H.N. Pishkenari

Sharif University of Technology | SHARIF · Applied Mechanics Division

Continuum robots (CRs) are promising tools for safe interaction with a complex environment. The force caused by the contact of the CR with the obstacles in a cluttered environment can change its shape. To improve the robot’s performance in a constrained environment, an accurate estimation of the contact force and shape of the robot is necessary. To...

In this work, we report our analysis of potential energy surfaces and molecular dynamics studies to characterize the motion of C60, a popular wheel for nanotransporters, on graphene substrates with systematically controlled strains. Our studies reveal that on the verge of 20%, uniaxial strain can increase the activation energy barrier such that it...

Capsule endoscopy is a minimally invasive gastrointestinal diagnostic procedure. The active endoscopic capsule enables the physician to steer the device to any desired position and direction, resulting in a better diagnosis of the disease. Due to the model uncertainties and the existence of disturbances in the gastrointestinal system, traditional c...

Controlling the maneuverability of nanocars and molecular machines on the surface is essential for the targeted transportation of materials and energy at the nanoscale. Here, we evaluate the motion of fullerene, as the most popular candidate for use as a nanocar wheel, on the graphene nanoribbons with strain gradients based on molecular dynamics (M...

Attitude determination in space missions is of a great importance. Especially, small satellite attitude determination faces two main challenges: a limited number of attitude sensors and weak computational resources. The two aforementioned issues represent the main motivation of this work, where a magnetometer and a rate gyro are employed in a simpl...

With the synthesis of nanocar structures the idea of transporting energy and payloads on the surface became closer to reality. To eliminate the concern of diffusive surface motion of nanocars, in this study, we evaluate the motion of C60 and C60-based nanovehicles on graphene and hexagonal boron-nitride (BN) surfaces using molecular dynamics simula...

Modeling and controlling the fuel slosh phenomenon in a satellite is a vital problem in the field of satellite attitude control. In this paper, a satellite with a partially filled spherical fuel tank that uses diaphragm as a propellant management device (PMD), has been considered. The fuel slosh dynamics is modeled by a spherical pendulum with two...

Recently a novel mode of AFM called Trolling-mode AFM (TR-AFM) was developed with the ability to operate in liquid environments with an intrinsically high-quality factor. The presence of chaos in conventional tapping mode AFM severely limits the scanning speed, according to experimental and numerical observations. However, to enhance the scanning s...

Investigation of the nanomachines swarm motion is useful in the design of molecular transportation systems as well as in understanding the assembly process on the surface. Here, we evaluate the...

In this paper, we present an efficient form of Volterra's equations of motion for both unconstrained and constrained multibody dynamical systems that include ignorable coordinates. The proposed method is applicable for systems with both holonomic and nonholonomic constraints. Firstly, based on the definition of ignorable coordinates, one of the mot...

Fast pose estimation (PE) is of vital importance for successful mission performance of agile autonomous robots. Global Positioning Systems such as GPS and GNSS have been typically used in fusion with Inertial Navigation Systems (INS) for PE. However, the low update rate and lack of proper signals make their utility impractical for indoor and urban...

The synthesis of nanocar structures proposes the idea of transporting payloads on the surface. To eliminate the concern of diffusive surface motion of nanocars, in this study, we evaluate the motion of C 60 and C 60 -based nanovehicles on graphene, and hexagonal boron-nitride (BN) surfaces using molecular dynamics simulations and potential energy a...

The high computational costs of atomistic simulations for the investigation of nanostructures, despite their accuracy, necessitate efforts to develop efficient continuum models. Since the classical continuum mechanics assume the matter as continuous and ignore the size dependency of material properties, these theories fail to capture the behavior o...

Recent development in technology and improvement of manufacturing tools have accelerated the use of microrobots (MRs) in numerous areas such as micro sensing and medical applications. The ability to control multiple MRs simultaneously and independently could lead to higher performance, and even make new applications possible. In this paper, we have...

Untethered small-scale robots can accomplish tasks which are not feasible by conventional macro robots. In the current research, we have designed and fabricated a miniature magnetic robot actuated by an external magnetic field. The proposed robot has two coaxial wheels and one magnetic dipole which is capable of rolling and moving on the surface by...

Understanding the motion characteristics of fullerene clusters on the graphene surface is critical for designing surface manipulation systems. Toward this purpose, using the molecular dynamics method, we evaluated six clusters of fullerenes including 1, 2, 3, 5, 10, and 25 molecules on the graphene surface, in the temperature range of 25 to 500 K....

Nanocars have been proposed to transport nanomaterials on the surface. Study of the mechanism of the motion of nanocars has attracted a lot of interests due to the potential ability of these nano-vehicles in the construction of nanostructures with bottom-up approach. Using molecular dynamics simulations, we study the motion of two nano-vehicles nam...

