SoftGait: compliant walking assistance via pneumatically actuated robot legs

To assist the mobility handicapped, it is necessary to support their body weight in part using an assistive device. Since the human leg can be modelled by a spring during the gait, the assistive device (or robot) should have a certain level of compliance in order to achieve natural gait assistance. A pneumatic cylinder is added in parallel to a leg (which is also a spring) for antigravity with compliance. By simulation, the compliant gravity assistance effectively reduces the required forces and torques at the joints of leg. Using this idea, a prototype of an assistive robot named SoftGait is developed and experiments are performed to verify its efficacy.