Modelling Analysis and Realization of a Supporting System for Afflicted Subjects

摘要

Walking assistive devices have wide range of demand through out the year all around the globe. A simple linear mathematical model connecting input output relationship for both angular displacement and knee moment has been derived. Derived mathematical model for knee moment has been compared with the knee moments obtained from newton's equations of motion. The results obtained is validated by comparing with the fabricated structure results. Locomotion have prior importance for any human beings in their life. Hence walking assistive devices are always a boon for the afflicted human beings. At present, variety of walking devices are widely available for different gait irregularities. But the most preferred one is selected depending on the suitable gait characteristics of a subject that it can exhibit. The present walking assistive devices which are more popular and widely available in markets viz., HAL-Hybrid Assistive Limb, exoskeleton, have more focus on the suitability of gait characteristics. Further improvements can be made on walking asstive devices if and only if a perfect gait analysis is carried out and new methods are implemented. A robot suit HAL (hybrid assistive limb) (1) has been developed by T Hayashi et.al, as an walking assistive device for lower limbs. Here the assistive device will develop torque corresponding to myoelectricity signal which has biological information to produce muscle contraction for required torque. BLEEX (2) demonstrated first energetically autonomous, seven degrees of freedom, hydraulically actuated walking assistive device that can carry the payload. A wearable walking helper has been proposed by (3) Takahiko et. al, whose function is to support below hip antigravity muscles. Here the required knee moment for a specific model is calculated based on the antigravity term of necessary knee moment. An assistive device, which can reduce or eliminate the effects of gravity, for persons with hemi paresis to walk was proposed by (4) Sai et. al,. Jerry E Pratt et.al (5) developed a Rob knee which can be worn on the knee and can be used to climb stairs and in acute knee bends during payloads. This has one degree of freedom and requirement of torque that has to be developed at knee is sensed by knee joint angle and ground reaction forces. knee ankle foot orthosis (KAFO) supports the lower limb and enable Partially or fully paralysed people to regain their locomotion.Kenton et.al (6) (7-9) proposed an improved KAFO for an articulated knee joint system that reduces the metabolic energy expenditure during walking. This KAFO improves the knee stability during stance phase by locking the knee and unlocks the knee during swing phase of the gait cycle.