Optimizing load carry by using an oscillation system

The purpose of this research is to determine the requirements for a backpack suspension system, which would greatly facilitate the carrying of a backpack by a person. Based on the studies of other authors, it was revealed that the problem of minimizing the energy spent on carrying the load can be solved by reducing the amplitude of the backpack oscillations when a person walks. Therefore, the ideal characteristic of the load suspension system is such a dependence of the resulting force acting on the backpack during its movement, in which the backpack "hangs" at the same level above the ground. The paper considers a backpack with a built-in microgenerator of electrical energy, which works due to the relative movement of the load along the back of a person. In this case, the dependence of the resulting elastic force on the vertical displacement of the human center of mass (CoM) will have the shape of an ellipse. Close to this ideal characteristic can be reproduced using an oscillatory system consisting of four springs, each of which acts on the backpack container for a given period of time. A four-spring suspension allows reducing the amplitude of the backpack oscillations above the ground to 0.02 mm, that is, to reduce the energy costs for carrying cargo to almost zero. The practical implementation of such a system remains a very difficult task. The springs used must have a pronounced non-linear characteristic. That is, they must have a rigid characteristic in order to hold a very massive load in weight, but at the same time be soft so that the load can oscillate in its relative movement along the person’s trunk. It is also necessary to develop a mechanism that, at the right time, switch one or another spring. In further studies, the task was set to determine the operating conditions of the suspension system with changes in the speed of movement and gait of the user.