scholarly journals Hybrid Modeling and Fractional Control of a SCKAFO Orthosis for Gait Assistance

2011 ◽  
Author(s):  
S. Hassan HosseinNia ◽  
Francisco Romero ◽  
Blas M. Vinagre ◽  
Francisco Javier Alonso ◽  
Ines Tejado ◽  
...  
Keyword(s):  
Weight Bearing ◽  
Hybrid Modeling ◽  
Knee Motion ◽  
Ankle Foot Orthosis ◽  
Stance Control ◽  
Cord Injury ◽  
Walking Biomechanics ◽  
Control Knee ◽  
Fractional Control ◽  
Foot Orthosis

SCKAFO, stance-control knee-ankle-foot orthosis, is a type of orthosis that permits free knee motion during swing while resisting knee flexion during stance, supporting thereby the limb during weight bearing. This orthosis specially assists patients who have incomplete spinal cord injury and allows them to walk with the aid of canes or crutches, maintaining a proper gait. In this paper, based on the human walking biomechanics, the SCKAFO hybrid modeling is proposed, which consists of eight different stages whose evolution is given by means of four planar sensors on each foot. In the model, it is considered that the patients can move their hip but not their knee that will be controlled using a DC motor. Two fractional order controllers are designed, following decision based control techniques, to control the knee angle. Simulation results are given in order to demonstrate the efficiency of the system performance.

The effect of a knee ankle foot orthosis incorporating an active knee mechanism on gait of a person with poliomyelitis

2013 ◽  
Vol 37 (5) ◽  
pp. 411-414 ◽  
Author(s):  
Mokhtar Arazpour ◽  
Ahmad Chitsazan ◽  
Monireh Ahmadi Bani ◽  
Gholamreza Rouhi ◽  
Farhad Tabatabai Ghomshe ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Walking Speed ◽  
Horizontal Displacement ◽  
Step Length ◽  
Knee Extension ◽  
Knee Joints ◽  
Ankle Foot Orthosis ◽  
Stance Control ◽  
Control Knee ◽  
Foot Orthosis

Background: The aim of this case study was to identify the effect of a powered stance control knee ankle foot orthosis on the kinematics and temporospatial parameters of walking by a person with poliomyelitis when compared to a knee ankle foot orthosis. Case description and methods: A knee ankle foot orthosis was initially manufactured by incorporating drop lock knee joints and custom molded ankle foot orthoses and fitted to a person with poliomyelitis. The orthosis was then adapted by adding electrically activated powered knee joints to provide knee extension torque during stance and also flexion torque in swing phase. Lower limb kinematic and kinetic data plus data for temporospatial parameters were acquired from three test walks using each orthosis. Findings and outcomes: Walking speed, step length, and vertical and horizontal displacement of the pelvis decreased when walking with the powered stance control knee ankle foot orthosis compared to the knee ankle foot orthosis. When using the powered stance control knee ankle foot orthosis, the knee flexion achieved during swing and also the overall pattern of walking more closely matched that of normal human walking. The reduced walking speed may have caused the smaller compensatory motions detected when the powered stance control knee ankle foot orthosis was used. Conclusion: The new powered SCKAFO facilitated controlled knee flexion and extension during ambulation for a volunteer poliomyelitis person. Clinical relevance The powered stance control knee ankle foot orthosis has the potential to improve knee joint kinematics in persons with poliomyelitis when ambulating.

Development of a Dynamic Knee Actuator for a KAFO Using Superelastic Alloys

2014 ◽  
Author(s):  
Feng Tian ◽  
Mohamed Samir Hefzy ◽  
Mohammad Elahinia
Keyword(s):  
Knee Joint ◽  
Gait Cycle ◽  
Swing Phase ◽  
Walking Ability ◽  
Knee Motion ◽  
Walking Gait ◽  
Ankle Foot Orthosis ◽  
Stance Control ◽  
In Series ◽  
Foot Orthosis

A knee-ankle-foot orthosis (KAFO), which covers the knee, ankle and foot, can mitigate abnormal walking pattern caused by weak quadriceps. Several types of KAFOs are currently available in the market: passive KAFOs, stance-control KAFOs and dynamic KAFOs. In passive KAFOs, the knee joint keeps being locked during standing and walking, and can be unlocked manually to allow free rotation for sitting. Stance-control KAFOs (SCKAFOs) allow free knee motion during swing phase when the braced leg is unloaded. Dynamic KAFOs are able to reproduce normal walking ability throughout whole gait cycle. This research is directed at using superelastic alloys to develop a dynamic knee actuator that can be mounted on a traditional passive KAFO. The actuator stiffness can match that of a normal knee joint during the walking gait cycle. This proposed knee actuator utilizes a storing-releasing energy method to apply functional compensation to the knee joint, controlling the knee joint during both stance and swing phases. Fundamentally, the knee actuator is composed of two distinct parts which are connected with the thigh and shank segments, respectively. There are two superelastic actuators that are housed within these two parts and activated independently. Each actuator is developed by combining a superelastic rod and a rotary spring in series. When neither actuator is engaged, the knee joint is allowed to rotate freely. The stance actuator works only in the stance phase and the swing actuator is active for the swing phase. The conceptual design of the knee actuator is verified using numerical simulation and a prototype is developed through additive manufacturing for confirming the concept.

Design of a New Knee Orthosis Locking System

2013 ◽  
Author(s):  
Pedro Moreira ◽  
Pedro Ramôa ◽  
Paulo Flores
Keyword(s):  
Human Gait ◽  
Ankle Foot Orthosis ◽  
Actuation System ◽  
Locking Mechanism ◽  
Stance Control ◽  
Physical Prototype ◽  
Control Knee ◽  
Knee Orthosis ◽  
Foot Orthosis ◽  
Femoris Muscle

The main goal of this work is to present the design of a new locking system for a Stance Control Knee Ankle Foot Orthosis (SCKAFO). The purpose of this solution is to support patients with gait disorders, namely patients with muscular weakness and dystrophy in quadriceps femoris muscle group. The proposed system is able to perform two distinct functions. The first one deals with the locking situation of the orthosis during the stance phase of human gait, in which contact between the foot and the ground occurs. The second function is associated with unlocking situation of the orthosis during the swing phase, in order to allow for the flexion motion of the knee. Thus, in the context of the present work sensors, are used to detect the key phases that characterize the human gait, allowing for the correct system performance. These sensors are placed into anatomical relevant locations and allow the evaluation of the joint angles and accelerations during human gait. Subsequently, the information collected by these sensors is interpreted by a microcontroller that controls the actuation system in order to lock or unlock the knee orthosis locking mechanism. Finally, a physical prototype was built and tested in a traditional knee orthosis, which will allow for its validation. From the preliminary results, it can be stated that the model proposed here differs from the available commercial solutions in the measure that it is dynamic and does not require foot sensors to determine the human gait phases to define the lock/unlock.

Preliminary kinematic evaluation of a new stance-control knee–ankle–foot orthosis

2006 ◽  
Vol 21 (10) ◽  
pp. 1081-1089 ◽  
Author(s):  
Terris Yakimovich ◽  
Edward D. Lemaire ◽  
Jonathan Kofman
Keyword(s):  
Ankle Foot Orthosis ◽  
Stance Control ◽  
Control Knee ◽  
Kinematic Evaluation ◽  
Foot Orthosis
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