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

Limb disability is one of the serious problems and rehabilitation of lower limb requires an assistive force to the patient. A new design for stationary trainer for performing rehabilitation therapies for lower limb at the knee as well as hip joints in the sitting/lying positions is presented in this article. A passive orthosis (similar to an exoskeleton) is suggested in this system to provide a support to lower limb of the patient. The suggested mechanism also comprises of an active Cartesian manipulator based upon a spatial three parallel prismatic–revolute–revolute–revolute kinematic arrangement to perform the required limb therapeutic motions in the transverse/horizontal/lateral and sagittal/longitudinal plane. Numerically, the usefulness of the designed stationary trainer is confirmed using computer-based simulations along with a motion control scheme by performing various clinically suggested therapeutic motion tracking (passive range of motions) tasks. The article demonstrates the accomplishment of the control scheme for various training procedures of the lower limb. © The Author(s) 2022.

World University root node

Department of Mechanical Engineering

International Journal of Advanced Robotic Systems

Design and motion control scheme of a new stationary trainer to perform lower limb rehabilitation therapies on hip and knee joints

Department of Physics

Bulletin of the American Physical Society

Cavity magnonics with van der Waals antiferromagnet

Department of Mathematics

Research in the Mathematical Sciences

Multiplicities and mixed multiplicities of arbitrary filtrations

We report a systematic study on the thermal transport properties of gold nanoparticles (Au NPs) decorated single-layer graphene on a SiO2/Si substrate by the opto-thermal Raman technique. Our results, with moderate Au NPs coverage (<10%), demonstrate an enhancement in the thermal conductivity of graphene by ∼55% from its pristine value and a decrement in the interface conductance by a factor of 1.5. A detailed analysis of our results shows the importance of the photo-thermal conversion efficiency of Au NPs, plasmon-phonon coupling and lattice modifications in the graphene developed after gold nanoparticles deposition in enhancing the thermal conductivity and reducing the interface thermal conductance of the system. Our study paves way for a better understanding of the thermal management in such hybrid systems, which are envisioned as excellent candidates for optoelectronics and photonics applications. © 2022 IOP Publishing Ltd.

Nanotechnology

Investigating the thermal transport in gold decorated graphene by opto-thermal Raman technique

Deep foundations are conventionally being adopted in construction of various structures ranging from bridges to skyscrapers. Bored cast-in-situ piles and drilled shafts have become a common choice of deep foundations, especially in urban areas, owing to the relatively minimal construction associated noise and vibration as opposed to driven pile. However, one of the major shortcomings of bored piles is the lower skin and tip resistances due to the installation effects (stress relief). In the current practice, empirical or semi-empirical correlations are generally adopted for estimating the unit skin friction of bored pile/drilled shafts which is not necessarily taking into account the actual soil state around pile subsequent to the installation. Since the soil state (properties and stresses) in the vicinity of pile will be significantly altered due to the installation processes, studying the evolution of soil state during the various construction stages as well as the loading stage will aid to estimate the residual confining stress and thus the unit skin resistance of pile. This can be made possible using cavity expansion and contraction solutions as the stress relaxation during the excavation of hole is analogous to a cylindrical cavity contraction (unloading) problem and subsequent concrete placement and axial loading resemble a cavity re-loading (i.e. expansion) problem. This paper presents a semi-analytical cylindrical cavity contraction and expansion solution procedure to predict the residual horizontal stress and consequently the skin friction of bored pile. The proposed approach was validated using two well-documented field test data of bored piles/drilled shafts in sand. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

Department of Civil Engineering

Lecture Notes in Civil Engineering

Predicting Residual Stress State Around Bored Cast-In-Situ Piles Utilizing Cavity Contraction and Expansion Solutions

The goal of this work is to develop the next generation of coordinated optimal planning and control schemes for real-world robotic applications, with cost-effective intelligent robots that can safely and robustly perform the tasks at hand. This article presents a dual-loop optimal hierarchical control scheme for robotic manipulators consisting of outer and inner loops. The outer kinematic control loop in the operational space provides a joint velocity reference signal to the inner one. The kinematic control is formulated as a closed-loop optimal control approach to trajectory generation where the desired target (possibly time-varying) is obtained by acting upon the feedback from the actual state of the robot. The kinematic control is obtained using a closed-form analytic solution of the Hamilton-Jacobi-Bellman (HJB) equation. The proposed methodology defines the task in terms of the integral cost function, which results in a global optimal solution. The inner dynamic control loop consists of a neural network (NN)-based adaptive critic (AC) optimal tracking control scheme. The online NN approximator-based dynamic controller learns the infinite-horizon cost function related to inner loop error dynamics in continuous time and calculates the corresponding optimal control input to minimize the cost function forward in time. The stability and the performance of the proposed control scheme are shown theoretically via the Lyapunov approach and also verified experimentally using a 7-DOF Barrett WAM robot manipulator. The warehousing applications of the proposed dual-loop control scheme have been demonstrated experimentally in an exact warehouse setting. Note to Practitioners - This article was motivated by our previous experiences in the Amazon Robotics Challenge (ARC) competitions as a participant. Although the major lessons from those events revealed many important issues toward warehouse automation both from robotic vision and grasping aspects, the application aspects of control engineering to solution for these real-world problems could significantly benefit the today's highly automated society. The intention of this article is to address this situation by designing a cost-effective robot manipulator control scheme by optimizing robot manipulation trajectories in the outer loop along with the actuator input in the inner loop. Therefore, we propose a dual-loop optimal control scheme for robotic manipulations under a cost-optimal framework with guaranteed stability proof via the Lyapunov approach. This results in smoother trajectories with cost-effective control actuator inputs than the state-of-the-art methods. We believe that this work can be beneficial for academic and industrial research to design more advanced and optimized solutions in this domain. © 2004-2012 IEEE.

