Design of an Assistive Gait Device for Strength Endurance and Rehabilitation

1.1 Background Exoskeletons for human performance augmentation (EHPA) are controlled and wearable devices and machines that can increase the speed, strength, and endurance of the operator. EHPA is expected to do that by increasing the physical performance of the solider wearing it, including: • Increased payload: more fire power, more supplies, and thicker and heavier armor increasing the soldier chance of surviving a direct hit or even an explosion. • Increased speed and extended range: enhanced ground reconnaissance and battle space dominance. • Increased strength: larger caliber weapons, obstacle clearance, repairing heavy ma chinery such as tack. Besides these, "Imagine the psychological impact upon a foe when encountering squads of seemingly invincible warriors protected by armor and endowed with superhuman capabilities, such as the ability to leap over 20-foot walls, " said Ned Thomas, the director of Institute for Soldier Nanotechnologies (ISN) (Wakefield, 2002). Another use of exoskeletons is that they could help integrate women into combat situations. John Knowles, publisher of the defense industry newsletter, The Knowles Report, said that in terms of marksmanship and other combat skills, "Women have proven themselves very equal." The prevailing argument against women in combat is that most can't meet the job's physical requirements. Exoskeletons, could "radically equalize that," thus enabling a 130-pound woman to lift, carry and be as effective as a 180-pound man (Hembree, 2001). In non-military areas, one of the most possible applications of exoskeletons may be used to help aged or disabled people whose lower extremities have locomotor deficiencies due to various reasons: polio, paraparesis, paralysis, dystrophia, etc. They are unable to walk without assistance and may lose muscular strength in their legs and become bedridden. They can only move around by a wheelchair or by using a wheeled walker. Unfortunately, barriers such as bumps and steps restrict the area that these people have access to. It is hoped that the lower exoskeleton can enhance their muscular strength and enable them walk as normal people.