Industrial robot and a method for controlling an industrial robot

Patent metadata

Field	Value
Publication number	US-2016129595-A1
Application number	US-201514928491-A
Country	US
Kind code	A1
Filing date	Oct 30, 2015
Priority date	Nov 7, 2014
Publication date	May 12, 2016
Grant date	—

Abstract

An industrial robot and control system including a high degree of cooperation between a human operator and the robot for increased safety. In an automatic operation mode, at least a first detection device detects the presence of a foreign body in the robot working area and the control system places the robot in a safe automatic operating mode. A second and third detection devices may be employed to detect possible impacts with the robot.

First claim

1 . An industrial robot comprising:
a manipulator with a number of degrees of freedom, having a mechanical structure comprising a plurality of movable parts, amongst which an end effector and one or more connection joints driven by electric motors with associated corresponding position transducers; a control unit of the manipulator, comprising selection means operable by a user for selection of a plurality of possible operating modes of the robot, amongst which at least one automatic operating mode; a first detection system, for detecting possible presence of a foreign body in a predefined working area of the manipulator, in particular a human being; a second detection system, comprising one or more inertial sensors installed on the manipulator; a third detection system, comprising means for measuring the torque applied by the electric motors; wherein implemented in the control unit is a program for control of the manipulator, the control program including relations that express theoretical values of position, speed, and acceleration of parts of the mechanical structure and relations that express theoretical values of torque applied by the electric motors; wherein the control unit is prearranged for driving the electric motors at working speeds determined by the control program at least in the automatic operating mode; wherein the control unit is prearranged in such a way that, with the robot in the automatic operating mode, detection by the first detection system of the presence of a foreign body within the predefined working area of the manipulator determines selection of a safe automatic operating mode of the robot; wherein, in the safe automatic operating mode, the control unit is operative for:
reducing the speeds of the electric motors to safety speeds determined by the control program, not higher than a speed threshold that is lower than the working speeds;
comparing theoretical acceleration values determined by the control program with acceleration values measured via the second detection system in order to detect a possible impulsive impact of the mechanical structure against a foreign body;
comparing theoretical values of torque determined by the control program with values of torque measured via the third detection system in order to detect a possible non-impulsive impact of the mechanical structure against a foreign body; and
in the case of detection of an impact of the mechanical structure against a foreign body, stopping the movement of the mechanical structure and/or governing reversal of the movement of the mechanical structure, in particular prior to arrest of the latter.

2 . The industrial robot according to claim 1 , wherein the one or more inertial sensors of the second detection system are selected from the group consisting of accelerometers and gyroscopes.

3 . The industrial robot according to claim 1 , wherein the first detection system comprises one or more devices selected from the group consisting of image-sensor devices, force-transducer devices, light-beam or light-barrier sensor devices, and radio frequency devices.

4 . The industrial robot according to claim 1 wherein the third detection system comprises means for measuring the electric current absorbed by the electric motors.

5 . The industrial robot according to claim 1 , wherein associated to one or more parts of the mechanical structure are covering elements, in particular ones having a yielding structure.

6 . The industrial robot according to claim 3 , wherein the first detection system comprises a radio frequency identification system.

7 . The industrial robot according to claim 6 , wherein the radio frequency identification system comprises a portable transponder, in particular configured for being carried by an operator, and a transponder reader installed in the predefined working area.

8 . The industrial robot according to claim 1 , wherein the control unit is prearranged for:
storing at least one of information representing acceleration values measured via the second detection system and information representing values of torque measured via the third detection system; and using said information for at least one of diagnostic purposes or purposes of verification of the operating state of the manipulator.

9 . The industrial robot according to claim 1 , wherein the speed threshold is not higher than 250 millimeters per second (mm/s).

10 . The industrial robot according to claim 1 , comprising at least two different first detection systems for detecting the possible presence of a human operator in a predefined working area of the manipulator, one of the two first detection systems including a radio frequency (RFID) arrangement.

11 . A method for controlling an industrial robot that comprises:
a manipulator with a number of degrees of freedom having a mechanical structure comprising a plurality of movable parts, amongst which an end effector and one or more connection joints driven by electric motors with associated corresponding position transducers; a control unit of the manipulator, comprising selection means that can be operated by a user for selection of a plurality of possible operating modes of the robot, amongst which at least one automatic operating mode; the method comprising: implementing in the control unit a program for control of the manipulator, the control program including relations that express theoretical values of position, speed, and acceleration of parts of the mechanical structure and relations that express theoretical values of torque applied by the electric motors; driving the electric motors at working speeds determined by the control program at least in the automatic operating mode; providing a first detection system for detecting possible presence of a foreign body within a predefined working area of the manipulator, in particular a human being; providing a second detection system, comprising one or more inertial sensors installed on the manipulator; providing a third detection system, comprising means for measuring the torque applied by the electric motors, wherein, with the robot in the automatic operating mode, the control unit selects a safe automatic operating mode following upon detection, by the first detection system, of the presence of a foreign body within the predefined working area of the manipulator; wherein, in the safe automatic operating mode, the control unit method comprising the steps of:
reducing the speeds of the electric motors to safety speeds determined by the control program, not higher than a speed threshold that is lower than the working speeds;
comparing theoretical acceleration values determined by the control program with effective acceleration values measured via the second detection system in order to detect a possible impulsive impact of the mechanical structure against a foreign body; and
comparing theoretical values of torque determined by the control program with effective values of torque measured via the third detection system in order to detect a possible non-impulsive impact of the mechanical structure against a foreign body;
and wherein, in the case of detection of an impact between the mechanical structure and a foreign body, the control unit operable to at least one of stopping the movement of the mechanical structure, or governing reversal of the movement of the mechanical structure, in particular prior to arrest of the latter.

12 . An industrial robot control system comprising:
a manipulator having a plurality of electric motors and defining a predetermined work area; a control unit in electronic communication with the manipulator, the control unit having an automatic operating m

Assignees

• Comau Spa

Inventors

• Gerio Gian Paolo
• Wiklund Allan Mathias
• Baroncelli Arturo

Classifications

• B25J9/1676 Primary

  Avoiding collision or forbidden zones · CPC title

• B25J9/1674

  characterised by safety, monitoring, diagnostic · CPC title

• B25J19/063

  working only upon contact with an outside object · CPC title

• Y10S901/30

  End effector · CPC title

• B25J13/088

  with position, velocity or acceleration sensors · CPC title