Modeling and Control of Flexible Hydraulic Robotic Arm

Abstract

Flexible hydraulic robotic arm is a complicated system which coupled by mechanics and hydraulics. It is widely applied in all kinds of large engineering equipments, such as concrete pump truck, bridge monitor truck, arm frame of crane, etc. The arm system of the hydraulic robotic arm is a multi-body system with redundant freedom, strong nonlinear, coupled with rigid and flexible characters. So it is of great theoretic value and real engineering significance to study the arm system of the robotic arm. In this theme, the movement of flexible hydraulic robotic arm and hydraulic cylinders are seperately analyzed with flexible multi-body dynamics, and the mechanical hydraulic dynamic model of the driving system and the arm system is built with Lagrange Equation and Virtual Work Theory. And the dynamic differential equation is built with the driving force of the hydraulic cylinder as the main force. With the track programming and the optimization method, the dynamic converse problem of the arm end track is researched, so as to get the optimized rotation angle when the arm end reaches the expected point. By using the PD control theory, without decoupling and rank-decreasing, only with feed back from the hydraulic system to realize the close loop control of the arm end position, pose and movement, the relationship between the hydraulic system and the end position & pose is studied, so that the flexible distortion is reduced and the libration is restrained. What’s more, the simulation model of the mechanical arms is built by the dynamic simulation software. The simulation result prove that the movement equation built by this way can clearly describe each dynamic character of the mechanical arms.