IEEE Transactions on Automation Science and Engineering

Dual-Loop Optimal Control of a Robot Manipulator and Its Application in Warehouse Automation

The paper discusses a robotic system (RS) for the rehabilitation of the lower limbs of patients. The system consists of an active parallel 3-PRRR robot and a passive part of the RRRR orthoses. A 3D model of a passive RRRR orthosis’s joint structure was developed, taking into account patients’ fit with different anthropological data. The requirements for the body mass index of patients are formulated to optimize the design parameters. This made it possible to determine the rehabilitation system’s workspace, taking into account the minimum and maximum regulation of the passive orthosis joints based on optimization methods. The simulation results are presented. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Mechanisms and Machine Science

Designing a Robotized System for Rehabilitation Taking into Account Anthropological Data of Patients

This paper focuses its attention on investigating the mechanical design and control aspects of a new autonomous mobile agricultural robot being developed for the purpose of automated harvesting of fruits in plantations. The paper goes from discussing the need of automated harvesting of fruits and the problems involved to conceptualizing the design of such a robot and ends with a brief discussion on the control aspects of the robot. © IMechE 2022.

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science

Investigation on design and control aspects of a new autonomous mobile agricultural fruit harvesting robot

Alkali activated binders are sustainable alternatives to carbon-intensive conventional Portland cements. Although earlier studies focussed on the mechanical properties of alkali-activated binders, studies on their carbonation resistance are limited compared to Portland cement systems. Hence, the present study focuses on a systematic review of the carbonation performance of different types of alkali-activated binders, considering all the influencing parameters such as activator modulus, concentration and the nature of the precursor etc. This study also presents a comparison of the carbonation of alkali-activated binders with ordinary Portland cement and blended cement binders. The observations on carbonation resistance are presented in terms of carbonation depth, pH change, compressive strength and corrosion resistance. Moreover, the carbonation products formed in different alkali-activated binder systems and their mineralogical, as well as morphological characteristics are discussed based on the results from the thermogravimetric analysis, X-ray diffraction analysis and scanning electron microscopy. While different polymorphs of calcium carbonate are reported as the carbonated phases in conventional cementitious systems and slag-based alkali-activated binders, nahcolite was found to be the predominant carbonation product when fly ash was used as the precursor. It has also been reported that the intensity of CO2 exposure can result in different forms of carbonate phases in alkali-activated slag, with lower CO2 exposure favouring calcite formation and higher concentrations favouring the formation of vaterite. Matrix densification and crack healing due to carbonation product formation was also observed from the micrographs of carbonated alkali-activated binders, similar to what is reported for conventional cementitious systems. The differential thermogravimetric curves show wide bands in the calcium hydroxide decomposition range in alkali-activated slag binders as opposed to the narrow and distinct lime decomposition peaks in OPC and blended cement systems. The carbonation products are found to change with respect to the carbonation conditions of alkali-activated systems as well as with the type of the precursor. © 2022 Elsevier Ltd

Journal of Building Engineering

Carbonation of alkali activated binders and comparison with the performance of ordinary Portland cement and blended cement binders

Rice straw ash and sugarcane bagasse ash are two of the most abundantly available biomass ashes in India and can be used as supplementary cementitious materials in concrete. Unlike rice husk ash which is also a by-product of rice cultivation, the research studies on the use of rice straw ash as a pozzolan are highly limited. This study characterizes the microstructure of the as-received and processed rice straw ash in comparison with sugarcane bagasse ash. Moreover, the influence of these ashes on the rheological properties of cementitious system was investigated. The microstructural characterization reveals that both rice straw ash and sugarcane bagasse ash are constituted of dumbbell shaped silica-storage structures called phytoliths. Rice straw ash is found to be richer in phytoliths compared to sugarcane bagasse ash. However, the prismatic structures as seen in sugarcane bagasse ash is noticeably absent in rice straw ash. The unburnt carbon content is attributed to the fibrous network present in the ashes. The yield stress and viscosity of cement paste are found to increase with the addition of rice straw ash and sugarcane bagasse ash. Cements blended with sugarcane bagasse ash is found to have a significantly greater viscosity than rice straw ash blended cements at all levels of replacement. Mechanical processing of the ashes (sieving and grinding) to remove the coarse fibrous fraction is found to improve the rheological properties of cement blended with rice straw ash and sugarcane bagasse ash. The optimum dosage of superplasticizer required for rice straw ash and sugarcane bagasse ash blended cements were found to be 0.6% and 0.4%, respectively. © 2022 Elsevier Ltd