In heavy duty machine tools, hydrostatic turntable is often used as a means for providing rotational motion and supporting workpiece, so the accuracy of turntable is crucial for part machining. In order to analyze the...In heavy duty machine tools, hydrostatic turntable is often used as a means for providing rotational motion and supporting workpiece, so the accuracy of turntable is crucial for part machining. In order to analyze the influence of load-indcued errors on machining accuracy, an identification model of load-induced errors based on the deformation caused by applied load of hydrostatic turntable of computerized numerical control(CNC) gantry milling heavy machine is proposed. Based on multi-body system theory and screw theory, the space machining accuracy model of heavy duty machine tool is established with consideration of identified load-induced errors. And then, the influence of load-induced errors on space machining accuracy and the roundness error of a milled hole is analyzed. The analysis results show that load-induced errors have a big influence on the roundness error of machined hole, especially when the center of the milled hole is far from that of hydrostatic turntable.展开更多
Effects of working parameters on performance characteristics of hydrostatic turntable are researched by applying the fluid-structure-thermal coupled model.Fluid-structure interaction(FSI)technique and computational fl...Effects of working parameters on performance characteristics of hydrostatic turntable are researched by applying the fluid-structure-thermal coupled model.Fluid-structure interaction(FSI)technique and computational fluid dynamics(CFD)method are both employed by this new model,and thermal effects are also considered.Hydrostatic turntable systems with a series of oil supply pressures,various oil recess depth and several surface roughness parameters are studied.Performance parameters,such as turntable displacement,system flow rate,temperature rise of lubrication,stiffness and damping coefficients,are derived from different working parameters(rotational speed of turntable and exerted external load)of the hydrostatic turntable.Numerical results obtained from this FSI-thermal model are presented and discussed,and theoretical predictions are in good agreement with the experimental data.Therefore,this developed model is a very useful tool for studying hydrostatic turntables.The calculation results show that in order to obtain better performance,a rational selection of the design parameters is essential.展开更多
This paper is concerned with the H∞ fault detection for continuous-time linear switched systems with its application to turntable systems.The solvability condition for a desired filter is established based on the pro...This paper is concerned with the H∞ fault detection for continuous-time linear switched systems with its application to turntable systems.The solvability condition for a desired filter is established based on the proposed sufficient condition.Based on the double channel scheme of the turntable control system,the turntable system can be modeled as a switched system.Finally,by taking the turntable system as a numerical example,the effectiveness of the proposed theory is well validated.展开更多
With photoelectric tracking system as the research object,based on the theorem of moment of momentum and Euler dynamic equation,Nonlinear biaxial coupling dynamic model of tracking turntable is established.Effects of ...With photoelectric tracking system as the research object,based on the theorem of moment of momentum and Euler dynamic equation,Nonlinear biaxial coupling dynamic model of tracking turntable is established.Effects of moment of inertia coupling,speed coupling and the dynamic coupling between tracking turntable shafts were studied,the analytical relation between them was given in theory.Verify the change trend of theoretical model.And it provides the theory reference and model base,for the future design of the high precision tracking controller And control parameter selection and optimization.In the end,specific measures are made for structure optimization.展开更多
基金Projects(51575010,51575009)supported by the National Natural Science Foundations of ChinaProject(Z1511000003150138)supported by Beijing Nova Program,China
文摘In heavy duty machine tools, hydrostatic turntable is often used as a means for providing rotational motion and supporting workpiece, so the accuracy of turntable is crucial for part machining. In order to analyze the influence of load-indcued errors on machining accuracy, an identification model of load-induced errors based on the deformation caused by applied load of hydrostatic turntable of computerized numerical control(CNC) gantry milling heavy machine is proposed. Based on multi-body system theory and screw theory, the space machining accuracy model of heavy duty machine tool is established with consideration of identified load-induced errors. And then, the influence of load-induced errors on space machining accuracy and the roundness error of a milled hole is analyzed. The analysis results show that load-induced errors have a big influence on the roundness error of machined hole, especially when the center of the milled hole is far from that of hydrostatic turntable.
基金Projects (51175518,51705147) supported by the National Natural Science Foundation of China
文摘Effects of working parameters on performance characteristics of hydrostatic turntable are researched by applying the fluid-structure-thermal coupled model.Fluid-structure interaction(FSI)technique and computational fluid dynamics(CFD)method are both employed by this new model,and thermal effects are also considered.Hydrostatic turntable systems with a series of oil supply pressures,various oil recess depth and several surface roughness parameters are studied.Performance parameters,such as turntable displacement,system flow rate,temperature rise of lubrication,stiffness and damping coefficients,are derived from different working parameters(rotational speed of turntable and exerted external load)of the hydrostatic turntable.Numerical results obtained from this FSI-thermal model are presented and discussed,and theoretical predictions are in good agreement with the experimental data.Therefore,this developed model is a very useful tool for studying hydrostatic turntables.The calculation results show that in order to obtain better performance,a rational selection of the design parameters is essential.
基金supported by the National Natural Science Foundation of China(60804002)the Natural Science Foundation of Heilongjiang Province of China(QC2009C58)+1 种基金the Program for New Century Excellent Talents in Universitythe Chinese National Post-doctor Science Foundation(20090460892)
文摘This paper is concerned with the H∞ fault detection for continuous-time linear switched systems with its application to turntable systems.The solvability condition for a desired filter is established based on the proposed sufficient condition.Based on the double channel scheme of the turntable control system,the turntable system can be modeled as a switched system.Finally,by taking the turntable system as a numerical example,the effectiveness of the proposed theory is well validated.
文摘With photoelectric tracking system as the research object,based on the theorem of moment of momentum and Euler dynamic equation,Nonlinear biaxial coupling dynamic model of tracking turntable is established.Effects of moment of inertia coupling,speed coupling and the dynamic coupling between tracking turntable shafts were studied,the analytical relation between them was given in theory.Verify the change trend of theoretical model.And it provides the theory reference and model base,for the future design of the high precision tracking controller And control parameter selection and optimization.In the end,specific measures are made for structure optimization.
