Modelling and control of flexible robot

The project deals with the modelling and control of flexible robot arms with special reference to be able to increase the payload/own weight ratio of manipulators. It is of vital importance to improve this ratio in the endeavour to improve the skills and the
efficiency of future robots.
The mechatronic approach in robotics is tested in a design case study of a pick and place 2 DOF SCARA robot as the restrictive constraint in the mechanical design that the links have to be rigid is relaxed. To maintain a good link tip position accuracy the relaxing of the constraint necessitate improved knowledge in the remaining involved disciplines in the integrated design in order to avoid that vibrations induced in the robot link have destructive effect on the tip positioning.
A brief introduction to the modelling of distributed parameter systems is subsequently given before the theory is applied in modelling a flexible robot arm. A number of link models are derived. The first two models presented describes in-plane transverse vibrations in a free rotating flexible robot link. (modal representation and finite element modelling). In some applications of manipulators they interact with the environment which affect the dynamics of a flexible link. This fact resulted in the derivation of three models of a flexible link used in tip force control. The extended knowledge of the behaviour of a working flexible robot link gained is used on the case study manipulator in a passive non-ad-hoc rigid robot design application and in an active flexible robot design application.
Out-of-plane link vibrations are treated as well in the thesis as they in most applications will be excitated too. In order to be able to damp the out-of-plane transverse vibrations a lightweight distributed piezoelectric actuator is introduced which acts as an active artificial stiffening in the particular direction.