Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

The existence of geometric errors (misalignment and kinematic errors) and joint clearances is an inherent problem in manipulators. In addition, friction between surfaces and gear backlash errors are unavoidable factors in manipulators using geared motors as their joint actuators. This paper presents a potential solution for the above issues through the application of a dual-loop control scheme. The proposed control scheme uses a redundant feedback strategy, i.e., individual joint displacements (at the joint space level) and, end-effector positions and orientation (at the task space level) are obtained as a feedback signal using appropriate sensors. Using this redundant feedback information, the actual error of the joint displacements are computed and rectified the desired joint space trajectory in joint-space trajectory tracking control to achieve the desired task space trajectory. To demonstrate the effectiveness and show overall performance of the controllers, real-time experiments are performed on an in-house fabricated 2-PRP+1-PPR planar parallel manipulator. The experiment results show that the manipulator tracking performance is significantly improved with the proposed dual-loop control scheme. In addition, the controller parameter sensitivity and robustness analyses are performed. © Springer International Publishing AG 2018.

Department of Mechanical Engineering

World University root node

Mechanisms and Machine Science

Dual-loop motion control for geometric errors and joint clearances compensation of a planar 2-PRP+1-PPR manipulator

The study makes a probabilistic assessment of drought risks due to climate change over the southeast USA based on 15 Global Circulation Model (GCM) simulations and two emission scenarios. The effects of climate change on drought characteristics such as drought intensity, frequency, areal extent, and duration are investigated using the seasonal and continuous standard precipitation index (SPI) and the standard evapotranspiration index (SPEI). The GCM data are divided into four time periods namely Historical (1961–1990), Near (2010–2039), Mid (2040–2069), and Late (2070–2099), and significant differences between historical and future time periods are quantified using the mapping model agreement technique. Further, the kernel density estimation approach is used to derive a novel probability-based severity-area-frequency (PBS) curve for the study domain. Analysis suggests that future increases in temperature and evapotranspiration will outstrip increases in precipitation and significantly affect future droughts over the study domain. Seasonal drought analysis suggest that the summer season will be impacted the most based on SPI and SPEI. Projections based on SPI follow precipitation patterns and fewer GCMs agree on SPI and the direction of change compared to the SPEI. Long-term and extreme drought events are projected to be affected more than short-term and moderate ones. Based on an analysis of PBS curves, especially based on SPEI, droughts are projected to become more severe in the future. The development of PBS curves is a novel feature in this study and will provide policymakers with important tools for analyzing future drought risks, vulnerabilities and help build drought resilience. The PBS curves can be replicated for studies around the world for drought assessment under climate change. © 2018, Springer Science+Business Media B.V., part of Springer Nature.

Department of Civil Engineering

Climatic Change

Probabilistic assessment of projected climatological drought characteristics over the Southeast USA

IoT end-nodes require high performance and extreme energy efficiency to cope with complex near-sensor data analytics algorithms. Processing on multiple programmable processors operating in near-threshold is emerging as a promising solution to exploit the energy boost given by low-voltage operation, while recovering the related frequency degradation with parallelism. In this work, we present a heterogeneous cluster architecture extending a traditional parallel processor cluster with a reconfigurable Integrated Programmable Array (IPA) accelerator. While programmable processors guarantee programming legacy to easily manage peripherals, radio software stacks as well as the global program flow, offloading data-intensive and control-intensive kernels to the IPA leads to much higher system level performance and energy-efficiency. Experimental results show that the proposed heterogeneous cluster outperforms an 8-core homogeneous architecture by up to 4.8× in performance and 4.5× in energy efficiency when executing a mix of control-intensive and data-intensive kernels typical of near-sensor data analytics applications. © 2018 IEEE.

Department of Data Science

Proceedings - IEEE International Symposium on Circuits and Systems

A Heterogeneous Cluster with Reconfigurable Accelerator for Energy Efficient Near-Sensor Data Analytics

SWAT Conference

Uncertainty in the SWAT Model Simulations due to Different Spatial Resolution of Gridded Precipitation Data

Information geometry describes a framework where probability densities can be viewed as differential geometry structures. This approach has shown that the geometry in the space of probability distributions that are parameterized by their covariance matrices is linked to the fundamental concepts of estimation theory. In particular, prior work proposes a Riemannian metric - the distance between the parameterized probability distributions - that is equivalent to the Fisher Information Matrix and helpful in obtaining the deterministic Cram{\'{e}}r-Rao lower bound (CRLB). Recent work in this framework has led to establishing links with several practical applications. However, classical CRLB is useful only for unbiased estimators and inaccurately predicts the mean square error in low signal-to-noise (SNR) scenarios. In this paper, we propose a general Riemannian metric that, at once, is used to obtain both Bayesian CRLB and deterministic CRLB along with their vector parameter extensions. We also extend our results to the Barankin bound, thereby enhancing their applicability to low SNR situations.

