Investigation of the Light Load in Propelling a Handcart on Various Road Resistances

Abstract

Propelling handcart tasks, such as pushing a wheelchair with an occupant or a handcart with heavy objects are well seen and met in our daily life and occupational works. Office workers and attendants in propelling wheelchairs are physically weaker than workers in industries. Also, aged persons propelling wheelchairs for aged spouses increase in recent aged society in advanced industrialized countries around the world. In this paper, we proposed the linear signal model of worker-cart system based on steady propelling state, and produced the experimental device for investigating the propelling activity in daily life. We analyzed the mechanism of the steady propelling behavior at steady state with the model and device. From experimental results with three subjects in his 20s, we found followings; The proposed model is useful in walking speed 1km/h above. Maximum estimated forces by single leg is around 50N against maximum road resistance, and the force decreases proportionally in walking speed 1km/h above against the decrease of the resistance. Also, autonomous natural pushing force in maximum mechanical power 25-40W, are carried out under exercising heart ratio (EHR) 30%, which shows light load activity to be able to continue over 20min.

Keywords

• handcart
• propelling activity
• worker-cart model
• autonomous propelling
• subjective exercising heart ratio