Full text
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| Author(s): |
Fernanda Thaís Colombo
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Carlos. |
| Institution: | Universidade de São Paulo (USP). Escola de Engenharia de São Carlos (EESC/SBD) |
| Defense date: | 2018-05-24 |
| Examining board members: |
Maíra Martins da Silva;
Adilson Gonzaga;
Tatiana de Figueiredo Pereira Alves Taveira Pazelli
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| Advisor: | Maíra Martins da Silva |
| Abstract | |
The duality between the main characteristics of serial and parallel manipulators hints that a control method that works well for one of them may not be suited for the other type. Although serial manipulators are described by the angular position of their joints, parallel manipulators are defined by the position of their end-effector in Cartesian space. The main subject of this document is a numeric and experimental study of control approaches for parallel manipulators in Cartesian space, which constitutes an area of control that does not have many experimental results, due to the difficulty of the techniques required. In order to control the movement of the manipulator in the Cartesian space, the position of the end-effector is needed. This measurement can be obtained through visual servoing, which allows visual information to be acquired from a camera that observes the movement of the system. Furthermore, the control strategy used in this project is based on the computed torque in Cartesian space, taking into consideration the manipulator\'s dynamics. The experimental analysis of this control method was done in a prototype of the planar parallel manipulator called 3RRR, with 3 kinematic chains and 3 actuated joints, which is available in the Laboratório de Dinâmica at EESC/USP. Due to the properties of the visual servoing method used, such as acquisition rate and image resolution, a different control strategy called High-Authority Low-Authority was used, capable of joining two control methods that have different actuation frequencies. The High-Authority half of this system, based on computed torque in the Cartesian space, generates a control signal with higher precision, while the Low-Authority is responsible for updating the control signal at a higher frequency, based on the angular position of the joints. Therefore, a good performance control strategy based on High-Authority Low-Authority was developed for tasks involving high accelerations in parallel manipulators (AU) | |
| FAPESP's process: | 15/25936-4 - Cartesian Space Computed Torque Control for Planar Parallel Kinematic Machines using Visual Servoing |
| Grantee: | Fernanda Thaís Colombo |
| Support Opportunities: | Scholarships in Brazil - Master |