Inverse kinematic control systems for robotic surgical system

Abstract

A method of using inverse kinematics to control a robotic system includes receiving an input pose from a user interface to move an arm of the robotic system, calculating a remote center of motion for a desired pose from the input pose in a tool center-point frame, checking when the desire pose needs correction, correcting the desired pose of the arm, and moving the arm to the desired pose in response to the input pose. The arm of the robotic system including a tool having a jaw disposed at an end of the arm. Checking when the desired pose needs correction includes verifying that the remote center of motion is at or beyond a boundary distance in the desired pose. Correcting the desired pose of the arm occurs when the remote center of motion is within the boundary distance.

What is claimed: 
     
         1 . A method of controlling a robotic system, the method comprising:
 receiving an input pose from a user interface to move an arm of the robotic system, wherein a tool having a jaw is disposed at the end of the arm, the jaw defining a jaw axis;   calculating a remote center of motion for a desired pose from the input pose in a tool center-point frame;   checking when the desired pose needs correction by verifying the remote center of motion is at or beyond a boundary distance in the desired pose;   correcting the desired pose of the arm when the remote center of motion is within the boundary distance; and   moving the arm to the desired pose in response to the input pose.   
     
     
         2 . The method according to  claim 1 , wherein during correcting the desired pose of the arm, the jaw axis is held in position. 
     
     
         3 . The method according to  claim 1 , wherein correcting the desired pose of the arm includes moving the remote center of motion to the boundary distance. 
     
     
         4 . The method according to  claim 1 , wherein determining the boundary distance as a function of a maximum joint angle of a pitch joint between the tool and the distance between the origin of the tool center-point and the pitch joint. 
     
     
         5 . The method according to  claim 4 , wherein the maximum joint angle of the pitch joint is 75°. 
     
     
         6 . The method according to  claim 4 , wherein determining the boundary distance includes taking the sum of the distance between the origin of the tool center-point and the pitch joint and the cosine of the maximum joint angle of the pitch joint. 
     
     
         7 . The method according to  claim 5 , wherein the boundary distance is taken along the jaw axis. 
     
     
         8 . The method according to  claim 1 , further comprising providing feedback when the remote center of motion approaches the boundary distance. 
     
     
         9 . The method according to  claim 8 , wherein providing feedback when the remote center of motion approaches the boundary distance includes increasing the feedback as the remote center of motion approaches the boundary distance. 
     
     
         10 . The method according to  claim 9 , wherein increasing the feedback includes linearly increasing the feedback. 
     
     
         11 . The method according to  claim 9 , wherein increasing the feedback includes exponentially increasing the feedback. 
     
     
         12 . The method according to  claim 9 , wherein increasing the feedback includes linearly increasing the feedback as the remote center of motion approaches the boundary distance and exponentially increasing the feedback as the remote center of motion crosses the boundary distance. 
     
     
         13 . The method according to  claim 1 , further comprising determining a check angle defined between the jaw axis and a vector between an origin of the tool center-point frame and the remote center of motion when the remote center of motion is within the boundary distance. 
     
     
         14 . The method according to  claim 13 , further comprising providing feedback when the check angle is below a predefined extreme angle. 
     
     
         15 . A robotic surgical system comprising:
 a processing unit;   a user interface in communication with the processing unit and including an input handle; and   a robotic system in communication with the processing unit and including an arm and a tool supported at an end of the arm, the arm defining a remote center of motion and the tool defining a tool center-point frame, the arm and the tool configured to move to a desired pose in response to an input pose of the input handle,   wherein the processing unit is configured to verify the remote center of motion being within the boundary distance in the desired pose, and wherein the processing unit is configured to correct the desired pose when the remote center of motion is within the boundary distance.   
     
     
         16 . The robotic surgical system according to  claim 15 , wherein the processing unit is configured to verify that a check angle defined between the jaw axis and a vector between an origin of the tool center-point frame and the remote center of motion is below a predefined extreme angle when the remote center of motion is within the boundary distance in the desired pose. 
     
     
         17 . The robotic surgical system according to  claim 16 , wherein the user interface is configured to provide feedback to a clinician when the check angle is below the predefined extreme angle. 
     
     
         18 . The robotic surgical system according to  claim 15 , wherein the input handle is configured to provide force feedback to a clinician as the remote center of motion approaches the boundary distance in the desired pose.