Friction control in terms of unnormalized quasi-velocities

This paper deals with problem of velocity control using a friction model which depends on kinematical and dynamical parameters of a manipulator. Both joint velocity controller and friction model are expressed in terms of unnormalized quasi-velocities (UQV). The controller is shown to be exponentially convergent. Some properties arising from investigation of the controller are considered here. The control strategy including the friction model was tested analytically on a 2 d.o.f. planar manipulator and in simulation on a 3 d.o.f. 3 - D, DDArm (direct drive arm) robot.