In this study, we investigate the limitations and influence of various factors on the performance of trolling mode atomic force microscopy (TR-AFM). For this purpose, at first, based on the governing equations of motion and using a conventional control method, a simulation tool capable of correctly simulating the imaging procedure in TR-AFM is deve...

Due to significance of high-accuracy attitude control, the fuel sloshing effects on the satellite attitude should be considered, more precisely. This work deals with the attitude control of a liquid propellant-filled satellite considering the incompressible fuel sloshing in the planar maneuver. The satellite consists of a rigid body, a partially-fi...

The failure of mechanical components is a common phenomenon in satellites. This failure can happen in the satellite attitude control system, which causes that the control system of the satellite becomes underactuated. There have been many attempts to control the orientation of underactuated satellites. However, in most studies, the inertia matrix o...

For many years, it has been a significant concern for nanoscience researchers to synthesize nanomachines with steerable motion. Despite the notable number of studies on the motion of nanocars on a surface, the motion characteristics of carbon nanotubes received less attention. Remarkable features such as symmetry, strength, and stiffness made carbo...

Microswimmers have promising applications in different fields, especially in biomedical branches, like microsurgery, therapeutic delivery, and driving sperm cells. Many researchers have proposed different synthetic microrobots with various mechanisms and effective propulsion strategies. Based on the Scallop Theorem, only special sequences of moveme...

In the present study, a novel strategy based on particle motion mode is introduced to control the manipulation process of a bio-particle using trolling mode atomic force microscope. To achieve this goal, the reduced governing partial differential equations and the standard form of the system are used as a model for the system dynamic behavior. The...

Microrobots with their promising applications are attracting a lot of attention currently. A microrobot with a triangular mechanism was previously proposed by scientists to overcome the motion limitations in a low-Reynolds number flow; however, the control of this swimmer for performing desired manoeuvres has not been studied yet. Here, we have pro...

In this study, a nonlinear observer for high-speed estimation of the sample surface topography in a small duration of the probe transient motion utilizing a 2DOF model of TR-AFM is proposed. Since the time duration to reach the steady-state periodic motion of the oscillating probe in conventional imaging methods is relatively high, the proposed non...

Passive magnetic localization is a wireless motion tracking method that can determine position and orientation of objects with embedded magnets. The magnetic field around the magnetic object can be detected using magnetometers. Afterward, using an optimization algorithm, the difference between the measured and calculated magnetic field (from the ma...

Inspired by macroscale vehicles, many molecular machines have been synthesized yet. Due to the importance of atomic manipulation at the surface, nanocars are of particular interest. Nanocar wheels play a crucial role in their motion. One of the popular candidate for using as a nanocar wheel is C60 molecule. In addition, the investigation of nanocar...

Shape memory alloys are referred to as a group of alloys that can retrieve the permanent deformation and strain applied to them and eventually return to their original form. So far, various studies have been done to determine the behavior of these alloys under cyclic loading. Most of the studies have mainly been conducted by using the foundations o...

Microrobots are attracting a lot of interest due to their numerous applications including micro-manipulation and targeted drug delivery. A major challenge in microrobotics is the control of multiple microrobots independently, especially identical microrobots. This paper proposes a novel actuation system for simultaneous planar position control of t...

Swarm motion is an amazing collective behavior in nature for energy saving. Inspiring this natural phenomenon in microorganisms’ swimming, we have proposed a motion strategy for a swarm of microrobots to reduce their energy consumption during path tracking. The investigated microrobot is an artificial Self-Propelled Microswimmer (SPM) with high man...

Designing efficient acoustic stack and elements for high-frequency (HF) medical ultrasound (US) transducers involves various interrelated parameters. So far, optimizing spatial resolution and acoustic field intensity simultaneously has been a daunting task in the area of HF medical US imaging. Here, we introduce optimized design for a 50-MHz US pro...

A Correction to this paper has been published: https://doi.org/10.1007/s11071-021-06256-y

In this study, a novel technique based on adaptive fading extended Kalman filter for atomic force microscopy is proposed to directly estimate the topography of a sample surface without needing any control system. While in conventional imaging techniques, the scanning speed or the bandwidth is limited due to a relatively large settling time, the met...

Capsule endoscopy is a minimally invasive diagnostic technology for gastrointestinal diseases providing images from the human’s digestion system. Developing a robust and real-time localization algorithm to determine the orientation and position of the endoscopic capsule is a crucial step toward medical diagnostics. In this paper, we propose a novel...

