Jafar Keighobadi

• Doctor of Engineering
• PhD at University of Tabriz

Control of nonholonomic spherical mobile robot is a generalization of the classical ball-plate problem which is still challenging in robotic researches. In this paper, point stabilization of a nonholonomic spherical mobile robot actuated by two internal rotors is investigated. Since every kinematic trajectory is not always dynamically realizable fo...

This paper presents a new immersion and invariance (I&I) observer for inertial microelectromechanical systems (MEMS) sensors-based, low-cost attitude-heading reference systems (AHRSs). Using the I&I methodology, the observer design problem is formulated as finding a dynamics system, called the observer, and a differentiable manifold in the extended...

This paper studies the robust tracking control problem of fully-actuated mechanical systems using a novel integral dynamics surface control (DSC) method. We replace the conventional DSC error surfaces with new nonlinear integral surfaces to generate a quasi-terminal sliding mode (TSM) in the tracking error trajectories. Then, we follow the recursiv...

The main purpose of this paper is design and implementation of a new linear observer for an attitude and heading reference system (AHRS), which includes three-axis accelerometers, gyroscopes, and magnetometers in the presence of sensors and modelling uncertainties. Since the increase of errors over time is the main difficulty of low-cost micro elec...

To avoid the harmful effects of global warming on the earth planet and its atmosphere, the expansion of wind energy consumption based on new control techniques leads to improved energy capacity. The development of wind power plants on the sea is more efficient owing to the stronger wind flows in comparison with the onshore structure. Furthermore, s...

The NSM technique began to apply as a modern technique to treat defects in structural elements and to increase the shear and flexural strength of structural elements. For this technique to be effective, a series of practical experiments were conducted to characterize the behavior of the element strengthened by the NSM technique for flexure and shea...

Since the year 2000, a heightened environmental awareness has led to the emergence of global trends in forefront countries, prompting the need for standardized practices in the environmental building industry. This paper explores various experiments on buildings, demonstrating trends through examinations and tests conducted by governmental or priva...

In light of the complex behavior of vibrating structures, their reliable modeling plays a crucial role in the analysis and system design for vibration control. In this paper, the reverse-path (RP) method is revisited, further developed, and applied to modeling a nonlinear system, particularly with respect to the identification of the frequency resp...

A huge amount of fly ash (FA) was generated every year and dumped in landfills in large quantities and leading to environmental pollution issues. The use of FA in normal concrete and ultra-high performance concrete (UHPC) can reduce pollution in both cases, namely, reduce the accumulation of FA as waste material in landfills and reduce the cement p...

Offshore floating wind turbines (FWT) decrease climate change adversial effects without occupying significant land and harvesting fields. Owing to the earth planet unexpected climate, online adaptive feedback control of FWTs will be effective in the sense of optimal and uniform energy capture. In this paper, a deep reinforcement learning (DRL)-base...

This paper investigates a passivity-based hierarchical SM control (PBHSMC) approach to solve the trajectory tracking issue of a special class of UMSs using unmeasured states and in presence of both unmatched and matched perturbations. First, a passivity-based SM observer (PBSMO) is designed for quick estimation of states in the UMS. Then, we develo...

Cam-follower mechanism efficiency in production of desired motions has been proved along the history of space missions. In this paper, according to pre-specified spatial condition of wide temperature variations between-100 and +120 Celsius degrees, some new and innovative cam-follower profile designs are presented. In the first follower mechanism,...

This article presents a novel geometric framework for the design of extended state observers (ESOs) using the immersion and invariance (I&I) method. The ESO design problem of a class of uncertain lower-triangular nonlinear systems is considered for joint state and total disturbance observation. This problem is formulated as designing a dynamical sy...

In this paper, a novel algorithm for the real-time modeling of the inertial sensor errors is developed based on the genetic algorithm. In the inertial navigation systems, failure to compensate inertial sensor errors not only could result in exponentially increasing of positioning errors, but also leads to loss of precision in the estimation of othe...

In recent years, aided navigation systems through combining inertial navigation system (INS) with global navigation satellite system (GNSS) have been widely applied to enhance the position, velocity, and attitude information of autonomous vehicles. In order to gain the accuracy of the aided INS/GNSS in GNSS gap intervals, a heuristic neural network...

In this paper, the formulation of a block-backstepping control approach is presented to address the trajectory tracking problem for a general class of nonlinear n degrees of freedom (n-DOF) underactuated mechanical systems (UMSs) in nontriangular normal form. First, the Euler-Lagrange model of the general form of UMSs is transformed into block-stri...

In this paper, the integral backstepping sliding mode (IBSM) control with the extended Kalman-Bucy filter (EKBF) to control and state estimation of unmanned aerial vehicles (quadrotor) is provided. In the quadrotor system, the aerodynamic effects of the‏ dynamics of a system are considered, and dynamical equations are derived by the Newton-Euler me...

همترازی در حرکت فرآیندی است که در آن جهت بردارهای سیستم ناوبری اینرسی بر اساس جهات سیستم مرجع در حین حرکت محاسبه می‌شود. همترازی در حرکت با استفاده از داده‌هاي شتاب‌سنج‌ها و ژیروسکوپ‌های واحد اندازه‌گیری اینرسی و داده‌هاي اندازه‌گيري شده توسط سيستم‌هاي کمک ناوبری انجام مي‌گیرد. كه در صورت در دسترس بودن داده‌هاي کمکي امكان همترازی در حال حركت به شکل...

The main challenge of low-cost strap-down inertial navigation systems (SINSs) is time-growing positioning error due to erroneous measurements of micro-electro mechanical system (MEMS)-based inertial sensors. The global navigation satellite system (GNSS) provides drift-free positioning data that can be appropriately utilized to prevent the cumulativ...

This paper discusses a perturbation compensation-based robust vibration controller for single-axis MEMS gyroscope applications. The purpose is to obtain a robust and stable operation mode of the gyroscope and improve its capability in estimating time-varying angular velocities. First, based on the force-balancing operation mode, an estimator is des...

This paper reports an immersion and invariance (I&I)–based robust nonlinear controller for atomic force microscope (AFM) applications. The AFM dynamics is prone to chaos, which, in practice, leads to performance degradation and inaccurate measurements. Therefore, we design a nonlinear tracking controller that stabilizes the AFM dynamics around a de...

This paper reports an extended state observer (ESO)-based robust dynamic surface control (DSC) method for triaxial MEMS gyroscope applications. An ESO with non-linear gain function is designed to estimate both velocity and disturbance vectors of the gyroscope dynamics via measured position signals. Using the sector-bounded property of the non-linea...

Advances in micro-electro mechanical system (MEMS) technology bring about revolutionary changes in au- tonomous vehicle navigation. As a new development, strap-down inertial navigation system (SINS) is effectively combined with global navigation satellite system (GNSS) to construct an integrated SINS/GNSS system. However, time-growing navigation er...

This paper presents a disturbance rejection-based solution to the problem of robust output regulation. The mismatch between the underlying plant and its nominal mathematical model is formulated by two disturbance classes. The first class is assumed to be generated by an autonomous linear system while for the second class no specific dynamical struc...

Advances in Geomatics science and technologies such as global navigation satellite system (GNSS) as well as inertial navigation system (INS) make it possible to develop accurate navigation system relying on low-cost technologies. We concentrated on integrated INS/GNSS system as a significant development in modern navigation systems. The ultimate ai...

Accurate alignment and vertical channel instability play an important role in the strap-down inertial navigation system (SINS), especially in the case that precise navigation has to be achieved over long periods of time. Due to poor initialization as well as the cumulative errors of low-cost inertial measurement units (IMUs), initial alignment is n...

Providing accurate altitude plays a key role in the long-term performance and reliability of inertial Navigation systems (INSs). In low-cost MEMS-grade INSs, failure to compensate vertical channel instability errors could result in exponentially divergence of computed altitude. Therefore, an integrated baro-inertial altimeter comprising of a dampin...

In this paper, an observer-based feedback/feedforward model predictive control (MPC) algorithm is developed for addressing the active vibration control (AVC) of lightly damped structures. For this purpose, the feedback control design process is formulated in the framework of disturbance rejection control (DRC) and a repetitive MPC is adapted to gua...

