| The designs of two different parallel, wire-actuated 4 degrees of freedom robots have been investigated. The configuration of the first design was developed by Kossowski (2001), and the configuration of the second design was developed by the author with the help of Sahin (2003). Both designs utilize a central linkage to constrain the motion of the end effector to three translations and one pitch rotation.; The architecture of both designs is discussed in this thesis. After this, stability, strength, and stiffness are analyzed using finite element analysis and simulation programs. Finally, the detailed design work necessary for building a prototype is discussed.; The stability analysis involves ensuring that the wire-controlled robots are able to exert and withstand end effector forces in all directions without losing tension in the wires and causing the central linkage to move. The location of the wires is the most important factor in designing a stable robot, as is shown from the simulation results and finite element analysis.; The strength and stiffness analysis involves performing a static finite element analysis on both designs. Different positions of the robots are examined under various end effector loads to ensure that the stresses do not cause failure of the components, and the end effector displacements are reasonably low.; The detailed design work involves selecting materials, determining link and wire sizes, choosing actuators, and selecting joint sensors. It also involves using computer aided design programs to design and assemble the links and joints, and using a simulation program to ensure that there is no interference caused by the links, joints, or wires.; A working prototype of the second design has been built and could be used as a test bed for future research. |
