Industrial robots and automation technology have advanced rapidly in the last several decades. New
types of manipulators that uses parallel mechanisms are becoming more popular due to their high speed
and high stiffness. This thesis focuses on a sub-class of parallel manipulators that uses cables to replace
rigid links for further increase in speed. The design strategies in this study were expanded from research
works by Khajepour. Behzadipour, and Edmon Chan. This thesis presents analysis and development of a
new cable-based planar parallel manipulator that is based on a previous prototype built by Edmon Chan.
The new manipulator design added a new rotational DOF to the end-effector, and the number of
cables are doubled in order to increase the stiffness. New methods for kinematics and dynamics analysis
are formulated to make the procedure more systematic. A new mathematical formulation for stiffness
matrix of the end-effector is presented. The resultant stiffness matrix is equivalent to the stiffness matrix
formulated by Behzadipour. Additional stiffness analysis is conducted on valid range of stiffness
calculation and comparison of different cable configurations. A multi-objective optimization problem is
formulated in order to search for the best set of design parameters for the manipulator, and it is solved
with an exhaustive complete search method.
A physical prototype of the manipulator is modelled and manufactured with the help of partners from
Conestoga college. Experiments with the manipulator show that more powerful motors are needed to run
the robot at full speed. Motor torque measurements show that the dynamics analysis of the manipulator is
valid. Stiffness of the manipulator is measured by applying external force to the end-effector, and it is
shown to be strong. The manipulator is able to demonstrate a sort and pick-and-place operation at 60
cycles per minute while running at 70% of the maximum speed, with an acceleration of 2.8 g and velocity
of 4 m/s.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OWTU.10012/6605 |
| Date | January 2012 |
| Creators | Sun, Nan Nan |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation |
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