In this study, a general 3D distributed modeling of Trolling-Mode AFM (TR-AFM) as a nanorobot is presented to analyze the 2D manipulation process of a spherical cell. To this aim, the analysis is categorized into 3 sections. In the first section, 6 deformations of TR-AFM are taken into account, and the standard model of the system is obtained. More...

This letter discusses the surface-reconstruction-induced self-twisting behavior of Si〈100〉 nanobelts and nanowires (NWs) with rectangular cross section. Giving a thorough physical interpretation, we explain the reason behind this phenomenon and present a continuum-based model. It is revealed that these structures can self-assemble into both right-...

A novel partial differential equation observer is proposed to be used in boundary attitude and vibration control of flexible satellites. Solar panels’ vibrations and attitude dynamics form a coupled partial differential equation–ordinary differential equation system which is controlled directly without discretization. Few feedback signals from boun...

In addition to its biological importance, DPhPC lipid bilayers are widely used in droplet bilayers, study of integral membrane proteins, drug delivery systems as well as patch-clamp electrophysiology of ion channels, yet their mechanical properties are not fully measured. Herein, we examined the effect of the ether linkage on the mechanical propert...

Atomic force microscope (AFM) is one of the most versatile and powerful devices capable of producing high-resolution images of nanomaterial. Many researchers are widely investigating to improve the scanning speed and image quality of AFM by proposing different techniques. Here, we aim to present a novel approach based on the smooth orthogonal decom...

We provide a comprehensive computational characterization of surface motion of two types of nanomachines with four C60 “wheels”: a flexible chassis Nanocar and a rigid chassis Nanotruck. We study the nanocars’ lateral and rotational diffusion as well as the wheels’ rolling motion on two kinds of graphene substrates—flexible single-layer graphene wh...

In this study, we introduce a novel three-dimensional micro-scale robot capable of swimming in low Reynolds number. The proposed robot consists of three rotating disks linked via three perpendicular adjustable rods, actuated by three rotary and three linear motors, respectively. The robot mechanism has an important property which makes it superior...

We have introduced a new low-Reynolds-number microrobot with high 3D maneuverability. Our novel proposed microrobot has a higher rank of the controllability matrix with respect to the previous microswimmers which makes it capable of performing complex motions in space. In this study, governing equations of the microswimmer’s motion have been derive...

Newly synthesized nanocars have shown great potential to transport molecular payloads. Since wheels of nanocars dominate their motion, the study of the wheels helps us to design a suitable surface for them. We investigated C60 thermal diffusion on the hexagonal boronnitride (h-BN) monolayer as the wheel of nanocars. We calculated C60 potential ener...

Trolling mode atomic force microscopy (TR-AFM) can considerably reduce the liquid-resonator interaction forces, and hence, has overcome many imaging problems in liquid environments. This mode increases the quality factor (QF) significantly compared with the conventional AFM operation in liquid; therefore, the duration to reach the steady-state peri...

Molecular machines, such as nanocars, have shown promising potential for various tasks, including manipulation at the nanoscale. In this paper, we examined the influence of temperature gradients on nanocar and nanotruck motion as well as C60 – as their wheel – on a flat gold surface under various conditions. We also compared the accuracy and comput...

Swimming microrobots have a variety of applications including drug delivery, sensing, and artificial fertilization. Their small size makes onboard actuation very hard, and therefore an external source such as the magnetic field is a practical way to steer and move the robot. In this paper, we have designed a novel microrobot steered by magnetic pad...

The main concern in Molecular Dynamics (MD) simulations is the computational cost, and coarse-graining methods accelerate simulations by reducing the degrees of freedom in the system. Yet, the utilization of these methods should be carefully followed. In this paper, we presented an energy-based coarse-graining method for Tersoff and Stillinger-Webe...

The interest to transport properties of nanocars as a function of their structure, fuels further fundamental research with the goal to understand the dynamics of nanomachines on various surfaces at atomistic level. Among the multitude of potential substrates for the nanotransporters, graphene exhibits intrinsic ripples on its surface, which may aff...

نانوماشین‏ها مولکولهایی هستند که با الهام از ماشین های مولکولی طبیعی، طراحی شده و قادر به حرکت و انتقال نانومقیاس هستند. در این مطالعه، نوع خاصی از نانوماشین‏ها با عنوان نانوکامیون، که دارای شاسی صلب و چهار چرخ فولرینی هستند را بررسی می ‏کنیم. بررسی اثر ناهمواری سطحی زیرلایه گرافنی روی حرکت چرخشی و انتقالی نانوکامیون در دماهای مختلف به صورت دینامیک...

Molecular machines and surface rolling molecules show great potential to accomplish different tasks in several fields, such as bottom-up assembly and nano-manipulation. Many researchers have investigated molecular machines, most of which was on a flat single crystal substrate. In this paper, we studied the influence of vacancies in different sizes...

