Development of Robotic Ankle–Foot Orthosis With Series Elastic Actuator and Magneto-Rheological Brake

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Bing Chen ◽  
Bin Zi ◽  
Zhengyu Wang ◽  
Yuan Li ◽  
Jun Qian
Keyword(s):  
Average Power ◽  
Electronic System ◽  
The Body ◽  
Planetary Gearbox ◽  
Ankle Foot Orthosis ◽  
Series Elastic Actuator ◽  
Braking Torque ◽  
Magneto Rheological ◽  
Foot Orthosis ◽  
Series Elastic

Abstract This paper illustrates the development and experimental validation of a robotic ankle–foot orthosis (AFO) with a series elastic actuator (SEA) and a magneto-rheological (MR) brake. First, the biomechanics of a human ankle joint during walking is explained. Next, the hardware design of the robotic AFO is introduced, including its mechanical structure, actuator design and configuration, and electronic system. The SEA is primarily composed of an electric motor, a planetary gearbox, a torsion spring, and a pair of bevel gears. The MR brake can modulate the viscosity of the robotic AFO and generate a large braking torque of 21.8 Nm with a low power of 8.8 W. Additionally, the modeling of the robotic AFO is presented, followed by an introduction to its control; several gait evaluation indices are proposed as well. Finally, a pilot study is conducted to verify the effectiveness of the developed robotic AFO. The experimental results demonstrate that the robotic AFO has the potential to provide dorsiflexion assistance, thus preventing foot slap and toe drag, in addition to plantarflexion assistance for the forward propulsion of the body. During a gait cycle, an average power of 0.23 W is harvested, and an 8% improvement in the system energy efficiency is achieved.

scholarly journals Design and Physical Modelling Series Elastic Actuator for Ankle-Foot Orthosis

2020 ◽  
Vol 9 (5) ◽  
pp. 210-215
Keyword(s):  
Plantar Flexion ◽  
Physical Modelling ◽  
Walking Ability ◽  
Rehabilitation Process ◽  
Ankle Foot Orthosis ◽  
Series Elastic Actuator ◽  
Ankle Movement ◽  
Basic Movement ◽  
Foot Orthosis ◽  
Series Elastic

This paper describes the development of Physical Modelling of Series Elastic Actuator for Active Ankle-Foot Orthosis by using Simscape Multibody Link. Active Ankle-Foot Orthosis is essential that can be used for the rehabilitation process to the patient. It is useful in medicine to help a patient who loses their walking ability, due to ankle weakness, to regain the walking ability. This project focuses on the design, simulate and physical modelling for Ankle-Foot Orthosis. This project was used Solidworks as a platform to design the Active Ankle-Foot Orthosis and using MatLab/Simulink for simulation by using Simscape Multibody Link tools. The Active Ankle-Foot Orthosis moves in 2 basic movement of ankle that is dorsiflexion and plantar flexion for rehabilitation. So, this project focuses on the physical modelling for the Series Elastic Actuator that drives the ankle movement mimicking the normal gait cycle.

scholarly journals The Application of Series Elastic Actuators in the Hydraulic Ankle-Foot Orthosis

2018 ◽  
Author(s):  
Jeong Yong Kim ◽  
William Durfee
Keyword(s):  
Average Power ◽  
Gait Pattern ◽  
High Peak ◽  
High Peak Power ◽  
Ankle Foot Orthosis ◽  
System A ◽  
Power Profile ◽  
Series Elastic Actuators ◽  
Foot Orthosis ◽  
Series Elastic

Advances in ankle-foot orthosis (AFO) technology have been trending toward more powerful and lightweight devices. A hydraulic series elastic actuator (HSEA) was explored to design a lightweight powered AFO that meets the high peak power demand of ankle gait. With its excellent power density and its ability to separate the power supply from the actuator using a hose, hydraulic power was used, combined with an SEA that takes advantage of the high-peak and low-average power profile of ankle gait to store energy and release it during the push-off stage of gait. The parameters required for the SEA were determined and validated using simulation. A gait pattern that would require 235W of motor power was able to be tracked using a motor rated at 95W. The actuator weight of the hydraulic ankle-foot orthosis (HAFO) at the ankle was 0.35, which is 43% of an equivalent electromechanical system. A novel design of an HSEA with a clutch capability is proposed for future HAFO applications.

