Inspired by the dynamics of the noninertial systems, a novel bistable energy harvesting backpack is proposed that improves biomechanical energy harvesting performance. In contrast to traditional bistable energy harvesters that use an oblique compressed spring, a new bistable backpack is developed that uses the change of a spring torque direction located on a pinion. A detailed nondimensionalized model of the novel bistable energy harvesting backpack is developed and analyzed. Based on the dynamic bistable model, the influence of the carried backpack mass on the symmetry and the bifurcation frequency and amplitude of oscillation is examined to determine the ideal design parameters of the bistable backpack for experimental analysis and prototype manufacture. A comparison is made between the new bistable backpack and a traditional linear backpack under both harmonic and human walking excitation. The new bistable backpack design exhibits an improved frequency bandwidth from 1 Hz to 1.65 Hz at the base harmonic excitation of 2 m/s2 and the harvesting performance is enhanced from 2.34 W to 3.32 W when the walking speed is 5.6 km/h. The bench and treadmill tests verify the theoretical analysis and demonstrate the ability of the bistable energy harvesting backpack for broadband and performance enhancement.

Original languageEnglish
Article number115441
JournalEnergy Conversion and Management
Early online date8 Mar 2022
Publication statusPublished - 1 May 2022

Bibliographical note

Funding Information:
Funding: This work is supported by the National Key Research and Development Program of China [grant number 2021YFE0203400], National Natural Science Foundation of China [grant number 51975453 and 51811530321]. and the Royal Society [Grant No. IEC\NSFC\170589].


  • Biomechanical energy harvesting
  • Bistable harvester
  • Energy harvesting backpack
  • Nonlinear design
  • Nonlinear dynamics

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology


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