JPS6022282B2 - Position measurement method for moving objects - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a measuring device suitable for measuring the position and orientation of a moving body in a two-dimensional space such as a factory, building, shipbuilding site, etc.

Conventionally, in order to measure a position in a wide space, it is common to construct a large framework and measure scales attached to it, or simply to measure using a tape measure or transit. However, the former requires special equipment to perform measurements, which lacks flexibility and poor workability, while the latter not only has poor work efficiency but also requires a special device to measure the path of the moving object. It is not suitable for The method of the present invention enables the position and orientation of a moving object to be measured by detecting the directions of three strip light sources on the traveling plane of the moving object using a simple measuring device on the moving object. When using a television camera to measure the position of a moving object based on the principle of triangulation, a vertical window is set in the television screen,
A slit detection signal is output when the image of a slit light source installed vertically on the traveling plane of the moving body is within its window, and the slit light source is output based on the rotation angle of the television camera when this slit detection signal is output. The feature is that simple and accurate measurement is possible by measuring the direction of.

0 Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 is a plan view schematically showing the measurement principle of the present invention.
It shows the state in which the Y coordinate is set, and then it turns off.

In the present invention, slit light sources A, B, and C are set up at three reference points around this two-dimensional space, and in FIG. (0,
0), (b, 0). Note that the arrangement of this slit light source is optimally selected in consideration of the moving area of the moving body and measurement accuracy. Each of the slit light sources A, B, and C is designed to emit light through narrow vertical slits in order to improve position measurement accuracy and to prevent other environmental objects from being mistaken for slit light sources. It is constructed by arranging a slit along the longitudinal direction just in front of the fluorescent lamp, and two of these slit light sources A and C are single slit light sources with a single slit, but one slit light source B For example, use this as a double slit light source with two vertical slits in close proximity. Make it distinguishable from a single slit light source.

Additionally, double slit light sources and triple slit light sources can also be used to ensure prevention of misidentification. on the other hand,
The movable body 1 that travels in the two-dimensional space is configured as an automatically traveling trolley loaded with, for example, machinery, and this movable body includes a television camera 2 that detects the slit light source and a detection circuit for the slit light source. and a measuring device (see Fig. 3) equipped with a rotation angle detection circuit, and this measuring device measures the angle between each slit light source A, B, and C as seen from the moving body 1, and the angle between these slit light sources and the moving body. By measuring the angular relationship between the moving body 1 and the reference line 1, the position (x, y) of the moving body 1 in the two-dimensional space and its direction are measured.

The above-mentioned television camera, slit light source detection circuit, and rotation angle detection circuit are configured such that one set of them is provided on a moving body as described below, and the direction of each slit light source is sequentially detected by rotating the field of view of the television camera. Yes, but part 3 is on a moving object.
It is also possible to provide sets for each slit light source A, B, and C, with each television camera tracking a separate slit light source.

As shown in FIG. 2, the television camera 2 has its pupil directed upward, and a veriscope 3 equipped with an oblique mirror 4 and a doped prism 5 is rotated around the optical axis by a pulse motor 6 or the like. Alternatively, the optical pulp can be directed horizontally and the television camera itself can be rotated around a vertical axis by a pulse motor or the like, and the rotation angle of the television camera 2 etc. is as follows when the pulse motor is used:
It can be measured by the number of driving pulses.

Further, a synchro motor or the like may be used instead of this pulse motor, and in this case, the rotation angle will be measured by an encoder. When the needle 7 provided on the veritascope 3 or television camera 2 rotates together with the veriscope and passes through the photointerrupter 8 provided on the moving object, the needle 7 transmits light from the light emitting element in the photointerrupter 8 to the light receiving element. Something that interrupts and generates a pulse output 0
Then, the direction of the moving object 1 is measured using the direction of the television camera 2 on the moving object at the time of this pulse output as the direction of the reference line 1. Position measurement in the present invention is XY coordinate measurement when the moving body 1 is stationary (hereinafter referred to as stationary mode).

