Position detection system for detecting position of object

1. A position detection system for detecting a position of an object having a recess or a protrusion, the position detection system comprising:

a contactor including an end configured to physically contact, trace and fit with the recess or the protrusion of the object;

a sliding mechanism that causes the contactor to slide in two directions perpendicular to each other;

a robot configured to cause the contactor to move in a direction perpendicular to a plane defined by the two directions so as to cause the end of the contactor to physically contact, trace and fit with the recess or the protrusion of the object;

a camera in a fixed positional relationship to a base of the sliding mechanism and configured to detect a position of the contactor in the plane; and

a controller configured to detect the position of the object based on a movement amount of the contactor before and after the contactor slides on the sliding mechanism when the end of the contactor physically traces the recess or the protrusion of the object.

2. The position detection system according to claim 1 , wherein, when the contactor is moved by the robot in at least one of the two directions, the controller is configured to detect the position of the object based on (i) the movement amount of the contactor by the robot and (ii) the movement amount of the contactor by the sliding mechanism.

3. The position detection system according to claim 1 , wherein the object has a recess, and the end of the contactor is a cone fittable with the recess.

4. The position detection system according to claim 1 , wherein the object has a conical protrusion, and the end of the contactor has a cylindrical portion fittable with the protrusion.

5. The position detection system according to claim 1 , wherein the controller is configured to detect the position of the object based on an image of the contactor, said image captured by the camera.

6. The position detection system according to claim 1 , wherein the controller is configured to detect the position of the object based on a single image of the contactor, said single image captured by the camera when the end of the contactor physically fits with the recess or the protrusion of the object.

7. The position detection system according to claim 1 , wherein the controller is configured to detect the position of the object by comparing first and second images of the contactor,

said first image captured by the camera when the contactor is at a location over the object but the end of the contactor does not yet physically fit with the recess or the protrusion of the object, and

said second image captured by the camera when the end of the contactor physically fits with the recess or the protrusion of the object.

8. The position detection system according to claim 1 , wherein

at least one of the sliding mechanism or the robot is configured to cause the contactor to move relative to the object to a location where the contactor is over the object but the end of the contactor does not yet physically fit with the recess or the protrusion of the object, and then

the robot is configured to move the contactor from said location only downwardly in the direction perpendicular to said plane, while enabling the contactor to slide in said two directions as the end of the contactor physically contacts, traces and eventually fits with the recess or the protrusion of the object.

9. The position detection system according to claim 8 , wherein the controller is configured to detect the position of the object based on a single image of the contactor, said single image captured by the camera when the end of the contactor physically fits with the recess or the protrusion of the object.

10. The position detection system according to claim 8 , wherein the controller is configured to detect the position of the object by comparing first and second images of the contactor,

said first image captured by the camera when the contactor is at said location over the object but the end of the contactor does not yet physically fit with the recess or the protrusion of the object, and

said second image captured by the camera when the end of the contactor physically fits with the recess or the protrusion of the object.

11. The position detection system according to claim 1 , wherein

the contactor has, on a surface facing the camera, a target, and

the controller is configured to detect the position of the object based on an image of the target, said image captured by the camera.

12. A position detection system for detecting a position of an object having a recess or a protrusion, comprising:

a contactor including an end that traces and fits with the recess or the protrusion of the object;

a sliding mechanism that causes the contactor to slide in two directions perpendicular to each other;

a robot that causes the contactor to move in a direction perpendicular to a plane defined between the two directions so as to cause the end of the contactor to trace and fit with the recess or the protrusion of the object;

a camera that is in a fixed positional relationship to a base of the sliding mechanism and detects a position of the contactor in the plane; and

a controller that detects the position of the object based on movement amount of the contactor before and after the contactor slides on the sliding mechanism when the end of the contactor traces the recess or the protrusion of the object.