Flexible tube insertion apparatus, insertion control apparatus, and insertion control method

An insertion control apparatus comprising:

• a shape calculation system configured to calculate a shape of a flexible tube to be inserted into a tract of a target;
• a bend detection unit configured to detect formation of a first bend portion and a second bend portion in the flexible tube, based on information of the shape of the flexible tube calculated by the shape calculation system, the second bend portion being located on a proximal side of the flexible tube with respect to the first bend portion;
• a positional relationship calculation unit configured to calculate a three-dimensional positional relationship that is capable of being expressed by a crossing angle between a first imaginary plane passing through the first bend portion and a second imaginary plane passing through the second bend portion;
• and
• a stiffness control system configured to control a stiffness of the flexible tube, based on the three-dimensional positional relationship.

An insertion control method comprising:

• calculating a shape of a flexible tube to be inserted into a tract of a target;
• detecting formation of a first bend portion and a second bend portion in the flexible tube, based on information of the shape of the flexible tube, the second bend portion being located on a proximal side of the flexible tube with respect to the first bend portion;
• calculating a three-dimensional positional relationship that is capable of being expressed by a crossing angle between a first imaginary plane passing through the first bend portion and a second imaginary plane passing through the second bend portion;
• and
• controlling a stiffness of the flexible tube, based on the three-dimensional positional relationship.