adeel mehmood - Academia.edu (original) (raw)

Papers by adeel mehmood

Strojniški vestnik - Journal of Mechanical Engineering

This article addresses the design and implementation of robust nonlinear control approaches to ob... more This article addresses the design and implementation of robust nonlinear control approaches to obtain the desired trajectory tracking of a flexible joint manipulator driven with a direct-current (DC) geared motor. The nonlinear control schemes have been designed and implemented such that they locally stabilize the closed loop system considering all the states as bounded. The system model has been derived using Euler-Lagrange approach. Two different approaches based on sliding mode control (SMC), i.e. the traditional SMC and integral SMC, have been considered in the present study. To experimentally validate the proposed control laws, an electrically-driven single-link flexible manipulator has been designed and fabricated. The designed control algorithms have been developed and experimentally validated on the custom-developed platform. The results obtained both from MATLAB/Simulink and the experimental platform verify the performance of the proposed control algorithms. Keywords: flexible joint manipulator; modern control system; sliding mode control; integral sliding mode control Highlights • This research presents two approaches to control joint flexibility of a manipulator by considering actuator dynamics. • A mathematical model of the system is derived using Euler-Lagrange algorithm. • Control laws based on SMC and ISMC have been designed to track the desired trajectory. • Based on a custom-developed hardware platform, experimental results are obtained in LabVIEW using NI MyRio-1900. • The obtained results validate the performance of the designed control laws.

2020 14th International Conference on Open Source Systems and Technologies (ICOSST), 2020

Email overload has been an issue for all the email users over the world. In this research we aim ... more Email overload has been an issue for all the email users over the world. In this research we aim to address the issue by devising an intelligent classifier that categories emails into various user defined group using deep learning approaches. We have experimented MLP (Multi-Layer Perceptron) based deep learning approaches for email classification on three datasets of varying size and intent. The experimental results have been tested by varying various parameters like no. of epochs, drop out and hidden dimensions. The tested system has also analyzed the use of various advanced techniques like weight initialization, dropout ratio, use of optimization tools, batch normalization, wherever applicable, to get optimized results. The classifier has various application areas including both domains of industry and academia.

Modeling, simulation and robust control of an electro-pneumatic actuator for a variable geometry ... more Modeling, simulation and robust control of an electro-pneumatic actuator for a variable geometry turbocharger

The choice of technology for automotive actuators is driven by the need of high power to size rat... more The choice of technology for automotive actuators is driven by the need of high power to size ratio. In general, electro-pneumatic actuators are preferred for application around the engine as they are compact, powerful and require simple controlling devices. Specially, Variable Geometry Turbochargers (VGTs) are almost always controlled with electro-pneumatic actuators. This is a challenging application because the VGT is an important part of the engine air path and the latter is responsible for intake and exhaust air quality and exhaust emissions control. With government regulations on vehicle pollutant emissions getting stringent by the year, VGT control requirements have also increased. These regulations and requirements can only be fulfilled with precise dynamic control of the VGT through its actuator. The demands on actuator control include robustness against uncertainty in operating conditions, fast and smooth positioning without vibration, limited number of measurements. Added...

IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, 2017

This paper is concerned with the problem of stabilization and tracking for a class of underactuat... more This paper is concerned with the problem of stabilization and tracking for a class of underactuated systems subjected to external disturbances. Based on the mathematical model of a 4 degrees of freedom (4DOF) ball and plate system, a robust backstepping controller with disturbance rejection is developed. The proposed controller is capable of handling bounded uncertainties with unknown periodicity affecting the control. A comprehensive comparison between linear quadratic regulator (LQR) and the robust backstepping controller is provided, which affirms the superior performance of the proposed control design.

International Journal on Advanced Science, Engineering and Information Technology, 2012

Humanoids 2008 - 8th IEEE-RAS International Conference on Humanoid Robots, 2008

This paper presents the simulation of an eye mechanism by implementing Listingpsilas law. Based o... more This paper presents the simulation of an eye mechanism by implementing Listingpsilas law. Based on these results an eye model has been designed to produce all movements a human eye can have. Saccadic and smooth pursuit movements can be achieved by pan and tilt mechanism while roll movements are also important for VOR, vergence and optokinetic reflexes. Eye plant model

Energy, Apr 1, 2023

In this research work, a Neural Network (NN) and Uniform Robust Exact Differentiator (URED) obser... more In this research work, a Neural Network (NN) and Uniform Robust Exact Differentiator (URED) observer-based Fast Terminal Integral Sliding Mode Control (FTISMC) has been proposed for Oxygen Excess Ratio (OER) regulation of a Polymer Electrolyte Membrane Fuel Cell (PEMFC) power systems for vehicular applications. The controller uses URED as an observer for supply manifold pressure estimation. NN is used to estimate the stack temperature which is unavailable. The suggested control method increased the PEMFC's effectiveness and durability while demonstrating the finite-time convergence of system trajectories. By controlling the airdelivery system in the presence of uncertain current requirements and measurement noise, the approach ensures maximum power efficiency. The Lyapunov stability theorem has been used to confirm the stability of the presented algorithm. In addition, the suggested method eliminated the chattering phenomenon and improved power efficiency. Given these noteworthy characteristics, the research has the potential to decrease sensor dependence and production costs while also improving the transient and steady-state response in vehicular applications.

