JP2006512568A - Position reference system - Google Patents

Abstract

The present invention relates to a position reference system for a horizontal or vertical transporter, for example an elevator. The position reference system illuminates one of the reflectors with a plurality of spaced apart color elements or reflectors (42) attached to a stationary structure (40) such as a hoistway or taxiway door frame. A light source (12) and a detection device (10, 48, 48 ′) for acquiring an image of the irradiated reflector. The image acquired by the sensing device is used to determine the position and / or speed of a transporter such as an elevator car.

Description

  The present invention relates to an inexpensive and high performance absolute position reference system and method for other (passenger) vehicles such as elevators and horizontal passenger vehicles.

  A position reference system is a component of a control system that provides quick and accurate position measurement of an elevator car in a hoistway or a (passenger) room on a taxiway. The speed and accuracy of the position reference system is determined by a given control system to ensure a certain level of ride comfort. As an example, the position measurement must be performed with a delay within 10 ms and with an accuracy within 1 mm. These performance requirements are very demanding considering the wide operating range of the elevator (up to 500 m) and the long distance between the (passenger) transport stops. In addition to the performance requirements for accuracy and measurement delay, minimizing corrective operation performed, for example, at power-on is another important performance requirement. In this context, “minimize” means within one floor, or within one stop in distance.

  In the following description, the term elevator is used to denote a horizontal or vertical (passenger) transporter without prejudice.

  Many existing position reference systems for elevators are based on encoders attached to drive motors, governors, or independent pulleys. The problem with such a position reference system is the error between the encoder reading and the actual position caused by slipping, rope stretching, sub-system mechanical wear, and / or building shaking. In order to minimize this error, frequent corrections need to be made based on several fixed known reference points that indicate the actual location of the stop and leveling zones. A vane system consisting of a vane reader and vane provides these reference points and their detection means. Given the simple function of the vane system, the vane system is very cost-effective. This is because the vane installed in the hoistway by the machinist requires $ 10 for materials, 0.5 hours for installation, and 0.1 hours for adjustment for each floor. In summary, one of the most serious problems with existing location reference systems is the low performance to cost ratio.

  Accordingly, it is an object of the present invention to provide a position reference system and method that is accurate, requires minimal corrective operation, and is easy to install and maintain.

  Another object of the present invention is to provide a position reference system and method as described above that is free of installation work on hoistways or taxiways.

  The above objective is accomplished by a position reference system and method of the present invention.

  The position reference system according to the present invention is generally detected by a plurality of spaced color elements attached to a fixed structure and means attached to the movable structure for detecting one of the spaced color elements. Means for determining the position of the movable structure from the obtained color elements. As used herein, the term “color” means not only visible colors, but also invisible colors in the electromagnetic spectrum, such as ultraviolet, infrared, radio frequency, and microwave. As used herein, the term “movable structure” may be an elevator car or a horizontal passenger carrier.

  The position reference method according to the present invention generally includes attaching a plurality of spaced color elements to a fixed structure, detecting one of the spaced color elements, and a movable structure from the detected color elements. And determining the position of.

  Other details of the position reference system and method according to the present invention, as well as other objects and advantages associated therewith, will be described in the following detailed description and attached drawings. Note that similar reference symbols in the drawings represent similar elements.

  Referring to the drawings, FIG. 1 illustrates the operation of a relative positioning system based on a one-dimensional charge coupled device (CCD) 10. That is, the reflector 11 is irradiated by the light source, that is, the linear radiation light source 12. Light is reflected by the reflector 11 to produce an optical image 13. A camera 10 which is preferably a CCD detection device detects at least a part of the optical image 13 and converts the detected image into an electrical signal. This electrical signal is transmitted to a processing device 14 such as a computer programmed in advance and stored in a memory 16 attached to the processing device 14. The position of the center 18 of the reflector 11 relative to the center 19 of the CCD device 10 can be calculated using a signal processing algorithm programmed in the processing device 14. Signal processing algorithms include sub-pixel resolution signal processing algorithms and may thus include any suitable algorithm known for calculating relative distances. The CCD camera 10 preferably has a CCD sensor, a lens, and a light guide.

