| For the past few years, with the rapid development of national economy, the country gives more investment to the aerospace technology and modern machinery processing industry as their projects increasing, on the other hand our demand for large forgings is higher and higher, then the forging workshop of forging mechanization and automation is becoming more and more demanding. Forging manipulator is an important equipment to realize the automation of forging, they are used for holding various kinds of large forgings cooperating with host to finish forging work, which greatly improve the product quality and labor productivity. However, as the domestic core technology of heavy forging manipulator has not yet fully mature, the enterprises need to spend heavily imported from abroad, in order to break the situation, we must be independent innovation to develop our own intellectual property rights of heavy forging manipulator, to meet the needs of all walks of life for large forgings. This article proposes a new type of six-degree-of-freedom forging manipulator from the perspective of mechanism innovation design, and has carried on the comprehensive analysis of the new mechanism and designed its controller.The article followed the studying process of configuration analysis of mechanism,analysis of kinematics, analysis of dynamics, design of controller. Based on the atlas database of planar 12-link 3-DOF topological graph, moreover according to several additional selection principles, which were established by the operating characteristics of face-shovel hydraulic excavators, then a suitable mechanism was elected.First of all, analyze the new type of forging manipulator mechanism, focuses on the synthesis and analysis of the degree of freedom. The mathematic models of kinematics were built based on the complex, as well as the position kinematics analysis, velocity analysis, accelerated velocity speed analysis, jacobian matrix and get position solutions, simulate the kinematics and inverse kinematic model of the mathematic based on MATLAB platform. By contrastive simulation experiments, the correctness of kinematics analyses was verified. Establishing the dynamic model of the major-motion mechanism based on the principle of virtual work in the case of regarding the cylinder and piston of hydraulic cylinder as one component. Make the sine velocity planning on the end of clamp under the three kind of movements, and simulate the dynamics model in the case of the given load. The result shows that the main bearing component of the new forging manipulator is the front lifting hydraulic cylinder. Then compare the dynamic model of the reduced model with the theoretical model which regards the cylinder and piston of hydraulic cylinder as two components, and get the driving force error curve of three hydraulic cylinders of the two models under the condition of three kinds of movements. The reduced model is equivalent to the theoretical model, and it simplifies the dynamics modeling process effectively. The result provides an important theoretical basis for the design and applying of the mechanism. Design the fuzzy PID aimed at three sets of hydraulic cylinders of the new forging manipulator. On this basis, design fuzzy PID controllers to control the hydraulic drive units in order to realize the trajectory tracking of the manipulator clamp. In the process, the control system model is established in the Matlab/Simulink. Under the condition of a given load, the Matlab/Simulink software is used to do manipulator dynamics simulation about the clamp vertical lifting movement, horizontal motion and pitch motion, eventually getting the system unit step response, sine tracking response curve and error curve. The results prove that the fuzzy PID controller can quickly and accurately obtain the parameters of the new forging manipulator’s performance and complete tracking efficiently, allowing the system to maintain a good steady-state performance and dynamic performance. |
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