ABSTRACT
When a robotic system is pushed to its performance limits in terms of motion velocity and throughput, the problem of flexibility usually arises. Flexibility comes from physical deformation of the structure or compliance introduced by the feedback control system. For example, implementing a proportional and derivative (PD) controller is analogous to adding a spring and damper to the system. The controller “spring” can lead to problematic flexibility in the system. Deformation of the structure can occur in the links, cables, and joints. This can lead to problems with positioning accuracy, trajectory following, settling time, component wear, and stability and may also introduce nonlinear dynamics if the deflections are large.