2019 International Symposium on Recent Advances in Electrical Engineering (RAEE)

With the advancement of technology in Global era, robotics is anticipated as one of the emerging ... more With the advancement of technology in Global era, robotics is anticipated as one of the emerging field of science. Robots are gradually replacing humans and are performing complex tasks which humans are unable to perform. Robotic arm has its importance in heavy industry and in manufacturing processes for optimum results. The main task is to design a system that is capable of controlling a mechanical arm and is able to apply appropriate force to grab the targeted object. The entire robotic arm hardware setup is controlled with National Instruments myRIO-1900 kit in LabVIEW environment. Serial linked robot ED7220C is a five-joints and six degrees of freedom, robotic arm with rigid links. Object detection and classification is performed through a USB camera on LabVIEW in real time. First, the object is detected then according to its dynamic algorithm which classify the shape of object into circular, rectangular and elliptical shapes. Then the coordinate of these objects are provided as input to the robotic arm which can track the object based on the extracted information. Force control is also an essential part in the robot’s control design. Without control a robot may damage the object when it comes in contact with it. A force sensor is used to control the force exerted on the object. Force Sensitive Resistor (FSR) is used to determine the force or pressure that can be applied to the object. The experiments are connected with NI-myRIO-1900 and the FSR mounted inside the gripper of the robotic arm.

2021 International Conference on Artificial Intelligence (ICAI)

This paper demonstrates the detailed derivation of underactuated quadcopter modelling using the L... more This paper demonstrates the detailed derivation of underactuated quadcopter modelling using the Lagrange-Euler/ Newton-Euler equations along with the designing of flight controllers to ensure the stability of both its linear and angular motion during hover condition much more precisely compared to the previous research work. In this research work, a neuro fuzzy based adaptive integral super twisting sliding mode control (SMC) have been simulated in Matlab/Simulink. According to the Lyapunov stability, all signals of a quadcopter system are uniformly ultimately bounded (UUB). Finally the simulation result comparison with an integral backstepping control law exhibit the flexibility and advantages of the proposed nonlinear control technique.

PLOS ONE, 2022

A Polymer Electrolytic Membrane Fuel Cell (PEMFC) is an efficient power device for automobiles, b... more A Polymer Electrolytic Membrane Fuel Cell (PEMFC) is an efficient power device for automobiles, but its efficiency and life span depend upon its air delivery system. To ensure improved performance of PEMFC, the air delivery system must ensure proper regulation of Oxygen Excess Ratio (OER). This paper proposes two nonlinear control strategies, namely Integral Sliding Mode Control (ISMC) and Fast Terminal ISMC (FTISMC). Both the controllers are designed to control the OER at a constant level under load disturbances while avoiding oxygen starvation. The derived controllers are implemented in MATLAB/ Simulink. The corresponding simulation results depict that FTISMC has faster tracking performance and lesser fluctuations due to load disturbances in output net power, stack voltage/power, error tracking, OER, and compressor motor voltage. Lesser fluctuations in these parameters ensure increased efficiency and thus extended life of a PEMFC. The results are also compared with super twisting ...

PLOS ONE, 2021

Emerging applications of autonomous robots requiring stability and reliability cannot afford comp... more Emerging applications of autonomous robots requiring stability and reliability cannot afford component failure to achieve operational objectives. Hence, identification and countermeasure of a fault is of utmost importance in mechatronics community. This research proposes a Fault-tolerant control (FTC) for a robot manipulator, which is based on a hybrid control scheme that uses an observer as well as a hardware redundancy strategy to improve the performance and efficiency in the presence of actuator and sensor faults. Considering a five Degree of Freedom (DoF) robotic manipulator, a dynamic LuGre friction model is derived which forms the basis for design of control law. For actuator’s and sensor’s FTC, an adaptive back-stepping methodology is used for fault estimation and the nominal control law is used for the controller reconfiguration and observer is designed. Fault detection is accomplished by comparing the actual and observed states, pursued by fault tolerant method using redund...

