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robot-controls
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Control of the cedra brachiation robot using combination of controlled lagrangians method and particle swarm optimization algorithm
, Article Iranian Journal of Science and Technology - Transactions of Mechanical Engineering ; Volume 44, Issue 1 , 2020 , Pages 11-21 ; Vossoughi, G ; Azadi Yazdi, E ; Sharif University of Technology
Springer
2020
Abstract
This paper studies the control of a brachiating robot imitating the locomotion of a long armed ape. The robot has two revolute joints, but only one of them is actuated. In this paper, after deriving dynamic model of the robot, the Controlled Lagrangians (CL) method is used to design a controller for point to point locomotion. The CL method involves satisfying a number of equations called matching conditions. The matching conditions are derived using the extended λ-method in the form of a set of partial differential equations (PDEs). Solving the PDEs, a class of controllers is found that satisfies the matching conditions. The fittest controller in the class of controllers is then chosen by...
A computationally efficient algorithm to find time-optimal trajectory of redundantly actuated robots moving on a specified path
, Article Robotica ; 2018 ; 02635747 (ISSN) ; Sadigh, M. J ; Fazeli, M ; Sharif University of Technology
Cambridge University Press
2018
Abstract
time-optimal problem for redundantly actuated robots moving on a specified path is a challenging problem. Although the problem is well explored and there are proposed solutions based on phase plane analysis, there are still several unresolved issues regarding calculation of solution curves. In this paper, we explore the characteristics of the maximum velocity curve and propose an efficient algorithm to establish the solution curve. Then we propose a straightforward method to calculate the maximum or minimum possible acceleration on the path based on the pattern of saturated actuators, which substantially reduces the computational cost. Two numerical examples are provided to illustrate the...
Robot control using an inexpensive P300 based BCI
, Article 26th National and 4th International Iranian Conference on Biomedical Engineering, ICBME 2019, 27 November 2019 through 28 November 2019 ; 2019 , Pages 204-207 ; 9781728156637 (ISBN) ; Shamsollahi, M. B ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Brain Computer Interfaces (BCI) are an important concept of biomedical engineering because of their ability to improve life conditions for people with different disabilities. Lots of studies have worked on important characteristics of BCI systems, such as speed and accuracy, whereas price is an important aspect too. Thus, a low cost BCI system with high accuracy clearly can help more people. Our purpose in this study is to design a P300 based BCI system using a low-priced EEG headset which has an acceptable accuracy. Our final design got a mean real-time accuracy of 93.3% which is comparable to systems with much more expensive hardware. © 2019 IEEE
Optimal control of multiple-arm robotic systems using gradient method
, Article 2004 IEEE Conference on Robotics, Automation and Mechatronics, 1 December 2004 through 3 December 2004 ; 2004 , Pages 312-317 ; 0780386469 (ISBN); 9780780386464 (ISBN) ; Sadati, N ; Sharif University of Technology
2004
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, coordination of multiple-arm robotic systems in order to carry a rigid object is considered and the state space equations for the overall system are developed. Coordination of the robot arms is done through minimizing a related cost function based on the gradient method. This method is simple and easy to be used
A non-user-based BCI application for robot control
, Article 2018 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2018, 3 December 2018 through 6 December 2018 ; 2019 , Pages 36-41 ; 9781538624715 (ISBN) ; Shamsollahi, M. B ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Steady State Visual Evoked Potential (SSVEP) based Brain Computer Interfaces (BCI) can be great assistance for people suffering from physical disabilities due to their high accuracy, high speed, an acceptable number of possible targets, etc. Many researchers have managed to design such systems. Most of these BCIs utilize methods for frequency detection which cause the system to need a training phase for each new user, making the system a user-based one. That is why our goal was to design a BCI that not only has accuracy and speed comparable to similar systems, but also does not need any training phase and thus can be used by new users right away. Our final design got a mean accuracy of...
A new hierarchical approach for optimal control of robot manipulators
, Article 2004 IEEE Conference on Robotics, Automation and Mechatronics, 1 December 2004 through 3 December 2004 ; 2004 , Pages 306-311 ; 0780386469 (ISBN); 9780780386464 (ISBN) ; Babazadeh, A ; Sharif University of Technology
2004
Abstract
In this paper, a new approach for optimal control of robot manipulators is presented. For this purpose, the system is considered as a two-level large-scale system where a gradient based coordination strategy is used to coordinate the overall system. This is achieved within a decomposition-coordination framework, where the robot manipulator is first decomposed into several sub-systems in such a way that each sub-system consists of several consecutive links and joints. With the aim of optimization, the control problem is first decomposed into m sub-problems, at the first level, where each sub-problem is solved using a gradient optimization method. Then, by using a new methodology which is...
