Kikuko Otsuki

Development of a Compact Magnetorheological Fluid Clutch for Human-Friendly Actuator

There is a strong demand for a human–machine-coexistent machine, e.g., a power-assist system or a computer-aided rehabilitation system, in the context of the super-aging society. In such a human–machine-coexistent system, it is important to guarantee hardware-level safety by utilizing human-friendly actuators. In this study, we have developed a compact magnetorheological fluid clutch (CMRFC) for human-friendly actuators. In this paper, at first, the basic design of the CMRFC and developments of 5- and 40-Nm class devices are explained. Then we discuss experimental results on the basic characteristics of these devices. In the final part, a new magnetorheological fluid that includes nano-sized particles is discussed.

Development of third-generation intelligently Controllable ankle-foot orthosis with compact MR fluid brake

Ankle-foot orthoses (AFOs) are orthotic devices that support the movement of the ankles of disabled people, for example, those suffering from hemiplegia or peroneal nerve palsy. We have developed an intelligently controllable AFO (i-AFO) in which the ankle torque is controlled by a compact magnetorheological fluid brake. Gait-control tests with the i-AFO were performed for a patient with flaccid paralysis of the ankles, who has difficulty in voluntary movement of the peripheral part of the inferior limb, and physical limitations on his ankles. By using the i-AFO, his gait control was improved by prevention of drop foot in the swing phase and by forward promotion in the stance phase.

Compact MR fluid clutch device for human-friendly actuator

In this paper, we describe a design method and experimental results of a newly developed MR Fluid clutch which has a multi-layered disks and micro-size (50 micro meters) gaps of MR Fluid. The micro-size gap works for the reduction of magnetic resistance, amount of power supply and size of the total system. Static torques of the device was predictable with conventional magnetostatic analyses. Additionally, dynamic test shows that its response time is about 20 milliseconds.

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

Ankle-Foot Orthoses (AFOs) are orthotic devices supporting movements of ankles for disabled people for example hemiplegia, peroneal nerve palsy, etc. In our research, we have developed the intelligently controllable AFO (I-AFO) which can control its ankle torque by using compact Magneto-rheological fluid (MRF) brakes. In this paper, we describe the gait-control tests with I-AFO for a patient of the Guillain-Barre syndrome. The subject has difficulty in his voluntary movement of the peripheral part of the inferior limb, and there are physical limitations on his ankle. By applying the I-AFO, his gait control was improved by the prevention of drop-foot in the swing-phase and the forward promotion in the stance-phase.

Compact MR Fluid Actuator for Human Friendly System

There is a strong demand for a human-machine-coexistent machine, e.g. a power-assist system or a computer-aided rehabilitation system, in the face of the super-aging society. However, the research and development of the actuator that considers safety for such a robot system is hardly achieved. In this study, we research and develop human-friendly compact MR fluid actuator (MRF actuator) with high safety. In this paper, at first, we describe the concept of the human-machine-coexistent system. Secondly, basic design of the MR actuator with multilayered disks and narrow-gaps, and development of 5 Nm and 40 Nm MR actuators are explained. Finally, we discuss development of New MR fluids with nanopaticles.

Development of Intelligent Ankle-Foot Orthosis (i-AFO) with MR Fluid Brake and Control System for Gait Control

Ankle-Foot Orthoses (AFOs) are orthotic devices supporting movements of ankles of disabled people for example hemiplegia, polio, peroneal nerve palsy, etc. In our research, we have developed intelligently and passively controllable AFOs (i-AFO) which can control its ankle torque with a compact Magneto-rheological fluid brake (MRB). In this paper, we describe a design method and a control method of the i-AFO. In the final part of this paper, we present experimental results in which the i-AFO was applied to gait control for a polio patient.

Basic study on prediction of initial contact for intelligently controlled ankle foot orthosis (I-AFO)

Ankle-Foot Orthoses (AFOs) are orthotic devices supporting movements of ankles of disabled persons for example hemiplegia, polio, peroneal nerve palsy, etc. In our previous research, we developed some kinds of passive controllable AFO which can control ankle torque with Compact Magnetorheological fluid brakes. One of the remarkable key points of its control is damping control at initial contacts. We think that a prediction of the initial contact is effective for its control because the initial contact usually ends very instant moment of about 0.1s. In this paper, we describe basic control method of our controllable AFO and prediction method of the initial contact for it. Finally, we could predict instant contacts before 0.1s with the absolute error of 0.020s.