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robotic-systems
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Modelling and Control of Swarm Robotic Systems with Multiple Ground and Aerial Clusters under an Imperfect Network
, Ph.D. Dissertation Sharif University of Technology ; Alasty, Aria (Supervisor)
Abstract
In this study, an effective collective control strategy is presented for the decentralized behavior control of a heterogeneous multi–cluster swarm robotic system composed of a group of quadrotors as aerial agents, and a group of two–wheeled mobile robots as ground agents. In this regard, first of all, a new element for swarm robotic systems is introduced. This element, which is made up of a portion of swarm members and encircles the whole swarm, is called the shell element. An algorithm for developing the shell element in swarm robotic systems composed of agents moving in the two–dimensional space is established. Subsequently, inspired by the thermodynamic science and based on the introduced...
Two-Level Intelligent Control of Multiple Robotic Arms
, Ph.D. Dissertation Sharif University of Technology ; Sadati, Naser (Supervisor)
Abstract
This thesis presents a fuzzy-based interaction prediction approach (F-IPA) for two-level optimal control of large-scale systems. The design procedure uses a decomposition/coordination framework of hierarchical structures. At the first level, the system is decomposed into subsystems for which subproblems are formed. At the second level, a fuzzy coordinator is used to predict the coordination parameters needed to coordinate the solutions of the first level subproblems. The fuzzy coordinator uses a critic vector to evaluate its performance and learn its parameters by minimizing an energy function. The proposed control scheme is implemented on a two-degrees-of-freedom (2DOF) model of robot...
Mechanical Systems Using Nonlinear State Feedback
, M.Sc. Thesis Sharif University of Technology ; Namvar, Mehrzad (Supervisor)
Abstract
Disturbance is one of the inseparable components of the mechanical systems which cannot be avoided. In these systems a number of inner and outer sources exist which are the cause of disturbance. Abrupt changes in torque, uncertainty in parameters, mechanical impulses and external forces on robot’s parts all can be mentioned as examples which introduce disturbance that affects the output of mechanical and robotic systems. Therefore, disturbance rejection is considered indispensable in robotic control systems. There are number of problems which are associated with disturbance rejection. In several methods, mostly optimization based methods, system fails to completely reject the disturbance and...
Optimal Multi-agent Formation Control of Quadcopters
, M.Sc. Thesis Sharif University of Technology ; Rezaeizadeh, Amin (Supervisor)
Abstract
In today's world, mobile robots have many applications in defense, transportation and industry. A robot may not be able to handle a mission alone or there may be different roles to perform a mission that a robot alone cannot perform, so the need to work with team robots is felt to the Necessary that by development Robot Technology and Advances in Communication, Microelectronics, Computing Technology, and Multi - Factor Expansion, robotic systems are widely used in theoretical research due to their flexibility, robustness, and scalability. In this research, robots are controlled in a coordinated manner as a team. In this research, algorithms were developed so that in a two and...
Hardware in the loop simulation and analysis of a model of fish robotic system
, Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 12 July 2010 through 14 July 2010, Istanbul ; Volume 5 , 2010 , Pages 203-210 ; 9780791849194 (ISBN) ; Vosoughi, G. R ; Farshchi, M ; Nemati, A ; Sharif University of Technology
2010
Abstract
In the present study, an adaptive sliding mode control method was employed to control a fish robotic system using hardware in the loop methodology. Up to now, few researches have focused on autonomous control of fish robot in dynamic environments which may be the result of difficulties in modeling of hydrodynamic effects on fish robot. Therefore, following the introduction of the nonlinear model for the robot, elongated body theory, suggested by Lighthill, was used to analyze fish movements. Then, kinematics control to track desired trajectories was designed for under-actuated model of robot. Adaptive sliding mode controller, capable of adapting according to changes and uncertainties, was...