The CCD device 10 is preferably a color CCD detection device. The color image thus detected by the color CCD 10 such as a color camera may be separated into the three primary colors, namely red, green and blue, as shown in FIG. Current color CCDs have a 12-bit color depth for each of these three colors. This means that a color CCD can ideally distinguish 236 colors. This ideally means that 236-bit information can be encoded by using colors that can be decoded using the color CCD sensor 10. One of the three primary colors can be used for positioning, and this color may be called a positioning color. The intensity of the positioning color in the CCD image of each reflector is the same as each other, for example 100%, in the sense that all reflectors are colored with respect to the positioning color under a given light source. The positioning mechanism in this case is exactly the same as that shown in FIG. The other two primary colors may be referred to as encoding colors, and the combination of these two colors includes some specific position information after being normalized with respect to the positioning color. For example, suppose that blue is a positioning color and red and green are encoding colors. In a building up to 500 m, 500 different colors are sufficient as position information (considering that the normal CCD device 10 has a detection range of 1.3 m). Thus, it is sufficient that there are 25 different color depths for each encoded color. As shown in FIG. 2, it is assumed that R, G, and B are color intensity outputs of color CCDs representing red, green, and blue, respectively. Also, RB and GB are defined as follows:
RB = [25 × R / B], GB = [25 × G / B]
Here, [a] is equal to the largest integer smaller than a, and the intensity of the positioning color is 100%. In addition, since additional illumination such as non-uniform illumination intensity or sunlight changes the R, G, and B of the reflector at the same rate, the normalization process shown in the above equation is desirable. The normalization process described here eliminates the possibility of decoding errors due to strength variations.

  The decoding table is as follows.

That is, if RB and GB are 1 and 24, respectively, it can be seen that the decoded number is 50 from Table 1. From the decoded number, the particular color element of the illuminated reflector 42 is determined and the position of the CCD device 10 and the elevator car to which it is attached is calculated. When using this method, the color of the reflector is selected to ensure that its position information decoded is the same under expected variations in the intensity of the light source.

  If it is too expensive to use 500 different color reflectors, different color columns can be used to encode the position information. For example, four columns of reflectors of six different colors can contain 500 different conditions of position information.

  3A and 3B, the configuration and operating mechanism of the position reference system 30 of the present invention is illustrated. In the system 30, a plurality of spaced reflectors or color elements 42 are attached to a stationary structure such as a door frame 40 or wall in a hoistway 41. A CCD assembly 32 including a CCD sensor box 48 is preferably attached to the frame 34 on the side of the elevator car, but may be attached to any other location, such as the bottom of the car. One or more light sources 12 are provided on the frame 34 to illuminate the reflector 42 in the vicinity of the car.

  In operation, light from the light source (s) 12 illuminates the reflector 42 near the car. The light reflected by the reflector 42 is detected by the CCD sensor box 48 where it is converted into electrical signals representing the three primary colors, red, blue and green. The electrical signal is transmitted to a preprogrammed processor 14 to determine the position of the elevator car. As described above, one of the three primary colors, ie, red, blue, and green, is selected as the positioning color. The signals representing the remaining primary colors are normalized as described above. From the normalized signal and a decoding table stored in a memory associated with the processing unit 14, a decoded number for the detected reflector or color element 42 is determined. The detected reflector or color element 42 is identified by the decoded number. Using this information and its position in the field of view of the CCD sensor box 48, the position of the elevator car is determined.

  If desired, the CCD sensor box 48 may be used to detect the upper and lower ends of the reflector 42 within its field of view. Using the electrical signals representing the positions of the upper and lower ends in the field of view of the CCD sensor box 48, the precise position of the elevator car is determined.

  Next, referring to FIG. 3B, a configuration devised to solve two problems is shown. One problem is interference from ambient light. In this configuration, a sealed light guide 20 is used to solve this problem. Further, in a transparent hoistway, each light source 12 may be a linear light source that is polarized. In addition, the sealed light guide 20 may include a polarizing window 22 if necessary. By providing the polarized linear light source (s) 12 and the polarization window 22, the signal-to-noise ratio is improved with respect to the interference of ambient light.

