In order to achieve the manipulator's soft grasp function, the key is to have slip sensors with fine performance. Depending on the elastomer and photoelectric elements installed in the hand, the sensor transforms ...In order to achieve the manipulator's soft grasp function, the key is to have slip sensors with fine performance. Depending on the elastomer and photoelectric elements installed in the hand, the sensor transforms the slippage between the grasped object and the robot's hand to electric signal, thus the slippage can be detected. It will cause elastomers' micro-vibration when the object is slippage. Based on the vibration theory, dynamic theory, light intensity theory and elastic deformation theory, derived is the conclusion that the object's slippage acceleration relativing to the robot's hand has linear relationship with the photoelectric elements' output voltage's differential, and then the model for slippage distinguishing is set up.展开更多
The present paper reports a comparison of experimental SPL spectral data related to the tonal noise generated by axial-flow fans.A nine blade rotor has been operated at free discharge conditions and in four geometrica...The present paper reports a comparison of experimental SPL spectral data related to the tonal noise generated by axial-flow fans.A nine blade rotor has been operated at free discharge conditions and in four geometrical configurations in which different kinds of tonal noise generating mechanisms are present:large-scale inlet turbulent structures,tip-gap flow,turbulent wakes,and rotor-stator interaction.The measurements have been taken in a hemi-anechoic chamber at constant rotational speed and,in order to vary the acoustic source strength,during low angular acceleration,linear speed ramps.In order to avoid erroneous quantitative evaluations if the acoustic propagation effects are not considered,the acoustic response functions of the different test configurations have been computed by means of the spectral decomposition method.Then,the properties of the tonal noise generating mechanisms have been studied.To this aim,the constant-Strouhal number SPL,obtained by means of measurements taken during the speed ramps,have been compared with the propagation function.Finally,the analysis of the phase of the acoustic pressure has allowed to distinguish between random and deterministic tonal noise generating mechanisms and to collect information about the presence of important propagation effects.展开更多
This paper addresses the peristaltic flow of magnetohydrodynamic viscous fluid in an inclined compliant wall channel. Different wave amplitudes and phases ensure asymme- try in the channel flow configuration. Simultan...This paper addresses the peristaltic flow of magnetohydrodynamic viscous fluid in an inclined compliant wall channel. Different wave amplitudes and phases ensure asymme- try in the channel flow configuration. Simultaneous effects of heat and mass transfer are also considered. Viscous dissipation effect is present. The flow and heat transfer are investigated under long wavelength and low Reynolds number assumption. The expres- sions for stream function, axial velocity, temperature and concentration are obtained. The solution expressions for physical quantities are sketched and discussed. It is found that Brinkman and Hartman numbers have reverse effect on the temperature.展开更多
基金National Natural Science Foundation of China(50475060)
文摘In order to achieve the manipulator's soft grasp function, the key is to have slip sensors with fine performance. Depending on the elastomer and photoelectric elements installed in the hand, the sensor transforms the slippage between the grasped object and the robot's hand to electric signal, thus the slippage can be detected. It will cause elastomers' micro-vibration when the object is slippage. Based on the vibration theory, dynamic theory, light intensity theory and elastic deformation theory, derived is the conclusion that the object's slippage acceleration relativing to the robot's hand has linear relationship with the photoelectric elements' output voltage's differential, and then the model for slippage distinguishing is set up.
基金Università di Genova for the financial support to the present work
文摘The present paper reports a comparison of experimental SPL spectral data related to the tonal noise generated by axial-flow fans.A nine blade rotor has been operated at free discharge conditions and in four geometrical configurations in which different kinds of tonal noise generating mechanisms are present:large-scale inlet turbulent structures,tip-gap flow,turbulent wakes,and rotor-stator interaction.The measurements have been taken in a hemi-anechoic chamber at constant rotational speed and,in order to vary the acoustic source strength,during low angular acceleration,linear speed ramps.In order to avoid erroneous quantitative evaluations if the acoustic propagation effects are not considered,the acoustic response functions of the different test configurations have been computed by means of the spectral decomposition method.Then,the properties of the tonal noise generating mechanisms have been studied.To this aim,the constant-Strouhal number SPL,obtained by means of measurements taken during the speed ramps,have been compared with the propagation function.Finally,the analysis of the phase of the acoustic pressure has allowed to distinguish between random and deterministic tonal noise generating mechanisms and to collect information about the presence of important propagation effects.
文摘This paper addresses the peristaltic flow of magnetohydrodynamic viscous fluid in an inclined compliant wall channel. Different wave amplitudes and phases ensure asymme- try in the channel flow configuration. Simultaneous effects of heat and mass transfer are also considered. Viscous dissipation effect is present. The flow and heat transfer are investigated under long wavelength and low Reynolds number assumption. The expres- sions for stream function, axial velocity, temperature and concentration are obtained. The solution expressions for physical quantities are sketched and discussed. It is found that Brinkman and Hartman numbers have reverse effect on the temperature.
