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impedance-controllers
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Total 45 records
A novel stable robust adaptive impedance control scheme for ankle prostheses
, Article 5th RSI International Conference on Robotics and Mechatronics, IcRoM 2017, 25 October 2017 through 27 October 2017 ; 2018 , Pages 63-68 ; 9781538657034 (ISBN) ; Sharifi, M ; Salarieh, H ; Alasty, A ; Sharif University of Technology
Abstract
A stable robust adaptive impedance control strategy is introduced here as a model-based low-level control scheme for active ankle prostheses. The effects of amputee-prosthesis and prosthesis-environment interactions are included in the controller design. An interesting feature of the proposed controller is that only shank and ankle angles and angular velocities, and ground reaction forces are required to implement the control law. In other words, no feedback from amputee-prosthesis interaction forces and moment, global or local positions, and accelerations of amputated place is required. Using a Lyapunov analysis, exponential convergence characteristics of the proposed controller are proven....
Stability and Performance Analysis of Human-Machine Interaction in Haptic Systems
, M.Sc. Thesis Sharif University of Technology ; Ahmadian, Mohammad Taghi (Supervisor) ; Vossoughi, Gholamreza (Supervisor)
Abstract
Transparency is a measure of performance in haptic devices. In order to improve transparency and reduce the difference between the impedance transmitted to the user and the target impedance it is necessary to compensate for the dynamics of the haptic device. Due to stability reasons improvement of transparency is limited. Passivity as a stability criterion has been used widely in design and analysis of haptic devices. Since passivity is a conservative criterion, it acts as an obstacle in improving transparency of the haptic interfaces. In this project instead of passivity, robust stability of the interaction is studied in the presence of parametric uncertainties due to variations in user...
Nonlinear model reference adaptive impedance control for human-robot interactions
, Article Control Engineering Practice ; Vol. 32 , 2014 , pp. 9-27 ; ISSN: 09670661 ; Behzadipour, S ; Vossoughi, G ; Sharif University of Technology
Abstract
Four nonlinear Model Reference Adaptive Impedance Controllers are introduced, tested, and compared for the control of the robot impedance with uncertainties in model parameters. The intended application area is human-robot interactions (HRI), particularly rehabilitation robots and haptic interfaces. All of the controllers make the closed-loop dynamics of the robot similar to the reference impedance model besides providing asymptotic tracking of the impedance model for the robot end-effector in Cartesian coordinates. The tracking and global stability are proved using Lyapunov stability theorem. Based on the simulations and experiments on a two-DOFs robot, the effectiveness of the proposed...
Development of a Control Method for Realizing Flexible Motion in Medical Robots
, M.Sc. Thesis Sharif University of Technology ; Vossoughi, Gholamreza (Supervisor) ; Behzadipour, Saeed (Supervisor)
Abstract
The main purpose of this project is to propose a control method for medical robots (such as rehabilitation and surgical robots), such that they can be moved conveniently by the users’s hand while he senses a controllable resistance. For that purpose, a Model Reference Adaptive Impedance Control method is developed for controlling the robot end-effector impedance in Cartesian coordinates. The proposed nonlinear controller and the desired impedance model are presented in Cartesian coordinates of the robot end-effector which is sensible for the human user. The adaptation law is derived and a corresponding Lyapunov stability is provided to prove the asymptotic tracking of the impedance model. By...
Dynamic Analysis and Control System Design for a Lower Extremity Exoskeleton
, M.Sc. Thesis Sharif University of Technology ; Salarieh, Hassan (Supervisor) ; Alasty, Aria (Supervisor)
Abstract
The present research has dealt with developing theoretic basis for technology of a modern and beneficial robot. There has been an old aspiration to attain some machine which can enclose body and move exactly in concert with it so as to maximize human might and endurance via powerful actuators. Exoskeleton robot is a recent successful invention regarding this aspiration, the lower-limbs type of which being sufficient for enhancing gait and load carrying capabilities.
Modeling the dynamics of this robot is very fundamental and was done thoroughly for the first time in this research. In the available articles, at most, simplified models are investigated. Mechanical structure was selected...
Modeling the dynamics of this robot is very fundamental and was done thoroughly for the first time in this research. In the available articles, at most, simplified models are investigated. Mechanical structure was selected...
Model reference adaptive impedance control in Cartesian coordinates for physical human-robot interaction
, Article Advanced Robotics ; Vol. 28, issue. 19 , October , 2014 , pp. 1277-1290 ; ISSN: 01691864 ; Behzadipour, S ; Vossough, G. R ; Sharif University of Technology
Abstract
In this paper, a nonlinear model reference adaptive impedance controller is proposed and tested. The controller provides asymptotic tracking of a reference impedance model for the robot end-effector in Cartesian coordinates applicable to rehabilitation robotics or any other human-robot interactions such as haptic systems. The controller uses the parameters of a desired stable reference model which is the target impedance for the robots end-effector. It also considers uncertainties in the model parameters of the robot. The asymptotic tracking is proven using Lyapunov stability theorem. Moreover, the adaptation law is proposed in joint space for reducing the complexity of its calculations;...
High-precision impedance control method for flexible base moving manipulators
, Article Advanced Robotics ; Volume 23, Issue 1-2 , 2009 , Pages 65-87 ; 01691864 (ISSN) ; Vossoughi, G. R ; Sharif University of Technology
2009
Abstract
The general problem of impedance control is addressed for a robotic manipulator with a moving flexible base. Impedance control imposes a relation between force and displacement at the contact point with the environment. The concept of impedance control of flexible base moving manipulators (FBMMs) is rather new and is being considered. The dynamic of the manipulator is decomposed into slow and fast dynamics using the singular perturbation method. A new sliding mode impedance control (SMIC) method using an element on the end-effector is proposed for high-precision impedance control of FBMMs. The SMIC method as a robust impedance control law is derived for the slow dynamics. The asymptotic...
Impedance control and gain tuning of flexible base moving manipulators using PSO method
, Article 2008 IEEE International Conference on Information and Automation, ICIA 2008, Zhangjiajie, Hunan, 20 June 2008 through 23 June 2008 ; 2008 , Pages 458-463 ; 9781424421848 (ISBN) ; Vossoughi, G. R ; Vajedi, M ; Brooshaki, M ; Sharif University of Technology
2008
Abstract
New gains tuning and impedance control method were addressed for flexible base moving manipulators. Slow and fast dynamics of robot are decoupled using singular perturbation method. Then, using sliding mode control method, an impedance control law was derived for the slow dynamics. Combined control law was proposed comprising the impedance control law and a feedback control law for the fast dynamics. As fist time, we proposed a new online particle swarm optimization algorithm for gain tuning of impedance control at the contact moments of end effector and unknown environments. This proposed Sliding Mode Impedance Controller and online PSO were simulated for a Flexible Base Moving Manipulator....
Nonlinear adaptive impedance control of virtual tool-tissue interaction for use in endoscopic sinus surgery simulation system
, Article 4th RSI International Conference on Robotics and Mechatronics, ICRoM 2016, 26 October 2016 through 28 October 2016 ; 2017 , Pages 66-71 ; 9781509032228 (ISBN) ; Sadeghnejad, S ; Vossoughi, G ; Moradi, H ; Farahmand, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
In this article, a nonlinear adaptive impedance control strategy is proposed to adjust the impedance of a one-degree of freedom Falcon robot to a pre-defined nonlinear impedance which is an approximate mathematical representation of the sino-nasal tissue. Further developments can be used for a training simulator system for the otolaryngology surgery training purposes. The stability of the proposed control strategy and convergence of tracking error are proved by using Lyapunov Stability Theorem. Two different scenarios are considered for simulation studies including a declining contact force and also an oscillatory contact force between the user hand and the haptic interface device....
Impedance control of flexible base mobile manipulator using singular perturbation method and sliding mode control law
, Article International Journal of Control, Automation and Systems ; Volume 6, Issue 5 , 2008 , Pages 677-688 ; 15986446 (ISSN) ; Vossoughi, G ; Sharif University of Technology
2008
Abstract
In this paper, the general problem of impedance control for a robotic manipulator with a moving flexible base is addressed. Impedance control imposes a relation between force and displacement at the contact point with the environment. The concept of impedance control of flexible base mobile manipulator is rather new and is being considered for first time using singular perturbation and new sliding mode control methods by authors. Initially slow and fast dynamics of robot are decoupled using singular perturbation method. Slow dynamics represents the dynamics of the manipulator with rigid base. Fast dynamics is the equivalent effect of the flexibility in the base. Then, using sliding mode...
Impedance control of flexible base mobile manipulators new method: SMIC for FBMM
, Article 13th IASTED International Conference on Robotics and Applications, RA 2007 and Proceedings of the IASTED International Conference on Telematics, Wurzburg, 29 August 2007 through 31 August 2007 ; 2007 , Pages 39-44 ; 9780889866850 (ISBN) ; Vossoughi, G ; Sharif University of Technology
2007
Abstract
In this paper, the general problem of impedance control for a robotic manipulator with a moving flexible base is addressed. Impedance control imposes a relation between force and displacement at the contact point with the environment. The concept of impedance control of flexible base mobile manipulator is rather new and is being considered for first time using singular perturbation and new sliding mode control methods by authors. Initially slow and fast dynamics of robot are decoupled using singular perturbation method. Slow dynamics represents the dynamics of the manipulator with rigid base. Fast dynamics is the equivalent effect of the flexibility in the base. Then, using sliding mode...
Impedance Control of Flexible Base Moving Manipulators
, Ph.D. Dissertation Sharif University of Technology ; Vossoughi, Gholamreza (Supervisor)
Abstract
In this paper, the general research of impedance control is addressed for a robotic manipulator with a moving flexible base. Impedance control imposes a relation between force and displacement at the contact point with the environment. The concept of impedance control of flexible base moving manipulators (FBMM) is rather new and is being considered. The dynamic of manipulator is decomposed into slow and fast dynamics using singular perturbation method. New sliding mode impedance control method (SMIC), using an element on the end effector is proposed for high precision impedance control of FBMM. The sliding mode impedance control method as a robust impedance control law is derived for the...
Dynamic Analysis of an Exoskeletal System to Assist a Paraplegic Motion
, Ph.D. Dissertation Sharif University of Technology ; Meghdari, Ali (Supervisor) ; Vossoughi, Gholam Reza (Co-Advisor)
Abstract
This research focuses on the dynamic analysis of an exoskeletal system to assist a paraplegic motion. Research in powered human exoskeletons began in the late 1960s, almost in parallel between the numbers of research groups for different applications. The main challenges for the recent work in exoskeletons were focused on the design and demonstration of an initial prototype. To this point, the reported advantages of the autonomous exoskeleton systems are largely anecdotal. Indeed, there is a marked lack of published quantitative performance results for exoskeleton devices that reportedly improve human locomotion. Considering this, there are many design challenges remained that may lead to...
Impedance Control of Stewart Platform with Optimal Gains
, M.Sc. Thesis Sharif University of Technology ; Ghafari, Ali (Supervisor) ; Ghaemi Osgouie, Kambeaz (Supervisor)
Abstract
The main scope of this research is developing an impedance control strategy for a six-degree-of-freedom parallel manipulator with the application in the milling process. One of the most common known parallel manipulators is the Stewart platform, which was proposed in 1965. [It evolved into a popular research topic of robotics in the 1980s.] Problems in various aspects of design, kinematics, dynamics, singularity and workspace analysis have been investigated in the literature. Derivation of control strategies taking advantage of the in-parallel structure or catering for the special problems arising out of that is another important field, whichhas been almost untouched till now.
The main...
The main...
Intelligent Force Control for Hydraulic Manipulator within the Impedance Control Framework
, M.Sc. Thesis Sharif University of Technology ; Khayyat, Amir Ali Akbar (Supervisor)
Abstract
The main concept of this thesis is to simulate, develop, and analyze the performance of force control method by applying to a Unimate MK-II hydraulic manipulator. In this investigation, simulation studies are based on the concept of impedance control technique. Position-based formulation of impedance control is employed. First in this research, a PID controller is employed and is shown to be capable of performing position control task precisely despite the fact that inertia, joint stiction, valve deadband and other nonlinearities are presented. Although trajectory tracking is performed well after several investigations, we have concluded that the impedance control cannot perform a desirable...
Impedance Force Control of a Robot Manipulator Using a Neuro-Fuzzy Controller
, M.Sc. Thesis Sharif University of Technology ; Khayyat, Amir Ali Akbar (Supervisor)
Abstract
The present study discusses the problem of enabling a PUMA 560 electrical robot manipulator to interact with the environment using impedance control concept. The impedance control strategy maintains a pre-specified desired second order dynamic relation between the end-effector position and force and enables a stable transmission between unconstrained and constrained motion. In this study Position-Based Impedance Control (PBIC) is used which is more suitable for industrial manipulators. PBIC requires a position controller with high accuracy. Therefore, a nonlinear PID controller is used in the position loop which is capable of both tracking and regulating of the input signals and shows better...
Robust stable control of haptic devices based on transparency maximization
, Article ASME 2010 International Mechanical Engineering Congress and Exposition, IMECE 2010, Vancouver, BC, 12 November 2010 through 18 November 2010 ; Volume 8, Issue PARTS A AND B , 2010 , Pages 773-780 ; 9780791844458 (ISBN) ; Ahmadian, M ; Vossoughi, G ; Sharif University of Technology
2010
Abstract
Performance of a haptic device is evaluated based on the concept of transparency. Stability of a haptic device prevalently has been evaluated based on the passivity criterion. Due to conservativeness of passivity, it appears as an obstacle to improve transparency. In this paper, passivity is suggested to be replaced by the complementary stability criterion which accounts for the robust stability of the interaction in the presence of uncertain user hand dynamics. In this respect, an algorithm is proposed which guarantees transparency of the haptic device in a stable manner. Assuming that the dynamics of the device is known, a certain compensatory structure is assigned. This special structure...
Design and control of an assistive exoskeleton with passive toe joint
, Article International Journal of Mechatronics and Automation ; Volume 6, Issue 2-3 , 2018 , Pages 83-93 ; 20451059 (ISSN) ; Shariat, A ; Khezrian, R ; Zibafar, A ; Rashidi, A. R ; Rostami, H ; Vossoughi, G. R ; Selk Ghafari, A ; Sharif University of Technology
Inderscience Enterprises Ltd
2018
Abstract
Several exoskeletons with various configurations and degrees-of-freedoms (DOFs) have been introduced in the literature, but not many have addressed the optimal selection of the mechanism's DOFs. In the proposed system a semi-passive toe joint is introduced to achieve several advantages. The performance of the proposed novel passive toe joint is evaluated experimentally. In addition, the semi-passive abduction/adduction DOFs in the hip joint and eversion/inversion DOFs in ankle joint is proposed to facilitate turning while providing more comfort during normal walking. The effect of passive DoFs existence on the user comfortability is studied with the aid of three kinematic indices. In the...
Model reference adaptive impedance control of rehabilitation robots in operational space
, Article Proceedings of the IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics, 24 June 2012 through 27 June 2012 ; June , 2012 , Pages 1698-1703 ; 21551774 (ISSN) ; 9781457711992 (ISBN) ; Behzadipour, S ; Vossoughi, G. R ; Sharif University of Technology
2012
Abstract
A new nonlinear model reference adaptive impedance controller is presented for the control of robot manipulators with uncertainties in model parameters such as friction coefficients. This method provides asymptotic tracking of a reference impedance model for the robot end-effector in operational space which is more sensible for the patient compared to the joint space impedance used in previous works. The model uncertainties such as friction coefficients are compensated using an adaptation law. The asymptotic tracking of the reference impedance model is shown using a Lyapunov function. The tracking performance and friction compensation are also demonstrated through simulation on a...
Mechanical design, fabrication, kinematics and dynamics modeling, multiple impedance control of a wrist rehabilitation robot
, Article International Conference on Robotics and Mechatronics, ICROM 2015, 7 October 2015 through 9 October 2015 ; 2015 , Pages 290-295 ; 9781467372343 (ISBN) ; Nasr, A ; Moosavian, S. A. A ; Zohoor, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Rehabilitation is the best approach for patients who suffer physical disability of their upper-limbs. Maintaining the intensity of exercise during treatment is the main factor that makes the robots suitable for rehabilitation since robots do not get tired and do the exercises with constant intensity under supervision of the doctor. Two main categories of rehabilitation robots are End-Effector based robots and wearable robots. According to the fact that most problems occur in need of rehabilitation for hand wrist area, in this paper a wearable rehabilitation robot has been developed for the wrist. Nowadays, wearable robots attract more attention than the other group. Wearable robots are...