Robot singularity rate control with phantom d.o.f. strategy

Singularity is an inherent problem and an important obstacle to be overcome in robotic kinematics. When it is near a singular configuration, a robot loses one or more degrees of freedom (d.o.f.), and joint velocities approach infinitely leading to control instability. A strategy for stabilizing robot rate control near or at a singularity (degenerate) configuration using phantom d.o.f. is proposed. The phantom d.o.f. is considered as part of a robot kinematic velocity model and is activated only when the joint velocity exceeds its limit or at singularity configurations. A numerical illustration of singularity control of a 5-d.o.f. robot is discussed.<>