JP2500894B2 - Parking condition detection system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects the parking state of each parking area in a parking lot using electric power from a common or common electric power line, and obtains the parking state of all parking areas. Concerning the condition detection system.

[0002]

2. Description of the Related Art Recently, a parking state detection system for detecting whether a vehicle is full or empty in a parking lot has been employed.

One of such systems is to count the number of vehicles by a time register, a card system, a photoelectric sensor, etc. at the time of entering and exiting a parking lot, and obtain the difference between the number of entering vehicles and the number of leaving vehicles. There is a system that obtains the difference between the number of parked vehicles and the maximum number of parked vehicles, and displays the parking state whether the vehicle is "full" or "empty".

There is also a parking state detection system for detecting the parking state for each parking area, one example of which is shown in FIG.

In the parking state detection system shown in FIG. 5, a vehicle detection sensor 12 such as a photoelectric sensor is provided above each parking area 11 in which one vehicle 14 is parked in the parking lot 1. A sensor operating current is supplied to the vehicle detection sensor 12 through a power line 13 by a multi-drop method or the like, and each vehicle detection sensor 12 is connected to each parking area 11
Is emitted to detect the parking state of each parking area 11.

Since each vehicle sensor 12 and the central control unit 2 for controlling the entire system are connected via a dedicated communication cable 15, each vehicle detection sensor 1
The parking state detected in 2 is sent to the central control unit 2 to be aggregated, and the parking state in all the parking areas of the parking lot is displayed on the display unit 3.

[0007]

However, in a parking state detection system that counts when entering and leaving a parking lot, a cumulative error may occur in the number of counts, and it is necessary to correct the error from time to time, and at the same time, in each parking area. When it is attempting to detect such a parking state, it is not possible to display the parking state such as which parking area is empty because it has not detected the parking state in However, there is a problem in that it is necessary to provide another detection means.

Further, in the conventional parking state detection system for detecting the parking state for each parking area, it is possible to display which parking area is empty, but each vehicle detection sensor 12 and the central control unit. 2 and communication cable 1
Vehicle detection sensor 1 because it was individually connected via 5
It is necessary to provide the communication cables 15 by the number of two, that is, the number of parking areas 11. Therefore, when the number of parking lots increases, it is necessary to add the communication cables 15 by that amount, which causes a problem that the cost increases and the wiring work and maintenance management become complicated and increase.

Therefore, the present invention has been made in view of such a problem, and can detect even the parking state in each parking area, and even if the number of parked cars is increased by reducing the wiring of communication cables, the cost and It is an object of the present invention to provide a parking state detection system that can prevent an increase in the burden of wiring work and the like.

[0010]

In order to achieve the above object, in the present invention, the electric power from a common or common electric power line is used to detect the parking state of each parking area in a parking lot, and the entire parking area is detected. In the parking state detection system that is configured to obtain the parking state of each of the parking areas, a plurality of ultrasonic sensors for detecting the parking state in each parking area and a predetermined number of parking areas are provided. , A modem connected to each of the ultrasonic sensors provided in each of the parking areas, connected to the modem by a power line, and by power line communication via the modem,
The sensor operation command and transmits to the plurality of ultrasonic sensors according to a pre-planned sequence, a central control unit for determining a parking state of all parking areas to collect the parking state in which the plurality of ultrasonic sensor detects, the Have each ultrasonic sensor
Of the ultrasonic wave interferes with the transmitted and reflected waves of other ultrasonic sensors.
Once with a timely interval and order
Only the primary control wave is transmitted and only the primary reflected wave is received.
In the section, the reflected wave accompanying ultrasonic transmission is
If only received at a time corresponding to the first time
If it is, the vehicle is judged to be in a four-wheeled vehicle and the
When the wave is empty and is longer than the first time,
When it is received only in the corresponding second time, it is judged as an empty vehicle
However, the reflected wave accompanying the ultrasonic wave transmission is
And when both are received during the above second time, the motorcycle is present.
It is determined that the vehicle is a car, and the reflected wave associated with ultrasonic transmission is the first
When both the time and the second time above are not received
Is characterized by being undecidable.

[0011]

The central control unit transmits power to each ultrasonic sensor according to a preset order by power line communication via a modem, and causes each ultrasonic sensor to operate in that order to detect the parking state in each parking area. At the same time, the detected parking states are collected and the parking states of all parking areas are obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A parking condition detection system according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the system configuration of this system.

