Techno Press
Techno Press

Smart Structures and Systems
  Volume 37, Number 5, May 2026 , pages 429-450
DOI: https://doi.org/10.12989/sss.2026.37.5.429
 

Energy dissipation and operating time analysis of a vibro-impact capsule robot powered by lithium battery under PWM control
Ngoc-Hung Chu, Van-Du Nguyen, Quoc-Huy Ngo

 
Abstract
    This paper investigates energy dissipation and operating time of a vibro‑impact capsule robot powered by a compact LIR1040 lithium battery under pulse‑width modulation (PWM) excitation. An improved mathematical model incorporating coil inductance and a nonlinear excitation force is developed and validated against experiments. Numerical simulations and laboratory tests quantify losses from viscous damping, Coulomb friction, and impact events, and show their dependence on excitation frequency and duty cycle. Analysis of hysteresis loops of impact force versus relative displacement and relative velocity clarifies how collision dynamics convert mechanical energy into irreversible loss. Higher frequencies generally favor forward locomotion with reduced impact losses, while lower frequencies produce larger instantaneous displacements and faster energy dissipation. Comparison of theoretical operating time based on battery capacity with operating time accounting for voltage decay reveals that voltage drop substantially shortens effective operation. Practical PWM tuning guidelines are provided to balance locomotion efficiency and battery endurance for biomedical and industrial applications.
 
Key Words
    active capsule; energy dissipation; lithium battery endurance; micro‑robotics locomotion; nonlinear dynamics; PWM excitation; vibro-impact
 
Address
(1) Ngoc-Hung Chu:
Trade Union University, No. 169 Tay Son Street, Kim Lien Ward, Hanoi, Vietnam;
(2) Van-Du Nguyen, Quoc-Huy Ngo:
Department of Mechanical Engineering, Thai Nguyen University of Technology, 3/2 Street, Thai Nguyen City, Viet Nam.
 
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