Torque-based catheter articulation

Patent metadata

Field	Value
Publication number	US-2016015937-A1
Application number	US-201514867980-A
Country	US
Kind code	A1
Filing date	Sep 28, 2015
Priority date	Mar 14, 2013
Publication date	Jan 21, 2016
Grant date	—

Abstract

A robotic surgical system configured for the articulation of a catheter comprises an input device, a control computer, and an instrument driver having at least one motor for displacing the pull-wire of a steerable catheter wherein the control computer is configured to determine the desired motor torque or tension of the pull-wire of a catheter based on user manipulation of the input device. The control computer is configured to output the desired motor torque or tension of the pull-wire to the instrument driver, whereby at least one motor of the instrument driver implements the desired motor torque to cause the desired pull-wire tension to articulate the distal tip of the catheter. The present embodiment further contemplates a robotic surgical method for the articulation of a steerable catheter wherein an input device is manipulated to communicate a desired catheter position to a control computer and motor torque commands are outputted to an instrument driver. The robotic system may further comprise a torque sensor. The robotic system may also incorporate closed loop feedback in which data from the torque measuring device is used to ensure that the torque in the motor or tension in the pull-wire closely matches the motor torque command from the control computer.

First claim

What is claimed is:

1 . A robotic catheter system, configured to insert a catheter within an anatomical lumen of a patient, the catheter comprising a flexible shaft, an articulating distal tip, and an actuating pull-wire attached to the articulating distal tip and extending a length of the catheter, the robotic surgical system comprising:
a user input device configured to receive a commanded deflection of the distal articulating tip; an instrument driver having a motor; and a control system operatively connected to the input device and the instrument driver, the control system configured to translate the commanded deflection into a commanded motor torque value, wherein the motor is configured to apply the commanded motor torque value to adjust a tension in the pull-wire such that the articulating distal tip of the catheter reaches the commanded deflection, and wherein the robotic catheter system is further configured to detect a difference between the commanded motor torque value and an actual motor torque value and determine an adjustment needed to the commanded motor torque value to maintain a position of the articulating distal tip.

2 . The robotic catheter system of claim 1 , wherein the difference between the commanded motor torque value and the actual motor torque value is due to creep in the catheter shaft.

3 . The robotic catheter system of claim 1 , wherein the difference between the commanded motor torque value and the actual motor torque value is due to backlash in a drive transmission of the instrument driver.

4 . The robotic catheter system of claim 1 , wherein the difference between the commanded motor torque value and the actual motor torque value is due to a distal disturbance.

5 . The robotic catheter system of claim 4 , wherein the distal disturbance is due to additional stiffness in the catheter caused by a therapeutic device being delivered through the catheter.

6 . The robotic catheter system of claim 4 , wherein the distal disturbance is due to the articulating distal tip contacting a surface external to the catheter.

7 . The robotic catheter system of claim 4 , wherein the robotic catheter system is configured to present information of the distal disturbance to the user as haptic or visual feedback.

8 . The robotic catheter system of claim 1 , wherein the catheter comprises a plurality of actuating pull-wires.

9 . The robotic catheter system of claim 8 , wherein the control system is further configured to increase an effective stiffness of the catheter by commanding a simultaneous increase in tension in the plurality of pull-wires.

10 . The robotic catheter system of claim 1 , wherein the control system is configured to translate the commanded deflection into the commanded motor torque value based on a model of catheter stiffness.

11 . The robotic catheter system of claim 10 , wherein the control system is configured to determine the adjustment needed to the commanded motor torque value by adjusting, in the model of catheter stiffness, a spring rate of the catheter shaft based on the difference between the commanded motor torque value and the commanded torque value.

12 . The robotic catheter system of claim 1 , further comprising a torque sensor configured to sense the actual motor torque.

13 . The robotic catheter system of claim 1 , further comprising a strain gauge configured to measure force on the pull-wire.

14 . The robotic catheter system of claim 1 , wherein control system is configured to translate the commanded deflection into the commanded motor torque value by translating the commanded deflection into a commanded pull-wire tension and translating the commanded pull-wire tension into the commanded motor torque value.

15 . The robotic catheter system of claim 1 , wherein the instrument driver is configured to limit a maximum tension applied to the pull-wire.

16 . The system of claim 1 , wherein the instrument driver is configured to adjust the commanded motor torque value to ensure the articulating distal tip is articulated at a constant force.

17 . The system of claim 1 , wherein the commanded deflection is a commanded deflection angle.

18 . The system of claim 1 , wherein the commanded deflection is a commanded catheter orientation.

19 . The system of claim 1 , further comprising a motor servo, wherein the motor servo is configured to detect the difference between the commanded motor torque value and the actual motor torque value and adjust an electrical current to the motor in order to adjust the actual motor torque value to maintain the position of the articulating distal tip.

20 . The system of claim 1 , wherein the instrument driver is configured to rotate the motor in accord with both the commanded motor torque value and a motor angular displacement output from the control system.

Assignees

• Hansen Medical Inc

Inventors

• Hart J Scot
• Macnamara Francis

Classifications

• A61B34/30

  Surgical robots · CPC title

• A61B34/37

  Leader-follower robots (A61B34/35 takes precedence) · CPC title

• A61M2205/332

  Force measuring means · CPC title

• A61B2090/031

  torque limiting · CPC title

• A61B90/03

  Automatic limiting or abutting means, e.g. for safety · CPC title