first described by Hogan in (Hogan, 1985), has been widely adopted in the control of robotic systems to regulate the compliance of interaction or contact tasks.…”

Section: Introductionmentioning

confidence: 99%

Impedance control of a cable-driven SEA with mixed H₂/H_∞ synthesis

Yu¹,

Zou

2017

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Purpose: This paper presents an impedance control method with mixed H 2 /H ∞ synthesis and relaxed passivity for a cable-driven series elastic actuator to be applied for physical human-robot interaction.Design/methodology/approach: To shape the system's impedance to match a desired dynamic model, the impedance control problem was reformulated into an impedance matching structure. The desired competing performance requirements as well as constraints from the physical system can be characterized with weighting functions for respective signals. Considering the frequency properties of human movements, the passivity constraint for stable human-robot interaction, which is required on the entire frequency spectrum and may bring conservative solutions, has been relaxed in such a way that it only restrains the low frequency band. Thus, impedance control became a mixed H 2 /H ∞ synthesis problem, and a dynamic output feedback controller can be obtained.Findings: The proposed impedance control strategy has been tested for various desired impedance with both simulation and experiments on the cable-driven series elastic actuator platform. The actual interaction torque tracked well the desired torque within the desired norm bounds, and the control input was regulated below the motor velocity limit. The closed loop system can guarantee relaxed passivity at low frequency. Both simulation and experimental results have validated the feasibility and efficacy of the proposed method.Originality/value: This impedance control strategy with mixed H 2 /H ∞ synthesis and relaxed passivity provides a novel, effective and less conservative method for physical human-robot interaction control.

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Design and control of an MRI compatible series elastic actuator

Cited by 12 publications

References 25 publications

MRI-VisAct: a Bowden-cable-driven MRI-compatible series viscoelastic actuator

MRI-VisAct: a Bowden-cable-driven MRI-compatible series viscoelastic actuator

Challenges in developing a magnetic resonance–compatible haptic hand-controller for neurosurgical training

Impedance control of a cable-driven SEA with mixed H₂/H_∞ synthesis

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Design and control of an MRI compatible series elastic actuator

Cited by 12 publications

References 25 publications

MRI-VisAct: a Bowden-cable-driven MRI-compatible series viscoelastic actuator

MRI-VisAct: a Bowden-cable-driven MRI-compatible series viscoelastic actuator

Challenges in developing a magnetic resonance–compatible haptic hand-controller for neurosurgical training

Impedance control of a cable-driven SEA with mixed H2/H∞ synthesis

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Product

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Impedance control of a cable-driven SEA with mixed H₂/H_∞ synthesis