Development of a Parallel Spherical Robotic Mechanism as a Haptic Interaction Device for Telerobotic Applications

Abstract

This thesis presents a novel coaxial haptic interaction device for telerobotic applications. The device is based on a 3 Degree of Freedom (DoF) spherical parallel mechanism (SPM). In comparison to existing Spherical Parallel Mechanisms, a central hollow shaft is placed inside the manipulator and hence it becomes very stiff against translational forces. Additionally, to actuate the manipulator by motors, a new Coaxial Transmission Line (CTL) is introduced. The proposed design provides a full rotation around central hollow shaft axis, hence it achieved a larger workspace and better ergonomic compared to existing ones. Moreover, the developed interface can rotate fully while preserving constant orientation. To procure the optimum design with regard to kinematic, dynamic, and mechanical stiffness properties, a multi-objective optimization task by using a genetic algorithm is accomplished considering kinematic, dynamic, and stiffness performance indices. As a consequence of the optimization task, Pareto-Front solutions are obtained. The selection of a suitable solution is made by considering interchange between manipulability-condition number and natural frequency. To unveil the corresponding stiffness values, an experimental test setup is presented. The test results confirmed the validity, by means of the role of hollow shaft, of the developed haptic interface. The developed device can be readily integrated with another manipulator, for creating macro-micro manipulator structures, such as with Light Weight Robot (LRW) or Omega.3 from Force Dimensions.