scholarly journals Development of an Active Ankle Foot Orthosis to Prevent Foot Drop and Toe Drag in Hemiplegic Patients: A Preliminary Study

2011 ◽  
Vol 8 (3-4) ◽  
pp. 377-384 ◽  
Author(s):  
Jungyoon Kim ◽  
Sungjae Hwang ◽  
Ryanghee Sohn ◽  
Younghee Lee ◽  
Youngho Kim
Keyword(s):  
Ankle Joint ◽  
Three Dimensional ◽  
Swing Phase ◽  
Foot Drop ◽  
Initial Contact ◽  
Ankle Foot Orthosis ◽  
Series Elastic Actuator ◽  
Spatial Parameters ◽  
Preliminary Study ◽  
Foot Orthosis

We developed an active ankle-foot orthosis (AAFO) that controls dorsiflexion/plantarflexion of the ankle joint to prevent foot drop and toe drag during hemiplegic walking. To prevent foot slap after initial contact, the ankle joint must remain active to minimize forefoot collision against the ground. During late stance, the ankle joint must also remain active to provide toe clearance and to aid with push-off. We implemented a series elastic actuator in our AAFO to induce ankle dorsiflexion/plantarflexion. The activator was controlled by signals from force sensing register (FSR) sensors that detected gait events. Three dimensional gait analyses were performed for three hemiplegic patients under three different gait conditions: gait without AFO (NAFO), gait with a conventional hinged AFO that did not control the ankle joint (HAFO), and gait with the newly-developed AFO (AAFO). Our results demonstrate that our newly-developed AAFO not only prevents foot drop by inducing plantarflexion during loading response, but also prevents toe drag by facilitating plantarflexion during pre-swing and dorsiflexion during swing phase, leading to improvement in most temporal-spatial parameters. However, only three hemiplegic patients were included in this gait analysis. Studies including more subjects will be required to evaluate the functionality of our newly developed AAFO.

scholarly journals Change in the Mechanical Energy of the Body Center of Mass in Hemiplegic Gait after Continuous Use of a Plantar Flexion Resistive Ankle-foot Orthosis

2013 ◽  
Vol 25 (11) ◽  
pp. 1437-1443 ◽  
Author(s):  
Hirokazu Haruna ◽  
Shunichi Sugihara ◽  
Keisuke Kon ◽  
Tomoya Miyasaka ◽  
Yasuyuki Hayakawa ◽  
...  
Keyword(s):  
Mechanical Energy ◽  
Plantar Flexion ◽  
Center Of Mass ◽  
The Body ◽  
Ankle Foot Orthosis ◽  
Body Center ◽  
Hemiplegic Gait ◽  
Continuous Use ◽  
Foot Orthosis

Development of an Active Walker and its Effect

2012 ◽  
Vol 24 (2) ◽  
pp. 275-283 ◽  
Author(s):  
Hiroshi Kobayashi ◽  
◽  
Takuya Hashimoto ◽  
So Nakayama ◽  
Kazutaka Irie ◽  
...  
Keyword(s):  
Muscular Strength ◽  
Gait Training ◽  
The Body ◽  
Artificial Muscles ◽  
Risk Of Falling ◽  
Ankle Foot Orthosis ◽  
Human Child ◽  
The Many ◽  
The Right ◽  
Foot Orthosis

In Japan alone, more than one million people have walking difficulties. The many kinds of walker being developed thus far for gait training are used by grasping the front and/or back in order to balance the body. This requires tilting the upper half of the body forward or backward, making it difficult to keep the right posture for walking. There are moreover few examples of an active walker that is used if people have no muscular strength for walking. In order to deal with these issues, we have been developing an active walker using the HartWalker which consists of a double upright knee-ankle-foot orthosis and a 4-wheeled carriage with a stem located in the center of the carriage. Since the waist of the orthosis is attached to the top of the stem, there is no risk of falling, it is possible to keep the right posture, and both hands become completely free. McKibben artificial muscles are attached to the Hart Walker in order to control the gait as an active walker. In walking experiments using a child-size doll with the same kinds of joints and weight that a human child has, we confirmed that a humanlike gait is realized by the active walker we developed. Many patients who have different kinds of disease are using it and we have confirmed that all of them can walk by using the active walker. The active walker is now commercially available.

