Reaching Difficulty Model of Swinging Operations of a Hydraulic Excavator Considering the First-Order Delay

Hydraulic excavators are used for various purposes, such as excavation, dismantling, and leveling. The accurate positioning of the excavator is particularly important in loading operations, such as positioning a bucket immediately above a target. The positioning of a bucket via the swinging operation can also be regarded as a kind of pointing operation. There are the dynamic characteristics of hydraulic excavators. However, a pointing motion model that considers dynamic characteristics, such as delay, has not been proposed. In this study, the swinging operation of a hydraulic excavator was simulated and experiments were performed to clarify the relation between the dynamic characteristics of hydraulic excavators and their work efficiency. The dynamic characteristics of the swinging operation of the hydraulic excavator were assumed as a first-order system with dead time. Based on this result, a new difficulty model considering dead time and the time constant was proposed, and it was compared with the original Fitts' model based on the coefficient of determination. It was confirmed that the proposed model represented difficulty more accurately compared to the original Fitts' model.