), and successive measurements of the relative angle between the direction of the slit light source and the direction of the reference line 1 on the moving object (hereinafter referred to as the moving mode) when the moving object is moving. The system allows the body to confirm its own position in a stationary state, and then automatically moves along a pre-given route. FIG. 3 shows a circuit configuration of a measuring device that performs measurements in the stationary mode and moving mode, and based on this, the measuring method in the stationary mode and moving mode will be described in detail below. As mentioned above, it is possible to use only one set of the television camera and measuring device, or to use three sets thereof, but in these cases, measurements can be performed using substantially the same circuit configuration. Therefore, the case where only one set of the television camera and the measurement equipment layer 0 is used will be explained here together with the circuit configuration of FIG. 3, and then the case where three sets are used will be additionally described.

First, in the stationary mode, one television camera is rotated at a constant speed in the direction of rotation by a drive motor such as the above-mentioned pulse motor, and the video signal that is the output of the television camera is adjusted to an appropriate threshold value in an analog circuit. By comparison, it is converted into a rectangular wave luminance signal having outputs corresponding to the slit light sources A, B, and C.

Note that the analog circuit is provided with an adjustment knob for setting the threshold value to an optimal value. The window gate circuit to which the vertical and horizontal synchronization signals from the analog circuit are applied sets a vertically elongated window 10 on the television screen 9 and opens the gate circuit corresponding to this window 10, as shown in FIG. This outputs a window signal, and specifically, the circuit configuration can be as shown in FIG. 5.

The wind gate circuit shown in Fig. 5 is divided into 8 scanning lines from the 128th scanning line in the vertical direction and 25 in the horizontal direction, as shown in Fig. 4. This shows a case where the window 10 is set.

In this circuit, a D flip-flop (1) is set by a vertical synchronization signal, the number of horizontal synchronization signals is counted in a counter (N), and when the count reaches 128, the gate input signal (1) from the counter becomes a logic 1
Then, when 8 counts have been made, that is, when the horizontal synchronizing signal of the 136th scanning line has been counted, the D flip-flop (1) and the counter (1) are reset.
Note that the D flip-flop is a type of flip-flop in which data at the D input is set at the falling edge of the Ck input. On the other hand, the D flip-flop (0) is set by the horizontal synchronizing signal, and the counter (V) counts the number of clocks from the oscillator with a period that divides one scanning line into 25 pieces. Due to counting, the gate input signal (0) from the counter (V) becomes logic 1, and at the next clock, the D flip-flop (0) and the counter (
V) is reset and the gate input signal (b) becomes logic 0.

When this gate input signal (n) and the gate input signal (1) are both logic 1, the window signal is logic 1.
is output as In this wind gate circuit, by changing the count value in the counter (V), a narrow single-slit window signal is generated for the luminance signal of the single-slit light source, and a slightly wider double-width signal is generated for the luminance signal of the double-slit light source. A slot window signal is output.

The rectangular wave luminance signal output from the analog circuit in FIG. 3 is applied to a slit center detection circuit, and this detection circuit detects the center of the rectangular wave having a certain width.

This slit center detection circuit is intended to improve measurement accuracy, and is not necessary if the width of the rectangular wave is sufficiently narrow relative to the slit light source. Good. The above slit center detection circuit detects the center of a rectangular wave by using a counter that counts pulses from an oscillation circuit and pulses having twice the frequency of the oscillation circuit, and detects the center of the rectangular wave. A pulse is output.This pulse is added to the AND gate (1) which is opened by the single slit window signal, and when the center of the slit light source is within the single slit window, the slit light source is detected. The above pulse is sent to the counter (1) through the band gate (1).The counter (1) and the comparator circuit (1) connected to it constitute a majority circuit, and the majority of the scanning lines included in the window When there is a pulse output from the slit center detection circuit, that is, when pulses are continuously sent from the AND gate (1), it is detected in the comparator circuit (1), and the comparator circuit (1) It is assumed that the single slit light source is finally detected by the output single slit detection signal.In addition, in order to detect the double slit light source, the above luminance signal output from the analog circuit is used as the above double slit window signal. It is assumed that a double slit light source is detected by the output of the comparator circuit (0) in the same manner as in the case of a single slit.