Deployment of multi-agent robotic systems in presence of obstacles
, Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 12 July 2010 through 14 July 2010, Istanbul ; Volume 5 , 2010 , Pages 7-12 ; 9780791849194 (ISBN) ; Sayyaadi, H ; Sharif University of Technology
2010
Abstract
The deployment of multi-agent systems in presence of obstacle deals with autonomous motion of agents toward a specified target by sensing each other and boundaries of obstacles. In this paper, asynchronous, scalable, distributed algorithm is used to deploy agents. Boundaries of obstacles are modeled by virtual agents. Algorithm was implemented by solving continuous n-median problem called generalized Fermat-Weber problem. It is shown that deployment is performed when position of real agents are the geometric median of their Voronoi cells. Simulation results show the validity of the proposed algorithm very well
Nonlinear robust adaptive Cartesian impedance control of UAVs equipped with a robot manipulator
, Article Advanced Robotics ; Volume 29, Issue 3 , Feb , 2015 , Pages 171-186 ; 01691864 (ISSN) ; Sayyaadi, H ; Sharif University of Technology
Robotics Society of Japan
2015
Abstract
In this paper, a new nonlinear robust adaptive impedance controller is addressed for Unmanned Aerial Vehicles (UAVs) equipped with a robot manipulator that physically interacts with environment. A UAV equipped with a robot manipulator is a novel system that can perform different tasks instead of human being in dangerous and/or inaccessible environments. The objective of the proposed robust adaptive controller is control of the UAV and its robotic manipulators end-effector impedance in Cartesian space in order to have a stable physical interaction with environment. The proposed controller is robust against parametric uncertainties in the nonlinear dynamics model of the UAV and the robot...
Tele-echography of moving organs using an Impedance-controlled telerobotic system
, Article Mechatronics ; Volume 45 , 2017 , Pages 1339-1351 ; 09574158 (ISSN) ; Salarieh, H ; Behzadipour, S ; Tavakoli, M ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
A novel impedance-controlled teleoperation system is developed for robot-assisted tele-echography of moving organs such as heart, chest and breast during their natural motions (beating and/or breathing). The procedure of devising the two impedance models for the master and slave robots is developed such that (a) the slave robot holding the ultrasound (US) probe follows the master trajectory but complies with the oscillatory interaction force of the moving organ, and (b) the sonographer receives feedback from the non-oscillatory portion of the slave-organ interaction force via the master robot similar to the haptic feedback received in echography of a stationary organ. These goals are...
Prescribed-Time control for perturbed euler-lagrange systems with obstacle avoidance
, Article IEEE Transactions on Automatic Control ; Volume 67, Issue 7 , 2022 , Pages 3754-3761 ; 00189286 (ISSN) ; Assadian, N ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
This article introduces a class of time-varying controllers for Euler-Lagrange systems such that the convergence occurs at an arbitrary finite time, independently of initial conditions, and free of chattering. The proposed controller is based on a mapping technique and is designed in two steps: First, a conventional (obstacle avoidance) asymptotically stable controller is specified for the nominal system; then, by a simple substitution, a prescribed-time (obstacle avoidance) controller is achievable for the perturbed system. It is proved that the proposed scheme is uniformly prescribed-time stable for unperturbed systems and prescribed-time attractive for perturbed systems as it rejects...
Adaptive impedance control of UAVs interacting with environment using a robot manipulator
, Article 2014 2nd RSI/ISM International Conference on Robotics and Mechatronics, ICRoM 2014 ; Oct , 2014 , p. 636-641 ; Sharifi, M ; Sharif University of Technology
Abstract
In this paper, a nonlinear adaptive impedance controller is proposed for UAVs equipped with a robot manipulator that interacts with environment. In this adaptive controller, by considering the nonlinear dynamics model of the UAV plus the robot manipulator in Cartesian coordinates, all of model parameters are considered to be completely uncertain and their estimation is updated using an adaptation law. The objective of the proposed adaptive controller is the control of manipulator's end-effector impedance in Cartesian coordinates to have a stable physical interaction. The adjustable Cartesian impedance is a desired dynamical relationship between the end-effector motion in Cartesian...
