Systems and methods for cancellation of joint motion using the null-space

A tele-surgical method comprising:

• providing a manipulator arm configured to support a distal tool with a distal end effector and an elongate intermediate portion disposed along an insertion axis and supporting the end effector for manipulating the end effector through a minimally invasive aperture, wherein the manipulator arm has a proximal portion coupled to a base, and a plurality of joints, the plurality of joints having sufficient degrees of freedom to allow a range of joint states for a given end effector position, wherein at least some of the joints comprise remote center joints mechanically constrained to pivotal movement about a remote center along the insertion axis and adjacent the minimally invasive aperture;
• receiving a manipulation command to move the end effector with a desired end effector movement;
• calculating an end effector displacing movement of the joints to effect the desired end effector movement, wherein calculating the end effector displacing movement of the joints comprises calculating joint velocities within a null-perpendicular-space of a Jacobian of the joints;
• calculating a cancellation movement of the plurality of joints within a null-space of the Jacobian to cancel the calculated velocities of a designated non-moving subset of the joints, wherein calculating the movement comprises calculating joint velocities, the null-space being orthogonal to the null-perpendicular space;
• and
• driving the joints according to the calculated movements so as to effect the desired end effector movement.

A tele-surgical system comprising:

• a manipulator arm configured for robotically moving a distal end effector relative to a proximal base, the manipulator arm having a plurality of joints between the distal portion and a proximal portion coupled to the base, the joints providing sufficient degrees of freedom to allow a range of joint states for a given state of the distal portion;
• an input for receiving a manipulation command to move the end effector with a desired end effector movement;
• and
• a processor coupling the input device to the manipulator arm, the processor configured to:
• calculate an end effector displacing movement of the joints in response to the manipulation command by calculating joint velocities within a null-perpendicular-space of a Jacobian of the joints, the calculated joint velocities including a velocity of a designated non-moving joint included in the plurality of joints;
• calculate a cancellation movement of the joints within a null-space, the calculated cancellation movement including a velocity of the non-moving joint configured to cancel the calculated velocity of the designated non-moving joint;
• and
• transmit a command to the manipulator arm in response to the end effector displacing movement and the cancellation movement so as to drive the manipulator arm per the manipulation command and inhibit movement of the non-moving joint.

A tele-surgical system comprising:

• a surgical instrument having a proximal end, a distal end effector suitable for insertion into a patient, and an intermediate portion having an insertion axis therebetween;
• a manipulator arm configured to support the proximal end of the instrument so as to pivot the instrument from outside the patient, wherein the manipulator arm and instrument include a plurality of driven joints, the joints providing sufficient degrees of freedom to allow a range of joint states for a given state of the end effector, wherein the joints of the manipulator comprise remote center joints configured to mechanically constrain movement of the distal portion to pivot about a remote center pivot point along the insertion axis and adjacent a minimally invasive aperture;
• an input for receiving a manipulation command to move the end effector with a desired end effector movement, the input being disposed on a user interface,
• a processor coupling the reconfiguration input to the manipulator arm, the processor being configured to:
• calculate an end effector displacing movement of the joints in response to the manipulation command to effect the desired end effector movement, wherein calculating the end effector displacing movement of the joints comprises calculating joint velocities within a null-perpendicular-space of the Jacobian;
• and
• calculate a cancellation movement for the plurality of joints that cancels the end effector displacing movement for each joint of the non-moving subset of joints, wherein calculating the cancellation movement comprises calculating joint velocities within a null-space of the Jacobian, the null-perpendicular-space being orthogonal to the null-space, wherein the non-moving subset includes one or more joints of the plurality.