Position control of multiple robots manipulating a flexible payload

Robotic manipulation of a flexible payload is a complex and challenging control problem. The paper shows in theory that under the widely used scheme of PD plus gravity compensation, the position/orientation of a general flexible payload manipulated by multiple robots approaches the desired one, and simultaneously the vibration of the payload at each contact is suppressed. The vibration suppression at each contact is helpful to suppress all vibrations of the flexible body. The "clamped-free" model is used to decompose the dynamics of the payload into two distinct dynamic subsystems. This allows us to treat these dynamic subsystems separately and prove that desired motion trajectories can be achieved with the proposed scheme. An example of experiment of manipulating a flexible sheet using two industrial CRS A460 robots is described finally.