Monitoring torsion on a distal end assembly
Apparatus for measuring a torque, consisting of a probe having a shaft with a shaft distal end. The probe has a distal end assembly, configured to be inserted into an organ of a human subject, and having a distal termination and a proximal termination connected to the shaft distal end. A position sensor assembly is attached to the distal end assembly in proximity to the distal termination, the position sensor assembly being configured to provide signals indicative of a three-dimensional position and orientation of the distal termination with respect to the shaft distal end. A processor is configured to compute a torsion of the distal termination with respect to the proximal termination in response to the signals from the position sensor assembly, and compute the torque on the distal end assembly in response to the torsion and a predetermined correspondence between the torsion and the torque.
1 . Apparatus for measuring a torque, comprising:
a probe, comprising:
a shaft having a shaft distal end,
a distal end assembly, configured to be inserted into an organ of a human subject, the distal end assembly having:
a distal termination,
a proximal termination connected to the shaft distal end, and
a longitudinal axis extending from the proximal termination to the distal termination, and
a position sensor assembly, attached to the distal end assembly in proximity to the distal termination thereof, the position sensor assembly being configured to provide signals indicative of a three-dimensional (3D) position and orientation of the distal termination with respect to the shaft distal end; and
a processor, configured to:
compute a torsion of the distal termination with respect to the proximal termination, about the longitudinal axis, in response to the signals from the position sensor assembly, and
compute the torque on the distal end assembly, about the longitudinal axis, in response to the torsion and a predetermined correspondence between the torsion and the torque on the distal end assembly.
2 . The apparatus according to claim 1 , further comprising a shaft position sensor, attached to the shaft distal end, configured to provide a signal indicative of an orientation of the shaft, the processor being configured to compute the torsion in relation to the orientation of the shaft.
3 . The apparatus according to claim 1 , further comprising a magnetic field generator attached to the shaft distal end, and the signals from the position sensor assembly being generated in response to a magnetic field from the generator, and the processor being configured to compute the torsion in relation to the orientation of the shaft.
4 . The apparatus according to claim 1 , the predetermined correspondence being based on modeling the distal end assembly as an elastic assembly.
5 . The apparatus according to claim 1 , further comprising a plurality of electrodes attached to the distal end assembly, the processor being further configured to:
identify electrodes contacting tissue of the organ,
evaluate a number of the contacting electrodes, and
compute a torque on a given electrode of the contacting electrodes in response to the number and the torque on the distal end assembly.
6 . The apparatus according to claim 5 , the processor being further configured to:
determine a distance of the given electrode to the longitudinal axis, and
compute a magnitude of a force on the given electrode in response to the torque on the given electrode and the distance.
7 . The apparatus according to claim 5 , the processor being further configured to:
determine a vector from the given electrode to the longitudinal axis, and
compute a direction of a force on the given electrode in response to the vector and an orientation of the longitudinal axis.
8 . The apparatus according to claim 5 , the processor being configured to determine a force on the given electrode in response to the given electrode pressing on the tissue in a non-torsional manner.
9 . The apparatus according to claim 1 , the distal end assembly comprising a balloon.
10 . The apparatus according to claim 1 , the distal end assembly comprising a plurality of splines.
11 . A method for measuring a torque, comprising:
providing a probe, comprising:
a shaft having a shaft distal end,
a distal end assembly, configured to be inserted into an organ of a human subject, the distal end assembly having:
a distal termination,
a proximal termination connected to the shaft distal end, and
a longitudinal axis extending from the proximal termination to the distal termination, and
a position sensor assembly, attached to the distal end assembly in proximity to the distal termination thereof, the position sensor assembly being configured to provide signals indicative of a three-dimensional (3D) position and orientation of the distal termination with respect to the shaft distal end;
computing a torsion of the distal termination with respect to the proximal termination, about the longitudinal axis, in response to the signals from the position sensor assembly; and
computing the torque on the distal end assembly, about the longitudinal axis, in response to the torsion and a predetermined correspondence between the torsion and the torque on the distal end assembly.
12 . The method according to claim 11 , the shaft further including a shaft position sensor, the shaft position sensor being configured to provide a signal indicative of an orientation of the shaft, the method further comprising computing the torsion in relation to the orientation of the shaft.
13 . The method according to claim 11 , the shaft further including a distal end with a magnetic field generator, the signals from the position sensor assembly being generated in response to a magnetic field from the magnetic field generator, the method further comprising computing the torsion in relation to the orientation of the shaft.
14 . The method according to claim 11 , the predetermined correspondence being based on modeling the distal end assembly as an elastic assembly.
15 . The method according to claim 11 , the distal end assembly further including a plurality of electrodes, the method further comprising:
identifying electrodes contacting tissue of the organ,
evaluating a number of the contacting electrodes, and
computing a torque on a given electrode of the contacting electrodes in response to the number and the torque on the distal end assembly.
16 . The method according to claim 15 , further comprising:
determining a distance of the given electrode to the longitudinal axis, and
computing a magnitude of a force on the given electrode in response to the torque on the given electrode and the distance.
17 . The method according to claim 15 , further comprising:
determining a vector from the given electrode to the longitudinal axis, and
computing a direction of a force on the given electrode in response to the vector and an orientation of the longitudinal axis.
18 . The method according to claim 15 , further comprising determining a force on the given electrode in response to the given electrode pressing on the tissue in a non-torsional manner.
19 . The method according to claim 11 , the distal end assembly comprising a balloon.
20 . The method according to claim 11 , the distal end assembly comprising a plurality of splines.