Adaptive control of robot manipulators including actuator dynamics and without joint torque measurement
, Article 2010 IEEE International Conference on Robotics and Automation, ICRA 2010, Anchorage, AK, 3 May 2010 through 7 May 2010 ; 2010 , Pages 4639-4644 ; 10504729 (ISSN) ; 9781424450381 (ISBN) ; Namvar, M ; Sharif University of Technology
2010
Abstract
Ignoring actuator dynamics in control of rigid manipulators can in practice result in performance degradation or loss of system stability. However, consideration of actuator dynamics usually requires measurement of robot joint torques. This paper addresses motion tracking control of an n-DOF rigid robot by taking into account its actuator dynamics. Joint torque measurement is avoided by using an adaptive observer. The backstepping technique is adopted to develop a dynamically smooth adaptive nonlinear controller dealing with uncertainties in manipulator and actuator dynamics. Semi-global convergence of motion tracking errors as well as torque estimation error are proven without any...
Investigation on dynamic modeling of SURENA III humanoid robot with heel-off and heel-strike motions
, Article Iranian Journal of Science and Technology - Transactions of Mechanical Engineering ; Volume 41, Issue 1 , 2017 , Pages 9-23 ; 22286187 (ISSN) ; Yousefi Koma, A ; Khadiv, M ; Mansouri, S ; Sharif University of Technology
Shiraz University
2017
Abstract
The understudy SURENA III humanoid robot was designed and fabricated at the Center of Advanced Systems and Technologies (CAST) located in the Universityof Tehran. In this paper, a full dynamic model of SURENA III in different walking phases including heel-offand heel-strike motions is presented. To this end, first a trajectory planning method based on robot kinematics is introduced. Then, the multi-body dynamics of the robot links are calculated using Lagrange and Kane approaches which are then verified. In this model, the power transmissionsystem is considered to be ideal. Afterward, system identification routine is adopted to model the dynamic behavior of the power transmission system. By...
Decentralized impedance control of nonredundant multi-manipulator systems
, Article 2008 IEEE International Conference on Networking, Sensing and Control, ICNSC, Sanya, 6 April 2008 through 8 April 2008 ; 2008 , Pages 206-211 ; 9781424416851 (ISBN) ; Ghaffarkhah, A ; Sharif University of Technology
2008
Abstract
In this paper, we propose a decentralized control scheme for combined motion/force control of nonredundant multi-manipulator robotic systems, cooperatively grasping a rigid body in a prespecifled position/force trajectory. The proposed control scheme uses the impedance method for modeling the internal force exerted by the end effectors to the object. The precise mathematical analysis of the overall dynamical system and the proposed controller are presented and the stability of the overall system is studied. The proposed controller, then, is applied to a cooperative system composed of two PUMA560 manipulators and the simulation results are presented to verify the proposed control scheme
A new approach for optimal control of multiple- Arm robotic systems
, Article IFAC Proceedings Volumes (IFAC-PapersOnline) ; Volume 16 , 2005 , Pages 313-318 ; 14746670 (ISSN); 008045108X (ISBN); 9780080451084 (ISBN) ; Babazadeh, A ; Sharif University of Technology
IFAC Secretariat
2005
Abstract
Optimal control frameworks are very important in optimization of multiple-arm robotic systems, although complexity, non-linearity and having large scales usually cause some computational problems in the capacity and time needed. in this paper, it is shown how by conducting the study of multiple-arm robotic systems, within a decomposition-coordination framework, the overall optimum can be achieved in only a few iterations. By using this methodology, the overall problem is considered as optimization of a two-level large-scale system. So with the aim of optimization, the problem is first decomposed into m sub-problems at the first level, where each sub-problem is solved using a typical gradient...
Robust decentralized position/force control of cooperative robots without velocity measurement
, Article 2005 IEEE International Conference on Industrial Technology, ICIT 2005, Hong Kong, 14 December 2005 through 17 December 2005 ; Volume 2005 , 2005 , Pages 1403-1408 ; 0780394844 (ISBN); 9780780394841 (ISBN) ; Elhamifar, E ; Sharif University of Technology
2005
Abstract
A decentralized control scheme for multiple cooperative manipulators system is developed to achieve the desired performance in motion and force tracking in the presence of uncertainties in the dynamic equations of the robots. To reduce the effects of uncertainties in the closed-loop performance, a robust control algorithm using a robustifying term is proposed. Based on the Lyapunov stability method, it is proved that all the signals in the closed-loop, composed of a robot, an observer and a controller are uniformly ultimately bounded. Also to avoid the difficulties of using velocity sensors within the hand architecture an output feedback control scheme with a linear observer is used. © 2005...
