Journal Articles by Sajid Iqbal
Robotic arm enormous applications can be seen in industries as it is one of the most important ma... more Robotic arm enormous applications can be seen in industries as it is one of the most important manipulator for
development. In this work, a light weight robotic arm is designed. The main factors for the designing of mechanical
prototypes were rigidity of structure, cantilever effect and centre of gravity. To calculate the angles of robotic arm according
to given cartesian position in a short possible time FPGA was used using JTAG protocol. The arduino kit controls the
driving circuit of robotic arm which drives the servo motors according to the given instruction. The basic aim was to design
and practically implement a robotic arm, keeping an eye to reduce the cost by readily available components in the market.
To achieve high walking stability for a passive dynamic walking robot is not easy. In this articl... more To achieve high walking stability for a passive dynamic walking robot is not easy. In this article, we aim to investigate whether the walking performance for a passive dynamic walking robot can be improved by just simply changing the swing ankle angle before impact. To validate this idea, a passive bipedal walking model with two straight legs, two flat feet, a hip joint, and two ankle joints was built in this study. The walking dynamics that contains double stance phase was derived. By numerical simulation of the walking in MATLAB, we found that the walking performance can be adjusted effectively by only simply changing the swing ankle angle before impact. A bigger swing ankle angle in a reasonable range will lead to a higher walking stability and a lower initial walking speed of the next step. A bigger swing ankle angle before impact leads to a bigger amount of energy lost during impact for the quasi-passive dynamic walking robot which will influence the walking stability of the next step.
This article presents a summary of applications of chaos and fractals in robotics. Firstly, basic... more This article presents a summary of applications of chaos and fractals in robotics. Firstly, basic concepts of determin‐ istic chaos and fractals are discussed. Then, fundamental tools of chaos theory used for identifying and quantifying chaotic dynamics will be shared. Principal applications of chaos and fractal structures in robotics research, such as chaotic mobile robots, chaotic behaviour exhibited by mobile robots interacting with the environment, chaotic optimization algorithms, chaotic dynamics in bipedal locomotion and fractal mechanisms in modular robots will be presented. A brief survey is reported and an analysis of the reviewed publications is also presented.
DC-DC converters are widely used in regulated switched mode power supplies and in DC motor drive ... more DC-DC converters are widely used in regulated switched mode power supplies and in DC motor drive applications. There are several sources of unwanted nonlinearity in practical power converters. In addition, their operation is characterized by switching that gives birth to a variety of nonlinear dynamics. DC-DC buck and boost converters controlled by pulse-width modulation (PWM) have been simulated. The voltage waveforms and attractors obtained from the circuit simulation have been studied. With the onset of instability, the phenomenon of subharmonic oscillations, quasi-periodicity, bifurcations, and chaos have been observed. This paper is mainly motivated by potential contributions of chaos theory in the design, analysis and control of power converters, in particular and power electronics circuits, in general.
Like cellular systems-Modular Self-Reconfigurable Robots (MSRR)-accomplish certain tasks through ... more Like cellular systems-Modular Self-Reconfigurable Robots (MSRR)-accomplish certain tasks through coordination of numerous independent modules. At the center of Cellular Automation (CA) is the sliding cube model (SCM) that is a mainstay supporting theoretical developments. Motion constraints of physical modules limit the application of CA method in real robotic systems. This paper proposes a new strategy for implementing CA on MSRR-which is a synergy of CA rules and modular design. Firstly, using the geometric expression of CA rules for SCM, a 2-DOF cube-shaped MSRR module (UBot system) is proposed, which lays the foundation for implementation of unified and highly effective modular locomotion criteria. Secondly, cellular rules are arranged according to the locomotion property of UBot module, and distributed control algorithm is designed for the robot to explore unknown environ-Electronic supplementary material The online version of this article (ments. Simulations results verified this approach with reconfiguration locomotion of UBot robots in diverse unfamiliar environments. Hardware experiment with 16 modules also indicates the physical feasibility of the method.
Articulated caterpillar robot has various locomotion patterns-which make it adaptable to differen... more Articulated caterpillar robot has various locomotion patterns-which make it adaptable to different tasks. Generally, the researchers have realized undulatory (transverse wave) and simple rolling locomotion. But many motion patterns are still unexplored. In this paper, peristaltic locomotion and various additional rolling patterns are achieved by employing sinusoidal oscillator with fixed phase difference as the joint controller. The usefulness of the proposed method is verified using simulation and experiment. The design parameters for different locomotion patterns have been calculated that they can be replicated in similar robots immediately.
Chaos occurs widely in nonlinear dynamical systems. It is an aperiodic behavior in a deterministi... more Chaos occurs widely in nonlinear dynamical systems. It is an aperiodic behavior in a deterministic system that shows sensitive dependence on initial conditions. Chaotic system exhibits apparently random and unpredictable behavior. In a deterministic system starting from an exactly known initial condition we can repeat the sequence of outcomes as many times as we feel like whereas in a random system the sequence of the outcomes cannot be repeated. This new science grounds understanding of order in apparent randomness and simplicity in apparent complexity.
These days computer simulation is very instrumental in education as well as in industry. Circuit ... more These days computer simulation is very instrumental in education as well as in industry. Circuit simulators like Electronic Workbench, Simplorer and PSpice etc. have become essential tools of both undergraduate and graduate courses in basic circuits and electronics courses. PSpice increases the students' abilities to comprehend the behavior of electronic components and circuits. This paper summarizes the usefulness of the PSpice in understanding the operation of electronic components and circuits using a boost regulator and controlled rectifier.