Furthermore, since this double slit light source is also detected as a single slit light source, the first output from the comparison circuit (1) for the two slit light sources in the double slit light source (if the TV camera is rotating clockwise) A double slit detection signal is obtained by ANDing the output for the left slit light source) with the output of the comparator circuit (0), and once the double slit light source is detected, the double slit light source is completely detected. Detection is prohibited for a certain period of time until the device moves out of the window to prevent the double slit light source from being detected as a single slit light source. The single slit detection signal and double slit detection signal are output in synchronization with the vertical synchronization signal,
They are stored in flip-flop (1) and flip-flop (0), respectively, and then counter (1) and counter (0) are reset by the vertical synchronization signal.

In detecting such a slit light source, the above-mentioned slit center detection circuit is provided, the detection circuit generates a pulse corresponding to the center of the slit light source, the width of the window 10 is made as small as possible, and the width of the window 10 is made as small as possible. By using a telephoto lens for the television camera, it is possible to improve the accuracy of measurement of the point in time when the rotating television camera detects the slit light source, that is, the accuracy of angle detection.

The motor pulse gate circuit outputs the photointerrupter,
The AND gates (m) and (N) are controlled based on the single slit detection signal and double slit detection signal, and the drive pulses are distributed to the pulse motor as the drive motor, and the pulses are input to the up/down counter. In the stationary mode, only the AND gate (m) is opened and a drive pulse from the oscillation circuit is sent to the drive motor, causing the drive motor to rotate at a constant speed in one direction as described above. Further, the up/down counter is controlled directly by the output of the photointerrupter, the single slit detection signal and the double slit detection signal, or via a motor pulse gate circuit, but in this static mode, the double slit light source Since the angle measurement starts from the moment when is detected, the up/down counter is reset by the double slit detection signal to start counting, and the contents of the counter are transferred to the computer by the output of the photointerrupter and the single slit detection signal. When the fourth slit light source is detected, that is, when the double slit light source is detected again, the cursor is stopped, the data transfer and reset are performed, and the drive motor is stopped at the same time.

The counter (m) is reset by the double slit detection signal, the single slit detection signal and the photointerrough.

The flip-flop (m) is set by the output of the photointerrupter and reset by the single slit detection signal. data and whether it is the output of the photo interrupter or not, and these are transferred to the computer together with the contents of the up/down counter.
Then, the computer calculates the angles a, to a4 in FIG. 1 using the number of pulses given as the count data of the up-down counter, and further calculates the coordinates of the current position of the moving object 1 based on the principle of angle measurement. In addition to calculating x and y, the direction cosine of the direction of the moving object is calculated and displayed as appropriate.

After measuring the coordinates and orientation of the moving object in the stationary mode in this manner, the moving object is automatically moved along a predetermined route in the moving mode.

In this movement mode, detection of the double slit light source is prohibited and only the single slit detection signal output from the comparison circuit (1) is used, and the width of the single slit window 10 set by the wind gate circuit is As shown in the television screen 9 in FIG. 6, it is assumed that the image spreads from the center to one side.

