Dynamic analysis, design and control of an industrial parallel robot
An investigation into the applicability of the bond-graph methodology, using the so-called Model Transformation Tools software, has been undertaken to model parallel robots. This software is a novel, non-commercial, program developed at the University of Glasgow, and in addition to the standard bond graph, it contains a powerful tool called the Hierarchical Bond Graph for dealing with very large-scale dynamical systems. It is the first time this tool has been applied for the modelling of parallel manipulators. A General Method for modelling parallel robots using the Hierarchical Bond-Graph concept has been developed. The method is based on related work on the modelling of closed chain robots using the Lagrange method. Introduction of a new design concept to be known as the Multi-cell Parallel Planar Manipulator. The methodology allows for an increase in the workspace of the manipulator by increasing the number of cells without affecting the number of DOF. It can also be shown to enhance the manoeuvrability of the system. Application of the multi-cell approach to a specific 2-DOF planar parallel manipulator and recognition of the need for a general model led to the development of a general dynamic model for the multi-cell manipulator using the Lagrange method. The reason for using the Lagrange formulation is that the necessary generalisation cannot be formalised using the Bond Graph technique due to the dependency of a bond graph on the specified structure of the system being modelled. Static balancing of the new general manipulator was addressed and a new method for balancing has been introduced. The method reduces the number of parameters to be adjusted to only one.