1st Generation Bionic Energy Harvester

Walking is surprisingly similar to stop-and-go driving, with muscles accelerating and slowing down the body even within a stride. On average, there is no net mechanical work performed by the body during walking at a constant speed on level ground, as there is no net change in kinetic or potential energy. This is accomplished by a number of elements that include muscle, tendon, clothing, and air resistance all contributing to perform positive and negative mechanical work. Selectively engaging a generator at the right times and in the right location on the body can assist with performing negative mechanical work, replacing work normally provided by other sources such as muscles. This is similar to how regenerative braking generates power while decelerating a hybrid car.

The knee is the best location for energy harvesting, as it is the locus of negative work during walking, unlike the hip or the ankle joints. There are four main phases of knee kinematics on level ground. It can be seen that there is significant negative power at the knee during swing extension, stance flexion and swing flexion. The amount of power available in each region varies with the slope of the terrain. For instance, stance flexion and swing flexion power increases dramatically on a down slope.

Category:

Science & Technology

Tags:

• Bionic
• Energy
• Harvester