Robot Control By Port-Hamiltonian Approach
, M.Sc. Thesis Sharif University of Technology ; Namvar, Mehrzad (Supervisor)
Abstract
This thesis is devoted to deriving a port Hamiltonian control approach for different scenarios of brachiation movement by a two-link underactuated planar robot called brachiation robot. The port Hamiltonian modeling and control of this type of robot is introduced for the first time and shows promising results in the analysis and simulation as will be showed here. Animals have long inspired roboticists. Their dexterity, versatility, flexibility of motion and great variety of behaviors has made them benchmarks for robot performance. Recently things have begun to change and robots are now capable, to a limited degree, of mimicking the behavior of animals. This paper studies a type of...
Control of Exoskeletal System in Coordination with Upper Extremity System
, M.Sc. Thesis Sharif University of Technology ; Jahed, Mehran (Supervisor)
Abstract
With technological advances in fabrication and control of prosthesis and assistive devices the importance of such systems has increased drastically. On the other hand the appropriate coupling of these devices, especially the exoskeletal systems with the upper or lower extremities is of immense importance as it is an integral part of the control system. In particular, the control strategy and its ability to adapt the exoskeletal system with the existing and physiological functionality of the user, is an integral part of the system requirement. In the controller implementation, a number of methods are proposed including using the excitation signal, similar to the existing neuromuscular system....
Geometric control of the brachiation robot using controlled Lagrangians method
, Article 2014 2nd RSI/ISM International Conference on Robotics and Mechatronics, ICRoM 2014 ; 17 December , 2014 , Pages 706-710 ; Vossoughi, G ; Yazdi, E. A ; Sharif University of Technology
Abstract
This paper studies a brachiation robot that is a long armed locomotion similar to apes. The robot has 2 revolute joints but only one of them is actuated. In this paper, after deriving dynamic model of the robot the Controlled Lagrangian (CL) method is used for stabilization. The matching conditions satisfied for the controller are derived and the extended λ-method is used to solve PDE's involved in the method of controlled lagrangian. Satisfactory controller's gains are chosen by PSO algorithm. Finally, feasibility of the developed controller is investigated by numerical simulations
Decentralized control of reconfigurable robots using joint-torque sensing
, Article International Conference on Robotics and Mechatronics, ICROM 2015, 7 October 2015 through 9 October 2015 ; 2015 , Pages 581-585 ; 9781467372343 (ISBN) ; Sharif University of Technology
Abstract
In this paper, a decentralized controller for trajectory tracking of modular and reconfigurable robot manipulators is developed. The proposed control scheme uses joint-torque sensory feedback; also sliding mode control is employed to make both position and velocity tracking errors of robot manipulators globally converging to zero. Proposed scheme also guarantees that all signals in closed-loop systems will be bounded. In contrast to some of prior works in this scheme, each controller uses a smooth law to achieve its purposes. In this method, each controller uses only local information for producing control law hence separated controller can be used to control each module of manipulator and...
Design, Fabrication and Hovering Control of a Quadrotor Aerial Vehicle
, M.Sc. Thesis Sharif University of Technology ; Meghdari, Ali (Supervisor) ; Nejat Pishkenari, Hossein (Supervisor)
Abstract
One of the most significant aerial vehicles which has been subject of study of so many engineers and students is quadrotor or quadcopter, which is a cross sectional configuration of motors and propellers. This aerial robot is controlled through slight differences between the angular velocities of the four motors, and robot dynamics is completely nonlinear, thus sophisticated control algorithms are needed. The aim of this project consists of design, fabrication and control of a quadrotor capable of stable hovering. First, some preliminary decisions about general charachteristics of the robot were made. According to these decisions, other mechanical parts were designed and fabricated. Then,...
Control of an Active Exoskeleton Robot to Assist Human Elbow and Wrist Motion
, M.Sc. Thesis Sharif University of Technology ; Zohoor, Hassan (Supervisor) ; Behzadipour, Saeed (Co-Advisor)
Abstract
Most elderly and physically disabled people suffer from lack of functionality and dexterity in their elbow or wrist. These disabilities are due to the damages mostly caused by sport surgery, spinal surgery, or stroke. Therefore, design of an assistive exoskeleton robot for upper limb movements seems necessary. The purpose of this study is to design, fabricate and deliver a control algorithm for an assistive wearable robot. The robot has two degrees of freedom in order to help the flexion/extension of elbow and wrist. Furthermore, various kinds of control systems incorporated in rehabilitation robots are investigated and their advantages and drawbacks are compared. Then, some conventional...