This system uses the power line communication system in the parking lot 1 which uses the power from the common or common power line 23, so that each parking area 11 in which the vehicle 14 is parked has a "presence". It is intended to detect whether the vehicle is a "car" or an "empty car", and the master modem 21a provided in the central control unit 21 and each parking
Multiple ultrasonic sensors 25 installed in each vehicle area 11
Power line 23 between slave modems 24
It is characterized by performing power line communication.

In the present embodiment, the slave modem 24 controls each of the seven ultrasonic sensors 25 because the parking area 11 constitutes one section for seven vehicles as shown in the figure.
So that, for example, the signal line 22 such as RS232C
Connected to each ultrasonic sensor 25 and used the power line 23
The security information sent from the central control unit 21 by power line communication.
Sensor operation in a multi-drop format based on the sensor operation command.
The movement command is transmitted to each ultrasonic sensor 25, and the parking state detected by each ultrasonic sensor 25 is held as parking information.

The central controller 21 controls each slave modem 24.
And a master modem 21a connected by a power line 23,
The power line communication using a power line 23 via the master modem 21a, details interference or reception waves to be described later but ultrasound, the node address of the slave modem 24 according to a pre-planned order to be able to prevent the influence of the reverberation and It has a sensor operation command section 21b for transmitting a sensor operation command in which the sub-address of each ultrasonic sensor 25 is set to each slave modem 24, and a parking information collection section 21c.

The parking information collection unit 21c communicates with each slave modem 24 by power line communication using the power line 23, for example, in a 1: n polling selection method at a communication speed of 9600 bps, and each slave modem 24. The parking state of each parking area 11 is determined by collecting the parking information held by the vehicle, determining the state of each parking area 11 based on the parking information, such as “in-vehicle”, “empty”, “undetermined” And is displayed on the display unit 3.

FIG. 2 shows an example of the configuration of modems used as the slave modem 24 and the master modem 21a.

The hardware configuration of the slave modem 24 and the master modem 21a is the same. The difference is that the setting mode in the mode setter is set to "slave" or "master", which will be described later. In the case of the slave modem 24, the ultrasonic sensor 25 managed by the slave modem 24 is connected, and the program for operating it is stored.
The case of 4 will be described with reference numerals.

The modem 24 is connected to the power source transformer Tr24a directly connected to the power line 23 and the primary side of the power source transformer 24a via the carrier path capacitors C1 and C2, and has a function of separating a received signal from an AC power source. An isolation unit 24b having a function of superimposing a transmission signal on the AC side, and a digital logic circuit (D
LC: Digital Logic Controller) 24c, isolation unit 24b, and carrier path capacitor C
Data link level power line modem (including output line) that is connected via 3 and C4 and communicates in spread spectrum (SS) system (9600bps to 100kbps)
Data Link Processor (DLP) 24 that functions as
d, isolation unit 24b, DLP 24c
And a DC power supply 24e for transmitting a driving stabilizing current to the DLP 24d.

The digital logic circuit (DLC) 24
Although not shown, C is a CPU, ROM, RAM, address setting unit, mode setting unit, RS2 for IN and OUT.
It has an interface such as 32C and is configured to control the entire modem. When using this modem as the slave modem 24, first, as described above, the mode setter is switched to the "slave" side, and
The seven ultrasonic sensors 25 managed by this modem are connected in advance via the interface of the DLC 24c, and the CPU operates the sensor operation command unit 21 as described later in detail in the ROM.
Each of the seven ultrasonic sensors 2 while switching the sensor operation command according to the sub-address designated by b.
5, a program for operating to store the parking state detected by each ultrasonic sensor 25 in the RAM as parking information is stored. When using this modem as the master modem 21a, the mode setter may be switched to the "master" side.

FIG. 3 shows an ultrasonic sensor 2 according to this embodiment.
5 shows the operation and arrangement of No.5. Each ultrasonic sensor 25
Is a ceiling 1a above each parking area 11 in the parking lot 1.
Signal line 2 from the slave modem 24
Each ultrasonic sensor 2 based on the sensor operation command via
While transmitting ultrasonic waves to the parking area 11 in charge of each at intervals and in order so that the transmitted and received waves of 5 do not overlap,
It is configured to both transmit and receive so as to receive the reflected wave.

In other words, the ultrasonic wave transmitted from the ultrasonic sensor 25 is, for example, stationed so that the reflected wave does not interfere with the transmitted waves of the other ultrasonic sensors 25 and reverberant waves such as the primary reflected wave and the secondary reflected wave. Ultrasonic sensor 2 when the parking lot is small
5 is carried out one by one, while a plurality of ultrasonic sensors 25 may be transmitted at the same time when the parking lot is large, but in either case, it is less affected by the reverberation of other sensors. Plan to select sensors as far as possible.

In addition, in order to eliminate the influence of reverberation, in principle, the transmitted wave is only one block, that is, it is transmitted only once,
The reflected wave uses only the primary reflection for the determination.

As a result, when each ultrasonic sensor 25 is performing the detection operation, the transmitted / received waves of the sensor 25 do not interfere with the transmitted / received waves of the other ultrasonic sensors 25, and there is no reverberation disturbance. Even when the ultrasonic sensor 25, which is cheaper than a photoelectric sensor or the like, is used, each parking area 11
It is possible to accurately detect the parking state of the vehicle.

A specific example of the ultrasonic sensor 25 used in this embodiment is a voice coil horn sensor,
A ceramic sensor or the like may be considered. In the case of a voice coil horn sensor, oscillation is performed by an oscillation circuit and an amplifier, while in the case of a ceramic sensor, oscillation is performed by a natural oscillator and an amplifier. Set so that the center of area 11 can be covered.

Then, as a measure against the delay of the oscillation start time, each ultrasonic sensor 25 is always set to the oscillation standby state and oscillated in a short time by the sensor operation command, and the sensor operation command unit 21b of the central control unit 21. Stop after a certain time set in. To re-oscillate the sensor, stop the sensor operation command after sending it, and then restart the sensor operation command after a certain period of time, as in the case of commands to other sensors considering interference with reflected waves and reverberation. Try to send.

Further, as a countermeasure against self-resonance, the sensors are selected in such an order as to reduce the self-resonance.

Next, the operation of the thus-configured parking state detection system will be described with reference to the drawings.

First, referring to FIG. 1, the master modem 21a
By the power line communication via the power line 23 and the power line 23, the sensor operation command is transmitted from the sensor operation command unit 21b of the central control unit 21 to each slave modem 24 in a predetermined order, and at the same time in each parking area 11. In order to detect the parking state for each time, a polling frame is transmitted from the parking information collection unit 21c at each predetermined time.

In each slave modem 24, the DLC 24c
(See FIG. 2) receives the sensor operation command addressed to its own node (modem), and sets the ultrasonic sensor 25 managed by itself based on subaddresses set in advance in order not to be disturbed by interference or reverberation. Select and transmit a sensor operation command to cause each ultrasonic sensor 25 to transmit an ultrasonic wave,
The reflected wave is received.

The ultrasonic wave transmission cycle of the ultrasonic sensor 25, the method of determining the parking state based on the received wave detected by the ultrasonic sensor 25, etc. will be described in detail with reference to FIG.

FIG. 4 shows an ultrasonic wave transmission cycle in the ultrasonic sensor 25.

Each slave modem 24 has a sensor so that transmitted and received waves of adjacent sensors do not cause reverberation interference due to mutual interference or secondary reflection, tertiary reflection, etc., with respect to each ultrasonic sensor 25 managed by each slave modem 24. The sensor operation instruction A is transmitted in the transmission cycle and order set by the operation instruction unit 21b.

Each of the ultrasonic sensors 25 receives the sensor operation command A and transmits an ultrasonic wave B at a timing delayed by a predetermined time td which will be described later, and from the floor of the parking lot depending on the parking state of the parking area 11. The reflected wave C or the reflected wave D from the vehicle is received.

In the figure, td is the time (ms) from when the sensor operation command is received until effective oscillation occurs, to is the oscillation continuation time (ms) for one sensor operation command, and to 'is the reflection from the floor. Wave duration (ms), to '' is the reflected wave duration (ms) from the vehicle, t1 is the reflection time (ms) from the ultrasonic wave being emitted until the reflected wave returns from the floor, and t2 is Reflection time (ms) from the time when the ultrasonic wave is transmitted until the reflected wave returns from the vehicle, t3 is the dead time (ms) required between the reflection time from the floor and the reflection time from the vehicle, Is shown.