Department of Mathematics

IEEE International Symposium on Information Theory - Proceedings

Information Geometric Approach to Bayesian Lower Error Bounds

In this paper, a new family of 3-degree-of-freedom planar parallel manipulators (PPMs), namely U-shape fixed base PPMs starting with an active prismatic joint on each leg, is proposed. In order to identify the best manipulators of this family, comparative kinematic and dynamic performance studies are performed. The kinematic performances are quantified through the local performance index, namely the kinematic isotropy. From the kinematic isotropy analysis results, it is observed that PPR-PRP-PRP, PRP-PRP-PRP and PRR-PRP-PRP configurations have better kinematic design aspects compared to other configurations of this family of U-shape fixed base parallel configurations. Further, from the workspace analysis, it is observed that the PPR-PRP-PRP configuration has a higher value of workspace to the total area required ratio compared to other configurations. This paper also presents a comparative dynamic performance analysis of these top-three U-shape fixed base configurations in terms of dynamic driving performance measures, and energy requirements for three different (fixed base size of the manipulators) aspect ratios under two different loading conditions. From the analyses results, it is perceived that the PRP-PRP-PRP configuration is requiring lower energy and dynamic driving performances than others. These analyses are done with the help of multi-body dynamic software, namely MSC ADAMS, and the results are validated through the help of real-time experiments conducted on in-house fabricated prototypes of these three PPMs. In specific, the energy consumption is measured and compared in this study. Experimental results demonstrated that the PRP-PRP-PRP manipulator displays a considerably better performance in terms of minimum energy requirement. Copyright © Cambridge University Press 2018.

Robotica

Kinematic and dynamic performance investigations of asymmetric (U-shape fixed base) planar parallel manipulators

A new finite-volume flow solver based on the hybrid Cartesian immersed boundary (IB) framework is developed for the solution of high-speed inviscid compressible flows. The IB method adopts a sharp-interface approach, wherein the boundary conditions are enforced on the body geometry itself. A key component of the present solver is a novel reconstruction approach, in conjunction with inverse distance weighting, to compute the solutions in the vicinity of the solid-fluid interface. We show that proposed reconstruction leads to second-order spatial accuracy while also ensuring that the discrete conservation errors diminish linearly with grid refinement. Investigations of supersonic and hypersonic inviscid flows over different geometries are carried out for an extensive validation of the proposed flow solver. Studies on cylinder lift-off and shape optimisation in supersonic flows further demonstrate the efficacy of the flow solver for computations with moving and shape-changing geometries. These studies conclusively highlight the capability of the proposed IB methodology as a promising alternative for robust and accurate computations of compressible fluid flows on nonconformal Cartesian meshes. Copyright © 2017 John Wiley & Sons, Ltd.

International Journal for Numerical Methods in Fluids

A sharp-interface immersed boundary framework for simulations of high-speed inviscid compressible flows

Binary fluid flows distinguished by high-density ratio are of practical importance to many of the engineering applications. Numerical simulations of such flows having sharp discontinuities across the interface is a challenging task and may lead to the generation of spurious velocities if proper care is not taken during discretization. In this regard, we present a consistent and balanced–force algorithm for binary fluid flows with very large density ratios using algebraic volume of fluid technique over three-dimensional hybrid unstructured meshes using a collocated framework. The algorithm emphasizes on the proper force balancing needed at the discrete level and also on the importance of consistent numerical treatment of similar terms across the equations. The efficacy of the formulation is demonstrated through extensive numerical experiments involving strong surface tension and/or gravitational forces. The results clearly indicate the importance of enforcing discrete balance of forces and ensuring consistent treatment of mass and momentum for robust and accurate simulations of multiphase flows. © 2018 Elsevier Ltd

International Journal of Multiphase Flow

A generic algorithm for three-dimensional multiphase flows on unstructured meshes

We present a simple and cost-effective curvature calculation approach for simulations of interfacial flows on structured and unstructured grids. The interface is defined using volume fractions, and the interface curvature is obtained as a function of the gradients of volume fractions. The gradient computation is based on a recently proposed gradient recovery method that mimicks the least squares approach without the need to solve a system of equations and is quite easy to implement on arbitrary polygonal meshes. The resulting interface curvature is used in a continuum surface force formulation within the framework of a well-balanced finite-volume algorithm to simulate multiphase flows dominated by surface tension. We show that the proposed curvature calculation is at least as accurate as some of the existing approaches on unstructured meshes while being straightforward to implement on any mesh topology. Numerical investigations also show that spurious currents in stationary problems that are dependent on the curvature calculation methodology are also acceptably low using the proposed approach. Studies on capillary waves and rising bubbles in viscous flows lend credence to the ability of the proposed method as an inexpensive, robust, and reasonably accurate approach for curvature calculation and numerical simulation of multiphase flows. © 2018 John Wiley & Sons, Ltd.

A cost-effective curvature calculation approach for interfacial flows on unstructured meshes

Particle diameter, particle phase material density and inlet particle volume fraction are three important parameters governing the flow physics of dispersed gas-particle flows. In this work, an inhouse numerical solver is developed to investigate the effects of particle diameter (Stokes number), particle phase material density, inlet particle volume fraction and inlet phase velocities in the flow characteristics of gas-particle flows through vertical and horizontal channels and also in open domains. It is found that, for a constant inlet particle volume fraction, lower diameter particles attain a higher steady state velocity at any section inside the channel than the higher diameter particles; while the corresponding steady state gas velocity at any section increases with increase in particle diameter. On the other hand, for a constant particle diameter, the steady state gas phase velocity at any section decreases with increase in inlet particle volume fraction. Significant changes in both gas and particle velocity and volume fraction profiles have also been observed with inlet slip, i.e., when the velocities of both the phases at inlet are distinct as opposed to being equal, keeping all other flow and physical parameters invariant. © 2018 The Society of Powder Technology Japan