OBJECT DETECTOR APPARATUS AND METHOD

• US 20100027031A1
• Filed: 12/10/2007
• Published: 02/04/2010
• Est. Priority Date: 12/21/2006
• Status: Active Grant

• Current Assignee: Renishaw PLC
• Original Assignee: Renishaw PLC
• Inventors: Barnard, William Martin, Davies, William Kenneth, Stimpson, Victor Gordon, Merrifield, Benjamin Jason
• Granted Patent: US 8,537,359 B2
• Time in Patent Office: Days
• US Class Current: 356/614
• CPC Class Codes: B23Q 17/24 using optics or electromagnetic waves

Abstract

An object detector apparatus. The object detector apparatus comprises a receiver which is configured to receive a signal from an object having a repetitive motion, in which the signal repeats at a frequency that is dependent on the frequency of the repetitive motion of the object. The object detector apparatus further comprises an analyser which is configured to sample a signal received by the receiver according to a first set of sampling parameters into a first sampled data set, and to produce an output based on a comparison of the first sampled data set with at least one previously sampled data set. The analyser is also operable to sample a signal received by the receiver using a second set of sampling parameters which differs to the first set of sampling parameters into a second sampled data set, and to produce an output based on a comparison of the second sampled data set with at least one previously sampled data set.

Claims

1. An object detector apparatus, comprising:

a receiver configured to receive a signal from an object having a repetitive motion, the signal repeating at a frequency that is dependent on the frequency of the repetitive motion of the object; and

an analyser being configured to sample a signal received by the receiver according to a first set of sampling parameters into a first sampled data set, and to produce an output based on a comparison of the first sampled data set with at least one previously sampled data set;

in which the analyser is operable to sample a signal received by the receiver using a second set of sampling parameters which differs to the first set of sampling parameters into a second sampled data set, and to produce an output based on a comparison of the second sampled data set with at least one previously sampled data set.

2. An object detector apparatus as claimed in claim 1, in which the signal sampled into the first sampled data set, is the same signal as the signal sampled into the second sampled data set.

3. An object detector apparatus as claimed in claim 2, in which the analyser is operable to sample the signal into the first sampled data set and to sample the signal into the second sampled data set substantially concurrently.

4. An object detector apparatus as claimed in claim 2, further comprising first circuitry configured to sample the signal into the first sampled data set, and second circuitry configured operate in parallel with the first processor to sample the signal into the second sampled data set.

5. An object detector apparatus as claimed in claim 4, in which the first processor is configured to compare the first sampled data set with the first previously sampled data set and produce an output signal indicative of whether an object has been detected based on the comparison, and in which the second processor is configured to compare the second sampled data set with the second previously sampled data set and to produce an output signal indicative of whether an object has been detected based on the comparison.

6. An object detector apparatus as claimed in claim 5, in which an object detected signal is output when either or both of the first and second processors output a signal indicative of an object being detected.

7. An object detector apparatus as claimed in claim 1, in which the signal sampled into the second sampled data set is a different signal to the signal that is sampled into the first data set.

8. An object detector apparatus as claimed in claim 7, in which the signal sampled into the second sampled data set is a signal received by the receiver subsequent to the signal that is sampled into the first data set.

9. An object detector apparatus as claimed in claim 8, further comprising circuitry which is configured to sample the signal into the first sampled data set and to subsequently sample the signal into the second sampled data set.

10. An object detector apparatus as claimed in claim 1, further comprising an input mechanism by which the sampling parameters used by the analyzer can be changed.

11. An object detector apparatus as claimed in claim 10, in which the input mechanism comprises a feedback device which is operable to determine the frequency of the repetitive motion of the object and to change the first and/or second sampling parameters used by the analyser based on the determined frequency of repetitive motion.

12. An object detector apparatus as claimed in claim 1, in which the analyser is operable to sample a signal received by the receiver using at least a third set of sampling parameters which differs to the first and second sets of sampling parameters into at least a third sampled data set, and to output an object detected signal based on a comparison of the third sampled data set with a previously sampled data set.

