A Method for Preventing Equipment Damage during the Reaching Operation of Forklifts

This study proposes a method to mitigate property damage accidents during pallet approach (reach) operations of forklifts in the logistics, transportation, and manufacturing industries. Accurate monitoring and control of the reach cylinder is crucial for accident prevention; however, industrial sites often require add-on solutions due to restrictions on modifying existing equipment. Therefore, this study developed a novel approach using non-contact Time of Flight (ToF) sensors. While ToF sensors enable high-precision distance measurement through light round-trip time, they present an inherent challenge for velocity estimation: measurement noise is significantly amplified by numerical differentiation, substantially degrading estimation accuracy. To address this, this study derived a novel velocity estimation algorithm. The proposed approach then applies the resulting velocity data to a reaction force estimation observer, establishing a method for high-precision, real-time estimation of reach cylinder loads. Experimental validation on actual equipment demonstrated the effectiveness of our method and confirmed its applicability as a practical solution for preventing forklift accidents.