D2.1 Requirements and Specification - CORBYS

D2.1 Requirements and Specification
� adequate ankle dorsiflexion and knee flexion in swing phase for normal foot clearance
4.1.2.2.2 Crouch gait
Figure 3: Crouch gait in sagittal plane
Principal characteristics of crouch walking are:
� plantigrade locomotion (podials and metatarsals flat on the ground)
� pronounced knee flexion / knee extension deficit throughout the gait cycle
� pronounced ankle dorsiflexion throughout the gait cycle
� increased hip flexion
They impose:
� propulsion is achieved predominantly by rapid hip extension instead of forceful extension in all joint
� low C of G due to pronounced knee flexion in stance phase
CORBYS system should restore:
� normal ankle plantar flexion and knee extension prior to contact for proper heel contact and weight
transfer
� normal knee extension to raise the C of G (combined with pelvic vertical translational DOF)
� forceful extension in ankle, knee and hip during push off to assure normal propulsion
4.1.2.2.3 Stiff knee
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