It is well-known that helicopters descending fast may enter the so-called Vortex Ring State (VRS), a region in the velocity space where the blade’s lift differs significantly from regular regions and high amplitude fluctuations are often present. These fluctuations may lead to instability and, therefore, this region is avoided, typically by increas...

In this study, a novel artificial intelligence-based approach is presented to directly estimate the surface topography. To this aim, performance of different artificial intelligence-based techniques, including the multi-layer perceptron neural, radial basis function neural, and adaptive neural fuzzy inference system networks, in estimation of the s...

Attitude and vibration control of a general form of flexible satellites is addressed in this paper. Partial differential dynamic equations are derived considering new details such as multi sectioned solar panels and elastic connections between main hub and solar panels. Boundary control approach is adopted to eliminate simplification errors of disc...

Inspired by macroscale vehicles, many molecular machines have been synthesized yet. Due to the importance of atomic manipulation, nanocars are of particular interest. It has been proven that nanocar wheels play a crucial role in their motion. One of the popular candidate for using as a nanocar wheel is fullerene. In addition the investigation of na...

Attitude control of a satellite having only two reaction wheels is a challenging issue. To address this problem, previously published researches considered some simplifying assumptions on the satellites such as diagonality of the moment of the inertia matrix. On the other hand, in some works, the total angular momentum of the satellite is assumed t...

Dynamic modeling is a fundamental step in analyzing the movement of any mechanical system. Methods for dynamical modeling of constrained systems have been widely developed to improve the accuracy and minimize computational cost during simulations. The necessity to satisfy constraint equations as well as the equations of motion makes it more critica...

We consider magnetic actuation and control of a spherical neutrally buoyant magnetic microrobot via magnetic coil setups and seek to design an optimal controller to reduce the required energy and coils’ currents. We showed that in currently employed setups, where the actuation frequency is few tens of Hertz, the nonlinear dynamics of the system can...

Micro-robots can be used in a wide range of applications such as medical, manufacturing, and military. Nowadays, due to technological problems, studies on micro-robots have been often limited to control of the magnetized micro-particles by an external magnetic field. So, studies on self-propelled micro-robots (with integrated actuators and sensors)...

In the present study, a model was proposed to determine the elastic properties of the family of fullerenes at different temperatures (between 300 and 2000 K) using a combination of molecular dynamics simulation and continuum shell theory. The fullerenes molecules examined here are eight spherical fullerenes, including C60, C80, C180, C240, C260, C3...

In this research, nanoparticle translocation through cell membrane has been studied and simulated. To this end, gold nanoparticles have been selected as the main carrier of the drug and have been functionalized with some selected ligands. The partial charges of the ligands have been calculated using quantum mechanics based on HF technique with 6-31...

In the previous years, a few types of nanocars have been built with the promising potential to transport other molecules, to provide bottom-up assembly, or to perform other mechanical tasks. In this study, we propose a method to convert the diffusive displacement of nanocars to a guided motion in a desired path by adding some impurity atoms in the...

An important issue in the study of the nanostructures behaviors is the surface effects, which increases with the increase of the surface-to-volume ratio. Continuum theories are capable of modeling structures at micro and larger scales with enough precision and low computational costs. However, these theories are unable to predict the mechanical pro...

In this research, nanoparticle translocation through cell membrane has been studied and simulated. To this end, gold nanoparticles have been selected as the main carrier of the drug and have been functionalized with some selected ligands. The partial charges of the ligands have been calculated using quantum mechanics based on HF technique with 6-31...

It is wellknown that helicopters descending fast may enter the so called VRS, a region in the velocity space where the blade's lift differs significantly from regular regions. This may lead to instability and therefore this region is avoided, typically by increasing the horizontal speed. This paper researches this phenomenon in the context of small...

In this study, a novel approach based on a modified Kalman filter algorithm is presented to directly estimate and measure the surface topography of samples by trolling mode atomic force microscopy. Trolling mode atomic force microscopy was introduced as an atomic force microscopy alternative to overcome imaging problems in liquid environments by re...

Nanocars are artificial molecular machines with chassis, axles, and wheels designed for nanoscale transport at materials’ surfaces. Understanding the dependence of surface dynamics of nanocars on the substrate’s physico-chemical properties is critical to design of the transport properties of such man-made nanoscale devices. Among the multitude of p...

By increasing the application of the unmanned aerial vehicles especially quadcopters in nowadays life, the need for having an accurate and reliable simulator for new researches on these robots is felt more. In last decades, many researchers were focussed on quadcopters and their applications and they designed a simulator for checking the output of...