JPS6233637B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a so-called pulse radar that periodically transmits ultrasonic pulses or optical pulses toward a parking area and detects the presence of parked vehicles based on the presence or absence of reflected waves. This paper relates to the improvement of on-street parking meters using parking detectors.

BACKGROUND ART As an example, FIG. 3 shows a configuration example of a conventional on-road parking meter using a pulse radar type parking detector using ultrasonic pulses. The pulse radar parking detector 1 transmits ultrasonic pulses from a transmitter 2 toward a parking area, and receives reflected waves from vehicles parked in the parking area with a receiver 3. The device detects the presence of a parked vehicle based on the presence or absence of a vehicle, and includes timing generators 101 and 102, an oscillator 103, and a receiving amplifier 1 for vehicle detection.
04, a rectifying circuit 105, and a level comparator 106 including an integrating circuit. 4 is a parking time measurement circuit that measures the parking time required for parking management based on the detection output output from the pulse radar parking detector 1; 5 is a non-payment display circuit; 6 is a parking time violation display circuit; 7 8 is a parking time display circuit, and 8 is a power supply circuit that intermittently supplies operating power to the pulse radar type parking detector 1 at regular intervals.

The operation of the conventional on-road parking meter having the above structure will be briefly explained with reference to the time chart shown in FIG. The chart waveforms in FIG. 4 correspond to the waveforms in positions E to I in FIG. 3.

In general, this type of on-road parking meter is configured to supply power to the pulse radar parking detector 1, which consumes the most power, only when a vehicle is detected, thereby saving power. That is, a detection timing pulse consisting of a fixed time interval _t1 is applied to the timing generation circuit 801 of the power supply circuit 8,
The power switch 8 is activated by the timing generator 801.
02 is periodically turned on and off in a constant time width _t2 as shown in the chart, thereby intermittently supplying power to the pulse radar type parking detector 1.

When power is intermittently supplied at a constant period _t1 as described above, the timing generators 101 and 102
The pulses are generated at the timings shown in the diagrams. The oscillator 103 receives the output pulse 2 of the timing generator 102 and has a pulse width t ₃
The transmitter 2 periodically transmits ultrasonic pulses shown in the chart toward the parking area.

When the ultrasonic pulse transmitted from the transmitter 2 is reflected by a vehicle parked in the parking area and is received by the receiver 3 during time _t4 as a reflected pulse shown in the chart, the receiving amplifier 104 After this is taken in and rectified by a rectifier circuit 105, the rectified output is integrated by a level comparator 106, and when the integrated value is above a certain level, it is determined that there is a parked vehicle, and a detection output shown in chart is generated. Upon receiving this detection output, the parking time measurement circuit 4 measures the parking time, controls the parking time display circuit 7, the parking time violation display circuit 6, and the unpaid toll display circuit 5 to perform necessary display. It performs predetermined parking management as a parking meter.

Although the above explanation is based on the case where ultrasonic pulses are used, the detection principle is the same when using optical pulses, and the transmitter 2 and receiver 3 in FIG.
Instead, a light transmitter and a light receiver may be used. In addition,
In the case of optical pulses, the reflection time of light can be considered zero, so in general, the transmitter and receiver are adjusted so that the transmitted and received light waves are independent, and consideration is given to prevent transmitted light from leaking to the receiving side. are doing.

Problems to be Solved by the Invention The conventional on-road parking meter using a pulse radar parking detector detects parked vehicles and performs parking management while saving power as a device as described above. . However, as is clear from the charts in FIG. 4, in the conventional on-road parking meter, as soon as the receiver 3 receives the reflected pulse, it determines that there is a parked vehicle, and the parking time measurement circuit 4 immediately starts operating. At the same time, as soon as the reflected pulse disappeared, it was determined that parking had ended, and the parking time measuring circuit 4 immediately started the parking end operation.
Therefore, if even one pulse of noise above the detection level is input to the receiver 3, this noise pulse will be determined to indicate the presence of a vehicle, or if the reflected pulse from the vehicle is detected for a short period of time due to some kind of accident while the vehicle is parked. However, if it ran out, it would be assumed that parking had ended, and there was a risk that the parking meter would malfunction. Generally, this type of on-street parking meter is often installed unmanned, and the occurrence of the above malfunction not only causes inconvenience to users, but also
It may cause trouble. Therefore, it is desirable to further improve the operational reliability of this type of on-road parking meter.

