Biomechanically integrated cable-driven backpack: Simultaneous energy harvesting and shoulder load alleviation

• A novel cable-driven backpack captures both vertical and horizontal motion energy. • A biomechanical suspension–collision model simulates dynamic shoulder interactions. • A buck-boost DC-DC circuit ensures efficient and stable power management. • The design improves user comfort while powering wearable electronics. Prior work investigated the relative motion between a backpack and the human body during walking, revealing that at lower speeds, horizontal displacement can exceed vertical movement. Based on these findings, we previously developed a lightweight, Cable-driven energy-harvesting backpack capable of collecting dual-directional motion energy without requiring heavy loads or rigid frames. This study focuses on further addressing a critical issue overlooked in existing backpack models—the dynamic impact load caused by intermittent separation and collision between the backpack and the shoulders during walking. A novel biomechanical suspension-collision model was proposed and validated using simulation and experimental, and results demonstrate that the Cable-driven backpack design also effectively reduces peak dynamic loads by approximately 18% at typical walking speeds, enhancing user comfort and gait stability. Furthermore, an integrated power management system was developed using a tailored DC-DC circuit to regulate the harvested energy. The system ensures stable power delivery to low-power electronics while maintaining efficient energy storage and supporting dynamic load modulation. These results confirm the feasibility of using Cable-driven backpack systems not only for energy harvesting but also for improving ergonomic performance in wearable devices.