Original Contribution to the Theory of Biomimetic Compliant Mechanism Design for Prosthetic Limb Actuation Systems Suited to Sub-Saharan African User Populations

Existing prosthetic limb actuation technologies are predominantly designed and validated for user populations in high-income countries, failing to account for the distinctive biomechanical loading profiles, activity patterns, environmental conditions, and economic constraints that characterize the experience of limb-loss in sub-Saharan Africa, where Nigeria has the highest absolute burden of traumatic amputations on the continent. This dissertation presents original contributions to the theory of compliant mechanism design for prosthetic limb actuation by developing a biomimetic analytical framework that integrates pseudo-rigid-body kinematic modelling, non-linear finite element analysis, and multi-objective topology optimization specifically calibrated to the biomechanical requirements and environmental exposure conditions of Nigerian amputee user populations. A comprehensive gait biomechanics database is developed from motion capture and force platform data collected from 84 Nigerian amputees across six geopolitical zones, providing the first Nigeria-specific normative biomechanical dataset for prosthetic design. Novel compliant mechanism topologies for trans-tibial prosthetic ankle joints are synthesized using the proposed framework, and their energy storage and return efficiency, impulse delivery profiles, and fatigue life under Nigerian activity loading spectra are analytically predicted and experimentally validated. The designs achieve 31 percent higher energy return efficiency and 2.4 times longer fatigue life than commercially available carbon fibre prosthetic feet when assessed against the Nigerian activity loading spectrum. A manufacturing pathway using locally sourced composite materials is developed, achieving target costs compatible with Nigerian public prosthetic provision programme budgets. Keywords: compliant mechanism, prosthetic limb, biomimetics, amputee biomechanics, sub-Saharan Africa