A robotic surgical system has a robot arm holding an instrument for
performing a surgical procedure, and a control system for controlling
movement of the arm and its instrument according to user manipulation of
a master manipulator. The control system includes a filter in its forward
path to attenuate master input commands that may cause instrument tip
vibrations, and an inverse filter in a feedback path to the master
manipulator configured so as to compensate for delay introduced by the
forward path filter. To enhance control, master command and slave joint
observers are also inserted in the control system to estimate slave joint
position, velocity and acceleration commands using received slave joint
position commands and torque feedbacks, and estimate actual slave joint
positions, velocities and accelerations using sensed slave joint
positions and commanded slave joint motor torques.