Design of Super Twisting Integral Sliding Mode Control for Industrial Robot Manipulator

In the present work, integral sliding mode based continuous control algorithm is extended to multi input multi output system. The typical integral sliding mode control (ISMC) contains nominal control with discontinuous feedback control due to which overall control becomes discontinuous in nature. The proposed controller is a fusion of two continuous terms and one of which is able to handle, estimate and reject the disturbance successfully. A proposed robust ISMC technique is applied for industrial robot manipulators which utilizes interactive manipulation activity. Here, robust position tracking control obtained via ISMC principle for two link IRM scheme influenced by parametric uncertainties and external disturbances. The proposed ISMC design replaces the discontinuous part by continuous control, which super twisting control is able to handle the disturbance rejection completely. The effectiveness of the proposed control technique is tested under uncertain conditions and comparison study with other controllers has been done. The simulation result shows that the tracking error is effectively minimized by the proposed technique in presence of uncertain conditions

Long-wave interface instabilities of a two-layer system under periodic excitation for thin films

The stability of a system of two thin liquid films under AC electroosmotic flow is studied using linear stability analysis for long-wave disturbances. The system is bounded by two rigid plates which act as substrate. Boltzmann charge distribution is assumed for the two electrolyte solutions. The effect of van der Waals interactions in these thin films is incorporated in the momentum equations through the disjoining pressure. The base-state velocity profile from the present study is compared with simple experiments and other analytical results. Parametric study involving various electrochemical factors is performed and the stability behaviour is analysed using growth rate, marginal stability, critical amplitude and maximum growth rate in phase space. An increase in the disjoining pressure is found to decrease stability of the system. On the other hand, increasing the frequency of the applied electric field is found to stabilize the system. However, the dependence of the stability on parameters such as viscosity ratio, permittivity ratio, interface zeta potential and interface charge depends not only on the value of individual parameters but also on the rest of the parameters. Design of experiments (DOE) is used to observe the general trend of stability with different parameters.by Abhishek Navarkar, S. Amiroudine, E. A. Demekhin, U. Ghosh and S. Chakrabort

Influence of Formulation Factors on Tablet Formulations with Liquid Permeation Enhancer Using Factorial Design

For a drug with low bioavailability, a matrix tablet with liquid permeation enhancer (Labrasol®) was formulated. Factorial design was used to evaluate the effect of three formulation factors: drug percentage, polymer type (Methocel® K100M or Eudragit® L 100-55), and tablet binder percentage (Plasdone® S-630) on tablet characteristics. Tablets were prepared by direct compression and characterized. Compressibility index values ranged between 15.90% and 29.87% and tablet hardness values from 7.8 to 29.78 Kp. Eudragit®-containing formulations had better compressibility index values with higher tablet hardness. Time for 75% of drug release (T75) was calculated, and formulations containing Eudragit® L 100-55 had faster release rates than tablet formulations with Methocel® K100M. Formulations with Methocel® K100M fit well in the Higuchi model as indicated by their R2 values (>0.98). Among all the formulation factors studied, polymer type displayed the highest and statistically significant effect on compressibility index, tablet hardness, and dissolution rate. Statistical design helped in better understanding the effect of formulation factors on tablet characteristics important for designing formulations with desired characteristics