JP-2022530755-A5 -

Dates

Publication Date

20230515

Application Date

20210329

Description

According to a first aspect of the present invention, a control system for a surgical robot arm is provided, wherein the surgical robot arm comprises a series of joints that can change the configuration of the surgical robot arm, and one or more torque sensors, each torque sensor configured to detect the torque of one of the joints, and the control system is configured to control the configuration of the surgical robot arm, which is changed in response to an externally applied force or torque, by receiving sensory data from one or more torque sensors indicating the detected torque state of the surgical robot arm due to the externally applied force or torque, mapping the detected torque state to a selected torque state from a set of candidate torque states, and driving the robot arm by transmitting a command signal to the surgical robot arm so that the configuration of the robot arm is changed to conform to the selected torque state. The control system may be further configured to iteratively perform a control loop, which includes receiving, mapping , and transmitting steps. Each torque state in the set of candidate torque states may also be an element of the image of the Jacobian matrix. The control system may be configured to calculate the determinant of a second Jacobian matrix to estimate the current configuration of the surgical robotic arm, interpolate between a force acting at a single point on the robotic arm determined using the first Jacobian matrix and forces acting at the same point at n points on the robotic arm determined using the second Jacobian matrix, wherein the force is weighted depending on the calculated determinant of the second Jacobian matrix, and control the configuration of the surgical robotic arm, which is modified in response to an externally applied force or torque, according to the interpolated force. The control system may be further configured to use the Moore-Penrose pseudo-inverse of the Jacobian matrix to map the detected torque state to a selected torque state and to determine one or more forces corresponding to the selected torque state. A second aspect of the present invention provides a method for controlling a surgical robot arm, the surgical robot arm comprising a series of joints that can change the configuration of the surgical robot arm, and one or more torque sensors, each torque sensor configured to detect the torque of one of the joints, the method comprising controlling the configuration of the surgical robot arm, which is changed in response to an externally applied force or torque, by receiving sensory data from one or more torque sensors indicating a detected torque state of the surgical robot arm resulting from an externally applied force or torque, mapping the detected torque state to a selected torque state from a set of candidate torque states, and driving the robot arm by transmitting a command signal to the surgical robot arm so that the configuration of the robot arm is changed to conform to the selected torque state. This shows a typical surgical robotic system.This shows a surgical robotic system.This shows the surgical robotic arm of a surgical robotic system.This flowchart illustrates a first control loop implemented by a control system to change the configuration of a surgical robot arm in response to an externally applied force or torque.This flowchart illustrates a second control loop implemented by the control system to change the configuration of the surgical robot arm in response to an externally applied force or torque.This is a schematic diagram illustrating how the detected torque state is mapped in two dimensions to a selected torque state from a set of candidate torque states.This flowchart illustrates the control loop implemented by the control system to change the configuration of the surgical robot arm in response to an externally applied force or torque during instrument retrieval mode. In step 502, the detected torque state is mapped to a selected torque state from a set of candidate torque states. The set of candidate torque states may be a set of acceptable torque states for the robot arm. The set of candidate torque states may be encoded by a function. The set of candidate torque states may be predetermined. Figure 6 is a schematic diagram 600 showing that the detected torque state 602 is mapped in two dimensions to a selected torque state 601 from a set of candidate torque states 601. In Figure 6, the set of candidate torque states is encoded by a linear function 601. The detected torque state 602 is not a solution to the linear function 601, but rather, for example, outside the set of states to which the function is mapped . The detected torque state 602 is mapped or projected to the nearest torque state, which is a solution to its linear function 601, in this case the selected torque state 603. The selected torque state 603 may be a torque state in the set of candidate torque states that has the lowest Euclidean or least-sq