Department of Mechanical Engineering

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Flexibility in curriculum, in all its academic programs, encompassing elements of teaching, research, creativity, innovation and entrepreneurship is the most unique feature of IIT Jodhpur. The Department of Science and Technology (DST), under the National Mission on Cyber Physical Systems, has identified IIT Jodhpur as a Technology &amp; Innovation Hub in the area of Augmented Reality and Virtual Reality. The institute has also been nominated as the coordinator for the Jodhpur City and Knowledge Cluster by the Office of Principal Scientific Adviser, Government of India.

The sprawling 852-acre IIT Jodhpur campus is a majestic tribute to the deep-rooted diverse cultural heritage of the region. The campus is an architectural masterpiece, which is slated to become an international exemplar of sustainability with net-zero energy, and advanced water and waste management strategies.&rdquo;

IIT Jodhpur

Today, Information and Communication Technology (ICT) is ubiquitous. It has touched almost all spheres concerning human survival, growth and development. Agriculture is no exception to it. This paper presents the research initiatives towards improving irrigation efficiency through affordable ICT solutions. It presents experimental results of studies related to improving irrigation efficiency in Semi arid zones in India, using commercially available ICT solutions. It compares between simple microirrigation and microirrigation with ICT (irrigation on demand) and establishes that by using ICT in agriculture, we can increase the irrigation efficiencies by a considerable amount. The paper also presents the development of indigenous wireless sensor node and gateway made from open source hardware and software components. The efforts in this regard show, while maintaining comparable performance, a significant reduction in the cost of wireless sensor devices, when compared to commercially available wireless sensor devices, is achieved. © 2015 IEEE.

World University root node

2015 7th International Conference on Communication Systems and Networks, COMSNETS 2015 - Proceedings

Development of affordable ICT solutions for water conservation in agriculture

In space robots, coupling between the base and the arms causes the floating base to translate and rotate when the arms execute a maneuver, which is typically not seen in earth based robots. Since it is difficult to test developments in space robotics primarily due to the high cost and lack of access to robots in space, it is necessary to have physical systems that can mimic space conditions for experimental validation on earth. Among several options, the use of air bearings to build floating-base robots is one of the most effective. We describe the development of one such system that replicates zero gravity conditions for planar robots. Although similar systems exist elsewhere, the planar dual-arm space robot we have built is distinctive by being relatively lightweight, compact and modular. The setup can be used to test a wide range of experiments such as visual servoing, reactionless maneuvering and object grasping in space. In this paper, the approach taken during the development of both the hardware and software for the experimental setup are discussed. A few results obtained by numerical simulations as well as experimentation are also presented. © 2015 ACM.

ACM International Conference Proceeding Series

Design and development of an earth based experimental setup for testing algorithms on space robots

Singularity of robotic manipulators is an important issue in the stability and control of autonomous robotic systems. This paper presents a real-time dynamic singularity avoidance approach for such autonomous free-floating space robots where visual servoing is used as feedback in the control loop. The proposed method uses manipulability measure as distance criteria and does not require any prior knowledge of singular configurations. Velocities in task space are projected on a surface of constant manipulability measure to avoid singular configurations. Numerical experiments are carried out, to validate the proposed method, on a 6-Degrees-of-Freedom dual-arm space robot mounted on a service satellite. © 2015 ACM.

Real-time dynamic singularity avoidance while visual servoing of a dual-arm space robot

Studying the dynamic behaviour of continuum using discretization through Finite Element is common place. This paper attempts to apply the concept of rigid multibodies connected with proper kinematic pairs to approximate the kinematic behaviour of a flexible body; the system of interconnected rigid multibodies is then used to simulate the deformation pattern of a flexible body under dynamic loading. With this aim, this paper simulates, to begin with, the dynamic behaviour of a simple Cantilevered beam by considering several bar-like rigid multibodies connected by revolute pairs having properly design torsional stiffness to simulate the static deformation pattern under different loading conditions. Later this system is used to find out the dynamic deformation pattern with the help of the software, called ReDySim (Shah et al. in CSTAM Theor Appl Mech Lett 2:063011, 2012 [2]), a multibody dynamic simulation package based on Decoupled Natural Orthogonal Complement (DeNOC) (Saha et al. in Mech Sci 4:1–20, 2013 [1]) concept, in the form of mode shapes and natural frequencies of the system. Next the same model is extended to simulate the dynamic behaviour of a Cantilevered overhung rotor-shaft. The results obtained from ReDySim are compared with those obtained from a MATLAB code written for simulating a formulation based on FEM; a close match between these two dynamics behaviors is obtained to prove the validity of the approach. Thus the rigid multi-body equivalent of a continuum (a structure or a rotor) is built and this is supposed to be useful in simulating dynamic behaviour of continua under generic dynamic conditions. © Springer International Publishing Switzerland 2015.

Mechanisms and Machine Science

Studying continuum dynamic behaviour through rigid multibody dynamics

This is the second of a series of papers devoted to the study of h-p spectral element methods for three dimensional elliptic problems on non-smooth domains. The present paper addresses the proof of the main stability theorem.We assume that the differential operator is a strongly elliptic operator which satisfies Lax-Milgram conditions. The spectral element functions are non-conforming. The stability estimate theorem of this paper will be used to design a numerical scheme which give exponentially accurate solutions to three dimensional elliptic problems on non-smooth domains and can be easily implemented on parallel computers. © Indian Academy of Sciences.