Means for Solving the Problems In order to solve the above problems, the present invention detects the presence of a vehicle in a parking area by a pulse radar parking detector using ultrasonic waves or light. In an on-road parking meter configured to perform parking control such as parking start and parking end based on the detection output of the parking detector, the detection output of the parking detector is input and the presence of the input is detected at each cycle of vehicle detection timing. and generates a presence output indicating the presence of a vehicle when the detection output of the parking detector is detected consecutively a predetermined number of times, and when there is no detection output of the parking detector consecutively a predetermined number of times. An output logic circuit that generates an absence output indicating the absence of a vehicle is connected to the vehicle, and parking control is performed based on the output of the output logic circuit.

Operation When the pulse radar parking detector detects the presence of a vehicle and generates a detection output, the output logic circuit detects the presence of this detection output at each cycle of vehicle detection timing, and the number of consecutive detections is determined in advance. When the number of times reached is reached, a vehicle presence output indicating the presence of a vehicle is generated. The parking start operation is started by this vehicle presence output. Therefore, even if one or several pseudo pulses such as noise pulses are input, this will not cause malfunctions as in the conventional case.

On the other hand, when the vehicle exits and parking is completed, the pulse radar type parking detector detects this and the detection output disappears, but the output logic circuit detects the disappearance of this detection output by adjusting the vehicle detection timing. Detection is performed every cycle, and when the number of consecutive detections reaches a predetermined number, an absence output indicating the absence of a vehicle is generated. The parking end operation is started by this absence output. Therefore, even if one pulse or several pulses of reflected waves from the vehicle are lost due to some kind of accident during parking, this eliminates the erroneous determination that parking is complete as in the conventional case.

Embodiment FIG. 1 shows one embodiment of the present invention. In addition, in the figure, the same reference numerals as in FIG. 3 indicate the same circuits.

As is clear from the drawings, the present invention includes
The detection output of the parking detector 1 is input between the pulse radar parking detector 1 and the parking time measurement circuit 4 in a conventional on-road parking meter, and the presence of this detection output is determined by a logical value of "1" and the absence thereof is determined by a logic value of "1". The presence or absence of the detection output is detected every cycle of the vehicle detection timing with the logical value "0", and when the logical value "1" is detected a predetermined number of times in succession, a vehicle presence output is generated, and a predetermined Logical value “0” several times in a row
An output logic circuit 9 is connected thereto, which generates an absent output when detecting an absence output. In the illustrated example, the output logic circuit 9 is composed of a shift register 91, a flip-flop 92, AND gates 93, 94, and a NOR gate 95.

The operation of the on-road parking meter of the present invention having the above structure will be explained with reference to the time chart of FIG. In addition, each chart waveform in Fig. 2
This corresponds to each waveform at positions 1 to 1 in the figure.

The operation of detecting a parked vehicle by the pulse radar type parking detector 1 shown in FIG. 1 is similar to that of the conventional on-road parking meter described in FIGS. 3 and 4.

When the pulse radar type parking detector 1 detects a vehicle parked in a parking area from its reflected pulse, it outputs a detection output as in the conventional case. The AND gate 93 of the output logic circuit 9 receives this detection output G and the output pulse D of the timing generator 102 as gate inputs and generates an output "1", setting the flip-flop 92 to set Q="1". When the output Q="1" of this flip-flop 92 is input to the shift register 91, the shift register 92
1 reads this Q="1" at the falling position of the output pulse H of the timing generator 101, and generates an output " ₁ " at the first output Q1 of the shift register 91.

Then, after a certain period _t1 has elapsed and the next detection timing arrives, the next output pulse from the timing generator 101 is input to the reset terminal of the flip-flop 92, and the flip-flop 92 is reset at the rising position of the pulse, so that Q = "0". ” becomes. Subsequently, the output pulse N is given to the AND gate 93 from the timing generator 102, but if at this time the pulse radar type parking detector 1 continues to output the detection output G indicating the presence of a vehicle, then the AND gate is applied.
The output of the gate 93 becomes "1", and the flip-flop 92 is set again so that Q="1". The second Q="1" of this flip-flop 92
is input to the shift register 91, and the shift register 91 reads this again and stores the data previously read.
Shift Q ₁ = “1” to Q ₂ and set Q ₂ = “1”, and change the Q of the flip-flop 92 read this time.
= “1” is output to the Q ₁ position as Q ₁ = “1”.