Optimization of kinematic redundancy and workspace analysis of a dual-arm cam-lock robot
, Article Robotica ; Volume 34, Issue 1 , 2016 , Pages 23-42 ; 02635747 (ISSN) ; Ghaemi Osgouie, K ; Meghdari, A ; Sharif University of Technology
Cambridge University Press
2016
Abstract
In this paper, the problem of obtaining the optimal trajectory of a Dual-Arm Cam-Lock (DACL) robot is addressed. The DACL robot is a reconfigurable manipulator consisting of two cooperative arms, which may act separately. These may also be cam-locked in each other in some links and thus lose some degrees of freedom while gaining higher structural stiffness. This will also decrease their workspace volume. It is aimed to obtain the optimal configuration of the robot and the optimal joint trajectories to minimize the consumed energy for following a specific task space path. The Pontryagin's Minimum Principle is utilized with a shooting method to resolve kinematic redundancy. Numerical examples...
A review on the features, performance and potential applications of hydrogel-based wearable strain/pressure sensors
, Article Advances in Colloid and Interface Science ; Volume 298 , 2021 ; 00018686 (ISSN) ; Shojaei, A ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Over the past few years, development of wearable devices has gained increasing momentum. Notably, the demand for stretchable strain sensors has significantly increased due to many potential and emerging applications such as human motion monitoring, prosthetics, robotic systems, and touch panels. Recently, hydrogels have been developed to overcome the drawbacks of the elastomer-based wearable strain sensors, caused by insufficient biocompatibility, brittle mechanical properties, complicated fabrication process, as the hydrogels can provide a combination of various exciting properties such as intrinsic electrical conductivity, suitable mechanical properties, and biocompatibility. There are...
Introducing shell formation and a thermodynamics-inspired concept for swarm robotic systems
, Article Robotics and Autonomous Systems ; Volume 148 , 2022 ; 09218890 (ISSN) ; Alasty, A ; Sharif University of Technology
Elsevier B.V
2022
Abstract
In this article, a new formation for swarm robotic systems is introduced. This formation, which is made up of a portion of swarm members and encircles the whole swarm, is called the shell formation. In this regard, an effective algorithm for developing the shell formation in swarm robotic systems is established. The interaction mechanism among swarm agents is based on the method of artificial potential fields and the local rule of the nearest neighbor. Subsequently, inspired by the thermodynamic science and based on the introduced shell formation, the thermodynamic concept of pressure is generalized to swarm robotic systems. Finally, the efficacy of the introduced shell formation in solving...
Failure detection and isolation in robotic manipulators using joint torque sensors
, Article Robotica ; Volume 28, Issue 4 , 2010 , Pages 549-561 ; 02635747 (ISSN) ; Aghili, F ; Sharif University of Technology
2010
Abstract
Reliability of any model-based failure detection and isolation (FDI) method depends on the amount of uncertainty in a system model. Recently, it has been shown that the use of joint torque sensing results in a simplified manipulator model that excludes hardly identifiable link dynamics and other nonlinearities such as friction, backlash, and flexibilities. In this paper, we show that the application of the simplified model in a fault detection algorithm increases reliability of fault monitoring system against modeling uncertainty. The proposed FDI filter is based on a smooth velocity observer of degree 2n where n stands for the number of manipulator joints. No velocity measurement and...
Fast estimation of space-robots inertia parameters: A modular mathematical formulation
, Article Acta Astronautica ; Volume 127 , 2016 , Pages 283-295 ; 00945765 (ISSN) ; Malaek, S. M. B ; Sharif University of Technology
Elsevier Ltd
Abstract
This work aims to propose a new technique that considerably helps enhance time and precision needed to identify "Inertia Parameters (IPs)" of a typical Autonomous Space-Robot (ASR). Operations might include, capturing an unknown Target Space-Object (TSO), "active space-debris removal" or "automated in-orbit assemblies". In these operations generating precise successive commands are essential to the success of the mission. We show how a generalized, repeatable estimation-process could play an effective role to manage the operation. With the help of the well-known Force-Based approach, a new "modular formulation" has been developed to simultaneously identify IPs of an ASR while it captures a...