DETECTION OF PEOPLE RELATIVE TO A PASSENGER CONVEYOR WITH A CAPACITIVE SENSOR

• US 20120247919A1
• Filed: 12/18/2009
• Published: 10/04/2012
• Est. Priority Date: 12/18/2009
• Status: Active Grant

• Current Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Original Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Inventors: Hsu, Arthur C., Veronesi, William A., Gschwendtner, Gero, Ercan, Abdullah, Senger, Alois, Soldner, Nicholas C., Siewert, Bryan R.
• Granted Patent: US 9,272,882 B2
• Time in Patent Office: Days
• US Class Current: 198/322
• CPC Class Codes: B66B 25/00 Control of escalators or moving walkways walkways of variable speed type B66B21/12; handrails of variable speed type B66B23/26; of general application G05
• CPC Class Codes: B66B 25/006 Monitoring for maintenance or repair for security reasons B66B29/005
• CPC Class Codes: G01R 15/16 using capacitive devices

Abstract

A system for detecting a person relative to a passenger conveyor includes a driving circuit for supplying an oscillating drive signal to a first electrode of a capacitive sensor configured to produce an electric field toward a second electrode in response to the oscillating drive signal. A detection circuit is connected to the capacitive sensor, and produces an output as a function of the capacitance of the capacitive sensor, such that the detection circuit senses a change in capacitance of the capacitive sensor, such as when a person enters the electric field between the first and second electrodes. A controller is responsive to the change in capacitance sensed by the detection circuit to selectively adjust an operation mode of the passenger conveyor.

Claims

1. A system for detecting a person relative to a passenger conveyer having a structural component and a passenger riding area, the system comprising:

a driving circuit for supplying an oscillating drive signal;

a capacitive sensor having a first electrode configured to produce an electric field toward a second electrode in response to the oscillating drive signal;

a detection circuit connected to the capacitive sensor that senses a change in capacitance of the capacitive sensor and produces an output as a function of capacitance; and

a controller responsive to the detection circuit output to selectively adjust an operation mode of the passenger conveyor.

2. The system of claim 1, wherein the first and second electrodes are disposed on portions of the passenger conveyor structural component on opposite sides of the passenger riding area, and wherein a change in capacitance is caused by the presence of a person in the electric field between the first and second electrodes.

3. The system of claim 1, wherein the first electrode comprises a conducting material disposed on the passenger conveyor structural component on a first side of the passenger riding area, and the second electrode comprises a conducting material disposed on the passenger conveyor structural component on a second side of the passenger riding area opposite the first side.

4. The system of claim 1, wherein the passenger conveyor structural component is a balustrade, and the first electrode comprises a conducting surface of the balustrade on one side of the passenger riding area, and the second electrode comprises a conducting surface of the balustrade on the opposite side of the passenger riding area.

5. The system of claim 4, wherein the balustrade is formed from a non-conducting material and a conductive material is disposed on a surface thereof on opposite sides of the passenger riding area.

6. The system of claim 5, wherein the non-conducting material is glass.

7. The system of claim 5, wherein the conductive material is adhered to the surface of the non-conducting balustrade.

8. The system of claim 5, wherein the conductive material is formed integrally with the non-conducting balustrade.

9. The system of claim 5, wherein the conductive material is divided into multiple sections.

10. The system of claim 9, wherein a multiplexer connects the sections to transmit the output of the capacitive sensor to the detection circuit.

11. The system of claim 1, wherein the first electrode comprises a sense wire located in a machine room of the passenger conveyor and the second electrode comprises a grounded component within the machine room.

12. The system of claim 1, the driving circuit further comprising:

an oscillator for creating an oscillating drive signal;

an amplifier connected to the oscillator to amplify the oscillating drive signal;

an impedance matching network connected between the amplifier and the capacitive sensor; and

a mode selector operable to drive the capacitive sensor in a selected mode.

13. The system of claim 12, wherein the oscillator has a frequency of 100 kHz to 1 MHz.

14. The system of claim 12, wherein the oscillator has a frequency of 100 kHz to 150 kHz.

15. The system of claim 1, wherein the detection circuit comprises:

a comparator configured to sense the change in capacitance of the capacitive sensor and produce the output as a function of capacitance of the capacitive sensor.

16. A method of detecting a passenger between first and second balustrades of a passenger conveyor, the method comprising:

supplying an electrical signal to a first electrode on the first balustrade to generate an electric field between the first electrode and the second electrode on the second balustrade opposite the first balustrade;

detecting a change in capacitance between the first and second electrodes; and

controlling operation of the passenger conveyor as a function of the detected change in capacitance.

17. The method of claim 16, wherein a change in capacitance is caused by the presence of a person in the electric field between the first and second electrodes.

18. The method of claim 16, wherein the first electrode comprises a conducting material disposed a surface of the first balustrade, and the second electrode comprises a conducting material disposed on a surface of the second balustrade.

19. The method of claim 16, wherein the electrical signal is a low-power oscillating drive signal.

20. The method of claim 16, wherein the electrical signal has a frequency of 100 kHz to 1 MHz.

21. A method of detecting a person in a machine room of a passenger conveyor, the method comprising:

transmitting an electrical signal to a sense wire located in the machine room to create an electric field between the wire and an electrically conductive component within the machine room that is electrically isolated from the sense wire;

detecting a change in capacitance between the sense wire and the electrically conductive component; and

controlling operation of the passenger conveyor as a function of the detected change in capacitance.

22. The method of claim 21, wherein a change in capacitance is caused by the presence of a person in the electric field between the sense wire and the electrically conductive component.

23. The method of claim 21, wherein the electrical signal is a low-power oscillating drive signal.

24. The method of claim 21, wherein the electrical signal has a frequency of 100 kHz to 1 MHz.