Apparatus and method for detecting contact position of robot

1. An apparatus for detecting a contact position where a robot makes contact with an object, the apparatus comprising:

a probe that is attached to the robot, the probe being configured to make a displacement in a direction of making contact with the object in an elastic manner;

a probe-position calculating unit configured to calculate a position of the probe of the robot in operation;

a contact detecting unit configured to detect a contact state of the probe with the object;

a contact-position calculating unit configured to, when the contact state of the probe is detected, derive the contact position based on a calculated position of the probe;

an external-force detecting unit configured to detect an external force applied to the probe; and

a recording unit configured to record therein the external force detected by the external-force detecting unit and the position of the probe calculated by the probe-position calculating unit in a time series manner, wherein

when the contact state of the probe is detected, the contact-position calculating unit obtains a contact time of the probe based on the external force recorded in the recording unit and derives a position of the probe at a recorded contact time as the contact position of the robot, and

the contact-position calculating unit obtains a time when a temporal change of a value of the external force recorded in the recording unit changes as the contact time.

2. The apparatus according to claim 1 , wherein

when the contact state of the probe is detected, the contact-position calculating unit obtains a contact start time of the probe based on the external force recorded in the recording unit and derives a position of the probe at the recorded contact start time as the contact position of the robot, and

the contact detecting unit determines that the probe is in the contact state when the external force applied to the probe exceeds a predetermined value.

3. The apparatus according to claim 1 , wherein a noise-reduction filtering process having a same temporal characteristic is performed on a detected external force and the calculated position of the probe.

4. The apparatus according to claim 1 , wherein the contact detecting unit is configured as a sensor that electrically detects the contact state by a current conduction.

5. The apparatus according to claim 1 , further comprising an upper-level controller that controls the robot, wherein

the robot includes servo motors and a motor control system that controls the servo motors based on an instruction from the upper-level controller,

the upper-level controller includes a built-in calculation model for simulating the motor control system, and

the probe-position calculating unit calculates the position of the probe by using an output value obtained when instruction data to the servo motors is input to the calculation model.

6. The apparatus according to claim 1 , wherein the probe is configured to be attached to the robot in a detachable manner or to be stored in the robot.

7. An apparatus for detecting a contact position where a robot makes contact with an object, the apparatus comprising:

a probe that is attached to the robot, the probe being configured to make a displacement in a direction of making contact with the object in an elastic manner;

probe-position calculating means for calculating a position of the probe of the robot in operation;

contact detecting means for detecting a contact state of the probe with the object;

contact-position calculating means for, when the contact state of the probe is detected, deriving the contact position based on a calculated position of the probe;

external-force detecting means for detecting an external force applied to the probe; and

recording means for recording therein the external force detected by the external-force detecting means and the position of the probe calculated by the probe-position calculating means in a time series manner, wherein

when the contact state of the probe is detected, the contact-position calculating means obtains a contact time of the probe based on the external force recorded in the recording means and derives a position of the probe at a recorded contact time as the contact position of the robot, and

the contact-position calculating means obtains a time when a temporal change of a value of the external force recorded in the recording means changes as the contact time.

8. A method for detecting a contact position of a robot, the method comprising:

attaching a probe that is configured to make a displacement in a direction of contacting with an object in an elastic manner to the robot;

performing a position control of the robot;

calculating a position of the probe;

detecting a contact state of the probe with the object;

decelerating and stopping, when the contact state of the probe is detected, the robot and deriving the contact position based on a calculated position of the probe;

detecting an external force applied to the probe; and

recording a detected external force and the calculated position of the probe in a time series manner, wherein

the detecting of the contact state of the probe with the object includes detecting the contact state of the probe based on the detected external force, and

when the contact state of the probe is detected, the deriving of the contact position includes obtaining a contact time of the probe based on a recorded external force and deriving a position of the probe at a recorded contact time as the contact position of the robot,

the detecting of the contact state of the probe with the object includes detecting that the probe is in the contact state when the external force applied to the probe exceeds a predetermined value, and

the predetermined value is set to a value larger than a force caused by a disturbance to the robot.

9. The method according to claim 8 , wherein

the detecting of the contact state of the probe with the object includes detecting the contact state electrically by a current conduction, and

the deriving the contact position includes deriving a position of the probe at a time when the contact state is detected by the current conduction as the contact position.

10. The apparatus according to claim 1 , further comprising a decelerating and stopping unit configured to control the robot to decelerate and stop when the contact state of the probe is detected.

11. The apparatus according to claim 2 , wherein the predetermined value is set to a value larger than a force caused by a disturbance to the robot.

12. The apparatus according to claim 11 , wherein the predetermined value is set to a value larger than a force generated when the probe is first brought into contact with the object.

13. The method according to claim 8 , wherein the predetermined value is set to a value larger than a force generated when the probe is first brought into contact with the object.

14. A non-transitory computer readable storage medium having stored therein a program for detecting a contact position of a robot that includes a probe that makes a displacement in a direction of contacting with an object in an elastic manner, the program causing a computer to execute a process comprising:

performing a position control of the robot;

calculating a position of the probe;

detecting a contact state of the probe with the object;

decelerating and stopping, when the contact state of the probe is detected, the robot and deriving the contact position based on a calculated position of the probe;

detecting an external force applied to the probe; and

recording a detected external force and the calculated position of the probe in a time series manner, wherein

the detecting of the contact state of the probe with the object includes detecting the contact state of the probe based on the detected external force, and

when the contact state of the probe is detected, the deriving of the contact position includes obtaining a contact time of the probe based on a recorded external force and deriving a position of the probe at a recorded contact time as the contact position of the robot,

the detecting of the contact state of the probe with the object includes detecting that the probe is in the contact state when the external force applied to the probe exceeds a predetermined value, and

the predetermined value is set to a value larger than a force caused by a disturbance to the robot.

15. An apparatus for detecting a contact position where a robot makes contact with an object, the apparatus comprising:

a probe that is attached to the robot, the probe being configured to make a displacement in a direction of making contact with the object in an elastic manner;

a probe-position calculating unit configured to calculate a position of the probe of the robot in operation;

a contact detecting unit configured to detect a contact state of the probe with the object;

a contact-position calculating unit configured to, when the contact state of the probe is detected, derive the contact position based on a calculated position of the probe;

an external-force detecting unit configured to detect an external force applied to the probe; and

a recording unit configured to record therein the external force detected by the external-force detecting unit and the position of the probe calculated by the probe-position calculating unit in a time series manner, wherein

when the contact state of the probe is detected, the contact-position calculating unit obtains a contact time of the probe based on the external force recorded in the recording unit and derives a position of the probe at a recorded contact time as the contact position of the robot,

when the contact state of the probe is detected, the contact-position calculating unit obtains a contact start time of the probe based on the external force recorded in the recording unit and derives a position of the probe at the recorded contact start time as the contact position of the robot,

the contact detecting unit determines that the probe is in the contact state when the external force applied to the probe exceeds a predetermined value, and

the predetermined value is set to a value larger than a force caused by a disturbance to the robot.