IEEE Access, 2022

In robotic manipulators, feedback control of nonlinear systems with fast finite-time convergence ... more In robotic manipulators, feedback control of nonlinear systems with fast finite-time convergence is desirable. However, because of the parametric and model uncertainties, the robust control and tuning of the robotic manipulators pose many challenges related to the trajectory tracking of the robotic system. This research proposes a state-of-the-art control algorithm, which is the combination of fast integral terminal sliding mode control (FIT-SMC), robust exact differentiator (RED) observer, and feedforward neural network (FFNN) based estimator. Firstly, the dynamic model of the robotic manipulator is established for the n-degrees of freedom (DoFs) system by taking into account the dynamic LuGre friction model. Then, a FIT-SMC with friction compensation-based nonlinear control has been proposed for the robotic manipulator. In addition, a RED observer is developed to get the estimates of robotic manipulator joints' velocities. Since the dynamic friction state of the LuGre friction model is unmeasurable, FFNN is established for training and estimating the friction torque. The Lyapunov method is presented to demonstrate the finite-time sliding mode enforcement and state convergence for a robotic manipulator. The proposed control approach has been simulated in the MATLAB/Simulink environment and compared with the system with no observer to characterize the control performance. Simulation results obtained with the proposed control strategy affirm its effectiveness for a multi-DoF robotic system with model-based friction compensation having an overshoot and a settling time less than 1.5% and 0.2950 seconds, respectively, for all the joints of the robotic manipulator. INDEX TERMS Robotic manipulator, robust exact differentiator, feedforward neural network, fast integral sliding mode control, LuGre friction model, autonomous articulated robotic educational platform. SAFEER ULLAH received the B.S. degree in electronics engineering from International Islamic University, Islamabad, in 2012, and the M.S. and Ph.D. degrees in control and automation from COMSATS University Islamabad, Pakistan, in 2016 and 2021, respectively. He is currently working as an Assistant Monitoring Officer with Khyber Pakhtunkhwa Educational Monitoring Authority. His research interests include analysis, observation, and control of under-actuated nonlinear systems using advanced sliding mode-based control approaches.

2021 International Conference on Robotics and Automation in Industry (ICRAI), 2021

The role of modern control techniques has been instrumental in today's robotic applications becau... more The role of modern control techniques has been instrumental in today's robotic applications because of their increasing requirements for reliability, accuracy, productivity and repeatability. Robotic manipulators are highly non-linear systems with coupled dynamics and thus are vulnerable to a lot of disturbances such as unknown payloads, dynamics that the model and joint friction do not predict. To achieve superior performance and reliability in the presence of friction, this research proposes a robust control algorithm for a five-degree-of-freedom (DoF) robotic manipulator. The dynamic LuGre friction model is used to develop the robot's dynamic model. A sliding mode observer (SMO) is proposed for the estimation of the internal friction state of the LuGre model. The friction and load torque are based on an estimated state to compensate for unidentified friction. A Lyapunov candidate function is used to check the stability of the controller with the SMO. The proposed control methodology has been designed and implemented in MATLAB/Simulink environment to illustrate the tracking of various trajectories. This study's outcomes proved that the proposed control law with model-based friction compensation is effective and efficient.

This paper presents a fixed-time control design for a class of uncertain under-actuated nonlinear... more This paper presents a fixed-time control design for a class of uncertain under-actuated nonlinear systems (UNS) using a non-singular fast terminal sliding mode control (TSMC) with a radial basis function (RBF) based estimator to achieve the fast convergence and robustness against the uncertain disturbances. The generalized mathematical model of the considered class is first reduced into an equivalent regular form, which is more convenient for any control synthesis design. A fast TSMC is designed for the transformed regular form to improve the control performance and annihilate the associated singularity problem of the conventional TSMC scheme. The steering of sliding manifold and system states in fixed-time is ensured through the Lyapunov stability theory. The RBF-based neural networks are used to adaptively estimate the nonlinear drift functions, which are feedbacked to the control input. The theoretical design, analysis and simulations of cart-pendulum and quadcopter systems demon...

Strojniški vestnik – Journal of Mechanical Engineering, 2021

Automation technology has been extensively recognized as an emerging field in various industrial ... more Automation technology has been extensively recognized as an emerging field in various industrial applications. Recent breakthrough in flexible automation is primarily due to deployment of robotic arms or manipulators. Autonomy in these manipulators is essentially linked with the advancements in non-linear control systems. The objective of this research is to propose a robust control algorithm for a five degree of freedom (DOF) robotic arm to achieve superior performance and reliability in the presence of friction. A friction compensation-based non-linear control has been proposed and realized for the robotic manipulator. The dynamic model of the robot has been derived by considering the dynamic friction model. The proposed three-state model is validated for all the joints of the manipulator. The integral sliding mode control (ISMC) methodology has been designed; the trajectories of system every time begin from the sliding surface and it eliminates the reaching phase with assistance ...