  Another problem that this configuration solves is haze. The linear light source 12 and the sealed light guide 20 provide a sufficiently clear image even under a lot of smoke. This is because the use of the linear light source 12 and the sealed light guide 20 minimizes the light path in the fumes. Desirably, the distance between the reflector 42 and the CCD assembly 32 may be less than 3.0 cm.

  In order to achieve a constant intensity reflector image regardless of the position of reflector 42 relative to the position of CCD assembly 32, linear light source 12 can have a non-uniform spatial intensity profile. For example, the illumination intensity of the light source 12 may be highest at both ends of the light source and lowest at the center of the light source.

  FIG. 4 shows the operation and configuration of a position reference system based on a CIC CCD. As shown in this figure, the door frame 40 is provided with a plurality of color reflectors 42. A CCD assembly 32 having an upper CCD detector 48 and a lower CCD detector 48 ′ is attached to a frame 34 attached to the elevator car 35. At least one light source 12 is associated with each of the upper and lower detectors 48 and 48 '.

  When the configuration of FIG. 4 is used, the following functions are achieved. Normal position feedback to the control system is achieved, assuming that the distance between any two adjacent floors is within the height of the car plus 1.3m, except for the two floors at both ends of the express zone Is done. Two CCD sensors 48 and 48 'provide velocity measurements as well as accurate position measurements at any point in the hoistway. In the express zone, there are a few reflectors at each end of the express zone. As a result, the position reference system of the present invention provides accurate positioning until the express zone begins and immediately after the express zone ends. Since there is no stop floor in the express zone, positioning in the express zone is performed by open loop control. The same method may be used for long floor distances such as hotel lobbies.

  By installing a reflector every 1.3 m in the area of the normal end stop (NTSD) and emergency end stop / emergency end point speed limiter (ETSD / ETSLD), each CCD assembly 48 and 48 'is independently Gives speed and position measurement information. One is for NTSD and the other is for ETSD / ETSLD.

  The system shown in FIG. 4 is also capable of minimizing corrective operation. Except for the two floors at both ends of the express zone, assuming that the distance between any two adjacent floors is within the height of the car plus 1.3 meters, the ability to eliminate any corrective operation is achieved. The Within the express zone, long reflectors covering the upper and lower halves of the express zone may be attached, and normal reflectors may be attached at normal inter-story spacing. Based on the presence of the reflector, the elevator car can determine at least where the floor closest to the car is. Determining which direction to move up and down is the only function required when power is restored. It should be noted that it is easy to attach long tapes or individual CIC reflectors to the hoistway. As an alternative, the elevator may slowly move up or down after power is restored until it reaches the floor. Even in this case, corrective operation is within the first floor.

  The location reference system and method of the present invention provides many advantages. That is, (1) high accuracy in any place of the hoistway or taxiway, (2) high position update speed, (3) low installation cost, with little or no construction on the hoistway or taxiway No, (4) Simple structure, no mechanical wear, low maintenance cost due to easy maintenance, (5) Low management cost because it can be applied comprehensively, (6) Minimizing corrective operation .

  Although the position reference system of the present invention has been described with reference to an elevator position reference system, the same system can also be used to determine the position of a horizontal passenger transport system. In such a system, the fixed structure is a door frame of a transportation taxiway and the movable structure is a device or passenger cabin for carrying a person substantially horizontally or at an angle to a horizontal axis. One or more light sources and detection devices may be attached to the movable structure.

  Although the position reference system of the present invention has been described with reference to a sensing device 10 for detecting red, green, and blue, the sensing device may also detect invisible light having a unique wavelength in the electromagnetic spectrum. Invisible light includes, but is not limited to, ultraviolet, infrared, radio frequency, and microwave. In this regard, each color element 42 may reflect a unique wavelength of electromagnetic waves.

  Obviously, the present invention provides a position reference system that fully satisfies the aforementioned objects, means, and advantages. Although the present invention has been described with reference to specific embodiments thereof, other alternatives, improvements, and modifications will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the appended claims is intended to cover these alternatives, modifications, and variations.

FIG. 1 is a conceptual diagram of a positioning system based on a charge coupled device (CCD). FIG. 2 is a conceptual diagram of red, green, and blue (RGB) decomposition of a color CCD image. 3A and 3B are conceptual diagrams of a position reference system according to the present invention. FIG. 4 is a conceptual diagram of a position reference system based on a color (CiC) CCD.

