Micro-force guided cooperative control for surgical manipulation of delicate tissue

A method of cooperative control of a surgical tool, comprising:

• providing a surgical tool to be manipulated during an operation;
• measuring interaction forces between the surgical tool and tissue of a region of interest;
• measuring interaction forces between a surgeon and a handle of the surgical tool;
• and
• actively guiding, by a cooperatively controlled robot, the surgical tool by creating a direction-dependent bias in the response of the cooperatively controlled robot to said measured interaction forces between said surgeon and said handle of said surgical tool based on said measured interaction forces between said surgical tool and tissue of said region of interest,
• wherein creating a direction-dependent bias comprises enforcing a minimum velocity according to
• {dot over (x)}min=kp(1−rtsmin)fh,
• where kp is a gain of the measured interaction forces between the tip of the surgical tool and the tissue of a region of interest;
• rt=|ft|/∥ft∥, where ft is the measured interaction forces between a tip of the surgical tool and the tissue of a region of interest;
• smin is a sensitivity of minimization that sets a ratio of the handle force to be locally minimized;
• and fh is the measured interaction forces between the surgeon and the handle to the surgical tool.

A cooperative control robotic system, comprising:

• a tool holder for receiving a surgical tool;
• a first sensor for measuring interaction forces between the surgical tool and tissue of a region of interest;
• a second sensor for measuring interaction forces between a surgeon and a handle of the surgical tool;
• and
• a cooperatively controlled robot configured to actively guide the surgical tool by creating a direction-dependent bias in a response of said cooperatively controlled robot to said measured interaction forces between said surgeon and said handle of said surgical tool based on said measured interaction forces between said surgical tool and tissue of said region of interest,
• wherein the cooperatively controlled robot is configured to actively guide the surgical tool by applying a limit on directional tool forces according to
• x
• .
• lim
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• wherein {dot over (x)} is the velocity, flim is a limit of the interaction forces between a tip of the surgical tool and the tissue of a region of interest, ft is the measured interaction forces between the tip of the surgical tool and the tissue of a region of interest, and wherein a virtual spring of length llim is used to ensure stability at the limit boundary.

A cooperative control robotic system, comprising:

• a tool holder for receiving a surgical tool;
• a first sensor for measuring interaction forces between the surgical tool and tissue of a region of interest;
• a second sensor for measuring interaction forces between a surgeon and a handle of the surgical tool;
• and
• a cooperatively controlled robot configured to actively guide the surgical tool by creating a direction-dependent bias in a response of said cooperatively controlled robot to said measured interaction forces between said surgeon and said handle of said surgical tool based on said measured interaction forces between said surgical tool and tissue of said region of interest,
• wherein the cooperatively controlled robot is configured to create a direction-dependent bias by enforcing a minimum velocity according to
• {dot over (x)}min=kp(1−rtsmin)fh,
• where kp is a gain of the measured interaction forces between the tip of the surgical tool and the tissue of a region of interest;
• rt=|ft|/∥ft∥, where ft is the measured interaction forces between a tip of the surgical tool and the tissue of a region of interest;
• smin is a sensitivity of minimization that sets a ratio of the handle force to be locally minimized;
• and fh is the measured interaction forces between the surgeon and the handle to the surgical tool.