ISA Transactions, 2021

In this paper, a robust global fast terminal attractor based full flight trajectory tracking cont... more In this paper, a robust global fast terminal attractor based full flight trajectory tracking control law has been developed for the available regular form which is operated under matched uncertainties. Based on the hierarchical control principle, the aforesaid model is first subdivided into two subsystems, i.e., a fully-actuated subsystem and an under-actuated subsystem. In other words, the under-actuated subsystem is further transformed into a regular form whereby the under-actuated characteristics are decoupled in terms of control inputs. In the proposed design, the nonlinear drift terms, which certainly varies in full flight, are estimated via functional link neural networks to improve the performance of the controller in full flight. Besides, a variable gain robust exact differentiator (VG-RED) is designed to provide us with estimated flight velocities. It has consequently reduced the noise in system's velocities and has mapped this controller as a practical one. The finite-time sliding mode enforcement and the states' convergence are shown, for all flight loops, i.e., forward flight and backward flight, via the Lyapunov approach. All these claims are verified via numerical simulations and experimental implementation of the quadcopter system in a Matlab environment. For a more impressive presentation, the developed simulation results are compared with standard literature.

IEEE Access, 2020

The efficiency and durability of a Proton Exchange Membrane Fuel Cell (PEMFC) can be improved wit... more The efficiency and durability of a Proton Exchange Membrane Fuel Cell (PEMFC) can be improved with proper controller design to regulate the flow of reactants, cell stack temperature and humidity of the membrane. In this paper, sliding mode controllers (SMC) are proposed for a polymer electrolyte membrane fuel cell PEMFC. In particular, first order SMC and second order SMC based on super twisting algorithm are designed and investigated. The actual process has been formulated in simulation by Pukurushpan's ninth order model. Performance of both control laws has been compared in simulation in MATLAB/Simulink environment in terms of oxygen excess ratio, net power generated, stack voltage/power produced and compressor motor voltage. Simulation results dictate that second order SMC demonstrates superior performance in terms of set-point tracking and disturbance rejection. The designed controller makes the interaction of various subsystems in a smooth manner and consequently improves the overall efficiency of the system and prolongs the stack life of the fuel cells. INDEX TERMS Efficiency improvement, oxygen excess ratio, PEM fuel cell, sliding mode control, super twisting algorithm.

Journal of Electrical Engineering & Technology, 2020

This paper presents a backstepping sliding mode control (BSMC) scheme for uncertain underactuated... more This paper presents a backstepping sliding mode control (BSMC) scheme for uncertain underactuated nonlinear systems. Since, underactuated electro-mechanical nonlinear systems (UEMNS) operate under the fewer number of inputs than the degree of freedom, therefore, the control of such systems remains a complex task. In this work, a class of UEMNS is considered which can be transformed into the so-called regular form. In the design process, these UEMNS are first transformed into regular form. In this form, the systems are properly subdivided into series cascaded blocks in which the one of the blocks is indirectly driven by the applied control input whereas the second block is directly controlled by the control input. This structure is apparently suitable for backstepping design. Hence, all the controller steps are designed via the proposed backstepping sliding mode technique. The step by step stability is proved rigorously by considering the Lyapunov approach. In term of benefits, this designed control law provides low-frequency vibration as compared to conventional SMC along with robust performance in the presence of matched uncertainties. This claim is verified via the numerical simulation results of the cart-pendulum system. For further confirmation, these results are also compared with the standard literature results to demonstrate the benefits and effectiveness of the aforesaid control scheme for such class.

International Journal of Control, Automation and Systems, 2020

In this paper, a robust backstepping integral sliding mode control (RBISMC) technique is designed... more In this paper, a robust backstepping integral sliding mode control (RBISMC) technique is designed for the flight control of a quadcopter, which is an under-actuated nonlinear system. First, the mathematical model of this highly coupled and under-actuated system is described in the presence of dissipative drag forces. Second, a robust control algorithm is designed for the derived model to accurately track the desired outputs while ensuring the stability of attitude, altitude and position of the quadcopter. A step by step mathematical analysis, based on the Lyapunov stability theory, is performed that endorses the stability of both the fully-actuated and under-actuated subsystems of the aforementioned model. The comparison of proposed RBISMC control algorithm, with fraction order integral sliding mode control (FOISMC), affirms the enhanced performance in terms of faster states convergence, improved chattering free tracking and more robustness against uncertainties in the system.