Claims (23)

Multiple spaced color elements attached to a fixed structure;
Means attached to the movable structure for detecting one of the spaced apart color elements;
Means for determining a position of the movable structure from the detected color elements;
A position reference system comprising:   The position reference system according to claim 1, wherein the fixed structure is an elevator hoistway and the movable structure is an elevator car.   3. The detection means includes at least one camera for determining a color of the detected color element and detecting an upper end portion and a lower end portion of the detected color element. The location reference system described.   4. The position reference system according to claim 3, wherein each of the color elements reflects a unique wavelength of the electromagnetic spectrum.   The at least one camera is attached to a side surface of the elevator car, the fixing structure is a door frame in the hoistway, and the plurality of spaced color elements are attached to the door frame. 4. The position reference system according to claim 3, comprising colored elements.   The detection means detects a plurality of unique color components of the detected color element, the determination means selects one of the plurality of unique color components as a positioning color, and the plurality of unique colors Normalizing the rest of the components with respect to the positioning color, determining a decoded number of color elements detected from the normalized one of the plurality of unique color components, and detecting the detected number from the decoded number 4. The position reference system according to claim 3, wherein a color element is identified.   4. The position reference system according to claim 3, wherein the detection means further comprises a linear radiation source for irradiating the detected one of the color elements, and a camera device.   8. The position reference system according to claim 7, wherein the camera device includes a CCD camera.   9. The position reference system according to claim 8, wherein the CCD camera comprises a CCD sensor, a lens, and a light guide.   The detection means includes a first camera device attached to a first part of the elevator car, and a second camera device attached to a second part of the elevator car, the first and first 4. A position reference system according to claim 3, wherein the two camera devices operate independently to provide overlapping speed and position information.   The position reference system according to claim 1, wherein the fixed structure is a transportation guideway, and the movable structure is a passenger cabin.   12. The detection unit includes at least one camera for determining a color of the detected color element and detecting an upper end portion and a lower end portion of the detected color element. The location reference system described.   The position reference system according to claim 12, wherein the color element reflects a unique wavelength of an electromagnetic spectrum.   The at least one camera is attached to a side surface of the passenger cabin, the fixing structure is a door frame in the transportation guideway, and the plurality of spaced color elements are attached to the door frame. 13. The position reference system according to claim 12, comprising elements having different colors.   The detection means detects a plurality of unique color components of the detected color element, the determination means selects one of the plurality of unique color components as a positioning color, and the plurality of unique colors Normalizing the rest of the components with respect to the positioning color, determining a decoded number of color elements detected from the normalized one of the plurality of unique color components, and detecting the detected number from the decoded number 13. The position reference system according to claim 12, wherein a color element is identified.   13. The position reference system according to claim 12, wherein the detecting means further includes a linear radiation source for illuminating the detected one of the color elements, and a camera device.   The position reference system for passenger transportation according to claim 16, wherein the camera device comprises a CCD camera.   18. The position reference system for passenger transportation according to claim 17, wherein the CCD camera comprises a CCD sensor, a lens, and a light guide.   The detection means includes a first camera device attached to a first portion of the passenger cabin, and a second camera device attached to a second portion of the passenger cabin, the first and first 13. The position reference system for passenger transportation according to claim 12, wherein the two camera devices operate independently to provide overlapping speed and position information. A method for determining the position of a movable structure,
Attaching a plurality of spaced color elements to a fixed structure;
Detecting one of the spaced color elements using a sensing device attached to the movable structure;
Determining the position of the movable structure from the detected color elements;
A method for determining the position of a movable structure comprising:   21. The method of claim 20, wherein the detecting step comprises illuminating the color element with a radiant light source and acquiring a reflected image with a sensing device.   The detecting step comprises obtaining a reflected color light image including a plurality of primary colors, and the determining step selects one of the primary colors as a positioning color and the remaining colors with respect to the positioning color. 21. A method according to claim 20, comprising normalizing.   Determining the position comprises determining a decoded number of the color element, identifying the color element from the decoded number, and thus determining the position of the movable structure. The method of claim 22.

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