Method for monitoring a machine and such a machine, particularly a robot

• US 7,086,293 B2
• Filed: 01/28/2004
• Issued: 08/08/2006
• Est. Priority Date: 02/01/2003
• Status: Active Grant

• Current Assignee: KUKA Roboter GmbH (Midea Group Co., Ltd)
• Original Assignee: KUKA Roboter GmbH (Midea Group Co., Ltd)
• Inventors: Settele, Norbert, Heiligensetzer, Peter, Berninger, Alwin
• Primary Examiner(s): NOORI, MAX H
• Application Number:
  US10/766,769
• Publication Number:
  US 20040260481A1
• Time in Patent Office: 923 Days
• Field of Search: 737/81, 73/11.5, 737/67, 737/74, 737/95, 737/63
• US Class Current: 73/795
• CPC Class Codes: B25J 9/1674 characterised by safety, monitoring, diagnostic
• CPC Class Codes: G05B 2219/40226 Input control signals to control system and to model, compare their outputs
• CPC Class Codes: G05B 2219/40228 If deviation of compliant tool is too large, stop and alarm
• CPC Class Codes: G05B 2219/40229 Analytical redundancy, use available funcional redundancy of model

Abstract

In order to improve the monitoring of a machine with movable parts, such as in particular an industrial robot, and for increasing safety, the invention provides a method for monitoring movable parts of a machine, such as an industrial robot, in which at least two different measured quantities are detected and at least one of these measured quantities is processed to a first measure result in such a way that it is comparable with another measured quantity or a second measure result obtained on the basis thereof, that the first measure result is compared with another measured quantity or a measure result obtained on the basis thereof and that a signal characterizing the comparison result is provided.

The invention also provides a machine with movable parts, such as in particular an industrial robot, which is characterized by at least two measuring devices for detecting different measured quantities on movable parts of the machine, a processing unit for at least one measured quantity for the processing thereof into a first measure result comparable with another measured quantity or a second measure result obtained therefrom and a comparison unit for comparing the first measure result with at least one other measured quantity or a second measure result obtained on the basis thereof.

Claims

1. A method for monitoring movable parts of an industrial robot machine, the method comprising the steps of:

providing a reference value or a reference corridor to a reference curve generated by a calculated reference result using a mathematical model in a calculation or by recording real measure values under known conditions without any interfering influences for the movable parts of the machine;

measuring physical material strains on parts of the machine by sensors or transducers arranged on the robot to arrive at a measured quantity;

comparing said measured quantity with said reference value prior to transforming into an actual measured value of said measured quantity; and

comparing said actual measured value of said measured quantities and/or calculated measured results with said reference value, whilst taking account of tolerances to arrive at a comparison result, wherein said comparison result produces information about either interference freedom or an unexpected event, including a collision.

2. A method for monitoring movable parts of an industrial robot machine according to claim 1, wherein measured values of at least two different physical quantities are measured and at least one of these measured values is processed to a first measure result in such a way that it is comparable with another measured value of another measured quantity or a second measure result obtained as a result thereof, that said first measure result is compared with said another measured value of said another measured quantity or said second measure result obtained as a result thereof and that a signal characterizing said comparison result is provided.

3. A method according to claim 1, wherein said material strains are measured by means of at least one transducer.

4. A method according to claim 1, wherein said material strains are measured by means of a strain gauge.

5. A method according to claim 1, wherein said material strains are measured by means of piezoelectric or light guide-based pickups.

6. A method according to claim 1, wherein said material strains are measured by means of a set of transducers positioned on at least two surfaces of a robot part.

7. A method according to claim 1, wherein said tolerances are taken into account by forming said reference corridor to said reference curve.

8. A method according to claim 1, wherein in the case of divergences from expected said reference values and/or calculated measured results, the machine is stopped or brought into a safe state.

9. A machine with movable parts for an industrial robot, the machine comprising:

a plurality of measuring devices for determining physical material strains; and

a comparison device for comparing actual measured values and/or calculated measure results with an expected reference value of predetermined models for robot movements, whilst taking account of tolerances, wherein said reference value or a reference corridor to a reference curve is generated by calculation using a mathematical model or by recording real measure values under known conditions without any interfering influences, an output of said comparison device giving information about either an interference from movement freedom or an unexpected event including a collision.

10. A machine according to claim 9, wherein at least two said measuring devices are provided for determining said material strains and a comparison device for comparing actual measured values and/or calculated measure results with predetermined models for robot movements, and a plurality of said measured value of at least two different measured quantities are detected and at least one of these measured values is processed to a first measure result in such a way that it is comparable with another measured value of another measured quantity or a second measure result obtained as a result thereof, that said first measure result is compared with said another measured value of said another measured quantity or said second measure result obtained as a result thereof and that a signal characterizing said comparison result is provided and said output of said comparison device giving information about an unexpected event including a collision.

11. A machine according to claim 9, wherein said devices for determining materials strains are constructed as transducers.

12. A machine according to claim 9, wherein said devices for determining material strains are constructed as strain gauges.

13. A machine according to claim 9, wherein said devices for determining material strains are constructed as light guide-based pickups.

14. A machine according to claim 9, wherein in each case at least one device for determining material strains is placed on at least two surfaces of a robot part.

15. A machine according to claim 9, wherein a monitoring device is provided to which is connected at least one device for determining material strains on machine parts.

16. A machine according to claim 15, wherein said monitoring device has a unit for monitoring at least elongations of said machine structure and another unit for monitoring a further measured quantity.

17. A machine according to claim 16, wherein said monitoring device has a device for disconnecting said machine.

18. A machine according to claim 9, wherein in the case of divergences from expected said reference value and/or calculated measure results, the machine is stopped or brought into a safe state.