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stewart-platform
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Full order neural velocity and acceleration observer for a general 6-6 Stewart platform
, Article Conference Proceeding - 2004 IEEE International Conference on Networking, Sensing and Control, Taipei, 21 March 2004 through 23 March 2004 ; Volume 1 , 2004 , Pages 333-338 ; 0780381939 (ISBN) ; Shameli, E ; Sharif University of Technology
2004
Abstract
The aim of this work is to combine different innovative methods to solve the forward kinematics (FK) problem in a parallel manipulator called Stewart platform. It leads to the solution of a set of simultaneous non-linear equations and results in a series of non-unique multiple sets of solutions. Many efforts have been made to solve this challenging problem and usually results in having to find the solution of a 16th order polynomial by means of numerical methods such as Hooks-Jeeves, Steepest descent search and Newton-Raphson method (NR). Accuracy, speed and convergence of these methods are fully dependent to the initial guess vector that is fed to the numerical algorithm. In this paper, a...
Design and Analysis of a Cell Injection Manipulator Made of a Piezo-Driven Double-Deck Stewart Platform
, M.Sc. Thesis Sharif University of Technology ; Ahmadiyan, Mohammad Taghi (Supervisor)
Abstract
With respect to the introduction of bio-material into cells (transfection) , microinjection is a highly efficient technique amongst existing methodologies. In cell injection, a manipulator injects the needle into a cellwhich is hold by a pipet mechanism. The moving range for the needle in this operation is of centimeter order and the resolution for the needle tip should be less than the cell’s diameter. In this thesis a Stewart system is used as for the manipulator. Stewart systems are used in flight simulators systems for decades, as mechanisms which are capable of providing multi-axis movements. In high accuracy positioning and multi-axis applications Stewart systems are highly reliable....
Implementation and intelligent gain tuning feedback–based optimal torque control of a rotary parallel robot
, Article JVC/Journal of Vibration and Control ; Volume 28, Issue 19-20 , 2022 , Pages 2678-2695 ; 10775463 (ISSN) ; Ebrahimi Toulkani, N ; Sharif University of Technology
SAGE Publications Inc
2022
Abstract
Aiming at operating optimally minimizing error of tracking and designing control effort, this study presents a novel generalizable methodology of an optimal torque control for a 6-degree-of-freedom Stewart platform with rotary actuators. In the proposed approach, a linear quadratic integral regulator with the least sensitivity to controller parameter choices is designed, associated with an online artificial neural network gain tuning. The nonlinear system is implemented in ADAMS, and the controller is formulated in MATLAB to minimize the real-time tracking error robustly. To validate the controller performance, MATLAB and ADAMS are linked together and the performance of the controller on the...
The wide-open three-legged parallel robot for long-bone fracture reduction
, Article Journal of Mechanisms and Robotics ; Volume 9, Issue 1 , 2017 ; 19424302 (ISSN) ; Farahmand, F ; Gallardo Alvarado, J ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2017
Abstract
Robotic reduction of long bones is associated with the need for considerable force and high precision. To balance the accuracy, payload, and workspace, we have designed a new six degrees-offreedom three-legged wide-open robotic system for long-bone fracture reduction. Thanks to the low number of legs and their nonsymmetrical configuration, the mechanism enjoys a unique architecture with a frontally open half-plane. This facilitates positioning the leg inside the mechanism and provides a large workspace for surgical maneuvers, as shown and compared to the well-known Gough-Stewart platform. The experimental tests on a phantom reveal that the mechanism is well capable of applying the desired...
Controlling the Secondary Mirror of a Reflective Telescope Using a Controlled Stewart Platform
, M.Sc. Thesis Sharif University of Technology ; Salarieh, Hassan (Supervisor) ; Khayyat, Ali Akbar (Supervisor)
Abstract
Reflective telescopes are devices which commonly use two mirrors, to gather and reflect light rays. In these types of telescopes, the main responsibility of the secondary mirror is to lead the reflected light from primary to detection place. The purpose of this project is to adjust the secondary mirror’s position to reduce the optical errors. So, we are going to study the M2 unit of the telescope. The M2 unit consists of a Hexapod made with six linear actuators in the conventional 3-3 arrangement, and its function is the accurate positioning of the secondary mirror. The main performance required for the M2 unit is the active mirror position adjustment in 5 axes to compensate the existing...
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...
Optimal Design of an External Fixator for Knee Injuries & Deformities
, M.Sc. Thesis Sharif University of Technology ; Zohoor, Hassan (Supervisor)
Abstract
Since ancient time, healing patients suffering from bone deformities has been one of the most important challenges of physicians. In recent decades, by helping bio mechanic engineers external fixators has been used for this purpose. These fixators divided to parallel and series forms. One of the remarkable merit of parallel external fixators is their high maneuverability. These fixators usually have six degree of freedom, and follow the movement’s pattern of Stewart robots. In this project by studying different fixators which has been commercials, we present two conceptual models of these fixators which three and four legs are used for connecting the lower and upper plates, respectively. The...
Dynamics, Control, and Design of the Structure of a 6DOF Stewart Platform – Based Hydraulic Motion Simulator for Heavy Payloads
, M.Sc. Thesis Sharif University of Technology ; Durali, Mohammad (Supervisor)
Abstract
The robot considered in this project is to test parts and equipment installed in marine vessels under sea movements and waves. After a thorough assessment amongst common solutions to problems of this kind, a Stewart-Gough based manipulator has been chosen so that all the requirements could be satisfied. Therefore, according to the information obtained through relevant organisations, the purpose of this project is to work on dynamics, control, and design of the structure of a 6DOF Stewart platform – based hydraulic motion simulator for heavy payloads for samples weighing up to 2.5 tons which can handle linear accelerations up to 10 m/s2, rotary accelerations up to 150 º/s2 performing at a...
Analysis and Design of Controller and User Interface of a 6DOF Stewart Platform-Based Hydraulic Motion Simulator for Heavy Payloads
, M.Sc. Thesis Sharif University of Technology ; Durali, Mohammad (Supervisor)
Abstract
Motion simulators have been highly sought after by the growth of the aerospace industry. In the meantime, the Stewart mechanism, or the so-called Hexapads, is a robot that, in addition to being used in machining tools, is mainly used to simulate the flight. The Stewart-Gaph mechanism was created and introduced in 1954 and 1965, and since then dynamics and control have been widely addressed in the mechanical engineering literature. The robot is considering the project to test parts and equipment installed in marine vessels under sea movements and waves. Therefore, according to information obtained through relevant organs, the purpose of this project is to design and implement a hexapad...
Analysis and Design of Controller and user Interface of a 6DOF Stewart Platform – based Hydraulic Motion Simulator for Heavy Payloads
, M.Sc. Thesis Sharif University of Technology ; Durali, Mohammad (Supervisor)
Abstract
Motion simulators have been highly sought after by the growth of the aerospace industry. In the meantime, the Stewart mechanism, or the so-called Hexapads, is a robot that, in addition to being used in machining tools, is mainly used to simulate the flight. The robot is considering the project to test parts and equipment installed in marine vessels under sea movements and waves. Therefore, according to information obtained through real case studies, the purpose of this project is to design and implement a hexapad controller and user interface for samples weighing up to 2 tons which can handle linear accelerations up to 1 g, rotary accelerations up to 200 º / s2 performs at a frequency...