This paper presents classic and knowledge-based intelligent controllers for regulation of a vibratory MEMS accelerometer. The proposed methods comprise Fuzzy type I (FTI), Fuzzy type II (FTII) and Full-state-feedback (FSF) control systems. An ideal model of sensor under FSF controller is used to generate the required reference data to train if-then...

Due to weak stand-alone accuracy as well as poor run-to-run stability of micro-electro mechanical system (MEMS)-based inertial sensors, special approaches are required to integrate low-cost strap-down inertial navigation system (SINS) with global positioning system (GPS), particularly in long-term applications. This paper aims to enhance long-term...

A GPS-aided Inertial Navigation System (GAINS) is used to determine the orientation‚ position and velocity of ground and aerial vehicles. The data measured by Inertial Navigation System (INS) and GPS are commonly integrated through an Extended Kalman Filter (EKF). Since the EKF requires linearized models and complete knowledge of predefined stochas...

This paper presents a nonlinear disturbance rejection–based controller for the robust output regulation of a triaxial microelectromechanical system (MEMS) vibratory gyroscope. In a MEMS gyroscope, parameter variations, mechanical couplings, suspension system nonlinearities, thermal noise, and centripetal/Coriolis forces are the main uncertainty sou...

The paper aims to develop a new algorithm to enhance the performance of the classic and traditional SINS/GPS navigation systems, particularly in attitude and heading angles estimation. A comprehensive algorithm is designed for utilization of AHRS navigation in the integrated inertial navigation system. State estimation method in the proposed algori...

In recent years, to reduce positioning cost for civil and robotic applications, low-cost inertial sensors, especially Micro Electro Mechanical System (MEMS) types have been produced. Positioning Error of an inertial navigation system comprising low-cost inertial sensors increases due to significant uncertainty of noises, bias and drift of MEMS sens...

Special approaches are required for integration of global navigation satellite system (GNSS) with a strap-down inertial navigation system (INS), particularly based on low-cost micro-electro mechanical system (MEMS)-grade inertial sensors. The proposed approach should be computationally efficient, mathematically nonsingular and executable on small d...

Control of nonholonomic spherical mobile robot is a generalization of the classical ball-plate problem which is still challenging in robotic researches. In this paper, point stabilization of a nonholonomic spherical mobile robot actuated by two internal rotors is investigated. Since every kinematic trajectory is not always dynamically realizable fo...

In this paper, design and implementation of a new algorithm based on model predictive controller, to reduce the height estimation error in the vertical channel of inertial navigation system will be discussed. Vertical channel instability in the inertial navigation systems not only causes the measurement errors increase exponentially with altitude,...

Owing to robust and optimal specification, model predictive control method has received wide attentions over recent years. Since in certain operational conditions, an Atomic/scanning Force Microscope (AFM) shows chaos behavior, the chaos feedback control of the AFM system is considered. According to the nonlinear model of forces interacting between...

Vehicle safety issues and its systems dependence on electronics are rapidly increasing. In intelligent vehicles, rigid components are replaced with controlled x-by-wire systems including configurable electronic elements. In the paper, through complete modeling of Steer-by-wire (SBW) nonlinear dynamics, the chaotic motion of the system is elucidated...

Biomedical applications of swimming microrobots comprising of drug delivery, microsurgery and disease monitoring make the research more interesting in MEMS technology. In this paper, inspired by the flagellar motion of microorganisms like bacteria and also considering the recent attempts in one/two-dimensional modelling of swimming microrobots, a t...

In this paper, the design process of a new model predictive control (MPC) for force-balancing operation mode of a vibratory Micro-Electro-Mechanical-System (MEMS) gyroscope is investigated. Based on the internal model principle, a robust repetitive MPC is proposed to regulate the gyroscope's drive mode output to a pre-specified periodic reference s...

Micro-Electro-Mechanical Systems (MEMS) technology is creating revolutionary changes particularly in medicine. Swimming microrobots can be specified as a kind of miniature biomedical robots which are designed and fabricated applying this technology. In this paper, inspired by microorganism's motion in nature, a three degree-of-freedom flagellar swi...