Here, as shown in FIG. 3, when the distance from the parking floor to the ceiling is h (m), the vehicle height is a (m), and the sound velocity is v (m / s), the reflection time is t1 and t2 are t1 = 2h / v (sec) and t2 = 2 (ha) / v (sec), respectively. Further, here, when the oscillation continuation time to in each ultrasonic sensor 25 is obtained, it can be considered that tod = 2 to 3 (ms) and approximately to = to ′ = t0 ″ from the characteristics of the ultrasonic sensor 25. Therefore, the oscillation continuation time to has only to satisfy the following expression (1).

2a / v ≧ 2to + t3 (1) Here, when a = 0.5 to 2 (m) and v = 340 (m / s), 2a / v ( ms) becomes 2 (0.5 to 2) × 1000/340 = 3 to 12 (ms) ... (2). Here, assuming that t3 = 1 (ms), the formula (1) has the following formula: (3-12) -1≥2to (1.5-6) -0.5≥toto≤1-5. When = 1 (ms), the transmission duration time t
It is necessary to set o ≤ 1 to 5.5 (ms).

Next, a method of determining the parking state in each parking area will be described.

In FIG. 4, first, the slave modem 2
The DLC 24c in 4 starts a timer (for example, in units of 0.1 (ms)) by an internal clock (not shown) from time T0, and at each time slot (for example, to '′ between T3 and T4 and between T5 and T6). 8 if ', to' is about 1 (ms)
Every 10 bits), the received signal of the reflected wave is amplified and read, and the presence or absence of the reflected wave for each time slot is set to "1",
It is detected as "0" and is stored in the RAM or the like as parking information.

Each time the slave modem 24 receives a polling frame from the parking information collecting section 21c, it selects the ultrasonic sensor 24 according to the subaddress set in the polling frame, and the ultrasonic sensor 24 is parked. The information is read from the RAM or the like, the parking information is placed on the response frame, and the parking information collecting unit 2
Send to 1c.

In the parking information collecting section 21c, the power line 23,
And by power line communication via the master modem 21a,
A response frame is received from each slave modem 24, the parking information included in the response frame is extracted, and the parking state in each parking area 11 is determined.

That is, in the parking information collection unit 21c, based on the retrieved parking information, it is first determined whether or not the reflected wave can be detected at both T3 to T4 or T5 to T6, for example, 8 bits. In the time slot of, the judgment result is represented by "1" and "0" for both T3 to T4 and T5 to T6 by judging whether or not "1" is set for 4 bits or more. Then, the parking state of each parking area 11 is determined based on the following criteria.

In case of "1" between T3 and T4 and in "0" between T5 and T6 → "Vehicle (four-wheeled vehicle)" In case of "0" between T3 and T4 and "1" between T5 and T6 →
"Empty car" In case of "1" between T3 and T4 and "1" between T5 and T6 →
"Vehicle (motorcycle)" T3 to T4 "0" and T5 to T6 "0" →
“Undecidable” If it is determined as “undecidable”, it is considered that the ultrasonic sensor 25 is out of order, or there is a truck with a hood that does not easily reflect ultrasonic waves. Therefore, it may be possible to conclude that "failure" or "in-vehicle (truck with hood)" depending on the frequency of sensor failure and the frequency of parking of the truck with hood.

In the above description, the presence or absence of the reflected wave is detected for each time slot between T3 and T4 and between T5 and T6, and whether the reflected wave has returned between T3 and T4 or between T5 and T6. It is explained that the central control unit 21 determines the parking state and the parking state is obtained. However, between T3 and T4 and between T5 and T4.
Received signal by reflected wave between 6
Differentiate by the condenser etc. provided in 4, that is, "1", "0" indicating "in-vehicle" or "empty" state by detecting rising
Alternatively, the parking information may be stored as the parking information and returned to the central control unit 21. In either case, t1,
By setting t2, t3, etc., that is, the timings T1 to T6 by the sensor operation command section 21b of the central control section 21, centralized control can be performed, which is convenient for system determination.

Then, in the parking information collecting unit 21c, after judging the parking state in each parking area 11, the display unit 3
In which parking area 11 is “in-vehicle”
The parking state of each parking area 11 such as whether it is in a state or in an “empty” state, and which ultrasonic sensor 25 in the parking area 11 is “faulty” or “normal” Display.