Design and Implementation of a Search and Rescue System on a Quadrotor
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohammad (Supervisor)
Abstract
In this work, we try to develop a method for searching for an object which is known to us and also returning it back where the search was begun, through shortest possible path. The surrounding environment was assumed unknown and only a stereo camera and an IMU exist to work with. The proposed method was developed in Linux using GPU and with C++ language and also achieved 58 fps. Parallel programming was utilized in different parts of the algorithm and obstacle avoidance is guarranteed. The surrounding environment and obstacles are assumed changing over the time
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...
Design and Fabrication of An Electromagnetic Actuation System for Generation of Desired Magnetic Field and Control of Magnetic Particles
, M.Sc. Thesis Sharif University of Technology ; Nejat Pishkenari, Hossein (Supervisor)
Abstract
Being harmless to living tissues makes magnetic robots very promising for medical applications. Furthermore, since these robots are driven by external magnetic fields, no actuators are needed to be placed on the robots, enabling them to come in very small dimensions if necessary. Motion control of small magnetic particles paves the way for future applications, such as deliberate drug-delivery, sampling, and lowinvasive surgeries.The goal of this research is to design and construct a platform for generating desired magnetic fields in order to control the motion of magnetic robots in threedimensional space. In order to do so, a system of eight electromagnetic coils with iron cores was built....
Learning Interactive Skills of NAO Robot through Imitation Learning from Observation
, M.Sc. Thesis Sharif University of Technology ; Meghdari, Ali (Supervisor) ; Taheri, Alireza (Supervisor)
Abstract
Using learning from demonstration approaches is one of the ways to teach a robot how to perform different skills. In classic methods of learning from demonstration, the subject should wear some sensors and devices which is and expensive way. But, with the progresses that have been made in the context of computer vision, it is possible now to achieve to the same results with less cost. Learning from observation is the approach that would be used in this project to do that. By using this method, when robot watches a video, it tries to understand the behavior of the subject and behave in the same way.The purpose of the project is that the robot learns some social (interactive) skills through...
Identification and Control of Robot Manipulators using Cell Phone Sensors
, M.Sc. Thesis Sharif University of Technology ; Namvar, Mehrzad (Supervisor)
Abstract
The goal of controlling robot manipulators is to perform the mission intended for its end effector. Model-based control is a solution that can achieve the control goal with high speed and accuracy in the presence or absence of environmental obstacles by using the knowledge of the robot model. In this thesis, the Armtin 5 robot model parameters were identified in two steps. In the first step, the gravity and friction parameters and in the second step, the dynamic parameters were estimated. In the estimation of gravity and friction parameters, the non-linear behavior of friction causes the estimated parameters to be accompanied by a large amount of error. Estimation of the parameters was...
New robust control method applied to the locomotion of a 5-link biped robot
, Article Robotica ; 2019 ; 02635747 (ISSN) ; Salarieh, H ; Sharif University of Technology
Cambridge University Press
2019
Abstract
This paper proposes a new design of robust control combining feedback linearization, backstepping, and sliding mode control called FLBS applied to the locomotion of five-link biped robot. Due to the underactuated robot's model, the system has a hybrid nature, while the FLBS control can provide a stabilized walking movement even with the existence of large disturbances and uncertainties by implementing smooth chatter-free signals. Stability of the method is proven using the Lyapunov theorem based on the hybrid zero dynamics and Poincaré map. The simulations show the controller performance such as robustness and chatter-free response in the presence of uncertainty and disturbance. © 2020...
Position control of a wheel-based miniature magnetic robot using neuro-fuzzy network
, Article Robotica ; Volume 40, Issue 11 , 2022 , Pages 3895-3910 ; 02635747 (ISSN) ; Pishkenari, H. N ; Zohoor, H ; Sharif University of Technology
Cambridge University Press
2022
Abstract
Untethered small-scale robots can accomplish tasks which are not feasible by conventional macro robots. In the current research, we have designed and fabricated a miniature magnetic robot actuated by an external magnetic field. The proposed robot has two coaxial wheels and one magnetic dipole which is capable of rolling and moving on the surface by variation in the direction of magnetic field. To generate the desired magnetic field, a Helmholtz electromagnetic coil is manufactured. To steer the robot to the desired position, at first the robot dynamics is investigated, and subsequently a controller based on a neuro-fuzzy network has been designed. Finally, the proposed controller is...
Cooperative Control of a Quadrotor and a Mobile Robot
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Gholamreza (Supervisor)
Abstract
In this project, the final goal is to create a team consisting of a UGV and a quadrotor capable of relative tracking and coordinated landing, with focus on quadrotor control. What we mean by cooperative control in this project is control of quadrotor for the purpose of cooperation with a UGV; This should not be mistaken with another sense of cooperative control in which the control algorithms are developed for both of the robots or are based on the interactive dynamics of the robots.In order to accomplish this goal, an experimental testbed consisting of a quadrotor and a UGV capable of communication and data exchange was developed as a first step. The quadrotor was constructed using...