A combined MEMS Inertial Navigation System (INS) with GPS is used to provide position and velocity data of land vehicles. Data fusion of INS and GPS measurements are commonly achieved through a conventional Extended Kalman filter (EKF). Considering the required accurate model of system together with perfect knowledge of predefined error models, the...

In a strapdown magnetic compass, heading angle is estimated using the Earth's magnetic field measured by Three-Axis Magnetometers (TAM). However, due to several inevitable errors in the magnetic system, such as sensitivity errors, non-orthogonal and misalignment errors, hard iron and soft iron errors, measurement noises and local magnetic fields, t...

Based on dynamical modeling, robust trajectory tracking control of a spherical mobile robot is proposed. The spherical robot is composed of a spherical shell and three independent rotors which act as the inner driver mechanism. Owing to rolling without slipping assumption, the robot is subjected to two nonholonomic constraints. The state space repr...

Biomedical application of swimming microrobots such as controlled drug delivery, microsurgery and diseases monitoring have made the researches conspicuous in MEMS technology. In this paper, inspired by the flagellar motion of microorganisms (i.e. bacteria) in nature, a 3-DOF swimming microrobot is developed and analyzed. The body of the microrob...

Vehicle safety issues and dependence of its numerous systems on electronics are rapidly increasing. As an example, in intelligent vehicles, rigid dynamic components are replaced with controlled x-by-wire systems including dynamically configurable electronic element. In this paper, through complete modeling of steer-by-wire nonlinear dynamics, the c...

This paper presents a MPC (Model Predictive Control) algorithm for MEMS vibratory gyroscopes based on force-balancing control strategy. In the proposed MPC method, using a set of orthonormal basis functions named Laguerre functions, a new prediction and optimization technique is designed. To enhance the capability of proposed MPC method for trackin...

Stoichiometric air-to-fuel ratio (lambda) control plays a significant role on the performance of three way catalysts in the reduction of exhaust pollutants of Internal Combustion Engines (ICEs). The classic controllers, such as PI systems, could not result in robust control of lambda against exogenous disturbances and modeling uncertainties. Theref...

In low-cost Attitude Heading Reference Systems (AHRS), the measurements made by Micro Electro-Mechanical Systems (MEMS) type sensors are affected by uncertainties, noises and unknown disturbances. In this paper, considering the robustness of sliding mode observers against structured and unstructured uncertainties, and also exogenous inputs, the pro...

Tracking precision of pre-planned trajectories is essential for an auto-guided vehicle (AGV). The purpose of this paper is to design a self-constructing wavelet neural network (SCWNN) method for dynamical modeling and control of a 2-DOF AGV. In control systems of AGVs, kinematical models have been preferred in recent research documents. However, in...

The aim of the paper is trajectory tracking control of a non-holonomic mobile robot whose centroid doesn't coincide to its rotation center in the middle of connecting axle of driving wheels. The nonholonomic dynamic model of the Wheeled Mobile Robot (WMR) is developed in global Cartesian coordinates where the WMR's forward and angular velocities ar...

This paper presents a control strategy for micro-electro-mechanical systems (MEMS) z-axis gyroscope, based on the coupling of the fuzzy logic control with the so-called sliding mode control (SMC) approach and sliding mode observer. An adaptive model reference state tracking controller which can estimate the angular velocity vector, and the damping...

Using intelligent robust controllers, perfect trajectory tracking of nonholonomic wheeled mobile robots (WMRs) is developed. A feedback linearizable computed torque controller (FLCTC) may be used to make the convergence of a WMR on preplanned trajectories. Owing to the weak performance against exogenous signals, the FLCTC is replaced by a sliding m...

This paper presents a control strategy for micro-electro-mechanical systems (MEMS) z-axis gyroscope, based on the coupling of the fuzzy logic control with the so-called sliding mode control (SMC) approach and sliding mode observer. An adaptive model reference state tracking controller which can estimate the angular velocity vector, and the damping...

