Design, characterization and experimental testing of two novel reconfigurable joints

Résumé

This Thesis focuses on the conception and design of joints to be used in reconfigurable parallel manipulators. A set of different joint designs was proposed and subjected to characteristics analysis in order to select the ones that provide better qualities. From the comparison among the various designs, it has been shown that two of them present such potential benefits as big workspace area, high load capacity and accuracy, small inertia forces, simplicity of manufacturing, and small dimensions. Therefore, these two joints were selected for further study, performing an in-depth analysis of their application as reconfigurable joints. Their kinematics and structural analysis have been carried out.The joints¿ reconfiguration ability and performance were tested by application of the joint prototypes in haptic device that controlled a 2-RFR planar ultraflexible parallel manipulator. The haptic device was equipped with a force feedback system that was intended to help indicating the singular areas of the workspace in which the control of the manipulator can be lost. Both joint designs were tested by a group of operators that was asked to perform several testing tasks. The results of the test demonstrate that the proposed joint designs are suitable for implementing them as haptic device and presenting the ability of joint reconfiguration. They provide reliable operation and control simplicity. After thorough analysis of the experimental results, the most beneficial joint design and the most appropriate control mode for it were determined. After adapting this design to conventional manufacturing technologies, the joint could be tested in a commercially available manipulator.