Dynamical modelling and control of a flexible serial robot

The main goals of the work are the renewal of the mechanical design of the serial elastic robot ELBROB of the INSTITUTE OF ROBOTICS (Linz) and the building of two models of the robot: one that considers the members of the robot as rigid and another one that contemplate the elasticity of the bodies. The mechanical design consists in the choice and adaptation of a new gearmotor on the first axe of the robot due to malfunctions in the previous transmission and in a new design for the angular plates supporting the gearmotor of the third axe. A simple PD control is then implemented on both models. Both the elastic and rigid models of the robot are obtained with the energetic method of the Projection Equation in subsystem representation (the deformation of elastic members is modelled thanks to Ritz method). The subsystems are then combined in order to form a complete system in minimal form. On the real robot the control logic is developed using the Stateflow toolbox in MatLab/SimuLink, that covers safety monitoring and all the tasks performed by the robot. Thanks to the control logic developed in MatLab/SimuLink R it is possible to use the software ControlDesk from dSPACE to design an interface that allows to initialize the robot, make the robot perform desired trajectories and to monitor input and output signals in real time. Once the control logic is written it is possible to design trajectories in Cartesian space. Finally, the signals from the strain gauges are compared to the ones predicted with the rigid body models that was developed, in order to validate it.