At the end of the stationary mode, as is clear from the foregoing, the television camera will be pointing at the dual slit light source, so that the image of the dual slit light source will be approximately in the center of the television screen in FIG. In the movement mode,
The double-slit light source is tracked by the single-slit detection signal from the comparison circuit (1), and the moving object is tracked using the contents of the up-down counter as the increment/decrement of the angle of the moving object with respect to the direction of the double-slit light source. Let it run. That is, when the image of the slit light source is within the window 10 and a single slit detection signal is output, the motor pulse gate circuit operates the drive motor so that the image of the slit light source moves within the window 10 to the center of the television screen. To drive, the AND gate (m) is opened and a drive pulse is sent to the drive motor. Conversely, when there is no image of the slit light source within window 0 and no single slit detection signal is output, the motor pulse gate circuit detects the slit light source. In order to move the slit light source in the opposite direction, the AND gate (N) is opened and the motor is driven in the opposite direction, so that the TV camera always rotates back and forth around the direction of the slit light source, and the AND gate (N) is moved in the opposite direction. ) (W) are added and subtracted in the up-down counter, and the counting data in the up-down counter during that time is transferred to a computer to calculate the direction of the moving body.

When only one set of television camera and measuring device is used, only the orientation of the moving object with respect to the double slit light source is detected, so information regarding the running speed from a speedometer etc. is also used to detect the moving object's timing. The computer calculates the x, y, f, and katana regarding the momentary position and direction, and the steering is controlled depending on whether the calculated values follow a preset course or not.

Next, when using three sets of television cameras and measuring devices,
In the stationary mode, the first measuring device detected the single-slit light source next to the double-slit light source by using the counter (dish) and flip-flop (m) and sending control signals to the motor pulse gate circuit through the computer. The second measurement device stops the drive motor when the next single-slit light source is detected, and the third measurement device starts the drive motor when it detects the next double-slit light source. The motor is stopped and x, y, f, and ri are calculated by the principle of triangulation.

In addition, in the mobile mode, each measuring device
Just as when using only one set of measuring devices, each slit light source is tracked and the momentary x, y, f, and digits are calculated, again based on the principle of triangulation.

When three sets of measuring devices are used in this way, there is an advantage over the case where one set of measuring devices is used in that there is no cumulative error due to integration in the moving mode.

As detailed above, according to the method of the present invention, it is possible to measure the position and orientation of a moving object in a stationary state using a simple measuring device, and the measuring device can also be used when the moving object is subsequently traveling. The position and direction of the vehicle can be easily measured, making it extremely effective for position measurement for automatic travel control of moving objects.

In addition, in the present invention, a slit light source installed vertically on the traveling plane of a moving object is captured by a television camera, and the direction of the television camera is determined when the image is within a vertically long thin window set on the television screen. Since the direction of the slit light source is measured, accurate position and orientation measurements can be made with a simple device.

Brief explanation of the data drawings Figure 1 is an explanatory diagram of the measurement principle of the present invention, Figure 2 is a configuration diagram of the drive mechanism etc. of the television camera that detects the slit light source, and Figure 3 is an illustration of the measurement principle based on the present invention. FIGS. 04 and 6 are explanatory diagrams of a window set on a television screen, and FIG. 5 is a block diagram of a wind gate circuit.

1...Moving object, 2...TV camera,
9... Navigation screen, 10... Window, A, B, C... Starit light source.

Figure 1 Figure 2 Figure 3 Figure 4 Figure 6 Figure 5

Claims (1)

[Claims] 1 Slit light sources that emit light through narrow vertical slits are erected at three reference points around the traveling plane of the moving body, one of which is distinguishable from the other slits, and the above-mentioned A television camera for detecting a slit light source and a measuring device equipped with a slit light source detection circuit and a rotation angle detection circuit connected to the television camera are mounted on a moving object traveling on a running plane to measure the coordinates of the moving object. At this time, the field of view of the television camera is rotated, and the slit light source detection circuit detects an output corresponding to the slit light source based on the video signal corresponding to the slit light source and the window signal corresponding to the vertically long window set on the television screen. A slit detection signal is output when the slit detection signal is within the window, and the rotation angle detection circuit detects the direction of the reference line on the moving body and each of the slit light sources based on the rotation angle of the television camera when the slit detection signal is output. 1. A method for measuring a position of a moving body, the method comprising: measuring the angular relationship between the moving body and the position coordinates and direction of the moving body using a computer.