Simulation And Evaluation Of Compliance Process For Forging Manipulator

The key factor for assuring that the manipulator can work in good conditions is the ability of forging manipulator to comply with heavy and unpredictable loads. In order to evaluate effectively the influence of compliance movement for the forging manipulator, a multi-disciplinary modeling for describing the compliance movement during one forging process has been established so as to analyze the significance of compliance. Based on the analysis of compliance characteristics, the passive compliance indices of robot manipulator have been proposed and the passive compliance ability of the forging manipulator has been evaluated by these indices, which provides the theoretical basement for both the design and optimization of the forging manipulator.In order to describe the compliance movement of forging manipulator effectively during one forging process, a multi-disciplinary dynamic modeling of forging manipulator including forging, mechanism and hydraulic subsystems has been established. Based on the modular approach, the forging subsystem, mechanism subsystem and hydraulic subsystem have all been expressed in state space equations, which can form the coupling dynamic model by defining the input and output relations among subsystems. The model is utilized to describe and analyze the compliance process and the characteristics for two periods of compliance have been revealed, that is: two degrees of freedom active compliance stage and three degrees of freedom active and passive compliance stage. Because of the different topology of the mechanism subsystem during two stages, the global simulation method based on the proposed idea of the"Replacement of Local Modeling Units"can realize the automatic simulation process. The simulation results show that the compliance movement will protect the manipulator from being damaged by large load, which has great significance for assuring that the manipulator can work in good conditions. In order to evaluate effectively the compliance ability of the forging manipulator, passive compliance indices of general robot manipulator have been established to evaluate the buffering ability under extreme conditions. According to the proposed indices, a robot manipulator is divided into two parts: compliance structure and protected structure. The compliance structure consisting of flexible elements, damping and topology-varying mechanism is used to comply with the heavy external loads while the protected structure consisting of rigid elements with settled topology is the protection goal of the compliance structure. Two indices are proposed based on the energy distribution between these two parts: Static Passive Compliance Index (SPCI) which reveals the ratio of the energy distributed in the compliance structure to the whole system under a specified configuration and Kineto-static Passive Compliance Index (KPCI) which reflects the energy distribution of the robot manipulator to buffer external loads along a predefined trajectory. Based on these indices, the compliance movement has been evaluated and the characteristics of the compliance method have been analyzed, which demonstrate the invariance of the indices.The simulation and evaluation of the compliance process for the forging manipulator in this thesis offer the optimization goal and design principle for the future forging manipulator.