Statistical analysis of the influence of tooth geometry in the performance of a harmonic drive
The objective of this research is to determine the influence of gear tooth geometrical variations in the performance of a double wave harmonic drive through statistical analysis. This work incorporates state of the art analytical and numerical models to evaluate kinematic error, load capacity, bending fatigue strength, and pitting. The geometric variables considered in this study include gear modulus, pressure angle, and tooth correction factor. The statistical analysis follows a three-level full-factorial design of experiments. Nonlinear dynamic simulation is accompanied by finite element analysis to estimate contact and bending stresses. Largest bending fatigue strength is also determined. Results demonstrate that gear modulus is the geometric parameter with prevalent influence on the kinematic error, and pitting life is rather high for all geometric variables considered.
Kinematic performance of planar 5R symmetrical parallel mechanism subjected to clearances and uncertainties
Parallel mechanisms are unavoidably subjected to uncertainties. These uncertainties produce a small variation of link lengths and joints position associated with the clearances. Therefore, this contribution aims at analyzing the effect of these uncertainties on the kinematic performance of the mechanism by examining the kinematic performance atlases. Initially, the complete kinematic model of the mechanism is formulated by considering the uncertainties thar are included in the modeled. The kinematic performance with the uncertainties is computed by using the Monte Carlo method. Then, the kinematic performance atlases based on workspace size and kinematic dexterity are analyzed including the uncertainties. Finally, the kinematic accuracy is evaluated for different link lengths in order to show the correspondent relationship with the kinematic performance atlases.
Frequency selective surface design for blinds applications
In this paper, the reconfigurable blind structure with frequency selective surfaces(FSS) for the building applications are presented. Frequency transmission characteristics for different angles of the proposed blind-FSSs are investigated and verified through simulation and measurement. The simulation results show that we can implement the reconfigurable blind-FSS for multiband wireless applications. To verify the proposed paper, two kinds of blind-FSSs, crossed dipole FSS and circular ring FSS are fabricated and measurements are performed for different angles. The proposed structure in this paper which is very simple, can be easily applied to any planar surface for wireless security applications at low cost.