Dynamic Feedback Control of XYnR Planar Robots with n Rotational Passive Joints

We consider the problem of trajectory planning and control for an XYnR̄ planar robot with the first two joints (rotational or prismatic) actuated and n rotational passive joints, moving both in the presence and the absence of gravity. Under the assumption that each passive link is attached at the center of percussion of the previous passive link, dynamics of the system can be expressed through the behavior of n special points of the plane. These points are called link-related acceleration points (LRAP) since their instantaneous acceleration is oriented as the axis of the related passive links. Moreover, LRAP dynamics present a backward recursive form which can be exploited to recursively design a dynamic feedback that completely linearizes the system equations. We use this approach to solve trajectory planning and tracking problems and report simulation results obtained for an RR2R̄ robot having the first two rotational joints actuated. © 2003 Wiley Periodicals, Inc. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •