Search for: desired-trajectories
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    Modeling and velocity control of a-shape microrobot with adaptive neural network controller

    , Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Vol. 4A, issue , 2014 Nojoumian, M. A ; Shirazi, M. J ; Vossoughi, G. R ; Salarieh, H ; Sharif University of Technology
    Design and control of micro robots have been one of the interesting fields in robotics in recent years. One class of these micro robots is the legged robots. Various designs of legged robots have been proposed in the literature. All designs rely on friction for locomotion. In this paper dynamic model of a planar two-legged micro robot is presented using Luger friction model, and an adaptive neural controller used to control the robot to improve robustness and velocity of the robot. As mentioned earlier, friction plays an important role in locomotion of the legged robots. However, especially in legged micro robots, it is difficult to model the frictional force correctly since environmental... 

    Robust decentralized control of consensus-based formations of leader-follower networks with uncertain directed topologies on bounded velocity trajectories unde ned for followers via backstepping method

    , Article Scientia Iranica ; Volume 23, Issue 3 , 2016 , Pages 1064-1072 ; 10263098 (ISSN) Sayyaadi, H ; Soltani, A ; Sharif University of Technology
    Sharif University of Technology  2016
    In this paper, decentralized control of formation of a special category of leaderfollower networks on bounded velocity trajectories is addressed. The network of the agents in this study is supposed to have a directed graph with a spanning tree rooted at the leader agent. Moreover, follower agents do not receive online or have offine velocity of the desired trajectory, such as in tracking problem of trajectories which are not predefined or when the total bandwidth is narrow. Furthermore, the leader does not receive any information from any agent and its control is fully centralized. In the present study, formation problem is considered a consensus problem. The controller is designed for... 

    Vehicle trajectory challenge in predictive active steering rollover prevention

    , Article International Journal of Automotive Technology ; Volume 18, Issue 3 , 2017 , Pages 511-521 ; 12299138 (ISSN) Ghazali, M ; Durali, M ; Salarieh, H ; Sharif University of Technology
    High center of mass vehicles are likely to rollover in extreme maneuvers. Available works present control strategies to prevent rollover. In these works, however, other important parameters such as path trajectory tracking are not a main concern. In this paper conflicts between rollover prevention and trajectory tracking is investigated. Model predictive control (MPC) is adopted to predict and avoid rollover while tracking desired trajectory. For this regard a model based future error estimation is introduced. The control framework predicts both rollover and trajectory error simultaneously. It avoids rollover while tries to track the trajectory. Simulation results for two controllers with... 

    Dynamic modelling and control of a sphere-based micro robot with adjustable arm

    , Article MARSS 2018 - International Conference on Manipulation, Automation and Robotics at Small Scales, 4 July 2018 through 8 July 2018 ; 2018 ; 9781538648414 (ISBN) Esfandbod, A ; Nejat Pishkenari, H ; Meghdari, A ; Sharif University of Technology
    In this article, we propose a three-dimensional model of a low-Reynolds-number swimmer that consists of three small spheres connected to a larger sphere via three perpendicular adjustable rods which enable the micro robot to swim along arbitrary trajectories. Then we focus on dynamic modelling of the swimmer and propose a control method to control the position of the micro swimmer in a low Reynolds number flow. The control aim intended in this article is that the middle sphere to follow a desired trajectory and respective simulation results from control indicates successful accomplishment in application. © 2018 IEEE  

    A new fast finite time fractional order adaptive sliding-mode control for a quadrotor

    , Article 7th International Conference on Control, Instrumentation and Automation, ICCIA 2021, 23 February 2021 through 24 February 2021 ; 2021 ; 9780738124056 (ISBN) Naderi Soorki, M ; Vedadi Moghaddam, T ; Emamifard, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Fast finite time adaptive sliding mode control of a quadrotor in the presence of uncertainties and unbounded external disturbances is dealt in this paper. To this end, a fractional order sliding surface is first defined and then, an adaptive sliding mode controller is designed to guarantee finite time stability with fast convergence of quadrotor states to the desired trajectory. In this controller, it is assumed that the upper bound of the model uncertainties and external disturbances is a nonlinear function with unknown coefficients. These coefficients are estimated via stable adaptive laws. Finite time stability of the closed-loop system is analyzed using Lyapunov theorem. Simulation...