Dynamic Simulation Of Working Device Of Three-arm Backhoe Hydraulic Excavator

Backhoe hydraulic excavator is a major type of construction machinery,which plays a very important role in earthwork construction and building engineering.The working device is one of the main components of this type of excavator,and the integral boom is the main structural form of excavator.Its structure is simple,easy to manufacture,and its use and maintenance cost is low,but its adaptability is poor when the use occasion changes,such as narrow deep ditch,wide river channel and so on.The combined boom has good adaptability to special excavation occasions,and the included angle between the two booms can be changed by adjusting the length of the hydraulic cylinder of the upper boom,so that the excavator can meet the requirements of different working conditions.Domestic research on three-arm hydraulic excavators started late,and there are few types of hydraulic excavators,so it is of great significance to analyze its research background and application at home and abroad.In this paper,the kinematics,theoretical digging force and dynamics of the working device of the three-arm wheeled hydraulic excavator are analyzed and studied.Firstly,using D-H linkage coordinate transformation,the kinematics equation of three-arm hydraulic excavator is established,and the position and attitude of bucket tip relative to the base coordinate system are obtained.The velocity and acceleration of working device are solved by Jacobian matrix.Secondly,the model of three-arm wheeled hydraulic excavator is created in Pro/E,and ADAMS software is imported to simulate and draw the excavation envelope diagram.The relationship between the length of the upper boom hydraulic cylinder and the main working dimensions of the excavator is analyzed,which provides a theoretical basis for the design and performance analysis of the three-arm wheeled hydraulic excavator.Thirdly,using vector mechanics method,the calculation formula of theoretical excavation force of the whole machine under any attitude is derived.This paper analyzes the influence of the length of the upper boom hydraulic cylinder on the theoretical digging force of the whole machine when the bucket and stick are digging,which provides a research idea for the analysis of the theoretical digging force of the whole machine.Finally,the Lagrange dynamic equation is established for the working device of the three-arm wheeled hydraulic excavator.In ADAMS software,the working conditions of bucket and stick working alone and compound excavation are simulated,and the stress of each hinge point is analyzed,which proves the reliability of the simulation.