Parametric mechanical design and optimisation of the Canterbury Hand.
Thesis DisciplineMechanical Engineering
Degree GrantorUniversity of Canterbury
Degree NameMaster of Engineering
As part of worldwide research humanoid robots have been developed for household, industrial and exploratory applications. If such robots are to interact with people and human created environments they will require human-like hands. The objective of this thesis was the parametric design and optimisation of a dexterous, and anthropomorphic robotic end effector. Known as the ‘Canterbury Hand’ it has 11 degree of freedoms with four fingers and a thumb. The hand has applications for dexterous teleoperation and object manipulation in industrial, hazardous or uncertain environments such as orbital robotics. The human hand was analysed so that the Canterbury Hand could copy its motions, appearance and grasp types. An analysis of the current literature on experimental prosthetic and robotic hands was also carried out. A disadvantage of many of these hand designs was that they were remotely powered using large, heavy actuator packs. The advantage of the Canterbury Hand is that it has been designed to hold the motors, wires, and circuit boards entirely within itself; although a belt carried battery pack is required. The hand was modelled using a parametric 3D computer aided design (CAD) program. Two different configurations of the hand were created in the model. One configuration, as a dexterous robot hand, used Ø13mm 3 Watt DC motors, while the other used Ø10mm, 0.5 Watt DC motors (although this hand is still slightly too large for a general prosthesis). The parts within the hand were modelled to permit changes to the geometry. This was necessary for the optimisation process. The bearing geometry of the finger and thumb linkages, as well as the thumb rotation axis was optimised for anthropomorphic motion, appearance and increased force output. A design table within a spreadsheet was created to interact with the CAD models of the hand to quickly implement the optimised geometry. The work reported in this thesis has shown the possibilities for parametric design and optimisation of an anthropomorphic, dexterous robotic hand.