In the polling selection system communication, usually, in addition to the sub-address for selecting each ultrasonic sensor 25 , the node address of the slave modem 25 indicating the transmission destination and the transmission source of the frame is included in the polling frame and the response frame. Since the parking information collection unit 21c receives the response frame, if there is a slave modem 24 that cannot receive the response frame even after the response limit time elapses, the parking information collection unit 21c detects that the response limit time has expired. It is also possible to detect a failure of the slave modem 24 by detecting an abnormality due to resending or the like, and display this on the display unit 3.

Therefore, according to the present embodiment, since the parking state in each parking area 11 is detected by the power line communication using the power line 23, the communication cable for collecting the parking state in each parking area is provided at the center. Control unit 21
And the ultrasonic sensor 25 need not be provided between them, and wiring can be saved.

Therefore, even if the number of parked cars increases,
This can be dealt with by slightly increasing the number of power lines and additionally setting the node address and the sub address in the central control unit 21, thus preventing the cost and the burden of wiring work from increasing.

Further, in this embodiment, as a means for detecting the parking state of each parking area 11, an ultrasonic sensor which is generally cheaper than a photoelectric sensor or the like is used, and the transmitted and received waves of each ultrasonic sensor are mutually connected. Since it was used by transmitting so as not to cause reverberation interference due to interference, secondary reflection, tertiary reflection, etc., there is no need for laying work such as burying the receiving part on the floor surface like in the case of photoelectric sensors, etc. Also in that respect, the effect of reducing the cost can be obtained.

[0051]

As described above, in the present invention, an ultrasonic sensor is provided for each parking area, and each ultrasonic sensor is connected to the central control unit via a modem, and the central control unit operates the modem. Through the power line communication via, by transmitting a sensor operation command to each ultrasonic sensor in accordance with a pre-planned order, collect the parking state detected by each ultrasonic sensor, so as to obtain the parking state of all parking areas, It is not necessary to provide a communication cable for collecting the parking state of each parking area between the central control unit and each sensor, and wiring can be saved. Therefore, even if the number of parked vehicles increases, it can be dealt with by only adding a few power lines, and it is possible to prevent an increase in cost and burden of wiring work.

Therefore, even if the number of parked cars increases,
It can be dealt with only by adding a few power lines,
It is possible to prevent an increase in cost and burden of wiring work.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a system configuration of a parking state detection system according to the present invention.

FIG. 2 is a block diagram showing a configuration of a slave modem.

FIG. 3 is an explanatory diagram showing an operating state of the ultrasonic sensor.

FIG. 4 is a time chart showing a transmission cycle and the like in the ultrasonic sensor.

FIG. 5 is an explanatory diagram showing an example of a conventional parking state detection system.

[Explanation of symbols]

1 Parking Lot 3 Display 11 Parking Area 14 Vehicle 21 Central Control 22 Signal Line 23 Power Line 24 Slave Modem 25 Ultrasonic Sensor

Claims (1)

(57) [Claims] 1. A parking state detection system for detecting a parking state of each parking area in a parking lot by using electric power from a common or common electric power line to obtain a parking state of all parking areas. A plurality of ultrasonic sensors provided for each parking area to detect the parking state in each parking area, and a plurality of ultrasonic sensors provided for each predetermined number of parking areas The connected modem is connected to the modem by a power line, and power line communication via the modem transmits a sensor operation command to the plurality of ultrasonic sensors according to a pre-planned order, and the plurality of ultrasonic sensors. but has a central control unit for determining a parking state of all parking areas to collect the parking state is detected, the transmission wave of the ultrasonic sensor other ultra sound The transmitted wave from the wave sensor
Transmitted at intervals and sequences that do not interfere with reflected waves
In addition, it is transmitted only once and only the primary reflected wave is received.
In the central control unit, the reflected wave associated with the ultrasonic wave transmission is detected by the four-wheeled vehicle.
When received only at a time corresponding to the first time of
Is judged to be in a four-wheeled vehicle, and the reflected wave accompanying ultrasonic transmission is longer than the first time.
Received only in the second time, which is equivalent to the time in the case of an empty car
When it is carried out, it is determined that the vehicle is empty, and the reflected wave accompanying ultrasonic transmission is
When both are received in the second time, it means that the motorcycle is in use.
It is determined that the reflected wave accompanying the ultrasonic transmission is the first time and
If neither is received during the second time, it cannot be determined.
A parking condition detection system characterized by: