Estimation of the Center of Gravity Position Transition by Image Processing in Manual Material Handling

Based on a survey of previous studies, it is estimated that low back pain will affect 619 million people worldwide in 2020 and increase to 843 million by 2050, mainly due to population expansion and aging. One of the measures to prevent low back pain is to be aware of the center of gravity in the working posture. When the center of gravity is lowered, the posture becomes more stable and it is easier to exert force on the body. When lifting an object, the closer the distance between body's center of gravity and the object's center of gravity in the horizontal plane, the less force is required to lift the object. This also implies that the greater the distance between body's center of gravity and the object's center of gravity, the greater the compressive stress on the lower back and the greater the risk of lower back pain. Therefore, the purpose of this study is to estimate the position of the subject's center of gravity during manual material handling by image processing. By estimating the worker's posture and the transition of body's center of gravity during the lifting operation, we analyze the mechanical characteristics of the lifting operation.