Abstract:

This paper describes an experience carried out at Department of Mechanics of Politecnico di Milano in the course of "Functional Mechanical Design". The objective of this experience is to study the dynamics of a planar manipulator with flexible links.
The research interest in flexible manipulators, i.e. lightweight and large dimension robotic manipulators, has increased significantly in recent years. Major advantages of flexible manipulators include, but are not limited to; small mass, fast motion and large force to mass ratio, which are reflected in the reduced energy consumption, increased productivity and enhanced payload capacity. It should be noted that flexible manipulators have important applications in new and emerging fields, such as space exploration, manufacturing automation and construction.
In this study a 2 DoF flexible manipulator is considered. The manipulator consists of two flexible links: each one is connected to a slider at one side and to the other link on the other side through a revolute joint. Sliders are driven by brushless motors via screwball transmissions.
The first part of the work concerns the manipulator kinematic solving problems of direct kinematics (from the joint space to the workspace) and reverse (from the end effector coordinates to the ones of joints). At this stage, the manipulator is considered as rigid.
Subsequently the implementation of a multibody model of this system is carried out, with particular emphasis on the modelling of flexible elements.
The dynamic study is done trying to move the end effector of the manipulator along different trajectories, considering the positioning errors due to the structure limited stiffness.