Flexible tube insertion apparatus comprising insertion section to be inserted into subject and method of operating thereof

1. A flexible tube insertion apparatus comprising:

a flexible insertion section configured to be inserted into a subject;

an insertion section state detecting sensor configured to detect a current state of the insertion section as detection information when the insertion section is inserted into a subject; and

at least one controller configured to:

predict, using the detection information, a future propulsion state of a distal end of the insertion section and a corresponding state of the subject if the insertion section is further advanced in the subject from the current state of the insertion section; and

produce an output based on the prediction;

wherein the at least one controller predicts the propulsion state of the distal end of the insertion section and the corresponding state of the subject by one or more of:

using a calculation model of the insertion section and a calculation model of the subject, and

using the calculation model of the insertion section and the calculation model of the subject and an insertion pattern created based on past insertion data; and

the at least one controller estimates an external force applied to the insertion section from the subject, creates the calculation model of the subject based on the detection information and information on the estimated external force, and performs the prediction of the propulsion state of the distal end of the insertion section using the information on the external force and the calculation model of the subject.

2. The flexible tube insertion apparatus according to claim 1 , wherein the insertion section state detecting sensor comprises one or more of a shape detecting sensor configured to detect a shape of the insertion section, a strain detecting sensor configured to detect a bend or a strain of the insertion section, a contact force detecting sensor configured to detect a contact force of the insertion section against the subject.

3. The flexible tube insertion apparatus according to claim 1 , further comprising a memory that stores a value of viscoelasticity of the insertion section, wherein

the at least one controller creates an insertion section model based on information stored in the memory, and calculates an external force applied to the insertion section using the detection information and the insertion section model.

4. The flexible tube insertion apparatus according to claim 1 , wherein the output comprises a warning that informs an operator of one or more of a prediction result of the propulsion state and a change of the state of the insertion section to propel the distal end of the insertion section based on the prediction result of the propulsion state.

5. The flexible tube insertion apparatus according to claim 4 , wherein the warning informs the operator that the distal end of the insertion section is predicted to be in a stuck state with less propulsion force, by one or more of displaying characters, displaying an image, displaying a blinking, generating a vibration and generating a sound.

6. The flexible tube insertion apparatus according to claim 1 , wherein the output comprises changing one or more of at least a contact force between the subject and the insertion section, a contact angle and a frictional force.

7. The flexible tube insertion apparatus according to claim 1 , wherein the output comprises changing one or more of a bending stiffness of the insertion section, a bending angle of the insertion section, a weight distribution of the insertion section and one or more of the contact force and the contact angle of the insertion section against the subject.

8. The flexible tube insertion apparatus according to claim 7 , wherein the insertion section further comprises a plurality of variable stiffness materials configured to change the bending stiffness of at least a portion of the insertion section,

wherein the at least one controller is configured to change the bending stiffness of the variable stiffness material at a desired longitudinal position of the insertion section.