Alireza Mostafavi - Graduate Student, school of Mechanical Engineering, College of Engineering, University of tehran, iran
Mohamad Reza Zakerzadeh - Associate professor, School of Mechanical Engineering,college of Engineering University of tehran,, Iran.
Ali Sadighi - Associate professor, School of Mechanical Engineering,college of Engineering University of tehran,, Iran.

During the past couple of decades , energy from human body motion has been sx-plored extensively to provide electricity needed for energizing cell phones and other gadgets. In this paper, an optimized design of a suspended-load backpack with a mechanical motion rectifier (MMR) is presented. The system parameters were obtained for producing maximum output power with an 8-kg backpack, which is the lightest proposed in previous studies. Simulations show that 6.92W of electrical energy can be harvested from human walking. Alongside the numerical simulation, some experiments were conducted to verify it. A prototype of the backpack is fabricated, and a maximum average power of 4.37 Watts and instant power of 11.57 Watts were obtained by onesubject while walking with normal walking speed, carrying the MMR-based backpack harvester and 8 kg of the load mass. This power is the most average output power with normal walking speed and the payload of 8 kg among previous studies.

Energy harvesting backpack, mechanical motion rectifier, human motion