scholarly journals Analysis of body-device interface forces in the sagittal plane for patients wearing ankle-foot orthoses

1999 ◽  
Vol 23 (1) ◽  
pp. 75-81 ◽  
Author(s):  
B. McHugh
Keyword(s):  
Stance Phase ◽  
Muscle Power ◽  
Sagittal Plane ◽  
Swing Phase ◽  
The Body ◽  
Loss Of Function ◽  
Ankle Foot Orthosis ◽  
Ankle Foot Orthoses ◽  
Foot Orthosis ◽  
Interface Forces

An ankle-foot orthosis (AFO) is employed principally to treat musculoskeletal disorders of the ankle and/or subtalar joints although, occasionally, it may be prescribed to provide stance phase control of the knee. In order to function satisfactorily, an AFO must apply appropriate forces to the lower leg in a manner which does not cause local tissue damage or discomfort. Equally the leg will apply forces to the AFO which it must be capable of withstanding without breakage or loss of function. Thus it is useful to know where the body-device interface forces act during walking and to be able to estimate their magnitudes. This is not well understood and has not been satisfactorily documented. This paper explains the force actions between the AFO and the leg, in the sagittal plane, where there is absence of muscle power. Furthermore, it explores the possibility of estimating the magnitudes of these forces. It is found that the forces are greatest when orthotic assistance is needed to compensate for plantar flexor insufficiency in late stance phase. On the other hand, where the AFO is used to support the foot, in the absence of dorsiflexion power in swing phase, the forces are relatively small. Understanding these force levels is relevant to the design of the AFO in terms of choice and use of materials and components.

Design and characterization of a magneto-rheological series elastic actuator for a lower extremity exoskeleton

2017 ◽  
Vol 26 (10) ◽  
pp. 105008 ◽  
Author(s):  
Bing Chen ◽  
Xuan Zhao ◽  
Hao Ma ◽  
Ling Qin ◽  
Wei-Hsin Liao
Keyword(s):  
Lower Extremity ◽  
Series Elastic Actuator ◽  
Magneto Rheological ◽  
Series Elastic

scholarly journals A New Ankle Foot Orthosis for Running

2009 ◽  
Vol 33 (3) ◽  
pp. 192-197 ◽  
Author(s):  
David Bishop ◽  
Allan Moore ◽  
Naveen Chandrashekar
Keyword(s):  
Range Of Motion ◽  
Peroneal Nerve ◽  
Knee Injuries ◽  
Swing Phase ◽  
The Body ◽  
Foot Drop ◽  
Ankle Foot Orthosis ◽  
Ankle Inversion ◽  
Ankle Eversion ◽  
Foot Orthosis

Traumatic knee injuries in automobile accidents and sports often lead to damage of the peroneal nerve. A lack of control of muscles innervated by the peroneal nerve due to this damage, results in the inability to dorsiflex and evert the foot and to extend the toes. This condition is commonly known as foot drop. Foot drop reduces the stability in the body while walking and running and may also cause injury due to lack of foot clearance during the swing phase of the gait. Traditionally, an ankle foot orthosis (AFO), comprised of a moulded sheet of plastic that conforms around the posterior calf and distally contains all or part of the calcaneous as well as the plantar foot, is used to treat foot drop. The intent of this orthosis is to dorsiflex the foot to provide clearance during the swing phase of walking and running. Traditional AFO results in increased pressures due to a decrease in dorsiflexion range of motion at the ankle and make the orthosis increasingly uncomfortable to wear. Several other existing designs of foot drop AFO suffer from similar inadequacies. To address these issues, a new AFO was developed. The device was successfully used by one person with foot drop without issues for more than one year. This new design conforms to the lower anterior shin and dorsum of the foot using dorsiassist Tamarack ankle joints to allow for greater plantar and dorsiflexion range of motion. While still limiting ankle inversion it does allow for more ankle eversion. This orthosis can be discretely worn inside shoes due to its smaller size, and can be worn for a longer period of time without discomfort.

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