Polyethylene (PE) pipelines with electrofusion (EF) joining is an essential method of transportation of gas energy. EF joints are weak points for leakage and therefore, Nondestructive testing (NDT) methods including ultrasonic array technology are necessary. This paper presents a practical NDT method of fusion joints of polyethylene piping using in...

In a low-cost attitude heading reference system (AHRS), the measurements made by MEMS inertial and magnetic sensors are affected by large parameter uncertainties, stochastic noises and unknown disturbances. In this paper, considering the robustness of the sliding mode observers (SMO) against both structured and unstructured uncertainties as well as...

In this paper, two knowledge based controllers are proposed to overcome the difficulties of a computed torque nonlinear controller (NC) in perfect trajectory tracking of nonholonomic wheeled mobile robots (WMRs). First, the effects of different dynamic models developed in angular and Cartesian coordinate systems are fully examined on the persistent...

This paper presents a control strategy for micro-electro-mechanical systems (MEMS) z-axis gyroscope, based on the coupling of the fuzzy logic control with the so-called sliding mode control (SMC) approach. An adaptive model reference state tracking controller which can estimate the angular velocity vector, and the damping and stiffness model coeffi...

Optimal one-dimensional motion planning of a mobile robot while keeping dynamic grasp is studied. For a mobile robot, as a typical set-up for transportation of object, dynamic grasp problem is defined. It is assumed that the robot moves along a straight path and carries an object on its upper surface and the object should not move relative to the r...

Quasi-static object manipulation using a wheeled mobile robot is studied. For a mobile robot, as a typical set-up for transportation of objects, dynamic grasp problem is defined. It is assumed that the robot moves along a straight path and carries an object on its upper surface and the object should not move relative to the robot (dynamic grasp pro...

Using a proportional-integral sliding surface, a fuzzy adaptive sliding mode controller (SMC) is proposed to control micro-electromechanical systems (MEMS) gyroscopes and estimating the angular rate, damping ratios and stiffness coefficients in real time. The tracking performance of pure adaptive SMC is affected by high range chattering due to mode...

In this paper, a Dynamic Sliding Mode Controller (DSMC) is proposed for trajectory tracking control of a nonholonomic Wheeled Mobile Robot (WMR) in which the centroid doesn't coincide to the connection center of driving wheels. This robust controller is designed based on the developed dynamical model of WMR in Cartesian coordinates, therefore, the...

In this paper, perfect trajectory tracking control of a non-holonomic Wheeled Mobile Robot (WMR) is tackled. First, a Sliding Mode Controller (SMC) is proposed to convergence of WMR on desired position, velocity and orientation trajectories. Due to the weak performance of the SMC against exogenous inputs, a Mamdani-type fuzzy system is designed to...

In a strapdown compass on a vehicle, three-axis magnetometers measure the Earth's magnetic field vector along the body axes of the vehicle to determine its heading angle. Owing to the local magnetic effects, the measurements frequently deviate from the geomagnetic field vector coordinated in the body frame. Therefore, online calibration of the comp...

Purpose – The purpose of this paper is to consider the process of design and implementation of an enhanced fuzzy H∞ (EFH∞) estimation algorithm to determine the attitude and heading angles of ground vehicles, which are frequently affected by considerable exogenous disturbances. To detect the changes of disturbances, a fuzzy system is designed based...

In this paper, perfect trajectory tracking of a non-holonomic Wheeled Mobile Robot (WMR) is developed. The Feedback Linearization (FL) methods may be used to make convergence of WMRs on desired position, and orientation trajectories. Due to the weak performances against exogenous signals, the FL controller is replaced by a Sliding Mode Controller (...

Purpose – The purpose of this paper is to focus on perfect trajectory tracking control of 2 DOF non‐holonomic mobile robots in which the guidance and control commands are imposed through independent driver wheels. Model‐based nonlinear controllers for these robots with unknown parameters require estimation of a specified set of the robot parameters...

In this paper a Fuzzy Tuned extended H ∞ (FTH ∞) estimator is designed and implemented in an Attitude Heading Reference System (AHRS), which is specialized to vehicular applications. In AHRS, 3-axis accelerometers are allotted to measure the earth's gravity field vector and then to update the roll and pitch angles obtained from gyros' dynamic. Ther...