Distance Measuring Sensor and Method for the Detection and Distance Determination of Objects

• US 20150204978A1
• Filed: 01/09/2015
• Published: 07/23/2015
• Est. Priority Date: 01/22/2014
• Status: Active Grant

• Current Assignee: Sick AG (Sick)
• Original Assignee: Sick AG (Sick)
• Inventors: HAMMES, Markus, MUNCHER, Martin
• Granted Patent: US 9,798,003 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01S 13/10 using transmission of interrupted, pulse modulated waves determination of distance by phase measurement G01S13/32
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 7/2923 based on data belonging to a number of consecutive radar periods
• CPC Class Codes: G01S 7/4865 Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak peak detection in noise, signal conditioning G01S7/487
• CPC Class Codes: G01S 7/487 Extracting wanted echo signals , e.g. pulse detection

Abstract

A distance measuring sensor (10) for a detection and distance determination of objects (18) in a monitoring area, the sensor (10) having a transmitter (12) for transmitting transmission pulses, a receiver (20) for generating a reception signal from transmission pulses remitted from the monitoring area, an A/D converter (38) for digitizing the reception signal, and a control and evaluation unit (28, 30), which is configured to transmit a plurality of transmission pulses via the transmitter (12), to accumulate the respective reception signals generated by the receiver (20) in a histogram (110), and to determine, from the histogram (110), a reception point in time and thus a measurement value for the signal time of flight from the sensor (10) to the object (18), wherein the sensor (10) comprises a noise generator (40) configured to add a noise signal to the reception signal prior to its digitization in the A/D converter (38).

Claims

1. A distance measuring sensor (10) for a detection and distance determination of objects (18) in a monitoring area, the sensor (10) having a transmitter (12) for transmitting transmission pulses, a receiver (20) for generating a reception signal from transmission pulses remitted from the monitoring area, an A/D converter (38) for digitizing the reception signal, and a control and evaluation unit (28, 30), which is configured to transmit a plurality of transmission pulses via the transmitter (12), to accumulate the respective reception signals generated by the receiver (20) in a histogram (110), and to determine, from the histogram (110), a reception point in time and thus a measurement value for the signal time of flight from the sensor (10) to the object (18), wherein the sensor (10) comprises a noise generator (40) configured to add a noise signal to the reception signal prior to its digitization in the A/D converter (38).

2. The sensor (10) according to claim 1,

wherein the A/D converter (38) is a binarizer.

3. The sensor (10) according to claim 1,

wherein an analog preprocessing circuit (26) including a filter (30) for a conversion of a unipolar reception signal (102) into a bipolar signal (104) is arranged between receiver (20) and A/D converter (38).

4. The sensor (10) according to claim 1,

wherein the control and evaluation unit (30) is implemented on a digital module.

5. The sensor (10) according to claim 4,

wherein the digital module is a PLD, an ASIC, or an FPGA.

6. The sensor (10) according to claim 1,

wherein the noise generator is implemented as a digital unit.

7. The sensor (10) according to claim 4,

wherein the noise generator is implemented on the digital module (28).

8. The sensor (10) according to claim 1,

wherein the noise generator (30) generates a noise level adaptable by the control and evaluation unit (30) in order to set a reception sensitivity of the sensor (10).

9. The sensor (10) according to claim 1,

wherein the control and evaluation unit (30) is configured to set a suitable noise level of the noise generator (40) in advance.

10. The sensor (10) according to claim 1,

wherein the control and evaluation unit (30) is configured to take account of a natural noise signal when setting a noise level of the noise generator (40).

11. The sensor (10) according to claim 1,

wherein the control and evaluation unit (30) is configured to vary a noise level of the noise generator (40) during accumulation of a histogram (110).

12. The sensor (10) according to claim 1,

wherein the control and evaluation unit (30) is configured for a multi-channel recording and evaluation of histograms (110) in order to evaluate the reception signal with different sensitivities due to different noise levels of the noise generator (40) in the plurality of channels.

13. The sensor (10) according to claim 1,

the sensor (10) comprising a test signal generator (44) for injecting a test signal into the analog part of the receiving path in order to check the function of the receive path.

14. The sensor (10) according to claim 1,

the sensor (10) being configured as an optoelectronic sensor, wherein the transmitter (12) is a light transmitter and the receiver (20) is a light receiver.

15. The sensor (10) according to claim 14,

wherein the sensor (10) is a laser scanner.

16. A method for a detection and distance determination of objects (18) in a monitoring area, wherein a plurality of transmission pulses is transmitted and reception signals are generated from the transmission pulses remitted from the monitoring area, the reception signals are digitized and accumulated in a histogram (110) in order to determine, from the histogram (110), a reception point in time and thus a measuring value for the signal time of flight to the object (18), wherein a noise signal is added to the reception signal prior to its digitization.