Compact MR fluid clutch device for human-friendly actuator

In this study, we propose a leg-shaped robot (Leg-Robot) with a compact magnetorheological fluid clutch to demonstrate several kinds of haptic control of abnormal movements of brain-injured patients. This system can be used in the practical training for trainees of physical therapies (physiotherapists). In this paper, we especially focus on ankle clonus, which is one of the abnormal movements usually arising after stroke. We suggest a control method to demonstrate haptics of the ankle clonus. We also confirmed its effectiveness for learning of the test skill.

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“…3). This device has a quick response (time constant: 20 ms) and good torque (above 5 Nm)/weight (237 g) ratio [12]. As shown in Fig.…”

Section: Compact Mrf Clutch (Cmrfc)mentioning

confidence: 95%

“…We also confirmed its effectiveness for learning the test skill by using this system. clutch [11,12] between a user (e.g., therapist) and an actuator. This clutch-driven mechanism has several merits when compared with the direct-drive mechanism:…”

Section: Introductionmentioning

confidence: 99%

Leg-Robot for Demonstration of Spastic Movements of Brain-Injured Patients with Compact Magnetorheological Fluid Clutch

2010

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“…In our previous study, [12] we developed a compact MR fluid brake, which has a multi-layered disk structure and narrow gaps between fluid layers. MR fluids are a functional fluid whose rheological properties can be changed by applying an external magnetic field.…”

Section: I-walkermentioning

confidence: 99%

“…Originally, we developed a compact MR fluid brake that was built in the wheels of the walker. [12] These special brakes enabled us to realize compact torque-controllable wheels. We installed these in-wheel brakes along with an inexpensive web camera on a widely used caster walker, which we termed the intelligently controllable walker (i-Walker).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of line-tracing controller of intelligently controllable walker

et al. 2013

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Caster walkers are supporting frames with casters and wheels that are regularly used as walking-aids in hospitals, nursing homes, and by individuals. The casters and wheels of the walker provide mobility to elderly users. However, when the walker moves in unexpected directions, falling accidents often occur. These accidents pose a very serious problem and are one of the leading causes of secondary injuries and disorders. Caregivers support patients with impaired motor or sensory functions by standing next to them when they walk. The main interests of this study are the development of an intelligent walker and the realization of a safe walker for the elderly and disabled. In our previous study, we developed the intelligently controllable walker (i-Walker) that utilized compact MR fluid brakes in its wheels and a web camera. In addition, we had proposed a line-tracing controller for i-Walker, whose performance was evaluated by healthy subjects. In this study, three elderly subjects suffering from different disabilities used i-Walker, and we evaluate the effects of the line-tracing control in the elderly gaits. To perform this task, we installed on i-Walker a gait measurement sensor. The gait sensor measures the step lengths and stride widths of subjects, which we use in our evaluation. Each gait was evaluated on the basis of the positional error, reaching time, step length, and stride width. The results show that the line-tracing controller of i-Walker reduced positional errors, but increased reaching times. Moreover, the line-tracing control of i-Walker improved the balance in the step length and reduced the stride width of a subject suffering from imbalance motion caused by a fracture.

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“…Furthermore, the MRFs have also been used to develop "haptic interfaces" capable of simulating objects in virtual environments [12]- [19]. As for magnetorheological clutches, several solutions have been proposed in the past years [20]- [30]. In all these solutions, it is a wired conventional coil that excites the fluid in order R. Rizzo to transmit a suitable torque.…”

Section: Introductionmentioning

confidence: 99%

Magnetic FEM Design and Experimental Validation of an Innovative Fail-Safe Magnetorheological Clutch Excited by Permanent Magnets

Rizzo

Musolino

Bucchi

et al. 2014

IEEE Trans. Energy Convers.

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This paper describes the magnetic design of an innovative fail-safe clutch based on magnetorheological fluid (MRF). A cylindrical arrangement of permanent magnets (PMs) is used to excite the fluid. The suitable distribution of magnetic field inside the MRF and the transmissible torque is obtained by moving the PMs along the axial direction. The device is designed using a magneto/mechanical FEM model, developed on purpose and based on a three-dimensional (3-D) finite-element code, which takes into account the B-H and τ -H functions of the nonlinear materials (e.g., MRF, PM, and ferromagnetic materials). The flux density maps and the shear stress maps inside the fluid are carefully analyzed. Furthermore, in order to validate the FEM model, some preliminary experimental measurements are performed on a prototype. Finally, the magnetic axial force acting on the PM system is investigated.Index Terms-FEM analysis, magnetorheological clutch, permanent magnets.

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Compact MR fluid clutch device for human-friendly actuator

Cited by 36 publications

References 2 publications

Leg-Robot for Demonstration of Spastic Movements of Brain-Injured Patients with Compact Magnetorheological Fluid Clutch

Leg-Robot for Demonstration of Spastic Movements of Brain-Injured Patients with Compact Magnetorheological Fluid Clutch

Evaluation of line-tracing controller of intelligently controllable walker

Magnetic FEM Design and Experimental Validation of an Innovative Fail-Safe Magnetorheological Clutch Excited by Permanent Magnets

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