Probe guiding
A techniques for improved guiding of hyper-redundant manipulator probes into a constrained space which make use of the known characteristics of the space into which the probe is being inserted to increase the efficiency of the computation of the path of the probe. Embodiments of the invention achieve this through an optimisation function which determined a new orientation which minimises the deviation between each of: a) the point on the probe where the probe starts to follow a defined curve within the constrained space and a predetermined initial point, and b) the distal end of the probe and said defined curve.
1. A method for guiding a probe inside a constrained space ( 16 ), wherein the probe is a hyper-redundant manipulator ( 30 ) comprising a plurality of independently-orientable connected segments ( 33 ) extendable between a proximal end and a distal end inside the constrained space, the method including the steps of:
determining: an initial point (pi) where the probe intersects a predetermined curve (C) which defines a circle or part circle within said constrained space; and an initial bend for the probe between an entry point ( 40 ) on a surface of the constrained space and the initial point;
and, repeatedly:
determining a new orientation of said segments which results in an advancement of the distal end to a new position which is on said curve, the new orientation being determined so as to minimise a deviation between each of: a) a point on the probe where the probe starts to follow said curve and the initial point, and b) a point (p 2 ) on the probe closer to the distal end than the point where the probe starts to follow said curve; and
adjusting an orientation of said segments to said new orientation and advancing the probe so that the distal end is located at the new position.
2. A method according to claim 1 wherein the steps of determining the new orientation and adjusting the manipulator are performed in real-time or substantially in real-time.
3. A method according to claim 1 wherein the constrained space is toroidal.
4. A method according to claim 1 wherein the curve defines a mid point of the space.
5. A probe system for accessing a constrained space ( 16 ), the probe system comprising:
a hyper-redundant manipulator ( 30 ) having a plurality of independently-orientable connected segments ( 33 ) extendable between a proximal end and a distal end; and
a controller,
wherein the controller is arranged to control the orientation of said segments so as to position the distal end in a desired position by:
determining: an initial point (pi) where the probe intersects a predetermined curve (C) which defines a circle or part circle within said constrained space, and an initial bend for the probe between an entry point ( 40 ) on a surface of the constrained space and the initial point;
and, repeatedly:
determining a new orientation of said segments which results in an advancement of the distal end to a new position which is on said curve, the new orientation being determined so as to minimise a deviation between each of: a) a point on the probe where the probe starts to follow said curve and the initial point, and b) a point (p 2 ) on the probe closer to the distal end than the point where the probe starts to follow said curve; and
sending actuation signals to the manipulator so to as to cause adjustment of an orientation of said segments to said new orientation and advance the probe so that the distal end is located at the new position.
6. A probe system according to claim 5 wherein the controller performs the steps of determining the new orientation and adjusting the manipulator in real-time or substantially in real-time.
7. A probe system according to claim 5 further including an end-effector ( 34 ) at the distal end of the manipulator.
8. A probe system according to claim 5 wherein the constrained space is toroidal.
9. A probe system according to claim 5 wherein the curve defines a mid point of the space.
10. A probe system according to claim 5 further including a feed-in mechanism ( 38 ) for advancing the probe.
11. A probe system according to claim 5 further including an actuation mechanism located at or near the proximal end, the actuation mechanism either being linked to actuators on each segment or arranged to directly drive the motion of each segment.