Real Time Description of Lower Limb Motion for Nonanalytical Neuroprosthetic Control Applications.

MOSER D; CATALFAMO P; GHOUSSAYNI S N; EWINS D J

Bournemouth, UK

Congreso; 9th Annual Conference of the International Functional Electrical Stimulation Society and the 2nd Conference of FESnet; 2004

Salisbury Health Care

Finite state models of locomotion are often used to incorporate biomechanical knowledge of gait into lower limb neuroprosthetic control systems. The models are typically derived from the contributions of experts in gait biomechanics and rehabilitation technology. The resulting gait patterns can be used to derive stimulation strategies to help restore motor function. Human gait is probably the most studied of human motions, however considerable problems remain in deriving applicable finite state models of gait. This is partly due to the low number of invariant gait characteristics that can be reliably identified in real time. This paper presents a novel method for the finite state modeling of lower limb motion by coding limb segment interactions (CLSI). Angular velocities of limb segments are used to derive a binary code representative of invariant states of locomotion. The method is illustrated using a normative gait record. The resulting code demonstrates that knee flexion and extension phases of gait can be identified in real time in terms of the rotational interactions of the thigh and shank segments. The hardware elements required to derive the code in real time are presented. The application and potential of CSLI coding strategies for the synthesis of nonanalytical neuroprosthetic control systems is discussed.