Method and system for detecting objects in a detection zone using modulated means

• US 6,279,687 B1
• Filed: 10/01/1999
• Issued: 08/28/2001
• Est. Priority Date: 10/01/1999
• Status: Expired due to Term

• Current Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Original Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Inventors: Pustelniak, Richard D., Morton, Teril W.
• Primary Examiner(s): SALATA, ANTHONY J
• Application Number:
  US09/410,561
• Time in Patent Office: 697 Days
• Field of Search: 187/316, 187/317, 187/291, 187/354, 49/25, 49/26, 49/28, 250/221, 250/222.1, 250/214.AL, 250/214.B, 250/208.3, 250/553
• US Class Current: 187/317
• CPC Class Codes: B66B 13/26 between closing doors
• CPC Class Codes: E05F 15/43 responsive to disruption of energy beams, e.g. light or sound
• CPC Class Codes: E05F 2015/434 with cameras or optical sensors
• CPC Class Codes: E05Y 2900/104 for elevators
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target

Abstract

A system and an associated method of detecting an object in a three-dimensional field adjacent to a doorway, such as an elevator doorway, uses an array of energy emitters that emit three-dimensional energy signals into the field and an array of energy receivers that receive the energy signals reflected from the object. The signals are sampled a predetermined number of times. In one embodiment, if the lowest value sampled signal reaches a predetermined threshold, an object detection signal is generated. In an alternative embodiment, if the sampled signals are within a predetermined variance range, the object detection signal is generated. In another alternative embodiment, if a predetermined modulation code is detected within a sampled signal, the object detection signal is generated.

Claims

1. A method of detecting an object in a zone of detection using a plurality of pairs of three dimensional energy emitters and receivers, wherein the emitters emit energy beams in a predetermined angle at the object and the receivers sense the energy beams reflected from the object, the method comprising:

sampling a reflected energy beam of an emitter receiver pair a predetermined number of times to provide a set of strength signals indicative of the strength of the reflected energy;

comparing the lowest value strength signal of the set of strength signals to a predetermined threshold value; and

generating an object detection signal when the lowest value strength signal reaches the predetermined threshold value.

2. The method of claim 1 further comprising:

determining a variance range for the set of strength signals;

comparing the variance range for the set to a predetermined maximum variance range; and

generating the object detection signal when the variance range is within the predetermined maximum variance range.

3. The method of claim 1 further comprising:

modulating an emitted energy beam of the emitter receiver pair with a predetermined modulation code;

detecting presence of the modulation code within the sampled energy beam; and

generating the object detection signal when the modulation code is detected.

4. The method of claim 2 further comprising:

modulating an emitted energy beam of the emitter receiver pair with a predetermined modulation code;

detecting the presence of the modulation code within the sampled energy beam; and

generating the object detection signal when the modulation code is detected.

5. The method of claim 1 wherein the sampling further comprises:

sampling the reflected energy beam to provide a resultant signal;

integrating the resultant signal for a predetermined period of time to provide an integrator output signal;

comparing the integrator output signal to a predetermined minimum detectable threshold value; and

generating an end of integration signal when the minimum detectable threshold value is reached.

6. The method of claim 1 further comprising:

providing a plurality of pairs of curtain energy emitters and receivers, wherein the emitters emit a curtain of energy beams directly at each corresponding receiver;

sampling a directly emitted energy beam of a curtain emitter receiver pair to provide a curtain signal indicative of the absence of an object within the curtain; and

generating a second object detection signal when the curtain signal is interrupted.

7. The method of claim 1 wherein the emitter receiver pair further comprises every emitter receiver pair of the plurality of pairs of energy emitters and receivers.

8. The method of claim 1 wherein the plurality of pairs of three dimensional energy emitters and receivers are mounted on opposing doors of an elevator car.

9. The method of claim 3 wherein the modulation code comprises a binary code.

10. A system for detecting an object in a zone of detection comprising:

a plurality of pairs of three dimensional energy emitters and receivers, wherein the emitters emit energy beams in a predetermined angle at the object and the receivers sense the energy beams reflected from the object;

a controller responsive to signals from the receivers, the controller having data acquisition and data processing circuitry for,

sampling a reflected energy beam of an emitter receiver pair a predetermined number of times to provide a set of strength signals indicative of the strength of the reflected energy;

comparing the lowest value strength signal of the set of strength signals to a predetermined threshold value; and

generating an object detection signal when the lowest value strength signal reaches the predetermined threshold value.

11. The system of claim 10, wherein the data acquisition and data processing circuitry further comprises circuitry for:

determining a variance range for the set of strength signals;

comparing the variance range for the set to a predetermined maximum variance range; and

generating the object detection signal when the variance range is within the predetermined maximum variance range.

12. The system of claim 10, wherein the data acquisition and data processing circuitry further comprises circuitry for:

modulating an emitted energy beam of the emitter receiver pair with a predetermined modulation code;

detecting presence of the modulation code within the sampled energy beam; and

generating the object detection signal when the modulation code is detected.

13. The system of claim 11, wherein the data acquisition and data processing circuitry further comprises circuitry for:

modulating an emitted energy beam of the emitter receiver pair with a predetermined modulation code;

detecting presence of the modulation code within the sampled energy beam; and

generating the object detection signal when the modulation code is detected.

14. The system of claim 10 wherein the plurality of pairs of three dimensional energy emitters and receivers are mounted on opposing doors of an elevator car.

15. The system of claim 10 wherein the data acquisition and data processing circuitry further comprises a microprocessor responsive to the signals from the receiver, and having memory for storing signals including signals for defining an executable program for generating the object detection signal.