MOBILE COLLABORATIVE ROBOT

• US 20160031086A1
• Filed: 07/29/2015
• Published: 02/04/2016
• Est. Priority Date: 07/31/2014
• Status: Active Grant

• Current Assignee: Fanuc Corporation
• Original Assignee: Fanuc Corporation
• Inventors: TANABE, Yoshikiyo, HASHIMOTO, Yoshiki
• Granted Patent: US 9,669,548 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B25J 13/085 Force or torque sensors B25J13/082, B25J13/084 take precedence
• CPC Class Codes: B25J 13/088 with position, velocity or acceleration sensors
• CPC Class Codes: B25J 19/0075 Means for protecting the manipulator from its environment or vice versa
• CPC Class Codes: B25J 19/06 Safety devices
• CPC Class Codes: B25J 5/007 mounted on wheels
• CPC Class Codes: B25J 9/1694 characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception control, multi-sensor controlled systems, sensor fusion
• CPC Class Codes: Y10S 901/01 Mobile robot
• CPC Class Codes: Y10S 901/02 Arm motion controller
• CPC Class Codes: Y10S 901/46 Sensing device
• CPC Class Codes: Y10S 901/50 Miscellaneous

Abstract

A mobile collaborative robot includes a force sensor which is provided on a robot support on a carriage, a robot information acquisition unit which acquires robot information including posture information of the robot main body and load information of a load acting on the robot main body, a force calculation unit which calculates the external force acting on the robot support based on the robot information, and a judgment unit which judges that the mobile collaborative robot has come into contact with a human when a difference between the external force detected by the force sensor and the external force calculated by the force calculation unit is above a predetermined value α or when a difference between the amount of change in the detected external force and the amount of change in the calculated external force is above a predetermined value α1.

Claims

1. A mobile collaborative robot which carries out tasks in cooperation with a human, comprising

a carriage which has a robot support and which is moved by driving a first actuator,

a robot main body which is supported by the robot support on the carriage and which is operated by driving a second actuator,

a force sensor which is provided on the robot support to detect an external force acting on the robot support,

a robot information acquisition unit which acquires robot information including posture information of the robot main body and load information of a load acting on the robot main body,

a force calculation unit which calculates the external force acting on the robot support based on the robot information acquired by the robot information acquisition unit, and

a judgment unit which judges that the mobile collaborative robot has made contact with a human when a difference between the external force detected by the force sensor and the external force calculated by the force calculation unit is above a predetermined value or when a difference between the amount of change in the external force detected by the force sensor and the amount of change in the external force calculated by the force calculation unit is above a predetermined value.

2. A mobile collaborative robot according to claim 1, further comprising

an acceleration sensor which is provided on the carriage to detect an acceleration of the carriage, and

a correction unit which corrects the external force detected by the force sensor based on the acceleration detected by the acceleration sensor,

wherein the judgment unit judges that the mobile collaborative robot has made contact with a human when a difference between the external force corrected by the correction unit and the external force calculated by the force calculation unit is above a predetermined value or when a difference between the amount of change in the external force corrected by the correction unit and the amount of change in the external force calculated by the force calculation unit is above a predetermined value.

3. A mobile collaborative robot according to claim 1, further comprising

an outer casing which is secured to the robot support and covers the carriage, and

a protection member which covers the outer casing and the robot main body and has a rigidity lower than the outer casing,

wherein the force sensor detects the external force acting on the robot support through the protection member and the outer casing.

4. A mobile collaborative robot according to claim 1, further comprising a controller which controls the first actuator and the second actuator to stop the operation of the carriage and the robot main body when the judgment unit judges that the mobile collaborative robot has made contact with a human.

5. A mobile collaborative robot according to claim 4, wherein

the force sensor detects the external force acting on the robot support at least in the horizontal direction,

the force calculation unit calculates the external force acting on the robot support at least in the horizontal direction based on the robot information acquired by the robot information acquisition unit,

the predetermined value is a first predetermined value and a second predetermined value which is smaller than the first predetermined value is set in advance,

the controller controls the first actuator and the second actuator to move the carriage or the robot main body in a horizontal direction to reduce the external force detected by the force sensor when a difference between the external force detected by the force sensor in the horizontal direction and the external force calculated by the force calculation unit in the horizontal direction is above the second predetermined value but below the first predetermined value.

6. A mobile collaborative robot according to claim 4, wherein

the force sensor has a first force sensor and a second force sensor which are arranged to output identical values,

the mobile collaborative robot comprises a first CPU to which a signal from the first force sensor is input and a second CPU to which a signal from the second force sensor is input,

said first and second CPUs being configured to mutually monitor the output value of the signal from the first force sensor and the output value of the signal from the second force sensor to judge whether the difference therebetween is above a predetermined value,

the controller is provided on at least one of the first and second CPUs and controls the first actuator and the second actuator to stop the carriage and the robot main body when the first and second CPUs judge that a difference between the output value of the signal from the first force sensor and the output value of the signal from the second force sensor is above the predetermined value.

7. A mobile collaborative robot according to claim 4, further comprising an intrusion detection unit which detects

an intrusion of a human in the operation range of the mobile collaborative robot,

wherein when no intrusion of a human is detected by the intrusion detection unit, the controller controls the first actuator and the second actuator so that the maximum speed of the robot main body and the carriage is identical to a first speed, and when an intrusion of a human is detected by the intrusion detection unit, the controller controls the first and second actuators so that the maximum speed of the carriage and the robot main body is identical to a second speed which is lower than the first speed.

8. A mobile collaborative robot according to claim 4, further comprising

a power supply battery, and

a communication unit which wirelessly communicates with the outside of the mobile collaborative robot,

wherein

the carriage has a plurality of wheels by which the carriage is movable in the horizontal directions,

the judgment unit and the controller are included in a control unit,

the control unit, the battery and the communication unit are provided on the carriage.

9. A mobile collaborative robot according to claim 4, wherein

the carriage is provided on a horizontally extending rail so as to move therealong,

the judgment unit and the controller are included in a control unit arranged apart from the carriage,

the control unit is connected to the carriage and the robot main body through a cable.

10. A mobile collaborative robot which carries out tasks in cooperation with a human, comprising

a robot main body which is supported by a robot support and which is operated by driving an actuator,

a force sensor which is provided on the robot support to detect an external force acting on the robot support,

a robot information acquisition unit which acquires robot information including posture information of the robot main body and load information of a load acting on the robot main body,

a force calculation unit which calculates the external force acting on the robot support based on the robot information acquired by the robot information acquisition unit,

an acceleration sensor which is provided on the robot support to detect an acceleration generated in the robot support,

a correction unit which corrects the external force detected by the force sensor based on the acceleration detected by the acceleration sensor, and

a judgment unit which judges that the mobile collaborative robot has made contact with a human when a difference between the external force corrected by the correction unit and the external force calculated by the force calculation unit is above a predetermined value or when a difference between the amount of change in the external force corrected by the correction unit and the amount of change in the external force calculated by the force calculation unit is above a predetermined value.