Conference Papers by Sajid Iqbal
ISERD, 2016
Robotic arm enormous applications can be seen in industries as it is one of the most important ma... more Robotic arm enormous applications can be seen in industries as it is one of the most important manipulator for development. In this work, a light weight robotic arm is designed. The main factors for the designing of mechanical prototypes were rigidity of structure, cantilever effect and centre of gravity. To calculate the angles of robotic arm according to given cartesian position in a short possible time FPGA was used using JTAG protocol. The arduino kit controls the driving circuit of robotic arm which drives the servo motors according to the given instruction. The basic aim was to design and practically implement a robotic arm, keeping an eye to reduce the cost by readily available components in the market.
This paper presents a comparative study of the Colpitts oscillator circuit using circuit simulati... more This paper presents a comparative study of the Colpitts oscillator circuit using circuit simulations and experimental results. Different techniques of dynamical systems theory like time series plots, phase portraits and Lyapunov exponents were employed. The time series plots and phase portraits for different state variables of Colpitts oscillator circuit, obtained from PSpice simulation and experimental implementation, were compared with each other. This comparison showed that both the results are identical. It is evident that chaotic Colpitts oscillator exhibited periodic and aperiodic behavior for different values of the circuit parameters.
—Everything in this universe is, to some extent, nonlinear in nature. For certain parameter value... more —Everything in this universe is, to some extent, nonlinear in nature. For certain parameter values, a nonlinear dynamical system exhibits erratic behavior called chaos. In this paper, a novel yet simple method is presented for implementing nonlinear systems using operational amplifiers (op-amps) based circuits like integrators and subtractors. The non-linear function sin 2 (x) has been written in terms of polynomial equation using Taylor series expansion and that polynomial equation has been implemented using op-amps. The transition to chaos has been observed by varying the control parameters in simulations and in experiments.
—Passive dynamic walking (PDW) provides us better insight for understanding human walking, for de... more —Passive dynamic walking (PDW) provides us better insight for understanding human walking, for developing prosthetic limbs and for designing superior bipedal robots. In this paper, we investigated the dynamics of a simple PDW, 2D compass-gait biped model that loosely look like human legs (without knees), using time-series analysis based on nonlinear dynamics. Previously, this passive biped model has been explored using only bifurcation diagrams and phase-space plots, but we studied it using nonlinear time-series analysis. The experimental results from walking experiments of prototype passive compass-gait biped validated the simulation results. These results can be useful for designing efficient bipedal robots.
—Few trends in education in the last century match the sudden onset of Massive Open Online Course... more —Few trends in education in the last century match the sudden onset of Massive Open Online Courses (MOOCs). The modern MOOC movement started in late 2011, when the first standard MOOC was launched. In few years, MOOCs have received immense coverage in media, academia and industry. MOOCs have established one of the key facts that education is no longer a privilege but a basic right. Students can learn any imaginable subject from the world's top professors and industry experts. Massive online courses have also increased interest in online learning. Current online learning is a classic disruptive innovation as it is economical and of high quality. The main aim of this paper is to analyze the state of the art in MOOCs since the IEEE CS Report 2022 was made public.
Since its inception in 1989, World Wide Web has been reshaping the idea of open learning. But in ... more Since its inception in 1989, World Wide Web has been reshaping the idea of open learning. But in the field of distance education, Massive Open Online Courses (MOOCs) are the latest innovation. This paper presents concepts of chaos theory for developing a framework for this rapidly emerging form of online learning in general and engineering education in particular. The metaphors of chaos theory can be used in education because a MOOC classroom is a complex dynamical system. The authors find the metaphors of deterministic chaos like sensitive dependence on initial conditions, nonlinearity, and complexity relevant to teaching and learning MOOCs.
Many research groups developed bifurcation diagrams, Poincare maps and computed Feigenbaum consta... more Many research groups developed bifurcation diagrams, Poincare maps and computed Feigenbaum constants for passive walkers. Very few attempts have been made for performing nonlinear time-series analyses of these complex dynamical systems. Besides, Garcia’s et al.’s the simplest walking model, the compass-gait biped model is the most commonly used passive dynamic walking (PDW) biped robot by the biomechanists, robotics engineers and chaos theorists. We accomplished nonlinear analysis of a time-series generated by the compass-gait biped and aimed to examine its dynamical behavior. The walking gait time-series data presented chaotic dynamics as fractal dimensions and positive Lyapunov exponents were found.
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Journal Articles by Sajid Iqbal
development. In this work, a light weight robotic arm is designed. The main factors for the designing of mechanical
prototypes were rigidity of structure, cantilever effect and centre of gravity. To calculate the angles of robotic arm according
to given cartesian position in a short possible time FPGA was used using JTAG protocol. The arduino kit controls the
driving circuit of robotic arm which drives the servo motors according to the given instruction. The basic aim was to design
and practically implement a robotic arm, keeping an eye to reduce the cost by readily available components in the market.
Conference Papers by Sajid Iqbal
development. In this work, a light weight robotic arm is designed. The main factors for the designing of mechanical
prototypes were rigidity of structure, cantilever effect and centre of gravity. To calculate the angles of robotic arm according
to given cartesian position in a short possible time FPGA was used using JTAG protocol. The arduino kit controls the
driving circuit of robotic arm which drives the servo motors according to the given instruction. The basic aim was to design
and practically implement a robotic arm, keeping an eye to reduce the cost by readily available components in the market.
continually reshaping the notion of open learning. Massive Open Online Courses (MOOCs) have generated a paradigm shift in online education by presenting free high-quality education to anyone, anywhere with Internet access. Since 2012, MOOCs got attention of the universities, media and entrepreneurs. These online courses may change the world by 2022. This paper discusses major elements of MOOCs that can influence teaching and learning in engineering. It also explores the promise of online education in improving standard in-class engineering education.