Discrimination of Lifted Object Weight Using a Triaxial Accelerometer When Lifting an Object of Unknown Weight by the Stoop Lifting

In modern-day Japan, a society facing issues related to an aging population and declining birth rates, there exists a shortage of nurses and caregivers. One of the contributing factors to this shortage is attributed to low back pain (LBP). Considering the current environment of hospitals and care facilities, a more straightforward approach should be adopted for the prevention and improvement of LBP. Therefore, this study aims to raise awareness of the risk of LBP through the determination of lifted object weight, and encouraging individuals to actively engage in prevention of LBP. Previous study demonstrated the feasibility of distinguishing between objects weighing Okg and 25kg during lifting motions based on spikes in acceleration data. However, there is a need to differentiate between weights with smaller differences. Hence, this study focuses on lifting objects of unknown weight by the stoop lifting that are known to impose significant lumbar strain, and proposes a method for discerning between objects weighing 10kg and 20kg using a single triaxial accelerometer. This differentiation is achieved by measuring changes in posture during lifting motions through the decomposition of gravitational acceleration. The effectiveness of this study is verified through the discrimination accuracy calculated using Support Vector Machine (SVM) analysis.