Development of Shear Type Compact MR Brake for the Intelligent Ankle-Foot Orthosis and Its Control; Research and Development in NEDO for Practical Application of Human Support Robot

Abstract

A brake in which the magnetorheologic fluid (MRF) is used has a simple structure and good responsibility. Therefore, MR brake is expected to perform a good adaptability for human-coexistence system. Being applied in an ankle-foot orthosis, however, conventional MR brake is too large to fit. Then, in this study we developed a shear-type MR brake with multi layer disks and minute gaps (50 micrometers) to realize compactness and high performance. This paper describes the development of a shear type compact MR brake and a new controllable ankle-foot orthosis with this brake. Furthermore, we design algorithm to control an ankle. We assist gait of a patient by changing a brake force.

Flexible Medical Devices: Review of Controllable Stiffness Solutions

“…The elastic behavior of MR and ER fluids is difficult to evaluate, and the literature gives the yielding stress for both fluids [67][68][69][70]72]. MR fluids give higher yield results than ER and can work at lower voltages [66].…”

“…A knee prosthetic for amputees with an MR fluid-based damper is presented in [80]. An MR fluid damper is also used in the development of active ankle prosthetics [72,174]. An active knee brace is presented in [79] and an MR fluid-based knee prosthesis in [78].…”

Intelligently controllable Ankle Foot Orthosis (I-AFO) and its application for a patient of Guillain-Barre syndrome

“…The passive controllable AFO also have a great advantage for cost, safety and downsizing. In our previous research [11], we developed some kinds of intelligently controlled AFO (I-AFO) which can control ankle torque with compact magneto-rheological fluid brakes (MRB) [12]. In this paper, we describe the gait-control tests with the I-AFO for a patient of the Guillain-Barre syndrome.…”

Modeling, control, and analysis of a robotic assist device

“…Powered orthoses address these limitations through the combined use of sensors, actuators, and computer control to provide torque assistance and motion control for lower limb joints [7][8][9][10][11][12][13]. A specific example of a powered AFO is the portable powered ankle-foot orthosis (PPAFO), Fig.…”