As described above, the above operation is executed for each cycle of the vehicle detection timing, and the detection outputs of the pulse radar parking detector 1 at that time are stored one after another in the outputs Q ₁ to Q _o of the shift register 92. To go. Therefore, if the detection output G of the pulse radar parking detector 1 is occurring continuously for n detection timing pulses I, the outputs Q ₁ to Q _o of the shift register 91 are all output "1". ” becomes. As a result, the output of the AND gate 94 becomes "1", and this output "1" is output as the inventory output.

The parking time measurement circuit 4 is connected to this AND gate 94.
By receiving the inventory output "1" from the controller, it is determined that the vehicle is parked in the parking area, and necessary parking management such as starting to measure parking time and checking for overtime parking is performed.

If the output of the parking detector 1 is interrupted even once during the n measurements, any one of the outputs Q ₁ to Q _o of the shift register 91 corresponding to the position becomes “0”.
Therefore, the AND gate 91 has an output of "0" and cannot generate an inventory output of "1". Therefore, the predetermined number of vehicle detection timing cycles n
As long as the detection output of the parking detector 1 is not detected twice in a row, the output logic circuit 9 will no longer judge that there is a parked vehicle.

On the other hand, when parking is completed and the vehicle leaves the parking area, the detection output of the parking detector 1 becomes "0". Therefore, the output of the AND gate 93 is always in the "0" state, the flip-flop 92 is reset, and its output Q is always in the "0" state.
Therefore, every time the shift register 91 reads Q="0" of the flip-flop 92, it outputs "0" to the corresponding outputs _Q1 to _Qo , and reads Q="0" of the flip-flop 92 n times. sometimes
Q ₁ to Q _o are all “0”. When Q ₁ to Q _o of the shift register are all “0”, NOR
The gate 95 outputs "1", and the output "1" is applied to the parking time measuring circuit 4 as an absent output. Therefore, even if the detection output of the parking detector 1 is interrupted for one pulse or several pulses due to some kind of accident while the vehicle is parked, the NOR signal will be output as long as the detection output is not interrupted for a predetermined number of times. The output of the gate 95 no longer becomes "1", and it is possible to reliably determine whether the parked vehicle is leaving the vehicle.

The above explanation has been made regarding the case where both the vehicle presence output and the absence output are continuously detected for the same number of consecutive times n times, but the maximum number of outputs Q ₁ to _{Q o} of the shift register 91 The number of detections within n can be freely set.

Effects of the Invention The present invention has the configuration and operation as described above, and determines that parking has started when the presence of a vehicle is detected consecutively for a predetermined number of times,
It is determined that parking is complete when the absence of a vehicle is detected continuously for a predetermined number of times.This type of parking meter prevents false detection of a vehicle due to false signals such as noise pulses. This has the excellent effect of significantly improving the reliability of the operation.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of one embodiment of the on-street parking meter according to the present invention, Fig. 2 is a time chart of its operation, Fig. 3 is a circuit diagram showing the configuration of a conventional on-street parking meter, and Fig. 4 is its circuit diagram. This is a time chart of the operation. 1... Pulse radar parking detector, 2... Transmitter, 3... Receiver, 4... Parking time measurement circuit, 8
...Power supply circuit, 9...Output logic circuit, 91...
...Shift register, 92...Flip-flop,
93, 94...AND gate, 95...NOR gate.

Claims (1)

[Claims] 1 A pulse radar parking detector using ultrasonic waves or light detects the presence of a vehicle in a parking area, and parking control such as starting and ending parking is performed based on the detection output of the parking detector. In the configured on-road parking meter, the presence of the input is detected at each cycle of vehicle detection timing using the detection output of the parking detector as an input, and the detection output of the parking detector is continuously detected a predetermined number of times. an output logic circuit that generates a presence output indicating the presence of a vehicle when the vehicle is present, and generates an absence output indicating the absence of a vehicle when there is no detection output from the parking detector for a predetermined number of consecutive times; An on-road parking meter, characterized in that parking control is performed based on the output of the output logic circuit.