Kinematic and dynamic analysis of long-reach excavator equipped with drum cutter for dredging tasks

Abstract

Operating characteristics (e.g., working area, kinematic and dynamic responses) of hydraulic excavators equipped with standard buckets is inherently defined by the dimensions of links, the corresponding characteristics of driving cylinders, and working conditions. For dredging construction, it is often necessary to integrate additional equipment into the original hydraulic excavator. Excavators mounted on pontoons and equipped with drum cutters are commonly employed for this purpose. Investigating the working performance of these devices is essential for integrating replacement equipment into excavators to meet specific design criteria, technical requirements, and operational spaces. The installation of an extended boom and the modification of the working attachment to meet dredging requirements have resulted in fundamental changes in the kinematic and dynamic characteristics of the working mechanism. Specifically, the addition of a long dynamic link and the presence of resistive forces that vary continuously due to the cutter teeth alternately entering and exiting the cutting zone represent key differences compared to the original machine. This study introduces an innovative configuration for a standard excavator by incorporating a long-reach arm and substituting the bucket with a drum cutter. This modification aims to enhance the excavator's effectiveness in dredging tasks. In addition to extending the reachable working area to more than twice that of the original configuration, the translational velocity of the drum cutter can exceed that of the actuating cylinder by over 30 times. From a dynamic response perspective, the cutting layer thickness is shown to have a pronounced influence on the variation of resistive force components, driving forces, and joint reaction forces, with the coefficient of variation (CV) reaching values of up to 38.02 %. When the cutting depth is increased by a factor of 1.5, the CV of the force components decreases by the same ratio; however, the magnitudes of these force components may increase by more than four times. Through a comprehensive kinematic and dynamic analysis, the modified working area and operating characteristics of the backhoe dredger are evaluated to ensure safe, efficient, and structurally optimized operations. The proposed design and the findings of the present research offer valuable insights and practical solutions for the manufacturing and improvement of dredging equipment.