Proceedings of the Indian Academy of Sciences: Mathematical Sciences

h-p Spectral element methods for three dimensional elliptic problems on non-smooth domains, Part-II: Proof of stability theorem

A translating discontinuous-grid-block model for moving boundaries of finite thickness based on multi relaxation time version of LBM has been developed. In this regard, the execution of this model to simulate moving boundary flows has been demonstrated for the cases of a cylinder in simple shear flow, a single rigid wing executing ‘clap and fling’ motion, and the propulsion of a plunging flat plate. It is shown that the implementation of a body fitted refined mesh that moves along with the object improves its resolution and reduces the spurious oscillations registered in the force and velocity measurements compared to a single grid block. A number of interpolation schemes of linear, quadratic and cubic natures are assessed around the discontinuous grid interface. This method is highly suitable for problems that (a) involve large domain sizes in which the moving solid keeps traversing indefinitely in one direction, and (b) a high resolution around the body is demanded without the expenditure of additional computational power and memory as with the stationary discontinuous-grid-block. © 2015, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

22nd AIAA Computational Fluid Dynamics Conference

A shifting discontinuous-grid-block lattice Boltzmann method for moving boundary simulations

The FxLMS is widely used technique in active noise control. In conventional FxLMS, value of convergence coefficient is kept constant which may not be optimum at all frequencies. At some frequencies, convergence speed of FxLMS is slow and at some, it is relatively fast. This leads to significant degradation in performance of FxLMS if characteristics of noise are continuously varying. Normalized FxLMS algorithm is not very effective for continually varying noise. Eigenvalue equalization method may become unstable at some frequencies. Other methods like FxGAL are computationally expensive. The method proposed in this paper attempts to optimally adapt the convergence coefficient of FxLMS algorithm for continually varying noise. It is based on estimating how frequency of noise is varying using fast Fourier transform of reference signal and then, using this information to optimally adapt the convergence coefficient. The optimum value of convergence coefficient depends upon power and phase delay of filtered reference signal. A numerical study of a 3D acoustic cavity shows that the proposed method leads to faster convergence giving higher noise reduction. It also shows that higher the rate of variation of frequency of primary noise, higher is the advantage of the proposed method over the conventional FxLMS algorithm in terms of noise reduction. © 2015 by ASME.

INTER-NOISE 2015 - 44th International Congress and Exposition on Noise Control Engineering

A novel variable step-size filtered-x least mean square algorithm for continually varying noise

This paper addresses the working principal of a sitting/lying type passive lower limb rehabilitation robot (LLRR) where patients legs are connected with a passive serial manipulator(orthoses) which consists of three rotary joints serially connected in a plane (RRR), with an active feedback, driven by a three degrees of freedom (DOF) parallel manipulator looks like a symbol The Lambda. The kinematics of the proposed rehabilitation robot has been presented and discussed. Performance analysis of the proposed robot for basic therapeutic exercises has been analyzed on a virtual prototype with the help of multibody dynamic package (namely MSC ADAMS™) and discussed. © 2015, Indian Institute of Technology, IIT. All rights reserved.

2nd International and 17th National Conference on Machines and Mechanisms, iNaCoMM 2015

Kinematic analysis of a passive sitting/lying type lower limb rehabilitation robot

The mechanical and damage properties of individual constituents used in the fibrous composites are very essential in the micromechanical damage modeling. As fibres are the principal load carrying component of a composite, the knowledge of statistical strength distribution of fibres is very essential for estimating the effective properties of the composite and for its damage investigation. Even though various micromechanical models are available in the literature, most of them disregard the effects of diametric irregularities and variation in properties of the fibres. This may be attributed to the discrepancy between theoretical predictions and experimental results. So, in order to model the uncertainties in composites, the statistical strength distribution of the single fibres should be known a priori. In this work various damage parameters like ultimate strength and failure strains of Torayca R T300 carbon fibres are experimentally characterized for statistical analysis and various probabilistic methods are studied to predict the life data of the fibre in terms of measured stresses. The statistical strength variability of single fibres is described using the Weibull distribution and the probability of failure is predicted. This probabilistic model is developed based on the weakest link hypothesis. Here, the focus of the work is on the reliability characterization of single fibres using a generalized modified four parameter Weibull model having stochastic variables which accounts for geometric irregularities and variation in properties. Finally, the probabilistic estimation of tensile strength given by these models are compared with the experimental results. © 2015, American Institute of Aeronautics and Astronautics. All Rights Reserved.

56th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

Statistical strength determination of carbon fibres using a generalized weibull model

In recent years, the understanding and development of unmanned aerial vehicles has grown exponentially. Although unmanned aerial vehicles have been designed and developed for performing military missions, currently the trend is to extend their applicability to civil missions such as fire fighting, critical infrastructure protection. Department of Science and Technology, Govt. of India initiated a research activity at IIT Kanpur to set up a laboratory for design and development of autonomous mini helicopter. The research activity was grouped under three categories namely mechanical systems, electronics systems and control algorithm and its implementation. This paper describes the newly added on board sensors like miniature radar altimeter, remote engine kill switch and their circuitry to integrate with the existing electronics and also explains the newly designed landing gear for mini helicopter to accommodate the space for payload. The flight data of mini helicopter when it is flown outside with the new onboard sensors, forward facing camera and modified landing gear is also presented in this paper.