Along with the development of technology and mobile electronic devices arose the need for mobile energy resources. One way to fulfil this need is using a technology which exploits the human body movement and the hit it emits to generate electricity.

This thesis is part of a research that begun 8 years ago and focuses on converting kinetic energy from the body joints to electrical energy and offers solution for the electrical energy availability problem. This is a multi-disciplinary research which incorporates the fields of mechanical engineering, electrical engineering and industrial engineering.

The main idea of this technology is to use the wasted energy from the human body, particularly from the knee joint, by converting the mechanical energy of walking to electrical energy. As part of the research we developed a portable device. When walking on a plain, about 90% of the knee muscles work uses for braking, this braking called “negative work” which defines as when the knee torque direction is opposite to the angular velocity direction. The device uses part of this “negative work” from the knee joint.

In a straight plain, the gait cycle divided to 4 segments, 3 segments are negative work. In these segments the device converts some of the braking actions of the muscles. By doing so, it helps the user and lower is metabolic consumption while harvesting electrical energy. The measure to examine the efficiency of the device is COH (Cost Of Harvest). The COH is calculated by the ratio between the changes in metabolic consumption to the harvested electrical power. The goal of this research is to find the specific point where we get the best work from the device, and analyze the physiological changes as a result of using the device.

The device is a mechanical apparatus fixed on an orthopedic knee brace adapted to human lower limb. The device includes gear train system, generator and a controller. In this research algorithms were designed to identify the user’s walking profile in real time, the physiological effects on the user were examined and mechanical parts of the experiments system were improved.

During the research 4 users were tested in two different times, we tested the effects of different harvest levels on the amount of electricity harvested, metabolic consumption (effort level), muscles electrical activity level, changes in angular profile and torques and the power in the joints. While examining the results we found that harvest level of 30% braking of the device for energy harvest is the best level when examining the COH.