SAFETY MONITORING DEVICE FOR ROBOT GRIPPING AND CARRYING WORKPIECE

• US 20150314445A1
• Filed: 04/28/2015
• Published: 11/05/2015
• Est. Priority Date: 04/30/2014
• Status: Active Grant

• Current Assignee: Fanuc Corporation
• Original Assignee: Fanuc Corporation
• Inventors: Arita, Soichi, Takahashi, Hiromitsu, Naitou, Yasuhiro
• Granted Patent: US 9,682,478 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B25J 9/1674 characterised by safety, monitoring, diagnostic
• CPC Class Codes: B25J 9/1676 Avoiding collision or forbidden zones
• CPC Class Codes: G05B 2219/40582 Force sensor in robot fixture, base

Abstract

A safety monitoring device monitoring a robot includes a workpiece parameter switching unit switching a workpiece parameter, an external force estimation unit estimating, as an external force estimation value, a force acting on the robot from an external environment by using the workpiece parameter, an external force monitoring unit stopping the robot when the external force estimation value satisfies an external force determination condition, an operation monitoring unit stopping the robot, based on conditions such as a position of the robot being included within a predetermined region, an operation monitoring state switching unit switching between a disabling command and an enabling command for the operation monitoring unit, and an external force determination condition setting unit switching the external force determination condition to an operation monitoring disabling time external force determination condition at the disabling command and to an operation monitoring enabling time external force determination condition at the enabling command.

Claims

1. A safety monitoring device (RC) for monitoring a robot (R), provided with a force detection unit for detecting an external force acting on the robot, the robot safety monitoring device comprising:

a workpiece parameter switching unit (22) for switching a workpiece parameter including at least one of a mass, a center of mass, and an inertia matrix of a workpiece to be gripped by the robot;

an external force estimation unit (23) for estimating, as an external force estimation value, a force or a torque acting on the robot from an external environment by using the workpiece parameter switched by the workpiece parameter switching unit;

an external force monitoring unit (25) for stopping the robot when the external force estimation value satisfies an external force determination condition;

an operation monitoring unit (27) for stopping the robot when at least one of the following conditions is not satisfied;

a position of the robot is included within a predetermined region, a moving direction of the robot is a predetermined direction, an operation speed of the robot is equal to or slower than a predetermined speed, and an operation acceleration of the robot is equal to or smaller than a predetermined acceleration;

an operation monitoring state switching unit (24) for switching between an operation monitoring disabling command for disabling the operation monitoring unit and an operation monitoring enabling command for enabling the operation monitoring unit; and

an external force determination condition setting unit (25) for switching the external force determination condition to an operation monitoring disabling time external force determination condition when switched to the operation monitoring disabling command and switching the external force determination condition to an operation monitoring enabling time external force determination condition when switched to the operation monitoring enabling command.

2. The safety monitoring device according to claim 1, wherein the external force determination condition includes at least one of conditions that the external force estimation value exceeds a predetermined first value, a moving average of the external force estimation value exceeds a predetermined second value, and an amount of change between the external force estimation value before a predetermined time and the external force estimation value at present exceeds a predetermined third value.

3. The safety monitoring device according to claim 1, wherein when switched to the operation monitoring enabling command, the external force monitoring unit is adapted to be disabled.

4. The safety monitoring device according to claim 1, wherein the operation monitoring disabling time external force determination condition is a condition that the external force estimation value exceeds a first threshold value, and the operation monitoring enabling time external force determination condition is a condition that the external force estimation value exceeds a second threshold value more than the first threshold value.

5. The safety monitoring device according to claim 1, wherein when the external force estimation value estimated by the external force estimation unit does not satisfy a predetermined condition at a time when the operation monitoring state switching unit switches from the operation monitoring enabling command to the operation monitoring disabling command, the operation monitoring state switching unit stops switching from the operation monitoring enabling command to the operation monitoring disabling command.