Experimental investigation of feedforward control schemes of a flexible robot manipulator system

This paper presents experimental investigations into the applications of feedforward control schemes for vibration control of a flexible manipulator system. Feedforward control schemes based on input shaping and filtering techniques are to be examined. A constrained planar single-link flexible manipulator is considered in this experimental work. An unshaped bang-bang torque input is used to determine the characteristic parameters of the system for design and evaluation of the input shaping control techniques. The input shapers and filtering techniques are designed based on the properties of the system. Simulation results of the response of the manipulator to the shaped and filtered inputs are presented in time and frequency domains. Performances of the shapers are examined in terms of level of vibration reduction and time response specifications. The effects of derivative order of the input shaper on the performance of the system are investigated. Finally, a comparative assessment of the control strategies is presented and discusse

State of Asian Americans and Pacific Islanders Series

Asian Americans and Pacific Islanders, or AAPIs, are a significant factor in the changing demographics in the United States. But the lack of centralized and accessible data has created a large knowledge gap about this fast-growing and influential group. Data about this group have often not been available or presented in a way that is accessible to policymakers, journalists, and community-based organizations.The Center for American Progress in conjunction with AAPI Data, a project at the University of California, Riverside, have launched a series of reports on the state of the Asian American and Pacific Islanders communities, featuring the most comprehensive research and analysis of its kind for the AAPI population in the United States. The report series will provide an unprecedented look at this community and provide new insight and analysis along various issue areas including: demographics, public opinion, immigration, education, language access and use, civic and political participation, income and poverty, labor market, consumer market and entrepreneurship, civil rights, health care, and health outcomes

Modeling of viscous flows in two-dimensional turbomachinery cascade via viscous-inviscid interaction method

[Abstract]: A two-dimensional time-accurate time-marching viscous flow solver employing the viscous-inviscid interaction method suitable for turbomachinery applications is described. The inviscid main flow solver uses the second-order accurate cellvertex finite-volume spatial discretisation and fourth-order accurate Runge-Kutta temporal integration. The viscous effect due to boundary layer development on the blade surfaces and wakes are modelled using an independent one-dimensional boundary layer subroutine capable of modelling laminar, transition and fully turbulent flows. The solver has been applied to subsonic, transonic and supersonic flow in a cascade of nozzle blades. The results are compared with the experimental data and they showed very good agreemen

The effect of surface reflection and clouds on the estimation of total ozone from satellite measurements

The total amount of ozone in a vertical column is being measured by Nimbus 4 and 7 observations of the intensity of ultraviolet sunlight scattered from the earth. The algorithm for deriving the amount of ozone from the observations uses the assumption that the surface reflects the light isotropically and the albedo is independent of wavelength. The effects of anisotropic surfaces and clouds on the estimate of total ozone are computed for models of the earth-atmosphere system