Design and performance study of a three-degree-of-freedom water injection robotic arm for open-pit coal mines

Aiming at the issues of low degree-of-freedom and outdated structure in existing watering devices for open-pit coal mines, this study designed a novel water-filling robotic manipulator suitable for mining water sprinklers and conducted comprehensive performance investigations. Initially, a new 3-degree-of-freedom (3-DOF) water injection manipulator was developed through a comprehensive consideration of practical working conditions. Subsequently, the kinematic model was established using the Denavit-Hartenberg (D-H) parameters method, with derivation of both forward and inverse kinematic formulas. Furthermore, finite element analysis software was employed to simulate dynamic characteristics, investigating trajectory curves and vibration conditions under varying joint driving speeds. Finally, an experimental platform was constructed to evaluate alignment accuracy through field test data analysis. Results demonstrate that the manipulator exhibits rational structural design and satisfactory alignment accuracy, meeting on-site requirements, thereby establishing a solid foundation for the subsequent development of fully automated intelligent water injection systems.