13. An object detector apparatus as claimed in claim 1, in which the sampling parameters comprise a sampling rate.

14. An object detector apparatus as claimed in claim 1, in which the sampling parameters comprise the number of previously sampled data sets the first and second sampled signals are compared with.

15. An object detector apparatus as claimed in claim 1, in which the sampled data sets comprise binary data.

16. An object detector apparatus as claimed in claim 1, in which the receiver is configured to receive an optical signal from an object.

17. An object detector apparatus as claimed in claim 1, further comprising a transmitter configured to transmit a signal, the signal received by the receiver being at least a partial reflection of the transmitted signal.

18. An object detector apparatus as claimed in claim 1 in which the object to be detected is a cutting tool.

19. An object detector apparatus as claimed in claim 1, in which the repetitive motion is rotational.

25. A machine tool apparatus incorporating an object detector apparatus as claimed in claim 1.

20. An object detector apparatus, comprising:

a receiver configured to receive a signal from an object having a repetitive motion, the signal repeating at a frequency that is dependent on the frequency of the repetitive motion of the object; and

an analyser coupled to the receiver, the analyser being configured to sample the signal according to a first set of sampling parameters into a first sampled data set, and to produce a first output signal based on a comparison of the first sampled data set with at least one previously sampled data set, and to concurrently sample the signal using a second set of sampling parameters which differs to the first set of sampling parameters into a second sampled data set, and to produce an second output signal based on a comparison of the second sampled data set with at least one previously sampled data set.

21. An object detector apparatus, comprising:

a receiver configured to receive a signal from an object having a repetitive motion, the signal repeating at a frequency that is dependent on the frequency of the repetitive motion of the object; and

an analyser coupled to the receiver, the analyser being configured to sample a first signal received by the receiver according to a first set of sampling parameters and to produce a first output signal based on a comparison of the first sampled data set with at least one previously sampled data set, and the analyser being configurable to subsequently sample a second signal received by the receiver subsequent to the first signal according to a second set of sampling parameters which differ to the first set of sampling parameters, and to produce an second output signal based on a comparison of the second sampled data set with at least one previously sampled data set.

22. An object detector apparatus, comprising:

a receiver configured to receive a signal from an object having a repetitive motion, the signal repeating at a frequency that is dependent on the frequency of the repetitive motion of the object;

an analyser coupled to the receiver, the analyser being configured to sample the signal according to a first set of sampling parameters into a first sampled data set, and to produce a first output signal based on a comparison of the first sampled data set with at least one previously sampled data set;

and

an input mechanism by which the first set of sampling parameters can be input to the analyser.

23. An object detector apparatus as claimed in claim 22, in which the input mechanism comprises a feedback device which is operable to determine the frequency of the repetitive motion of the object.

24. An object detector apparatus as claimed in claim 23, in which the input mechanism is configured to determine the first set of sampling parameters based on the determined frequency of the repetitive motion of the object.

26. A method of detecting the presence of an object, the method comprising:

(i) receiving a signal from an object having a repetitive motion, the signal repeating at a frequency that is dependent on the frequency of the repetitive motion of the object;

(ii) sampling the signal received according to a first set of sampling parameters into a first sampled data set, and producing an output signal based on a comparison of the first sampled data set with a first previously sampled data set; and

(iii) sampling the signal received according to a second set of sampling parameters which differ to the first set of sampling parameters into a second sampled data set, and producing an output signal based on a comparison of the second sampled data set with a second previously sampled data set.

27. A method as claimed in claim 26, in which the signal sampled into the first sampled data set is the same signal as the signal sampled into the second sampled data set.

28. A method as claimed in claim 27, in which the sampling of the received signal according to the second set of sampling parameters occurs substantially concurrently with the sampling of the received signal according to the first set of sampling parameters.

29. A method as claimed in claim 27, in which the signal sampled into the second sampled data set is a signal received by the receiver subsequent to the signal that is sampled into the first data set.

30. A method as claimed in claim 29, in which the method further comprises subsequent to step (i) and prior to step (ii), inputting the second set of sampling parameters and reconfiguring the analyser to use the second set of sampling parameters.