Dynamic modeling of a parallel manipulator（PM） is an important issue. A complete PM system is actually composed of multiple physical domains. As PMs are widely used in various fields, the importance of modeling the ...Dynamic modeling of a parallel manipulator（PM） is an important issue. A complete PM system is actually composed of multiple physical domains. As PMs are widely used in various fields, the importance of modeling the global dynamic model of the PM system becomes increasingly prominent. Currently there lacks further research in global dynamic modeling. A unified modeling approach for the multi-energy domains PM system is proposed based on bond graph and a global dynamic model of the 3-UPS/S parallel stabilized platform involving mechanical and electrical-hydraulic elements is built. Firstly, the screw bond graph theory is improved based on the screw theory, the modular joint model is modeled and the normalized dynamic model of the mechanism is established. Secondly, combined with the electro-hydraulic servo system model built by traditional bond graph, the global dynamic model of the system is obtained, and then the motion, force and power of any element can be obtained directly. Lastly, the experiments and simulations of the driving forces, pressure and flow are performed, and the results show that, the theoretical calculation results of the driving forces are in accord with the experimental ones, and the pressure and flow of the first limb and the third limb are symmetry with each other. The results are reasonable and verify the correctness and effectiveness of the model and the method. The proposed dynamic modeling method provides a reference for modeling of other multi-energy domains system which contains complex PM.展开更多
With the development of fluid-power transmission and control technology,electro-hydraulic-driven technology can significantly improve the load-carrying capacity,stiffness,and control accuracy of stabilization platform...With the development of fluid-power transmission and control technology,electro-hydraulic-driven technology can significantly improve the load-carrying capacity,stiffness,and control accuracy of stabilization platforms.However,compared with mechanically driven platforms,the stiffness and damping of the fluid,as well as the coupling effect between the fluid and the structure need to be considered for electro-hydraulic-driven parallel stabilization platforms,making the modal and dynamic response characteristics of the mechanism more complex.With the aim of solving the aforementioned issues,we research the electro-hydraulic driven 3-UPS/S parallel stabilization platform considering the hinge stiffness.Moreover,the characteristic vibration equation of the mechanism is established using the virtual work principle.Subsequently,the variation characteristics of the natural frequency and the vibration response according to the position of the mechanism are analyzed based on the dynamic equation.Finally,the correctness of the model is verified by a modal test and Runge-Kutta methods.This study provides a theoretical basis for the dynamic design of electrohydraulic-driven parallel mechanisms.展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.51275438,51405421)Hebei Provincial Natural Science Foundation of China(Grant No.E2015203101)
文摘Dynamic modeling of a parallel manipulator（PM） is an important issue. A complete PM system is actually composed of multiple physical domains. As PMs are widely used in various fields, the importance of modeling the global dynamic model of the PM system becomes increasingly prominent. Currently there lacks further research in global dynamic modeling. A unified modeling approach for the multi-energy domains PM system is proposed based on bond graph and a global dynamic model of the 3-UPS/S parallel stabilized platform involving mechanical and electrical-hydraulic elements is built. Firstly, the screw bond graph theory is improved based on the screw theory, the modular joint model is modeled and the normalized dynamic model of the mechanism is established. Secondly, combined with the electro-hydraulic servo system model built by traditional bond graph, the global dynamic model of the system is obtained, and then the motion, force and power of any element can be obtained directly. Lastly, the experiments and simulations of the driving forces, pressure and flow are performed, and the results show that, the theoretical calculation results of the driving forces are in accord with the experimental ones, and the pressure and flow of the first limb and the third limb are symmetry with each other. The results are reasonable and verify the correctness and effectiveness of the model and the method. The proposed dynamic modeling method provides a reference for modeling of other multi-energy domains system which contains complex PM.
基金National Key Research and Development Program of China(Grant No.2019YFB2005303)General Fund of the National Natural Science Foundation of China(Grant No.52175066)+1 种基金Hebei Provincial Natural Science Foundation of China(Grant No.E2020203090)Hebei Provincial Key Science and Technology Projects in the Colleges and Universities of China(Grant No.ZD2022052)。
文摘With the development of fluid-power transmission and control technology,electro-hydraulic-driven technology can significantly improve the load-carrying capacity,stiffness,and control accuracy of stabilization platforms.However,compared with mechanically driven platforms,the stiffness and damping of the fluid,as well as the coupling effect between the fluid and the structure need to be considered for electro-hydraulic-driven parallel stabilization platforms,making the modal and dynamic response characteristics of the mechanism more complex.With the aim of solving the aforementioned issues,we research the electro-hydraulic driven 3-UPS/S parallel stabilization platform considering the hinge stiffness.Moreover,the characteristic vibration equation of the mechanism is established using the virtual work principle.Subsequently,the variation characteristics of the natural frequency and the vibration response according to the position of the mechanism are analyzed based on the dynamic equation.Finally,the correctness of the model is verified by a modal test and Runge-Kutta methods.This study provides a theoretical basis for the dynamic design of electrohydraulic-driven parallel mechanisms.
