Flexible robotic arm dynamics through deflection screw approach

The design and control of robotic systems capable of performing dynamic tasks, such as those involving stable impact, is of growing interest within the robotic community. If their structure is conceived as rigid, it results in massive and bulky systems, so that high forces are generated in the interaction with the external environment. At the opposite, if the robotic structure is designed as flexible, the interaction with the external environment produces lower forces thanks to their weight reduction and to the energy absorption guaranteed by the structural deformations. However, adding flexibility leads to unwanted vibrations which is a major drawback, that must be taken into account by the control algorithm to prevent resonance phenomena and to guarantee precise task performance. In this paper, the authors propose a structural model of a flexible robotic arm to be implemented in a model based control algorithm. The study is based on the screw theory approach which allows for an easy-to-manipulate concise symbolic representation for both kinematics and dynamics.